ACOUSTO-OPTIC DEFLECTOR APPLICATIONS IN LASER PROCESSING OF DIELECTRIC OR OTHER MATERIALS

• US 20190329350A1
• Filed: 07/08/2019
• Published: 10/31/2019
• Est. Priority Date: 05/28/2009
• Status: Active Grant

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Inventors: Unrath, Mark A., Jordens, William J., Ismail, James, Matsumoto, Hisashi, Lineburg, Brian J.
• Granted Patent: US 11,738,405 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/046 Automatically focusing the laser beam
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved

Abstract

A laser processing system for micromachining a workpiece includes a laser source to generate laser pulses for processing a feature in a workpiece, a galvanometer-driven (galvo) subsystem to impart a first relative movement of a laser beam spot position along a processing trajectory with respect to the surface of the workpiece, and an acousto-optic deflector (AOD) subsystem to effectively widen a laser beam spot along a direction perpendicular to the processing trajectory. The AOD subsystem may include a combination of AODs and electro-optic deflectors. The AOD subsystem may vary an intensity profile of laser pulses as a function of deflection position along a dither direction to selectively shape the feature in the dither direction. The shaping may be used to intersect features on the workpiece. The AOD subsystem may also provide rastering, galvo error position correction, power modulation, and/or through-the-lens viewing of and alignment to the workpiece.

Claims

1. A method comprising:

generating a laser beam;

passing the laser beam through a first acousto-optic deflector (AOD) and a second AOD;

chirping a first RF signal applied to the first AOD; and

chirping a second RF signal applied to the second AOD,

wherein chirping both the first RF signal and the second RF signal selectively changes the spot size of the laser beam at a surface of a workpiece on a pulse-by-pulse basis to selectively change a width of a kerf cut in the surface of the workpiece by the laser beam

2. The method of the claim 1, wherein generating the laser beam comprises generating a series of laser pulses, the method further comprising selectively changing the spot size between successively generated laser pulses.

3. The method of the claim 1, further comprising, after passing the second diffracted laser beam through the scan lens, directing the second diffracted laser beam onto a workpiece to cut a kerf in the workpiece.

4. The method of the claim 1, wherein

the laser beam comprises a pluralityh of pulses, and

the generating of at least one selected from the group consisting of the first diffracted laser beam and the second diffracted laser beam is performed on a pulse-by-pulse basis.