Subject: Re: Etching Chrome

From: [email-masked] (Eric Perozziello)
Date: Tue, 29 Mar 94 02:25:03 GMT

John A Wright <[email-masked]> writes:

J> I am having trouble etching chrome from some glass substrates
J> that I have and am wondering if anyone out there can help me
J> with my problem.

J> The chrome is deposited in a thermal evaporation process and is
J> on the order of 100 angstroms thick.  On top of this, I deposit
J> about 1000angstroms of copper.  The chrome is used as an
J> adhesive layer between the glass and the copper.

J> I have tried several ways to etch throught the Cr/Cu layer but
J> with limited success.  I can easily remove the Cu (with Acetic
J> acid) but the Crome won't come off.  I am trying to etch it with
J> diluted HCl.  When I have just Cr, the HCl works fine but when I
J> add the Cu layer, it no longer etches the Cr.

>From one of the Electrochemical Society's etching rags:

Metals Table

Metal:    |    Etched using:          |    Resistant to:
-------------------------------------------------------------------
.....

Chromium  |   Most strong acids       |  Air, water, weak acids      
          |   (limited use w/         |  most inorganic salts,
          |   acetic,sulfuric         |  most alkalies, ammonia
          |   nitric, and phosphoric) |
          |   most chlorides          |
.....

-------------------------------------------------------------------

How strong is that HCl ??

-Eric

-- 
Al Gore: "President Clinton is running this country in a way that it 
          hasn't been run in a long time."
Me:      "Yeah, since Nixon." 
                Whitewater can be dangerous. Ask Vince Foster.