A new Three-Dimensional (3D) laser micromachining method
of 3D flexible structures has been introduced to enhance the current mi-
cromachining technology. The machining is carried out with a simple
Two-Dimensional (2D) movement of the laser beam on the work piece.
This method can be applied for machining 3D geometries or bending edges
in various materials. The purpose is to extract the material by an ablation
of matter in order to achieve “V” shape for multi-bend structure. The
process is well controlled and only selective polyimide material removing
on bending edges was used. Two-layered polyimide-copper assembly was
considered. This is a practical case for multilayer structures such as lay-
ered composites and coatings. The mechanical bending analysis of the
system with residual stress was carried out with COMSOL Multiphysics.
Variations in strain and stress of the structure are demonstrated. Dy-
namic bending features were also measured and compared to a non laser
cut and bended substrate. Its mechanical reliability is improved.
Key words: micro-machining, 3D package, laser processing, laser abla-
tion of polyimide, mechanical structures in polyimide, reliability test.