Optical proximity correction method and mask manufacturing method by using the same

Abstract

The inventive concept provides an optical proximity correction (OPC) method capable of implementing a pattern having a critical pitch by using single exposure patterning, and a mask manufacturing method including the OPC method. The OPC method includes: receiving a design layout of a target pattern to be formed on a substrate; obtaining an OPC pattern by performing a first OPC on the design layout; obtaining a simulation contour of the OPC pattern; performing line end sharpening (LES) OPC on line ends of line patterns extending in the first direction and adjacent to each other in the first direction based on the simulated profile of the OPC pattern; cutting a portion of a line end of the line pattern; and performing a second OPC on a side line of another line pattern adjacent to the line end in a second direction perpendicular to the first direction and extending in the first direction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0082187 filed in the Korean Intellectual Property Office on June 26, 2023, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0003] The inventive concept relates to a method of manufacturing a mask, and more particularly, to an optical proximity correction (OPC) method and a method of manufacturing a mask using the OPC method. Background Art

[0004] In semiconductor processes, a photolithography process using a mask can be performed to form a pattern on a semiconductor substrate (such as a wafer). A mask can be simply defined as a pattern transfer body in which a pattern shape of an opaque material is formed on a transparent base material. The mask manufacturing process is briefly described. First, the desired circuit can be designed, and the layout of the circuit can be designed. The design data obtained by using the OPC method can then be transmitted as a mask tape-out (MTO) design data. Next, a mask data preparation (MDP) operation can be performed based on the MTO design data, and an exposure process, etc. can be performed on the mask substrate. Summary of the invention

[0005] The inventive concept provides an optical proximity correction (OPC) method capable of realizing a pattern having a critical pitch by using single-exposure patterning, and a mask manufacturing method including the OPC method.

[0006] In addition, problems to be solved by the technical ideas conceived by the present invention are not limited to those mentioned above, and a person of ordinary skill in the art can clearly understand other problems from the following description.

[0007] According to one aspect of the inventive concept, an optical proximity correction (OPC) method is provided, the method comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining an OPC pattern by performing a first OPC on the design layout; obtaining a simulated profile of the OPC pattern; based on the simulated profile, performing a line end sharpening (LES) OPC on line ends of a line pattern included in the OPC pattern, the line patterns extending in a first direction and adjacent to each other in the first direction; cutting a portion of at least one of the line ends of the line pattern; and performing a second OPC on a side line of another line pattern, the other line pattern being adjacent to at least one line end in a second direction perpendicular to the first direction and extending in the first direction.

[0008] In addition, according to another aspect of the present invention, an optical proximity correction (OPC) method is provided, the method comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining an OPC pattern by performing a first OPC on the design layout; obtaining a simulation profile of the OPC pattern; based on the simulation profile, defining a reference bridging margin area and a raised bridging margin area for line ends of a line pattern included in the OPC pattern, the line patterns extending in a first direction and adjacent to each other in the first direction; performing a line end sharpening (LES) OPC on at least one of the line ends so that an overlapping area where another line pattern adjacent to at least one line end in a second direction perpendicular to the first direction and extending in the first direction overlaps with the raised bridging margin area is removed; cutting a portion of at least one line end; and performing a second OPC on a side line of another line pattern, wherein, when the target pattern uses only the first OPC and includes a critical line width that would otherwise require two or more extreme ultraviolet (UEV) exposure processes, the target pattern is formed once using an EUV exposure process.

[0009] In addition, according to another aspect of the inventive concept, a mask manufacturing method is provided, the method comprising: performing an optical proximity correction (OPC) method to obtain an OPCed design layout, the OPCed design layout corresponding to a target pattern to be formed on a substrate; preparing mask tape-out (MTO) design data, the MTO design data being based on the OPCed design layout data; preparing mask data based on the MTO design data; and performing exposure on a mask substrate based on the mask data, wherein performing the OPC method comprises: receiving a design layout of a target pattern to be formed on a substrate, obtaining an OPC pattern by performing a first OPC on the design layout, obtaining a simulation profile of the OPC pattern, performing a line end sharpening (LES) OPC on line ends of a line pattern included in the OPC pattern based on the simulation profile, the line patterns extending in a first direction and being adjacent to each other in the first direction, cutting a portion of at least one of the line ends, and performing a second OPC on a side line of another line pattern, the other line pattern being adjacent to at least one line end in a second direction perpendicular to the first direction and extending in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a schematic flow chart of a process of an optical proximity correction (OPC) method according to at least one embodiment;

[0012] Figure 2 yes Figure 1 A detailed flow chart of performing line end sharpening (LES) OPC in the OPC method in FIG.

[0013] Figure 3 It is shown Figure 1 A conceptual diagram of a target pattern in a process of obtaining an OPC pattern and an OPC pattern as a first OPC result of an OPC method;

[0014] FIG. 4A to FIG. 4C It is used to explain the execution Figure 2 Conceptual diagram and scanning electron microscope (SEM) photographs of the process of defining the reference bridging margin area and the raised bridging margin area in the operation of LES OPC;

[0015] FIG. 5A to FIG. 5D It is used to explain the execution Figure 2 A conceptual diagram and SEM photograph of a process of thinning a portion of an OPC pattern corresponding to a line end in an operation of LES OPC;

[0016] Fig. 6A and Figure 6B is used to explain Figure 1 A conceptual diagram of processing of a portion of a cut wire end in an OPC method;

[0017] Fig. 7A and Figure 7B is used to explain Figure 1 A conceptual diagram of a process of performing a second OPC on a side line of a different line pattern in an OPC method;

[0018] FIG. 8A to FIG. 8C is a SEM photograph of a line pattern having a critical pitch, and a conceptual diagram for explaining single exposure patterning and double exposure patterning;

[0019] 9A to 9C are conceptual diagrams of a design layout of a target pattern, an OPC pattern of a comparative example by using the OPC method, and an OPC pattern of the present embodiment by using the OPC method, respectively; and

[0020] Fig.10 is a schematic flow chart of a mask manufacturing method including an OPC method according to at least one embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used for the same constituent elements, and repeated descriptions thereof are omitted.

[0022] Figure 1 is a schematic flow chart of a process of an optical proximity correction (OPC) method according to at least one embodiment, and Figure 2 yes Figure 1 Detailed flowchart of performing line end sharpening (LES) OPC in the OPC method in . Figures 3 to 7B It is used to explain Figure 1 Conceptual diagram and scanning electron microscope (SEM) photograph of the operation of the OPC method.

[0023] Reference Figure 1 In the OPC method of the present embodiment, a design layout of a target pattern to be formed on a substrate is received (S110). In this case, the target pattern represents a pattern to be formed on a substrate (e.g., a silicon (Si) substrate such as a wafer). For example, the target pattern may be a pattern to be formed on a substrate by transferring a pattern on a mask to the substrate using an exposure process. On the other hand, because the pattern on the mask is reduced, projected, and transferred to the wafer, the pattern on the mask may have a larger size than the target pattern on the substrate.

[0024] The design layout represents a layout of a pattern on a mask corresponding to a target pattern. Due to the characteristics of the exposure process, the target pattern on the wafer may have a shape different from the shape of the pattern on the actual mask used in the exposure process. However, in at least some embodiments, the shape of the initial design layout of the pattern on the mask may be substantially the same as the shape of the target pattern.

[0025] On the other hand, in the OPC method of the present embodiment, the target pattern may have a line & space shape. In the line & space shape of the target pattern, the edge may include only lines. Therefore, the design layout of the target pattern of the line & space shape may correspond to the rectangular design layout. For reference, in the OPC method of the present embodiment, the target pattern may correspond to, for example, a post-cleaning inspection target pattern.

[0026] After receiving the design layout, an OPC pattern is obtained by performing a first OPC on the design layout (S120). The first OPC may correspond to, for example, a baseline OPC. The baseline OPC may represent a conventional OPC for achieving patterning close to a target pattern on a substrate. For reference, OPC may represent a method in which an optical proximity effect (OPE) due to the influence between adjacent patterns is generated during an exposure process as the pattern becomes finer, and in order to overcome this problem, the occurrence of OPE is suppressed by correcting the layout of the pattern on the mask.

[0027] In the case of a target pattern of line & space shapes, an OPC pattern (reference Figure 3The OPC pattern OPC1 / OP in the first OPC may include a hammerhead shape and a jog shape. In the OPC pattern OPC1 / OP after the first OPC, the line end of the line pattern may have a hammerhead shape, and the side line of the line pattern may be divided into small segments to have a jog shape. For reference, a segment may be referred to as a fragment, and may represent a line of a straight line shape corresponding to the edge of the design layout, or data of the line. The edge of the design layout may be divided into multiple segments according to a specific division rule. The length of the segment, the division rule, etc. may be set by the user who performs the OPC method.

[0028] Figure 3 It is shown in Figure 1 A conceptual diagram of a target pattern in a line & space shape and an OPC pattern OPC1 / OP after the first OPC in a process of obtaining an OPC pattern in an OPC method. Figure 3 , the shaded portion may correspond to a target pattern TP of a line & space shape, or a design layout corresponding to the target pattern TP (hereinafter, "target pattern"). The target pattern TP may include, for example, four line patterns, and on the right side, two line ends of the line patterns adjacent to each other are shown in the y direction. On the other hand, the straight lines on the periphery surrounding the target pattern TP may correspond to segments of the OPC pattern OPC1 / OP. In addition, as described above, the segments may be arranged in a stepped shape on the side lines of the line pattern, and the segments may have a hammerhead shape at the line ends of the line pattern.

[0029] After obtaining the OPC pattern OPC1 / OP through the first OPC, a simulated profile of the OPC pattern OPC1 / OP is obtained (refer to Figure 4A S-Con in) (S130). For example, data of the OPC pattern OPC1 / OP may be input into the OPC model, and the profile may be extracted by using simulation. For reference, in the OPC model, various baseline data may be input as input data. In this case, the baseline data may include data of the OPC pattern OPC1 / OP. In addition, the baseline data may include information data of the thickness, refractive index, dielectric constant, etc. of the photoresist (PR), and data of a source map for a type of irradiation system. However, the baseline data is not limited thereto. As a result, in an exposure process using a mask, as a result product produced by simulation using the OPC model, the simulated profile S-Con may correspond to the shape of the target pattern TP formed on the wafer. Therefore, the purpose of the OPC method may be to make the simulated profile S-con as similar as possible to the shape of the target pattern TP.

[0030] After the simulated profile S-Con is obtained, line end sharpening (LES) OPC is performed at line ends of line patterns adjacent to each other based on the simulated profile S-Con ( S140 ).

[0031] FIG. 4A to FIG. 4C It is used to explain the execution Figure 2 Conceptual diagram and SEM photograph of the process of defining the reference bridging margin area and the raised bridging margin area in the operation of LES OPC, and FIG. 5A to FIG. 5D It is used to explain the execution Figure 2 Conceptual diagram and SEM photograph of the process of thinning the portion of the OPC pattern corresponding to the line end in the operation of LES OPC. Figure 2 and 4A to 5D , describes in detail the operations for executing LES OPC.

[0032] Reference Figure 2 and FIG. 4A to FIG. 4C , the operation (S140) of performing LES OPC may first define a reference bridging margin area A (S142) of the line end of the line pattern. The reference bridging margin area A may be defined based on a reference radius Ra. The reference radius Ra may correspond to 1 / 2 of the width of the line pattern in a first direction (e.g., the x direction). In addition, the reference bridging margin area A may be defined as an area covered by the reference radius Ra plus a process margin at the line end. In this case, the process margin may include a distance in the x direction between line patterns adjacent to each other in the x direction. For example, when the distance between the line patterns in the x direction is defined as α, the reference bridging margin area A may be defined in the form of a circle having a radius of Ra+α at the line end.

[0033] In addition, the line end radius R can be defined at the line end LE . Wire end radius R LE The reference radius Ra may be defined as the distance from the point where the side line of the line pattern extending in the second direction (e.g., the y direction) changes from a straight line to a curved shape to the line end of the line pattern in the y direction. When the simulated profile S-con is obtained as a semicircle at the line end, the reference radius Ra may be the same as the line end radius R LE The same, however the example is not limited thereto.

[0034] Next, a raised bridging margin area B of the line end of the line pattern may be defined (S144). The raised bridging margin area B may be defined based on a raised radius Rb or a raised LEB. The raised radius Rb may correspond to 1 / 2 of the maximum width of the raised LEB of the line end in the x-direction. Additionally, the raised bridging margin area B may be defined as an area covered by the raised LEB plus the process margin at the line end. For example, when the process margin is α, the raised bridging margin area B may be defined as a shape covered by the raised LEB plus α. Figure 4AIn the embodiment, since the ridge LEB forms a bulge at the semicircular portion with the ridge radius Rb in both directions of the x-direction, the ridge bridging margin area B can be defined as an ellipse that is longer in the x-direction. In addition, according to at least one embodiment, the ridge bridging margin area B can also be defined as an area covered by the ridge radius Rb plus the process margin. In this case, the ridge bridging margin area B can present a circular and / or annular shape.

[0035] The first overlap region OL-A1 may be generated by the uplift bridging margin region B. The first overlap region OL-A1 may refer to a region where a line pattern adjacent to the uplift bridging margin region B in the x direction overlaps the uplift bridging margin region B. When a width of the first overlap region OL-A1 in the x direction is defined as Dbul, Dbul may be calculated by using Equation 1 below.

[0036] [Equation 1]

[0037] Dbul=Rb-Ra

[0038] Both Ra and Rb may correspond to the reference radius and bulge radius defined above, respectively. The reason for calculating Dbul by using Equation 1 may be that, as referenced Figure 4A As understood, it is shown that the raised bridging margin area B is defined by combining Rb with α which is a process margin, and when a circle in which α is added to Ra contacts an adjacent line pattern, the width of the raised bridging margin area B overlapping the line pattern adjacent to the raised bridging margin area B in the x direction can be calculated as Rb-Ra.

[0039] For reference, in an etching process of a substrate, the bump LEB may mean a shape in which both ends of a line end of a line pattern protrude outward. Figure 4B The SEM image of FIG. 1 shows that a line end bulge LEB appears at the line end of the line pattern. The line end bulge LEB at the line end may cause, for example, Figure 4C As shown, a line bridge L / B defect between adjacent line patterns. In addition, the line end ridge LEB may cause a pinch-off (P / O) defect on another adjacent line pattern. For reference, since the line is generally formed of copper (Cu), the line bridge L / B may also be referred to as Cu bridge. In addition, although the cause of the pinch-off P / O defect of another adjacent line pattern at the line end is set aside, it can be easily understood that the line bridge L / B defect at the line end portion of the adjacent line pattern is caused by the first overlapping area OL-A1 between the ridge bridge margin area B and another adjacent line pattern.

[0040] Reference Figure 2 and FIG. 5A to FIG. 5DAfter defining the ridge bridging margin area B, the portion of the OPC pattern corresponding to the line end is thinned (S146). Figure 5A As shown, the OPC patterns LES-OPC / OP of the line ends in the line patterns adjacent to each other in the y direction may be formed to be thin and long. Two pairs of arrows facing each other at each line end may indicate the OPC pattern LES-OPC / OP ratio. Figure 3 The OPC pattern OPC1 / OP is fine.

[0041] When the OPC pattern LES-OPC / OP at the line end becomes thin and long, such as Figure 5B As shown, the line end radius Rsh of the simulated profile S-Con' can be increased accordingly. LE The line end radius Rsh after LES-OPC can be changed, and the line end radius Rsh can be larger than the line end radius R LE As a result, LES-OPC may correspond to a process of intentionally increasing the wire end radius, removing the hammer head of the OPC pattern of the wire end, and thinning the shape of the wire end. Figure 5C The SEM photograph in actually shows a thinner and longer shape of the wire end by the wire pattern using LES-OPC.

[0042] When using LES-OPC to LE When the wire end radius Rsh is changed, the shape of the ridge LEB' can be changed, and therefore, the ridge bridging margin area B' can be changed. Figure 5B As described above, the ridge bridging margin area B' may be defined based on the ridge LEB' or the ridge radius Rb'. For example, the ridge radius Rb' may correspond to 1 / 2 of the maximum width of the ridge LEB' at the line end in the x-direction. In addition, the ridge bridging margin area B' may be defined as the area covered by the ridge LEB' or the ridge radius Rb' plus the process margin at the line end. In addition, LES-OPC may be performed so that the ridge radius Rb' satisfies the following equation 2.

[0043] [Equation 2]

[0044] Rc≤Rb'≤Ra

[0045] In Equation 2, the ridge radius Rb' is less than or equal to the reference radius Ra. For example, when the ridge radius Rb' exceeds the reference radius Ra, the ridge bridging margin region B' may overlap with the line pattern adjacent thereto in the x direction. On the other hand, the radius Rc may correspond to the minimum radius at the line end so that the pinch-off P / O defect does not occur at the line end portion. Figure 4A and Figure 5BIn FIG. 1 , the radius Rc is not shown, and a circle C defined by the radius Rc at the line end is shown. Figure 5D The SEM image of shows the pinch-off P / O defect that occurs due to the ridge radius Rb' being formed smaller than the radius Rc.

[0046] In addition, since the OPC pattern LES-OPC / OP at the line end becomes thin and long at the line end, the ridge LEB' also becomes long in the y direction, and therefore, the ridge bridging margin area B' also increases in the y direction. Figure 5B As shown, the raised bridging margin regions B' at the line ends of the line patterns adjacent to each other in the y direction may overlap each other to generate the second overlap region OL-A2. Therefore, a process of preventing the generation of the second overlap region OL-A2 may be performed.

[0047] Fig. 6A and Figure 6B is used to explain Figure 1 A conceptual diagram of a process of cutting a portion of a wire end in an OPC method.

[0048] Reference Figure 1 , Fig. 6A ,as well as Figure 6B After LES OPC, the line end portion is cut (S150). In order to cut the line end portion, first, the distance S between adjacent line ends in the target pattern TP can be defined. LE , and the distance Scut between adjacent line ends in the target pattern TP' after cutting. Figure 5A and Fig. 6A The target patterns TP and TP' in FIG. 1 show the distance S LE In addition, Fig. 6A The distance Scut is shown on the target pattern TP' in FIG. LE and Scut can also be defined by the simulated profiles S-Con' and S-Con". For example, the distance S LE can be defined as the distance between adjacent line ends of the simulated contour, and the distance Scut can be defined as the distance between adjacent line ends of the simulated contour after cutting. Figure 5B and Figure 6B The simulated profiles S-Con' and S-Con" show the distance S LE In addition, Figure 6B The distance Scut is shown on the simulated profile S-Con”.

[0049] When the width to be cut at the line end of each of the adjacent line patterns is defined as the width Dcut, it can be calculated based on the distance S LE and Scut, the width Dcut is calculated by using Eq. 3.

[0050] [Equation 3]

[0051] Dcut=(Scut-S LE ) / 2

[0052] Reference Figure 5B It can be understood that the width Dcut corresponds to 1 / 2 of the width of the second overlapping area OL-A2. LE The difference between may correspond to the maximum width of the second overlapping area OL-A2 in the y direction. Therefore, the width to be cut at the line end of each of the adjacent line patterns may be 1 / 2 of the maximum width or the width Dcut. Therefore, Equation 3 may hold. As a result, the second overlapping area OL-A2 may be removed by removing the line end of each of the line patterns by the width Dcut. For example, the raised bridging margin area B" at the line ends of adjacent line patterns in the y direction may not overlap with each other.

[0053] In addition, the line end of the cutting line pattern may correspond to the shape of the target pattern that is finally changed.For example, the OPC method of this embodiment may modify the target pattern, through which the target pattern to be formed on the substrate is slightly changed.

[0054] Fig. 7A and Figure 7B is used to explain Figure 1 A conceptual diagram of a process of performing a second OPC on a side line of a different line pattern in an OPC method.

[0055] Reference Fig. 7A and Figure 7B , after cutting the portion of the line end, a second OPC OPC2 is performed on the side line of another line pattern adjacent to the line end (S160). As described above, a pinch-off P / O defect may occur in another line pattern adjacent to the line end in the x direction. In order to prevent the pinch-off P / O defect, it may be necessary to make the portion of the other line pattern where the pinch-off P / O defect occurs thicker. Therefore, in the OPC method of this embodiment, the second OPC OPC2 may be performed to move the side line of another line pattern adjacent to the line end in the x direction and thicken the corresponding portion of the other line pattern.

[0056] As reference Fig. 7A As can be understood from the arrows in FIG. 1 , in the OPC pattern OPC2 / OP obtained by using the second OPC OPC2, the OPC pattern OPC2 / OP adjacent to the line end can be moved toward the line end, and therefore, it can be recognized that the corresponding portion of another line pattern is becoming thicker. Figure 7BIt can be understood that, in the simulated profile based on the OPC pattern OPC2 / OP, it may be required that the simulated profile portion of the corresponding portion of another line pattern does not overlap with the simulated profile portion of the line end.

[0057] Therefore, when the width of the side line portion of another line pattern after the second OPC OPC2 in the x direction is defined as width Wopc, and the width of the side line portion of another line pattern before the second OPC OPC2 in the x direction is defined as width W LES In order to prevent pinch-off P / O defects, the increased width Dopc defined by Equation 4 may be increased and / or maximized.

[0058] [Equation 4]

[0059] Dopc=Wopc-W LES

[0060] In Equation 4, the increased width Dopc may correspond to the increased width of the side line of the other line pattern that has been increased by the second OPC OPC2. Therefore, in order to prevent the pinch-off P / O defect, the increased width Dopc as the increased width of the side line of the other line pattern may be increased and / or maximized. On the other hand, the increased width Dopc may vary according to the size of the segment in the segment division on the side line of the other line pattern. For example, when the size of the segment decreases, the increased width Dopc may increase.

[0061] The OPC method of the present embodiment may include: a process of LES OPC for thinning the OPC pattern of the line end portion of the line patterns adjacent to each other in the y direction; a process of cutting a portion of the line end of each of the line patterns; and a process of performing a second OPC OPC2 on another line pattern adjacent to the line end in the x direction. Therefore, the OPC method of the present embodiment can fully ensure the mass production margin of the target pattern. The OPC method of the present embodiment can provide such a method: compared with the conventional OPC (e.g., the first OPC), it fully ensures the pinch-off P / O margin and the line bridge L / B with respect to the target pattern with a critical spacing, and in addition, fully ensures the pinch-off P / O margin in another line pattern adjacent to the line end. As a result, the OPC method of the present embodiment can provide such a method: it realizes the target pattern with a critical spacing by using single exposure patterning, and specifically, realizes the target pattern with a critical spacing by using single exposure patterning in an extreme ultraviolet (EUV) process. On the other hand, as described above, the OPC method of the present embodiment may include a process of modifying the target pattern by using a process of cutting a portion of the line end of each of the line patterns.

[0062] For reference, in the case of a pattern with a critical spacing in an EUV process, due to the limitations of semiconductor processes, it may be difficult and / or impossible to ensure a mass production margin without defects (such as, pinch-off P / O and bridging). Therefore, for a pattern with a critical spacing in an EUV process, it is usually possible to ensure mass production margin and yield by applying a double exposure patterning process or a double patterning process. Based on the manufacturing process, the double patterning process may also be referred to as a lithography-etching-lithography-etching (LELE) process. In addition, in order to form a pattern with a critical spacing, in addition to double patterning, triple patterning or quadruple patterning may also be used. However, when using a double patterning process, since the number of masks and the number of exposure processes increase accordingly, the double patterning process may be disadvantageous in terms of cost and time. On the other hand, as described above, the OPC method of the present embodiment can provide a method for realizing a target pattern with a critical spacing by fully ensuring a pinch-off P / O margin, a bridging margin, etc. of a target pattern with a critical spacing, by using a single exposure patterning or a single patterning process. In addition, “the OPC method ensures a margin” may have substantially the same meaning as “the OPC method provides a method of manufacturing a mask capable of ensuring a margin”.

[0063] FIG. 8A to FIG. 8C is a SEM photograph of a line pattern with a critical pitch and a conceptual diagram for explaining single exposure patterning and double exposure patterning.

[0064] Reference FIG. 8A to FIG. 8C , Fig. 8A The SEM images in the figure show defects that occur in a single exposure patterning process using EUV for a line pattern with a critical pitch. The leftmost and second leftmost SEM images show defects of pinched P / O and Cu bridging in a line pattern extending in the y direction, respectively. In addition, the second rightmost and rightmost SEM images show defects of pinched P / O and Cu bridging in a line pattern extending in the x direction, respectively.

[0065] It can be identified that the pinch-off P / O defect occurs at the line end of the line pattern. It can be identified that the pinch-off P / O defect of the leftmost SEM photo occurs in the line pattern adjacent to the right side of the two line patterns adjacent to each other in the y direction, and the Cu bridging defect of the second leftmost SEM photo occurs in the line end of the lower line pattern of the two line patterns adjacent to each other in the y direction. It can be identified that the pinch-off P / O defect of the second rightmost SEM photo occurs in the line pattern adjacent to the upper side of the two line patterns adjacent to each other in the x direction, and the Cu bridging defect of the rightmost SEM photo occurs in the line end of the left line pattern of the two line patterns adjacent to each other in the x direction.

[0066] Figure 8Bshows a shape in which a line pattern having a critical pitch is formed by using a single exposure patterning process, and Figure 8C 1 shows a shape of a line pattern having a critical pitch formed by using a double exposure patterning process. In order to distinguish between a single exposure patterning process and a double exposure patterning process, Figure 8B The line patterns are shown in the same shading in Figure 8C , the line pattern is shown in two shades. For example, a single exposure patterning process may refer to a process in which the entire line pattern is formed in one mask and the entire line pattern is formed by using a single exposure process. On the other hand, a double exposure patterning process may refer to a process in which the line pattern is divided into two masks, an exposure process is performed on each mask, and the entire line pattern is formed by using a total of two exposure processes.

[0067] exist Figure 8B and Figure 8C In the example, squares are shown in some line patterns, and such squares may correspond to portions where defects occur. For example, in the case of a single exposure patterning process, a pinch-off P / O defect and / or a line bridge L / B defect may occur in the squares. On the other hand, although not completely excluded, in the case of a double exposure patterning process, defects may not occur in the squares.

[0068] 9A to 9C They are conceptual diagrams of a design layout of a target pattern, an OPC pattern by using the OPC method of a comparative example, and an OPC pattern by using the OPC method of the present embodiment, respectively.

[0069] Reference 9A to 9C ,exist Fig. 9A , a design layout of a target pattern TP in a line & space shape is shown. In particular, the target pattern TP including a line pattern extending in the y direction may correspond to a pattern formed on a substrate by using an EUV process.

[0070] In the OPC pattern conv-OPC / OP obtained by applying the OPC method of the comparative example to the design layout of the target pattern TP, as shown in FIG. Fig. 9B As shown, the line end of the line pattern may have a hammer head shape, and the side line of the line pattern may have a stepped shape formed by small segments. The OPC method of the comparative example may include, for example, a baseline OPC corresponding to the above-mentioned first OPC. For reference, in Fig. 9BIn the figure, for convenience, the side line of the line pattern is shown as a straight line shape rather than a stepped shape. When a single patterning process using EUV is performed on the OPC pattern conv-OPC / OP obtained by using the OPC method of the comparative example, a line bridge L / B defect or a pinch-off P / O defect may occur at the line ends of the line patterns adjacent to each other indicated by the dotted ellipse or in other line patterns at their line ends.

[0071] Alternatively, if Fig. 9C As shown, the OPC pattern pre-OPC / OP obtained by using the OPC method of the present embodiment may have a shape in which the line end portions of the line patterns adjacent to each other are thinned, and in addition, the width of the side surface line of the other line patterns adjacent to the line end portions is increased. Therefore, even when a single patterning process using EUV is performed on the OPC pattern pre-OPC / OP obtained by using the OPC method of the present embodiment, a line bridge L / B defect or a pinch-off P / O defect may be prevented (and / or mitigated) at the line ends of the line patterns adjacent to each other indicated by the dotted ellipse or in another line pattern at its line end.

[0072] Fig.10 is a schematic flow chart of a mask manufacturing method including an OPC method according to at least one embodiment. Figures 1 to 7B Give a description and briefly give or omit references Figures 1 to 9C Repeat description given.

[0073] Reference Fig.10 According to at least one embodiment, a mask manufacturing method including an OPC method (hereinafter, referred to as a "mask manufacturing method") may first perform an OPC method (S210). The OPC method in the operation of performing the OPC method (S210) may include Figure 1 OPC method. The OPC method may include receiving a design layout of a target pattern, obtaining an OPC pattern by performing a first OPC, obtaining a simulated contour, performing line end sharpening OPC LES-OPC on line ends of line patterns adjacent to each other, cutting portions of line ends of line patterns adjacent to each other, and performing a second OPC OPC2 on side lines of another line pattern. In addition, performing line end sharpening OPC LES-OPC may include defining a reference bridging margin area, defining a raised bridging margin area, and thinning an OPC pattern portion corresponding to a line end. Each operation of the OPC method may be the same as Figure 1 Each operation of the OPC method is the same as that of the OPC method of FIG. In addition, each operation included in the operation of performing line end sharpening OPC LES-OPC can be the same as that of Figure 2 The execution of line end sharpening OPC is the same as each operation included in the operation of LES-OPC.

[0074] After executing the OPC method, the mask tape-out (MTO) design data is transmitted to the mask manufacturing equipment and / or team (S220). Generally speaking, MTO can represent the task of transmitting the data of the final design layout obtained by using the OPC method and requesting the manufacture of the mask. Therefore, in the mask manufacturing method of the present embodiment, the MTO design data can ultimately represent the data of the OPCed (optical proximity corrected) design layout and / or the OPCed design layout obtained by using the OPC method. The MTO design data can have a graphic data format used in electronic design automation (EDA) software, etc. For example, the MTO design data can have a data format such as Graphic Data System II (GDS2) and Open Artwork System Exchange Standard (OASIS). In at least some embodiments, the design data may include instructions that enable the manufacture of the mask.

[0075] Next, mask data preparation (MDP) is performed (S230). MDP may include, for example, i) format conversion called fracturing; ii) addition of barcodes for mechanical reading, standard mask patterns for inspection, job decks, etc.; and iii) verification of automatic and manual methods. In this case, the job deck may mean an operation of generating a text file associated with a series of commands, such as arrangement information on a plurality of mask files, reference doses, exposure speeds, and exposure methods.

[0076] Format conversion (e.g., segmentation) may refer to a process of dividing the MTO design data into various regions and changing the MTO design data into a format for an electron beam writer. Segmentation may include, for example, data manipulation such as scaling, determining data size, rotating data, pattern reflection, and color inversion. In the conversion process by using segmentation, data of various systematic errors occurring somewhere in the process of transferring the design data to an image on a wafer may be corrected.

[0077] The data compensation process for the systematic error may be referred to as mask process correction (MPC), and may include, for example, line width adjustment referred to as critical dimension (CD) adjustment, an operation to increase pattern placement accuracy, etc. Therefore, segmentation may be a process that helps improve the quality of the final mask, and in addition, segmentation is a process performed in advance for MPC. In this case, the systematic error may be caused by distortion occurring in an exposure process, a mask development process, a mask etching process, a wafer imaging process, etc.

[0078] In at least some embodiments, the MDP may include an MPC. As described above, the MPC may be referred to as a process for correcting errors that occur during an exposure process (e.g., a process for correcting systematic errors). In these cases, the exposure process may include concepts that typically include electron beam writing, developing, etching, baking, and the like. In addition, data processing may be performed prior to the exposure process. The data processing may include a preprocessing process for mask data, and may include syntax checking of mask data, exposure time prediction, and the like.

[0079] After the mask data is prepared, the mask substrate is exposed based on the mask data (S240). In these cases, exposure can mean, for example, electron beam writing. In this case, electron beam writing can be performed by using, for example, a grayscale writing method using a multi-beam mask writer (MBMW). In addition, electron beam writing can also be performed by using a variable shape beam (VSB) writer.

[0080] On the other hand, after the MDP is completed, a process of converting the mask data into pixel data may be performed before the exposure process. The pixel data may include data directly used for actual exposure, and may include data on the shape of the object to be exposed and data on the dose assigned to each shape of the object. In this case, the data on the shape may include bitmap data that has been converted from shape data or vector data by rasterization, etc.

[0081] After the exposure process, a series of processes are performed to complete the mask (S250). The series of processes may include processes such as development, etching, cleaning, etc. In addition, a series of processes for manufacturing the mask may include a measurement process, a defect inspection process, and a defect repair process. In addition, a series of processes for manufacturing the mask may also include a thin film application process. In this case, when the absence of contamination particles or chemical stains is verified by the final cleaning and inspection process, the thin film application process may refer to a process of attaching a thin film to the surface of the mask to protect the mask from subsequent contamination during the transportation and service life of the mask.

[0082] In the mask manufacturing method conceived by the present invention, the OPC method may include: a LES OPC process for thinning the OPC pattern of the line end portion of the line patterns adjacent to each other in the y direction; a process of cutting a portion of the line end of each of the line patterns; and a process of performing a second OPC on another line pattern adjacent to the line end in the x direction. Therefore, the mask manufacturing method conceived by the present invention can ensure sufficient mass production margin for the target pattern with a critical pitch, so that a mask that realizes the target pattern with a critical pitch by using single exposure patterning can be manufactured. In particular, the mask manufacturing method conceived by the present invention can ensure the manufacture of an EUV mask, which is reliable and does not generate pinch-off P / O defects and line bridge L / B defects even when the target pattern with a critical pitch is realized in the EUV process by using single exposure patterning.

[0083] While the inventive concept has been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the appended claims.

Claims

1. An optical proximity correction method, comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining an optical proximity correction pattern by performing a first optical proximity correction on the design layout; obtaining a simulated profile of the optical proximity correction pattern; performing line end sharpening optical proximity correction on line ends of line patterns included in the optical proximity correction pattern, the line patterns extending in a first direction and adjacent to each other in the first direction, based on the simulated profile; cutting a portion of at least one of the line ends of the line patterns adjacent to each other; as well as A second optical proximity correction is performed on a side line of another line pattern that is adjacent to the at least one line end in a second direction perpendicular to the first direction and extends in the first direction.

2. The optical proximity correction method according to claim 1, wherein: Performing the line end sharpening optical proximity correction comprises: defining a reference bridging margin area for the at least one line end based on the simulated profile; Based on the line end protrusion caused by etching, defining a protrusion bridging margin region for the at least one line end; and Another portion of the optical proximity correction pattern corresponding to the at least one line end is thinned so that an overlapping area where the raised bridging margin area overlaps with the another line pattern is removed.

3. The optical proximity correction method according to claim 2, wherein: The width Dbul is calculated using Equation 1 below, [Equation 1] Dbul=Rb-Ra The width Dbul corresponds to the width of the overlapping area in the second direction, The radius Ra is a reference radius corresponding to 1 / 2 of the width of the line pattern in the second direction, The radius Rb is a ridge radius corresponding to 1 / 2 of the maximum width of the line end ridge in the second direction, The reference bridging margin area is an area covered by the radius Ra plus the process margin at the at least one line end, and The ridge bridging allowance area is the area covered by the line end ridge or the radius Rb plus the process allowance at the at least one line end.

4. The optical proximity correction method according to claim 3, wherein: The line end sharpening optical proximity correction is performed so that when the radius Rb is changed to a radius Rb′ by changing the line end ridge, the radius Rb′ satisfies the following equation 2, [Equation 2] Rc≤Rb'≤Ra, and The radius Rc is the minimum radius at the at least one wire end such that pinch-off does not occur at the wire end portion.

5. The optical proximity correction method according to claim 2, wherein: In the step of cutting a portion of the at least one wire end, The width Dcut satisfies the following equation 3, [Equation 3] Dcut=(Scut-S LE ) / 2, The width Dcut corresponds to the width of cutting the at least one line end, Distance S LE is the distance between line ends adjacent to each other after performing the line end sharpening optical proximity correction, and The distance Scut is the distance between the adjacent wire ends after cutting.

6. The optical proximity correction method according to claim 5, wherein: The width Dcut is a width that prevents the raised bridging margin regions of the adjacent line ends from overlapping each other.

7. The optical proximity correction method according to claim 1, wherein: performing the second optical proximity correction to maximize an increased width Dopc corresponding to an increased width of a side line portion of the another line pattern in the second direction, The increased width Dopc is calculated using the following equation 4, [Equation 4] Dopc=Wopc-W LES , The width Wopc is the width of the side line portion in the second direction after the second optical proximity correction, and Width W LES is the width of the side line portion in the second direction before the second optical proximity correction.

8. The optical proximity correction method according to claim 7, wherein: The increased width Dopc varies according to the size of the segment in the segment division on the side line of the another line pattern.

9. The optical proximity correction method according to claim 1, wherein: The first optical proximity correction is a baseline optical proximity correction, and The optical proximity correction pattern corresponding to the line pattern includes a hammer head end and a step-shaped side line.

10. The optical proximity correction method according to claim 1, wherein: When the target pattern uses only the first optical proximity correction and includes a critical line width that would otherwise require two or more EUV exposure processes, the target pattern is formed once using the EUV exposure process.

11. An optical proximity correction method, comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining an optical proximity correction pattern by performing a first optical proximity correction on the design layout; obtaining a simulated profile of the optical proximity correction pattern; defining, based on the simulated profile, a reference bridging margin region and a raised bridging margin region for line ends of a line pattern included in the optical proximity correction pattern, the line patterns extending in a first direction and adjacent to each other in the first direction; performing line end sharpening optical proximity correction on at least one of the line ends so that an overlap region where another line pattern adjacent to the at least one line end in a second direction perpendicular to the first direction and extending in the first direction overlaps the raised bridging margin region is removed; cutting a portion of the at least one wire end; and performing a second optical proximity correction on the side lines of the another line pattern, Wherein, when the target pattern uses only the first optical proximity correction and includes a critical line width that would otherwise require two or more EUV exposure processes, the target pattern is formed once using the EUV exposure process.

12. The optical proximity correction method according to claim 11, wherein: The width Dbul is calculated using Equation 1 below, [Equation 1] Dbul=Rb-Ra The width Dbul corresponds to the width of the overlapping area in the second direction, The radius Ra is a reference radius corresponding to 1 / 2 of the width of the line pattern in the second direction, The radius Rb is a ridge radius corresponding to 1 / 2 of the maximum width of the line end ridge in the second direction, The line end sharpening optical proximity correction is performed so that when the radius Rb is changed to a radius Rb′ by changing the line end ridge, the radius Rb′ satisfies the following equation 2, [Equation 2] Where Rc≤Rb'≤Ra, and The radius Rc is the minimum radius at the at least one wire end such that pinch-off does not occur at the wire end portion.

13. The optical proximity correction method according to claim 11, wherein: In the step of cutting a portion of the at least one wire end, The width Dcut satisfies the following equation 3, [Equation 3] Dcut=(Scut-S LE ) / 2, The width Dcut corresponds to the width of cutting the at least one line end, Distance S LE is the distance between line ends adjacent to each other after performing the line end sharpening optical proximity correction, The distance Scut is the distance between the adjacent wire ends after cutting, and The width Dcut is a width that prevents the raised bridging margin regions of the adjacent line ends from overlapping each other.

14. The optical proximity correction method according to claim 11, wherein: performing the second optical proximity correction to maximize an increased width Dopc corresponding to an increased width of a side line portion of the another line pattern in the second direction, The increased width Dopc is calculated using the following equation 4, [Equation 4] Dopc=Wopc-W LES , The width Wopc is the width of the side line portion in the second direction after the second optical proximity correction, and Width W LES is the width of the side line portion in the second direction before the second optical proximity correction.

15. A mask manufacturing method, comprising: performing an optical proximity correction method so that an optical proximity corrected design layout is obtained, the optical proximity corrected design layout corresponding to a target pattern to be formed on a substrate; preparing mask tape-out design data, the mask tape-out design data being based on the design layout data for optical proximity correction; preparing mask data based on the mask tape-out design data; as well as performing exposure on the mask substrate based on the mask data, Wherein, executing the optical proximity correction method comprises: receiving a design layout of a target pattern to be formed on a substrate, obtaining an optical proximity correction pattern by performing a first optical proximity correction on the design layout, obtaining a simulated profile of the optical proximity correction pattern, performing line end sharpening optical proximity correction on line ends of line patterns included in the optical proximity correction pattern, the line patterns extending in a first direction and adjacent to each other in the first direction, based on the simulated profile, cutting a portion of at least one of the wire ends, and A second optical proximity correction is performed on a side line of another line pattern that is adjacent to at least one line end in a second direction perpendicular to the first direction and extends in the first direction.

16. The method according to claim 15, wherein: Performing the line end sharpening optical proximity correction comprises: defining a reference bridging margin area for the at least one line end based on the simulated profile; Based on the line end protrusion caused by etching, defining a protrusion bridging margin region for the at least one line end; and Another portion of the optical proximity correction pattern corresponding to the at least one line end is thinned so that an overlapping area where the raised bridging margin area overlaps with the another line pattern is removed.

17. The method according to claim 16, wherein: The width Dbul is calculated using Equation 1 below, [Equation 1] Dbul=Rb-Ra The width Dbul corresponds to the width of the overlapping area in the second direction, The radius Ra is a reference radius corresponding to 1 / 2 of the width of the line pattern in the second direction, The radius Rb is a ridge radius corresponding to 1 / 2 of the maximum width of the line end ridge in the second direction, The line end sharpening optical proximity correction is performed so that when the radius Rb is changed to a radius Rb′ by changing the line end ridge, the radius Rb′ satisfies the following equation 2, [Equation 2] Rc≤Rb'≤Ra, and The radius Rc is the minimum radius at the at least one wire end such that pinch-off does not occur at the wire end portion.

18. The method according to claim 16, wherein: In the step of cutting a portion of the at least one wire end, The width Dcut satisfies the following equation 3, [Equation 3] Dcut=(Scut-S LE ) / 2, The width Dcut corresponds to the width of cutting the at least one line end, Distance S LE is the distance between line ends adjacent to each other after performing the line end sharpening optical proximity correction, The distance Scut is the distance between the adjacent wire ends after cutting, and The width Dcut is a width that prevents the raised bridging margin regions of the adjacent line ends from overlapping each other.

19. The method according to claim 15, wherein: performing the second optical proximity correction to maximize an increased width Dopc corresponding to an increased width of a side line portion of the another line pattern in the second direction, The increased width Dopc is calculated using the following equation 4, [Equation 4] Dopc=Wopc-W LES , The width Wopc is the width of the side line portion in the second direction after the second optical proximity correction, and Width W LES is the width of the side line portion in the second direction before the second optical proximity correction.

20. The method of claim 15, further comprising: manufacturing a mask to form the target pattern based on a result of the second optical proximity correction, Wherein, when the target pattern uses only the first optical proximity correction and includes a line width that would otherwise require two or more EUV exposure processes, the mask is manufactured once using the EUV exposure process.

Images