Multiple beam micro-machining system and method Number:7,521,651 from the United States Patent and Trademark Office (PTO) owispatent A system for delivering energy to a substrate including a dynamically directable source of radiant energy providing a plurality of beams of radiation, each propagating in a dynamically selectable direction. Independently positionable beam steering elements in a plurality of beam steering elements are operative to receive the beams and direct them to selectable locations on the substrate.<H machining, Multiple, Multiple, beam, m, 7521651.html, Patent, pto, 7521651

Title: Multiple beam micro-machining system and method

Abstract: A system for delivering energy to a substrate including a dynamically directable source of radiant energy providing a plurality of beams of radiation, each propagating in a dynamically selectable direction. Independently positionable beam steering elements in a plurality of beam steering elements are operative to receive the beams and direct them to selectable locations on the substrate.

Patent Number: 7,521,651 Issued on 04/21/2009 to Gross, et al.

Inventors: Gross; Abraham (Ramat Aviv, IL), Kotler; Zvi (Tel Aviv, IL), Lipman; Eliezer (Rishon Lezion, IL), Alon; Dan (Mizpe Yericho, IL)
Assignee: Orbotech Ltd (Yavne, IL)

Appl. No.: 10/660,730

Filed: September 12, 2003

Current U.S. Class: 219/121.71 ; 219/121.77; 219/121.78

Current International Class: B23K 26/067 (20060101); B23K 26/38 (20060101)

Field of Search: 219/121.63-121.72,121.76,121.77,121.85,121.7

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Primary Examiner: Heinrich; Samuel M
Attorney, Agent or Firm: Sughrue Mion, PLLC

Claims

What is claimed is:

1. A method for delivering laser energy to an electrical circuit substrate, comprising: simultaneously outputting a plurality of laser beams from a laser beam source; independently steering said plurality of laser beams to impinge on said electrical circuit substrate at independently selectable locations; and independently optically focusing ones of said plurality of laser beams to different independently selectable locations, said independently focusing comprising moving at least one optical element, thus changing a focal length of an optical beam, associated with one of the plurality of laser beams to be focused, without f-theta optical elements.

2. The method claimed in claim 1, wherein said simultaneously outputting comprises outputting a first laser beam, and splitting said first laser beam into said plurality of laser beams.

3. The method claimed in claim 2, wherein said splitting comprises splitting said first laser beam with an acousto-optical deflector.

4. The method claimed in claim 3, wherein said splitting comprises directing ones of said plurality of laser beams in independently selectable directions.

5. The method claims in claim 1, wherein the at least one optical element is a refractive optical element.

6. The method claims in claim 1, wherein the at least one optical element is included within a focusing module.

7. The method of claims in claim 6, wherein the moving of the at least one optical element corresponds to a movement of the at least one optical module within the focusing module.

8. The method of claims in claim 1, wherein the moving of the at least one optical element comprises moving the at least one optical element in a direction of the optical beam passing through the optical element.

9. The method claims in claim 1, wherein the at least one optical element comprises a first set of optical elements and a second set of optical elements and the moving at least one optical element comprises moving the first set of optical elements independently of the second set of optical elements, thus independently changing a focal length of a first optical beam, passing through the first set of optical elements, and a second optical beam, passing through the second set of optical elements.

10. The method of claims in claim 1, wherein the moving of the at least one optical element comprises independently moving the at least one optical element in a direction of the optical beam passing through the optical element.

Description

FIELD OF THE INVENTION

The present invention generally relates to multiple laser beam positioning and energy deliver systems, and more particularly to laser micro-machining systems employed to form holes in electrical circuit substrates.

BACKGROUND OF THE INVENTION

Various laser systems are employed to micro-machine and otherwise thermally process substrates. Conventional laser systems employ focusing optics positioned between a beam steering device and a substrate to focus the beam onto the substrate.

A laser micro-machining device employing multiple independently positionable laser beams is described in copending U.S. patent application Ser. No. 10/170,212, filed Jun. 13, 2002 and entitled "Multiple Beam Micro-Machining System and Method", the disclosure of which is incorporated by reference in its entirety.

A laser device employing multiple independently positionable laser beams for thermally treating thin film materials, for example thin films on flat panel display substrates, is described in copending PCT application PCT/IL03/00142, filed Feb. 24, 2003 and entitled "Method for Manufacturing Flat Panel Display Substrates", the disclosure of which is incorporated by reference in its entirety.

SUMMARY OF INVENTION

The present invention seeks to provide an improved multiple beam laser beam energy delivery system, for simultaneously delivering multiple beams of focused laser energy to a substrate, that avoids the use of an f-theta (f-.theta.) scan lens.

The present invention further seeks to provide an improved multiple beam laser beam energy delivery system, for simultaneously delivering multiple beams of focused laser energy to a substrate, that avoids focusing optics situated between a beam steering device and the substrate.

The present invention still further seeks to provide an improved multiple beam laser beam energy delivery system, for delivering multiple beams of laser energy to a substrate, that independently focuses each of the multiple laser beams. In accordance with an embodiment of the invention, each of the multiple laser beams is independently focused upstream of a beam steering assembly.

The present invention still further seeks to provide an integrated multiple laser beam energy delivery system, for delivering multiple beams of laser energy to a substrate, operative to independently steer each of the laser beams, and to independently focus each of the laser beams in coordination with the beam steering.

The present invention still further seeks to provide a multiple laser beam laser energy delivery system operative to deliver laser energy to independently selectable locations on a workpiece, the device having an array of beam steering modules located downstream of beam focusing optics. In accordance with an embodiment of the present invention, the beam focusing optics are operative to independently focus each of the multiple laser beams onto a selectable location.

The present invention still further seeks to provide a multiple laser beam energy delivery system, for delivering multiple beams of laser energy to a workpiece, having a redundant number of independent focusing modules relative to a number of laser beams. The system is operative to use some focusing modules to deliver focused laser beams to a first set of locations on the substrate and to simultaneously move other focusing modules into focus to subsequently deliver focused laser beams to a second set of locations on the substrate. In accordance with an embodiment of the invention, the time required to move a focusing module into focus is greater than the time required to select a focusing module. The time required to switch between focusing modules is less than the time interval between adjacent pulses.

The present invention still further seeks to provide an improved multiple beam laser beam energy delivery system, for delivering multiple beams of laser energy to a workpiece, that includes a quantity laser beam focusing modules that is greater than the quantity of laser beams, and a beam director that is used to direct each beam to a selectable focusing module. While delivering focused laser energy to a first set of selectable locations on a substrate via a first set of laser beam focusing modules, other laser beam focusing modules are moved into focus for later delivery of focused laser energy to a next different of selectable locations.

There is thus provided in accordance with an embodiment of the present invention and apparatus and method for delivering laser energy to a workpiece, including at least one laser energy source providing at least one laser beam; and a plurality of laser beam modules arranged to selectably steer the at least one laser beam to a plurality of target sub-areas on a workpiece, which together cover a target area, the plurality of laser beam modules being additionally operative to focus the at least one laser beam on the workpiece without an intervening f-theta lens.

There is thus provided in accordance with another embodiment of the present invention an apparatus and method for delivering laser energy to a workpiece, including at least one pulsed laser energy source operating at a pulse repetition rate and providing at least one pulsed laser beam; and a plurality of laser beam focusing optical modules arranged to selectably focus each of the at least one laser beam to a selected location on a workpiece, the plurality of laser beam focusing optical modules being of a number greater than the at least one laser beam, thereby to define at least one redundant laser beam focusing optical module.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for delivering laser energy to a workpiece, including at least one laser energy source providing at least one laser beam; a plurality of laser beam steering modules arranged to selectably steer the at least one laser beam to selectable locations on a target; and a plurality of laser beam focusing optical modules associated with the laser beam steering modules for focusing a laser beam onto the workpiece.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for delivering laser energy to workpiece, including a laser energy source providing at least two laser beams for delivering laser energy to a workpiece at least at two different locations; at least two optical elements receiving the at least two laser beams, the at least two optical elements being operative to simultaneously independently control a beam parameter of each of the at least two laser beams; and a laser beam steering assembly receiving the at least two laser beams and being operative to independently steer the at least two laser beams to independently selectable locations on an in-fabrication electrical circuit.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for delivering laser energy to an electrical circuit substrate, including at least one laser beam source simultaneously outputting a plurality of laser beams; a plurality of independently steerable laser beam deflectors disposed between the at least one laser beam source and the electrical circuit substrate to direct the plurality of laser beams to impinge on the electrical circuit substrate at independently selectable locations; and focusing optics operative to focus the plurality of laser beams to different independently selectable locations without f-theta (f-.theta.) optical elements.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for delivering laser energy to a substrate including: at least one pulsed laser energy source providing at least one pulsed laser beam; a plurality of laser beam steering modules arranged to selectably steer the at least one laser beam to selected locations on a target at differing focal lengths, the plurality of laser beam steering modules being of a number greater than the at least one laser beam, thereby to define at least one redundant beam steering module; a plurality of laser beam automatic focusing optical modules upstream of the plurality of laser beam steering modules for automatically focusing a laser beam passing therethrough to a corresponding laser beam director module, to compensate for the differing focal lengths, the plurality of laser beam automatic focusing optical being of a number greater than the at least one laser beam, thereby to define at least one redundant laser beam automatic focusing optical module, the redundancy in the plurality of laser beam director modules and the plurality of laser beam automatic focusing optical modules compensating for a difference between a pulse repetition rate of the at least one pulsed laser energy source and a cycle time of the automatic focusing optical module.

Various embodiments of the invention include one or more of the following features and characteristics. It is noted, however, that some of the following components, features and characteristics may be found alone or in combination with other features and characteristics; some of the following components, features and characteristics refine others; and the implementation of some of the following components, features and characteristics excludes implementation of other components, features and characteristics.

A laser energy source comprises a laser and a laser beam splitter operative to convert an output of the laser into a plurality of laser beams.

A laser energy source comprises a laser and a laser beam director operative to receive an output of the laser and to provide a plurality of individually directed laser beams.

A beam splitter is operative to receive a laser beam and to output each of at least two laser beams in independently selectable directions.

A laser energy source comprises a laser and an AOD (acousto-optical device) operative to split an output of the laser into a selectable number of laser beams and to individually direct each laser beam to a selectable location.

Laser beam modules comprise at least one laser beam steering module operative to steer at least one laser beam to a selectable location on the workpiece, and at least one laser beam focusing optical module upstream of the at least one laser beam steering module operative to focus the at least one laser beam onto the workpiece.

Optionally, laser beam modules comprise at least one laser beam steering module operative to steer at least one laser beam to a selectable location on the workpiece and to selectively extend or retract to compensate for an actual distance to the selectable location to thereby deliver the at least one laser beam in focus onto the workpiece.

Laser beam modules comprise a plurality of laser beam steering modules arranged in an array, each laser beam steering module being operative to steer a laser beam to a selectable location in a corresponding target sub-area.

Each laser beam steering module is operative to steer a laser beam to a selectable location independent of other laser beam steering modules.

Laser beam focusing optical modules operate in coordination with a corresponding laser beam steering module, the focusing optical modules being operative to focus a laser beam onto the workpiece at a selectable location.

Laser beam modules comprise a plurality of laser beam steering modules and a corresponding plurality of laser beam focusing optical modules. Each laser beam focusing optical module is operative to focus a laser beam to any selectable location in a target sub-area.

The laser beam modules include at least one redundant laser beam module.

The laser beam is a pulsed laser beam. During an initial pulse, a first laser beam steering module is operative to steer a laser beam in focus to a first selectable location. During a subsequent pulse, a second laser beam steering module is operative to steer at least one laser beam in focus to a second selectable location different from the first selectable location.

A laser beam steering module is arranged to selectably steer a laser beam to a selectable location in a target sub-area. At least some selectable locations in the target sub-area are located at differing focusing distances from a corresponding focusing optical module. Focusing is achieved by dynamically changing a focus parameter of the focusing optical module.

A laser beam can be selectably directed to a selectable laser beam focusing optical module. A redundancy in the laser beam focusing optical modules respective of the laser beams compensates for a difference between the pulse repetition rate and a cycle time of each of the laser beam focusing optical modules.

During a first pulse of the pulsed laser energy source, a first laser beam focusing optical module is operative to focus a first pulsed laser beam onto a workpiece.

During a first pulse of the pulsed laser source, a redundant laser beam focusing optical module is repositioned to a position required to focus a subsequent pulsed laser beam onto the workpiece at a subsequent selectable location, the subsequent pulsed laser beam being output during a subsequent pulse of the pulsed laser energy source.

A pulsed laser energy source is operative to provide a plurality of pulsed laser beams during each pulse.

A pulsed laser energy source is operative to provide a plurality of pulsed laser beams for each pulse, and the plurality of laser beam focusing optical modules includes an at least one redundant laser beam focusing optical module respective of each laser beam.

A cycle time for configuring a laser beam focusing optical module to focus a laser beam onto the workpiece exceeds a time interval separating pulses of the at least one pulsed laser source.

A pulsed laser energy source comprises a deflector selectably deflecting the at least one pulsed laser beam. A cycle time of the deflector is less than a time interval between pulses of the pulsed laser source.

During an initial pulse of the pulsed laser energy source the deflector is operative to deflect an initial laser beam to a first laser beam focusing optical module, and during a next pulse the deflector is operative to deflect a next laser output to a redundant laser beam focusing optical module.

A plurality of laser beam steering modules is provided downstream of the plurality of laser beam focusing optical modules for steering a laser beam to a selectable location on the workpiece.

Laser beam focusing modules include a selectively pivoting mirror operative to be extended or retracted to compensate for changes in distance to a flat surface resulting from a pivoting action.

A laser beam focusing module comprises at least one actuator operative to move a portion of the laser beam steering module to compensate for changes in a length of an optical path as a function of steering the at least one laser beam.

A pulsed laser comprises a Q-switched pulsed laser.

A pulsed laser outputs a laser beam in the ultra-violet spectrum.

A laser beam steering assembly comprises a plurality of laser beam steering modules. The laser beam steering modules is arranged in a two dimensional array of laser beam steering modules.

A focusing assembly comprises at least two dynamically movable optical elements arranged in an array of lens modules.

A changeable beam parameter is a focus parameter. Focusing modules are operative to simultaneously independently focus at least two laser beams at respective independently selectable locations. The at least two laser beams are derived from the same laser beam source.

An array of focusing modules is disposed between the laser beam source and a laser beam steering assembly.

A focusing module comprises at least one lens element being independently movable respective of a movable lens element in another focusing module.

A controller is operative to independently move movable lens elements to independently focus at least two laser beams at respective independently selectable locations.

A zoom lens element is operative to receive at least two laser beams and to change a beam diameter property of the laser beams.

A laser beam is deliverable in focus to an independently selectable location among a plurality of selectable locations within a target sub-area. At least some of the independently selectable locations have different focus parameters. Focus is achieved by independently dynamically focusing each of the beams.

Focusing modules are operative to focus each laser beams at an independently selectable location as a function of a corresponding focusing distance.

A beam steering assembly comprises at least two actuators each coupled to a reflector to independently pivot each reflector. The actuators are further operative to extend or retract each reflector to independently adjust a beam focus parameter of the at least two laser beams.

The laser beams are operative to deliver laser energy to generate a via hole in an in-fabrication electrical circuit.

The laser beams are operative to deliver laser energy to trim a passive electrical component in an in-fabrication electrical circuit.

An in-fabrication electrical circuit is an in-fabrication printed circuit board, in-fabrication integrated circuit, an in-fabrication flat panel display.

The laser beams are operative to deliver laser energy to anneal silicon in an in-fabrication electrical circuit, such as an in-fabrication flat panel display.

The laser beams are operative to deliver laser energy to facilitate ion implantation in an in-fabrication electrical circuit, such as in-fabrication integrated circuit or in-fabrication flat panel display.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for dynamically splitting a laser beam, including a beam deflector having a plurality of operative regions, the beam deflector being operative to receive a laser beam at a first one of the plurality of operative regions and to provide a selectable number of output beam segments in response to a control input signal.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for dynamically deflecting a laser beam, including a beam deflector element having a plurality of operative regions, the beam deflector element being operative to receive an input laser beam at a first one of the plurality of operative regions and to provide a plurality of output beam segments output at least from one additional operative region, at least one output beam being independently deflected in response to a first control input signal.

There is thus provided in accordance with still another embodiment of the present invention an apparatus and method for dynamically splitting a laser beam, including a beam deflector having a plurality of operative regions being operative to receive a laser beam at a first one of the operative regions; and further being responsive to a control input signal to generate a selectable number of output beam segments, at least one output beam being output from a second operative region.

Various embodiments of these aspects of the invention include one or more of the following features and characteristics. It is noted, however, that some of the following components, features and characteristics may be found alone or in combination with other features and characteristics; some of the following components, features and characteristics refine others; and the implementation of some of the following components, features and characteristics excludes implementation of other components, features and characteristics.

A control input signal controlling the beam splitter/deflector comprises a sequence of pulses, each of the pulses controlling a respective output beam segments.

Each of the output beams has an energy parameter that is controlled by a characteristic of the control input signal.

Each of the output beam segments is deflected by a respective deflection angle that is controlled by a characteristic of a pulse in the control input signal.

Each of the output beam segments has substantially the same cross sectional configuration, irrespective of the selectable number of output beam segments.

The selectable number of output beam segments have a controllable energy parameter. The energy parameter is an energy density or fluence.

The energy densities among output beam segments is selectable to be substantially uniform. Optionally, it is selectable to be substantially not uniform.

The beam deflector is operative to direct the output beam segments in respective selectable directions responsive to the control input signal.

The beam deflector comprises an acousto-optic deflector, and a transducer to generate acoustic waves in the acousto-optic deflector in response to the control input signal. The deflector diffracts the laser beam at each of several operative regions as a function of the acoustic wave formed by the control input signal.

A beam redirector is operative to receive an output beam segment directed in a second direction from a first one of the plurality of operative regions and to direct the output beam segment to second ones of the plurality of operative regions.

A beam redirector comprises a first mirror having a plurality of regions, each region passing to the operative regions of a beam splitter/deflector a portion of a redirected beam and reflecting to a parallel mirror a remaining portion of the redirected beam.

Beam segments output by the beam reflector/deflector are mutually non-parallel.

An input laser beam has a spatial cross-section in the first one of the plurality of operative regions. A beam redirector comprises correction optics, which operate on redirected output beam segment so that the spatial cross section of the redirected output beam segment is substantially similar to the spatial cross section of the input beam.

A control input signal has a frequency characteristic, which controls the beam direction, and an amplitude characteristic, which controls an energy parameter of an output beam.

Each of the above devices and methods may be employed as part of process for manufacturing electrical circuits in which laser energy is delivered to an electrical circuit substrate, for example to ablate a material at a selected location, or as part of an annealing or ion implantation process. An additional electrical circuit manufacturing operation, such as, but not limited to, an additional photolithography, etching or metal deposition process, typically is performed on the electrical circuit substrate.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

FIG. 1A is a simplified partially pictorial , partially block diagram, illustration of apparatus for fabricating electrical circuits constructed and operative in accordance with a preferred embodiment of the present invention;

FIG. 1B is a timing graph of laser pulses output by a laser used in the system and functionality of FIG. 1;

FIGS. 2A-2C are simplified side view illustrations showing operation of a portion of the apparatus of FIG. 1A in three different operative orientations;

FIGS. 3A-3C are simplified schematic illustrations of an AOD suitable for use in the system of FIG. 1 in accordance with an embodiment of the invention; and

FIG. 4 is a flow diagram of a method for manufacturing electrical circuits in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIG. 1A, which is a simplified partially pictorial , partially block diagram, illustration of a system and functionality for fabricating an electrical circuit, constructed and operative in accordance with a preferred embodiment of the present invention, and to FIG. 1B which is a timing graph of laser pulses output by a laser used in the system and functionality of FIG. 1A. The system seen in FIG. 1A includes laser micro-machining apparatus 10, which in general terms is operative to simultaneously deliver multiple beams of energy to a workpiece, such as an electrical circuit substrate.

Apparatus 10 is particularly useful in the context of micro-machining holes, such as vias 12, at locations 13, in printed circuit board substrates 14, during the fabrication of printed circuit boards. Apparatus 10 may be adapted without departing from the presently described invention for use in other suitable fabrication processes employing micro-machining or heat treating of substrates. These processes include, without limitation, the selective annealing of amorphous silicon in flat panel displays, selective laser assisted doping of semiconductor transistors such as thin film transistors on flat panel displays, the removal of solder masks from electrical circuits, and the trimming of passive electronic components, such as imbedded resistors in printed circuit boards and bumps on ball grid array substrates and "flip-chip" type semiconductor circuits. Accordingly, although the invention is described in the context of micro-machining printed circuit boards, the scope of the invention should not be limited solely to this application.

Printed circuit board substrates, such as a substrate 14, which are suitable to be micro-machined using systems and methods described hereinbelow, typically include dielectric substrates, for example epoxy glass, having one or more electrical circuit layers. Typically, a conductor pattern 16 is selectively formed on each electrical circuit layer. The substrates may be formed of a single layer or, in the alternative, of a laminate including several substrate layers adhered together. Additionally, the outermost layer of the substrate 14 may comprise the conductor pattern 16 formed thereon, as seen in FIG. 1A. Alternatively, the outermost layer of substrate 14 may comprise, for example, a metal foil substantially overlaying a continuous portion of the outer surface of the substrate 14, for example as shown by the region indicated by reference numeral 17. In the context of other related applications, substrate 14 may be, for example, an in-fabrication flat panel display.

In accordance with an embodiment of the invention, as seen in FIG. 1A, laser micro-machining apparatus 10 includes a pulsed laser 20 outputting a pulsed laser beam 22. Pulsed laser beam 22 is defined by a stream of light pulses, schematically indicated by peaks 24 and 25 in laser pulse graph 26 (FIG. 1B). In accordance with an embodiment of the invention pulsed laser 20 is a frequency tripled Q-switched YAG laser providing a pulsed a UV laser beam 22 at a pulse repetition rate of between about 10-100 KHz, and preferably at about 10-30 KHz. Suitable Q-switched lasers are presently available, for example, from Spectra Physics, Lightwave Electronics and Coherent, Inc. all of California, U.S.A. Other commercially available pulsed lasers, that suitably interact with typical materials employed to manufacture printed circuit boards, may also be used.

Another suitable laser for use as pulsed laser 20, operative to output a pulsed UV laser beam particularly suitable for micro-machining substrates containing glass, is described in the present Applicants' copending U.S. patent application Ser. No. 10/167,472, the disclosure of which is incorporated by reference in its entirety.

In the embodiment seen in FIG. 1A, pulsed laser beam 22 impinges on a first lens 28, such as a cylindrical lens, operative to flatten beam 22 into a narrow beam 23 having a waist which is delivered to an image plane (not seen) in a first variable deflector assembly, such as an acousto-optical deflector (AOD) 30. Preferably AOD 30 includes a transducer element 32 and a translucent crystal member 34 formed of quartz or other suitable crystalline material.

It is noted that various design details of micro-machining apparatus 10 seen in FIG. 1A, which are well within the competence of a skilled optical designer, are omitted in an effort to maintain clarity and avoid obscuring key teaching points of the invention. For example, various lenses and optical paths are not drawn to scale. Moreover, some lenses, for example (but not limited to) lens 28, include several separate lens elements which are not shown. Likewise beam stabilization means within the competence of a skilled optical designer, as typically would be required in a complex laser energy delivery system, are omitted from the drawings to maintain clarity and avoid obscuring key teaching points of the invention.

Returning now to FIG. 1A, transducer 32 receives a control signal 36 and generates an acoustic wave 38 that propagates through crystal member 34 of AOD 30. Control signal 36 preferably is an RF signal provided by an RF modulator 40, preferably driven by a direct digital synthesizer (DDS) 42, or other suitable signal generator, for example a voltage controlled oscillator (VCO). A system controller 44, in operative communication with DDS 42 and a laser driver (not shown), is provided to coordinate between generation of the control signal 36 and laser pulses 24 defining pulsed laser beam 22 so that portions of substrate 14 are removed, e.g. by ablation, in accordance with a desired design pattern of an electrical circuit to be manufactured. Such design pattern may be provided, for example, by a CAD or CAM (computer aided design or computer aided manufacture) data file 46 or other suitable computer file representation of an electrical circuit to be manufactured.

In some applications, pulsed laser beam 24 is delivered to substrate 14 to heat portions of the substrate without ablation, for example for use in laser assisted annealing of amorphous silicon or laser assisted ion implantation in thin film transistors, for