Method for optimizing component placement in designing a semiconductor device by using a cost value

Abstract

An initial placement is performed based on a net list and a cell library. An optimum effective temperature Tc is derived based on a cost value obtained if the positions of two components, selected from a list of exchange candidates (where all the components are registered), are exchanged with each other and a cost value before the exchange is performed. A first component and a second component, adjacent to the first component, are selected from the list of exchange candidates and the positions thereof are exchanged with each other. And at the optimum effective temperature Tc, it is determined in accordance with a Monte-Carlo method using the cost values before and after the exchange whether or not the exchange is allowable. If it is allowable, the placement after the exchange is decided as a new placement. Otherwise, the placement before the exchange is decided as a new placement. Subsequently, new placements are decided N times for each component included in the list of exchange candidates, and candidate components, the exchange number M of which is equal to or larger than a predetermined number Nm (where Nm<N), are registered to draw up a new list of exchange candidates. And the respective processing steps from deriving the optimum effective temperature Tc to registering the candidate components are repeatedly performed by using the new list of exchange candidates.