GCA Tropel Ultrasort II

The UltraSort II family of systems is comprised of modular measurement and handling options. The primary measuring instrument is either a FlatMaster (FM) Grazing Incidence Interferometer or the Multi Surface Profile (MSP) frequency-stepping interferometer. The Class 100 systems are Fully-Automated robotic based multi cassette systems. Secondary measurement modules are also available. 

Fully-Automated UltraSort II systems provide cassette-to-cassette wafer handling with user configurable sorting capability. The UltraSort II system can be configured to measure wafer sizes from 2 through 6 inches or optionally 4 through 8 inches in diameter and measure a variety of different wafer materials, including gallium arsenide, sapphire quartz, germanium, and silicon. 

The robot end effector is a vacuum double paddle type and handles wafers from 2 through 6 inches or optionally 4 through 8 inches. The paddle material is anodized aluminum; the paddle surface areas, which contact the wafer, are Teflon coated. The hard coat anodized vacuum chuck used to hold the wafer during the measurement is universal and holds 2 through 8 inch wafers. Standard configuration is 2 – 5 flatted and 6-8 notched. 2-6 flatted with 8 inch notched are also available. 

Each cassette station is configurable as input or output. After placing the wafer cassettes at each station, the operator initiates automatic measurement of all wafers in the input cassettes by starting the measurement process at the computer workstation. A scanner is integrated in the end effector of the robot. The scanner allows the robot to determine the location and number of wafers within the cassettes. 

Each wafer is loaded onto a Prealigner prior to the measurement. The Prealigner holds the wafer with small Teflon coated vacuum chuck. After alignment, the wafer is placed on the measurement vacuum chuck. The precision chuck has been designed for maximum flatness and low contamination. The chuck assembly includes precision actuators to level the chuck and to maintain accurate wafer position during each measurement. After the wafer measurement is complete, the wafer is moved to the appropriate output cassette. 

A manually operated linear stage moves the vacuum chuck to an accessible location for easy chuck removal and replacement. The chuck load position is also used to load the calibration samples. The granite table provides a stable platform for the measurement system. The table also incorporates vibration isolation to provide improved measurement integrity. 

The UltraSort II system uses Corning TMCM and TMS. These software packages are windows graphical user interfaces that run on the Windows operating system. TMS is for customer defined part measurement recipes, part tolerances and display preferences are readily stored in non-volatile memory for dependable and efficient operation. Standard measurement datum include: front referenced, back referenced, clamped, unclamped, and local site. Standard parameters include: Flatness, Bow and Parallelism. Circumferential, X, Y, and Radial Slice information is also available. Customer specific settings for measurement and display parameters may be stored and retrieved which speed and simplify analysis of various types of customer wafers. Measurement results can be exported to other computer systems via RS-232 or over Ethernet connections.