JPH05341499A - Reticle for stepper - Google Patents

Abstract

PURPOSE:To expose an alignment mark onto a wafer without causing a misalignment and crushing, and to enhance the alignment accuracy. CONSTITUTION:In the reticle for a stepper, by arranging protective patterns 10, 11 in an alignment mark 4 arranged in a scribe line area 3 in the periphery of a main body chip area 1, the alignment mark 4 can be arranged in the scribe line area 3 in the periphery of the main body chip area 1, and the protective patterns 10, 11 are provided, by which at the time of exposure, the alignment mark is not crushed, a throughput of a design of the reticle for the stepper is improved, the alignment accuracy is improved, and the improvement of the non-defective unit yield can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reticle for a reduction projection exposure apparatus at the time of exposure in the step of forming an LSI pattern on a wafer using a resist or the like.

[0002]

2. Description of the Related Art In recent years, the degree of integration of semiconductors has dramatically increased, and it has become mainstream to form a fine pattern on a wafer by using a reduction projection exposure apparatus called a stepper.

Particularly, since the area of the chip itself has recently increased and the total number of chips on the reticle tends to decrease, the area of the scribe line portion also tends to decrease. Furthermore, it is necessary to arrange the alignment mark in a location where adjacent chips are not affected by exposure while observing the arrangement rule of the alignment mark. Depending on the location of the alignment mark, the yield of non-defective products is strong, which is a serious problem.

A conventional reticle for a reduction projection exposure apparatus will be described below with reference to the drawings.

4 and 5 are plan views showing the structure of a conventional reticle for a reduction projection exposure apparatus. The conventional reticle for a reduction projection exposure apparatus shown in FIG. 4 is an example of a 9-chip configuration, and the reticle for a reduction projection exposure apparatus shown in FIG. 5 is an example of a 4-chip configuration. The conventional reticle for reduction projection exposure apparatus is composed of a main body chip region 1, a PCM region 2, a scribe line region 3 and an alignment mark 4. The PCM in the PCM area 2 is Process Cont
Abbreviation for rol Monitor.

The conventional reticle for a reduction projection exposure apparatus having the above-described structure is used to form a pattern by exposure using a stepper or the like.

[0007]

However, the above-mentioned conventional structure has the following problems. Figure 4 above
When the number of chips is 9, as shown in FIG. 5, there are many scribe line regions 3, and therefore the alignment marks 4 can be easily arranged even if the arrangement rule of the alignment marks 4 and the influence of exposure on adjacent chips are taken into consideration. It However, in recent years, the location of the alignment marks has been decreasing due to the increase in the size of the main body chip and the increase in the number of the various alignment marks, and there is a problem especially when the number of main body chips in the main body chip area is small, for example, four. ..

A description will be given below with reference to the drawings. Figure 6
FIG. 6 is a plan view showing a pattern state on a wafer when exposed using the reticle for the conventional reduction projection exposure apparatus shown in FIG. An exposure area 6 and a PCM area 7 for one shot are formed on the wafer 5.

FIG. 7 is an enlarged plan view of an alignment mark portion on the wafer shown in FIG.

As in the reticle for the reduction projection exposure apparatus shown in FIG. 5, when the number of the main body chip area 1 is a small number on the reticle, the alignment mark 4 is arranged on the scribe line area 3 around the main body chip area 1 in the case of four reticle. Then, when the wafer 5 is exposed as shown in FIG. 6, the alignment mark 9 formed on the scribe line 8 on the wafer 5 as shown in an enlarged view of the alignment mark portion shown in FIG.
Is displaced and crushed. Further, there is a problem that the non-alignment due to the collapse of the alignment mark 9 due to the adjacent shots and the misalignment due to the collapse of the alignment mark 9 due to the shift shot affect the yield of non-defective products.

The present invention solves the above-mentioned problems of the prior art. It is possible to arrange an alignment mark also on a scribe line around the main body chip area of a reticle for a reduction projection exposure apparatus, and at the same time, for a reticle for a reduction projection exposure apparatus. The purpose is to improve design throughput and yield of non-defective products.

[0012]

In order to solve the above problems, a reticle for a reduction projection exposure apparatus of the present invention has the following structure. That is, at least one main body chip region, a PCM region, and a scribe line region between the main body chip regions are provided in the reticle, and the alignment mark is provided in the scribe line region and is symmetrical about the Y axis with respect to the alignment mark. First placed in position
And a second protection pattern arranged at a position moved by the shift shot by the PCM area.

[0013]

With the above structure, the protection pattern is arranged at a position symmetrical to the X-axis and the Y-axis with respect to the alignment mark arranged on the scribe line around the main body chip region. In addition, P from the position where the alignment mark is placed to the Y-axis
By arranging the CMs at positions corresponding to the shift shots by the CM, it becomes possible to arrange the alignment marks on the periphery in the main body chip area of the reticle for the reduction projection exposure apparatus, and it becomes possible to perform alignment and the patterns may be displaced and crushed. Disappear.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a reticle for a reduction projection exposure apparatus according to an embodiment of the present invention.

The reticle for a reduction projection exposure apparatus shown in FIG. 1 has a main body chip region 1 (4 chips) arranged on the reticle, a PCM region 2, and a scribe line region 3.
Alignment mark 4, first protection pattern 10 and PC symmetrical with respect to the alignment mark 4 in the Y-axis
The second protection pattern 11 is moved by the shift shot by M.

First, the placement position of the alignment mark 4 is set according to the placement rule. If the arranged position is on the periphery of the main body chip region, the first protection pattern 10 (alignment mark and protection pattern are overlapped and exposed to form one alignment mark) at symmetrical positions with respect to the X axis and the Y axis. Pattern).

Next, the PCM area 2 is shot (one exposure).
By doing so, when the shift of the main body chip area 1 is different from the shot size of the main body chip area 1, the second position is moved from the alignment mark 4 by the shift shot.
The protection pattern 11 of is arranged.

A case will be described in which exposure is performed using the reticle for a reduction projection exposure apparatus in which the alignment mark 4 and the protection patterns 10 and 11 are arranged as described above.

FIG. 2 is a plan view showing the state of the wafer when it is exposed using the reticle for the reduction projection exposure apparatus shown in FIG. The exposure area 6 for one shot is formed on the wafer 5.
And a PCM area 7 is formed. FIG. 3 is an enlarged plan view of an alignment mark portion on the wafer shown in FIG.

When the wafer 5 is exposed by using the reticle shown in FIG. 1, the alignment mark 12 can be formed on the scribe line 8 on the wafer 5 by exposure without crushing it, as shown in FIG. ..

As described above, according to this embodiment, by disposing the first protection pattern 10 and the second protection pattern 11 as protection patterns for the alignment mark 4, the scribe line area 3 around the main body chip area 1 is arranged. When the alignment mark 4 can be arranged on the upper side of the wafer 5 and the alignment mark 12 is formed on the wafer 5, the alignment mark 12 does not collapse.

As described above, the alignment marks can be arranged also on the scribe lines around the main body chip area, the throughput of designing the reticle for the reduced projection exposure apparatus is improved, the alignment accuracy is improved, and the yield of non-defective products is improved. ..

[0024]

As described above, according to the present invention, by arranging the protection pattern of the alignment mark, it becomes possible to arrange the alignment mark on the reticle even on the peripheral scribe line of the main body chip area. It is possible to realize an excellent reticle for a reduction projection exposure apparatus capable of improving the throughput of the design of the working reticle and improving the alignment accuracy, and improving the yield of non-defective products.

[Brief description of drawings]

FIG. 1 is a plan view showing the configuration of a reticle for a reduction projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a wafer when exposed using a reticle for a reduction projection exposure apparatus according to an embodiment of the present invention.

FIG. 3 is an enlarged plan view of an alignment mark portion on a wafer when exposed using a reticle for a reduction projection exposure apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing the configuration of a reticle for a conventional reduction projection exposure apparatus (9
Top view showing chip configuration)

FIG. 5: Structure of reticle for conventional reduction projection exposure apparatus (4
Top view showing chip configuration)

FIG. 6 is a plan view of a wafer when exposed using a reticle for a conventional reduction projection exposure apparatus.

FIG. 7 is an enlarged plan view of an alignment mark portion on a wafer when exposed using a reticle for a conventional reduction projection exposure apparatus.

[Explanation of symbols]

 1 Main Chip Area 2 PCM Area 3 Scribe Line Area 4 Alignment Mark 5 Wafer 6 Exposure Area for One Shot 7 PCM Area on Wafer 8 Scribing Line on Wafer 9 Alignment Mark 10 First Protective Pattern 11 Second Protective Pattern 12 Alignment mark

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area H01L 21/027

Claims (1)

[Claims] 1. A reticle having at least one main body chip region, a PCM region, and a scribe line region between the main body chip regions, wherein the scribe line region has an alignment mark and a Y-axis with respect to the alignment mark. The first protection pattern arranged symmetrically with respect to
A reticle for a reduction projection exposure apparatus, comprising a second protection pattern arranged at a position moved by the shift shot by the PCM area.