We're starting to make new cantilevers this week. Here is our process, largely drawn from Zach's thesis, based on the process from the Chao group (D1200849) and the standard techniques of hard mask etching.
Zach started with a 100 mm (4") undoped <100> Si wafer with 500 um thickness. He reports achieving similar mechanical Qs of the final cantilevers when starting with either SSP or DSP polished wafers, though we may want to investigate this further. To avoid spoiling too many large wafers, I'd like to start by processing our 2" x 280 um wafers that are leftover from the cryo Q experiment, and will inventory our larger wafers to determine what we should order. We also have some 3" wafers we can use to fabricate full-length (7 cm) cantilevers in smaller batches than had we used 4" wafer.
Zach's procedure calls for thinning the central region of the cantilever, which softens the suspension and improves isolation. I expect we'll want to evaluate our cantilevers before thinning, since the procedure to thin the central region is a bit tricky. When we do thin the cantilevers, we will not terminate the process at step 6 but instead continue with the following:
Materials we need to acquire are in bold
Our training status on the equipment is green for 'full user,' orange for 'supervised user,' or red for 'need initial training.