You can try using HNO3:HCl and diluted HF for Pt and Ti, separately.
Before etching Pt, a Ti pattern should be made on the Pt.

Yours sincerely,

Huaping XU
=======================================

At 12:51 PM 4/3/99 +0800, you wrote:
> Dear All,
> I am urgently looking for an effect method (preferly wet) to etch electrode
> platinum (Pt) on silicon substrate with a thin layer of Ti. Would you please
> give me help?
> Best regards.
>
> ________________________________________________________________
> Dr Kong Lingbing
> School of EEE
> Nanyang Technological University
> Block S1, Nanyang Avenue
> Singapore 639798
>
> Tel: (65) 7906084
> Fax: (65) 7933318
> Email: elbkong@ntu.edu.sg
> ________________________________________________________________
>
>
====================================================================
Huaping (W-ping) XU, Ph.D.
Postdoctoral Fellow of Japan Society for the Promotion of Science
Super-Eye Image Sensor Project
Osaka Prefecture Technological Research Institute
2-7-1 Ayumino, Izumi-shi
Osaka 594-1157
JAPAN
Tel: ++81-725-512534(O) Fax: ++81-725-530423(O)
E-mail: xu@seis.tri.pref.osaka.jp
        xu@semi.ee.es.osaka-u.ac.jp
Tel/Fax: ++81-725-443816(H)
Home address:
Rm.202, 6-14-14 Fuchuo-machi
Izumi, Osaka 594-0071
JAPAN