JPH0241508A - High performance positioning and measurement control system - Google Patents

Abstract

PURPOSE:To raise the positioning accuracy of an object to be positioned and to shorten the positioning time by forming a detection mark by an M array pattern and moving a placing table to a position where a mutual correlation function of detecting information and reference information becomes maximum. CONSTITUTION:A detection mark 13 is formed by an M array pattern, and at the time of comparing detecting information and reference information, a position where a mutual correlation function between the detecting information and the reference information becomes maximum is calculated, and a placing table 11 is moved to the position where the mutual correlation function becomes maximum. In such a way, an object to be positioned 12 can be positioned by non-contact, and also, as long as the detection mark 13 is detected, the moving direction of the object to be positioned 12 can be calculated and determined immediately. In this regard, even if a noise intrudes into the detection mark 13 or a detecting device 14, positioning of the object to be positioned 12 can be secured, therefore, the positioning accuracy and the positioning time of the object to be positioned 12 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (11) Object of the Invention [Field of Industrial Application] The present invention relates to a high-performance positioning measurement control system, and in particular to a detection system attached to an object to be positioned [Prior Art 1] In this type of positioning measurement control technology, a simple detection mark such as a crosshair is attached to the object to be positioned (for example, a semiconductor wafer), and the detection mark is detected by a detection means to obtain a result. It has been proposed to position an object by moving a table on which the object is placed in accordance with the result of comparing detected information and reference information.

[Problems to be solved] However, in conventional positioning measurement and control technology, the detection mark was a simple shape such as a crosshair, so (1) accurate positioning cannot be performed even if dust or oil is attached. There is a loud voice that can't be done, so let's do fii1 positioning 1M
It is necessary to make the boundary a clean room, and (iii
If the detection device does not correctly extract the intersection of the detection marks, the direction in which the i-position table should be moved cannot be immediately determined, which has the drawback that the working time associated with one position determination cannot be shortened.

Therefore, in order to eliminate these drawbacks, the present invention adopts an M-array pattern as a detection mark attached to an object to be positioned, and moves the mark toward a position where the cross-correlation function between detection information and reference information is maximized. It is an object of the present invention to provide a high-performance positioning measurement control unit system that moves an object to be positioned.

(2) Structure of the Invention [Means for Solving the Problem] The means for solving the problem provided by the present invention is as follows. The position of the object to be positioned is determined by moving the mounting table according to the result of comparing the detection information obtained by detecting the detection mark with the detection device and the reference information containing the information of the detection mark. In a high-performance positioning measurement and control system that executes a detection mark, the detection mark is formed by an M array pattern, and when comparing the detection information and the reference information, the cross-correlation function between the detection information and the reference information is A high-performance positioning measurement control system characterized by calculating the position where the cross-correlation function is maximum and moving the mounting table to the position where the cross-correlation function is maximum.

[Function] The high-performance positioning measurement control system according to the present invention attaches a detection mark to an object to be positioned placed on a mounting table, and detects the detection mark with a detection device to obtain an object. By moving the mounting table according to the result of comparing the detected information and the reference information containing the information of the detection mark, the object to be positioned can be positioned with high performance. In the position measurement control system, the detection mask is formed by an M array pattern, and when comparing the detection information and reference information, the position where the cross-correlation function between the detection information and the reference information is maximum is calculated. , by moving the mounting table to the position where the cross-correlation function is maximum, so that fi) there is no effect of positioning the object to be positioned without contact.

(ii) As long as the detection mark is detected, the moving direction of the object to be positioned is immediately calculated and determined; It functions to ensure positioning, and as a result, it functions to improve the positioning accuracy and positioning time of the object to be positioned.

[Example] Next, an example of the high-performance positioning measurement control system according to the present invention will be specifically described with reference to the accompanying drawings.

However, the examples described below are described to facilitate or accelerate the understanding of the explanation of the present invention, and are not described to limit the present invention.

FIG. 1 is a block diagram showing an embodiment of a high performance positioning measurement control system according to the present invention.

FIG. 2 is an operational explanatory diagram for explaining the operation of the embodiment shown in FIG.

3 and 4 are explanatory views for explaining a specific example of the embodiment shown in FIG. 1. FIG.

5 to 7 are explanatory diagrams for explaining another specific example of the embodiment of FIG. 1. FIG.

FIG. 8 is an explanatory diagram for explaining another specific example of the embodiment in FIG. 1.

First, the configuration of an embodiment of a high performance positioning measurement control system according to the present invention will be described in detail with reference to FIGS. 1 and 2.

IO is a high-performance positioning measurement control system according to the present invention, in which a detection mark 13 attached to the surface of an object to be positioned (for example, a semiconductor wafer 12) placed on a mounting table 11 is used. , a detection device 14 disposed near the mounting table 11 for detecting the detection mark 13 attached to the object to be positioned 12; and a detection mark 13 detected by the detection device 14. a detection information holding device 15 for temporarily storing and holding the contents of the detection mark 13 as the detection information S0; a reference information holding device 16 for storing and holding the contents of the detection mark 13 in advance as the standard "news S"; Detection information S connected to the detection information holding device 15 and reference information holding device 16 and held in the detection information holding device 15. Cross-correlation between the reference information Ss held in the reference information holding device 16. Arithmetic device 1 for calculating the position (io, mol) where the function ψ5D is maximum
7, and the calculated cross-correlation function φ3.7 connected to the arithmetic unit 17. is the maximum position (lo, mo
The table controller 18 is provided with a table control device 18 that moves the mounting table 11 toward the direction 1.

The detection marks 13 are arranged in a matrix (this is referred to as a reference M array M
- (j, kl) and a pattern (i.e., an optical pattern) created by coloring e.g. black and white correspondingly to O and l, respectively, or e.g. S and N poles; It is formed by a pattern (i.e. magnetic pattern) created by magnetizing (i = 1.2.3.
・, n; n≧31 and n is a natural number). Here, the optical pattern or magnetic pattern forming the detection mark 13 is referred to as a 1M array pattern. Therefore, if we consider the content described later, the M array pattern means that the period N is (2°-1)
The sequence (a,) in which there are (2°-1-1) zeros and 2n-1 l's in the same period is expressed as a matrix of N1 rows and N2 columns (NI N, = N ; N1 .Ni is a relatively prime number: N1=2"-1, N=211111"-t
; to +1ca=n) j (=i: modulo N+) row k
(=i; modulo Nx) is arranged in a column, and 0 and 1 are respectively labeled so as to be distinguishable by the detection device 14.

The M sequence (al) is the M sequence generation circuit 3 shown in FIG.
It refers to a sequence in which the period N generated by 0 is 2n-1, and is generally expressed as, and there are (2n-1-1) 0's and 2°-1 l's in the same period. do.

O and l of M series (a,) are +1 and -1 respectively
The autocorrelation function of the series (ml) created corresponding to is as follows.

Here, both M-sequence generation circuits are linear shift registers, each of which is 0 or l, and at least one of which is 1.
n shift registers 310.311.31! that store +on-+ and are connected in series to each other. , ・=
, 31. ,,, shift register 31oJL, 31g-
The feedback coefficient ha+Fl is connected to the output terminal of ``'-31n-+ and is 0 or l.
+, ha, h3. =·, hn feedback circuits 32°, 32. ．． 32°321. ..., 32
Il-+ is connected in series between the output end of the feedback circuit 32° and the input end of the shift register 31n-+, and the feedback circuits 32°, 32. .

32□, 32. , ..., 32□, fn-11 exclusive OR circuits 331.3 connected to the output terminals of 32□, respectively.
32.33333, .

The reference M array Ms(j, kl) is obtained by sequentially arranging the above M sequence (al) in 5 rows and columns so that j=i (modulo Nt) and k=i (modulo N2). Msl+, kl = [b Jk], where N, = 2"-1; N = 2"
”-1: k + ka = n and N = N, N.

(N1.Nl is a relatively prime number).

Therefore, the reference M array M, (j, kl is, for example, k + = k 2 = 2. N l = 3. N z
=5.

becomes.

The detection device 14 is constituted by an optical detection means (for example, a television camera) (when the il detection mark 13 is formed of an optical pattern, and (when the il detection mark 13 is formed of a magnetic pattern). It suffices if it is formed by the tn air detection means.

Furthermore, with reference to FIGS. 1 and 2, the operation of an embodiment of the high performance positioning measurement control system according to the present invention will be described in detail.

First, the M sequence (al
) are arranged in a matrix to form a reference M array Msfj,k
After creating l, color it black and white depending on whether al is 0 or 1 (optical pattern), or magnetize the S and N poles (i
A 1M array pattern was created using a 1M array pattern (hereinafter referred to as a
We will mainly explain the case of coloring black and white).

After that, the contents of the detection mark 13, that is, the reference M array M,
The contents of fj and kl are stored and held in the standard information holding device 16 as standard information SS.

At the same time, after attaching the detection mark 13 to the object 12 to be positioned, the object 12 to be positioned is placed at a predetermined position on the mounting table +1.

The mounting table 11 is controlled by the table control device 18.
The detection mark 13 is moved in the axial direction and the Y-axis direction, and the detection mark 13 can be detected by the detection device 14 .

The detection device 14 detects the detection mark 13, and converts the detection result, that is, the detection M array Mo1j'= ゛) into detection information S.
It is given as D to the detection information holding device 15.

The detection information holding device 15 stores the detection information S. That is, detection M array M. The contents of fj', ki are temporarily held by assigning 0 and l corresponding to black and white, respectively, and the cross-correlation function φ5of1. In order to calculate ml, 0 and l are converted to +1 and -1, respectively, and are provided to the subsequent arithmetic unit 17.

The calculation device 17 uses the reference information S3 given from the reference information holding device 16, that is, the reference M array Ms(j, kl) and the detection information S given from the detection information holding device 15.

That is, detection M array M. tj', ni') and the cross-correlation function ψso 11. Control = M s IJ, niMo1J, k
1- M s (j, kl M o (j+1. k
+ml is calculated.

The arithmetic device 17 calculates the position (to, mo) where the cross-correlation numbers Φ5oft, ml are maximum and provides it to the table control device 18.

The table control device 18 is placed a required distance in the X-axis direction and the Y-axis direction toward the position (1°, no) where the cross-correlation function φso fl, m) calculated by the calculation device 17 is maximum. Move the table 11.

When the mounting table 11 is moved by the table control device 18, the detection mark 1 is again moved by the detection device 14.
3 is detected.

The detection result of the detection mark 13 by the detection device 14 is as follows.

Processing is performed in the same manner as described above, and it is confirmed whether or not the positioning of the object 12 to be positioned has been correctly executed. That is, the arithmetic unit 17 checks whether the position (10, mJ) at which the cross-correlation function φ-(1, ml is maximum is (0, 01) or not.

If the positioning of the object 12 to be positioned is performed as desired and the cross-correlation function φ8° (1, ml is maximum at the position (0,01), then the positioning operation is completed.

On the other hand, the positioning of the object 12 to be positioned is not performed as desired, and the cross-correlation function φ90 (1, m) is
If the maximum value is not reached at 0,01, the above-described operation is repeated until the positioning is performed as desired.

As described above, according to the present invention, high-performance positioning measurement of the object 12 to be positioned can be performed.

In the above description, for convenience of explanation, the positioning information of the detection mark 13, that is, the entire M array pattern is simultaneously detected by the detection device 14 and the detection information S is obtained. The detected information S is stored in the detected information holding device 15, and the detected information S is stored in the arithmetic unit 17. All elements and reference information holding device 16
Although the mutual (0 function φ3゜(1, ml) is calculated at one time as a whole between all the elements of the reference information S held in Na(
Detection information S held in the detection information holding device 15 in the arithmetic unit 17. (i.e., detected partial information S op
) and its detection part report S. The reference information S has a size corresponding to the size of P. Reference partial information S s selected from
p and its reference partial information S sp to the reference llI information S
The information 541. were selected by changing their positions little by little (Oide Neighborhood News S).

The cross-correlation function φ5ut1. By allowing the calculation of ml, the present invention can shorten the time required to calculate the cross-correlation function ψ8° (1, ml), and in turn can significantly shorten the time required to position the member 12 to be positioned.

Further, in the present invention, the detection mark 13 is detected by the detection device 14.
Partial detection information S is obtained by simultaneously detecting a part of the positioning information, that is, the M array pattern. The partial detection information S is stored in the detection information holding device 15 as pp, and the partial detection information S is stored in the arithmetic unit 17. All elements of P and their partial detection information S. ,
A reference information holding device 1 having a size corresponding to the size of P.
Reference information S held in 6. The partial reference information S sp selected from the partial reference information S sp
The cross-correlation function φso il,m is sequentially selected while gradually changing the position of p over all the elements of the reference information S5.
While calculating l, the detection mark 13 by the detection device 14
The partial detection information S is obtained by moving the detection position of 1 little by little in the X direction or the Y direction. , the detection position of P is changed to cover all the elements of the detection mark 13, and the detection mark 1 is
The cross-correlation function ψ, over all elements of 3. (11 ml may also be calculated. As a result, the present invention can calculate the cross-correlation function φ
The time required to calculate 5oft, ml can be shortened, and the time required to position the member 12 to be positioned can be significantly shortened.

Furthermore, in the above description, a television camera is used as the detection device 14, one element of the optical pattern used as the detection mark 13 is associated with a plurality of pixels of the television camera, and one element of the optical pattern used as the detection mark 13 is associated with a plurality of pixels of the television camera. Storage area of detection information holding device 15 and reference information holding device 1
6 storage areas are made to correspond l to l, and a cross-correlation function ψ1lDI1. The cross-correlation function ψ5o11 is calculated by sampling ml for each plurality of pixels of the television camera. ml
Find the position (lo', mo'l that maximizes
'l ψso 11. Calculate ml for all pixels of the TV camera! -1 cross-correlation function φ5o (1, ml) may be determined as the maximum position flu1mol.Thereby, the present invention can shorten the calculation time of the cross-correlation function φ, fl, ml, and furthermore, the position flu1mol can be The time required for positioning 12 can be significantly shortened.

Furthermore, the focal pressure of the detection device 14! Although the description has been made assuming that the detection mark 13 is located at ff1 (i.e., the position with the highest resolution), the present invention is not limited to this, and the detection mark 13 is located at a position distant from the focal length of the detection device 14 (i.e., The detection mark 13 may be positioned at a position where the resolution is relatively low), so that when the detection mark 13 is detected by the detection device 14, the elements of the M array pattern of the detection mark 13 are averaged in parallel. Can perform processing. Therefore, the present invention can shorten the time required to calculate the cross-correlation functions φ5ott and ml, and in turn can significantly shorten the time required to position the member 12 to be positioned.

In addition, in order to better understand the structure and operation of one embodiment of the high-performance position measurement control system according to the present invention, specific numerical values will be given and explained.

The M sequence (a,) generated by the JftfLLL M sequence generation circuit is 1.1.0.0. l, 1.0, 0.1.1.0.0゜1
．． 1.0, therefore the reference M array Mstj,k
It was said that it was l.

The detection mark 13 is located at 0 of the reference M array M stj, kl.
An optical pattern was formed by coloring 1 and 1 black and white, respectively, and the shape was as shown in FIG. In FIG. 3, the boundaries of the elements of the optical pattern are displayed as solid lines, but this is adopted to clearly indicate the elements, and is removed in the actual detection mark 13, and is simply It was painted in black and white (the same is true in Figure 4).

The contents of the detection mark 13 shown in FIG. 3 were stored and held in the reference information holding device 16 with black and white as O and l, respectively. In other words, the reference information holding device +
In addition, the detection mark 13 shown in FIG.
It was attached to the surface of No. 2 by an appropriate means. The member 12 to be positioned was then placed on the placement table 11 and subjected to one extraction by the detection device 14.

Detection information S is obtained when the detection device 14 detects the detection mark 13 i-. That is, the detection M array M, , +j, kl is located at the reference position f1. as shown in FIG. ml = 10.01
Offset position 11. AL located at ml = f2.11
was alive.

Detection information Stl, that is, detection M array M. (j', kl are 0 for black and white, respectively, in the detection information holding device 15.
and l.

After that, the detection information S. That is, t, detection M array Mofj'
, the contents of 'l make O and l +1 and -, respectively.
xf device 1
given to 7. Also, the reference information, that is, the reference M array Ms
The contents of fj and kl are the groups obtained by converting O and l into ■ α = Table 1 +1 and -l, respectively! ! The information is given to the arithmetic unit 17 as information Madnox.

As a result, in the arithmetic unit 17, by the cross-correlation function or more,
High-quality positioning measurement of the object 12 to be positioned could be performed.

was calculated.

Cross-correlation function φ5of1. ml was as shown in Table 1 corresponding to the value of (1, ml).

As is clear from Table 1, the cross-correlation function ψ5oft,
ml was maximum at the deflection position fto, mol = 12.11.

Therefore, the calculation result from the arithmetic unit 17 is the deviation position f.
lo, mol = (2, II) is given to the table control device 18, so that the table control device 18 biases the loading table ■ to the position flo, mol = t2
, l) in the X-axis direction and the Y-axis direction.

``1 plate blood λL M sequence generation circuit Group 1! created by arranging the M sequence (a,) generated by the court according to the above rules! M array Ms
The detection mark 13, which was formed as a graphic pattern by coloring O and 1 of fj and kl black and white, respectively, had a shape as shown in FIG. Fifth
In the figure, the boundaries of the elements of the optical button are shown as solid lines, but this is adopted to clearly indicate the elements, and is removed in the actual detection mark 13, and is simply shown in black. It was painted in white (6th
(Same in figure).

The contents of the detection mark 13 shown in FIG. 5 were stored and held in the reference information holding device 16 with black and white as 0 and 1, respectively. That is, the reference information holding device 1
6, the base IM array ~.1, Ij, kl was stored as reference information Sg. Here, the reference information holding device 16 has a storage area formed in a ratio of 1:1 to the pixels of the television camera used as the detection device 14, and the pixels are used as optical patterns used as the detection marks 13. There was a 4-to-1 correspondence to one element of .

Further, the detection mark 13 shown in FIG.
20 surfaces by appropriate means. The member 12 to be positioned was then placed on the placement table 11 and subjected to detection by the detection device 14.

When the detection device 14 detects the detection mark 13, the detection signal S0, that is, the detection M array Mofj', 'l is the sixth
As shown in the figure, the base 4 positions fl, ml = io, ol
An IL was born, located at a displacement position 1], ml = flO99).

Detection information S. That is, detection M array M. fj', ni'1 sets black and white to 0 in the detection information holding device 15, respectively.
and l. Detection information holding device 1
In No. 5, the storage areas were formed in a ratio of 1 to 1 with respect to the pixels of the television camera used as the detection device 14.

After that, the detection information S0, that is, the detection M array Mofj'
, the contents of 'l are 0 and l respectively +1 and -
The detected information matrix mo(j, k) converted to 1 was given to the arithmetic unit 17. The contents of the reference information, that is, the reference M array M-fj, kl, are the reference information matrix ms obtained by converting 0 and l to +1 and -1, respectively.
It is given to the arithmetic unit 17 as O, kl.

As a result, the arithmetic unit 17 calculated the cross-correlation function. At this time, the cross-correlation function φ5o(1, ml does not necessarily have to be calculated for each pixel of the television camera used as the detection device 14, but may be calculated for every 4 pixels, for example. That is, ?i t' Sampling every pixel and calculating the position flo', m, I that maximizes the cross-correlation relationship φ5of1.ml, then calculate for all pixels near the position [o', mo'l and calculate the mutual correlation. The position (lo,
You can also find mol. This gives the cross-correlation function φ
5of1. The time required to calculate ml can be shortened.

The cross-correlation function φ80 (1, mj is as shown in FIG. 7 corresponding to the values of fl, ml). position +1o, mol = ilo
, it reached its maximum when it was 9+.

Therefore, the calculation result from the calculation device 17, that is, the bias position fl
o, mol: (10, 91 is the table control device 18
, the table controller 18 shifts the loading table 11 to a biased position fto, mol ”ilO
, 91 in the X-axis direction and the Y-axis direction.

As described above, the high 1-it-power positioning measurement of the object 12 to be positioned could be performed.

In Example 2, the detection mark shown in FIG. 5] 3-7
The cross-correlation function φ is indicated by filling in 0% with white. (The maximum value of 1, ml decreased as shown in Figure 8, but as is clear from comparison with Figure 7, its position fio', mo'l has not changed, and the position There was no problem in positioning the deciding object 12.

In Example 2, it has been confirmed that even if about 80% of the detection mark 13 shown in FIG. 5 is filled with white, there is no problem in positioning the object 12 to be positioned according to the present invention.

(3) Effects of the Invention As is clear from the above, the high-performance positioning device 11 control system according to the present invention attaches detection marks to the object to be positioned placed on the placement table. By moving the mounting table according to the result of comparing the detection information obtained by detecting the detection mark with the detection device and the reference information containing the information of the detection mark,
In a high-performance positioning measurement control system that performs positioning of an object to be positioned, the detection mark is formed by an M array pattern, and when comparing the detected information and the reference information, the detection mark is formed by the M array pattern. The position where the cross-correlation function between the positions is maximum is calculated, and the mounting table is moved to the position where the cross-correlation function is maximum. In addition, as long as the fiill detection mark is detected, the moving direction of the object to be positioned can be immediately calculated and determined. As a result, (iv) the positioning accuracy and positioning time of the object to be positioned can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the high-performance positioning measurement control system according to the present invention, FIG. 2 is an operation explanatory diagram for explaining the operation of the embodiment in FIG. 1, and FIGS. The figures are explanatory diagrams for explaining a specific example of the embodiment shown in FIG. 1, FIGS. The figure is an explanatory view for explaining another specific example of the embodiment shown in FIG. 1. . ...Feed bank circuit...Exclusive OR circuit lO......High performance positioning measurement control system

Claims (5)

[Claims] (1) A detection mark is attached to the object to be positioned placed on the mounting table, and the content is the detection information obtained by detecting the detection mark with a detection device and the information possessed by the detection mark. In a high-performance positioning measurement control system that positions an object to be positioned by moving a mounting table in accordance with the results of comparing reference information with each other, a detection mark is formed by an M array pattern. When comparing detected information and reference information, the position where the cross-correlation function between the detected information and the reference information is maximum is calculated, and the mounting table is moved to the position where the cross-correlation function is maximum. A high-performance positioning measurement control system that is characterized by: (2) The high-performance positioning measurement control system according to claim (1), wherein the M array pattern is an optical pattern formed corresponding to the M array. (3) The l elements of the M array pattern are made to correspond to multiple pixels of the detection device, and when calculating the position where the cross-correlation function is maximum, the detection information corresponding to each of the multiple pixels of the detection device is sampled. A high-performance positioning measurement and control system according to claim (2), characterized in that the positioning is performed by using a device. (4) One element of the M array pattern is made to correspond to multiple pixels of the detection device, and when calculating the position where the cross-correlation function is maximum, sampling is performed from among the detection information corresponding to each of the multiple pixels of the detection device. After calculating the maximum position using the calculated values, positioning is performed by precisely calculating the maximum position using all of the detection information corresponding to each of the plurality of pixels of the detection device. A high-performance positioning measurement control system according to claim (2). (5) The high-performance positioning measurement control system according to claim (1), wherein the M array pattern is a magnetic pattern formed corresponding to the M array.