A gridless multilayer channel router

A technique for routing gridless channels is presented. This technique can handle channels of two or more layers without restricting layers to vertical or horizontal direction. Also, it considers all the important routing metrics simultaneously. Since this technique is based on the design rules, it is also capable of handling grid-based channels. The algorithm has been implemented in C on Sequent Balance 8000, which uses the UNIX operating system. The algorithm was run on several examples of gridless and grid-based channels with two or more layers, and for all of them it achieved good results. Besides its capability of routing both types of channels, having no restriction on the direction of each layer was important in achieving a more efficient solution for a channel. On both layout designs, this feature helped minimize the channel with the wire length, and the number of contacts