KR20080099911A

KR20080099911A - Metod for fabricating in photo mask

Info

Publication number: KR20080099911A
Application number: KR1020070045791A
Authority: KR
Inventors: 김문식
Original assignee: 주식회사 하이닉스반도체
Priority date: 2007-05-11
Filing date: 2007-05-11
Publication date: 2008-11-14

Abstract

After forming the transmittance reducing film on the transparent substrate, forming the target film pattern on the transmittance reducing film, and then detect a region having a relatively large gap between the target film patterns, and the area of the relatively large gap between the target film pattern A method of manufacturing a photomask for patterning the transmittance reducing film so that the transmittance reducing film remains.

Description

Method for manufacturing photomask {Metod for fabricating in photo mask}

1 is a cross-sectional view illustrating a problem according to a conventional method for manufacturing a photomask.

2 to 8 are cross-sectional views illustrating a method of manufacturing a photomask according to the present invention.

9 is a cross-sectional view illustrating a method of forming a pattern using a photomask manufactured according to the present invention.

The present invention relates to a method of manufacturing a photomask, and more particularly, to a method of manufacturing a photomask having a light transmittance reducing film.

Photolithography (photolithograpgy) process is used as a method for implementing a pattern to be formed on a semiconductor device. Before performing the photolithography process, a process of manufacturing a photomask on which circuits and design patterns for implementing a semiconductor device are drawn is first performed. For example, in the process of fabricating a binary photomask, a light blocking film and a resist film are formed on a transparent substrate, and then a resist pattern identical to a circuit pattern to be implemented is formed by performing exposure and development processes. After etching the light blocking film using the resist pattern as an etching mask, the resist pattern is removed.

However, as semiconductor devices are highly integrated, the pattern critical width (CD) and pattern uniformity implemented on the photomask are becoming more important. Accordingly, after the photomask is manufactured, the linewidth of the pattern is measured using a linewidth measuring instrument.

However, in the process of fabricating the photomask, a defective pattern having a line width relatively smaller than the line width of the normal pattern may be caused by various process abnormalities.

Referring to FIG. 1, a phase inversion film 110 pattern and a light blocking film 120 pattern are formed on a mask substrate 100. However, when the phase inversion film 110 pattern and the light blocking film 120 pattern are formed, a defective pattern 130 having a line width smaller than a desired threshold line width may be formed by an exposure apparatus or the like. In the case of the defective pattern 130 having a small line width, it is difficult to correct the line width once implemented. Therefore, when the defective pattern 130 having a small line width is found through the measuring device, the photomask is discarded and the exposure conditions are adjusted to manufacture the photomask again.

However, this method does not know how much the line width and pattern uniformity of the pattern will be improved even if the exposure conditions are adjusted. Since the photomask has to be fabricated from the beginning, the manufacturing period may be lengthened and the manufacturing cost may be increased, resulting in lowered device yield. Can be.

An object of the present invention is to provide a method of manufacturing a photomask that can improve the uniformity of the pattern line width implemented on the wafer.

In order to achieve the above technical problem, according to the photomask manufacturing method according to the present invention, forming a transmittance reduction film on a transparent substrate; Forming a target film pattern on the transmittance reducing film; Detecting an area having a relatively large gap between the target layer patterns; And patterning the transmittance reducing film so that the transmittance reducing film remains in a region where the distance between the target film patterns is relatively large.

The transmittance reducing film is preferably formed of a silicon oxynitride film.

The mask pattern is preferably formed of a light blocking film pattern.

The mask pattern may be formed of a phase inversion film pattern and a light blocking film pattern.

According to the present invention, the transmittance reduction film is etched in the region between the normally patterned patterns, and the transmittance reduction film is formed in the region where the interval between the patterns is relatively large due to poor patterning. It is possible to improve the uniformity of the pattern line width implemented. Accordingly, even if a defect in the pattern line width occurs in the photomask manufacturing process, the photomask does not have to be remanufactured, so that the yield of the device may be improved.

Referring to FIG. 2, a transmittance reduction film 210, a phase inversion film 220, and a light blocking film 230 are formed on a transparent substrate 200 such as quartz. The transmittance reduction film 210 may be formed of silicon oxynitride (SiON). The phase inversion film 221 may be formed of a material capable of inverting the phase of transmitted light, for example, molybdenum silicon nitride (MoSiN). The light blocking layer 222 may be formed of a material capable of blocking transmitted light, such as a chromium (Cr) film. In the embodiment of the present invention, a phase inversion mask is described as an example, but may be applied to other types of photomasks, such as a binary mask.

A first resist pattern 240 is formed on the light blocking film 230 to selectively expose the light blocking film. Specifically, after applying a resist film (not shown) on the light blocking film 230, a circuit pattern to be implemented on the wafer is transferred to the resist film using an electron beam. The resist film to which the circuit pattern is transferred is developed to form the first resist pattern 240.

Referring to FIG. 3, the light blocking film and the phase inversion film exposed by the first resist pattern 240 (in FIG. 1) are selectively etched to form the light blocking film 230 pattern and the phase inversion film 220 pattern. Then, the transmittance reducing film 210 is selectively exposed between the light blocking film 230 pattern and the phase inversion film 220 pattern.

However, in the process of forming the pattern, a difference in the pattern line width may occur due to various process abnormalities. In particular, when the defective pattern 250 having a line width smaller than the normal pattern is implemented on the photomask, it is difficult to correct it. Therefore, the photomask must be discarded and the photomask must be manufactured again.

Referring to FIG. 4, a spacing between the light blocking film 230 pattern and the phase reversing film 220 pattern is measured to have a region having a line width relatively wider than that between the normal pattern and the normal pattern (see a). (see b).

If a bad pattern having a line width smaller than a desired threshold is implemented on the photomask, a difference in pattern size causes a spacing difference between the pattern and the pattern. That is, the region between the defective pattern and the normal pattern having a smaller line width than the region between the normal pattern and the normal pattern is represented by a relatively wide spacing. Since the pattern and the area between the patterns are areas through which light is transmitted, the larger the interval, the greater the amount of light transmitted. Thus, a defective pattern having a small line width is formed on the wafer.

Accordingly, in the embodiment of the present invention, even if a bad pattern having a small line width is implemented on the photomask, the uniformity of the pattern line width implemented on the wafer may be improved by performing the following process.

Referring to FIG. 5, a second resist pattern 260 is formed on the transparent substrate on which the light blocking film 230 pattern and the phase inversion film 220 pattern are formed to expose a region (see b) between the normal pattern and the normal pattern. do.

Referring to FIG. 6, the transmittance reduction film 210 exposed by the second resist pattern 260 is selectively etched. That is, the transmittance reduction film 210 is removed from the transparent substrate 200 between the normal patterns, and the transmittance reduction film 210 is formed on the transparent substrate having a large gap between the patterns due to the defective pattern.

Therefore, the light transmitted during the subsequent exposure passes as it is between the normal pattern from which the transmittance reduction film 210 is removed, and transmits by causing a decrease in transmittance between the defective pattern and the normal pattern on which the transmittance reduction film 210 is formed. The amount of light will be reduced.

Referring to FIG. 7, a third resist pattern 270 exposing a portion of the light blocking film 230 pattern and the phase inversion film 220 pattern is disposed on the transparent substrate 200 on which the transmittance reduction film 210 is selectively removed. Form.

Referring to FIG. 8, after selectively removing the light blocking film pattern exposed by the third resist pattern 270 of FIG. 7, the third resist pattern is removed. Then, a phase inversion film 220 pattern and a light blocking film 230 pattern are formed on a portion of the mask substrate 200, and a phase inversion film 220 pattern is formed on a portion of the mask substrate 200.

Accordingly, even in the photomask having the defective pattern, the line width of the pattern formed on the wafer may be adjusted due to the difference in the amount of light transmitted through the region where the transmittance reduction film is not formed and the region where the transmittance reduction film is formed.

Referring to FIG. 4, when the exposure process is performed using a photomask (see FIG. 8) in which the transmittance reduction film is selectively formed, light transmitted through the region between the normal pattern and the normal pattern is transparent substrate 200. The light is transferred to the resist 320 formed on the wafer 300 on which the etch target layer 310 pattern is formed, and the light transmitted through the region between the normal pattern and the defective pattern decreases the amount of light while passing through the transmittance reduction film. Is transferred to 210).

That is, the light transmitted through the region between the normal pattern and the normal pattern is transferred to the resist 210 formed on the wafer 200 with the same spacing, and transmitted through the region between the defective pattern and the normal pattern. Light is transferred to the resist with a smaller amount of light and with a narrower gap.

Accordingly, the resist pattern 320 having the same line width as the pattern formed on the photomask is formed, and the uniformity of the resist pattern 320 implemented on the wafer can be improved.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications are possible by those skilled in the art within the technical spirit of the present invention. Of course.

As described so far, according to the method of manufacturing a photomask according to the present invention, a pattern line width implemented on a wafer can be adjusted using a light transmittance reducing film without modifying the pattern of the photomask. Accordingly, it is possible to improve the uniformity of the pattern line width implemented on the wafer.

In addition, even if a bad pattern is generated on the photomask, the photomask does not need to be manufactured again, thereby reducing the process cost and the process time, thereby improving the yield of the device.

Claims

Forming a transmittance reduction film on the transparent substrate;

Forming a target layer pattern on the transmittance reduction layer;

Detecting an area having a relatively large gap between the target layer patterns; And

And patterning the transmittance reducing film so that the transmittance reducing film remains in a region where the interval between the target film patterns is relatively large.

The method of claim 1,

The transmittance reduction film is a method of manufacturing a photomask formed of a silicon oxynitride film.

The method of claim 1,

The mask pattern is a photomask manufacturing method of forming a photomask pattern.

The method of claim 1,

The mask pattern is a photomask manufacturing method of forming a phase inversion film pattern and the light blocking film pattern.