EWG General Description:

EWG (Eccentricity & Wobble Gauge) is a wafer with one XY accelerometer positioned at the center of the wafer and  Z accelerometers positioned at 6 points close to the edge of the wafer. The EWG is measuring the eccentricity & the wobbling of  wafers on spinning chucks in situ. This is the only insitu method of making this measurement. The common method currently used for checking these parameters involves the time consuming process of opening the tool chamber and using mechanical gauges. The new SmartWafer method avoids any tool opening, can be fully automated and is compatible with the InnerSense Docking Station.

EWG Specifications:

      Sensor Thickness:  4.2 mm above a standard silicon wafer (total of 4.9mm)
      Wobble:  (angle between the wafer & the rotation axis) :
        ·  Accuracy:  ± 0.0250 (equal to ± 0.06 mm elevation of the wafer's edge)
        ·  Repeatability: ± 0.010 (equal to ± 0.02 mm elevation of the wafer's edge)
        ·  Rotation speed: 600 RPM
      Eccentricity:  (distance between the wafer center & the chuck’s rotation center):
        ·  Accuracy:  ± 0.03 mm

        ·  Repeatability: ± 0.01 mm

        ·  Rotation speed:  1000 RPM

EWG (Eccentricity & Wobble Gauge)


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