CN112987488B - OPC correction method - Google Patents
OPC correction method Download PDFInfo
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- CN112987488B CN112987488B CN202110196848.6A CN202110196848A CN112987488B CN 112987488 B CN112987488 B CN 112987488B CN 202110196848 A CN202110196848 A CN 202110196848A CN 112987488 B CN112987488 B CN 112987488B
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- 238000012937 correction Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 37
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000013461 design Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 238000012821 model calculation Methods 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 6
- 229920002120 photoresistant polymer Polymers 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 238000013459 approach Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 230000002925 chemical effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013041 optical simulation Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- 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
Abstract
The invention discloses an OPC correction method, which comprises the following steps: step one, establishing a plurality of OPC models with different accuracies; step two, providing a target layout needing OPC correction; selecting the OPC model with the lowest precision to perform multiple OPC operations on the target layout and forming a corresponding OPC intermediate layer; selecting an OPC model with higher precision to perform multiple OPC operations on an OPC intermediate layer formed by an OPC model with the precision of the previous layer and form a corresponding OPC intermediate layer; step five, repeating the step four until an OPC intermediate layer corresponding to the OPC model with the next highest precision is formed; and step six, selecting the OPC model with the highest precision, and performing multiple OPC operations on the OPC intermediate layer corresponding to the OPC model with the next highest precision to form a final OPC result. The invention can reduce the total OPC operation time under the condition of ensuring correction precision.
Description
Technical Field
The present invention relates to a method for manufacturing a semiconductor integrated circuit, and more particularly, to a method for correcting optical proximity effect (Optical Proximity Correction, OPC).
Background
In the photoetching process, a pattern structure corresponding to a layout on a Mask, namely a Mask (Mask), is projected into photoresist through an exposure system and forms a corresponding pattern structure in the photoresist, but due to optical reasons in the exposure process or chemical reactions of the photoresist, deviation exists between the pattern structure formed in the photoresist and the pattern structure on the Mask, the deviation needs to be modified in advance through OPC correction, and when the Mask subjected to OPC correction is adopted for exposure, the pattern structure formed in the photoresist is consistent with the designed pattern structure and meets the process production requirements.
OPC includes Rule-based OPC and model-based OPC.
Early rule-based OPC was widely used due to its simplicity and computational rapidity. However, this approach requires artificial formulation of OPC rules, which become extremely complex and difficult to continue as optical distortions become more pronounced.
Model-based OPC is now developed. The correction method based on the model OPC establishes an accurate calculation model through optical simulation, and then adjusts the edge of the graph to continuously simulate and iterate until the graph approaches to an ideal graph. Model-based OPC makes OPC procedures more complex and the demand for computing resources grows exponentially.
With the development of technical nodes, the smaller the pattern size is, the smaller the effect of the tiny physical effect on the lithography size is, the more complex parameters are modeled, such as introducing more complex physical effects of Mask3D and the like, and using more basis functions to fit the effect of the chemical effect of the photoresist on the pattern size, and the like, wherein the Mask3D is used for strictly modeling the electromagnetic wave scattered from the surface of the photomask, so as to represent the effect of the Mask surface three-dimensional structure on the diffraction of light.
FIG. 1 is a flow chart of a conventional OPC correction method; the existing OPC correction method comprises the following steps:
step one, establishing a high-precision OPC model. As technology nodes shrink, factors to be considered in the high-precision OPC model are more and more, and modeling parameters are more and more complex if the influence of a tiny physical effect is to be considered. The high-precision OPC model needs to be established strictly according to the mass production requirements.
Step two, providing a target layout needing OPC correction, wherein the graph of the target layout is in an initial state.
And thirdly, performing multiple OPC operations on the target layout by adopting a high-precision OPC model to form an OPC result and outputting the OPC result.
In the third step, because the parameters of the high-precision OPC model are complex, the OPC operation amount can be obviously increased when the OPC model obtains high precision, and the number of patterns in a unit area is multiplied along with the reduction of the size of the patterns, and the OPC operation time is almost multiplied, so that not only is the CPU operation resource amount, but also a serious challenge is provided for ensuring that the mask plate is published on time.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an OPC correction method, which can reduce the total OPC operation time under the condition of ensuring correction accuracy.
In order to solve the technical problems, the OPC correction method provided by the invention comprises the following steps:
step one, establishing a plurality of OPC models with different accuracies.
Step two, providing a target layout needing OPC correction, wherein the graph of the target layout is in an initial state.
And thirdly, selecting the OPC model with the lowest precision, performing multiple OPC operations on the target layout, and forming an OPC intermediate layer corresponding to the OPC model with the lowest precision.
And step four, selecting an OPC model with higher precision, performing multiple OPC operations on an OPC intermediate layer formed by an OPC model with the precision of the previous layer, and forming an OPC intermediate layer corresponding to the OPC model with the selected precision.
And step five, repeating the step four until an OPC intermediate layer corresponding to the OPC model with the next highest precision is formed.
And step six, selecting the OPC model with the highest precision, and performing multiple OPC operations on the OPC intermediate layer corresponding to the OPC model with the next highest precision to form a final OPC result.
The further improvement is that the first step comprises 2 precision OPC models, and the fourth step and the fifth step are omitted.
The OPC model with highest precision is an OPC model which is built according to the mass production requirement and meets the specification.
The OPC model with the next highest precision is an OPC model generated by simplifying model parameters or reducing model calculation range on the basis of the OPC model with the highest precision; the lower the accuracy, the faster the computation speed of the OPC model.
Further improvement is that the pattern period and the dimension are in the range of 1-2 times of the minimum design pattern period and the dimension, and the simulation trend of OPC operation is matched with the actual measurement data on the silicon substrate by adopting an OPC model with the accuracy lower than the next highest.
The further improvement is that the optimal solution of the OPC operation times corresponding to the OPC model with each precision in the third, fourth and fifth steps is that the final OPC result meeting the requirements is obtained and the saved total OPC operation time is the greatest.
In the sixth step, the number of times of OPC operations corresponding to the OPC model with the highest precision is 1 to 20, and the smaller the number of times of OPC operations corresponding to the OPC model with the highest precision is, the more the total OPC operation time is saved.
When the first step includes 2 OPC models with the precision, the OPC operation times corresponding to the OPC model with the lowest precision in the third step are 1 to 15 times, and the optimal solution of the OPC operation times corresponding to the OPC model with the lowest precision is selected from 1 to 15 times.
A further improvement is that the final OPC result obtained in step six meets the OPC precision requirements of mass production.
According to the invention, through setting a plurality of OPC models with different precision, the OPC operation can be performed by adopting the OPC model with lower precision in the initial stage, and the OPC operation can be performed by adopting the OPC model with highest precision in the final stage.
Meanwhile, in the initial stage, although the precision of the OPC model with lower precision is lower, the OPC model still accords with the correction direction and still accords with the convergence direction from the initial state of the target layout to the final state of the final OPC result, so that under the condition of ensuring that the correction direction is unchanged, the convergence can be quickened, the final OPC result can meet the precision requirement, and the precision of the final OPC result is still ensured by the OPC model with highest precision, so that the correction precision can be ensured.
Therefore, the invention can reduce the total OPC operation time under the condition of ensuring the correction precision.
Drawings
The invention is described in further detail below with reference to the attached drawings and detailed description:
FIG. 1 is a flow chart of a prior OPC correction method;
FIG. 2 is a diagram of an OPC correction method in accordance with an embodiment of the present invention;
FIG. 3A is a schematic diagram of an Edge Placement Error (EPE) after a first iterative OPC operation using the highest precision OPC model;
fig. 3B is a schematic diagram of edge placement errors after performing a second iterative OPC operation using the highest accuracy OPC model.
Detailed Description
FIG. 2 shows an OPC correction method in accordance with an embodiment of the present invention; the OPC correction method of the embodiment of the invention comprises the following steps:
step one, establishing a plurality of OPC models with different accuracies.
In the embodiment of the invention, the OPC model with highest precision is an OPC model which is built according to the mass production requirement and meets the specification.
The OPC model with the next highest precision is an OPC model generated by simplifying model parameters or reducing model calculation range on the basis of the OPC model with the highest precision; the lower the accuracy, the faster the computation speed of the OPC model.
The pattern period and the dimension are in the range of 1-2 times of the minimum design pattern period and the dimension, and the simulation trend of OPC operation is matched with the actual measurement data on the silicon substrate by adopting an OPC model with the accuracy lower than the next highest.
And step two, providing a target layout needing OPC (optical proximity correction) correction, wherein the graph of the target layout is in an initial state.
And thirdly, selecting the OPC model with the lowest precision, performing multiple OPC operations on the target layout, and forming an OPC intermediate layer corresponding to the OPC model with the lowest precision.
And step four, selecting an OPC model with higher precision, performing multiple OPC operations on an OPC intermediate layer formed by an OPC model with the precision of the previous layer, and forming an OPC intermediate layer corresponding to the OPC model with the selected precision.
And step five, repeating the step four until an OPC intermediate layer corresponding to the OPC model with the next highest precision is formed.
In the embodiment of the invention, the optimal solution of the OPC operation times corresponding to the OPC model with each precision in the third, fourth and fifth steps is that the saved total OPC operation time is the greatest while the final OPC result meeting the requirements is obtained.
And step six, selecting the OPC model with the highest precision, and performing multiple OPC operations on the OPC intermediate layer corresponding to the OPC model with the next highest precision to form a final OPC result. The final OPC results meet the OPC accuracy requirements of mass production.
In a preferred embodiment, step one includes 2 precision OPC models, and step four and step five are omitted. At this time, the number of OPC operations corresponding to the OPC model with the lowest precision in the third step is 1 to 15, and the optimal solution of the number of OPC operations corresponding to the OPC model with the lowest precision is selected from 1 to 15.
In the sixth step, the number of times of OPC operation corresponding to the OPC model with the highest precision is 1 to 20, and the smaller the number of times of OPC operation corresponding to the OPC model with the highest precision is, the more total OPC operation time is saved.
The effect of the method of the embodiment of the invention on the overall OPC operation time saving will now be described with reference to specific parameters:
the conventional method shown in fig. 1 uses a high-precision OPC model to perform 8 OPC operations to obtain an OPC result that meets the requirements.
When the method provided by the embodiment of the invention adopts two OPC models, the OPC operation times of the OPC model with the lowest precision in the third step, namely the OPC operation times of the low-precision OPC model are 5 times, and the OPC operation times of the OPC model with the highest precision in the sixth step are 5 times. And step six, the OPC model with the highest precision is equal to the high-precision OPC model adopted by the existing method in precision.
The operation speed relationship between the low-precision OPC model and the high-precision OPC model is as follows:
the simulation operation of the high-precision OPC model is carried out once for about 38 minutes;
the simulation operation of the low-precision OPC model is carried out once for about 8 minutes;
the total OPC operation time of the existing OPC correction method is 8×38=304 minutes;
the total OPC calculation time of the method of the embodiment of the present invention is 5×8+5×38=230 minutes;
it can be seen that, although the total iteration number of the method of the embodiment of the present invention may be greater than or equal to the existing OPC correction method, the calculation speed of the low-precision OPC model may save about 24.4% of OPC calculation time compared with the conventional method.
According to the method, through setting of a plurality of OPC models with different precision, OPC operation can be performed by adopting the OPC model with lower precision in the initial stage, and OPC operation is performed by adopting the OPC model with highest precision in the final stage.
Meanwhile, in the initial stage, although the precision of the OPC model with lower precision is lower, the correction direction is still consistent, namely the convergence direction from the initial state of the target layout to the final state of the final OPC result is still consistent, so that the final OPC result is not influenced while the convergence is quickened under the condition that the correction direction is unchanged, the precision of the final OPC result is still ensured by the OPC model with highest precision, and the correction precision can be ensured by the method provided by the embodiment of the invention. FIG. 3A is a schematic diagram of edge placement errors after performing a first iterative OPC operation using the OPC model with the highest accuracy; FIG. 3A shows a target layer graph 101 of a plurality of layouts, edges of the graph 101 are corrected after OPC operation is performed for the first iteration, and an OPC result simulation layer graph after the edge correction is shown as a mark 102 a; as shown in fig. 3B, an edge placement error diagram after performing the OPC operation of the second iteration by using the OPC model with the highest accuracy is shown, and the OPC result simulation layer diagram after the edge correction is shown as a reference numeral 102B. It can be seen that in the initial correction phase, as shown in fig. 3A and 3B, the difference between the patterns 102a and 102B and the target layer pattern 101 is large, and reference is specifically made to the values in the dashed circles 103A and 103B, the dashed circles 104a and 104B, and the dashed circles 105a and 105B, respectively. It can be seen that, in the initial stage of OPC operation using the OPC model, after the pattern correction of the Mask, there is a large difference between the OPC correction result and the final convergence result, the pattern movement amount of the Mask for each iteration of the loop is related to the edge placement error, when the edge placement error is large, the movement amount of the Mask pattern is often close to the set single maximum movement upper limit value, only the Mask correction movement direction is required to be correct at this time, and the final correction result is not significantly affected by the accuracy of the movement amount, so that the quick approximate simulation operation can be performed using the low-accuracy OPC model, and the simulation operation is not required to be performed using the more time-consuming high-accuracy OPC model. When the correction result approaches the target after several iterative operations are performed, the fineness of the movement amount is more important, and a high-precision OPC model is needed to realize finer correction, so that the OPC result which meets the requirements similar to the existing OPC correction mode can be finally obtained.
Therefore, the method of the embodiment of the invention can reduce the total OPC operation time under the condition of ensuring the correction precision.
The present invention has been described in detail by way of specific examples, but these should not be construed as limiting the invention. Many variations and modifications may be made by one skilled in the art without departing from the principles of the invention, which is also considered to be within the scope of the invention.
Claims (9)
1. An OPC correction method, characterized by comprising the steps of:
step one, establishing a plurality of OPC models with different accuracies;
step two, providing a target layout needing OPC correction, wherein the graph of the target layout is in an initial state;
selecting the OPC model with the lowest precision, performing multiple OPC operations on the target layout, and forming an OPC intermediate layer corresponding to the OPC model with the lowest precision;
selecting an OPC model with higher precision to perform multiple OPC operations on an OPC intermediate layer formed by an OPC model with the precision of the previous layer and forming an OPC intermediate layer corresponding to the OPC model with the selected precision;
step five, repeating the step four until an OPC intermediate layer corresponding to the OPC model with the next highest precision is formed;
and step six, selecting the OPC model with the highest precision, and performing multiple OPC operations on the OPC intermediate layer corresponding to the OPC model with the next highest precision to form a final OPC result.
2. The OPC correction method of claim 1 wherein: the first step comprises 2 precision OPC models, and the fourth step and the fifth step are omitted.
3. The OPC correction method as claimed in claim 1 or 2, characterized in that: the OPC model with the highest precision is an OPC model which is built according to the mass production requirement and meets the specification.
4. The OPC correction method of claim 3 wherein: the OPC model with the next highest precision is an OPC model generated by simplifying model parameters or reducing model calculation range on the basis of the OPC model with the highest precision; the lower the accuracy, the faster the computation speed of the OPC model.
5. The OPC correction method of claim 4 wherein: the pattern period and the dimension are in the range of 1-2 times of the minimum design pattern period and the dimension, and the simulation trend of OPC operation is matched with the actual measurement data on the silicon substrate by adopting an OPC model with the accuracy lower than the next highest.
6. The OPC correction method as claimed in claim 1 or 2, characterized in that: and step three, the optimal solution of the OPC operation times corresponding to the OPC model with each precision in the step four and the step five is that the total OPC operation time is saved the most while the final OPC result meeting the requirements is obtained.
7. The OPC correction method of claim 6 wherein: in the sixth step, the number of times of OPC operation corresponding to the OPC model with the highest precision is 1 to 20, and the smaller the number of times of OPC operation corresponding to the OPC model with the highest precision is, the more total OPC operation time is saved.
8. The OPC correction method of claim 6 wherein: when the first step includes 2 OPC models with the precision, the OPC operation times corresponding to the OPC model with the lowest precision in the third step are 1 to 15 times, and the optimal solution of the OPC operation times corresponding to the OPC model with the lowest precision is selected from 1 to 15 times.
9. The OPC correction method of claim 1 wherein: and step six, the final OPC result meets the OPC precision requirement of mass production.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004302263A (en) * | 2003-03-31 | 2004-10-28 | Sharp Corp | Method for correcting mask pattern and photomask |
| CN103246153A (en) * | 2013-04-28 | 2013-08-14 | 上海华力微电子有限公司 | Territory map layer design method of semiconductor chip and mask plate thereof |
| CN103631085A (en) * | 2012-08-29 | 2014-03-12 | 中芯国际集成电路制造(上海)有限公司 | Correction method for optical proximity correction model |
| CN109459911A (en) * | 2018-12-25 | 2019-03-12 | 上海微阱电子科技有限公司 | A method of improving OPC model precision |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7512927B2 (en) * | 2006-11-02 | 2009-03-31 | International Business Machines Corporation | Printability verification by progressive modeling accuracy |
| JP5913979B2 (en) * | 2008-06-03 | 2016-05-11 | エーエスエムエル ネザーランズ ビー．ブイ． | Model-based process simulation method |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004302263A (en) * | 2003-03-31 | 2004-10-28 | Sharp Corp | Method for correcting mask pattern and photomask |
| CN103631085A (en) * | 2012-08-29 | 2014-03-12 | 中芯国际集成电路制造(上海)有限公司 | Correction method for optical proximity correction model |
| CN103246153A (en) * | 2013-04-28 | 2013-08-14 | 上海华力微电子有限公司 | Territory map layer design method of semiconductor chip and mask plate thereof |
| CN109459911A (en) * | 2018-12-25 | 2019-03-12 | 上海微阱电子科技有限公司 | A method of improving OPC model precision |
Non-Patent Citations (1)
| Title |
|---|
| 蔡懿慈等.优化的基于模型的光学邻近矫正算法.半导体学报.2005,26(第03期),第180-184页. * |
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