Finite element simulation of microstructure demolding as part of the LIGA process

In this paper demolding of microstructures as a step in the LIGA process is investigated by means of the ABAQUS Finite Element code. Mechanisms which can lead to failure during demolding are studied in terms of geometry and material properties of the components.

It is shown that failure is expected to occur at the transition from the microstructure to the residual layer. The intensity of loading in this region depends on the thickness of the residual layer and the combination of the polymer (mold material) with the substrate.

An essential result is that use of a substrate has a negative influence on the demolding process for thick residual layers. For thin residual layers, it turns out that the intensity of the stress in the transition region is influenced by the choice of the substrate as well as by the thickness of the residual layer.