JPH05299510A - Cad device for routing design - Google Patents

Abstract

PURPOSE:To narrower channel width by decreasing the degree of wiring congestion by correcting the position of global routing based on the information sent from a routing information means. CONSTITUTION:Routing information is inputted in step S1, and the allotment of feedthrough and the decision of in-channel route are conducted in step S2. The degree of wiring congestion in a channel region is computed by step S3, and the feedthrough routing between cells is corrected by step S4. A channel routing is conducted in step S5, and placement and routing information is outputted in step S6. Then, feedthrough is linearly arranged by global routing in the region where a feedthrough can be done, and each route is determined in all channels. The degree of congestion when the route is bent is computed, and the feedthrough position is shifted when the degree of congestion is decreased. The degree of congestion in the channel region is decreased by routing the feedthrough between cells in a bent form, and the area of the whole chips can be reduced by narrowing the channel width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring design CAD device used for wiring design of a standard cell type LSI.

[0002]

2. Description of the Related Art An example of wiring of a conventional standard cell type LSI is shown in FIG. The wiring is divided into a channel wiring performed in a channel area other than the cell row area and a feedthrough wiring passing on the cell row. There are two types of feed-through wirings, an on-cell feed-through and an inter-cell feed-through, which are wired in a straight line.

[0003]

Conventionally, the feedthrough was wired only in a straight line, but by providing complicated wiring in the feedthrough as well, the degree of wiring congestion in the channel region can be reduced and the channel width can be reduced. Since it can be made small, the purpose is to reduce the area of the entire chip.

[0004]

A CAD device for wiring design according to the present invention for achieving the above object comprises a standard cell and wiring means for inputting layout information of the standard cell and performing general wiring. Wiring information means for obtaining wiring information in the wiring area between the standard cells, and to correct the position of the general wiring based on the information from this wiring information means and the position information of the standard cell and the corrected wiring The position information is output.

[0005]

According to the present invention, the feedthrough is not limited to a straight line but can be bent and wired by the above structure.
It is possible to change the degree of wiring congestion in the channel region. At this time, the channel width can be reduced by adopting a wiring pattern that reduces the degree of wiring congestion.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a flow chart of wiring processing, FIG. 2 is a flow chart of inter-cell feedthrough wiring correction processing, and FIG. 3 is a specific application example. In the CAD device for wiring design of the present embodiment, first,
Wiring information is input in step S1 and rough wiring (feedthrough allocation and in-channel wiring route determination) is performed based on this information (step S2). In step S3, the wiring congestion degree in the channel region is calculated, and the on-cell feedthrough wiring is corrected based on the calculation result (step S4). Then, in step S5, channel wiring is performed, and placement and routing information is output (step S6). Figure 1
The rough wiring of FIG. 1 allocates feedthroughs in straight lines, and determines the route of each wiring in all channels. Thereby, the wiring congestion degree in the channel can be calculated.

Next, the procedure for correcting the on-cell feedthrough wiring will be described with reference to FIG. Step S11
In step S12, one on-cell feedthrough is selected, and the right and left feedthrough enable areas are obtained (step S12). In step S13, movable positions at the upper and lower ends of the feedthrough on the cell are obtained, and in step S14, the wiring congestion degree of the upper or lower channel when the feedthrough endpoint is moved to the movable position is obtained. Then, in step S15, it is determined whether or not there is a position where the wiring congestion degree decreases, and if there is a position where the wiring congestion degree decreases, the process proceeds to step S16, and wiring is performed within the feasible area so that the feedthrough end point can be moved to that position. Bending, the value of the wiring congestion degree is updated in step S17, and the process proceeds to the next process. Further, if it is determined in step S15 that there is no position where the wiring congestion degree decreases, the processes of steps S16 and S17 are omitted and the process proceeds to the next process. The above process is repeated a specified number of times and then the next process is performed.

FIG. 3A is an example showing the degree of wiring congestion in the feedthrough and the channel region which are assigned by the rough wiring. At this time, the feed-through possible area is shown in FIG.
In the case of (B), one is on the left side of the top of the cell frame, and two are on the right side.
There is one feed-through movable position on the left side and one on the right side of the lower side of the cell frame. In the case of the example of FIG. 3, if the feedthrough position at the upper end is moved to the right by two, the wiring congestion degree of the upper channel is reduced. Therefore, as shown in FIG. To move the feedthrough position. As a result, in the upper channel, the wiring congestion degree at the feed-through position and the position on the left side thereof is reduced from 2 to 1, so that the channel width is reduced by 1 track in FIG.

[0009]

As described above, according to the present invention, the on-cell feedthrough is bent and wired to reduce the wiring congestion degree in the channel region and to reduce the channel width. The area of can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart of a wiring process that is an embodiment of the present invention.

FIG. 2 is a flowchart of an on-cell feedthrough wiring correction process.

FIG. 3 is a diagram showing a specific application example.

FIG. 4 is a diagram showing a wiring example of a conventional standard cell type LSI.

Claims (1)

[Claims] 1. A standard cell, wiring means for inputting layout information of the standard cell to perform rough wiring, and wiring information means for obtaining wiring information in a wiring area between the standard cells,
A CAD device for wiring design, which corrects the position of the rough wiring based on the information from the wiring information means and outputs the position information of the standard cell and the corrected position information of the wiring.