Improved multi-layer packaging

摘要

A multi-layered package is disclosed that employs novel shielding techniques to improve high frequency performance of the package. Shield vias (204) are placed near conductive vias (200) to create a two-wire transmission line with controllable characteristic impedance. Controlled transmission line impedance reduces signal reflection due to line impedance variations and ground bounce due to inductive coupling. Opposite polarity shielding technique is introduced in vertical as well as horizontal directions to reduce capacitive coupling of noise between signals and provide immunity against differential power supply noise. Signal layers disposed half way between floating shield planes provided immunity against non-common mode noise coupling. For integrated circuits with varying types of signals (e.g. CMOS and TTL and ECL type signals), the package creates electrically isolated zones to drastically reduce noise coupling between the circuits with different signal types.