RDL Multilayer Metallization Approaches for TGV

Significant advances have been accomplished in the field of Through Glass Via (TGV) technology; enabling a new generation of electronic designs that achieve higher performance, while leveraging low cost system solutions. Through-hole creation methods in glass have been optimized for mass production with consistent via diameter, shape and wall chemistry/morphology. This has enabled the development of unique copper via metallization materials that exhibit very high conductivity, thermal expansion matching and hermeticity. This paper will discuss post via metallization processes for multilayer RDL (Redistribution Layer) metallization on both sides of the glass wafer. Unique Chemical Mechanical Polishing (CMP) development approaches for glass wafers with copper thick film vias will be explained. Thin film deposited adhesion layer on glass, followed by a deposited metallization layer will be described. Types of deposited adhesion layer on glass for optimized adhesion and electrical contact with the vias will be examined. Furthermore, copper plating approaches for higher conductivity and fine line circuit patterning are examined. Polymeric dielectric material systems for multilayer RDL on both sides of the glass will also be reviewed.