Advanced Silicon Interposer for High density and High Integration Electronic Packages

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. Interposers will be needed more complicated structure for 2.5D , 3D package and MEMS, OEMEMS new heterogeneous package structure Silicon interposers with through silicon vias (TSV) and back end of line (BEOL) wirring offer compelling benefits for 2.5D and 3D system integration; however, they are limited by high cost and high electrical loss. [1] This paper presents the demonstration of Silicon Interposers with fine pitch through Silicon vias(TSV),with embedded passive device. We have developed the TSV interposer with redistribution layers on both sides using MEMS technology, high aspect ratio deep etching technology and filled Cu plating with deep through holes for cost reduction and low electrical loss. The TSV interposer with 400μm thick high resistivity Si, obtained without backside processing use of carriers. Excellent through via reliability was demonstrated, due to double side thick polymer insulator that buffers the stress created by CTE mismatch between glass, copper vias and copper traces, and TSV at 200μm pitch passed 1000 thermal cycles from −55°C to 125°C. We have evaluated high frequency transmission characteristic of Si through hole by the measurement S21 parameter. Highly insulating TSV resulted in insertion loss of less than 1dB at 20GHz. Thin film SiN capacitor as embedded passive device was built in surface of TSV interposer by via first and via last method. The capacitance and leakage current of capacitor was measured and compared with two types of fabrication method.