Abstract

A novel no-flow underfill material for advanced flip chip and CSP packaging has been successfully developed. This new material is based on a non-anhydride resin system and therefore it does not have the chemical sensitizing concern. Unlike the short pot life of most anhydride systems this new material exhibited excellent pot life. The viscosity of the material did not increase over 48 hours at room temperature. During the assembly process, the material demonstrated that it fluxed the solder bumps, formed a nice fillet, and was fully cured during a single reflow exposure. Production efficiency is therefore significantly increased. In addition, the assembled packages using this novel no-flow underfill material also achieved high interconnect yield. In this paper, we present the curing kinetics study and material properties of this novel no-flow material. The influence of fluxing agents on curing kinetics of this system is discussed. Material properties such as glass transition temperature (Tg), modulus, and viscosity were systematically characterized. Differential scanning calorimetry (DSC) dynamic-mechanical analysis (DMA), and rheometry were used for this study. In addition, promising assembly trial results, using small flip chips (PB8) and CSPs (TV46), are reported. Finally, the effects of the formulations and reflow profile on voiding and yield are also discussed.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

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.