Anil,

In the '80's there was much controversy patent vs. copyright in both software and chip fabrication. It was finally settled in 1984. Prior to that time firms filed and claimed for chip masks while pursuing legal and political avenues to achieve final adjudication of this controversy.

The act in 1984 defines mask art as "a series of related images, however fixed or encoded (1) having or representing the predetermined three-dimensional pattern of metallic, insulating, or semiconductor material present or removed from the layers of a semiconductor chip product; and (2) in which series the relation of the images to one another is that each image has the pattern of the surface of one form of the semiconductor chip product."

Of interest, the copyright protection granted for the mask does not extend to the architecture it implements.

regards,
p