A study on inconsistent epoxy dispense in the application of capillary underfill processes

The capillary underfill process is a method of applying epoxy using capillary action to attach a flip chip onto a substrate. The epoxy is dispensed on one side of the chip and the capillary motion draws the epoxy through the bottom layer of the chip. Inconsistent epoxy dispensing becomes an issue as permanent chip attachment is based on a constant layer epoxy on the substrate. The two variables used in detecting inconsistent epoxy dispensing are the measures of epoxy shot weight and dispense peak temperature, which is currently seen to be out of control. This study would include all methods of identifying the most important root causes of this issue and proposing possible and achievable solutions to ensure the quality control of the mass-produced units passing through the capillary underfill module.