阅读说明：本技术 一种结合图形匹配的opc修正方法 (OPC correction method combined with graph matching ) 是由 雷海波 乔彦辉 田明 王丹 于世瑞 于 2020-04-26 设计创作，主要内容包括：本发明提供一种结合图形匹配的OPC修正方法,提供图形库,对图形库中多个图形作常规OPC,得到第一掩膜层和第一目标层；根据第一掩膜层中每个分段与第一目标层中相应分段的距离差算出每个分段的偏移值,将该偏移值对应到图形的相应分段形成数据库；输入待执行OPC的版图,以该版图中的图形层为第二目标层,通过图形对第二目标层作图形匹配,再将得到匹配的图形根据数据库做分段和偏移,形成光罩前的迭代层；以第二目标层作目标层、以光罩前的迭代层作修正层执行基于模型的OPC修正,经迭代后得到目标轮廓的第二掩膜层。本发明能通过降低基于模型的OPC修正的迭代次数,提高修正效率,来降低OPC整体的运算时间。(The invention provides an OPC correction method combined with graph matching, which comprises the steps of providing a graph library, and carrying out conventional OPC on a plurality of graphs in the graph library to obtain a first mask layer and a first target layer; calculating an offset value of each segment according to the distance difference between each segment in the first mask layer and the corresponding segment in the first target layer, and corresponding the offset value to the corresponding segment of the graph to form a database; inputting a layout of OPC to be executed, taking a graph layer in the layout as a second target layer, performing graph matching on the second target layer through graphs, and segmenting and offsetting the matched graphs according to a database to form an iteration layer in front of a photomask; and performing model-based OPC (optical proximity correction) by taking the second target layer as a target layer and taking an iteration layer in front of the photomask as a correction layer, and iterating to obtain a second mask layer with a target outline. The invention can reduce the overall calculation time of OPC by reducing the iteration times of model-based OPC and improving the correction efficiency.)

1. An OPC correction method in combination with pattern matching, characterized in that the method comprises at least the steps of:

providing a graphic library, wherein the graphic library is a set consisting of a plurality of graphics with different shapes;

secondly, sequentially carrying out rule-based OPC correction and model-based OPC correction on the plurality of graphs in the graph library to sequentially obtain a first mask layer and a first target layer; then calculating an offset value of each segment according to the distance difference between each segment in the first mask layer and the corresponding segment in the first target layer, and corresponding the offset value to the corresponding segment of the graph to form a database;

inputting a layout of the OPC to be executed, and taking a graph layer in the layout as a second target layer;

performing pattern matching on the second target layer through the patterns in the pattern library, and segmenting and offsetting the matched patterns in the layout according to the database to form an iteration layer in front of the photomask;

and fifthly, performing model-based OPC (optical proximity correction) by taking the second target layer as a target layer and taking the iteration layer in front of the photomask as a correction layer, and obtaining a second mask layer with a target outline after iteration.

2. The OPC correction method in combination with pattern matching according to claim 1, wherein: the graphic library in the step one is formed by a method of drawing or intercepting a graphic.

3. The OPC correction method in combination with pattern matching according to claim 1, wherein: and updating the graphs in the graph library at any time according to needs in the step one.

4. The OPC correction method in combination with pattern matching according to claim 1, wherein: and the database in the second step comprises the graphs in the graph library, the offset value and the corresponding segments of the graphs corresponding to the offset value.

5. The OPC correction method in combination with pattern matching as claimed in claim 4, wherein: the database is updated as needed at any time.

6. The OPC correction method in combination with pattern matching according to claim 5, wherein: and the offset value in the second step is the distance between the first mask layer and the first target layer in the band direction.

7. The OPC correction method in combination with pattern matching according to claim 1, wherein: and the second target layer in the third step is a layer formed after regular OPC correction.

8. The OPC correction method in combination with pattern matching according to claim 1, wherein: and fifthly, inputting the layout, the second target layer and the iteration layer in front of the photomask into a model-based OPC system to execute the model-based OPC.

Technical Field

The invention relates to the technical field of semiconductors, in particular to an OPC (optical proximity correction) method combined with pattern matching.

Background

With the increasingly strict requirements on chip performance and energy consumption, in order to obtain a chip with a small area, high performance and low energy consumption, a semiconductor process experiences the development process of a non-OPC (optical proximity correction), rule-based OPC (rule-based OPC) correction method and model-based OPC correction method (model-based OPC), and the current general method is to firstly form a target layer (target layer) by using rule-based OPC as a layout according to factors such as photoetching and etching, and then obtain a final mask layer by performing the model-based OPC, wherein the time and the calculation resources spent on the model-based OPC correction are more and more. And as the CD (critical dimension) of layout design is reduced, the time spent by model-based OPC is greatly increased. Thus, pain points that reduce operating time are in the spotlight.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a method for performing OPC correction for matching patterns, which is used to solve the problem in the prior art that the time spent by model-based OPC correction is greatly increased as the critical dimension of the pattern in the layout is reduced.

To achieve the above and other related objects, the present invention provides a method for OPC correction in combination with pattern matching, the method at least comprising the following steps:

providing a graphic library, wherein the graphic library is a set consisting of a plurality of graphics with different shapes;

secondly, sequentially carrying out rule-based OPC correction and model-based OPC correction on the plurality of graphs in the graph library to sequentially obtain a first mask layer and a first target layer; then calculating an offset value of each segment according to the distance difference between each segment in the first mask layer and the corresponding segment in the first target layer, and corresponding the offset value to the corresponding segment of the graph to form a database;

inputting a layout of the OPC to be executed, and taking a graph layer in the layout as a second target layer;

performing pattern matching on the second target layer through the patterns in the pattern library, and segmenting and offsetting the matched patterns in the layout according to the database to form an iteration layer in front of the photomask;

and fifthly, performing model-based OPC (optical proximity correction) by taking the second target layer as a target layer and taking the iteration layer in front of the photomask as a correction layer, and obtaining a second mask layer with a target outline after iteration.

Preferably, the graphic library in the first step is formed by a method of drawing or cutting a graphic.

Preferably, the graphics in the graphics library in the step one are updated at any time as required.

Preferably, the database in step two includes the graphics in the graphics library, the offset value, and the corresponding segment of the graphics corresponding to the offset value.

Preferably, the database is updated as needed at any time.

Preferably, the offset value in the second step is a distance in a band direction between the first mask layer and the first target layer.

Preferably, the second target layer in step three is a layer formed after rule-based OPC correction.

Preferably, in the fifth step, the layout, the second target layer and the iteration layer before the photomask are input into a model-based OPC system to perform the model-based OPC correction.

As described above, the OPC correction method for closed pattern matching according to the present invention has the following advantageous effects: according to the invention, a database of the pre-offset is established, the pre-offset is applied to the layout through pattern matching, and the overall operation time of OPC can be reduced by reducing the iteration times of model-based OPC correction and improving the correction efficiency.

Drawings

FIG. 1 is a schematic flow chart of an OPC correction method in combination with pattern matching according to the present invention;

FIG. 2 is a flow chart of the OPC correction method combined with pattern matching according to the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1-2. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

The present invention provides an OPC correction method combined with pattern matching, as shown in fig. 1 and fig. 2, wherein fig. 1 shows a schematic flow chart of the OPC correction method combined with pattern matching of the present invention, and fig. 2 shows a block flow chart of the OPC correction method combined with pattern matching of the present invention, which includes the following steps in this embodiment:

providing a graphic library, wherein the graphic library is a set consisting of a plurality of graphics with different shapes; further, the graphic library in the first step is formed by a method for drawing or cutting a graphic. And further, the graphs in the graph library in the step one are updated at any time according to needs. That is, in the first step, the graphics are drawn or intercepted to form a graphics library. The graphic library is a collection of graphics with different shapes, and the library can be updated at any time as required.

Secondly, sequentially carrying out rule-based OPC correction and model-based OPC correction on the plurality of graphs in the graph library to sequentially obtain a first mask layer and a first target layer; then calculating an offset value of each segment according to the distance difference between each segment in the first mask layer and the corresponding segment in the first target layer, and corresponding the offset value to the corresponding segment of the graph to form a database; further, the database in step two includes the graph in the graph library, the offset value, and the corresponding segment of the graph corresponding to the offset value. Still further, the database is updated as needed at any time. Further, the offset value in the second step is a distance in a band direction between the first mask layer and the first target layer. That is, the step performs rule-based OPC (OPC correction) and model-based OPC (OPC correction based on a model) on the graphics in the graphics library, calculates an offset value (bias value) of each segment (fragment) according to a distance difference between the first mask layer and each segment (fragment) of the first target layer (target layer), and forms a database in which each bias value corresponds to the corresponding fragment of the graphics. That is, in the fourth step, a pattern matching (pattern match) is used and the database is called to give a pre-bias value to the second target layer, where the offset value is a moving amount of a segment (fragment) of each graph after model-based OPC is performed on the graphs in the graph library, that is, a distance in a band direction between the first mask layer and the first target layer.

Inputting a layout of the OPC to be executed, and taking a graph layer in the layout as a second target layer; further, the second target layer in step three is a layer formed after the rule-based OPC correction. In other embodiments, the second target layer may also be an original layout without rule-based OPC correction (rule-based OPC).

Performing pattern matching on the second target layer through the patterns in the pattern library, and segmenting and offsetting the matched patterns in the layout according to the database to form an iteration layer in front of the photomask; in other words, in the fourth step, pattern matching (pattern match) is performed on the second target layer (target layer) through the patterns in the pattern library, and then fragments and bias are performed on the matched patterns in the layout according to the database to form a mask before-photomask iteration layer.

And fifthly, performing model-based OPC correction by using the second target layer as a target layer and using an iteration layer (mask before layer) in front of the photomask as a correction layer, and obtaining a second mask layer with a target contour after iteration. Further, the layout, the second target layer and the iteration layer before the photomask are input into a model-based OPC system in step five to execute the model-based OPC correction. As shown in fig. 2, a basic implementation flow of the OPC correction method in combination with pattern matching according to the present invention is shown in fig. 2, wherein the finally formed mask layer is represented as the second mask layer according to the present invention. After the layout warns that the rule-based OPC is performed, the formed Target layer is represented as the second Target layer of the invention, and in other embodiments, the layout may not be subjected to the rule-based OPC correction, so that the Target layer in FIG. 2 is represented as the original layout.

Briefly, in the OPC correction method combined with the graph matching, a graph is firstly drawn or intercepted to form a graph library (the invention is a test mask for establishing a model), rule-based OPC and model-based OPC are carried out on the graph in the graph library, the offset value of each segment is calculated, a database is formed corresponding to the segment of the graph, and the database can be updated by adding a new graph;

after the layout needing OPC is subjected to rule-based OPC to generate a target layer, patterning the target layer by using the patterns in the pattern library, and segmenting and offsetting the matched patterns in the layout according to the database, namely, performing pre-bias before model-based OPC iterative computation to obtain a new layer mask _ before _ interaction;

inputting the layout, the second target layer, the mask _ before _ interaction and other layers into a model-based OPC, taking the second target layer as a target, taking the mask _ before _ interaction as a correction layer, and obtaining a second mask layer with a target contour after iteration. The method comprises the steps of establishing a graph library, performing model-based OPC on each graph in the graph library to obtain bias (deviant) of each segment (each edge can be divided into a plurality of line segments in the model-based OPC process), and then corresponding the bias values to each segment of each graph in the graph library to form a database of the pre-bias. When a layout needs to be subjected to model-based OPC, a similar graph is found out in the layout by using graph matching, a preset bias is directly given to the similar graph, and finally, the conventional model-based OPC is carried out. The invention can make the final simulation graph more easily conform to the expected target, and reduce the time spent by reducing the iteration number of model-based OPC.

In summary, the invention establishes a database of the pre-offset, applies the pre-offset to the layout through pattern matching, and can reduce the overall operation time of the OPC by reducing the iteration times of model-based OPC correction and improving the correction efficiency. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.