Measuring silicon to 0.0002” Isn’t For Amateurs

Consider the task of measuring silicon wafers, the physical heart of computers and high-tech equipment: it’s a critical task for IC companies and wafer makers and requires extraordinary precision.

KLA-Tencor, a multi-national corporation with whom GMT has had a successful association for 10 years, builds machines which measure wafer geometry parameters, such as thickness, shape and flatness.
WaferSight 2 is a KLA dual-sided interferometer, which measures nanotopography and edge of wafer roll-off metrology. GMT pallets carry 12-inch diameter silicon wafers through this machine’s scanning process.

Any vibration of or distortion in these pallets would render the measurements useless. Only a pallet made from aerospace-grade high-modulus carbon is up to this challenge. They’re light enough to permit rapid acceleration, which allows higher production rates. They are stiff enough, so there’s no deflection when loaded. This stiffness, combined with lighter weight than aluminum or steel, eliminates jitter and vibration to maintain accuracy.

GMT developed the specific ply-orientation, which determines the angle for each of more than 120 plies of carbon laid down for the structure, and the machining procedures which finish each pallet part. In places, we hold tolerances to within 0.0002” – which is 20-times smaller than the thickness of a hair on your head.

Those with a truly scientific interest can find out more at and click here for more about GMT robotic and machine parts.