Method of determining a best focus and best dose in exposure process

Abstract

The method for determining optimal focus and optimal dose of the present disclosure comprises: selecting a selection pattern in first and second shot regions of a wafer for splitting; measuring the CD value of the selection pattern to derive a measured CD value; calculating an effective CD value of the selection pattern for each of the first and second shot regions using the measured CD value; calculating an upper CD value and a lower CD value of the selection pattern using the effective CD value of the selection pattern; calculating a process window area for the first shot region and a process window area for the second shot region using the upper CD value and the lower CD value of the selection pattern; and comparing the process window area for the first shot region and the process window area for the second shot region.

Description

Technology Field

[0001] The present disclosure relates to a method for determining the optimal focus and optimal dose of an exposure process. More specifically, the present disclosure relates to a method for determining the optimal focus and optimal dose of an exposure process without a target CD value. Background Technology

[0002] Recently, with the high integration of semiconductor devices, various lithography techniques are being developed to form finer patterns. As the integration density of semiconductor devices increases, the critical dimension (CD) of photoresist patterns becomes smaller; consequently, it is necessary to set up the lithography process precisely and reliably to improve the CD uniformity of photoresist patterns with fine CDs. The problem to be solved

[0003] The object of the present invention is to provide a method for determining the optimal focus and optimal dose of an exposure process without a target CD value. means of solving the problem

[0004] A method for determining an optimal focus and an optimal dose according to embodiments of the present disclosure may include: selecting a selection pattern in first and second shot regions of a wafer for splitting; measuring the CD value of the selection pattern to derive a measured CD value; calculating an effective CD value of the selection pattern for each of the first and second shot regions using the measured CD value; calculating an upper CD value and a lower CD value of the selection pattern using the effective CD value of the selection pattern; calculating a process window area for the first shot region and a process window area for the second shot region using the upper CD value and the lower CD value of the selection pattern; and comparing the process window area for the first shot region and the process window area for the second shot region.

[0005] A method for determining an optimal focus and an optimal dose according to embodiments of the present disclosure may include: selecting a first selection pattern and a second selection pattern of a first shot area of ​​a wafer for splitting, and selecting a first selection pattern and a second selection pattern of a second shot area of ​​the wafer for splitting; calculating upper CD values ​​and lower CD values ​​of the first selection pattern of the first shot area, the second selection pattern of the first shot area, the first selection pattern of the second shot area, and the second selection pattern of the second shot area; calculating a process window area for the first shot area and a process window area for the second shot area using the upper CD values ​​and the lower CD values; and comparing the process window area for the first shot area and the process window area for the second shot area.

[0006] A method for determining an optimal focus and an optimal dose according to embodiments of the present disclosure may include: exposing a first shot area of ​​a split wafer to a first focus value and a first dose value, and exposing a second shot area of ​​the split wafer to a second focus value and a second dose value; selecting a first selection pattern and a second selection pattern of the first shot area, and selecting a first selection pattern and a second selection pattern of the second shot area; measuring CD values ​​of the first selection pattern of the first shot area and the first selection pattern of the second shot area to derive first measured CD values, and measuring CD values ​​of the second selection pattern of the first shot area and the second selection pattern of the second shot area to derive second measured CD values; deriving a first effective CD function using the first measured CD values ​​and deriving a second effective CD function using the second measured CD values; and calculating effective CD values ​​of the first and second shot areas using the first effective CD function and the second effective CD function. Effects of the invention

[0007] A method according to some embodiments of the present disclosure can calculate effective CD values ​​of selection patterns using measured CD values ​​of selection patterns without a target CD value by making the number of selection patterns sufficiently large, and can determine an optimal focus value and an optimal dose value that maximize the area of ​​the process window using the effective CD values ​​of selection patterns. Brief explanation of the drawing

[0008] FIG. 1 is a flowchart of a method for determining the optimal focus and optimal dose of an exposure process according to some embodiments of the present disclosure. Figure 2 is a detailed flowchart of a method for measuring the measurement CD value of a selection pattern. Figure 3 is a drawing illustrating a wafer for splitting. Figures 4a and 4b are drawings for explaining the shot area. Figures 5a and 5b are drawings illustrating a fitting surface plotted using a measured CD value. Figures 6a and 6b are drawings for explaining window calculation diagrams. Figure 7 is a drawing illustrating a window fitting surface. FIG. 8 is a block diagram of a memory card including an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure. FIG. 9 is a block diagram of a memory system employing a memory card comprising an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure. Specific details for implementing the invention

[0009] FIG. 1 is a flowchart of a method for determining the optimal focus and optimal dose of an exposure process according to some embodiments of the present disclosure.

[0010] Referring to FIG. 1, a method for determining the optimal focus and dose of an exposure process may include measuring the measured CD value of a selection pattern (S100), deriving an effective CD function of a selection pattern using the measured CD value of the selection pattern (S200), calculating the effective CD value of a selection pattern using the effective CD function of the selection pattern (S300), calculating the upper CD value and lower CD value of a selection pattern using the effective CD value of the selection pattern (S400), plotting a window calculation diagram using the upper CD value and lower CD value of the selection pattern (S500), calculating the process window area using the window calculation diagram (S600), and determining the optimal focus / dose value (S700).

[0011] In the manufacture of a semiconductor device, a photoresist pattern can be formed by performing an exposure and development process on a photoresist film, and a film to be etched can be patterned using the photoresist pattern as an etching mask. A method according to FIG. 1 may be provided to determine an optimal focus value and an optimal dose value for an exposure process to form a photoresist pattern.

[0013] FIG. 2 is a detailed flowchart of a method for measuring the measured CD value of a selection pattern. FIG. 3 is a diagram illustrating a wafer for splitting. FIG. 4a and 4b are diagrams illustrating a shot area.

[0014] Referring to FIG. 2, measuring the measured CD value of a selected pattern (S100) may include preparing a wafer for splitting that includes shot regions (S110), forming split patterns in the shot regions (S120), selecting selected patterns among the split patterns (S130), and measuring the measured CD values ​​of the selected patterns (S140).

[0015] Referring to FIGS. 2 and 3, a split wafer (SW) may be prepared (S110). The split wafer (SW) may include a photoresist film. The photoresist film of the split wafer (SW) may include a plurality of shot regions (SR). The shot regions (SR) may include first to nth shot regions (SR1, SR2, SR3, SR4, SR5, SR6, ..., SRn). In some embodiments, the split wafer (SW) may be a focus-exposure matrix (FEM) wafer.

[0016] Each of the shot regions (SR) of the wafer (SW) for splitting may be a region exposed to one of a plurality of focus values ​​and one of a plurality of dose values. In some embodiments, the focus values ​​may include first to seventh focus values ​​(F1, F2, F3, F4, F5, F6, F7), and the dose values ​​may include first to eighth dose values ​​(D1, D2, D3, D4, D5, D6, D7, D8). The first to seventh focus values ​​(F1, F2, F3, F4, F5, F6, F7) may be sequentially increasing values. For example, the first to seventh focus values ​​(F1, F2, F3, F4, F5, F6, F7) may be -0.145 µm, -0.13 µm, -0.115 µm, -0.1 µm, -0.085 µm, -0.07 µm, and -0.055 µm, respectively. The first to eighth dose values ​​(D1, D2, D3, D4, D5, D6, D7, D8) may be sequentially increasing values. For example, the first to eighth dose values ​​(D1, D2, D3, D4, D5, D6, D7, D8) may be 26.8 mJ / cm², respectively. 2 , 27.8 mJ / cm² 2 , 28.8 mJ / cm² 2 , 29.8 mJ / cm² 2 , 30.8 mJ / cm² 2 , 31.8 mJ / cm² 2 , 32.8 mJ / cm² 2 , 33.8 mJ / cm² 2 It could be.

[0017] In the present disclosure, the number of focus values ​​of the wafer (SW) for splitting may not be limited to 7. For example, the number of focus values ​​may be 6 or fewer, or 8 or more. In the present disclosure, the number of dose values ​​of the wafer (SW) for splitting may not be limited to 8. For example, the number of dose values ​​may be 7 or fewer, or 9 or more. For convenience of explanation, the case where the number of focus values ​​of the wafer (SW) for splitting is 7 and the number of dose values ​​is 8 is described as an example.

[0018] Referring to FIGS. 2, 3, 4a and 4b, split patterns (SP) can be formed in each shot area (SR) of a wafer (SW) for splitting (S120). For each shot area (SR), an exposure process can be performed with a corresponding focus value and dose value, and a development process can be performed. For example, the first shot area (SR1) can be exposed with a seventh focus value (F7) and a third dose value, and the sixth shot area (SR6) can be exposed with a sixth focus value (F6) and a third dose value (D3). Split patterns (SP) can be formed for each shot area (SR) under different conditions for the focus value and dose value.

[0019] In each shot area (SR), split patterns (SP) can be formed such that the number of split patterns (SP) is equal to each other. For example, the number of split patterns (SP) formed in the first shot area (SR1, see FIG. 4a) may be equal to the number of split patterns (SP) formed in the sixth shot area (SR6, see FIG. 4b).

[0020] In each shot area (SR), split patterns (SP) can be formed such that their relative positions are the same. For example, the relative position of the split patterns (SP) formed in the first shot area (SR1) with respect to the first shot area (SR1) may be the same as the relative position of the split patterns (SP) formed in the sixth shot area (SR6) with respect to the sixth shot area (SR6).

[0021] In each shot area (SR), some of the split patterns (SP) can be selected (S130). The selected split patterns (SP) can be defined as selection patterns. In each shot area (SR), the first to m selection patterns (SEP1, SEP2, SEP3, ..., SEPm) can be selected. For example, the first to m selection patterns (SEP1, SEP2, SEP3, ..., SEPm) can be selected in the first shot area (SR1), and the first to m selection patterns (SEP1, SEP2, SEP3, ..., SEPm) can be selected in the sixth shot area (SR6).

[0022] Each of the first through m selection patterns (SEP1, SEP2, SEP3, ..., SEPm) may be placed at the same relative position in their respective corresponding shot regions (SR). For example, the relative position of the first selection pattern (SEP1) in the first shot region (SR1) with respect to the first shot region (SR1) may be the same as the relative position of the first selection pattern (SEP1) in the sixth shot region (SR6) with respect to the sixth shot region (SR6).

[0023] In some embodiments, among the split patterns (SP), those with a relatively high probability of process defects can be selected as selected patterns (SEP1, SEP2, SEP3, ..., SEPm). For example, a split pattern (SP) that is relatively close to another split pattern (SP) can be selected. For another example, a split pattern (SP) having the smallest pitch size among the split patterns (SP) can be selected.

[0024] For each shot area (SR), the CD value of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) can be measured (S140). For example, the CD value of the first selection pattern (SEP1) of the first shot area (SR1) can be measured, and the CD value of the first selection pattern (SEP1) of the sixth shot area (SR6) can be measured. The measured CD value can be defined as the measured CD value. When the CD values ​​of all the first to m selection patterns (SEP1, SEP2, SEP3, ..., SEPm) are measured, the measured CD values ​​as shown in Table 1 below can be measured.

[0025] SR1 SR2 SR3 ... SRn SEP1 MCD11 MCD21 MCD31 ... MCDn1 SEP2 MCD12 MCD22 MCD32 ... MCDn2 SEP3 MCD13 MCD23 MCD33 ... MCDn3 ... ... ... ... ... ... SEPm MCD1m MCD2m MCD3m ... MCDnm

[0027] As shown in Table 1, the measured CD values ​​of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) for each of the first to nth shot regions (SR1, SR2, SR3, ..., SRn) can be measured. The measured CD values ​​for the first selection patterns (SEP1) can be defined as the first measured CD values ​​(MCD11, MCD21, MCD31, ..., MCDn1), the measured CD values ​​for the second selection patterns (SEP2) can be defined as the second measured CD values ​​(MCD12, MCD22, MCD32, ..., MCDn2), the measured CD values ​​for the third selection patterns (SEP3) can be defined as the third measured CD values ​​(MCD13, MCD23, MCD33, ..., MCDn3), and the measured CD values ​​for the m-th selection patterns (SEPm) can be defined as the m-th measured CD values ​​(MCD1m, MCD2m, MCD3m, ..., MCDnm).

[0029] Figures 5a and 5b are drawings illustrating a fitting surface plotted using a measured CD value.

[0030] Referring to FIGS. 1, 5a and 5b, effective CD functions for each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) can be derived using the measured CD values ​​of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) (S200). For example, a first effective CD function ECD1(F,D) for the first selection pattern (SEP1) can be derived using the first measured CD values ​​(MCD11, MCD21, MCD31, ..., MCDn1) of the first selection pattern (SEP1), and a second effective CD function ECD2(F,D) for the second selection pattern (SEP2) can be derived using the second measured CD values ​​(MCD12, MCD22, MCD32, ..., MCDn2) of the second selection pattern (SEP2). Effective CD functions may be functions of a focus value F and a dose value D. In other words, effective CD functions may be dependent on a focus value F and a dose value D. Here, the focus value F may be a continuous variable having a range between, for example, a first focus value (F1) and a seventh focus value (F7), and the dose value D may be a continuous variable having a range between, for example, a first dose value (D1) and an eighth dose value (D8).

[0031] Effective CD functions can be derived through a data fitting procedure. For example, a first effective CD function ECD1(F,D) can be derived through a data fitting procedure of first measured CD values ​​(MCD11, MCD21, MCD31, ..., MCDn1).

[0032] In some embodiments, a fitting surface for each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) can be plotted through a data fitting procedure of the measured CD values. The fitting surface may represent an effective CD value according to the focus value and the dose value. For example, as shown in FIG. 5a, a first fitting surface (FS1) can be plotted using the measured CD values ​​(MCD), and as shown in FIG. 5b, a second fitting surface (FS2) can be plotted using the measured CD values ​​(MCD). The fitting surface for each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) may correspond to an effective CD function for the corresponding selection pattern. For example, the fitting surface for the first selection pattern (SEP1) may correspond to a first effective CD function ECD(F,D) for the first selection pattern (SEP1).

[0033] The effective CD value of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) for each shot area (SR1, SR2, SR3, ..., SRn) can be calculated (S300). The effective CD value can be calculated by substituting the focus value and dose value of each shot area (SR1, SR2, SR3, ..., SRn) into the effective CD function of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) derived above. For example, the effective CD value ECD11 of the first selection pattern (SEP1) of the first shot area (SR1) can be calculated by substituting the seventh focus value (F7) and the third dose value (D3) into the first effective CD function ECD1(F,D). The effective CD values ​​of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) for each shot area (SR) can be calculated as shown in Table 2 below.

[0034] SR1 SR2 SR3 ... SRn SEP1 ECD11 ECD21 ECD31 ... ECDn1 SEP2 ECD12 ECD22 ECD32 ... ECDn2 SEP3 ECD13 ECD23 ECD33 ... ECDn3 ... ... ... ... ... ... SEPm ECD1m ECD2m ECD3m ... ECDnm

[0036] To explain, the effective CD value of the first selection pattern (SEP1) for the first shot area (SR1) may be ECD11, and the effective CD value of the second selection pattern (SEP2) for the second shot area (SR2) may be ECD22.

[0037] Using the effective CD values ​​(ECD11, ..., ECDnm), upper CD values ​​and lower CD values ​​can be calculated (S400). Each upper CD value may be X% greater than the corresponding effective CD value. For example, the upper CD value (UL11) of the first selection pattern (SEP1) for the first shot area (SR1) may be X% greater than the effective CD value (ECD11) of the first selection pattern (SEP1) for the first shot area (SR1) (i.e., UL11 = ECD11*(100+X) / 100). Each lower CD value may be X% smaller than the corresponding effective CD value. For example, the lower limit CD value (LL11) of the first selection pattern (SEP1) for the first shot area (SR1) may be X% smaller than the effective CD value (ECD11) of the first selection pattern (SEP1) for the first shot area (SR1) (i.e., LL11 = ECD11 * (100 - X) / 100). Here, X may be determined as an appropriate number considering the range of the process window, defects in the photoresist pattern, etc. For example, X may be 5.

[0038] The upper CD values ​​of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) for each shot area (SR1, SR2, SR3, ..., SRn) can be calculated as shown in Table 3 below.

[0039] SR1 SR2 SR3 ... SRn SEP1 UL11 UL21 UL31 ... ULn1 SEP2 UL12 UL22 UL32 ... ULn2 SEP3 UL13 UL23 UL33 ... ULn3 ... ... ... ... ... ... SEPm UL1m UL2m UL3m ... ULnm

[0041] The lower CD values ​​of each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) for each shot area (SR1, SR2, SR3, ..., SRn) can be calculated as shown in Table 4 below.

[0042] SR1 SR2 SR3 ... SRn SEP1 LL11 LL21 LL31 ... LLn1 SEP2 LL12 LL22 LL32 ... LLn2 SEP3 LL13 LL23 LL33 ... LLn3 ... ... ... ... ... ... SEPm LL1m LL2m LL3m ... LLnm

[0044] 6a and 6b are drawings to explain the window calculation diagram.

[0045] Referring to FIGS. 6a and 6b, a window calculation diagram (WC) for each shot area (SR) can be plotted using upper CD values, lower CD values, an effective CD function, and a fitting surface (S500). For example, FIG. 6a may be a window calculation diagram (WC) for the first shot area (SR1), and FIG. 6b may be a window calculation diagram (WC) for the sixth shot area (SR6).

[0046] The window calculation diagram (WC) may include upper curves (UC) and lower curves (LC). The upper curves (UC) and lower curves (LC) may be bossung curves. For each shot area (SR), the upper curves (UC) may represent focus and dose values ​​such that each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) has an upper CD value. For each shot area (SR), the lower curves (LC) may represent focus and dose values ​​such that each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) has a lower CD value.

[0047] For example, referring to FIG. 6a, in the window calculation diagram (WC) for the first shot area (SR1), each upper curve (UC) may represent a focus value and dose value such that each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) has a corresponding upper CD value (UL11, UL12, UL13, ..., UL1m), and each lower curve (LC) may represent a focus value and dose value such that each selection pattern (SEP1, SEP2, SEP3, ..., SEPm) has a corresponding lower CD value (LL11, LL12, LL13, ..., LL1m). More specifically, for example, the upper limit curve (UC) for the first selection pattern (SEP1) of the first shot area (SR1) can represent a focus value and a dose value such that the first selection pattern (SEP1) of the first shot area (SR1) has an upper limit CD value (UL11).

[0048] For convenience of explanation, only three upper limit curves (UC) and three lower limit curves (LC) are shown in FIG. 6a, but the number of upper limit curves (UC) and lower limit curves (LC) can be plotted to be equal to the number of selection patterns (SEP1, SEP2, SEP3, ..., SEPm). As another example, upper limit curves (UC) and lower limit curves (LC) for selection patterns of the sixth shot area (SR6) can be plotted in FIG. 6b.

[0049] The window calculation diagram (WC) may further include a first focus limit line (FL1), a second focus limit line (FL2), a first dose limit line (DL1), and a second dose limit line (DL2). The first and second focus limit lines (FL1, FL2) may be plotted according to the maximum focus value and minimum focus value of the exposure process for forming split patterns (SP). The first and second dose limit lines (DL1, DL2) may be plotted according to the maximum dose value and minimum dose value of the exposure process for forming split patterns (SP).

[0050] For example, referring to FIG. 6a, in the window calculation diagram (WC) for the first shot area (SR1), the first focus limit line (FL1) can be plotted along the first focus value (F1), the second focus limit line (FL2) can be plotted along the seventh focus value (F7), the first dose limit line (DL1) can be plotted along the first dose value (D1), and the second dose limit line (DL2) can be plotted along the eighth dose value (D8).

[0051] Using a window calculation diagram (WC), the process window area (PWA) for each shot area (SR) can be calculated (S600). The process window area (PWA) may represent a process window according to the focus value and dose value exposed to the corresponding shot area (SR). In each shot area (SR), the process window area (PWA) may be an area containing an exposure condition point (ECO) corresponding to the focus value and dose value exposed to the corresponding shot area (SR).

[0052] For example, referring to FIG. 6a, the process window area (PWA) in the first shot area (SR1) may include an exposure condition point (ECO) corresponding to a seventh focus value (F7) and a third dose value (D3) at which the first shot area (SR1) is exposed. For another example, referring to FIG. 6b, the process window area (PWA) in the sixth shot area (SR6) may include an exposure condition point (ECO) corresponding to a sixth focus value (F6) and a third dose value (D3) at which the sixth shot area (SR6) is exposed.

[0053] The process window area (PWA) may be defined by at least some of upper curves (UC), lower curves (LC), first and second focus limits (FL1, FL2), and first and second dose limits (DL1, DL2). The process window area (PWA) may be an area enclosed by at least some of the upper curves (UC), lower curves (LC), first and second focus limits (FL1, FL2), and first and second dose limits (DL1, DL2).

[0054] For example, referring to FIG. 6a, the process window area (PWA) of the first shot area (SR1) may be an area defined by an upper curve (UC), a lower curve (LC), a first dose limit line (DL1), and a second focus limit line (FL2). For another example, referring to FIG. 6b, the process window area (PWA) of the sixth shot area (SR6) may be an area defined by two upper curves (UC) and two lower curves (LC).

[0055] For each of the shot areas (SR), a process window area (PWA) can be calculated. Since each shot area (SR) has different exposure focus and dose values, a process window area (PWA) for different focus and dose values ​​can be calculated. For example, the process window area (PWA) of FIG. 6a can be defined as the process window area (PWA) for the seventh focus value (F7) and the third dose value (D3), and the process window area (PWA) of FIG. 6b can be defined as the process window area (PWA) for the sixth focus value (F6) and the third dose value (D3).

[0056] Next, for each of the shot areas (SR), the ratio of the process window area can be calculated as shown in Table 5 below.

[0057] SR1 SR2 SR3 ... SRn PWAr1 PWAr2 PWAr3 ... PWArn

[0059] Referring to 7, a window fitting surface (WFS) can be plotted through a data fitting procedure of the ratios of process window areas (PWAr1, PWAr2, PWAr3, ..., PWArn) for each shot area (SR1, SR2, SR3, ..., SRn) calculated as above. The window fitting surface (WFS) can represent the ratio of the process window area (PWA ratio) for each shot area (SR1, SR2, SR3, ..., SRn). The window fitting surface (WFS) can represent the ratio of the process window area (PWA ratio) to the focus value and dose value to which each shot area (SR1, SR2, SR3, ..., SRn) is exposed. In some embodiments, a function of the ratio of the process window area to the focus value and dose value can be derived together with the window fitting surface (WFS).

[0060] By using a window fitting surface (WFS), the optimal condition point (BCO) at which the process window area ratio (PWA ratio) is maximized can be derived, and the focus value and dose value at which the process window area ratio (PWA ratio) is maximized can be derived. Alternatively, by using a function of the process window area ratio, the focus value and dose value at which the process window area ratio is maximized can be derived.

[0061] The focus value and dose value that maximize the process window area ratio (PWA ratio) can be determined as the optimal focus value and optimal dose value for the exposure process (S700). In other words, the focus value and dose value that maximize the process window area can be determined as the optimal focus value and optimal dose value for the exposure process.

[0062] As described above, by comparing the process window areas for all shot areas (SR1, SR2, SR3, ..., SRn), the optimal focus value and optimal dose value with the largest process window area can be determined. In an extreme ultraviolet (EUV) exposure process, the optimal focus value and optimal dose value can be determined by the above method.

[0063] Depending on the value of X for calculating the upper CD values ​​and lower CD values, the upper curves (UC) and lower curves (LC) of the window calculation diagram (WC) may vary, and the process window area (PWA) may vary, so the derived optimal focus value and optimal dose value may vary.

[0064] The method according to the embodiments of the present disclosure can derive a stable effective CD function and a fitting surface using the measured CD values ​​of the selected patterns by making the number of selected patterns among the split patterns sufficiently large (e.g., m > 50). Accordingly, the effective CD values ​​of the selected patterns can be calculated, thereby determining an optimal focus value and an optimal dose value that maximize the area of ​​the process window without a target CD value.

[0065] The method according to the embodiments of the present disclosure can determine the value of X according to CD tolerance, and can determine the optimal focus value and the optimal dose value according to CD tolerance.

[0067] FIG. 8 is a block diagram of a memory card including an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure.

[0068] Referring to FIG. 8, the memory card (1200) may include a memory controller (1220) that generates command and address signals C / A, and a memory module (1210), for example, a flash memory comprising one or more flash memory elements. The memory controller (1220) may include a host interface (1223) that transmits command and address signals to a host or receives these signals from the host, and a memory interface (1225) that transmits command and address signals back to the memory module (1210) or receives these signals from the memory module (1210). The host interface (1223), the controller (1224), and the memory interface (1225) may communicate with a controller memory (1221), such as an SRAM, and a processor (1222), such as a CPU, through a common bus (1228).

[0069] The memory module (1210) receives command and address signals from the memory controller (1220) and, in response, can store data in at least one of the memory elements on the memory module (1210) and retrieve data from at least one of the memory elements. Each memory element may include a plurality of addressable memory cells and a decoder that receives command and address signals and generates row and column signals to access at least one of the addressable memory cells during programming and read operations.

[0070] Each component of the memory card (1200) including the memory controller (1220), electronic elements (1221, 1222, 1223, 1224, 1225) included in the memory controller (1220), and at least one of the memory module (1210) may include an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure.

[0072] FIG. 9 is a block diagram of a memory system employing a memory card comprising an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure.

[0073] The memory system (1300) may include a processor (1330), such as a CPU, communicating via a common bus (1360), a random access memory (1340), a user interface (1350), and a modem (1320). Each of the above components may transmit a signal to a memory card (1310) via the common bus (1360) and receive a signal from the memory card (1310). At least one of each component of the memory system (1300), including the processor (1330), the random access memory (1340), the user interface (1350), and the modem (1320) together with the memory card (1310), may include an integrated circuit element manufactured through a photolithography process according to some embodiments of the present disclosure.

[0074] The memory system (1300) can be applied to various electronic applications. For example, it can be applied to SSDs (solid state drives), CIS (CMOS image sensors), and computer application chipsets.

[0075] Memory systems and devices according to some embodiments of the present disclosure may be packaged in any of various device package forms, including, for example, BGA (ball grid arrays), CSP (chip scale packages), PLCC (plastic leaded chip carrier), PDIP (plastic dual in-line package), MCP (multi-chip package), WFP (wafer-level fabricated package), WSP (wafer-level processed stock package), etc., but are not limited to those exemplified above.

[0076] Although embodiments according to the technical concept of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. The embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0077] SW: Wafer for splitting SR: Shot Area SP: Split Pattern

Claims

Claim 1 Selecting a selection pattern in first and second shot regions of a wafer for splitting, wherein the selection pattern includes first selection patterns and second selection patterns that are included in each of the first and second shot regions and are positioned at relatively the same location; measuring the CD value of the selection pattern to derive a measured CD value; calculating an effective CD value of the selection pattern for each of the first and second shot regions using the measured CD value; calculating an upper CD value and a lower CD value of the selection pattern using the effective CD value of the selection pattern; and calculating a process window area for the first shot region and a process window area for the second shot region using the upper CD value and the lower CD value of the selection pattern. A method for determining an optimal focus and an optimal dose, wherein each of the shot areas is exposed to one focus value among a plurality of focus values ​​and one dose value among a plurality of dose values. The method includes comparing the process window area for the first shot area and the process window area for the second shot area, wherein the split wafer includes a plurality of shot areas including the first and second shot areas, and each of the shot areas is exposed to one focus value among a plurality of focus values ​​and one dose value among a plurality of dose values. Claim 2 delete Claim 3 A method for determining optimal focus and optimal dose according to claim 1, wherein deriving the measured CD values ​​comprises: measuring the CD values ​​of the first selection patterns to derive the first measured CD values; and measuring the CD values ​​of the second selection patterns to derive the second measured CD values. Claim 4 A method for determining optimal focus and optimal dose according to claim 1, wherein calculating the effective CD value includes deriving an effective CD function through a data fitting procedure of the measured CD value. Claim 5 A method for determining optimal focus and optimal dose according to claim 1, wherein calculating the process window area for the first shot area and the process window area for the second shot area comprises plotting a window calculation diagram for each of the first and second shot areas. Claim 6 In claim 5, the window calculation diagram is a method for determining optimal focus and optimal dose, including an upper curve and a lower curve. Claim 7 A method for determining optimal focus and optimal dose according to claim 6, wherein the upper limit curve is plotted based on the upper limit CD value and the lower limit curve is plotted based on the lower limit CD value. Claim 8 In claim 6, the process window area for the first shot area and the process window area for the second shot area are a method for determining the optimal focus and optimal dose, which are defined by the upper curve and the lower curve. Claim 9 A method for determining an optimal focus and an optimal dose according to claim 1, further comprising determining an optimal focus and an optimal dose of an extreme ultraviolet exposure process. Claim 10 Selecting a first selection pattern and a second selection pattern of a first shot area of ​​a wafer for splitting, and selecting a first selection pattern and a second selection pattern of a second shot area of ​​the wafer for splitting; calculating upper CD values ​​and lower CD values ​​of the first selection pattern of the first shot area, the second selection pattern of the first shot area, the first selection pattern of the second shot area, and the second selection pattern of the second shot area; and calculating a process window area for the first shot area and a process window area for the second shot area using the upper CD values ​​and the lower CD values. A method for determining an optimal focus and an optimal dose, comprising comparing the process window area for the first shot area and the process window area for the second shot area, wherein the split wafer includes a plurality of shot areas including the first and second shot areas, each of the shot areas is exposed to one focus value among a plurality of focus values ​​and one dose value among a plurality of dose values, and each of the first selection pattern of the first shot area and the second selection pattern of the first shot area is placed at the same position relative to the first selection pattern of the second shot area and the second selection pattern of the second shot area.

Images