PV >Products >WMT Series


WMT Series In-Line Resistivity/Thickness Tester (on-the-fly)

Thickness and resistivity are primary quality control parameters for silicon wafers in PV applications. The WMT models, WMT-1 & -3, Thickness and Resistivity Testers allow measurement of wafers “on the fly”, i.e., conveyor belt does not stop during measurement. Therefore, they have the high throughput that meets the requirements of in-line quality control in fully automated wafer production lines.
IN-LINE APPLICATION:
• Incoming wafer inspection and sorting


CONFIGURATION OF A SYSTEM:
• WMT measurement module (incl. 1 resistivity and 1-3 thickness measurement heads)
• Industrial PC (Windows® operation system) and peripherals
• Interface (hardware and software) to automation
SYSTEM SPECIFICATIONS:
sample size:
 100 to 210mm
measurement position:
 adjustable
distance between top and bottom sensors:
 4mm
sample support:
 on belt
wafer vertical position tolerance:
 <300µm peak to peak, including vibration
system dimensions:
 135x460x403mm (WxHxD)
Number of measurement points (for 1 head): 25 points on a 156x156mm wafer in case of 250mm/s belt speed
Resistivity:
measurement technique: eddy current
range: 0.3-15Ωcm
accuracy: 5%
repeatability: 2%
measurement spot size: 10mm
Thickness:
measurement technique: capacitive gauging
range: 100µm - 1.5mm
accuracy: 1% or ±5µm
repeatability: 0.5%
measurement spot size: 10mm
Additional configurations available if needed