Patent ID: 8237083

Claim:
A method, for the drilling of holes in a workpiece within a diameter range of 20 μm to 500 μm by means of laser radiation, utilizing on the one hand, the beam quality of laser beam sources as well as, on the other hand, the polarization of said laser radiation, the parameters of the impulses of said laser used, and the type and the pressure of at least one process gas used, said method comprising the steps of: (a) focusing said laser radiation, in particular the ratio of the beam diameter at the site of the focusing element and its focal distance which preferably lies between 1 and 6, and wherein said focusing is done in coordination with a beam quality number K and a wave length λ; and (b) creating a bore hole with the length L whose shape is bottle-like and characterized by a smaller upper diameter d A , an adjacent bottle neck with a length L A with a subsequent widening in a transition area to a diameter d E , and the part that is cylindrical or slightly widening towards the lower end of said bore hole, a fluid entry opening, making up the main volume of said entire bore hole, with a ratio of the diameter of said fluid entry opening to the diameter of a fluid exit opening d E /d A preferably lying in an interval of 1.3 to 2.0, a ratio of the length of said bore hole to the diameter of said fluid exit opening L/d A preferably being 2 to 20, and a ratio of the length of said bore hole to the length of said bottle neck L/L A lying within an interval of 3 to 10.