TWI901110B - Pattern for optical proximity correction and designing method of photomask pattern - Google Patents

Abstract

Provided are a pattern for an optical proximity correction and a designing method of a photomask pattern. The pattern for an optical proximity correction includes a body pattern and an array pattern. The body pattern has at least one right-angled corner. The array pattern includes n×n sub-patterns and is disposed adjacent to the right-angled corner. At least one of the sub-patterns is located in the body pattern, and the sub-pattern located in the body pattern is a hole penetrating through the body pattern.

Description

Design method of pattern and mask pattern for optical proximity correction

The present invention relates to a design method for a pattern and a mask pattern for optical proximity correction (OPC).

In semiconductor manufacturing, to form specific device patterns (such as gates and pads) on a substrate, the corresponding pattern is first designed in a computer system. Optical Processing (OPC) is then performed to generate a modified pattern. This modified pattern is then transferred to a photomask to form a mask pattern. Subsequently, lithography and etching steps are used to transfer the mask pattern to the material layer.

However, for patterns with right-angled corners, existing OPC technology still cannot effectively solve the problem of corner rounding, and therefore cannot accurately form the desired pattern in the material layer.

The present invention provides a pattern for optical proximity correction, which includes a main pattern and an array pattern, wherein the array pattern is arranged at a right-angle corner adjacent to the main pattern.

The present invention provides a method for designing a mask pattern, wherein a first pattern to be transferred to a material layer is corrected before optical proximity correction is performed.

The pattern for optical proximity correction of the present invention includes a main pattern and an array pattern. The main pattern has at least one right-angled corner. The array pattern includes n×n sub-patterns arranged adjacent to the right-angled corner, at least one of which is located within the main pattern, and the sub-pattern located within the main pattern is an opening that penetrates the main pattern.

In one embodiment of the pattern for optical neighbor correction of the present invention, n≥1.

In one embodiment of the pattern for optical neighbor correction of the present invention, n>1, and a portion of the sub-pattern is located in the main pattern, while the remaining sub-pattern is located outside the main pattern.

In one embodiment of the pattern for optical neighbor correction of the present invention, the sub-patterns in the array pattern have the same size.

In one embodiment of the pattern for optical neighbor correction of the present invention, the sub-patterns in the array pattern have different sizes.

In one embodiment of the pattern for optical neighbor correction of the present invention, the sub-patterns in the array pattern have the same shape.

In one embodiment of the pattern for optical neighbor correction of the present invention, the sub-patterns in the array pattern have different shapes.

The method for designing a photomask pattern of the present invention includes the following steps: Providing a first pattern to be transferred to a material layer, wherein the first pattern includes a main pattern having at least one right-angled corner. Modifying the first pattern to form a second pattern, wherein the second pattern includes the main pattern and an array pattern, wherein the array pattern includes n×n sub-patterns arranged adjacent to the right-angled corner, at least one of the sub-patterns being located within the main pattern, and the sub-patterns within the main pattern are openings penetrating the main pattern. Optical proximity correction is performed on the second pattern to form a photomask pattern.

In one embodiment of the mask pattern design method of the present invention, n≥1.

In one embodiment of the mask pattern design method of the present invention, n>1, and a portion of the sub-patterns are located within the main pattern, while the remaining sub-patterns are located outside the main pattern.

In one embodiment of the mask pattern design method of the present invention, the sub-patterns in the array pattern have the same size.

In one embodiment of the mask pattern design method of the present invention, the sub-patterns in the array pattern have different sizes.

In one embodiment of the mask pattern design method of the present invention, the sub-patterns in the array pattern have the same shape.

In one embodiment of the mask pattern design method of the present invention, the sub-patterns in the array pattern have different shapes.

Based on the above, in the mask pattern design method of the present invention, before performing optical proximity correction, the first pattern to be transferred to the material layer is corrected to form a second pattern comprising a main pattern and an array pattern. In the second pattern, the array pattern is adjacent to the right-angled corners of the main pattern. Therefore, when performing optical proximity correction on the second pattern, further corrections can be made to the array pattern, that is, more subtle corrections can be made to the right-angled corners of the main pattern to solve the problem of corner rounding.

The following examples are illustrated in detail with accompanying figures. However, these examples are not intended to limit the scope of the present invention. Furthermore, the figures are for illustrative purposes only and are not drawn to scale. For ease of understanding, identical components will be labeled with the same reference numerals throughout the following description.

The terms "include", "including", "have", etc. used in this document are open terms, which means "including but not limited to".

When terms such as "first" and "second" are used to describe elements, they are only used to distinguish these elements from each other, and do not limit the order or importance of these elements. Therefore, in some cases, the first element can also be called the second element, and the second element can also be called the first element, and this does not deviate from the scope of the present invention.

In this embodiment, a mask pattern design method is used to form a mask pattern. After performing lithography and etching steps using a mask having the mask pattern, a desired pattern can be accurately formed in a material layer. This will be described in detail below.

FIG1 is a flow chart of a method for designing a mask pattern according to an embodiment of the present invention.

Referring to FIG. 1 , first, in step 100 , a first pattern to be transferred to the material layer is provided. In this embodiment, the first pattern corresponds to a target pattern to be formed in the material layer. When a photomask is used to perform a lithography step and a photolithography step, due to an optical proximity effect in the lithography process or a loading effect in the etching step, there will be a difference between the pattern formed in the material layer and the target pattern. Therefore, in this embodiment, the above-mentioned first pattern is corrected, and the corrected first pattern is used to form a photomask pattern so that the pattern formed in the material layer accurately corresponds to the target pattern. For example, the first pattern corresponding to the target pattern to be formed in the material layer can be input into a computer system for correction.

As shown in FIG2 , the first pattern 20 includes a main pattern 200. The main pattern 200 can have any shape and has at least one right-angled corner CR. FIG2 illustrates the main pattern 200 with a right-angled corner CR located at the upper right corner as an example, but the present invention is not limited thereto.

Then, in step 102, the first pattern is corrected to form a second pattern. In one embodiment, the right-angled corner CR of the first pattern 20 can be corrected in a computer system. After the first pattern 20 is corrected, the second pattern formed includes a main pattern 200 and an array pattern. The array pattern is set near the right-angled corner CR. The array pattern includes n×n sub-patterns, and n ≥ 1. The present invention does not limit the number of sub-patterns, as long as the number of sub-patterns does not affect the subsequent optical proximity correction. In addition, in the array pattern, at least one sub-pattern is located in the main pattern 200, and the sub-pattern located in the main pattern 200 is an opening that penetrates the main pattern 200.

As shown in FIG3 , after modifying the first pattern 20, the resulting second pattern 30 includes the main pattern 200 and an array pattern 300. The array pattern 300 is positioned adjacent to the right-angled corner CR. The array pattern 300 includes n×n sub-patterns, where n>1. When n>1, the sub-patterns of the array pattern 300 surround the right-angled corner CR, with some sub-patterns located within the main pattern 200 and the remaining sub-patterns located outside the main pattern 200.

In Figure 3 , taking n=3 as an example, array pattern 300 is composed of nine sub-patterns, and these sub-patterns surround a right-angled corner CR. Furthermore, the nine sub-patterns of array pattern 300 include four sub-patterns 300a located within main pattern 200 and five sub-patterns 300b located outside main pattern 200, but the present invention is not limited to this. Sub-pattern 300a is an opening that penetrates main pattern 200, while sub-pattern 300b is a solid pattern. In other embodiments, array pattern 300 only needs to include at least one sub-pattern 300b located outside main pattern 200. Furthermore, the present invention does not restrict the positions of the sub-patterns 300a and 300b and the pitch between these sub-patterns, as long as the array pattern 300 is adjacent to the right-angled corner CR.

In the embodiment shown in FIG3 , the nine sub-patterns of the array pattern 300 are of different sizes, but the present invention is not limited thereto. The present invention does not restrict the sizes of these sub-patterns, as long as they are no smaller than the minimum allowable size for subsequent optical proximity correction and do not affect the optical proximity correction due to excessive size. Furthermore, in the embodiment shown in FIG3 , the nine sub-patterns of the array pattern 300 are all square in shape, but the present invention is not limited thereto. In other embodiments, the sub-patterns may be of any other shape, and the shapes of these sub-patterns may be different from one another.

In another embodiment, when n=1, as shown in FIG6 , after modifying the first pattern 20, the resulting second pattern 60 has an array pattern 600 that is a 1×1 array pattern and includes one sub-pattern 602. Sub-pattern 602 is located within the main pattern 200 and adjacent to the right-angled corner CR. Sub-pattern 602 is an opening that penetrates the main pattern 200.

Next, in step 104, optical proximity correction is performed on the second pattern (e.g., second pattern 30 in FIG. 3 ) to form a corrected pattern. The corrected pattern is the mask pattern subsequently formed on the mask. This completes the design of the mask pattern of this embodiment.

In this embodiment, since the array pattern is located at a right-angled corner adjacent to the main pattern and at least one sub-pattern in the array pattern is located within the main pattern, further corrections can be made to the array pattern during optical proximity correction. This means that more subtle corrections can be made to the right-angled corners of the main pattern to resolve the corner rounding issue.

After the mask pattern is designed, the modified pattern can be transferred to the mask through commonly known steps to form the mask pattern. Subsequently, the mask pattern is transferred to the material layer through lithography and etching steps to form the desired pattern in the material layer. In this embodiment, the first pattern is pre-corrected before optical proximity correction is performed, and the corrected pattern is then used to form the mask pattern through optical proximity correction. This allows a pattern corresponding to the first pattern to be accurately formed in the material layer.

The mask pattern design method of the present invention can be used for target patterns (first patterns) of various shapes. This is described in detail below.

FIG4 is a schematic diagram of a second pattern according to the second embodiment of the present invention.

Referring to FIG. 4 , in this embodiment, the first pattern corresponding to the target pattern to be formed in the material layer is a rectangular pattern, wherein the main pattern 400 has four rectangular corners CR. Furthermore, before performing optical proximity correction, the rectangular corners of the first pattern are corrected. After the correction of the rectangular corners of the first pattern, in the resulting second pattern 40, an array pattern 402 comprising 3×3 sub-patterns is positioned adjacent to the two right-hand corners CR, and these sub-patterns simultaneously surround the two right-hand corners CR. In this embodiment, the nine sub-patterns of the array pattern 402 include two sub-patterns 402a located within the main pattern 400 and seven sub-patterns 402b located outside the main pattern 400. Sub-pattern 402a is an opening penetrating through main pattern 400, while sub-pattern 402b is a solid pattern. The design rules of array pattern 402 are the same as those of the first embodiment and will not be repeated here.

For the two right-angled corners CR located on the left side, another array pattern 402 can be set in the same manner. In other embodiments, the array patterns can be set in different manners for the right-angled corners located on the left and right sides, and the present invention is not limited thereto.

In this embodiment, since the array pattern 402 is located adjacent to the right-angled corner CR of the main pattern 400, when performing optical proximity correction on the second pattern 40, further correction can be performed on the array pattern 402. In other words, a more subtle correction can be made to the right-angled corner CR of the main pattern 400 to solve the corner rounding problem.

FIG5 is a schematic diagram of the second pattern of the third embodiment of the present invention.

Referring to FIG. 5 , in this embodiment, a first pattern corresponding to a target pattern to be formed in a material layer comprises an L-shaped pattern, wherein a main pattern 500 has at least one outer right-angle corner CR1 and one inner right-angle corner CR2. Furthermore, before performing optical proximity correction, the outer right-angle corner CR1 and the inner right-angle corner CR2 of the first pattern are corrected. After correcting the outer right-angle corner CR1 and the inner right-angle corner CR2 of the first pattern, in the resulting second pattern 50, an array pattern 502 comprising 3×3 sub-patterns is positioned adjacent to the outer right-angle corner CR1 and the inner right-angle corner CR2, with these sub-patterns surrounding both the outer right-angle corner CR1 and the inner right-angle corner CR2. In this embodiment, the nine sub-patterns of array pattern 502 include three sub-patterns 502a located within main pattern 500 and six sub-patterns 502b located outside main pattern 500. Sub-patterns 502a are openings that penetrate main pattern 500, while sub-patterns 502b are solid patterns. The design rules for array pattern 502 are the same as those in the first embodiment and will not be repeated here.

In this embodiment, since the array pattern 502 is located adjacent to the outer right-angle corner CR1 and the inner right-angle corner CR2 of the main pattern 500, when performing optical proximity correction on the second pattern 50, further corrections can be made to the array pattern 502. Specifically, more subtle corrections can be made to the outer right-angle corner CR1 and the inner right-angle corner CR2 of the main pattern 500 to resolve the corner rounding problem.

Although the present invention has been disclosed above by way of embodiments, they are not intended to limit the present invention. Any person having ordinary skill in the art may make slight modifications and improvements 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 attached patent application.

20: First pattern 30, 40, 50, 60: Second pattern 100, 102, 104: Steps 200, 400, 500: Main pattern 300, 402: Array pattern 300a, 300b, 402a, 402b, 502a, 502b, 602: Sub-patterns CR: Right corner CR1: Outer right corner CR2: Inner right corner

Figure 1 is a flow chart of a method for designing a mask pattern according to an embodiment of the present invention. Figure 2 is a schematic diagram of a first pattern according to the first embodiment of the present invention. Figure 3 is a schematic diagram of a second pattern according to the first embodiment of the present invention. Figure 4 is a schematic diagram of a second pattern according to the second embodiment of the present invention. Figure 5 is a schematic diagram of a second pattern according to the third embodiment of the present invention. Figure 6 is a schematic diagram of a second pattern according to another embodiment of the present invention.

100, 102, 104: Steps

Claims (14)

A pattern for optical proximity correction includes: a main pattern having at least one right-angled corner; and an array pattern comprising n×n sub-patterns disposed adjacent to the right-angled corner, wherein at least one of the sub-patterns is located within the main pattern, and the sub-patterns within the main pattern are apertures penetrating the main pattern. A pattern for optical proximity correction as claimed in claim 1, wherein n≥1. A pattern for optical proximity correction as described in claim 2, wherein n>1, and a portion of the sub-pattern is located in the main pattern, and the remaining sub-pattern is located outside the main pattern. A pattern for optical proximity correction as described in claim 1, wherein the sub-patterns in the array pattern have the same size. The pattern for optical proximity correction as claimed in claim 1, wherein the sub-patterns in the array pattern have different sizes. A pattern for optical neighbor correction as described in claim 1, wherein the sub-patterns in the array pattern have the same shape. A pattern for optical proximity correction as described in claim 1, wherein the sub-patterns in the array pattern have different shapes. A method for designing a photomask pattern comprises: Providing a first pattern to be transferred to a material layer, wherein the first pattern comprises a main pattern having at least one right-angled corner; Changing the first pattern to form a second pattern, wherein the second pattern comprises the main pattern and an array pattern, wherein the array pattern comprises n×n sub-patterns disposed adjacent to the right-angled corner, at least one of the sub-patterns being located within the main pattern, and each sub-pattern within the main pattern being an opening penetrating the main pattern; and Performing optical proximity correction on the second pattern to form a photomask pattern. The method for designing a mask pattern as described in claim 8, wherein n≥1. The method for designing a mask pattern as described in claim 9, wherein n>1, and a portion of the sub-patterns are located in the main pattern, and the remaining sub-patterns are located outside the main pattern. The method for designing a mask pattern as described in claim 8, wherein the sub-patterns in the array pattern have the same size. The method for designing a mask pattern as described in claim 8, wherein the sub-patterns in the array pattern have different sizes. The method for designing a mask pattern as described in claim 8, wherein the sub-patterns in the array pattern have the same shape. The method for designing a mask pattern as described in claim 8, wherein the sub-patterns in the array pattern have different shapes.