Não é gralha...

"Mask rights" (direitos aplicáveis a "mask works") são uma "criação "do "Semiconductor Chip Protection Act".

"Mask Works" are defined in the Act 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.

http://www.cerebalaw.com/chiptext.htm
http://www.baypatents.com/faq_display.asp?faq_id=34

Provavelmente o autor queria dizer "mask works".

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Note added at 19 hrs 59 mins (2005-01-20 16:27:52 GMT) Post-grading
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Eu já traduzi dezenas de contratos com texto quase igual a esse (ou seja, uma listagem padrão de direitos de propriedade intelectual), com a exceção de que se falava em \"maskwork rights\" ou \"mask work rights\" e a única dúvida que tive ao ver o contexto foi a ausência da palavra \"work\", o que imaginei que fosse a sua única dúvida também.

Da Wikipedia:
There are also more specialized varieties of so-called sui generis exclusive rights, such as circuit design rights (called mask work rights in USA law, protected under the Integrated Circuit Topography Act in Canadian law, and in European Community Law by Directive 87/54/EEC of 16 December 1986 on the legal protection of topographies of semiconductor products), plant breeder rights, plant variety rights, industrial design rights, supplementary protection certificates for pharmaceutical products and database rights (in European law).
http://en.wikipedia.org/wiki/Intellectual_property_rights

The United States Code defines a mask work as \"a series of related images, however fixed or encoded, 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 in which the relation of the images to one another is such that each image has the pattern of the surface of one form of the semiconductor chip product\" (17 USC § 901 (a) (2)). Mask work exclusive rights were first granted in the US by the Semiconductor Chip Protection Act of 1984. In Canada these rights are protected under the Integrated Circuit Topography Act (1990, c. 37). Equivalent legislation exists in Australia and Hong Kong.
http://en.wikipedia.org/wiki/Mask_work