| General | Compact Modeling |
Process Technology
Question 011-07: What is the good surface passivation process on the Ge (SiGe) substrate?
Answer 011-07: The answer to this question appears to fall in the proprietary domain and experts approached so far are reluctant to answer it. Hence, we are unable to provide an answer to this question at this time. If any of the readers have a possible lead, please send your response to samar@ieee.org. [back to top]
Question 010-07: “I'm embedding chips (processed CMOS, 0.5 ... 2 mm on each side) into PMMA slides with appropriately sized recesses. Can you recommend a leveling agent to planarize the surface after embedding (e.g. for subsequent metallization).”
Answer 010-07: The answer to this question is of proprietary nature and the experts contacted provided only the following note: “The leveling agent before metallization is generally sulfuric acid system, for example, H2SO4+H2O2, NaHSO4, H2SO4, Na2S2O8 etc." If any of the readers have a possible lead to a more detailed answer to this question please send a response to samar@ieee.org. [back to top]
Question 004-07: I am trying to fabricate a PDMS microchannel over glass/silicon dioxide/alumina-stacked waveguide surface. I am facing problems in spin coating PDMS and then later patterning it for a dry plasma etching? Please tell me what is the best procedure to pattern and etch PDMS without any harm to the alumina surface?
Answer 004-07: The only way you can do this is by an atomic layer deposition (ALD) process and not by spin coating. You need about 200 – 500 nm of thickness and it is only possible by ALD. ALD film ensures coverage on all sides of a released MEMS device and is done at a relatively low temperature (down to 150°C). The ALD film thickness can be precisely controlled as each reaction cycle deposits approximately one monolayer of atoms. Also, the idea of alumina is great for protecting MEMS. [back to top]
