Patent ID: 6979648

Claim:
A method for determining anti-reflective coating over-etch time to achieve a final critical dimension (CD final ), comprising: providing a plurality of semiconductor wafers with each of said plurality of wafers, comprising: a first layer over a semiconductor, an anti-reflective coating layer over said first layer, a patterned photoresist layer over said anti-reflective coating layer wherein said patterned photoresist layer has a first pattern comprising a resist critical dimension (CD resist ); selecting a first wafer from said plurality of semiconductor wafers; determining a first over-etch time (t*); pattern said anti-reflective coating layer using said first over-etch time; using said patterned anti-reflective coating layer, pattern said first layer and measure a critical dimension (CD′ final ) for said first wafer; determine a second over-etch time (t lot ); and using said second over-etch time (t lot ), determine an anti-reflective coating over-etch time t(x) for each of said plurality of wafers, wherein t(x) is an anti-reflective coating over-etch time for a wafer x in said plurality of wafers.