Use Pad Etch IV from Ashland Specialty Chemical.
It has NH4F + CH3COOH + H2O, which generates some HF for oxide etching,
plus propylene glycol to inhibit attack of the aluminum.
        --Kirt Williams Agilent Technologies


> -----Original Message-----
> From: Ravi Shankar [mailto:shankar@sclchd.co.in]
> Sent: Tuesday, December 25, 2001 10:54 PM
> To: mems-talk@memsnet.org
> Subject: [mems-talk] etch psg oxide with Al
>
>
> Hi
> i want to etch psg oxide without affecting aluminium, could
> anybody give
> me some reference regarding it. in fact i found out from
> somewhere that
> ammonium fluride and acitic acid is good, but could not get
> any further
> info on its concentration, temperature and working mechanism.
> regds
> ravi shankar
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