CN112015045B - Mask optimization method and electronic equipment - Google Patents
Mask optimization method and electronic equipment Download PDFInfo
- Publication number
- CN112015045B CN112015045B CN202010901995.4A CN202010901995A CN112015045B CN 112015045 B CN112015045 B CN 112015045B CN 202010901995 A CN202010901995 A CN 202010901995A CN 112015045 B CN112015045 B CN 112015045B
- Authority
- CN
- China
- Prior art keywords
- virtual contour
- mask
- evaluation point
- contour line
- main
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000005457 optimization Methods 0.000 title claims abstract description 44
- 238000011156 evaluation Methods 0.000 claims abstract description 118
- 238000003860 storage Methods 0.000 claims description 11
- 238000013459 approach Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 11
- 238000013461 design Methods 0.000 abstract description 4
- 230000000875 corresponding effect Effects 0.000 description 22
- 230000006870 function Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 15
- 230000003287 optical effect Effects 0.000 description 9
- 238000004590 computer program Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 7
- 238000012937 correction Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 229920002120 photoresistant polymer Polymers 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 238000012634 optical imaging Methods 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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)
- Preparing Plates And Mask In Photomechanical Process (AREA)
Abstract
The present application relates to the field of integrated circuit mask design, and in particular, to a mask optimization method and an electronic device. The method comprises the following steps: s1, breaking edges of a mask pattern to obtain an optimized region; s2, correspondingly forming a first virtual contour line in each corner region; s3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side; and S4, optimizing the mask until the objective function converges, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side, so that the obtained virtual contour is closer to the actual contour of the exposure pattern, and placing the evaluation point on the virtual contour and the EPE in the determined moving direction of the evaluation point can well reflect the mask optimization requirement, thereby achieving a better optimization effect.
Description
[ field of technology ]
The present application relates to the field of integrated circuit mask design, and in particular, to a mask optimization method and an electronic device.
[ background Art ]
Photolithography is a central step in integrated circuit fabrication and its purpose is to transfer the pattern on the mask through an optical imaging system to a photoresist coated on a silicon-based substrate and further to a silicon wafer. The pattern transferred onto the photoresist is called aerial image, AI (Aerial Image); the pattern transferred onto the silicon wafer is called a resist image, RI (Resist Image). For convenience of the following description, these two images will be collectively referred to as exposure patterns. Because of the diffraction effect of the optical imaging system, the high-order diffraction light cannot participate in imaging through the photoetching projection objective, so that the exposure pattern is deformed, and particularly when the feature size of the mask pattern is small, the exposure pattern cannot be distinguished. This phenomenon is called optical proximity effect (Optical Proximity Effect). To improve the imaging resolution and imaging quality, correction of the above-described optical proximity effect, i.e., OPC (Optical Proximity Correction), can be achieved by optimizing the mask pattern. OPC is generally divided into two steps: the first step is to break all sides of the mask pattern into a series of small line segments, and the second step is to make offset correction to the broken line segments. There are two methods of offsetting the main stream: the first method is to classify the broken small line segments according to the relative position, relative direction and other characteristics of the small line segments adjacent to the small line segments in the length direction, and establish an offset rule table, wherein each line segment is offset according to the offset rule defined by the table, which is called as rule-based optical proximity effect correction (RB-OPC); the second method is to calculate the predicted exposure pattern by using a photoetching imaging model, and calculate the offset value of each small line segment according to the difference inversion of the predicted exposure pattern and the ideal exposure pattern; the inversion process is iterated until the difference between the predicted exposure pattern and the ideal exposure pattern is small enough, which is known as model-based optical proximity correction (MB-OPC).
The goal of OPC is to make the difference between the predicted exposure pattern and the ideal exposure pattern small enough. The difference is measured by placing evaluation points on small line segments broken by the design mask pattern, determining the moving direction of the evaluation points, and calculating the edge placement error (EPE, edge Placement Error) of the evaluation points along the moving direction. Whether RB-OPC or MB-OPC, it is necessary to control EPE at all evaluation points within a certain range. The position and the evaluation moving direction of the evaluation point are preconditions for calculating the evaluation point EPE, and the EPE cannot accurately represent the difference between the predicted exposure pattern and the ideal exposure pattern due to unreasonable placement of the evaluation point or deviation of the evaluation moving direction from the gradient moving direction of the exposure pattern at the evaluation point, so that optimization fails. Therefore, how to set the evaluation points according to the mask pattern and determine the moving direction of the evaluation points will become a relatively important task for mask optimization.
[ application ]
The application provides a mask optimization method and electronic equipment, and aims to solve the technical problems that the position of an evaluation point in the mask optimization process and the moving direction of the determination evaluation point are deviated at present.
In order to solve the technical problems, the application provides a technical scheme that: a mask optimization method comprising the steps of: s1, providing a mask layout comprising a mask pattern, and breaking edges of the mask pattern to obtain an optimized region, wherein the optimized region at least comprises a main edge and side edges formed at two ends of the main edge, the side edges at two ends are positioned at two sides of the main edge, and the main edge and the two connected side edges form two angle-shaped regions; s2, correspondingly forming a first virtual contour line in each corner region, wherein each first virtual contour line is respectively an arc tangent to the main side and the corresponding side; and S3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side.
Preferably, the optimization method of the mask further comprises the steps of: s4, setting an objective function, optimizing the mask according to the placement position of the evaluation point and the moving direction of the evaluation point until the objective function converges in the step S2, and forming a first virtual contour line by the following steps: two tangent points are respectively set on one main edge and one tangent point is respectively set on two side edges corresponding to the main edge, and the first virtual contour line passes through the tangent points of the side edges and the main edge, which are close to the corresponding angle areas.
Preferably, the lengths of the tangent sections of the virtual contour line and one side edge and the main edge are defined as r1 and r2, and the lengths of the tangent sections of the virtual contour line and the other side edge and the main edge are defined as r3 and r4; in the step S3, if the sum of the lengths of the tangent lines formed by the main sides of each virtual contour is smaller than or equal to the length of the main side, an evaluation point is directly set on the first virtual contour line, otherwise, the main sides are adjusted to form a second virtual contour line, so as to set the evaluation point on the second virtual contour line and determine the moving direction of the evaluation point.
Preferably, in the step S3, the adjusting the main edge to form the second virtual contour specifically includes the following steps: s31, moving two vertexes of the main edge to a distance in a direction close to a side edge tangent point to obtain a new vertex, and connecting the two new vertexes to obtain an adjusted main edge; and S32, forming a second virtual contour line according to the adjusted main edge, placing an evaluation point on the second virtual contour line and determining the moving direction of the evaluation point.
Preferably, in the step S31, a distance that the two vertexes of the main edge move in a direction approaching the side tangent point is obtained by: the distance moved by the vertex corresponding to r1 is:the distance moved by the vertex corresponding to r3 is: />Wherein d is the length of the main side, alpha and beta are adjusting coefficients, and the numerical range is 1-2.
Preferably, the specific operation in the step S32 is as follows: setting a division point at the midpoint of the adjusted main edge or according to the proportional relation of r2 and r4, so that the newly formed second virtual contour line passes through the corresponding tangent point and the division point of one side edge respectively.
Preferably, if said d/(r) 2 +r 3 ) And when the temperature approaches zero, the numerical value of the alpha and the beta is 1.
Preferably, one or more parameters of r1, r2, r3, r4, α, β are adjusted according to the convergence of the objective function.
Preferably, the normal direction at the evaluation point is the moving direction of the evaluation point.
In order to solve the technical problem, the application also provides electronic equipment, which comprises one or more processors; and a storage means for storing one or more programs that, when executed by the one or more processors, cause the one or more processors to implement a mask optimization method as described above that ensures adequate contact of the mask image with the via image.
Compared with the prior art, the mask optimization method comprises the following steps:
s1, providing a mask layout comprising a mask pattern, and breaking edges of the mask pattern to obtain an optimized region, wherein the optimized region at least comprises a main edge and side edges formed at two ends of the main edge, and the main edge and the two connected side edges form two angle-shaped regions, wherein the included angle of one angle-shaped region is larger than 180 degrees, and the other angle-shaped region is smaller than 180 degrees; s2, correspondingly forming a first virtual contour line in each corner region, wherein each first virtual contour line is respectively an arc tangent to the main side and the corresponding side; s3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side; and S4, setting an objective function, optimizing the mask according to the placement position of the evaluation point and the moving direction of the evaluation point until the objective function is converged, and determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side aiming at the situation that an optimization area is Z-shaped, so that the obtained virtual contour is closer to the actual contour of an exposure pattern, and the placement of the evaluation point on the virtual contour and the EPE in the determined moving direction of the evaluation point can well reflect the mask optimization requirement, thereby achieving a good optimization effect.
Defining the lengths of tangential sections of one virtual contour line and one side edge and the main edge as r1 and r2 respectively, and the lengths of tangential sections of the other virtual contour line and the other side edge and the main edge as r3 and r4 respectively; in the step S3, if the sum of the lengths of the cut lines formed by the main edge of each virtual contour is smaller than or equal to the length of the main edge, an evaluation point is directly set on the first virtual contour line, otherwise, the main edge is adjusted to form a second virtual contour line, so that the evaluation point is set on the second virtual contour line, and the moving direction of the evaluation point is determined, when the sum of the lengths of the cut lines formed by the main edge of each virtual contour is greater than the length of the main edge, the initially formed first virtual contour line is generally poor in stability, has a larger difference from the actual contour line of the exposure pattern, the second virtual contour line formed after the main edge is adjusted is smoother, and a better optimization effect can be obtained by placing the evaluation point on the second virtual contour line.
[ description of the drawings ]
FIG. 1 is a flow chart of a mask optimizing method in a first embodiment of the application;
FIG. 2 is a schematic diagram of a mask layout provided in a first embodiment of the present application;
FIG. 3A is a schematic diagram of the first embodiment of the present application when dividing the mask pattern into I-type regions;
fig. 3B is a schematic view of the first embodiment of the present application when dividing the mask pattern into L-shaped areas;
fig. 3C is a schematic diagram of the first embodiment of the present application when dividing the mask pattern into U-shaped areas;
FIG. 3D is a schematic diagram of the first embodiment of the present application when dividing the mask pattern into Z-shaped areas;
fig. 4A is a schematic diagram of a virtual contour line corresponding to an I-type region and evaluation points and movement directions of the evaluation points disposed on the virtual contour line in the first embodiment of the present application;
fig. 4B is a schematic diagram of a virtual contour line corresponding to an L-shaped area and evaluation points and movement directions of the evaluation points provided on the virtual contour line in the first embodiment of the present application;
fig. 4C is a schematic diagram of a virtual contour line corresponding to a U-shaped region and evaluation points and movement directions of the evaluation points disposed on the virtual contour line in the first embodiment of the present application;
fig. 4D is a schematic diagram of a virtual contour line corresponding to a "Z" type region and evaluation points and movement directions of the evaluation points provided on the virtual contour line in the first embodiment of the present application;
FIG. 5 is a schematic view of a first virtual contour formed by a "Z" shaped region in a first embodiment of the application;
FIG. 6 is a schematic view of a first virtual contour line formed by each virtual contour in the first embodiment of the application when the sum of the lengths of the tangent lines formed by the main sides is greater than the length of the main sides;
FIG. 7 is a detailed flowchart of the second virtual contour formed in step S3 in the first embodiment of the present application;
FIG. 8 is a graph showing the difference between the front and rear of the main edge of the Z-shaped region according to the first embodiment of the present application;
fig. 9 is a schematic view of a second virtual contour line formed by adjusting a main edge by a Z-shaped area and shows evaluation points and a moving direction of the evaluation points arranged on the second virtual contour line according to the first embodiment of the present application;
fig. 10 is a schematic block diagram of an electronic device provided in a second embodiment of the present application.
FIG. 11 is a schematic diagram of a computer system suitable for use in implementing embodiments of the present application.
[ detailed description ] of the application
For the purpose of making the technical solution and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
Referring to fig. 1, a first embodiment of the present application provides a mask optimization method, which includes the following steps:
s1, providing a mask layout comprising a mask pattern, and breaking edges of the mask pattern to obtain an optimized region, wherein the optimized region at least comprises a main edge and side edges formed at two ends of the main edge, the side edges at two ends are positioned at two sides of the main edge, and the main edge and the two connected side edges form two angle-shaped regions;
referring to fig. 2, in this step, the mask pattern is a rectangular structure, typically a rectangular block structure, which corresponds to the region M in fig. 2. In some other embodiments, the mask pattern may be other shapes, depending primarily on the particular shape of the original mask, such as trapezoidal, irregular polygonal, regular polygonal, and the like.
Referring to fig. 3A, 3B, 3C and 3D, a plurality of dividing points are provided at the edge of the mask pattern M to break the edge of the mask pattern M, so as to obtain different types of optimized regions. Typically, four types are formed after breaking, including an I-shape, an L-shape, a U-shape, and a "Z" shape. According to the optimization areas with different shapes, the evaluation points are required to be set in different modes, and the moving direction of the evaluation points is required to be set, so that a more ideal optimization result can be obtained.
The imaged contour of the angular region in the mask will be an arc due to the high frequency filtering effect of the lithographic projection objective system. Before placing the evaluation points, virtual contour lines of four types of areas are generated first. For the I-shaped region, the virtual contour coincides with itself; for L-shaped, U-shaped, and Z-shaped regions, the virtual contour is a fitted curve that passes through a particular point and is tangent to or cuts a particular angle from the line segment where the particular point is located, a second or higher number of times. The evaluation point is placed at a certain position on the virtual contour line, and the evaluation point moving direction is the normal direction of the virtual contour line at the evaluation point. Minimizing the EPE of the evaluation point along the direction of movement of the evaluation point is the target of OPC optimization. Edge placement error (Edge Placement Error, EPE) is the difference between the edge of the exposed photoresist pattern and the design pattern as simulated by the lithography software.
Virtual contour lines corresponding to four types of regions in fig. 4A, 4B, 4C, and 4D, evaluation points thereon, and evaluation point moving directions. The evaluation points and the movement direction of the evaluation points obtained by the method have good predictability for I-shaped, L-shaped and U-shaped areas, and the EPE of the evaluation points of the three areas along the movement direction of the evaluation points can also well reflect the requirement of OPC optimization, so that OPC optimization is converged. However, for the Z-shaped area, the evaluation point obtained by the method may be far away from the actual contour line of the predicted exposure pattern, and the EPE of the evaluation point in the moving direction of the evaluation point cannot accurately reflect the difference between the predicted exposure pattern and the ideal exposure pattern, so that the OPC optimization is not converged or the OPC optimization result is not controllable due to the minimization of the EPE. Therefore, the optimized region described in the above step S1 corresponds to the case of the "Z" shape.
Referring again to fig. 1, the mask optimizing method further includes the following steps:
s2, correspondingly forming a first virtual contour line in each corner region, wherein each first virtual contour line is respectively an arc tangent to the main side and the corresponding side. In this step, a first virtual contour is formed by:
two tangent points are respectively set on one main edge and one tangent point is respectively set on two side edges corresponding to the main edge, and the first virtual contour line passes through the tangent points of the side edges and the main edge, which are close to the corresponding angle areas.
Referring to fig. 5, two vertexes of the main edge are a and B respectively, two tangential points set at two sides are C and F respectively, and two tangential points set at the main edge are D and E respectively, wherein the tangential point D is close to the vertex a and the tangential point E is close to the vertex B. The lengths of the tangent sections of the virtual contour line and one side edge and the main edge are defined as r1 and r2 respectively, namely the lengths of the tangent sections AC and AD in the corresponding graph respectively, and the lengths of the tangent sections of the other virtual contour line and the other side edge and the main edge are defined as r4 and r3 respectively, namely the lengths of the tangent sections BF and BE in the corresponding graph respectively.
It should be noted that, typically, the initial r1, r2, r3, and r4 are set manually, that is, by the user for the accuracy of mask optimization. In the subsequent optimization process, proper adjustment can be performed according to the optimization result, so that a better optimization result is obtained.
Referring again to fig. 1, the mask optimizing method further includes the following steps:
and S3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side.
In this step, if the sum of the lengths of the tangent lines formed by the main sides of each virtual contour is smaller than or equal to the length of the main side, an evaluation point is directly set on the first virtual contour line, otherwise, the main sides are adjusted to form a second virtual contour line, so that an evaluation point is set on the second virtual contour line, and the moving direction of the evaluation point is determined.
Optionally, the length of the main edge AB is denoted by d, i.e. when r2+r3+.d, an evaluation point is set directly on the first virtual contour; when r2+r3 > d, the main edge needs to be adjusted to form a second virtual contour line, so as to set an evaluation point on the second virtual contour line and determine the movement direction of the evaluation point. As shown in fig. 5, the circular arcs CD and EF correspond to the first virtual contour lines of the two angular regions, respectively. In the setting of the evaluation points, one or more evaluation points may be set on the first virtual contour line, and the plurality of evaluation points may be set in an equidistant manner. The normal direction at the evaluation point is the moving direction of the evaluation point.
Referring to fig. 6, the case where the sum of the lengths of the tangent lines formed by the main sides is greater than the length of the main sides, that is, r2+r3 > d, is shown in the figure, and the main sides need to be adjusted to form new virtual contour lines.
Referring to fig. 7, when r2+r3 > d, the adjusting the main edge to form the second virtual contour specifically includes the following steps:
s31, moving two vertexes of the main edge to a distance in a direction close to a side edge tangent point to obtain a new vertex, and connecting the two new vertexes to obtain an adjusted main edge; and
S32, forming a second virtual contour line according to the adjusted main edge, placing an evaluation point on the second virtual contour line, and determining the moving direction of the evaluation point.
Referring to fig. 8 and 9, in the above step S31, the vertex a moves a distance in the direction of the tangent point C to obtain a ', the vertex B ' moves a distance in the direction of the tangent point F to obtain B ', and the adjusted main edge a ' B ' is obtained by connecting the vertex a ' and the vertex B '.
The distance that the two vertexes of the main edge move towards the direction close to the side tangent point is obtained by the following method:
the distance moved by the vertex corresponding to r1 is:
the distance moved by the vertex corresponding to r3 is:
wherein alpha and beta are regulating coefficients, and the numerical range is 1-2.
With continued reference to fig. 9, in step S32, a dividing point is set at the midpoint of the adjusted main edge or according to the ratio of r2 to r4, so that the newly formed second virtual contour line passes through the corresponding cutting point and dividing point of one side edge respectively. The O-point in the figure is the tangent point of the main edge through which the second virtual contour line needs to pass. The arcs CO, FO in the figure are the arcs of the second virtual contour. Compared with the arcs CD and EF in FIG. 8, the radians of the second virtual contour lines CO and FO are obviously more gentle and are closer to the actual contour line of the predicted exposure pattern, and the EPE obtained by setting evaluation points on the second virtual contour lines and calculating along the moving direction of the evaluation points can also reflect the difference between the predicted exposure pattern and the ideal exposure pattern more accurately.
In the actual optimization process, r1, r2, r3 and r4 can be adjusted according to the optimization result, and alpha and beta can be adjusted. Optionally, one or more parameters of r1, r2, r3, r4, α, β may be adjusted.
In some embodiments, if d/(r) 2 +r 3 ) And when the temperature approaches zero, the numerical value of the alpha and the beta is 1.
Referring again to fig. 1, the mask optimizing method further includes the following steps:
and S4, setting an objective function, and optimizing the mask according to the placement position of the evaluation point and the moving direction of the evaluation point until the objective function is converged.
The objective function is a function of the edge placement error EPE, which is as follows:
in the actual optimization calculation process, EPEs of adjacent evaluation points are correlated with each other. One of the evaluation points moves necessarily resulting in a change in the neighboring evaluation points EPE, and the final objective of the optimization needs to be such that the EPE of the whole mask image is minimal. Wherein x is the corresponding evaluation point, EPE x Refers to EPE at the evaluation point, and the summation refers to the summation of EPE at all evaluation points on the mask pattern to be extremely small, and the mask is considered to beThe optimization reaches convergence. The parameters r1, r2, r3, r4, α, β are adjusted according to the values of the cost.
Referring to fig. 10, a second embodiment of the present application provides an electronic device 300, which includes one or more processors 301;
storage 302, for storing one or more programs,
the one or more programs, when executed by the one or more processors 301, cause the one or more processors 301 to implement a mask optimization method that ensures adequate contact of a mask image with a via image as provided by the first embodiment.
Referring now to FIG. 11, there is illustrated a schematic diagram of a computer system 800 suitable for use in implementing a terminal device/server in accordance with an embodiment of the present application. The terminal device/server shown in fig. 11 is only an example, and should not impose any limitation on the functions and scope of use of the embodiments of the present application.
As shown in fig. 11, the computer system 800 includes a Central Processing Unit (CPU) 801, which can perform various appropriate actions and processes according to a program stored in a Read Only Memory (ROM) 802 or a program loaded from a storage section 808 into a Random Access Memory (RAM) 803. In the RAM 803, various programs and data required for the operation of the system 800 are also stored. The CPU 801, ROM 802, and RAM 803 are connected to each other by a bus 804. An input/output (I/O) interface 805 is also connected to the bus 804.
The following components are connected to the I/O interface 805: an input portion 806 including a keyboard, mouse, etc.; an output portion 807 including a display such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), and a speaker; a storage section 808 including a hard disk or the like; and a communication section 809 including a network interface card such as a LAN card, a modem, or the like. The communication section 809 performs communication processing via a network such as the internet. The drive 810 is also connected to the I/O interface 805 as needed. A removable medium 811 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 810 as needed so that a computer program read out therefrom is mounted into the storage section 808 as needed.
The processes described above with reference to flowcharts may be implemented as computer software programs according to embodiments of the present disclosure. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method shown in the flowcharts. In such an embodiment, the computer program may be downloaded and installed from a network via the communication section 809, and/or installed from the removable media 811. The above-described functions defined in the method of the present application are performed when the computer program is executed by a Central Processing Unit (CPU) 801. The computer readable medium according to the present application may be a computer readable signal medium or a computer readable storage medium, or any combination of the two. The computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
Computer program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The units involved in the embodiments of the present application may be implemented in software or in hardware. As another aspect, the present application also provides a computer-readable medium that may be contained in the apparatus described in the above embodiments; or may be present alone without being fitted into the device.
Compared with the prior art, the mask optimization method comprises the following steps:
s1, providing a mask layout comprising a mask pattern, and breaking edges of the mask pattern to obtain an optimized region, wherein the optimized region at least comprises a main edge and side edges formed at two ends of the main edge, and the main edge and the two connected side edges form two angle-shaped regions, wherein the included angle of one angle-shaped region is larger than 180 degrees, and the other angle-shaped region is smaller than 180 degrees; s2, correspondingly forming a first virtual contour line in each corner region, wherein each first virtual contour line is respectively an arc tangent to the main side and the corresponding side; s3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side; and S4, setting an objective function, optimizing the mask according to the placement position of the evaluation point and the moving direction of the evaluation point until the objective function is converged, and determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side aiming at the situation that an optimization area is Z-shaped, so that the obtained virtual contour is closer to the actual contour of an exposure pattern, and the placement of the evaluation point on the virtual contour and the EPE in the determined moving direction of the evaluation point can well reflect the mask optimization requirement, thereby achieving a good optimization effect.
Defining the lengths of tangential sections of one virtual contour line and one side edge and the main edge as r1 and r2 respectively, and the lengths of tangential sections of the other virtual contour line and the other side edge and the main edge as r3 and r4 respectively; in the step S3, if the sum of the lengths of the cut lines formed by the main edge of each virtual contour is smaller than or equal to the length of the main edge, an evaluation point is directly set on the first virtual contour line, otherwise, the main edge is adjusted to form a second virtual contour line, so that the evaluation point is set on the second virtual contour line, and the direction of the evaluation point is determined, when the sum of the lengths of the cut lines formed by the main edge of each virtual contour is greater than the length of the main edge, the initially formed first virtual contour line is generally poor in stability, has a larger difference from the actual contour line of the exposure pattern, the second virtual contour line formed after the main edge is adjusted is more stable, and a better optimization effect can be obtained by placing the evaluation point on the second virtual contour line.
The above description is only of the preferred embodiments of the present application and is not intended to limit the application, but any modifications, equivalents, improvements, etc. within the principles of the present application should be included in the scope of the present application.
Claims (10)
1. A method of mask optimization comprising the steps of:
s1, providing a mask layout comprising a mask pattern, and breaking edges of the mask pattern to obtain an optimized region, wherein the optimized region at least comprises a main edge and side edges formed at two ends of the main edge, the side edges at two ends are positioned at two sides of the main edge, and the main edge and the two connected side edges form two angle-shaped regions;
s2, correspondingly forming a first virtual contour line in each corner region, wherein each first virtual contour line is respectively an arc tangent to the main side and the corresponding side;
and S3, determining the placement position of the evaluation point and the moving direction of the evaluation point according to the relation between the sum of the lengths of the tangent lines formed by each virtual contour on the main side and the sum of the lengths of the main side.
2. The mask optimizing method according to claim 1, characterized in that: the mask optimization method further comprises the following steps:
and S4, setting an objective function, and optimizing the mask according to the placement position of the evaluation point and the moving direction of the evaluation point until the objective function is converged.
In the step S2, a first virtual contour line is formed by:
two tangent points are respectively set on one main edge and one tangent point is respectively set on two side edges corresponding to the main edge, and the first virtual contour line passes through the tangent points of the side edges and the main edge, which are close to the corresponding angle areas.
3. The mask optimizing method according to claim 2, characterized in that: defining the lengths of tangential sections of one virtual contour line and one side edge and the main edge as r1 and r2 respectively, and the lengths of tangential sections of the other virtual contour line and the other side edge and the main edge as r3 and r4 respectively;
in the step S3, if the sum of the lengths of the tangent lines formed by the main sides of each virtual contour is smaller than or equal to the length of the main side, an evaluation point is directly set on the first virtual contour line, otherwise, the main sides are adjusted to form a second virtual contour line, so as to set the evaluation point on the second virtual contour line and determine the moving direction of the evaluation point.
4. A mask optimizing method as claimed in claim 3, characterized in that: in the step S3, the adjusting the main edge to form the second virtual contour specifically includes the following steps:
s31, moving two vertexes of the main edge to a distance in a direction close to a side edge tangent point to obtain a new vertex, and connecting the two new vertexes to obtain an adjusted main edge; and
S32, forming a second virtual contour line according to the adjusted main edge, placing an evaluation point on the second virtual contour line, and determining the moving direction of the evaluation point.
5. The mask optimizing method according to claim 4, wherein: in the step S31, the distance that the two vertices of the main edge move in the direction approaching the side tangent point is obtained by:
the distance moved by the vertex corresponding to r1 is:
the distance moved by the vertex corresponding to r3 is:
wherein d is the length of the main side, alpha and beta are adjusting coefficients, and the numerical range is 1-2.
6. A mask optimizing method as claimed in claim 3, characterized in that: the specific operation in step S32 is as follows:
setting a division point at the midpoint of the adjusted main edge or according to the proportional relation of r2 and r4, so that the newly formed second virtual contour line passes through the corresponding tangent point and the division point of one side edge respectively.
7. The mask optimizing method according to claim 5, characterized in that: if said d/(r) 2 +r 3 ) And when the temperature approaches zero, the numerical value of the alpha and the beta is 1.
8. The mask optimizing method according to claim 5, characterized in that: and adjusting one or more parameters of r1, r2, r3, r4, alpha and beta according to the convergence condition of the objective function.
9. The mask optimizing method according to any one of claims 1 to 8, characterized in that: the normal direction at the evaluation point is the moving direction of the evaluation point.
10. An electronic device, characterized in that: comprising one or more processors;
storage means for storing one or more programs,
the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the mask optimization method of any of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010901995.4A CN112015045B (en) | 2020-08-31 | 2020-08-31 | Mask optimization method and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010901995.4A CN112015045B (en) | 2020-08-31 | 2020-08-31 | Mask optimization method and electronic equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112015045A CN112015045A (en) | 2020-12-01 |
| CN112015045B true CN112015045B (en) | 2023-11-17 |
Family
ID=73516412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010901995.4A Active CN112015045B (en) | 2020-08-31 | 2020-08-31 | Mask optimization method and electronic equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112015045B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101751502A (en) * | 2008-12-18 | 2010-06-23 | 睿初科技公司 | Method and system for correcting window maximized optic proximity effect in photoetching process |
| CN101937171A (en) * | 2009-07-03 | 2011-01-05 | 中芯国际集成电路制造(上海)有限公司 | Method for building optical proximity correction model, optical proximity correction method and mask |
| JP2012014058A (en) * | 2010-07-02 | 2012-01-19 | Toppan Printing Co Ltd | Photomask evaluation system and method thereof |
| JP2012181298A (en) * | 2011-03-01 | 2012-09-20 | Dainippon Printing Co Ltd | Mask pattern correction method and program, and photomask using mask pattern correction method |
| CN105303588A (en) * | 2015-09-18 | 2016-02-03 | 中国航空工业集团公司沈阳发动机设计研究所 | Two-dimensional graph contour drawing method |
| WO2019012887A1 (en) * | 2017-07-14 | 2019-01-17 | 大日本印刷株式会社 | Shape correction device and shape correction method for graphical pattern |
| CN110716385A (en) * | 2018-07-13 | 2020-01-21 | 中芯国际集成电路制造(上海)有限公司 | Optical proximity correction method |
| CN110765724A (en) * | 2019-10-26 | 2020-02-07 | 东方晶源微电子科技（北京）有限公司 | Mask optimization method and electronic equipment |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7434199B2 (en) * | 2005-09-27 | 2008-10-07 | Nicolas Bailey Cobb | Dense OPC |
-
2020
- 2020-08-31 CN CN202010901995.4A patent/CN112015045B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101751502A (en) * | 2008-12-18 | 2010-06-23 | 睿初科技公司 | Method and system for correcting window maximized optic proximity effect in photoetching process |
| CN101937171A (en) * | 2009-07-03 | 2011-01-05 | 中芯国际集成电路制造(上海)有限公司 | Method for building optical proximity correction model, optical proximity correction method and mask |
| JP2012014058A (en) * | 2010-07-02 | 2012-01-19 | Toppan Printing Co Ltd | Photomask evaluation system and method thereof |
| JP2012181298A (en) * | 2011-03-01 | 2012-09-20 | Dainippon Printing Co Ltd | Mask pattern correction method and program, and photomask using mask pattern correction method |
| CN105303588A (en) * | 2015-09-18 | 2016-02-03 | 中国航空工业集团公司沈阳发动机设计研究所 | Two-dimensional graph contour drawing method |
| WO2019012887A1 (en) * | 2017-07-14 | 2019-01-17 | 大日本印刷株式会社 | Shape correction device and shape correction method for graphical pattern |
| CN110716385A (en) * | 2018-07-13 | 2020-01-21 | 中芯国际集成电路制造(上海)有限公司 | Optical proximity correction method |
| CN110765724A (en) * | 2019-10-26 | 2020-02-07 | 东方晶源微电子科技（北京）有限公司 | Mask optimization method and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112015045A (en) | 2020-12-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6194104B1 (en) | Optical proximity correction (OPC) method for improving lithography process window | |
| JP4192618B2 (en) | Mask correction method | |
| US6453457B1 (en) | Selection of evaluation point locations based on proximity effects model amplitudes for correcting proximity effects in a fabrication layout | |
| US6792590B1 (en) | Dissection of edges with projection points in a fabrication layout for correcting proximity effects | |
| US8372565B2 (en) | Method for optimizing source and mask to control line width roughness and image log slope | |
| US6763514B2 (en) | Method and apparatus for controlling rippling during optical proximity correction | |
| US7601471B2 (en) | Apparatus and method for correcting pattern dimension and photo mask and test photo mask | |
| US20030046653A1 (en) | Microloading effect correction | |
| US7673279B2 (en) | Iterative method for refining integrated circuit layout using compass optical proximity correction (OPC) | |
| US8473878B2 (en) | Lithographically enhanced edge determination | |
| JPH10104818A (en) | Method for correcting light proximity effect | |
| KR100988987B1 (en) | A pair of photo masks for measuring flare, flare measuring apparatus and flare measuring method | |
| US11281839B2 (en) | Method, apparatus and electronic device for photolithographic mask optimization of joint optimization of pattern and image | |
| JP2000098584A (en) | Correcting method of mask pattern and recording medium recording mask pattern correction program | |
| CN113495426A (en) | Optical proximity effect correction method and device | |
| CN112083631B (en) | Informatics calculation photoetching method | |
| CN109656093B (en) | Method for designing layout of photomask and method for manufacturing photomask | |
| JP2007324273A (en) | Simulation method, simulation system, and method of correcting mask pattern | |
| CN112015045B (en) | Mask optimization method and electronic equipment | |
| JP3576791B2 (en) | Mask pattern design method | |
| US6261724B1 (en) | Method of modifying a microchip layout data set to generate a predicted mask printed data set | |
| CN113050368A (en) | Optical proximity correction method and mask manufacturing method | |
| JPH11126824A (en) | Pattern designing method | |
| JP2011023549A (en) | Evaluation method for mask pattern, mask pattern correction method and mask pattern generator | |
| JP2006303175A (en) | Method for defining illumination brightness distribution |
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 | ||
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 100176 building 12, yard 156, Jinghai 4th Road, Beijing Economic and Technological Development Zone, Daxing District, Beijing Patentee after: Dongfang Jingyuan Microelectronics Technology (Beijing) Co.,Ltd. Address before: 100176 building 12, yard 156, Jinghai 4th Road, Beijing Economic and Technological Development Zone, Daxing District, Beijing Patentee before: DONGFANG JINGYUAN ELECTRON Ltd. |