Optical proximity correction method and method for manufacturing a mask including the method

Abstract

This disclosure provides an optical proximity correction method and a method for manufacturing a mask. The optical proximity correction method includes: extracting a first pattern from a pattern mask; performing photolithography on at least a portion of the first pattern to form a first first pattern; forming the first first pattern at the location where the first pattern is formed; and performing correction on the pattern mask on which the first first pattern is formed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an optical proximity correction method and a method of manufacturing a mask including the same. BACKGROUND

[0002] Generally, a photolithography technique is a fundamental technique that leads to high integration of semiconductor devices by forming a semiconductor pattern on a wafer (e.g., a semiconductor substrate) using light. For example, in photolithography, a photoresist, i.e., a material having a solubility that varies according to exposure light (e.g., ultraviolet rays, an electron beam, or X-rays) irradiated thereon, can be coated on a semiconductor substrate at a position where a pattern is to be formed, e.g., a semiconductor film, an insulating film, a conductive film, etc., a predetermined portion of the photoresist can be exposed to light by using a photomask, and then an exposed portion of the photoresist, which exhibits high solubility in response to a developer, can be removed, thereby forming a photoresist pattern. Portions of the semiconductor film, the insulating film, the conductive film, etc., on the semiconductor substrate that are exposed through the photoresist pattern can be removed by an etching process, thereby forming a desired pattern, e.g., a semiconductor pattern, on the semiconductor substrate.

[0003] For example, an electron beam device can be used as an exposure device that forms a photoresist pattern using a photomask. However, an electron beam emitted from the electron beam device can be scattered in the photoresist and the layer thereunder, thereby affecting a critical dimension (CD) and fidelity of the photoresist pattern and the resulting semiconductor pattern. That is, an electron beam exposure method is a method of directly exposing an actual photoresist through a photomask, rather than a method of performing exposure, e.g., by using a stepper as a medium.

[0004] For example, in the electron beam exposure method, an area to be exposed is divided into small pixels, and pixels corresponding to pattern data can be filled by an electron beam according to a pixel size. However, as the integration of semiconductor devices increases, the improvement effect of both the depth of focus and the resolution can be reduced in irregularly arranged patterns, which are common in logic devices such as microprocessors.

[0005] For example, when a pattern having a numerical value close to a resolution limit is formed, an optical proximity effect can occur, i.e., a pattern actually formed on a semiconductor substrate is different from a design pattern. Due to the difference between the design pattern and the actually formed pattern, for example, the performance of manufacturing can be significantly degraded compared to the performance expected from the design. Therefore, in response to the pattern difference (i.e., a distortion phenomenon) that occurs at the resolution limit in the photolithography process, optical proximity correction (OPC) is performed in order to adjust (e.g., compensate for) the difference, so that a fine pattern of a photomask on a wafer is properly completed as designed. SUMMARY

[0006] According to an aspect of an embodiment, there is provided an optical proximity correction method, the method including: extracting a first pattern from a pattern mask; performing lithography on at least a portion of the first pattern to form a first first pattern; forming the first first pattern at a location where the first pattern is formed; and performing correction on the pattern mask on which the first first pattern is formed.

[0007] According to an aspect of an embodiment, there is provided an optical proximity correction method, the method including: extracting a first pattern and a second pattern from a pattern mask; performing lithography on at least a portion of the first pattern to form a first first pattern; performing lithography on at least a portion of the second pattern to form a second first pattern; forming the first first pattern at a location where the first pattern is formed; forming the second first pattern at a location where the second pattern is formed; and performing correction on the pattern mask on which the first first pattern and the second first pattern are formed.

[0008] According to an aspect of an embodiment, there is provided a method of manufacturing a mask, the method including: manufacturing a pattern mask having a designed layout; performing lithography on at least a portion of a first pattern in the pattern mask to form a first first pattern; forming the first first pattern at a location where the first pattern is formed; performing correction on the pattern mask on which the first first pattern is formed to correct an optical proximity effect; and performing mask tape-out (MTO) on the pattern mask on which the optical proximity effect has been corrected. BRIEF DESCRIPTION OF DRAWINGS

[0009] Features will become apparent to those of ordinary skill in the art by the following detailed description of example embodiments with reference to the drawings, in which:

[0010] Figure 1 A plurality of patterns including object patterns before performing lithography is illustrated.

[0011] Figure 2 A plurality of patterns including object patterns on which lithography has been performed is illustrated.

[0012] Figure 3 Patterns of some regions extracted according to an optical proximity correction method according to some embodiments are illustrated before performing lithography.

[0013] Figure 4 Patterns obtained after performing lithography on some patterns extracted according to an optical proximity correction method according to some embodiments are illustrated.

[0014] Figure 5 is a flowchart showing a method of manufacturing a mask including an optical proximity correction method according to some embodiments.

[0015] Figure 6 Operation S300 of Figure 5 is illustrated.

[0016] Figure 7 It shows Figure 5 Operation S400.

[0017] Figure 8 yes Figure 7 A magnified view of region R5.

[0018] Figure 9 yes Figure 8 A magnified view of region R6.

[0019] Figure 10 It shows Figure 5 Operation of S500.

[0020] Figure 11 yes Figure 10 A magnified view of region R6-2.

[0021] Figure 12 It shows Figure 5 The operation of S600.

[0022] Figure 13 yes Figure 12 A magnified view of region R6-3. Detailed Implementation

[0023] In the following text, reference will be made to Figures 1 to 13 This describes an optical proximity correction method according to some implementations.

[0024] Figure 1 An example is shown of multiple patterns including an object pattern prior to photolithography.

[0025] Reference Figure 1 Multiple preliminary patterns 1 can be formed on a substrate. The multiple preliminary patterns 1 can include multiple preliminary object patterns 100 on the substrate to be photolithographically processed. For example, as... Figure 1 As shown, the plurality of preliminary object patterns 100 may be spaced apart from each other in a matrix pattern, for example, along the X and Y directions. The preliminary object patterns 100 may include two or more materials with different structures formed under the mask. However, this disclosure is not limited thereto, and the preliminary object patterns 100 may include only one material.

[0026] As the preliminary object pattern 100 becomes more refined, optical proximity effect (OPE) may occur due to the influence between adjacent preliminary object patterns 100 during the photolithography process. To overcome this drawback, i.e. OPE, it is necessary to suppress the occurrence of OPE by correcting the pattern layout on the mask that is transferred to form the preliminary object pattern 100.

[0027] It is assumed that the lithography described below is a reverse lithography technique (ILT). However, the lithography used in the optical proximity correction method according to some embodiments is not limited to ILT.

[0028] The ILT described below can be performed with respect to all of the preliminary patterns 1 including the preliminary object pattern 100. Reference will be made to Figure 2 A description will be given of a state after the ILT is performed with respect to all of the initial patterns 1 including the initial object pattern 100.

[0029] Figure 2 A plurality of patterns including object patterns on which lithography has been performed is shown.

[0030] Reference will be made to Figure 2 After the lithography is performed with respect to all of the preliminary patterns 1 including the preliminary object pattern 100, a plurality of patterns 2 including object patterns 200 that have undergone lithography can be formed. That is, after the lithography is performed with respect to all of the preliminary patterns 1 including the preliminary object pattern 100, the preliminary object pattern 100 can be converted into the object pattern 200 that has undergone lithography, respectively. In this case, the lithography is performed with respect to all of the preliminary patterns 1 including the preliminary object pattern 100, so that a database of optical proximity correction (OPC) can be generated in various ways regardless of a topographical effect on each pattern. Figure 1 Figure 1 Figure 1

[0031] Generally, when the lithography is performed with respect to all of the preliminary patterns including the preliminary object pattern, resources (e.g., power, etc.) can be excessively consumed during a process of performing the OPC method. In addition, since mask shapes for the preliminary object patterns can be different from each other, the resulting object patterns obtained after the lithography is performed can be deteriorated in consistency.

[0032] Therefore, for example, unlike the lithography performed with respect to all of the patterns, in the OPC method according to the embodiments, the lithography is performed by extracting a repeated object pattern, so that excessive resource waste is prevented and consistency of the object patterns obtained after the lithography is performed is improved. Hereinafter, the OPC method according to some embodiments and a method of manufacturing a mask including the same will be described. In addition, it is noted that the extracted pattern refers to a portion of a pattern from a repeated pattern, and can be set to a minimum repeating unit or a range expanded from the minimum repeating unit.

[0033] Figure 3 A pattern extraction in the OPC method according to some embodiments is shown with respect to some regions among the plurality of preliminary object patterns 100 before the lithography is performed. Figure 1

[0034] Reference will be made to Figure 3 ​​​​, each region with a unique pattern that repeats can exist in a preliminary pattern 1 including a preliminary object pattern 100 to be subjected to photolithography. Such regions can be determined, for example, by visual observation or computer software, for example, to re-determine objects for photolithography. For example, as shown in Figure 3 the patterns in the first to fourth regions R1 to R4 can be extracted, for example, via a mask or via computer simulation, for example, separating the patterns in the first to fourth regions R1 to R4 from other patterns.

[0035] For example, the preliminary object pattern 100 of the first region R1, the second region R2, the third region R3, and the fourth region R4 can have different patterns, for example, different spacings or pattern arrangements within each region. For example, the pattern of the preliminary object pattern 100 within each of the first to fourth regions R1 to R4 can be the same, for example, having the same shape.

[0036] Subsequently, as will be described in more detail below with reference to Figures 5-13 , photolithography can be performed by the OPC method according to some embodiments only on regions with the preliminary object pattern 100 with the same unique pattern, for example, the first region R1, the second region R2, the third region R3, and / or the fourth region R4. For example, photolithography can be performed, for example, only on the first to fourth regions R1 to R4 of the preliminary object pattern 100, rather than on all of the preliminary object pattern 100, as will be described in more detail below. Figure 3

[0037] Figure 4 shows a pattern obtained after performing photolithography on some of the preliminary object pattern 100, for example, on the extracted preliminary object pattern 100 of the Figure 3 according to the OPC method according to some embodiments.

[0038] Referring to Figure 4 , photolithography is performed on each of the first region R1, the second region R2, the third region R3, and the fourth region R4 with the same unique pattern among the preliminary pattern 1 including the preliminary object pattern 100 of Figure 3 . By photolithography, a first first region R1-1, a second first region R2-1, a third first region R3-1, and a fourth first region R4-1 with a resulting object pattern 200 subjected to photolithography can be formed.

[0039] Thus, for example, due to performing photolithography on the extracted patterns rather than on all of the patterns, the run time of photolithography can be reduced, and the uniformity of the patterns subjected to photolithography can also be improved. In addition, resources for performing photolithography can also be reduced.

[0040] Hereinafter, the optical proximity correction method according to some embodiments will be described in detail.​

[0041] Figure 5 is a flowchart showing a method of manufacturing a mask including an OPC method according to some embodiments. Figure 6 Operation S300 of Figure 5 is shown in FIG. 3. Figure 7 Operation S400 of Figure 5 is shown in FIG. 4. Figure 8 is an enlarged view of a region R5 of Figure 7 is an enlarged view of a region R6 of Figure 9 Operation S500 of Figure 8 is shown in FIG. 5. Figure 10 is an enlarged view of a region R6-2 of Figure 5 Operation S600 of Figure 11 is shown in FIG. 6. Figure 10 is an enlarged view of a region R6-3 of Figure 12 Operation S600 of Figure 5 is shown in FIG. 6. Figure 13 is an enlarged view of a region R6-3 of Figure 12 is shown in FIG. 6.

[0042] Referring to Figures 5 to 13 , a layout design (operation S100) can be provided first, for example, a layout of the preliminary object pattern 100 in Figure 1 . Thereafter, objects in the designed layout can be determined (operation S200), for example, as described with reference to Figure 3 , regions having a repeated unique pattern can be determined among the preliminary object pattern 100.

[0043] Then, according to some embodiments, the same (e.g., repeated) unique pattern can be analyzed by an OPC method (operation S300). For example, the repeated unique pattern can be analyzed with respect to the design layout 3 of Figure 6 . At this time, the size of the region in which the unique pattern is determined can be arbitrarily determined.

[0044] Subsequently, the area of the analyzed same unique pattern is reduced (operation S400). The result obtained by reducing the area of the portion having the same unique pattern with respect to the design layout 3 of Figure 6 corresponds to the pattern 4 of Figure 7 . For example, the reduction rate can be 0.2% of the original area.

[0045] For example, the fifth region R5 among the compressed portion in Figure 8 will be described with reference to the enlarged view in Figure 7 . As shown in Figure 8 , in the fifth region R5, the preliminary object pattern 100 can be disposed (i.e., before undergoing photolithography). For example, in Figure 9The image shows a magnified view of a portion of the fifth region R5 (e.g., the sixth region R6). That is, as shown in... Figure 9 As seen in the enlarged view of the sixth region R6, a layout with the same unique pattern can exist in the fifth region R5 before photolithography is performed.

[0046] Next, photolithography is performed only on the portion with the same unique pattern (e.g., the fifth region R5), and the area of ​​this portion is reduced in operation S400. Figure 10 The image shows the state after photolithography was performed on a portion (e.g., the fifth region R5) with the same unique pattern (whose area has been reduced in operation S400).

[0047] In the fifth second region R5-2, which includes the object pattern subjected to photolithography, such as Figure 10 As shown, the sixth region R6 (in Figure 9 The original shape of the layout pattern (shown in the image) may be deformed. For example, it can be distorted by photolithography. Figure 9 The sixth region R6 (i.e., before photolithography) is transformed into... Figure 10 The sixth second region R6-2 is a part of the fifth second region R5-2. The following will refer to... Figure 11 A more detailed explanation of the sixth and second regions, R6-2.

[0048] Figure 11 It shows Figure 10 An enlarged view of the sixth second region R6-2. As shown in the enlarged view of the sixth second region R6-2, the object pattern subjected to photolithographic deformation can be formed into a pattern for OPC.

[0049] Subsequently, photolithography is performed on the portions where the photolithography has been repeated, and this photolithography has only been performed on the same unique pattern (operation S600). Therefore, photolithography can be performed on all portions where the unique pattern is repeated, such as... Figure 12 As in the fifth and third region R5-3. Figure 13 The diagram shows an enlarged view of the sixth third region R6-3, which is part of the fifth third region R5-3. For example, portions of the repeating pattern that has undergone lithography and OPC (i.e., the extracted pattern) can be formed (e.g., implemented) within the remaining pattern layout, for example, as performed... Figure 5 The installation process is as instructed in the S600.

[0050] Subsequently, photolithography can be performed on some repeating patterns and on the entire area. Then, healing (i.e., correction) (operation S700) can be performed on all patterns.

[0051] Here, the repair can check whether the pattern violates a mask rule check, for example, according to a predetermined criterion. Additionally or separately, a main repair can be performed to reduce an edge placement error (EPE), for example, according to any suitable technique. The repair is not limited thereto, and various types of repair can be performed.

[0052] Finally, mask tape-out (MTO) is performed (operation S800). For example, the MTO can instruct a final mask data, which has completed the OPC, to be transferred to a mask manufacturing team to request a mask to be manufactured. For example, a substrate for a mask can be exposed, for example, via an electron beam writing operation, based on the final mask data to form a mask. After the exposure process, the mask is manufactured by performing a series of processes, such as a development, etching, and cleaning process, on the exposed substrate.

[0053] The methods, processes, and / or operations (e.g., extraction, comparison of patterns) described herein can be performed by code or instructions to be executed by a computer, a processor, a controller, or other signal processing apparatus (e.g., via simulation to be implemented when a physical layer on a processing substrate). The computer, processor, controller, or other signal processing apparatus can be those described herein or apparatuses other than the elements described herein. Because the algorithms constituting the basis of the methods (or operations of the computer, processor, controller, or other signal processing apparatus) are described in detail, the code or instructions for implementing the operations of the method embodiments can convert the computer, processor, controller, or other signal processing apparatus into a dedicated processor for performing the methods described herein.

[0054] In addition, another embodiment can include a computer readable medium, such as a non-transitory computer readable medium, for storing the above-described code or instructions. The computer readable medium can be a volatile or non-volatile memory or other storage device, which can be removably or fixedly coupled to a computer, processor, controller, or other signal processing apparatus that is to execute the code or instructions for performing the methods described herein.

[0055] By summarizing and reviewing, in the mask manufacturing process, a desired circuit can be first designed, a layout of the circuit can be designed, and design data obtained through the OPC can be transferred as MTO design data. Subsequently, a mask data preparation (MDP) process can be performed based on the MTO design data, and a mask can be manufactured.

[0056] To secure high yield and characteristics of semiconductor devices, it is important to improve CD uniformity of a pattern formed on a wafer. A method of improving CD uniformity in a field by adjusting transmittance of a corresponding portion of a mask (i.e., a photomask) using CD data extracted from a wafer pattern has been used. Based on measured position information in a field obtained from a wafer and measured CD data, a laser can be used to adjust (e.g., correct) the transmittance for a specific area of a photomask. In this case, an approximate correction is performed by classifying data on a predetermined transmittance adjustment unit area. However, in this method for correcting the transmittance of a photomask, since the correction is concentratedly performed without considering various layouts present in all of the fields in the photomask, accurate correction cannot be made and its application is limited.

[0057] In contrast, aspects of the present disclosure provide an optical proximity correction method having improved operational efficiency. Aspects of the present disclosure also provide a method of manufacturing a mask including an optical proximity correction method having improved operational efficiency.

[0058] Example implementations have been disclosed and, although a particular terminology is employed, it is understood that the terms are used in a generic and descriptive sense only and not for purposes of limitation. In some instances, features, attributes and / or elements described in conjunction with a particular implementation are likewise applicable to other implementations, except where clearly incompatible therewith. Accordingly, it will be understood that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure as set forth in the following claims.

[0059] Korean Patent Application No. 10-2020-0047235, filed on April 20, 2020, in the Korean Intellectual Property Office and entitled "Optical Proximity Correction Method and Method of Manufacturing Mask Including the Same," is hereby incorporated by reference in its entirety.

Claims

1. An optical proximity correction method, comprising: providing a pattern mask formed with a plurality of first patterns; extracting at least one of the first patterns from the pattern mask; analyzing the extracted first pattern and reducing an area of the analyzed first pattern, performing a reverse lithography technique on the extracted and reduced first pattern to form a first first pattern; forming the first first pattern at a location where the first pattern is formed; and performing a correction on the pattern mask on which the first first pattern is formed, where performing the correction comprises determining whether a mask rule check is violated.

2. The optical proximity correction method of claim 1, wherein, The first patterns are identical patterns.

3. The optical proximity correction method of claim 2, wherein, Performing the lithography comprises performing the lithography on only one of the first patterns.

4. The optical proximity correction method of claim 1, wherein, Performing the correction comprises reducing an edge placement error (EPE).

5. An optical proximity correction method, comprising: providing a pattern mask formed with a plurality of first patterns and a plurality of second patterns; extracting at least one of the first patterns and at least one of the second patterns from the pattern mask; analyzing the extracted first and second patterns and reducing an area of the analyzed first and second patterns, respectively; performing a reverse lithography technique on the extracted and reduced first pattern to form a first first pattern; performing a reverse lithography technique on the extracted and reduced second pattern to form a second first pattern; forming the first first pattern at a location where the first pattern is formed; forming the second first pattern at a location where the second pattern is formed; performing a correction on the pattern mask on which the first first pattern and the second first pattern are formed, where performing the correction comprises determining whether a mask rule check is violated.

6. The optical proximity correction method of claim 5, wherein, The first patterns are identical patterns.

7. The optical proximity correction method of claim 6, wherein, Performing the lithography comprises performing the lithography on only one of the first patterns.

8. The optical proximity correction method of claim 5, wherein, The second patterns are identical patterns.

9. The optical proximity correction method of claim 8, wherein, Performing the lithography comprises performing the lithography on only one of the second patterns.

10. The optical proximity correction method of claim 5, wherein, The first patterns are different from the second patterns.

11. The optical proximity correction method of claim 5, wherein, Performing the correction comprises reducing an edge placement error (EPE).

12. A method of manufacturing a mask, the method comprising: manufacturing a pattern mask having a designed layout; extracting at least one first pattern from the pattern mask; analyzing the extracted first pattern and reducing an area of the analyzed first pattern; performing a reverse lithography technique on the extracted and reduced first pattern to form a first first pattern; forming the first first pattern at a location where the first pattern is formed; performing a correction on the pattern mask on which the first first pattern is formed to correct for optical proximity effects; and performing a mask tape-out (MTO) on the pattern mask on which the optical proximity effects have been corrected, where performing the correction comprises determining whether a mask rule check is violated.

13. The method of claim 12, wherein, The first patterns are identical patterns.

14. The method of claim 13, wherein, Performing the lithography comprises performing the lithography on only one of the first patterns.

15. The method of claim 12, wherein, Performing the correction comprises reducing an edge placement error (EPE).

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