A thermocompressive bonding method using a pure sputtered Au layer and its wafer scale package application

Abstract

The authors have developed a thermocompressive bonding method using a sputtered Au layer and applied it to the coplanar waveguide (CPW) package. The bonding temperature is 350 degrees C, the bonding pressure is 63 MPa, and the duration time is limited to 30 min. The bonding strength is evaluated using the Scotch tape and tweezers detaching method and the hermeticity is evaluated using helium leak detection work station. The measured hermeticity is 1.0x10(-9) Pa m(3)/s. To measure the electrical properties, the CPW line is packaged and the rf characteristics and dc resistance are measured. The insertion loss of the packaged CPW line is -0.074 dB at 2 GHz and the dc resistance is from 0.019 to 0.046 Omega. This result shows that their Au compressive bonding method is very useful and good for microdevice wafer level packaging applications. (c) 2008 American Vacuum Society.