KR20060000724A - Lithography mask - Google Patents

Abstract

The present invention relates to an exposure mask, and the present invention relates to an exposure mask in which a pattern including a transmissive slit capable of inducing light diffraction in a light shielding pattern for exposure is formed in order to efficiently form a curved pattern according to a circuit design. It is a mask.

Description

Exposure mask {LITHOGRAPHY MASK}

1 is an exposure mask to which the prior art OPC is applied.

2A and 2B are schematic views of exposure masks and thus patterns formed in a semiconductor substrate according to the present invention;

3 is a plan view of an exposure mask according to the present invention;

4 is a plan view of a pattern formed on a semiconductor substrate in a lithography process using an exposure mask according to the present invention.

5 is a cross-sectional view of an exposure mask according to the present invention.

<Description of Symbols for Major Parts of Drawings>

10, 100: exposure mask 20: line type light shielding pattern for OPC

30: curved shading pattern 110: rectangular shape shading pattern

120: first shading pattern 130: second shading pattern

140: third light shielding pattern 125: first light-emitting slit

145: second flood slit 150: MoSiON translucent half-tone

200: semiconductor substrate 210: curved pattern

220: asymmetrical bending pattern 230: symmetrical bending pattern

240: corner rounding pattern λ: wavelength of exposure light

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure mask, and more particularly, to a technique for forming a light shielding pattern and a light transmitting pattern on a quartz substrate of an exposure mask so as to be patterned well in order to efficiently form a curved pattern according to a circuit design.

In the patterning method using the exposure mask according to the prior art, the pattern is formed into a deformed shape which is unexpected when patterning a curved pattern by a line shape or a line crossing on a semiconductor. Accordingly, the left and right rectangular auxiliary light shielding patterns are attached to the original exposure pattern to produce an exposure mask, and patterning is performed on the semiconductor substrate using the exposure mask. The exposure mask pattern formed in this manner is called OPC (Optical Proximity Correction) and uses a proximity effect due to a difference in density from the surrounding pattern due to the adhesion of the pattern.

1 is an exposure mask to which the OPC according to the prior art is applied.

A line-shaped light blocking pattern 20 including a fine auxiliary pattern and a plurality of line-type light blocking patterns are formed on the quartz substrate 10, and a curved blocking pattern 30 having an intersecting shape is formed while the line-shaped light blocking patterns meet. It is.

At this time, the chromium oxide film and the E-beam photosensitive film layer are formed on the quartz substrate having good transparency, and the pattern is formed by exposing and developing the molecular beam of the E-beam photosensitive film by scanning and scanning the E-beam. Next, the chromium oxide film is etched by an etching process and an E-beam photosensitive film layer is removed to manufacture an exposure mask.

Here, the technique using the E-beam to form a fine auxiliary pattern for OPC is difficult. The limit of current resolution is about 0.2 占 퐉, and pattern production below it is difficult. In addition, in order to manufacture an exposure mask for forming a 0.1 μm-class DRAM chip on a semiconductor substrate, there is a problem that 20 hours or more of E-beam writing time is required. Particularly, in the case of a pattern of a shape as shown in FIG. 1 or a more complicated pattern having an E-beam device of a VSB (Variable Shape Beam) method using various types of beams, the data analysis time and the number of combinations increase exponentially. It takes a lot of time. In addition, there is a limit to implement the fine shape as it is, the shape of the circuit may be limited, and in the case of the bend pattern, there is a problem that the implementation of corner rounding is poor.

The present invention is to solve the above problems, the present invention is to include a light-transmitting slit to induce the diffraction of light in the light shielding pattern of the exposure mask, in order to efficiently form a curved pattern according to the circuit design, It is an object of the present invention to provide an exposure mask capable of forming a pattern freely without limitation to an E-beam apparatus for manufacturing an exposure mask and accurately patterning a complicated shape such as a curved shape on a semiconductor substrate.

The present invention is to achieve the above object, a first light shielding pattern or a second light shielding pattern provided with two line-shaped light shielding pattern is provided,

At least one first light-transmitting slit formed inside the line-shaped first light-shielding pattern at a predetermined angle with an extension direction of the first light-shielding pattern;

An exposure mask comprising at least one second light-transmitting slit provided at an inner corner inside the second light-shielding pattern intersection.

Hereinafter, an exposure mask according to the present invention will be described in detail with reference to the accompanying drawings.

2A and 2B are schematic views of an exposure mask according to the present invention and thus a pattern formed on a semiconductor substrate.

Referring to FIG. 2A, when the light shielding pattern 110 having a rectangular shape is formed on the exposure mask 100, light projections having a thin rectangular shape are formed at corner portions facing each other at right angles to the direction of the long side of the rectangle. Add a slit 115 further.

Referring to FIG. 2B, the light blocking slit 115 is not formed as the rectangular light shielding pattern 110, but a portion in which the light transmitting slit 115 is located is formed inwardly. At this time, more light enters through the light transmitting slit 115 in the exposure process, and a portion where the light transmitting slit 115 is located is etched by the diffraction phenomenon of the light. Accordingly, the curved slit 115 may be formed on the semiconductor substrate 200 by including the light transmitting slit 115 in the rectangular light shielding pattern 110.                     

3 is a plan view showing an exposure mask according to the present invention.

Referring to FIG. 3, in an exposure mask 100 including a quartz substrate and a plurality of line light blocking patterns, the line light blocking pattern is formed of a rectangular material formed at a predetermined angle with a direction in which the line light blocking pattern extends. The exposure mask 100 further includes a rectangular second light-emitting slit 145 at an inner corner of the intersection where the first light-emitting slit 125 and the line-shaped light-shielding pattern meet. In this case, the sizes of the first and second light-emitting slits 125 and 145 are formed to have a width of 0.5 to 10 times and a length of 5 to 20 times the light source wavelength λ used during exposure, respectively. In addition, the first light transmitting slit 125 is formed to be spaced inward by a length of 0.5 to 5 times the wavelength of the light source used in the exposure from the boundary of the light blocking pattern, and the second light transmitting slit 145 is an angle of 45 degrees with the light blocking pattern. It is preferable to form to have.

3, the first light blocking pattern 120 includes a first light transmitting slit 125 having a diagonal shape in a line light blocking pattern, and the second light blocking pattern 130 extends a line in the line light blocking pattern. And a first translucent slit 125 in a direction perpendicular to the direction. The third light blocking pattern 140 is a portion of the exposure mask 100 that is formed of a plurality of line light blocking patterns and further includes a second rectangular light transmitting slit 145 at an inner corner of an intersection where the line light blocking patterns meet.

4 is a plan view of a pattern formed on a semiconductor substrate in a lithography process using an exposure mask according to the present invention.

The asymmetrical bending pattern 220 is formed by the first light blocking pattern 120 of FIG. 3. The light was diffracted in the diagonal direction to form a wave pattern in the longitudinal direction and an asymmetrical bending pattern 220 in the left and right directions.

The left-right symmetrical bending pattern 230 is formed by the second light blocking pattern 130 of FIG. 3.

The corner rounding pattern 240 is formed by the third light blocking pattern 140. As light passes through the second transmissive slit 145, it may diffract in the direction in which the slits are listed to form an improved corner rounding pattern 240 over the prior art.

5 are cross-sectional views of an exposure mask according to the present invention.

The exposure mask 100 according to the present invention is a cross-sectional view taken along line AA ′ in FIG. 3 and includes patterns 120, 130, and 140 formed on a transparent quartz substrate using chromium, which is a light blocking material, according to a circuit design. . As the light source used during exposure passes with a constant wavelength λ, light diffraction occurs at a portion where the slit is located.

In addition, the exposure mask 100 may further include a MoSiON translucent half-tone layer between the quartz substrate and the light shielding pattern. In this case, the MoSiON translucent half-tone layer includes the same light transmitting slit as the first and second light transmitting slits 125 and 145 or is formed as a single layer.

As described above, the present invention is limited to the E-beam equipment for manufacturing the exposure mask by including a light-transmitting slit in the light shielding pattern without forming a fine auxiliary pattern for the OPC method of the curved pattern according to the circuit design of the exposure mask You may not receive it. In addition, various bending patterns can be freely produced, and the degree of implementation of the pattern formed on the semiconductor substrate can be increased, and the time for manufacturing the exposure mask for this can be shortened.

Claims (6)

A second light blocking pattern provided with a line-shaped first light shielding pattern or two line-type light shielding patterns intersecting with each other, At least one first light-transmitting slit formed inside the line-shaped first light-shielding pattern at a predetermined angle with an extension direction of the first light-shielding pattern; And at least one second transmissive slit provided at an inner corner inside the second shielding pattern intersection. The method of claim 1, The size of the first and second light-emitting slits are 0.5 to 10 times the width and 5 to 20 times the length of the light source wavelength used during exposure, respectively. The method of claim 1, And the first light transmitting slit is spaced inward by a length of 0.5 to 5 times the wavelength of the light source used in the exposure from the boundary of the light blocking pattern. The method of claim 1, And the second light-transmitting slit is provided to have an angle of 45 degrees with the intersecting line-shaped light blocking pattern. The method of claim 1, And the exposure mask further comprises a MoSiON translucent half-tone layer between the quartz substrate and the light shielding pattern. The method of claim 5, And wherein said MoSiON translucent half-tone layer comprises a transmissive slit identical to said first and second transmissive slit.

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