AFM
I got back on the AFM today to rescan the wafers from yesterday and too scan a wafer that Dave had given me a few weeks ago. The 2 panels are from the height channel, I used the 240 tip (yesterday I used the 160 tip). The top panel is the wafer from Dave and the bottom panel is the 1run megasonics @ 225W. Looks pretty different.
The caveat is that I still can’t get these images in repulsive mode. I tried to image pnc-Si today, also. The first time I was in repulsive mode and could see the pores like in the images from our training. After I captured the wafer images above, I could not scan the pnc-Si in repulsive mode anymore. In attractive mode with pnc-Si, I couldn’t see pores, rather, the surface looked somewhat similar to the top panel here. So, I think that you get fairly different images depending on the mode in which you image. The only comforting thing is that the 2 panels above were taken back to back and in attractive mode. I’m talking to Asylum about this issue today.
Yeah, these images clearly show the particles, which is the goal for this particular work. However, operating in attractive mode is not going to work for roughness studies, as it seems to blur out surface features.
Which wafer from Dave is this? Is it a Virginia Semi wafer that has been cleaned, or from another supplier?
If you scan a smaller area, does the situation improve? Have we ordered new tips yet? I wonder if something happened to these ones? Although the image with particles above looks similar to those from yesterday, so maybe the size enhancement is just an effect of the attractive-mode imaging…
Dave, do you remember which wafer this was? I don’t.
I tried scanning a smaller area and the xy particle size stayed about the same, so no help. I think scanning at a slower rate would help though.
I’m ordering new tips today from Asylum.
I forgot to explain the streaks in the bottom image. This is from phase hopping between attractive and repulsive regimes. It doesn’t look pretty, but I was just interested in the presence or absence of particles.
I think this was a wafer straight from the Virginia Semi… no clean.