MX 301-AZ
Automatic Thickness Measurement System

This gauge is used to measure the center thickness of 75mm, 100mm, 150mm and 200mm silicon wafers.
Specifications
Resolution
Noise
Precision (Repeatability)
Overall Accuracy

10 nm
3 mm
± 50nm (2)
± 0.25 µm *
*within a temperature range of ±5 K and a thickness range of ± 100 µm no recalibration or of the system is required !
Under control of a computer or an automation system connected to the MX 301-AZ by means of a serial interface, a robot hand takes single wafers out of any slot of a standard wafer carrier, feeds them into the measuring gauge, and puts them back into the same slot after the measurement. The system can be set up to measure all wafers available in a carrier, or to pick a freely selectable subset of wafers out of it. In this case, the host must transmit the type of wafer carrier in use, and before every measurement, the number of the carrier slot to be addressed.

The system offers three modes of operation:

  1. Automatic measuring of wafers in the carrier.
    The system automatically processes a list of wafers (i.e. carrier slot numbers) it has received from the connected host prior to the measurement via the serial interface. It returns thickness values and status information.
  2. Stand alone mode
    If no computer is connected and an operator puts a wafer carrier onto the carrier platform, the system will measure the wafer in the bottommost carrier slot. Pressing a button triggers the measurement, the thickness value appears on a display at the front panel.
  3. Zero offset adjustment of the gauge
    If the button is pressed for a longer period of time, measurements are repeated and displayed continuously. In this case, a key lockable potentiometer behind the front panel allows for zero offset adjustment of the gauge. This feature allows for a metrological link of this system by means of reference wafers calibrated on other systems.

SPC (statistical process control) software is available for the evaluation of the sampled data.

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