JPH04170019A - Projection exposure device - Google Patents

Abstract

PURPOSE:To enable exposure to be made automatically according to a mask corresponding to a ROM code number by encoding a ROM code number with an ultraviolet rays laser exposure device which is incorporated in a projection exposure device and then printing it. CONSTITUTION:A wafer 1a which is subjected to coating treatment of phot resist which is set to a loader cassette 2 is carried to a projection exposure chamber 7 by a transport arm 4 and is set to a wafer stage 8. Then, the wafer stage 8 travels to a part below a code-printing part 6 and then prints codes. Then, the wafer 1a returns to a normal position, performs projection exposure using a mask corresponding the ROM code, and further a wafer 1b which is subjected to exposure treatment is carried out to an unloader cassette 3 by a projection exposure chamber 7, thus achieving exposure operation automatically for a small amount of and a number of types of ROM code switched products and enabling throughput at a mass-production line to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a projection exposure apparatus used in a photolithography process for manufacturing semiconductor devices.

[Conventional technology]

Generally, in an integrated circuit device incorporating a m as k ROM circuit, a ROM code number is assigned to each circuit device. This ROM code number is engraved with alphanumeric characters on a certain area of the wafer using laser marking technology in the first step of the semiconductor wafer process, and is then engraved with alphanumeric characters on a partial area of the wafer using laser marking technology.
The code numbers were identified visually or with an expensive optical alphanumeric reader, and exposed using a mask corresponding to each ROM code number.

[Problem to be solved by the invention]

In the conventional exposure method described above that uses a mask compatible with the ROM code of an integrated circuit containing a built-in mask ROM circuit, there are hundreds of ROM code numbers that are engraved on a part of the wafer using laser marking technology. , a low-volume, high-mix production format is adopted in which the number of products required for each individual ROM code is small.

This increases the number of complex tasks required during exposure work, such as visually identifying the ROM code, searching for the mask, and checking the correspondence between the ROM code and mask number, resulting in exposure using a mask other than the specified ROM code mask. The risk was high.

In contrast to the above-described conventional method of visually identifying the number for each ROM code, the present invention encodes the ROM code number, which was conventionally engraved using laser marking technology, using an ultraviolet laser exposure device built into the projection exposure device. The difference is that it is printed.

Furthermore, the present invention has a difference in that the encoded and printed ROM code number is recognized by an infrared reading device built into the same exposure device, and exposure is automatically performed using a mask corresponding to the ROM code number.

[Means to solve the problem]

The projection exposure apparatus of the present invention has a function of printing encoded information in a partial area of a semiconductor wafer coated with photoresist, a function of reading the code, and a function of automatically selecting a mask corresponding to the code. This mask has the function of transferring and forming a device pattern onto the photoresist coated on the wafer.

〔Example〕 Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a diagram of a device configuration of an embodiment of the present invention, Fig. 2 is a schematic diagram explaining a code printing method used in an embodiment, and Fig. 3 is a schematic diagram explaining a code reading method used in an embodiment. It is.

First, the configuration of the apparatus shown in FIG. 1 will be explained. This apparatus includes a loader cassette 2 that stores the wafer X1a coated with photoresist, and a loader cassette 7 that transports the wafer 1a from the loader cassette 2 to the projection exposure chamber 7 where exposure processing is performed. A transfer arm 4 that prints a code on a partial area of the wafer 1a that has been coated with photoresist, a code printing unit 5 that prints a code on a partial area of the wafer 1a that has been coated with photoresist, a code reading unit 6 that reads the formed code, and a projection exposure chamber 7 that transports the wafer 1b that has been exposed. It is composed of an unloader cassette 3 from which the unloader is carried out.

Next, the exposure method for each wafer process will be explained with reference to FIG.

First, the exposure of the wafer for mask ROM switching will be explained. The wafer 1a, which has been coated with photoresist and is set in the low-goo cassette 2, is transported by the transport arm 4 to the projection exposure chamber 7, where it is used to print a code corresponding to the zero-order ROM code set on the wafer stage 8. , the wafer stage 8 moves to the bottom of the code printing unit 5, and the code is printed.The 0th order wafer 1a returns to its normal position and starts the 0th order exposure process, in which projection exposure is performed using a mask corresponding to the ROM code. The completed wafer lb is transferred from the projection exposure chamber 7 to the unloader cassette 3 by the transfer arm 4.

Next, a description will be given of the process in which the mask ROM switching has been completed. Here, loading and unloading into and out of the projection exposure chamber 7 is the same operation as described above, so the explanation will be omitted. maskRO
For wafers for which M switching has been completed, maskROM
Since the code formed in the PR at the time of switching is attached, the photoresist-coated wafer 1a that has been transported and set on the wafer stage 8 moves to the bottom of the code reading section 6 to read the ROM code, and the code is read. The apparatus automatically selects a mask corresponding to the zero-order ROM code and performs projection exposure.

Next, the code printing method will be explained with reference to FIG. As shown in FIG. 2, an ultraviolet laser 12 irradiated by an ultraviolet laser generator 11 prints a bar code several μm wide on a partial area of a coated wafer 1a set on a wafer stage 8 that can move in the direction of the arrow. 10 is formed.

Finally, the code reading method will be explained with reference to FIG. A barcode code 10 such as an oxide film has already been formed on the wafer for which maskROM switching has been completed. This code is hit by an infrared laser 15 emitted from an infrared laser generator 16, and by moving the wafer 1b in the direction of the arrow, a reflected wave 17 is generated at the stepped portion of the code pattern. The width of this reflected wave 17 is detected by a reflected wave detection device 18 and the code is read.

〔Effect of the invention〕

As explained above, the present invention can automatically perform exposure work for ROM code switching products such as mask ROMs that are manufactured in small quantities and in a wide variety of products, eliminate visual confirmation errors, and eliminate the work of distributing wafers for each ROM code. This has the effect of increasing line throughput.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of an apparatus according to an embodiment of the present invention. Fig. 2 is a schematic diagram explaining a code printing method used in an embodiment. Fig. 3 is a schematic diagram explaining a code reading method used in an embodiment. It is. 1a... Photoresist coated wafer, 1b-
...Exposed wafer, 2...Loader cassette,
3... Unloader cassette, 4-... Transfer arm,
5... Code printing section, 6... Code reading section, 7...
・Projection exposure chamber, 8...Wafer stage, 11...
Ultraviolet laser generator, 12... Ultraviolet laser. 15...Infrared laser, 16...-Infrared laser generator, 17...Reflected wave, 18...Reflected wave detector.

Claims (1)

[Claims] A projection exposure apparatus used in the photolithography process of semiconductor manufacturing has a function of printing a code on a partial area of a semiconductor wafer, a function of recognizing the code, and a function of automatically selecting a mask corresponding to the code. 1. A projection exposure apparatus having a function of performing projection exposure using a mask.