Lift Off Process Why Is Evaporation Commonly Used for Coating?

Comparison of step coverage between electron beam evaporation and magnetron sputtering

The step coverage of magnetron sputtering is better.
In electron beam evaporation, the evaporated material is sublimed directly from the source and deposited on the wafer in a straight path, which can avoid the metal covering on the side wall of the mask and only deposit on the surface. Magnetron sputtering may wrap the entire surface and side wall of the photoresist in the deposited material. After the end of the coating, when the photoresist stripping, the stripping solution can not contact the photoresist reaction, resulting in the photoresist stripping is difficult. With electron beam evaporation coating, there is no such problem.

Above is a cross-section of the electron beam evaporation membrane. The degumming solution can react with the photoresist side wall through the gap.

The above is the cross-section of the film layer of magnetron sputtering. It is difficult for the degluing liquid to break through the side wall film layer and react.

What additional processes are needed to use the magnetron sputtering method?
It is necessary to increase the tearing process, tear off the film layer covered by the adhesive surface, so that the photoresist is exposed, so that it is easy to peel.