OPC method and mask manufacturing method using OPC method

Abstract

An optical proximity correction (OPC) method and a mask manufacturing method using the OPC method are provided. The OPC method includes: receiving a design layout of a target pattern to be formed on a substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; and obtaining a second OPC pattern by curving the first OPC pattern.

Description

Technical Field

[0001] The inventive concept relates to a mask manufacturing method, and more particularly, to an optical proximity correction (OPC) method and a mask manufacturing method using the OPC method. Background Art

[0002] In the semiconductor process, a photolithography process using a mask can be performed to form a pattern on a semiconductor substrate such as a wafer. Simply put, a mask can be said to be a pattern transfer material that forms a pattern shape of an opaque material on a transparent base material. In order to briefly explain the manufacturing process of the mask, first, the required circuit is designed, the layout of the circuit is designed, and then the design data obtained through OPC is converted into mask tape-out (MTO) design data. Thereafter, mask data preparation (MDP) 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

[0003] The inventive concept provides an optical proximity correction (OPC) method and a mask manufacturing method using the OPC method, which can realize a pattern having a critical pitch through single-exposure patterning.

[0004] Furthermore, objects to be achieved by the present inventive concept are not limited to the above-mentioned objects, and other objects may be clearly understood by those skilled in the art through the following description.

[0005] According to some aspects 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 a first OPC pattern by performing baseline OPC on the design layout; and obtaining a second OPC pattern by curving the first OPC pattern.

[0006] According to some aspects of the present invention, an OPC method is provided, the method comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; obtaining a second OPC pattern by curve-forming line ends of the first OPC pattern; obtaining a simulated profile of the second OPC pattern; and determining whether there is a defect in the simulated profile.

[0007] According to some aspects of the present invention, a mask manufacturing method is provided, the method comprising: executing an OPC method to obtain an OPC-processed design layout of a target pattern to be formed on a substrate; transferring data about the OPC-processed design layout as mask tape-out (MTO) design data; preparing mask data based on the MTO design data; and exposing a mask substrate based on the mask data, wherein executing the OPC method comprises: receiving a design layout of the target pattern to be formed on the substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; and obtaining a second OPC pattern by curving relative line ends of the first OPC pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present invention will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0009] Figure 1 is a flow chart schematically illustrating an optical proximity correction (OPC) method according to some embodiments;

[0010] Figure 2 is a conceptual diagram illustrating a target pattern in the form of lines and spaces and a first OPC pattern based on a baseline OPC result in an operation of obtaining a first OPC pattern according to some embodiments;

[0011] Figure 3 is a conceptual diagram illustrating a first OPC pattern and a second OPC pattern in an operation of obtaining a second OPC pattern according to some embodiments;

[0012] Figure 4 is a flow chart schematically illustrating an OPC method according to some embodiments;

[0013] Figure 5 is a flow chart schematically illustrating a method for performing line end curve forming according to some embodiments;

[0014] Figure 6 is a conceptual diagram illustrating a first OPC pattern and a second OPC pattern in an operation of obtaining a second OPC pattern according to some embodiments;

[0015] Fig. 7A and Figure 7B is a scanning electron microscope (SEM) picture showing defects of a line pattern with a critical pitch;

[0016] Figure 8 and Fig. 9 is a conceptual diagram for describing the concepts of single exposure patterning and double exposure patterning;

[0017] Fig. 10A , Fig. 10B , Fig. 10C and Fig. 10D is a design layout conceptual diagram of a target pattern, an OPC pattern according to an OPC method of a comparative example, and an OPC pattern according to an OPC method of the present embodiment; and

[0018] Fig.11 is a flow chart schematically illustrating a process of a mask manufacturing method using an OPC method according to some embodiments. DETAILED DESCRIPTION

[0019] Hereinafter, example embodiments are described in detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used for the same elements, and redundant descriptions thereof are omitted here.

[0020] Figure 1 is a flow chart schematically illustrating an optical proximity correction (OPC) method according to some embodiments.

[0021] refer to Figure 1 In the OPC method of the present embodiment, first, a design layout of a target pattern to be formed on a substrate may be received in operation S110. Here, the target pattern may refer to a pattern to be formed on a silicon (Si) substrate such as a wafer. In other words, the pattern on the mask may be transferred to the substrate through an exposure process to form the target pattern on the substrate. At the same time, the pattern on the mask may be scaled down and projected and transferred to the wafer, and the size of the pattern on the mask may be larger than the size of the target pattern on the substrate.

[0022] The design layout may refer to the layout of a pattern on a mask corresponding to a target pattern. Due to the nature of the exposure process, the shape of the target pattern on the wafer and the pattern on the actual mask used in the exposure process may be different from each other. However, 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.

[0023] Meanwhile, in the OPC method of the present embodiment, the target pattern may include a line and space form. The line and space form may make the edge consist of only straight lines. Therefore, the design layout of the target pattern in the line and space form may correspond to a right-angle design layout. For reference, in the OPC method of the present embodiment, the target pattern may be, for example, an afterclean inspection (ACI) target pattern.

[0024] After receiving the design layout, in operation S120, a first OPC pattern ( Figure 2Baseline OPC refers to the normal OPC used to achieve patterning that is closest to the target pattern on the substrate. Figure 2 The first OPC pattern ( Figure 2 in OPC / OP).

[0025] Figure 2 is a conceptual diagram illustrating a target pattern in the form of lines and spaces and a first OPC pattern based on a baseline OPC result in an operation of obtaining a first OPC pattern according to some embodiments.

[0026] refer to Figure 2 , the shaded portion may correspond to a target pattern TP in the form of lines and spaces or a design layout corresponding thereto (hereinafter, collectively referred to as a “target pattern”). The target pattern TP may include four line patterns, and Figure 2 The right hand side of shows the line ends of two adjacent line patterns in the second horizontal direction (Y direction). The two line ends may face each other. At the same time, the outer straight line surrounding the target pattern TP may correspond to the line segment of the first OPC pattern (OPC / OP).

[0027] In this specification, the direction parallel to the main surface of the substrate may be referred to as a horizontal direction (X direction and / or Y direction), and the direction perpendicular to the horizontal direction (X direction and / or Y direction) may be referred to as a vertical direction (Z direction).

[0028] If the target pattern is in the form of lines and spaces, the first OPC pattern (OPC / OP) is the result after the baseline OPC of the design layout, which may include a hammerhead shape and a jog shape. Specifically, in the first OPC pattern (OPC / OP) after the baseline 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 line segments to become a jog shape. For reference, a line segment may also be referred to as a fragment, and may refer to a line in a straight line shape corresponding to the edge of the design layout, or the data of the line. The edge of the design layout may be divided into multiple line segments according to a specific division rule. The user may set the length of the line segment or the division rule by executing the OPC method.

[0029] The baseline OPC may further include a design rule check (DRC) operation. The DRC operation may include an operation to determine whether the first OPC pattern (OPC / OP) complies with specified design rules.

[0030] For reference, the OPC method refers to a method of suppressing the optical proximity effect (OPE) by correcting the layout of the pattern to overcome the above-mentioned problem when the optical proximity effect (OPE) is generated due to the influence between adjacent patterns in the exposure process as the pattern is miniaturized. This OPC method can be roughly divided into two methods: one is a rule-based OPC method, and the other is a simulation-based or model-based OPC method. For example, the OPC method of the present embodiment can be a model-based OPC method. The model-based OPC method can have advantages in terms of time and cost because it only uses the measurement results of representative patterns without measuring all of a large number of test patterns.

[0031] Back to Figure 1 After the first OPC pattern (OPC / OP) is obtained through the baseline OPC, in operation S130, a second OPC pattern (OPC / OP) may be obtained by performing curve forming on the first OPC pattern (OPC / OP). Figure 3 CS-OPC / OP in ). Figure 3 The second OPC pattern is described in detail.

[0032] Figure 3 is a conceptual diagram illustrating a first OPC pattern and a second OPC pattern in an operation of obtaining a second OPC pattern according to some embodiments.

[0033] refer to Figure 3 ,For example, Figure 1 Operation S130 may include an operation of rounding (or curving) each first OPC pattern (OPC / OP). The second OPC pattern (CS-OPC / OP) obtained by curving the first OPC pattern (OPC / OP) may also be referred to as a curved shape (CS)-OPC pattern (CS-OPC / OP). Therefore, the CS-OPC pattern (CS-OPC / OP) may include a plurality of rounded corner patterns. In other words, the CS-OPC pattern (CS-OPC / OP) may include an edge having a curved shape. Therefore, the first OPC pattern (OPC / OP) may include a straight edge (i.e., a straight edge), and the second OPC pattern (CS-OPC / OP) may include a curved edge.

[0034] In the present specification, "bend", "curve", and "round" may have substantially the same meaning. In more detail, "curve" used herein with respect to a corner may mean that the corner is modified into a curved shape or a round shape.

[0035] As for the method of performing corner rounding on the first OPC pattern (OPC / OP), a curvature-based method can be used. The curvature-based corner rounding method can include: an operation of identifying the corner of the target pattern, an operation of generating the curvature of the identified corner, and an operation of modifying the target pattern with a reference curvature. In the curvature-based corner rounding method, a short line segment is formed along the edge of a shape with a large curvature, and a long line segment is generated along the edge of a shape with a small curvature. In more detail, for example, in the operation of generating the curvature of the identified corner, a Bezier curve algorithm can be used.

[0036] However, the method of performing corner rounding on the first OPC pattern (OPC / OP) is not limited to the above method. For example, corner rounding can be performed based on machine learning, or in some other embodiments, the first OPC pattern (OPC / OP) can be divided into multiple points, and corner rounding can be performed based on each point.

[0037] Back to Figure 1 , after obtaining the CS-OPC pattern (CS-OPC / OP), the simulated profile of the CS-OPC pattern (CS-OPC / OP) can be obtained in operation S140. That is, after obtaining the second OPC pattern (CS-OPC / OP), the simulated profile of the second OPC pattern (CS-OPC / OP) can be obtained in operation S140. For example, the profile can be extracted by inputting the data of the CS-OPC pattern (CS-OPC / OP) into the OPC model through simulation. For reference, in the OPC model, various basic data can be input as input data. Here, the basic data may include the data of the CS-OPC pattern (CS-OPC / OP). In addition, the basic data may also include: information data such as the thickness, refractive index, dielectric constant of the photoresist (photoresist, PR), and light source diagram data of the shape of the lighting system. However, the basic data is not limited to the above-mentioned example data. Ultimately, the simulated profile is the result obtained by simulating using the OPC model, and may correspond to the shape of the target pattern TP formed on the wafer in the exposure process using the mask. Therefore, making the simulated profile as similar as possible to the shape of the CS-OPC pattern (CS-OPC / OP) may correspond to the purpose of the OPC method.

[0038] According to some embodiments, before obtaining the simulated profile of the CS-OPC pattern (CS-OPC / OP), a DRC operation on the CS-OPC pattern (CS-OPC / OP) may be further included.

[0039] After the simulation is performed, it is determined in operation S150 whether there are defects in the simulation profile. Here, the defect may correspond to a case where the root mean square (RMS) of the critical dimension (CD) error is greater than a set reference value, a case where the electric potential energy (EPE) is greater than a set reference value, a case where a pinch-off (P / O) defect exists, a case where a bridge effect exists, etc. In addition, when there are other items in the simulation, the case where the corresponding item deviates from the reference value may also correspond to a defect. Meanwhile, according to some embodiments, the operation S150 of determining whether there are defects may be included in the operation S140 of obtaining the simulation profile.

[0040] When there is a defect (Yes), the process proceeds to operation S120 of obtaining a first OPC pattern (OPC / OP) through baseline OPC. Meanwhile, before operation S120 of obtaining a first OPC pattern (OPC / OP) through baseline OPC, the cause of the defect may be analyzed and reflected in the OPC model. For example, operation S155 of modifying the first OPC pattern (OPC / OP) may be included.

[0041] When there are no defects (no), in operation S160, the CS-OPC layout including the corresponding CS-OPC pattern (CS-OPC / OP) can be determined as the final OPC layout. That is, when there are no defects (no), in operation S160, the CS-OPC layout including the corresponding second OPC pattern (CS-OPC / OP) can be determined as the final OPC layout. The final OPC layout can correspond to the design data of the mask. Thereafter, the final OPC layout can be transferred to the mask production group as mask tape-out (MTO) design data for mask production. For example, the final OPC layout can refer to the final layout that has been optically adjacently corrected (OPC) based on the OPC method of the present embodiment.

[0042] The OPC method of the present embodiment may include a CS-OPC process for curving the OPC pattern. Therefore, the OPC method of the present embodiment can ensure that the target pattern has sufficient production margin. Specifically, compared with ordinary OPC (e.g., baseline OPC method), the OPC method of the present embodiment can ensure that the target pattern with a critical pitch has sufficient P / O margin and line bridge L / B margin, and can also ensure that other line patterns adjacent to the line end have sufficient P / O margin. As a result, the OPC method of the present embodiment makes it possible to realize a target pattern with a critical pitch by single exposure patterning, and in particular, makes it possible to realize a target pattern with a critical pitch by single exposure patterning in an extreme ultraviolet (EUV) process.

[0043] For reference, in the case where the pattern has a critical pitch in the EUV process, due to the limitation of the semiconductor process, it may not be possible to ensure that there are no defects such as P / O and bridging during mass production. Therefore, in the EUV process, a double exposure patterning process or a double patterning process can generally be applied to a pattern with a critical pitch to ensure large-scale production margin and yield. The double patterning process can also be referred to as a lithography-etching-lithography-etching (LELE) process based on the process. In addition, in order to form a pattern with a critical pitch, a triple patterning and / or quadruple patterning other than double patterning can also be used to form a pattern with a critical pitch. However, when using the double patterning process, the number of masks and exposure processes increases accordingly, which may be very disadvantageous in terms of cost and time. On the other hand, as described above, the OPC method of the present embodiment can ensure sufficient large-scale production margin (such as P / O margin and bridging margin) and the yield of the target pattern with a critical pitch, so that the target pattern with a critical pitch can be achieved by a single exposure patterning or a single patterning process. Furthermore, when the OPC method ensures a margin, it may mean substantially the same meaning as that the OPC method produces a mask capable of ensuring a margin.

[0044] Figure 4 is a flow chart schematically illustrating an OPC method according to some embodiments. Figures 1 to 3 as well as Figure 4 The OPC method of this embodiment is Figure 1 The difference between the OPC method of the present embodiment is that, in the OPC method of the present embodiment, only the first OPC pattern (for example, Figure 6 The OPC / OP in the Figure 1 In the OPC method of the present invention, the first OPC pattern (for example, Figure 3 Curveization is performed on the entire area of ​​OPC / OP in.

[0045] refer to Figure 4 First, a design layout of a target pattern to be formed on a substrate is received in operation S210. Thereafter, a first OPC pattern (OPC / OP) may be obtained by performing a baseline OPC on the design layout in operation S220. Figure 4 Operations S210 and S220 in Figure 1 Operations S110 and S120 in FIG. 1 are substantially the same, and thus detailed descriptions thereof are omitted.

[0046] Thereafter, in operation S230, a second OPC pattern (OPC / OP) may be obtained by performing line end only curvature (LEOCS) on the first OPC pattern (OPC / OP). Figure 6LEOCS-OPC / OP in). For example, operation S230 may include an operation of performing line end corner rounding (or curving) on ​​each first OPC pattern (OPC / OP). The second OPC pattern (LEOCS-OPC / OP) obtained by performing line end corner rounding on the first OPC pattern (OPC / OP) may also be referred to as a LEOCS-OPC pattern (LEOCS-OPC / OP). Therefore, the LEOCS-OPC pattern (LEOCS-OPC / OP) may include a plurality of patterns whose line ends are rounded. Therefore, the first OPC pattern (OPC / OP) may include a straight edge (i.e., a straight edge), and the second OPC pattern (LEOCS-OPC / OP) may include a straight edge (i.e., a straight edge) and a curved edge. Reference Figure 5 and Figure 6 A method for performing line end curvature is described in detail.

[0047] Figure 5 is a flow chart schematically illustrating a method of performing line end curving according to some embodiments. Figure 6 is a conceptual diagram illustrating a first OPC pattern and a second OPC pattern in an operation of obtaining a second OPC pattern according to some embodiments.

[0048] refer to Figure 5 and Figure 6 In the method of performing line end curvature, first, in operation S231, a first DRC is performed on the obtained first OPC pattern (OPC / OP). The first DRC operation may include an operation of determining whether the first OPC pattern (OPC / OP) complies with a specified design rule.

[0049] For example, in the first DRC operation, the edge and angle of each first OPC pattern (OPC / OP) may be determined. For example, in the first DRC operation, the size and / or relative position of each first OPC pattern (OPC / OP) may be determined. For example, the first DRC operation may include an operation of separating each first OPC pattern (OPC / OP) into a plurality of polygons and an operation of modifying the positions of the plurality of polygons. Operation S231 may be performed so that operation S232 of identifying line ends may be performed later.

[0050] Thereafter, the line end may be identified in operation S232. The line end may be identified by the length of each first OPC pattern (OPC / OP) spaced apart in the horizontal direction (X direction and / or Y direction). For example, the line end of the first DRC operation may be identified based on the edge, angle, size, and / or relative position of each first OPC pattern (OPC / OP) determined in the first DRC operation.

[0051] exist Figure 6For example, the first OPC pattern (OPC / OP) includes four line patterns, and Figure 6 The right-hand side of shows the line ends of two lines adjacent to each other in the second horizontal direction (Y direction). In other words, Figure 6 Two line ends spaced apart from each other and facing each other in the second horizontal direction (Y direction) are shown. However, the shape and arrangement of the first OPC pattern (OPC / OP) may be modified differently. In other words, the shape and arrangement of the target pattern TP may be modified differently.

[0052] exist Figure 6 In the embodiment, two line patterns spaced apart from each other in the second horizontal direction (Y direction) may be spaced apart from each other by a first distance S 1 In addition, a portion of each of the two line patterns located at the bottom may be spaced apart from an adjacent line pattern by a second distance S in the first horizontal direction (X direction). 2 .

[0053] In other words, the first distance S spaced in a direction parallel to the extending direction of each line pattern may be 1 and a second distance S spaced apart in a horizontal direction (X direction and / or Y direction) different from the above direction. 2 To determine the line end. For example, the first distance S 1 and the second distance S 2 To identify a line end (eg, included in one of the two line patterns), the first distance S 1 It may be the distance between a line end and an adjacent line end (for example, included in the other of the two line patterns) in a second horizontal direction (Y direction) parallel to the extending direction of the first OPC pattern (OPC / OP), and the second distance S 2 It may be the distance between the line end and the adjacent line pattern in the first horizontal direction (X direction) which is different from the second horizontal direction (Y direction).

[0054] In some other embodiments, line ends may be determined based on a gradient-based method (e.g., Sobel, Roberts, and / or Canny methods). Alternatively, line ends may be determined based on a convolution-based method, a machine learning-based method, and / or a rule-based method. Various modifications may be made to the method of identifying line ends.

[0055] Thereafter, the line ends may be separated in operation S233. Figure 4 In the OPC method of , only the line ends may be curved, and thus the operation of separating the line ends may be included. Figure 6, as an example, a line end separated by a square with a dashed outline is shown. As used herein, a line pattern including a line end may be referred to as a separation line pattern after the line end is separated. In other words, a line pattern including a line end may include a separation line end and a separation line pattern.

[0056] The separation line end may include: a first portion LE1 coupled to (or connected to) the separation line pattern afterwards (and / or before), and a second portion LE2 facing a different line end. The first portion LE1 and the second portion LE2 may be spaced apart from each other in the extension direction of the line pattern. Figure 6 In the embodiment, since the line pattern extends in the second horizontal direction (Y direction), the first portion LE1 and the second portion LE2 may be spaced apart from each other in the second horizontal direction (Y direction). Figure 6 In the embodiment, the first portion LE1 and the second portion LE2 may be adjacent to each other in the second horizontal direction (Y direction).

[0057] Thereafter, in operation S234, the line end may be chamfered. For example, the second portion LE2 of the line end may be chamfered. As a method for chamfering the line end of the first OPC pattern (OPC / OP), the method described above with reference to FIG. Figure 3 The curvature-based method described. The curvature-based corner rounding method may include an operation of identifying a corner of a target pattern, an operation of generating a curvature of the identified corner, and an operation of modifying the target pattern with a reference curvature. In the curvature-based corner rounding method, a short line segment is formed along an edge of a shape with a large curvature, and a long line segment is generated along an edge of a shape with a small curvature. In more detail, for example, in the operation of generating the curvature of the identified corner, a Bezier curve algorithm may be used.

[0058] However, the method of performing corner rounding on the line end of the first OPC pattern (OPC / OP) is not limited to the above method. For example, the line end of the first OPC pattern (OPC / OP) can be rounded based on machine learning, or in some other embodiments, the line end of the first OPC pattern (OPC / OP) can be divided into multiple points, so that the corner rounding can be performed based on each point.

[0059] In some embodiments, the first distance S 1 (ie, the separation distance between adjacent line ends in the first OPC pattern (OPC / OP)) may be equal to the first distance S 1 ' (ie, the separation distance between adjacent line ends in the second OPC pattern (LEOCS-OPC / OP)). In some other embodiments, the first distance S 1 (ie, the separation distance between adjacent line ends in the first OPC pattern (OPC / OP)) may be greater than the first distance S 1'(ie, the separation distance between adjacent line ends in the second OPC pattern (LEOCS-OPC / OP)).

[0060] In addition, with the second distance S 2 (i.e., the distance between the line end in the first OPC pattern (OPC / OP) and the adjacent line pattern) is compared to the second distance S 2 ' (ie, the distance between the line end in the second OPC pattern (LEOCS-OPC / OP) and the adjacent line pattern) can be increased. For example, the second distance S 2 ' can be greater than the second distance S 2 When the second distance S in the first OPC pattern (OPC / OP) 2 Compared to the second distance S in the second OPC pattern (LEOCS-OPC / OP) 2 ' increases, the possibility of bridging defects can be reduced. In some other embodiments, the second distance S 2 ' can be equal to the second distance S 2 .

[0061] For example, the height H of the curved line end (eg, the line end after corner rounding) may be less than half of the line pattern width W. The height H of the curved line end may represent the height H of the curved line end in a direction parallel to the extension direction of the line pattern (eg, Figure 6 In the second horizontal direction (Y direction) of the line pattern, the distance from the line end to the end point of the curved edge. In addition, the width W of the line pattern can be substantially equal to the width of the line end. In other words, the height H of the curved line end can be less than or equal to half of the width of the curved line end. For example, when the width W of the line pattern is about 20 nanometers or less, the height H of the curved line end can be about 10 nanometers or less. Figure 6 , the width W of the line pattern (and the width of the bending line end) may be measured in the first horizontal direction (X direction).

[0062] Thereafter, in operation S235, a second DRC may be performed on the LEOCS-OPC pattern (LEOCS-OPC / OP). That is, in operation S235, a second DRC may be performed on the second OPC pattern (LEOCS-OPC / OP). The second DRC may determine whether the line end rounding process is appropriate.

[0063] Thereafter, in operation S236, the rounded line end and the line pattern may be coupled to each other. In other words, the first portion ( Figure 6 LE1 in ) can be connected to the dividing line pattern. Therefore, the fillet processing can be performed only on the line end.

[0064] Back to Figure 4Thereafter, operation S240 of obtaining a simulated profile of the second OPC pattern (LEOCS-OPC / OP) and operation S250 of determining whether a defect exists in the simulated profile may be performed.

[0065] Figure 4 Operations S240 and S250 in Figure 1 Operations S140 and S150 in FIG. 1 are substantially the same except that the input data is a LEOCS-OPC pattern (LEOCS-OPC / OP) instead of a CS-OPC pattern (CS-OPC / OP), and thus a detailed description thereof is omitted.

[0066] When there is a defect (Yes), the process proceeds to operation S220 of obtaining a first OPC pattern (OPC / OP) by baseline OPC. Meanwhile, before operation S220 of obtaining a first OPC pattern (OPC / OP) by baseline OPC, the cause of the defect may be analyzed and reflected in the OPC model. For example, operation S255 of modifying the first OPC pattern (OPC / OP) may be included.

[0067] When there is no defect (No), in operation S260, the LEOCS-OPC layout including the corresponding LEOCS-OPC pattern (LEOCS-OPC / OP) may be determined as the final OPC layout. That is, when there is no defect (No), in operation S260, the LEOCS-OPC layout including the corresponding second OPC pattern (LEOCS-OPC / OP) may be determined as the final OPC layout. The final OPC layout may correspond to the design data of the mask. Thereafter, the final OPC layout may be transferred to the mask production group as MTO design data for mask production.

[0068] The OPC method of the present embodiment may include a LEOCS process for bending line end portions of line patterns adjacent to each other. In order to selectively bend only the line end portions, the OPC method of the present embodiment may include a process of separating the line ends.

[0069] Therefore, the OPC method of the present embodiment can ensure that the target pattern has sufficient production margin. Specifically, compared with ordinary OPC (e.g., baseline OPC method), the OPC method of the present embodiment can ensure that the target pattern with a critical pitch has sufficient P / O margin and line bridge L / B margin, and can also ensure that other line patterns adjacent to the line end have sufficient P / O margin. As a result, the OPC method of the present embodiment can realize a target pattern with a critical pitch by single exposure patterning, and in particular, can realize a target pattern with a critical pitch by single exposure patterning in an extreme ultraviolet (EUV) process. At the same time, as described above, the OPC method of the present embodiment may include a process for deforming the target pattern by a process for curving each line end of the line pattern. That is, the OPC method of the present embodiment may include a process for deforming the target pattern by a process for curving the relative line ends of each line pattern.

[0070] For reference, in the case where the pattern has a critical pitch in the EUV process, due to the limitation of the semiconductor process, it may not be ensured that there are no defects such as P / O and bridging during mass production. Therefore, in the EUV process, the double exposure patterning process or the double patterning process can be generally applied to the pattern with the critical pitch to ensure the margin and yield of mass production. The double patterning process can also be referred to as the LELE process based on the process. In addition, in order to form a pattern with a critical pitch, triple patterning and / or quadruple patterning other than double patterning can also be used to form a pattern with a critical pitch. However, when the double patterning process is used, the number of masks and exposure processes increases accordingly, which may be very disadvantageous in terms of cost and time. On the other hand, as described above, the OPC method of the present embodiment can ensure sufficient mass production margin (such as P / O margin and bridging margin) and the yield of the target pattern with a critical pitch, so that the target pattern with a critical pitch can be achieved by single exposure patterning or single patterning process. In addition, when the OPC method ensures the margin, it can mean that the mask that can ensure the margin is substantially the same as the OPC method.

[0071] Fig. 7A and Figure 7B is a scanning electron microscope (SEM) picture showing defects of a line pattern with a critical pitch. Fig. 7A is a SEM photo of a P / O defect, and Figure 7B This is a SEM image of a bridging defect. Fig. 7A and Figure 7B The SEM image shows defects caused by EUV in a line pattern with a critical pitch in a single exposure patterning process.

[0072] refer to Fig. 7A , P / O defects may occur at the line end. Fig. 7A , a P / O defect is shown to be formed inside a circle. A P / O defect may mean that a plurality of line patterns that should be connected to each other are spaced apart from each other. In other words, when a P / O defect occurs, a plurality of line patterns that should be connected to each other may be disconnected. A P / O defect may cause an electrical signal to be disconnected and / or reduce the yield of a semiconductor device.

[0073] refer to Figure 7B , bridging defects may occur at the line ends of the line pattern. Figure 7B , a bridging defect is shown to be formed inside a rectangle. For example, a bridging defect may occur between line ends or between line ends and line patterns. A bridging defect may mean that a plurality of line patterns that should be spaced apart from each other are connected to each other. A bridging defect may cause electrical signal short circuits, electrical signal interference, and / or reduced semiconductor device yield.

[0074] Figure 8 and Fig. 9 is a conceptual diagram for describing the concepts of single exposure patterning and double exposure patterning. Figure 8 shows a line pattern with a critical pitch formed by a single exposure patterning process, Fig. 9 A line pattern with a critical pitch formed by a double exposure patterning process is shown. Figures 1 to 7B as well as Figure 8 and Fig. 9 Give a description.

[0075] In order to distinguish between the single exposure patterning process and the double exposure patterning process, Figure 8 The same hatching is used to represent the line pattern in Fig. 9 Different hatching is used to indicate line patterns.

[0076] refer to Figure 8 and Fig. 9 , a single exposure patterning process may refer to a process in which all line patterns are formed within one mask and by one exposure process. On the other hand, a double exposure patterning process may refer to a process in which a line pattern is formed by dividing a pattern into two masks and performing one exposure process on each mask to form all line patterns by a total of two exposure processes.

[0077] Meanwhile, rectangles are shown in some line patterns, and these rectangles may correspond to portions where defects occur. For example, in a single exposure patterning process, P / O defects and / or bridge defects may occur in the rectangles. Meanwhile, although not completely excluded, in the case of a double exposure patterning process, defects may not occur in the rectangles.

[0078] Fig. 10A , Fig. 10B , Fig. 10C and Fig. 10D : is a design layout conceptual diagram of a target pattern, an OPC pattern according to an OPC method of a comparative example, and an OPC pattern according to an OPC method of this embodiment. In particular, Fig. 10C Based on reference Figures 1 to 3 A conceptual diagram of an OPC pattern of an OPC method described, and Fig. 10D Based on reference Figures 4 to 6 Conceptual diagram of an OPC pattern for describing an OPC method.

[0079] refer to FIG. 10A to FIG. 10D , Fig. 10A A design layout of a target pattern TP in the form of lines and spaces is shown. In particular, the target pattern TP including a line pattern extending in the second horizontal direction (Y direction) may correspond to a pattern formed on a substrate by an EUV process.

[0080] like Fig. 10B As shown, 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, the line end of the line pattern may have a hammer head shape, and the side line of the line pattern may have a step shape due to the small line segment. The OPC method of the comparative example may include a normal OPC, for example, the baseline OPC as described above (for example, reference Figure 1 and Figure 2 ). For reference, Fig. 10B In FIG. 1 , for convenience, the side lines of the line pattern are shown as straight lines instead of cut steps. When the single patterning process of EUV is performed on the OPC pattern (conv-OPC / OP) by the OPC method of the comparative example, Fig. 10B Wiring bridge defects and / or P / O defects may occur in line ends of adjacent line patterns indicated by dotted ovals in FIG. 1 and other line patterns adjacent to the line ends.

[0081] On the other hand, as mentioned above Figures 1 to 3 As described above, the OPC pattern (pre1-OPC / OP) obtained by applying the OPC method according to some embodiments may have a rounded shape, such as Fig. 10C In addition, as mentioned above Figures 4 to 6 As described above, the OPC pattern (pre2-OPC / OP) obtained by applying the OPC method according to some embodiments may have a shape of a bent line end (eg, bent opposite line ends), such as Fig. 10D Therefore, when a single patterning process by EUV is performed on the OPC patterns (pre1-OPC / OP and pre2-OPC / OP) by the OPC method according to some embodiments, Fig. 10C and Fig. 10DNo wiring bridge defect and P / O defect will occur in the line end of the adjacent line pattern indicated by the dotted oval in FIG. 1 and other line patterns adjacent to the line end.

[0082] According to some embodiments, even if a single patterning process of EUV is performed on the OPC pattern (pre1-OPC / OP and pre2-OPC / OP) by the OPC method, the distance between each line end and the adjacent pattern may be different from each other. Generally, when a single patterning process of EUV is performed, the distance between each line end and the adjacent pattern may be equal to each other. However, according to some embodiments, the OPC pattern (pre1-OPC / OP and pre2-OPC / OP) by the OPC method includes a corner rounding operation, and the distance between each line end and the adjacent pattern may also be different from each other. In some embodiments, as Fig. 10C and Fig. 10D As shown, at least two corresponding separation distances among a plurality of corresponding separation distances between opposite line ends of the OPC pattern (pre1-OPC / OP and / or pre2-OPC / OP) may be different from each other.

[0083] Fig.11 is a flow chart schematically illustrating a process of a mask manufacturing method including an OPC method according to some embodiments. Figures 1 to 6 as well as Fig.11 The above references will be briefly described or omitted. Figures 1 to 10D Description of the process.

[0084] refer to Fig.11 In a mask manufacturing method including an OPC method according to some embodiments (hereinafter referred to as “mask manufacturing method”), first, the OPC method may be performed in operation S10. Performing the OPC method in operation S10 may include performing Figure 1 OPC methods and / or Figure 4 Specifically, Figure 1 The OPC method may include an operation of receiving a design layout of a target pattern, an operation of obtaining a first OPC pattern (OPC / OP) by performing a baseline OPC, an operation of obtaining a second OPC pattern (CS-OPC / OP) by rounding the corners of the first OPC pattern, and an operation of obtaining a simulated profile of the second OPC pattern (CS-OPC / OP). In addition, Figure 4The OPC method may include an operation of receiving a design layout of a target pattern, an operation of obtaining a first OPC pattern (OPC / OP) by performing a baseline OPC, an operation of performing a first DRC on the first OPC pattern (OPC / OP), an operation of obtaining a second OPC pattern (LEOCS-OPC / OP) by rounding the line ends of the first OPC pattern, an operation of performing a second DRC on the second OPC pattern (LEOCS-OPC / OP), and an operation of obtaining a simulated profile of the second OPC pattern (LEOCS-OPC / OP). Figure 1 and Figure 4 Each operation of the OPC method is described in Each operation of the OPC method.

[0085] After performing the OPC method, in operation S20, the MTO design data may be transferred to the mask production group. Generally, MTO may refer to handing over the data on the final design layout obtained by the OPC method to the mask production group to request the production of the mask. Therefore, according to some embodiments, in the mask manufacturing method, the MTO design data may ultimately represent the OPC-processed design layout obtained by the OPC method or data related thereto. Such MTO design data may have a graphic data format used in electronic design automation (EDA) software, etc. For example, the MTO design data may have a data format such as Graphic Data System II (GDS2) and Open Graphics System Exchange Standard (OASIS).

[0086] Thereafter, mask data preparation (MDP) may be performed in operation S30. For example, MDP may include: i) format conversion called fracturing, ii) extended data such as a barcode for mechanical reading, a standard mask pattern for inspection, a job deck, and iii) verification of an automatic method and a manual method. Here, the job deck may refer to a text file that creates a series of instructions related to arrangement information of a multi-mask file, a reference dose, and an exposure speed or scheme, etc.

[0087] Format conversion (i.e., splitting) may refer to the process of dividing the MTO design data into each region and changing each region into the format of the electron beam exposure machine. For example, splitting may include data operations such as scaling, data resizing, data rotation, pattern reflection, color inversion, etc. When converting by splitting, data associated with many systematic errors that may occur somewhere during the conversion from the design data to the image on the wafer may be corrected.

[0088] The data correction process for systematic errors is called mask process correction (MPC), and can include, for example, line width adjustment, which is called CD adjustment, and operations for improving pattern arrangement accuracy, etc. Therefore, splitting can help improve the quality of the final mask and can also be a process for performing MPC in advance. Here, systematic errors may be caused by distortions that occur in the exposure process, mask development and etching process, wafer imaging process, etc.

[0089] Meanwhile, the MDP may include an MPC. As described above, the MPC may indicate a process for correcting errors (e.g., systematic errors) occurring during an exposure process. Here, the exposure process may be an overall concept including electron beam writing, developing, etching, baking, and the like. In addition, data processing may be performed before the exposure process. Data processing is a preprocessing process for a type of mask data, and may include syntax checking of mask data, exposure time prediction, and the like.

[0090] After the MDP, in operation S40, the mask substrate is exposed based on the mask data. Here, the exposure may indicate, for example, electron beam writing. Here, the electron beam writing may be performed according to, for example, a grayscale writing scheme using a multi-beam mask writer (MBMW). In addition, the electron beam writing may also be performed by using a variable shape beam (VSB) exposer.

[0091] Meanwhile, after the MDP operation, a process of converting mask data into pixel data may be performed before the exposure process (e.g., before exposing the substrate). Pixel data is data directly used for real exposure, and may include data on the shape to be exposed and data on the dose assigned to each shape. Here, the data on the shape may be bitmap data obtained by converting shape data (e.g., vector data) through rasterization or the like.

[0092] After exposing the substrate, in operation S50, the mask may be completed by performing a series of processes. For example, the series of processes may include, for example, a development process, an etching process, a cleaning process, and the like. In addition, the series of processes for mask production may include a measurement process and a defect inspection and repair process. In addition, the series of processes for mask production may include a thin film coating process. Here, the thin film coating process may refer to a process in which a thin film is attached to the mask surface to protect the mask from possible contamination during mask delivery and the usable life of the mask when it is confirmed by final cleaning and inspection that there are no contaminating particles and chemical stains.

[0093] In the mask manufacturing method according to some embodiments, the OPC method may include a method of forming a CS-OPC pattern (CS-OPC / OP) by rounding the corners of each first OPC pattern (OPC / OP) formed by the baseline OPC. In addition, in the OPC method, each first OPC pattern (OPC / OP) formed by the baseline OPC may be separated from each other in the extension direction of the line pattern, and the OPC method according to some embodiments may include an operation of forming a LEOCS-OPC pattern (LEOCS-OPC / OP) for thinning the OPC pattern (OPC / OP) at the line end portion of the line patterns adjacent to each other. Therefore, the mask manufacturing method according to the example embodiment can ensure that the target pattern with a critical pitch has sufficient large-scale production margin so that a mask capable of realizing a target pattern with a critical pitch can be manufactured by single exposure patterning. In particular, according to the mask manufacturing method of the example embodiment, even if the target pattern with a critical pitch is realized by single exposure patterning in the EUV process, a reliable EUV mask that does not generate P / O defects and wiring bridging defects can be produced.

[0094] As used herein, the terms "comprise", "contain", "include", "cover", "have", "have" and any other variants thereof specify the features, steps, operations, elements, parts and / or groups, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts and / or groups thereof. It should be understood that although the terms "first" and "second" can be used herein to describe various elements, these elements should not be limited by these terms. On the contrary, these terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, the first element can be referred to as the second element, and similarly, the second element can be referred to as the first element.

[0095] While the inventive concept has been particularly shown and described with reference to various example embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the scope of the appended claims.

Claims

1. An OPC method, wherein the OPC is optical proximity correction, and the method comprises: receiving a design layout of a target pattern to be formed on a substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; as well as The second OPC pattern is obtained by curving the first OPC pattern.

2. The OPC method according to claim 1, wherein: The first OPC pattern includes straight edges.

3. The OPC method according to claim 1, wherein: The second OPC pattern includes a curved edge.

4. The OPC method according to claim 1, wherein: Curving the first OPC pattern includes a curvature-based corner rounding method.

5. The OPC method according to claim 1, further comprising: obtaining a simulated profile of the second OPC pattern; as well as A determination is made as to whether defects are present in the simulated profile. 6 . The OPC method of claim 5 , further comprising modifying the first OPC pattern when a defect exists. 7 . The OPC method according to claim 5 , further comprising determining the second OPC pattern as a final OPC pattern when no defect exists.

8. An OPC method, wherein the OPC is optical proximity correction, the method comprising: receiving a design layout of a target pattern to be formed on a substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; Obtaining a second OPC pattern by curving line ends of the first OPC pattern; obtaining a simulated profile of the second OPC pattern; as well as A determination is made as to whether defects are present in the simulated profile.

9. The OPC method according to claim 8, wherein: Obtaining the second OPC pattern comprises: identifying the line end; separating the line ends from the line pattern; and The separated line ends are rounded.

10. The OPC method according to claim 9, wherein: identifying the line end by a first distance and a second distance, The first distance is the distance between the line end and the line end adjacent to it in a first horizontal direction parallel to the extending direction of the first OPC pattern, and The second distance is a distance between the line end and a line pattern adjacent thereto in a second horizontal direction different from the first horizontal direction.

11. The OPC method according to claim 8, wherein: Obtaining the second OPC pattern includes performing a first design rule check to measure at least one of an edge, a corner, a size, or a relative position of the first OPC pattern. 12 . The OPC method of claim 9 , further comprising performing a second design rule check on each of the line ends and the line patterns that are separated and corner-rounded.

13. The OPC method according to claim 9, wherein: Obtaining the second OPC pattern further includes coupling the line ends separated by corner rounding and the line pattern to each other.

14. The OPC method according to claim 8, wherein: The first OPC pattern includes straight edges, and Wherein, the second OPC pattern includes a straight edge and a curved edge.

15. The OPC method according to claim 9, wherein: A height of a bending line end of the second OPC pattern in a first horizontal direction is less than or equal to half of a width of the bending line end in a second horizontal direction different from the first horizontal direction.

16. The OPC method according to claim 8, wherein: A distance between a line end of the second OPC pattern and a line pattern adjacent thereto is greater than a distance between the line end of the first OPC pattern and a line pattern adjacent thereto.

17. The OPC method according to claim 8, wherein: A distance between the line end of the first OPC pattern and a line pattern adjacent thereto is equal to a distance between the line end of the second OPC pattern and a line pattern adjacent thereto.

18. A method for manufacturing a mask, the method comprising: performing an OPC method to obtain an optical proximity corrected design layout of a target pattern to be formed on a substrate, the OPC being optical proximity correction; transferring data about the optical proximity corrected design layout as mask tape-out design data; preparing mask data based on the mask tape-out design data; as well as exposing the mask substrate based on the mask data, Wherein, executing the OPC method comprises: receiving a design layout of the target pattern to be formed on the substrate; obtaining a first OPC pattern by performing a baseline OPC on the design layout; and The second OPC pattern is obtained by curving opposite line ends of the first OPC pattern.

19. The mask manufacturing method according to claim 18, wherein: The mask is manufactured so that the target pattern is formed on the substrate through a single extreme ultraviolet exposure process.

20. The mask manufacturing method according to claim 18, wherein: Among a plurality of corresponding separation distances between opposite line ends of the second OPC pattern, at least two corresponding separation distances are different from each other.

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