Design specific variation in pattern transfer by via/contact etch ...
Design specific variation in pattern transfer by via/contact etch ...
Design specific variation in pattern transfer by via/contact etch ...
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Effects of Aspect Ratio & Microload<strong>in</strong>g<br />
Etch rate <strong>variation</strong> across layout caused<br />
<strong>by</strong>:<br />
� Across-layout <strong>variation</strong> <strong>in</strong> concentration<br />
of neutrals <strong>in</strong> the above-wafer plasma<br />
region - Microload<strong>in</strong>g<br />
� Variation <strong>in</strong> resistance to the <strong>in</strong>terfeature<br />
transport of neutrals - AR<br />
� Variation <strong>in</strong> plasma visibility - AR<br />
Neutrals concentration<br />
across layout<br />
Variation of solid angle of<br />
visibility<br />
Ω Ω<br />
Proc. of SPIE Vol.<br />
6520 65204D-1<br />
� AR <strong>variation</strong>s are responsible for the distortion<br />
<strong>in</strong> <strong>etch</strong> rate, sidewall slope and <strong>etch</strong> depth<br />
developed <strong>in</strong> neighbor<strong>in</strong>g features<br />
� Microload<strong>in</strong>g is responsible for those<br />
distortions developed <strong>in</strong> the identical features<br />
located <strong>in</strong> different neighborhoods<br />
characterized <strong>by</strong> different <strong>pattern</strong> densities<br />
Layout and averaged patter density<br />
Copyright ©2008, Mentor Graphics.<br />
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