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Layout Signature, Tool and Data Independent Algorithms to Verify that an IP's Physical Designs Have Not Changed for Layers Specified.

IP.com Disclosure Number: IPCOM000172768D
Publication Date: 2008-Jul-14
Document File: 2 page(s) / 36K

Publishing Venue

The IP.com Prior Art Database

Abstract

The layout signature is a checksum which can be used to determine if the layout of a hard IP block has been modified. The proposed algorithm can be used in any design tool and will provide the same checksum values. The layout signature is saved in VSIA Signature text tag allowing users of the IP to check for undocumented design changes.

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Layout Signature, Tool and Data Independent Algorithms to Verify that an IP's Physical Designs Have Not Changed for Layers Specified.

   

The layout signature is a checksum which can be used to determine if the layout of a hard IP block has been modified. The proposed algorithm can be used in any design tool and will provide the same checksum values. The layout signature is saved in VSIA Signature text tag allowing users of the IP to check for undocumented design changes.

The layout signature provides a method for checking that a physical design has not change when it is transferred from different teams or changed to a different output format. The signatures would be calculated by the selected algorithm and written into the design as text following the VSIA text tagging standard. Only layers used for mask production would be used. Properties like text would be ignored. The design then can be checked at a later point to see if it has been modified for layers used in mask production. The physical layout signature would be the same for any design tool environment (GDSII, Cadence, Oasis, Open Access, etc). The signature will check for merged shapes. A shape made up of multiple rectangles would be merged to form a single polygon with points only on the vertices. In addition paths would be flattened into polygons. This is done as part of the algorithm flow and does not change the actual design database, other than the optional writing of the signature back into the design as text. The signature is not an absolute checksum for layout cha...