KR20090094681A - Method for repairing defect in photo mask - Google Patents

Abstract

A method for repairing defect in photo mask is provided to repair clear defects in a phase shifting mask production process and to improve the yield. The phase shift layer pattern(111) is formed on the transparent substrate(100). It inspects whether the clear defect is generated in the phase shift layer pattern or not. The first repairing pattern(141) is formed in order to coincide the edge of the normal pattern with the edge of the clean defect. The second repairing pattern(142) is formed in the inside of the first repairing pattern. The carbon compound is used as the first and the second repairing pattern.

Description

Method for repairing defect in photo mask

The present invention relates to a method for manufacturing a photomask, and more particularly to a method for correcting defects in a photomask.

In order to manufacture a semiconductor device, a semiconductor substrate is fabricated, an oxidation process, a heat treatment process, a diffusion process, a deposition process, an ion implantation process, an etching process, and a mask patterning process are complicated. The process of reducing the desired portion on the semiconductor substrate between the deposition and etching is a function of the lithography process. Recently, a method of exposing a mask using a phase shift mask using a phase shifter has been studied. The phase inversion mask inverts the phase of light on the mask to reduce the spatial frequency of the pattern or to use the interference effect of increasing the contrast of the edges. This technology can achieve high resolution and increase the depth of focus (DOF). In the phase inversion mask, a phase inversion region pattern is disposed in the phase inversion region, and the phase inversion region and the light blocking layer are formed in the light blocking region. In order to manufacture such a phase inversion mask, complex processes such as patterning of a resist film using an electron beam, etching of a light shielding film and a phase inversion film using a resist film pattern, and ashing of a resist film must be performed. In the process of fabricating the phase inversion mask, part of the phase inversion film is removed or a clear defect such as a pinhole occurs. In order to correct this problem, a carbon dioxide deposition method using a focused ion beam (FIB) is used to set a work area based on a surrounding normal pattern to perform a correction operation. However, after correcting the defect in this way, if the modified photomask is checked with a measuring instrument such as AIMS, the critical demension (CD) in the modified portion is smaller than the critical size of the normal pattern. Will appear. As a result, repeating defects occur on the semiconductor substrate, resulting in a cost increase due to the remanufacturing of the mask and delayed product development schedule.

The photomask defect correction method of the present invention comprises the steps of: forming a phase inversion film pattern on a transparent substrate; Checking whether white defects have occurred in the phase shift pattern; Forming a first correction pattern at an edge of the white defect; And forming a second correction pattern inside the first correction pattern.

Carbon compounds may be used in the first and second crystal patterns.

The first and second crystal patterns may be formed using a focused ion beam (FIB) or an electron beam (E-beam).

The second correction pattern may be formed as a plurality of dot patterns.

The spacing between the dot patterns and the size of the dot patterns may be determined in a range of 15% or less based on the line width of the normal pattern.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

The present invention can improve the quality of the mask by correcting the white defect generated in the process of manufacturing the phase inversion mask through a correction operation. In addition, by minimizing the critical size (CD) error during the exposure process it can contribute to the improved yield through the exposure effect.

1A through 5B are diagrams for explaining a method of correcting a photomask defect according to the present invention. FIGS. 1A, 2A, 3A, 4A, and 5A are three-dimensional views, and FIGS. 1B, 2B, 3B, 4B, and 5B are plan views. to be.

1A and 1B, a phase inversion film 110 and a light blocking film 115 are formed on the transparent substrate 100. Molybdenum silicon nitride (MoSiN) may be formed as the phase inversion film 110, and a chromium film Cr may be formed as the light blocking film 115. Next, after the photoresist film is coated on the light blocking film 115, the photoresist pattern 120 is formed through exposure and development.

2A and 2B, the photoresist pattern 120 is etched using an etch mask to etch the light blocking film 115 (FIG. 1A) and the phase inversion film 110 (FIG. 1A) to etch the light blocking film pattern 116 and the phase inversion film. The pattern 111 is formed.

Referring to FIGS. 3A and 3B, after removing the photoresist pattern (120 of FIG. 2), the light blocking film pattern (116 of FIG. 2A) of the phase inversion region is removed to expose the phase inversion film pattern 111. Then, the phase inversion film pattern 111 is formed in the light blocking area. Subsequently, the inspection equipment (not shown) is used to check whether the white defect 130 has occurred on the mask. Through the matching of the coordinate system between the inspection equipment and the correction equipment it is possible to check the white defect (130). The white defect 130 may not uniformly apply the photoresist on the entire surface of the light blocking layer during the photoresist pattern forming process. In this case, since the photoresist pattern is not properly applied to the portion to be applied, a part of the phase inversion pattern 111 may be etched by the etching solution in a subsequent process to cause white defects 130.

4A and 4B, a first correction operation is performed on a portion where white defects occur.

Specifically, for example, a carbon compound is deposited on the edge pattern 141 by using a focused ion beam (FIB) or an electron beam (E-beam) on both sides of a pattern boundary where white defects (130 of FIG. 3A) occur. do. In this case, the boundary of the edge pattern 141 deposited on the edge of the white defect 130 is made to coincide with the boundary of the normal pattern, as shown. The width of the edge pattern 141 deposited on the edge of the white defect 130 is dependent on the size of the normal pattern and the optimal size is determined through simulation. Simulations can predict the results for each variable in advance, saving time and money by reducing the split of the experiment. In addition, the simulation can provide a broad interpretation of the experimental results.

5A and 5B, after the first modification, for example, a carbon compound is deposited by a dot pattern 142 inside the edge pattern 141 formed at the edge of the white defect 130. . The correction pattern 140 is formed of the etch pattern 141 and the dot pattern 142 of the carbon compound. In this case, the spacing and size between the dot patterns 142 may vary depending on the size of the white defects, and the error of the threshold size CD may be reduced by determining the range of 15% or less based on the line width of the normal pattern. The dot pattern 142 is to enable the control of the threshold size (CD) error by causing the transmittance and phase difference of light in the white defect correction region due to the interference between the dot patterns, wherein the size and number of the dot patterns are, for example, The optimal conditions can be determined through repeated simulations using simulation devices such as AIMS (aerial image system) equipment. AIMS takes less time and can accurately identify and verify the depth of etching using thin film density graphs.

The present invention can reduce the defects on the semiconductor substrate in accordance with the threshold size of the normal pattern by performing a clear defect (break) correction operation in the manufacturing process of the phase inversion mask. In addition, it may contribute to yield improvement by improving exposure effects.

1A through 5B are diagrams for explaining a method of correcting a photomask defect according to the present invention. FIGS. 1A, 2A, 3A, 4A, and 5A are three-dimensional views, and FIGS. 1B, 2B, 3B, 4B, and 5B are plan views. to be.

Claims (5)

Forming a phase inversion film pattern on the transparent substrate; Checking whether white defects have occurred in the phase shift pattern; Forming a first correction pattern at an edge of the white defect to coincide with an edge of a normal pattern; And And forming a second correction pattern inside the first correction pattern. The method of claim 1, A method for correcting defects in photomasks using carbon compounds in the first and second correction patterns. The method of claim 1, The first and second correction patterns are formed using a focused ion beam (FIB) or an electron beam (E-beam). The method of claim 1, The method of correcting a defect of a photomask in which the second correction pattern is formed into a plurality of dot patterns. The method of claim 4, wherein The gap between the dot patterns and the size of the dot pattern is determined in the range of 15% or less based on the line width of the normal pattern.

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