Highly sensitive focus monitoring technique based on illumination and target co-optimization
| Autor: | Mark D. Smith, Pradeep Subrahmanyan, Ady Levy, Myungjun Lee |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Computer science
business.industry 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Metrology 010309 optics Optics 0103 physical sciences Wafer Computer vision Off-axis illumination Artificial intelligence 0210 nano-technology business ComputingMethodologies_COMPUTERGRAPHICS |
| Zdroj: | SPIE Proceedings. |
| ISSN: | 0277-786X |
| Popis: | We present a cost-effective focus monitoring technique based on the illumination and the target co-optimization. An advanced immersion scanner can provide the freeform illumination that enables the use of any kind of custom source shape by using a programmable array of thousands of individually adjustable micro-mirrors. Therefore, one can produce non-telecentricity using the asymmetric illumination in the scanner with the optimized focus target on the cost-effective binary OMOG mask. Then, the scanner focus variations directly translate into easily measurable overlay shifts in the printed pattern with high sensitivity (ΔShift/Δfocus = 60nm/100nm). In addition, the capability of using the freeform illumination allows us to computationally co-optimize the source and the focus target, simultaneously, generating not only vertical or horizontal shifts, but also introducing diagonal pattern shifts. The focus-induced pattern shifts can be accurately measured by standard wafer metrology tools such as CD-SEM and overlay metrology tools. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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