Chip on Film or Flex
COF (chip on film or flex) technology is mainly used in display components, among them PDP (plasma display), flat panel displays and other product driver IC assembly are mostly used. It also used in the mobile phone display panel thanks to its resolution, thin, simple and other factors.
Like TAB and COG, COF also can be used in light and small products. Films of COF can not only bond ICs, also can solder other components like resistors, capacitors, etc., on the circuits if required. Even more, it can reduce the IC-related circuits space, in addition to the parts area can not be folded, the remaining parts are all foldable.
COF's simple structure, automatic production, and reduced labor costs, all reduce Module costs, and so far their reliability is still higher than that of COG (eg, thermal shock, constant temperature and humidity, etc.). The biggest difference between the TAB Tape and COF is that COF is a two-layer structure (Cu+PI) without component hole, the overall thickness is much thinner with better flexibility and better peel strength. Thus it is the main trend of development for a soft packaging substrate.