Process and productivity results from a carrier-based linear transport PVD system for RDL seed layer deposition in fan-out packaging applications

Carrier-based linear transport sputter deposition systems are routinely used in the silicon photovoltaic (PV) cell industry owing to the demonstrated usefulness of such systems in the High Volume Manufacturing (HVM) of silicon PV cells, where throughputs of thousands of wafers per hour are expected, and where Cost-of-Ownership (COO) differences of pennies per PV wafer can make or break a manufacturer. The metals being sputter deposited for silicon PV cells are typically some combination of Ti, TiW, Al, and Cu - the same materials that the Advanced Packaging industry uses for barrier/seed structures in Cu Redistribution Layers (RDL). In Fan-Out Wafer Level Packaging (FOWLP) today, cluster tool architectures from front-end semiconductor fabrication are the Process-of-Record (POR) configuration for RDL barrier and seed deposition. We present here details about barrier/seed layer processes for Fan-Out RDL developed on a carrier-based linear transport Physical Vapor Deposition (PVD) system, including metal film uniformity, sheet resistance, and film adhesion results for both 300mm round fan-out wafers and for 600mm × 600mm square fan-out panels. We also present our analysis of system throughput, PVD target utilization, and overall COO, as compared to the metrics characteristic of a typical PVD cluster tool.