JPS636855A - Analysis method for integrated-circuit mask pattern - Google Patents

Abstract

PURPOSE:To quickly determine a resulting value near to the true value by means of a computer for analysis of mask patterns, by reducing the patterns in an integrated circuit to determine resistances and their values. CONSTITUTION:A minimal width W4 is first extracted from a pattern 1. The pattern is then reduced to a half width of W4. A pattern W5 small in width next to W4 is then extracted. A patterning part (a, b, c, d) having a width is reduced to a half width of W5. Such operations of extraction and reduction are repeated until all the smallest widths of the patterns become zero. As regards computing resistances in the parts becoming zero in their pattern widths, the first part becoming zero, that is, the d-e part of the reduced pattern 4 is made to have a resistance expressed in Rde (fs, W4, lde). The resistances are determined in the same way. A resistance path from the contact parts 2 to 3 can be formed by connecting the determined resistances R2f, Rfg, Rgd, and Rde.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of analyzing an integrated circuit mask pattern, and more particularly to a method of analyzing an integrated circuit mask pattern using a computer.

[Conventional technology]

゛ Conventionally, electrical analysis of integrated circuit mask patterns has been mainly performed manually. Therefore, there was a problem in that it required a large amount of man-hours, and there were also many calculation errors, making it difficult to obtain good analysis results. Therefore, CAD (Computer Ai)
ded Design) is progressing. Currently CA
The method used in the D method is the rectangular division method.0For example, to explain the calculation of the resistance value and resistance path of a wiring pattern, the mask pattern is divided into rectangles and the center line of each rectangle is used as the resistance path. This is the way to proceed.

FIG. 5 is a pattern diagram for explaining how to find a resistance path using the conventional rectangular division method. .

Divide pattern 1 into rectangles as shown by the broken lines in the figure, and
Let the midpoint of each I line be i. Contact part 2
A resistance path 7 is obtained by connecting a line segment from the center point, i, to the contact portion 3. The length of each line segment is e 2b, 1! hl+1! Expressed as +3,
Letting the resistance be represented by R2,,Rh,,R,,, the overall length is +23, and the resistance is represented by R23, L23= 1!2b+ (! b++ 113R23
= R211+ R111+ R13.

[Problem that the invention seeks to solve]

In the conventional CAD method described above, the mask pattern is simply divided into rectangles and the line connecting the midpoints of each rectangle side is used as a resistance path, so there are problems with processing time and the calculated value may be too large compared to the true value. For this reason, there is a problem that it has not been put into practical use and still relies on manual labor.

SUMMARY OF THE INVENTION An object of the present invention is to provide an integrated circuit mask pattern analysis method that uses a computer to obtain calculated values close to the true values.

[Means for solving problems]

The integrated circuit mask pattern analysis method of the present invention includes the first step of extracting and reducing the minimum width pattern among the wiring patterns of the integrated circuit mask, and the step of extracting the minimum width pattern among the reduced patterns. a second step in which the reduction is repeated for all patterns until the reduction is completed; a third step in which a resistance value is calculated for each reduced pattern; and a fourth step of calculating a resistance value between the two points using the calculated resistance value.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are diagrams showing an integrated circuit mask pattern and a reduced pattern for explaining an embodiment of the present invention.

As shown in FIG. 1 (A), the mask pattern 1 is assumed to be L-shaped, each portion having a width of W1 to W4, and having contact portions 2.3.

Extraction, reduction, and calculation of the wiring resistance and wiring path between the contact portions 2 and 3 will be explained.

First, extract the minimum width in pattern 1.

In FIG. 1 (A>), W4 corresponds to it.

Next, the pattern is reduced to a width of 1/2 of this W4. The reduced patterns are shown as a to e in FIG. 1 (13).

Next, a pattern with the next smallest width after W4 is extracted. 1st
In the diagram (C), Ws corresponds to this yield. Then, the wide pattern portions (a, b, c, d) are reduced to a width of 1/2 of Ws. The reduced patterns are indicated by f and g. This kind of extraction and reduction work is performed when the minimum width of all patterns is all 0.
Repeat until.

Next, a method for calculating the resistance at a portion where the pattern width becomes 0 will be explained.

FIG. 2 is an equivalent resistance diagram of the reduced pattern of FIG. 1(C), and FIG. 3 is an equivalent resistance diagram of FIG. 1 (A>).

First, the resistance between de and e of the reduced pattern 4, which is the part where the width of the pattern becomes O in the first time, is set as Rde. Ra
e is a function of resistance per unit area fs, width W4, d, and length e de. Therefore, Rd, (f s ,
W4, j'd-).

Next, let R□ be the portion where the pattern width becomes O in the second reduction, that is, the resistance between f and g of the reduced pattern 5. R
e, is similar to Rde, fs, W,.

Since it is a function of e□ (et- is the length of the line molecule g), R
It can be expressed as □(fs, Ws, e□).

Next, find a resistance path from contact part to contact part. Search from the contact part 2 side to find the closest resistance. In this case, the closest one is vertex f. Let R2f be the resistance between the contact portion 2 and the apex f. The resistance during this period is located in the second reduction area, so the width is changed to Wl
shall be. Therefore, resistor R25 is fs, Wl, l! 2f(
e2f is a function of the length between the contact portion 2 and the apex.

Therefore, R2r (f s , WI, !! □r)
It is expressed as

Next, the resistor Rde passing through the resistor Rf8 and located at the closest distance from the vertex g is searched. If the length between vertices g and d is e gd, the resistance Rgd between g and d is f5.
It is a function of Wl, e□. Therefore, Rfd(f s ,
Wt, e gct).

As described above, the resistances Ft2t, R□, and R□.

By connecting Ra, a resistance path from contact portion 2 to contact portion 3 is completed. If the resistance value of the resistance path obtained in this way is R23, and the resistance path length is L23, then R23=R23(R2t, Rr,, R□, Rdl)
l) L23= L23 (12r, l rg, l!
gd, e ds).

Figure 4 shows the resistance path and resistance value thus determined.

FIG. 6 is a block diagram of the main parts of a computer used in an embodiment of the present invention.

The input device 8 is, for example, a magnetic tape device, and inputs data necessary for analysis of the present invention. The arithmetic unit 9 performs arithmetic processing to obtain the aforementioned resistance path and resistance value. The storage device 10 is, for example, a magnetic disk, and supports arithmetic processing. The output device 11 is, for example, a plotter, and prints desired data. The output can also be displayed on a cathode ray tube. These are connected by a bus 12.

〔Effect of the invention〕

As explained above, the present invention employs a method of determining the resistance path and resistance value while reducing the integrated circuit pattern, so a computer is used to analyze the mask pattern, and the result is close to the true value. This has the advantage that it can be quickly requested.

[Brief explanation of the drawing]

1(A) to 1(C) are diagrams showing an integrated circuit mass pattern and a reduced pattern for explaining one embodiment of the present invention, and FIG. 2 is a diagram showing the pattern of FIG. 1(C). 3 is an equivalent resistance diagram of the reduced pattern of FIG. 1(A), FIG. 4 is a diagram showing the resistance path and resistance value of the mask pattern obtained by the present invention, and FIG. 5 is a diagram of the conventional one. FIG. 6 is a pattern diagram for explaining how to find a resistance path using the rectangular division method. FIG. 6 is a block diagram of the main parts of a computer used to implement the present invention. 1... Pattern, 2.3... Contact part, 4, 5
...Reduced pattern, 6,7...Resistance path, 8.
... input device, 9 ... calculation section, 10 ... storage device,
11... Output device, 12... Bus, W1 to W6...
・Pattern width. +1. i Not 1f 2nd figure 1?1d (h, Wt, 21!+ Kaya J side

Claims (1)

[Claims] The first step of extracting and reducing the minimum width pattern among the wiring patterns of the integrated circuit mask, and the extraction and reduction of the minimum width pattern among the reduced patterns are repeated for all patterns until the reduction is completed. The second step and
A third step of calculating a resistance value for each reduced pattern, forming a resistance path between two points for which resistance is to be determined by connecting the reduced patterns, and using the calculated resistance value to connect the two points. a fourth step of calculating a resistance value of an integrated circuit mask pattern.