>
>
> Hi,
>
> Does anyone know of an etchant that will attack my oxide sacrificial
> layer but not the nitride or aluminum.  I have tried straight HF
> and it seems to work quite alright but I am looking for a better
> solution.  It has to be a wet etchant.  Thanks in advance.
>
> Regards
> Yan
>
>
> ________________________________________________________________________
> Yan Loke
> Institute of Microelectronics         e-mail : [email protected]
> Block 85 Science Park Drive           Phone : 870-9433
> The Cavendish #01-02                  Fax : 779-3711
> Singapore 0511
>
>
>
In response to the request for a sacrificial etchant that will not attack alum,
The following are oxide etches which will not attack alum:

Solution #1  NH4F (40%) 4 parts
             HF (49%)   1 part
             Glycerine  2 parts
Solution #2  HNO3 (70%) 1 part
             HF (49%)   5 parts
             Glycerine  10 parts

--
Dr. Kevin M. Walsh
Electrical Engineering Department, Speed Scientific School
University of Louisville, Louisville, KY 40292
(502) 852-0826

Internet address: [email protected]