Photoimageable auto-catalytic resin metallization as an alternative to sputtering

In order to miniaturized mobile phones, PDAs, and other handheld electronic devise, the use of wafer level packaging such as MCP and SIP with various functionalities has increased significantly. Polyimide, BCB, and epoxy resin systems are widely used as dielectric redistribution materials. Sputtering has been the metallization technology of choice for UBM and seed layers. However, the high cost and poor adhesive reliability are issues with sputtering reliability are issues with sputtering as a metallization technology. As an alternative to sputtering technology, a photoimageable auto-catalytic resin (PAR) has been designed that enables the electroless metallization of a wide variety of substrates, including WL-CSP dielectrics such as polyimide film, glass, and ceramics. PAR also enables interconnects with excellent electrical and adhesive reliability. This paper focuses on the properties and reliability of PAR materials as a new metallization technology.