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Mask work

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.

Mask work rights under US Law

According to 17 USC § 904 (, semiconductor mask work monopolies last only ten years (in contrast to effectively perpetual terms for copyrighted works) and are not subject to any fair use rights including the typical backup exemptions that 17 USC § 117 provides for computer software. Nevertheless, as fair use in true copyright was originally recognized by the judiciary before being codified in statute1, it may one day be recognized in mask work protection as well.

The correct symbol used in a mask work's copyright notice is Ⓜ (M enclosed in a circle; Ⓜ) or *M*, not (M) in parentheses as your web browser may render it.

Mask works, copyrights, and read-only memory

Mask work copyright is technically not a copyright at all (except in compound phrases like "Copyright Office", the word copyright does not even appear in 17 USC chapter 9) but a sui generis right. The exclusive rights granted to mask work owners are more limited than those granted to copyright holders (for instance, modification is not an exclusive right of mask work owners). However, the same Title grants both mask work rights and copyrights, and mask work rights share more in common with copyrights than with other forms of intellectual property such as patents or trademarks, so many analyses lump them with copyright, especially when they are used alongside copyright to protect a read-only memory (ROM) part that contains computer software.

The publisher of software for a cartridge-based video game console normally is granted three distinct monopolies: a trademark on the game's title and possibly other marks such as names of worlds and characters used in the game a Form TX copyright on the program (registered by sending in source code) or a Form PA copyright on the visual displays generated by the work (depending on whether code or art dominates a program), and a Form MW "copyright" on the ROM that contains the binary. The lack of an exception analogous to the § 117 backup exception for copyrights means that Nintendo can go after sites that carry ROM dumps copyright 1992 or later, but ROM sites hosting mostly software for older consoles may fall under normal copyright law's fair use, library (17 USC § 108), and backup exemptions. Of course, if you have developed your own software for a console and have released it under a free software license, this doesn't apply.

However, there does exist an interpretation of the originality requirement of § 902(b) that may set the effective date for the expiry of mask work date based on the release of the console, not the particular cartridge.

(b) Protection under this chapter shall not be available for a mask work that -
(1) is not original; or
(2) consists of designs that are staple, commonplace, or familiar in the semiconductor industry, or variations of such designs, combined in a way that, considered as a whole, is not original
(17 USC 902,, as of February 2003).
Under this interpretation, a mask work containing a given game title is a minor variation of the mask work for the first title released for the console in the region, normally the cartridge included with the system. In the United States, this is Super Mario Brothers (NES), Tetris (Game Boy), Altered Beast (Sega Genesis), Super Mario World (Super NES), Mario's Tennis (Virtual Boy), Super Mario 64 (Nintendo 64), or Super Mario Advance (Game Boy Advance). (This has not been tested in court to the knowledge of Wikipedia's editors.)

This could explain why Nintendo waited until lawmakers passed the DMCA and foreign counterparts before releasing a game console that used media other than cartridges.

Please note: Wikipedia does not give legal advice

1: In the specific case of backups as fair use, see House Report No. 94-1476 on § 117