JPH0580149B2 - - Google Patents

Description

[Detailed description of the invention]

<Technical Field> The present invention relates to an automatic precision alignment system for semiconductor wafers, and more specifically, a system for automatically aligning semiconductor wafers, and more specifically, a system for automatically aligning semiconductor wafers, and more specifically, a system for automatically aligning semiconductor wafers, and more specifically, a system for automatically aligning semiconductor wafers. The present invention relates to an automatic precision positioning system for positioning a semiconductor wafer, each of which has a circuit pattern in a plurality of rectangular areas, at a desired position. <Background Art> As is well known, on the surface of a semiconductor wafer, there are a plurality of linear regions having a predetermined width and arranged in a lattice shape at predetermined intervals. Such a linear region is
It is generally called a street. A circuit pattern is applied to a plurality of rectangular areas partitioned by linear areas. Such a semiconductor wafer is cut in the linear region, and a plurality of rectangular regions each having a circuit pattern are thus separated. Individually separated rectangular areas are commonly referred to as chips. It is important to cut the semiconductor wafer with sufficient precision in the linear region, and the width of the linear region itself is extremely narrow, generally on the order of several tens of micrometers. Therefore, when cutting a semiconductor wafer with a cutting means such as a diamond blade, it is necessary to align the semiconductor wafer with great precision with respect to the cutting means. Various types of automatic precision positioning systems have already been proposed and put into practical use for positioning semiconductor wafers at desired positions with sufficient precision for the above-mentioned cutting and the like. In such an automatic precision alignment system, the semiconductor wafer is roughly positioned using an orientation flat formed at the edge of the semiconductor wafer and fed onto the holding means, and the semiconductor wafer is fed onto the holding means. The relative position of the linear region is detected with sufficient precision, and based on this detection, the holding means is moved, thus precisely aligning the semiconductor wafer at the desired position. Detection of the relative position of the linear region in such an automatic precision alignment system generally utilizes a pattern matching method. That is, the pattern of a characteristic specific area on the surface of the semiconductor wafer at a predetermined position, that is, the key pattern, and the position of such key pattern are memorized in advance, and the above-mentioned pattern on the surface of the semiconductor wafer to be aligned is stored. A pattern identical to the key pattern is detected, thus detecting the relative position of the linear region. However, conventional automatic precision alignment systems that use pattern matching methods to detect the relative positions of linear regions do not require comparison on the surface of a semiconductor wafer to properly detect the relative positions of linear regions. It is necessary to carry out pattern matching over a wide range of areas, and therefore it takes a considerable amount of time, which has the serious drawback that it impedes the speeding up of semiconductor wafer processing steps such as the above-mentioned cutting. . On the other hand, Patent Application No. 162031 filed in 1982 by the present applicant (title of invention: automatic precision positioning system, filing date: September 5, 1988), specification and drawings (JP-A-60-54454) No. 3, No. 3, No. 3, No. 3, No. 3, No. 3, No. 1, No. 1, No. 1, March 2006, and JP-A No. 2003-11100, an automatic precision positioning system that uses a unique straight line detection method to detect the position of at least one side edge of the above-mentioned linear region, and thus detects the relative position of the above-mentioned linear region. Proposed. In such an automatic precision alignment system, the relative position of a linear region can be detected considerably more quickly than in a conventional automatic precision alignment system that uses a pattern matching method, and therefore the It is possible to sufficiently cope with speeding up the wafer processing process. However, the automatic precision alignment system proposed in the specification and drawings of Patent Application No. 162031 of 1982 has a very small possibility of If there are many straight lines that approximate the side edges of the linear area in the circuit pattern being applied,
Such a straight line is erroneously detected as a side edge of a straight line area,
It has thus been found that there is a possibility that an error may occur in the positioning of the semiconductor wafer. <Object of the Invention> The present invention has been made in view of the above facts, and its main purpose is to provide an improvement that allows semiconductor wafers to be positioned at desired positions sufficiently quickly while substantially eliminating the occurrence of errors. The purpose of the present invention is to provide an automated precision alignment system. <Summary of the Invention> As a result of intensive study, the present inventors have determined that a non-pattern matching method, preferably the above-mentioned patent application No.
By combining the detection of the relative position of the linear region by the unique straight line detection method as proposed in the specification and drawings of No. 162031 and the detection of the relative position of the linear region by the pattern matching method, The occurrence of errors in the former detection can be compensated for in the latter detection, and the time required for the latter detection can be considerably shortened by the former detection, thus virtually eliminating the occurrence of errors. Moreover, it has been found that the semiconductor wafer can be positioned at a desired position sufficiently quickly. That is, according to the present invention, there are a plurality of linear regions arranged in a grid on the surface, and each of the plurality of rectangular regions partitioned by the linear regions is provided with a circuit pattern. an automatic precision positioning system for precisely positioning a semiconductor wafer that has been roughly positioned and supplied onto a holding means using an orientation flat; moving the holding means; a moving means for holding the semiconductor wafer;
an imaging means for outputting an analog signal indicating the density of a matrix array pixel; an A/D conversion means for converting the analog signal generated by the imaging means into a multivalued digital signal; and an A/D conversion means. an image frame memory for storing the multi-value digital signal generated by the image frame memory; and an arithmetic processing means for processing the multi-value digital signal stored in the image frame memory to generate a binary digital signal. , linear area detection means for detecting the relative position of the linear area based on the binary digital signal, and thus detecting the relative position of the linear area. a detection means; a key pattern memory for storing a key pattern corresponding to a specific area on the surface of the semiconductor wafer when the semiconductor wafer is in a predetermined position and a multivalued digital signal indicating the position of the key pattern; and the image frame memory. Detecting a pattern identical to the key pattern in the image captured by the imaging means based on the multi-value digital signal stored in the key pattern memory and the multi-value digital signal stored in the key pattern memory. a pattern matching type position detection means for detecting the relative position of the linear area; and the moving means in response to the detection of the relative position of the linear area by the non-pattern matching type position detection means. activating the wafer, thus performing primary positioning of the semiconductor wafer held by the holding means;
Thereafter, the movement means is actuated in accordance with the detection of the relative position of the linear area by the pattern matching type position detection means, and thus the movement for performing secondary positioning of the semiconductor wafer held by the holding means. An automatic precision alignment system is provided, comprising: a control means; <Preferred Specific Example of the Invention> Hereinafter, a specific example of an automatic precision alignment system configured according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 schematically depicts a portion of a semiconductor wafer cutting apparatus equipped with an embodiment of an automatic precision alignment system constructed in accordance with the present invention.
The semiconductor wafers 2 to be cut are supplied by suitable supply means (not shown), which may be of a form known per se.
and placed on the holding means 4.
At this time, for example, by using the orientation flat 6 existing on the wafer 2, the wafer 2 is roughly positioned, although not precisely, and placed on the holding means 4 within a required error range. To explain this point in more detail, as shown in Figure 2,
On the surface of the wafer 2, there are a plurality of linear regions 8 arranged in a grid pattern. These linear regions 8, generally called streets, have a predetermined width w and are arranged at predetermined intervals d. The width of the linear region 8a extending in a specific direction and the width of the linear region 8b extending in a direction perpendicular to the specific direction are as follows:
Although they do not necessarily have to be substantially the same and are often different from each other, they are generally several tens of μm.
That's about it. Further, the distance between the linear regions 8a extending in the specific direction and the distance between the linear regions 8b extending in the direction perpendicular to the specific direction do not necessarily have to be the same, and are often different from each other. Therefore, in the normal wafer 2,
A plurality of rectangular regions 10 are defined by linear regions 8 (8a and 8b). A required circuit pattern is applied to this rectangular area 10. In such a wafer 2, by utilizing the orientation flat, either one of the linear regions 8a or 8b, in the illustrated case, the linear region 8a is aligned in a predetermined reference direction, that is, the x direction ( It is placed on the holding means 4 so that the angle of inclination is within a range of, for example, about ±1.5 degrees to 3.0 degrees with respect to FIG. 1). Continuing the explanation with reference to FIG. 1, the holding means 4, which may be of a known form per se, holds the wafer 2 placed on its surface sufficiently reliably by vacuum suction or the like. This holding means 4 is mounted so as to be movable in the x direction, the y direction, and the θ direction by an appropriate support mechanism (not shown). A displacement means 12 is drivingly connected to the holding means 4 to allow it to be moved with sufficient precision as desired. In the illustrated example, the moving means 12 includes an x-direction movement source 14, a y-direction movement source 16, and a θ-direction movement source 18.
It consists of The x-direction displacement source 14, which advantageously consists of a pulse motor, when activated moves the holding means 4 in the x-direction, e.g.
It moves the required distance with an accuracy of about 1 μm. It is advantageous to consist of a pulse motor.
When activated, the directional movement source 16 moves the holding means 4 a required distance in the y direction, that is, in the direction perpendicular to the x direction, with an accuracy of, for example, about 1 μm.
The θ-direction movement source 18, which likewise advantageously comprises a pulse motor, when actuated, moves the holding means 4 by the required angle in the θ direction with an accuracy of, for example, 0.0015 degrees, i.e., along the central axis of the holding means 4. 2
Rotate around 0. The illustrated semiconductor wafer cutting apparatus includes a rotating blade 22, which is preferably formed from fixed diamond abrasive grains. This rotary blade 22 constituting the wafer cutting means is
It is mounted so as to be rotatable about a central axis 24 that is substantially parallel to the x direction and movable in the x direction, and is driven to rotate at a required speed by an appropriate drive source (not shown) such as an AC motor. and is caused to reciprocate in the x direction at a desired speed by a suitable drive source (not shown) such as a DC motor. In the illustrated semiconductor wafer cutting apparatus, while the holding means 4 is present in the supply and discharge area at or near the position indicated by the solid line in FIG. Holding means 4
The wafer 2 is placed on top. Next, by finely adjusting the position of the holding means 4, as will be described in detail later, the wafer 2 held on the holding means 4 is sufficiently accurately positioned at a predetermined position with respect to the rotating blade 22. . Thereafter, the holding means 4 is advanced a predetermined distance in the y direction, and as shown by the two-dot chain line in FIG.
The cutting start area is located adjacent to the cutting start area. Next, a cutting movement is performed in which the rotary blade 22 is rotated and moved in the x direction so that the wafer 2 is subjected to the action of the rotary blade 22 that is rotationally driven, and the interval between the linear regions 8 existing on the surface of the wafer 2 is performed. Holding means 4 by d+w (Fig. 2)
The wafer 2 is thus cut along the linear region 8b (or 8a) existing on its surface.
Next, the holding means 4 is moved 90 degrees in the θ direction about its central axis 20, and then the above-mentioned cutting movement and the above-mentioned indexing movement are performed alternately, thus moving the wafer 2 into the linear region 8 existing on its surface.
Cut along a (or 8b). After that,
The holding means 4 is moved backwards in the y direction by a predetermined distance to return the holding means 4 to the supply and discharge area. The wafer 2 cut from the holding means 4 is then ejected from the holding means 4 by suitable ejecting means (not shown), which may be of a form known per se, and by means of said feeding means (not shown). )
The next wafer 2 is then placed on the holding means 4. As is well known to those skilled in the art, the cutting of the wafer 2 by the rotating blade 22 is carried out not over the entire thickness of the wafer 2, but with only a small remaining uncut thickness, thus cutting the rectangular area 10.
(FIG. 2) may not be completely separated (in this case, the rectangular area 10 may be completely separated by applying a slight force later to break the uncut portion). , thus producing chips). Alternatively, an adhesive tape may be attached to the back surface of the wafer 2 in advance so that the rectangular regions 10 are not separated into individual parts even when the wafer 2 is cut across its entire thickness. Later, by peeling off the adhesive tape, the rectangular area 10 is completely separated, thus producing a chip). Continuing the explanation with further reference to FIG. 1, in the embodiment shown, the holding means 4 is located above the holding means 4 and the wafer 2 held on its surface when the holding means 4 is present in the supply and discharge areas. A stationary enlarging optical means 26 and an imaging means 28 optically connected to the enlarging optical means 26 are provided. The illustrated enlarging optical means 26 is arranged at appropriate intervals in the x direction.
It consists of a binocular microscope having two light entrance apertures 30a and 30b spaced apart, for example, by about 40 mm. Therefore, images of two portions of the surface of the wafer 2 held on the holding means 4 at a predetermined interval in the x direction are captured by the light input apertures 30a and 3.
The image is input to the enlarging optical means 26 through the optical fiber 0b, enlarged at a required magnification, and sent to the imaging means 28 as a split image. The magnification by the magnifying optical means 26 may be, for example, about 20 times. If desired, a variable magnification optical means can be used which allows the magnification to be changed stepwise or continuously. The imaging means 28 receives x according to the captured image.
- Any type of camera may be used as long as it can output an analog signal indicating the density of pixels arranged in a y matrix, but solid-state cameras, in particular, a plurality of imaging elements arranged in an xy matrix, e.g.
Preferably, it consists of a solid state camera with CCD, CPD or MOS. In the illustrated embodiment, the imaging means 28 comprises a solid state camera having a 256.times.256 CCD arranged in a matrix. The 128 x 256 CCDs located in the left half of the 256 x 256 CCDs receive the image incident on the left light entrance aperture 30a of the enlarging optical means 26, and the remaining CCDs located in the right half 128×256
The image incident on the right light entrance aperture 30b of the enlarging optical means 26 is input to each of the CCDs. 256×
Each of the 256 CCDs outputs an analog signal having a voltage depending on the gray level of the image input to it. The solid-state camera with 256 x 256 CCDs has an automatic gain adjustment means (not shown), known per se, which automatically adjusts the gain of the output analog signal according to the actual density of the captured image. It is convenient if it is attached or built-in. Referring to FIG. 3, which is a block diagram schematically showing various electronic and electrical means provided in connection with the imaging means 28, the output analog signal of the imaging means 28 is an A/D converter. The input analog signal is input to the (analog-to-digital) conversion means 32, and the A/D conversion means 32 converts the input analog signal into, for example, 8
It is converted into a multi-value digital signal with only 2 bits (therefore, 2 ⁸ = 2562 stages). The multivalued digital signal is then sent to the image frame memory 34 and stored there. The image frame memory 34 in the illustrated example has a storage capacity of at least 256 x 256 x 8 bits, and therefore the image capture means 28
256 x 256 solid-state cameras comprising
It consists of a RAM that can store 256 x 256 8-bit multi-value digital signals, each corresponding to the density of 256 x 256 pixels input to the CCD. In the illustrated example, the image frame memory 34 includes a central processing unit (CPU), which may be a microprocessor with a plurality of built-in RAMs.
Connected via 36 is a non-pattern matching position detection means, generally indicated by the numeral 38. Illustrated non-pattern matching position detection means 3
8 is arithmetic processing means 40 and linear area detection means 4
2. The arithmetic processing means 40 has a differential processing circuit 44, a threshold processing circuit 46, and a parity check processing circuit 48. The arithmetic processing means 40 operates in three modes, depending on the operator's selection.
That is, the multivalued digital signal stored in the image frame memory 34 is subjected to arithmetic processing according to any one of the differential calculation processing and threshold processing mode, the simple threshold processing mode, and the threshold processing and parity check processing mode. Generate a binary digital signal. The binary digital signal generated by the arithmetic processing means 40 is then sent to the central processing unit 3.
6 is stored in the built-in RAM. The linear area detection means 42 detects at least one edge of the linear area 8a (or 8b) based on the binary digital signal, and thus detects the relative position of the linear area 8a (or 8b). The non-pattern matching type position detection means 38 including the arithmetic processing means 40 and the linear area detection means 42 is as described in detail in the specification and drawings of Patent Application No. 162031 of 1983. Therefore, the non-pattern matching position detection means 38
For details on the composition and effects of the Showa
The details will be referred to the specification and drawings of Patent Application No. 162031 of 1958, and the description thereof will be omitted in the specification of the present invention. In the illustrated embodiment, a cathode ray tube (CRT)
A display means 5 which is advantageously comprised of
0 is also provided. This display means 50 is displayed in response to manual operation of a switching means (not shown).
The multivalued digital signal outputted by the A/D conversion means 32, the binary digital signal stored in the RAM built in the central processing unit 36, the signal stored in the key pattern memory described later, etc. Selectively display images corresponding to the images. In the illustrated display means 50, the left side light entrance opening 3 of the enlarging optical means 26 is located in its left half.
An image related to the image inputted from 0a to the imaging means 28 is shown in the right half of the image by the enlarging optical means 26.
Images related to the images inputted to the imaging means 28 from the right light entrance aperture 30b are respectively enlarged and displayed at a total magnification of about 260 times, for example. A key pattern memory 5 is stored in the image frame memory 34 via the central processing unit 36.
2 and a pattern matching type position detection means 54 are also connected. The key pattern memory 52, which can be composed of a RAM, stores the pattern of a specific area on the surface of the wafer 2, that is, the key pattern, and the position of the key pattern when the wafer 2 held on the holding means 4 is in a predetermined position. Store the indicated signal. An example of a signal input method to the key pattern memory 52 will be explained as follows. When inputting a signal to the key pattern memory 52, the holding means 4
The sample wafer 2 is placed thereon, and then the x-direction movement source 14, the y-direction movement source 16, and the θ-direction movement source 18 are manually operated as appropriate to move the holding means 4, and the holding means 4 is moved. The sample wafer 2 is manually positioned at a desired position with respect to the magnifying optical means 28. During such manual positioning, the display means 50 is made to visually display the multivalued digital signal outputted by the A/D conversion means 32, and the image displayed on the display means 50 is observed. For example, as schematically shown in FIG. 4, the center line of the linear region 8a on the surface of the sample wafer 2 is arranged so that it substantially coincides with the lateral center line on the display screen of the display means 50, that is, the x-x line. Sample wafer 2 is positioned at . Next, the cursor 55 is manually positioned in the specific areas 56L and 56R on the left half and right half of the display screen of the display means 50, respectively. The cursor 55 and therefore the specific areas 56L and 56R designated by the cursor 55 are
For example, it corresponds to 32 x 32 pixels (therefore, the imaging means 2
It may be a square with dimensions corresponding to 32 x 32 CCDs in 8). It is preferable that the specific regions 56L and 56R specified by the cursor 55 are regions having remarkable features, for example, regions at the intersection of the linear region 8a and the linear region 8b. After that, 32×32= which exists in the specific areas 56L and 56R of the multivalued digital signals stored in the image frame memory 34
Signals corresponding to 1024 pixels are sent to the key pattern memory 52 and stored therein. At the same time, signals indicating the positions (i.e., x and y coordinates) of the specific areas 56L and 56R on the display screen of the display means 50 are also sent to the key pattern memory 52 and stored therein. Thus, the key pattern memory 52 stores a multivalued digital signal indicating the pattern of the specific areas 56L and 56R, that is, a key pattern, and also stores x-coordinate and y-coordinate signals indicating the position of the key pattern. In a preferred embodiment, a secondary key pattern storage operation is performed after the key pattern storage operation as described above. In this sub-key pattern storage operation, the cursor 55 is moved to an appropriate area separate from the specific areas 56L and 56R, that is, a sub-key pattern, in each of the left and right halves of the display screen of the display means 50. Manual positioning is performed in specific areas 58L and 58R. After that, in the same manner as in the key pattern storage operation described above, the sub-specific area 58 is
A multivalued digital signal indicating the L and 58R patterns, that is, the subkey pattern, is stored in the key pattern memory 52. Furthermore, the x-coordinate and y-coordinate signals indicating the position of the sub-key pattern are stored in the key pattern memory 52. When the above-described key pattern storage operation and sub-key pattern storage operation are completed, the θ direction movement source 18 is manually operated to rotate the sample wafer 2 held on the holding means 4 by 90 degrees. Next, the x-direction movement source 14 and the y-direction movement source 16 are operated manually as necessary, thereby forming a linear region 8b on the surface of the sample wafer 2, as schematically shown in FIG. The sample wafer 2 is positioned so that its center line coincides with the lateral center line on the display screen of the display means 50, that is, the line xx. Then, a key pattern storage operation similar to the key pattern storage operation described above is performed. That is, in each of the left half and right half of the display screen of the display means 50, the cursor 55 is manually positioned in the specific areas 60L and 60R, respectively, and then the pattern of the specific areas 60L and 60R, that is, the key pattern is shown. The multivalued digital signal is stored in the key pattern memory 52, and the x-coordinate and y-coordinate signals indicating the position of the key pattern are also stored in the key pattern memory 52. In addition, after rotating the sample wafer 2 by 90 degrees, the central processing unit 3 uses signals indicating the amount of movement in the x and y directions performed to position the sample wafer in the state shown in FIG. 5 as rotational displacement signals.
6 (or in the key pattern memory 52). In a preferred embodiment, a width key pattern storage operation similar to the subkey pattern storage operation described above is further performed after the key pattern storage operation. That is, in each of the left half and right half of the display screen of the display means 50, the cursor 55 is moved to an appropriate area separate from the specific areas 60L and 60R, that is, the sub-specific areas 62L and 62R.
, and then store in the key pattern memory 52 a multilevel digital signal indicating the pattern of the sub-specific areas 62L and 62R, that is, the width key pattern, and also x indicating the position of the sub-key pattern.
The coordinate and y-coordinate signals are stored in the key pattern memory 52. The pattern matching type position detection means 54
on the surface of the wafer 2 held on the holding means 4 and to be automatically positioned at the required position,
The same pattern as the key pattern or the sub-key pattern is detected in the image captured by the imaging means 26, and therefore the image displayed on the display means 50, and the relative position of the linear area 8a or 8b is thus determined. To detect. An example of such pattern matching type position detection will be explained as follows. Among the images input to the imaging means 28 from the left light entrance aperture 30a of the enlarging optical means 26, and therefore the image displayed on the left half of the display screen of the display means 50, there is a key pattern that is the same as the key pattern of the specific area 56L. The case of detecting a pattern will be explained with reference to the flowchart shown in FIG. The matching area to be matched with the key pattern is thus defined. Next, step n-2
Then, the degree of matching P between the matching area and the key pattern is calculated. The calculation P of the degree of matching is based on a multivalued digital signal indicating a key pattern stored in the key pattern memory 52, that is, a 32×32 signal indicating the density of 32×32 pixels in the specific area 56L. a multilevel digital signal,
From the imaging means 28 to the A/D conversion means 3, which indicates the density of 32×32 pixels in the verification area.
It can be calculated based on 32×32 multi-value digital signals among the multi-value digital signals inputted to the image frame memory 34 via 2. The matching degree P itself can be calculated using, for example, the following formula A P = 〓 〓 ^i,j | [f (i, j) -] - [g (i, j) -] |
...A Here, f is the value corresponding to the density of each of the 16 x 16 pixels in the verification area, is the average value of f, and g is the value corresponding to the density of each of the 16 x 16 pixels in the key pattern. is the value corresponding to each density, is the average value of g, (i, j) indicates the row and column of each pixel,
Therefore, it can be calculated based on (i=1 to 16, j=1 to 16). In calculating the matching degree P based on the above formula A, the density deviation value of each pixel in the matching area (that is, the value obtained by subtracting the average density value from the actual density value) and each pixel in the key pattern are calculated. The difference from the concentration deviation value is added,
Therefore, fluctuations in so-called density gain caused by fluctuations in illuminance with respect to the matching area are eliminated, and a sufficiently reliable matching degree P is obtained. In order to simplify the arithmetic processing, the following formula P = 〓 〓 ⁱ is obtained by adding binarization processing to each of [f (i, j) -] and [g (i, j) -] in the above formula A. ^,j |U[f(i,j)−]−U[g(i,j)−
] |...B Here, U means a binarization operation, and when x>0, U(a)=1, and when x≦0, U(a)=0.Based on, the matching degree P You can also ask for In order to further increase the reliability of the required matching degree P, based on the so-called normalized correlation, that is, the following formula B

[Image Omitted] Here, f, , g, and (i, j) are the same as in the case of the above formula A. The matching degree P can also be determined based on the following. Therefore, when calculating the matching degree P based on the above formulas A, B, or C, instead of performing correlation processing on all pixels (32 × 32 = 1024) in the matching area, the calculation speed is increased. In order to achieve this, correlation processing may be performed on only a plurality of specific pixels in the matching area, for example, 32 specific pixels selected one in each row and column. In particular, when calculating the matching degree P based on the above formula C, even if correlation processing is performed only on a plurality of specific pixels among the pixels in the matching area, it is sufficiently good for most semiconductor wafers. It has been confirmed that results can be obtained. Following the calculation of the matching degree P, in step n-3, it is determined whether the calculated matching degree P is greater than or equal to a predetermined threshold value. The predetermined threshold value can be appropriately set by the operator (eg, by trial and error method) and stored in the sea pattern memory 52 or the RAM in the central processing unit 36. If the calculated degree of matching P is not equal to or greater than the predetermined threshold value, that is, if the degree of matching is relatively low, the process proceeds to step n-4, and the magnifying optical means 26
It is determined whether the cursor 55 has been moved over the entire area of the image input to the imaging means 28 from the left side light entrance aperture 30a, and thus the image displayed on the left half of the display screen of the display means 50. Ru. If the movement of the cursor 55 over the entire area has not been completed, the process proceeds to step n-5, where the cursor 55 is moved by one pixel in the x direction and/or y direction and moved to the next matching area. Thereafter, the matching degree P is calculated in the above-mentioned step n-2, and it is determined in step n-3 whether the calculated matching degree P is greater than or equal to a predetermined threshold value. If the calculated degree of matching P is greater than or equal to a predetermined threshold, that is, if the degree of matching is relatively high, the process proceeds from step n-3 to step n-6;
The position of the matching area and the matching degree P are built into the pattern matching type position detection means 54.
It is stored in RAM or RAM built into the central processing unit 36 and restored. Then, proceed to step n-4 above. In this way, the enlarging optical means 26 opens the left light entrance aperture 30a.
The matching degree P is calculated and the calculated matching degree P is greater than or equal to a predetermined threshold value over the entire area of the image input to the imaging means 28 from When the judgment as to whether the
It is determined that the matching area having Pmax is the same as the key pattern, that is, the specific area 56L. In this way, from the position (x and y coordinate position) of the matching area having the maximum matching degree Pmax and the position (x and y coordinate position) of the key pattern, that is, the specific area 56L, it is inevitable that the relative position of the linear area 8a is The position is detected. In the image input to the imaging means 28 from the left light entrance aperture 30a of the enlarging optical means 26, and therefore the image displayed on the left half of the display screen of the display means 50, the sub key pattern of the sub specific area 58L, When detecting the same pattern as the key pattern of the specific area 60L or the sub-key pattern of the sub-specific area 62L, or when detecting the same pattern as the key pattern of the specific area 60L or the sub-key pattern of the sub-specific area 62L, the imaging unit 2
8, and therefore the image displayed on the right half of the display screen of the display means 50, the key pattern of the specific area 56R, the sub key pattern of the sub specific area 58R, and the key pattern of the specific area 60R. When detecting the same pattern as the key pattern or the sub-key pattern of the sub-specific area 62R, the sixth
The same procedure as described above with reference to the flowchart shown in the figure may be performed. The automatic precision alignment system constructed in accordance with the present invention further includes the moving means 12, more specifically an x-direction movement source 14, a y-direction movement source 16.
A movement control means 64 is provided for controlling the operation of the θ-direction movement source 18 and positioning the wafer 2 held on the holding means 4 at a desired position. The movement control means 64 operates the movement means 12 in response to the detection of the relative position of the linear region 8a (or 8b) by the non-pattern matching type position detection means 38, and thus performs the primary positioning of the wafer 2. Thereafter, the moving means 12 is operated in response to the detection of the relative position of the linear area 8a (and 8b) by the pattern matching type position detecting means 54, and thus the secondary positioning of the wafer 2 can be performed. is important. 7-A to 7-C show an example of a flowchart for positioning by the moving means 64. To explain with reference to FIG. 7-A, in step m-1, two images inputted to the imaging means 28, namely, two images inputted to the imaging means 28 from the left side light entrance aperture 30a of the enlarging optical means 26 are inputted to the imaging means 28. or an image inputted into the imaging means 28 from the right side light entrance aperture 30b of the enlargement optical means 26, for example, an image inputted from the left side light entrance aperture 30a of the enlargement optical means 26, It is determined whether the non-pattern matching type position detection means 38 can detect the linear region 8a. The linear region 8a does not exist in the image due to an error in the placement position of the wafer 2 on the holding means 4, or the linear region 8a does not exist in the captured image due to printing defects, etc. If the linear region 8a has disappeared locally and therefore the non-pattern matching type position detection means 38 cannot detect the linear region 8a, the process proceeds to step m-2, and the central processing unit 36 calculates the amount of movement in the y direction. Set. This y
The amount of directional movement may be an appropriate value smaller than the distance d between the linear regions 8a, for example, about 300 μm. Next, the process proceeds to step m-3, where the amount of y-direction movement is added to the current y-direction position of the holding means 4 and the wafer 2 held therein. Next, proceed to step m-4, where the additional movement amount in the y direction and the interval d
are compared. Then, when the interval d is larger (if the y-direction movement amount is further added after the y-direction movement is repeated multiple times, the interval d becomes smaller), proceed to step m-5. , the movement control means 64 operates the y-direction movement source 16 to move the holding means 4 and the wafer 2 held therein in the y direction.
It is moved in the y direction by the amount of directional movement. and,
Return to step m-1 above. Above step m-4
When the distance d is smaller, that is, by adding the amount of movement in the y direction multiple times, the distance d becomes smaller than the added amount of movement in the y direction, and therefore the holding means 4 and the If the held wafer 2 is moved in the y-direction by the amount of movement in the y-direction, and the total amount of movement in the y-direction exceeds the distance d, the process proceeds to step m-6, where the wafer 2 is stored in the central processing unit. The x-direction movement counter is incremented by 1, and then the process proceeds to step m-7, where it is determined whether the count value of the x-direction movement counter has reached 4 (that is, whether the x-direction movement has already been repeated three times). ). If the count value of the x-direction movement counter has not reached 4, the process proceeds to step m-8, in which the movement control means 64 moves the x-direction movement source 14 and causes the holding means 4 and the holding means 4 to hold the x-direction movement source 14. Wafer 2, for example, 170μ
It is moved in the x direction by a predetermined amount, which may be about m.
Next, the process proceeds to step m-9, and the y-direction movement is set to reverse (that is, if the y-direction movement was previously performed in the positive direction, it is set to be performed in the negative direction from now on). be done. The process then proceeds to step m-3. Therefore, in the illustrated example, if the linear region 8a cannot be detected, the holding means 4 and the wafer 2 held therein are moved to y as illustrated by the arrow 66 in FIG. It will be understood that the detection of the linear region 8a is repeated by moving in a so-called zigzag manner in the x-direction and the x-direction (movement in the x-direction is a maximum of three times). In step m-1, if the non-pattern matching type position detection means 38 detects the linear region 8a, the process proceeds to step m-10, and the center in the y direction of the image being imaged (i.e., It is determined whether there is a shift or deviation between the center of the linear region 8a and the center of the linear region 8a. If the deviation exists, the process proceeds to step m-11, where the movement control means 64 activates the y-direction movement source 16 to move the holding means 4 and the wafer 2 held therein in the y-direction by the amount of the deviation. , thereby positioning the linear region 8a at the center in the y direction of the image being captured. After that, the process proceeds to step m-12, and the imaging means 28
Also in the other of the two images input to
In other words, it is determined whether or not the non-pattern matching type detection means 38 detects the linear region 8a in both of the two images input to the imaging means 28. The linear region 8a is connected to the x-x line (the fourth
Due to the fact that the linear region 8a does not exist in the other of the two images, the non-pattern matching position detection means 38 If it is not possible to detect the linear region 8a in both of the two images, the process proceeds to step m-13, where the linear region 8a detected in one of the two images is detected in the x direction. Detect the inclination angle relative to the To detect such an inclination angle, the holding means 4 and the wafer 2 held therein are moved at least once by a predetermined distance in the x direction, and the position of the linear area 8a in the y direction before the movement is compared with the straight line after the movement. It can be conveniently detected based on the difference from the y-direction position of the shaped region 8a. In the specific example shown, a three-point check method is adopted, and the position of the linear area 8a in the y-direction in the image before movement and the holding means 4 are determined by activating the x-direction drive source 14.
and the y-direction position of the linear region 8a after moving the wafer 2 held thereon by a predetermined distance in the x-direction, which may be about 2 mm, and further the x-direction position.
Three y-direction positions of the linear region 8a after activating the directional drive source 14 to further move the holding means 4 and the wafer 2 held therein by the predetermined distance in the x-direction. The inclination angle is detected based on the difference. Once the tilt angle is detected in this manner, the process proceeds to step m-14, where rough alignment in the θ direction is performed in accordance with the detected tilt angle. That is, in accordance with the detected inclination angle, the movement control means 64 drives the θ-direction movement source 18 to move the holding means 4 and the wafer 2 held therein in the θ direction, that is, the center axis 20 (first
(Fig. 4), thereby making the linear region 8a substantially parallel to the x--x line (Fig. 4). When such coarse alignment in the θ direction is performed, as is easily understood, the linear region 8a will exist in both of the two images input to the imaging means 28. In the above step m-12,
If the non-pattern matching type position detection means 38 detects the linear region 8a in both of the above two images, the process proceeds to step m-15. In step m-15, it is determined which of two alignment procedures that can be selected by the operator as appropriate, for example, depending on the characteristics of the wafer 2 to be aligned, is selected. That is, should the primary positioning based on the detection of the relative position of the linear region 8a by the non-pattern matching type position detection means 38 be further continued, or should the relative position of the linear region 8a be detected by the non-pattern matching type position detection means 38? After completing the primary positioning based on position detection, the pattern matching type position detection means 5
It is determined whether to proceed to the secondary positioning based on the detection of the relative positions of the linear regions 8a and 8b by 4. If the former is selected, the process proceeds to step m-16, and the above-mentioned 2 inputs to the imaging means 28 are performed.
y of the linear region 8a detected by the non-pattern matching type position detection means 38 in each of the images.
It is determined whether the directional positions match.
As can be easily understood, if the linear region 8a is not parallel to the x direction with sufficient precision,
There is a difference in the y-direction position of the linear region 8a detected in each of the two images separated at a predetermined interval in the x-direction. If such a difference exists, proceed to step m-17 and perform sufficiently precise θ alignment. That is, in accordance with the above-mentioned difference, the movement control means 64 operates the θ direction movement source 18 to move the holding means 4 and the wafer 2 held therein in the θ direction, so that the linear region 8a can be moved with sufficient precision. It is made parallel to the x direction.
Thereafter, the process proceeds to step m-18, where the central processing unit 36 detects a shift between the center of the image being captured in the y direction (i.e., the line xx shown in FIG. 4) and the center of the linear region 8a. Determine whether a deviation exists. If the above-mentioned deviation exists, the process proceeds to step m-19, where the movement control means 64 operates the y-direction movement source 16 to move the holding means 4 and the wafer 2 held thereon by the above-mentioned deviation. In this way, the linear region 8a is positioned sufficiently precisely at the center of the image being captured in the y direction. Thereafter, the process proceeds to step m-20, in which the movement control means 64 activates the y-direction movement source 16 to move the holding means 4 and the wafer 2 held thereon at a distance d between the linear regions 8a (FIG. 2). ) in the y direction. Next, proceeding to step m-21, the imaging means 28 is again
It is checked whether the non-pattern matching type position detection means 38 detects the linear region 8a in both of the two images inputted. Holding means 4
Since the amount of movement of the wafer 2 held therein in the y direction is the distance d between the linear regions 8a, normally the non-pattern matching type position detection means 38 detects the linear region 8a in both of the above two images. shape area 8
Detect a. However, if it cannot be confirmed that the non-pattern matching type position detection means 38 detects the linear region 8a in both of the above two images due to printing defects, etc., the process proceeds to step m-22. The movement control means 52 drives the x-direction movement source 14 to move the holding means 4 and the wafer 2 held therein in the x-direction by, for example, 200μ.
Move it a predetermined distance, which may be about m, and then,
Proceeding to step m-23, the non-pattern matching type position detection means 38 is applied to both of the above two images.
It is checked again whether or not the linear region 8a is detected. In the above step m-21 or m-23,
When it is confirmed that the non-pattern matching type position detection means 38 detects the linear region 8a in both of the above two images, step m-24 (seventh
-B figure), and thereafter the linear areas 8a and 8 are detected by the pattern matching type position detection means 54.
A secondary alignment based on detection of the relative position of b is performed. Referring to FIG. 7-B, step m
-24, in one (or both) of the two images inputted to the imaging means 28, for example, in the image inputted to the imaging means 28 from the left light entrance aperture 30a of the enlarging optical means 26, a pattern matching method is used. It is determined whether or not the position detection means 54 detects a key pattern, that is, the same pattern as the pattern of the specific area 56L (FIG. 4). When the pattern matching type position detection means 54 does not detect the same pattern as the key pattern, the process proceeds to step m-25, where the central processing unit 36 sets the amount of movement in the x direction. This amount of x-direction movement is an appropriate value smaller than the interval d between the linear regions 8b, for example.
Approximately 300 μm is sufficient. Next, the process proceeds to step m-26, where the x-direction movement amount is added to the current x-direction position of the holding means 4 and the wafer 2 held therein. Next, proceed to step m-27,
The added movement amount in the x direction and the interval d are compared. If the distance d is larger (if the amount of movement in the x direction is further added after the movement in the x direction is repeated multiple times, the distance d becomes smaller), the process proceeds to step m-28. The movement control means 64 operates the x-direction movement source 14 to move the holding means 4 and the wafer 2 held therein in the x-direction by the x-direction movement amount. Then, the above step m-24
Return to In step m-27 above, when the distance d is smaller, that is, by adding the amount of movement in the x direction multiple times, the distance d becomes smaller than the added amount of movement in the x direction, and therefore, the distance d is further held. If the means 4 and the wafer 2 held therein are moved in the x direction by the above x direction movement amount, and the total movement amount in the x direction exceeds the above distance d, step m is performed.
Progress to -29. In step m-29, the y-direction movement counter built in the central processing unit is incremented by 1, and then step m-29 is performed.
30, the count value of the y-direction movement amount counter becomes 2.
(ie, determines whether the movement in the y direction has already been performed once). If the count value of the y-direction movement counter has not reached 4, the process proceeds to step m-31, where the movement control means 64 activates the y-direction movement source 16,
Holding means 4 and wafer 2 held therein
is moved in the y direction by the distance d between the linear regions 8a. Next, the process proceeds to step m-32, where the x-direction movement is set to reverse (that is, if the x-direction movement was previously performed in the positive direction, it is now set to be performed in the negative direction). be done. Thereafter, the process returns to step m-24. Because of this, if the pattern matching type position detection means 54 does not detect the same pattern as the key pattern in the above step m-24, the same procedure as in the above steps m-1 to m-9 is performed. Then, the holding means 4 and the wafer 2 held therein are moved in a so-called zigzag pattern in the x and y directions (the movement in the y direction is only once), and the detection of the same pattern as the key pattern is repeatedly performed. be done. Therefore, at the time when the process proceeds from step m-23 to step m-24, a sufficiently precise primary position based on the detection of the relative position of the linear area 8a by the non-pattern matching type position detection means 38 has already been obtained. Since alignment has been completed, the pattern matching position detecting means 54 does not match the key pattern in step m-24, except in extremely rare cases such as incorrect detection by the non-pattern matching position detecting means 38. Detect identical patterns immediately.
And pattern matching type position detection means 54
If the same pattern as the key pattern is detected, the process proceeds to step m-33, where the center in the y direction (i.e., line xx shown in FIG. 4) and the linear area 8a in the image being captured are It is determined whether there is a shift or deviation from the center. If the above deviation exists, step m-
34, the movement control means 64 moves the y-direction movement source 1
6 is activated, thus positioning the linear region 8a sufficiently precisely at the center of the image being captured in the y direction. Thereafter, the process proceeds to step m-35, in which the movement control means 64 operates the x-direction movement source 14 to move the holding means 4 and the wafer 2 held therein by the distance x of the linear region 8b.
move in the direction. Next, the process proceeds to step m-36, in which it is determined whether the pattern matching type position detection means 54 detects the same pattern as the key pattern in one (or both) of the two images input to the imaging means 28. is confirmed. If it is confirmed that the pattern matching type position detection means 54 detects the same pattern as the key pattern, the process proceeds to step m-37, and the position detection means 54 detects the same pattern as the key pattern. x shown
-x-ray) and the center of the linear region 8a. and,
If the deviation is present, the process proceeds to step m-38, in which the movement control means 64 activates the y-direction movement source 16, thus aligning the linear region 8a with sufficient precision to the center of the y-direction in the image being taken. position. After that, the process proceeds to step m-39, where the holding means 4 and the wafer 2 held therein are
It is determined whether a 90 degree rotation of has already been performed. If the above-mentioned 90 degree rotation has not been performed yet, the process proceeds to step m-40, and the movement control means 64
operates the θ direction drive source 18, and the holding means 4
And the wafer 2 held therein is rotated 90 degrees. Next, the process proceeds to step m-41, in which the movement control means 64 operates the x-direction drive source 14 and the y-direction drive source 16, and the data is stored in the RAM built in the central processing unit 36 (or in the key pattern memory 52). The above rotational displacement signal, that is, the sample wafer during key pattern memorization operation.
The holding means 4 and the wafer 2 held therein are moved in the x and y directions by an amount of movement corresponding to the amount of movement in the x and y directions after the 90 degree rotation. Thus, it is ensured that the same pattern as the key pattern of the specific areas 60L and 60R (and the sub-key pattern of the sub-specific areas 62L and 62R) shown in FIG. 5 is present in the image input to the imaging means 28. do. Thereafter, the process returns to step m-24. Therefore, the above step m-40
After returning to step m-24 via step m-41, in steps m-24 and m-36, the pattern is determined in one (or both) of the two images input to the imaging means 28. The matching type position detection means 54 detects the specific area 56L (or 5
6R), but it is determined whether or not the same pattern as the key pattern of the specific areas 60L and 60R is detected. As described above, the primary positioning and the secondary positioning are performed, and thus the wafer 2 is positioned sufficiently quickly and with sufficient precision to substantially eliminate mispositioning. Next, in step m-15, the primary positioning based on the detection of the relative position of the linear region 8a by the non-pattern matching type position detection means 38 is completed, and the pattern matching type position detection means 54
A case will be described in which it is determined that it is necessary to shift to secondary positioning based on the detection of the relative positions of the linear regions 8a and 8b. In this case, step m-15 to step m-42 (7th-C
Proceed to Figure). To explain with reference to FIG. 7-C, in the above step m-42, the imaging means 2
One of the two images input to the imaging means 8, for example, from the left light entrance aperture 30a of the enlarging optical means 26,
8, it is determined whether the pattern matching type position detection means 54 detects the same pattern as the key pattern of the specific area 56L (FIG. 4). In step m-42, if the pattern matching type position detection means 54 does not detect the same pattern as the key pattern, the start of the secondary positioning is stopped and the process returns to the primary positioning again.
That is, the process proceeds to step m-43, where the movement control means 6
4 operates the x-direction drive source 14 to move the holding means 4 and the wafer 2 held therein by a predetermined amount α in the x-direction. The predetermined amount α may be, for example, about 170 μm. Then, step m-
44, it is determined whether or not the non-pattern matching type position detection means 38 detects the linear region 8a in both of the two images input to the imaging means 28. In step m-44, if the non-pattern matching type position detection means 38 detects the linear region 8a in both of the two images,
Return to step m-42 above. On the other hand, step m-
44, the non-pattern matching position detection means 38 detects the linear region 8 in both of the two images.
If a is not detected, the process proceeds to step m-45, where the movement control means 64 operates the x-direction drive source 14 to move the holding means 4 and the wafer 2 held thereon by a predetermined amount α in the x-direction. In other words, it returns to the position before the movement by the predetermined amount α in step m-43. Thereafter, the process proceeds to step m-51, which will be described later. In the above step m-42, if the pattern matching type position detection means 54 detects the same pattern as the key pattern, the process proceeds to step m-46, and the center in the y direction (i.e., the fourth It is determined whether there is a shift or deviation between the line xx shown in the figure) and the center of the linear region 8a. If the above-mentioned deviation exists, the process proceeds to step m-47, where the movement control means 64 activates the y-direction movement source 16, so that the y-direction in the image of the linear region 8a is
Position it in the center of the direction with sufficient precision. After that, the process proceeds to step m-48, and the movement control means 64
activates the x-direction movement source 14 and the y-direction movement source 16, and moves the holding means 4 and the wafer 2 held therein to the key pattern of the specific area 56L (FIG. 4) and the sub-specific area 58L (fourth It is moved in the x and y directions by a distance β in the x direction and a distance γ in the y direction from the sub key pattern shown in FIG. Next, the process proceeds to step m-49, in which the pattern matching type position detection means 54 detects the sub-specific area 5 in one of the two images inputted to the imaging means 28.
It is determined whether or not the same pattern as the subkey pattern of 8L (FIG. 4) is detected. In step m-49, if the pattern matching type position detecting means 54 does not detect the same pattern as the sub-key pattern, the secondary positioning is stopped and the process returns to the primary positioning. That is, the process proceeds to step m-50, and the movement control means 64
actuates the x-direction drive source 14 and the y-direction drive source 16 to move the holding means 4 and the wafer 2 held thereon by a predetermined distance -β in the x direction and by a predetermined distance -γ in the y direction, thus Return to the position before the movement in the x direction and the movement in the y direction in step m-48. Next, the process proceeds to step m-51, where the movement control means 64 operates the y-direction drive source 16 to move the holding means 4 and the wafer 2 held therein by the distance d of the linear region 8a in the y-direction. . Thereafter, the process proceeds to step m-52, where it is determined whether the non-pattern matching type position detection means 38 detects the linear region 8a in both of the two images input to the image pickup means 28. In step m-52, if the non-pattern matching type position detection means 38 detects the linear region 8a in both images, the process returns to step m-42. On the other hand, step m-52
In both of the two images, the non-pattern matching type position detection means 38 detects the linear region 8a.
If not detected, the process proceeds to step m-53, where the movement control means 64 activates the x-direction drive source 14 to move the holding means 4 and the wafer 2 held thereon by about 170 μm in the x-direction. Move it a predetermined amount. Thereafter, the process proceeds to step m-54, where it is determined whether or not the non-pattern matching type position detection means 38 detects the linear region 8a in both of the two images inputted to the imaging means 28 again. . In step m-54, if the non-pattern matching type position detection means 38 detects the linear region 8a in both images, the process returns to step m-42. In step m-49, if the pattern matching type position detection means 54 detects the same pattern as the sub-key pattern, step m-55 is performed.
Then, it is confirmed whether or not there is a deviation, that is, a deviation, between the center of the image being captured in the y direction (i.e., the line xx shown in FIG. 4) and the center of the linear region 8a. . If the above-mentioned deviation exists, the process proceeds to step m-56, where the movement control means 64 activates the y-direction movement source 16, so that the linear region 8a is sufficiently moved to the center of the y-direction in the image being taken. Position precisely. Thereafter, the process proceeds to step m-57, where the other of the two images input to the imaging means 28, and therefore the enlarging optical means 2, is
It is also determined whether steps m-42 to m-56 described above have been performed regarding the image inputted to the imaging means 28 from the right light entrance aperture 30b of No. 6. If steps m-42 to m-56 described above have not been performed for the other of the two images, step m-42 is reached, and steps m-42 to m-56 described above are performed for the other of the two images. 56 will be carried out. On the other hand, if steps m-42 to m-56 described above have been performed with respect to the other of the two images, the process proceeds to step m-58 and the pattern mat is determined in each of the two images inputted to the imaging means 28. It is determined whether or not the positions of the linear regions 8a in the y direction detected by the ticking type position detection means 38 are aligned. Linear area 8a detected in each of the two images
If there is a difference in the y-direction position, the process proceeds to step m-59, and sufficiently precise θ-direction alignment is performed in the same manner as in step m-17 above. Thereafter, the process proceeds to step m-60, where it is determined whether there is a shift or deviation between the center of the image being captured in the y direction (i.e., the line xx shown in FIG. 4) and the center of the linear region 8a. It is confirmed whether or not. If the above-mentioned deviation exists, the process proceeds to step m-61, where the movement control means 64 activates the y-direction movement source 16, and thus the linear region 8
A is positioned with sufficient precision at the center of the image being captured in the y direction. After that, step m
-62, it is determined whether the holding means 4 and the wafer 2 held therein have been rotated by 90 degrees. If the 90 degree rotation has not yet been completed, the process proceeds to step m-63, where the control means 64 operates the θ-direction drive source 18 to rotate the holding means 4 and the wafer 2 held therein. Rotate it 90 degrees. Next, the process proceeds to step m-66, in which the holding means 4 and the wafer 2 held therein are moved by the amount of movement in the x and y directions based on the rotational displacement signal, in the same manner as in step m-41 described above. It is moved in the x direction and the y direction.
Thereafter, the process returns to step m-42. After returning to step m-42 via steps m-63 and m-64, in step m-42, the specific area 56L (or 56
R) but the above specific area 60L (or 60R)
It is determined whether or not the same pattern as the key pattern of the width specific area 62L (or 62R) is detected in step m-49. It is determined whether or not the pattern is detected. In the manner described above, the secondary positioning following the primary positioning is performed, and the wafer 2 is thus positioned sufficiently quickly and precisely at the desired position with virtually no mispositioning. Above, one specific example of the automatic precision alignment system configured according to the present invention has been described in detail with reference to the accompanying drawings, but the present invention is not limited to such specific example, and the scope of the present invention is Needless to say, various modifications and modifications are possible without departing from the above.

[Brief explanation of the drawing]

FIG. 1 is a simplified perspective view schematically showing a portion of a semiconductor wafer cutting apparatus equipped with an embodiment of an automatic precision alignment system constructed in accordance with the present invention. FIG. 2 is a partial plan view showing a portion of the surface of a typical wafer. FIG. 3 is a block diagram showing one embodiment of an automatic precision alignment system constructed in accordance with the present invention. 4 and 5 are simplified diagrams illustrating designated positions of a specific area and a specific width area on a sample wafer on a display screen by a display means. FIG. 6 is a flowchart showing an example of a pattern matching position detection procedure. FIG. 7-A, FIG. 7-B, and FIG. 7-C are flowcharts showing an example of an alignment procedure. 2... Semiconductor wafer, 4... Holding means, 8
(8a and 8b)... linear area, 12... moving means, 26... enlarging optical means, 28... imaging means, 32... A/D conversion unit, 34... image frame memory, 36... center Processing unit, 3
8...Non-pattern matching type position detection means, 4
0... Arithmetic processing means, 42... Linear area detection means, 50... Display means, 52... Key pattern memory, 54... Pattern matching type position detection means, 64... Movement control.

Claims (1)

[Claims] 1. There are a plurality of linear regions arranged in a grid on the surface, and a circuit pattern is applied to each of the plurality of rectangular regions partitioned by the linear regions. and an automatic precision positioning system for precisely positioning a semiconductor wafer, which is coarsely positioned using an orientation flat and supplied onto a holding means, at a desired position; and moving the holding means. a moving means for capturing an image of at least a portion of the surface of the semiconductor wafer held by the holding means;
an imaging means for outputting an analog signal indicating the density of a matrix array pixel; an A/D conversion means for converting the analog signal generated by the imaging means into a multivalued digital signal; and an A/D conversion means. an image frame memory for storing the multi-value digital signal generated by the image frame memory; and an arithmetic processing means for processing the multi-value digital signal stored in the image frame memory to generate a binary digital signal. , linear area detection means for detecting the relative position of the linear area based on the binary digital signal, and thus detecting the relative position of the linear area. a detection means; a key pattern memory for storing a key pattern corresponding to a specific area on the surface of the semiconductor wafer when the semiconductor wafer is in a predetermined position and a multivalued digital signal indicating the position of the key pattern; and the image frame memory. Detecting a pattern identical to the key pattern in the image captured by the imaging means based on the multi-value digital signal stored in the key pattern memory and the multi-value digital signal stored in the key pattern memory. a pattern matching type position detection means for detecting the relative position of the linear area; and the moving means in response to the detection of the relative position of the linear area by the non-pattern matching type position detection means. activating the wafer, thus performing primary positioning of the semiconductor wafer held by the holding means;
Thereafter, the movement means is actuated in accordance with the detection of the relative position of the linear area by the pattern matching type position detection means, and thus the movement for performing secondary positioning of the semiconductor wafer held by the holding means. An automatic precision positioning system comprising: a control means; 2. The key pattern memory includes at least one key pattern corresponding to at least one specific area on the surface when the semiconductor wafer is at the first predetermined position, and at least one key pattern when the semiconductor wafer is at the first predetermined position. at least one key pattern corresponding to at least one specific area on the surface when in a second predetermined position rotated 90 degrees relative to the surface; , performing positioning with respect to the first predetermined position, then rotating the holding means 90 degrees, and then performing positioning with respect to the second predetermined position. system. 3. An enlarging optical means is disposed between the surface of the semiconductor wafer and the imaging means, and an image of at least a portion of the surface of the semiconductor wafer is enlarged by a predetermined magnification by the enlarging optical means. An automatic precision positioning system according to claim 1 or 2, wherein the image is inputted to the imaging means. 4. The automatic precision alignment system according to claim 3, wherein the imaging means takes images of two mutually separated portions of the surface of the semiconductor wafer. 5. The movement control means performs automatic precision positioning according to claim 4, wherein in the primary positioning, the linear region exists in both of the two portions imaged by the imaging means. Combined system.