3D chip fab: Detecting defects in TSVs

Rudolph Technologies announced the availability of its new SONUS Technology, designed for measuring thick films and film stacks used in copper pillar bumps and for detecting defects, such as voids, in through silicon vias (TSVs). SONUS Technology is a non-contact, non-destructive acoustic metrology and defect detection technique that is designed to be of higher resolution, faster, and less costly than alternative techniques.

Rudolph has collaborated with TEL NEXX specifically to develop pillar bump and TSV plating process control based on SONUS Technology.

“SONUS Technology meets a critical need for measuring and inspecting the structures used to connect chips to each other and to the outside world,” states Tim Kryman, Rudolph’s director of metrology product management. “Copper pillar bumps and TSVs are critical interconnect technologies enabling 2.5D and 3D packaging. Plating process control for copper pillar bumping is directly related to the mechanical integrity of the interconnect and final device performance. Likewise, the quality of the TSV fill is critical to the electrical performance of stacked devices. Rudolph’s patented SONUS Technology offers the unique ability to measure individual films and film stacks to thicknesses of 100µm and detect voids as small as 0.5µm in TSVs with aspect ratios of 10:1 or greater.”

Arthur Keigler, chief technology officer of TEL NEXX, said, “We’re attracted by the opportunity SONUS Technology offers our mutual customers in the advanced packaging market. The ability to measure multi-metal film stacks for Cu pillar, and then continue to use the same tool for TSV void detection offers immediate productivity and cost benefits to manufacturing and development groups alike."

Kryman adds, “SONUS Technology builds on the expertise in acoustic metrology developed for our industry-standard MetaPULSE systems used for front-end metal film metrology. Offering both improved time-to-profitability and yield improvement during high volume manufacturing (HVM) brings a compelling value proposition to advanced packaging customers. To that end, our relationship with TEL NEXX has been invaluable in bringing this technology to market.”