Reduction of airborne molecular contamination on an extreme ultraviolet reticle dual pod using clean dry air purging technology

• The new EUV dual is compliant with SEMI Standard E152-0214.
• CDA purging is an effective method to retard AMC in wafers in the wafer EUV pod.
• The 2 inlet and 2 outlet arrangement were found to be the most efficient.

SEMI Standard E152-0214 requires that detailed physical structure and interface analysis would be carried out for the design of extreme ultraviolet (EUV) pods. However, specific requirements for the structure's design, performance characteristics and testing and evaluation methodology are not included in the aforementioned document. Also it is impractical to incorporate the existing immersion lithography technology in the design of the new EUV pod. Few previous studies appear to have reported the related research.Clean dry air (CDA) purging has been proved to be an effective method to retard the haze formation on wafers in the wafer EUV pod, which is caused by deposition of airborne molecular contamination (AMCs) on wafer surfaces.Chemiluminescence (CL) spectroscopy and Photoionization detector (PID) techniques were used to measure AMCs and evaluate the purging effect of varying numbers of inlet and outlet arrangements in the EUV pod. Among these, the 2 inlets and 2 outlets arrangement was found to be the most efficient, providing a purging flow rate of 16 l per minute (LPM).

NH3 concentration decay profiles under different CDA purging flow rates.C7H8 concentration decay profiles under different CDA purging flow rates.Figure optionsDownload as PowerPoint slide