JPH01235954A - Reticle for lithography and reticle pattern transfer method - Google Patents

Abstract

PURPOSE:To execute a reticle pattern transfer by a single reticle and a single printing process by forming an index pattern in other area than a main pattern area. CONSTITUTION:A reticle 201 consists of a main pattern area 203 and other surrounding area. In the surrounding area, an alignment target pattern 207 for pre-alignment use being an index pattern, a reticle cover 212 and a scribe 214 are formed. The reticle cover 212 is a pattern for exerting no influence of an exposing light beam on an adjacent frame in the course of exposing one frame on a wafer, and the scribe 214 is a pattern for prescribing a cutting plane line (or a cutting margin) for cutting finally. In such a way, the main pattern and the index pattern can be printed simultaneously by a single reticle and a single printing process.

Description

[Detailed Description of the Invention] [Summary] Regarding a reticle for lithography of a semiconductor device, the object of the present invention is to provide a reticle for lithography of a semiconductor device that can perform reticle pattern transfer with a single reticle. The reticle for use in the present invention is configured such that an index pattern is formed in an area other than the main pattern area.

(Industrial Application Field) The present invention relates to a reticle for lithography of a semiconductor device and a reticle pattern transfer method using the reticle.

[Conventional technology]

In lithography for manufacturing semiconductor devices, a reticle is used to print a main pattern (the pattern of the semiconductor device itself) and various index patterns (
Transfer (print) process monitor pattern, design monitor pattern, alignment target pattern, etc.
In this case, conventionally, a main pattern reticle and an index pattern reticle were separately manufactured, and each was printed in a separate process.

As a conventional example, a reticle used and a printing procedure will be described in the case where a main pattern of a semiconductor device itself and an index pattern as an alignment target are printed on a wafer by a step-and-repeat operation. Figure 3(a)~
In (d), (a) and (b) respectively show the main pattern reticle 301, index, and pattern reticle 311, and (C) and (d) show the wafer 320.
A state in which a main pattern "F" is printed on the top, and a state in which an index pattern "±" is printed after the main pattern is shown.

Two types of reticles are separately prepared as described above. The main pattern reticle 301 has a main pattern 1-F" formed in the main pattern area 303 at the center by Cr vapor deposition, etc., and an area 305 other than the main pattern area 303.
No pattern is formed in the area (hereinafter abbreviated as "outer area" in some cases). A part of the surrounding area 305 is used for handling such as mounting a reticle on a stepper (reduction projection exposure apparatus). The index pattern reticle 311 has the same configuration as the main pattern reticle except that an index pattern "+" is formed in the main pattern area 313 instead of the main pattern.

The baking process consists of two separate steps as follows.In the first step, only the main pattern "F" is printed in the following procedure. First, the main pattern reticle 301 is attached to the stepper. Exposure by the stepper is started from the leftmost frame of the top row of the wafer 320 in FIG. 3(C) (the area on the wafer that is printed in one exposure corresponding to the main pattern area of the reticle) Repeat sequentially to the right along arrow 3 (C
) to print in a mosaic or grid pattern). At that time, the frame 329 on which the index pattern is to be burned later
Then, leave it in a blank state without exposing it.

In the second step, only the index pattern "+" is burned out. First, from the stepper to the main pattern reticle 30
1 and replace it with the index pattern reticle 311.
Attach it to the stepper. The stepper is moved by the required displacement amount in the X direction and the X direction, and the index pattern "10" is printed by exposing only the unexposed frame 329 that was left blank in the first step (Fig. 3 (d)). .

As described above, conventional reticles and reticle pattern transfer methods have problems such as high reticle production costs because two or more reticles are required, and low productivity because the printing process requires two or more steps including reticle exchange operations. was there.

[Problems to be Solved by the Invention] The present invention provides a reticle for lithography of a semiconductor device that can perform reticle pattern transfer with a single reticle and a single printing process, and a reticle pattern transfer method using this reticle. The purpose is to

[Means for Solving the Problem] According to the present invention, the above object is to provide a lithography reticle for a semiconductor device, characterized in that an index pattern is formed in an area other than the main pattern area. Accomplished by a reticle.

The above object is also achieved by a reticle pattern transfer method characterized by including a step of simultaneously printing a main pattern and an index pattern using the above reticle.

(Function) According to the lithography reticle of the present invention, since a single reticle has a main pattern and an index pattern, both patterns can be printed simultaneously in one exposure without changing the reticle.

Further, according to the reticle pattern transfer method of the present invention, the reticle pattern is transferred in a single printing process by simultaneously printing the main pattern and the index pattern at necessary locations on the wafer or master mask using the above reticle. Hereinafter, the present invention will be explained in more detail by way of examples with reference to the drawings.

〔Example〕

FIG. 1(a) shows an example of a lithography reticle according to the present invention.

The reticle 101 consists of a main pattern area 103 and other areas (surrounding area) 105. Main pattern area 1
03, a main pattern 1F" is formed.

In the surrounding area 105, index patterns "+" are formed on both the left and right sides of the main pattern area 103, respectively.

FIGS. 1(b) to 1(e) show an example of a printing process in which a reticle pattern is transferred onto a wafer using the reticle 101 shown in FIG. 1(a).

The reticle 101 is attached to a stepper (not shown).

The stepper moves the reticle 101 into the potato pattern area 103.
The outer surrounding areas 105 on both the upper and lower sides of the main pattern area 103 are maintained in a state where they can be irradiated with exposure light as needed, similar to the main pattern area 103.

The wafer 12 in FIG. 1(b) is exposed by a stepper.
Start from the leftmost frame of the top row of 0. At this time, play 1 (aperture) of the stepper is set to an aperture such that only the main pattern area 103 of the reticle 101 is irradiated with the exposure light beam.
” degree. In other words, when exposed in this state, the first
Only the main pattern "F" in the main pattern area 103 indicated by diagonal lines in FIG. 3(C) is printed onto the wafer. In this open state, exposure is sequentially repeated to the right along arrow (Also move in the X direction if necessary). Thereafter, the main pattern "F" is printed in all frames up to the third row on the wafer 120 by the same step-and-repeat operation. Before starting the exposure of the fourth row, the aperture of the stepper blade is enlarged so that the main pattern area 103 and a part of the outer area 105 of the reticle are
The aperture is set so that the exposure light beam is irradiated onto the 5A. When exposure is performed at the position of the frame 123A at the left end of the fourth row in this open state, the main pattern 1F of the main pattern area f area 103 of the reticle 101 is printed on the frame 123A, and at the same time, the reticle is printed on the frame 125A on the right. 10
Index pattern r of a part 105A of the surrounding area 105 of
+ is burned in. Next, the exposure position is moved to the right by two frames, that is, to frame 123P. Adjust the aperture of the stepper blade to the reticle 101 as before.
The exposure light beam is reduced so that only the main pattern area 103 (the shaded area in FIG. 1(C)) is irradiated with the exposure light. Exposure is carried out sequentially to the right in this open state, and the main pattern rF is formed in the frames from frame 123P to frame 123Q.
Burn J. Next, the exposure position is moved to the right by two frames, that is, to frame 123B at the right end of the fourth row. At this stage, frame 125B is in a non-hazy state. By enlarging the aperture of the stepper blade in the opposite direction to the left end of the fourth row, the main pattern area 103 of the reticle 101 and a part 105B of the outer area 105 are shown in FIG. 1(e). so that the exposure light is irradiated on both sides. When exposure is performed at the position of the frame 123B at the right end of the fourth row in this open state, the main pattern l'FJ of the main pattern area 103 of the reticle 101 is printed on the frame 123B, and at the same time, the reticle is printed on the adjacent frame 125B on the left. 101
An index pattern "+" in a part 105B of the outer area is printed. The aperture of the stepper blade is adjusted to the main pattern area 103 (11th
The size is reduced so that only the shaded area (1(C)) is irradiated with the exposure light. Thereafter, a step-and-repeat operation is performed in the same manner as in the first column (top column) to the third column, and the main pattern "F" is printed in each frame of the fifth and sixth columns, thereby completing the printing process.

As described above, the main pattern and the index pattern are printed in a predetermined arrangement on the wafer 120 in a single printing process using a single reticle and without a reticle exchange operation.

Next, an example of a desirable embodiment of a lithography reticle according to the present invention will be described.

In FIG. 2, the reticle 201 is the main pattern area 2.
03 and the other surrounding areas. In this example, an alignment target pattern 207 for pre-alignment, a reticle cover 212, and a scribe 214 are formed as index patterns in the outer region. 2
16 is an empty area in which nothing is formed in the surrounding area. The reticle cover 212 is a pattern for preventing exposure light from affecting an adjacent frame during exposure of one frame on a wafer. The scribe 214 is also called a dicing line, and is a pattern that defines cutting lines (or cutting margins) for cutting out each frame as a chip from the wafer after the lithography process.

The reticle 201 is made of a material such as quartz that is normally used for reticles, and on its surface, a main pattern, an index pattern, and various other necessary patterns as described above are formed as a Cr vapor deposition film or the like.

[Effects of the Invention] The lithography reticle of the present invention and the reticle pattern transfer method using this reticle can simultaneously print a main pattern and an index pattern on a single reticle and in a single printing process, so that reticle production is easy. The effect is that the cost can be reduced to about 172 or less compared to the conventional method and productivity can be increased by up to 30%.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing an example of the reticle of the present invention, and FIGS. 1(b) to (e) show the reticle pattern transfer method of the present invention using the reticle of FIG. 1(a). FIG. 2 is a plan view showing an example of a desirable embodiment of the reticle shown in FIG. 1(a); FIG. The plan view shown and FIGS. 3(C) and (d) are similar to FIGS. 3(a) and (b).
FIG. 3 is a plan view for explaining an example of a process of a conventional reticle pattern transfer method using a reticle of FIG. 101.201,301,311...Reticle, 10
3.203, 303.313...Main pattern area, 1
05.305,315...Outer area (area other than the main pattern area), 207...Indicator pattern, 120.320...Wafer.

Claims (1)

[Claims] 1. In a reticle for lithography of a semiconductor device,
A lithography reticle characterized in that an index pattern is formed in an area other than the main pattern area. 2. A reticle pattern transfer method comprising the step of simultaneously printing a main pattern and an index pattern using the reticle according to claim 1.