Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 2M

It is used as a protective masking layer for the etching of deep structures and can also be used as a template for the electroplating of metal microstructures.

Coating of thick resist is achieved either by multiple spin- coating applications or by spinning special viscous resist solutions at slower speeds (up to 100µm).

With increasing resist thickness, maintaining thickness control and uniformity becomes difficult.

Exposing resist thicker than 5µm degrades the minimum resolvable features size due to limit depth of focus of the expose tool.

The maximum aspect ratio (ratio of resist thickness to minimum features dimension) is approximate 3. i.e. minimum achievable feature size is larger than one third of the resist thickness.