Hi, all
    I am working on a project which requires to use LPCVD silicon
nitride as KOH etching mask. I wonder if someone can provide some
information about the vendor. The quantity is about 20~25 wafers.
The specification:
    2in wafer,
    240 - 290um thick
    (110),
    N-Phos,
    resistivity 2~5 ohm cm
It's not bare wafer. I doped Boron to some areas of the wafer (about 50
dog-bone shaped 5um X 100um windows) by thermal diffusion. The
estimation concentration is about 10E19 cm^(-3) .Then 80 to 120nm
thermal oxide is grown on the whole wafer. No metals or organic
materials on the wafer.

Is the doped Boron a big problem for the LPCVD process? If so, is there
any way to do LPCVD, say first depositing some PECVD oxide (50 or 100nm)
as a cover layer? Since I am going to do KOH deep etching of Si, I am
not sure if the PECVD cover layer (under LPCVD nitride) is OK with 100um
etching ?

Thanks

Hongtao