JPH03218619A - Aligner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an exposure apparatus.

(Prior art and problems to be solved by the invention) Generally,
A lithography process in manufacturing a semiconductor device includes five steps: a surface treatment step, a resist coating step, an exposure step, a development step, and an etching step. In these steps, vacuum devices such as projection exposure devices and etching devices are used. Such vacuum devices generally have a mechanical mechanism that clamps the wafer with a member, and uses the mechanical mechanism to transport or fix the wafer to a stage.

However, if the post-treatment in the resist coating process is insufficient, resist may remain on the peripheral edge of the semiconductor wafer. In such a case, if the wafer is clamped by a mechanical mechanism, the residual resist will peel off from the wafer due to contact with the clamping member, and this will turn into foreign matter such as dust, reducing the cleanliness of the clean room.

Under these circumstances, Japanese Patent Publication No. 53-37706 and Japanese Unexamined Patent Application Publication No. 55-12 have been proposed as means for preventing the generation of foreign matter (dust).
750, JP-A-58-58731, JP-A-58-191434, JP-A-60-94660, JP-A-61-111151, JP-A-61-
Publication No. 121333 and JP-A-61-184824
There is a side rinse technology disclosed in the publication.

In addition, as a means to prevent the generation of foreign matter (dust), JP-A-58
-200537 Publication, Japanese Utility Model Application Publication No. 58-81932, Japanese Utility Model Application Publication No. 59-67930, Japanese Unexamined Utility Model Publication No. 1987-110
118, JP 60-121719, JP 60-189937, and JP 61-23
There is a backside cleaning technique disclosed in Japanese Patent No. 9625. (Note: If you know the relevant U.S. patent number or U.S. application number of any of the above prior documents, please enter them. The examiner may request translations of these prior documents. (If there are any unnecessary ones, please delete them. The same applies to the prior documents listed below.) However, in each of the above resist removal techniques,
Since the wafer is processed while being rotated, resist tends to remain on the orientation flat (0.F.) portion of the wafer, and there is a risk that this will peel off. To solve this problem, if the resist removal range is expanded, wafer 1
The number of semiconductor devices per chip decreases, resulting in lower product yields. In addition, the resist bulges at the boundary between the resist removed area and the non-removed area, and when using a device that targets multiple points other than the exposed area for focusing, there is a drawback that defocus occurs at this resist bulge. Therefore, in order to eliminate the above-mentioned inconvenience, 0. F. O.O. F. The technology applied to
It is disclosed in Publication No. 9135. According to this technique, a porous member containing a solvent is brought into contact with the peripheral edge of the wafer to remove the resist. However, even with the above techniques, problems such as out-of-focus during exposure cannot be solved.

In order to eliminate the focus blur during exposure, an exposure technique for removing the resist layer at the periphery of the wafer in an annular manner is disclosed in Japanese Patent Laid-Open Nos. 58-159535, 61-73330, and Japanese Patent Application Laid-Open No. 61-73330. It is disclosed in Publication No. 60-94661.

According to this technique, a wafer is attracted by a chuck whose rotating shaft is equipped with a cam having the same shape as the contour of the semiconductor wafer. Next, the wafer is rotated with the exposure light source guided by the optical fiber following the cam, and the peripheral edge of the wafer is exposed.

However, the above-mentioned copying cam type exposure apparatus has the disadvantage that the cam must be replaced depending on the type of wafer, which hinders automation (FA) of the exposure process. Another drawback is that the cam wears out and generates dust.

In addition, in the above exposure technique, in order to avoid peeling of the resist from the mutual contact portion between the mechanical arm and the wafer when the semiconductor wafer is transferred, the resist at the mutual contact portion is removed in advance.

According to this method, since the resist is removed by exposing the entire external part of the wafer including the mutual contact portions, there is a drawback that even the resist at the periphery of the wafer that is not in direct contact with the mechanical arm is removed unnecessarily.

Furthermore, in the above exposure technology, since the ultraviolet light is guided onto the wafer using an optical fiber and moved over the wafer, vibrations of the drive system are transmitted to the fiber, making it impossible to obtain a sharp exposed image. .

Furthermore, the current throughput of reading methods for CCD line sensors is low.

Furthermore, since the adjustment range of the exposure amount per unit time is small, bubbling of the resist may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus that can prevent the generation of foreign matter such as dust and also prevent out-of-focus during exposure.

Furthermore, it is an object of the present invention to provide an exposure apparatus that can perform exposure processing on wafers at a high yield without being affected by the contour shape of, for example, the peripheral edge of a semiconductor wafer.

(Means for Solving Problem W) In order to achieve the above object, the present invention provides a mounting table on which an object to be processed is provided, a rotation mechanism for rotating this mounting table, and a rotation mechanism that faces the mounting surface of the mounting table. a light irradiation body provided as a light irradiation body, a movable mechanism that reciprocates the light irradiation body in the direction of the center of the placement surface, an exposure range input means for inputting a range of the object to be processed, and the inputted exposure exposure range storage means for storing a range; reference position detection means for detecting a reference position of the object to be processed; relative position detection means for detecting a relative positional relationship between the reference position and the light irradiation body; movable mechanism control means for controlling the movable mechanism in accordance with the relative position and the exposure range; and light irradiated from the light irradiation body onto the processing target plate in accordance with the relative position and the exposure range. and a light amount control means for controlling the amount of light.

(Function) In the present invention, the reference position detection means detects a predetermined position of the plate to be processed, the relative position detection means compares the relative positional relationship between the reference position and the light irradiation body, and the movable mechanism control means The movable mechanism is controlled in accordance with the relative position and the input exposure range, and the light amount control means irradiates the plate from the light irradiator in accordance with the relative position and the exposure range. The amount of light emitted is controlled.

(Embodiments) Various embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, an example will be described in which an exposure apparatus is used in a site rinsing process and a backside cleaning process. As shown in FIG. 1, the exposure apparatus 10 includes an exposure system 10a, a control system 10b, and a stage system 10c.

The exposure system 10a has a drive mechanism 23. As shown in FIG. 2, the drive mechanism 23 is for moving the slider mechanism 22 in a horizontal plane. A light irradiator 21 is attached to the slider mechanism 22 .

As shown in FIG. 1, the drive mechanism 23 includes a drive circuit 37 of the control system 10b, a storage element 35, and a stage rotation drive circuit 3.
3 to the stage rotation mechanism 11 of the stage system 10c. On the other hand, the drive mechanism 23 is connected to the optical sensor 17 of the stage system 10c via a drive circuit 37, a memory element 35, and a sensor output processing circuit 34. Further, a sensor drive circuit 31 connected to the storage element 35 and the reference signal generator 30 is connected to a drive mechanism (not shown) that moves the support member of the optical sensor 17.

Note that the sensor drive circuit 31 has a function of forming a drive pulse using a clock signal generated from the reference signal generator 30. On the other hand, the stage rotation drive circuit 33 has a function of forming a drive pulse using a pulse obtained by frequency-dividing the clock signal of the reference signal generator 3o by the frequency divider 32.

In addition, the output processing circuit 34 compares the output signal level with a set threshold value every pulse of scanning of the optical sensor 17, thereby detecting the peripheral portion (0.F. portion) of the wafer 13. including).

As shown in FIG. 2, the stage rotation mechanism 1l has a stepping motor (not shown). This stepping motor is connected so that its rotation angle can be pulse-controlled by a command signal from a circuit 33. The rotation mechanism 11 is
It is connected to the stage 12 via a shaft 11a. A semiconductor wafer W having an orientation flat is placed on the stage 12 .

As shown in FIG. 3, a hollow portion 14 is formed in the stage 12, and this hollow portion 14 communicates with a suction port of a vacuum pump (not shown). The end face detection means 18 is the stage 1
It is provided near the peripheral edge of the wafer W on the wafer W2. The end face detection means 18 is for detecting the exposure reference position of the wafer W, and includes a pack light 15, a lens 16, and an optical sensor 17.

The backlight 15 faces the lens l6 with the periphery of the wafer W in between. The optical sensor 17 is provided further above the lens l6.

The optical sensor 17 is a solid-state image sensor, such as a CCD (Cha
It is composed of a one-dimensional sensor using an RGE Couple Device).

As shown in FIG. 2, the light irradiator 2l faces the peripheral edge of the wafer W placed on the stage 12. As shown in FIG. The light irradiator 2l is guided near the peripheral edge of the wafer W by a slider mechanism 22. That is, when the slider mechanism 22 is reciprocated by the drive mechanism 23, the light irradiator 2l moves in and out of the area above the wafer W.

As shown in FIG. 4, the light irradiator 2l has an aperture 104 and first and second lenses 105 and 106. These are stored in a container 102. The end of the light conduit 20 is connected to the container 102 through the upper opening of the container 102 . The light conduit 20 is made of optical fiber or liquid fiber (trademark of Company Y, ULTLA FINE TECHNOLOGYJ).
) is made of. The proximal end of the light conduit 20 is connected to a UV light source (not shown).

The UV light introduced into the container 102 by the light conduit 20 is
It passes through the hole 103 of the diaphragm 104. The hole 10 is formed into a square or rectangle. First and second lenses 105 and 106 are arranged on the optical path passing through the aperture 104, so that the UV light beam is focused on the peripheral surface of the wafer W. The reflected light from the wafer W is transmitted to the light irradiator 2.
1, a ring skirt 107 is attached to the lower part of the light irradiator 21. Note that the inner wall surface of the container 102 of the light irradiator 21 is preferably black.

The slider mechanism 22 has a pole screw (not shown). Drive mechanism 23 via this pole screw
Driving force is transmitted from the slider mechanism 22 to the slider mechanism 22. The drive mechanism 23 is driven by a stepping motor. Note that the exposure system 10a may be provided at the same position as the end face detection means l8. By providing both at the same position, it can be expected that throughput will be improved.

The operations of these end face detection means 18 and exposure system 10a are as follows.
It is controlled by transmitting and receiving predetermined command signals and detection signals through the control system 10b.

Next, with reference to FIGS. 5 to 15 and Table 1, a case in which a semiconductor wafer W is subjected to exposure processing using the above-mentioned exposure apparatus will be described. (I) First, a recipe necessary for exposing various semiconductor wafers W is input into the input section 36 in advance. Inputting a recipe depends on manual input using keys on a keyboard, data reading input using a flat sensor using a surface sensor, and the like.

Recipe parameters include ``pass-through specification,'' ``lower limit of illuminance,'' ``primary flat length,'' and ``sequence parameter.''

“Pass-through designation” designates whether or not exposure processing is to be performed. For example, exposure processing No. Processes 1 to 5 are conditions that do not specify pass-through, and exposure processing N
O. Process 6 is a condition for specifying pass-through.

The "lower limit of illuminance" is the minimum illuminance required to start the exposure process, and the wafer W is not taken in until the illuminance of the light irradiator 2l satisfies the set lower limit. For example, the setting range is 0 to 9900 mV, the setting range is 100 mW, and the exposure processing No. In each of the processes 1 to 5, the lower limit of illumination/intensity is set to 1000 mW.

In addition, exposure processing NO. There is no need to set this in the process of step 6.

"Primary flat length" is the O. F. This is the length of the outer end of the section. Based on this flat length, 0. F
．． The center of the outer edge of the part is detected as the reference position. For example, the setting range is 10 to 150mm, and the setting unit is 1mm.
and exposure processing NO. In each of exposure processes 1 to 6, the primary flat length is set to 551 Im. however,
No setting is required for one-round exposure (exposure with an exposure range angle of 360 degrees).

Next, the [sequence parameter] will be explained.

"Sequence parameters" are for setting the exposure area, and specifically, "exposure start orientation", "exposure range angle", "exposure width", and "one round equivalent exposure" shown in the horizontal column of Table 1. The combination of each parameter of time j is set as a sequence unit, and multiple sequence settings can be made in one exposure process.The "exposure start orientation" is 0. F. The center point of the section is set as the reference position, and the azimuth angle is set in the counterclockwise direction in FIGS. 10 to 14. The settable range is 0 to 359 degrees, and the setting unit is 1 degree. This setting is ignored when performing a one-round exposure.

The "exposure range angle" is set as an angle between the exposure start azimuth angle and the exposure end azimuth angle. The settable range is 0 to 360°, and the setting unit is 1°. If this is set to 360@, it is treated as a one-round exposure and the exposure start orientation is ignored.

The "exposure width" is used to set the position of the wafer W to be exposed from the periphery toward the center. The settable range is 0 to 35.0 mm, and the setting unit is 0.1 mm.

The "exposure time equivalent to one round" is used to set the rotational speed of the wafer W during exposure processing in terms of time.

The set time is the converted time when the wafer W makes one revolution. For example, if the exposure range angle is 180° and the exposure time is set to 20 seconds, one rotation of the wafer W.
80° range for 10 seconds (= 20 x 180/3
60) is exposed.

(II) As mentioned above, a predetermined recipe is input to the input section 3 in advance.
When input is set to 6, exposure device I! Turn on switch 10 to start the exposure process. A transport mechanism (not shown) carries the semiconductor wafer W to the stage system 10c (ST
EP71), after positioning the wafer W, the stage l
2 (STEP 72).

A resist having a predetermined thickness is applied to the surface of the wafer W. When the wafer W is placed on the stage 12, the wafer W
is vacuum-adsorbed to the stainless steel 12.

(m) The exposure system 10a and the stage system 10e are sequentially controlled based on command signals from the control system 10b. That is, a signal is sent from the circuit 33 to the mechanism l1 to rotate the stage l2 at a speed of 1 to 6 rpm (STEP 73).

(IV) Synchronizing with each step of the stepping motor of the mechanism 11, the optical sensor (COD image sensor) 17 of the end face detection section 18 is scanned. By this scanning, the rewafer W
The position of the edge is detected (STEP 74).

Here, the output signal from the optical sensor 17 is obtained as a voltage level difference proportional to the position from the edge of the wafer W. Based on this output signal, the circuit 34 calculates the distance of the exposure area from the edge of the wafer W to a predetermined position.

In this case, the contrast of the output signal of the optical sensor 17 increases due to the irradiation light from the backlight 15. The backlight 15 may be a one-dimensionally arranged LCD or a surface light source. Further, when the sensitivity of the optical sensor 17 is high, it is not necessary to turn on the backlight 15.

Further, the lens 16 is for the detection width of the optical sensor 17. Therefore, if the size difference between the wafers W to be processed is not so large, it is not necessarily necessary to use it.

Here, it is desirable to use a COD image sensor, which is a solid-state image sensor, as the optical sensor l7. The reason is C.
This is because the CD image sensor has high sensitivity even when the object to be processed is a light-transmitting object such as glass, and can detect even slight differences in light amount.

In the case of one-round exposure, the processing time can be shortened by detecting the first half-circle and then performing the detection of the remaining half-circle in parallel with the first half-circle exposure process.

(V) Next, the detection information regarding the edge position of the wafer W is stored in the storage element 35 of the control system 10b (S
TEP75). Based on this stored information and a predetermined recipe, the processing width of exposure necessary for side rinsing or back cleaning is determined. F. The center point (reference point) of the edge is calculated (STEP 76).

Based on this calculation result, the light irradiation position by the exposure system 10a is controlled. That is, the light guide tube 2 is connected to the light irradiator 21.
A light beam is irradiated from a light source (not shown) through 0.

For example, a mercury lamp or a xenon lamp is used as the light source for exposure.

The irradiation position of the bright light beam is determined based on information stored in the storage element 35. A signal calculating a desired area to be exposed for side rinsing or back surface cleaning of the wafer W is sent from the memory element 35 to the circuit 37. Based on this signal, the operations of the slider mechanism 22 and drive mechanism 23 are controlled as described below.

(VI) First, the stage 12 is rotated by a predetermined angle and stopped at a position where the wafer W is in a predetermined exposure start direction with respect to the light irradiator 21 (STEP 77).

Next, the light irradiator 21 is moved to a predetermined position according to the exposure width (STEP 78).

Next, while rotating the stage 12 at a predetermined speed, a predetermined amount of light is irradiated from the light irradiator 21 (STEP 79).

As a result, a desired area of the wafer W is exposed. In this case, a shutter may be provided on the optical path from the light irradiator 21 to adjust the amount of irradiated light. For example, the wafer W is fixed on the stage 12 and exposed continuously at each step by a step motor. As a result, the 0. F. Also for parts where you specify the area or exposure angle. It can be exposed to light in the same way as other wafer peripheral parts.

In addition, when performing multiple exposures. STEP 79 to STE
Return to P77 and execute STEP77 to STEP79 again.

The state of irradiation of the exposure light onto the peripheral portion of the wafer W will be described in detail with reference to FIGS. 6 to 9.

The light beam 103 is . The light is focused into a rectangular shape by the aperture 104 of the light irradiator 21.

As shown in FIG. 6, the light beam 107 may be irradiated only on the peripheral edge of the wafer W, but preferably, as shown in FIG. irradiate. Note that in FIGS. 6 and 7, the edge portion of the wafer W is shown protruding in a triangular shape in order to exaggerate E.

As shown in FIG. 8, the image formation shape of the light beam 107 may be rectangular, but preferably each corner of the rectangle is smooth as shown in FIG. Furthermore, the image formation shape of the light beam 107 may be an elliptical spot. The reason for this is that when the angle of some of the corners of the irradiation area becomes narrower, the illuminance of the light at each corner becomes lower, and uniform peripheral exposure is inhibited.

(■) When the desired exposure processing up to STEP 79 is completed, the wafer W is transferred to the exposure apparatus 10 by a transport mechanism (not shown).
(STEP 80). After being carried out, the wafer W is developed and cleaned, and the resist film is partially removed to obtain a predetermined pattern.

Next, while referring to Figures 10 to 15 and Table 1,
A case where the wafer W is exposed under various conditions will be described.

The wafer W shown in FIG. 10 has the exposure treatment No. in Table 1.
It was exposed under conditions corresponding to 1. In the figure, a shaded area 13a indicates an exposure area where the peripheral edge of the wafer W is exposed at 360 degrees with a width of 4 mm.

The wafer W shown in FIG. 11 has exposure processing No. in Table 1,
It was exposed under conditions corresponding to 2. In the figure, hatched areas 13a and 13b indicate the peripheral edge of the wafer W with a width of 4 mm and a width of 8 mm, respectively, at 360 degrees.

The wafer W shown in FIG.
It was exposed under conditions corresponding to 3. In the figure, a shaded area 13a indicates an exposure area where the exposure starting direction is 90'' and the peripheral edge of the wafer W is partially exposed by 30 degrees with a width of 4IIIm.

The wafer W shown in FIG. 13 has the exposure treatment No. in Table 1.
This image was exposed under conditions corresponding to 4. In the figure, a shaded area 13a indicates an exposure area where the peripheral edge of the wafer W is exposed for 360'' with a width of 4+a+a, and a shaded area 13b indicates an exposure area where the circumferential edge of the wafer W is partially exposed by 30 degrees with a width of 8mm. The portion 13c extends around the periphery of the wafer W with a width of 6 and 3.
Shows the exposed area partially exposed by 0'. The wafer W shown in FIG. 14 has the exposure treatment No. in Table 1. It was exposed under conditions corresponding to 5. In the figure, the shaded area 13a, 1
3b and 13c, the exposure starting direction is 45°,
165'' and 285'', respectively, and show the exposure areas in which the periphery of the wafer W was partially exposed by 30'' with a width of 4 m+a. The wafer W shown in FIG.
The condition corresponding to No. 6 is shown, that is, the exposure process is omitted due to pass-through designation.

As a result of developing and cleaning each of the wafers W shown in FIGS. 10 to 14, no local swelling of the resist film occurred. Therefore, it was possible to prevent the occurrence of so-called defocusing, and it was possible to easily form a clear fine pattern on the semiconductor wafer W.

Note that by using the identification mark M of the wafer W shown in FIGS. 12 and 15, 0. F. The exposure area may be set by selecting the center point of the identification mark M as the reference point instead of the sensor point of the section. Further, in the above embodiment, the optical sensor 1 of the end face detection means 18
Although a CCD image sensor is used in 7, any sensor may be used as long as it can detect the peripheral edge of the wafer W in a non-contact manner.

Further, in the above embodiment, a case has been described in which a pole screw is used for the slider mechanism 22, but the present invention is not limited to this, and a mechanism having a timing belt, a linear motor, etc. may be adopted.

Furthermore, as shown in FIG. 16, the slider mechanism 42 and the drive mechanism 43 may be provided at a position lower than the wafer W.
In this way, each mechanism 42. The dust generated in step 43 becomes difficult to adhere to the wafer W. Moreover, the cleanliness of the entire apparatus can be increased.

Furthermore, in the above embodiment, a semiconductor wafer was used as the object to be exposed. However, the object to be processed is not limited to this, and a liquid crystal display (LCD) coated with a film is used as the object to be exposed.
) Square glass substrates such as devices may be processed. Further, in the above embodiment, the case where the surface of the semiconductor wafer is processed is explained, but it is sufficient to treat the peripheral part.
The back side can be treated in the same way.

Further, in the above embodiment, the peripheral edge of the semiconductor wafer was exposed with the rotating shaft fixed, but the position of the rotating shaft may be adjusted based on the data information of the wafer edge.

Further, in the above embodiment, a case has been described in which exposure processing is performed with the illuminance of the exposure light constant, but it is also possible to deal with cases where the illuminance is lower than the initial level of use. This is what is called cumulative exposure, and can be realized by providing the control system with a function to compensate for the decrease in illuminance by extending the exposure time.

〔Effect of the invention〕

According to the exposure apparatus of the present invention, generation of foreign substances other than resist can be prevented. Further, it is possible to prevent out of focus.

Furthermore, only desired portions of the plate to be processed can be selectively exposed to light. In addition, exposure processing can be performed at a high yield without being affected by the contour shape of the plate to be processed.

The apparatus of the present invention has various effects as described above, improves the reliability of the entire exposure process, and can improve throughput.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining an embodiment of an exposure apparatus according to the present invention, FIG. 2 is a perspective view for explaining the optical system of FIG. 1, and FIG. 4 is a diagram schematically showing the optical system of the light irradiator in FIG. 3, and FIG. 5 is a process diagram showing the exposure process in FIG. 1. 6 and 7 are side views schematically showing the periphery of the semiconductor wafer when viewed from the side, and FIGS. , 6 and 7, plan views schematically showing the peripheral edge of a semiconductor wafer viewed from above, and FIGS. FIG. 16 is a plan view for explaining a semiconductor wafer subjected to exposure processing, and FIG. 16 is a perspective view showing the main parts of an exposure apparatus for explaining another embodiment of FIG. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 14 Figure 11

Claims (3)

[Claims] (1) A mounting table on which the object to be processed is provided, a rotation mechanism for rotating this mounting table, a light irradiation body provided opposite to the mounting surface of the said mounting table, and a light irradiation body provided on said mounting base. a movable mechanism that reciprocates in the direction of the center of the surface; an exposure range input device that inputs the exposure range of the object to be processed; an exposure range storage device that stores the input exposure range; and a reference position of the object to be processed. a reference position detection means for detecting the reference position; a relative position detection means for detecting the relative positional relationship between the reference position and the light irradiation body; and controlling the movable mechanism in accordance with the relative position and the exposure range. and a light amount control means that controls the amount of light irradiated from the light irradiator to the plate to be processed in accordance with the relative position and the exposure range. Exposure equipment. (2) The exposure apparatus according to claim 1, wherein the exposure range input means has a surface sensor. (3) The exposure apparatus according to claim 1, wherein the light amount control means selectively exposes the exposure range.