JPH11224278A - Mask pattern checking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To verify what kind of a mask pattern a final mask pattern uses and to prevent the generation of a mask pattern defect or the like by attaching version numbers to the mask patterns for respective function cells and extracting the respective version numbers of the mask patterns for constituting a semiconductor integrated circuit. SOLUTION: Whether or not a retrieved cell name is a cell defined in a latest version description file is judged (step S2). A cellversion number is extracted and obtained from the mask pattern of a cell to be checked (step S3). The latest version number of the cell to be checked is obtained from the latest version description file (step 34). The version number obtained from the mask pattern and the version number obtained from the latest version description file are compared (step S5). Thus, checking is performed by a simple method without performing layout comparison which requires a certain processing time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for verifying a mask pattern created in designing a layout pattern in the development of a large-scale integrated circuit (LSI).

[0002]

2. Description of the Related Art It takes several months or more from a circuit design to a final mask pattern to form a mask pattern for a semiconductor integrated circuit. During these periods, the designer takes out a mask pattern of a necessary cell from the library and uses it. However, after taking out the cell from the library, the mask pattern of the library may be changed. Changes to this library are usually
This is performed for the purpose of correcting an abnormality of a mask pattern, improving specifications, and improving yield.

If the designer does not know the change of the library, the final mask pattern does not match the mask pattern of the library, and as a result, a problem may occur in the mask pattern of the designed integrated circuit.

In some cases, a new integrated circuit is created by revising an integrated circuit whose design has been completed. In this case, even when a part of the previously used mask pattern is reused as it is, the library may be changed before the revision, and in this case, the same problem may occur.

On the other hand, a method of comparing mask patterns themselves is disclosed in Japanese Patent Application Laid-Open No. 6-326191. This publication discloses a technique for performing mask pattern comparison at high speed, but does not take any measures for responding to a change in a reference mask pattern for comparison.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the final mask pattern is determined so as not to cause a problem when the mask pattern of the library is changed after being taken out of the library at the time of design. An object of the present invention is to make it possible to verify whether a pattern is used and to prevent the occurrence of a mask pattern defect or the like. Another object of the present invention is to check whether the final library data has been used.

[0007]

A mask pattern chucking method according to the present invention is characterized in that a version number is assigned to a mask pattern for each functional cell and each version number of a mask pattern constituting a semiconductor integrated circuit is extracted. And

It is preferable that the extracted version number is compared with the latest version number of the corresponding function cell to check whether the mask pattern of the latest version cell is used.

According to the above configuration, it is possible to check whether or not the latest library data is used by a simple method without performing a layout comparison that requires a long processing time, so that a high-speed check can be performed.

Further, when there is a mismatch between the version numbers, it is preferable to display a problem and a reason for change in the old version.

With the above configuration, when the mask pattern of the old version is used, the problem and the reason for the change in the old version can be displayed. What kind of problem will occur? In addition, for that reason, it is possible to determine whether the mask pattern of the problematic cell should be replaced.

The mask pattern checking method of the present invention compares a mask pattern with a mask pattern of a library for each cell described in a cell type description file for determining whether a cell is a functional cell, and compiles the mask pattern. Decell is characterized in that the latest pattern is recombined and checked based on the parameters used.

According to the above configuration, the mask pattern of the entire mask pattern is not compared, and the check is performed for each function cell. However, the latest compiled cell that does not exist as mask pattern data in the library is used. It is possible to check whether it is done. This checking method requires more processing time than the above-described configuration in which the version numbers are compared. However, the management of the version information becomes unnecessary, and the mask patterns themselves are compared, so that the checking can be performed reliably.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a basic configuration of a mask pattern checking apparatus to which the present invention is applied.

As shown in FIG. 1, a processing device 1 includes a CPU
And a storage device in which a program for controlling these operations is stored, and performs a process of checking a mask pattern according to an operation flow described later. A command for checking is input to the processing device 1 from an input device 2 including a pointing device such as a keyboard and a mouse. Further, the processing apparatus 1 is provided with respective data from a storage device 3 storing mask pattern data and cell information as a description file, and checks the mask pattern. The result of this check is displayed on a display device 4 such as a CRT.

Next, the operation of the above processing apparatus will be described with reference to an operation flowchart. In the first embodiment, the storage device 3 is stored as a library in a state where bayonet numbers are added to respective necessary function cells. The functional cell includes a logic gate, a memory block, a multiplayer, and the like. As shown in FIG. 4, a version number is added to the mask pattern, and this version number is rewritten every time the library is revised. Then, as shown in FIG. 5, it is stored in the storage device 3 as the latest version description file. The version number of the library at the time of use for the mask pattern designed by the designer is stored as a description file together with the library of the mask pattern. When checking the mask pattern, a description file or the like of the mask pattern to be verified is stored in the storage device 3.

First, a first embodiment of the present invention will be described with reference to the flow chart showing the operation of FIG.

First, when the check operation is started, in step S1, the cell name used in the mask pattern is sequentially searched from the description file of the mask pattern to be checked stored in the storage device 3.

Subsequently, in step S2, it is determined whether the searched cell name is a cell defined in the latest version description file. If the cell is defined, the process proceeds to step S3 to check the version. If the cell is not defined, the process of step S8 is performed.

FIG. 5 shows a description example of the latest version description file. In this example, the format of the latest version description file is not limited, but the contents include the cell name of the function cell and its latest version. The determination in step S2 is that the cells used in the mask pattern include those that do not need to be checked for a version other than the functional cell. By removing this cell, extra checks are omitted, and processing is performed at high speed. To do it. An example of a cell that does not need to be checked is a lower-layer cell that constitutes a functional cell. However,
If these lower cells are included in the check,
Necessary items may be checked.

In step S3, the version number of the cell to be checked is extracted and obtained from the mask pattern of the cell, and the flow advances to step S4. FIG. 4 shows an example of a mask pattern in which a version number is described. In this example, the version of the mask pattern of the cell “CELL_A” is “3”.

In step S4, the latest version number of the cell to be checked is obtained from the latest version description file. In the example of FIG. 5, the version number “3” of “CELL_A” is obtained.

In step S5, the version number obtained from the mask pattern is compared with the version number obtained from the latest version description file. If they match, the process proceeds to step S8, and if they do not match, the process proceeds to step S6 to perform processing. In the example shown in FIG. 4 and FIG. 5, the version numbers of “CELL_A” are 3 and therefore match.

If the cells do not match, for example, the version number of “CELL_A” obtained from the mask pattern is 1
And "CEL" obtained from the latest version description file
If the version number of L_A "is 3, it is determined in step S5 that the version numbers do not match. In step S6, cell information in which the version numbers do not match is displayed. move on.
In this example, as shown in the first line of FIG.
The version of _A is 1, but the latest version is 3. Is displayed on the display device 4. Note that this display is an example and not a limitation. By comparing the version numbers in this way, it is possible to check whether the latest library data is used by a simple method without performing a layout comparison that requires a long processing time, and thus it is possible to check at high speed.

Subsequently, in step S7, a problem at the time of using the old version is displayed. The problem is the revision history from the old version to the latest version used in the mask pattern, and these are displayed for each version. In this way, by displaying the revision history, it is possible to know what kind of problem will occur if the old version is used as it is. In addition, for that reason, it is possible to determine whether the mask pattern of the problematic cell should be replaced.

In step S8, it is determined whether or not the processing from step S2 has been performed on all cells used in the mask pattern. If the processing has been completed for all cells, the processing is terminated. If there are remaining cells, the flow returns to step S2 to repeat the above operation.

Next, a second embodiment of the present invention will be described with reference to the flowchart of FIG. Tools for simply performing mask pattern comparison are available from many EDA vendors. In the second embodiment of the present invention, the mask pattern is compared with the latest version using these mask pattern comparison tools and the like. In the second embodiment, mask pattern comparison is performed for each functional cell.

When the check of the mask pattern is started,
First, in step S11, the cells described in the cell type description file are sequentially searched. FIG. 7 shows an example of the cell type description file. This file describes the parameters of the cells and the compiled cells prepared in the library. In this example, for the three cells described, “CELL_A”, “CELL_A”
"B" is a cell prepared in the library, and "CELL"
_C "is a RAM having 8 bits and 1024 words
Is a compiled cell.

Subsequently, in step S12, it is determined whether the cell obtained in step S11 is a cell used in the mask pattern defined in the latest version. If not, the process proceeds to step S18, and the process of step S18 is performed. In step S12, if applicable, the process proceeds to step S13, and it is determined in step S13 whether or not the cell is a compiled cell.

If it is determined in step S13 that the cell used for the mask pattern is not a compiled cell, the process proceeds directly to step S15.

If it is determined in step S13 that the cell is a compile cell, the process proceeds to step S14,
In step S14, a mask pattern of the latest version of the compiled cell is generated based on the parameters of the compiled cell. This is because a compiled cell does not exist in a completed form as a library, but is configured by combining subcells that constitute a compiled cell. In the example shown in FIG. 7, the number of bits is 8,
The mask pattern of the latest version of the RAM having 1024 words is generated.

In step S15, the latest mask pattern of the library and / or the compiled cell generated in step S14 is compared.
The comparison here is a graphical comparison. As a method of this comparison, a comparison process based on a tool or the like sold by an EDA vendor or a compressed bitmap disclosed in JP-A-6-326191 is used. Etc. can be used.

Subsequently, in step S16, step S
It is determined whether or not the mask patterns match based on the result of the comparison in 15;
Proceed to step S18, and if they do not match, step S18
Proceed to 17. In step S17, the information of the unmatched cell is displayed on the display device 4 as in the first embodiment described above.

As described above, the mask pattern of the entire mask pattern is not compared, and the check is performed in units of functional cells. However, the latest compiled cells that do not exist as mask pattern data in the library are used. Can be checked. This check method requires more processing time than the first embodiment, but has the advantage that the management of version information is not required, and that the check can be performed reliably because the mask pattern itself is compared. is there.

In step S18, for all the cells described in the cell type description file, step S18 is performed.
It is determined whether or not the processing after step 12 has been performed. If the processing has been completed for all the cells, the processing ends. If there are remaining cells, the flow returns to step S12 to perform the processing described above.

[0036]

As described above, in the mask pattern checking method according to the first and second aspects of the present invention, the latest library data is used by a simple method without performing a layout comparison that requires a long processing time. Can be checked at a high speed.

In the mask pattern checking method according to the third aspect of the present invention, when a mask pattern of an old version is used, a problem or a reason for change in the old version can be displayed. Therefore, it is possible to know what problem will occur if the old version is used as it is. Also, for that reason,
It is possible to determine whether the mask pattern of the problematic cell should be replaced.

In the mask pattern checking method according to a fourth aspect of the present invention, the mask pattern is not compared with the entire mask pattern but is checked in units of functional cells. Even for a compiled cell that does not exist, it is possible to check whether the latest one is used. In this checking method, processing time is longer than in the first and second aspects. However, it is not necessary to manage version information, and furthermore, since the mask pattern itself is compared, it can be surely checked. There are advantages.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a mask pattern check device to which the present invention is applied.

FIG. 2 is a flowchart showing a processing operation according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a processing operation according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing an example of a mask pattern in which a version number is described.

FIG. 5 is a schematic diagram illustrating a description example of a latest version description file.

FIG. 6 is a schematic diagram showing a display example of a problem in an old version.

FIG. 7 is a schematic diagram showing an example of a cell type description file.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing device 2 Input device 3 Storage device 4 Display device

Claims (4)

[Claims] 1. A mask pattern checking method comprising: attaching a version number to a mask pattern for each function cell; and extracting each version number of a mask pattern constituting a semiconductor integrated circuit. 2. The mask according to claim 1, wherein the extracted version number is compared with the latest version number of the corresponding function cell to check whether the latest version of the cell mask pattern is used. Pattern check method. 3. If there is a mismatch in the version numbers,
3. The method according to claim 2, wherein a problem and a reason for change in the previous version are displayed. 4. A mask pattern is compared with a mask pattern of a library for each cell described in a cell type description file for determining whether or not the cell is a functional cell, and a compiled cell is used to determine a parameter used. A mask pattern checking method characterized by re-synthesizing and checking the latest pattern.