#homecmos IRC log for Wednesday, 2011-06-29

azonenbergWhich means I have until then to prepare samples00:25
azonenbergI have two more on the to-do list - a die with hardmask lifted off and baked, then etched in KOH (but not stripped, so i can observe undercut)00:25
azonenbergAnd another one gone all the way00:26
azonenbergiow, a full hardmask-liftoff-etch-strip sequence00:26
azonenbergHere goes... gonna try doing a full process on a die soon02:16
azonenberg_labSo I'll be doing this die using the same method I did last night02:33
azonenberg_labExcept that time I stopped pre-etch so i'd have a nice specimen to image02:33
azonenberg_labThis time i'll take it to completion and see...02:33
azonenberg_labWOOT04:37
azonenberg_labI see a pattern on this die...04:38
azonenberg_labGotta etch another minute, then strip04:38
azonenberg_labBut this might be my first (messy but very real) success at the process04:38
azonenberg_labHmm, the hardmask cracked04:52
azonenberg_labwonder whats up with that04:53
azonenberg_labBut the next one looks quite nice05:11
CIA-67homecmos r96 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Today's lab notes05:39
azonenberg_labhttp://i.imgur.com/0PwSX.jpg05:49
azonenberg_labFirst semi-successful KOH etch05:49
azonenbergWell, looks like i still have some stuff to do06:33
azonenbergand no time to do any more processing between now and the SEM session on thursday06:33
azonenbergNext to-do, if the SEM images confirm my theory, is to prepare 10-20 dies, spin coat them all in resist06:33
azonenbergsoft bake, expose them all one at a time (no multi-exposure capability yet), develop them all, and rinse06:33
azonenbergthen one at a time try coating experiments06:34
azonenberglekernel: http://i.imgur.com/0PwSX.jpg16:41
lekernelthat's engraved silicon?16:41
azonenbergNeed to fix a few more issues with the hardmask (it didn't strip completely for some reason) but this is a mostly successful pattern etched down a couple microns with KOH16:41
azonenberginto <100> Si16:41
lekernelhehe, cool!16:42
azonenbergthis is at 100x magnification, the thinnest lines are about 20 um16:42
azonenbergThe process should scale further (to 5um) but i'm doing process development at a larger scale for now16:42
azonenbergAnother few days and hopefully i'll have these bugs ironed out16:43
kristianpauli can barelly read the 20 um in the botton, but, yeah !!16:44
kristianpaul:-)16:44
azonenbergkristianpaul: That was at the edge of the FOV16:44
azonenbergDidnt expose all the way16:44
azonenbergI need a better light source still16:44
azonenbergRough guess the entire cube is 1mm across16:45
azonenbergThis camera isnt calibrated so i cant be too sure16:45
bart416Ok, this is a weird question, I think I'm reading it wrong16:53
bart416Consider the integral expression in x: P = x^3+x^2+ax+1, where a is a rational number. At a = ... the value of P is a rational number for any x which satisfies the equation x^2+2x-2=0, and in this case the value of P is ... .16:53
bart416What the hell are they asking there? :S16:54
azonenbergIntegral as in integer-valued result? Or as in calculus16:54
bart416no clue16:55
azonenbergSince it looks like algebra to me16:55
bart416yeah does so to me as well16:55
bart416But the way the question is asked makes it weird16:55
bart416answers are -4 and -1 btw16:55
bart416azonenberg, so what the hell are they asking there?16:59
bart416Cause I don't get it16:59
bart416Cause what I think they're asking makes no sense at all16:59
azonenbergbart416: no idea, kinda busy atm17:00
azonenbergHmm... so it looks like some of my problems are caused by photoresist contaminating th ehardmask18:04
azonenbergneed to figure out how to remove it18:04
R0b0t1A tiny scrubby brush18:50
azonenbergR0b0t1: Lol18:51
azonenbergSeriously, i'm not sure18:51
azonenbergSomebody suggested an RCA clean before coating, which will help me confirm that it's not due to surface contamination (but i'm 99% sure its not)18:52
azonenbergThat wouldn't solve my real problem18:52
azonenbergWhich is that the photoresist seems to be dissolving into the hardmask18:52
R0b0t1Ouch.18:52
R0b0t1hmmm18:52
azonenbergResulting in a complex that's less resistant to prolonged etches but also difficult to strip :P18:52
azonenberghttp://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-06-29/S7301011.JPG18:52
azonenbergBrown background is PR covered in hardmask before liftoff18:53
azonenbergthe low-lying areas are hardmask on silicon18:53
azonenbergthe brown spots in the middle of those areas are my unknown contaminant or whatever18:53
azonenbergIt looks a lot like photoresist, except there was no resist there earlier18:53
azonenbergSo i think its dissolving into the hardmask, then depositing there as the solvent evaporates18:53
azonenbergThis image is at 400x18:54
azonenbergFOV is around 400um18:54
R0b0t1Is there a  way to change solvent or use much less?18:59
azonenbergR0b0t1: The solvent is in the solution, i got it as a liquid19:01
bart416azonenberg, the entire issue with the question was the At should be a For :P19:11
bart416+ P is a function19:11
azonenbergOh lol19:11
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