Method for optimizing quality and size of contact hole pattern in mask

Abstract

The invention relates to mask manufacturing, in particular to a method for optimizing the quality and size of a contact hole pattern in a mask, which comprises the following steps of: converting the contact hole pattern into a format file which can be identified by a photoetching machine, and confirming a target photoetching light beam corresponding to the edge of the contact hole pattern; the energy output proportion of the target photoetching light beam is modified, the actual energy output of the target photoetching light beam is improved, and the quality and size of the contact hole pattern are optimized; according to the technical scheme provided by the invention, the defects of poor pattern quality and small pattern size after photoetching of the contact hole pattern with small design size in the prior art can be effectively overcome.

Description

Technical Field

[0001] The invention relates to mask manufacturing, and in particular to a method for optimizing the quality and size of contact hole patterns in a mask. Background Art

[0002] The principle of mask production is that the photolithography machine uses direct laser exposure to lithograph various circuit patterns on a substrate with photoresist, and then goes through back-end development, etching, stripping, measurement and repair processes to make the lithographed patterns perfectly presented on the substrate. This is the basic process of mask production.

[0003] However, the lithography effect of the pattern on the mask is limited by the lithography accuracy of the lithography machine. When the width of the pattern line seam is small, the lithography effect of the pattern will be poor, especially for the contact hole pattern. For example, when Mycronic's P series lithography machine lithography contact hole patterns smaller than 2.3μm*2.3μm, the final effect is that the hole is not a square, and its four corners will have obvious rounded corners and deformation problems, such as Figure 5 As shown, the pattern quality is poor and the pattern size is small. In severe cases, the square hole may be made into a circular hole, which will have a great impact on the quality of the mask product. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the above-mentioned shortcomings of the prior art, the present invention provides a method for optimizing the quality and size of contact hole patterns in a mask, which can effectively overcome the defects of the prior art in that the pattern quality of contact hole patterns with smaller design sizes is poor and the pattern size is small after photolithography.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A method for optimizing the quality and size of contact hole patterns in a mask, comprising the following steps:

[0009] S1. Convert the contact hole pattern into a format file that can be recognized by the photolithography machine, and confirm the target photolithography beam corresponding to the edge of the contact hole pattern;

[0010] S2. Modify the energy output ratio of the target photolithography beam, increase the actual energy output of the target photolithography beam, and optimize the quality and size of the contact hole pattern.

[0011] Preferably, converting the contact hole pattern into a format file recognizable by a lithography machine and determining a target lithography beam corresponding to an edge of the contact hole pattern in S1 includes:

[0012] Convert the contact hole pattern into a format file that can be recognized by the photolithography machine, mark the photolithography beam corresponding to each area in the contact hole pattern, and confirm the target photolithography beam corresponding to the edge of the contact hole pattern.

[0013] Preferably, the quality and dimensional accuracy of the contact hole pattern are most closely correlated with the target photolithography beam corresponding to the edge of the contact hole pattern. If the actual energy output of the target photolithography beam corresponding to the edge of the contact hole pattern is low, the effect of the contact hole pattern obtained after photolithography will be very poor, and the size will also be much smaller.

[0014] Preferably, modifying the energy output ratio of the target lithography beam in S2 to increase the actual energy output of the target lithography beam and optimize the quality and size of the contact hole pattern includes:

[0015] S21, first confirming the relationship between the energy output ratio of each lithography beam in the lithography machine and the actual energy output, then testing the optimal energy output corresponding to the designed CD values ​​of different contact hole patterns, and constructing a relationship table between the designed CD values ​​of different contact hole patterns and the optimal energy output ratio of each lithography beam;

[0016] S22, obtaining a corresponding optimal energy output ratio from a relationship table according to a designed CD value of the contact hole pattern and a target lithography beam;

[0017] S23. Modify the energy output ratio of the target photolithography beam according to the optimal energy output ratio, improve the actual energy output of the target photolithography beam, and optimize the quality and size of the contact hole pattern.

[0018] Preferably, in S23, modifying the energy output ratio of the target lithography beam according to the optimal energy output ratio, improving the actual energy output of the target lithography beam, and optimizing the quality and size of the contact hole pattern includes:

[0019] By beam scaling, the energy output ratio of the target lithography beam is adjusted to the optimal energy output ratio, thereby improving the actual energy output of the target lithography beam and optimizing the quality and size of the contact hole pattern.

[0020] (3) Beneficial effects

[0021] Compared with the prior art, the method for optimizing the quality and size of the contact hole pattern in the mask provided by the present invention addresses the problem that due to the different lithography accuracy of the lithography machine, the pattern quality of the contact hole pattern with a smaller design size is poor after lithography by a low-end lithography machine, and the resulting pattern is not a square hole but a quasi-circular hole, and the pattern size is relatively small. The present invention does not require the use of higher-end lithography equipment with higher lithography accuracy. It only needs to confirm the designed CD value of the contact hole pattern and the target lithography beam corresponding to the edge of the contact hole pattern during lithography, and modify the energy output ratio of the target lithography beam. By increasing the lithography energy intensity at the edge of the contact hole pattern, the quality and size of the pattern are effectively optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0023] Figure 1 It is a schematic diagram of the process of the present invention;

[0024] Figure 2 A schematic diagram of the photolithography beam corresponding to each region in the contact hole pattern marked in the present invention;

[0025] Figure 3 This is a result diagram of the optimal energy output corresponding to the designed CD values ​​of different contact hole patterns tested in the present invention;

[0026] Figure 4 This is a comparison diagram of the patterns obtained by photolithography of the contact hole pattern using the technical solution of the present invention;

[0027] Figure 5 This is a comparison chart showing the impact of pattern design size on pattern quality when existing photolithography machines are performing photolithography on contact hole patterns. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] A method for optimizing the quality and size of contact hole patterns in a mask, such as Figure 1As shown, S1, converting the contact hole pattern into a format file that can be recognized by the lithography machine, and confirming the target lithography beam corresponding to the edge of the contact hole pattern, specifically including:

[0030] Convert the contact hole pattern into a format file that can be recognized by the lithography machine, and mark the lithography beam corresponding to each area in the contact hole pattern (such as Figure 2 and confirm that the edge of the contact hole pattern corresponds to the target lithography beam.

[0031] The lithography machine used in mask manufacturing is a laser direct exposure type. The laser light route of each lithography machine is composed of multiple beams of light, each beam of light is called a beam (lithography beam). If there are 5 groups of beams, they can be called beam1, beam2,..., beam5. All the patterns to be photolithographic are lithographed by these 5 beams, and the actual energy output of each beam determines the pattern lithography effect.

[0032] In the technical solution of this application, the quality and dimensional accuracy of the contact hole pattern are most correlated with the target lithography beam corresponding to the edge of the contact hole pattern ( Figure 2 (In this case, beam2 and beam4 have the greatest impact on the quality and dimensional accuracy of the contact hole patterns.) If the actual energy output of the target lithography beam corresponding to the edge of the contact hole pattern is low, the effect of the contact hole pattern obtained after lithography will be very poor, and the size will also be much smaller.

[0033] S2. Modify the energy output ratio of the target lithography beam (under normal circumstances, this parameter is fixed and does not change, which can ensure the stability of the equipment) to improve the actual energy output of the target lithography beam and optimize the quality and size of the contact hole pattern. Specifically, it includes:

[0034] S21, first confirm the relationship between the energy output ratio of each lithography beam in the lithography machine and the actual energy output, and then test the optimal energy output corresponding to the designed CD value of different contact hole patterns (such as Figure 3 As shown), a relationship table between the designed CD values ​​of different contact hole patterns and the optimal energy output ratio of each lithography beam is constructed;

[0035] S22, obtaining a corresponding optimal energy output ratio from a relationship table according to a designed CD value of the contact hole pattern and a target lithography beam;

[0036] S23. Modify the energy output ratio of the target photolithography beam according to the optimal energy output ratio, improve the actual energy output of the target photolithography beam, and optimize the quality and size of the contact hole pattern.

[0037] Specifically, in S23, the energy output ratio of the target lithography beam is modified according to the optimal energy output ratio, the actual energy output of the target lithography beam is increased, and the quality and size of the contact hole pattern are optimized, including:

[0038] By beam scaling, the energy output ratio of the target lithography beam is adjusted to the optimal energy output ratio, thereby improving the actual energy output of the target lithography beam and optimizing the quality and size of the contact hole pattern.

[0039] It is worth noting that the technical solution of this application can only be used when simple hole patterns are used and a small number of beam types are used. Complex patterns will result in a larger CD range for the entire page or abnormal stripes.

[0040] like Figure 4 As shown in FIG, a comparison diagram of the patterns obtained by photolithography of the contact hole pattern using the technical solution of the present invention is shown. Through the comparison, it can be seen that the corners of the pattern obtained by photolithography before modifying the energy output ratio are severely deformed, and obvious rounded corners appear. After increasing the actual energy output, the resolution of the pattern corners is significantly improved.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for optimizing the quality and size of contact hole patterns in a mask, characterized by: The following steps are involved: S1. Convert the contact hole pattern into a format file that can be recognized by the photolithography machine, and confirm the target photolithography beam corresponding to the edge of the contact hole pattern; S2. Modify the energy output ratio of the target photolithography beam, increase the actual energy output of the target photolithography beam, and optimize the quality and size of the contact hole pattern.

2. The method for optimizing the quality and size of contact hole patterns in a mask according to claim 1, wherein: In S1, the contact hole pattern is converted into a format file that can be recognized by the lithography machine, and the target lithography beam corresponding to the edge of the contact hole pattern is confirmed, including: Convert the contact hole pattern into a format file that can be recognized by the photolithography machine, mark the photolithography beam corresponding to each area in the contact hole pattern, and confirm the target photolithography beam corresponding to the edge of the contact hole pattern.

3. The method for optimizing the quality and size of contact hole patterns in a mask according to claim 2, wherein: The quality and dimensional accuracy of the contact hole pattern are most closely related to the target photolithography beam corresponding to the edge of the contact hole pattern. If the actual energy output of the target photolithography beam corresponding to the edge of the contact hole pattern is low, the effect of the contact hole pattern obtained after photolithography will be very poor, and the size will also be much smaller.

4. The method for optimizing the quality and size of contact hole patterns in a mask according to claim 1, wherein: In S2, the energy output ratio of the target lithography beam is modified to increase the actual energy output of the target lithography beam and optimize the quality and size of the contact hole pattern, including: S21, first confirming the relationship between the energy output ratio of each lithography beam in the lithography machine and the actual energy output, then testing the optimal energy output corresponding to the designed CD values ​​of different contact hole patterns, and constructing a relationship table between the designed CD values ​​of different contact hole patterns and the optimal energy output ratio of each lithography beam; S22, obtaining a corresponding optimal energy output ratio from a relationship table according to a designed CD value of the contact hole pattern and a target lithography beam; S23. Modify the energy output ratio of the target photolithography beam according to the optimal energy output ratio, improve the actual energy output of the target photolithography beam, and optimize the quality and size of the contact hole pattern.

5. The method for optimizing the quality and size of contact hole patterns in a mask according to claim 4, wherein: In S23, the energy output ratio of the target lithography beam is modified according to the optimal energy output ratio, the actual energy output of the target lithography beam is improved, and the quality and size of the contact hole pattern are optimized, including: By beam scaling, the energy output ratio of the target lithography beam is adjusted to the optimal energy output ratio, thereby improving the actual energy output of the target lithography beam and optimizing the quality and size of the contact hole pattern.

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