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Tape-out


In electronics design, tape-out or tapeout is the final result of the design process for integrated circuits or printed circuit boards before they are sent for manufacture. The tape-out is specifically the point at which the graphic for the photomask of the circuit is sent to the fabrication facility.

Historically, the term references 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 (commonly Bishop Graphics crepe). In the post-war era of the 1940-50s, the techniques developed for rapid and low-cost circuit reproduction evolved to photographically replicated 2D manufacturing. The verb "tapeout" was already widely used lexicon for the process and adopted for transistor fabrication which evolved to full integrated circuit approaches. Pictured is the legendary Fairchild analog designer Bob Widlar with the manual tapeout of the LM10 opamp circa 1977.

The process advanced to adhesive-backed die cut elements on sheets of PET film (rubylith) wherein a dimensionally stable mylar layer was loosely adhered to a red layer which was selectively removed (high-resoulution monochrome photographic film of that era had optimal sensitivity to the red end of the spectrum). Initially rubylith was manually separated according to the engineers design parameters, and later automated via diamond-tip equipped x-y drafting machines driven by NC tape systems or direct computer output at the initial stages of the CAD revolution. Subsequently the artwork was photographically reduced. A similar process was used for early integrated circuits.

Some sources erroneously believe that the roots of the term can be traced back to the time when paper tape and later magnetic tape reels were loaded with the final electronic files used to create the photomask at the factory however the use of the term predates the widespread CAD usage of magnetic tape by decades.


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