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Understanding Mask Work

Mask work is a type of intellectual property protection designed to protect layout designs (topographies) of integrated circuits. It is authorized by the federal Semiconductor Chip Protection Act of 1984 (SCPA).

The SCPA legally protects layouts of integrated circuits upon registration, making them illegal to copy without permission. Under the SCPA, a mask work is a series of related images that forms a design or part of a design used to produce an integrated circuit. Registration of a mask work with the Copyright Office provides certain legal benefits, including the ability to bring a lawsuit for infringement of the mask work. Compendium: Chapter 1200, sections 1201-1202. Unlike copyrights, which are not necessarily registered with the United States Copyright Office (USCO), mask works must be federally registered in order to receive protection. Id, section 1203.

A registered mask work is protected for a period of 10 years after the date on which it is first registered with the United States Copyright Office or the date on which it is first commercially exploited, such as when it is first sold or otherwise used in commerce. Id, section 1206.

Registration of a Mask Work

The Mask Work Registration program at the U.S. Copyright Office allows individuals and organizations to register their mask works with the Office. To register a mask work with the Copyright Office, an applicant must submit a completed application, a nonrefundable filing fee (currently $150 according to, and a deposit of the mask work. The deposit can be either a physical copy of the mask work or a digital copy in a format specified by the Office.

The mask work owner has different options to deposit the mask work, depending on whether the mask work has been commercially exploited, or whether some portions of the mask work are trade secrets. In particular, Section 1213.2 of the compendium provides for redacted deposits containing trade secrets. It is recommended for the applicant to keep an unredacted version of the design along with the redacted version used for registration. During litigation, the unredacted version may be used as evidence to support the ownership of the redacted portions in the registered mask work.

Inspection of a Registered Mask Work

One of the biggest concerns for a mask work applicant is whether the registered mask work will be published or somehow made available to the public, thereby leading to copying/infringement. The Compendium published by the Copyright Office does not provide clarification on this issue. In summary, a registered mask work is subject to inspection, but under limited conditions.

The identifying material deposited to support an application to register a claim in mask work, whether the claim is registered or refused, becomes the property of the U.S. government. The U.S. Copyright Office will retain copies of all deposits for registered claims for the entire term of protection. 37 C.F.R. § 211.5(e). The U.S. Copyright Office allows authorized parties to view and inspect registered Mask Works just like the Office’s other public records. U.S. Copyright Office Services, chapter 2400, section 2407.

The deposited material of a mask work is subject to inspection under limited conditions:

  1. an individual/entity is allowed to make an appointment with the Copyright Office to inspect the deposited material by submitting a written request to the U.S. Copyright Office’s Records Research and Certification Section (RRCS). Id, section 2407.2(C). The individual/entity must physically appear at the Copyright Office in Washington D.C. to perform the inspection but is not allowed to make any copy of the deposited material of the registered Mask Work.
  2. when the mask work is involved in litigation. Id, section 2407.1(D)(2).
  3. when a court order is issued to inspect the deposited material of a mask work. Id.

Statistics from Copyright Office’s Annual Reports

Between 2010-2022, there are 646 mask works registered in the U.S. Copyright Office. Here is the number of mask works registered with the U.S. Copyright Office by year for the last 10 years. Source:

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Even though the number of registered mask works is not enormous, they are still an important component of chip companies’ IP portfolio. For example, Advanced Micro Devices (AMD) registered 191 mask works between 1990-2001. Source: official public catalog from


Considering the low cost of registering a mask work and the high value of IP protection that comes with the registration, we recommend our clients to register their semiconductor chip designs as mask works with the U.S. Copyright Office while register the software aspect of the designs (e.g., source code) under copyright law. The mask work deposits are in custody of the U.S. Copyright Office, there is no need to concern about the leakage of the deposits.