Pattern for optical proximity correction and design method of photomask pattern

Abstract

The invention discloses a design method of a pattern for optical proximity correction and a photomask pattern. The pattern for optical proximity correction includes a main body portion and a T-shaped portion. The main body part is provided with at least one right-angle corner, wherein the right-angle corner is composed of a first side edge and a second side edge. The T-shaped part comprises a head part and an extension part, and the extension part is connected with the right-angle corner. The included angle between the extending direction of the extending part and the first side or the second side ranges from 130 degrees to 140 degrees.

Description

TECHNICAL FIELD

[0001] The present invention relates to a design method of a pattern for optical proximity correction and a photomask pattern. BACKGROUND

[0002] In a semiconductor manufacturing process, when a specific pattern of elements (e.g. gate, pad, etc.) is to be formed on a substrate, a corresponding pattern is first designed in a computer system, then an optical proximity correction (OPC) is performed to generate a corrected pattern, and the corrected pattern is transferred to a photomask to form a photomask pattern. Subsequently, the photomask pattern is transferred to a material layer by a lithography step and an etching step.

[0003] However, for a pattern having a right-angled corner, the current OPC technique still cannot effectively solve the problem of corner rounding, and thus cannot accurately form the desired pattern in the material layer. SUMMARY

[0004] The present invention provides a pattern for optical proximity correction, which includes a T-shaped portion connected to a right-angled corner of a main portion.

[0005] The present invention provides a design method of a photomask pattern, in which a first pattern to be transferred to a material layer is corrected before performing optical proximity correction.

[0006] The pattern for optical proximity correction of the present invention includes a main portion and a T-shaped portion. The main portion has at least one right-angled corner, in which the right-angled corner is composed of a first side and a second side. The T-shaped portion includes a head portion and an extension portion, in which the extension portion is connected to the right-angled corner. The angle between the extension direction of the extension portion and the first side or the second side is between 130 degrees and 140 degrees.

[0007] In an embodiment of the pattern for optical proximity correction of the present invention, the extension portion extends outwardly toward the main portion.

[0008] In an embodiment of the pattern for optical proximity correction of the present invention, the T-shaped portion is a T-shaped groove, and the extension portion extends inwardly toward the main portion.

[0009] In an embodiment of the pattern for optical proximity correction of the present invention, the distance between the connection of the sidewall of the extension portion and the first side and the vertex of the right-angled corner is not more than 1 / 3 of the length of the first side.

[0010] In an embodiment of the pattern for optical proximity correction of the present application, the distance between the connection of the side wall of the extension and the vertex of the right angle corner and the length of the second side is no more than 1 / 3 of the length of the second side.

[0011] The method for designing a photomask pattern of the present application comprises the following steps. A first pattern to be transferred into a material layer is provided, wherein the first pattern comprises a main body part having at least one right angle corner, and the right angle corner is composed of a first side and a second side. The first pattern is modified to form a second pattern, wherein the second pattern comprises the main body part and a T-shaped part, the T-shaped part comprises a head part and an extension part, the extension part is connected with the right angle corner, and the angle between the extension direction of the extension part and the first side or the second side is between 130 degrees and 140 degrees. The second pattern is subjected to optical proximity correction to form a photomask pattern.

[0012] In an embodiment of the method for designing a photomask pattern of the present application, the extension part extends outwardly toward the main body part.

[0013] In an embodiment of the method for designing a photomask pattern of the present application, the T-shaped part is a T-shaped groove, and the extension part extends inwardly toward the main body part.

[0014] In an embodiment of the method for designing a photomask pattern of the present application, the distance between the connection of the side wall of the extension part and the vertex of the right angle corner and the length of the first side is no more than 1 / 3 of the length of the first side.

[0015] In an embodiment of the method for designing a photomask pattern of the present application, the distance between the connection of the side wall of the extension part and the vertex of the right angle corner and the length of the second side is no more than 1 / 3 of the length of the second side.

[0016] Based on the above, in the method for designing a photomask pattern of the present application, before optical proximity correction is performed, a first pattern to be transferred into a material layer is modified to form a second pattern comprising a main body part and a T-shaped part. In the second pattern, the T-shaped part is connected with the right angle corner of the main body part, so that when the second pattern is subsequently subjected to optical proximity correction, the T-shaped part can be further modified, that is, the right angle corner of the main body part can be more finely modified to solve the problem of corner rounding. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flow chart of the method for designing a photomask pattern of an embodiment of the present application;

[0018] Figure 2 The schematic diagram of the first pattern of the first embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of the second pattern according to the first embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the modified pattern according to the first embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the first pattern according to the second embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the second pattern according to the second embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the modified pattern according to the second embodiment of the present invention.

[0024] Symbol Explanation

[0025] 20, 50: First pattern

[0026] 30, 60: Second pattern

[0027] 40, 70: Correct pattern

[0028] 100, 102, 104: Steps

[0029] 200, 500: Main body

[0030] 300, 600: T-shaped section

[0031] 300a: Head

[0032] 300b: Extension

[0033] 602: T-groove

[0034] CR: Right angle

[0035] CR1: Outer right angle

[0036] CR2: Inner right angle corner

[0037] D: Extension direction

[0038] L1, L2, L3: Length

[0039] P1, P2: Connection point

[0040] S1: First side

[0041] S2: Second side

[0042] V: Vertex

[0043] W: Width

[0044] θ1, θ2: included angle DETAILED DESCRIPTION

[0045] The embodiments are illustrated by way of example in the following without intent to limit the scope of the application. Further, the drawings are not drawn to scale and are for purposes of explanation only. Identical elements are denoted with identical reference numerals throughout the several views.

[0046] The terms "comprise", "include", "have" and the like are to be construed as open-ended terms, i.e., meaning "including, but not limited to".

[0047] When an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout.

[0048] In the present embodiment, the design method of a photomask pattern is used to form a photomask pattern, and after a photolithography step and an etching step are performed using a photomask having the photomask pattern, a desired pattern can be accurately formed in a material layer. This will be described in detail below.

[0049] Figure 1 Flowchart of the design method of a photomask pattern according to an embodiment of the present application.

[0050] Referring to Figure 1 , first, in step 100, a first pattern to be transferred to a material layer is provided. In the present embodiment, the first pattern corresponds to a target pattern to be formed in the material layer. When a photolithography step and an etching step are performed using a photomask, there will be a difference between the pattern formed in the material layer and the target pattern due to the optical proximity effect in the photolithography process or the loading effect in the etching step. Therefore, in the present embodiment, the first pattern is modified, and the modified first pattern is used to form a photomask pattern, so that the pattern formed in the material layer corresponds to the target pattern accurately. For example, the first pattern corresponding to the target pattern to be formed in the material layer can be input into a computer system to be modified.

[0051] In the present embodiment, as shown in Figure 2 , the first pattern 20 includes a rectangular main body portion 200. The main body portion 200 has four right-angled corners CR, and each right-angled corner CR is formed by two sides, and the right-angled corner CR has a vertex V. Taking the right-angled corner CR at the upper left corner in Figure 2 as an example, it is formed by a first side S1 and a second side S2.

[0052] Then, in step 102, the first pattern 20 is modified to form the second pattern 30. In this embodiment, the right-angled corners CR of the first pattern 20 can be modified in a computer system.

[0053] In this embodiment, as Figure 3 As shown, after modifying the first pattern 20, the resulting second pattern 30 includes a main body 200 and four T-shaped parts 300. Each of the four T-shaped parts 300 is connected to a right-angled corner CR of the main body 200. Each T-shaped part 300 includes a head 300a and an extension 300b, with the extension 300b connected to the right-angled corner CR. That is, the T-shaped part 300 is connected to the right-angled corner CR of the main body 200 with its head 300a facing outwards. Furthermore, the angle between the extension direction D of the extension 300b and the first side S1 or the second side S2 is between 130 and 140 degrees. In this embodiment, the angles θ1 and θ2 between the extension direction D of the extension 300b and the first side S1 and the second side S2 are both 135 degrees. That is, in this embodiment, the T-shaped part 300 can extend outwards from the vertex V of the right-angled corner CR along the angle bisector towards the main body 200.

[0054] In this embodiment, the distance between the connection point of the sidewall of the extension 300b and the side of the main body 200 and the vertex V of the right-angle corner CR does not exceed 1 / 3 of the length of the side. For example, such as Figure 3 As shown, the distance between the connection point P1 of the sidewall adjacent to the first side S1 of the extension 300b and the vertex V of the right-angled corner CR does not exceed 1 / 3 of the length L1 of the first side S1. Similarly, the distance between the connection point P2 of the sidewall adjacent to the second side S2 of the extension 300b and the vertex V of the right-angled corner CR does not exceed 1 / 3 of the length L2 of the second side S2. Furthermore, the width W and length L3 of the head 300a, and the length L4 of the side of the extension 300b must not be less than the minimum permissible length for subsequent optical proximity correction. That is, the dimensions of each side of the T-shaped portion 300 must not be less than the minimum permissible length for subsequent optical proximity correction. Therefore, the T-shaped portion 300 can be used for subsequent optical proximity correction.

[0055] Subsequently, in step 104, optical proximity correction is performed on the second pattern 30 to form a corrected pattern 40, such as... Figure 4The modified pattern 40 is the photo mask pattern formed on the photo mask subsequently. In this way, the design of the photo mask pattern of this embodiment is completed. In this embodiment, since the T-shaped portion 300 is connected to the right-angle corner CR of the main body portion 200, the T-shaped portion 300 can be further modified when the optical proximity correction is performed, i.e. the right-angle corner CR of the main body portion 200 can be more finely modified to solve the problem of corner rounding.

[0056] After the design of the photo mask pattern is completed, the modified pattern 40 can be transferred to the photo mask to form the photo mask pattern by generally known steps. Then, the photo mask pattern is transferred to a material layer by a photolithography step and an etching step to form the desired pattern in the material layer. In this embodiment, the first pattern 20 is pre-modified before the optical proximity correction is performed, and the modified pattern is further modified to form the photo mask pattern by the optical proximity correction, so that the pattern corresponding to the first pattern 20 can be accurately formed in the material layer.

[0057] In this embodiment, the first pattern 20 includes the rectangular main body portion 200, and the T-shaped portion 300 extends outwardly from the main body portion 200, but the present application is not limited thereto. In other embodiments, the target pattern (the first pattern) to be formed in the material layer can have other shapes, and the T-shaped portion can be a T-shaped groove extending inwardly from the main body portion.

[0058] Figure 5 A schematic view of a first pattern of a second embodiment of the present application. Figure 6 A schematic view of a second pattern of the second embodiment of the present application. Figure 7 A schematic view of a modified pattern of the second embodiment of the present application.

[0059] Please refer to Figure 5 , Figure 6 and Figure 7 In this embodiment, the first pattern 50 corresponding to the target pattern to be formed in the material layer includes an L-shaped main body portion 500. The main body portion 500 has five outer right-angle corners CR1 and one inner right-angle corner CR2. After the outer right-angle corners CR1 and the inner right-angle corner CR2 of the first pattern 50 are modified, the second pattern 60 is formed. The second pattern 60 includes the main body portion 500, five T-shaped portions 600 at the CR1 and one T-shaped groove 602 at the CR2. The design rules of the T-shaped portions 600 and the T-shaped groove 602 are the same as those of the T-shaped portion 300 in the first embodiment, and will not be repeated here.

[0060] In the present embodiment, the T-shaped groove 602 extends inwardly into the main body portion 500. In detail, the T-shaped groove 602 is connected to the inner right-angle corner CR2 of the main body portion 500 in a manner with the head portion facing inwardly. That is, in the present embodiment, the T-shaped groove 602 extends inwardly from the vertex of the inner right-angle corner CR2 along the angle bisector to the main body portion 500.

[0061] After the optical proximity correction is performed on the second pattern 60, a corrected pattern 70 is formed as a photomask pattern formed on the photomask.

[0062] In the present embodiment, since the T-shaped portion 600 is connected to the outer right-angle corner CR1 of the main body portion 500 and the T-shaped groove 602 is connected to the inner right-angle corner CR2 of the main body portion 500, when the optical proximity correction is performed, the T-shaped portion 600 and the T-shaped groove 602 can be further corrected, that is, more subtle correction can be performed on the outer right-angle corner CR1 and the inner right-angle corner CR2 of the main body portion 500 to solve the problem of corner rounding.

[0063] Although the present application has been disclosed with the above embodiments, it is not intended to limit the present application, and any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the appended claims.

Claims

1. A pattern for optical proximity correction, comprising: a main portion having at least one right angle corner, wherein the right angle corner is formed by a first side and a second side; and a T-shaped portion comprising a head portion and an extension portion, wherein the extension portion is connected to the right angle corner, wherein an angle between an extension direction of the extension portion and the first side or the second side is between 130 degrees and 140 degrees.

2. The pattern for optical proximity correction of claim 1, wherein the extension portion extends outwardly toward the main portion.

3. The pattern for optical proximity correction of claim 1, wherein the T-shaped portion is a T-shaped groove, and the extension portion extends inwardly toward the main portion.

4. The pattern for optical proximity correction of claim 1, wherein a distance between a connection of a sidewall of the extension portion and the first side and a vertex of the right angle corner is no more than 1 / 3 of a length of the first side.

5. The pattern for optical proximity correction of claim 1, wherein a distance between a connection of a sidewall of the extension portion and the second side and a vertex of the right angle corner is no more than 1 / 3 of a length of the second side.

6. A method of designing a photomask pattern, comprising: providing a first pattern to be transferred into a material layer, wherein the first pattern comprises a main portion having at least one right angle corner, and the right angle corner is formed by a first side and a second side; modifying the first pattern to form a second pattern, wherein the second pattern comprises the main portion and a T-shaped portion comprising a head portion and an extension portion, the extension portion is connected to the right angle corner, and wherein an angle between an extension direction of the extension portion and the first side or the second side is between 130 degrees and 140 degrees; and optically proximity correcting the second pattern to form a photomask pattern.

7. The method of designing a photomask pattern of claim 6, wherein the extension portion extends outwardly toward the main portion.

8. The method of designing a photomask pattern of claim 6, wherein the T-shaped portion is a T-shaped groove, and the extension portion extends inwardly toward the main portion.

9. The method of designing a photomask pattern of claim 6, wherein a distance between a connection of a sidewall of the extension portion and the first side and a vertex of the right angle corner is no more than 1 / 3 of a length of the first side.

10. The method of designing a photomask pattern of claim 6, wherein a distance between a connection of a sidewall of the extension portion and the second side and a vertex of the right angle corner is no more than 1 / 3 of a length of the second side. ​

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