Laser dark-field illumination system modeling for semiconductor inspection applications

Dark-field defect inspection is an essential quality control method for the semiconductor fabrication industry, and it is broadly applied for micro particles detection in almost every fabrication process. Diode laser based dark-field illumination systems (LDFs) play a critical role in such illumination schemes due to its unique optical/mechanical properties. This paper discusses a complete LDF system model, includes the mathematical and optical descriptions of LDF system fundamentals. A series of trade-off curves are developed in this model, which describe system performance under different constraints. This model can either efficiently facilitate system design work for generic/unique applications, or can be used to evaluate existing LDF system performance.