Sorter applications provide advanced multiparameter wafer inspection with integrated high speed sorting for quality control of production PV wafers. Owing to wide range automation module portfolio and flexible combined Semilab’s metrology modules, all customer can find perfect configuration what fulfil their production expectations.
Thickness is a primary control parameter of silicon PV wafers. By filtering out wafers with non-standard thickness and shape, waste from wafer/cell breaking can be reduced.
Thickness of PV wafers is measured for two reasons:
WMT/WML uses capacitive probes to measure the distance from wafer surfaces. This way the result is independent on surface quality (reflection).
The capacitance depends on the distance between the probe and the sample:
C = Ɛ . (A/d)
where d is the probe-sample distance. From the measured capacitance the distance can be calculated, and the distances from both sides of the sample makes the thickness determination possible.
Resistivity measurement is based on non-contact Eddy current method
An AC current flows in a coil in close proximity to a conducting material. The magnetic field of the coil induces circulating (Eddy) currents in the sample. The Eddy current measurement is actually the measurement of the electrical loss in the material, which depends on the resistivity. The signal in the sensor is calibrated to samples certified with 4PP.
The tool measures line scans parallel to the belt direction:
Position of the line scans:
WMT/WLT inline tools allow non-contact, preparation free, high-speed thickness and bulk resistivity measurement of crystalline wafers. Robust design and easy integration makes it an obvious choice for wafer sorter applications to sort out of spec wafers. Special design of capacitive probes makes good accuracy even on non-grounded wafers such as in the case of belt transport. Unique design of resistivity sensor makes it independent of grain size variation.
Operating modes and configuration:
PVS-5000 is a high throughput, field proven PV Wafer Inspection and Sorting System.
It combines high reliability wafer handling with Semilab’s industry leading PV metrology, to provide a turnkey solution for sorting of incoming wafers. This is backed by direct expert support from the OEM metrology manufacturer, through our worldwide network of branch offices.
PVS-6000 is a High Speed, field proven PV Wafer Inspection and Sorting System with 5400 wafer per hour throughput. It combines high reliability wafer handling with Semilab’s industry leading PV metrology, to provide a turnkey solution for sorting of incoming wafers. This is backed by direct expert support from the OEM metrology manufacturer, through our worldwide network of branch offices.