KR20000045423A - Method for aligning wafer - Google Patents

Abstract

PURPOSE: A method for aligning a wafer is provided to improve an alignment accuracy by performing an exposure and an alignment of a wafer at the same time. CONSTITUTION: In a method for aligning a wafer, pluralities of wafers(3,5) are mounted on a wafer stage(1) of an exposure equipment having an exposure lens(7) and an alignment module(9). The exposure lens(7) and the alignment module(9) are set so as to be directed into the same portion of each wafer thus mounted. During scanning the wafer stage(1) in order to expose a die of a wafer, the alignment module aligns the same die of another wafer so as to perform an exposure and an alignment of a wafer at the same time.

Description

Alignment method of wafer in exposure equipment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer alignment method in an exposure apparatus, and in particular, by simultaneously exposing a wafer and performing a wafer alignment together, it is possible to improve the manufacturing accuracy of the semiconductor device by improving the alignment accuracy and reducing the time used for the lithography process. The present invention relates to a wafer alignment method in an exposure apparatus.

The wafer exposure process according to the prior art is carried out in the following process sequence.

First, the pre-alignment process on the pre-alignment module,

Second, a fine alignment process on the wafer stage,

Third, a wafer exposure process on the wafer stage is performed.

In the most widely used scanning type exposure equipment, the highest yielding equipment is processing about 50 wafers per hour. However, the time taken to align the wafer is a large portion that accounts for about 30% of the total wafer processing time.

On the other hand, the alignment of the wafer is divided into two types according to the measurement method, there is a method of selecting a limited number of die (read) to obtain the alignment information of the entire wafer, for example, a global alignment (global alignment) method.

Secondly, there is a method of obtaining information by measuring the degree of alignment of all dies of a wafer, that is, a die by die alignment method.

Of course, the latter method can obtain more accurate wafer alignment information, but there is a disadvantage in that it takes about 4 to 6 times more time than the global alignment method. In global alignment method is used.

Accordingly, the present invention allows the exposure to be performed simultaneously with the alignment of the wafer, not the order of exposing the wafer after the wafer alignment, in consideration of the problems in the prior art, so that the yield problem and global alignment in the manufacturing process, which is a problem of the general alignment method, are performed. It is an object of the present invention to provide a wafer alignment method in an exposure apparatus that can simultaneously solve inaccuracies in legal data.

1 is a schematic diagram showing the structure of an exposure apparatus used in accordance with the method of the present invention

2 is a schematic view of an exposure apparatus showing another embodiment of the present invention;

<Explanation of symbols for the main parts of the drawings>

1: wafer stage 3,5: wafer

7,13: exposure lens 9,15: alignment module

Wafer alignment method in the exposure apparatus according to the present invention for achieving the above object,

A plurality of wafers may be mounted on top of a wafer stage of an exposure apparatus including an exposure lens and an alignment module, and the exposure lens and the alignment module of the exposure apparatus are set to face the same portion of each mounted wafer, and one wafer While scanning the wafer stage to expose the die of the alignment module, the alignment module is configured to align the same die of the other wafer so that the exposure and alignment of the wafer can be performed simultaneously.

Hereinafter, an embodiment of a wafer alignment method in an exposure apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

For reference, the core of a general exposure apparatus is divided into a projection optic and an alignment module.

The two portions are fixed to each other so that the exposure lens performs exposure after the alignment unit completes wafer alignment. In the present invention, the two parts are fixed but used at the same time.

1 is a schematic diagram showing the structure of an exposure apparatus used in accordance with the method of the present invention.

Referring to the drawings, the wafer stage 1 is designed so that two wafers 3 and 5 can be mounted, and the exposure lens 7 and the alignment module 9 are each wafers 3 and 5. It is set to face the same part of).

Thus, the alignment module 9 may align the same die of the other wafer 5 while scanning the wafer stage 1 to expose the die of the one wafer 3. That is, both exposure and alignment are performed by scanning a specific portion of the wafer.

By simultaneously exposing and aligning one side of the wafer 3 on the same principle as described above, the manufacturing process yield can be improved by about 30% or more by reducing the time required for conventional wafer alignment, and it is not a global alignment of the conventional sampling method. By performing die by die alignment, the degree of alignment of the wafer can be greatly contributed.

In this case, the case where two wafers 3 and 5 are mounted on the wafer stage 1 is illustrated, but the number of wafers to be mounted may be two or more, for example, two to four.

On the other hand, Figure 2 is a schematic diagram of an exposure apparatus showing another embodiment of the present invention.

As shown in the figure, a method of simultaneously exposing and aligning a predetermined wafer 11 is also possible.

This briefly performs a global alignment to get the overall information of the wafer. It then measures the alignment of adjacent dies (B dies) while the wafer stage is scanning to expose a particular die (A die), and reflects that information when exposing the dies (B dies). The above method can be expected to improve the degree of alignment by mixing the die by die alignment method with the existing global alignment method.

In the above-described method of the present invention, the alignment mark in the wafer alignment may be a Chevron method, a grating method, a field image method, etc. using a laser light source, a laser or a mercury lamp is used as the exposure light source.

As described above, the present invention can improve the alignment accuracy by performing exposure and alignment on the wafer at the same time, thereby improving the alignment accuracy, and significantly reducing the time required for the semiconductor lithography process. Yield can be improved.

Claims (5)

A plurality of wafers may be mounted on top of a wafer stage of an exposure apparatus including an exposure lens and an alignment module, and the exposure lens and the alignment module of the exposure apparatus are set to face the same portion of each mounted wafer, and one wafer While scanning the wafer stage to expose the die of the wafer, the alignment module allows the same die of the other wafer to be aligned to simultaneously perform exposure and alignment of the wafer. The method of claim 1, A wafer alignment method in an exposure apparatus, comprising mounting two to four wafers on a wafer stage while simultaneously performing exposure and alignment. The method of claim 1, The alignment mark when the wafer is aligned, the wafer alignment method in the exposure apparatus comprising a Chevron method, a grating method, a field image method using a laser light source. The method of claim 1, And a laser or a mercury lamp as the exposure light source. The method of claim 1, And mounting one wafer on the wafer stage to simultaneously align adjacent dies during exposure.