Title :
Novel flip-chip bonding technology for W-band interconnections using alternate lead-free solder bumps
Author :
Onodera, K. ; Ishii, T. ; Aoyama, S. ; Sugitani, S. ; Tokumitsu, M.
Author_Institution :
Photonics Labs., NTT Corp., Kanagawa, Japan
Abstract :
A novel lead-free flip-chip technology for mounting high-speed compound semiconductor ICs, which have a relatively severe limitation regarding high-heat treatment, is presented. Solder bump interconnections of 0.95Sn-0.05Au were successfully fabricated by reflowing multilayer metal film at as low a temperature as 220/spl deg/C. The bumps were designed to have a diameter of 36 μm with a gap between the chip and the motherboard of 24 μm. The electrical characteristics of flip-chip-mounted coplanar waveguide chips were measured. The deterioration in reflection loss in the flip chip mounting was less than 3 dB for frequencies up to W-band.
Keywords :
coplanar waveguides; flip-chip devices; gold alloys; high-speed integrated circuits; integrated circuit bonding; integrated circuit interconnections; microwave integrated circuits; millimetre wave integrated circuits; reflow soldering; tin alloys; 220 C; 24 micron; 36 micron; GaAs; GaAs-based devices; InP; InP-based devices; Pb-free solder bumps; Sn-Au solder bump interconnections; SnAu; W-band interconnections; bump diameter; chip motherboard gap; electrical characteristics; flip-chip bonding technology; flip-chip-mounted coplanar waveguide chips; high-speed compound semiconductor ICs; lead-free flip-chip technology; lumped element microwave circuits; multilayer metal film reflow; reflection loss deterioration; Bonding; Coplanar waveguides; Electric variables; Electric variables measurement; Environmentally friendly manufacturing techniques; Lead compounds; Nonhomogeneous media; Optical films; Semiconductor films; Temperature;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2002.804555
