COB bonding (ACF)
Bare chip bonding on the board
COB is an acronym for Chip On Board. A general term for technologies for bonding chips on a board (PCB board).
Since the semiconductor bare chip is bonded directly on the substrate, space-saving bonding and low-profile bonding are possible compared to bonding packaged products.
There are various methods for connecting to the board, and one of them is ACF bonding. Place the ACF on the board and mount the chip on it with flip chips. The chip is bonded on the board by thermal crimping of ACF.
It is suitable for adhesion between ICs and boards that require continuity between opposing circuits and insulation between adjacent circuits.
ACF (= Anisotropic Conductive Film) is an abbreviation for Anisotropic Conductive Film, which is a sealing resin in which conductive particles are dispersed in a thermosetting epoxy resin. By heat crimping, it exhibits electrical anisotropy that maintains conductivity in the thickness direction and insulation in the plane direction at the crimped part.
ACF contributes to the miniaturization and thinning of electronic components.
When bonding an electronic component, ACF is sandwiched between the electrode part of the printed circuit board and the electrode part of the component, and the component is pressurized while applying heat. Then, the conductive particles dispersed in the film are crushed between the electrodes and eventually form a conductive path. Uncrushed particles remain dispersed in the resin, preserving insulation. As a result, an anisotropic conductive path is formed between the electrodes in the vertical direction and insulating from the adjacent electrodes in the horizontal direction. In addition, the resin in the ACF is cured to hold the conductive particles and mechanically fix the bonded parts.
This makes it possible to mount electronic components without causing a short circuit even if the distance between the electrodes in the lateral direction is narrow.
We accept ACF (anisotropic conductive film) bonding prototypes!
Please feel free to contact us from the inquiry page.