Laser beam scanning method for forming via holes in polymer materials
AssigneeGeneral Electric Company
InventorsCharles W. Eichelberger, Robert J. Wojnarowski, Kenneth B. Welles, II
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Abstract
The surface of a polymer dielectric layer is scanned repeatedly with a high energy continuous wave laser in a pattern to create via holes of desired size, shape and depth. This is followed by a short plasma etch. The via holes are produced at commercial production rates under direct computer control without use of masks and without damage to conductor material underlying the dielectric layer. A two-step technique usable to form a large hole to a partial depth in the dielectric layer and several smaller diameter holes within the large hole through the remainder of the dielectric layer depth allows formation of a large number of holes in a given area of a thick dielectric layer.
Claims27
A method for producing via holes in a polymer dielectric layer comprising the steps of:
- scanning a predetermined area of the polymer dielectric layer with a laser beam in a predetermined pattern at a sufficient level of energy and speed to heat a small volume of the polymer dielectric to a point of vaporization during a predetermined laser beam dwell time, said volume being the product of the laser beam maximum energy spot area and the depth of a surface layer portion of the polymer dielectric layer;
- and
- repeating said scanning of said area for a sufficient number of times to etch a desired amount of polymer dielectric layer from said predetermined area.
A method for producing via holes in a polymer dielectric layer comprising the steps of:
- scanning a first predetermined area of the polymer dielectric layer with alaser beam in a first predetermined pattern at a sufficient level of energy and speed to heat a small volume of the polymer dielectric to a point of vaporization during a predetermined laser beam dwell duration, said volume being the product of the laser beam maximum energy spot size and the depth of a surface layer portion of the polymer dielectric layer;
- repeating said scanning of said first predetermined pattern for a sufficient number of times to etch a first desired amount of polymer dielectric from said first predetermined area;
- scanning a second predetermined area of the polymer dielectric layer with said laser beam in a second predetermined pattern at said level of energy and speed to heat another said small volume of the polymer dielectric to a point of vaporization during said predetermined laser beam dwell duration, said second predetermined area being entirely within said first predetermined area;
- and
- repeating said scanning of said second predetermined pattern for a sufficient number of times to etch a second desired amount of polymer dielectric from said second predetermined area.
Dependencies are inferred from the claim text.