Pros and cons of laser C2 reflow process by high power diode laser

As the I/O density and speed of electronic devices increase dramatically, fine pitch copper-pillar flip chip becomes a very popular choice of technology for high density interconnects. The bonding processes for these packages are classified as post-applied underfill bonding processes and pre-applied underfill bonding processes [1-3]. These bonding processes have been studied intensely. Robustness of the bonding process and integrity of resulting solder joints are critical to ensure high assembly yield and high product reliability. On the other hand, these assembly processes have to achieve reasonable throughput in order to lower the assembly cost.