Laser processing a workpiece
AssigneeM-Solv Limited
InventorPhillip Thomas Rumsby
Life of this patent
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Abstract
A method is described for simultaneously writing patterns in thin films of material coated on the opposite sides of thin glass or plastic substrates by direct write, laser ablation. The substrates are fully or partially transparent to the laser radiation used and in addition the surfaces of the substrates are not assumed to be flat. Different registered patterns may be applied at the same time to opposite sides of the substrates.
Claims20
A method of processing a workpiece, the workpiece comprising a transparent substrate having first and second films respectively formed on first and second surfaces thereof, by direct-write laser ablation, the method comprising:
- positioning a first lens unit of a first laser beam delivery apparatus facing the first surface of the substrate to direct-write the first film on the first surface of the transparent substrate, the transparent substrate being transparent to laser radiation;
- and
- direct-writing the first film on the first surface of the transparent substrate with a first laser beam from the first lens unit being focused at an intermediate point between the first lens unit and the first film such that a focal point of the first laser beam falls short of the first film and the first laser beam is diverging as it impinges on the first film and continues through the transparent substrate and impinges on the second film during the direct-writing of the first film, wherein
- an energy of the first laser beam and a distance between the focal point of the first laser beam and the first film are set such that an energy density which the first film is subjected to by the first laser beam is greater than an ablation threshold energy density of the first film and an energy density which the second film is subjected to by the first laser beam is less than an ablation threshold energy density of the second film on the second surface of the transparent substrate, such that the first film is removed by the first laser beam in an area where the first laser beam impinges on the first film, and the second film is undamaged by the first laser beam in an area where the first laser beam impinges on the second film during the direct-writing of the first film.
A system for processing a workpiece, the workpiece comprising a transparent substrate having first and second films respectively formed on first and second sides thereof, by direct write laser ablation, the system comprising:
- a first laser beam delivery apparatus comprising a first laser beam scanner and a first lens unit;
- a carrier configured to receive a workpiece thereon;
- and
- a mounting device for mounting the first laser beam delivery apparatus and the carrier for relative movement to permit the direct-writing of the first film on the first side of the transparent substrate, the transparent substrate being transparent to laser radiation, wherein a first laser beam of the first lens unit of the first laser beam delivery apparatus is focused at an intermediate point between the first lens unit and the first film such that a first focal point falls short of the first film and the first laser beam is diverging as it impinges on the first film and continues through the transparent substrate and impinges on the second film during the direct-writing of the first film, wherein:
- an energy of the first laser beam and a distance from the first focal point to the first film are set such that an energy density which the first film is subjected to by the first laser beam is greater than an ablation threshold energy density of the first film and an energy density which the second film is subjected to by the first laser beam is less than an ablation threshold energy density of the second film on the second side of the transparent substrate, such that the first film is removed by the first laser beam in an area where the first laser beam impinges on the first film, and the second film is undamaged by the first laser beam in an area where the first laser beam impinges on the second film during the direct-writing of the first film.
Dependencies are inferred from the claim text.