We need to design a mask layer on the front side of the wafer assuming that the backside is protected. There should be a repeating pattern of 100 m square openings on the backside of a 500 m <100> Si wafer. Given that we are using 42% KOH for etching and the spacing between the openings on the front side of the wafer should be 10 m:

a) what will the spacing be between the 100 m square openings on the backside of the wafer?

b) how wide are the openings on the front side of the wafer?

Draw the wafer crosssection showing the two openings and label the dimensions. (Drawing doesnt need to be in scale, but it must be dimensioned.)