JPH027542A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the mandays of layout modifying work by a method wherein a plurality of logic elements which are not used in the circuit drawings but are to be used for the circuit modification are arranged in raws where logic elements of the integrated circuit automatically designed according to the circuit drawings are arranged, with the gate terminals of the logic elements for circuit modification connected to the power supply line. CONSTITUTION:Logic elements 2 are layout, automatically arranged and wired on the basis of connection information of circuit drawings, for example, an invertor, two-input NANDs, two-input NORs and the like are arranged as arbitrary circuit modifying logic elements 3 without the connecting information which is used in an automatic layout and its gate contact 4 is fixed on a power source. The contact 4 connects a gate so as to fix the gate signal of the circuit modifying logic elements 3 on the power source.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor integrated circuit capable of automatic layout.

[Conventional technology]

In general, automatic layout of semiconductor integrated circuits is performed based on the connection information of the logically designed circuit diagram. Since functional blocks are automatically placed and wired, it may not be possible to satisfy one type of placement position and wiring length necessary to realize the circuit function. If this semiconductor integrated circuit is formed by diffusion and evaluated, it will not be able to achieve sufficient functionality due to the heavy load on the signal lines, and the layout will need to be modified. This layout modification will have to start from the first step.

[Problem to be solved by the invention]

The conventional automatic layout of semiconductor integrated circuits described above determines the placement positions and wiring lengths required to fully satisfy the functions that the semiconductor integrated circuit should achieve.

Since it is not possible to specify the type arbitrarily, if the signal line is placed and routed using automatic layout, and a signal line is overloaded and malfunctions, it is necessary to start correcting the layout from the beginning. However, one drawback is that it requires a huge amount of cost and man-hours.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor integrated circuit which eliminates such drawbacks and allows subsequent circuit modifications and layout modifications by providing more additional circuits than the originally designed circuit.

[Means to solve the problem]

In the configuration of the semiconductor integrated circuit of the present invention, a plurality of logic elements for circuit modification not used in the circuit diagram are placed in each column in which the logic elements of the integrated circuit automatically laid out according to the circuit diagram are arranged, and their gate terminals are connected to the power supply. It is characterized by being connected to the line.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a layout diagram of a semiconductor integrated circuit illustrating an embodiment of the present invention. In this layout, 1 is a power supply line, 2 is various logic elements, 3 is a logic element for circuit modification that is not used in the original design, and 4 is a gate that fixes the gate signal of logic element 3 for circuit modification to the power supply. This is the contact that connects the

In this way, in this embodiment, the logic element 2 is in a layout that is automatically placed and wired based on the connection information of the circuit diagram, and in each column of this layout, there is an arbitrary layout in which the connection information used in the automatic layout does not exist. As the logic element 3 for changing the circuit, for example, an inverter, a two-man NAND, a two-man NO
R, etc. are arranged, and the gate contact 4 is fixed to a power source.

〔Effect of the invention〕

As explained above, the present invention enables diffusion, evaluation, and placement of automatically laid out semiconductor integrated circuits by incorporating logic elements that are not required in the first logic circuit layout into the layout from the beginning. Even if the function cannot be fully satisfied due to heavy load on the signal line due to a wiring defect, the function can be changed by changing only the wiring and contact process using logic elements for circuit modification built in each column, making it possible to change the layout. It is extremely effective in reducing man-hours, costs, and delivery times.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a semiconductor integrated circuit illustrating an embodiment of the present invention. 1...Power supply line, 2...Arbitrary logic element, 3...
・Logic element for circuit modification, 4...Gate input contact.

Claims (1)

[Claims] A plurality of logic elements for circuit modification not used in the circuit diagram are arranged in each column in which logic elements of an integrated circuit automatically laid out according to the circuit diagram are arranged, with their gate terminals connected to a power supply line. Semiconductor integrated circuit.