That's right and that is happened in final etching stage. When you almost finish etching and proceed it litlle bit more for insurancy. Before that all metal elements still connected with each other and the charge current can easily leak. But in this final stage the sctructure has some floating Metal islands those have connection to gate with thin oxide. Because top of metal is isolated by photoresist the charging current flows through perimeter of these floating area. The less gate capacitance the higher voltage can reach gate voltage. So the ratio of metal island perimeter to gate area is key parameter.the problem here is, during Reactive ion beam/ion beam etching, this structure connected to the gate will gather enough charge to damage the dielectric of gate, ie, thin oxide. so your problem can be reduced by decreasing the area ratio.
analayout said:hi
well antenna means charging of NWELL with respect to gate durinig fabrication
if the nwell to substrate leakage current is high enough compared to gate leakage it will destroy gate
the solution is make nwell to substrate leakage less than gate leakage
for this generally the nwell is tied down to sustrate using m1 that means we r creating a reverse biased diode
regards
analayout
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