JP2002184672A - Formation method of positioning mark for photomask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a mix-and-match method further accurately. SOLUTION: First, A part alignment marks 81, 82 as a positioning mark for a batch aligner and B part alignment marks 83a, 83b as a positioning mark for a reducing projection aligner are exposed and are formed at a prescribed position on a wafer 4 in a first photolithographic process. From the next photolithographic process, either the A part alignment marks 81, 82 or the B part alignment marks 83a, 83b is used, as required. Thereby, exposure to the wafer 4 becomes possible by carrying out a mix-and-match method further accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming an alignment mark of a photomask used in a photolithography process and a method of manufacturing a semiconductor device using the mark.

[0002]

2. Description of the Related Art FIG. 4 shows a general photolithography process in a semiconductor device manufacturing process. In the figure,
Reference numeral 1 denotes a semiconductor substrate, on which an insulating film 2 of SiO2 or the like is formed, and in a step (a) of the drawing, a photoresist 3 is uniformly applied on the insulating film 2 by a spin coater or the like. Next, in the step (b), a predetermined pattern is exposed on the photoresist 3, and in the step (c), the photoresist 3 exposed to the predetermined pattern is developed. Then
In the step (d), the insulating film 2 is etched using the photoresist 3 as a mask, and in the step (e), the etched photoresist 3 is removed.

When the pattern exposure step (b) is performed, a batch exposure apparatus or a reduction projection exposure apparatus called a stepper is used. These exposure apparatuses have advantages and disadvantages. FIG. 5 shows a mirror projection exposure apparatus (MirrorProjection Aligne) which is one of the batch exposure apparatuses.
r) Brief description.

[0004] The mirror projection exposure apparatus uses a photoresist 3
The light is projected from the light source 6 to the photomask 5 on the wafer 4 coated with, and a pattern of the same size as that of the photomask 5 is exposed on the wafer 4. FIG.
Is a plan view of the wafer 4 on which a predetermined pattern 7 and an alignment mark 8 are formed.

[0005] In the case of using the one-shot exposure apparatus as described above, the accuracy as a guide of the resolution is as coarse as about 10 µm.
It has the feature of excellent workability due to batch exposure.

FIG. 7 shows a schematic configuration of a stepper apparatus which is a reduction projection exposure apparatus. In this stepper device, a condensing lens 9 is disposed between a wafer 4 and a photomask 5 on which a photoresist 3 is applied, and light from a light source 6 is applied to reduce exposure. A predetermined pattern 7 and an alignment mark 8 are formed on the wafer 4 as shown in FIG. Although FIG. 8 shows one unit of the shot,
A pattern 7 and an alignment mark 8 in one shot are formed on the entire surface of the wafer 4 by a step-and-repeat method.

When the above-described reduced projection exposure apparatus is used, the reduction exposure is repeatedly performed at predetermined intervals, so that the workability is inferior to that of the above-described batch exposure apparatus, but the accuracy is about 1 μm and the fine exposure is possible. Are better.

FIG. 9 shows a more detailed configuration of the wafer 4 exposed by the batch exposure apparatus. Wafer 4
A pattern 7 is collectively exposed on the upper side, and two alignment marks 8 are formed on the left and right of the center of the wafer 4. The left and right alignment marks 8 have mirror-symmetrical shapes, and are composed of a first alignment mark 8a on the left and a second alignment mark 8b on the right.

FIGS. 10 and 11 show a more detailed structure of the wafer 4 exposed by the above-mentioned reduction projection exposure apparatus. A predetermined pattern 7 is formed on the wafer 4 by a step-and-repeat method. Further, as shown in FIG.
L1 to Ln in the vertical direction at the upper right of 0
It is constituted by L1 to Ln, which are long at the lower left of 0 in the horizontal direction, and have predetermined positions and sizes, respectively.

[0010]

The alignment marks 8 exposed and formed by the above-described conventional batch exposure apparatus and reduction exposure apparatus have different positions, sizes, shapes, and the like. For this reason, when manufacturing a semiconductor device, either the batch exposure apparatus or the reduction exposure apparatus determined first must be used due to the restriction of the mark 8. That is, for example, in a manufacturing process of a semiconductor device in which a fine pattern and a coarse pattern need to be formed at the same time, it is necessary to process a coarse pattern in an intermediate process because exposing the fine pattern is a necessary condition in production. However, since the alignment mark 8 is formed only for the reduction exposure device, a stepper device must be used. In such a case, there is a problem in that work efficiency is poor as a whole because a reduced exposure is repeatedly performed by a step-and-repeat method to process a coarse pattern.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method of forming an alignment mark for alignment in a manufacturing process of a semiconductor device which requires a fine pattern and a coarse pattern simultaneously. Method of forming alignment mark of photomask using a collective exposure apparatus and a reduced exposure apparatus together so that a so-called mix-and-match method can be used more accurately, and manufacture of a semiconductor device using the mark It is intended to provide a method.

[0012]

According to the present invention, there is provided a method of forming a positioning mark of a photomask, comprising mixing a photoresist layer applied on a semiconductor substrate by using a 1: 1 type batch exposure apparatus and a reduction projection exposure apparatus together. In a method for forming a positioning mark of a photomask used in a photolithography process of exposing and developing by an and match method, in a first photolithography process, a positioning mark for a batch exposure apparatus and a positioning mark for a reduced projection exposure apparatus Are formed on the semiconductor substrate.

Further, a method of manufacturing a semiconductor device according to the present invention
It has an initial photolithography step of forming alignment marks for the batch exposure apparatus and alignment marks for the reduced projection exposure apparatus on the semiconductor substrate. From the next photolithography step, the pattern resolution, alignment accuracy, etc. A batch exposure apparatus or a reduced projection exposure apparatus is used depending on the degree of process demand, and alignment between the layers is performed using one of the alignment marks formed in the first photolithography step. is there.

[0014]

According to the method for forming the alignment mark of the photomask of the present invention, the alignment mark for the batch exposure apparatus and the alignment mark for the reduced projection exposure apparatus are formed on the semiconductor substrate in the first photolithography step. From the next photolithography step, the mix-and-match method can be performed accurately using any alignment mark (alignment mark) as necessary.

In addition, by performing the semiconductor device manufacturing process by using any one of the above-mentioned alignment marks, exposure to a semiconductor substrate on which a fine pattern and a coarse pattern are mixed can be performed only by a reduced projection exposure apparatus such as a stepper apparatus. Without performing the above, a batch exposure apparatus can be used for exposure of a coarse pattern, so that the production efficiency of a semiconductor device can be improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, and is a plan view of a wafer for explaining an alignment mark forming method in the case of one chip / 1 reticle. This embodiment is characterized in that both alignment marks for the batch exposure apparatus and alignment marks for the reduced projection exposure apparatus are formed on the wafer 4 in the first photolithography step. That is, in the figure, a photo resist (not shown) is uniformly formed on the wafer 4.
Is applied, and a predetermined pattern 7 is applied to the wafer 4.
And alignment marks 81 and 82 for a reduced projection exposure apparatus (referred to as A section alignment marks) are formed by exposure using a reduced projection exposure apparatus such as a stepper apparatus.

The above-mentioned pattern 7 is a relatively fine pattern. The fine pattern 7 and the A-section alignment marks 81 and 82 are formed on the wafer 4 by a step-and-repeat method using the reference shot 10 as one unit. The entire surface is exposed as shown in FIG. Next, wafer 4
A pair of collective exposure apparatus alignment marks (referred to as B section alignment marks) 83a and 83b are exposed and formed in the vicinity of both left and right ends by the above-mentioned reduced projection exposure apparatus.

Further, the B portion alignment marks 83a, 8
3b mutual formation order, A part alignment marks 81, 8
The order of forming the alignment marks 2 and B and the order of forming the alignment marks 83a and 83b, or the pattern 7 and the order of forming the alignment marks are not particularly limited. It may be formed.

By forming the A-part alignment marks 81 and 82 and the B-part alignment marks 83a and 83b on the wafer 4 in the first photolithography process as described above, a coarse pattern is formed in the next photolithography process. If exposure is required, a B-section alignment mark 83a, which is a positioning mark for a batch exposure apparatus,
83b can be used, and the mix-and-match method can be performed accurately. By incorporating this into a manufacturing process of a semiconductor device having a plurality of photolithography processes, the production efficiency can be improved.

FIG. 2 shows a second embodiment of the present invention.
This embodiment shows an alignment mark forming method for a 4-chip / 1-reticle. That is,
Four predetermined patterns 7 are formed in one reference shot 10, and a pair of A-part alignment marks 81 and 82 at the upper right and lower left in the vertical direction are formed in the reference shot 10 by a reduced projection exposure apparatus such as a stepper. Thus, the entire surface of the wafer 4 is exposed and formed in a step-and-repeat manner.

In this embodiment, the order of formation is arbitrary, but a pair of left and right B portion alignment marks 83a and 83b are exposed and formed with respect to the center of the wafer 4 by the above-described reduction projection exposure apparatus. . Also in this case, it is preferable to form the pattern 7 in the shot 100 similarly to the first embodiment, since the wafer 4 can be effectively used. FIG. 3 shows only the B-part alignment mark 83b on the right side, but the B-part alignment mark 83a is exposed and formed on the left side of the wafer 4 in mirror symmetry with the B-part alignment mark 83b. It is. In the above embodiment, the patterns and the alignment marks in the case of 1 chip / 1 reticle and 4 chips / 1 reticle have been described, but it is needless to say that the present invention can be applied to other plural chips / 1 reticle. No.

[0022]

As described above, according to the present invention, in the first photolithography step, the alignment mark for the batch exposure apparatus and the alignment mark for the reduced projection exposure apparatus are formed on the semiconductor substrate. Therefore, from the next photolithography step, the mix-and-match method can be performed accurately using any alignment mark as necessary. In addition, by performing the manufacturing process of the semiconductor device by properly using any one of the above-described alignment marks, the exposure to the semiconductor substrate in which the fine pattern and the coarse pattern are mixed can be performed only by the reduced projection exposure apparatus such as the stepper apparatus. In addition, since a batch exposure apparatus can be used for exposure of a coarse pattern, there is an effect that the production efficiency of a semiconductor device can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a wafer showing a first embodiment of the present invention.

FIG. 2 is a plan view of a wafer showing a second embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a configuration in a shot in FIG. 2;

FIG. 4 is an explanatory diagram of a photolithography process in a manufacturing process of the semiconductor device.

FIG. 5 is an explanatory diagram when a pattern is exposed on a wafer using a batch exposure apparatus.

FIG. 6 is a plan view of a wafer exposed by the batch exposure apparatus.

FIG. 7 is an explanatory diagram when a pattern is exposed on a wafer using a reduction projection exposure apparatus such as a stepper.

FIG. 8 is a plan view of a wafer exposed by the reduction projection exposure apparatus.

FIG. 9 is a diagram illustrating an example of forming an alignment mark when a batch exposure apparatus is used.

FIG. 10 is a diagram illustrating an example of forming an alignment mark when a reduction projection exposure apparatus is used.

FIG. 11 is an enlarged view of the alignment mark of FIG. 10;

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 insulating film 3 photoresist 4 wafer 5 photomask 6 light source 7 pattern 8 alignment mark 8a first alignment mark 8b second alignment mark 9 condensing lens 10 reference shot 81, 82 A section alignment mark 83a, 83b B section 100 alignment marks

Claims (3)

[Claims] 1. A photomask used in a photolithography step of exposing and developing a photoresist layer applied on a semiconductor substrate by a mix-and-match method using both a 1: 1 batch exposure apparatus and a reduction projection exposure apparatus. A photomask, wherein both the alignment mark for the batch exposure apparatus and the alignment mark for the reduced projection exposure apparatus are formed on the semiconductor substrate in the first photolithography step. Method of forming alignment marks. 2. The alignment mark formation position is formed near the left and right ends of the semiconductor substrate for the batch exposure apparatus alignment mark, and the remaining position of the semiconductor substrate for the reduced projection exposure apparatus alignment mark. 2. The method according to claim 1, wherein the alignment mark is formed in an effective area of the photomask. 3. An image forming apparatus according to claim 1, further comprising: a first photolithography step for forming both the alignment mark for the batch exposure apparatus and the alignment mark for the reduced projection exposure apparatus on the semiconductor substrate. ,
Use a batch exposure apparatus or a reduced projection exposure apparatus depending on the process requirements such as alignment accuracy, and perform alignment between each layer using one of the alignment marks formed in the first photolithography process. A method for manufacturing a semiconductor device.