Despite ample phenomenological evidence of reticle haze in IC manufacturing fabs, the mechanism of reticle haze formation is not well understood. Many attempts to control reticle haze formations are driven by trial-and-error approach and results are frequently contradicting and confusing.The authors apply extensive expertise of Airborne Molecular Contamination (AMC) measurement and control and DUV optics protection to develop a potential solution to the issue of 193 nm reticle haze. The authors outline the common mechanism of reticle haze formation and show that chemical modification of the reticle surface during mask manufacturing procedure is largely responsible for mask reticle susceptibility to AMC and surface molecular contamination (SMC). A proposed mechanism well explains available experimental and phenomenological data and the differences seen in chemical compositions of the haze particles observed at different fabs. The authors propose a single elegant solution for controlling multiple types of haze. Effectiveness of this solution is demonstrated through the field data obtained from production fabs.
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