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|High Volume Manufacturing Considerations forCopper Electrodeposition for Through Silicon Via Integration|
|Keywords: Integration, Systems, Controls|
|This presentation will focus on the integration and production challenges of electrochemical deposition (ECD) of copper for through silicon via (TSV) applications; a technology that has become a main focus of advanced packaging strategies and is transitioning to R&D production. TSV ECD has relatively long processing times compared to Damascene plating, requiring processes and control methods that will meet customer needs for both on-wafer performance and cost. ECD copper performance relies, not only on control of the deposition, but also on external influences from the entire TSV manufacturing module. Via size and aspect ratio are recipe requirement drivers and this currently remains specific to the customer application and varies widely. Line stability and upstream unit processes also influence how the copper deposition is controlled. Downstream CMP requirements for minimal overburden must be considered during process development and controlled during production. The end requirements for successful TSV deposition are void-free fill with minimal and stable stress, impurities and consistent overburden. To meet these goals in high volume manufacturing (HVM) a tightly controlled process with a wide process window and a versatile toolset are three key goals. Production toolsets must maintain high uptime and throughput requirements. With deposition recipes that may run for up to several hours, the number of ECD reactors should match throughput requirements which requires multiple available processing chambers. This also influences bath control as maintenance, automatic dosing and analysis must all occur during production. Methods for controlling dosing and replenishment will be discussed. Process windowing limits must be established and control schemes designed to fit into those limits. Process monitoring is required and used to track process performance using relevant metrology and tracked using statistical process control (SPC) methods for a variety of parameters and wafer results.|
|Bridger Hoerner, Process Engineer
Applied Materials - Semitool Business Unit