Tape-out
In electronics design, tape-out or tapeout is the final result of the design cycle for integrated circuits or printed circuit boards, the point at which the artwork for the photomask of a circuit is sent for manufacture.[1]
The roots of the term can be traced back to the early days of printed circuit design, when the enlarged (for higher precision) "artwork" for the photomask was manually "taped out" using black line tape and adhesive-backed die cut elements on sheets of PET film. Subsequently the artwork was photographically reduced.[2] A similar process was used for early integrated circuits.[3]
The term tapeout currently is used to describe the creation of the photomask itself from the final approved electronic CAD file. This stage is sometimes referred to as PG, for Pattern Generation. Designers may use this term to refer to the writing of the final file to disk or CD and its subsequent transmission to the foundry; however, in current practice the foundry will perform checks and make modifications to the mask design specific to the manufacturing process before actual tapeout. Optical proximity correction is an example of such an advanced mask modification; it corrects for the wave-like behavior of light when etching the nano scale features of the most modern integrated circuits.[1]
A modern IC has to go through a long and complex design process before it is ready for tape-out. Many of the steps along the way utilize software tools collectively known as electronic design automation (EDA). The design must then go through a series of verification steps collectively known as "signoff" before it can be taped-out. Tape-out is usually a cause for celebration by everyone who worked on the project, followed by trepidation awaiting the first article, the first physical samples of a chip from the manufacturing facility (semiconductor foundry).
First tapeout is rarely the end of work for the design team. Most chips will go through a set of spins where fixes are implemented after testing the first article. Many different factors can cause a spin, including:
- The taped-out design fails final checks at the foundry due to problems manufacturing the design itself.
- The design is successfully fabricated, but the first article fails functionality tests.
References
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zh:下線- ↑ 1.0 1.1 "What the Hell is… a tapeout?", The Register, 14 July 1999
- ↑ "Follow Heuristic Guidelines To Make Surface-Mount PC-Board Footprints", Electronic Design, March 16, 2006
- ↑ The Essential Guide To Semiconductors, Jim Turley, Prentice Hall PTR, 2002, p.37
