Dear All,

I am facing some some problems regarding the etching of nichrome, sputtered over
SiO2 wafers and PDMS coated wafers. I am using H2O2: HCl:H2O :: 1:3:2 ratio
as the etchant for the nichrome. Ideally, nichrome should get etched away from
the samples in the unpatterned areas. However, sometimes it does so and
sometimes there is no etching even after immersing in the etchant for a long
duration. Even if I use a new etchant solution the problem still persists. I
noticed this for both PDMS coated as well as SiO2 coated samples. Is there
anything that probably initiates the etching in some samples / or is
passivating  my other samples? I even dried the un-etched samples and heated
them  and tried to etch once again. However neither of them etched, whereas
this etchant works perfectly fine sometimes. I shall be highly obliged if
anyone can kindly help me out with problem.

Looking forward to your help.

Thanks in advance

Debashis Maji,
IIT Kharagpur, India - 721302