CN113050366B - Optical proximity correction method and system, mask, equipment and storage medium - Google Patents

Optical proximity correction method and system, mask, equipment and storage medium Download PDF

Info

Publication number
CN113050366B
CN113050366B CN201911380417.4A CN201911380417A CN113050366B CN 113050366 B CN113050366 B CN 113050366B CN 201911380417 A CN201911380417 A CN 201911380417A CN 113050366 B CN113050366 B CN 113050366B
Authority
CN
China
Prior art keywords
vector
configuration vector
configuration
optimized
focal plane
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201911380417.4A
Other languages
Chinese (zh)
Other versions
CN113050366A (en
Inventor
柏锋
杜杳隽
李甲兮
张婉娟
李亮
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Semiconductor Manufacturing International Shanghai Corp
Semiconductor Manufacturing International Beijing Corp
Original Assignee
Semiconductor Manufacturing International Shanghai Corp
Semiconductor Manufacturing International Beijing Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Semiconductor Manufacturing International Shanghai Corp, Semiconductor Manufacturing International Beijing Corp filed Critical Semiconductor Manufacturing International Shanghai Corp
Priority to CN201911380417.4A priority Critical patent/CN113050366B/en
Publication of CN113050366A publication Critical patent/CN113050366A/en
Application granted granted Critical
Publication of CN113050366B publication Critical patent/CN113050366B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/36—Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

An optical proximity correction method and system, a mask, equipment and a storage medium, wherein the optical proximity correction method comprises the following steps: providing a chip pattern area comprising a plurality of main patterns; providing a corresponding preset auxiliary graph around the main graph, wherein the preset auxiliary graph has a preset width, a preset distance is arranged between the preset auxiliary graph and the corresponding main graph, and the preset distance and the preset width form configuration parameters corresponding to the main graph; obtaining configuration parameters of each main graph, wherein a plurality of corresponding configuration parameters of a plurality of main graphs are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset; optimizing the configuration vector based on the corresponding relation between the configuration vector and the optimal focal plane offset to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset; and setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector. The embodiment of the invention is beneficial to enlarging the common process window of the photoetching process.

Description

Optical proximity correction method and system, mask, equipment and storage medium
Technical Field
The embodiment of the invention relates to the field of semiconductor manufacturing, in particular to an optical proximity correction method and system, a mask, equipment and a storage medium.
Background
Photolithography is a critical technique in semiconductor fabrication that enables transferring patterns from a reticle to a wafer surface to form a semiconductor product that meets design requirements. The photolithography process includes an exposure step, and a development step performed after the exposure step. In the exposure step, light irradiates the silicon wafer coated with the photoresist through a light-transmitting area in the mask plate, and the photoresist is subjected to chemical reaction under the irradiation of the light; in the development step, the difference of the dissolution degree of the photosensitive photoresist and the non-photosensitive photoresist to the developer is utilized to form a photoetching pattern, so that the mask pattern is transferred to the photoresist. After the photolithography process is performed, an etching step is typically further included, that is, the silicon wafer is etched based on the photolithographic pattern formed by the photoresist layer, and the pattern of the reticle is further transferred to the silicon wafer.
In semiconductor manufacturing, as the design size is continuously reduced, the design size is more and more close to the limit of a photoetching imaging system, the diffraction effect of light becomes more and more obvious, optical image degradation is finally generated on a design pattern, the actually formed photoetching pattern is severely distorted relative to the pattern on a mask plate, and finally the actual pattern formed by photoetching on a silicon wafer is different from the design pattern, and the phenomenon is called optical proximity effect (OPE: optical Proximity Effect). Sub-resolution assist feature (Sub-Resolution Assist Features), optical proximity correction (Optical Proximity Correction, OPC for short), reverse lithography (Inverse Lithography Technology, ILT for short), dual feature (Double Patterning), self-aligned dual feature (Self-aligned Double Patterning) and other techniques are used to improve lithography resolution.
The scattering bar (SCATTERING BAR, SB) is a sub-resolution auxiliary pattern, which uses auxiliary pattern bars around the Main pattern (Main Feature) to improve the lithography quality of the Main pattern. Wherein the primary pattern is an exposable pattern and the scattering bars are typically non-exposable patterns.
Disclosure of Invention
The embodiment of the invention solves the problem of providing an optical proximity correction method and system, a mask, equipment and a storage medium, and the common process window of a photoetching process is increased.
In order to solve the above-mentioned problems, an embodiment of the present invention provides an optical proximity correction method, including: providing a chip pattern area, wherein the chip pattern area comprises a plurality of main patterns; providing a corresponding preset auxiliary graph around the main graph, wherein the preset auxiliary graph has a preset width, a preset distance is arranged between the preset auxiliary graph and the corresponding main graph, and the preset distance and the preset width form configuration parameters corresponding to the main graph; obtaining configuration parameters of each main graph, wherein a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset; based on the corresponding relation between the configuration vector and the optimal focal plane offset, carrying out optimization processing on the configuration vector to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset; and setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector.
Correspondingly, the embodiment of the invention also provides an optical proximity correction system, which comprises: a main pattern providing unit for providing a chip pattern area including a plurality of main patterns; the preset unit is used for providing corresponding preset auxiliary graphics around the main graphics, the preset auxiliary graphics have preset widths, preset distances are arranged between the preset auxiliary graphics and the corresponding main graphics, and the preset distances and the preset widths form configuration parameters corresponding to the main graphics; the acquisition unit is used for acquiring configuration parameters of each main graph, and a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, wherein the configuration vector has a corresponding relation with the optimal focal plane offset; the optimization processing unit is used for carrying out optimization processing on the configuration vector based on the corresponding relation between the configuration vector and the optimal focal plane offset to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset; and the configuration unit is used for setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector.
Correspondingly, the embodiment of the invention also provides a mask plate, which comprises the following steps: a plurality of main patterns and auxiliary patterns positioned around the main patterns, wherein the auxiliary patterns are arranged by the optical proximity correction method.
Accordingly, an embodiment of the present invention also provides an apparatus, including at least one memory and at least one processor, where the memory stores one or more computer instructions, and where the one or more computer instructions are executed by the processor to implement the foregoing optical proximity correction method.
Correspondingly, the embodiment of the invention also provides a storage medium, wherein one or more computer instructions are stored in the storage medium, and the one or more computer instructions are used for realizing the optical proximity correction method.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:
In the optical proximity correction method provided by the embodiment of the invention, a corresponding preset auxiliary graph is provided around the main graph, configuration parameters of each main graph are obtained, a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, the configuration vector has a corresponding relation with the optimal focal plane offset, then the configuration vector is optimized based on the corresponding relation between the configuration vector and the optimal focal plane offset (Best focus shift, BFS), an optimized configuration vector corresponding to the minimum optimal focal plane offset is obtained, and then the auxiliary graph is arranged around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vector, so that the optimal focal plane offset between different types of main graphs is smaller after the auxiliary graph is arranged around the main graph, that is, the optimal focal planes (Best focus) corresponding to the different types of main graphs are closer, the focus depth overlapping part between the different types of main graphs is maximized, and the common process window (Common process window) of the maximized photoetching process is facilitated.
Drawings
FIG. 1 is a flow chart of an embodiment of an optical proximity correction method of the present invention;
FIG. 2 is a flowchart of an embodiment of step S4 in FIG. 1;
FIG. 3 is a flowchart of an embodiment of step S42 in FIG. 2;
Fig. 4 to 6 are schematic diagrams of the preset auxiliary pattern provided in step S2 in fig. 1;
FIG. 7 is a functional block diagram of one embodiment of an optical proximity correction system of the present invention;
fig. 8 is a hardware configuration diagram of an apparatus according to an embodiment of the present invention.
Detailed Description
As known from the background art, setting sub-resolution auxiliary patterns around the main pattern of the mask is one of the common resolution enhancement techniques to improve the lithography quality of the main pattern.
However, the current method of setting sub-resolution auxiliary patterns can result in larger Best focus offset (BFS) between different types of main patterns (MAIN PATTERN), and smaller overlapping portions of different types of focus depths, which can reduce the photolithography common process window of the whole mask. The sub-resolution auxiliary pattern is exemplified as a scattering bar (SCATTERING BARS) below.
The current method for setting the scattering bars comprises an auxiliary pattern (Rules-based SRAF) setting method based on an empirical rule, wherein the method sets the scattering bars around the main pattern based on the empirical rule, i.e. according to the empirical manual preset configuration rule, the width of the scattering bars and the distance from the scattering bars to the main pattern are adjusted by combining the information such as the characteristic size, the spacing and the like of the main pattern.
Still another method is a model-based auxiliary pattern setting method, which simulates the actual exposure result according to the size and the inserted position of the scattering bars, and then continuously adjusts these parameters to make the main pattern reach the optimal focus plane and the maximum depth of focus. Or based on past experience and data information of the main pattern on the wafer, the scattering bars are directly arranged on the mask.
However, the above methods are all aimed at the local main pattern reaching the best focus plane and the maximum depth of focus, to set the position and size of the scattering bars. For example: the above method is to set scattering bars around the main pattern according to the feature size and the spacing of each type of main pattern, so as to make the local main pattern reach the best focusing plane and the maximum focal depth. After the scattering bars are added according to the method, the scattering bars easily affect the common focal depth of the lithography process, that is, the scattering bars easily cause the overlapping part of the focal depths of the main patterns of different types to be smaller, and the Best focus plane offset (Best focus shift) between the main patterns of different types is larger, so that the lithography common process window of the whole layout is reduced.
In order to solve the technical problem, in the optical proximity correction method provided by the embodiment of the invention, a corresponding preset auxiliary graph is provided around the main graph, and configuration parameters of each main graph are obtained, a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, the configuration vector has a corresponding relation with an optimal focal plane offset, then, based on the corresponding relation between the configuration vector and the optimal focal plane offset, the configuration vector is optimized to obtain an optimized configuration vector corresponding to the smallest optimal focal plane offset, and then, auxiliary graphs are arranged around the main graph according to the plurality of configuration parameters corresponding to the optimized configuration vector, so that after the auxiliary graph is arranged around the main graph, the optimal focal plane offset between different types of main graphs is smaller, that is, the optimal focal plane (Best focus) corresponding to the different types of main graphs is closer, and the focal depth overlapping part between the different types of main graphs is maximized, thereby being beneficial to obtaining a common process window of the maximized photolithography process.
Referring to FIG. 1, a flow chart of an embodiment of the optical proximity correction method of the present invention is shown. Referring in conjunction to FIG. 2, a flow chart of one embodiment of step S4 in FIG. 1 is shown. Referring in conjunction to FIG. 3, a flow chart of one embodiment of step S42 in FIG. 2 is shown. As an example, the optical proximity correction method of the present embodiment includes the following basic steps:
step S1: providing a chip pattern area, wherein the chip pattern area comprises a plurality of main patterns;
Step S2: providing a preset auxiliary graph corresponding to the preset auxiliary graph around the main graph, wherein the preset auxiliary graph has a preset width, a preset distance is arranged between the preset auxiliary graph and the corresponding main graph, and the preset distance and the preset width form configuration parameters corresponding to the main graph;
Step S3: obtaining configuration parameters of each main graph, wherein a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset;
Step S4: based on the corresponding relation between the configuration vector and the optimal focal plane offset, carrying out optimization processing on the configuration vector to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset;
step S5: and setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector.
In order that the above objects, features and advantages of embodiments of the invention may be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
Referring to fig. 1 in combination, step S1 is performed to provide a chip pattern area including a plurality of main patterns.
The chip pattern area is used for manufacturing a mask plate used in the photoetching process of the chip, the mask plate is used as a mask plate to expose photoresist on the wafer so as to form photoresist patterns of all chip areas on the wafer, and the photoresist patterns can be used for etching the chip areas of the wafer and forming semiconductor structures such as grid electrodes, metal interconnection lines or conductive plugs in the chip areas of the wafer. The wafer comprises a plurality of chip areas which are arranged in an array, and cutting channels are arranged between the adjacent chip areas.
The main pattern is an exposable pattern used for defining a photoresist pattern formed by exposure, and the size of the main pattern is larger than the resolution critical value of the photoetching process. The main pattern includes a long stripe pattern, a rectangular pattern, or a square pattern.
Each of the main patterns has a target feature size (CD) and a target pitch (pitch), and the target feature sizes and the target pitches of the plurality of types of main patterns are different. The shapes of the various main patterns are also different.
Referring to fig. 4,5 and 6 in combination, wherein fig. 4b is a partial enlarged view of fig. 4a, fig. 5b is a partial enlarged view of fig. 5a, and fig. 6b is a partial enlarged view of fig. 6a, respectively showing three main patterns having different types of target feature sizes and target pitches in the present embodiment: a first main pattern A1, a second main pattern A2, and a third main pattern A3.
As an example, in this embodiment, the first main pattern A1 is a rectangular pattern, the second main pattern A2 is a rectangular pattern, and the third main pattern A3 is a square pattern.
With continued reference to fig. 1, step S2 is performed to provide a corresponding preset auxiliary pattern around the main pattern; the preset auxiliary graph has a preset width w, a preset distance d is arranged between the preset auxiliary graph and the corresponding main graph, and the preset distance d and the preset width w form configuration parameters (d, w) corresponding to the main graph.
And the preset auxiliary graph is used for preparing an optimal configuration vector for the subsequent optimization processing.
In this embodiment, the auxiliary pattern includes scattering bars. The scattering bars (SCATTERING BAR, SB) are a sub-resolution assist feature. The arrangement of the scattering bars has the following advantages: firstly, the outline linewidth of the photoetching pattern can be sensed, the light intensity contrast is improved, and the edge placement Error (EDGE PLACEMENT Error) is reduced; second, the depth of focus is increased, thereby improving the lithography process window.
With continued reference to fig. 1, step S3 is performed to obtain configuration parameters of each of the main patterns, where the configuration parameters (D, w) of the plurality of main patterns are used to form a configuration vector D, and the configuration vector D has a corresponding relationship with the best focal plane offset.
In this embodiment, the configuration vector D is composed of configuration parameters (D, w) of various main graphics, and the configuration vector D may be represented by formula (i):
D＝(d1,w1,d2,w2,……,dN,wN) (Ⅰ)
Where N refers to the main pattern having the nth feature size and pitch. In this embodiment, the configuration vector D is a high-dimensional vector, and the configuration vector D is used as an object of the subsequent optimization process.
Referring to fig. 4, 5 and 6 in combination, the provision of the main pattern and the corresponding preset auxiliary pattern in this embodiment is illustrated. In this embodiment, a first preset auxiliary pattern B1 is disposed around the first main pattern A1, a second preset auxiliary pattern B2 is disposed around the second main pattern A2, and a third preset auxiliary pattern B3 is disposed around the third main pattern A3, respectively.
The first preset auxiliary graph B1 has a preset distance d1 and a preset width w1, the second preset auxiliary graph B2 has a preset distance d2 and a preset width w2, and the third preset auxiliary graph B3 has a preset distance d3 and a preset width w3.
Accordingly, in this embodiment, the configuration vector D may be as shown in formula (ii):
D＝(d1,w1,d2,w2,d3,w3) (Ⅱ)
The configuration vector D has a correspondence with a best focus plane offset (BFS). Specifically, the configuration vector D has a correspondence relationship with the optimal focal plane offset (BFS) between the plurality of main patterns.
Each primary pattern has a corresponding best focus plane. The best focal plane offset refers to: and for a plurality of optimal focal planes respectively corresponding to the plurality of main patterns, obtaining the maximum value and the minimum value in a plurality of optimal focal plane values, wherein the difference value between the maximum value and the minimum value is the optimal focal plane offset among the plurality of main patterns, namely the optimal focal plane offset.
After providing a corresponding preset auxiliary pattern around the main pattern, the optimal focal plane offset is a function F (D) of the configuration vector. Specifically, there is a mapping relationship between the best focal plane offset and the configuration vector D, that is, when assigning a plurality of configuration parameters corresponding to the configuration vector D, for each configuration vector D, there is a uniquely determined best focal plane offset corresponding to the configuration vector D according to a certain determined rule F.
In this embodiment, by using a plurality of configuration parameters (D, w) corresponding to a plurality of main patterns to form a configuration vector D, where the configuration vector D is used as an argument, and a function F (D) of an optimal focal plane offset is used as an objective function of a subsequent optimization process, an optimal focal plane of the plurality of main patterns during photolithography can be considered, and when the optimal configuration vector is obtained after the subsequent optimization process, the optimal focal plane offset between the plurality of main patterns can be minimized, thereby obtaining a common process window of the maximized photolithography process.
Specifically, the smaller the offset of the best focal plane between the different kinds of main patterns, the closer the best focal plane of the different kinds of main patterns is, the larger the common focal depth between the different kinds of main patterns is correspondingly, and accordingly, the larger the common process window of photolithography is.
In an actual process, for each of the configuration vectors D, the step of obtaining a corresponding best focus plane offset may include: on the basis of the configuration vector D, respectively obtaining optimal focal planes corresponding to each type of main graph, and obtaining a plurality of optimal focal planes; maximum and minimum values of a plurality of best focal planes are obtained, and the minimum value is subtracted from the maximum value as the best focal plane offset. Wherein, the optimal focal plane corresponding to each type of main graph can be obtained by an optical simulation mode.
With continued reference to fig. 1, step S4 is executed to perform an optimization process on the configuration vector D based on the correspondence between the configuration vector D and the optimal focal plane offset (BFS), so as to obtain an optimized configuration vector D opt corresponding to the smallest optimal focal plane offset.
The configuration vector D is optimized based on the correspondence between the configuration vector D and the optimal focal plane offset (BFS), so as to obtain an optimized configuration vector D opt corresponding to the minimum optimal focal plane offset, so that an auxiliary pattern can be set around the main pattern according to a plurality of configuration parameters corresponding to the optimized configuration vector D opt, which is beneficial to ensuring that the optimal focal plane offset (BFS) between different types of main patterns in the photolithography process is smaller, that is, the optimal focal planes between different types of main patterns are closer, so that the focal depth overlapping portion between different types of main patterns is maximized, and a common process window (Common process window) of the maximized photolithography process is beneficial to being obtained.
In this embodiment, a numerical optimizer (numerical optimizer) is used to optimize the configuration vector D. In this embodiment, a gradient algorithm may be used to perform optimization processing on the configuration vector D.
In this embodiment, the step of optimizing the configuration vector D by using a gradient algorithm includes: and (3) obtaining a corresponding optimal configuration vector D opt by adopting a gradient algorithm, wherein the partial derivative of the function F (D) of the optimal focal plane offset with respect to the configuration vector D is zero. That is, a gradient algorithm is used to obtain the optimal focal plane offset BFS as a function F (D) with respect to the configuration vector D, the gradient vector being zero, the corresponding optimal configuration vector D opt.
When the partial derivative of the function F (D) of the optimum focal plane offset with respect to the configuration vector D is zero, the optimum focal plane offset BFS accordingly converges, that is, the optimum focal plane offset BFS accordingly attains a minimum value.
Specifically, in the actual operation, a gradient algorithm is adopted to obtain a gradient vector of the function F (D) of the optimal focal plane offset with respect to the configuration vector D, and a difference value between the gradient vector and zero is within a preset Threshold (Threshold), so as to correspondingly optimize the configuration vector D opt.
The preset threshold range is not too small nor too large. If the preset threshold range is too small, the optimization processing speed is too slow, and the optimization processing efficiency is easy to be reduced; if the preset threshold range is too large, it is easy to cause incomplete optimization, for example: the optimal focal plane offset corresponding to the optimal configuration vector obtained after the optimization process may not be the minimum value. For this reason, in the present embodiment, the preset threshold range is 10 -5 to 10 -1, for example: the preset threshold range is 0.001,0.0001, etc.
Referring to fig. 1 and 2 in combination, fig. 2 is a flowchart of an embodiment of step S4 in fig. 1, where the step of performing the optimization process on the configuration vector D includes:
Step S41 is executed, and an initial configuration vector D 0 is set, and the initial configuration vector D 0 is used as a configuration vector D i to be optimized;
Step S42 is executed to search along the direction of the gradient vector corresponding to the configuration vector D i to be optimized, and obtain the optimized configuration vector D opt corresponding to the smallest best focal plane offset.
As an example, the specific steps of the optimization process for the configuration vector D in the present embodiment will be described in detail with reference to the accompanying drawings.
Step S41 is performed to set an initial configuration vector D 0, and the initial configuration vector D 0 is used as the configuration vector D i to be optimized. By setting the initial configuration vector D 0 as the configuration vector D i to be optimized, preparation is made for subsequent searches along the gradient vector direction corresponding to the configuration vector D i to be optimized.
The configuration vector D i to be optimized may be the initial configuration vector D 0, or may be the configuration vector D i to be optimized in the subsequent searching process.
In this embodiment, the configuration vector D i to be optimized is determined by the formula (iv):
Di＝(di,1,wi,1,di,2,wi,2,……,di,N,wi,N) (Ⅳ)
Wherein i is a positive integer from 0 to N. When i=0, the configuration vector D i to be optimized is the initial configuration vector D 0.
Step S42 is executed to search along the direction of the gradient vector corresponding to the configuration vector D i to be optimized, and obtain the optimized configuration vector D opt corresponding to the smallest best focal plane offset.
Specifically, in this embodiment, an optimal configuration vector D opt corresponding to the difference between the gradient vector and zero in the foregoing preset threshold range is obtained.
In this embodiment, by the steepest descent method, the optimal configuration vector D opt corresponding to the smallest optimal focal plane offset is obtained by searching along the direction of the gradient vector corresponding to the configuration vector D i to be optimized. The steepest descent method descends along the negative gradient direction, so that when the optimal configuration vector D opt corresponding to the difference between the gradient vector and zero in the preset threshold range is obtained, the minimum optimal focal plane offset BFS corresponding to the optimal configuration vector D opt is correspondingly obtained.
In other embodiments, a conjugate gradient method or other search algorithm may be used to search along the direction of the gradient vector, so as to obtain an optimal configuration vector corresponding to zero gradient vector.
Referring to fig. 3 in combination, fig. 3 is a flowchart of an embodiment of step S42 in fig. 2, in this embodiment, the step of searching along the direction of the gradient vector corresponding to the configuration vector D i to be optimized, and obtaining the optimized configuration vector D opt corresponding to the smallest best focal plane offset includes:
Step S421 is executed, where a variation Δd i is set for the configuration vector D i to be optimized, and a gradient vector of the best focal plane offset with respect to the configuration vector D i to be optimized is obtained according to the variation Δd i.
Provision is made for obtaining the gradient vector of the best focal plane offset with respect to the configuration vector D i to be optimized by setting a variation Δd i to the configuration vector D i to be optimized.
In this embodiment, the step of setting a variation Δd i for the configuration vector D i to be optimized includes: on the basis of a plurality of configuration parameters corresponding to the configuration vector D i to be optimized, setting a distance offset Deltad for a plurality of preset distances D, setting a width offset Deltaw for a plurality of preset widths w, and forming the variation DeltaD i by the plurality of distance offsets Deltad and the plurality of width offsets Deltaw.
In this embodiment, a finite difference method is used to obtain a gradient vector of the function F (D) of the optimum focal plane offset with respect to the configuration vector D i to be optimized. The finite difference method is a numerical solution, the finite difference method replaces partial derivatives with difference quotient in differential equations to obtain corresponding differential equations, and an approximation of differential equation solution is obtained by solving the differential equations.
In this embodiment, the step of obtaining the gradient vector of the optimal focal plane offset function F (D) with respect to the configuration vector D i to be optimized includes: setting a variation delta D i for the configuration vector D i to be optimized, and obtaining a variation delta F (D) of the optimal focal plane offset corresponding to the variation delta D i; dividing the variation DeltaF (D) of the optimal focal plane offset by the variation DeltaD to obtain a gradient vector corresponding to the configuration vector D i to be optimized
The plurality of predetermined distances D and the predetermined widths w each form a component of the configuration vector D, that is to say the configuration vector D has a plurality of components (D 1,w1,d2,w2,……,dN,wN).
Specifically, in this embodiment, the step of obtaining the gradient vector of the optimal focal plane offset with respect to the configuration vector D i to be optimized includes: and respectively calculating partial derivatives of the optimal focal plane offset with respect to each component on the basis of a configuration vector D i to be optimized and a variation delta D i, wherein the partial derivatives are used as gradient components in the corresponding direction of each component, and a plurality of gradient components in the corresponding directions of a plurality of components form the gradient vector.
Under a plurality of different components of the configuration vector D i to be optimized, setting an offset for each component respectively; and then, respectively carrying out partial derivative calculation on each component to obtain partial derivatives corresponding to a plurality of components, wherein the partial derivative corresponding to each component is used as a gradient component, and the gradient components in the directions corresponding to the components form the gradient vector.
As an example, the step of obtaining the gradient component corresponding to the component d1 may be as follows:
Firstly, on the basis of a d1 component, under the condition that other components are unchanged, obtaining an optimal focal plane offset F1 corresponding to the d1 component; then, a distance offset Δd is set on the basis of the d1 component, that is, d1 is changed to d1+ [ delta ] d; then, on the basis of d1+ [ delta ] d, obtaining an optimal focal plane offset F2 corresponding to d1+ [ delta ] d, and subtracting an optimal focal plane offset F1 corresponding to d1 component from the optimal focal plane offset F2 corresponding to d1+ [ delta ] d to obtain a variation delta [ F d1 ] of the optimal focal plane offset; and calculating a gradient component (namely a partial derivative component) in the direction corresponding to the d1 component according to the variation delta F d1 of the optimal focal plane offset and the distance offset delta d.
The other components remain unchanged when the gradient component corresponding to one component is calculated.
Wherein the step of obtaining the optimal focal plane offset comprises: firstly, respectively obtaining optimal focal planes corresponding to each type of main graph, and obtaining a plurality of optimal focal planes; maximum and minimum values of the plurality of best focal planes are obtained, and the maximum value is used for subtracting the minimum value to obtain the best focal plane offset.
Specifically, the gradient component in the direction corresponding to the d1 component is obtained by calculating the quotient of the variation Δf d1 of the optimum focal plane offset and the distance offset Δd.
Repeating the steps, respectively calculating gradient components in the corresponding directions of the components for the components of the configuration vector D, wherein the gradient components form the gradient vector.
Step S422 is executed to determine whether the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset Threshold (Threshold); when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset threshold range, executing step S423 to complete the optimization process, and taking the configuration vector D i to be optimized as the optimization configuration vector D opt; when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is not within the preset threshold range, step S424 is executed to update the configuration vector to be optimized according to the variation Δd i.
In this embodiment, the step of determining whether the difference between the gradient vector corresponding to the configuration vector D opt to be optimized and zero is within the preset threshold range includes: respectively judging whether the difference values between a plurality of gradient components of the gradient vector and zero are all within a preset threshold range; when the difference values between the gradient components and zero of the gradient vector are all within a preset threshold value range, finishing optimization processing; and when the difference value between at least one component in the gradient vector and zero is not in a threshold value range, updating the configuration vector D i to be optimized according to the variation delta D i.
And when the quotient of the variation of the best focal plane offset and the variation is zero, the minimum value of the best focal plane offset and the corresponding optimal configuration vector are correspondingly obtained as shown in a formula (V).
In actual operation, when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset threshold range, the function F (D) of the optimal focal plane offset (BFS) converges, and correspondingly, the minimum value of the optimal focal plane offset is also obtained, so that step S423 can be executed to complete the optimization process.
When the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is not within the preset threshold, it is indicated that the best focal plane offset corresponding to the configuration vector D i to be optimized does not reach the minimum value, and therefore step S424 is required to be performed, and the configuration vector D i to be optimized is updated according to the variation Δd i.
And updating the configuration vector D i to be optimized according to the variation DeltaD i, so as to return to the execution of step S421, namely, continuing to search along the direction of the gradient vector corresponding to the configuration vector D i to be optimized until the corresponding optimized configuration vector D opt is obtained when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset threshold range.
In this embodiment, the step S424 is executed, and the step of updating the configuration vector to be optimized according to the variation Δd i includes: and obtaining an updated configuration vector D i+1 according to the configuration vector D i to be optimized and the variation delta D i, and replacing the configuration vector D i to be optimized with the updated configuration vector D i+1. Specifically, the update configuration vector D i+1 is obtained by adding the variation Δd i to the configuration vector D i to be optimized.
In this embodiment, the configuration vector D i in the search along the direction of the gradient vector is determined by the aforementioned formula (iv). When i=n, the N-th update of the configuration vector to be optimized is indicated, that is, after the last optimization, the obtained optimized configuration vector D opt is obtained. That is, if the optimum focal plane offset between the different kinds of main patterns is converged from i to n+1, it is interpreted that the optimum focal plane offset between the different kinds of main patterns reaches the minimum value, and the optimization process is completed.
As shown in table 1, a plurality of configuration parameters corresponding to the optimized configuration vector D opt obtained in the present embodiment are shown. Wherein, the pitch (pitch) of the first behavior master pattern in table 1 (unit: nm), the first column being the feature size (CD) (unit: nm) of the main pattern, configuration parameters corresponding to the pitch and feature size are shown in the other cells in table 1, for example: for a main pattern with a feature size of 50nm and a pitch of 140nm, the corresponding configuration parameters are (60, 20), that is to say the distance from the auxiliary pattern to the main pattern is 60nm and the linewidth of the auxiliary pattern is 20nm.
TABLE 1
With continued reference to fig. 1, step S5 is performed, where an auxiliary graph is set around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vector D opt.
The optimal configuration vector D opt corresponds to the minimum optimal focal plane offset or corresponds to the maximum common focal depth, so that after the auxiliary patterns are set around the main patterns according to the configuration parameters corresponding to the optimal configuration vector D opt, the optimal focal planes between the different main patterns are closer during lithography, that is, the optimal focal plane offset (BFS) between the different types of main patterns is smaller, and the common focal depth between the different types of main patterns is larger, thereby being beneficial to enlarging the common process window of the lithography process.
Specifically, the auxiliary pattern may be set around the main pattern according to the configuration parameters in the table 1.
Correspondingly, the invention further provides an optical proximity correction system. Referring to fig. 7, a functional block diagram of one embodiment of an optical proximity correction system of the present invention is shown.
The optical proximity correction system includes: a main pattern providing unit U1 for providing a chip pattern area including a plurality of main patterns; a preset unit U2, configured to provide a corresponding preset auxiliary pattern around the main pattern, where the preset auxiliary pattern has a preset width w, a preset distance s is between the preset auxiliary pattern and the corresponding main pattern, and the preset distance d and the preset width w form a configuration parameter (d, w) corresponding to the main pattern; an obtaining unit U3, configured to obtain configuration parameters (D, w) of each main pattern, where a plurality of configuration parameters corresponding to a plurality of main patterns are used to form a configuration vector D, and the configuration vector D has a corresponding relationship with an optimal focal plane offset; an optimization processing unit U4, configured to perform optimization processing on the configuration vector D based on the correspondence between the configuration vector D and the optimal focal plane offset, to obtain an optimized configuration vector D opt corresponding to the minimum optimal focal plane offset; and the configuration unit U5 is used for setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector D opt.
The chip pattern area provided by the main pattern providing unit U1 is used for manufacturing a mask plate used in a chip photoetching process, the mask plate is used as a mask to expose photoresist on a wafer so as to form photoresist patterns of all chip areas on the wafer, and the photoresist patterns can be used for etching the chip areas of the wafer so as to form semiconductor structures such as a grid electrode, a metal interconnection line or a conductive plug in the chip areas of the wafer.
The wafer comprises a plurality of chip areas which are arranged in an array, and cutting channels are arranged between the adjacent chip areas. The main pattern is an exposable pattern used for defining a photoresist pattern formed by exposure, and the size of the main pattern is larger than the resolution critical value of the photoetching process.
The main pattern comprises a strip pattern, a rectangular pattern or a square pattern.
Each of the main patterns has a target feature size (CD) and a target pitch (pitch), and the target feature sizes and the target pitches of the plurality of types of main patterns are different. The shapes of the various main patterns are also different.
The preset unit U2 is configured to provide a preset auxiliary graph and provide configuration parameters corresponding to the main graph, so as to prepare for the obtaining unit to obtain the configuration parameters of each main graph.
In this embodiment, the auxiliary pattern includes scattering bars. The scattering bar is a sub-resolution auxiliary pattern. The arrangement of the scattering bars has the following advantages: firstly, the outline linewidth of the photoetching pattern can be sensed, the light intensity contrast is improved, and the edge placement error is reduced; second, the depth of focus is increased, thereby improving the lithography process window.
The obtaining unit U3 is configured to obtain the configuration vector D, thereby preparing for the optimization processing unit U4 to obtain an optimized configuration vector.
In the present embodiment, the configuration vector D is constituted by the configuration parameters (D, w) of the plurality of main patterns, and therefore, the configuration vector D is represented by the formula (i) in the foregoing embodiment. In this embodiment, the configuration vector D is a high-dimensional vector, and the configuration vector D is used as an object of the subsequent optimization process.
After obtaining the configuration vector D, the obtaining unit U3 has a correspondence relationship between the configuration vector D and the best focal plane offset. Specifically, the configuration vector D has a correspondence relationship with the optimal focal plane offset amounts between the plurality of main patterns.
Each primary pattern has a corresponding best focus plane. The best focal plane offset refers to: for a plurality of best focal planes respectively corresponding to the plurality of main patterns, the difference between the maximum value and the minimum value in the plurality of best focal planes is the best focal plane offset between the plurality of main patterns, namely the best focal plane offset.
The best focal plane offset is a function F (D) of the configuration vector D. Specifically, there is a mapping relationship between the best focal plane offset and the configuration vectors D, that is, when assigning values to the configuration vectors D, for each configuration vector D, there is a uniquely determined best focal plane offset corresponding to the configuration vector D according to a certain determined rule F.
In this embodiment, the obtaining unit U3 obtains a plurality of configuration parameters (D, w) corresponding to a plurality of main patterns to form a configuration vector D, where the configuration vector D is used as an argument, and the function F (D) of the optimal focal plane offset is used as an objective function of the subsequent optimization processing, so that the optimal focal planes of the plurality of main patterns during lithography can be considered, and when the optimal configuration vector is obtained after the subsequent optimization processing, the optimal focal plane offset between the plurality of main patterns can be correspondingly minimized, thereby obtaining a common process window of the maximized lithography process.
Specifically, the smaller the optimum focal plane offset between the different kinds of main patterns, the closer the optimum focal planes of the different kinds of main patterns are, and accordingly, the larger the common focal depth between the different kinds of main patterns is, the larger the common process window for photolithography is.
The optimization processing unit U4 performs optimization processing on the configuration vector D based on the correspondence between the configuration vector D and the optimal focal plane offset, to obtain an optimized configuration vector D opt corresponding to the minimum optimal focal plane offset.
The optimization processing unit U4 is configured to perform optimization processing on the configuration vector D to obtain an optimized configuration vector D opt, so that data of the optimized configuration vector D opt is output to the configuration unit U5.
The optimizing processing unit U4 obtains the optimal configuration vector D opt corresponding to the minimum optimal focal plane offset, so that an auxiliary graph is set around the main graph in the configuration unit U5 according to the configuration parameter corresponding to the optimal configuration vector D opt, which is beneficial to ensuring that the optimal focal plane offset between different types of main graphs is smaller and the optimal focal plane between different types of main graphs is closer when the auxiliary graph is set, and correspondingly, the common focal depth between different types of main graphs is larger, thereby being beneficial to obtaining the common process window of the maximized photolithography process.
In this embodiment, the optimization processing unit U4 is configured to perform optimization processing on the configuration vector D by using a gradient algorithm. In this embodiment, the optimization processing unit U4 is configured to obtain, by using a gradient algorithm, a corresponding optimized configuration vector D opt when the partial derivative of the function F (D) of the optimal focal plane offset with respect to the configuration vector D is zero. That is, the function F (D) of the optimal focal plane offset BFS obtained by the gradient algorithm is zero with respect to the gradient vector of the configuration vector D, and the corresponding optimal configuration vector D opt (as shown by the formula (iii) in the foregoing embodiment).
When the partial derivative of the function F (D) of the optimum focal plane offset with respect to the configuration vector D is zero, the function F (D) of the optimum focal plane offset accordingly converges, that is, the optimum focal plane offset D accordingly attains a minimum value.
Specifically, in actual operation, the optimization processing unit U4 is configured to obtain, by using a gradient algorithm, a gradient vector of the function F (D) of the optimal focal plane offset with respect to the configuration vector D, and a difference value between the gradient vector and zero is within a preset Threshold (Threshold), which corresponds to the optimal configuration vector D opt.
The preset threshold range is not too small nor too large. If the preset threshold range is too small, the speed of optimizing the processing unit U4 is too slow, and the processing efficiency of the optimizing unit U4 is easy to be reduced; if the preset threshold range is too large, the optimization processing unit U4 is liable to not perform the optimization process thoroughly, for example: the optimum focal plane offset corresponding to the optimum configuration vector obtained by the optimum processing unit U4 may not be the minimum value. For this reason, in the present embodiment, the preset threshold range is 10 -5 to 10 -1, for example: the preset threshold range is 0.001,0.0001, etc.
In this embodiment, the optimization processing unit U4 includes: an initial setting unit U41, configured to set an initial configuration vector D 0, and use the initial configuration vector D 0 as a configuration vector D i to be optimized; and a searching unit U42, configured to search along the direction of the gradient vector corresponding to the configuration vector to be optimized, and obtain an optimized configuration vector D opt corresponding to the smallest optimal focal plane offset.
The initial setting unit U41 is used for preparing for searching by the searching unit U42 along the gradient vector direction corresponding to the configuration vector D i to be optimized.
The configuration vector D i to be optimized may be the initial configuration vector D 0, or may be the configuration vector D i to be optimized in the subsequent searching process.
In this embodiment, the configuration vector D i to be optimized is determined by the formula (iv) in the foregoing embodiment. Wherein i is a positive integer from 0 to N. When i=0, the configuration vector D i to be optimized is the initial configuration vector D 0.
The searching unit U42 is configured to search along a direction of a gradient vector corresponding to the configuration vector D i to be optimized, and obtain an optimized configuration vector D opt corresponding to the smallest optimal focal plane offset.
Specifically, in this embodiment, the search unit U42 is configured to obtain an optimal configuration vector D opt corresponding to a case where the difference between the gradient vector and zero is within the foregoing preset threshold range.
In this embodiment, the search unit U42 is configured to search along the direction of the gradient vector corresponding to the configuration vector to be optimized by using the steepest descent method, so as to obtain the optimized configuration vector D opt corresponding to the smallest optimal focal plane offset. The steepest descent method descends along the negative gradient direction, so that when the optimal configuration vector D opt corresponding to the difference value between the gradient vector and zero in the preset threshold range is obtained, the minimum optimal focal plane offset corresponding to the optimal configuration vector D opt is correspondingly obtained.
In other embodiments, the searching unit is further configured to search along the direction of the gradient vector by using a conjugate gradient method or other searching algorithms, so as to obtain an optimal configuration vector corresponding to zero gradient vector.
In this embodiment, the search unit U42 includes: a calculating subunit U421, configured to set a variation Δd i for the configuration vector D i to be optimized, and obtain a gradient vector of the best focal plane offset with respect to the configuration vector D i to be optimized according to the variation Δd i; a judging subunit U422, configured to judge whether the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within a preset Threshold (Threshold); when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset threshold range, the judging subunit U422 is configured to output the configuration vector D i to be optimized to the completing subunit U423, where the completing subunit U423 is configured to take the configuration vector D i to be optimized as the optimized configuration vector D opt; when the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is not within the preset threshold range, the determining subunit U422 is configured to output the configuration vector to be optimized to the returning subunit U424, and the returning subunit U424 is configured to update the configuration vector D i to be optimized according to the variation Δd i and return to the calculating subunit U421.
In this embodiment, the calculating subunit U421 is configured to obtain the gradient vector by using a finite difference method.
In this embodiment, after setting a variation Δd i for the configuration vector D i to be optimized, the computing subunit U421 is configured to obtain a variation Δf (D) of the best focal plane offset corresponding to the variation Δd i, and divide the variation Δf (D) of the best focal plane offset by the variation Δd to obtain a gradient vector corresponding to the configuration vector D i to be optimized
The plurality of predetermined distances D and the predetermined widths w each form a component of the configuration vector D, that is to say the configuration vector D has a plurality of components (D 1,w1,d2,w2,……,dN,wN).
Specifically, the calculating subunit U421 is configured to calculate partial derivatives of the best focal plane offset with respect to each of the components, as gradient components in each component corresponding direction, and a plurality of gradient components in a plurality of component corresponding directions constitute the gradient vector.
The judging subunit U422 is configured to judge whether the difference between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold range.
In this embodiment, the determining subunit U422 is configured to determine whether differences between the gradient components of the gradient vector and zero are within the preset threshold range; when the differences between the gradient components and zero of the gradient vector are within the preset threshold range, outputting a configuration vector to be optimized to a completion subunit U423; when the difference between at least one component of the gradient vector and zero is not within the preset threshold, a return subunit U424 is entered.
When the difference value between the gradient vector corresponding to the configuration vector D i to be optimized and zero is within the preset threshold range, the function of the optimal focal plane offset converges, the minimum value of the optimal focal plane offset BFS is correspondingly obtained, and the completion subunit takes the configuration vector D i to be optimized as the optimal configuration vector D opt.
When the judging subunit U422 judges that the difference between the gradient vector corresponding to the configuration vector D i to be optimized and zero is not within the preset threshold range, the judging subunit U422 is configured to output the configuration vector to be optimized to the returning subunit U424, and the returning subunit U422 is configured to update the configuration vector to be optimized according to the variation and return to the calculating subunit U421.
The returning subunit U424 updates the configuration vector to be optimized according to the variation Δd i, and returns to the calculating subunit U421, that is, continues to search along the direction of the gradient vector corresponding to the configuration vector to be optimized until the difference between the gradient vector corresponding to the configuration vector to be optimized D i and zero is obtained within the preset threshold range, and the corresponding configuration vector to be optimized D opt is obtained.
In this embodiment, the return subunit U424 is configured to obtain an updated configuration vector D i+1 according to the configuration vector D i to be optimized and the variation Δd i, and replace the configuration vector D i to be optimized with the updated configuration vector D i+1.
Specifically, the return subunit U424 is configured to obtain the updated configuration vector D i+1 by adding the variation Δd i to the configuration vector D i to be optimized.
The configuration unit U5 is configured to set an auxiliary graph around the main graph according to a plurality of configuration parameters corresponding to the optimal configuration vector D opt.
The optimal configuration vector D opt corresponds to the minimum optimal focal plane offset or corresponds to the maximum common focal depth between the multiple types of main patterns, so that after the auxiliary patterns are set around the main patterns according to the multiple configuration parameters corresponding to the optimal configuration vector D opt, the optimal focal plane offset between the different types of main patterns in lithography is smaller, that is, the optimal focal planes of the different types of main patterns are closer, and accordingly, the overlapping part of the focal depths of the different types of main patterns reaches the maximum, thereby being beneficial to enlarging the common process window of the lithography process.
Correspondingly, the invention also provides a mask plate, which comprises: a plurality of main patterns and auxiliary patterns around the main patterns, wherein the auxiliary patterns are arranged by the optical proximity correction method of the previous embodiment.
The mask plate is used for exposing the photoresist on the wafer as a mask to form photoresist patterns of all chip areas on the wafer, and the chip areas of the wafer can be etched by the photoresist patterns, so that semiconductor structures such as a grid electrode, a metal interconnection line or a conductive plug and the like are formed in the chip areas of the wafer.
As can be seen from the foregoing embodiments, after the auxiliary patterns are set by using the optical proximity correction method in the foregoing embodiments, the optimal focal plane offset between the main patterns of different types is smaller, and the common focal depth between the main patterns of different types is larger.
The embodiment of the invention also provides equipment which can realize the optical proximity correction method provided by the embodiment of the invention by loading the optical proximity correction method in a program form. An optional hardware structure of the terminal device provided in the embodiment of the present invention may be shown in fig. 8, and includes: at least one processor 01, at least one communication interface 02, at least one memory 03 and at least one communication bus 04.
In the embodiment of the present invention, the number of the processor 01, the communication interface 02, the memory 03 and the communication bus 04 is at least one, and the processor 01, the communication interface 02 and the memory 03 complete communication with each other through the communication bus 04.
The communication interface 02 may be an interface of a communication module for performing network communication, such as an interface of a GSM module.
The processor 01 may be a central processing unit CPU, or an Application-specific integrated Circuit ASIC (Application SPECIFIC INTEGRATED Circuit), or one or more integrated circuits configured to implement embodiments of the present invention.
The memory 03 may comprise a high-speed RAM memory or may further comprise a non-volatile memory (non-volatile memory), such as at least one magnetic disk memory.
The memory 03 stores one or more computer instructions that are executed by the processor 01 to implement the access control method provided by the embodiment of the present invention.
It should be noted that, the implementation terminal device may further include other devices (not shown) that may not be necessary for the disclosure of the embodiment of the present invention; embodiments of the present invention will not be described in detail herein, as such other devices may not be necessary to an understanding of the present disclosure.
The embodiment of the invention also provides a storage medium, which stores one or more computer instructions for implementing the optical proximity correction method provided by the embodiment of the invention.
According to the optical proximity correction method provided by the embodiment of the invention, when the optical proximity correction is carried out, the configuration parameters of each main pattern are obtained, a plurality of configuration parameters corresponding to a plurality of main patterns are used for forming a configuration vector, the configuration vector has a corresponding relation with the optimal focal plane offset, the configuration vector is optimized based on the corresponding relation between the configuration vector and the optimal focal plane offset, the optimized configuration vector corresponding to the minimum optimal focal plane offset is obtained, and auxiliary patterns are arranged around the main patterns according to the plurality of configuration parameters corresponding to the optimized configuration vector, so that the optimal focal plane offset among different types of main patterns is smaller after the auxiliary patterns are arranged around the main patterns, that is, the optimal focal planes corresponding to different types of main patterns are relatively close, and the focal depth overlapping part among different types of main patterns is maximized, thereby being beneficial to obtaining a common process window of the maximized photoetching process.
The embodiments of the application described above are combinations of elements and features of the application. Unless otherwise mentioned, the elements or features may be considered optional. Each element or feature may be practiced without combining with other elements or features. In addition, embodiments of the application may be constructed by combining some of the elements and/or features. The order of operations described in embodiments of the application may be rearranged. Some configurations of any embodiment may be included in another embodiment and may be replaced with corresponding configurations of another embodiment. It will be obvious to those skilled in the art that claims which are not explicitly cited in each other in the appended claims may be combined into embodiments of the present application or may be included as new claims in a modification after submitting the present application.
Embodiments of the invention may be implemented by various means, such as hardware, firmware, software or combinations thereof. In a hardware configuration, the method according to the exemplary embodiments of the present invention may be implemented by one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.
In a firmware or software configuration, embodiments of the present invention may be implemented in the form of modules, procedures, functions, and so on. The software codes may be stored in memory units and executed by processors. The memory unit may be located inside or outside the processor and may send and receive data to and from the processor via various known means.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims (19)

1. A method of optical proximity correction comprising:
Providing a chip pattern area, wherein the chip pattern area comprises a plurality of main patterns;
Providing a corresponding preset auxiliary graph around the main graph, wherein the preset auxiliary graph has a preset width, a preset distance is arranged between the preset auxiliary graph and the corresponding main graph, and the preset distance and the preset width form configuration parameters corresponding to the main graph;
Obtaining configuration parameters of each main graph, wherein a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming a configuration vector, and the configuration vector has a corresponding relation with an optimal focal plane offset, wherein the optimal focal plane offset is that a plurality of optimal focal planes respectively correspond to the plurality of main graphs, and the difference value between the maximum value and the minimum value in the plurality of optimal focal plane values is the optimal focal plane offset among the plurality of main graphs;
optimizing the configuration vector based on the corresponding relation between the configuration vector and the optimal focal plane offset to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset;
And setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector.
2. The optical proximity correction method of claim 1 wherein the configuration vector is optimized using a gradient algorithm.
3. The optical proximity correction method of claim 2 wherein the step of optimizing the configuration vector using a gradient algorithm comprises: and obtaining a corresponding optimal configuration vector when the gradient vector of the optimal focal plane offset relative to the configuration vector is zero by adopting a gradient algorithm.
4. The optical proximity correction method according to claim 2, wherein a gradient algorithm is used to obtain a gradient vector of the optimal focal plane offset with respect to a configuration vector, and the configuration vector is optimized when a difference from zero is within a preset threshold range.
5. The optical proximity correction method of claim 4 wherein the predetermined threshold range is 10 -5 to 10 -1.
6. The optical proximity correction method of claim 1, wherein the step of optimizing the configuration vector comprises: setting an initial configuration vector, and taking the initial configuration vector as a configuration vector to be optimized; searching along the direction of the gradient vector corresponding to the configuration vector to be optimized to obtain the optimal configuration vector corresponding to the minimum optimal focal plane offset.
7. The optical proximity correction method according to claim 6, wherein the optimal configuration vector corresponding to the smallest optimal focal plane offset is obtained by searching in a direction of a gradient vector corresponding to the configuration vector to be optimized using a steepest descent method or a conjugate gradient method.
8. The optical proximity correction method according to claim 6, wherein the step of searching along a direction of a gradient vector corresponding to the configuration vector to be optimized to obtain the optimized configuration vector corresponding to the smallest optimum focal plane offset amount comprises:
setting a variable quantity for the configuration vector to be optimized, and obtaining a gradient vector of the optimal focal plane offset relative to the configuration vector to be optimized according to the variable quantity;
judging whether the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold range or not;
When the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold value range, completing the optimization processing, and taking the configuration vector to be optimized as the optimization configuration vector;
And when the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is not in the preset threshold value range, updating the configuration vector to be optimized according to the variation.
9. The optical proximity correction method according to claim 8, wherein a variation is set for the configuration vector to be optimized, and a finite difference method is used to obtain a gradient vector of the optimum focal plane offset with respect to the configuration vector to be optimized according to the variation.
10. The optical proximity correction method according to claim 8, wherein the step of updating the configuration vector to be optimized according to the variation amount includes: and obtaining an updated configuration vector according to the configuration vector to be optimized and the variation, and replacing the configuration vector to be optimized with the updated configuration vector.
11. The optical proximity correction method according to claim 8, wherein a plurality of preset distances and a plurality of preset widths respectively constitute components of the configuration vector;
The step of obtaining a gradient vector of the best focal plane offset with respect to a configuration vector to be optimized comprises: and respectively calculating partial derivatives of the optimal focal plane offset with respect to each component on the basis of a configuration vector to be optimized, wherein the partial derivatives are used as gradient components in the corresponding direction of each component, and a plurality of gradient components in the corresponding direction of a plurality of components form the gradient vector.
12. The optical proximity correction method of claim 1, wherein the auxiliary pattern comprises a scattering bar.
13. The optical proximity correction method of claim 1, wherein the primary pattern is a pattern comprising an elongated pattern, a rectangular pattern, or a square pattern.
14. An optical proximity correction system, comprising:
A main pattern providing unit for providing a chip pattern area including a plurality of main patterns;
The preset unit is used for providing corresponding preset auxiliary graphics around the main graphics, the preset auxiliary graphics have preset widths, preset distances are arranged between the preset auxiliary graphics and the corresponding main graphics, and the preset distances and the preset widths form configuration parameters corresponding to the main graphics;
The device comprises an acquisition unit, a configuration vector and a configuration vector, wherein the acquisition unit is used for acquiring configuration parameters of each main graph, a plurality of configuration parameters corresponding to a plurality of main graphs are used for forming the configuration vector, the configuration vector has a corresponding relation with an optimal focal plane offset, the optimal focal plane offset is that a plurality of optimal focal planes respectively correspond to a plurality of main graphs, and the difference value between the maximum value and the minimum value in a plurality of optimal focal plane values is the optimal focal plane offset between the plurality of main graphs;
the optimization processing unit is used for carrying out optimization processing on the configuration vector based on the corresponding relation between the configuration vector and the optimal focal plane offset to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset;
and the configuration unit is used for setting auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vector.
15. The optical proximity correction system of claim 14, wherein the optimization processing unit comprises: the initial setting unit is used for setting an initial configuration vector and taking the initial configuration vector as a configuration vector to be optimized;
and the searching unit is used for searching along the direction of the gradient vector corresponding to the configuration vector to be optimized to obtain the optimal configuration vector corresponding to the minimum optimal focal plane offset.
16. The optical proximity correction system of claim 15, wherein the search unit comprises: the calculating subunit is used for setting a variation for the configuration vector to be optimized and obtaining a gradient vector of the optimal focal plane offset relative to the configuration vector to be optimized according to the variation;
The judging subunit is used for judging whether the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold range;
when the judging subunit judges that the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold value range, the judging subunit is used for outputting the configuration vector to be optimized to a finishing subunit, and the finishing subunit is used for taking the configuration vector to be optimized as the optimized configuration vector;
When the judging subunit judges that the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is not in the preset threshold value range, the judging subunit is used for outputting the configuration vector to be optimized to a returning subunit, and the returning subunit is used for updating the configuration vector to be optimized according to the variation and returning to the calculating subunit.
17. A reticle, comprising: a plurality of primary patterns and auxiliary patterns located around the primary patterns, the auxiliary patterns being provided by the optical proximity correction method as claimed in any one of claims 1 to 13.
18. An apparatus for optical proximity correction comprising at least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method of any of claims 1-13.
19. A storage medium having stored thereon one or more computer instructions for implementing the optical proximity correction method of any one of claims 1-13.
CN201911380417.4A 2019-12-27 2019-12-27 Optical proximity correction method and system, mask, equipment and storage medium Active CN113050366B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911380417.4A CN113050366B (en) 2019-12-27 2019-12-27 Optical proximity correction method and system, mask, equipment and storage medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911380417.4A CN113050366B (en) 2019-12-27 2019-12-27 Optical proximity correction method and system, mask, equipment and storage medium

Publications (2)

Publication Number Publication Date
CN113050366A CN113050366A (en) 2021-06-29
CN113050366B true CN113050366B (en) 2024-05-17

Family

ID=76506797

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911380417.4A Active CN113050366B (en) 2019-12-27 2019-12-27 Optical proximity correction method and system, mask, equipment and storage medium

Country Status (1)

Country Link
CN (1) CN113050366B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115718404B (en) * 2023-01-06 2023-11-28 Tcl华星光电技术有限公司 Optical proximity correction method, mask plate and display panel
CN115877650B (en) * 2023-01-30 2023-05-30 合肥新晶集成电路有限公司 Method for adding scattering bars and method for preparing mask
CN116203791A (en) * 2023-04-28 2023-06-02 合肥晶合集成电路股份有限公司 Mask structure of semiconductor chip and semiconductor device

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06242594A (en) * 1993-02-15 1994-09-02 Sharp Corp Mask for deformed illuminating exposure device
US5415952A (en) * 1992-10-05 1995-05-16 Fujitsu Limited Fine pattern lithography with positive use of interference
CN101246306A (en) * 2007-02-12 2008-08-20 中芯国际集成电路制造(上海)有限公司 Optical proximity amending method
CN101788759A (en) * 2009-01-23 2010-07-28 中芯国际集成电路制造(上海)有限公司 Method for correcting auxiliary figure with low resolution
CN102043325A (en) * 2009-10-13 2011-05-04 中芯国际集成电路制造(上海)有限公司 Mask graph correcting method and mask manufacturing method
US8458626B1 (en) * 2012-01-20 2013-06-04 International Business Machines Corporation Method for calibrating an SRAF printing model
CN103631083A (en) * 2012-08-20 2014-03-12 中芯国际集成电路制造(上海)有限公司 Optical proximity correction focal plane selecting method
CN104570585A (en) * 2013-10-23 2015-04-29 中芯国际集成电路制造(上海)有限公司 Optical proximity correction method
CN106094423A (en) * 2016-08-22 2016-11-09 上海华力微电子有限公司 A kind of photoetching process optimization method
CN107111237A (en) * 2014-10-02 2017-08-29 Asml荷兰有限公司 The rule-based deployment of supplemental characteristic
CN107643651A (en) * 2017-10-09 2018-01-30 上海华力微电子有限公司 A kind of design method of photoetching secondary graphics
CN109188870A (en) * 2018-09-30 2019-01-11 上海华力集成电路制造有限公司 Optical proximity correction method
CN110058485A (en) * 2019-05-09 2019-07-26 上海华力微电子有限公司 OPC modification method and OPC update the system
CN110456610A (en) * 2019-08-29 2019-11-15 上海华力集成电路制造有限公司 Optimize the secondary graphics and method of via layer process window

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001061412A1 (en) * 2000-02-14 2001-08-23 Asml Masktools B.V. A method of improving photomask geometry
US7954071B2 (en) * 2008-10-31 2011-05-31 Synopsys, Inc. Assist feature placement based on a focus-sensitive cost-covariance field
WO2016008711A1 (en) * 2014-07-14 2016-01-21 Asml Netherlands B.V. Optimization of assist features and source

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5415952A (en) * 1992-10-05 1995-05-16 Fujitsu Limited Fine pattern lithography with positive use of interference
JPH06242594A (en) * 1993-02-15 1994-09-02 Sharp Corp Mask for deformed illuminating exposure device
CN101246306A (en) * 2007-02-12 2008-08-20 中芯国际集成电路制造(上海)有限公司 Optical proximity amending method
CN101788759A (en) * 2009-01-23 2010-07-28 中芯国际集成电路制造(上海)有限公司 Method for correcting auxiliary figure with low resolution
CN102043325A (en) * 2009-10-13 2011-05-04 中芯国际集成电路制造(上海)有限公司 Mask graph correcting method and mask manufacturing method
US8458626B1 (en) * 2012-01-20 2013-06-04 International Business Machines Corporation Method for calibrating an SRAF printing model
CN103631083A (en) * 2012-08-20 2014-03-12 中芯国际集成电路制造(上海)有限公司 Optical proximity correction focal plane selecting method
CN104570585A (en) * 2013-10-23 2015-04-29 中芯国际集成电路制造(上海)有限公司 Optical proximity correction method
CN107111237A (en) * 2014-10-02 2017-08-29 Asml荷兰有限公司 The rule-based deployment of supplemental characteristic
CN106094423A (en) * 2016-08-22 2016-11-09 上海华力微电子有限公司 A kind of photoetching process optimization method
CN107643651A (en) * 2017-10-09 2018-01-30 上海华力微电子有限公司 A kind of design method of photoetching secondary graphics
CN109188870A (en) * 2018-09-30 2019-01-11 上海华力集成电路制造有限公司 Optical proximity correction method
CN110058485A (en) * 2019-05-09 2019-07-26 上海华力微电子有限公司 OPC modification method and OPC update the system
CN110456610A (en) * 2019-08-29 2019-11-15 上海华力集成电路制造有限公司 Optimize the secondary graphics and method of via layer process window

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
《Automated optical proximity correction—a rules-based approach》;Oberdan W. Otto;《Proc SPIE2197，Optical/Laser Microlithography》;19940517;278-293 *
《光学光刻中的邻近效应校正新方法研究》;杜惊雷;《第十届全国电子束离子束光子束学术年会》;19991101;321-325 *

Also Published As

Publication number Publication date
CN113050366A (en) 2021-06-29

Similar Documents

Publication Publication Date Title
CN108333865B (en) Method for correcting mask graph
CN113050366B (en) Optical proximity correction method and system, mask, equipment and storage medium
US5994009A (en) Interlayer method utilizing CAD for process-induced proximity effect correction
KR100473197B1 (en) Method and apparatus for determining phase shifts and trim masks for an integrated circuit
US20070275309A1 (en) Patterning A Single Integrated Circuit Layer Using Multiple Masks And Multiple Masking Layers
TWI742184B (en) Target optimization method
US20040063038A1 (en) New method to reduce CD non-uniformity in IC manufacturing
US8975195B2 (en) Methods for optical proximity correction in the design and fabrication of integrated circuits
US20080280217A1 (en) Patterning A Single Integrated Circuit Layer Using Multiple Masks And Multiple Masking Layers
US11763057B2 (en) Critical dimension uniformity
CN114326290A (en) Optical proximity correction method
JP4115615B2 (en) Mask pattern design method
US8302068B2 (en) Leakage aware design post-processing
CN109828433B (en) Method of correcting mask layout and method of manufacturing semiconductor device using the same
KR20210156399A (en) Method for OPC and method for manufacturing semiconductor device using the same
US8742546B2 (en) Semiconductor device with a plurality of dot patterns and a line pattern having a projection part
JP2004157160A (en) Method for forming process model, method for designing mask pattern, mask and method for manufacturing semiconductor device
CN114063380A (en) Pattern correction method and method for forming semiconductor structure
JP4580656B2 (en) Double exposure photomask and exposure method
WO2009125529A1 (en) Method of generating mask pattern and method of forming pattern
US7838181B2 (en) Photo mask and method for manufacturing semiconductor device using the same
JP7381730B2 (en) Lithography simulation and optical proximity correction
KR100834234B1 (en) Method for forming mask pattern for fabricating semiconductor device
KR102675303B1 (en) Method for manufacturing semiconductor device
Holmes et al. Edge lithography as a means of extending the limits of optical and nonoptical lithographic resolution

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant