JPH07201715A - Pattern aligning method - Google Patents

Abstract

PURPOSE:To provide a pattern aligning method cutting down the required time for changing operation of pattern images in the pattern aligning of a plurality of wafers for improving the productivity of semiconductor device. CONSTITUTION:Within the pattern aligning method, the first and second pattern images are formed on one wafer by pattern aligning using a stepper and then the pattern images are likewise formed on a plurality of wafers. Furthermore, after arranging wafers on the stepper, S102, S109 are performed; after shifting a flare panel of the stepper, S105, S111 are performed; after arranging the second (the first) pattern images, S106, S112 are performed; after arranging next wafers on the stepper, S109. S102 are performed. Next, without shifting the flare panel, the second (the first) pattern images are formed in S110, S104. Through these procedures, the frequency of the flare panel operations resultant from the change of pattern images are to be per lot ((kinds of pattern images)-1) X (number of wafers) + 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern exposure method, and more particularly to a pattern exposure method for forming a pattern image on a wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, a step-type reduction projection exposure apparatus, a so-called stepper, is used when forming a pattern image on a wafer by pattern exposure. As shown in FIG. 5, in pattern exposure using a stepper, by repeating the movement of the wafer and the exposure,
Similar pattern images are repeatedly formed on one wafer 5. Then, the first pattern image 5 such as A is formed on the wafer 5 by repeated exposure using a stepper.
When a second pattern image 503 of 01 and B is formed and the first and second pattern images 501 and 502 are similarly arranged on a plurality of wafers, pattern exposure is performed as follows. .

First, a photomask used for pattern exposure is prepared. This photomask is formed by dividing the exposure range of the photomask into first and second exposure ranges. Then, the mask pattern of the first pattern image 501 is formed in the first exposure range, and the mask pattern of the second pattern image 502 is formed in the second exposure range. Using this photomask, pattern exposure is performed according to the flowchart shown in FIG.

As shown in the figure, in the first step S61,
As the wafer load, the first wafer is placed on the stepper on which the above photomask is installed. Then, the wafer is aligned. In the second step S62, the shading plate installed on the stepper is moved to cover the portion of the photomask other than the first exposure range with the shading plate.
Next, in a third step S63, the repeated exposure operation by the stepper is performed to arrange the first pattern image on the wafer. After that, in the fourth step S64, the light shielding plate is moved so as to cover the portion other than the second exposure range in the photomask. Then, in a fifth step S65, the stepper performs the repeated exposure operation to arrange the second pattern image on the wafer. As above
After arranging the first and second pattern images on one wafer, the first wafer is removed from the stepper as wafer unloading in the sixth step S66. Then, in a seventh step S67, it is determined whether or not the pattern exposure is continued for the next wafer. When the pattern exposure is continued, the process returns to the first step S61, and then the seventh step S6.
Repeat up to 7.

Further, as another example of performing the same pattern exposure as described above, there is a method using a plurality of photomasks. In this method, a photomask for forming a first pattern image and a photomask for forming a second pattern image are prepared. Then, in the step before the step of moving the light shielding plate shown by in the flowchart of FIG.
Perform the step of replacing the photomask installed on the stepper.

[0006]

However, the above pattern exposure method has the following problems. That is, in the above pattern exposure method, the order of forming patterns is similarly determined for each wafer. Therefore,
The method of performing exposure with one photomask requires a step of moving the light shielding plate before performing the exposure operation for forming each pattern image. Therefore, for each pattern exposure of one wafer, a time obtained by multiplying the number of types of patterns by the movement of the light shielding plate and the operation time associated therewith is added to the processing time. For example, if the time required for each movement of the light-shielding plate and the associated movement is 20 seconds, in order to process 50 wafers in one lot, 20 seconds × 2 in addition to the actual exposure operation.
Pattern x 50 sheets = 2000 seconds is required. This causes a decrease in work efficiency.

In the pattern exposure method using a plurality of photomasks, it takes about 120 seconds for each replacement of the photomasks and various operations associated therewith. For example, in order to process 50 wafers in the same manner as described above, it takes 12000 seconds to replace the photomask and perform various operations. This is not a practical method because it significantly lowers the work efficiency in comparison with the above method.

Therefore, the present invention provides a pattern exposure method that solves the above problems, and an object thereof is to improve the productivity in the manufacturing process of semiconductor devices.

[0009]

According to the present invention, which has achieved the above-mentioned object, a plurality of different pattern images are formed on one wafer by pattern exposure using a stepper, and the plurality of wafers are similarly formed. It is a pattern exposure method for forming a pattern image. In this pattern exposure method, the wafer is placed on the stepper to form the last pattern image on the wafer, and then the next wafer is placed on the stepper, and the last pattern image is used as the first pattern image on the next wafer. Form.

In the present invention, the light exposure plate of the stepper is moved to change the exposure range of the photomask provided in the stepper, thereby performing pattern exposure.
Thus, in the pattern exposure method of arranging a plurality of different pattern images on one wafer, in the pattern exposure of one wafer, after moving the light shielding plate of the stepper and arranging the last pattern image on the wafer, The pattern exposure of the next wafer is performed with the light shielding plate kept at the same position to form the first pattern image on the wafer.

Further, in the present invention, in the pattern exposure method of arranging a plurality of different pattern images on one wafer by exchanging the photomasks provided on the stepper and performing pattern exposure, one wafer is used. In the pattern exposure, after the photomask is exchanged and the last pattern image on the wafer is arranged, the pattern exposure on the next wafer is performed by the photomask to form the first pattern image on the wafer.

[0012]

In the above pattern exposure method, since the same pattern image is formed in the last pattern exposure of one wafer and the first pattern exposure of the next wafer, the number of operations required for changing the pattern image is reduced. For each lot, {(type of pattern image) −1} × (number of wafers) +1. Therefore, compared with the pattern exposure method in which the order of forming pattern images is fixed, the number of operations is (number of wafers)-
It is reduced once, and the processing time of the entire lot is shortened.

By changing the pattern image by moving the shading plate in the above method, in the same comparison as above, the number of operations associated with the movement of the shading plate is reduced in the same manner as described above, and the entire lot is reduced. Processing time is shortened.

Further, by changing the pattern image by exchanging the photomask in the above method, in the same comparison as the above, the number of operations associated with exchanging the photomask is reduced as in the above, and the whole lot is reduced. Processing time is shortened.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the flowchart of FIG. In the pattern exposure explained in the first embodiment, as shown in FIG. 2, for example, a first pattern image 201 of A and a second pattern image 202 of B are formed on one wafer 2 by using a stepper. To form. First, as shown in FIG. 3, one photomask 3
To prepare. This photomask 3 divides the exposure range of the photomask into two exposure ranges 301 and 302,
The mask pattern of the first pattern image is formed in the first exposure area 301, and the mask pattern of the second pattern image is formed in the second exposure area 302. When arranging the first pattern image on the wafer using this photomask 3, the first pattern images are formed by the light shielding films 31 to 34.
Exposure is performed in a state in which the area other than the exposure area 301 is covered. Then, when forming the second pattern image, the light-shielding films 31 to 34 are moved so as to cover the area other than the second exposure area 302 and exposure is performed. The light shielding films 31 to 34 are arranged on the stepper on which the photomask 3 is installed.

The procedure of pattern exposure by the stepper will be described below. First, as shown in FIG. 1, a first step S1
At 01, the above photomask is installed on the stepper. Then, in the second step S102, as the wafer loading, the first wafer is placed on the stepper, and the wafer alignment is performed.

Next, in the third step S103, it is determined whether or not the wafer placed on the stepper is the first wafer to be processed. When it is determined that the wafer is the first wafer, the process proceeds to the initial step S130, and the light blocking plate is moved to cover the photomask except the first exposure range with the light blocking plate. Further, since the diaphragm of the optical system of the stepper changes with the movement of the light shielding plate, the exposure dose of the exposure light is measured and corrected in this step.

Then, in the fourth step S104, the exposure operation for the first pattern image is repeated to form the first pattern image on the wafer.
Arrange the pattern images of.

After the above steps, in the fifth step S105,
The shading plate is moved to cover the area other than the second exposure area of the photomask with the shading plate. Further, since the diaphragm of the optical system of the stepper changes with the movement of the light shielding plate, the irradiation amount of the exposure light is measured and corrected.

Then, in the sixth step S106, the exposure operation of the second pattern image is repeated to form the second pattern image on the wafer.
Arrange the pattern images of.

As described above, the first wafer is placed on the first wafer.
After forming the second pattern image and the pattern image of
In step S107, the first wafer is removed from the stepper as wafer unloading. And the eighth step S10
At 8, it is determined whether or not pattern exposure is continued for the next wafer. When it is determined that the pattern exposure is not continued, the pattern exposure is ended. If it is determined to continue, the process proceeds to the ninth step S109.

In the ninth step S109, the second wafer is loaded and placed on the stepper. Then, the wafer is aligned.

Then, in the tenth step S110, the second
The pattern image exposure operation is repeated to arrange the second pattern image on the second wafer.

Next, in an eleventh step S111, the light shield plate is moved to cover the photomask except the first exposure range with the light shield plate. The exposure amount of exposure light is measured and corrected along with the movement of the light shielding plate.

Then, in the twelfth step S112, the first
The exposure operation of the pattern image 201 is repeated to form a first pattern image on the second wafer.

As described above, the first wafer is placed on the second wafer.
Forming the first pattern image and the second pattern image
In step S113 of step 3, wafer unloading is performed, and the second wafer is removed from the stepper. And the fourteenth step S
At 114, it is determined whether or not pattern exposure is to be continued for the next wafer. When it is determined that the pattern exposure is not continued, the pattern exposure is ended. When it is determined to continue, the process returns to the second step S102, and the pattern exposure for the third and subsequent wafers is continued according to the flowchart.

In the pattern exposure method of the above embodiment, the last pattern exposure of one wafer and the first pattern exposure of the next wafer are performed without moving the light shielding plate. Therefore, the number of movements of the light shielding plate per lot is {(type of pattern image) -1} × (number of wafers) +1. Therefore, compared with the method in which the order of forming the pattern images is fixed, the number of movements of the light shielding plate is reduced by (the number of wafers) −1, and the processing time of the entire lot is shortened. For example, if it takes 20 seconds to move the shading plate and measure and correct the exposure light irradiation amount, and pattern exposure is performed on 50 wafers in one lot, the total amount required to move the shading plate in the above-described embodiment. The time is {(2 pattern-1) x 50 sheets + 1} times x 20 seconds = 1020 seconds. On the other hand, in the method in which the pattern image formation order is fixed, 2 patterns × 50 sheets × 20 seconds =
2000 seconds. Therefore, the total processing time is about 1
It is shortened by 6 minutes.

Next, a second embodiment will be described based on the flowchart of FIG. In the pattern exposure described in the second embodiment, two kinds of patterns, a first pattern image 201 and a second pattern image, are formed on one wafer 2 as in the first embodiment shown in FIG. Arrange different pattern images. In this embodiment, first, a first photomask on which the mask pattern of the first pattern image 201 is formed and a second photomask on which the mask pattern of the second pattern image is formed are prepared.

The procedure of pattern exposure by the stepper will be described below. First, as shown in FIG. 4, a first step S4
At 01, the first photomask is placed on the stepper.
In this step, the light shielding plate of the stepper is moved according to the exposure range of the first photomask. Furthermore, since the diaphragm of the optical system of the stepper changes with the movement of the light shielding plate, the exposure dose of the exposure light is measured and corrected in this step.

Next, in the second step S402, as wafer loading, the first wafer is placed on the stepper, and wafer alignment is performed.

Then, in the third step S403, the exposure operation of the first pattern image is repeated to form the first pattern image on the first wafer.

After the above steps, in the fourth step S404,
The first photomask placed on the stepper is replaced with the second photomask. In this step, the light shielding plate of the stepper is moved according to the exposure range of the second photomask.
Furthermore, since the diaphragm of the optical system of the stepper changes with the movement of the light shielding plate, the exposure dose of the exposure light is measured and corrected in this step.

Then, in the fifth step S405, the exposure operation of the second pattern image is repeated to form a second pattern image on the first wafer.

As described above, the first wafer is placed on the first wafer.
After forming the second pattern image and the pattern image of
In step S406, the first wafer is removed from the stepper as wafer unloading. And the seventh step S40
At 7, it is determined whether or not pattern exposure is continued for the next wafer. When it is determined that the pattern exposure is not continued, the pattern exposure is ended. If it is determined to continue, the process proceeds to the eighth step S408.

In the eighth step S408, the second wafer is placed on the stepper as a wafer load. Then, the wafer is aligned.

Then, in the ninth step S409, the exposure operation of the second pattern image is repeated to arrange the second pattern image on the second wafer. Then, in the tenth step, the photomask exchange operation is performed in the same manner as the fourth step S404, and thereafter, pattern exposure is performed according to the flowchart from the tenth step S410 to the thirteenth step S413, and a plurality of wafers are exposed. Similarly, pattern exposure is performed.

In the pattern exposure method of the second embodiment, the last pattern exposure of one wafer and the first pattern exposure of the next wafer are performed without exchanging the photomask. Therefore, as in the first embodiment,
As compared with the method in which the order of forming pattern images is fixed, the number of times the photomask is replaced is reduced by (the number of wafers) −1, and the processing time of the entire lot is shortened. For example, when it takes 120 seconds to move the photomask and the light shielding plate associated therewith and to measure and correct the exposure light irradiation amount, and pattern exposure is performed on 50 wafers in one lot, the light shielding plate of the above embodiment is used. The total time required to move is {(2 pattern-1) x 50 sheets +
1} times × 120 seconds = 6120 seconds. On the contrary,
In the method in which the formation order of pattern images is fixed, 2 patterns x
50 sheets × 120 seconds = 12000 seconds. Therefore,
The overall processing time is reduced by about 100 minutes. Further, in this method, since different photomasks are used for the respective pattern images, the degree of freedom in designing the mask pattern formed on the photomask is improved as compared with the first embodiment.

In the above first and second embodiments, 2
The case of forming different kinds of pattern images on one wafer has been described as an example. However, the present invention is not limited to this, and can be applied to the case where three or more types of pattern images are formed. Further, the above-described embodiment can be applied even when the formation areas of the first pattern image and the second pattern image are different.

[0039]

As described above, according to the first pattern exposure method of the present invention, the pattern image lastly formed on one wafer is formed as the first pattern image on the next wafer. By reducing the number of image changing operations, the processing time required for pattern exposure of the entire lot can be shortened. Therefore, the productivity of the semiconductor device can be improved. In the second pattern exposure method of the present invention, since the pattern image is changed by moving the light shield plate in the first pattern exposure method, the time required for various operations accompanying the movement of the light shield plate is shortened, and the semiconductor device is reduced. The productivity of can be improved. Also,
In the third pattern exposure method of the present invention, since the pattern image is changed by exchanging the photomask in the first pattern exposure method, the first pattern exposure method is performed while maintaining the degree of freedom in designing the mask pattern formed on the photomask. As in the second method, the productivity of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating a first embodiment.

FIG. 2 is a diagram illustrating a first embodiment.

FIG. 3 is a diagram illustrating a first embodiment.

FIG. 4 is a flowchart illustrating a second embodiment.

FIG. 5 is a diagram illustrating a conventional example.

FIG. 6 is a flowchart illustrating a conventional example.

[Explanation of symbols]

 2 Wafer 3 Photomask 31, 32, 33, 34 Light-shielding plate 201 First pattern image 202 Second pattern image 301 First exposure range (exposure range) 302 Second exposure range (exposure range)

Claims (3)

[Claims] 1. A pattern exposure method for forming a plurality of different pattern images on one wafer by pattern exposure using a stepper, and further forming pattern images on a plurality of wafers in the same manner. A pattern characterized by forming a final pattern image on the wafer and then installing the next wafer on a stepper to form the final pattern image as a first pattern image on the next wafer. Exposure method. 2. The pattern exposure method according to claim 1, wherein the exposure area of a photomask arranged on the stepper is changed by moving the light shielding plate of the stepper to perform pattern exposure, and a single wafer is exposed. A pattern exposure method for arranging a plurality of different pattern images, wherein in the pattern exposure of one wafer, the light shield plate of the stepper is moved to arrange the last pattern image on the wafer, and then the light shield plate is placed at the same position. A pattern exposure method, characterized in that the pattern exposure of the next wafer is performed and the first pattern image on the wafer is arranged. 3. The pattern exposure method according to claim 1, wherein pattern exposure is performed by exchanging a photomask provided on the stepper, and a plurality of different pattern images are arranged on one wafer. In the pattern exposure of one wafer, after exchanging the photomask and arranging the last pattern image on the wafer, pattern exposure of the next wafer is performed by the photomask to perform the first pattern on the wafer. A pattern exposure method characterized by arranging images.