• Contactless measurements with capacitive sensors
  
• Resolution 0.1 micrometers
  
• Mathematical vacuum chuck simulation
  
• Maximum measuring time per wafer: 5 Seconds
  
• No moving parts during the measurement
  
• RS-232 Serial interface
  
• Evaluation and data base program for PCs included
  
• Quick and easy recalibration, large thickness range
  
• Optional software for stress evaluation or data export
  

Description

The MX 203 is a compact desktop instrument for geometry measurement of silicon wafers. The gauge is based on two heavy steel plates mounted opposite each other. Each plate contains a set of contactless capacitive sensors, which are arranged in a star-shaped pattern. The wafer is inserted into the air gap between the two plates, then positioned on three resting pins for the measurement. The sensors measure the distance to the wafer surface, and the results are then sent to the connected PC via the serial interface. Based on these distance values, and the supplied PC software computes the following wafer characteristics:

• Thickness related: Center-, Average-, Min.-, Max.- and Local Thickness, TTV
  
• Flatness related: Local FPD, max. neg. FPD, max. pos. FPD, TIR
  
• Warp related: Local Warp, Total Warp, Bow, Shape, SORI