Production from week 5.5.2008
Last week’s production yielded two wafers (502 & 504) with defect-free membranes. 506 had a high pinhole density. These wafers have a TEOS mask and were annealed twice; the first anneals did not produce pores so they were annealed again at 1000 C.
From these results, it seems that the first anneal “seeds” pore formation and the second high temperature anneal is what opens the voids. The average pore size also shifts with temperature, as illustrated by the histogram shape. The 800 C wafer has only a few mid and large-sized pores. At 850 C, the number of larger pores increases while the medium sized pores stay relatively sparse. At 875 C, the mid-sized pores become more numerous.
Seems like this should be a reasonable size regime for some bio-separation work.
Can someone please pressure test 1 or 2 from each wafer so we know if they could be used for SepCon work, or just diffusion?
Sure thing, I plan on testing them tomorrow.