JPH06177005A - Aligner - Google Patents

Abstract

PURPOSE:To provide an aligner in which the works, that have not been applied with exposure, processing normally, can be discharged in a manner that they are easily detected in a post-processing step and whose occupying area is not increased. CONSTITUTION:A control circuit 10 judges, based on the information from a sensor 7 for detecting the suction status of a work P and an alignment microscope 8 for detecting the alignment mark of the work P, whether or not the work P carried in on an X-Y stage 3 is ready to be applied with exposure processing normally. When the circuit 10 judges that the work P is in such a status, the work P is applied with normal exposure processing. On the contrary, when the circuit 10 judges that the work P is not so, an exposing pattern different from that during normal exposing processing is exposed against the work P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for exposing a desired pattern on a reticle or mask plate used in a semiconductor manufacturing process or a resist on a semiconductor wafer.

[0002]

2. Description of the Related Art In this type of apparatus, when a work such as a plate or a wafer to be exposed is carried onto an XY stage, the work is vacuum-sucked by a holder on the stage and the exposure position is adjusted. To adjust the alignment. If the workpiece cannot be attracted or aligned due to warpage or loss, the workpiece is unloaded as a reject process from the stage without exposure processing. The rejected work is sent to the developing machine side as it is, or is mixedly mounted on a carrier that stores the normally exposed work. If a carrier dedicated to rejected work is prepared, store it there.

[0003]

In general, it is not possible to determine whether or not the resist on the work is exposed in the stage before the development, and therefore, when the rejected work is sent to the developing machine or when the work is exposed. In the case of being mixedly mounted on the carrier, the rejected unexposed work as well as the normally exposed work have to be developed. However, even after development, it is often difficult to determine visually whether or not exposure processing has been performed, and eventually rejected workpieces cannot be selected until some inspection process has passed, and wasteful processing is performed during this period. It takes time and money. In particular, in the case of a wafer in which pattern formation is repeated over many layers, even if it is an unexposed wafer, the pattern formed by the previous processing remains on the surface, so it is distinguished from the wafer that has been normally exposed. Is extremely difficult to do. On the other hand, when the carrier dedicated to the rejected work is provided, the above-mentioned problem does not occur, but it is necessary to newly secure a space for installing the dedicated carrier, and the area occupied by the exposure apparatus increases. There are many problems especially when a plate having a large area is targeted.

An object of the present invention is to provide an exposure apparatus which can carry out a work which has not been normally exposed to light in a state where it can be easily found in a post process and which does not increase the area occupied by the apparatus.

[0005]

1 and 3 showing an embodiment, the present invention will be described with reference to FIG.
Work state discrimination means 7, 8, 10 for discriminating whether or not the work P carried on is in a state where the exposure process can be performed normally.
It is applied to an exposure apparatus equipped with. The above-described object is to provide the reject exposure unit 10 that exposes the pattern Er1 different from the exposure pattern during the normal exposure process on the work P when it is determined that the work P cannot be normally exposed. It is achieved by providing. The exposure optical system for exposing different patterns may be provided separately from the exposure optical system for performing normal exposure processing, and different patterns are exposed using the exposure optical system for performing normal exposure processing as in the apparatus of claim 2. You may. In the device of claim 3,
The reject exposure unit 10 performs exposure outside the exposure range during normal exposure processing. In the apparatus according to the fourth aspect, the reject exposure unit 10 moves the stage 3 to expose a different pattern while exposing the exposure pattern in the normal exposure process.

[0006]

When the work state determining means 7, 8 and 10 determine that the work P is in a state where the normal exposure processing cannot be performed, the reject exposure means 10 makes an exposure pattern different from the normal exposure pattern on the work P. The pattern Er1 is exposed. If the difference between the exposure pattern Er1 by the reject exposure unit 10 and the exposure pattern in the normal exposure process is increased, it is possible to determine whether or not the normal exposure process is performed just by looking at the work P after the development process. In the apparatus according to the third aspect, the exposure pattern Er1 is formed by the reject exposure means at a position where there is usually no exposure pattern. In the apparatus according to claim 4, the exposure pattern E having a size which cannot be obtained by the normal exposure process due to the movement of the stage 3.
r1 is obtained.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the exposure apparatus of the present embodiment uses a light from a light source 1 such as a mercury lamp to reticle R.
And irradiate the pattern image with the projection lens 2 for XY
The image is reduced and projected onto the plate P placed on the stage 3, and a shutter 4 for adjusting the exposure time and a blind 5 for adjusting the irradiation range of the reticle R are provided on the optical path from the light source 1 to the plate P. ing. XY stage 3
Is a combination of two stages movable in directions orthogonal to each other to move the plate P to an arbitrary position in the horizontal plane, and a holder (not shown) for vacuum-sucking the plate P is mounted on the upper surface thereof. A loader 6 that carries the plate P into and out of the holder by gripping the plate P with a pair of arms 6a (only one of which is shown in the figure) is arranged on the side of the XY stage 3.

A control circuit 10 controls each part of the exposure apparatus. The control circuit 10 includes a shutter drive circuit 1
1, blind drive circuit 12, stage drive circuit 13,
The loader drive circuit 14 is connected. Shutter drive circuit 1
1 drives the shutter 4 at the timing commanded by the control circuit 10, the blind drive circuit 12 adjusts the opening amount of the blind 5 according to the irradiation range commanded by the control circuit 10, and the loader drive circuit 14 controls the control circuit. In response to a command from 10, the actuator (not shown) of the loader 6 is driven. The stage drive circuit 13 drives an actuator (not shown) of the XY stage 3 according to a stage drive command from the control circuit 10, and at the same time, the control circuit 10
The holder is driven in response to the plate attachment / detachment command from.
The suction operation of the plate P by the holder is monitored by the sensor 7. The sensor 7 outputs a predetermined suction completion signal to the control circuit 10 when the plate P is normally sucked.

An alignment microscope 8 is provided on the side of the projection lens 2. This alignment microscope 8 has an X-
The position of the alignment mark provided on the plate P on the Y stage 3 is detected, and the coordinate value is sent to the control circuit 10. The control circuit 10 calculates the amount of deviation between the detected alignment mark position and the regular alignment mark position, and sends a stage drive signal to the stage drive circuit 13 to drive the XY stage 3 by an amount according to the result. Output. As a result, the alignment of the plate P is adjusted.

FIG. 2 is a flow chart showing an exposure processing procedure by the control circuit 10. The reticle R corresponding to the pattern to be exposed is interposed between the blind 5 and the projection lens 2, and when the exposure process is instructed from the operation panel (not shown) of the exposure apparatus, the process by the program of FIG. 2 is started. It In step S1, a plate loading command is output to the loader driving circuit 14 to load the plate P onto the XY stage 3. In the next step S2, a timer for measuring the elapsed time of the suction operation is started, and in step S3, the holder on the XY stage 3 is driven to suck the plate P. In step S4, it is determined whether the sensor 7 has output a suction completion signal for the plate P. When it is determined that the adsorption is not completed, the process proceeds to step S5, and it is determined whether the time measured by the timer started in step S2 has reached a predetermined time. When it is determined that the predetermined time has not been reached, the process returns to step S3 and the suction operation of the plate P is continued.

When it is determined in step S4 that the suction is completed, the process proceeds to step S6, a timer for counting the elapsed time of alignment adjustment is started, and alignment adjustment is started in next step S7. In step S8, the position of the alignment mark detected by the alignment microscope 8 is compared with the regular alignment position to determine whether or not the alignment adjustment is completed. When it is determined that the alignment has not been completed, the process proceeds to step S9, and it is determined whether the time measured by the timer started in step S6 has reached a predetermined time. When it is determined that the predetermined time count has not been reached, the process returns to step S7 and the alignment adjustment is continued.

When it is determined in step S8 that the alignment is completed, the process proceeds to step S10, in which the XY stage 3, the shutter 4 and the blind 5 are controlled according to the exposure information previously input to the control circuit 10 to control the predetermined position on the plate P. An exposure pattern corresponding to the pattern image of the reticle R is exposed at the position. On the other hand, when it is determined in step S5 or step S9 that the time is up, the process proceeds to step S11, and a reject exposure process different from the exposure process in step S10 is performed. In this reject exposure process, the XY stage 3 is moved so that the “X” -shaped exposure pattern Er1 is formed on the plate P as shown in FIG. To drive. The range Zs shown by the dotted line in FIG. 3 is the exposure range when the blind 5 is fully opened while the XY stage 3 is stopped, and in the normal exposure process of step S10,
A large number of pattern images of the reticle R are formed by alternately repeating the exposure within the range Zs and the movement of the XY stage 3.

After the exposure process in step S10 or step S11 is completed, the process proceeds to step S12, the plate is released from the holder, and the plate P is unloaded from the XY stage 3 by the loader 6. The carried-out plate P is sent to the development processing step.

In the above processing procedure, if the plate P cannot be attracted to the holder due to deformation such as warpage, step S
4 continues to be denied, step S5 is affirmed due to time-up, the reject exposure process is performed in step S11, and the plate P is unloaded in step S12. Further, when the alignment microscope 8 cannot detect the alignment mark due to the loss of the alignment mark or the contamination of the plate P, and when the amount of alignment deviation exceeds the adjustable range, step S8 continues to be denied, and step S8 is performed due to time-up. If S9 is positive, step S
Rejection exposure processing is performed in step 11, and step S12
The plate P is unloaded. As is clear from FIG.
Since the exposure pattern Er1 by the reject exposure process is completely different from the exposure pattern by the normal exposure process, it is possible to determine that the normal exposure process has not been performed at a glance after the development process. In this embodiment, since the plate P subjected to the reject exposure process and the plate subjected to the normal exposure process are sent to the developing process without being distinguished from each other, it is not necessary to prepare a carrier for exclusive use of the plate which cannot be normally subjected to the exposure process.
The area occupied by the equipment does not increase at all.

In this embodiment, since the reject exposure process is performed while moving the XY stage 3, the exposure pattern E having a size that cannot be obtained by one normal exposure process.
r1 can be exposed and the plate can be more easily identified. However, the present invention is not limited to such an aspect, and various changes can be made as long as the pattern can be visually recognized after development, which is different from the exposure pattern during normal exposure processing. Assuming that the exposure range by the normal exposure process is within the range Za surrounded by the chain double-dashed line in FIG.
If the exposure pattern of the reject exposure process is formed outside the area, the exposure pattern exists at a position where the exposure pattern cannot normally exist, so that the plate P subjected to the reject exposure process can be more easily discriminated. Become. In this respect, the exposure range Z of a normal exposure pattern as shown in FIG.
The exposure pattern Er2 is not limited to the example in which the reject exposure process is performed inside and outside a, but the exposure pattern Er2 may be formed by the reject exposure process only outside the range Za as shown in FIG. The exposure optical system used for the reject exposure processing may be provided separately from the exposure optical system that performs normal exposure processing.

The exposure time of the reject exposure process may be set longer than the exposure time of the normal exposure process. As the exposure time becomes longer, the exposure pattern formed on the plate P expands accordingly, so that the difference between the exposure pattern by the normal exposure process and the exposure pattern by the reject exposure process becomes more distinct.

In the embodiment, the exposure apparatus using the plate P as a work is taken as an example, but the present invention is not limited to this, and any exposure that optically forms a pattern on a resist on a wafer or other various works. Applies to equipment.

In the above embodiment, the sensor 7, the alignment microscope 8 and the control circuit 10 constitute the work state determining means, and the control circuit 10 constitutes the reject exposure processing means.

[0020]

As described above, according to the present invention, by setting a large difference between the exposure pattern by the reject exposure means and the exposure pattern at the time of normal exposure processing, it is possible to normalize the work only at a glance after the development processing. Since it is possible to determine whether or not various exposure processes have been performed, it is possible to remove the work that could not be normally exposed at the stage immediately after development to minimize the generation of dead time and cost. Since it is not necessary to add a carrier dedicated to the plate that could not be normally exposed, the area occupied by the apparatus does not increase. In this respect, if the exposure optical system is common as in the apparatus of claim 2, the increase of the area occupied by the apparatus can be prevented more reliably. In the apparatus according to the third aspect, since the exposure pattern is formed by the reject exposure means at a position where there is usually no exposure pattern, it is easier to discriminate the plate that could not be normally exposed. In the apparatus according to the fourth aspect, it is possible to expose an exposure pattern having a size that cannot be obtained by one normal exposure process by moving the stage, and it becomes easier to discriminate a plate that has not been normally exposed.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of exposure processing by the control circuit of FIG.

3 is a plan view of a plate that has been subjected to reject exposure processing by the apparatus of FIG.

FIG. 4 is a diagram showing a modification of FIG.

[Explanation of symbols]

 3 XY stage 7 sensor 8 alignment microscope 10 control circuit P plate R reticle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G06F 15/46 7218-5L H01L 21/66 J 7377-4M

Claims (4)

[Claims] 1. An exposure apparatus having a work state determination means for determining whether or not a work carried in on a stage is in a state in which normal exposure processing can be performed, and when the work is in a state in which normal exposure processing cannot be performed. An exposure apparatus comprising: a reject exposure unit that exposes a pattern different from an exposure pattern at the time of a normal exposure process on the work when determined. 2. The exposure apparatus according to claim 1, wherein the reject exposure unit exposes the different pattern by using an exposure optical system that performs the normal exposure process. 3. The exposure apparatus according to claim 1, wherein the reject exposure means performs exposure outside the exposure range during normal exposure processing. 4. The reject exposure means exposes the different pattern by moving the stage while exposing the exposure pattern at the time of normal exposure processing. Exposure equipment.