JPH02192112A - Aligner - Google Patents

Abstract

PURPOSE:To make it possible to prevent the collision generating by the movement of a plurality of pickups in an easy and effective manner by a method wherein a plurality of pickups are shifted while a safe region, in which interference is automatically prevented, is being secured. CONSTITUTION:The driving systems, in the directions vertical and parallel to the side of the exposure region 6 corresponding to pickups 1 to 4, are provided. Even when the relations between the exposure region 6, the arrangement of a position-detecting mark and the size of the pickups 1 to 4 are critical, or even when there are pickups which cannot be driven due to a mechanical or electrical failure, an action is taken to prevent the generation of a collision between the pickups. To be more precise, each pickup is driven toward the outside in vertical direction against the side of the exposure region 6 corresponding to the pickups 1 to 4 respectively. As a result, the throughput of the entire device can be improved by conducting the movement of the pickups excellently when a pickup optical system is set.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to exposure apparatuses (hereinafter referred to as "exposure apparatuses") that use light or X-rays, such as reduction projection type, mirror projection type, and proximity type. The present invention relates to an exposure apparatus in which a detection optical system for aligning a mask and a substrate to be exposed, a so-called pickup optical system, is suitably moved during setting.

(Prior Art) In recent years, as the circuit patterns of semiconductor integrated circuits have become finer, improving alignment accuracy has become an increasingly important issue. In order to solve the above-mentioned problem, a method of detecting positional information at multiple points of an exposure pattern and performing highly accurate positioning has been considered.

However, detecting the positions of multiple points while moving one pickup, for example, is not preferable in terms of accuracy, both in terms of time and stability. For this reason, it has long been desired to arrange multiple pickups so that position information can be detected at multiple points simultaneously.

(Problems to be Solved by the Invention) However, since the pickup includes a built-in optical system and electrical system necessary for position detection, a certain degree of physical size is required.

The problem with increasing the number of pickups can be said to be the conflict between the physical size and the arrangement of multiple pickups. Generally, the size of the exposure pattern changes depending on the LSI to be manufactured, and even when manufacturing one LSI, the arrangement of position detection marks is changed depending on the process. There is a problem in that the setting position of the pickup must be changed in response to changes in the arrangement of the detection marks caused by changes in the exposure angle of view and process.

Also, moving a large number of pickups creates a mechanical interference area in the movement range of the pickups,
There was a problem in that it created a risk of collision.

On the other hand, pickups are required to detect positions with high precision.

The built-in optical and electrical components are arranged and adjusted extremely precisely for this reason, and it is obvious that external disturbances such as collisions will have an adverse effect.

As mentioned above, changing the setting positions of multiple pickups is extremely dangerous, and for this reason, there is a clear possibility of collision in exposure and writing equipment used in mass-production semiconductor manufacturing, which requires frequent changes during the semiconductor manufacturing process. It was only adopted under the condition that there was no.

(Means for Solving the Problems) In order to provide an exposure apparatus in which a method for moving a large number of pickups is properly carried out, the pickups automatically secure a safe area in which mutual interference does not occur. This avoids the risk of collision. As a result, even when the relationship between the exposure area, position detection mark placement, and pickup size is critical, it is possible to detect multiple points, and high-precision alignment is achieved in semiconductor manufacturing exposure and writing equipment for mass production. . For this reason, the present invention is characterized in that each pickup has independent drive systems in directions perpendicular and parallel to the sides of the corresponding exposure area. By appropriately controlling the drive system as described below, collisions between the pickups can be avoided.

(Embodiment) FIG. 1 is a schematic view of the main parts of the configuration of an exposure apparatus to which the present invention is applied, showing it from the exposure axis side and from the side. The upper side is the exposure axis side, and the lower side is the side view. An exposure pattern 6 illuminated by a light source (not shown) is formed on the mask 7, and this pattern is transferred onto an exposed substrate 8 placed close to the mask 7.

1.2 and 3.4 are pickups for position detection corresponding to the four sides constituting the exposure area 6, which detect position detection marks pre-engraved on the exposure pattern 6 and the substrate B to be exposed, and detect both sides. Measure the amount of positional deviation. The amount of positional deviation is fed back to the stage 9, and the relative position between the mask 7 and the substrate 8 to be exposed is adjusted. Exposure is performed when the amount of positional shift becomes smaller than a predetermined value, and the exposure pattern 6 on the mask 7 is printed onto the substrate 8 to be exposed.

The pickups 1, 2, 3.4 are arranged on the same base substrate 5. Each pickup has two independent drive systems, namely motors 11.21 and 31.41 that drive in a direction perpendicular to the side of the exposure pattern 6 in the plane of this figure, and motors 11.21 and 31.41 that drive in a direction parallel to the side of the exposure pattern 6. motor 12,
The characteristic of this embodiment is that it has an angle of 22°32.42.

FIG. 2 shows a block diagram of an embodiment of a control system for moving the pickups 1, 2, 3.4. 4
The movement of the two pickups is done by the parallel IF unit 205.
It is executed in response to a target position movement instruction from the host controller unit via the parallel l
Reported to the host controller unit via F2O3.

The direction drive is controlled by a microprocessor 201 and a ROM 203 that are independent of the host controller unit of the exposure apparatus.
．． This is done by RAM 204. The microprocessor 201 serves to independently drive each axis by giving drive commands to controllers 211 to 218 of servo motors that drive each of the pickups 1, 2, 3.4 in the vertical and parallel directions. As a result, each pickup can be moved to any position relative to each drive shaft.

When the servo motor controllers 211-218 receive a drive command from the microprocessor 201, they determine acceleration/deceleration values according to the difference between the current position and the target position, and provide corresponding speed commands to the servo motor drivers 221-228. As a result, motors 11 to 41 and 12 to 42 are driven, and the amount of drive of these motors is determined by encoders 241 to 42.
248. The pulse output from the encoder is counted and servo control is performed, and when movement to the target position is completed, the microprocessor 201 is notified of the end of driving.

Further, 202 is a timer unit in which a certain timer value is set in advance. This unit serves to provide a designated time elapsed signal to the microprocessor 201 when a set time has elapsed after starting time counting.

FIG. 3 shows the procedure for moving the pickup. The pickup movement control system starts this procedure in response to a movement instruction from the host controller unit. After receiving the movement target position for each pickup from the host controller unit in step 301, step 3
In step 02, when the pickups are finally moved to the designated target positions, it is checked that the positions of the pickups do not interfere with each other. If it is determined at this point that interference between the pickups will occur at the target position, the process proceeds to step 310 without driving the pickups, and an abnormal termination due to unsuitability of the target position is reported to the host controller unit.

If the suitability of the target position is confirmed, the process advances to the next pickup drive procedure 303. In step 303, when the four pickups are subsequently driven simultaneously, an operation is performed so that a collision will not occur between the pickups even if there is a pickup that cannot be driven due to mechanical or electrical failure. That is, each pickup is driven outward in a direction perpendicular to the side of the exposure area corresponding to each pickup to ensure a safe area for subsequent driving.

The pickup is moved by the servo motor controller 2.
This is done by giving drive commands to the servo motor drivers 221 to 228 corresponding to the axes to be driven. Meanwhile, at the same time, the timer unit 20
In step 2, the timer value is set to the time +α required to complete driving in normal operation, and then a time count is started. If there is a pickup that continues to be driven even after the set time has elapsed, it is assumed that some abnormality has occurred, and a drive stop command is given to the corresponding servo motor controller 211 to 218 to end the drive. . The drive shaft that continues to be driven is processed as if it has ended abnormally.

The following step 304 is a routine for determining whether all pickups have been completed normally. If there is one that has ended abnormally, the process proceeds to step 310, where the host controller unit is informed that the drive has ended abnormally, the drive shaft that caused the abnormality, the details of the abnormality, etc., and the process ends. If all pickups are successfully driven, proceed to step 305.
Then, an operation is performed to move each pickup to a target position in a direction parallel to the corresponding side of the exposure area. In this procedure, the final movement target position in the parallel direction is set as a drive command position for the servo controller of the parallel direction axes of each pickup, and the pickups are driven in the same manner as in step 303. The following step 306 is step 304
This is a routine for determining normal completion of driving similar to . When the driving in the parallel direction is successfully completed, the process proceeds to step 307. In step 307, the movement of each pickup to the final destination position in the vertical direction is executed in the same manner as in step 305, and step 30
8 to confirm that the drive of each pickup is completed normally. When the driving of all the pickups is completed normally in step 308, the host controller unit reports to the host controller unit in step 309 that the movement of each pickup to the movement target position has been completed normally, and the process is completed. finish.

FIG. 4 is a schematic diagram showing how each pickup is moved based on the moving method of the present invention. 1゜2.3.4 indicated by a solid line in Fig. 4(A) indicates the current pickup position, and la, 2a, indicated by a broken line,
3a and 4a indicate the final destination position of each pickup instructed by the host controller unit.

In the subsequent figures as well, the broken lines indicate the final destination position of each pickup.

Now, in this example, since no interference occurs between the pickups even after moving to the final destination position, step 302 in FIG. 3, ie, the determination of the suitability of the destination position, has been passed. Therefore, as shown by the arrow in Figure 4 (A), when moving each pickup to its target position, move each pickup to the corresponding exposure area until it reaches an area where mutual interference will not occur even if there is a poorly driven pickup. Drive outward perpendicularly to the edge. lb, 2b, 3b, and 4b in FIG. 4(B) indicate the positions of the respective pickups when the above driving is normally completed. Next, each pickup is moved in the direction indicated by the arrow in the figure, which is parallel to the side of the corresponding exposure area. Each pickup is driven to a target position in the parallel direction. Fig. 4(C) shows the pickup position lc, 2 when the parallel direction movement is successfully completed.
c, 3c, and 4c are shown. Then, as shown by the arrow in Figure 4(C), if the drive is completed normally to the target position in the direction perpendicular to the side of the corresponding exposure area, the dashed line and solid line will appear as shown in Figure 4(D). Overlapping, final pickup position 1d.

2d, 3d, and 4d match the target positions 1a, 2a, 3a, and 4a instructed by the host controller unit, and the movement is completed. In this way, in this embodiment, the distance between each pickup is first widened, and then movement is performed while checking the mutual distance. Therefore, when one of the pickups is driven, a failure in the mechanical system or the electrical system may cause the pickup to be unable to be driven. However, no interference occurs between the pickups.

FIG. 5 is a diagram showing the movement procedure of the pickup according to the second embodiment. In addition to the movement method shown in the first embodiment, the movement target position instructed by the host controller unit is perpendicular to the current position. This takes into consideration the case where it is outside. The movement outward in the vertical direction has the special feature that there is absolutely no interference between the pickups.
Taking advantage of this special feature, it is possible to shorten the time required for movement. When moving outward in the vertical direction, the interference area between the pickups is reduced even when moving in the parallel direction later, and it is possible to take advantage of this advantage.

Steps 301 to 310 indicated by the numbers in FIG. 5 are the same processes as in the embodiment shown in FIG. 3, so their explanation will be omitted here. The addition in the example of FIG. 5 is a consideration for the special case described above, and this addition procedure allows the most time-consuming operation of driving the motor to be bypassed. The indicator for this is a flag indicating vertical outward movement, and steps 501 and 505°5
This is a series of processing for the flag inserted as 08.

In FIG. 5, before driving the pickup to the safe area in step 303, there are determination steps 502 to 504 for selecting pickups that are located at the target position or vertically outside the current position, and determination steps 502 to 504 that select the pickup that is located at the target position or vertically outside the current position. Driving procedures 506 and 507 for driving the pickup are added. Since the pickup driven at 506° and 507 is quickly driven to the target position in the vertical direction, it is possible to eliminate unnecessary evacuation operations and to move while ensuring a safe area. Also, steps 509 and 510 are steps 506 and 5
This is a movement procedure for the remaining pickups of the pickups that have been moved to the vertically outer target position by step 07, that is, the pickups whose target positions are vertically inner than the current position.

The flow in FIG. 5 is seemingly more complicated than the flow in FIG.

However, since the inserted judgment procedure is carried out electrically, it only takes a short time, whereas the reduction in unnecessary retracting operations resulting from this judgment actually leads to a reduction in the number of times the motor is driven and the driving distance, which takes the most time. Therefore, the effect is enormous. The effect is that the throughput of the entire fruiting apparatus is improved.

(Effects of the Invention) As explained above, the present invention makes it possible to easily and efficiently prevent collisions due to the movement of a large number of pickups by devising a driving method.

Normally, trying to realize this kind of thing requires complicated synchronized driving of multiple pickups and collision prevention sensors such as photo sensors and microswitches, which not only complicates the system configuration but also costs a lot. It's a bigger burden than the invention.

This makes it possible to perform safe and efficient multi-point position detection even in mass-production semiconductor manufacturing exposure and lithography equipment, resulting in improved alignment accuracy and higher precision in semiconductor integrated circuits. This contributes to

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an exposure apparatus embodying the present invention;
3 is a block diagram of the pickup drive control unit, FIG. 3 is a pickup movement processing procedure in the first embodiment, FIG. 4 is an example of pickup movement in the first embodiment, and FIG. 5 is a pickup movement process in the second embodiment. procedure. In the figure, 1, 2, 3.4 are pickup optical systems for positioning, 6 is an exposure pattern on a mask, 7 is a mask, 8 is a substrate to be exposed, 11, 21, 31.41 are pickups 1, 2, Drive system for moving 3.4 in the direction perpendicular to the side of the corresponding exposure angle of view, 12, 22, 32.4
Reference numeral 2 denotes a drive system for moving the pickups 1, 2, 3.4 in a direction parallel to the side of the corresponding exposure angle of view. Patent applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) When having a plurality of position detection optical systems disposed corresponding to a plurality of predetermined positions near the exposure area, and moving the optical systems simultaneously to align the respective predetermined positions, An exposure apparatus characterized by determining whether optical systems do not interfere with each other even if at least one optical system does not move. (2) having a plurality of position detection optical systems disposed corresponding to a plurality of predetermined positions near the exposure area, and when simultaneously moving the optical systems to align the respective predetermined positions, An exposure apparatus characterized in that the optical systems are first arranged in such a state that the optical systems do not interfere with each other even if at least one optical system does not move.