Dear Seh-Won:

Bottom Anti-Reflective Coatings (BARC's) can be used with interference
lithography to produce 200nm pitch gratings.  I would suggest using Brewer
Science ARC® i-CON-7 with either Shipley Ultra i-123 photoresist or another
high resolution i-line resist from ARCH or JSR.  The i-CON-7 has demonstrated
200nm pitch gratings at 351nm exposure wavelength on fused silica and silicon
substrates.  The Shipley SPR-508A may not be a high enough resolution resist
to accomplish these feature sizes.  I would suggest not using any dyed
resists with a BARC since the resulting resist profiles will be sloped.  If the
substrate is planar the thinner BARC would probably be the best.  The thinner
BARC will reduce the amount of resist loss when the BARC is etched as
compared to a thick BARC.

If you have any questions, please contact Earnie Murphy at Brewer Science.  He
can be reached by phone at 573 364-0300 or email at [email protected]

Best regards,

Mac Daily



Subject: [mems-talk] Photoresist for Laser Interference Lithography
> Date: Fri, 21 Mar 2003 15:26:25 +0900
> From: "Seh-Won Ahn" 
> Reply-To: General MEMS discussion 
> To: 
>
> Dear Colleagues,
>
> I have some questions on LIL (Laser Interference Lithography).
> I am doing conventional LIL to achieve 200 nm pitch grating.
> Could you tell me what kind of photoresist is best for this process?
> Wavelength of the laser is 325 nm.
> I am using SPR-508A from Shipley.
> However, it is difficult to achieve good PR profile.
> In addition, will ARC coating under PR be helpful for 200 nm pitch LIL?
> Thank you in advance.
>
> Sincerely,
> Seh-Won
>
>