There are four common uses of polyimide coatings that thin film circuit designers should be aware of:
SOLDER DAMS – A polyimide solder dam is a strip of material placed strategically across lines or pads to stop the flow of solder from one location to another.
CROSS-OVERS – In Lange Couplers and similar devices where there is a need to replace wirebonds with a robust cross-over, we often use polyimide as a permanent cross-over. Cross-overs supported by polyimide provide a rugged, highly reliable structure.
MECHANICAL PROTECTION LAYER – Polyimide is very useful as a mechanical protection layer. It is used to protect fine pitch or critical circuit areas from assembly damage.
MULTILAYER – Polyimide offers the ability to build up multiple layers of circuitry and dielectric on thin film circuits on ceramic, thus providing the ultimate process for reducing size and increasing signal speed.