Semicustom (Application-Specific) Integrated Circuits - ASICs

Because physical implementation on full custom ICs is so costly and time consuming, semicustom IC types evolved during 1980s and 1990s to reduce the costs and the time of fabricating a chip. These types are known as application specific integrated circuits or ASICs. An ASIC is somewhat customized, hence the term semicustom and the customization is specific for a particular circuit application, hence the term application - specific.

The distinction is akin to that between full-custom and semicustom houses. The former involves custom designing every aspect of a house and is thus expensive, time consuming and rare while the latter incolves adjusting a basic design and is less costly, faster to build and far more common. Two common ASIC types are standard cell and Gate array.