| azonenberg_lab | Time to start tonight's experiments | 02:24 |
|---|---|---|
| azonenberg_lab | Step 1: measure etch rate of my film in SC2 | 02:24 |
| azonenberg_lab | 5 seconds its gone | 02:32 |
| azonenberg_lab | lol | 02:32 |
| azonenberg_lab | guess 60 was a bit much... | 02:33 |
| azonenberg_lab | And just ran another test - photoreist over Cu over Ta2O5 | 03:10 |
| azonenberg_lab | Successful patterning of Cu with 5 sec in SC2 | 03:10 |
| azonenberg_lab | Waiting for the hot plate to warm up so i can see how well the Cu + photoresist works as a hardmask for HF | 03:10 |
| azonenberg_lab | Well, metal patterning is now a solved problem :) | 04:09 |
| azonenberg_lab | And no matter how this current experiment turns out its the closest i've ever gotten to reliable Si wet etching | 04:29 |
| azonenberg_lab | its just a matter of tuning layer thicknesses now | 04:29 |
| azonenberg_lab | the process works great | 04:29 |
| CIA-67 | homecmos r105 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Today's lab notes | 05:16 |
| azonenberg_lab | It pretty much worked - the Cu delaminated slightly due to undercut but a thinner oxide layer should fix it | 05:16 |
| azonenberg_lab | Pattern transferred from mask to photoresist reduced 10x, then to evaporated Cu, then to Ta2O5, then to Si | 05:17 |
| azonenberg_lab | Now its just a matter of getting sharper edges, better adhesion, etc | 05:17 |
| azonenberg_lab | Right now i dont feel comfortable calling 20 microns my achievable feature size, 30-40 is more like what i can actually do with the current process | 05:17 |
| azonenberg_lab | my finer features didnt quite resolve | 05:17 |
| azonenberg | http://i.imgur.com/CQk0G.jpg | 05:55 |
| azonenberg | This is the second test die I ran today | 05:55 |
| azonenberg | Features were narrowed due to overetch of the hardmask | 05:56 |
| azonenberg | But overall it was my most successful run to date | 05:56 |
| azonenberg | And shows potential for improvement | 05:56 |
| azonenberg | I want to try some tests on <110> in the next few weeks and try doing through-wafer KOH etches | 05:56 |
| azonenberg | lekernel: Did you see my die shot from last night? | 13:52 |
| azonenberg | Had some slight undercut of the mask but it was largely successful :) | 13:52 |
| bart416 | pictures! | 13:53 |
| azonenberg | Uploading now | 13:53 |
| azonenberg | Slow cable is slow :P | 13:56 |
| azonenberg | I dont have time to select and downsample so i have to do the raw camera-res jpegs | 13:57 |
| azonenberg | A quarter gig of data (my last three lab sessions didnt get uploaded until now) at 1 Mbps or even a bit less... | 13:58 |
| bart416 | Anyway, I'm off for a few hours | 14:05 |
| azonenberg | k | 14:08 |
| kristianpaul | where are the pictures.. | 16:25 |
| kristianpaul | ?¿ | 16:26 |
| azonenberg | Just finished uploading, sec | 16:27 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/ | 16:27 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301536.JPG is 400x of the die copyright halfway through processing | 16:27 |
| azonenberg | The yellow-green is around 200nm of tantalum oxide over silicon | 16:27 |
| azonenberg | red-orange is 200nm of evaporated copper with photoresist over it | 16:28 |
| azonenberg | this is after the first wet etch | 16:28 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301542.JPG is 100x after the second wet etch | 16:28 |
| azonenberg | The oxide layer was too thick ( i need to try 100nm next time) so the HF undercut the maks a little, note the copper/photoresist in the background fell off due to undercut | 16:29 |
| azonenberg | But the oxide is still present over most places it should be (though a little thin) | 16:29 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301547.JPG is 400x after stripping the Cu / PR | 16:29 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301551.JPG is a 40x die overview after the final KOH wet etch and mask strip (so what you're seeing is all Si except for a bit of some brownish precipitate in the lower parts of the etched areas) | 16:31 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301552.JPG is 100x | 16:31 |
| azonenberg | And http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-22/S7301553.JPG is 400x (a bit blurred but you can clearly see the angled sidewalls of the holes since this is <100> Si) | 16:31 |
| kristianpaul | 551 looks a bit messy compared to 536 | 16:37 |
| kristianpaul | but of course, is all Si :-) | 16:37 |
| kristianpaul | this is taking using metallurgical microscope, right? | 16:42 |
| azonenberg | Yes | 16:44 |
| azonenberg | And yes, i am still working on getting better results | 16:45 |
| azonenberg | The problem is that the Ta2O5 was too thick so the HF undercut the Cu hardmask | 16:45 |
| azonenberg | I need to use a thinner oxide layer and maybe a little more Cu | 16:45 |
| azonenberg | But overall it worked surprisingly well | 16:46 |
| kristianpaul | indeed, well if you take look back to previos results of course ! | 16:47 |
| azonenberg | Lol yeah | 16:47 |
| azonenberg | This was the first die i actually took all the way through the process that even sort of worked | 16:47 |
| azonenberg | So now its just a matter of tuning it to give better results | 16:47 |
| azonenberg | I plan to do prep (Ta2O5 + Cu deposition) on a quarter of a <110> wafer in the next week or two | 16:47 |
| azonenberg | so i can try some vertical etches | 16:47 |
| Action: azonenberg wants a comb drive :) | 16:49 | |
| azonenberg | lekernel_: How far do you think i am from a working comb drive now? I have silicon patterning mostly worked out, i can deposit dielectric (Ta2O5 is actually a high-K material), and I can deposit metal if i borrow time on the evaporator | 17:28 |
| azonenberg | Think end of summer to end of the calendar year is feasible? | 17:29 |
| nathan7 | azonenberg: :o | 17:59 |
| azonenberg | nathan7: :o at what? | 18:23 |
| nathan7 | :o at it all | 18:32 |
| kristianpaul | wellcome solrize , check the paper http://colossus.cs.rpi.edu/~azonenberg/papers/litho1.pdf | 18:32 |
| --- Sun Jul 24 2011 | 00:00 | |
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