Manufacturability Study of LTCC Integrated Packages for High Performance, Low Cost RF SiP Modules

摘要

This paper presents an extensive study conducted on a variety of commercially available LTCC material system The purpose of the study was to evaluate the comparative quality of LTCC substrates with embedded RF components, for a System-in-Package (SiP) module. The module has a flip chip IC and EGA contacts, and is designed as a highly integrated receiver for the radio section of a CDMA mobile phone handset. In Part 1 of this study, measurements of defect rates and the variation in both physical and electrical (DC and RF) performance characteristics were collected and compared on samples produced by several (up to 7) different commercial LTCC foundries. Statistically significant sample sizes of specially designed PCM (Process Control Monitor) test structures were tested and analyzed. Part 2 of the study used a custom SEC (Standard Evaluation Circuit) module substrate designed and fabricated in LTCC. The samples were processed through a high volume SiP assembly line to evaluate the compatibility of each type of LTCC with flip chip and EGA processes in a true manufacturing environment. During Part 3 of the study, statistics were collected on the reproducibility of the embedded components produced by a single LTCC supplier across multiple manufacturing lots. Each part of the study revealed significant differences between LTCC material systems, both in the level of process control when fabricating embedded passive structures, and in their compatibility with standard assembly processes.