Scratching the surface

Developing a custom purge system for a solar cell wet processing tool using special solvents to surface-treat silicon wafers.

Project brief

• To develop a special purge system for a photovoltaic cell wet process tool with two separate purging functions during the operating cycle.

Challenges:

• Space limitations - the process equipment had limited space available inside for the purge system, so a compact solution was a must
• Environment - the wet process used a proprietary blend of solvents that was both corrosive & flammable 
• Control - the purge system was required to interface with the process tool software for activation and operating mode selection

Outcome:

• A highly custom, twin parallel MiniPurge system on a special chassis to fit the allocated space
• Teflon process connections to reduce the risk of corrosion in the event of any back-migration of solvent vapour
• Purge system interlocks to the process tool control system for purge mode selection and stop/start
• Purge flow measurement close to the process chambers using special teflon orifice devices feeding back to the MiniPurge