Flip chip is a method used for components or devices that can be bonded directly onto a substrate, board or carrier face-down. The connection is made through conductive bumps placed on the surface of the die. The placing process amounts to the following:
1. Die is picked up and place on a "flipping device"
2. Die is "flipped" and moved to hover over the substrate (or board or carrier) where bumps reside - precisely positioned in their previously defined positions
3. The tool then places the die on the bump with a programmed amount of force
Flip chip bumping is a vital step to the process. The bump provides the necessary electrical connection between the die and the substrate, provides thermal conduction through the two materials, acts as a "spacer" to prevent electrical shorts and provides mechanical support.
Flip chips avoid wire bonding and therefore are able to be much smaller than their counterparts. Flip chip processes have been around for more than 40 years. Since then, thousands of applications have taken advantage of the size and cost benefits enabled by the flip chip assembly method.
For precision flip chip processes, a lookup camera and lookup camera software greatly increase the level of precision and accuracy.