6/9 Updates on production
Here’s the latest news from the production front:
We are still struggling with the pinhole issue. Last week, Chris and JP tried a matrix of conditions to try to eliminate the particle contamination. Efforts included using the CO2 snow cleaner and a piranha solution clean. After etching the first wafer which saw only the piranha clean, it appears the density of pinholes is comparable to those etched in weeks past. We now suspect that the sputter target could be the source of contamination.
Chris’ email:
Anyway, if this run does have pinholes, it’s starting to look like these particles are coming from the sputter machine itself or from the uncleaned air immediately before sputtering our films. If pinholes do show up again, next week will be a characterization week instead of a production week, to identify exactly where these particles are coming from. If it is actually the sputtering system, the only two things that have changed recently are 1) the target (it has many cracks in it due to supplier quality or insufficient cooling due to a UR facilities issue) and 2) the high vacuum pump nearing end of life. Both of these items have been researched and orders have been placed.
This week will be spent playing detective to try to identify what these particles are on the SEM/EDX.