[mems-talk] Difficulties with finding the alignment markings duringthe photolithography on ceramic substrates

[Bob Henderson]

Make you first alignment on a film like nitride or aluminum that will show
thru subsequent layers. Bob Henderson
----- Original Message ----- 
From: "Denis Petrov" <dazeuhl at googlemail.com>
To: <mems-talk at memsnet.org>
Sent: Monday, November 12, 2007 8:08 AM
Subject: [mems-talk] Difficulties with finding the alignment markings
duringthe photolithography on ceramic substrates


Hello,

I have several ceramic wafers to be exposed. While trying to complete
the subsequent photolithography steps, I have encountered the
following problem.
Due to the roughtness of the ceramic surface, it is very difficult to
recognize the alignment marks (or even the structure patterns) in the
microscope... As a consequence, misalignments occure, and that spoils
all the previous work.
Does someone know how to overcome this, or how to enchance the
visibility of the markings?