JP2857439B2 - Wiring capacity calculator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a wiring capacitance calculating device that calculates a wiring capacitance of each wiring when designing a wiring pattern of a semiconductor integrated circuit, and relates to a calculated wiring capacitance in a design stage and an actual wiring capacitance in an integrated circuit. An object of the present invention is to provide a wiring capacitance calculating device that does not cause an error between the wiring capacitance and an input device for inputting position coordinate data of a wiring layer and a wiring, and that the wiring does not overlap with another wiring layer. A unit wiring capacitance storage device in which a unit wiring capacitance when formed and a unit wiring capacitance when wiring is overlapped with another wiring layer are stored in advance, and data from the input device and the wiring capacitance storage device Based on the data from, the wiring is divided into a part that does not overlap with another wiring layer and a part that overlaps with another wiring layer, and the wiring capacitance of the part that does not overlap with the other wiring layer and the wiring Other distribution And a wiring capacitance calculating device for calculating a wiring capacitance of a portion overlapping the line layer and calculating a total sum.

[Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring capacitance calculating device that calculates a wiring capacitance of each wiring when designing a wiring pattern of a semiconductor integrated circuit.

2. Description of the Related Art In recent years, a semiconductor integrated circuit has adopted a multi-layer wiring structure based on its high integration, or has been designed in a state in which the distance between wirings is becoming increasingly closer. In such a semiconductor integrated circuit, the wiring capacitance generated between the wirings has a great effect on its operation. Therefore, the wiring pattern is designed after calculating in advance whether the wiring capacitance between the wirings satisfies a predetermined value. Have been.

[Conventional technology]

A conventional procedure for calculating a wiring capacitance of an integrated circuit pattern as shown in FIG. 5 by a wiring capacitance calculating device will be described. In FIG. First and second wirings 2 and 3 which are bent in a rectangular shape (the vertical direction is defined as the X direction and the horizontal direction is defined as the Y direction in the drawing) are connected to each other. Three wirings 4 are provided. Each such wiring
2, 3, and 4 wiring portions in the X direction and the wiring portion in the Y direction are formed in separate wiring layers in the vertical direction, and are connected to each other by contact holes 10. Further, as shown by hatching in the figure, a power supply wiring layer 5 for supplying power to the memory unit 1 is formed in substantially the same area as the memory unit 1 above the memory unit 1.

When the XY coordinate data of each of the wirings 2, 3, and 4 is input from the input device of the calculating device, the wiring capacity of each of the wirings 2, 3, and 4 is calculated by the calculating device. The wiring capacitance is calculated based on the wiring lengths in the direction and the Y direction. That is, for example, in the first wiring 2, the unit wiring capacitance per unit length of the wiring part in the X direction and the unit wiring capacitance per unit length of the wiring part in the Y direction are multiplied by the product of the wiring lengths in the X and Y directions. The wiring capacitance is calculated. For example, the wiring capacitance of the third wiring 4 is calculated by the product of the unit wiring capacitance of the wiring in the Y direction and the wiring length.

[Problems to be solved by the invention]

Although the calculation procedure of the wiring capacitance by the above-described calculating device does not consider the increase of the unit wiring capacitance at the position overlapping the power supply wiring layer 5 in the first and second wirings 2 and 3,
Since the area of the power supply wiring layer 5 was small and the wiring length overlapping the power supply wiring layer was relatively short, there was no large error between the calculated wiring capacitance of each of the wirings 2 and 3 and the actual wiring capacitance.

However, due to the recent demand for faster memory units 1,
As shown in FIG. 6, when the power supply wiring layer 5 is expanded in a wide range in the upper layer of the memory section 1, a portion where the unit wiring capacity becomes large in each of the wirings 2, 3, and 4 overlaps with the power supply wiring layer 5. Due to the increase, a large error occurs between the calculated wiring capacitance and the actual wiring capacitance, which hinders the normal operation of the integrated circuit.

An object of the present invention is to provide a wiring capacitance calculating apparatus which does not cause an error between a calculated wiring capacitance at a design stage and a wiring capacitance on an actual integrated circuit.

[Means for solving the problem]

FIG. 1 is a diagram illustrating the principle of the present invention. That is, the wiring capacitance calculation device includes the input device 7, the unit wiring capacitance storage device 8, and the wiring capacitance calculation device 6. The input device 7 is for inputting position coordinate data of the wiring layer and the wiring.
The unit wiring capacitance storage device 8 previously stores a unit wiring capacitance when a wiring is formed without overlapping with another wiring layer and a unit wiring capacitance when the wiring is formed with overlapping another wiring layer. Things. The wiring capacitance calculating device 6 divides the wiring into a portion not overlapping with another wiring layer and a portion overlapping with another wiring layer based on the data from the input device 7 and the data from the wiring capacitance storage device 8. At the same time, the sum of the wiring capacitance of a portion not overlapping with another wiring layer of the wiring and the wiring capacitance of a portion overlapping with another wiring layer of the wiring is calculated.

[Action]

When the wiring is formed so as to overlap with another wiring layer area, the wiring is divided into a part overlapping with the other wiring layer area and a part not overlapping with each other, and each divided part is stored in the storage unit 8 in advance. The wiring capacitance is calculated based on the wiring capacitance, and the wiring capacitance of each divided portion is summed up to calculate the wiring capacitance of the wiring.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
Description will be made with reference to the drawings. Note that the same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

Referring to FIG. 2, an input device 7 is connected to a computer 6, and various wiring layers or a large number of wiring layers are connected to the computer 6 via the input device 7 in FIG. Position data on the XY coordinates of the wiring is input. The library 8 connected to the computer 6 stores a large number of unit wiring capacities per unit length of wiring that is provided so as to overlap the power supply wiring layer or another wiring layer. Further, a memory 9 similarly connected to the computer 6 temporarily stores a calculation result by the computer 6.

Next, a case where the wiring capacity of the wiring pattern created by the automatic wiring processing apparatus is calculated by the wiring capacity calculating apparatus having the above configuration will be described with reference to FIGS. 3 and 4. FIG.
When the wiring pattern as shown in FIG. 4 is formed by the automatic wiring processing device and the wiring pattern is inputted from the input device 7, the computer 6 stores the wiring pattern in the memory 9 (STEP1, hereinafter referred to as S ), The unit wiring capacity of each wiring 2, 3, 4 from the library 8, ie, each wiring
2, 3, and 4 unit wiring capacitances in the X and Y directions, and each wiring 2,
The unit wiring capacity when 3 and 4 overlap with the power supply wiring layer 5 is read and stored in the memory 9 (S2).

Next, the computer 6 connects the power supply wiring layer 5 to each of the wirings 2, 3,.
As shown in FIG. 3, each wiring 2,
Coordinate data D1 to D4 of intersections between 3, 4 and the boundary of power supply wiring layer 5
Is calculated (S3). Then, each of the wirings 2, 3, and 4 is divided by the coordinate data D1 to D4, the wiring capacity of each divided part is calculated based on the wiring length and the unit wiring capacity, and the wiring capacitance of each divided part is calculated. To calculate the wiring capacitance of each of the wirings 2, 3, and 4 (S4).

As described above, in this wiring capacitance calculating apparatus, each of the wirings 2, 3, and
In the portion where 4 overlaps the power supply wiring layer 5 and in the portion where it does not overlap, the wiring capacitance is calculated based on the unit wiring capacitance stored in advance, so that the calculated values of the wiring capacitances of the wirings 2, 3, and 4 are actually calculated. Each wiring 2,3,4 in manufactured integrated circuit
The occurrence of an error with the wiring capacitance can be prevented. Therefore, it is possible to prevent an operation failure of the integrated circuit due to an error between the calculated wiring capacitance of each of the wirings 2, 3, and 4 and the actual wiring capacitance.

〔The invention's effect〕

As described above in detail, the present invention provides an excellent wiring capacitance calculating apparatus that does not cause an error between the calculated wiring capacitance at the design stage and the actual wiring capacitance on an integrated circuit. It is effective.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a block diagram illustrating a wiring capacitance calculating apparatus according to one embodiment of the present invention, FIG. 3 is an explanatory diagram illustrating a wiring capacitance calculating procedure according to one embodiment, FIG. 5 is a flowchart showing the operation of one embodiment, and FIGS. 5 and 6 are explanatory diagrams showing a calculation procedure by a conventional wiring capacitance calculation device. In the figure, 6 is a wiring capacity calculation device (computer), 7 is an input device, and 8 is a unit wiring capacity storage device (library).

Continuation of the front page (56) References JP-A-1-128543 (JP, A) JP-A-3-196548 (JP, A) JP-A-2-287885 (JP, A) JP-A-63-69289 (JP) JP-A-64-32385 (JP, A) JP-A-61-144040 (JP, A) JP-A-3-194659 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB (Name) H01L 21/82 G06F 17/50

Claims (1)

(57) [Claims] An input device for inputting position coordinate data of a wiring layer and a wiring; a unit wiring capacitance and a wiring when the wiring is formed so as not to overlap with another wiring layer; A unit wiring capacitance storage device (8) storing beforehand a unit wiring capacitance when formed, and data based on data from the input device (7) and data from the unit wiring capacitance storage device (8). The wiring is divided into a portion not overlapping with another wiring layer and a portion overlapping with another wiring layer, and a wiring capacitance of a portion not overlapping with another wiring layer of the wiring and a portion overlapping with another wiring layer of the wiring And a wiring capacitance calculating device for calculating the sum of the wiring capacitances.