Question: A silicon wafer of 100 mm diameter has 1 µm lines fabricated on it. The photomask is made of soda lime glass with a coefficient of thermal expansion (CTE) of 10 ppm (10 × 10-6/?C). How accurately must the temperature in the patterning process be controlled inthe 100 mm wafer below 0.3 µm? Silicon CTE is 2.5 × 10-6/?C.