CN101373326A - Photomask layout - Google Patents

Abstract

The invention discloses a photomask layout pattern. The photomask layout pattern comprises an H-shaped pattern which comprises a first linear pattern, a second linear pattern and a middle area for connecting the first linear pattern and the second linear pattern, wherein the first linear pattern and the second linear pattern are parallel to each other, and a plurality of dense lines and interval patterns similar to zebra stripes are arranged in the middle area. The distance between the dense lines and the interval patterns is small enough to exceed the resolution capability of an exposure machine table, so that the light energy penetrating through the middle area is not enough to expose the dense lines and the interval patterns in the photoresist.

Description

Photomask layout diagram

technical field

The present invention relates to the field of semiconductor technology, in particular to an improved photomask layout, which is suitable for H-shaped pattern transfer without optical proximity correction (OPC).

Background technique

In the semiconductor process, in order to smoothly transfer the pattern of integrated circuits (integrated circuits) to the semiconductor chip, the circuit pattern must be designed on the photomask layout first, and then the photomask output according to the photomask layout A photomask pattern is used to make a photomask, and the pattern on the photomask is transferred to the semiconductor chip in a certain proportion.

Since the critical dimension (CD) of the pattern that can be produced on the photomask will be limited by the resolution limit (resolution limit) of the optical exposure tool (optical exposure tool), when the integration (integration) gradually Improvement, the circuit pattern design is getting smaller and smaller, when the exposure process is performed on these high-density arrayed photomask patterns for pattern transfer, it is easy to produce optical proximity effect (optical proximity effect, OPE), resulting in deviation of pattern transfer ( deviation). For example, right-angled corner rounded (right-angled corner rounded), line end shortened (line end shortened), and line width increase or decrease (line width increase/decrease), etc., are common optical proximity effects caused by photomasks. Die pattern defects.

In order to avoid the distortion of the photomask pattern transfer caused by the above-mentioned optical proximity effect, optical proximity correction (optical proximity correction, OPC) is usually performed on the photomask layout to eliminate the optical proximity effect when making the photomask. The method is to use computer aided design (computer aided design, CAD) to calculate and correct the original photomask pattern to be exposed on the semiconductor substrate, and calculate and correct it with a data computer and software package to obtain a photomask pattern different from the original photomask pattern. The photomask pattern is corrected, and then the corrected photomask pattern is input into a computer for archiving, and the corrected pattern is made on the photomask.

Please refer to Fig. 1 and Fig. 2, wherein Fig. 1 illustrates an H-type layout pattern, and Fig. 2 depicts the after-developed (after-developed) after the H-type layout pattern of Fig. 1 is transferred to the photoresist by a photolithography process. -inspect, ADI) layout results. As shown in Figure 1, in the originally designed H-shaped layout pattern 1 (the shaded part is the opaque chromium pattern, and the blank area is the light-transmitting pattern), no OPC auxiliary pattern was added, but after the photolithography process transfer After reaching the photoresist, it will be found that the spacer region 2 is shortened and receded. Compared with the ideal position indicated by the dotted line, the offset value can reach about 50nm on each side. Another defect occurs in the linear interval region 3 adjacent to the H-shaped layout pattern 1 , which will be affected at the same time to reduce the line width.

In the past, such defects were mainly made by using the OPC method, as shown in Figure 3, adding a hammer head auxiliary pattern 4 to the H-shaped layout pattern. However, simply adding the head-hammer auxiliary pattern 4 still cannot solve the problem of tapered profile of the adjacent straight-line interval region 3 . In addition, in the past, the OPC method was used to form the modified photomask, and the steps were not only much complicated, but also the cost was relatively increased.

Contents of the invention

Therefore, the main purpose of the present invention is to provide an improved photomask layout to solve the above-mentioned problems in the prior art.

To achieve the above object, the present invention provides a photomask layout pattern, including an H-shaped pattern, which includes a first straight line pattern, a second straight line pattern, and an intermediate line connecting the first straight line pattern and the second straight line pattern. area, wherein the first straight line pattern and the second straight line pattern are parallel to each other, and a plurality of zebra-crossing-like dense lines and interval patterns are arranged in the middle area. The pitch of the dense lines and space patterns must be small enough to exceed the resolution capability of the exposure machine, so that the light energy penetrating the middle area is not enough to expose the dense lines and space patterns in the photoresist.

In order to make the above-mentioned purpose, features, and advantages of the present invention more comprehensible, the preferred implementation modes are exemplified below and described in detail in conjunction with the accompanying drawings. However, the following preferred embodiments and drawings are for reference and illustration only, and are not intended to limit the present invention.

Description of drawings

FIG. 1 shows an H-shaped layout pattern.

FIG. 2 shows the layout result after development after the H-shaped layout pattern in FIG. 1 is transferred onto the photoresist through a photolithography process.

FIG. 3 shows the modified layout pattern after adding the head hammer auxiliary pattern to the H-shaped layout pattern.

FIG. 4 shows an improved photomask layout according to a preferred embodiment of the present invention.

FIG. 5 shows the post-development result after the photomask layout in FIG. 4 is transferred to the photoresist.

Explanation of reference signs

1 H-shaped layout pattern 2 Interval area

3 Straight line interval area 4 Head hammer auxiliary pattern

10 H-shaped pattern 10a The first straight line pattern

10b Second line pattern 10c Intermediate area

12 Separation area 14a Separation area

14b Interval area 20a Third line pattern

20b Fourth line pattern 100 photomask layout

102 Dense Lines 104 Spacing Patterns

Detailed ways

Please refer to FIG. 4 , which shows an improved photomask layout according to a preferred embodiment of the present invention, wherein the opaque patterns are also represented by shaded areas, for example, chrome patterns, and blanks are represented by blanks. Regions to represent light-transmitting patterns.

The main purpose of the present invention is to accurately transfer the photomask layout 100 as depicted in FIG. , and the problem of reducing the width of the adjacent linear spaces 14a and 14b on both sides of the H-shaped pattern can also be solved.

As shown in FIG. 4, the photomask layout 100 includes an H-shaped pattern 10, which includes a first straight pattern 10a, a second straight pattern 10b, and an intermediate region 10c connecting the first straight pattern 10a and the second straight pattern 10b. . Wherein, the first straight line pattern 10 a and the second straight line pattern 10 b are parallel to each other and arranged along the reference axis Y in the figure.

According to a preferred embodiment of the present invention, the line width L ₁ of the first line pattern 10a is the same as the line width L ₂ of the second line pattern 10b, for example, the line width L _{1 of the first line pattern 10a is the same as the line width L 2} of the second line pattern 10b. The line widths L ₂ of the two straight line patterns 10 b are both 0.11 μm (L ₁ =L ₂ =0.11 μm).

According to a preferred embodiment of the present invention, the line width L ₁ of the first line pattern 10a, the line width L ₂ of the second line pattern 10b, and the space width S between the first line pattern 10a and the second line pattern 10b The three are the same, for example, the line width L ₁ of the first line pattern 10a, the line width L ₂ and the space width S of the second line pattern 10b are all 0.11 μm (L ₁ =L ₂ =S=0.11 μm).

According to a preferred embodiment of the present invention, the length of the middle region 10c along the reference axis Y is about 0.37 microns. The present invention is characterized in that a plurality of dense lines 102 and space 104 patterns arranged along the reference axis X-axis are arranged in the middle region 10c, similar to a zebra-crossing pattern, and is characterized in that the distance between the dense lines 102 and the space 104 patterns The (pitch) must be small enough to exceed the resolution capability of the exposure machine, so that the light energy penetrating the middle region 10c is not enough to expose the dense lines 102 and space patterns 104 in the photoresist.

For example, with the current 193nm exposure machine, without using off-axis illumination (off-axis illumination) and other resolution enhancement techniques, the distance between the dense lines 102 and the spaces 104 patterns can be less than 130nm, and the lines 102 The ratio of the line width to the width of the space pattern 104 may be, for example, 65/65 or 90/40, but is not limited thereto.

In addition, according to a preferred embodiment of the present invention, a third straight pattern 20a is provided on the other side of the first straight pattern 10a relative to the middle region 10c, and the third straight pattern 20a is separated from the first straight pattern 10a. Between them is the spacer area 14a. On the other side of the second straight line pattern 10b opposite to the middle area 10c, there is a fourth straight line pattern 20b, and a space area 14b is formed between the fourth straight line pattern 20b and the second straight line pattern 10b.

Wherein, according to a preferred embodiment of the present invention, the first straight line pattern 10a, the second straight line pattern 10b, the third straight line pattern 20a and the fourth straight line pattern 20b that are parallel to each other have the same line width, for example, 0.11 Microns.

According to a preferred embodiment of the present invention, the line width and space width S of the first straight line pattern 10a, the second straight line pattern 10b, the third straight line pattern 20a and the fourth straight line pattern 20b, the width of the space area 14a and the space area 14b are all the same, for example, both are 0.11 microns.

FIG. 5 illustrates an after-development (ADI) layout result after the photomask layout 100 in FIG. 4 is transferred onto a photoresist. The results show that the receding length of each side of the spacing region 12 can be controlled below about 10 nm, and the width reduction problem of the adjacent straight spacing regions on both sides of the H-shaped pattern is also improved.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims (8)

1. photomask layout pattern, include H type pattern, it comprises first straight-line pattern, second straight-line pattern and the zone line that connects this first straight-line pattern and this second straight-line pattern, wherein this first straight-line pattern and this second straight-line pattern are parallel to each other, are provided with many intensive lines and intermittent pattern in this zone line.

2. photomask layout pattern as claimed in claim 1, wherein the spacing of these intensive lines and intermittent pattern is little of the analytic ability that can surpass exposure bench, makes the light ray energy that penetrates this zone line be not enough to allow these intensive lines and intermittent pattern be exposed in photoresist.

3. photomask layout pattern as claimed in claim 1, wherein the spacing of these intensive lines and intermittent pattern is less than 130nm.

4. photomask layout pattern as claimed in claim 1, wherein this first straight-line pattern, this second straight-line pattern and this intensive lines are light tight zone.

5. photomask layout pattern as claimed in claim 1, wherein this intermittent pattern is a transmission region.

6. photomask layout pattern as claimed in claim 1, wherein these intensive lines and this first straight-line pattern and this second straight-line pattern are quadrature.

7. photomask layout pattern as claimed in claim 1, wherein this first straight-line pattern is identical with the live width of this second straight-line pattern.

8. photomask layout pattern as claimed in claim 7, wherein the live width of this first straight-line pattern and this second straight-line pattern is 0.11 micron.

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