CN105842977B

CN105842977B - Method for post-optical proximity correction repair

Info

Publication number: CN105842977B
Application number: CN201510018670.0A
Authority: CN
Inventors: 杜杳隽
Original assignee: Semiconductor Manufacturing International Shanghai Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp
Priority date: 2015-01-14
Filing date: 2015-01-14
Publication date: 2020-03-10
Anticipated expiration: 2035-01-14
Also published as: CN105842977A

Abstract

The invention provides a method for post-optical proximity correction repair. The method comprises the following steps: the first step is as follows: forming a local correction region based on error marks generated by an optical proximity correction process prior to the post-optical proximity correction repair; and a second step: local optical proximity correction is performed within the local correction area until no further false marks are produced. The method for repairing the post-optical proximity correction provided by the invention is used for performing the post-optical proximity correction based on the local correction area, so that the calculation amount can be greatly reduced, and the efficiency is improved.

Description

Method for post-optical proximity correction repair

Technical Field

The invention relates to the technical field of semiconductors, in particular to a method for post-optical Proximity Correction (post-OPC) repair.

Background

As integrated circuits become more complex, feature sizes become smaller and smaller. When the feature size of an integrated circuit approaches the system limit of exposure of a lithography machine, i.e., the feature size is close to or smaller than the lithography light source, the layout fabricated on the silicon wafer can exhibit significant distortion, a phenomenon known as optical proximity effect. In order to cope with the optical proximity effect, a resolution enhancement technique is proposed. Among them, optical proximity correction (i.e., OPC) has become the most important technique.

OPC is not a process that can obtain accurate results once, but is a continuously iterative process that requires multiple verification modifications. post-OPC repair (i.e. the repair after verification of the layout on which the OPC has been performed) then becomes a necessary step for improving the OPC quality. The existing post-OPC repair method is based on the whole layout, such as the area of the whole chip, to redo OPC, and the method is time-consuming, large in computation amount and low in efficiency.

Disclosure of Invention

In view of the deficiencies of the prior art, the present invention provides a method for post-optical proximity correction repair. The method comprises the following steps: the first step is as follows: forming a local correction region based on an error mark (error mark) generated by an optical proximity correction process prior to the post-optical proximity correction repair; and a second step: local optical proximity correction is performed within the local correction area until no further false marks are produced.

In one embodiment of the invention, the method further comprises performing a global optical proximity correction based on the whole chip after the second step.

In one embodiment of the present invention, the method further comprises performing a global optical proximity correction interspersed with the intermediate stages performed in the second step.

In one embodiment of the invention, the second step is carried out in the intermediate stages of: the local optical proximity correction has been performed a predetermined threshold number of times.

In one embodiment of the invention, the predetermined threshold is 10.

In one embodiment of the invention, the method is directed to optical proximity correction of a via layer.

In one embodiment of the present invention, the connection hole is a contact hole (CT).

In one embodiment of the invention, the local optical proximity correction comprises an edge shift of the contact hole pattern.

In one embodiment of the invention, the edge is moved by a distance of 0.5 nm.

In one embodiment of the invention, the size of the local modification area is 0.9 micrometer x 0.9 micrometer.

The method for repairing the post-optical proximity correction provided by the invention is used for performing the post-optical proximity correction based on the local correction area, so that the calculation amount can be greatly reduced, and the efficiency is improved.

Drawings

The following drawings of the invention are included to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIG. 1 illustrates an example of optical proximity correction to a contact hole;

FIG. 2 shows a flow diagram of a method for post-optical proximity correction repair, in accordance with one embodiment of the present invention;

FIG. 3 illustrates an example of post-optical proximity correction repair of the contact hole of FIG. 1 using the method of FIG. 2; and

FIG. 4 shows a flow diagram of a method for post-optical proximity correction repair, according to another embodiment of the present invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to provide a thorough understanding of the present invention, detailed steps and detailed structures will be set forth in the following description in order to explain the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.

OPC has become an indispensable approach for Critical Dimension (CD) control and yield enhancement in integrated circuit manufacturing processes. The process deviation is pre-compensated by modifying the design pattern to improve the image restoration capability and resolution. However, in the current phase, the OPC verification process is performed on the entire chip, which requires many iterations of the process, which is very time consuming. For example, OPC for a communication hole such as a contact hole or a via hole.

FIG. 1 illustrates an example of optical proximity correction to a contact hole. The OPC correction procedure for the contact holes is designed to ensure that the profile of the pattern on the wafer can match the contact hole target. However, even a well-prepared and adjusted rework procedure (rebuilpe) may still deviate some contours from the target. As shown in fig. 1, the contact hole profile after optical proximity correction is too close to the Gate (GT) for a distance less than the 10 nm specification, which may adversely affect the electrical properties of the circuit. The box B in fig. 1 marks the problem edge that needs to be moved inwards. To perform the problem edge movement, post-optical proximity correction repair is required. As mentioned above, the conventional post-optical proximity correction repair process is performed on the entire chip, requiring many iterative repairs to clear all errors, and consumes a lot of CPU time.

FIG. 2 shows a flow diagram of a method 200 for post-optical proximity correction repair, in accordance with one embodiment of the present invention. As shown in fig. 2, the method 200 includes the steps of:

step 201: the local correction region is formed based on error marks generated by an optical proximity correction process prior to post-optical proximity correction repair.

Step 202: the local optical proximity correction is performed within the local correction area formed in step 201 until no more false marks are generated.

An error mark will be obtained by the OPC verification of the previous process. A locally corrected region may be generated based on the initial error flag. The locally modified region encompasses the initial error mark. Following the example of FIG. 1, FIG. 3 illustrates an example of post-optical proximity correction repair of the contact hole of FIG. 1 using the method of FIG. 2. As shown in fig. 3, a local correction area, which may be denoted as REOPC, is generated based on the original error mark (block B of fig. 1), which is only a very small area of the entire chip, as shown in fig. 3. For example, the size of the region is, for example, 0.9 micrometers x 0.9 micrometers. The local correction area REOPC may be regarded as a filter of the entire chip. All subsequent repairs and verifications will be performed within this local correction area, REOPC. The local optical proximity correction may include an edge shift of the contact hole pattern. Alternatively, the magnitude of the edge movement may be set to 0.5 nm.

In particular, the verification of the first cycle within the local correction area may generate a new number of error marks that is much smaller than the number of error marks generated in the previous cycle (i.e., the optical proximity correction process prior to post-optical proximity correction repair). And the error mark generated by the verification of the first loop in the local correction area is transmitted to the next loop to be continuously repaired and verified. Thus, the error flag gets smaller and smaller with the number of cycles until it is completely cleared. Thus, the CPU time can be greatly reduced. It has been found through experiments that for some large-sized chips (e.g. 10 mm x 10 mm chips), the repair with the existing method takes two weeks, whereas the method according to the present invention can be completed in only two days.

It will be appreciated by those of ordinary skill in the art that the post-optical proximity correction repair of contact holes illustrated in FIG. 3 is merely an example, and that the method for post-optical proximity correction repair according to embodiments of the present invention may also be applied to any other application requiring post-OPC repair.

FIG. 4 shows a flow diagram of a method 400 for post-optical proximity correction repair, in accordance with another embodiment of the present invention. As shown in fig. 4, the method 400 includes the steps of:

step 401: the local correction region is formed based on error marks generated by an optical proximity correction process prior to post-optical proximity correction repair.

Step 402: local optical proximity correction is performed within the local correction zone formed in step 401 until no more false marks are produced.

Step 403: global optical proximity correction based on the entire chip is performed after step 402.

Step 401 and step 402 are similar to step 201 and step 202 of method 200, respectively, and therefore are not described herein again.

In the method 400, when step 403 is added after step 402, a global optical proximity correction is performed in step 403. This ensures that the entire chip has no remaining error flags.

Preferably, the global optical proximity correction is also performed once interspersed in the intermediate stage performed in step 402, so as to make the repairing effect better. In particular, the intermediate stage performed by step 402 may be, for example, the number of times the local optical proximity correction has been performed by a predetermined threshold. The predetermined threshold may be, for example, 10 times. That is, after the local optical proximity correction based on the local correction region has been performed 10 times in step 402, the global optical proximity correction based on the entire chip may be performed once, the local optical proximity correction in step 402 may be performed later, and 10 times may be performed.

Therefore, the whole post-optical proximity correction repair is mainly based on local optical proximity correction, and global optical proximity correction is respectively carried out in the intermediate stage and the final stage of the local optical proximity correction, so that the repair efficiency is improved, and the better repair quality is ensured.

The present invention has been illustrated by the above embodiments, but it should be understood that the above embodiments are for illustrative and descriptive purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications may be made in accordance with the teachings of the present invention, which variations and modifications are within the scope of the present invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A method for post-optical proximity correction repair, the method comprising:

the first step is as follows: forming a local correction region based on error marks generated by an optical proximity correction process prior to the post-optical proximity correction repair; and

the second step is as follows: performing a local optical proximity correction within the local correction zone until no further false marks are produced;

the method further comprises performing a global optical proximity correction based on the entire chip after the second step.

2. The method of claim 1, further comprising interspersing the intermediate stages performed in the second step with a global optical proximity correction.

3. The method according to claim 2, characterized in that the second step is carried out in the intermediate phases: the local optical proximity correction has been performed a predetermined threshold number of times.

4. The method of claim 3, wherein the predetermined threshold is 10.

5. The method of any one of claims 1-4, wherein the method is for optical proximity correction of a connected aperture layer.

6. The method of claim 5, wherein the connection hole is a contact hole.

7. The method of claim 6, wherein the local optical proximity correction comprises edge shifting of a contact hole pattern.

8. The method of claim 7, wherein the edge is moved a distance of 0.5 nanometers.

9. The method of claim 6, wherein the size of the local modification area is 0.9 microns x 0.9 microns.