Hi,

The problem of lift-off is usually related to the pattern profile. It is
recommended to have the pattern slightly undercut. It is also
recommended to use e-beam evaporation for metal deposition technique
rather than the sputtering. This is because of the directionality of the
incoming metal towards the pattern. In sputtering, the step coverage is
'too good' so there is no way the acetone can infiltrate the pattern.

Hope that helps,
Lando

On 5/23/2011 20:31, 崔林 wrote:
> Hi,
>
>       I am using the e-beam to pattern my sample,
> the resulotion is not very high, just around 500nm, and my
> sample is 10nm aluminum on sapphire.
>
>      It is followed by sputtering 100nm metal aluminum.
>      After that, I use the aceton to do the lift-off.
>
>      My problem is that the metal did not peel off as expected. I
> appreciate any advice.
>
>      Thank you!