Lift-off (microtechnology)

This is done by etching openings through the layer so that the target material can reach the surface of the substrate in those regions, where the final pattern is to be created.

After the lift-off, the target material remains only in the regions where it had a direct contact with the substrate.

Lift-off is applied in cases where a direct etching of structural material would have undesirable effects on the layer below.

Lift-off is a cheap alternative to etching in a research context, which permits a slower turn-around time.

This can for instance be used to create shapes that will prevent side walls of the resist being covered in the metal deposition stage.

Lift-off process steps: I. Preparation of the substrate
II. Deposition of the sacrificial stencil layer
III. Patterning the sacrificial layer (ex. etching), creating an inverse pattern
IV. Deposition of the target material
V. Washing out the sacrificial layer together with the target material on its surface
VI. Final pattern Layers:
1) Substrate
2) Sacrificial material
3) Target material