Method and system for calibrating a laser processing system and laser marking system utilizing same

• US 20060054608A1
• Filed: 11/04/2005
• Published: 03/16/2006
• Est. Priority Date: 05/17/2002
• Status: Abandoned Application

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: GSI Lumonics Corporation (Novanta Inc.)
• Inventors: Pelsue, Kurt, Ehrmann, Jonathan S., Cahill, Steven P., Schramm, Rainer, Li, You C.
• Application Number:
  US11/266,844
• Publication Number:
  US 20060054608A1
• Time in Patent Office: Days
• US Class Current: 219/121.830
• CPC Class Codes: B23K 2101/007 Marks, e.g. trade marks
• 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 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: B23K 26/043 along the beam path, i.e. alignment of laser beam axis relative to laser beam apparatus
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/705 Beam measuring device
• CPC Class Codes: G06K 1/126 by photographic or thermographic registration recording apparatus for measuring instruments G01D15/00
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H01L 21/67282 Marking devices
• CPC Class Codes: H01L 21/681 using optical controlling means
• CPC Class Codes: H01L 2223/5442 comprising non digital, non alphanumeric information, e.g. symbols
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 2223/54473 for use after dicing
• CPC Class Codes: H01L 2223/5448 Located on chip prior to dicing and remaining on chip after dicing
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method of calibrating a laser marking system includes calibrating a laser marking system in three dimensions. The step of calibrating includes storing data corresponding to a plurality of heights. A position measurement of a workpiece is obtained to be marked. Stored calibration data is associated with the position measurement. A method and system for calibrating a laser processing or marking system is provided. The method includes: calibrating a laser marker over a marking field; obtaining a position measurement of a workpiece to be marked; associating stored calibration data with the position measurement; relatively positioning a marking beam and the workpiece based on at least the associated calibration data; and calibrating a laser marking system in at least three degrees of freedom. The step of calibrating includes storing data corresponding to a plurality of positions and controllably and relatively positioning a marking beam based on the stored data corresponding to the plurality of positions.

Claims

1. A method of calibrating a laser marking system, the method comprising:

calibrating a laser marking system in three dimensions, the step of calibrating including storing data corresponding to a plurality of heights;

obtaining a position measurement of a workpiece to be marked; and

associating stored calibration data with the position measurement.

2. The method of claim 1 wherein the data is stored in multiple calibration files, the calibration files corresponding to a plurality of pre-determined marking system parameter settings.

3. The method of claim 2 wherein the multiple calibration files correspond to a height level and one of marker system parameter settings is a marking field dimension.

4. The method of claim 2 wherein one of the marking system parameter settings is a spot size.

5. The method of claim 2 wherein one of the marking system parameter settings is a working distance.

6. The method of claim 1 wherein the marking system is a backside wafer marking system having a fine alignment camera for obtaining reference data from a topside of the wafer.

7. A laser-based wafer marking system for marking a wafer having a topside containing a circuit, the circuit having circuit features, the wafer having a backside to be marked, the system comprising:

a calibrated galvanometer marking head having a scan lens and a marking field substantially smaller than the wafer;

a calibrated positioning stage for carrying the wafer with a range of motion large enough to position any wafer location to be marked to within the marking field;

a calibrated alignment camera with a field of view substantially smaller than the wafer;

a frame which mounts the stage rigidly with respect to the camera and the marking head; and

a controller having a map for coordinating locations of the marking head, stage, and alignment camera for causing the stage and the marking head to be positioned relative to each other such that the wafer is accurately marked on its backside relative to the circuit features on the front side.

8. The system of claim 7 where the alignment camera and the marking field are located on opposite sides of the wafer.

9. The system of claim 7 where the alignment camera is offset from the marking head.

10. The system of claim 7 where a mark inspection camera is offset from the marking field.

11. The system of claim 10 where the controller compares a location of a mark obtained from the inspection camera with a location of a circuit obtained with the alignment camera.

12. The system of claim 7 with a second alignment camera is offset from the marking field and a mark inspection camera is offset from the marking field on the backside of the wafer.

13. The system of claim 7 wherein the scan lens is a telecentric lens.

14. The system of claim 7 wherein the controller coordinates positioning of first and second wafer portions to be marked based on the map, and wherein the portions overlap the marking field.