Processability and reliability of nonconductive adhesives (NCAs) in fine-pitch chip-on-flex applications |
| |
Authors: | W K Chiang Y C Chan Brian Ralph Andrew Holland |
| |
Affiliation: | (1) Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong;(2) School of Engineering and Design, Brunel University, Uxbridge, Middlesex, United Kingdom |
| |
Abstract: | The use of NCAs to form direct contact interconnections between chip bumps and substrate pads have become a viable option
in interconnection technology for fine-pitch applications. However, the primary concerns with NCAs are their long-term reliability,
stability, and consistent electrical performance in particulate interconnections. Results of assembly process studies and
environmental testing using NCAs on flexible substrates are analyzed and discussed herein. An extensive design experiment
was performed to determine which process parameters were critical in obtaining good electrical connections. A reliability
evaluation of NCAs for flexible substrate applications was carried out to gain more insight into the failure mechanisms of
this type of interconnect. Pressure cooker test results showed that failures occurring in NCA joints are primarily due to
moisture absorption, which could lead to interfacial delamination at the substrate/adhesive interface, accompanied by hygroscopic
swelling. NCAs with lower coefficients of thermal expansion also exhibited better contact resistance stability during high-temperature
storage tests. |
| |
Keywords: | Fine pitch nonconductive adhesive NCA reliability contact resistance |
本文献已被 SpringerLink 等数据库收录! |
|