Technical Library | 2013-08-29 19:52:43.0
Au over Ni on Cu is a widely used printed circuit board (PCB) surface finish, under bump metallization (UBM), and component lead metallization. It is generally accepted that less than 3 wt.% Au in Sn-Pb solder joints inhibits formation of detrimental intermetallic compounds (IMC). However, the critical limit for Au content in Pb-free solder joints is not well established. Three surface-mount package platforms, one with a matte Sn surface finish and the others with Ni/Au finish, were soldered to Ni/Au-finished PCB using Sn-3.0Ag 0.5Cu (SAC305) solder, in a realistic manufacturing setting. The assembled boards were divided into three groups: one without any thermal treatment, one subjected to isothermal aging at 125°C for 30 days, and the third group aged at 125°C for 56 days...
Technical Library | 2015-09-23 22:08:32.0
A molded interconnect device (MID) is an injection molded thermoplastic substrate which incorporates a conductive circuit pattern and integrates both mechanical and electrical functions. (...) Flip chip bonding of bare die on MID can be employed to fully utilize MID’s advantage in device miniaturization. Compared to the traditional soldering process, thermo-compression bonding with gold stud bumps provides a clear advantage in its fine pitch capability. However, challenges also exist. Few studies have been made on thermocompression bonding on MID substrate, accordingly little information is available on process optimization, material compatibility and bonding reliability. Unlike solder reflow, there is no solder involved and no “self-alignment,” therefore the thermo-compression bonding process is significantly more dependent on the capability of the machine for chip assembly alignment.
| 1 |
