Laser processing device, method of operating same, and method of using same to process a workpiece

Abstract

To provide new functionality by improving a device and a technique for applying laser processing to a workpiece.SOLUTION: The invention relates to the use of a beam property evaluation tool for promoting adaptive processing, process control and other desirable characteristics. Other embodiments are related to laser power sensors incorporating an integrating sphere. Additionally, the other embodiments are related to a workpiece handling system capable of supplying different workpieces simultaneously to a common laser processing device. A number of the other embodiments and configurations are described in detail.SELECTED DRAWING: Figure 1

Description

Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 680,856, filed June 5, 2018, and U.S. Provisional Patent Application No. 62 / 688,484, filed June 22, 2018, each of which is incorporated by reference in its entirety.

[0002] I.Technical field The embodiments disclosed herein relate generally to apparatus for laser processing a workpiece, and more particularly to a laser processing apparatus incorporating a beam characterization tool, a method for operating the same, and a method for laser processing a workpiece using the same.

[0003] II. Background When laser machining a workpiece, knowing the focused size and shape of the laser energy beam incident on the workpiece is critical for calculating the fluence (i.e., energy per unit area) and defining a robust process. As used herein, a process is "robust" if it can meet desired quality specifications not only to small variations in equipment and workpiece characteristics due to environmental changes, handling, and contamination over time, but also to design tolerances in the characteristics of the laser machining equipment.

[0004] The focused laser spot size and shape are generally well-defined immediately after the optical components in the laser processing machine are initially installed and properly aligned. However, the laser spot size and shape at the workpiece can change if an out-of-focus laser spot is used during processing and / or after the laser and laser processing machine are subjected to sudden changes over time, temperature changes, mechanical vibrations and stresses, and optical contamination. For example, when an out-of-focus laser spot is used, the effective spot size varies more than when a focused laser spot is used, due to natural astigmatism in the laser, primarily occurring at the beam "waist." Furthermore, over the lifetime of the laser, the laser spot power may degrade, which can cause undesirable changes in spot size and shape at the workpiece. Second, because laser systems with optical beam delivery systems are subject to temperature changes and mechanical vibrations and stresses, the optical components and optical mounts within the laser processing machine and the laser itself may shift slightly, resulting in changes in spot size at the workpiece. Finally, optical components can become contaminated by debris, dust, oil, and other environmental contaminants, which can distort the beam along its path within the system, causing variations in spot size and spot shape at the workpiece.

[0005] Conventional approaches for monitoring laser spot size and shape and reducing or compensating for changes therein involve one or more of: monitoring and controlling laser power to adjust the fluence (energy / unit area) of the laser pulse irradiated on the workpiece to compensate for spot size changes; using a laser known to have stable pulse energy to ensure pulse energy consistency; using a stable laser known to have low variability in beam size / shape; using a robust optical design to reduce variability in spot size / shape; using a robust mechanical design to avoid environmentally induced beam quality changes caused by misalignment of optical components; robust alignment of optical components during setup or installation of the laser processing machine so that spot size is sufficiently consistent between laser processing machines; and developing laser processing recipes that are more robust and can provide acceptable quality despite a range of spot characteristics, power changes, and beam positioning changes (typically, there is a limit to the degree of robustness that can be achieved for a process recipe; there is generally a trade-off between process robustness and process productivity; as a process becomes more robust, process speed / productivity typically decreases).

[0006] Systems or apparatus for laser processing relatively thin, flexible workpieces (also known as "webs") sometimes include or are used in conjunction with a handling system adapted to guide the web into the laser processing apparatus (e.g., so that the web can be laser processed) and remove the laser-processed web from the apparatus. However, conventional handling systems are known to be capable of handling only one type of web material at a time. Furthermore, conventional laser processing apparatuses typically secure the web in a chuck or other fixture prior to laser processing and then move the fixture (thereby moving the web) during laser processing. Accordingly, some conventional handling systems are known to incorporate dancer roller assemblies that can take up (or add) slack in the web as the fixture moves. However, there can be a delay between the movement of the fixture and the movement of the rollers in the dancer assembly, which can create undesirable tension or strain in the web and potentially damage the web. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a laser processing device according to one embodiment. [Figure 2-3] 2 and 3 are schematic diagrams illustrating the operation of a third positioner 110 equipped with a beam characterization tool for measuring beam properties in one embodiment. [Figure 4] FIG. 4 is a schematic diagram of the beam characterization tool shown in FIGS. 2 and 3 in one embodiment. [Figure 5] FIG. 5 is a schematic diagram illustrating an arrangement of targets on a substrate of the beam characterization tool shown in FIG. 4 in another embodiment. [Figure 6] FIG. 6 is a schematic diagram of another embodiment of the beam characterization tool shown in FIGS. 2 and 3. In FIG. [Figure 7]FIG. 7 is a schematic diagram showing a laser processing device incorporating a laser sensor system according to one embodiment. [Figure 8] FIG. 8 is a schematic diagram of a workpiece handling system in one embodiment. [Figure 9] FIG. 9 is a schematic diagram of a dancer assembly of the workpiece handling system shown in FIG. 8 in one embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a dancer assembly according to another embodiment. [Figure 11] FIG. 11 is a schematic diagram of an unwind assembly of a workpiece handling system in accordance with another embodiment. [Figure 12-13] 12 and 13 are schematic plan views taken along lines XII-XII' and XIII-XIII' shown in FIGS. 11 and 12, respectively. [Figure 14] FIG. 14 is a schematic diagram showing the arrangement of process spots irradiated by laser pulses propagated to a workpiece at a constant pulse repetition rate after the laser pulses are deflected by a resonant scanning mirror system. [Figure 15] FIG. 15 is a schematic diagram illustrating the arrangement of process spots irradiated by laser pulses propagated to a workpiece at a constant pulse repetition rate in one embodiment after the laser pulses are deflected by a resonant scanning mirror system and another positioner configured to compensate for sinusoidal vibrations of the resonant scanning mirror system. [Figure 16-19] 16 to 19 are schematic diagrams showing examples of scan patterns for forming features. overview

[0008] In one embodiment, a laser processing apparatus used in processing a workpiece includes a laser source capable of generating a laser energy beam propagating along a beam path; an AOD system disposed within the beam path and capable of deflecting the beam path through which the laser energy beam may propagate; a beam splitter disposed optically downstream of the AOD system and configured to reflect a first portion of the laser energy beam propagating along the beam path from the AOD system and transmit a second portion of the laser energy beam propagating along the beam path from the AOD system, wherein the first portion of the laser energy beam propagates along the first path and the second portion of the laser energy beam propagates along a second path; and a laser sensor system disposed within the second path and configured to measure laser energy propagating along the second path.

[0009] In another embodiment, a laser processing apparatus for use in processing a workpiece includes a laser source capable of generating a laser energy beam propagated along a beam path, a scan lens disposed in the beam path and capable of focusing the laser energy beam, a positioner capable of supporting the workpiece, and a beam characterization tool coupled to the positioner. The beam characterization tool may include a token having a plurality of targets disposed on a substrate, the targets being formed of a material that is opaque to the laser energy beam and the substrate being formed of a material that is more transparent to the laser energy beam than the targets, a photodetector disposed optically downstream from the token, and an optical filter disposed between the token and the photodetector, the optical filter configured to attenuate laser energy transmitted through the substrate so that the laser energy beam transmitted through the optical filter irradiates the photodetector at a fluence that is lower than a threshold fluence that would damage the photodetector. The positioner is capable of positioning the beam characterization tool within a scan field projected by the scan lens.

[0010] In another embodiment, a laser processing apparatus for use in processing a workpiece includes a laser source capable of generating a laser energy beam propagated along a beam path, a scan lens disposed in the beam path and capable of focusing the laser energy beam, a positioner capable of supporting the workpiece, and a beam characterization tool coupled to the positioner. The beam characterization tool may include a token having a plurality of targets disposed on a substrate, the targets being formed of a material that is opaque to the laser energy beam and the substrate being formed of a material that is more transparent to the laser energy beam than the targets, a photodetector disposed optically downstream from the token, and an optical filter disposed between the token and the photodetector, the optical filter configured to attenuate laser energy transmitted through the substrate so that the laser energy beam transmitted through the optical filter irradiates the photodetector at a fluence that is lower than a threshold fluence that would damage the photodetector. The positioner is capable of positioning the beam characterization tool within a scan field projected by the scan lens.

[0011] In another embodiment, a system for use in processing a workpiece provided as a web material includes a laser processing apparatus and a workpiece handling system. The laser processing apparatus includes a laser source capable of generating a beam of laser energy propagating along a beam path and a fixture capable of securing the workpiece in a position intersecting the beam path, the fixture being movable along a first direction. The workpiece handling system includes an unwind spindle capable of supporting a material roll comprising the workpiece and capable of supplying the workpiece to the laser processing apparatus, a rewind material roll capable of supporting a material roll comprising the workpiece and capable of receiving the workpiece from the laser processing apparatus, and a dancer assembly including a movable frame and a dancer roller coupled to the frame. The dancer assembly is positioned such that a second portion of the workpiece is partially wrapped around the dancer roller when a first portion of the workpiece is secured in the fixture. The frame is movable relative to at least one selected from the group consisting of the unwind spindle and the rewind spindle, and the dancer roller is movable relative to the frame.

[0012] In another embodiment, a system for use in processing workpieces, each provided as a web material, includes a laser processing apparatus and a workpiece handling system. The laser processing apparatus includes a laser source capable of generating a beam of laser energy propagating along a beam path through a process region, the process region being sized to accommodate multiple workpieces simultaneously. The workpiece handling system includes a first spindle capable of feeding a first workpiece to the laser processing apparatus or receiving the first workpiece from the laser processing apparatus, and a second spindle capable of feeding a second workpiece to the laser processing apparatus or receiving the second workpiece from the laser processing apparatus.

[0013] In another embodiment, a laser processing apparatus includes a laser source capable of generating a laser energy beam propagated along a beam path; at least one component capable of performing at least one operation on the laser energy beam selected from the group consisting of (a) deflecting the laser energy beam, (b) adjusting a beam waist position of the laser energy beam along the beam path, (c) adjusting a power of the laser energy beam, and (d) adjusting a beam size of a laser energy beam scan lens; a beam characterization tool capable of measuring one or more characteristics of the laser energy beam and generating measurement data representative of one or more of the measured beam characteristics; and at least one processor. The at least one processor is capable of processing the measurement data to obtain one or more measurements associated with the one or more measured characteristics of the laser energy beam and outputting one or more control signals to the at least one component if the one or more measurements are outside of a threshold processing tolerance. The one or more control signals are configured to cause the at least one component to perform at least one operation on the laser energy beam such that the one or more measured characteristics of the laser energy beam are within the threshold processing tolerance.

[0014] In another embodiment, a laser processing apparatus includes a laser source capable of generating a laser energy beam propagated along a beam path, at least one component capable of performing at least one operation on the laser energy beam selected from the group consisting of (a) deflecting the laser energy beam, (b) adjusting a beam waist position of the laser energy beam along the beam path, (c) adjusting a power of the laser energy beam, and (d) adjusting a beam size of a laser energy beam scan lens, a beam characterization tool capable of measuring one or more spatial characteristics and one or more energy characteristics of the laser energy beam and generating measurement data representing one or more of the measured characteristics, and at least one processor, the one or more processors capable of processing the measurement data to obtain one or more measurements associated with the one or more measured spatial characteristics and the one or more measured energy characteristics of the laser energy beam, and outputting one or more control signals to the at least one component when the one or more measurements associated with the one or more measured spatial characteristics are outside a first threshold processing tolerance and when the one or more measured energy characteristics are outside a second threshold processing tolerance. The one or more control signals are configured to cause the at least one component to perform at least one operation on the laser energy beam such that the one or more measured energy characteristics of the laser energy beam are within the second threshold processing tolerance.

[0015] In another embodiment, a laser processing apparatus for processing a workpiece includes a laser source capable of generating a laser energy beam propagated along a beam path, at least one positioner capable of causing relative movement between the beam path and the workpiece, a beam characterization tool capable of measuring one or more spatial properties of the laser energy beam and generating measurement data representative of one or more of the measured properties, and at least one processor. The at least one processor is capable of processing the measurement data to obtain one or more measurements associated with the one or more measured spatial properties of the laser energy beam, and outputting one or more control signals to the at least one component if the one or more measurements associated with the one or more measured spatial properties are outside a threshold processing tolerance. The one or more control signals are configured to cause the at least one positioner to modify a trajectory along which a process spot illuminated by the laser energy beam is scanned while causing relative movement between the beam path and the workpiece by the at least one positioner.

[0016] In another embodiment, a beam positioning system includes an acousto-optic deflector (AOD) positioned and configured to deflect a laser energy beam along an axis, a resonant scanning mirror system positioned and configured to, when deflected by the AOD, deflect the laser energy beam sinusoidally as a function of time along the axis, and a controller configured to control operation of the AOD such that the laser energy beam, which is in turn deflectable by the AOD and the resonant scanning mirror, is non-sinusoidally deflectable as a function of time.

[0017] Examples of embodiments are described herein with reference to the accompanying drawings. Unless expressly stated otherwise, in the drawings, the sizes, locations, etc. of components, features, elements, etc., as well as distances therebetween, are not necessarily to scale and have been exaggerated for clarity. Like numbers refer to like elements throughout the drawings. Thus, the same or similar numbers may be described with reference to other drawings even if not mentioned or described in the corresponding drawing. Also, elements without reference numbers may be described with reference to other drawings.

[0018] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. As used herein, the singular is intended to include the plural unless the content clearly dictates otherwise. Furthermore, it should be understood that the terms "comprises" and / or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless otherwise indicated, when a range of values ​​is recited, the range includes the upper and lower limits, as well as any subranges between the upper and lower limits of the range. Unless otherwise indicated, terms such as "first" and "second" are used merely to distinguish elements from one another. For example, one node can be referred to as a "first node," and similarly, another node can be referred to as a "second node," or vice versa.

[0019] Unless otherwise indicated, terms such as "about" and "around" mean that amounts, sizes, compositions, parameters, and other quantities and characteristics are not, and need not be, exact, but may be approximate and / or larger or smaller, as appropriate, or to reflect tolerances, conversion factors, rounding, measurement error, and the like, as well as other factors known to those of ordinary skill in the art. Spatially relative terms such as "below," "down," "lower," "upper," and "above" may be used herein for ease of description when describing the relationship of an element or feature to another element or feature, as depicted in the figures. It should be understood that spatially relative terms are intended to encompass different orientations in addition to those depicted in the figures. For example, an element described as being "below" or "below" another element or feature would be oriented "above" that other element or feature if the object in the figure were inverted. Thus, the exemplary term "below" can encompass both an orientation of above and below. If the object is oriented in other ways (e.g., rotated 90 degrees or at other orientations), the spatially relative descriptors used herein may be interpreted accordingly.

[0020] The section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described. It will be understood that many different forms, embodiments, and combinations are possible without departing from the spirit and teachings of the present disclosure, and that the disclosure should not be construed as limited to the example embodiments set forth herein. Rather, these examples and embodiments are provided so that this disclosure will be complete and all-inclusive, and will fully convey the scope of the disclosure to those skilled in the art.

[0021] I. Overview Embodiments described herein generally relate to methods and apparatus for laser processing (or, more simply, "processing") a workpiece. Generally, processing is accomplished in whole or in part by irradiating the workpiece with laser radiation to heat, melt, vaporize, ablate, crack, bleach, polish, roughen, carbonize, foam, or otherwise change one or more characteristics or properties (e.g., chemical composition, atomic structure, ionic structure, molecular structure, electronic structure, microstructure, nanostructure, concentration, viscosity, refractive index, magnetic permeability, dielectric constant, texture, color, hardness, transmissivity to electromagnetic radiation, etc., or any combination thereof) of one or more materials forming the workpiece. The material being processed may be external to the workpiece before or during processing, or may be entirely internal to the workpiece (i.e., not external to the workpiece) before or during processing.

[0022] Specific examples of processes that may be performed by the illustrated laser processing apparatus include via drilling or other hole formation, cutting, punching, welding, scribing, engraving, marking (e.g., surface marking, subsurface marking, etc.), laser-induced forward transfer, cleaning, bleaching, bright pixel repair (e.g., color filter darkening, OLED material modification, etc.), film removal, surface texturing (e.g., roughening, smoothing, etc.), or the like, or any combination thereof. Thus, one or more features that may be formed on or in a workpiece as a result of processing may include openings, slots, vias or other holes, grooves, trenches, scribe lines, kerfs, recesses, traces, ohmic contacts, resistor patterns, human-readable or machine-readable indicia (e.g., comprising one or more areas in or on the workpiece having one or more visually or texturally distinguishable characteristics), or the like, or any combination thereof. Apertures, slots, vias, holes, and other features may have any suitable or desirable shape when viewed in a top view (e.g., circular, oval, square, rectangular, triangular, annular, or the like, or any combination thereof). Furthermore, apertures, slots, vias, holes, and other features may extend completely through the workpiece (e.g., to form so-called "through vias," "through holes," etc.) or may extend only partially through the workpiece (e.g., to form so-called "blind vias," "blind holes," etc.).

[0023] A work piece that can be processed is comprehensively characterized as being formed from one or more metals, polymers, ceramics, composites, or any arbitrary combination thereof (regardless of whether it is an alloy, a compound, a mixture, a solution, a composite, etc.). Thus, the materials that can be processed include one or more metals such as Al, Ag, Au, Cr, Cu, Fe, In, Mg, Mo, Ni, Pt, Sn, Ti, etc., or any arbitrary combination thereof (regardless of whether it is an alloy, a composite, etc.), conductive metal oxides (such as ITO, etc.), transparent conductive polymers, ceramics, waxes, resins, interlayer dielectric materials (such as silicon oxide, silicon nitride, silicon oxynitride, etc., low-k dielectric materials such as methylsilsesquioxane (MSQ), hydrogen silsesquioxane (HSQ), tetraethyl orthosilicate fluoride (FTEOS), etc., or any arbitrary combination thereof), organic dielectric materials (such as SILK, benzocyclobutene, Nautilus (all manufactured by Dow), polytetrafluoroethylene (manufactured by DuPont), FLARE (manufactured by Allied Chemical), etc., or any arbitrary combination thereof), electronic or optical device substrate materials (such as Al2O3, AlN, BeO, Cu, GaAS, GaN, Ge, InP, Si, SiO2, SiC, Si 1-x Ge x (0.0001 < x < 0.9999), etc., or any arbitrary combination thereof or its alloy), glass (such as fused quartz, soda-lime glass, sodium borosilicate glass, lead oxide glass, aluminosilicate glass, germanium oxide glass, aluminate glass, phosphate glass, borate glass, chalcogenide glass, amorphous metal, etc., or any arbitrary combination thereof), leather, paper, assembly materials (such as the Ajinomoto build-up film also known as "ABF"), solder resist, etc., or any arbitrary composite, laminate, or other combination thereof.

[0024] Specific examples of workpieces that may be processed include printed circuit board (PCB) panels (also referred to herein as "PCB panels"), PCBs, PCB laminates (e.g., FR4, high Tg epoxy, BT, polyimide, etc., or any combination thereof), PCB laminate prepregs, substrate-like PCBs (SLPs), flexible printed circuit (FPC) panels (also referred to herein as "FPC panels"), FPCs, coverlay films, integrated circuits (ICs), IC substrates, IC packages (ICPs), light emitting diodes (LEDs), LED packages, semiconductor wafers, electronic or optical device substrates, interposers, lead frames, lead frame blanks, display substrates (e.g., TFTs, color filters, , organic light emitting diode (OLED) arrays, quantum dot LED arrays, etc., or any combination thereof), lenses, mirrors, turbine blades, powders, films, foils, plates, molds (e.g., wax molds, molds for injection molding or investment casting processes, etc.), textiles (woven fabrics, felt, etc.), surgical instruments, medical implants, packaged products, shoes, bicycles, automobiles, automobile or aviation parts (e.g., frames, body panels, etc.), appliances (e.g., microwave ovens, ovens, refrigerators, etc.), device housings (e.g., for watches, computers, smartphones, tablet computers, wearable electronic devices, etc., or any combination thereof).

[0025] II. System Overview FIG. 1 is a schematic diagram of a laser processing device according to one embodiment of the present invention.

[0026] Referring to the embodiment shown in FIG. 1 , a laser processing apparatus 100 (also referred to herein simply as “apparatus”) for processing a workpiece 102 can be characterized as including a laser source 104 for generating a beam of laser energy, one or more positioners (e.g., a first positioner 106, a second positioner 108, a third positioner 110, or any combination thereof), and a scan lens 112.

[0027] Laser energy passing through the scan lens 112 and propagating along the beam path 116 propagates along a beam axis 118 to impinge on the workpiece 102. The laser energy propagating along the beam axis 118 may be characterized as having a Gaussian spatial intensity profile or a non-Gaussian (i.e., "shaped") spatial intensity profile (e.g., a "top hat" spatial intensity profile). Regardless of the type of spatial intensity profile, the spatial intensity profile may also be characterized as the shape (i.e., cross-sectional shape, also referred to herein as "spot shape") of the laser energy beam propagating along the beam axis 118 (or beam path 116), which may be circular, elliptical, square, rectangular, triangular, hexagonal, ring-shaped, etc., or any other shape. As used herein, the term "spot size" refers to the diameter or maximum spatial width of the laser energy beam impinging on a location where the beam axis 118 intersects with an area of ​​the workpiece 102 that is at least partially processed by the impinging laser energy beam (also referred to as a "process spot," "spot location," or more simply "spot"). For purposes of discussion herein, spot size refers to a spot size that is measured from the beam axis 118 such that the optical intensity is at least 1 / e of the optical intensity at the beam axis 118. 2The spot size of the laser energy beam is measured as the radial or transverse distance down to the beam waist. Generally, the spot size of the laser energy beam is smallest at the beam waist. When irradiated onto the workpiece 102, the laser energy in the beam can be characterized as striking the workpiece 102 with a spot size ranging from 2 μm to 200 μm. However, it will be understood that the spot size can be less than 2 μm or greater than 200 μm. Thus, the laser energy beam irradiated onto the workpiece 102 can have a spot size greater than, less than, or equal to 2 μm, 3 μm, 5 μm, 7 μm, 10 μm, 15 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 80 μm, 100 μm, 150 μm, 200 μm, etc., or a spot size between any of these values.

[0028] Generally, the positioners described above (e.g., first positioner 106, second positioner 108, and third positioner 110) are configured to vary the relative position between the spot and workpiece 102. In consideration of the following description, it should be understood that if the apparatus 100 includes the second positioner 108, the third positioner 110, or a combination thereof, the inclusion of the first positioner 106 is optional (i.e., the apparatus 100 need not include the first positioner 106). Similarly, it should be understood that if the apparatus 100 includes the first positioner 106, the third positioner 110, or a combination thereof, the inclusion of the second positioner 108 is optional. Finally, it should be understood that if the apparatus 100 includes the first positioner 106, the second positioner 108, or a combination thereof, the inclusion of the third positioner 110 is optional.

[0029] The apparatus 100 also includes one or more optical elements (e.g., beam expanders, beam shapers, apertures, filters, collimators, lenses, mirrors, polarizers, wave plates, diffractive optical elements, refractive optical elements, etc., or any combination thereof) to focus, expand, collimate, shape, polarize, filter, split, combine, crop, or otherwise modify, condition, direct, or otherwise shape the beam of laser energy resulting from the laser source 104 along one or more beam paths (e.g., beam path 116) to the scan lens 112. Such optical elements may be inserted at any suitable or desired location in the beam path 116 (e.g., between the laser source 104 and the first positioner 106, between the laser source 104 and the second positioner 108, between the first positioner 106 and the second positioner 108, between the second positioner 108 and the scan lens 112, or similar locations, or any combination thereof).

[0030] One example of such an optical element is a variable optical attenuator (VOA) configured to selectively and variably reduce the power of laser pulses propagating along beam path 116. Examples of VOA's that may be incorporated include one or more systems such as variable neutral density filters, acousto-optic (AO) modulators (AOM's), AO deflectors (AOD's), liquid crystal variable attenuators (LCVA's), microelectromechanical system (MEMS) based VOA's, optical attenuator wheels, polarization / waveplate filters, and the like, or any combination thereof.

[0031] Another example of such an optical element is a beam size adjustment mechanism that can selectively and variably adjust the size of the laser energy beam (also referred to herein as "beam size") incident on the scan lens 112. As used herein, the term "beam size" refers to the diameter or width of the laser energy beam, and refers to the distance from the beam axis 118 where the optical intensity is 1 / e of the optical intensity at the axis of propagation along the beam path 116. 2The beam size may be measured as a radial or transverse distance down to a point where the beam size drops ...

[0032] Another example of such an optical element is the shape of the laser energy beam (referred to herein as the "beam") incident on the scan lens 112. shape " is a selectively and variably adjustable beam shaping mechanism. Examples of beam shaping mechanisms that can be incorporated include an AOD, a deformable mirror, a variable radius mirror, a variable focus moiré lens, and the like, or any combination thereof. By adjusting the beam shape of the laser energy beam incident on the scan lens 112, the spot shape at the workpiece 102 can be changed.

[0033] A. Laser Source In one embodiment, the laser source 104 is capable of generating laser pulses. As such, the laser source 104 may include a pulsed laser source, a CW laser source, a QCW laser source, a burst-mode laser, or the like, or any combination thereof. If the laser source 104 includes a QCW laser source or a CW laser source, the laser source 104 may further include a pulse gating unit (e.g., an acousto-optic (AO) modulator (AOM), a beam chopper, or the like) that temporally modulates the beam of laser radiation output from the QCW laser source or the CW laser source. Although not shown, the apparatus 100 may optionally include one or more harmonic generation crystals (also known as “wavelength conversion crystals”) configured to convert the wavelength of the light output by the laser source 104. However, in other embodiments, the laser source 104 may be provided as a QCW laser source or a CW laser source and may not include a pulse gating unit. As such, laser source 104 can be broadly characterized as being capable of generating a laser energy beam that may be expressed as a series of laser pulses or as a continuous or quasi-continuous laser beam, which may then propagate along beam path 116. While many of the embodiments described herein refer to laser pulses, it should be understood that a continuous beam may be used instead or in addition, where appropriate.

[0034] Laser light having an electromagnetic spectrum in the UV range may have one or more wavelengths in the range of 10 nm (or thereabouts) to 385 nm (or thereabouts), such as 10 nm, 121 nm, 124 nm, 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, etc., or wavelengths between any of these values. Laser light having an electromagnetic spectrum in the visible green range may have one or more wavelengths in the range of 500 nm (or thereabouts) to 560 nm (or thereabouts), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, etc., or wavelengths between any of these values. Laser light having an IR range of the electromagnetic spectrum may have one or more wavelengths in the range of 750 nm (or thereabouts) to 15 μm (or thereabouts), such as 600 nm to 1000 nm, 752.5 nm, 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm, 1053 nm, 1060 nm, 1064 nm, 1080 nm, 1090 nm, 1152 nm, 1150 nm to 1350 nm, 1540 nm, 2.6 μm to 4 μm, 4.8 μm to 8.3 μm, 9.4 μm, 10.6 μm, etc., or wavelengths between any of these values.

[0035] The laser pulses output by the laser source 104 may have a pulse width or duration (i.e., based on the full width at half maximum (FWHM) of the optical power in the pulse with respect to time) ranging from 10 fs to 900 ms, although it will be understood that the pulse duration may be shorter than 10 fs or longer than 900 ms. Thus, the at least one laser pulse output by the laser source 104 may be 10 fs, 15 fs, 30 fs, 50 fs, 100 fs, 150 fs, 200 fs, 300 fs, 500 fs, 600 fs, 750 fs, 800 fs, 850 fs, 900 fs, 950 fs, 1 ps, 2 ps, 3 ps, 4 ps, 5 ps, 7 ps, 10 ps, ​​15 ps, 25 ps, 50 ps, ​​75 ps, 100 ps, ​​200 ps, ​​500 ps, ​​1 ns, 1.5 ns, 2 ns, 5 ns, 10 ns, 2 The pulse duration may be shorter than, longer than, or equal to 0 ns, 50 ns, 100 ns, 200 ns, 400 ns, 800 ns, 1000 ns, 2 μs, 5 μs, 10 μs, 50 μs, 100 μs, 300 μs, 500 μs, 900 μs, 1 ms, 2 ms, 5 ms, 10 ms, 20 ms, 50 ms, 100 ms, 300 ms, 500 ms, 900 ms, 1 s, etc., or any value between these values.

[0036] The laser pulses output by the laser source 104 can have an average power ranging from 5 mW to 50 kW. However, it will be understood that the average power can be less than 5 mW or greater than 50 kW. Thus, the laser pulses output by the laser source 104 can have an average power less than, greater than, or equal to 5 mW, 10 mW, 15 mW, 20 mW, 25 mW, 50 mW, 75 mW, 100 mW, 300 mW, 500 mW, 800 mW, 1 W, 2 W, 3 W, 4 W, 5 W, 6 W, 7 W, 10 W, 15 W, 18 W, 25 W, 30 W, 50 W, 60 W, 100 W, 150 W, 200 W, 250 W, 500 W, 2 kW, 3 kW, 20 kW, 50 kW, etc., or any value between these values.

[0037] Laser source 104 can output laser pulses at a pulse repetition rate ranging from 5 kHz to 1 GHz. However, it will be appreciated that the pulse repetition rate can be less than 5 kHz or greater than 1 GHz. Thus, laser source 104 can output laser pulses at pulse repetition rates less than, greater than, or equal to 5 kHz, 50 kHz, 100 kHz, 175 kHz, 225 kHz, 250 kHz, 275 kHz, 500 kHz, 800 kHz, 900 kHz, 1 MHz, 1.5 MHz, 1.8 MHz, 1.9 MHz, 2 MHz, 2.5 MHz, 3 MHz, 4 MHz, 5 MHz, 10 MHz, 20 MHz, 50 MHz, 60 MHz, 100 MHz, 150 MHz, 200 MHz, 250 MHz, 300 MHz, 350 MHz, 500 MHz, 550 MHz, 600 MHz, 900 MHz, 2 GHz, 10 GHz, etc., or any value between these values.

[0038] In addition to wavelength, pulse duration, average power, and pulse repetition rate, the laser pulses irradiating the workpiece 102 may be characterized by one or more other properties, such as pulse energy, peak power, etc. The laser pulses may be of sufficient power (W / cm) to process the workpiece 102 (e.g., to form one or more features having one or more desired properties). 2 Light intensity (measured in J / cm 2 The laser beam can be selected (e.g., based on one or more other characteristics, such as wavelength, pulse duration, average power, and pulse repetition rate, as needed) to irradiate the workpiece 102 at the process spot with a fluence, such as measured by the laser beam intensity (measured in Hz).

[0039] Examples of types of lasers that may characterize laser source 104 include gas lasers (e.g., carbon dioxide lasers, carbon monoxide lasers, excimer lasers, etc.), solid-state lasers (e.g., Nd:YAG lasers, etc.), rod lasers, fiber lasers, photonic crystal rod / fiber lasers, passively modelocked solid-state bulk or fiber lasers, dye lasers, modelocked diode lasers, pulsed lasers (e.g., ms pulsed lasers, ns pulsed lasers, ps pulsed lasers, fs pulsed lasers), CW lasers, quasi-CW lasers, etc., or any combination thereof. In some configurations, gas lasers (e.g., carbon dioxide lasers, etc.) may be configured to operate in one or more modes (e.g., CW mode, quasi-CW mode, pulsed mode, or any combination thereof). Specific examples of laser sources that can be provided as laser source 104 include BOREAS, HEGOA, SIROCCO, or CHINOOK series lasers manufactured by EOLITE, PYROFLEX series lasers manufactured by PYROPHOTONICS, PALADIN Advanced 355, DIAMOND series (e.g., DIAMOND E, G, J-2, J-3, J-5 series), FLARE NX, MATRIX QS DPSS, MEPHISTO Q, AVIA LX, AVIA NX, RAPID NX, HYPERRAPID NX, RAPID, HELIOS, FIDELITY, MONACO, OPERA, or RAPID FX series lasers manufactured by COHERENT, PALADIN Advanced 355, DIAMOND series (e.g., DIAMOND E, G, J-2, J-3, J-5 series), ASCEND, EXCELSIOR, EXPLORER, HIPPO, NAVIGATOR, QUATA-RAY, QUASAR, SPIRIT, TALON, or VGEN series lasers, PULSTAR series or FIRESTAR series lasers manufactured by SYNRAD, TRUFLOW series lasers manufactured by TRUMPF (e.g., TRUFLOW2000, 1700, 3000, 3200, 3600, 4000, 5000, 6000, 6000, 8000, 10000, 12000, 15000, 20000), TRUCOAX series lasers (e.g., TRUCOAX 1000) or TRUDISK, TRUPULSE, TRUDIODE, TRUFIBER, or TRUMICRO series lasers, FCPA μJEWEL or FEMTOLITE series lasers manufactured by IMRA AMERICA, TANGERINE and SATSUMA series lasers (and MIKAN and T-PULSE series oscillators) manufactured by AMPLITUDE SYSTEMES, IPG and one or more laser sources such as the CL, CLPF, CLPN, CLPNT, CLT, ELM, ELPF, ELPN, ELPP, ELR, ELS, FLPN, FLPNT, FLT, GLPF, GLPN, GLR, HLPN, HLPP, RFL, TLM, TLPN, TLR, ULPN, ULR, VLM, VLPN, YLM, YLPF, YLPN, YLPP, YLR, YLS, FLPM, FLPMT, DLM, BLM, or DLR series lasers manufactured by PHOTONICS, Inc. (including, for example, GPLN-100-M, GPLN-500-QCW, GPLN-500-M, GPLN-500-R, GPLN-2000-S, etc.), or the like, or any combination thereof.

[0040] B. First positioner The first positioner 106 is disposed, positioned, or installed in the beam path 116 and is operable to diffract, reflect, refract, or the like, or any combination thereof, the laser pulses generated by the laser source 104 (i.e., to "deflect" the laser pulses) to deflect or move the beam path 116 (e.g., relative to the scan lens 112) and thereby deflect or move the beam axis 118 relative to the workpiece 102. Generally, the first positioner 106 is operable to move the beam axis 118 relative to the workpiece 102 along an X-axis (or X-direction), a Y-axis (or Y-direction), or a combination thereof. Although not shown, the X-axis (or X-direction) should be understood to mean an axis (or direction) that is orthogonal to the illustrated Y-axis (or Y-direction) and Z-axis (or Z-direction).

[0041] The movement of the beam axis 118 relative to the workpiece 102 by the first positioner 106 is generally limited to scanning, moving or positioning the process spot within a first scan field or “first scanning range” projected by the scan lens 112. In general, depending on one or more factors such as the configuration of the first positioner 106, the location of the first positioner 106 along the beam path 116, the beam size of the laser pulse incident on the first positioner 106, the spot size, etc., the first scanning range may extend in either the X or Y direction by a distance less than, greater than, or equal to 0.01 mm, 0.04 mm, 0.1 mm, 0.5 mm, 1.0 mm, 1.4 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.2 mm, 5 mm, 10 mm, 25 mm, 50 mm, 60 mm, etc., or any value between these values. The maximum dimension of the first scanning range (e.g., in the X or Y direction, or other direction) may be greater than, equal to, or less than the maximum dimension (measured in the XY plane) of a feature (e.g., opening, recess, via, trench, etc.) to be formed in the workpiece 102.

[0042] Typically, the speed at which the first positioner 106 can position the process spot (thereby moving the beam axis 118) anywhere within the first scanning range (also referred to as the "positioning speed") ranges from 8 kHz (or thereabouts) to 250 MHz (or thereabouts). This range is also referred to herein as the first positioning bandwidth. For example, the first positioning bandwidth may be greater than, equal to, or less than 8 kHz, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 75 kHz, 80 kHz, 100 kHz, 250 kHz, 500 kHz, 750 kHz, 1 MHz, 5 MHz, 10 MHz, 20 MHz, 40 MHz, 50 MHz, 75 MHz, 100 MHz, 125 MHz, 150 MHz, 175 MHz, 200 MHz, 225 MHz, 250 MHz, etc., or a value between any of these values. The inverse of the positioning speed is referred to herein as the “positioning time,” which refers to the shortest time required to change the position of a process spot from one position within the first scanning range to any other position within the first scanning range. Thus, the first positioner 106 can be characterized as having a positioning time greater than, equal to, or less than 200 μs, 125 μs, 100 μs, 50 μs, 33 μs, 12.5 μs, 10 μs, 4 μs, 2 μs, 1.3 μs, 1 μs, 0.2 μs, 0.1 μs, 0.05 μs, 0.025 μs, 0.02 μs, 0.013 μs, 0.01 μs, 0.008 μs, 0.0067 μs, 0.0057 μs, 0.0044 μs, 0.004 μs, etc., or a value between any of these values.

[0043] The first positioner 106 may be a microelectromechanical system (MEMS) mirror or mirror array, an AOD system, an electro-optic deflector (EOD) system, a fast steering mirror (FSM) element (e.g., incorporating piezoelectric actuators, electrostrictive actuators, voice coil actuators, etc.), a non-resonant galvanometer mirror system, a resonant scanning galvanometer mirror system, a rotary polygon scanner, or the like, or any combination thereof. For purposes of discussion herein, a resonant scanning galvanometer mirror system is referred to as a “resonant scanning mirror system,” and a non-resonant galvanometer mirror system is referred to as a “galvanometer mirror system.” Galvanometer mirror systems typically provide full positioning control while typically offering a narrower positioning bandwidth (e.g., 1 kHz to 3 kHz, or thereabouts) than that of a resonant scanning mirror system (e.g., 4 kHz to 8 kHz, or thereabouts). However, resonant scanning mirror systems typically provide much less positioning control than galvanometer mirror systems, and the scanning provided by resonant scanning mirror systems is nonlinear. Generally, resonant scanning mirror systems provide sinusoidal scanning, such that the position of the process spot from the beam deflected by the resonant scanning mirror system varies sinusoidally as a function of time. Positioners such as AOD and EOD systems typically have positioning speeds that are much greater than the positioning speed of galvanometer mirror systems (whether nonresonant or resonant scanning).

[0044] In one embodiment, the first positioner 106 is an AOD system including at least one (e.g., one, two, three, four, etc.) single-element AOD system, at least one (e.g., one, two, three, four, etc.) phased-array AOD system, etc., or any combination thereof. Single-element and phased-array AOD systems each include an AO cell formed from a material such as crystalline Ge, PbMoO4, or TeO2, glassy SiO2, quartz, or As2S3. As used herein, a "single-element" AOD system refers to an AOD system having only one ultrasonic transducer element acoustically coupled to an AO cell, and a "phased-array" AOD system includes a phased array of at least two ultrasonic transducer elements acoustically coupled to a common AO cell.

[0045] As will be appreciated by those skilled in the art, AO techniques (e.g., AOD, AOM, etc.) utilize diffraction effects caused by acoustic waves propagating through an AO cell to modulate one or more properties of a light wave (i.e., in the context of this application, a laser energy beam) co-propagating through the AO cell. Typically, an AO cell can support both acoustic and optical waves in the same region. The acoustic waves perturb the refractive index within the AO cell. The acoustic waves are typically launched into the AO cell by driving ultrasonic transducer elements at one or more RF frequencies. By controlling the properties of the acoustic waves (e.g., amplitude, frequency, phase, etc.), one or more properties of the propagating optical waves can be controllably modulated to move the beam path 116 (e.g., relative to the scan lens 112). It should also be understood that known techniques for attenuating the energy in a laser energy beam as it passes through the AO cell can be used to control the properties of the acoustic waves launched into the AO cell. Thus, the AOD system may also be operated to modulate the pulse energy (and correspondingly the fluence, peak power, optical intensity, average power, etc.) of the laser pulse that ultimately impinges on the workpiece 102 .

[0046] It will be appreciated that the material from which the AO cell is made will depend on the wavelength of the laser pulses propagating along beam path 116 and incident on the AO cell. For example, if the wavelength of the laser pulses to be deflected is in the range of 2 μm (or thereabouts) to 12 μm (or thereabouts), materials such as crystalline Ge can be used. If the wavelength of the laser pulses to be deflected is in the range of 200 nm (or thereabouts) to 5 μm (or thereabouts), materials such as quartz and TeO2 can be used.

[0047] It should be understood that the AOD system is a dispersive element and, as a result, preferably deflects laser pulses having a suitably narrow spectral linewidth (e.g., based on the full width at half maximum (FWHM) of the optical power spectral density in the pulse). Typically, a laser source 104 capable of generating laser pulses having one or more wavelengths in one or more of the ultraviolet, visible, or NIR ranges generates laser pulses having a suitably narrow spectral linewidth. Laser sources 104 such as high-power CW gas lasers (e.g., carbon dioxide or carbon monoxide CW lasers having average powers greater than about 300 W) and other low-power CW or pulsed gas lasers (e.g., having average powers less than about 300 W) can similarly generate laser pulses having a suitably narrow spectral linewidth in the SWIR, MWIR, or LWIR ranges. Traditionally, high-power pulsed gas lasers capable of generating laser pulses (e.g., carbon dioxide or carbon monoxide pulsed lasers having average powers greater than about 300 W) are based on a master oscillator power amplifier (MOPA) laser system architecture.

[0048] Any of the AOD systems may be provided as a single-axis AOD system (e.g., capable of moving the beam axis along a single direction) or as a multi-axis AOD system (e.g., capable of moving the beam axis 118 along one or more axes, e.g., along the X-axis, along the Y-axis, or a combination thereof) by deflecting the beam path 116. Generally, a multi-axis AOD system may be a multi-cell system or a single-cell system. A multi-cell multi-axis system typically includes multiple AOD systems, each capable of moving the beam axis along a different axis. For example, a multi-cell multi-axis system may include a first AOD system (e.g., an “X-axis AOD system”) capable of moving the beam axis 118 along the X-axis (e.g., a single-element or phased-array AOD system) and a second AOD system (e.g., a “Y-axis AOD system”) capable of moving the beam axis 118 along the Y-axis (e.g., a single-element or phased-array AOD system). A single-cell multi-axis system (e.g., an "X / Y-axis AOD system") typically includes a single AOD system capable of moving the beam axis 118 along the X and Y axes. For example, a single-cell system may include at least two ultrasonic transducer elements acoustically coupled to orthogonal planes, facets, sides, etc. of a common AO cell.

[0049] C. Second positioner The second positioner 108 is disposed in the beam path 116 and is operable to diffract, reflect, refract, or the like, or any combination thereof (i.e., to "deflect" the laser pulses) generated by the laser source 104 and passed through the first positioner 106, to deflect or move the beam path 116 (e.g., relative to the scan lens 112) and consequently, to deflect or move the beam axis 118 relative to the workpiece 102. Generally, the second positioner 108 can move the beam axis 118 relative to the workpiece 102 along the X-axis (or X-direction), the Y-axis (or Y-direction), or a combination thereof.

[0050] Movement of the beam axis 118 relative to the workpiece 102 by the second positioner 108 is generally limited to scanning, moving, or positioning the process spot within a second scan field or "second scanning range" projected by the scan lens 112. Generally, the second scanning range may extend a distance in either the X or Y direction that is greater than the corresponding distance of the first scanning range, depending on one or more factors such as the configuration of the second positioner 108, the location of the second positioner 108 along the beam path 116, the beam size of the laser pulse incident on the second positioner 108, and the spot size. In view of the above, the second scanning range may extend in either the X or Y direction a distance less than, greater than, or equal to 1 mm, 25 mm, 50 mm, 75 mm, 100 mm, 250 mm, 500 mm, 750 mm, 1 cm, 25 cm, 50 cm, 75 cm, 1 m, 1.25 m, 1.5 m, etc., or any value between these values. The maximum dimension of the second scanning range (e.g., in the X or Y direction or other direction) may be greater than, equal to, or less than the maximum dimension (measured in the XY plane) of a feature (e.g., opening, recess, via, trench, scribe line, conductive trace, etc.) to be formed in the workpiece 102.

[0051] It should be understood that in the configurations described herein, the movement of the beam axis 118 performed by the first positioner 106 can be superimposed on the movement of the beam axis 118 performed by the second positioner 108. In this manner, the second positioner 108 is operable to scan the first scanning range within the second scanning range.

[0052] Generally, the positioning speed at which the second positioner 108 can position the process spot anywhere within the second scanning range (thereby moving the beam axis 118 within the second scanning range and / or scanning the first scanning range within the second scanning range) spans a range narrower than the first positioning bandwidth (also referred to herein as the “second positioning bandwidth”). In one embodiment, the second positioning bandwidth ranges from 500 Hz (or thereabouts) to 8 kHz (or thereabouts). For example, the second positioning bandwidth may be greater than, equal to, or less than 500 Hz, 750 Hz, 1 kHz, 1.25 kHz, 1.5 kHz, 1.75 kHz, 2 kHz, 2.5 kHz, 3 kHz, 3.5 kHz, 4 kHz, 4.5 kHz, 5 kHz, 5.5 kHz, 6 kHz, 6.5 kHz, 7 kHz, 7.5 kHz, 8 kHz, etc., or a value between any of these values.

[0053] In view of the above, it should be understood that second positioner 108 can be a microelectromechanical system (MEMS) mirror or mirror array, an AOD system, an electro-optic deflector (EOD) system, a fast steering mirror (FSM) element (e.g., incorporating piezoelectric actuators, electrostrictive actuators, voice coil actuators, etc.), a galvanometer mirror system, a resonant scanning mirror system, a rotary polygon scanner, or the like, or any combination thereof. In one embodiment, second positioner 108 can be a galvanometer mirror system including two galvanometer mirror elements: a first galvanometer mirror element (e.g., an X-axis galvanometer mirror element) configured to move beam axis 118 relative to workpiece 102 along the X-axis, and a second galvanometer mirror element (e.g., a Y-axis galvanometer mirror element) configured to move beam axis 118 relative to workpiece 102 along the Y-axis. However, in other embodiments, the second positioner 108 may be provided as a galvanometer mirror system including a single galvanometer mirror component configured to move the beam axis 118 along the X and Y axes relative to the workpiece 102. In still other embodiments, the second positioner 108 may be provided as a rotating polygon mirror system, or the like. Thus, it will be appreciated that the second positioning bandwidth may be greater than or equal to the first positioning bandwidth, depending on the particular configuration of the second positioner 108 and the first positioner 106.

[0054] D. Third Positioner The third positioner 110 is operable to move the workpiece 102 relative to the scan lens 112, which in turn moves the workpiece 102 relative to the beam axis 118. Movement of the workpiece 102 relative to the beam axis 118 is generally limited to scan, move, or position a process spot within a third scan field or "third scanning range." Depending on one or more factors, such as the configuration of the third positioner 110, the third scanning range may extend in either the X or Y direction to a distance greater than or equal to the corresponding distance of the second scanning range. However, typically, the maximum dimension of the third scanning range (e.g., in the X or Y direction, or other direction) is greater than or equal to the corresponding maximum dimension (measured in the XY plane) of a feature to be formed on the workpiece 102. If desired, the third positioner 110 may be capable of moving the workpiece 102 relative to the beam axis 118 within a scanning range extending in the Z direction (e.g., over a range of 1 mm to 50 mm). Thus, the third scanning range may extend along the X, Y, and / or Z directions.

[0055] It should be understood that in the configurations described herein, movement of the process spot relative to the workpiece 102 (performed by the first positioner 106 and / or the second positioner 108) can be superimposed on movement of the workpiece 102 performed by the third positioner 110. As such, the third positioner 110 is operable to scan the first scanning range and / or the second scanning range within the third scanning range. Generally, the positioning speed at which the third positioner 110 can position the workpiece 102 anywhere within the third scanning range (thereby moving the workpiece 102 to scan the first scanning range within the third scanning range and / or scan the second scanning range within the third scanning range) spans a range narrower than the second positioning bandwidth (also referred to herein as the “third positioning bandwidth”). In one embodiment, the third positioning bandwidth is less than (or equal to) 500 Hz. For example, the third positioning bandwidth can be less than or equal to 500 Hz, 250 Hz, 150 Hz, 100 Hz, 75 Hz, 50 Hz, 25 Hz, 10 Hz, 7.5 Hz, 5 Hz, 2.5 Hz, 2 Hz, 1.5 Hz, 1 Hz, etc., or any value between these values.

[0056] In one embodiment, the third positioner 110 is provided as one or more linear stages (e.g., capable of translating the workpiece 102 along the X, Y, and / or Z directions, respectively), one or more rotary stages (e.g., capable of imparting rotational movement to the workpiece 102 about axes parallel to the X, Y, and / or Z directions, respectively), the like, or any combination thereof. In one embodiment, the third positioner 110 includes an X-axis stage for moving the workpiece 102 along the X direction, and a Y-axis stage supported by (and thereby movable along the X direction by) the X-axis stage for moving the workpiece 102 along the Y direction. Although not shown, the apparatus 100 may include an optional base (e.g., a granite block) for supporting the third positioner 110.

[0057] Although not shown, the apparatus 100 may optionally include a fixture (e.g., a chuck) coupled to a stage of the third positioner 110. The fixture may include a support area within which the workpiece 102 may be mechanically clamped, secured, held, secured, or supported by the fixture. In one embodiment, the workpiece 102 may be clamped, secured, held, secured, or supported in direct contact with a typically flat primary support surface of the fixture. In other embodiments, the workpiece 102 may be clamped, secured, held, secured, or supported away from the support surface of the fixture. In one embodiment, the workpiece 102 may be secured, held, or secured by a force (e.g., electrostatic, vacuum, or magnetic) selectively applied to the workpiece 102 by the fixture or present between the workpiece 102 and the fixture.

[0058] As discussed above, apparatus 100 utilizes a so-called "stacked" positioning system in which the positions of components such as first positioner 106, second positioner 108, and scan lens 112 remain stationary within apparatus 100 relative to workpiece 102 (e.g., via one or more supports, frames, etc., as known in the art), while third positioner 110 moves workpiece 102. In other embodiments, third positioner 110 may be positioned and operable to move one or more components such as first positioner 106, second positioner 108, and scan lens 112, and workpiece 102 may be stationary.

[0059] In yet other embodiments, the third positioner 110 may be provided as a so-called "split-axis" positioning system, in which one or more components, such as the first positioner 106, the second positioner 108, the scan lens 112, etc., or any combination thereof, are carried by one or more linear or rotary stages (mounted on a frame, gantry, etc.), and the workpiece 102 is carried by one or more other linear or rotary stages. In such embodiments, the third positioner 110 includes one or more linear or rotary stages positioned and operable to move one or more components, such as the scan head (e.g., including the second positioner 108 and the scan lens 112), and one or more linear or rotary stages positioned and operable to move the workpiece 102. For example, the third positioner 110 may include a Y-stage for moving the workpiece 102 along the Y-direction and an X-stage for moving the scan head along the X-direction. Examples of split-axis positioning systems that may be beneficially or advantageously employed in apparatus 100 include any of those disclosed in U.S. Patent Nos. 5,751,585, 5,798,927, 5,847,960, 6,606,999, 7,605,343, 8,680,430, 8,847,113, or U.S. Patent Application Publication No. 2014 / 0083983, each of which is incorporated herein by reference in its entirety, or any combination thereof.

[0060] In one embodiment in which the third positioner 110 includes a Z stage, the Z stage may be positioned and configured to move the workpiece 102 along the Z direction. In this case, the Z stage may be carried by, or the Z stage may carry, one or more of the other stages described above for moving or positioning the workpiece 102, or any combination thereof. In other embodiments in which the third positioner 110 includes a Z stage, the Z stage may be positioned and configured to move the scan head along the Z direction. Thus, when the third positioner 110 is provided as a split-axis positioning system, the Z stage may carry or be carried by the X stage. Moving the workpiece 102 or the scan head along the Z direction can change the spot size at the workpiece 102.

[0061] In yet other embodiments, one or more components, such as first positioner 106, second positioner 108, and scan lens 112, may be carried by a multi-axis articulated robot arm (e.g., a two-axis, three-axis, four-axis, five-axis, or six-axis arm). In such embodiments, second positioner 108 and / or scan lens 112 may be carried by an end effector of the robot arm, as needed. In yet other embodiments, workpiece 102 may be carried directly on the end effector of the multi-axis articulated robot arm (i.e., without third positioner 110). In yet other embodiments, third positioner 110 may be carried on the end effector of the multi-axis articulated robot.

[0062] D. Scan lens In general, the scan lens 112 (e.g., provided as either a simple lens or a compound lens) is typically configured to focus laser pulses directed along the beam path to generate a beam waist that may be located at or near a desired process spot. The scan lens 112 may be provided as an f-theta lens, a telecentric lens, an axicon lens (in which case a series of beam waists are generated, resulting in multiple process spots offset from one another along the beam axis 118), or any combination thereof. In one embodiment, the scan lens 112 is provided as a fixed focal length lens and is coupled to a scan lens positioner (e.g., a lens actuator, not shown) that can move the scan lens 112 (e.g., to change the position of the beam waist along the beam axis 118). For example, the lens actuator may be provided as a voice coil that can linearly translate the scan lens 112 along the Z direction. In this case, the scan lens 112 may be formed from a material such as fused silica, optical glass, zinc selenide, zinc sulfide, germanium, gallium arsenide, magnesium fluoride, or the like. In other embodiments, scan lens 112 is provided as a variable focal length lens (e.g., a zoom lens, or a so-called "liquid lens" incorporating technology currently offered by COGNEX, VARIOPTIC, etc.) that can be actuated (e.g., via a lens actuator) to vary the position of the beam waist along beam axis 118. By varying the position of the beam waist along beam axis 118, the spot size at workpiece 102 can be varied.

[0063] In one embodiment, the scan lens 112 and the second positioner 108 are integrated into a common housing or "scan head." Thus, in embodiments in which the apparatus 100 includes a lens actuator, the lens actuator may be coupled to the scan lens 112 (e.g., so that the scan lens 112 is movable relative to the second positioner 108 within the scan head). Alternatively, the lens actuator may be coupled to the scan head (e.g., so that the scan head itself is movable, in which case the scan lens 112 and the second positioner 108 move together). In other embodiments, the scan lens 112 and the second positioner 108 are integrated into different housings (e.g., so that the housing in which the scan lens 112 is integrated is movable relative to the housing in which the second positioner 108 is integrated). The scanhead components or the entire scanhead may be a modular assembly such that scanhead components can simply be removed and replaced with other components, or one scanhead can simply be removed and replaced with another scanhead.

[0064] E. Visibility Apparatus 100 may further include one or more cameras, such as camera 113 (e.g., a CCD camera, a CMOS camera, or the like, or any combination thereof) having a field of view that encompasses the area occupied by workpiece 102 provided to apparatus 100 for processing. Camera 113 may be coupled to scan lens 112 or to the scan head described above. Camera 113 may generate image data representative of the image captured within the field of view and output this image data (e.g., as one or more image signals) to controller 114.

[0065] The image data may be analyzed, manipulated, input into an algorithm, or processed in any desired or suitable manner known in the art (e.g., at the controller 114, the remote system 126, etc., or any combination thereof) to facilitate one or more operations such as alignment of the workpiece 102 within the apparatus 100, calibration (e.g., of features formed as a result of processing the workpiece 102), visual inspection, etc., or any combination thereof.

[0066] While FIG. 1 illustrates device 100 as including only one camera 113, it will be appreciated that there may be multiple cameras 113 (e.g., differing in resolution, field of view, etc., or a combination thereof). For example, in one embodiment, device 100 may include a first camera and a second camera. The first camera may have a relatively large field of view and a relatively low resolution, and the second camera may have a relatively small field of view and a relatively high resolution. Typically, the field of view of the second camera is located within the field of view of the first camera. However, the first and second cameras may be positioned such that the field of view of the second camera is located outside the field of view of the first camera.

[0067] F. Controller Generally, apparatus 100 includes one or more controllers, such as controller 114, to control or facilitate the control or operation of apparatus 100. In one embodiment, controller 114 is communicatively coupled (e.g., via one or more wired or wireless serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof) to one or more components of apparatus 100, such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if a variable focal length lens), fixture, camera 113, VOA, beam size adjustment mechanism, etc. These one or more components of apparatus 100 are operable in response to one or more control signals output by controller 114.

[0068] For example, the controller 114 may control the operation of the first positioner 106, the second positioner 108, or the third positioner 110 to effect relative movement between the beam axis and the workpiece, and to effect relative motion between the process spot and the workpiece 102 along a path or trajectory (also referred to herein as a “process trajectory”) within the workpiece 102. It will be appreciated that any two of these positioners, or all three of these, may be controlled such that two positioners (e.g., the first positioner 106 and the second positioner 108, the first positioner 106 and the third positioner 110, or the second positioner 108 and the third positioner 110) or all three positioners simultaneously effect relative movement between the process spot and the workpiece 102 (thereby effecting a “compound relative movement” between the beam axis and the workpiece). Of course, at any one time, it is also possible to control only one positioner (e.g., first positioner 106, second positioner 108, or third positioner 110) to cause relative movement between the process spot and workpiece 102 (thereby causing "non-compound relative movement" between the beam axis and the workpiece).

[0069] Other examples of actions that can be controlled to be performed by one or more of the above-described components are described in the above-mentioned U.S. Patent Nos. 5,751,585, 5,847,960, 6,606,999, 8,680,430, and 8,847,113, or in U.S. Patent Nos. 4,912,487, 5,633,747, 5,638,267, 5,917,300, 6,314, No. 463, No. 6,430,465, No. 6,600,600, No. 6,606,998, No. 6,816,294, No. 6,947,454, No. 7,019,891, No. 7,027,199, No. 7,133,182, No. 7,133,186, No. 7,133,187, No. 7,133,188, No. 7,244,906, No. 7,245,412, No. 7,259,354, No. 7,611 ,745, 7,834,293, 8,026,158, 8,076,605, 8,288,679, 8,404,998, 8,497,450, 8,648,277, 8,896,909, 8,928,853, 9,259,802, or in U.S. Patent Application Publication Nos. 2014 / 0026351, 2014 / 0196140, 2014 / 0263201, 2014 / 0263212, 2014 / 0263223, 2014 / 0312013, or in German Federal Patent No. DE102013201968B4, or in International Patent Publication No. WO2009 / 087392, or any combination thereof, each of which is incorporated herein by reference in its entirety.In another example, the controller 114 may control the operation of any positioner (e.g., in one embodiment, the first positioner 106, the second positioner 108, or a combination thereof) comprising one or more AOD systems to vary the spot shape or spot size of a laser pulse irradiated at a process spot (e.g., by chirping an RF signal applied to one or more ultrasonic transducer elements of one or more AOD systems, by applying a spectrally shaped RF signal to one or more ultrasonic transducer elements of one or more AOD systems, or the like, or any combination thereof), as disclosed, for example, in International Patent Publication No. WO 2017 / 044646 A1, which is incorporated herein by reference in its entirety. The applied RF signal may be chirped linearly, nonlinearly, or in any desired or suitable manner. For example, the applied RF signal may be chirped at a first rate and then at a second rate to diffract a laser pulse passing through the AO cell in two different ways. In this case, the first speed may be slower or faster than the second speed.

[0070] Typically, the controller 114 includes one or more processors capable of generating the above-described control signals when executing instructions. The processor may be provided as a programmable processor (e.g., one or more general-purpose computer processors, microprocessors, digital signal processors, etc., or any combination thereof) capable of executing instructions. The instructions executable by the processor may be implemented as software, firmware, etc., or any suitable form of circuitry (including digital, analog, or mixed analog / digital circuitry) including programmable logic devices (PLDs), field programmable gate arrays (FPGAs), field programmable object arrays (FPOAs), application-specific integrated circuits (ASICs), etc., or any combination thereof. Execution of the instructions may occur on a single processor, distributed across multiple processors, in parallel across multiple processors within a device or across a network of devices, or the like, or any combination thereof.

[0071] In one embodiment, the controller 114 includes tangible media, such as computer memory, accessible by the processor (e.g., via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (e.g., magnetic tape, hard disk drives, etc.), optical disks, volatile or non-volatile semiconductor memory (e.g., RAM, ROM, NAND flash memory, NOR flash memory, SONOS memory, etc.), etc., and may be locally accessible, remotely accessible (e.g., over a network), or any combination thereof. Generally, instructions may be stored as computer software (e.g., executable code, files, instructions, etc., library files, etc.). Such computer software may be written in, for example, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, assembly language, hardware description languages ​​(e.g., VHDL, VERILOG, etc.), etc., and may be readily produced by one of ordinary skill in the art from the description provided herein. Computer software is typically stored in one or more data structures carried by the computer memory.

[0072] Although not shown, one or more drivers (e.g., RF drivers, servo drivers, line drivers, power supplies, etc.) may be communicatively coupled to inputs of one or more components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if a variable focal length lens), fixture, camera 113, VOA, beam size adjustment mechanism, etc. In one embodiment, each driver typically includes an input to which controller 114 is communicatively coupled, thereby enabling controller 114 to generate one or more control signals (e.g., trigger signals, etc.) that may be communicated to inputs of one or more drivers associated with one or more components of apparatus 100. In this manner, components such as the laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if a variable focal length lens), fixture, camera 113, VOA, and beam size adjustment mechanism are responsive to control signals generated by controller 114.

[0073] In other embodiments, although not shown, one or more additional controllers (e.g., component-specific controllers) may be communicatively coupled to inputs of drivers communicatively coupled to (and associated with) components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if a variable focal length lens), fixture, camera 113, VOA, beam size adjustment mechanism, etc. In this embodiment, each component-specific controller may be communicatively coupled to controller 114 and capable of generating one or more control signals (e.g., trigger signals, etc.) in response to one or more control signals received from controller 114. The one or more control signals may then be transmitted to inputs of the driver communicatively coupled thereto. In this embodiment, the component-specific controller may be operable in a manner similar to that described with respect to controller 114.

[0074] In other embodiments where one or more component-specific controllers are provided, a component-specific controller associated with a component (e.g., laser source 104) may be communicatively coupled to a component-specific controller associated with a component (e.g., first positioner 106, etc.). In this embodiment, one or more of the component-specific controllers may generate one or more control signals (e.g., trigger signals, etc.) in response to one or more control signals received from one or more other component-specific controllers.

[0075] G. User Interface The apparatus 100 may further include a user interface 120 communicatively coupled to the controller 114 (e.g., via one or more wired or wireless serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof). The user interface 120 may include one or more output devices, one or more input devices, or any combination thereof. Generally, an output device is any device capable of providing or communicating information through a human-perceivable stimulus (e.g., visual, auditory, tactile, etc.). Examples of output devices include a monitor, a printer, a speaker, a haptic actuator, etc. Generally, an input device is any device that allows a user of the apparatus 100 to provide instructions, commands, parameters, information, etc. to operate (or facilitate) the operation of the apparatus 100. Examples of input devices include a keyboard, a mouse, a touchpad, a touchscreen, a microphone, a camera, and the like.

[0076] H. Communication Module Optionally, device 100 includes a communications module 122 communicatively coupled to controller 114 (e.g., via one or more wired or wireless serial or parallel communications links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof). Communications module 122 is capable of transmitting data, receiving data, or both. Thus, communications module 122 may include circuitry, an antenna, connectors, etc., or combinations thereof, for transmitting and / or receiving data to other devices or networks (e.g., network 124) via wired or wireless links. In one example, communications module 122 may be a connector that, in cooperation with software or firmware within controller 114, functions as a serial port (e.g., RS232), a universal serial bus (USB) port, an IR interface, etc., or any combination thereof. In another example, communications module 122 may be a Universal Interface Driver Application Integrated Circuit (UIDA) that supports multiple different host interface protocols, such as RS-232C, IBM 46XX, keyboard wedge interface, etc., or any combination thereof. Communications module 122 may also include one or more modules, circuits, antennas, connectors, etc., as known in the art, that support other known communications modes, such as USB, Ethernet, Bluetooth, Wi-Fi, infrared (e.g., IrDa), RFID communications, etc., or any combination thereof. It will be appreciated that rather than being a separate component from controller 114, communications module 122 may be incorporated as part of controller 114 in any known or suitable manner.

[0077] Network 124 may be communicatively coupled (e.g., via one or more wired or wireless serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof) to one or more systems remote from device 100 (e.g., remote system 126 as identified in FIG. 1 ). In one embodiment, remote system 126 may be a device such as a computer (e.g., a desktop computer, a laptop computer, a tablet computer, a smartphone, etc.), a computing system (e.g., a cloud computing platform), another controller or communication module (e.g., associated with another device such as device 100), or the like, or any combination thereof. Remote system 126 may be a device owned or operated by a user of device 100, by the manufacturer of device 100, by a technician responsible for performing maintenance on device 100, or the like, or any combination thereof.

[0078] Via communications module 122 and network 124, controller 114 may communicate various data to and from remote system 126. Thus, examples of data that may be output to remote system 126 include the image data discussed above, or measurement or notification data (all of which are described in more detail below), or any combination thereof. Data output by remote system 126 (e.g., via network 124 and communications module 122) may be input to controller 114 and represent instructions, commands, parameters, information, etc. for operating device 100 or for affecting or facilitating the operation of device 100.

[0079] I. Beam Characterization Tools Optionally, apparatus 100 includes one or more beam characterization tools, such as beam characterization tool 128, capable of measuring one or more properties of the laser energy beam. Examples of properties measurable by beam characterization tool 128 include the spatial energy distribution, phase, polarization, power, etc., at a spot of the incident laser energy beam impinging on beam characterization tool 128, or any combination thereof. Accordingly, beam characterization tool 128 may be provided as at least one sensor selected from the group consisting of a slit sensor, a knife-edge sensor, a camera (e.g., CCD, CMOS, etc.), a wavefront sensor (e.g., Shack-Hartmann wavefront sensor, etc.), or other laser beam profilers known in the art, or any combination thereof. Beam characterization tool 128 may generate measurement data representative of one or more of the measured beam properties and output the measurement data (e.g., as one or more measurement signals) to controller 114. If desired, the measurement data (or data derived from the measurement data, for example, by the controller 114) can be transmitted from the controller 114 to a remote system 126 (for example, via the communications module 122 and the network 124).

[0080] 1 , beam characterization tool 128 may be configured and arranged to measure one or more properties of the laser energy beam (each also referred to herein collectively as a “beam property”) by any method known in the art. For example, beam characterization tool 128 may be configured to measure one or more properties of the laser energy beam at or near a location where workpiece 102 is processed by the laser energy beam (also referred to herein as a “process region”) (e.g., as indicated by arrow 128 a), from a location along beam path 116 (i.e., a sampling location), or a combination thereof. In one embodiment, the sampling location may be between second positioner 108 and scan lens 112 (e.g., as indicated by arrow 128 b), between first positioner 106 and second positioner 108, between laser source 104 and first positioner 106, or the like.

[0081] In other embodiments, camera 113 (e.g., a first camera, a second camera, etc., or any combination thereof) may be operated to acquire images of the spot at workpiece 102, at the fixture, at an area outside the fixture, or the like, or at any combination thereof. In some embodiments, the acquired images may then be processed by camera 113 such that the image data generated by camera 113 represents the spatial energy distribution of the spot. In this case, the image data output by camera 113 may be considered “measurement data,” and camera 113 may be considered an embodiment of beam characterization tool 128.

[0082] i. Measurements from process areas 2 and 3, the beam characterization tool 128 may be mounted to the third positioner 110 at a location outside the aforementioned support region of a fixture (not shown) that includes the third positioner 110. For example, the third positioner 110 may include one or more linear stages (e.g., as described above), and the beam characterization tool 128 may be mounted to (e.g., to the side of) the same linear stage to which the fixture is coupled. In other embodiments, the beam characterization tool 128 may be mounted to the fixture itself rather than being mounted to a linear stage. To facilitate beam property measurements, the third positioner 110 may be operated to move the beam characterization tool 128 to a position that intersects with the beam axis 118 (e.g., as shown in FIG. 2). After the beam characteristics are measured, the third positioner 110 may be operated to move the support region of the fixture (e.g., on which the workpiece 102 is supported) so that the beam axis 118 intersects with the workpiece 102 (e.g., as shown in FIG. 3).

[0083] 4, the beam characterization tool 128 may include a token 400 overlying a photodetector 402. The token 400 may include, for example, a substrate 404 and a pattern of non-transmissive targets 406 formed on the substrate 404. A frame (e.g., frame 408) may secure the token 400 over the photodetector 402. The substrate 404 is formed from a material (e.g., typically glass) that is transparent (or at least substantially transparent) to the laser energy beam propagating along the beam axis 118. In contrast, the target 406 is typically formed from a material (e.g., typically chromium or an alloy thereof) that reflects or absorbs the laser energy beam propagating along the beam axis 118.

[0084] The size, shape, or other configuration of the targets 406 may be provided as desired or advantageous. For example, with reference to FIG. 5 , the targets 406 may be arranged to form a “target grid” including solid square targets (e.g., as identified at 500), solid diamond-shaped targets (e.g., as identified at 502), hollow square targets (e.g., as identified at 504), or the like, or any combination thereof. The square targets (e.g., as identified at 500 and 504) have sides oriented along the X-axis and Y-axis (e.g., oriented at 0 degrees and 90 degrees, measured from the Z-axis). The diamond-shaped targets (e.g., as identified at 502) have sides offset from the X-axis and Y-axis (e.g., oriented at 45 degrees and 135 degrees, measured from the X-axis).

[0085] The target grid may optionally include peripheral targets (e.g., as shown at 506) surrounding the solid square target 500, the solid diamond target 502, and the hollow square target 504. While FIG. 5 shows a 12×12 target arrangement 406 (comprising targets 500, 502, and 504), it will be understood that any number of targets 406 may be provided and arranged in any desired or advantageous manner. The target grid may have a length and / or width ranging from 10 mm to 30 mm (e.g., at or about 20 mm). Each side of the peripheral target 506 may have a width w1 ranging from 1 mm to 5 mm (e.g., at or about 2.5 mm), and the targets 500, 502, and 504 may have a maximum dimension (e.g., in the X or Y direction) ranging from 100 μm to 500 μm (e.g., at or about 250 μm). The sides of the hollow square target 504 may have a width w2 in the range of 5 μm to 15 μm (eg, at or around 10 μm).

[0086] In one embodiment, the laser energy beam transmitted through the scan lens 112 may be directed at a spot on the target 406 of the token 400 with a fluence (e.g., a first fluence) high enough to melt or ablate the material forming the target 406. In such an embodiment, the photodetector 402 has an active area (i.e., the area of ​​the photodetector capable of detecting light, shown in FIG. 5 as the area enclosed by the dashed square 508) that is smaller than the area of ​​the target grid (when viewed in the top view shown in FIG. 5). The active area 508 of the photodetector 402 may have sides with lengths of 5 mm to 20 mm (e.g., 10 mm or less).

[0087] In another embodiment, the laser energy beam transmitted through scan lens 112 is irradiated at a spot on target 406 of token 400 with a fluence (e.g., the second fluence) that is insufficient to melt or ablate the material forming target 406, but is high enough to damage photodetector 402. In this case, referring to FIG. 4 , beam characterization tool 128 may include an optical filter 410 (e.g., a neutral density filter) disposed between token 400 and photodetector 402 to reduce the fluence of the transmitted laser energy beam incident on photodetector 402 (e.g., to a fluence lower than the second fluence) to prevent damage to photodetector 402.

[0088] In yet another embodiment, the laser energy beam transmitted through scan lens 112 is directed at a spot on target 406 of token 400 with a fluence (e.g., a third fluence) that is insufficient to melt or ablate the material forming target 406 and insufficient to damage photodetector 402. In this case, optical filter 410 can be omitted from beam characterization tool 128.

[0089] In one embodiment, the operation of one or more components of apparatus 100 can be selectively controlled (e.g., via controller 114, user interface 120, remote system 126, etc., or any combination thereof) to ensure that a spot illuminated on target 406 is illuminated with a first fluence or a second fluence. Similarly, the operation of one or more components of apparatus 100 can be selectively controlled (e.g., via controller 114, user interface 120, remote system 126, etc., or any combination thereof) to ensure that a spot illuminated on photodetector 402 is illuminated with a second fluence or a third fluence.

[0090] ii. Measurements from the beam path In one embodiment, referring to FIG. 6 , the apparatus 100 may include a beam splitter 600 (e.g., a beam splitter cube as shown, a partially reflecting mirror, a fiber optic beam splitter, etc., or any combination thereof) positioned at a position within the beam path 116 (i.e., the “sampling position” discussed above). The beam splitter 600 may be located between the second positioner 108 and the scan lens 112, between the first positioner 106 and the second positioner 108, between the laser source 104 and the first positioner 106, or a similar location. Generally, however, the beam splitter 600 splits the incident laser energy beam into a process beam and a sample beam. The process beam propagates along the beam path 116 (e.g., ultimately through the scan lens 112), and the sample beam propagates along a beam path 602 toward the beam characterization tool 128.

[0091] J. Laser Sensor Systems In one embodiment, apparatus 100 includes a laser sensor system configured to measure laser energy or power. Measurement data generated by the laser sensor system (e.g., in response to measuring the laser energy or power) is output to controller 114 (and optionally to remote system 126), where it can be processed to support various functions such as real-time pulse energy control (e.g., to compensate for changes in laser power), system calibration (e.g., to compensate for changes in transmission through the AOD system of first positioner 106 with respect to RF power and frequency, etc.), or any combination thereof. Examples of functions that can be implemented using measurement data from the laser sensor system are described in the aforementioned U.S. Patent No. 7,244,906, or in the aforementioned U.S. Patent Application Publication Nos. 2014 / 0196140, 2014 / 0263201, or 2014 / 0263223, or the like, or any combination thereof.

[0092] 7 , in one embodiment, apparatus 100 includes a first positioner 106 provided as an AOD system (e.g., as described above) capable of deflecting beam path 116 along different axes. For example, first positioner 106 may include a first single-axis AOD system 700 (e.g., an X-axis AOD system) and a second single-axis AOD system 702 (e.g., a Y-axis AOD system). First positioner 106 may also include other optical elements, such as a half-wave plate 704, disposed between first single-axis AOD system 700 and second single-axis AOD system 702, as needed. Apparatus 100 may also include a relay module 706 (e.g., including a first relay lens (or first group of lenses) 708, a second relay lens (or second group of lenses) 710, and an aperture 712 disposed therebetween). Apparatus 100 may also include a quarter wave plate 714 located optically "upstream" of second positioner 108 (e.g., provided as described above). Apparatus 100 may also include a plurality of mirrors 716 located in beam path 116. Generally, mirrors 716 are positioned and configured to bend or redirect beam path 116 in a desired or advantageous manner toward the various components described above.

[0093] In the above-described configuration, the laser sensor system (identified at 718 in FIG. 7 ) is configured to measure laser energy from a portion of the laser energy beam sampled at a location along the beam path 116 between the first positioner 106 and the second positioner 108. Accordingly, the apparatus 100 may further include a beam splitter 720 (e.g., a partially reflective mirror as shown, a beam splitter cube, a fiber optic beam splitter, etc., or any combination thereof) positioned and configured to direct (e.g., reflect) a majority of the light in the laser energy beam exiting the relay module 706 (e.g., along path 116) toward the second positioner 108, while permitting a small amount of light (e.g., 2% or thereabouts) to propagate along path 722 to the laser sensor system 718.

[0094] Generally, the laser sensor system 718 includes a photodetector 724 configured to measure laser energy. However, because the laser sensor system 718 is located optically “downstream” of the first positioner 106, the readings from the photodetector 724 typically vary with the position or angle of the incident energy beam. As such, movement of the incident laser energy beam on the photodetector 724 can result in reading errors, which can lead to erroneous power control, system calibration, and the like. In one embodiment, the spatial and directional sensitivity associated with the photodetector 724 can be reduced by expanding and / or diverging the laser energy beam propagating along the path 722 (e.g., using one or more diffusers, beam expanders, etc.) before the laser energy beam strikes the photodetector 724. In such cases, the spatial uniformity of the diverged / expanded beam must be greater than the range of movement of the incident laser energy beam at the photodetector 724. In another embodiment, referring to FIG. 7 , an integrating sphere 726 is used to reduce the spatial and directional sensitivity associated with the photodetector 724. When integrating sphere 726 is provided, the components described above for expanding and / or diverging the laser energy beam propagating along path 722 before it strikes photodetector 724 (e.g., one or more diffusers, beam expanders, etc.) may be omitted (or retained, if desired).

[0095] As generally known in the art, integrating sphere 726 is an optical element that includes a hollow spherical (or at least substantially spherical) cavity, the interior surface of which is coated with a diffuse reflective coating. Integrating sphere 726 includes an illumination port 728 and a detection port 730, and is positioned such that light propagating along path 722 can enter the cavity of integrating sphere 726 through illumination port 728. Light that is incident at any point on the interior surface of the cavity is scattered and ultimately exits integrating sphere 726 at detection port 730 and is incident on photodetector 724. As configured as described above, it will be appreciated that laser sensor system 718 can be considered an embodiment of photodetector 402, as described in connection with beam characterization tool 128.

[0096] When laser sensor system 718 includes integrating sphere 726 (e.g., as shown in FIG. 7 ), the spatial and directional sensitivity associated with photodetector 724 can be further reduced than if the laser energy beam propagating along path 722 were expanded and / or diffused using one or more diffusers, beam expanders, etc. As a result, the accuracy of real-time energy measurements from photodetector 724 is improved, thereby enabling improved power control, calibration, etc., using the measurement data generated by photodetector 724. Furthermore, it is significantly easier to align photodetector 724 with light collection port 730 of integrating sphere 726 than it is to align the photodetector directly with path 722. Similarly, integrating sphere 726 can be more easily aligned with path 722 than other mechanisms, such as diffusers or beam expanders.

[0097] K. Workpiece Handling System Although not shown in FIG. 1 , a workpiece handling system may be provided. Generally, the workpiece handling system may be configured to load the workpiece 102 to be processed, unload the workpiece 102 once the workpiece 102 has been processed, or both. In embodiments in which the workpiece 102 is a relatively thin, flexible object (also known as a “web,” which may include fabric, paper, foil, laminate, FPC panel, FPC, etc., or any combination thereof), the workpiece handling system may be provided as a roll-to-roll system configured to guide the workpiece 102 (e.g., removed from a spool or roll) into the apparatus 100 for processing and to remove the processed workpiece 102 from the apparatus 100 (e.g., by loading the processed workpiece 102 onto another spool or roll). 8, a workpiece handling system configured to handle a web, such as workpiece handling system 800, may be configured to guide workpiece 102 (e.g., pulled from unwind material roll 802a comprising workpiece 102) into apparatus 100 for processing (i.e., onto fixture 804 of apparatus 100). Workpiece handling system 800 may also be configured to remove processed workpiece 102 from fixture 804 and deliver it to rewind material roll 802b comprising workpiece 102.

[0098] In the illustrated embodiment, fixture 804 is coupled to a stage of third positioner 110 of apparatus 100. In this case, third positioner 110 is provided as a split-stage positioning system as described above, and the stage carrying fixture 804 is a Y-stage. Thus, fixture 804 is movable along the Y-direction, and one or more components, such as second positioner 108, scan lens 112, etc., or a combination thereof, are movable along the X-direction on fixture 804 (e.g., by a linear stage mounted on a frame, gantry, etc.). As described above, fixture 804 is adapted to apply a force (e.g., mechanical force, electrostatic force, vacuum force, magnetic force, etc.) to workpiece 102 to secure, hold, or secure workpiece 102 (e.g., during processing of workpiece 102). Thus, fixture 804 may be provided as a vacuum chuck, electrostatic chuck, magnetic chuck, etc., as known in the art.

[0099] The workpiece handling system 800 includes an unwind assembly 808a capable of guiding a workpiece 102 into the fixture 804 (e.g., through a first port 806a of the apparatus 100) and a rewind assembly 808b capable of removing the processed workpiece 102 from the fixture 804 (e.g., through a second port 806b of the apparatus 100). The unwind assembly 808a includes an unwind spindle 810a for supporting the unwind roll 802a, an unwind idler roller 812a, a first unwind air turn 814a, an unwind dancer assembly 816a, a second unwind air turn 818a, and an unwind support system 820a. Similarly, rewind assembly 808b includes a rewind spindle 810b for supporting rewind roll 802b, a rewind idler roller 812b, a first rewind air turn 814b, a rewind dancer assembly 816b, a second rewind air turn 818b, and a rewind support system 820b. Unwind dancer assembly 816a and rewind dancer assembly 816b (each collectively referred to herein as "dancer assemblies 816") may each include a dancer roller 822 mounted on a dancer frame 824. As known in the art, an "air turn" is a cylindrical member having a surface formed with grooves, holes, or multiple holes configured to create a cushion of pressurized air between the workpiece 102 and the cylinder.

[0100] Although not shown, the workpiece handling system 800 may include one or more controllers (collectively referred to herein as "controllers") that control or facilitate the control or operation of the workpiece handling system 800. handler In one embodiment, the controller handlerThe controller is communicatively coupled (e.g., via one or more wired or wireless serial or parallel communication links such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof) to one or more of the above-mentioned components of the workpiece handling system (e.g., motors and actuators coupled to unwind spindle 810 a, rewind spindle 810 b, dancer frame 824 of dancer assembly 816, etc.) such that the one or more components are operable in response to one or more control signals output by the handler controller.

[0101] Typically, the handler controller includes one or more processors configured to generate the above-mentioned control signals upon executing instructions. The processor may be provided as a programmable processor (e.g., one or more general-purpose computer processors, microprocessors, digital signal processors, etc., or any combination thereof) configured to execute instructions. The processor-executable instructions may be implemented as software, firmware, etc., or any suitable form of circuitry (including digital, analog, or mixed analog / digital circuitry) including programmable logic devices (PLDs), field programmable gate arrays (FPGAs), field programmable object arrays (FPOAs), application-specific integrated circuits (ASICs), etc., or any combination thereof. Execution of the instructions may occur on a single processor, distributed across multiple processors, in parallel across multiple processors within a device or across a network of devices, or the like, or any combination thereof.

[0102] In one embodiment, the handler controller includes tangible media such as computer memory accessible by the processor (e.g., via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (e.g., magnetic tape, hard disk drives, etc.), optical disks, volatile or non-volatile semiconductor memory (e.g., RAM, ROM, NAND flash memory, NOR flash memory, SONOS memory, etc.), etc., and may be locally accessible, remotely accessible (e.g., over a network), or any combination thereof. Generally, instructions may be stored as computer software (e.g., executable code, files, instructions, etc., library files, etc.). Such computer software may be written in, for example, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, assembly language, hardware description languages ​​(e.g., VHDL, VERILOG, etc.), etc., and may be readily produced by one of ordinary skill in the art from the description provided herein. Computer software is typically stored in one or more data structures carried by computer memory.

[0103] In the illustrated embodiment, after the workpiece 102 is unwound from the unwind material roll 802a, it is fed over the unwind idler roller 812a, over the first unwind air turn 814a, under the dancer roller 822 of the unwind dancer assembly 816a, and over the second unwind air turn 818a before being guided onto the fixture 804 through the first port 806a (e.g., so that a portion of the workpiece 102 on the fixture 804 can be processed by the apparatus 100). From the fixture 804, the workpiece 102 is directed through a second port 806b to be fed over a second rewind air turn 818b, then under the dancer roller 822 of the rewind dancer assembly 816b, over the first rewind air turn 814b, and over the rewind idler roller 812b before finally being wound onto the rewind spindle 810b (e.g., thereby forming the rewind material roll 802b). Initially, the workpiece 102 is manually fed over and under the various rollers and air turns described above (e.g., from the unwind spindle 810a onto the fixture 804 and onto the rewind spindle 810b, as described above) to be installed into the workpiece handling system 800.

[0104] Each of the unwind spindle 810a and rewind spindle 810b is coupled to and driven (i.e., rotated) by one or more motors or other actuators (not shown, located within the first support system 818a and the second support system 818b, respectively). Thus, after initial installation, the workpiece 102 can be indexed or moved onto the fixture 804 by rotating the unwind spindle 810a and the rewind spindle 810b (each collectively referred to herein as "spindles 810") in unison. For example, as shown in FIG. 8, rotating the unwind spindle 810a and the rewind spindle 810b clockwise can move the workpiece 102 to the right. Similarly, rotating the unwind spindle 810a and the rewind spindle 810b counterclockwise can move the workpiece 102 to the left.

[0105] Unwind support system 820a may also include a motor or other actuator coupled to unwind spindle 810a to move unwind spindle 810a along its longitudinal axis (i.e., along an X-axis orthogonal to the illustrated Y- and Z-axes) to adjust or maintain a desired axial position of workpiece 102 introduced into first port 806a along dancer roller 822 of unwind dancer assembly 816a. Similarly, rewind support system 820b may include a motor or other actuator coupled to rewind spindle 810b to move dancer roller 822 of rewind dancer assembly 816b along its longitudinal axis (i.e., along the X-axis) to adjust or maintain a desired axial position of workpiece 102 exiting second port 806b.

[0106] Unwind idler roller 812a is mounted on an axle that is supported by unwind support system 820a. Similarly, rewind idler roller 812b is mounted on an axle that is supported by rewind support system 818b. The position of each axle may be adjustable (e.g., manually), but typically: Workpiece They are fixed during operation of handling system 800. Unlike unwind spindle 810a and rewind spindle 810b, unwind idler roller 812a and rewind idler roller 812b are so-called "non-driven" rollers (i.e., as known in the art, the idler rollers rotate about their respective axes as workpiece 102 passes around them).

[0107] The first unwind air turn 814a and the second unwind air turn 818a are mounted to a first support system 820a. Similarly, the first rewind air turn 814b and the second rewind air turn 818b are mounted to a second support system 820b. The position of each air turn may be adjustable (e.g., manually), but typically: Workpiece The air turns are fixed during operation of the handling system 800. Unlike idler rollers, each air turn is mounted to its respective support system such that it is rotationally fixed (e.g., so that the air turn does not rotate). During operation of the workpiece handling system 800, pressurized air (e.g., provided from a compressor or other source disposed on the support system and in fluid communication with each air turn) is supplied to each air turn to form a cushion of air between the air turn and the workpiece 102 (e.g., to prevent the workpiece 102 from contacting the air turn as it passes around the air turn).

[0108] Within each of the first dancer assembly 816a and the second dancer assembly 816b, the dancer rollers 822 are coupled to respective dancer frames 824 so that the dancer rollers 822 are rotatable about their longitudinal axes (e.g., about the X-axis as shown in FIG. 9 ), as is known in the art. Also, as shown in FIG. 9 , each dancer assembly 816 includes a pair of biasing mechanisms 900, each connecting an end of the dancer roller 822 to the dancer frame 824. Generally, during operation, the workpiece 102 applies a force to the dancer rollers 822 in the +Z direction (upward as shown in FIG. 9 ). To this end, the biasing mechanisms 900 are configured to apply an opposing force to the dancer rollers 822 in the -Z direction (downward as shown in FIG. 9 ). Therefore, the biasing mechanisms 900 may be provided as pneumatic cylinders, hydraulic cylinders, spring-driven single-acting cylinders, etc., or any combination thereof. In one embodiment, the biasing mechanism 900 is configured to apply a constant (or at least substantially constant) force to the dancer rollers 822.

[0109] 9, each dancer assembly 816 also includes a distance sensor 902 (e.g., mounted to the dancer frame 824 below the dancer roller 822) configured to measure the distance to the portion of the workpiece 102 being fed below the associated dancer roller 822 and generate sensor data representative of the measured distance. The sensor data may be output from the distance sensor 902 (e.g., as one or more sensor signals) to a controller (e.g., a handler controller). In the controller, the sensor data is used to control how the unwind spindle 810a and rewind spindle 810b rotate (e.g., in terms of direction, speed, amount of rotation, etc., or any combination thereof).

[0110] The dancer frame 824 of each dancer assembly 816 is coupled to and driven (i.e., translated or shifted along the Z axis) by one or more motors or other actuators (not shown, located within first support system 818a and second support system 818b, respectively). As described in more detail below, the dancer frame 824 of each dancer assembly 816 824 Movement of fixture 804 along the Z axis is coordinated with movement of fixture 804 along the Y direction.

[0111] The operation of workpiece handling system 800 configured as illustratively described above will now be described. Before the workpiece 102 is processed by apparatus 100, it is placed in workpiece handling system 800 (e.g., as described above). Unwind spindle 810a and rewind spindle 810b may then be driven (e.g., rotated clockwise) to advance the workpiece 102 to be processed above fixture 804. The portion of the workpiece 102 located above fixture 804 is also referred to herein as the "loading portion of workpiece 102." As the workpiece 102 is advanced, sensor signals output by distance sensors 902 of one or each of dancer assemblies 816 are used (e.g., by a handler controller) to control the manner in which unwind spindle 810a and rewind spindle 810b rotate. For example, if the sensor signal indicates that the distance between the distance sensor 902 and the workpiece 102 being fed beneath the associated dancer roller 822 (e.g., of the first dancer assembly 816a) is less than a predetermined threshold distance range, the handler controller can control the operation of the motor or actuator to decrease the speed at which the spindle (e.g., the unwind spindle 810a) rotates. If the sensor signal indicates that the distance between the distance sensor 902 and the workpiece 102 being fed beneath the associated dancer roller 822 (e.g., of the first dancer assembly 816a) is greater than a predetermined threshold distance range, the handler controller can control the operation of the motor or actuator to increase the speed at which the spindle (e.g., the unwind spindle 810a) rotates. Decreasing or increasing the speed at which the spindle rotates can maintain the distance between the distance sensor 902 and the portion of the workpiece 102 being fed beneath the associated dancer roller 822 within the predetermined threshold distance range.

[0112] After the desired portion of the workpiece 102 is advanced onto the fixture, the fixture 804 is operated (e.g., in response to control signals output by the controller 114) to apply a force (e.g., mechanical, electrostatic, vacuum, magnetic, etc.) to the loaded portion of the workpiece 102 to secure, hold, or otherwise secure the loaded portion of the workpiece 102 thereto. The fixture 804 may be moved back and forth along the Y-axis (e.g., by movement of a Y-stage of the apparatus 100) while the loaded portion of the workpiece 102 is processed by the apparatus 100. Once the loaded portion of the workpiece 102 is secured in the fixture 804, the loaded portion of the workpiece 102 may likewise be moved along the Y-axis. Generally, movement of the Y-stage supporting the fixture 804 (and thus movement of the workpiece 102) may be characterized by an acceleration that is much greater than the angular acceleration of the spindle 810.

[0113] To eliminate or reduce flutter, wrinkles, or cracks in workpiece 102 caused by differences in acceleration performance between the Y-stage supporting fixture 804 and spindle 810, dancer assembly 816 is actuated to raise or lower (e.g., along the Z-axis) in coordination with movement of fixture 804 along the Y-axis. For example, as the Y-stage supporting fixture 804 moves left along the Y-axis a distance d at a velocity v, first dancer assembly 816a moves downward along the Z-axis a half distance at half the speed (i.e., a distance d / 2 at a velocity v / 2), and second dancer assembly 816b moves upward along the Z-axis a half distance at half the speed (i.e., a distance d / 2 at a velocity v / 2). Similarly, as the Y-stage supporting the fixture 804 moves a distance d to the right along the Y-axis at a velocity v, the first dancer assembly 816a moves upward along the Z-axis at half the speed and a distance d / 2 (i.e., a distance d / 2 at a velocity v / 2), and the second dancer assembly 816b moves downward along the Z-axis at half the speed and a distance d / 2 (i.e., a distance d / 2 at a velocity v / 2). Generally, the dancer assemblies 816 are driven at an acceleration that closely matches the acceleration at which the Y-stage is driven. By raising and lowering the dancer assemblies 816 as described above, the portion of the workpiece 102 between the unwind material roll 802a and the first unwind air turn 814a (as well as the portion of the workpiece 102 between the rewind material roll 802b and the first rewind air turn 814b) can remain stationary (or at least substantially stationary) even when the fixture 804 moves the load of the workpiece 102 along the Y-axis.

[0114] To facilitate coordinated movement of dancer assembly 816 and the Y stage supporting fixture 804, apparatus 100 may include an encoder (not shown) operably coupled to the Y stage and configured to generate encoder signals (also referred to herein as “encoder data”) representing data such as the position of the Y stage, the direction the Y stage is moving, the velocity the Y stage is moving, or any combination thereof, as known in the art. The encoder may be communicatively coupled to a handler controller (e.g., via a wired or wireless serial or parallel communication link) such that encoder data commands can be sent to the handler controller. Alternatively, the encoder may be communicatively coupled to controller 114 (e.g., via a wired or wireless serial or parallel communication link). Controller 114 is communicatively coupled to the handler controller. In this alternative embodiment, the handler controller may receive the encoder data from controller 114, which receives the encoder data from the encoder. Upon receiving the encoder data, the handler controller generates and outputs one or more control signals to move dancer assembly 816, as described above.

[0115] There is inevitably a delay between when the encoder outputs an encoder signal and when the dancer assembly 816 rises or falls in response to movement of the Y stage. Typically, this delay is on the order of a few milliseconds. Because the biasing mechanism 900 of each dancer assembly 816 constantly exerts a force on the dancer rollers 822, it acts to create a delay that maintains the workpiece 102 in the desired tension until the dancer assembly 816 rises or falls in response to movement of the Y stage.

[0116] Workpiece handling system 800 configured as illustratively described above is adapted to handle a single workpiece 102 (e.g., to introduce workpiece 102 into apparatus 100 and remove workpiece 102 from apparatus 100). However, in other embodiments, the workpiece handling system may be configured to handle multiple workpieces. For example, workpiece handling system 800 can be modified to handle two workpieces. To enable handling of two workpieces, each dancer assembly 816 may be replaced with a dancer assembly such as dancer assembly 1000 shown in FIG. 10. Referring to FIG. 10, dancer assembly 1000 includes two dancer rollers (i.e., first dancer roller 822a and second dancer roller 822b (collectively "dancer rollers 822")) each attached to dancer frame 824 in the same manner (e.g., by a pair of biasing mechanisms 900) as described above with respect to FIGS. 8 and 9. The dancer assembly 1000 may also include a distance sensor 902 positioned and configured to measure the distance to the portion of the workpiece being fed beneath the associated dancer roller 822 (e.g., in the same manner as described above with respect to FIG. 9).

[0117] Additionally, each of unwind assembly 808a and rewind assembly 808b can be modified to include two spindles and two idler rollers to allow for handling of two workpieces. For example, with reference to FIGS. 11 and 12, unwind assembly 808a can be modified into unwind assembly 1100a. As shown, unwind assembly 1100a includes, in addition to the components of unwind assembly 808a described above, an unwind spindle 1102a for supporting an additional unwind roller 1104a and an unwind idler roller 1106a. As also described above with respect to FIG. 8, unwind support system 820a can include one or more motors or other actuators that move unwind spindle 1102a independently of unwind spindle 810a in the manner described with respect to unwind spindle 810a. Although not shown, rewind assembly 808b may be modified to include additional rewind spindles and additional rewind idler rollers in a manner similar to that described above with respect to FIGS.

[0118] 12 and 13, workpiece handling system 800 (modified as described above with respect to FIGS. 10-12) can handle two workpieces (e.g., a first workpiece 102a and a second workpiece 102b (each collectively referred to as "workpiece 102"). In modified unwind assembly 1100 configured as described above, first workpiece 102a and second workpiece 102b are fed over different idler rollers and under different dancer rollers of the same dancer assembly, but first workpiece 102a and second workpiece 102b are each fed over a common air turn. First workpiece 102a and second workpiece 102b are similarly fed over and under various components of rewind assembly 808b modified as described above. Depending on the diameter of the material rolls of the first workpiece 102a and the second workpiece 102b, the first workpiece 102a may move at a different speed between the associated spindle and idler roller than the second workpiece 102b. Similarly, depending on the difference in tension of the first workpiece 102a and the second workpiece 102b around the first dancer roller 822a and the second dancer roller 822b in the common dancer assembly 1000, the first dancer roller 822a may be raised or lowered in a different manner than the second dancer roller 822b.

[0119] III. EMBODIMENTS RELATED TO MEASUREMENT DATA The measurement data generated (e.g., as described above) can be processed (e.g., automatically at the controller 114, at the remote system 126, or a similar location, or any combination thereof) to predict, derive, identify, or otherwise obtain one or more spatial characteristics of the laser energy beam, one or more energy characteristics of the laser energy beam, or any combination thereof.

[0120] Examples of measurable spatial properties include spatial energy distribution, spatial phase distribution, spatial polarization distribution, and spot size. ,vinegar Pot shape ,vinegar Spot orientation, spot centroid, (e.g., M as known in the art) 2 The spot shape may be measured, calculated, predicted, or otherwise determined using any known or suitable technique (e.g., known techniques for calculating roundness, roughness, etc.). For example, roundness may be determined using the following formula:

number

[0121] Examples of energy characteristics include spot fluence, pulse energy (if the laser energy beam includes one or more laser energy pulses), average power, peak power, etc., or any combination thereof. In certain embodiments, data representing one or more of the above-mentioned characteristics, such as pulse energy, average power, peak power, etc., or any combination thereof (if the laser energy beam includes one or more laser energy pulses), may be used to facilitate the determination of an energy characteristic such as spot fluence. Data representing one or more other characteristics, such as pulse duration or pulse repetition frequency (if the laser energy beam includes one or more laser energy pulses), may be used to facilitate the determination of one or more energy characteristics. If the data is not generated as measured data, such data may be input to the controller 114 (e.g., via the user interface 120, the communications module 122, etc.) or made accessible to the controller 114, the remote system 126, etc., or any combination thereof.

[0122] The measurement data may be generated periodically (over a period of time), continuously, before or after an event, or any combination thereof. Examples of events that may initiate the generation of measurement data include the initiation of processing of a workpiece 102, the completion of processing of one or more workpieces 102, operation of the apparatus 100 for a predetermined period of time, operation of the laser source 104 for a predetermined period of time, etc., or any combination thereof. Another example of an event that may initiate the generation of measurement data includes receipt of a command to measure one or more beam characteristics (e.g., input via the user interface 120, the remote system 126, etc., or any combination thereof).

[0123] Generally, measurement data may be generated by acquiring spatial characteristics of the laser energy beam (e.g., as described above). Once data representing one or more spatial or energy characteristics (collectively referred to herein as "spot data") are acquired, the data may be interpreted, manipulated, input into, or otherwise processed by an algorithm (e.g., automatically in the controller 114, the remote system 126, or any combination thereof) to support one or more operations. Example embodiments of such operations are described in more detail below in the sections entitled "Adaptive Processing," "Process Control," and "Notification."

[0124] A. Adaptive Processing The spot data representing the spatial characteristics obtained from the measurement data can be processed to determine whether it is outside an associated threshold processing tolerance. In one embodiment, determining whether a particular spatial characteristic obtained from the measurement data is outside an associated threshold processing tolerance involves comparing the value of the particular spatial characteristic (i.e., the "measured value") to a reference value for that particular spatial characteristic. As used herein, the term "tolerance" refers to an acceptable amount of variation in the reference value for the particular spatial characteristic.

[0125] In one embodiment, if a measured value is greater than or less than a reference value for a particular spatial characteristic, the particular spatial characteristic is outside the associated threshold processing tolerance. In another embodiment, if a measured value for a particular spatial characteristic is greater than (or less than) a reference value by a threshold amount, the measured value is outside the threshold processing tolerance for the particular spatial characteristic. Upon determining that a spatial characteristic is outside the threshold processing tolerance, operation of one or more components of apparatus 100 may be controlled (e.g., automatically by controller 114, remote system 126, etc., or any combination thereof) to adjust one or more characteristics of the laser energy beam, adjust the process trajectory, or the like, or any combination thereof. Example embodiments of such responses are described in more detail below.

[0126] The reference value (or threshold amount) may be arbitrary, or may correspond to a value (or range of values) of a particular spatial characteristic used when the process was developed, when the process was deemed to achieve acceptable throughput, when the process was deemed to achieve acceptable quality, etc., or any combination thereof. In one embodiment, the threshold amount may be set manually (e.g., by a manufacturer of apparatus 100, by a user or other operator of apparatus 100, by an applications engineer or technician responsible for developing a process or recipe for processing workpiece 102, or the like, or by any combination thereof) via user interface 120, remote system 126, etc., or any combination thereof. In other embodiments, the threshold amount may be derived (e.g., at controller 114, at remote system 126, or a similar location, or any combination thereof) based (at least in part) on the amount of time that laser source 104 has been operating, on the amount of time that apparatus 100 has been operating, on the amount of time that has elapsed since scan lens 112 (or other optical element of apparatus 100) was cleaned, replaced, etc., or any combination thereof.

[0127] i. Correction of spatial characteristics Upon determining that the measured spatial characteristic is outside the threshold processing tolerance for the particular spatial characteristic, one or more control signals may be generated and output (e.g., from controller 114, remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if implemented as a variable focal length lens), VOA, beam size adjustment mechanism, beam shape adjustment mechanism, etc., to adjust operation of one or more of these components to bring the spatial characteristic back into the tolerance range. As used herein, bringing an out-of-tolerance spatial characteristic back into the tolerance range is referred to as "correcting" the out-of-tolerance spatial characteristic.

[0128] For example, if the spot size is determined to be larger than the reference spot size (or larger than the reference spot size by a threshold amount), one or more control signals can be generated and output (e.g., from controller 114, remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if provided as a variable focal length lens), beam size adjustment mechanism, etc., to adjust the operation of one or more of these components to reduce the spot size to equal the reference spot size (or to reduce the spot size to be larger than the reference spot size by an amount less than the threshold amount), thereby bringing the measured spot size back within the tolerance range.

[0129] In another example, the circularity of the spot shape is smaller than the reference circularity (or RoundnessIf the measured circularity is determined to be less than the reference circularity by a threshold amount, one or more control signals can be generated and output (e.g., from controller 114, remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of first positioner 106, second positioner 108, third positioner 110, lens actuator, scan lens 112 (if provided as a variable focal length lens), beam size adjustment mechanism, beam shape adjustment mechanism, etc., to adjust operation of one or more of these components to increase the circularity of the spot shape to equal the reference circularity (or increase the circularity to be less than the reference circularity by an amount less than the threshold amount) and thereby bring the measured circularity back within the tolerance range.

[0130] ii. Compensation for spatial characteristics Upon determining that the value of a spatial characteristic is outside the threshold processing tolerance range for a particular spatial characteristic, another determination may be made (e.g., in the controller 114, the remote system 126, etc., or any combination thereof) as to whether the value of the corresponding energy characteristic is outside the threshold processing tolerance range for the energy characteristic. Upon determining that the value of the energy characteristic is outside the threshold processing tolerance range for the energy characteristic, one or more control signals may be generated and output (e.g., from the controller 114, the remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if implemented as a variable focal length lens), the VOA, the beam size adjustment mechanism, the beam shape adjustment mechanism, etc., to adjust the operation of one or more of these components to bring the value of the energy characteristic back within the tolerance range. As used herein, bringing an out-of-tolerance energy characteristic back within the tolerance range is referred to as “compensating” for the out-of-tolerance spatial characteristic. In this case, the spatial characteristics are not necessarily "corrected" as described above, but the operation of one or more of the components described above may be controlled as necessary to reduce the extent to which the spatial characteristics lie outside their respective threshold processing tolerances.

[0131] For example, if the spot size is determined to be larger than the reference spot size (or larger than the reference spot size by a threshold amount) and, as a result, the fluence at the spot is determined to be lower than the reference fluence, one or more control signals may be generated and output to at least one selected from the group consisting of the laser source 104, the first positioner 106, the second positioner 108, the VOA, etc. (e.g., from the controller 114, the remote system 126, etc., or any combination thereof) to increase the power or amount of energy of the laser energy beam irradiated at the workpiece 102. In one embodiment, the operation of the laser source 104 may be controlled to increase the power or amount of energy of the laser energy beam output from the laser source 104, thereby bringing the fluence back within an acceptable range. The operation of the laser source 104 may be controlled by adjusting the current supplied to the laser source 104 (e.g., to a pump laser diode of the laser source 104), by adjusting the RF signal driving the laser source 104, or the like, or any combination thereof. In other embodiments, the operation of one or more of the first positioner 106, or the second positioner 108 (e.g., if either of the positioners includes an AOD system), the VOA, etc., or any combination thereof, can be controlled to reduce the degree to which these components attenuate the laser energy beam passing therethrough, thereby bringing the fluence back into an acceptable range. If desired, one or more control signals can be generated and output (e.g., from the controller 114, the remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (if provided as a variable focal length lens), the beam size adjustment mechanism, etc., to reduce the degree to which the spot size is larger than the nominal spot size.

[0132] iii.Trajectory adjustment Upon determining that the value of a spatial characteristic (e.g., spot size, spot shape, etc.) is outside the threshold processing tolerance for the particular spatial characteristic, a determination may be made (e.g., in controller 114, remote system 126, etc., or any combination thereof) as to whether a spot having the value of that spatial characteristic, when scanned along a predetermined trajectory, will form a feature having a size and / or shape that deviates from the desired size and / or shape. Upon determining that a feature having a size and / or shape that deviates from the desired size and / or shape will be formed, one or more control signals may be generated and output (e.g., from controller 114, remote system 126, etc., or any combination thereof) to at least one selected from the group consisting of first positioner 106, second positioner 108, and third positioner 110 to control operation of one or more of these components to adjust the predetermined trajectory so that the ultimately formed feature has the desired size and / or shape.

[0133] For example, (assuming the desired trajectory defines a circular via of a desired diameter), scanning the spot along the predetermined trajectory may result in the formation of a circular via having a diameter smaller than the desired diameter if the spot size is smaller than the reference spot size (or is smaller than the reference spot size by a threshold amount). Upon determining that the spot size will result in the formation of a circular via having a diameter smaller than the desired diameter, one or more control signals may be generated and output to at least one selected from the group consisting of first positioner 106, second positioner 108, and third positioner 110 (e.g., from controller 114, remote system 126, etc., or any combination thereof) to control the operation of one or more of these components to adjust the predetermined trajectory so that the ultimately formed circular via has the desired diameter.

[0134] In another example (still assuming the desired trajectory defines a circular via of the desired diameter), scanning the spot along the predetermined trajectory will result in the formation of an elliptical via if the spot shape has a circularity that is less than the reference spot circularity (or is less than the reference spot circularity by a threshold amount). If it is determined that the spot shape will result in the formation of an elliptical via rather than a circular shaped via, one or more control signals can be generated and output to at least one selected from the group consisting of first positioner 106, second positioner 108, and third positioner 110 (e.g., from controller 114, remote system 126, etc., or any combination thereof) to control the operation of one or more of these components to adjust the predetermined trajectory so that the ultimately formed via has the desired circularity.

[0135] B. Process Control The stored data may include measurement data, spot data, or other data (e.g., data representing the pulse duration or pulse repetition frequency if the laser energy beam includes one or more pulses of laser energy), data generated or acquired during visual inspection, and / or any combination thereof. In one embodiment, such data may be stored (e.g., in a database) in association with supporting information representing the identity of the tool 100 (e.g., serial number, model number, etc.), the identity of the workpiece 102 being (or having been) processed by the tool 100 (e.g., batch or lot number, serial number, model number, etc.), the date and / or time the data was generated or acquired, and / or any combination thereof. Collectively, this stored data and information is referred to as "process control data." The database may be local (e.g., in computer memory of the controller 114 or accessible to the controller 114), located remotely from the tool 100 (e.g., in computer memory of the remote system 126 or accessible to the remote system 126), or the like, or any combination thereof. The process control data may also include data obtained from or generated by one or more downstream test or inspection systems (e.g., automated optical inspection (AOI) systems, automated x-ray inspection (AXI) systems, in-circuit test (ICT) systems, wafer probe systems, etc.) that test or inspect the workpiece 102 following processing by the tool 100.

[0136] Once the process control data is stored, it may then be interpreted, manipulated, input into an algorithm, or otherwise processed (e.g., at the controller 114, the remote system 126, etc., or any combination thereof) to support one or more operations. For example, the process control data may be processed to implement known statistical process control (SPC) methods (e.g., to understand limits associated with a process performed by the apparatus 100 or to understand limits related to specifications for the workpiece 102 or features formed on the workpiece 102), to identify and / or eliminate causes of process variation, to monitor the production process, to detect changes in process variation, to predict whether corrective maintenance or preventive maintenance is required, to predict when (e.g., the time and / or date) preventive maintenance should be performed, or for similar purposes, or any combination thereof. As used herein, "maintenance" may include one or more actions, such as testing, measuring, part replacement, cleaning, etc. It will be appreciated that such SPC methods may be facilitated by processing the process control data to generate one or more process control charts. Additionally, the process control data may be accessed (e.g., via the user interface 120, or via a remote system 126, or a combination thereof) for any other suitable or desired purpose.

[0137] The SPC method may be performed periodically (over a period of time) or continuously, or may be performed before or after an event, or any combination thereof. Examples of events that may initiate execution of an SPC method include the initiation of processing of a workpiece 102, the completion of processing of one or more workpieces 102, operation of the apparatus 100 for a predetermined period of time, operation of the laser source 104 for a predetermined period of time, etc., or any combination thereof. Another example of an event that may initiate execution of an SPC method includes receipt of a command (e.g., input via the user interface 120, the remote system 126, etc., or any combination thereof) to measure one or more beam characteristics.

[0138] In one embodiment, a first SPC method can be implemented (e.g., by the controller 114, the remote system 126, etc., or any combination thereof) to determine whether process control data indicates a degradation in the quality of one or more features formed by processing the workpiece 102, using techniques known in the art. Optionally, if the first SPC method indicates a degradation in the quality of one or more features formed by processing the workpiece 102, a second SPC method can be implemented (e.g., by the controller 114, the remote system 126, etc., or any combination thereof) to determine whether spatial or energy characteristics indicate anomalous data or a deviation from a previous trend, using techniques known in the art. In one embodiment, the first SPC method can generate data indicating that corrective or preventive maintenance is required if the quality of one or more features formed by processing the workpiece 102 has degraded. Alternatively, in other embodiments, the data indicating the need for corrective or preventive maintenance may be generated only if the second SPC method determines that the spatial or energy characteristics indicate anomalous data or a deviation from a previous trend.

[0139] In one embodiment, the spot data and other process control data may be interpreted, manipulated, input to, or otherwise processed by any desired or suitable known method into an algorithm (e.g., a machine learning algorithm) (e.g., at the controller 114, the remote system 126, etc., or any combination thereof) to determine values ​​of one or more spatial or energy characteristics that result in unacceptable feature quality for a given process, or to identify trends in related spatial or energy characteristics to determine when preventative maintenance should be performed to avoid unacceptable feature quality, or for similar purposes, or any combination thereof.

[0140] A first SPC method may be implemented (e.g., at the controller 114, the remote system 126, etc., or any combination thereof) to determine whether process control data indicates a degradation in the quality of one or more features formed by processing the workpiece 102, using techniques known in the art. Optionally, if the first SPC method indicates a degradation in the quality of one or more features formed by processing the workpiece 102, a second SPC method may be implemented (e.g., at the controller 114, the remote system 126, etc., or any combination thereof) to determine whether spatial or energy characteristics indicate anomalous data or a deviation from a previous trend, using techniques known in the art. In one embodiment, the first SPC method may generate data indicating that corrective or preventive maintenance is required if the quality of one or more features formed by processing the workpiece 102 has degraded. Alternatively, in another embodiment, the data indicating the need for corrective or preventive maintenance may be generated only if the second SPC method determines that the spatial or energy characteristics indicate anomalous data or a deviation from a previous trend.

[0141] C. Notification Upon determining that a spatial or energy characteristic of the laser energy beam is outside a threshold processing tolerance, notification data may be generated (e.g., automatically by the controller 114, the remote system 126, etc., or any combination thereof). The notification data may indicate that the characteristic is out of tolerance, or may indicate that a measurement of the characteristic is out of tolerance, or may indicate the date and / or time that the characteristic was determined to be out of tolerance, or may identify the device 100 (e.g., by serial number, model number, etc.) having the out-of-tolerance characteristic, or the like, or any combination thereof. In one embodiment, the notification data may indicate that corrective or preventive maintenance should be performed on the device 100 (e.g., based on the results of performing one or more SPC methods, as described above). In embodiments in which the notification data indicates that maintenance should be performed, automatic control of the device 100 may be performed (e.g., by methods described above in the section entitled "Adaptive Processing"), or automatic control of the device 100 may be omitted.

[0142] Once the notification data is generated, it may be provided or communicated in a user-friendly form (e.g., visually, audibly, etc.) via an output device associated with user interface 120, remote system 126, etc., or any combination thereof, in a manner known in the art. In embodiments in which the notification data is provided or communicated via remote system 126, the notification data may be communicated to the user via text, email, push notification, in-app message, etc., or any combination thereof.

[0143] In other embodiments, the controller 114 and / or remote system 126, upon acquiring the spatial or energy characteristics of the laser energy beam, generates notification data regardless of whether such characteristics are out of tolerance, in which case the notification data does not necessarily indicate that the characteristics are out of tolerance.

[0144] D. Other Embodiments, Considerations, Impact, etc. Spot quality and size may vary between different laser processing tools 100 and may also vary over time (e.g., from the time the tool 100 is installed, through process development, to the time a large number of workpieces 102 are processed). These variations mean that a set of process parameters developed on a first tool 100 at time T1 may have one or more first spatial or energy characteristics C1, but a customer may want to use the same process parameters on a second tool 100, or a third tool 100, etc. (all of which include the same components as the first tool 100), and also on the first tool 100 at time T2, etc. At time T2, the first, second, third, and fourth tools 100 will have one or more second spatial or energy characteristics C2, one or more third spatial or energy characteristics C3, one or more fourth spatial or energy characteristics C4, and one or more fifth spatial or energy characteristics C5, respectively. This will result in a decrease in process yield unless the process is engineered to be robust to these variations in spatial or energy characteristics. The above-described embodiments compensate for possible variations in spatial or energy characteristics to maintain desired throughput and process yield.

[0145] Spot quality and size may also change over time and temperature due to optical contamination and other external factors. These changes mean that one set of process parameters that provides a given process quality for a given material with a given tool 100 at time T1 and one or more spatial or energy characteristics C1 may result in different or inadequate quality for the same material with the same tool 100 at a later time T2 and one or more spatial or energy characteristics C2 (different from C1). The above-described embodiments can accommodate these changes by providing an approach that facilitates corrective and preventative maintenance.

[0146] V. Scanning Method Embodiments As used herein, the term "scanning technique" can refer to the manner in which a process spot is scanned relative to the workpiece 102 (e.g., within a first scanning range, a second scanning range, a third scanning range, etc., or any combination thereof), or the manner in which the first scanning range is scanned within a second scanning range, or the manner in which either the first scanning range or the second scanning range is scanned within a third scanning range, etc., or any combination thereof. In general, a scanning technique can be characterized by one or more parameters such as the process trajectory in which the process spot is scanned, the direction (i.e., the direction in which the process spot, first scanning range, second scanning range, etc., or any combination thereof is scanned), the scan speed (i.e., the speed at which the process spot, first scanning range, second scanning range, etc., or any combination thereof is scanned), etc., or any combination thereof.

[0147] A. Resonant Scanning Embodiments As described above, the position of the process spot of a laser energy beam deflected by a resonant scanning mirror system varies sinusoidally as a function of time. Therefore, when the laser source 104 outputs a laser energy beam consisting of a train of laser pulses having a constant (or substantially constant) pulse repetition frequency, the resonant scanning mirror system deflects the train of laser pulses such that the laser pulses irradiate multiple process spots on the workpiece 102 that are not uniformly distributed along an axis (e.g., when performing processes such as cutting, drilling, welding, scribing, marking, and photoresist exposure). See, for example, FIG. 14. FIG. 14 illustrates the non-uniform distribution of process spots 1400 that can result when a resonant scanning mirror system is used to deflect a laser pulse beam along an arbitrary axis. This can make it difficult to distribute the laser energy uniformly or in a desired manner across the workpiece 102.

[0148] In one embodiment, sinusoidal scanning can be compensated for by controlling the operation of the laser source 104 to vary the pulse repetition frequency of the laser pulses in the output laser energy beam (e.g., so that the change in pulse repetition frequency is in phase with the sinusoidal oscillation of the resonant scanning mirror system).

[0149] In another embodiment, sinusoidal scanning can be compensated for by providing a first positioner 106 that includes an AOD system (e.g., any of the AOD systems described above) and providing a second positioner 108 as a resonant scanning mirror system. In this embodiment, the resonant scanning mirror system of the second positioner 108 is positioned and configured to move the beam axis 118 along a first axis, and the first positioner 106 includes a first AOD system that is positioned and configured to move the beam axis 118 along the first axis. The first AOD system may then be driven (e.g., upon application of one or more RF signals to one or more ultrasonic transducer elements, each acoustically coupled to an AO cell) in a manner that compensates for changes in acceleration of an oscillating mirror in the resonant scanning mirror system during operation of the second positioner 108 (e.g., such that laser pulses irradiate multiple process spots on the workpiece 102 that are at least substantially uniformly distributed along the axis). See, e.g., FIG. 15 . 15 illustrates the uniform (or at least substantially uniform) placement of the process spot 1400 that can be achieved when the laser pulse beam is deflected along any axis using the first AOD system of the first positioner 106 and the resonant scanning mirror system of the second positioner 108. It will be appreciated that the first AOD system may be driven in any suitable or desired manner and need not necessarily be driven to compensate for changes in the acceleration of the oscillating mirror in the resonant scanning mirror system. Optionally, the first positioner 106 can include a second AOD system positioned and configured to move the beam axis 118 along a second axis different from the first axis. In this case, the first axis can be one of the X-axes, and the second axis can be the Y-axis.

[0150] B. Ease of feature formation In general, the first positioner 106 can be operated to scan the process spot along the X direction (e.g., in the +X direction or the −X direction) and / or along the Y direction (e.g., in the +Y direction or the −Y direction) while the second positioner 108 scans the first scanning range along the X direction (e.g., in the +X direction or the −X direction), or while the second positioner 108 scans the first scanning range along the Y direction (e.g., in the +Y direction or the −Y direction), or while the third positioner 110 scans the first and / or second scanning range along the X direction (e.g., in the +X direction or the −X direction), or while the third positioner 110 scans the first and / or second scanning range along the Y direction (e.g., in the +Y direction or the −Y direction), or any combination thereof. However, it should be understood that the first positioner 106 can be operated to scan the process spot along the X direction (e.g., in the +X direction or the −X direction) and / or along the Y direction (e.g., in the +Y direction or the −Y direction) when the second positioner 108 is not scanning the first scanning range, or when the third positioner 110 is not scanning the first scanning range or the second scanning range, or any combination thereof. It should also be understood that the direction in which the process spot is scanned by the first positioner 106 at any time can be the same as or different from the direction in which the first scanning range is scanned within the second scanning range by the second positioner 108, or the direction in which the first scanning range is scanned within the third scanning range by the third positioner 110, or any combination thereof.

[0151] In some embodiments, the workpiece 102 is provided as a PCB panel, a PCB, an FPC panel, an FPC, an IC, an ICP, a semiconductor device, etc. As such, the workpiece 102 may include one or more component structures, such as a conductor structure (e.g., a film, foil, etc. that may be formed from copper, a copper alloy, a wiring or conductive line structure including one or more metals such as copper, titanium, titanium nitride, tantalum, etc., or any combination thereof), a dielectric structure (e.g., a build-up film, a fiberglass reinforced epoxy laminate, an interlayer dielectric material, a low-k dielectric material, a solder resist, etc.), or any combination thereof. In some embodiments, the workpiece 102 may include a dielectric structure (e.g., a film comprised of a polymer such as glass fiber reinforced epoxy laminate, polyimide, polyester, PEN, PET, solder resist, etc.) attached on a first side thereof to a first conductor (e.g., a copper or copper alloy foil that may have an exposed surface that is darkened (e.g., by a chemical reaction, a laser darkening process, etc.) or not) and, optionally, attached on a second side opposite the first side thereof to a second conductor (e.g., a pad, trace, foil, etc. comprised of copper or a copper alloy). By removing material through material ablation (e.g., during a cutting process, a drilling process, an engraving process, a routing process, etc., or any combination thereof), one or more features (e.g., one or more openings, slots, trenches, blind vias, through vias, slotted vias, etc.) may be formed in or on one or more components of the workpiece 102. As used herein, the term "feature region" refers to the region of the workpiece 102 that is processed to form the features.

[0152] In general, unless expressly stated, the term "ablation" can refer to "direct ablation," "indirect ablation," or any combination thereof. Direct ablation of material within the workpiece 102 occurs when ablation is primarily caused by the material's breakdown due to absorption (e.g., linear absorption, nonlinear absorption, or any combination thereof) of energy within the irradiated laser energy beam. Indirect ablation (also known as "lift-off") of material within the workpiece 102 occurs when ablation is primarily caused by melting and vaporization due to heat transferred within and from adjacent material that absorbs the energy within the irradiated laser energy beam.

[0153] In one embodiment, the features may be formed to extend completely or partially through one or more components of the workpiece 102 (e.g., one or more conductive structures, one or more dielectric structures, etc., or any combination thereof). In one embodiment, the conductive or dielectric structures may have a thickness in the range of 5 μm to 500 μm. However, it will be understood that the conductive or dielectric structures may have a thickness less than 5 μm or greater than 500 μm. Thus, the thickness of the conductor or dielectric structure may be greater than or equal to 1 μm, 3 μm, 5 μm, 10 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 50 μm, 70 μm, 80 μm, 100 μm, 110 μm, 120 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 550 μm, 600 μm, etc., or may be between any of these values. Similarly, the thickness may be less than 550 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 120 μm, 110 μm, 100 μm, 80 μm, 70 μm, 50 μm, 40 μm, 35 μm, 25 μm, 20 μm, 18 μm, 15 μm, 10 μm, 5 μm, 3 μm, 1 μm, 0.5 μm, 0.1 μm, etc., or between any of these values.

[0154] Generally, feature formation can be performed by scanning a process spot along a process trajectory defining one or more scan patterns (e.g., by controlling the first positioner 106 to scan the process spot through one or more corresponding scan patterns within a first scanning range). A feature can be formed by scanning the process spot along a scan pattern (also referred to as a "feature formation" scan pattern) only once or multiple times, depending on one or more factors, such as the desired depth of the feature to be formed, the material to be removed during feature formation, one or more parameters of the laser pulse beam applied during feature formation, or any combination thereof. When the process spot is scanned multiple times along a scan pattern, the process spot can be repeatedly scanned along the same scan pattern (i.e., the same scan pattern can be used repeatedly). In other embodiments, at least two different scan patterns can be used during feature formation. When the same scan pattern is repeatedly used, a subsequently used scan pattern can have the same direction (e.g., measured relative to the feature axis) as the previously used scan pattern, or can have a different direction from the previously used scan pattern.

[0155] i. High Repetition Rate Laser Source Considerations As described above, the first positioner 106 has a first positioning bandwidth ranging from 8 kHz to 250 MHz. If the first positioner 106 is provided as one or more AOD systems, the first positioner 106 may have a positioning bandwidth greater than, equal to, or less than 50 kHz, 75 kHz, 80 kHz, 100 kHz, 250 kHz, 500 kHz, 750 kHz, 1 MHz, 5 MHz, 10 MHz, 20 MHz, 40 MHz, 50 MHz, 75 MHz, 100 MHz, 125 MHz, 150 MHz, 175 MHz, 200 MHz, 225 MHz, 250 MHz, etc., or any value between these values. The relatively large positioning speed of an AOD system (e.g., compared to a galvanometer mirror system) allows for effective utilization of a laser source 104 capable of outputting laser pulses at a high pulse repetition rate (e.g., greater than or equal to 150 kHz, 175 kHz, 225 kHz, 250 kHz, 275 kHz, 500 kHz, 800 kHz, 900 kHz, 1 MHz, 1.5 MHz, 1.8 MHz, 1.9 MHz, 2 MHz, 2.5 MHz, 3 MHz, 4 MHz, 5 MHz, 10 MHz, 20 MHz, 50 MHz, 60 MHz, 100 MHz, 150 MHz, 200 MHz, 250 MHz, 300 MHz, 350 MHz, 500 MHz, 550 MHz, 600 MHz, 900 MHz, 2 GHz, 10 GHz, etc., or a value between any of these values). Such high repetition rate laser sources are generally unsuitable for processing workpiece 102 using only a galvanometer mirror system to move beam axis 118 due to the relatively slow positioning speeds associated with known galvanometer mirror systems. Thus, the highest available positioning speed of apparatus 100 is determined by the smaller of the first positioning bandwidth or the pulse repetition rate of laser source 104.

[0156] When operated with a high repetition rate laser source, the pulse energy of an individual laser pulse is generally lower than the pulse energy of an individual laser pulse output by a laser source having the same (or nearly the same) average power but a lower pulse repetition rate. Peak ablation efficiency ("ablation efficiency" is defined as the unit amount of material removed per unit time per power, i.e., mm 3 It has been determined that generating laser pulses having relatively low pulse energy but a relatively high pulse repetition rate can be advantageous for many laser processing applications because the optimal fluence for a given material (which may be defined as fluence per second / s / W) is often significantly lower than the fluence used to optimize throughput and quality for the same laser processing application using a laser source with a relatively low pulse repetition rate. Applicant has determined that irradiating laser pulses with a relatively high pulse repetition rate and a relatively low pulse energy enables processing at near-optimal fluences with typical beam waist dimensions for many materials, thereby increasing the efficiency with which the workpiece 102 can be processed. For example, Applicant has directly observed that using a laser source with a high pulse repetition rate (e.g., producing laser pulses with relatively low pulse energy having pulse durations in the range of 10 ns to 80 ns) can drill blind vias in workpieces such as PCBs, FPCs, etc. at a higher throughput than can be achieved at the same (or nearly the same) average power using a laser source with a relatively low pulse repetition rate (e.g., producing laser pulses with relatively high pulse energy having the same pulse durations in the range of 10 ns to 80 ns). Additionally, applicants have observed increased blind-via drilling throughput at a pulse repetition rate of 300 kHz compared to a pulse repetition rate of 200 kHz, even though the average power at 200 kHz was more than 50% higher than the average power at 300 kHz.

[0157] ii. Example Scan Pattern Embodiments Examples of scan patterns for forming vias and other features, such as holes, openings, recesses, trenches, etc., include scan patterns 1600, 1700, 1800, and 1900, as shown in Figures 16, 17, 18, and 19, respectively, or any combination thereof. In general, the scan pattern may resemble or describe a raster pattern (e.g., as shown in Figure 16), a star polygon or star-shaped polygon (e.g., as shown in Figure 17), a spiral or a set of arcs or circles (e.g., concentrically arranged or as shown in Figure 18), a circle, a set of circles, or one or more shapes (e.g., an ellipse, triangle, square, rectangle, or other regular or irregular shapes), etc., or any combination thereof. In one embodiment, one or more scan patterns (e.g., one or more of scan patterns 1600, 1700, 1800, and 1900, or any combination thereof) can be used to remove material (e.g., by direct ablation, indirect ablation, or any combination thereof) from one or more conductive structures, one or more dielectric structures, etc., or any combination thereof, during the formation of features such as circular openings, vias, etc.

[0158] 16-19, dashed line 1602 represents a desired boundary at work surface 102a for a feature (e.g., a circular opening or via in this example) to be formed in a conductive or dielectric structure of workpiece 102. For purposes of illustration of this example, when the feature is formed in workpiece 102, the feature can be characterized as including a "top" formed in work surface 102 and extending along an axis into workpiece 102 (e.g., terminating within workpiece 102 or extending completely through workpiece 102). This portion of the feature that terminates within workpiece 102 or resides on the other side of workpiece 102 is sometimes referred to herein as the "bottom" of the feature.

[0159] figure 16From the figure 19 While the boundary 1602 of the feature being formed (also referred to herein as the "feature boundary") is illustrated as being circular, it will be understood that the boundary may have any suitable or desirable shape (e.g., oval, square, rectangular, triangular, hexagonal, irregular, etc., or any combination thereof). In the embodiments described herein, the shape of the boundary 1602 at the top and bottom of the feature is the same or similar (e.g., circular). In other embodiments (e.g., embodiments in which material removal occurs by direct ablation and multiple scan patterns are scanned during material processing), the boundary 1602 at the top of the feature may be different in shape from the boundary 1602 at the bottom of the feature. For example, the top of the feature may have a circular boundary 1602, while the top of the feature may have a boundary 1602 that is oval, rectangular, etc.

[0160] The centers of the locations for the process spots (each collectively referred to as a "spot location" or inclusively referred to as "spot locations") in the scan patterns are indicated by diamonds 1604. Although scan patterns 1600, 1700, 1800, and 1900 are illustrated as having a particular arrangement of spot locations 1604 shown, it will be understood that any scan pattern may include more or fewer spot locations in any suitable or desired arrangement. The arrangement of spot locations 1604 within a scan pattern or along a common scan line (i.e., which may be characterized by the number of spot locations, the location of the spot locations, the pitch of adjacent spot locations, etc., or any combination thereof) can vary depending on factors such as the thermal conductivity, thermal diffusivity, specific heat capacity, absorptivity, etc., of the material at or near the spot location, the viscosity of the material at or near the spot location during feature formation, the absorptivity (with respect to the impinging laser energy beam) of the material at or near the spot location, the presence or absence of conductive or dielectric structures near the spot location, the geometric configuration of conductive or dielectric structures near the spot location, the spot size, the type and shape of the spatial intensity profile, the pulse duration, the fluence, the pulse repetition rate, the scan speed, the size and shape of the feature being formed, etc., or any combination thereof. In general, the arrangement of commonly-located spot locations along one scan line of a particular scan pattern may be the same as or different from the arrangement of commonly-located spot locations along other scan lines of that particular scan pattern.

[0161] Of the spot locations 1604, spot location 1604a represents the first spot location in a scan pattern to be illuminated with a laser pulse, and spot location 1604b represents the last spot location in the scan pattern to be illuminated with a laser pulse. Thus, the solid lines connecting the spot locations 1604 indicate the sequence in which the spot locations 1604 are machined (e.g., by one or more illuminated laser pulses). However, it should be understood that the spot locations 1604 within a scan pattern may be machined in any other desired sequence (which may alter the configuration of the solid lines) or may be machined randomly. At any point during machining, the spot locations 1604 within a scan pattern may be machined in any other desired sequence (which may alter the configuration of the solid lines) or randomly. 1604 can be characterized as the previously machined spot position (i.e., the spot position where the laser pulse was applied), the currently machined spot position (i.e., the spot position where the laser pulse is applied), and the to-be machined spot position (i.e., the spot position where the laser pulse will be applied).

[0162] In one embodiment, the location of the spot locations 1604 and the sequence in which the spot locations 1604 are processed are selected, as needed, to reduce or avoid undesirable heat buildup within the workpiece 102 during feature formation (e.g., which may result in undesirable cracking, melting, evaporation, ablation, crystallization, annealing, carbonization, oxidation, etc.). In another embodiment (as described in more detail below), the location of the spot locations 1604 and the sequence in which the spot locations 1604 are processed are selected, as needed, to affect (e.g., reduce) the taper of the ultimately formed feature. In another embodiment, the location of the spot locations 1604 and the sequence in which the spot locations 1604 are processed are selected, as needed, to promote heating of the workpiece 102 to promote efficient formation of one or more features on or within the workpiece 102.

[0163] Depending on one or more factors such as the pulse repetition rate, the first positioning bandwidth, the scanned scan pattern, etc., at least two temporally consecutive laser pulses (e.g., two laser pulses, three laser pulses, five laser pulses, eight laser pulses, ten laser pulses, twenty laser pulses, etc.) may be applied to the same spot location 1604 or to different spot locations 1604. In this case, the pulse repetition rate may generally be characterized as being greater than the first positioning bandwidth. However, in other embodiments, the pulse repetition rate may be equal to or less than the first positioning bandwidth.

[0164] The period of time during which temporally consecutive laser pulses are applied to the same spot location 1604 (or are applied in the local vicinity of a common spot location 1604) is referred to herein as the "dwell time" associated with spot location 1604. For purposes of explanation, if a laser pulse is applied within 1 μm of spot location 1604, then the laser pulse can be considered to be applied in the local vicinity of spot location 2504. In one embodiment, a laser pulse can be considered to be localized near spot location 1604 if the laser pulse is irradiated within 10.0 μm, 8.0 μm, 7.0 μm, 6.0 μm, 5.0 μm, 4.0 μm, 3.5 μm, 3.0 μm, 2.5 μm, 2.0 μm, 1.5 μm, 1.0 μm, 0.9 μm, 0.8 μm, 0.75 μm, 0.7 μm, 0.65 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.25 μm, 0.2 μm, 0.15 μm, 0.1 μm, 0.08 μm, 0.05 μm, 0.01 μm of spot location 1604, or within less than 0.01 μm of spot location 1604.

[0165] In the illustrated embodiment, the scan pattern can be characterized as including one or more rows of sequentially processed spot locations 1604. The spot locations 1604 in each such row can generally be characterized as being arranged along a common scan line. Sequentially processed spot locations arranged on a common scan line are generally closer to each other than sequentially processed spot locations arranged on different scan lines. The scan lines may be straight (e.g., as shown in FIG. 16 or FIG. 17), curved (e.g., as shown in FIG. 18 or FIG. 19), or the like, or any combination thereof. For example, the scan pattern 1600 shown in FIG. 16 includes multiple straight, parallel scan lines, while the scan pattern 1700 shown in FIG. 17 includes multiple straight scan lines that are angled relative to each other. The scan lines in the scan pattern 1700 extend along axes that extend radially (or nearly radially) from the center of the feature boundary 1602 (or from a central region surrounding the center of the feature boundary 1602) toward the feature boundary 1602. The scan pattern 1800 shown in FIG. 18 includes a plurality of concentrically arranged arc-shaped scan lines (with the outermost radial scan lines extending along the desired feature boundary 1602). In FIG. 18, the spot locations 1604 are illustrated as being evenly distributed circumferentially around the center of the circular feature boundary 1602. In other embodiments, the spot locations 1604 may be distributed in a Fibonacci sequence-like configuration centered on the circular feature boundary 1602. Irradiating the workpiece with Fibonacci sequence-like spot locations 1604 may help improve the uniformity of the applied laser energy distributed in the scan pattern. However, it will be understood that other suitable or desired arrangements of the spot locations 1604 are contemplated.For example, different ones of the concentric ring spot positions 1604 shown in Figure 18 may be circumferentially offset from one another to enhance or tailor the distribution of laser energy imparted to the workpiece as the scan pattern is scanned. The scan pattern 1900 shown in Figure 19 includes a single arc-shaped scan line (e.g., extending along the desired feature boundary 1602).

[0166] At least one laser pulse is applied to each spot location 1604. In one embodiment, multiple laser pulses are applied to more than one spot location 1604 (or to localized vicinity of a common spot location 1604). Generally, the same number of laser pulses may be applied to at least two spot locations 1604 in the scan pattern, or different numbers of laser pulses may be applied to at least two spot locations 1604 in the scan pattern.

[0167] In general, the pitch between adjacent spot positions 1604 is considered to be greater than the distance encompassed within a local neighborhood of the spot position 1604. In one embodiment, the pitch between adjacent spot positions within a scan pattern may range from 0.1 μm to 50 μm. Similarly, the pitch between adjacent spot positions 1604 located along a common scan line may range from 0.1 μm to 50 μm. Thus, the pitch between adjacent spot positions 1604 (generally within a scan pattern or located along a common scan line) may be greater than or equal to 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 3.5 μm, 4.5 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 55 μm, 60 μm, 80 μm, etc. The pitch between spot locations may be less than, or between any of these values, or may be less than, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 10 μm, 5 μm, 4.5 μm, 3.5 μm, 3 μm, 2 μm, 1.5 μm, 1 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.08 μm, 0.05 μm, 0.01 μm, etc., or may be less than, or between any of these values. For purposes of this description, the pitch between spot locations is measured as the distance between the centers of two adjacent spot locations. Two spot locations are considered adjacent to one another if there are no intervening spot locations between them.

[0168] The pitch between pairs of adjacent spot locations 1604 (generally within a scan pattern or along a common scan line) can be constant, variable, or any combination thereof. In one embodiment, the pitch between adjacent spot locations along a common scan line can increase or decrease in a direction extending from a spot location illuminated by one laser pulse to another spot location illuminated by a subsequent laser pulse. Thus, the pitch between pairs of adjacent spot locations 1604 along a common scan line can be constant, increase, decrease, or any combination thereof as the scan line is moved. In general, the spot size of the illuminated laser pulse and the pitch between pairs of adjacent spot locations 2504 can be selected or set so that the spot areas illuminated by the illuminated laser pulses at the pairs of adjacent spot locations 1604 overlap or do not overlap.

[0169] In one embodiment, the arrangement of scan lines within the scan pattern (i.e., which can be characterized by the number of scan lines, the orientation of the scan lines relative to other scan lines, the orientation of the scan lines relative to the boundary 1602, the length of the scan lines, the pitch between adjacent scan lines, etc.) is as shown in FIG. 16 From the figure 19The arrangement is not limited to that shown in FIG. 1 and may vary depending on one or more factors, such as those discussed above with respect to the arrangement of spot locations 1604. Thus, a scan pattern may have an odd number of scan lines or an even number of scan lines. In one embodiment, the number of scan lines in a scan pattern may range from 1 to 64. For example, the number of scan lines in a scan pattern may be greater than or equal to 2, 4, 8, 16, 32, 50, 60, etc., or may be less than 64, 32, 16, 8, 4, or 2. It should also be understood that a scan pattern may have more than 64 scan lines. Within a scan pattern, at least some of the scan lines may be arranged symmetrically (or at least substantially symmetrically) or asymmetrically. Examples of symmetric arrangements include rotationally symmetric arrangements (i.e., n-fold rotational symmetry, where n is an integer greater than 1, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 50, etc.) and reflectionally symmetric arrangements.

[0170] VI. EMBODIMENTS RELATING TO MODULATION OF BEAM PROPERTIES As discussed above, the laser energy beam (whether continuous or pulsed) applied to the workpiece 102 during processing of the workpiece 102 may be configured with a variety of wavelengths, average powers, spatial intensity profile types, M 2The laser energy beam may be characterized by one or more characteristics such as a laser beam repetition rate, a spatial intensity profile shape, a spot size, an optical intensity, a fluence, etc. If the laser energy beam includes one or more laser pulses, the beam may also be characterized by one or more characteristics such as a pulse repetition rate, a pulse duration, a pulse energy, a peak power, etc. All of these characteristics of a laser energy beam (whether continuous or pulsed) are collectively and comprehensively referred to herein as the "characteristics" or simply the "beam characteristics" of the laser energy beam. These and other beam characteristics may be modified in other suitable or desired manners known in the art or disclosed herein (in this section or elsewhere). It should be noted that configuring the applied laser energy beam (e.g., in the sense of identifying and selecting a particular combination of beam characteristics) in a manner that provides optimal or acceptable workpiece processing requires a comprehensive understanding of the fundamental laser-material interactions with respect to the materials comprising the workpiece 102 and the laser processing that is being performed. Using this knowledge and an appropriate laser source, laser processing techniques can be developed that optimize process throughput and / or quality.

[0171] For example, the spot size may be adjusted by controlling the operation of a lens actuator, the scan lens 112 (if implemented as a variable focal length lens), a beam size adjustment mechanism, or the like, or any combination thereof.

[0172] In another example, M 2 The factor and spatial intensity profile shape can be adjusted by operating one or more AOD systems (e.g., first positioner 106 or otherwise) in the manner described above. 2The techniques described above for operating an AOD system to vary factors can be modified to adjust the type of spatial intensity profile of the laser pulse beam in the manner described above. For example, the spectrum of an RF signal applied to one or more transducers of an AOD system (e.g., first positioner 106 or otherwise) can be shaped to have a non-Gaussian spectral profile (e.g., a rectangular or "top hat" spatial profile). When such an RF signal is applied to one or more transducers of an AOD system (e.g., first positioner 106 or otherwise), the laser pulses exiting the AOD system can be altered in a manner to produce laser pulses with a non-Gaussian spatial intensity profile (e.g., a rectangular or "top hat" spatial intensity profile). In one embodiment, the spectrally shaped RF signal is not chirped. In other embodiments, the spectrally shaped RF signal may be chirped. Thus, depending on how the AOD system is driven (i.e., in response to the applied one or more RF signals), the laser pulses exiting the AOD system may have a non-Gaussian spectral profile (e.g., a rectangular or "top hat" spatial intensity profile). 2 The beam may differ from the incident laser pulse in one or more characteristics, such as the beam factor, the type of spatial intensity profile, the shape of the spatial intensity profile, and the spot size.

[0173] In another example, the pulse duration, pulse repetition rate, or any combination thereof, can be adjusted by varying the operation of laser source 104. In this example, laser source 104 may be any suitable pulsed laser source capable of generating and outputting laser pulses at a variable pulse repetition rate and / or having a variable pulse duration (e.g., the PYROFLEX and QUASAR lasers mentioned above are known to have such capabilities). If laser source 104 includes a QCW or CW laser source, laser source 104 may further include a pulse gating unit (e.g., an acousto-optic (AO) modulator (AOM), beam chopper, etc.) that temporally modulates the beam of laser radiation output from the QCW or CW laser source. In embodiments in which first positioner 106 includes an AOD system, the AOD system may be operated in any suitable or known manner to function as a pulse gating unit.

[0174] In other examples, the pulse energy can be adjusted by varying the operation of the laser source 104, or by controlling the operation of a VOA, or the like, or a combination thereof. In embodiments in which the first positioner 106 includes an AOD system, the AOD system may be operated in any suitable or known manner to vary the degree to which the laser energy beam passing through the AO cell is attenuated.

[0175] The beam characteristics of the laser pulses applied to the common spot location (or applied near the common spot location) may be the same or different. For example, one or more characteristics, such as spot size, pulse energy, pulse duration, pulse repetition rate, etc., of a first laser pulse applied to or near a particular spot location (or a first set of laser pulses sequentially applied to or near the particular spot location) may be the same or different from the corresponding characteristics of a second laser pulse applied to or near the particular spot location (or a second set of laser pulses sequentially applied to or near the particular spot location). Similarly, the beam characteristics of laser pulses sequentially applied to different spot locations in a common scan pattern may be the same or different. One or more (or all) beam characteristics of the laser energy beam applied to the workpiece 102 during processing of the workpiece 102 may be constant (or at least substantially constant), modulated (e.g., so as to be substantially non-constant), or any combination thereof. Examples of embodiments for modulating one or more beam characteristics during processing of a feature are described below.

[0176] i. Feature formation in multilayer workpieces A workpiece having a multi-layer structure can be processed to form one or more features that penetrate multiple layers of the workpiece. In one embodiment, the multi-layer workpiece 102 can be processed to form features, such as openings, slots, vias or other holes, grooves, trenches, scribe lines, kerfs, recessed areas, etc., that at least partially penetrate two different layers of the multi-layer workpiece 102. The different layers of the multi-layer workpiece 102 may be formed from different materials, may have different optical absorption characteristics (e.g., with respect to the impinging laser energy beam), or any combination thereof. Thus, for example, a feature may be formed in the multi-layer workpiece 102 by ablating a first layer of the workpiece 102 with an impinging laser energy beam characterized by a first set of beam characteristics to expose a second layer of the workpiece 102. The first set of beam characteristics may then be (e.g., wavelength, average power, type of spatial intensity profile, M 2 A second layer of the workpiece 102 may be ablated using an irradiating laser energy beam characterized by a second set of beam characteristics that differ (in terms of beam size, spatial intensity profile shape, spot size, light intensity, fluence, pulse repetition rate, pulse duration, peak power, etc., or any combination thereof). The characteristics in the second set of beam characteristics may be identical to corresponding characteristics in the first set of beam characteristics so long as at least one characteristic is greater than, less than, or different from the corresponding characteristic in the first set of beam characteristics.

[0177] For example, the multilayer workpiece 102 may be a PCB panel, PCB, FPC panel, FPC, etc. that includes a dielectric structure (e.g., a film comprised of a polymer, such as fiberglass reinforced epoxy laminate, polyimide, polyester, PEN, PET, solder resist, etc.) bonded on a first side thereof to a first conductor (e.g., a copper or copper alloy foil that may have an exposed surface that is darkened (e.g., by a chemical reaction, a laser darkening process, etc.) or not) and, optionally, bonded on a second side opposite the first side thereof to a second conductor (e.g., a pad, trace, foil, etc. comprised of copper or a copper alloy). The multilayer workpiece 102 may be processed to form vias that extend completely through the first conductor and at least partially through the dielectric structure. The vias may terminate in the second conductor (in which case they are blind vias) or may extend completely through the second conductor (in which case they are through vias).

[0178] In the above example, a laser energy beam characterized by a first set of beam properties may be irradiated onto a first conductor in a first processing step to directly or indirectly ablate the first conductor to form an opening exposing the dielectric structure (and may be scanned, e.g., by the scanning techniques exemplarily described above, as needed). Thereafter, in a second processing step, a laser energy beam characterized by a second set of beam properties may be irradiated onto the dielectric structure through the opening (and may be scanned, e.g., by the scanning techniques exemplarily described above, as needed) to directly ablate the dielectric structure to form a hole extending into the dielectric structure.

[0179] In one embodiment, the first and second sets of beam characteristics may be identical in wavelength (e.g., the irradiating laser energy beam may have a wavelength in the UV, visible, or IR portion of the electromagnetic spectrum) but may differ in fluence, light intensity, or the like, or any combination thereof. For example, the fluence may be higher during the first processing step than during the second processing step. Between the first and second processing steps, the fluence may be adjusted by reducing the pulse energy of the irradiating laser pulse beam, by increasing the spot size of the irradiating laser pulse beam, or the like, or any combination thereof. For example, the spot size of the laser pulse beam irradiated during the second processing step (i.e., the "second spot size") may be increased relative to the spot size of the laser pulse beam irradiated during the first processing step (i.e., the "first spot size") to reduce the fluence at the process spot (e.g., below a threshold fluence capable of directly ablating the materials of the first and second conductors) without reducing the average power. As a result, the number of pulses required to form a hole in a dielectric structure can be kept relatively low, avoiding damage to adjacent conductive structures. In certain embodiments, the first spot size can be in the range of 2 μm (or thereabouts) to 35 μm (or thereabouts), and the second spot size, which is larger than the first spot size, can be in the range of 40 μm (or thereabouts) to 150 μm (or thereabouts). For example, the first spot size can be equal to (or approximately equal to) 2 μm, 3 μm, 5 μm, 7 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, etc., or a value between these values, and the second spot size can be equal to (or approximately equal to) 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 125 μm, 140 μm, 155 μm, etc.

[0180] In other embodiments, the first and second sets of beam characteristics may be identical in wavelength (e.g., the irradiating laser energy beam may have a wavelength in the UV, visible, or IR portion of the electromagnetic spectrum), but may differ in pulse duration, pulse repetition rate, or the like, or any combination thereof. For example, the pulse duration may be longer during the first processing step than during the second processing step. In this case, the pulse repetition rate may be lower during the first processing step than during the second processing step. If the pulse duration during the first processing step (i.e., the "first pulse duration") is longer than the pulse duration during the second processing step (i.e., the "second pulse duration"), the first pulse duration may be longer than 30 ns (e.g., in the range of 30 ns (or thereabouts) to 200 ns (or thereabouts)), and the second pulse duration may be shorter than 40 ns (e.g., in the range of 800 ps (or thereabouts) to 40 ns (or thereabouts)). Provided that the corresponding pulse repetition rate during the first processing step (i.e., the "first pulse repetition rate") is lower than the corresponding pulse repetition rate during the second processing step (i.e., the "second pulse repetition rate"), the first pulse repetition rate may be 500 kHz or less (e.g., in the range of 150 kHz (or thereabouts) to 500 kHz (or thereabouts)), and the second pulse repetition rate may be greater than 300 kHz (e.g., in the range of 500 kHz (or thereabouts) to 2 MHz (or thereabouts)). It will be appreciated that the maximum available pulse energy will depend on the particular combination of pulse duration and pulse repetition rate, but may be as much as several hundred μJ in some combinations.

[0181] In other embodiments, the first and second sets of beam characteristics may be identical in wavelength (e.g., the irradiating laser energy beam may have a wavelength in the UV, visible, or IR region of the electromagnetic spectrum), pulse duration, pulse repetition rate, etc., or any combination thereof, but may differ in pulse energy. For example, the pulse energy may be higher during the first processing step than during the second processing step. The pulse energy during the first processing step (i.e., the "first pulse energy") may be sufficiently high to promote efficient and uniform removal of the first conductive material, and the pulse energy during the second processing step may be higher. Energy (i.e., the "second pulse energy") may be lower than the first pulse energy but still high enough to ablate the dielectric structure. In one embodiment where the feature being formed is a blind via, the second pulse energy may be low enough to avoid undesirably damaging the second conductor.

[0182] ii. Other Considerations for Feature Formation Regardless of whether the workpiece 102 is multi-layered or not, it may be preferable to modulate the pulse energy (e.g., by any of the methods described above) so that the pulse energy of the laser pulse irradiated onto the workpiece 102 at the start of scanning a scan pattern (e.g., any of the scan patterns described above) is higher than the pulse energy of the laser pulse irradiated onto the workpiece 102 at the end of scanning that scan pattern.

[0183] In other embodiments, the spot size of the irradiated laser pulse can be modulated (e.g., by any of the methods described above) depending on the location of the spot location within the scan pattern. For example, for the spot patterns described above, the spot size of the irradiated laser pulse can be modulated so that it is smaller at spot locations adjacent the feature boundary 1604 than the spot size of laser pulses irradiated at spot locations not adjacent the feature boundary 1604. A smaller spot size adjacent the feature boundary 1604 can be useful for forming features with sidewalls that have a relatively small taper, while a larger spot size away from the feature boundary 1604 can be useful for quickly removing material from the workpiece 102.

[0184] In other embodiments, regardless of whether the workpiece 102 is multilayered or not, it may be preferable to modulate the pulse energy (e.g., by any of the methods described above) so that the pulse energy of the laser pulse irradiated to the workpiece 102 at the start of scanning a scan pattern (e.g., any of the scan patterns described above) is higher than the pulse energy of the laser pulse irradiated to the workpiece 102 at the end of scanning that scan pattern.

[0185] In other embodiments, whether or not the workpiece 102 has multiple layers, it may be preferable to adjust the degree to which each laser pulse diffracted by the AOD system of the first positioner 106 is chirped (e.g., pulse by pulse) as a function of the location of the impinged spot position, the depth into the workpiece 102 at which the laser pulse is impinged, the temperature of the material in the workpiece 102 being processed, the temperature of material proximate to the material in the workpiece 102 being processed, or the like, or any combination thereof. In one embodiment, the chirp may be adjusted so that the second conductor described above is polished after the first and second processing steps have been performed.

[0186] IV. Conclusion The foregoing describes embodiments and examples of the present invention and is not to be construed as limiting thereof. While several specific embodiments and examples have been described with reference to the drawings, those skilled in the art will readily recognize that many modifications to the disclosed embodiments and examples and other embodiments are possible without materially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the claims. For example, those skilled in the art will understand that the subject matter of any sentence, paragraph, example, or embodiment can be combined with part or all of the subject matter of any other sentence, paragraph, example, or embodiment, except where such combinations are mutually exclusive. Therefore, the scope of the present invention should be determined by the following claims and any equivalents of such claims to be included therein.

Claims

1. A laser processing device, a laser source capable of generating a beam of laser energy propagated along a beam path; at least one component capable of performing at least one operation on a laser energy beam selected from the group consisting of: (a) deflecting the laser energy beam; (b) adjusting a beam waist position of the laser energy beam along the beam path; (c) adjusting a power of the laser energy beam; and (d) adjusting a beam size of the laser energy beam; a sensor capable of measuring one or more characteristics of the beam of laser energy and generating measurement data representative of one or more of the measured beam characteristics; at least one processor, processing the measurement data to obtain one or more measurements associated with the one or more measured properties of the laser energy beam; outputting one or more control signals to the at least one component if the one or more measurements are outside a threshold processing tolerance; at least one processor capable of Equipped with the one or more control signals are configured to cause the at least one component to perform at least one operation on the laser energy beam such that the one or more measured characteristics of the laser energy beam are within the threshold processing tolerance; the sensor is capable of measuring one or more spatial properties of the laser energy beam; Laser processing equipment.

2. the one or more measured characteristics include one or more spatial characteristics of the laser energy beam and one or more energy characteristics of the laser energy beam; The at least one processor processing the measurement data to obtain one or more measurements associated with the one or more measured spatial characteristics and the one or more measured energy characteristics of the laser energy beam; outputting one or more control signals to the at least one component when the one or more measurements associated with the one or more measured spatial characteristics are outside a first threshold processing tolerance and the one or more measured energy characteristics are outside a second threshold processing tolerance. It is possible to the one or more control signals are configured to cause the at least one component to perform at least one operation on the laser energy beam such that the one or more measured energy characteristics of the laser energy beam are within the second threshold processing tolerance. The laser processing device according to claim 1 .

3. the at least one component includes at least one positioner capable of effecting relative movement between the beam path and a workpiece; the one or more measured properties include one or more spatial properties of the laser energy beam; The at least one processor processing the measurement data to obtain one or more measurements associated with the one or more measured spatial properties of the laser energy beam; outputting one or more control signals to the at least one component when the one or more measurements associated with the one or more measured spatial characteristics are outside a threshold processing tolerance; It is possible to the one or more control signals are configured to cause the at least one positioner to modify a predetermined trajectory along which a process spot illuminated by the laser energy beam is scanned while causing relative movement between the beam path and the workpiece by the at least one positioner. The laser processing device according to claim 1 .

4. The laser processing apparatus of claim 1 , wherein the at least one component includes the laser source.

5. 3. The laser processing apparatus of claim 1, wherein the at least one component comprises at least one selected from the group consisting of an acousto-optic deflector (AOD) system, a microelectromechanical system (MEMS) mirror system, a fast steering mirror (FSM) element, a galvanometer mirror system, and a workpiece stage.

6. The laser processing apparatus according to claim 1 or 2, wherein the at least one component includes a variable optical attenuator.

7. 3. The laser processing apparatus according to claim 1, wherein the at least one component includes at least one selected from the group consisting of a zoom lens, a motorized variable beam expander, a deformable mirror, a variable radius mirror, a variable focus moire lens, a motorized Z-axis lens, a motorized iris diaphragm, and a motorized aperture wheel.

8. The laser processing apparatus of claim 3 , wherein the at least one component includes the at least one positioner.

9. 10. The laser processing apparatus of claim 8, wherein the at least one positioner comprises at least one selected from the group consisting of an acousto-optic deflector (AOD) system, a microelectromechanical system (MEMS) mirror system, a fast steering mirror (FSM) element, a galvanometer mirror system, and a workpiece stage.

10. 4. The laser processing apparatus according to claim 2 or 3, wherein the one or more spatial characteristics of the laser energy beam include at least one selected from the group consisting of a spatial energy distribution, a spatial phase distribution, a spatial polarization distribution, a spot size, a spot shape, a spot orientation, a spot center of gravity, and a spot quality.

11. The laser processing apparatus of claim 10 , wherein the one or more spatial characteristics of the beam of laser energy include a spot size.

12. The laser processing apparatus of claim 10 , wherein the one or more spatial characteristics of the beam of laser energy include a spot shape.

13. The laser processing apparatus of claim 2 , wherein the one or more measured energy characteristics include at least one selected from the group consisting of spot fluence, pulse energy, average power, and peak power.

14. The laser processing apparatus according to claim 1 , wherein the sensor is provided as a camera.

15. The laser processing apparatus according to claim 1 , wherein the sensor is provided as a slit sensor.

16. The laser processing apparatus according to claim 1 , wherein the sensor is provided as a knife-edge sensor.

17. The laser processing apparatus according to claim 1 , wherein the sensor is provided as a wavefront sensor.

18. The laser processing apparatus of claim 1 , wherein the sensor is positioned and configured to measure the one or more properties of the beam of laser energy at an end of the beam path.

19. The laser processing apparatus of claim 1 , wherein the sensor is positioned and configured to measure the one or more properties of the beam of laser energy at a position along the beam path.

20. 20. The laser processing apparatus of claim 19, further comprising a beam splitter disposed in the beam path and configured to transmit a portion of laser energy propagating along the beam path to the sensor.

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