High Frequency Characteristics of Glass Interposer
Authors: Satoru Kuramochi, Masaya Tanaka, Miyuki Akazawa, Syohei Yamada Company: Dai Nippon Printing Co., Ltd. Date Published: 9/22/2019
Abstract: As electronic product becomes smaller and lighter with an increasing number of function,the demand for high density and high integration becomes stronger. Interposers for system in package will became more and more important for advanced electronic systems. Silicon interposers with through silicon vias (TSV) and back end of line (BEOL) wiring offer compelling benefits for 2.5D and 3D system integration; however, they are limited by high cost and high electrical loss. On the other hand, glass has many properties that make it an ideal substrate for interposer substrates such as; ultra high resistivity, adjustable thermal expansion (CTE) and manufacturability with large panel size. Furthermore, glass via formation capabilities have dramatically improved over the past several years. Fully populated wafers with >100,000 through holes (50µm diameter) are fabricated today with 300µm thick glass. The demand for high speed and large capacity in wireless communication devices is increasing more and more. Fifth generation wireless communication technology (5G) is actively being developed in order to meet these expectations. The application of glass interposer for integrated RF module requires ultra-low loss transmission characteristics. This paper presents the demonstration of glass interposers with fine pitch metalized through via. Twin types of Cu plating method with through via, full filling plating and conformal plating are compared with process capability using X ray observation. Electrical characteristics are measured with daisy chain test elementary vehicle. Excellent through via reliability was demonstrated at 200um pitch passed 1000cycle from -40 cereuses deg to 80 cereuses deg. We also studied the characteristics of TGVs on frequency up to 60GHz using 3D electromagnetic field analysis. High frequency transmission characteristics were measured with TGV co planer wave guide. High frequency transmission characteristics were measured with Twin types of TGV co planer wave guide.