[Libre-silicon-devel] Status update, nickel etching

David Lanzendörfer david.lanzendoerfer at lanceville.cn
Wed May 22 13:40:03 CEST 2019

Hi all
So today I've prepared three brand new dummy samples with 50nm Nickel and 
exposed metal1 wire structures to the HPR 504 coated onto it.
Then I fed it after 30 minute hard bake to the AST Cirie200 in a pure Argon 
plasma at 30sccm Ar, 500W, 5mTorr.

The only thing etching was the resist, 200nm/10min.

It seems that yesterdays positive initial etching results (oxide became 
partially visible under the microscope) originated from the fact that there 
was still some Cl2 residue on the sample from the previous test with the 
erratic Cl2 MFC.

Because replacing this MFC will take Bao quiet a bit of time, I've decided to 
try wet etching the test samples tomorrow, using a highly diluted standard 
Aluminum etchant which should give me more precision, hopefully enough 
precision, so that I can take the first measurements...

The upside is, that we then already have a formula to get the structures 
etched with wet etching, about which most likely some not so rich labs will be 
very happy.


On Tuesday, 21 May 2019 7:41:35 PM HKT David Lanzendörfer wrote:
> Hi all
> So, because the MFC for the Cl2 has been erratic and the MFC replacement is
> very time consuming and a new MFC is pretty expensive, we just decided to
> manually turn off the Cl2 valve and run it with Argon only.
> Turns out, that ion bombardment was even too slow, when using a pure Argon
> plasma for etching.
> I've spent the entire day working with the Cirie200 today and at the end I
> asked for giving it More Power! *Tim Taylor grunt*
> With 500W instead of 400W I actually had a usable reaction rate and the
> nickel film became so thin, that the underlying oxide became visible.
> Tomorrow I prepare 3 more samples and test the etching with the new recipe.
> I keep you informed
> David
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