process with a quartz substrate n 365 equals 1 474 such that an etch depth of 3850 u00e5 produces a shift of 180 u00b0 for a deep uv process at 248 nm n 248 equals 1 508 such that a 2440 u00e5 quartz etch shifts the light 180 u00b0 substituting these values into equation 5 results in a table can be created to help determine an appropriate value for i 1 and i 2 using the values from equation 8 results in the following table ______________________________________ i sub 1 i sub 2______________________________________ 1 1 5773 3 4 7319 5 7 8865 7 11 0411 9 14 1957 11 17 3503______________________________________ from this table it is apparent that at i 1 equals 5 i 2 is approximately equal to an even integer in this case 7 8865 using a value of 5 for i 1 it is possible to calculate a depth for the phase shifting layer which will produce a 180 u00b0 phase shift for u03bb 1 and an approximately 0 u00b0 phase shift for u03bb 2 using a value of i 2 equals 8 it is possible to obtain a depth which will produce a 0 u00b0 phase shift for u03bb 2 and an approximately 180 u00b0 phase shift for u03bb 1 in order to.