JPH05217843A - Stepper - Google Patents

Abstract

PURPOSE:To make it possible to change the exposure conditions for each discrimination mark of each wafer at the time of exposure by providing the device with the function to read wafer discrimination marks. CONSTITUTION:A wafer discrimination mark on a wafer 9 is taken as an image into an alignment optical system 11 and then the discrimination mark can be recognized by an image processing section 12 and the discrimination mark processing section 14. Therefore, (1) job errors due to the verification of wafer marks can be reduced, (2) an experiment of classifying wafers can be done, (3) exposure can be done with an exposure area of only a part of the wafers expanded, and (4) the plural kinds of wafers is treated as the same lot and can be processed in a batch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduction projection exposure apparatus (hereinafter referred to as a stepper) which performs exposure by aligning a semiconductor substrate (hereinafter referred to as a wafer) coated with a photoresist and an exposure mask (hereinafter referred to as a reticle). Regarding).

[0002]

2. Description of the Related Art A conventional stepper has an alignment mechanism for aligning a wafer and a reticle, but does not have a mechanism for reading a wafer identification mark.

[0003]

The conventional stepper does not have a function of reading the wafer identification mark and cannot identify the wafer at the time of exposing the wafer. Therefore, the exposure condition is different for each identification mark of each wafer. It was impossible to change.

[0004]

The step bar of the present invention comprises:
An image capturing camera for reading the wafer identification mark on the wafer by using a part of the alignment mechanism, an image processing unit, and an identification mark processing unit are provided.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing an embodiment of the present invention,
2A shows a normal exposure state, and FIG. 2A is a view showing the arrangement of the shots 16 on the wafer 9 and the arrangement of the alignment marks 15 and the wafer identification marks 17, FIG.
(B) is an enlarged view of the wafer identification mark 17.

As shown in FIG. 1, during exposure, the light from the exposure light source 1 is reflected by the elliptical mirror 2 and the mirror 3, passes through the illumination optical system 4 and is reflected by the mirror 5, and the condenser lens 6 is used.
And the image of the reticle 7 is transferred to the wafer 9 on the wafer stage 10 by the reduction projection lens 8. The alignment optical system 11 is composed of a light source for illumination and a camera for converting an image into an electric signal. The image of the alignment mark 15 is captured by the image processing unit 12, the image processing unit 12 performs the image processing, the alignment processing unit 13 reads the position coordinates, and the stage 10 is driven based on this information to perform positioning, and then exposure is performed. Be seen. In the present invention, the image of the wafer identification mark 17 shown in FIG. 2 is taken in by the alignment optical system 11 before the alignment is performed, the image processing unit 12 performs the image processing, and the identification mark processing unit performs the identification. The wafer can be identified before the exposure.

Although a bar code is used for the wafer identification mark 17 in the embodiment, it is also possible to use a numeral or an alphabet.

[0008]

As described above, the present invention has a function of reading the wafer identification mark on the wafer by utilizing a part of the alignment mechanism, and therefore has the following effects.

First, since the wafer can be identified before the exposure, it is possible to check the type of wafer, the process, and the exposure condition. By registering the wafer identification mark and the exposure condition in advance, it is possible to eliminate a work error. Becomes

Secondly, when performing experiments by dividing the exposure condition level, it is possible to continuously and automatically process a plurality of wafers by setting the wafer identification mark and the condition in advance. Since it is not necessary to manually identify the wafer and set the conditions, the number of steps can be reduced.

Thirdly, the wafers in the same lot (usually 2 wafers)
It is possible to perform exposure by expanding the exposure area in order to insert the TEG shots only in a part of the wafers (5 or 50). For example, in a wafer lot consisting of 50 wafers, it is possible to preliminarily provide identification marks 1 to 50 on each wafer and to perform exposure by expanding the exposure area only for the wafer whose last digit is 0.

Fourth, it is possible to process a plurality of types of wafers in the same wafer lot. In the semiconductor manufacturing process, different products can be obtained by changing the reticle used for exposure even if the process standard is the same. Further, in the steps other than the exposure, those having the same process standard can be processed under the same conditions. For this reason, conventionally, even if the wafers of a plurality of types are processed as the same lot, the wafers are separated into a plurality of small lots before the exposure and the exposure is performed. The present invention makes it possible to automatically select and replace a reticle that matches each wafer according to pre-registered conditions by reading the wafer identification mark in the stepper. It is possible to process all at once.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a shot arrangement on a wafer and an arrangement of alignment marks and wafer identification marks.

[Explanation of symbols]

 1 Light Source for Exposure 2 Elliptical Mirror 3 Mirror 4 Illumination Optical System 5 Mirror 6 Condenser Lens 7 Reticle 8 Reduction Projection Lens 9 Wafer 10 Stage 11 Alignment Optical System 12 Image Processing Section 13 Alignment Processing Section 14 Identification Mark Processing Section 15 Alignment Mark 16 Shots 17 Wafer identification mark

Claims (1)

[Claims] 1. A reduction projection exposure apparatus for aligning an exposure mask and a semiconductor substrate to perform exposure, having a function of reading a wafer identification mark on the semiconductor substrate by utilizing a part of an alignment mechanism. Reduction projection exposure apparatus.