143f2010-06-soln - HW#6 Solutions EE143 Fall 2010 Problem 1(i Flux arriving at a wafer distance r F’(cos 2/r 2 Thickness deposited on wafer F’

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HW#6 Solutions EE143, Fall 2010 Problem 1 (i) Flux arriving at a wafer distance r F’ (cos ) 2 /r 2 Thickness deposited on wafer F’ cos ( with = ) (cos ) 3 /r 2 Since cos = (r/2)/R, therefore thickness r . (ii) Step coverage problem is due to directional flux used for deposition ( e.g. both evaporation and sputtering). Even the spherical receiving surface will be making different angles to the wafer surface normal with different r positions, we will still see step coverage effects. The step coverage morphology will vary at different r positions. Problem 2 The corner profiles shown in sketches below are approximate only. The exact shape depends on the initial roundness of the corners. a.) After 1min: b.) After 2min: =500 866 5000 1000 cos 30 =866 1000 cos 60 30 2886 5000 tan 30 = SiO 2 3386 5866 tan 30 = 2000 cos 30 =1732 2000 cos 60 1732 2886 = 6732 tan 30 SiO 2 3886 =1000
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Problem 3 (a) (b) For conformal deposition, less deposition thickness is needed to planarize high aspect ratio ( large height /narrow width) trenches.
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This note was uploaded on 03/03/2012 for the course EECS 142 taught by Professor Ee142 during the Spring '04 term at University of California, Berkeley.

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143f2010-06-soln - HW#6 Solutions EE143 Fall 2010 Problem 1(i Flux arriving at a wafer distance r F’(cos 2/r 2 Thickness deposited on wafer F’

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