JPH10172876A - Method for compressing eb data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ease constraints of design by performing a compressing method focusing attention on level structure (block) with which compression efficiency is higher. SOLUTION: A compressing method is composed of the following processes: 1) to specify a block to be compressed; 2) to detect the state of the black to be compressed placed on a chip and patterns entered into the block; 3) to take 'OR' of entered patterns in each position of the object to be compressed; and 4) to make 'SUB' of the entered patterns obtained at the process 3) from the block graphics. Graphics which are not overlapping outside entered patterns are automatically extracted. The above functions can be realized by a program for forming and processing EB data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an EB data compression method.

[0002]

2. Description of the Related Art In the production of an LSI chip, logic design → circuit design → layout pattern design and design are performed, and the completed pattern is used as a mask pattern and transferred onto a silicon substrate to form an actual LSI. The EB data is used to convert the completed pattern into a mask pattern.
This is data for inputting a B drawing device. (Refer to FIG. 1.) Since EB data represents a fine LSI pattern as a set of rectangles that can be drawn by an EB drawing apparatus, the EB data has a general large capacity, and requires a large amount of graphic operations to create it. Therefore, a large amount of computer processing time is required.

[0003] In particular, the tendency is large-scale memory LSI.
(DRAM) and the like. In order to reduce this, a pattern having the same shape is cut out, and one cutout pattern and its arrangement position are output as EB data, thereby reducing the data amount and the creation time. Things are going on. This is called data compression. (Refer to FIG. 2) As the conventional method, there are the following two methods.

(1) A method of compressing data paying attention to the hierarchical structure of data, and a method of compressing data by designating a block (hereinafter referred to as a block) of the same pattern arranged at a plurality of locations in a layout design.

(2) A method in which attention is paid to individual graphic patterns, and when the same pattern is used repeatedly, this is used as a compression unit and compressed.

Comparing the methods (1) and (2), in the method (1), since the data is compressed by focusing on the layout hierarchy, it is easy to specify the compression unit. As a large area pattern can be collectively compressed, high compression efficiency is an advantage.

On the other hand, as a drawback, when there is a pattern connected to the block to be compressed (usually because it is an electronic circuit), it cannot be compressed because the pattern of that part differs depending on the location (see FIG. 3). Therefore, it is necessary to limit the area to be compressed to a part of the block, and to restrict the area at the design stage so that an external pattern does not enter the block.

On the other hand, in the case of (2), since the same pattern is automatically recognized, there are few restrictions at the design stage, but the same pattern requires a large amount of calculation for automatic recognition. The quantity increases. Therefore, a large area cannot be compressed in practice. Also, automatic weaving is difficult when it overlaps with another pattern, and in reality, it can only be handled when the pattern is independent. (Refer to FIG. 4.) As a result, the compression ratio is lower than the method (1).

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to relieve design constraints while performing a compression method focusing on a hierarchical structure (block) having high compression efficiency.

[0010]

In order to achieve the above object, (1) a block is designated as a compression target. (External designation) (2) The state where the block to be compressed is arranged on the chip,
Detect the pattern invading the block.

(3) The intrusion pattern at each position of the compression target is ORed.

(4) The intrusion pattern obtained in (3) is "SUB" from the block figure.

→ Automatic extraction of figures that do not overlap with external intrusion patterns The above functions are realized. (See FIG. 4) At the design stage of the compression block, the pattern can be designed without considering the range of the intrusion pattern and the like.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Designate a block as a compression target. (External designation) (2) The state where the block to be compressed is arranged on the chip,
The pattern invading the block is detected, and the intrusion pattern at each position of the compression target is ORed.

(3) "SUB" is performed on the intrusion pattern obtained in (2) from the figure of the block.

→ Automatic extraction of figures that do not overlap with external intrusion patterns The above functions are realized by a program for EB data creation processing.

[0017]

According to the present invention, it is possible to process a complicated intrusion pattern from the outside, thereby facilitating pattern design when using compression and realizing a high pattern compression ratio.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an EB data creation process.

FIG. 2 is an explanatory diagram of an example of a compression process.

FIG. 3 is an explanatory diagram of compression in consideration of a hierarchy.

FIG. 4 is an explanatory diagram of compression in consideration of a pattern.

FIG. 5 is an explanatory diagram of a compression method according to the present invention.

Claims (1)

[Claims] An EB data used for drawing a mask pattern of an LSI chip by EB is compressed in accordance with a hierarchical structure at the time of pattern layout design, thereby reducing a working time of the EB data and an EB data amount. EB to do
Data compression method.