Pinhole study
Last week, five wafers were produced – three had a double 3500 A wet oxide growth/strip and two had a single 3500 A wet oxide growth/strip. From Jess’ AFM work, an as-is wafer showed a high density of 5-7 nm particles on the wafer surface. With a double oxide growth/strip, these particles do not show up on the AFM. The goal of this experiment was to show if a double growth/strip reduced pinhole density. I found that there was little difference in defect density between the double vs. single growth/strip.
I did notice that there was a higher pinhole density over the bulk as I looked towards the outer portion of the wafer. The pinholes were confined to the membrane area in the center of the wafer.
Discussion of “why” presented at NRG meeting…