In United States intellectual property law, a "mask work" is a two or three-dimensional layout or topography of an integrated circuit (IC or "chip"), i.e. the arrangement on a chip of semiconductor devices such as transistors and passive electronic components such as resistors and interconnections. The layout is called a mask work because, in photolithographic processes, the multiple etched layers within actual ICs are each created using a mask, called the photomask, to permit or block the light at specific locations, sometimes for hundreds of chips on a wafer simultaneously.

Because of the functional nature of the mask geometry, the designs cannot be effectively protected under copyright law (except perhaps as decorative art). Similarly, because individual lithographic mask works are not clearly protectable subject matter; they also cannot be effectively protected under patent law, although any processes implemented in the work may be patentable. So since the 1990s, national governments have been granting copyright-like exclusive rights conferring time-limited exclusivity to reproduction of a particular layout. Terms of integrated circuit rights are usually shorter than copyrights applicable on pictures.

International law.

A diplomatic conference was held at Washington, D.C., in 1989, which adopted a Treaty on Intellectual Property in Respect of Integrated Circuits, also called the Washington Treaty or IPIC Treaty. The Treaty, signed at Washington on May 26, 1989, is open to member states of the United Nations (UN) World Intellectual Property Organization (WIPO) and to intergovernmental organizations meeting certain criteria. The Treaty has been incorporated by reference into the TRIPS Agreement of the World Trade Organization (WTO), subject to the following modifications: the term of protection is at least 10 (rather than eight) years from the date of filing an application or of the first commercial exploitation in the world, but Members may provide a term of protection of 15 years from the creation of the layout-design; the exclusive right of the right-holder extends also to articles incorporating integrated circuits in which a protected layout-design is incorporated, in so far as it continues to contain an unlawfully reproduced layout-design; the circumstances in which layout-designs may be used without the consent of right-holders are more restricted; certain acts engaged in unknowingly will not constitute infringement.

The IPIC Treaty is currently not in force, but was partially integrated into the TRIPS agreement.

Article 35 of TRIPS in Relation to the IPIC Treaty states:

Members agree to provide protection to the layout-designs (topographies) of integrated circuits (referred to in this Agreement as "layout-designs") in accordance with Articles 2 through 7 (other than paragraph 3 of Article 6), Article 12 and paragraph 3 of Article 16 of the Treaty on Intellectual Property in Respect of Integrated Circuits and, in addition, to comply with the following provisions. TRIPS Document

Article 2 of the IPIC Treaty gives the following definitions:

(i) 'integrated circuit' means a product, in its final form or an intermediate form, in which the elements, at least one of which is an active element, and some or all of the inter-connections are integrally formed in and/or on a piece of material and which is intended to perform an electronic function,

(ii) 'layout-design (topography)' means the three-dimensional disposition, however expressed, of the elements, at least one of which is an active element, and of some or all of the interconnections of an integrated circuit, or such a three-dimensional disposition prepared for an integrated circuit intended for manufacture ...