Modeling the residual shrinkage during lithographic processing on flexible polymer substrates

The challenge of lithographic production of electronic circuitry on polymer foil is that deformations approaching the feature sizes of the circuitry can cause considerable overlay problems and thereby malfunctioning of the devices. The substrate foil is susceptible to several types of deformations. Accurate prediction of these deformations is of great importance, as it will help to improve the production process and thereby improve the quality of the electronic devices. One of the deformations is the residual shrinkage, a deformation that occurs after application of a heat step to a polymer foil. This study presents an experimental investigation of residual shrinkage combined with a modeling approach in which the temperature dependent visco-elastic material properties of the foil are used. The model enables us to more accurately predict overlay errors.