Problem 2.1 On a (100) silicon (

400\\\\mu m

thick) wafer,

3000-\\\\angstrom \\\\angstrom

-thick

SiO_(2)

has been thermally grown and patterned for a 250-\

\\\\mu

-diameter circle on both sides of the wafer (the circular area is where the

SiO_(2)

is removed, and the circle on the front side\ is aligned with that on the backside). If the wafer is etched in EPW for (a) 1 hour, (b) 4 hours, and (c) 12 hours, what will be\ the resulting structures? Draw the top views and cross-sectional views for (a), (b), and (c). Assume that the EPW etches\ (100) silicon planes at

1\\\\mu (m)/(m)in

, while it etches the (111) planes 35 times slower (i.e.,

(1)/(35)\\\\mu (m)/(m)in

).

Problem 2.1 On a (100) silicon ( 400m thick) wafer, 3000A-thick SiO2 has been thermally grown and patterned for a 250 m-diameter circle on both sides of the wafer (the circular area is where the SiO2 is removed, and the circle on the front side is aligned with that on the backside). If the wafer is etched in EPW for (a) 1 hour, (b) 4 hours, and (c) 12 hours, what will be the resulting structures? Draw the top views and cross-sectional views for (a), (b), and (c). Assume that the EPW etches (100) silicon planes at 1m/min, while it etches the (111) planes 35 times slower (i.e., 351m/min ). Problem 2.1 On a (100) silicon ( 400m thick) wafer, 3000A-thick SiO2 has been thermally grown and patterned for a 250 m-diameter circle on both sides of the wafer (the circular area is where the SiO2 is removed, and the circle on the front side is aligned with that on the backside). If the wafer is etched in EPW for (a) 1 hour, (b) 4 hours, and (c) 12 hours, what will be the resulting structures? Draw the top views and cross-sectional views for (a), (b), and (c). Assume that the EPW etches (100) silicon planes at 1m/min, while it etches the (111) planes 35 times slower (i.e., 351m/min )