Method and apparatus for automating routing in the presence of frozen mask layers
Publication Date: 2010-Mar-29
The IP.com Prior Art Database
Disclosed is an automated method by which certain interconnect layers can be frozen and others modified when using an automated wiring tool, so as to minimize rewiring to as few mask layers as possible. The key contributions of the method (and its embodiment) are the freezing of routes to prevent removal of shapes (and optional unfreezing upon completion), in combination with the selection of routable layers (and valid vias) to prevent addition of shapes, on those layers the user does not wish to modify. Furthermore, this method accounts for the complexity of additional Design For Manufacturing (DFM) data (non-routing shapes) that may be included in the mask data that must not be changed, so as to avoid design rule violations or electrical shorts (or opens).