Sample Requirements and Preparation
Note that thick films requiring high etch rates (and hence high amounts of heating), so this may mean one needs to load the sample directly on the chuck by venting the chamber (instead of using load lock). This will permit users to apply more torque and get better cooling of the chuck. However, it requires special training.
For EPD, note that argon atomic mass is the same as MgO, so the EPD is not able to sense (ionized) MgO in the large Ar ion background.
We provide 15x15mm and 20x20mm cutouts in 6" Si + oxide wafers (0.67mm thick) at the AJA for general use. Samples should be smaller than these cutouts.
Some users may wish to cut their own wafer due to size constraints. Neil Dilley and Nick Glassmaker have used the LasX fiber laser in the BNC 1100A lab successfully on Si wafers. Please inquire with Nick ( nglassma@purdue.edu ) if you are interested in having a wafer cut.
- artwork: file = Siwafer_cut_fasterspeed ; 20x20mm square with 1mm radiused corners, "X" cut in middle to allow material to break out easier.
- material: 6" (actually 150mm) diameter x 0.67mm thick Si wafer with oxide from BNC store room
- cut on the BACK (unpolished) side of the wafer
- laser power = 100 %
- depth control = off
- Repeat = 150
- speed = 200 mm/s
After cutting (it just takes a few minutes), put the sample face down on a hollow cylinder support and gently press on the cracks until the pieces fall out. Careful, the wafer can break if pressed too hard!
A much faster laser speed (200 mm/sec) + more repeats (800?) might be a better method, since we see some evidence of hotspots and melting Si at the end of our cut, and we would prefer to ablate the material instead of melting it.
