In
integrated circuit design
Integrated circuit design, semiconductor design, chip design or IC design, is a sub-field of electronics engineering, encompassing the particular Boolean logic, logic and circuit design techniques required to design integrated circuits (ICs). A ...
, full-custom is a design methodology in which the layout of each individual
transistor
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...
on the
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
(IC), and the interconnections between them, are specified. Alternatives to full-custom design include various forms of semi-custom design, such as the repetition of small transistor subcircuits;
[{{cite book , title = The VLSI handbook , author = Rajneesh kaswan , publisher = CRC Press , year = 1999 , isbn = 0-8493-8593-8 , url = https://books.google.com/books?id=0r5LihlMogkC&q=%22full+custom+design%22&pg=PT853 ] one such methodology is the use of
standard cell libraries (which are themselves designed full-custom).
Full-custom design potentially maximizes the
performance
A performance is an act or process of staging or presenting a play, concert, or other form of entertainment. It is also defined as the action or process of carrying out or accomplishing an action, task, or function.
Performance has evolved glo ...
of the chip, and minimizes its area, but is extremely labor-intensive to implement. Full-custom design is limited to ICs that are to be fabricated in extremely high volumes, notably certain
microprocessor
A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...
s and a small number of
application-specific integrated circuit
An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficienc ...
s (ASICs).
As of 2008 the main factor affecting the design and production of
ASICs was the high cost of
mask sets (number of which is depending on the number of IC layers) and the requisite
EDA design tools. The mask sets are required in order to transfer the ASIC designs onto the
wafer.
See also
*
Electronics design flow
References
Integrated circuits