Evaluation of die to organic laminate to PCB interconnects up to 50GHz

Abstract

Ceramic substrates have traditionally been used in RF and microwave packaging applications because of the electrical properties at high frequencies. However, there is significant interest in using organic laminates due to its tighter wiring ground rules for high density packaging and lower cost of fabrication. The high frequency performance of interconnection from die to PCB using an organic packaging substrate has not yet been studied in detail. In this work, the interconnect performance of die to organic laminate to PCB up to 50 GHz was modeled and characterized using a test vehicle assembly. The test vehicle was specifically designed with test pads to characterize the interconnect performance at multiple levels of interconnection. A comparison study using a ceramic package substrate was also carried out. The modeling and hardware testing results from this study showed −3dB bandwidth of more than 50GHz for printed circuit board (PCB) to organic laminate and a bandwidth of 40GHz for the die to organic laminate to PCB interconnection. The results from this study showed that the organic laminate demonstrated a high frequency performance comparable to that of the ceramic substrate, which makes it suitable as a packaging substrate material for high frequency applications.