At that dose, I get cracks and my smallest feature sizes (15 to 25um wide
straight rectangular channel) are seen with a whitish spectrum unde a
microscope along with cracks.
 I thinkk I place the mask correctly. thanks
-Ab


On 3/31/07, Gareth Jenkins  wrote:
>
> Are your sure the print of your mask pattern is facing the wafer? If not
> this will introduce a gap the thickness of the mylar film which is
> enough to affect it.
> I have also just noticed your exposure dose of 700mJ/cm^2 is rather high
> for a 25um film. About 200mJ/cm^2 is recommended (more if you are using
> a filter).