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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Process optimization<br />
• VCE predicts bottom CD <strong>variation</strong> through the<br />
entire chip for different process recipes<br />
� Two cases characterized <strong>by</strong> the identical <strong>etch</strong> process recipes<br />
are considered. The only difference between these two cases is<br />
that some amount of CHF3 was added to the <strong>in</strong>let gas flow <strong>in</strong> the<br />
Case 2.<br />
� Addition of CHF3 dramatically reduces the fluor<strong>in</strong>e atom<br />
concentration <strong>in</strong> the plasma bulk.<br />
� The later causes an excessive polymer deposition at the <strong>etch</strong>ed<br />
feature sidewalls and bottom that results <strong>in</strong> a bigger <strong>etch</strong> CD bias.<br />
Copyright ©2008, Mentor Graphics.<br />
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