Development of chip-on-flex bonding using Sn-based bumps and non-conductive adhesive |
| |
Affiliation: | 1. School of Electrical and Computer Engineering, University of Tehran, Iran;2. Department of EE-Systems, University of Southern CA, United States;3. Department of Electrical Engineering, Shahed University, Iran;1. Laboratoire Microélectronique et Instrumentation de Monastir (LR13ES12), Faculté des sciences de Monastir, Avenue de l''environnement, 5019 Monastir, Tunisia;2. Equipe composant Electronique de Nabeul (UR/99/13-22), IPEI Nabeul, Campus Universitaire El Merazka, 8000 Nabeul, Tunisia;3. Institut des Nanotechnologies de Lyon — UMR5270 (Site INSA), Campus La Doua, 69621, Cedex, France |
| |
Abstract: | We developed a reliable and low cost chip-on-flex (COF) bonding technique using Sn-based bumps and a non-conductive adhesive (NCA). Two types of bump materials were used for the bonding process: Sn bumps and Sn–Ag bumps. The bonding process was performed at 180 °C for 10 s using a thermo-compression bonder after dispensing the NCA. Sn-based bumps were easily deformed to contact Cu pads during the bonding process. A thin layer of Cu6Sn5 intermetallic compound was observed at the interface between Sn-based bumps and Cu pads. After bonding, electrical measurements showed that all COF joints had very low contact resistance, and there were no failed joints. To evaluate the reliability of COF joints, high temperature storage tests (150 °C, 1000 h), thermal cycling tests (?25 °C/+125 °C, 1000 cycles) and temperature and humidity tests (85 °C/85% RH, 1000 h) were performed. Although contact resistance was slightly increased after the reliability test, all COF joints passed failure criteria. Therefore, the metallurgical bond resulted in good contact and improved the reliability of the joints. |
| |
Keywords: | Chip-on-flex Non-conductive adhesive Sn-based bumps |
本文献已被 ScienceDirect 等数据库收录! |
|