# US 9,434,023 B2 · Laser machining apparatus

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- Number: US 9,434,023 B2
- Document ID: US9434023B2
- Status: Granted
- Kind: B2
- Application number: 14/244,391
- Filed: 2014-04-03
- Published: 2014-10-09
- Granted: 2016-09-06
- Earliest claimed: 2013-04-05
- Assignees: Disco Corporation
- Applicants: Disco Corporation
- Inventors: Taiki Sawabe; Wakana Onoe; Tomohiro Endo
- Web page: https://patentgrep.com/patent/US9434023B2

## CPC

- B23K 26/032: {using optical means}
- B23K 26/04: Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
- B23K 26/042: Automatically aligning the laser beam
- B23K 26/359: by providing a line or line pattern, e.g. a dotted break initiation line
- G01B 11/00: Measuring arrangements characterised by the use of optical techniques
- H10P 72/50: for positioning, orientation or alignment
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A laser machining apparatus that includes an interferometric height position detection unit, a condensing point position adjustment unit, and a confocal optical height position detection unit. A controller of the laser machining apparatus specifies, as a correction value, the difference between the two height positions of the upper face of the workpiece, one detected by the confocal optical height position detection unit and the other detected by the interferometric height position detection unit. The controller controls the condensing point position adjustment unit based on the height position obtained by correcting the height position of the upper face of the workpiece detected by the interferometric height position detection unit using the correction value.

## Claims

### Claim 1

A laser machining apparatus comprising:
a chuck table having a holding face adapted to hold a workpiece;
laser beam irradiation means having an objective condenser lens adapted to condense and irradiate a laser beam onto the workpiece held by the chuck table;
interferometric height position detection means adapted to detect a height position of an upper face of the workpiece held by the chuck table based on the interference between light reflected from the upper face of the workpiece and reference light;
condensing point position adjustment means adapted to move the objective condenser lens vertically relative to the holding face of the chuck table;
control means adapted to control the condensing point position adjustment means based on the height position of the upper face of the workpiece detected by the interferometric height position detection means; and
confocal optical height position detection means adapted to detect the height position of the upper face of the workpiece held by the chuck table,
wherein the control means specifies, as a correction value, the difference between the two height positions of the upper face of the workpiece held by the chuck table, one detected by the confocal optical height position detection means and another detected by the interferometric height position detection means, and
the control means controls the condensing point position adjustment means based on the height position obtained by correcting the height position of the upper face of the workpiece detected by the interferometric height position detection means using the correction value.