A Low Cost Wafer Scale Package Technology for mm-wave Applications

I. INTRODUCTION

The availability of low-cost, high performance amplifiers is crucial to the continued development of mm-wave commercial applications from 17 to 40 GHz. Typical applications include wireless data links such as Local Multipoint Distribution Service (LMDS) and point-to-point microwave radio as well as automotive 24GHz, instrumentation, and VSAT satellite ground stations. Recent industries’ technical trend for mm-wave MMICs is using surface mount packages for assembly cost reduction. Typical high frequency packages are Rogers 4003 material for SMT packages [1], plastic material for QFN packages [2] and liquid crystal polymer material for SMT packages [3].

No matter what packaging techniques are used, conventional packages require assembling processes such as die attaching, wire-bonding, and lid attaching. Those assembly processes are key bottlenecks for the cost reduction. To realize radical manufacturing cost reduction, we propose a wafer scale packaging technique for mm-wave MMIC manufacturing. There are some technical challenges to realize wafer scale package for mm-wave MMIC applications. RF interface must be optimally designed to obtain good 50-Ohm matching.

MMIC design must be considered for the proximity effect from a capping wafer. The amplifier shown in this paper was carefully designed to realize optimum performances in wafer scale package environment.