Integrated Circuit Layout Design Protection Series: Part 3September 7, 2023

Title 17 of the U.S. Code concerns copyright laws. Chapter 9 of Title 17 is entirely dedicated to the protection of Mask Works. 17 U.S.C. § 901 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.” As mentioned in Part 2 of this Series, Mask work exclusive rights were first granted in the US by the Semiconductor Chip Protection Act of 1984, and the U.S. was able to convince many other countries around the world to offer similar protections as the result of a conference held in Washington D.C. in 1989.

According to 17 U.S.C. § 904, exclusive rights in semiconductor mask works last 10 years. While this tracks the term set forth in the TRIPS agreement that adopts part of the IPIC Treaty, it is important to note this is a stark contrast from the usual 95 year term for modern copyrighted works of art having corporate authorship. Beneficially to holders of the 10 year exclusive rights, alleged infringement of mask work rights appear (though this is not settled) not to be protected by any statutory fair use defense, nor by typical backup copy exemptions provided under 17 U.S.C. § 117 (which relates to computer software).

Mask works are highly unique in that they also utilize the symbol Ⓜ to identify mask work protection. As you can see, the M is enclosed in a circle, much like how the C in the copyright symbol (©) is enclosed. The Unicode code point for this symbol is U+24C2/U+1F1AD and the HTML numeric character entity is Ⓜ or *M*.

The right to reproduce the mask work or (initially) distribute an IC made using the mask work is exclusive to the owner of the IP. Similar to 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: a right specifically created to protect rights where other (more general) laws were inadequate or inappropriate. The reasons for the inadequacy of existing patent and copyright laws were discussed in Part 1 of this Series.

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 patentee’s rights to exclude others from using its invention would not prohibit an independently created mask work of identical geometry. Furthermore, reproduction for reverse engineering of a mask work is specifically permitted under Chapter 9 of Title 17. 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.

As an example, the publisher of software for a cartridge-based video game console may seek simultaneous protection of its property under several legal constructs. The publisher may choose to register the code of the software as a copyright, in addition to registering as a copyright the audiovisual displays generated by the work. The game’s title and other commercially valuable markers to identify the company’s works (such a recurring character or world within the game) can be protected with a trademark registration. The mask work registration, then, would be used to protect the ROM that contains binary code.

Ordinary copyright law applies to the underlying software (source, binary) and original characters and art. However, the enforcement of exclusive rights in a work distributed in the form of a mask ROM could depend on an untested interpretation of the originality requirement of § 902(b), which states: “(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.”

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. It is therefore essential to consult an Intellectual Property attorney to determine whether any potential mask work is eligible for protection under Chapter 9 of the Copyright Act. In fact, MVS has counseled many such companies on exactly that!

Finally, a special thanks to those that have read each of the Parts of this Series, which covers a very unique type of Intellectual Property protection in the United States not known to many. I therefore hope you enjoyed reading it as much as I enjoyed writing it!

Gregory Lars Gunnerson is an Intellectual Property Attorney in the Mechanical and Electrical Patent Practice Groups at McKee, Voorhees & Sease, PLC. For additional information please visit or contact Lars directly via email at

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