Superior electrical properties of High Performance Glass Ceramic packaging for demanding SiGe, ASIC, microprocessor and advanced server applications

Abstract

IBM's High Performance Glass Ceramic (HPGC) LTCC modules are used in a wide range of SiGe, ASIC, microprocessor and advanced server applications in SCM and MCM configurations. Electrical test structures are designed and electrically modeled to provide guidance for producing parts on high volume manufacturing tools. Substrates are characterized at frequencies from DC to 40 GHz in microstrip and stripline environments for single ended and differential transmission line elements. Test structures include High Speed Serial link core compatible designs, controlled impedance via (CIV) structures, and designs to minimize line-via signal impedance / mode transition discontinuities. Material properties thermal solutions are characterized to simulate high power application environments. The beneficial attributes of designs with various transmission line structures are described, as are the advantages derived from uniformly thick, symmetric, reproducible, and smooth surface copper conductors for signal routing and shielding planes. This work reflects the use of both IBM produced and non-IBM electrical modeling tools. These tools include ANSOFT HFSS, HSpice and IBM tools such as CZ2D and EMITPKG. It will be shown how the suite of tools has been used to optimize design structures for optimum electrical performance of glass ceramic packaging for low and high speed applications. Correlation of design models to finished product are demonstrated with electrical measurement data obtained with both time-domain and frequency-domain techniques.