Are all the sides angled? That is, do you have pillars that appear to
be cones with the tops cut off?

Did you set the polarisations of the three incident beams properly?
You'll need to ensure that you're including this in your calculations:
orthogonal polarisations don't interfere.

Are the beam paths the same length? This is important with short pulsed
laser exposures. You can end up with your beams arriving at different
times.

What is the exposure vs solubility profile of the resist like? Is there
a sharp change between soluble and insoluble?

Hope this helps,

Chris Blanford

On Monday, May 3, 2004, at 06:56  am, [email protected] wrote:

> Dear Sir
> I do IL with 325nm HeCd laser
> The structure of sample we use is PR/SiN(400nm)/ARC/Si
> PR --> TOK THMR-iN, or Shipley Ulra-i 123
> ARC--> Brewer Science XHRiC
> Our target is 2D lattice pillars or holds (period 350 nm,diameter
> 100nm)
> Afrer exposed and developed, The photoresist profile is not that good
> The most important problem, side wall is tilted at an angle.
> I would like to know if there is any solution?
> Any batter photoresist or trick?
> Thank you
>
> Best Regard
--
Christopher F. Blanford
Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
Phone: +44 (0)1865 282603; Fax: +44 (0)1865 272690
PGP keyID: 8D830BC9  http://pgp.mit.edu/