Applied^® Sigmameltec^® MRC Mask Clean Series

Cleaning methods for photomasks used in 193i and EUV lithography are driven by sensitive mask materials and the environments in which the masks are used. Mask cleaning processes have evolved from aggressive chemical treatments to milder formulations combined with high frequency megasonics for removing smaller particles and achieving more pristine mask surfaces.

Sigmameltec’s MRC system provides mask makers with a toolset that can be adapted to their requirements, including a plasma chamber that gently yet effectively strips resist and removes residual organics. Two cleaning chambers served by a wet process robot provide segregation between chemical cleaning and the critical final cleaning steps. Available chemicals include ozonated water, CO₂ water, hydrolyzed water combined with TMAH, sulfuric-peroxide mixture and SC-1.

Key features and benefits:

• Downstream plasma for effective and damage-free removal of organic materials including carbon contamination on EUVL masks
• Process segregation between two wet chambers to optimize cleaning performance
• High frequency megasonic head with “acoustic brush” effect to efficiently dislodge minute particles without compromising fine mask features
• Linear slot nozzle with a uniform flow of ozonated water and in-situ UV irradiation for effective removal of organic materials
• Velocity impact nozzle with micron-scale droplets combined with chemistries to remove tenacious particles
• Vacuum bake chamber for surface preparation and ion removal
• Backside megasonic for high throughput, full mask cleaning without flip
• Sulfate-free and low ammonium processes to avoid haze formation on 193i masks