Method and apparatus for laser machining relatively narrow and relatively wide structures
AssigneeM-Solv Limited
InventorPhilip Thomas Rumsby
Life of this patent
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Abstract
The method uses a common optical, system and sequentially creates structures of different sizes in a polymer substrate by means of different laser processes is described. One process uses a laser beam that is tightly focussed on the substrate surface and is used for creating fine groove structures by semi-continuous direct write type beam movement. The second process uses a second laser beam that is used to form a larger size image on the substrate surface and is used to create blind pads and contact holes in the substrate in step and drill mode. A third optional process uses the second laser beam operating in direct writing mode to remove layers of the substrate over larger continuous areas or in a mesh type pattern.
Claims20
Apparatus for the formation by laser ablation of relatively narrow grooves and relatively wide areas and/or holes in the surface of a dielectric layer comprising:
- laser apparatus for providing a first laser beam that is strongly absorbed by the dielectric layer and has substantially diffraction limited beam quality and which operates continuously or quasi-continuously for direct writing of the grooves and a second laser beam that is strongly absorbed by the dielectric layer and which operates in pulsed mode for forming the areas and/or holes via an image of an aperture or mask or via focal spot shaping;
- a common optical path comprising a beam scanner for deflecting the first and second laser beams in two orthogonal axes relative to the dielectric layer and a lens for focusing the first laser beam onto the surface of the dielectric layer and, when the second laser beam is used, for forming an image of said aperture or mask on the surface of the dielectric layer or for forming a shaped focal spot on the surface of the dielectric layer;
- and a control system arranged, in a first step, to drive the beam scanner so that a focused spot of the first laser beam is moved so as to vaporize the dielectric material to form relatively narrow grooves in the surface thereof and, in a second step, to drive the beam scanner so that a relatively wide laser spot from the second laser beam is incident on the surface of the dielectric layer and is moved to form relatively wide areas of defined depth in the surface thereof and/or is moved between a series of defined locations and the second laser beam held stationary at each location and a burst of laser pulses of sufficient number and energy is fired such that the dielectric material is vaporized to form a relatively wide hole of defined depth.
A method of forming relatively narrow grooves and relatively wide areas and/or holes in the surface of a dielectric layer by laser ablation comprising:
- providing a first laser beam that is strongly absorbed by the dielectric layer and has substantially diffraction limited beam quality and which operates continuously or quasi-continuously to directly write the grooves and providing a second laser beam that is strongly absorbed by the dielectric layer and which operates in pulsed mode to form the areas and/or holes via an image of an aperture or mask or via focal spot shaping;
- providing a common optical path comprising a beam scanner to deflect the first and second laser beams in two orthogonal axes relative to the dielectric layer and a lens to focus the first laser beam onto the surface of the dielectric layer and, when the second laser beam is used, to follu an image of said aperture or mask on the surface of the dielectric layer or to form a shaped focal spot on the surface of the dielectric layer;
- and providing a control system which, in a first step, drives the beam scanner so that a focused spot of the first laser beam is moved so as to vaporize the dielectric material to form relatively narrow grooves in the surface thereof and, in a second step, drives the beam scanner so that a relatively wide laser spot from the second laser beam is incident on the surface of the dielectric layer and is moved to form relatively wide areas of defined depth in the surface thereof and/or is moved between a series of defined locations, the second laser beam being held stationary at each location and a burst of laser pulses of sufficient number and energy is fired such that the dielectric material is vaporized to form a relatively wide hole of defined depth.
Dependencies are inferred from the claim text.