Optical Fiber Module for Efficient Laser Etching of Vias
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
An optical fiber module contains conical optical fibers which concentrate a laser beam to provide an efficient projection system for laser etching of vias in chip packaging materials. Coating the outside of the fibers further reduces the losses due to evanescent modes. Holes (vias) in materials are etched by the focused laser illumination. It facilitates the efficient transfer of the energy in a laser beam to prescribed points in the material where the holes are to be etched. Intense excimer laser radiation can be used to etch polymeric materials in vacuum or air, or metals in a suitable atmosphere containing a halogen gas. It is sometimes necessary to etch small holes (vias) in these materials, either isolated or in non-uniform arrays.