Application Examples: Automated Wafer Handling and Inspection System

AEi developed a fully automated vision guided wafer handling and inspection stations for photovoltaic (solar) cell production.

Products & Platforms:

• FlexAuto

Processes & Tools:

• Laser Processing
• Machine Vision Guided Automation

Application Requirements:

• Automated vision-based wafer inspection
• Vision guided motion to place wafers precisely into the carrier and boxes
• Password protected HMI screens that allow the customer to easily modify machine parameters for maximum flexibility
• Monitoring of inputs, control of outputs, and servo motor coordination
• Wafer lot tracking and logging
• Communications, coordination, and reporting to other controllers on the production line

AEi developed a fully automated wafer handling system to load, unload and inspect each wafer twice: once before loading, then again as it is unloaded from carriers that each hold 132 wafers. In addition, the system identifies and tracks production lot changes. This is one of many stations developed by AEi with this customer for a fully automated production line to manufacture photovoltaic (solar) cells, an industry application where small improvements in yield and performance are critical to success.

AEi’s wafer handling system reduced the carrier loading time by a factor of five by using four different servo-controlled pick and place mechanisms with a total of 12 servo axes and machine vision to determine the exact location of the wafers before handling. Machine vision also inspects each wafer for edge defects (cracks, chips, etc.), dimensional defects, and geometric defects.

The wafer handling system feeds other systems that AEI has helped the customer develop:

• Automated vision-guided laser cutting of pre-wafer silicon ribbons
• Picking wafers and placing them into buffer storage bins
• Testing and classification of wafers based on electrical characteristics
• Alignment of wafers for soldering operations
• Picking wafers from moving conveyor belt
• Placing wafers on moving conveyor belt in configurable patterns