Photomask structure

Abstract

A photomask structure includes a layout pattern and at least one auxiliary pattern. The layout pattern includes multiple corners. The auxiliary pattern covers at least one corner. A gap exists between the edge of the layout pattern and the auxiliary pattern.

Description

Technical Field

[0001] The present invention relates to a mask structure, and in particular to a mask structure including an auxiliary pattern. Prior Art

[0002] Lithography plays a crucial role in semiconductor manufacturing. However, the photoresist patterns formed by lithography often exhibit corner rounding defects. Therefore, developing masks that can reduce corner rounding is an ongoing effort. Summary of the Invention

[0003] The present invention provides a photomask structure which can effectively reduce the corner rounding of a photoresist pattern formed by a lithography process.

[0004] The present invention provides a mask structure comprising a layout pattern and at least one assist pattern. The layout pattern includes a plurality of corners. The assist pattern covers at least one corner. A gap is provided between an edge of the layout pattern and the assist pattern.

[0005] According to an embodiment of the present invention, in the above-mentioned mask structure, the distance between the edge of the layout pattern and the auxiliary pattern can be the minimum distance specified by the design rule.

[0006] According to an embodiment of the present invention, in the above-mentioned mask structure, the edge of the layout pattern and the auxiliary pattern do not contact each other.

[0007] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may be located outside the layout pattern.

[0008] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may be located inside the layout pattern.

[0009] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern can cover at least two corners.

[0010] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may have an L-shape.

[0011] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may include a U-shape.

[0012] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may be a serif.

[0013] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern may be a hammerhead.

[0014] According to an embodiment of the present invention, in the above-mentioned mask structure, the layout pattern can be a light-proof pattern or a phase-shift pattern.

[0015] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern located outside the layout pattern can be a light-proof pattern or a phase-shift pattern.

[0016] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern located inside the layout pattern can be a light-transmitting pattern.

[0017] According to an embodiment of the present invention, in the above-mentioned mask structure, the layout pattern may be a light-transmitting pattern.

[0018] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern located outside the layout pattern can be a light-transmitting pattern.

[0019] According to an embodiment of the present invention, in the above-mentioned mask structure, the auxiliary pattern located inside the layout pattern can be an opaque pattern or a phase-shift pattern.

[0020] Based on the above, the present invention proposes a photomask structure comprising a layout pattern and at least one auxiliary pattern. The auxiliary pattern covers at least one corner of the layout pattern, and a gap is provided between the edge of the layout pattern and the auxiliary pattern. Therefore, when using this photomask structure for lithography, the pattern fidelity of the lithography process can be improved. Thus, when using this photomask structure for lithography, the corner rounding of the photoresist pattern formed by the lithography process can be effectively reduced, thereby improving the process window of the semiconductor process.

[0021] To make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings. Simple diagram description

[0022] FIG. 1 is a schematic diagram of a mask structure according to some embodiments of the present invention. Implementation Method

[0023] The following examples are listed and illustrated in detail, but the examples provided are not intended to limit the scope of the present invention. For ease of understanding, identical components will be designated by the same reference numerals throughout the following description. Furthermore, the drawings are for illustrative purposes only and are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or decreased for clarity.

[0024] FIG. 1 is a schematic diagram of a mask structure according to some embodiments of the present invention.

[0025] 1 , a mask structure 10 includes a layout pattern 100 and at least one assist pattern 200. In some embodiments, the mask structure 10 may be a binary mask or a phase shift mask (PSM), but the present invention is not limited thereto.

[0026] The layout pattern 100 includes a plurality of corners C. The layout pattern 100 may be a main pattern on the mask structure 10. In addition, the shape of the layout pattern 100 may be determined according to product design and is not limited to the shape shown in FIG. 1 .

[0027] In this embodiment, the number of auxiliary patterns 200 is shown as multiple, but the present invention is not limited thereto. As long as the mask structure 10 includes at least one auxiliary pattern 200, it falls within the scope of the present invention. The auxiliary pattern 200 can be used to improve the pattern fidelity of the lithography process. In some embodiments, when the mask structure 10 includes multiple auxiliary patterns 200, the auxiliary patterns 200 can be separated from each other. For example, the auxiliary pattern 200A, the auxiliary pattern 200B, the auxiliary pattern 200C, and the auxiliary pattern 200D can be separated from each other.

[0028] The auxiliary pattern 200 covers at least one corner C. In some embodiments, the auxiliary pattern 200 may cover at least two corners C. For example, the auxiliary pattern 200A may cover one corner C, the auxiliary pattern 200B may cover one corner C, the auxiliary pattern 200C may cover two corners C, and the auxiliary pattern 200D may cover two corners C. As long as the auxiliary pattern 200 covers at least one corner C, it falls within the scope of the present invention.

[0029] A gap G is provided between the edge of the layout pattern 100 and the auxiliary pattern 200, thereby improving the pattern fidelity of the lithography process and effectively reducing corner rounding of the photoresist pattern formed by the lithography process. The spacing S between the edge of the layout pattern 100 and the auxiliary pattern 200 can be the minimum spacing specified by the design rules. In some embodiments, the edge of the layout pattern 100 and the auxiliary pattern 200 do not contact each other.

[0030] In some embodiments, the auxiliary pattern 200 may be located outside the layout pattern 100. For example, the auxiliary pattern 200A, the auxiliary pattern 200C, and the auxiliary pattern 200D may be located outside the layout pattern 100. In some embodiments, the auxiliary pattern 200 may be located inside the layout pattern 100. For example, the auxiliary pattern 200B may be located inside the layout pattern 100.

[0031] In some embodiments, the auxiliary pattern 200 may be L-shaped. For example, the auxiliary pattern 200A and the auxiliary pattern 200B may be L-shaped. In some embodiments, the auxiliary pattern 200 may be U-shaped. For example, the auxiliary pattern 200C and the auxiliary pattern 200D may be U-shaped.

[0032] In some embodiments, the auxiliary pattern 200 may be a serif or a hammerhead. For example, the auxiliary pattern 200A and the auxiliary pattern 200B may be a serif, and the auxiliary pattern 200C and the auxiliary pattern 200D may be a hammerhead.

[0033] In some embodiments, the layout pattern 100 may be a light-opaque pattern or a phase-shift pattern, the auxiliary pattern 200 located outside the layout pattern 100 may be a light-opaque pattern or a phase-shift pattern, and the auxiliary pattern 200 located inside the layout pattern 100 may be a light-transmitting pattern. For example, if the mask structure 10 is a binary mask, the layout pattern 100 may be a light-opaque pattern, the auxiliary pattern 200 located outside the layout pattern 100 may be a light-opaque pattern, and the auxiliary pattern 200 located inside the layout pattern 100 may be a light-transmitting pattern. Furthermore, if the mask structure 10 is a phase-shift mask, the layout pattern 100 may be a phase-shift pattern, the auxiliary pattern 200 located outside the layout pattern 100 may be a phase-shift pattern, and the auxiliary pattern 200 located inside the layout pattern 100 may be a light-transmitting pattern.

[0034] In some embodiments, the layout pattern 100 may be a light-transmitting pattern, the auxiliary patterns 200 located outside the layout pattern 100 may be light-transmitting patterns, and the auxiliary patterns 200 located inside the layout pattern 100 may be opaque patterns or phase-shift patterns. For example, if the mask structure 10 is a binary mask, the layout pattern 100 may be a light-transmitting pattern, the auxiliary patterns 200 located outside the layout pattern 100 may be light-transmitting patterns, and the auxiliary patterns 200 located inside the layout pattern 100 may be opaque patterns. Furthermore, if the mask structure 10 is a phase-shift mask, the layout pattern 100 may be a light-transmitting pattern, the auxiliary patterns 200 located outside the layout pattern 100 may be light-transmitting patterns, and the auxiliary patterns 200 located inside the layout pattern 100 may be phase-shift patterns.

[0035] In some embodiments, the light transmittance of the opaque pattern may be 0%. In some embodiments, the light transmittance of the phase-shift pattern may be 3% to 15%. In some embodiments, the light transmittance of the light-transmitting pattern may be 100%. In some embodiments, the phase difference between light passing through the phase-shift pattern and light passing through the light-transmitting pattern may be 180 degrees.

[0036] In some embodiments, the mask structure 10 may further include a transparent substrate (not shown), and the layout pattern 100 and the auxiliary pattern 200 may be located on the transparent substrate. The transparent substrate of the mask structure 10 is well known to those skilled in the art, and its description is omitted here.

[0037] Based on the above embodiment, it can be seen that the mask structure 10 includes a layout pattern 100 and at least one auxiliary pattern 200. The auxiliary pattern 200 covers at least one corner C of the layout pattern 100, and a gap G is formed between the edge of the layout pattern 100 and the auxiliary pattern 200. Therefore, when the mask structure 10 is used in a lithography process, the pattern fidelity of the lithography process can be improved. As a result, when the mask structure 10 is used in a lithography process, the corner rounding of the photoresist pattern formed by the lithography process can be effectively reduced, and the process margin of the semiconductor process can be improved.

[0038] In summary, in the mask structure of the above embodiment, the auxiliary pattern covers at least one corner of the layout pattern, and a gap is provided between the edge of the layout pattern and the auxiliary pattern, thereby improving the pattern fidelity of the lithography process. Thus, when the mask structure of the above embodiment is used for lithography, the rounding of the corners of the photoresist pattern formed by the lithography process can be effectively reduced, and the process margin of the semiconductor process can be improved.

[0039] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary skill in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

[0040] 10: Mask structure 100: Layout pattern 200, 200A, 200B, 200C, 200D: Auxiliary pattern C: Corner G: Gap S: Spacing

Claims

1. A photomask structure, comprising: The layout pattern includes multiple corners; And at least one auxiliary pattern, wherein the auxiliary pattern covers at least one of the corners, there is a gap between the edge of the layout pattern and the auxiliary pattern, and the auxiliary pattern does not cover the entire layout pattern.

2. The photomask structure as described in claim 1, wherein the spacing between the edge of the layout pattern and the auxiliary pattern is the minimum spacing specified by the design rules.

3. The photomask structure as described in claim 1, wherein the edges of the layout pattern do not contact the auxiliary pattern.

4. The photomask structure as claimed in claim 1, wherein the auxiliary pattern is located outside the layout pattern.

5. The photomask structure as claimed in claim 1, wherein the auxiliary pattern is located inside the layout pattern.

6. The photomask structure as claimed in claim 1, wherein the auxiliary pattern covers at least two of the corners.

7. The photomask structure as claimed in claim 1, wherein the shape of the auxiliary pattern includes an L-shape.

8. The photomask structure as claimed in claim 1, wherein the shape of the auxiliary pattern includes a U-shape.

9. The photomask structure as claimed in claim 1, wherein the auxiliary pattern includes serifs.

10. The photomask structure as claimed in claim 1, wherein the auxiliary pattern includes a hammerhead.

11. The photomask structure as claimed in claim 1, wherein the layout pattern includes an opaque pattern or a phase-shifting pattern.

12. The photomask structure as claimed in claim 11, wherein the auxiliary pattern located outside the layout pattern comprises an opaque pattern or a phase-shifting pattern.

13. The photomask structure as claimed in claim 11, wherein the auxiliary pattern located inside the layout pattern includes a light-transmitting pattern.

14. The photomask structure as claimed in claim 1, wherein the layout pattern includes a light-transmitting pattern.

15. The photomask structure as claimed in claim 14, wherein the auxiliary pattern located outside the layout pattern includes a light-transmitting pattern.

16. The photomask structure as claimed in claim 14, wherein the auxiliary pattern located inside the layout pattern comprises an opaque pattern or a phase-shifting pattern.

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