Semiconductor integrated circuit, method of designing semiconductor integrated circuit, and device for designing the same
AssigneeNEC Electronics Corporation
InventorHiroshi Kishibe
Life of this patent
Estimating the term…
Abstract
Placement is performed by using a library created by enlarging cell frames of at least one type of cells out of a plurality of types of standard cells constituted by using transistors having different characteristics for the respective types of cell. More preferably, the overlap between cells is judged by using unenlarged cell frames as adjacent boundaries for standard cells of the same type, and the overlap between cells is judged by using enlarged cell frames as adjacent boundaries for standard cells of different types. This enables automatic placement in which different types of cells are mixed.
Claims12
A method of designing a semiconductor integrated circuit having a plurality of types of cells constituted by using transistors having different characteristics for the respective types of cell, the method comprising the steps of:
- creating at least one type of cell out of the plurality of types of cells, as a cell having a first cell boundary, which indicates a cell frame defined including polygon patterns of transistors, wirings between the transistors and terminals, and a second cell boundary obtained by enlarging the first cell boundary in four directions;
- and
- placing the cells so that outermost cell boundaries of different types of cells do not overlap one another.
A device for designing a semiconductor integrated circuit having a plurality of types of cells constituted by using transistors having different characteristics for the respective types of cell, the device comprising,
- a cell library in which the plurality of types of cells are stored while having cell attributes distinguished from one another and having first cell boundaries indicating cell frames corresponding to the cell attributes and second cell boundaries obtained by enlarging the first cell boundaries in four directions, and
- placement means having functions:
- inputting a netlist and constraint information to execute placement of the cells using cell data stored in the library;
- eliminating an overlap of the first cell boundaries, if there are cells which have the same cell attributes and of which first cell boundaries overlap, by moving at-least one of the relevant cells;
- and eliminating an overlap of the second cell boundaries, if there are cells which have different cell attributes and of which second cell boundaries overlap, by moving at least one of the relevant cells.
A semiconductor integrated circuit comprising:
- at least one first cell each including at least one first transistor;
- and
- at least one second cell each including at least one second transistor;
- wherein the first transistor and the second transistor have characteristics different from each other;
- wherein the first cell and the second cell are apart from each other keeping a distance equal to or larger than a predetermined distance;
- and
- wherein the first cell and the second cell are arranged in a mixed manner.
Dependencies are inferred from the claim text.