United States
The United States Code (USC) 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 U.S.C. § 901(a)(2))]. Mask work exclusive rights were first granted in the US by the Semiconductor Chip Protection Act of 1984.
According to 17 U.S.C. § 904, rights in semiconductor mask works last 10 years. This contrasts with a term of 95 years for modern copyrighted works with a corporate authorship; alleged infringement of mask work rights are also not protected by a statutory fair use defense, nor by the typical backup copy exemptions that 17 U.S.C. § 117 provides for computer software. Nevertheless, as fair use in copyrighted works was originally recognized by the judiciary over a century before being codified in the Copyright Act of 1976, it is possible that the courts might likewise find a similar defense applies to mask work.
The non-obligatory symbol used in a mask work protection notice is Ⓜ (M enclosed in a circle; Unicode code point U+24C2
/U+1F1AD
or HTML numeric character entity Ⓜ
) or *M*.
The exclusive rights in a mask work are somewhat like those of copyright: the right to reproduce the mask work or (initially) distribute an IC made using the mask work. Like the first sale doctrine, a lawful owner of an authorized IC containing a mask work may freely import, distribute or use, but not reproduce the chip (or the mask). Mask work protection is characterized as a sui generis right, i.e., one created to protect specific rights where other (more general) laws were inadequate or inappropriate.
Note that the exclusive rights granted to mask work owners are more limited than those granted to copyright or patent holders. For instance, modification (derivative works) is not an exclusive right of mask work owners. Similarly, the exclusive right of a patentee to "use" an invention would not prohibit an independently created mask work of identical geometry. Furthermore, reproduction for reverse engineering of a mask work is specifically permitted by the law. As with copyright, mask work rights exist when they are created, regardless of registration, unlike patents, which only confer rights after application, examination and issuance.
Mask work rights have more in common with copyrights than with other exclusive rights such as patents or trademarks. On the other hand, they are used alongside copyright to protect a read-only memory (ROM) component that is encoded to contain computer software.
The publisher of software for a cartridge-based video game console may seek simultaneous protection of its property under several legal constructs:
- A trademark registration on the game's title and possibly other marks such as fanciful names of worlds and characters used in the game (e.g., PAC-MAN®);
- A copyright registration on the program as a literary work or on the audiovisual displays generated by the work; and
- A mask work registration on the ROM that contains the binary.
Ordinary copyright law applies to the underlying software (source, binary) and original characters and art.
But the expiration date for the term of additional exclusive rights in a work distributed in the form of a mask ROM would depend on an as yet[update] untested interpretation of the originality requirement of § 902(b):
(b) Protection under this chapter (i.e., as a mask work) 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 U.S.C. § 902, as of November 2010[update]).
Under one interpretation, a mask work containing a given game title is either entirely unoriginal, as mask ROM in general is likely a familiar design, or a minor variation of the mask work for any of the first titles released for the console in the region.