Simax has developed an extremely efficient and effective method to create overlay matching sets in a multi different brand exposure tool manufacturing process flow.

ASML 5500/100 Yield Improvement: Unique Overlay Matching Sets

Semiconductor wafer fab photolithography areas continually struggle with optimally overlay matching different brand photo exposure tools. This becomes extremely complex in a foundry or a manufacturing facility that only processes specific layers delivered from another company. In the past many manufacturing facilities were in-flexible and could not accept material patterned on other exposure tools due to the difficulty in controlling the specific overlay matching correction factors. The control of these correction factors was run under engineering control and was prone to data input errors and risk to standard product. Now manufacturers can accept wafers run on different brand exposure tools internally and externally by using unique matching set IDs. There can be multiple matching set IDs that optimally overlay match different tools sets. Examples of these unique matching sets might include [ASML-NIKON], [ASML-CANON4X], ASML5X-ASML4X], [ASML-ULTRATECH], and [ASML5X-NIKON25X]. These sets are developed to reduce concentric or non-concentric intra and inter field overlay errors resulting from the mixing of wafer patterns between the tools. The sets are activated within the job definition during a batch run and can be layer specific. This methodology is extremely efficient and effective in a multi different brand exposure tool manufacturing process flow.

ASML Match to Brand X Before and after matching (Note Vector Scales)

Diagram Source: HP

Overlay Error term improvement with custom matching set ID

This e-mail address is being protected from spambots. You need JavaScript enabled to view it. Simax Applications Engineering at simaxlithography.com for assistance in developing a custom overlay matching application for your process.

 Steve Brainerd is a Senior Applications Engineer with Simax Lithography. With over 30 years “hands-on” wafer fabrication experience concentrated in semiconductor wafer, MEMs, thick photoresist, solar, and LCD fabrication manufacturing processes, Steve uses his strong analytical skills to develop robust processes for customers. His knowledge and experience include process-equipment startup, process development, process modeling, anti-reflection coating design/modeling, cost reduction, yield improvement, and capacity increases.