About COF
COF is an acronym for Chip On Film, which is a bonding that mechanically fixes a semiconductor chip on a film while providing electrical continuity.
It seems that COF bonding is used instead of COG bonding on glass for driver IC bonding in displays that support narrowing the frame.
COF example
In the case of COB (Chip on Board), there are various connection methods such as wire bonding and ACF connection even if it is called COB, but COF seems to refer to bonding by ACF connection. (It is possible to perform wire bonding on FPC, but since there are not many examples, COF is usually chip bonding on FPC by ACF.)
Since it is an ACF connection, the chip and FPC are electrically connected, and at the same time, they are mechanically fixed.
Of course, since it is on a flexible FPC, if stress is applied, the FPC will come off or the IC will crack. Therefore, it is necessary to be careful when handling it by the customer after bonding.
Most of the COFs are used to bond driver ICs for displays. Since an IC with a very large number of terminals will be bonded, the FPC may have a wiring pitch of 30 to 40 um. The IC is bonded on such a fine pitch FPC with high accuracy.
Ings Shinano flexibly supports COF bonding from several prototypes to mass production in small quantities. Please feel free to contact us from the inquiry page.