News Article
KLA-Tencor and Nikon develop automated overlay correction tools
KLA-Tencor Incorporated and Nikon Corporation have collaborated to develop a set of fully automated overlay correction control system tools, called Scanner Match Maker (SMM), that chipmakers can use to correct overlay errors common to ‘mix and match' lithography strategies which use lithography tools of varying capabilities and from different suppliers.
The SMM technology is aimed at elevating performance of all scanners, enabling chipmakers to reduce their dedication of leading-edge scanners to specific layers, thus cutting overall lithography tool costs at more advanced nodes and extending thelifetime of lithography tools.
"Because there are no automated correction systems commercially available for distortion control, KLA-Tencor and Nikon have each developed a complementary set of tools to enable a direct scanner-to-metrology system link for automating mix and match overlaycontrol," noted Ofer Greenberger, vice president and general manager of
KLA-Tencor's Overlay Metrology group.
"KLA-Tencor and Nikon will sell their respective correction tools directly to customers. This system is intended to be an open solution, enabling connection with scanners from other suppliers in the future. For this reason, SMM has a built-in security system to protect each scanner suppliers' proprietary information," he added.
For most chipmakers, the high cost of latest-generation lithography tools prohibits use of the most advanced scanners on non-critical layers, resulting in different layers being exposed with different tools. Each lithography tool has a different field distortion signature that, at the small dimensions of 45nm and beyond, can cause significant overlay error. With the fully automated procedure of SMM, different illumination conditions and combinations of multiple scanners can be tightly controlled, improving productivity, operating efficiency and cost of ownership in environments using a mix of immersion and dry tools, as well as leading-edge and non-leading edge tools.
Toshikazu Umatate, General Manager of Development Headquarters, Nikon Precision Company, said, "Today, chipmakers' overlay budget has almost no margin of error with regard to scanner alignment performance. Mix and match methods can cause scanner fleet alignment performance to be less than half that of dedicated, single-tool overlay operations, and mixing scanners from different suppliers make these errors are even more significant. Our SMM toolset is intended to help customers implement sophisticated correction procedures that can overcome inherent overlay errors caused by differences in tool distortion signatures, making it much easier to match a fleet of lithography tools.
"Currently under evaluation at a major semiconductor manufacturer in Japan and planned for release in the first calendar quarter of 2008, the SMM control system tools have demonstrated greater than 30% improvement in overlay accuracy vs. a mix and match technique without SMM.
