Steven Boyd Cahill

US Patent:

6483071, Nov 19, 2002

Filed:

May 16, 2000

Appl. No.:

09/572925

Inventors:

Bradley L. Hunter - Lexington MA
Steven P. Cahill - Newton MA
Jonathan S. Ehrmann - Sudbury MA
Michael Plotkin - Newton MA

Assignee:

General Scanning Inc. - Wilmington MA

International Classification:

B23K 2602

US Classification:

2191216, 21912181

Abstract:

A high-speed method and system for precisely positioning a waist of a material-processing laser beam to dynamically compensate for local variations in height of microstructures located on a plurality of objects spaced apart within a laser-processing site are provided. In the preferred embodiment, the microstructures are a plurality of conductive lines formed on a plurality of memory dice of a semiconductor wafer. The system includes a focusing lens subsystem for focusing a laser beam along an optical axis substantially orthogonal to a plane, an x-y stage for moving the wafer in the plane, and a first air bearing sled for moving the focusing lens subsystem along the optical axis. The reference data is generated by the system which includes a modulator for reducing power of the material-processing laser beam to obtain a probe laser beam to measure height of the semiconductor wafer at a plurality of locations about the site to obtain reference height data. A computer computes a reference surface based on the reference height data. A trajectory planner generates trajectories for the wafer and the waist of the laser beam based on the reference surface.

US Patent:

6573473, Jun 3, 2003

Filed:

Nov 2, 2001

Appl. No.:

10/001104

Inventors:

Bradley L. Hunter - Lexington MA
Steven P. Cahill - Newton MA
Jonathan S. Ehrmann - Sudbury MA
Michael Plotkin - Newton MA

Assignee:

General Scanning Inc. - Wilmington MA

International Classification:

B23K 2602

US Classification:

21912169

Abstract:

A high-speed method and system for precisely positioning a waist of a material-processing laser beam to dynamically compensate for local variations in height of microstructures located on a plurality of objects spaced apart within a laser-processing site are provided. In the preferred embodiment, the microstructures are a plurality of conductive lines formed on a plurality of memory dice of a semiconductor wafer. The system includes a focusing lens subsystem for focusing a laser beam along an optical axis substantially orthogonal to a plane, an x-y stage for moving the wafer in the plane, and a first air bearing sled for moving the focusing lens subsystem along the optical axis.

US Patent:

6744228, Jun 1, 2004

Filed:

Jul 11, 2000

Appl. No.:

09/613833

Inventors:

Steven P. Cahill - Newton MA
Bradley L. Hunter - Lexington MA

Assignee:

GSI Lumonics Corp. - Billerica MA

International Classification:

H01L 2168

US Classification:

318135, 318687, 355 53

Abstract:

A high-speed precision positioning apparatus has a stage supported by a platen. The stage is driven by a plurality of drive motors that are co-planar with the stage and arranged symmetrically around the stage. The drive motors apply drive forces directly to the stage without any mechanical contact to the stage. The drive forces impart planar motion to the stage in at least three degrees of freedom of motion. In the remaining three degrees of freedom the motion is constrained by a plurality of fluid bearings that operate between the stage and the platen. The drive motors are configured as magnets, attached to the stage, moving in a gap formed in-between top and bottom stationary coils. Integral force cancellation is implemented by a force cancellation system that applies cancellation forces to the stage. The cancellation forces, which are co-planar with a center of gravity of the stage and any components that move with the stage, cancel forces generated by planar motion of the stage. Interferometric encoders are used as position detectors.

US Patent:

6949844, Sep 27, 2005

Filed:

Dec 29, 2003

Appl. No.:

10/747552

Inventors:

Steven P. Cahill - Newton MA, US
Bradley L. Hunter - Lexington MA, US

Assignee:

GSI Group Corporation - Billerica MA

International Classification:

H02K021/00

US Classification:

310 12, 355 53, 355 72

Abstract:

A high-speed precision positioning apparatus has a stage supported by a platen. The stage is driven by a plurality of drive motors that are co-planar with the stage and arranged symmetrically around the stage. The drive motors apply drive forces directly to the stage without any mechanical contact to the stage. The drive forces impart planar motion to the stage in at least three degrees of freedom of motion. In the remaining three degrees of freedom the motion is constrained by a plurality of fluid bearings that operate between the stage and the platen. The drive motors are configured as magnets, attached to the stage, moving in a gap formed in-between top and bottom stationary coils. Integral force cancellation is implemented by a force cancellation system that applies cancellation forces to the stage. The cancellation forces, which are co-planar with a center of gravity of the stage and any components that move with the stage, cancel forces generated by planar motion of the stage. Interferometric encoders are used as position detectors.

US Patent:

7015418, Mar 21, 2006

Filed:

May 15, 2003

Appl. No.:

10/438533

Inventors:

Steven P. Cahill - Newton MA, US
Jonathan S. Ehrmann - Sudbury MA, US
You C. Li - Reading MA, US
Rainer Schramm - Everett MA, US
Kurt Pelsue - Wayland MA, US

Assignee:

GSI Group Corporation - Billerica MA

International Classification:

B23K 26/00

US Classification:

21912169, 21912168

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.

US Patent:

7176407, Feb 13, 2007

Filed:

Apr 26, 2005

Appl. No.:

11/114520

Inventors:

Bradley L. Hunter - Lexington MA, US
Steven P. Cahill - Newton MA, US
Jonathan S. Ehrmann - Sudbury MA, US
Michael Plotkin - Newton MA, US

Assignee:

GSI Group Corporation - Novi MI

International Classification:

B23K 26/02

US Classification:

2191217

Abstract:

A high-speed method and system for precisely positioning a waist of a material-processing laser beam to dynamically compensate for local variations in height of microstructures located on a plurality of objects spaced apart within a laser-processing site are provided. In the preferred embodiment, the microstructures are a plurality of conductive lines formed on a plurality of memory dice of a semiconductor wafer. The system includes a focusing lens subsystem for focusing a laser beam along an optical axis substantially orthogonal to a plane, an x-y stage for moving the wafer in the plane, and a first air bearing sled for moving the focusing lens subsystem along the optical axis.

US Patent:

7469831, Dec 30, 2008

Filed:

Oct 27, 2006

Appl. No.:

11/514660

Inventors:

Bo Gu - North Andover MA, US
Jonathan S. Ehrmann - Sudbury MA, US
Donald J. Svetkoff - Ann Arbor MI, US
Steven P. Cahill - Newton MA, US
Kevin E. Sullivan - Everett MA, US

Assignee:

GSI Group Corporation - Billerica MA

International Classification:

G06K 7/10

US Classification:

235454, 21912162, 438463

Abstract:

A laser-based method and system for processing targeted surface material and article produced thereby are provided. The system processes the targeted surface material within a region of a workpiece while avoiding undesirable changes to adjacent non-targeted material. The system includes a primary laser subsystem including a primary laser source for generating a pulsed laser output including at least one pulse having a wavelength and a pulse width less than 1 ns. A delivery subsystem irradiates the targeted surface material of the workpiece with the pulsed laser output including the at least one pulse to texture the targeted surface material. The pulsed laser output has sufficient total fluence to initiate ablation within at least a portion of the targeted surface material and the pulse width is short enough such that the region and the non-targeted material surrounding the material are substantially free of slag.

US Patent:

20030116726, Jun 26, 2003

Filed:

Nov 18, 2002

Appl. No.:

10/298838

Inventors:

Bradley Hunter - Lexington MA, US
Steven Cahill - Newton MA, US
Jonathan Ehrmann - Sudbury MA, US
Michael Plotkin - Newton MA, US

Assignee:

General Scanning, Inc. - Wilmington MA

International Classification:

G01V008/00
G01N021/86

US Classification:

250/559380

Abstract:

A high-speed method and system for precisely positioning a waist of a material-processing laser beam to dynamically compensate for local variations in height of microstructures located on a plurality of objects spaced apart within a laser-processing site are provided. In the preferred embodiment, the microstructures are a plurality of conductive lines formed on a plurality of memory dice of a semiconductor wafer. The system includes a focusing lens subsystem for focusing a laser beam along an optical axis substantially orthogonal to a plane, an x-y stage for moving the wafer in the plane, and a first air bearing sled for moving the focusing lens subsystem along the optical axis. The system also includes a first controller for controlling the x-y stage based on reference data which represents 3-D locations of microstructures to be processed within the site, a second controller, and a first voice coil coupled to the second controller for positioning the first air bearing sled along the optical axis also based on the reference data. The reference data is generated by the system which includes a modulator for reducing power of the material-processing laser beam to obtain a probe laser beam to measure height of the semiconductor wafer at a plurality of locations about the site to obtain reference height data. A computer computes a reference surface based on the reference height data. A trajectory planner generates trajectories for the wafer and the waist of the laser beam based on the reference surface. The x-y stage and the first air bearing sled controllably move the wafer and the focusing lens subsystem, respectively, to precisely position the waist of the laser beam so that the waist substantially coincides with the 3-D locations of the microstructures within the site. The system also includes a spot size lens subsystem for controlling size of the waist of the laser beam, a second air bearing sled for moving the spot size lens subsystem along the optical axis, a third controller for controlling the second air bearing sled, and a second voice coil coupled to the third controller for positioning the second air bearing sled along the optical axis.