CN116184773A - Risk prediction and optimization method for SRAF (SRAF) - Google Patents

Risk prediction and optimization method for SRAF (SRAF) Download PDF

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Publication number
CN116184773A
CN116184773A CN202310113535.9A CN202310113535A CN116184773A CN 116184773 A CN116184773 A CN 116184773A CN 202310113535 A CN202310113535 A CN 202310113535A CN 116184773 A CN116184773 A CN 116184773A
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sraf
test pattern
optimization method
pattern structure
light intensity
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Chinese (zh)
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邹先梅
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Shanghai Huali Integrated Circuit Manufacturing Co Ltd
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Shanghai Huali Integrated Circuit Manufacturing Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70491—Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
    • G03F7/705—Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70425—Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
    • G03F7/70433—Layout for increasing efficiency or for compensating imaging errors, e.g. layout of exposure fields for reducing focus errors; Use of mask features for increasing efficiency or for compensating imaging errors
    • G03F7/70441—Optical proximity correction [OPC]
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70491—Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
    • G03F7/70508—Data handling in all parts of the microlithographic apparatus, e.g. handling pattern data for addressable masks or data transfer to or from different components within the exposure apparatus

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  • General Physics & Mathematics (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)

Abstract

The invention discloses a risk prediction and optimization method for SRAF, which comprises the following steps: step one, designing a series of first test pattern structures, wherein the first test pattern structures comprise first dense pattern areas, spacing areas and second dense pattern areas, and the widths of the spacing areas are gradually changed. And step two, inserting SRAF into the interval area of each first test pattern structure and performing OPC correction. And thirdly, simulating a simulation contour map of each first test pattern structure by utilizing an OPC result checking program. Fourth, carry on the risk judgement, including: if the simulated contour map does not include the contour map of the SRAF, the verification result is safe. If the simulated contour diagram comprises the contour diagram of the SRAF, the verification result is unsafe, and the step five is carried out; and step five, optimizing the parameters of the SRAF with unsafe parameters, and then turning to step two. The invention can accurately verify the parameter safety of the SRAF under various environments in advance, optimize the unsafe parameter of the SRAF, and ensure the safety of inserting the SRAF in the product layout.

Description

Risk prediction and optimization method for SRAF (SRAF)
Technical Field
The present invention relates to a method for manufacturing a semiconductor integrated circuit, and more particularly, to a method for predicting and optimizing risk of sub-resolution-assisted-feature (SRAF) patterns.
Background
With the progressive decrease of technology nodes, SRAFs are typically added to improve the resolution of photolithography processes, depth of focus (DOF) of the pattern, and process windows of semi-dense and isolated (iso) patterns. Generally, when the whole process flow is optimized by using the SRAF pattern, the SRAF pattern on the mask cannot be displayed in the whole exposure process, so that defects are avoided to influence the product yield, and therefore it is important to verify the safety of the SRAF adding rule in advance.
The current line layout addition SRAF is mainly based on Rule-based (Rule-based) insertion technology. The parameters of SRAFs inserted through rule_based are mainly related to the space (space) between two patterns, i.e., the SRAFs of the same space are added in the same Rule without special processing, i.e., the space is the same, and the parameters of the inserted SRAFs are the same. However, the difference of the optical effects of different patterns corresponding to the two sides of the space on the SRAF is very large, and the patterns with strong optical effects on the SRAF may cause the SRAF to be exposed in the exposure process, so that defects are caused, and the product yield is affected. The current SRAF addition rules mainly screen the individual parameters of SRAF by designing a grating structure as shown in fig. 2 with a gradually expanding spatial period (Pitch). Because the influence of the grating structure with gradually expanded space period on the optical property of the SRAF is not the largest, the screened SRAF rule cannot be completely suitable for the layouts under different environments, and especially for the situation that the screened SRAF adding rule has extra development (extrapring) in the whole customer layout for the customer layout with complex environment, the SRAF under the risky environment needs to be optimized one by one subsequently. As shown in FIG. 1, the prior method for inserting SRAF in a layout comprises the following steps:
step S101, a series of Test Pattern (TP) structures are designed on a Test mask plate (Test mask). In the test pattern, a grating structure with gradually expanded space period as shown in fig. 2 is adopted as a pattern structure for screening parameters of SRAF, the pattern structure similar to the grating structure comprises a pattern 101, a spacing region 102, the pattern 101 and the spacing region 102 are alternately arranged, and the SRAF103 is arranged in the spacing region 102. The pattern 101 has a line width, i.e., a width W, and the sum of the width W of the pattern 101 and the width of the spacer 102 is a spatial period P.
Step S102, the SRAF rule (rule) corresponding to different space is filtered out, and the light intensity threshold (Ith) of the detection (check) SRAF extraprinting is detected.
The SRAF rule corresponding to different spaces is screened out by using the figure 2, the figure 2 corresponding to the different spaces is formed, and whether the SRAF is safe or not can be determined by simulation, so that parameters of the SRAF are determined.
In general, ith indicates the minimum light intensity at which the SRAF will form additional development, i.e., extrapring, and if the light intensity in the photoresist in the SRAF projection area is greater than Ith after being projected through the mask plate to the photoresist, the photoresist will be exposed, and thus the pattern of the SRAF will be transferred to the photoresist, which is not allowed, so that a safety verification is required to ensure that the maximum light intensity corresponding to the SRAF is reduced below Ith.
And step S103, adding the screened SRAF to the customer layout.
However, SRAF extraprinting exists due to the complexity of the customer layout environment. The following step S104 is required.
Step S104, there is a SRAF extraprinting need to debug (debug) one by one to eliminate SRAF extraprinting.
Obviously, such a one-by-one debug reduces efficiency and may result in misses.
Disclosure of Invention
The technical problem to be solved by the invention is to provide the risk prediction and optimization method for the SRAF, which can accurately verify the parameter safety of the SRAF in various environments in advance and optimize unsafe SRAF parameters, so that the safety of inserting the SRAF into a layout corresponding to a product can be ensured, and the risk of exposing and developing the SRAF is reduced.
In order to solve the above technical problems, the risk prediction and optimization method for SRAF provided by the present invention includes the following steps:
step one, designing a series of first test pattern structures, wherein each first test pattern structure comprises a first Dense pattern area, a spacing area (gap) and a second Dense pattern area, dense patterns (DL) are arranged in the first Dense pattern area and the second Dense pattern area, and the width of the spacing area of each first test pattern structure is gradually changed.
A series of the first test pattern structures are used to simulate different environments in which an SRAF is inserted, and the dense patterns are used to enhance the optical impact on the SRAF under different environments.
And step two, inserting an SRAF into the interval area of each first test pattern structure and performing OPC correction on each first test pattern structure after the SRAF is inserted.
And thirdly, simulating a simulation contour map (contour) of each first test pattern structure by using an OPC result checking program.
Fourth, carry on the risk judgement, including:
and if the simulated contour diagram does not comprise the contour diagram of the SRAF, the verification result is that each parameter of the SRAF is safe.
If the simulated contour diagram comprises the contour diagram of the SRAF, the verification result is that each parameter of the SRAF is unsafe, and the step five is carried out;
and step five, optimizing the parameters of the SRAF with unsafe parameters, turning to step two, and repeating the steps two to four or the steps two to five until each parameter of each SRAF is safe.
The further improvement is that after the second step and before the fourth step, the method further comprises:
and step six, simulating the maximum light intensity value of the SRAF in each first test pattern structure by using an OPC optical model.
In a further improvement, in the first step, the line width and the space period of the dense pattern are set according to the line width and the minimum space period allowed in the design rule of the corresponding critical layer.
In a further improvement, in the second step, the SRAF is inserted by using a rule-based technique.
Further improvement is that the width of the spacer of each first test pattern structure is determined according to the number of inserted SRAFs, and the width of the spacer of each first test pattern structure is gradually changed by gradually changing the number of inserted SRAFs.
In a further improvement, in the first step, the spatial period of the dense pattern is set to be greater than or equal to the minimum spatial period and less than or equal to a first width of the spacer, where the first width is a width of the spacer of the first test pattern structure when 1 SRAF is inserted.
In a further improvement, in the first test pattern structure, the number of the SRAFs that gradually change in the series of the first test pattern structures is 1 to 6.
In the sixth step, when a plurality of SRAFs are disposed in the spacer of the first test pattern structure, the maximum light intensity value is the value with the maximum light intensity of all the SRAFs in the spacer of the first test pattern structure.
In a further improvement, in the second step, the OPC correction is performed by using an OPC optical model with a process window established.
In the third step, the OPC result checking program simulates and simulates a simulated outline map of each first test pattern structure according to the process window and the light intensity threshold of the OPC model.
In a further improvement, the risk determination in the fourth step further includes:
comparing the maximum light intensity value of the SRAF in each first test pattern structure with a light intensity threshold value, and if the maximum light intensity value of the SRAF is smaller than the light intensity threshold value, determining that each parameter of the SRAF is safe according to a theoretical determination result;
if the maximum light intensity value of the SRAF is greater than or equal to the light intensity threshold value, the theoretical judgment result is that each parameter of the SRAF is unsafe, and the step five is carried out;
the theoretical judgment result and the verification result complement each other.
A further improvement is that the intensity threshold employs a minimum intensity value required for the earlier verified SRAF to be developed by exposure.
A further improvement is that in step five, optimizing the parameters of the SRAF includes reducing the width of the SRAF.
According to the invention, a series of first test pattern structures are designed, so that different environments in which SRAF is inserted can be simulated; meanwhile, dense patterns are arranged in a first dense pattern area and a second dense pattern area on two sides of a spacing area in a first test pattern structure, and because the dense patterns have the greatest influence on the SRAF light rays of the spacing area, after the SRAF is inserted into the spacing area in the first test pattern structure, the safety of each parameter of the SRAF can be well verified, and unsafe SRAF parameters which cannot be detected by some existing methods can be well detected and the parameters of the SRAF can be optimized according to detection results; the invention is carried out before inserting SRAF in the layout of the customer product, so the invention can accurately verify the parameter safety of the SRAF in various environments in advance and optimize the unsafe parameter of the SRAF, thereby ensuring the safety of inserting the SRAF in the layout corresponding to the product and reducing the risk of exposing and developing the SRAF.
Drawings
The invention is described in further detail below with reference to the attached drawings and detailed description:
FIG. 1 is a flow chart of a prior art method of inserting SRAFs in a layout;
FIG. 2 is a diagram structure used in screening SRAF parameters in the prior art method of inserting SRAF in a layout;
FIG. 3 is a flow chart of a risk prediction and optimization method for SRAF according to an embodiment of the present invention;
FIG. 4 is a flow chart of a risk prediction and optimization method for SRAF according to the preferred embodiment of the present invention;
FIG. 5 is a schematic diagram of a first test pattern structure used in the risk prediction and optimization method of SRAF according to an embodiment of the present invention;
FIG. 6A is a simulated outline diagram obtained by simulating the graphic structure shown in FIG. 2 in a conventional method of inserting SRAF in a layout;
FIG. 6B is a simulated contour diagram obtained by simulating a first test pattern structure before SRAF optimization in the risk prediction and optimization method of SRAF according to the embodiment of the invention;
FIG. 6C is a simulated contour diagram obtained by simulating a first test pattern structure after SRAF optimization in the risk prediction and optimization method of SRAF according to the embodiment of the present invention;
FIG. 7 is a graph comparing the maximum intensity values of SRAF before and after SRAF optimization in the risk prediction and optimization method of SRAF according to the preferred embodiment of the present invention;
fig. 8 is a table comparing the risk prediction and optimization methods for SRAFs of the present invention to optimize SRAFs of different spatial periods and SRAF extraprinting before and after optimization.
Detailed Description
FIG. 3 is a flowchart of a risk prediction and optimization method for SRAF204 according to an embodiment of the present invention; FIG. 4 is a flowchart of a risk prediction and optimization method for SRAF204 according to the preferred embodiment of the present invention; FIG. 5 is a schematic diagram of a first test pattern structure used in the risk prediction and optimization method of the SRAF204 according to the embodiment of the present invention; the risk prediction and optimization method of the SRAF204 in the embodiment of the invention comprises the following steps:
step one, designing a series of first test pattern structures, wherein each first test pattern structure comprises a first dense pattern region 201a, a spacing region 202 and a second dense pattern region 201b, dense patterns 203 are arranged in the first dense pattern region 201a and the second dense pattern region 201b, and the width of the spacing region 202 of each first test pattern structure is gradually changed. The width of the dense pattern 203 is W, and the spatial period of the arrangement of the dense pattern 203 is P.
A series of the first test pattern structures are used to simulate different environments in which SRAFs 204 are inserted, and the dense patterns 203 are used to enhance the optical impact on the SRAFs 204 under different environments.
In the embodiment of the present invention, the line width and the space period of the dense pattern 203 are set according to the line width and the minimum space period allowed in the design rule of the corresponding critical layer.
In a second, subsequent step, rule-based techniques are used to insert the SRAFs 204. In some embodiments, the width of the spacer 202 of each of the first test pattern structures is determined according to the number of inserted SRAFs 204, and the width of the spacer 202 of each of the first test pattern structures is gradually changed by gradually changing the number of inserted SRAFs 204.
The spatial period of the dense pattern 203 is set to be equal to or greater than the minimum spatial period (Pmin) and equal to or less than a first width (Gap 1) of the spacer 202, the first width being a width of the spacer 202 of the first test pattern structure when 1 SRAF204 is inserted. The formula can be expressed as:
in some embodiments, in the series of first test pattern structures, the number of the SRAFs 204 that gradually changes is 1 to 6, and the widths of the corresponding spacers 202 are respectively Gap1, gap2, gap3, gap4, gap5, and Gap6, and the gaps 1 to Gap6 sequentially increase.
In a preferred embodiment of the present invention, step one corresponds to step S201 in fig. 4, designing a series of patterns of dl_gap_dl structures, DL representing the dense pattern 203, gap representing the spacer 202, dl_gap_dl representing the first test pattern structure.
And step two, inserting an SRAF204 into the interval area 202 of each first test pattern structure, and performing OPC correction on each first test pattern structure after the SRAF204 is inserted.
In the embodiment of the present invention, rule-based techniques are used to insert the SRAFs 204.
In some embodiments, the OPC corrections are performed using an OPC optical model that builds a process window.
In a preferred embodiment of the present invention, step two corresponds to step S202 in fig. 4, and the SRAF is inserted by rule_based technique, and OPC correction is performed on the graph.
And thirdly, simulating a simulation contour map of each first test pattern structure by using an OPC result checking program.
In the embodiment of the invention, the OPC result checking program simulates and simulates the simulated contour map of each first test pattern structure according to the process window and the light intensity threshold value (Ith) of the OPC model.
In some embodiments, the light intensity threshold employs a minimum light intensity value required for the earlier verified SRAF204 to be exposed to light for development.
In the preferred embodiment of the present invention, step three corresponds to step S203 in fig. 4, and the comparison of SRAF is simulated by using the OPC result checking program.
In a preferred embodiment of the present invention, after the second step and before the subsequent fourth step, the method further includes:
and step six, simulating the maximum light intensity value of the SRAF204 in each first test pattern structure by using an OPC optical model.
When a plurality of SRAFs 204 are disposed in the spacer 202 of the first test pattern structure, the maximum light intensity value takes the value of the maximum light intensity of all the SRAFs 204 in the spacer 202 of the first test pattern structure.
Step six corresponds to step S207 in fig. 4, and the maximum light intensity value Imax of SRAF is calculated through simulation, where Imax represents the maximum light intensity value.
Fourth, carry on the risk judgement, including:
if the simulated contour map does not include the contour map of the SRAF204, the verification result is that each parameter of the SRAF204 is safe.
If the simulated contour map includes the contour map of the SRAF204, the verification result is that each parameter of the SRAF204 is unsafe, and go to step five;
in the preferred embodiment of the present invention, step four includes the risk determination in fig. 4 based on step S203, and when no connours are determined, the process goes to step S204 and SRAF parameters are safe; if the determination result is that there is a concour, the process goes to step S205, where each parameter of SRAF is unsafe.
In a preferred embodiment of the present invention, the risk determination further includes:
comparing the maximum light intensity value of the SRAF204 in each first test pattern structure with a light intensity threshold, and if the maximum light intensity value of the SRAF204 is smaller than the light intensity threshold, determining that each parameter of the SRAF204 is safe according to a theoretical determination result;
if the maximum light intensity value of the SRAF204 is greater than or equal to the light intensity threshold, the theoretical determination result is that each parameter of the SRAF204 is unsafe, and go to step five;
in the preferred embodiment of the present invention, step four includes the risk determination in fig. 4 based on step S207, and when Imax < Ith is determined, the process goes to step S204 and SRAF parameters are safe; if the determination result is Imax > Ith, go to step S205, where the SRAF parameters are unsafe.
It can be seen that the theoretical determination result based on step S207 and the verification result based on step S203 complement each other. The risk determination based on step S203 is the verification result since it is determined directly from the simulation structure. The risk determination in step S203 is based on a numerical comparison, and the result can be theoretically deduced, so the result is the theoretical determination result.
Step five, optimizing the parameters of the SRAFs 204 with unsafe parameters, turning to step two, and repeating step two to step four or step two to step five until each parameter of each SRAF204 is safe.
In an embodiment of the present invention, optimizing parameters of the SRAF204 includes reducing the width of the SRAF204.
In the preferred embodiment of the present invention, step five corresponds to step S206, SRAF parameter optimization in fig. 4, and then goes to step S202.
According to the embodiment of the invention, a series of first test pattern structures are designed, so that different environments in which the SRAF204 is inserted can be simulated; meanwhile, dense patterns 203 are arranged in a first dense pattern area 201b and a second dense pattern area 201b on two sides of a spacer 202 in a first test pattern structure, and because the dense patterns 203 have the greatest influence on light rays of SRAF204 of the spacer 202, after the SRAF204 is inserted into the spacer 202 in the first test pattern structure, safety of all parameters of the SRAF204 can be well verified, unsafe SRAF204 parameters which cannot be detected by some existing methods can be well detected, and parameters of the SRAF204 can be optimized according to detection results; the embodiment of the invention is carried out before the SRAF204 is inserted into the layout of the customer product, so that the embodiment of the invention can accurately verify the parameter safety of the SRAF204 in various environments in advance and optimize the unsafe parameter of the SRAF204, thereby ensuring the safety of inserting the SRAF204 into the layout corresponding to the product and reducing the risk of exposing and developing the SRAF204.
The embodiment of the invention can accurately verify the safety of each parameter of SRAF inserted based on rule_based in different environments in advance and further optimize the SRAF Rule by designing the graph DL_gap_DL with strong optical effect on the SRAF, thereby ensuring the safety of the SRAF inserted in a customer layout and reducing the defects caused by exposing the SRAF.
For a clearer description of embodiments of the present invention, the following are further described with reference to the following parameters:
the line width allowed in the design rule of the line layout is 45nm, and the minimum space period (pitch) is 90nm. The critical layer is subjected to SRAF screening in the earlier stage, the light intensity threshold Ith of the SRAF exposed under the process condition is 0.187203, and the SRAF with the line width of 20nm is screened out when space=140 nm is allowed to be inserted in the space. When the security of SRAF under this condition is verified according to the existing conventional screening SRAF rule layout, the layout is a grating structure of cd=45 nm/pitch=185 nm as shown in fig. 2, and CD is a critical dimension corresponding to the line width W in fig. 2. Pitch corresponds to P in fig. 2; after OPC correction, using an OPC result checking program to simulate a conninur when the light intensity threshold Ith is 0.187203, wherein the conninur is shown in FIG. 6A, the graph in the layout is singly denoted by a mark 101a, the SRAF is singly denoted by a mark 103a, and the simulation graph of the graph 101a in the simulatively formed conninur is singly denoted by a mark 101 b; from the simulation results shown in FIG. 6A, it can be seen that the SRAF is not shown by a conninur, illustrating the security of this addition rule by inserting a 20nm SRAF into the center of the spacer at a space of 140nm in the layout. However, since the pattern structure of space 140nm in the customer layout includes a plurality of patterns, the optical effect of the pattern on the inserted SRAF at the periphery of the space 140nm spacer may be different and may be larger than that of the pattern shown in fig. 2, so that additional development is likely to occur, and thus, debugging is required one by one.
In the embodiment of the invention, a series of Dense line_Gap_Dense lines shown in fig. 5, namely, dense parts of DL_Gap_DL patterns are CD=45 nm, pitch is equal to or less than 90nm and equal to or less than 140nm, gap is equal to or less than 140nm, SRAF with 20nm width is inserted into the Gap center based on rule_based technical patterns, OPC correction is carried out on the series of patterns, and then, an OPC result checking program is utilized to simulate the contur when the light intensity threshold is 0.187203, as shown in fig. 6B, the result is that in fig. 6B, the Dense patterns in the patterns are singly denoted by marks 203a, the SRAF is singly denoted by marks 204a, and the simulation patterns of the Dense patterns 203a in the simulated and formed contur are singly denoted by marks 203B, so that the SRAF is obviously represented by the contur 204B through photoetching simulation from the result; as shown in fig. 7, and it is simulated that the maximum light intensity value Imax > Ith corresponding to SRAF, i.e., corresponding to mark 301, the lower left corner in fig. 7 shows 4 dense patterns and one SRAF, the maximum light intensity value of the 4 dense patterns in the light intensity curve is maximum, and the maximum light intensity value of the SRAF is minimum; from the simulation diagram and the light intensity test structure, the SRAF in the environment has the risk of being exposed under the photoetching process condition, the SRAF needs to be further optimized, the width of the SRAF is reduced to 18nm, and the SRAF safety verification is carried out according to the flow. As shown in fig. 6C, when the SRAF line width is 18nm, the OPC result checking program does not simulate the connur of SRAF, which is denoted by a mark 204C alone in fig. 6C; also, as shown in fig. 7, imax < Ith at this time, that is, the maximum light intensity value corresponding to the optimized SRAF, that is, the maximum light intensity value corresponding to the mark 302 is smaller than Ith, which indicates that the optimized SRAF rule is safe in this environment. The results of security and optimization for the corresponding SRAF for different Pitch conditions are shown in the table of fig. 8. In FIG. 8, like 90nm, the embodiment of the present invention also checks that extra development, SRAF extraprinting, is generated when Pitch, i.e., SRAF with a width of 20nm is inserted at 92nm and 94nm, but the prior art method cannot detect these SRAF with safety problems; SRAF extraprinting is NO when Pitch larger than 94nm is inserted into SRAF, and optimization is not needed; like 90nm, optimization of the parameters of SRAF with P92 nm and 94nm, i.e. width adjustment to 19nm, will not produce additional development, i.e. optimized SRAF extraprinting as NO. Therefore, the method of the embodiment of the invention can accurately verify the safety of the SRAF adding rule in advance, and especially for the complex design of the customer layout, the OPC photomask publishing work can be more efficiently completed by verifying the safety of the exposure auxiliary graph in advance.
The present invention has been described in detail by way of specific examples, but these should not be construed as limiting the invention. Many variations and modifications may be made by one skilled in the art without departing from the principles of the invention, which is also considered to be within the scope of the invention.

Claims (13)

1. A risk prediction and optimization method for SRAF, comprising the steps of:
step one, designing a series of first test pattern structures, wherein each first test pattern structure comprises a first intensive pattern area, a spacing area and a second intensive pattern area, intensive patterns are arranged in the first intensive pattern area and the second intensive pattern area, and the width of the spacing area of each first test pattern structure is gradually changed;
a series of the first test pattern structures are used to simulate different environments in which an SRAF is inserted, the dense patterns are used to enhance the optical impact on the SRAF under different environments;
inserting an SRAF into the interval area of each first test pattern structure and performing OPC correction on each first test pattern structure after the SRAF is inserted;
simulating a simulation contour map of each first test pattern structure by using an OPC result checking program;
fourth, carry on the risk judgement, including:
if the simulated contour diagram does not comprise the contour diagram of the SRAF, the verification result is that each parameter of the SRAF is safe;
if the simulated contour diagram comprises the contour diagram of the SRAF, the verification result is that each parameter of the SRAF is unsafe, and the step five is carried out;
and step five, optimizing the parameters of the SRAF with unsafe parameters, turning to step two, and repeating the steps two to four or the steps two to five until each parameter of each SRAF is safe.
2. The risk prediction and optimization method for SRAF of claim 1, wherein: after the second step and before the fourth step, the method further comprises:
and step six, simulating the maximum light intensity value of the SRAF in each first test pattern structure by using an OPC optical model.
3. The risk prediction and optimization method for SRAF of claim 2, wherein: in the first step, the line width and the space period of the dense pattern are set according to the line width and the minimum space period allowed in the design rule of the corresponding key layer.
4. The risk prediction and optimization method for SRAF of claim 3, wherein: and in the second step, the SRAF is inserted by adopting a rule-based technology.
5. The risk prediction and optimization method for SRAF of claim 4, wherein: the width of the spacer of each first test pattern structure is determined according to the number of inserted SRAFs, and the width of the spacer of each first test pattern structure is gradually changed by gradually changing the number of inserted SRAFs.
6. The risk prediction and optimization method for SRAF of claim 5, wherein: in the first step, the spatial period of the dense pattern is set to be greater than or equal to the minimum spatial period and less than or equal to the first width of the spacer, where the first width is the width of the spacer of the first test pattern structure during the SRAF of 1 inserted.
7. The risk prediction and optimization method for SRAF of claim 5, wherein: in the first test pattern structure, the number of the SRAFs that gradually change in a series of the first test pattern structures is 1 to 6.
8. The risk prediction and optimization method for SRAFs according to claim 5 or 7, wherein: and when a plurality of SRAFs are arranged in the interval area of the first test pattern structure, in the step six, the maximum light intensity value takes the value with the maximum light intensity of all the SRAFs in the interval area of the first test pattern structure.
9. The risk prediction and optimization method for SRAF of claim 1, wherein: and step two, performing OPC correction by adopting an OPC optical model with the process window established.
10. The risk prediction and optimization method for SRAF of claim 9, wherein: and thirdly, simulating and simulating a simulation contour map of each first test pattern structure according to the process window and the light intensity threshold of the OPC model by the OPC result checking program.
11. The risk prediction and optimization method for SRAF of claim 2, wherein: the risk judgment in the fourth step further includes:
comparing the maximum light intensity value of the SRAF in each first test pattern structure with a light intensity threshold value, and if the maximum light intensity value of the SRAF is smaller than the light intensity threshold value, determining that each parameter of the SRAF is safe according to a theoretical determination result;
if the maximum light intensity value of the SRAF is greater than or equal to the light intensity threshold value, the theoretical judgment result is that each parameter of the SRAF is unsafe, and the step five is carried out;
the theoretical judgment result and the verification result complement each other.
12. The risk prediction and optimization method for SRAFs according to claim 10 or 11, wherein: the intensity threshold employs the lowest intensity value required for the earlier verified SRAF to be exposed to develop.
13. The risk prediction and optimization method for SRAF of claim 1, wherein: in step five, optimizing the parameters of the SRAF includes reducing the width of the SRAF.
CN202310113535.9A 2023-02-14 2023-02-14 Risk prediction and optimization method for SRAF (SRAF) Pending CN116184773A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117950281A (en) * 2024-03-19 2024-04-30 全芯智造技术有限公司 Method for detecting auxiliary pattern exposure, electronic device and storage medium

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117950281A (en) * 2024-03-19 2024-04-30 全芯智造技术有限公司 Method for detecting auxiliary pattern exposure, electronic device and storage medium
CN117950281B (en) * 2024-03-19 2024-06-11 全芯智造技术有限公司 Method for detecting auxiliary pattern exposure, electronic device and storage medium

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