Abstract
Flip-chip bonding using a nonconductive adhesive (NCA) and the effect of solder wetting on NCA trapping were studied. Three different solder materials with different melting point were used for the bonding process: In–48Sn, Bi–42Sn, and Sn–3.5Ag. Additionally, the bonding process was performed at various temperatures. We measured the amount of NCA trapping as functions of the solder material and bonding temperature. The fillers and NCA were easily trapped between the solder and Cu pads. The amount of trapped fillers and NCA increased with softer solder materials. These trapped fillers and NCA could be reduced if the solder melted and reacted to Cu pads during the bonding process. However, if the solder melted after fully curing NCA, the trapped NCA was not reduced due to the low mobility of cured NCA. Therefore, in order to reduce NCA trapping, the solder should be melted before curing NCA. The electrical test results showed that the contact resistance increased with increasing amount of trapped fillers and NCA.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Materials Science: Materials in Electronics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.