CN113050366A

CN113050366A - Optical proximity correction method and system, mask, equipment and storage medium

Info

Publication number: CN113050366A
Application number: CN201911380417.4A
Authority: CN
Inventors: 柏锋; 杜杳隽; 李甲兮; 张婉娟; 李亮
Original assignee: Semiconductor Manufacturing International Shanghai Corp; Semiconductor Manufacturing International Beijing Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp; Semiconductor Manufacturing International Beijing Corp
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2021-06-29

Abstract

An optical proximity correction method and system, a mask, equipment and a storage medium are provided, 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 formed 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 pattern, wherein a plurality of configuration parameters corresponding to various main patterns are used for forming configuration vectors, and the configuration vectors have 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 arranging auxiliary graphics around the main graphics according to a plurality of configuration parameters corresponding to the optimized configuration vectors. The embodiment of the invention is beneficial to increasing 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

The photoetching technology is a vital technology in the semiconductor manufacturing technology, and can realize the transfer of a pattern from a mask to the surface of a silicon wafer to form a semiconductor product meeting the design requirement. The photolithography process includes an exposure step, and a development step performed after the exposure step. In the exposure step, light irradiates on a silicon wafer coated with photoresist through a light-transmitting area in a mask plate, and the photoresist undergoes a chemical reaction under the irradiation of the light; in the developing step, a photoetching pattern is formed by utilizing the difference of the dissolution degree of photosensitive photoresist and non-photosensitive photoresist to a developer, so that the mask pattern is transferred to the photoresist. After the photolithography process, an etching step is usually performed, that is, the silicon wafer is etched based on the photolithography pattern formed by the photoresist layer, and the pattern of the mask is further transferred to the silicon wafer.

In semiconductor manufacturing, as the design size is continuously reduced and the design size is closer to the limit of the lithography imaging system, the diffraction Effect of light becomes more and more obvious, which causes the Optical image degradation of the design pattern, the actual formed lithography pattern is seriously distorted relative to the pattern on the mask, and the actual pattern and the design pattern formed by lithography on the silicon wafer are different, and this phenomenon is called Optical Proximity Effect (OPE). Sub-Resolution Assist Features (Sub-Resolution Assist Features), Optical Proximity Correction (OPC), Inverse Lithography (ILT), Double Patterning, Self-aligned Double Patterning, and the like are used to improve the Lithography Resolution.

The Scattering Bar (SB) is a sub-resolution auxiliary pattern, and the auxiliary pattern Bar is arranged around the Main pattern (Main Feature) to improve the lithography quality of the Main pattern. Wherein, the main pattern is an exposable pattern, and the scattering bars are usually non-exposable patterns.

Disclosure of Invention

The embodiment of the invention provides an optical proximity correction method and system, a mask, equipment and a storage medium, and aims to increase a common process window of a photoetching process.

To solve the above problem, 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 formed 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 pattern, wherein a plurality of configuration parameters corresponding to a plurality of main patterns 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 arranging auxiliary graphs around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vectors.

Accordingly, an embodiment of the present invention further provides an optical proximity correction system, including: a main pattern providing unit for providing a chip pattern region including a plurality of main patterns; the preset unit is used for providing a corresponding preset auxiliary graph around the main graph, the preset auxiliary graph has a preset width, a preset distance is reserved 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; the acquisition unit is used for acquiring the configuration parameters of each main pattern, a plurality of configuration parameters corresponding to a plurality of main patterns are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset; the optimization processing unit is used for 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 the configuration unit is used for setting an auxiliary graph around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vector.

Correspondingly, the embodiment of the invention also provides a mask, which comprises: a plurality of main patterns and auxiliary patterns positioned around the main patterns, the auxiliary patterns being set by the aforementioned optical proximity correction method.

Accordingly, embodiments of the present invention also provide an apparatus, including at least one memory and at least one processor, where the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the aforementioned optical proximity correction method.

Accordingly, embodiments of the present invention also provide a storage medium storing one or more computer instructions for implementing the aforementioned 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 present invention, preset auxiliary patterns are provided around the main pattern, and configuration parameters of each main pattern are obtained, a plurality of configuration parameters corresponding to a plurality of main patterns are used to form a configuration vector, the configuration vector has a corresponding relationship with an optimal focal plane offset, then based on the corresponding relationship between the configuration vector and the optimal focal plane offset (BFS), the configuration vector is optimized to obtain an optimized configuration vector corresponding to the minimum optimal focal plane offset, and then according to the plurality of configuration parameters corresponding to the optimized configuration vector, auxiliary patterns are provided around the main pattern, so as to help ensure that the optimal focal plane offset between main patterns of different types is small after the auxiliary patterns are provided around the main pattern, that is, the Best focal planes (Best focus) corresponding to the different types of main patterns are relatively close, which is beneficial to maximizing the focal depth overlapping part between the different types of main patterns, thereby being beneficial to obtaining the maximized Common process window (Common process window) of the photoetching process.

Drawings

FIG. 1 is a flow chart of an embodiment of a method for optical proximity correction 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 in the background art, it is one of the commonly used resolution enhancement techniques to dispose sub-resolution auxiliary patterns around the main pattern of the mask to improve the lithography quality of the main pattern.

However, the current method for setting the sub-resolution auxiliary pattern may cause a larger Best focus plane offset (BFS) between different types of main patterns (main patterns), and a smaller overlapping portion of different types of focal depths, which may reduce a common process window for photolithography of the entire mask. The sub-resolution auxiliary pattern is described as Scattering bars (Scattering bars) as an example.

The existing method for setting the scattering bar comprises an empirical rule-based auxiliary pattern (Rules-based SRAF) setting method, and the method sets the scattering bar around a main pattern based on the empirical rule, that is, the width of the scattering bar and the distance from the scattering bar to the main pattern are adjusted according to an empirical artificial preset configuration rule and by combining the information of the characteristic size, the distance and the like of the main pattern.

Still another method is a model-based auxiliary pattern setting method, which simulates actual exposure results according to the size of the scattering bars and the inserted positions and then continuously adjusts these parameters to make the main pattern reach the best focus plane and the maximum depth of focus. Or, based on past experience and data information of main patterns on the wafer, the scattering bars are directly arranged on the mask.

However, the above methods are all for setting the position and size of the scattering bar with the purpose of achieving the best focus plane and the maximum focal depth with a local main pattern. For example: the above methods are to arrange scattering bars around the main pattern according to the characteristic size and the distance of each type of main pattern, so as to make the local main pattern reach the optimal focusing plane and the maximum focal depth. After the scattering bars are added according to the method, the scattering bars easily influence the common focal depth of the photoetching process, that is, the scattering bars easily cause that the overlapped part of the focal depths of different types of main patterns is small, the Best focus plane offset (Best focus shift) between the different types of main patterns is large, and further the photoetching common process window of the whole layout is reduced.

In order to solve the technical problem, an embodiment of the present invention provides an optical proximity correction method, in which preset auxiliary patterns are provided around a main pattern, and configuration parameters of each main pattern are obtained, a plurality of configuration parameters corresponding to a plurality of main patterns are used to form a configuration vector, the configuration vector has a corresponding relationship with an optimal focal plane offset, then based on the corresponding relationship between the configuration vector and the optimal focal plane offset, the configuration vector is optimized to obtain an optimized configuration vector corresponding to a minimum optimal focal plane offset, and then auxiliary patterns are provided around the main pattern according to a plurality of configuration parameters corresponding to the optimized configuration vector, so as to ensure that the optimal focal plane offset between different types of main patterns is small after the auxiliary patterns are provided around the main pattern, that is to say, the optimal focal planes (Best focus) corresponding to different types of main patterns are relatively close, and the focal depth overlapping part between different types of main patterns is maximized, thereby being beneficial to obtaining the maximized common process window of the photoetching process.

Referring to FIG. 1, a flow chart of an embodiment of the optical proximity correction method of the present invention is shown. Referring collectively to FIG. 2, a flowchart of one embodiment of step S4 of FIG. 1 is shown. Referring collectively to FIG. 3, a flowchart of one embodiment of step S42 of FIG. 2 is shown. As an example, the optical proximity correction method according to 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 a preset auxiliary graph around the main graph, wherein the preset auxiliary graph has a preset width, a preset distance is formed 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 pattern, wherein a plurality of configuration parameters corresponding to a plurality of main patterns are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset;

step S4: 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;

step S5: and arranging auxiliary graphs around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vectors.

In order to make the aforementioned objects, features and advantages of the embodiments of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

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 used by a chip in a photoetching process, the mask is used as a mask to expose photoresist on the wafer so as to form photoresist patterns of each chip area 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 wire or a conductive plug and the like in the chip areas of the wafer. The wafer comprises a plurality of chip areas which are arranged in an array mode, 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), which are different for the plurality of types of main patterns. 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, three main patterns with different types of target feature sizes and target pitches in the present embodiment are respectively shown: a first main pattern a1, a second main pattern a2, and a third main pattern A3.

As an example, in the present embodiment, the first main pattern a1 is a long bar pattern, the second main pattern a2 is a rectangular pattern, and the third main pattern A3 is a square pattern.

Continuing to refer to fig. 1, executing step S2 to provide a corresponding preset auxiliary graph around the main graph; the preset auxiliary pattern has a preset width w, a preset distance d is arranged between the preset auxiliary pattern and the corresponding main pattern, and the preset distance d and the preset width w form configuration parameters (d, w) corresponding to the main pattern.

And the preset auxiliary graph is used for carrying out optimization processing subsequently to prepare for obtaining an optimized configuration vector.

In this embodiment, the auxiliary pattern includes scattering bars. Scattering Bars (SB) are a sub-resolution auxiliary pattern. The scattering strip has the following advantages: firstly, the profile line width of a photoetching pattern can be sensed, the light intensity contrast is improved, and the Edge Placement Error (Edge Placement Error) is reduced; secondly, the depth of focus is increased, thereby improving the photolithography process window.

With continuing reference to fig. 1, step S3 is executed to obtain configuration parameters of each of the main patterns, and the configuration parameters (D, w) of the plurality of main patterns are used to form a configuration vector D, where the configuration vector D has a corresponding relationship with the optimal focal plane offset.

In this embodiment, the configuration vector D is composed of configuration parameters (D, w) of a plurality of main patterns, and the configuration vector D can be represented by formula (i):

D＝(d₁,w₁,d₂,w₂,……,d_N,w_N) (Ⅰ)

where N denotes a main pattern having an 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 subsequent optimization processing.

With combined reference to fig. 4, 5 and 6, it is illustrated that the main pattern and the corresponding preset auxiliary pattern are provided in the present embodiment. In the present embodiment, a first preset auxiliary graphic B1 is disposed around the first main graphic a1, a second preset auxiliary graphic B2 is disposed around the second main graphic B1, and a third preset auxiliary graphic B3 is disposed around the third main graphic A3, respectively.

The first preset auxiliary pattern B1 has a preset distance d1 and a preset width w1, the second preset auxiliary pattern B2 has a preset distance d2 and a preset width w2, and the third preset auxiliary pattern B3 has a preset distance d3 and a preset width w 3.

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 focal plane offset (BFS). Specifically, the configuration vector D has a correspondence relationship with an optimal focal plane offset (BFS) between a plurality of main patterns.

Each master pattern has a corresponding optimal focal plane. The optimal focal plane offset refers to: and obtaining the maximum value and the minimum value of the optimal focal plane values for a plurality of optimal focal planes respectively corresponding to the main graphs, wherein the difference value between the maximum value and the minimum value is the optimal focal plane offset between the main graphs, namely the optimal focal plane offset.

After providing the 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 optimal focal plane offset and the configuration vector D, that is, when assigning values to a plurality of configuration parameters corresponding to the configuration vector D, for each configuration vector D, according to a certain rule F, there is a uniquely determined optimal focal plane offset corresponding to the configuration vector D.

In this embodiment, a plurality of configuration parameters (D, w) corresponding to a plurality of main patterns are used to form a configuration vector D, the configuration vector D is used as an independent variable, and a function f (D) of an optimal focal plane offset is used as an objective function of subsequent optimization processing, so that the optimal focal planes of the plurality of main patterns during lithography can be considered, and when an 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, and a maximized common process window of the lithography process can be obtained.

Specifically, the smaller the offset of the optimal focal plane between the different types of main patterns is, the closer the optimal focal plane of the different types of main patterns is, the larger the common focal depth between the different types of main patterns is, and accordingly, the larger the common process window for photolithography is.

In an actual process, for each of the configuration vectors D, the step of obtaining the corresponding optimal focal plane offset may include: on the basis of the configuration vector D, respectively obtaining an optimal focal plane corresponding to each type of main pattern, and obtaining a plurality of optimal focal planes; maximum and minimum values in the plurality of best focus planes are obtained, and the maximum value minus the minimum value is used as the best focus plane offset. Wherein, the optimal focal plane corresponding to each type of main graph can be obtained by means of optical simulation.

With continuing reference to FIG. 1, steps are performedS4, based on the corresponding relation between the configuration vector D and the optimal focal plane offset (BFS), optimizing the configuration vector D to obtain the optimized configuration vector D corresponding to the minimum optimal focal plane offset_opt。

Optimizing the configuration vector D based on the corresponding relation between the configuration vector D and the optimal focal plane offset (BFS) to obtain the optimized configuration vector D corresponding to the minimum optimal focal plane offset_optSo that subsequently a vector D can be configured according to said optimization_optCorresponding configuration parameters, auxiliary graphics are arranged around the main graphics, thereby being beneficial to ensuring that the vector D is configured according to the optimization_optAfter the auxiliary patterns are set by the corresponding configuration parameters, the optimal focal plane offset (BFS) between the main patterns of different types is small during the photolithography process, that is, the optimal focal planes between the main patterns of different types are relatively close, which is beneficial to maximizing the focal depth overlapping part between the main patterns of different types, thereby being beneficial to obtaining the maximized Common process window (Common process window) of the photolithography process.

In this embodiment, a numerical optimizer (numerical optimizer) is used to optimize the configuration vector D. In this embodiment, a gradient algorithm may be adopted to perform optimization processing on the configuration vector D.

In this embodiment, the step of performing optimization processing on the configuration vector D by using a gradient algorithm includes: as shown in formula (iii), when the function f (D) of the optimal focal plane offset is obtained by using a gradient algorithm, and the partial derivative of the function f (D) with respect to the configuration vector D is zero, the corresponding optimal configuration vector D is obtained_opt. That is, when 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, the corresponding optimal configuration vector D is obtained_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, the optimal focal plane offset BFS converges accordingly, that is to say the optimal focal plane offset BFS obtains a minimum value accordingly.

Specifically, in the actual operation, a gradient algorithm is adopted to obtain a function f (D) of the optimal focal plane offset, a difference value between a gradient vector of the optimal focal plane offset and zero is within a preset Threshold (Threshold), and a corresponding optimal configuration vector D is obtained_opt。

The preset threshold range is not too small or too large. If the preset threshold range is too small, the speed of optimization processing is easy to be too low, and the efficiency of optimization processing is easy to be reduced; if the preset threshold range is too large, the optimization process is easy to be incomplete, for example: the optimal focal plane offset corresponding to the optimized configuration vector obtained after the optimization process may not be the minimum. For this reason, in this embodiment, the preset threshold range is 10^-5To 10^-1For example: the preset threshold range is 0.001, 0.0001 and the like.

With reference to fig. 1 and fig. 2 in combination, fig. 2 is a flowchart of an embodiment of step S4 in fig. 1, and in this embodiment, the step of performing optimization processing on the configuration vector D includes:

step S41 is executed to set the initial configuration vector D₀With said initial configuration vector D₀As a configuration vector D to be optimized_i；

Step S42 is executed to follow the configuration vector D to be optimized_iSearching the direction of the corresponding gradient vector to obtain the optimal configuration vector D corresponding to the minimum optimal focal plane offset_opt。

As an example, the following describes in detail specific steps of performing optimization processing on the configuration vector D in this embodiment with reference to the drawings.

Step S41 is executed to set the initial configuration vector D₀With said initial configuration vector D₀As a configuration vector D to be optimized_i. By setting an initial configuration vector D₀As a configuration vector D to be optimized_iFor subsequent alignment with the configuration vector D to be optimized_iCorresponding gradientA vector direction search is prepared.

Wherein the configuration vector D to be optimized_iMay be an initial configuration vector D₀Or may be a configuration vector D to be optimized in the subsequent search process_i。

In this embodiment, the configuration vector D to be optimized_iDetermined by the formula (iv):

D_i＝(d_i,1,w_i,1,d_i,2,w_i,2,……,d_i,N,w_i,N) (Ⅳ)

wherein i is a positive integer from 0 to N. When i is 0, the configuration vector D to be optimized_iFor initial configuration of vector D₀。

Specifically, in this embodiment, the optimal configuration vector D corresponding to the difference between the gradient vector and zero in the preset threshold range is obtained_opt。

In this embodiment, the configuration vector D to be optimized is followed by the steepest descent method_iSearching the direction of the corresponding gradient vector to obtain the optimal configuration vector D corresponding to the minimum optimal focal plane offset_opt. The steepest descent method descends along the direction of the negative gradient, so as to obtain the corresponding optimal configuration vector D when the difference value between the gradient vector and zero is within the preset threshold range_optThen, the configuration vector D is obtained and optimized accordingly_optCorresponding to the minimum optimum focal plane offset BFS.

In other embodiments, a conjugate gradient method or other search algorithms may also be used to search along the direction of the gradient vector to obtain the optimal configuration vector corresponding to the gradient vector when the gradient vector is zero.

Referring to fig. 3 in combination, fig. 3 is a flowchart of an embodiment of step S42 in fig. 2, in this embodiment, the configuration vector D to be optimized is followed_iThe direction search of the corresponding gradient vector is carried out to obtain the minimumOptimal configuration vector D corresponding to good focal plane offset_optComprises the following steps:

executing step S421, and configuring the vector D to be optimized_iSetting a variation quantity Delta D_iAnd according to said variation quantity DeltaD_iObtaining the optimal focal plane offset with respect to the configuration vector D to be optimized_iThe gradient vector of (2).

By treating the optimized configuration vector D_iSetting a variation quantity Delta D_iFor obtaining said optimal focal plane offset with respect to the configuration vector D to be optimized_iThe gradient vector of (a) is prepared.

In this embodiment, the configuration vector D to be optimized is calculated_iSetting a variation quantity Delta D_iComprises the following steps: in the configuration vector D to be optimized_iOn the basis of the corresponding configuration parameters, distance offset delta D is set for a plurality of preset distances D, width offset delta w is set for a plurality of preset widths w, and the variation delta D is formed by the distance offsets delta D and the width offsets delta w_i。

In this embodiment, a finite difference method is used to obtain a function F (D) of the optimal focal plane offset with respect to a configuration vector D to be optimized_iThe gradient vector of (2). The finite difference method is a numerical solution, in which the differential equation is replaced by the partial derivative to obtain the corresponding differential equation, and the approximate value of the differential equation solution is obtained by solving the differential equation.

In this embodiment, an optimal focal plane offset function F (D) is obtained for a configuration vector D to be optimized_iThe step of gradient vector of (2) comprises: for the configuration vector D to be optimized_iSetting a variation quantity Delta D_iThen, the variation quantity DeltaD is obtained_iThe variation quantity Δ f (d) of the corresponding optimum focal plane offset; dividing the variation quantity DeltaF (D) of the optimal focal plane offset quantity by the variation quantity DeltaD to obtain a configuration vector D to be optimized_iCorresponding gradient vector

The plurality of predetermined distances D and predetermined widths w each form a component of the configuration vector D, i.e. the configuration vector D has a plurality of components (D)₁,w₁,d₂,w₂,……,d_N,w_N)。

Specifically, in this embodiment, the optimal focal plane offset is obtained with respect to the configuration vector D to be optimized_iThe step of gradient vector of (2) comprises: in the configuration vector D to be optimized_iAnd amount of change Δ D_iOn the basis, partial derivatives of the optimal focal plane offset with respect to each component are respectively calculated and used as gradient components in the direction corresponding to each component, and the gradient components in the directions corresponding to the components form the gradient vector.

Wherein in the configuration vector D to be optimized_iRespectively setting an offset for each component under a plurality of different components; and then respectively solving partial derivatives of 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 direction corresponding to the plurality of components form the gradient vector.

As an example, the step of obtaining the gradient component corresponding to the component d1 may be as follows:

on the basis of the d1 component, under the condition that other components are not changed, obtaining the optimal focal plane offset F1 corresponding to the d1 component; subsequently, on the basis of the d1 component, a distance offset Δ d is set, i.e., d1 is changed to d1+ Δd; then on the basis of d1 plus delta d, obtaining the optimal focal plane offset F2 corresponding to d1 plus delta d, and subtracting the optimal focal plane offset F1 corresponding to d1 component from the optimal focal plane offset F2 corresponding to d1 plus delta d to obtain the variation delta F1 of the optimal focal plane offset_d1(ii) a Amount of change Δ F according to optimum focal plane offset_d1And a distance offset Δ d, and calculates a gradient component in the direction (i.e., a partial derivative component) corresponding to the d1 component.

It should be noted that, when calculating the gradient component corresponding to one component, the other components are kept unchanged.

Wherein the step of obtaining the optimal focal plane offset comprises: firstly, respectively obtaining an optimal focal plane corresponding to each type of main pattern, and obtaining a plurality of optimal focal planes; and obtaining the maximum value and the minimum value in the optimal focal planes, and subtracting the minimum value from the maximum value to obtain the optimal focal plane offset.

Specifically, by calculating the amount of change Δ F in the optimum focal plane offset_d1The quotient of said distance offset Δ d is taken as the gradient component in the direction corresponding to the d1 component.

And repeating the steps, and respectively calculating gradient components in the direction corresponding to each component for a plurality of components of the configuration vector D, wherein the gradient components form the gradient vector.

Step S422 is executed to determine the configuration vector D to be optimized_iWhether the difference value of the corresponding gradient vector and zero is within a preset Threshold value (Threshold) range; when it is associated with the configuration vector D to be optimized_iWhen the difference between the corresponding gradient vector and zero is within the preset threshold range, step S423 is executed to complete the optimization process, and the configuration vector D to be optimized is used_iAs said optimized configuration vector D_opt(ii) a When it is associated with the configuration vector D to be optimized_iIf the difference between the corresponding gradient vector and zero is not within the preset threshold range, step S424 is executed, and the variation Δ D is determined according to the difference_iAnd updating the configuration vector to be optimized.

In this embodiment, the configuration vector D to be optimized is determined_optThe step of determining whether the difference between the corresponding gradient vector and zero is within a preset threshold comprises: respectively judging whether the difference values of a plurality of gradient components of the gradient vector and zero are all within a preset threshold range; when the difference values of the gradient components of the gradient vector and zero are all within a preset threshold range, finishing optimization processing; when the difference between at least one component of the gradient vector and zero is not within a threshold range, according to the variation quantity Δ D_iUpdating the configuration vector D to be optimized_i。

And (c) as shown in the formula (v), when the quotient of the variation of the optimal focal plane offset and the variation is zero, correspondingly obtaining the minimum value of the optimal focal plane offset and the corresponding optimal configuration vector.

In practical operation, when the configuration vector D to be optimized_iWhen the difference between the corresponding gradient vector and zero is within the preset threshold range, the function f (d) of the optimal focal plane offset (BFS) converges, and accordingly the minimum value of the optimal focal plane offset is also obtained, so that step S423 may be executed to complete the optimization process.

When and the configuration vector D to be optimized_iWhen the difference value between the corresponding gradient vector and zero is not in the preset threshold value range, the configuration vector D to be optimized is explained_iThe corresponding best focal plane offset does not reach the minimum value, therefore, step S424 needs to be executed according to the variation Δ D_iUpdating the configuration vector D to be optimized_i。

By means of a function of said variation Δ D_iUpdating the configuration vector D to be optimized_iSo as to return to the execution of step S421, that is to say to continue along with the configuration vector D to be optimized_iSearching the direction of the corresponding gradient vector until obtaining the configuration vector D to be optimized_iWhen the difference value between the corresponding gradient vector and zero is within the preset threshold value range, the corresponding optimized configuration vector D_opt。

In this embodiment, step S424 is executed according to the variation Δ D_iThe step of updating the configuration vector to be optimized comprises: according to the configuration vector D to be optimized_iAnd amount of change Δ D_iObtaining an updated configuration vector D_i+1With said updated configuration vector D_i+1Replacing the configuration vector D to be optimized_i. In particular, using the configuration vector D to be optimized_iPlus a variation DeltaD_iObtaining the updated configuration vector D_i+1。

In the present embodiment, the configuration vector D in the search process in the direction along the gradient vector_iDetermined by the aforementioned formula (iv). It is composed ofWhen i is equal to N, the configuration vector D is the optimized configuration vector D obtained after the nth update, that is, the last optimization of the configuration vector to be optimized_opt. That is, if the optimum focal plane shift amount between the different kinds of main patterns converges from changing i from N to N +1, it is explained that the optimum focal plane shift amount between the different kinds of main patterns reaches the minimum value, and the optimization processing is completed.

As shown in Table 1, the optimized configuration vector D obtained in the present embodiment is shown_optA corresponding plurality of configuration parameters. Where the first row in table 1 is the pitch (pitch) (unit: nm) of the main pattern, the first column is the feature size (CD) (unit: nm) of the main pattern, and the other cells in table 1 illustrate the configuration parameters corresponding to the pitch and feature size, such as: for a main pattern with a feature size of 50nm and a pitch of 140nm, the corresponding configuration parameters are (60, 20), that is, the distance from the auxiliary pattern to the main pattern is 60nm, and the line width of the auxiliary pattern is 20 nm.

TABLE 1

With continued reference to FIG. 1, step S5 is performed to configure vector D according to the optimization_optAnd arranging auxiliary graphs around the main graph according to the plurality of configuration parameters.

Optimized configuration vector D_optCorresponding to the smallest optimal focal plane offset, or to the largest common focal depth, so as to configure vector D according to said optimization_optAfter the auxiliary patterns are arranged around the main patterns corresponding to a plurality of configuration parameters, during photoetching, the optimal focal planes between different main patterns are relatively close, namely, the optimal focal plane offset (BFS) between different types of main patterns is relatively small, and the common focal depth between different types of main patterns is relatively largeLarge, thereby facilitating an increase in the common process window of the lithographic process.

Specifically, the auxiliary pattern may be disposed around the main pattern according to the configuration parameters in table 1.

Correspondingly, the invention also provides an optical proximity correction system. Referring to FIG. 7, a functional block diagram of an embodiment of the 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, the preset auxiliary pattern and the corresponding main pattern have a preset distance s therebetween, 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 of the main patterns, where multiple configuration parameters corresponding to multiple 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 corresponding relationship between the configuration vector D and the optimal focal plane offset, to obtain an optimized configuration vector D corresponding to the minimum optimal focal plane offset_opt(ii) a A configuration unit U5 for configuring the vector D according to the optimization_optAnd arranging auxiliary graphs around the main graph according to the plurality of configuration parameters.

The chip pattern area provided by the main pattern providing unit U1 is used for manufacturing a mask used by a chip in a photolithography process, and the mask is used as a mask to expose photoresist on a wafer to form a photoresist pattern of each chip area on the wafer, and the photoresist pattern is used to etch the chip area of the wafer and form semiconductor structures such as a gate, a metal interconnection line or a conductive plug in the chip area of the wafer.

The wafer comprises a plurality of chip areas which are arranged in an array mode, and cutting channels are arranged between the adjacent chip areas. The main pattern is an exposable pattern and is 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 long strip pattern, a rectangular pattern or a square pattern.

The preset unit U2 is used to provide preset auxiliary graphics and configuration parameters corresponding to the main graphics, so as to prepare for the obtaining unit to obtain the configuration parameters of each main graphics.

In this embodiment, the auxiliary pattern includes scattering bars. The scattering bars are a sub-resolution auxiliary pattern. The scattering strip has the following advantages: firstly, the contour line width of a photoetching pattern can be sensed, the light intensity contrast is improved, and the edge placement error is reduced; secondly, the depth of focus is increased, thereby improving the photolithography process window.

The obtaining unit U3 is configured to obtain the configuration vector D, so as to perform optimization processing on the configuration vector D by the optimization processing unit U4, and prepare for obtaining an optimized configuration vector.

In the present embodiment, the arrangement vector D is constituted by the arrangement parameters (D, w) of a plurality of kinds of main patterns, and therefore, the arrangement vector D is represented by 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 subsequent optimization processing.

After the obtaining unit U3 obtains the configuration vector D, the configuration vector D has a corresponding relationship with the optimal focal plane offset. Specifically, the configuration vector D has a correspondence relationship with the optimal focal plane offset amount between the plurality of main patterns.

Each master pattern has a corresponding optimal focal plane. The optimal focal plane offset refers to: for a plurality of optimal focal planes corresponding to the plurality of main patterns respectively, the difference value between the maximum value and the minimum value in the plurality of optimal focal planes is the optimal focal plane offset between the plurality of main patterns, namely the optimal 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 optimal focal plane offset and the configuration vectors D, that is, when the configuration vectors D are assigned, for each configuration vector D, according to a certain rule F, there is a uniquely determined optimal focal plane offset corresponding to the configuration vector D.

In this embodiment, the obtaining unit U3 obtains a plurality of configuration parameters (D, w) corresponding to a plurality of main patterns to form the 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 subsequent optimization processing, so that the optimal focal planes of the plurality of main patterns during lithography can be considered, and when an optimal configuration vector is obtained after the subsequent optimization processing, the optimal focal plane offset between the plurality of main patterns can be minimized correspondingly, and a maximized common process window of the lithography process can be obtained.

Specifically, the smaller the offset of the optimal focal plane between the main patterns of different types is, the closer the optimal focal plane of the main patterns of different types is, and accordingly, the larger the common focal depth between the main patterns of different types is, the larger the common process window of the photolithography is.

The optimization processing unit U4 optimizes the configuration vector D based on the corresponding relationship between the configuration vector D and the optimal focal plane offset to obtain the optimized configuration vector D corresponding to the minimum optimal focal plane offset_opt。

The optimization processing unit U4 is configured to perform optimization processing on the configuration vector D to obtain an optimized configuration vector D_optThus optimizing the configuration vector D_optThe data is output to the configuration unit U5.

The optimization processing unit U4 optimizes the configuration vector D by obtaining the optimal configuration vector D corresponding to the minimum best focal plane offset_optAnd thus at configuration unit U5 according to said optimized configuration vector D_optCorresponding configuration parameters are set around the main pattern, so as to ensure the best focus between different kinds of main patterns in the photoetching process after setting the auxiliary patternThe plane offset is small, the optimal focal planes among the main patterns of different types are relatively close, and correspondingly, the common focal depth among the main patterns of different types is also large, so that the maximized common process window of the photoetching process is favorably obtained.

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, the optimal focal plane offset when a partial derivative of the function f (D) with respect to the configuration vector D is zero, and the corresponding optimal configuration vector D_opt. That is, when 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, the corresponding optimal configuration vector D is obtained_opt(as shown in formula (III) in the previous embodiment).

When the function f (D) of the optimum focal plane offset is zero with respect to the partial derivative of the configuration vector D, the function f (D) of the optimum focal plane offset converges accordingly, that is to say the optimum focal plane offset D accordingly attains a minimum value.

Specifically, in practical operation, the optimization processing unit U4 is configured to obtain, by using a gradient algorithm, a function f (D) of the optimal focal plane offset, where a difference between a gradient vector of the configuration vector D and zero is within a preset Threshold (Threshold), and a corresponding optimized configuration vector D_opt。

The preset threshold range is not too small or too large. If the preset threshold range is too small, the speed of the optimization processing unit U4 for performing optimization processing is easily too low, and the processing efficiency of the optimization processing unit U4 is easily reduced; if the preset threshold range is too large, it is easy to cause the optimization processing unit U4 to perform incomplete optimization processing, for example: the optimal focal plane offset corresponding to the optimized configuration vector obtained by the optimization processing unit U4 may not be the minimum value. For this reason, in this embodiment, the preset threshold range is 10^-5To 10^-1For example: the preset threshold range is 0.001, 0.0001 and the like.

In this embodiment, the optimization processing unit U4 includes: initial setting unitU41 for setting an initial configuration vector D₀With said initial configuration vector D₀As a configuration vector D to be optimized_i(ii) a A search unit U42 for searching along the direction of the gradient vector corresponding to the configuration vector to be optimized to obtain the optimized configuration vector D corresponding to the minimum best focal plane offset_opt。

The initial setting unit U41 is used for searching the unit U42 along the configuration vector D to be optimized_iA corresponding gradient vector direction search is prepared.

In this embodiment, the configuration vector D to be optimized_iDetermined by the formula (iv) in the previous embodiment. Wherein i is a positive integer from 0 to N. When i is 0, the configuration vector D to be optimized_iFor initial configuration of vector D₀。

The search unit U42 is used to follow the configuration vector D to be optimized_iSearching the direction of the corresponding gradient vector to obtain the optimal configuration vector D corresponding to the minimum optimal focal plane offset_opt。

Specifically, in this embodiment, the search unit U42 is configured to obtain the optimal configuration vector D corresponding to the difference between the gradient vector and zero within the aforementioned preset threshold range_opt。

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 the steepest descent method to obtain the optimized configuration vector D corresponding to the minimum optimal focal plane offset_opt. The steepest descent method descends along the direction of the negative gradient, so as to obtain the corresponding optimal configuration vector D when the difference value between the gradient vector and zero is within the preset threshold range_optThen, obtaining the optimized configuration vector D_optCorresponding minimum best focal plane offset.

In other embodiments, the search unit is further configured to search along the direction of the gradient vector by a conjugate gradient method or other search algorithms, and obtain the corresponding optimal configuration vector when the gradient vector is zero.

In this embodiment, the search unit U42 includes: a calculating subunit U421 for calculating the configuration vector D to be optimized_iSetting a variation quantity Delta D_iAnd according to said variation quantity DeltaD_iObtaining said optimal focal plane offset with respect to a configuration vector D to be optimized_iThe gradient vector of (a); a judgment subunit U422 for judging the configuration vector D to be optimized_iWhether the difference value of the corresponding gradient vector and zero is within a preset Threshold value (Threshold) range; when it is associated with the configuration vector D to be optimized_iWhen the difference between the corresponding gradient vector and zero is within the preset threshold range, the determining subunit U422 is configured to use the configuration vector D to be optimized_iOutput to a completion subunit U423, the completion subunit U423 being configured to optimize the configuration vector D to be optimized_iAs said optimized configuration vector D_opt(ii) a When it is associated with the configuration vector D to be optimized_iWhen the difference between the corresponding gradient vector 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 output the configuration vector to be optimized according to the variation Δ D_iUpdating the configuration vector D to be optimized_iAnd returns to the calculation 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, the configuration vector D to be optimized is_iSetting a variation quantity Delta D_iThen, the calculating subunit U421 is used to obtain the variation Δ D_iObtaining a configuration vector D to be optimized according to the variation quantity DeltaF (D) of the optimal focal plane offset and dividing the variation quantity DeltaF (D) of the optimal focal plane offset by the variation quantity DeltaD_iCorresponding gradient vector

Specifically, the calculation subunit U421 is configured to calculate partial derivatives of the optimal focal plane offset with respect to each of the components, respectively, as gradient components in a direction corresponding to each of the components, where a plurality of gradient components in the directions corresponding to a plurality of the components constitute the gradient vector.

The determining subunit U422 is configured to determine whether a difference between a 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 the difference values between the multiple gradient components of the gradient vector and zero are all within the preset threshold range; when the difference values of the gradient components of the gradient vector and zero are all within the preset threshold range, outputting the configuration vector to be optimized to a completion subunit U423; and when the difference value of at least one component in the gradient vector and zero is not within the preset threshold range, entering a return subunit U424.

When the configuration vector D to be optimized_iWhen the difference value between the corresponding gradient vector and zero is within the preset threshold value range, the function of the optimal focal plane offset is converged, the minimum value of the optimal focal plane offset BFS is correspondingly obtained, and the sub-unit is completed by a configuration vector D to be optimized_iAs an optimized configuration vector D_opt。

When the judging subunit U422 judges the configuration vector D to be optimized_iWhen the difference between the corresponding gradient vector 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 U422 is configured to update the configuration vector to be optimized according to the variation and return to the calculating subunit U421.

The return subunit U424 returns the signal by a variation Δ D according to the variation_iUpdating the to-be-optimizedThe configuration vector is returned to the calculation subunit U421, i.e. the search continues along the direction of the gradient vector corresponding to the configuration vector to be optimized, until the configuration vector D to be optimized is obtained_iWhen the difference value between the corresponding gradient vector and zero is within the preset threshold value range, the corresponding optimized configuration vector D_opt。

In this embodiment, the return subunit U424 is configured to optimize the configuration vector D according to the configuration vector D to be optimized_iAnd amount of change Δ D_iObtaining an updated configuration vector D_i+1And with the updated configuration vector D_i+1Replacing a configuration vector D to be optimized_i。

In particular, the return subunit U424 is configured to utilize the configuration vector D to be optimized_iPlus a variation DeltaD_iObtaining the updated configuration vector D_i+1。

The configuration unit U5 is configured to configure the vector D according to the optimization_optAnd arranging auxiliary graphs around the main graph according to the plurality of configuration parameters.

Optimized configuration vector D_optCorresponding to the minimum optimal focal plane offset or the maximum common focal depth between the main patterns of multiple types, thereby configuring the vector D according to the optimization_optAfter the auxiliary patterns are arranged around the main patterns, the optimal focal plane offset between the main patterns of different types is small during photoetching, namely, the optimal focal planes of the main patterns of different types are relatively close, and correspondingly, the overlapping parts of the focal depths of the main patterns of different types are maximized, so that the common process window of the photoetching process is favorably increased.

Correspondingly, the invention also provides a mask plate, which comprises: a plurality of main patterns and auxiliary patterns positioned around the main patterns, the auxiliary patterns being set by the optical proximity correction method of the foregoing embodiment.

The mask is used as a mask to expose photoresist on the wafer so as to form a photoresist pattern of each chip area on the wafer, and the photoresist pattern can be used for etching the chip area of the wafer and forming semiconductor structures such as a grid electrode, a metal interconnection line or a conductive plug and the like in the chip area of the wafer.

According to the embodiment, after the auxiliary patterns are arranged by adopting the optical proximity correction method of the embodiment, 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, so that when photoetching is carried out, the mask plate of the embodiment of the invention is favorable for maximizing the common process window of the photoetching process, and the pattern transfer precision is correspondingly improved.

The embodiment of the present invention further provides an apparatus, which can implement the optical proximity correction method provided by the embodiment of the present invention by loading the above optical proximity correction method in the form of a program. An optional hardware structure of the terminal device provided in the embodiment of the present invention may be as 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 mutual communication 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.

Processor 01 may be a central processing unit CPU, or an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits configured to implement an embodiment of the invention.

The memory 03 may comprise a high-speed RAM memory and may further comprise a non-volatile memory, such as at least one disk memory.

The memory 03 stores one or more computer instructions, which 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 above terminal device may further include other devices (not shown) that may not be necessary for the disclosure of the embodiment of the present invention; these other components may not be necessary to understand the disclosure of embodiments of the present invention, which are not individually described herein.

Embodiments of the present invention also provide a storage medium, where one or more computer instructions are stored, where the one or more computer instructions are used to implement the optical proximity correction method provided by the embodiments of the present invention.

The optical proximity correction method provided in the embodiment of the present invention obtains configuration parameters of each of the main patterns when performing optical proximity correction, where multiple configuration parameters corresponding to multiple main patterns are used to form a configuration vector, the configuration vector has a corresponding relationship with an optimal focal plane offset, and performs optimization processing on the configuration vector based on the corresponding relationship between the configuration vector and the optimal focal plane offset to obtain an optimized configuration vector corresponding to a minimum optimal focal plane offset, and then sets an auxiliary pattern around the main pattern according to the multiple configuration parameters corresponding to the optimized configuration vector, so as to be beneficial to ensuring that after the auxiliary pattern is set around the main pattern, the optimal focal plane offset between different types of main patterns is small, that is, the optimal focal planes corresponding to different types of main patterns are relatively close, the focal depth overlap between the different kinds of main patterns is maximized, thereby facilitating obtaining a maximized common process window of the photolithography process.

The embodiments of the present invention described above are combinations of elements and features of the present invention. Unless otherwise mentioned, the elements or features may be considered optional. Each element or feature may be practiced without being combined with other elements or features. In addition, the embodiments of the present invention may be configured by combining some elements and/or features. The order of operations described in the embodiments of the present invention may be rearranged. Some configurations of any embodiment may be included in another embodiment, and may be replaced with corresponding configurations of the other embodiment. It is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be combined into an embodiment of the present invention or may be included as new claims in a modification after the filing of the present application.

Embodiments of the invention may be implemented by various means, such as hardware, firmware, software, or a combination thereof. In a hardware configuration, the method according to an exemplary embodiment 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, micro-controllers, microprocessors, and the like.

In a firmware or software configuration, embodiments of the present invention may be implemented in the form of modules, procedures, functions, and the like. The software codes may be stored in memory units and executed by processors. The memory unit is located inside or outside the processor, and may transmit 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 effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

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 formed 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 pattern, wherein a plurality of configuration parameters corresponding to a plurality of main patterns 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 arranging auxiliary graphs around the main graph according to a plurality of configuration parameters corresponding to the optimized configuration vectors.

2. The method of claim 1, wherein the configuration vector is optimized using a gradient algorithm.

3. The method of claim 2, wherein the step of optimizing the configuration vector using a gradient algorithm comprises: and obtaining the corresponding optimized 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 method for optical proximity correction according to claim 2, wherein a gradient algorithm is used to obtain a gradient vector of the optimal focal plane offset with respect to the configuration vector, and when a difference between the gradient vector and zero is within a preset threshold, the corresponding optimal configuration vector is obtained.

5. The method of claim 4, wherein the predetermined threshold range is 10^-5To 10^-1。

6. The method of optical proximity correction according to 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 optimized configuration vector corresponding to the minimum optimal focal plane offset.

7. The method for optical proximity correction according to claim 6, wherein the optimal configuration vector corresponding to the smallest optimal focal plane offset is obtained by searching along the direction of the gradient vector corresponding to the configuration vector to be optimized using the steepest descent method or conjugate gradient method.

8. The method for optical proximity correction according to claim 6, wherein the step of searching along the direction of the gradient vector corresponding to the configuration vector to be optimized to obtain the optimized configuration vector corresponding to the smallest best focal plane offset 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;

when the difference value between the gradient vector corresponding to the configuration vector to be optimized and zero is within a preset threshold range, finishing 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 within a preset threshold range, updating the configuration vector to be optimized according to the variable quantity.

9. The method for optical proximity correction according to claim 8, wherein a variation is set for the configuration vector to be optimized, and a gradient vector of the optimal focal plane offset with respect to the configuration vector to be optimized is obtained by a finite difference method according to the variation.

10. The method of claim 8, wherein the step of updating the configuration vector to be optimized according to the variance comprises: and obtaining an updated configuration vector according to the configuration vector to be optimized and the variable quantity, and replacing the configuration vector to be optimized with the updated configuration vector.

11. The method of claim 8, wherein a plurality of predetermined distances and a plurality of predetermined widths respectively constitute components of the configuration vector;

the step of obtaining a gradient vector of the optimal focal plane offset with respect to the configuration vector to be optimized comprises: on the basis of the configuration vector to be optimized, calculating partial derivatives of the optimal focal plane offset relative to each component respectively, wherein the partial derivatives are used as gradient components in the direction corresponding to each component, and the gradient components in the directions corresponding to the components form the gradient vector.

12. The method of claim 1, wherein the auxiliary pattern comprises a scattering bar.

13. The method for correcting optical proximity of claim 1, wherein the main pattern is a pattern including a long bar 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 region including a plurality of main patterns;

the preset unit is used for providing a corresponding preset auxiliary graph around the main graph, the preset auxiliary graph has a preset width, a preset distance is reserved 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;

the acquisition unit is used for acquiring the configuration parameters of each main pattern, a plurality of configuration parameters corresponding to a plurality of main patterns are used for forming a configuration vector, and the configuration vector has a corresponding relation with the optimal focal plane offset;

the optimization processing unit is used for 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 the configuration unit is used for setting an auxiliary graph around the main graph 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 optimized 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 calculation subunit is configured to set a variation to the configuration vector to be optimized, and obtain a gradient vector of the optimal focal plane offset with respect 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 range, the judging subunit is used for outputting the configuration vector to be optimized to a completing subunit, and the completing subunit is used for taking the configuration vector to be optimized as the optimized configuration vector;

when the judging subunit judges that the difference between the gradient vector corresponding to the configuration vector to be optimized and zero is not within the preset threshold range, the judging subunit is configured to output the configuration vector to be optimized to a returning subunit, and the returning subunit is configured to update the configuration vector to be optimized according to the variation and return the configuration vector to the calculating subunit.

17. A reticle, comprising: a plurality of primary patterns and auxiliary patterns positioned around the primary patterns, the auxiliary patterns being provided by the optical proximity correction method of any one of claims 1-13.

18. An apparatus 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 one of claims 1-13.

19. A storage medium having stored thereon one or more computer instructions for implementing the method of optical proximity correction according to any of claims 1-13.