Fast beam manipulation for cross-axis miromaching

Patent metadata

Field	Value
Publication number	US-10507544-B2
Application number	US-201615055037-A
Country	US
Kind code	B2
Filing date	Feb 26, 2016
Priority date	Feb 27, 2015
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A laser processing system includes a first positioning system (1044) for imparting first relative movement of a beam axis along a beam trajectory (1062) with respect to a workpiece (1060), a processor for determining a second relative movement of the beam axis (1061) along a plurality of dither rows, a second positioning system (1042) for imparting the second relative movement, and a laser source (1046) for emitting laser beam pulses. The laser beam pulses of individually selected energies can be directed to individually selected transverse spot locations (5310) one or more times during a primary laser pass to permit three-dimensional patterning. The laser beam pulses can also be directed to the spatially identical, overlapping, or non-overlapping neighboring spot area locations on the workpiece in a temporally nonsequential order.

First claim

The invention claimed is:

1. A method for dithering a laser beam to form a feature in a workpiece, the method comprising:
generating, from a laser source, multiple laser beam pulses along a laser beam path that forms a laser beam axis with respect to a surface of the workpiece;
imparting, using a first positioning system, first relative movement of the laser beam axis along a beam trajectory with respect to the surface of the workpiece, wherein the first positioning system provides a first beam deflection range;
imparting, using a second positioning system, a second relative movement of the laser beam axis superimposed on the first relative movement, wherein the second positioning system that provides a second beam deflection range that is smaller than the first beam deflection range, wherein the second relative movement comprises a non-zero direction component that is transverse to the beam trajectory; and
while imparting the first relative movement and the second relative movement, delivering a laser beam pulse to each of a plurality of selective spot locations on a workpiece, wherein the plurality of selective spot locations are simultaneously present within the second beam deflection range, wherein at least two temporally consecutive laser beam pulses delivered to the workpiece are delivered to a set of the selective spot locations within the plurality of spot locations, and wherein at least one selective spot location in the set of selective spot locations is located between two other selective spot locations in the set of selective spot locations.

2. The method of claim 1 , wherein the laser beam pulses delivered to the workpiece during the secondary laser pass provide three-dimensional patterning within the second beam deflection range, wherein the three-dimensional patterning includes patterning that is transverse to the beam trajectory and depthwise at two or more depths at respective spot locations with respect to the surface of the workpiece.

3. The method of claim 1 , wherein the second beam deflection range extends between 0.01 mm and 4.0 mm in transverse directions.

4. The method of claim 1 , further comprising controlling a spot size of the at least two temporally consecutive laser beam pulses to be different at different selective spot locations within the set of selective spot locations.

5. The method of claim 1 , wherein at least two selective spot locations within the set of selective spot locations are spatially noncontiguous.

6. The method of claim 1 , wherein the set of selective spot locations to which the at least two temporally consecutive laser beam pulses are delivered are at a distance from each other that is greater than or equal to 25% of the second beam deflection range.

7. The method of claim 1 , wherein the first relative movement is at a velocity that is greater than or equal to 50% of a maximum velocity of the first beam-positioning system.

8. The method of claim 1 , the second positioning system is operative to deflect the beam axis along more than one deflection axis.

9. The method of claim 1 , wherein multiple laser beam pulses are directed to one selective spot location during the primary laser pass along the beam trajectory.

10. The method of claim 1 , wherein the temporally sequential laser beam pulses delivered to the workpiece are delivered to selective non-neighboring spot locations along different axes with respect to the beam trajectory.

11. The method of claim 1 , wherein temporally sequential laser beam pulses delivered to the workpiece within a scan field of the second positioning system during the laser pass include 10 or greater laser beam pulses.

12. The method of claim 1 , wherein the beam axis is dithered transversely to the beam trajectory to widen the area machined by the laser during each laser pass.

13. The method of claim 1 , wherein the relative motion between the beam axis and the workpiece is greater than or equal to 400 mm/s along the beam trajectory.

14. The method of claim 1 , wherein the first positioning system employs one or more galvanometer-driven mirrors, and wherein the second positioning system comprises a zero-inertial positioning device.

15. The method of claim 14 , wherein the second positioning system comprises two or more acousto-optic devices (AODs).

16. The method of claim 1 , wherein the laser beam pulses have spot sizes at the workpiece, wherein the laser source generates a total number of the laser beam pulses during the primary laser pass along the beam trajectory while the laser beam axis is within the second beam deflection range, wherein the total number of the laser beam pulses exceed by greater than 25% a desirable number of working laser beam pulses for impinging the workpiece along the beam trajectory within a distance of one spot size from the beam trajectory, and wherein greater than 80% of the total number of the laser beam pulses are delivered to the workpiece during the primary laser pass along the beam trajectory while the laser beam axis is within the second beam deflection range.

17. The method of claim 1 , wherein the laser source generates a total number of the laser beam pulses during the primary laser along the beam trajectory while the laser beam axis is within the second beam deflection range, and wherein greater than 60% of the total number of the laser beam pulses are delivered to the workpiece during the primary laser along the beam trajectory while the laser beam axis is within the second beam deflection range.

18. The method of claim 1 , wherein the laser source generates a total number of the laser beam pulses during the primary laser along the beam trajectory while the laser beam axis is within the second beam deflection range, and wherein the total number of the laser beam pulses provide a total fluence that exceeds a working fluence of a processing window for impinging the workpiece with the total number of the laser beam pulses within 5 microns of the laser beam axis along the beam trajectory.

Assignees

• Electro Scient Ind Inc

Inventors

• Zhang Haibin
• Yang Chuan
• Unrath Mark Alan
• Orrick Martin

Classifications

• B23K26/36

  Removing material (B23K26/55, B23K26/57 take precedence) · CPC title

• B23K26/0608

  in the same heat affected zone [HAZ] (B23K26/0613, B23K26/0619 take precedence) · CPC title

• B23K26/0622 Primary

  by shaping pulses · CPC title

• B23K26/356

  by shock processing · CPC title

• B23K26/352

  for surface treatment · CPC title