You can use a FIB (Focused Ion Beam system) to do this.
-----Original Message-----
From: Jochen Hetzler 
To: [email protected] 
Date: Sunday, May 17, 1998 7:09 PM
Subject: Etching of Al films


>Hello
>-----
>I'm interested in nanostructuring of 75 nm thick AL (aluminium) films. I
>only know some good etch solutions for Cr, who knows some for Al. I prefere
>Al because of his higher optical thickness.
>
>Thanks
>    Jochen
>
>
>