Applied^® Sigmameltec^® SFD Mask Develop Series

Accurate development of the exposed resist pattern is essential to preserving the inherent CD uniformity of a photomask that has gone through highly controlled processes for coat, expose and bake. This requires uniform and simultaneous dispensing of the developer over the mask surface. A sufficient flow rate is needed to avoid developer depletion and to achieve optimal CD linearity over the full range of mask feature sizes. Mask defects must be avoided by separating chemical steps and preventing droplets from rebounding onto the mask surface.

Sigmameltec’s SFD system design is based on two chambers that separate the develop and final rinse steps, combined with a wet mask transfer between chambers to avoid drying between the post-develop rinse and the final rinse steps. Exact control of developer temperature and flow rate ensures CD mean stability from mask to mask. A wide chamber with smooth walls and dual height zone processing prevents splash-back onto the mask, and chamber and stage rinsing maintain the consistent cleanliness required for defect-free mask processing.

Key features and benefits:

• Develop and final rinse chambers segregate chemicals to avoid cross-contamination and defects
• Dual height zones in wet chambers and a smooth chamber design eliminate splash-back
• Wide linear slot nozzle ensures a uniform flow of developer for optimal CD uniformity and mean CD repeatability
• High flow rate with feedback loop control minimizes loading effects and optimizes CD linearity
• Separate rinse nozzle provides quick quenching of develop process for best CD control
• Wet robot transfers mask with intact puddle, avoiding premature drying and protecting mask features
• Backside nozzle provides simultaneous rinse of entire mask
• Automated chamber and stage rinse maintains a clean environment without operator intervention