Jeffrey,
The biggest result of accidentally using the same dose in i-line that
you had been using in broadband is that you are most likely
underexposing with i-line.
Most broadband systems do not integrate the exposure intensity across
the full exposure band (typically 350 - 450 nm, encompassing g-, h- and
i-line). Instead, the intensity will be measured centered around a
single band, with some bandwidth of sensitivity. For instance, it is
common with a broadband system to measure the intensity at i-line - this
is valid for dose control, because the remainder of the exposure bands
is proportional.
In my experience, using EVG620 and EVG6200 systems, which are measured
at i-line, the full exposure intensity of all bands is ~3x that of the
i-line reading alone. This means that, for resists that are sensitive
to the full band, if an i-line only dose is recommended in the data
sheet (say, 100mJ/cm2, like for an ~1um layer), I find that my optimal
dose is roughly 1/3 of that (35 mJ/cm2).
Since AZ9260 is broadband sensitive, giving it a dose of 1500mJ/cm2
i-line is most likely providing ~1/2 - 1/3 the dose of a full broadband
exposure.
Best Regards,
Chad Brubaker
EV Group invent * innovate * implement
Senior Process Engineer - Technology - Tel: 480.727.9635, Fax:
480.727.9700 e-mail: [email protected], www.EVGroup.com
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Yue Mun Pun, Jeffrey
Sent: Tuesday, August 07, 2007 7:08 AM
To: [email protected]
Subject: [mems-talk] Using AZ9260 on i-line or broadband (h-line)
Hi,
I have been using AZ9260 for my lift-off processes using broadband
exposure at 1500mJ/cm2. Today I had accidentally switched to the i-line
(365nm) mode at the same energy dose. I have read that wavelength of
light may contribute to difference in sidewall profile. However in my
case, my structures are huge (about 1mm by 600um), so this should not be
of any effect for lift-off.
Can anyone share with me what are other consequences of using i-line
versus h-line for AZ9260?
