Laser processing apparatus facilitating directed inspection of laser-processed workpieces and methods of operating the same

Abstract

To provide a laser-processing apparatus for forming features in a workpiece.SOLUTION: A laser-processing apparatus for forming features in a workpiece includes at least one sensor capable of generating process control data representing a) at least one characteristic of the apparatus either before, during or after the processing of the workpiece to form a set of features, b) at least one characteristic of the workpiece either before, during or after the processing of the workpiece to form a set of features, and / or c) at least one characteristic of an ambient environment in which the apparatus is located either before, during or after the processing of the workpiece to form a set of features. Thereby, the process control data is processed to estimate whether or not any of the features formed in the workpiece are defective, and a location of any feature estimated to be defective is identified.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] I. Technical Field The embodiments disclosed herein generally relate to a laser processing apparatus and a method for laser processing of a workpiece. Description of Related Art

[0002] II. Description of Related Art Laser processing can be performed on a number of different workpieces using a variety of lasers that perform a variety of processes. For example, laser microfabrication processes have been developed for forming features such as through-holes or blind holes in workpieces such as printed circuit boards (PCBs) or integrated circuit (IC) packages. The goal of a laser microfabrication process is to form features of consistent quality across the entire workpiece. Means for defining the quality of a feature include the position, size, and shape of the feature. Other means include sidewall angle, bottom surface texture, the amount and texture of debris remaining on the feature after processing, and the like.

[0003] One problem in laser microfabrication is that due to non-uniformities in the workpiece, differences in the quality of the features may occur when performing a microfabrication process at two different locations on the workpiece with the same laser parameters. Examples of workpiece differences that can affect the results include differences in thickness, differences in workpiece flatness, and differences in surface pretreatment that increase or decrease the reflectivity of the workpiece to laser power. These variations are not constant across the entire workpiece and can vary depending on the location of each feature. Furthermore, these variations can occur repeatedly from workpiece to workpiece in a given number of workpieces due to normal variations within manufacturing tolerances.

[0004] Other phenomena that affect the ability of a laser micromachining system to form feature portions having a certain quality are aging and / or damage to the laser source used to generate the laser energy beam and the optical components used to direct the laser energy at the workpiece. When the laser source ages, its ability to output laser energy having certain characteristics (e.g., average power) can deteriorate. Further, when the optical components age, the optical components are subject to contamination, most notably from debris from the micromachining process itself and damage from the high-power laser energy passing through the optical components. These or other forms of degradation can cause changes in the size, shape, intensity, or other characteristics of the laser spot projected onto the workpiece, which in turn can cause changes in the size, shape, depth, or other dimensions of the feature portions formed by the micromachining.

[0005] Some laser micromachining systems use real-time control to vary the characteristics of the laser energy beam while machining the feature portions in an attempt to mitigate the effects of changes in the laser source or optical components due to aging or damage. In some systems, a photodetector is used to monitor the laser power while the workpiece is being machined. The output from the photodetector is used to adjust the laser power incident on the workpiece in real time so as to ensure a part of the source of variability of the laser power at the workpiece. This can be achieved by operating an optical component such as a variable attenuator to adjust the amount of laser energy ultimately irradiated onto the workpiece to a level suitable for forming each feature portion.

[0006] Information regarding the characteristics of a laser energy beam used to form respective feature portions on a workpiece is recorded, and an identifier for specifying the position of the feature portion in the workpiece is associated with the information (thereby generating, for example, "process data"). After the machining of the workpiece is completed, the generated process data can be analyzed to predict a time when a problem may occur for the laser microfabrication system to form feature portions of suitable quality. For example, if the recorded information indicates that more laser power than the laser power available to the system would have been required, it is conceivable that in the feature portions formed with less laser power, the material has not been sufficiently removed.

[0007] It is also known to inspect the machined workpiece to evaluate the quality of the formed feature portions. The result of the inspection can be compared with the process data (if created), and the performance of the characteristics of the laser energy beam used to form the feature portions on the workpiece can be evaluated. Post-processing inspection, such as that performed on a workpiece such as a PCB, is performed manually (for example, by a user inspecting the workpiece using a microscope) or automatically (for example, by automated optical inspection "AOI"). When the inspection is performed manually, since hundreds or thousands of feature portions can be formed on one workpiece, the feature portions to be inspected (i.e., via holes) will constitute only a single sample out of the total number of feature portions to be formed. When the inspection is performed by AOI, immediately after the feature portions are formed (if the feature portions are through vias), or immediately after a post-processing step is performed to clean the feature portions (if the feature portions are non-through vias and a desmear, etching, and shadowing process is performed to remove debris in the holes), all the feature portions of one or more workpieces in the lot can be inspected.

[0008] Conventional post-processing inspection methods can be problematic for a number of reasons. In the case of manual inspection, the operator or quality inspector using the microscope may become fatigued, which could lead to overlooking defects when concentration decreases. When inspecting all features (e.g., using the AOI method), unnecessary extra time is spent inspecting areas of the workpiece where defective features are less likely to be formed. When inspecting features randomly, areas of the workpiece where defective features are more likely to be formed may not be inspected, resulting in overlooking quality problems that could cause the workpiece to be discarded. Overview

[0009] One embodiment of the present invention can be broadly characterized as a laser processing apparatus for forming a feature on a workpiece. The apparatus includes a laser source capable of generating a laser energy beam, a scanning lens arranged to focus the laser energy beam so that the focused laser energy beam can propagate to the workpiece, at least one beam positioner arranged between the laser source and the scanning lens and capable of scanning the focused laser energy beam with respect to the workpiece within a scanning range projected onto the workpiece by the scanning lens, the workpiece, at least one stage capable of causing relative movement between the workpiece and at least one selected from the group consisting of the scanning lens and the camera, a camera having a field of view and capable of acquiring an image of an object within the field of view, and at least one sensor capable of generating process control data representing at least one selected from the group consisting of a) at least one characteristic of the apparatus either before, during, or after the workpiece is processed to form a set of features, b) at least one characteristic of the workpiece either before, during, or after the workpiece is processed to form a set of features, and c) at least one characteristic of the surrounding environment in which the apparatus is located either before, during, or after the workpiece is processed to form a set of features. The apparatus may further include a controller communicably coupled to one or more databases in which the process control data is stored in association with auxiliary information representing the positions of the respective features formed on the at least one stage, the camera, and the workpiece. The controller is capable of executing or facilitating the execution of a feature candidate selection process, whereby the process control data is processed to predict whether any of the features formed on the workpiece have defects, and the positions of the features predicted to have defects are identified.

Brief Description of the Drawings

[0010]

Figure 1

[0011]

Figure 2

[0012] Examples of embodiments will be described below with reference to the accompanying drawings. Unless explicitly stated, in the drawings, the sizes, positions, and distances between components, features, elements, etc. are not necessarily to scale and are exaggerated for ease of understanding. The same numbers throughout the drawings mean the same elements. For this reason, the same or similar numbers may be described with reference to other drawings even if they are not mentioned or explained in the corresponding drawings. Also, elements without reference numerals may be described with reference to other drawings.

[0013] The terms used in the specification are for the purpose of describing particular exemplary embodiments only and are 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 form is intended to include the plural form unless the content clearly indicates otherwise. Further, the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude 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 not only the sub-ranges between the upper and lower limits thereof, but also the upper and lower limits. Unless otherwise indicated, terms such as "first" and "second" are used only to distinguish elements from each other. For example, a certain node can be referred to as a "first node," and similarly, another node can be referred to as a "second node," or vice versa.

[0014] Unless otherwise indicated, terms such as "about" and "around" mean that the quantity, size, formulation, parameter, and other quantities and characteristics need not be exact and need not be exact, and may be approximate, and / or larger or smaller as appropriate, reflecting tolerances, conversion factors, rounding, measurement errors, etc., and other factors known to those skilled in the art. In this specification, spatially relative terms such as "downward", "below", "lower", "upward", and "upper" may be used to facilitate explanation when describing the relationship of one element or feature to another element or feature as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations in addition to the orientation shown in the figures. For example, an element described as being "downward" or "below" another element or feature will face "upward" of the other element or feature when the object in the figure is inverted. Thus, the exemplary term "downward" can include both upward and downward orientations. When the object faces other orientations (e.g., rotated 90 degrees or in other orientations), the spatially relative descriptors used in this specification can be interpreted accordingly.

[0015] The section headings used in this specification are for organization purposes only and should not be construed as limiting the subject matter described, unless otherwise specifically referred to. 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 the present disclosure should not be construed as limited to the examples of embodiments described herein. Rather, these examples and embodiments are provided so that the present disclosure is complete and inclusive and conveys the scope of the present disclosure to those skilled in the art.

[0016] I. Summary The embodiments described herein generally relate to methods and apparatus for laser processing (or more simply, "processing") a workpiece. Generally, laser radiation is applied to the workpiece to heat, melt, evaporate, ablate, damage, decolorize, polish, roughen, carbonize, foam, or modify one or more properties or characteristics of one or more materials that form the workpiece (e.g., chemical composition, atomic structure, ionic structure, molecular structure, electronic structure, microstructure, nanostructure, density, viscosity, refractive index, magnetic permeability, relative permittivity, texture, color, hardness, transmittance to electromagnetic radiation, etc., or any arbitrary combination thereof), such that the processing is carried out either globally or partially. The material to be processed may be present outside the workpiece before or during processing, or may be entirely located within the workpiece before or during processing (i.e., not present outside the workpiece).

[0017] As specific examples of processes that can be performed by the disclosed laser processing apparatus, there are via drilling or formation of other holes, cutting, punching, welding, scribing, engraving, marking (e.g., surface marking, subsurface marking, etc.), laser-induced forward transfer, cleaning, bleaching, repair of high-brightness pixels (e.g., color filter darkening, modification of OLED materials, etc.), film removal, surface texturing (e.g., roughening, smoothing, etc.), or the like, or any combination thereof. Thus, as a result of the processing, one or more features that can be formed on or within the workpiece may include openings, slots, vias or other holes, grooves, trenches, scribelines, kerfs, recesses, conductive traces, ohmic contacts, resistance patterns, marks that can be read by humans or by machines (e.g., comprising one or more regions within or on such a workpiece having one or more characteristics distinguishable visually or in texture), or the like, or any combination thereof. Features such as openings, slots, vias, holes, etc. may have any suitable or desirable shape (e.g., circular, elliptical, square, rectangular, triangular, tubular, or the like, or any combination thereof) in top view. Further, features such as openings, slots, vias, holes, etc. may extend completely through the workpiece (e.g., to form so-called "through vias", "through holes", etc.), or may extend only partially within the workpiece (e.g., to form so-called "non-through vias", "non-through holes", etc.).

[0018] Workpieces that can be processed can be characterized generically as being formed from one or more metals, polymers, ceramics, composites, or any arbitrary combination thereof (e.g., regardless of whether it is an alloy, a compound, a mixture, a solution, a composite, etc.). Thus, 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 (e.g., regardless of whether it is an alloy, a composite, etc.), conductive metal oxides (e.g., ITO, etc.), transparent conductive polymers, ceramics, waxes, resins, interlayer dielectric materials (e.g., silicon oxide, silicon nitride, silicon oxynitride, etc., low-k dielectric materials such as methylsilsesquioxane (MSQ), hydrogen silsesquioxane (HSQ), tetraethylorthosilicate fluoride (FTEOS), etc., or any arbitrary combination thereof), organic dielectric materials (e.g., SILK, benzocyclobutene, Nautilus (all manufactured by Dow), polytetrafluoroethylene (manufactured by DuPont), FLARE (manufactured by Allied Chemical), etc., or any arbitrary combination thereof), semiconductor or optical element substrate materials (e.g., Al2O3, AlN, BeO, Cu, GaAS, GaN, Ge, InP, Si, SiO2, SiC, Si 1-x Ge x(0.0001 < x < 0.9999), or any combination thereof or an alloy), glass (e.g., 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 combination thereof), sapphire, polymer materials (e.g., polyamide, polyimide, polyester, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyphenylene sulfide, polyethersulfone, polyetherimide, polyetheretherketone, liquid crystal polymer, acrylonitrile-butadiene-styrene, or any compound, composite, or alloy thereof), leather, paper, assembly materials (e.g., Ajinomoto build-up film also known as "ABF"), solder resist, etc., or any composite, laminate, or other combination thereof is included.

[0019] Specific examples of workpieces that can be processed include panels of printed circuit boards (PCBs) (also referred to as "PCB panels" herein), PCBs, PCB laminates (such as FR4, high Tg epoxy, BT, polyimide, etc., or any combination thereof), PCB laminate prepregs, substrate-like PCBs (SLPs), panels of flexible printed circuits (FPCs) (also referred to as "FPC panels" herein), 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 (for example, substrates on which TFTs, color filters, organic LED (OLED) arrays, quantum dot LED arrays, etc., or any arbitrary combination thereof are formed), lenses, mirrors, turbine blades, powders, films, foils, plates, molds (such as wax molds, molds for injection molding processes and investment casting processes, etc.), fabrics (woven fabrics, felts, etc.), surgical instruments, medical implants, packaged products, shoes, bicycles, automobiles, automotive parts or aircraft parts (such as frames, body panels, etc.), appliances (such as microwave ovens, ovens, refrigerators, etc.), device housings (for example, for wristwatches, computers, smartphones, tablet computers, wearable electronic devices, etc., or any arbitrary combination thereof).

[0020] II. System - Overview FIG. 1 schematically shows a laser processing apparatus according to an embodiment of the present invention.

[0021] Referring to the embodiment shown in FIG. 1, a laser processing apparatus 100 (also simply referred to as "apparatus" herein) for processing a workpiece 102 can be characterized as including a laser source 104 for generating a laser energy beam, one or more positioners (for example, a first positioner 106, a second positioner 108, a third positioner 110, or any combination thereof), and a scan lens 112.

[0022] The laser energy that passes through the scan lens 112 and propagates along the beam path 116 propagates along the beam axis 118 so as to irradiate the workpiece 102. The laser energy propagating along the beam axis 118 can 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 can also be characterized as the shape of the laser energy beam (i.e., the cross-sectional shape, also referred to herein as the “spot shape”) propagating along the beam axis 118 (or the beam path 116), and the shape of this laser energy beam can be circular, elliptical, square, rectangular, triangular, hexagonal, ring-shaped, etc., or any shape. As used herein, the term “spot size” refers to the diameter or maximum spatial width of the laser energy beam irradiated at a position (also referred to as the “process spot”, “spot position” or more simply the “spot”) where an area of the workpiece 102 that is at least partially processed by the irradiated laser energy beam intersects the beam axis 118. In the discussion herein, the spot size is measured from the beam axis 118 to where the optical intensity is at least 1 / e of the optical intensity at the beam axis 118 2It is measured as the radial distance or the cross-sectional distance down to where it drops. Generally, the spot size of the laser energy beam is minimized at the beam waist. When irradiated onto the workpiece 102, the laser energy in the beam can be characterized as hitting the workpiece 102 with a spot size in the range of 2 μm to 200 μm. However, it can be understood that the spot size can be made smaller than 2 μm or larger than 200 μm. Thus, the laser energy beam irradiated onto the workpiece 102 can have a spot size larger than, smaller 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.

[0023] Generally, the above-described positioners (e.g., the first positioner 106, the second positioner 108, and the third positioner 110) are configured to change the relative position between the spot and the workpiece 102. Considering 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, it is optional to include the first positioner 106 (i.e., the apparatus 100 does not necessarily need to 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, it is optional to include the second positioner 108. Further, it should be understood that if the apparatus 100 includes the first positioner 106, the second positioner 108, or a combination thereof, it is optional to include the third positioner 110. Finally, it should be understood that, in appropriate cases, the apparatus 100 may include only the first positioner 106, only the second positioner 108, or only the third positioner 110.

[0024] The apparatus 100 also includes one or more optical elements (such as a beam expander, beam shaper, aperture, filter, collimator, lens, mirror, polarizer, waveplate, diffractive optical element, refractive optical element, etc., or any combination thereof) for focusing, expanding, collimating, shaping, polarizing, filtering, splitting, combining, cropping, or otherwise modifying, adjusting, and directing the laser energy beam obtained from the laser source 104 along one or more beam paths (such as beam path 116) leading to the scan lens 112. Such optical elements can be inserted at suitable or desired positions of the beam path 116 (such as 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, similar positions, or any combination thereof).

[0025] An example of such an optical element is a variable optical attenuator (VOA) configured to selectively and variably reduce the power of a laser pulse propagating along the beam path 116. Examples of VOA's that can be incorporated include one or more systems such as a variable neutral filter, an acousto-optic (AO) modulator (AOM), an AO deflector (AOD), a liquid crystal variable attenuator (LCVA), a VOA utilizing a microelectromechanical system (MEMS), an optical attenuator wheel, a polarization / waveplate filter, etc., or any combination thereof.

[0026] 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" means the diameter or width of the laser energy beam, measured from the beam axis 118, at which the optical intensity is 1 / e of the optical intensity along the propagation axis of the beam path 116 2It can be measured as the radial distance or the transverse distance down to a certain point. Examples of beam size adjustment mechanisms that can be incorporated include AOD systems, zoom lenses, motorized variable beam expanders, deformable mirrors, variable radius mirrors, variable focus moiré lenses, motorized Z-axis lenses, motorized iris diaphragms, motorized aperture wheels, etc., or any arbitrary combination thereof. By adjusting the beam size of the laser energy beam incident on the scan lens 112, the spot size on the workpiece 102 can be changed.

[0027] Another example of such an optical element is a beam shape adjustment mechanism that can selectively and variably adjust the shape (also referred to as "beam size" in this specification) of the laser energy beam incident on the scan lens 112. Examples of beam shape adjustment mechanisms that can be incorporated include AOD, deformable mirrors, variable radius mirrors, variable focus moiré lenses, etc., or any arbitrary combination thereof. By adjusting the beam shape of the laser energy beam incident on the scan lens 112, the spot shape on the workpiece 102 can be changed.

[0028] A. Laser Source In one embodiment, the laser source 104 can generate laser pulses. For this reason, the laser source 104 can include a pulsed laser source, a CW laser source, a QCW laser source, a burst mode laser, etc., or any combination thereof. When the laser source 104 includes a QCW laser source or a CW laser source, the laser source 104 can further include a pulse gating unit (e.g., an acousto-optic (AO) modulator (AOM), a beam chopper, etc.) 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 can 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 can be provided as a QCW laser source or a CW laser source and may not include a pulse gating unit. Thus, the laser source 104 can be broadly characterized as being capable of generating a laser energy beam that can be manifested as a series of laser pulses or as a continuous laser beam or a quasi-continuous laser beam. This laser energy beam can then propagate along the beam path 116. Although many of the embodiments described herein describe laser pulses, it should be understood that a continuous beam can be used instead or in addition, where appropriate.

[0029] Laser light having an electromagnetic spectrum in the UV range may have one or more wavelengths in the range from 10 nm (or around it) to 385 nm (or around it), such as 10 nm, 121 nm, 124 nm, 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, 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 from 500 nm (or around it) to 560 nm (or around it), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, or wavelengths between any of these values. Laser light having an electromagnetic spectrum in the IR range may have one or more wavelengths in the range from 750 nm (or around it) to 15 μm (or around it), such as from 600 nm to 1000 nm, 752.5 nm, from 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm, 1053 nm, 1060 nm, 1064 nm, 1080 nm, 1090 nm, 1152 nm, from 1150 nm to 1350 nm, 1540 nm, from 2.6 μm to 4 μm, from 4.8 μm to 8.3 μm, 9.4 μm, 10.6 μm, or wavelengths between any of these values.

[0030] The laser pulses output by the laser source 104 can have a pulse width or pulse duration (i.e., based on the full width at half maximum (FWHM) of the optical power in the pulse with respect to time) in the range from 10 fs to 900 ms. However, it can be understood that the pulse duration may be shorter than 10 fs or longer than 900 ms. Thus, at least one laser pulse output by the laser source 104 can have a pulse duration of 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, 20 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 a pulse duration shorter than a value between any of these values, longer than these values, or equal to these values.

[0031] The laser pulses output by the laser source 104 can have an average power in the range from 5 mW to 50 kW. However, it can be understood that the average power may be smaller than 5 mW or larger than 50 kW. Thus, the laser pulses output by the laser source 104 can have an average power of 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 an average power smaller than a value between any of these values, larger than these values, or equal to these values.

[0032] The laser source 104 can output laser pulses at a pulse repetition rate in the range of 5 kHz to 1 GHz. However, it can be understood that the pulse repetition rate may be lower than 5 kHz or higher than 1 GHz. Thus, the laser source 104 can output laser pulses at a pulse repetition rate of 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 at a pulse repetition rate lower than any value between these values, higher than these values, or equal to these values.

[0033] In addition to the wavelength, pulse duration, average power, and pulse repetition rate, the laser pulses irradiated on the workpiece 102 can be characterized by one or more other characteristics such as pulse energy, peak power, etc. This laser pulse can be selected (e.g., based on one or more other characteristics such as wavelength, pulse duration, average power, and pulse repetition rate as necessary) to irradiate the workpiece 102 at the process spot with an optical intensity (measured in W / cm 2 ), fluence (measured in J / cm 2 ) etc., sufficient to machine the workpiece 102 (e.g., to form one or more features having one or more desired characteristics).

[0034] Examples of types of lasers that can characterize the 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, passive mode-locked solid bulk or fiber lasers, dye lasers, mode-locked diode lasers, pulsed lasers (e.g., ms pulsed lasers, ns pulsed lasers, ps pulsed lasers, fs pulsed lasers), CW lasers, QCW lasers, etc., or any arbitrary combination thereof. Depending on the configuration, a gas laser (e.g., a carbon dioxide laser, etc.) may be configured to operate in one or more modes (e.g., CW mode, QCW mode, pulse mode, or any arbitrary combination thereof).Specific examples of laser sources that can be provided as laser source 104 include lasers of the BOREAS, HEGOA, SIROCCO, or CHINOOK series manufactured by EOLITE, lasers of the PYROFLEX series 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 manufactured by COHERENT, lasers of the ASCEND, ELEMENT 2, ELEMENT 2 CEP4, EXCELSIOR, EXPLORER, HIPPO, ICEFYRE, NAVIGATOR, QUANTA-RAY, QUASAR, SPIRIT, SPIRIT 1030-100, SPIRIT 1030-70, SPIRIT 515-50, TALON, or VGEN series manufactured by SPECTRA PHYSICS, lasers of the PULSTAR series or FIRESTAR series manufactured by SYNRAD, lasers of the TRUFLOW series (e.g., TRUFLOW 2000, 1700, 3000, 3200, 3600, 4000, 5000, 6000, 6000, 8000, 10000, 12000, 15000, 20000), lasers of the TRUCOAX series (e.g., TRUCOAX 1000) or lasers of the TRUDISK, TRUPULSE, TRUDIODE, TRUFIBER, or TRUMICRO series manufactured by TRUMPF, lasers of the FCPAμJEWEL or FEMTOLITE series manufactured by IMRA AMERICA, lasers of the TANGERINE and SATSUMA series (and oscillators of the MIKAN and T-PULSE series) manufactured by AMPLITUDE SYSTEMES. One or more laser sources such as lasers of 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, ULPR, VLM, VLPN, YLM, YLPF, YLPN, YLPP, YLR, YLS, FLPM, FLPMT, DLM, BLM, or DLR series manufactured by IPG Photonics Corporation (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.

[0035] B. First Positioner The first positioner 106 is disposed, positioned, or installed in the beam path 116 and is operative to diffract, reflect, refract, or otherwise act on, or any combination of, the laser pulse generated by the laser source 104 (i.e., "steer" the laser pulse) to deflect or move the beam path 116 (e.g., with respect to the scan lens 112), thereby deflecting or moving the beam axis 118 with respect to the workpiece 102. Generally, the first positioner 106 is operative to move the beam axis 118 with respect to the workpiece 102 along the X-axis (or X-direction), the Y-axis (or Y-direction), or a combination thereof (e.g., within a first scanning range projected onto the workpiece 102 by the scan lens 112). Although not shown, it will be understood that the X-axis (or X-direction) means an axis (or direction) orthogonal to the illustrated Y-axis (or Y-direction) and Z-axis (or Z-direction).

[0036] Generally, depending on one or more factors such as the configuration of the first positioner 106, the position 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 by a distance shorter than, longer than, or equal to a distance such as 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 in either the X direction or the Y direction. (For example, in the X direction or the Y direction, or in other directions) The maximum dimension of the first scanning range may be greater than, equal to, or less than the maximum dimension (measured in the XY plane) of the feature (such as an opening, a recess, a via, a trench, etc.) formed in the workpiece 102.

[0037] Generally, the speed at which the first positioner 106 can position the process spot at any position within the first scanning range (thereby moving the beam axis 118), also referred to herein as the "positioning speed", is in the range 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 can be 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 can be greater than, equal to, or less than a value between any of these values. The reciprocal of the positioning speed is referred to herein as the "positioning time" and means the shortest time required to change the position of the 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 longer than, equal to, or shorter 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.

[0038] The first positioner 106 can be a microelectromechanical system (MEMS) mirror or mirror array, an acousto-optic deflector (AOD) system, an electro-optic deflector (EOD) system, a first steering mirror (FSM) element incorporating (for example, a piezoelectric actuator, an electrostrictive actuator, a voice coil actuator, etc.), a galvanometer mirror system, a rotating polygon scanner, or the like, or any arbitrary combination thereof. In one embodiment, the first positioner 106 is provided as an AOD system including at least one (for example, one, two, three, four, etc.) single-element AOD system, at least one (for example, one, two, three, four, etc.) phased array AOD system, or any arbitrary combination thereof. The single-element AOD system and the phased array AOD system each include an AO cell formed of a material such as crystalline Ge, PbMoO4, or TeO2, glassy SiO2, quartz, As2S3, etc. As used herein, a "single-element" AOD system means an AOD system having only one ultrasonic transducer element acoustically coupled to the 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.

[0039] As will be understood by those skilled in the art, AO technology (e.g., AOD, AOM, etc.) utilizes the diffraction effect caused by sound waves propagating through an AO cell to modulate one or more characteristics of light waves (i.e., laser energy beams in the context of this application) that are simultaneously propagating through the AO cell. Typically, an AO cell can maintain both sound waves and light waves in the same region. The sound waves impart a perturbation to the refractive index within the AO cell. The sound waves are typically sent into the AO cell by driving ultrasonic transducer elements at one or more RF frequencies. By controlling the characteristics of the sound waves (e.g., amplitude, frequency, phase, etc.), one or more characteristics of the propagating light waves can be controllably modulated to move the beam path 116 (e.g., with respect to the scan lens 112). It should also be understood that the characteristics of the sound waves sent into the AO cell can be controlled using known techniques for attenuating the energy within the laser energy beam as it passes through the AO cell. Thus, the AOD system can also be operated to ultimately modulate the pulse energy of the laser pulses (and accordingly the fluence, peak power, light intensity, average power, etc.) that are incident on the workpiece 102.

[0040] 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) by deflecting the beam path 116, 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 along a combination thereof). Generally, the multi-axis AOD system can be a multi-cell system or a single-cell system. The multi-cell multi-axis system typically includes a plurality of AOD systems each capable of moving the beam axis along a different axis. For example, the multi-cell multi-axis system can include a first AOD system (e.g., an "X-axis AOD system") (e.g., a single-element or phased array AOD system) capable of moving the beam axis 118 along the X-axis and a second AOD system (e.g., a "Y-axis AOD system") (e.g., a single-element or phased array AOD system) capable of moving the beam axis 118 along the Y-axis. The 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-axis and the Y-axis. For example, the single-cell system can include at least two ultrasonic transducer elements acoustically coupled to orthogonal planes, facets, sides, etc. of a common AO cell.

[0041] C. Second Positioner The second positioner 108 is installed in the beam path 116 and operates to diffract, reflect, refract, or the like, or any combination thereof (i.e., "deflect" the laser pulse) on the laser pulse generated by the laser source 104 and passing through the first positioner 106, so as to deflect or move the beam path 116 (e.g., with respect to the scan lens 112), and as a result, deflect or move the beam axis 118 with respect to the workpiece 102. Generally, the second positioner 108 can move the beam axis 118 with respect to the workpiece 102 along the X-axis (or X-direction), Y-axis (or Y-direction), or a combination thereof (e.g., within a second scanning range projected onto the workpiece 102 by the scan lens 112).

[0042] Generally, depending on one or more factors such as the configuration of the second positioner 108, the position of the second positioner 108 along the beam path 116, the beam size of the laser pulse incident on the second positioner 108, the spot size, etc., the second scanning range may extend in either the X-direction or the Y-direction to a distance longer than the corresponding distance of the first scanning range. From the above perspective, the second scanning range may extend in either the X-direction or the Y-direction by a distance shorter than, longer 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-direction or Y-direction, or other directions) may be greater than, equal to, or smaller than the maximum dimension (measured in the XY plane) of the feature (e.g., aperture, recess, via, trench, scribe line, conductive trace, etc.) formed on the workpiece 102.

[0043] In the configuration described in this specification, it should be understood that 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. Thus, the second positioner 108 is operable to scan the first scanning range within the second scanning range.

[0044] Generally, the positioning speed at which the second positioner 108 can position the process spot at any position 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) extends over a range narrower than the first positioning bandwidth (also referred to herein as the "second positioning bandwidth"). In one embodiment, the second positioning bandwidth is in the range from 500 Hz (or around that) to 8 kHz (or around that). For example, the second positioning bandwidth can be 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 greater than, equal to, or less than any value between these values.

[0045] From the above perspective, it should be understood that the second positioner 108 can be a microelectromechanical system (MEMS) mirror or mirror array, an acousto-optic deflector (AOD) system, an electro-optic deflector (EOD) system, a first steering mirror (FSM) element (incorporating, for example, a piezoelectric actuator, an electrostrictive actuator, a voice coil actuator, etc.), a galvanometer mirror system, a resonant scanning mirror system, a rotating polygon scanner, or something similar, or any arbitrary combination thereof. In one embodiment, the second positioner 108 is a galvanometer mirror system including two galvanometer mirror elements, namely a first galvanometer mirror element (e.g., an X-axis galvanometer mirror element) configured to move the beam axis 118 relative to the workpiece 102 along the X-axis, and a second galvanometer mirror element (e.g., a Y-axis galvanometer mirror element) configured to move the beam axis 118 relative to the 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-axis and the Y-axis relative to the workpiece 102. In yet other embodiments, the second positioner 108 may be provided as a rotating polygon mirror system or the like. Thus, depending on the specific configurations of the second positioner 108 and the first positioner 106, it will be understood that the second positioning bandwidth may be equal to or greater than the first positioning bandwidth.

[0046] D. Third Positioner The third positioner 110 is operative to move the workpiece 102 relative to the scan lens 112, and as a result, to move the workpiece 102 relative to the beam axis 118. The movement of the workpiece 102 relative to the beam axis 118 is generally restricted such that the process spot can be scanned, moved, or positioned 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 to a distance greater than the corresponding distance of the second scanning range in either the X or Y direction. However, generally, the maximum dimension of the third scanning range (e.g., in the X or Y direction or other directions) is greater than the corresponding maximum dimension (measured in the XY plane) of the features formed on the workpiece 102. Optionally, the third positioner 110 may be adapted to move the workpiece 102 relative to the beam axis 118 within a scanning range extending in the Z direction (e.g., over a range from 1 mm to 50 mm). For this reason, the third scanning range may extend along the X, Y, and / or Z directions.

[0047] In the configuration described in this specification, it should be understood that the movement of the process spot with respect to the workpiece 102 (performed by the first positioner 106 and / or the second positioner 108) can be superimposed on the movement of the workpiece 102 performed by the third positioner 110. Thus, 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 at any position within the third scanning range (thereby moving the workpiece 102 and scanning the first scanning range within the third scanning range and / or further scanning the second scanning range within the third scanning range) extends over 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 lower than 500 Hz (or around it). For example, the third positioning bandwidth can be 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 a value less than any value between these values.

[0048] 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 about axes parallel to the X, Y, and / or Z directions respectively to the workpiece 102), similar ones, or any arbitrary 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 the X-axis stage (thereby being movable along the X direction by the X-axis stage) for moving the workpiece 102 along the Y direction.

[0049] Although not shown, the apparatus 100 may include a fixture (e.g., a chuck) coupled to the stage of the third positioner 110, if necessary. The fixture may include a support area within which the workpiece 102 can be mechanically clamped, adhered, held, fixed, or supported by the fixture. In one embodiment, the workpiece 102 can be clamped, adhered, held, fixed, or supported in direct contact with a typically flat main support surface of the fixture. In other embodiments, the workpiece 102 can be clamped, adhered, held, fixed, or supported so as to be spaced from the support surface of the fixture. In one embodiment, the workpiece 102 can be adhered, held, or fixed by a force (e.g., an electrostatic force, a vacuum force, a magnetic force) selectively applied to the workpiece 102 from the fixture or existing between the workpiece 102 and the fixture.

[0050] As described above, the apparatus 100 utilizes a so-called "stack type" positioning system in which the positions of components such as the first positioner 106, the second positioner 108, and the scan lens 112 are stationary within the apparatus 100 with respect to the workpiece 102 (e.g., via one or more supports, frames, etc. as is well known), and the third positioner 110 enables the workpiece 102 to be movable. In other embodiments, the third positioner 110 may be arranged and operable to move one or more components such as the first positioner 106, the second positioner 108, and the scan lens 112, and the workpiece 102 may be stationary.

[0051] In yet other embodiments, the third positioner 110 can be provided as a so-called "split stage" positioning system in which one or more components, such as the first positioner 106, the second positioner 108, the scan lens 112, or any combination thereof, are transported by one or more linear or rotational stages (provided on a frame, gantry, etc.), and the workpiece 102 is transported by one or more other linear or rotational stages. In such embodiments, the third positioner 110 includes one or more linear or rotational stages arranged and operable to move one or more components such as the second positioner 108 and the scan lens 112, and one or more linear or rotational stages arranged 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 stage positioning systems that can be beneficially or advantageously used in the apparatus 100 include any of those disclosed in U.S. Pat. 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, or any arbitrary combination thereof.

[0052] In one embodiment where the third positioner 110 includes a Z stage, the Z stage may be arranged and configured to move the workpiece 102 along the Z direction. In this case, the Z stage may be conveyed by one or more of the other stages described above for moving or positioning the workpiece 102, or the Z stage may convey one or more of the other stages described above for moving or positioning the workpiece 102, or any combination thereof. In other embodiments where the third positioner 110 includes a Z stage, the Z stage may be arranged and configured to move the scan lens 112 along the Z direction. Thus, when the third positioner 110 is provided as a split-axis positioning system, the Z stage may convey the X stage or may be conveyed by the X stage. By moving the workpiece 102 or the scan lens 112 along the Z direction, the spot size at the workpiece 102 can be changed.

[0053] In yet other embodiments, one or more components such as the first positioner 106, the second positioner 108, the scan lens 112, etc. may be conveyed by an articulated robotic arm (e.g., a 2-axis, 3-axis, 4-axis, 5-axis, or 6-axis arm). In such embodiments, the second positioner 108 and / or the scan lens 112 may be conveyed by the end effector of the robotic arm as needed. In yet other embodiments, the workpiece 102 may be conveyed directly on the end effector of the articulated robotic arm (i.e., without using the third positioner 110). In yet other embodiments, the third positioner 110 may be conveyed on the end effector of the articulated robotic arm.

[0054] D. Scan Lens Generally, a scan lens 112, provided as either a simple lens or a compound lens (for example), is configured to focus a laser pulse directed along a beam path to generate a beam waist that can typically be positioned at or near a desired process spot. The scan lens 112 can be provided as, for example, 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 arbitrary 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 (for example, a lens actuator, not shown) that is movable to vary the position of the beam waist along the beam axis 118 (for example). For example, the lens actuator may be provided as a voice coil capable of linearly translating the scan lens 112 along the Z direction. In this case, the scan lens 112 may be formed from materials such as fused silica, optical glass, zinc selenide, zinc sulfide, germanium, gallium arsenide, magnesium fluoride, and the like. In other embodiments, the scan lens 112 is provided as a variable focal length lens (for example, a zoom lens, or a so-called "liquid lens" incorporating technologies currently provided by companies such as COGNEX, VARIOPTIC, etc.) that can be actuated (for example, via a lens actuator) to vary the position of the beam waist along the beam axis 118. By varying the position of the beam waist along the beam axis 118, the spot size at the workpiece 102 can be varied.

[0055] In one embodiment, the scan lens 112 and the second positioner 108 are integrated into a common housing or “scan head”. Thus, in embodiments where the apparatus 100 includes a lens actuator, the lens actuator may be coupled to the scan lens 112 (e.g., such 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., such 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., such 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 scan head components or the scan head as a whole may be a modular assembly such that the scan head components can simply be removed and replaced with other components, or an entire scan head can simply be removed and replaced with another scan head.

[0056] E. Field of View The apparatus 100 may further include one or more cameras, such as a camera 113 (e.g., a CCD camera, a CMOS camera, or any combination thereof) having a field of view that encompasses the area occupied by the workpiece 102 supplied to the apparatus 100 for processing. The camera 113 may be coupled to the scan lens 112 or to the scan head described above. In other embodiments, when the third positioner 110 is a split stage positioning system, the camera 113 may be coupled to any stage that is arranged and operable to move the scan lens 112 or the scan head (instead of being coupled to the scan lens 112 or the scan head itself). In still other embodiments, the apparatus 100 may include a structure such as a frame or a gantry (collectively referred to herein as an "inspection support"). The camera 113 may be coupled to this inspection support. In this embodiment, the apparatus 100 may include one or more linear or rotary stages that are arranged and operable to move the inspection support (e.g., with respect to the workpiece 102), move the camera 113 (e.g., with respect to the inspection support), or perform similar or combined operations. The camera 113 can generate image data representing an image acquired within the field of view and output this image data to the controller 114 (e.g., as one or more image signals).

[0057] The image data can be analyzed, manipulated, input into algorithms, or processed by any desired or suitable known method (e.g., by the controller 114, by a remote system 126, or at any location that combines these), facilitating 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, or any combination thereof. To the extent that the image data is used to facilitate an inspection process (e.g., a visual inspection process), the camera (e.g., camera 113) that generated the image data can be considered part of an "inspection system". Thus, the inspection system can include a single camera or multiple cameras.

[0058] FIG. 1 illustrates the apparatus 100 as including only one camera 113, but it will be understood that there may be multiple cameras 113 (e.g., different in terms of resolution, field of view, or a combination thereof). For example, in one embodiment, the apparatus 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. Generally, the field of view of the second camera is located within the field of view of the first camera. However, the first camera and the second camera may be arranged such that the field of view of the second camera is located outside the field of view of the first camera. In addition, the camera 113 may have a field of view projected onto the workpiece 102. This field of view is larger than the first scanning range or the second scanning range.

[0059] Furthermore, although not shown, the apparatus 100 may include an illumination system (e.g., any suitable machine vision illumination system known in the art) capable of irradiating the field of view of the camera (e.g., camera 113).

[0060] In the illustrated embodiment, the camera 113 is laterally offset from the scan lens 112. Thus, the field of view of the camera 113 (projected onto the workpiece 102) may be located at least partially outside the scan field projected onto the workpiece 102 by the scan lens 112. In other embodiments, the apparatus 100 may include one or more optical components (e.g., one or more beam splitters, mirrors, lenses, etc., or any arbitrary combination thereof) that enable the field of view of the camera (e.g., camera 113) to be projected through the scan lens 112 by any method known in the art.

[0061] F. Controller Generally, device 100 includes one or more controllers, such as controller 114, to control device 100, or to facilitate the control of device 100, or to facilitate the operation of device 100. In one embodiment, controller 114 is communicatively coupled to one or more components of device 100, such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, (if a variable focal length lens) scan lens 112, fixture, camera 113, VOA, beam size adjustment mechanism, etc., 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. These one or more components of device 100 are operable in response to one or more control signals output by controller 114.

[0062] For example, controller 114 may control the operation of first positioner 106, second positioner 108, or third positioner 110 to effect relative movement between the beam axis and workpiece 102 and to cause relative motion between the process spot and workpiece 102 along a path or trajectory (also referred to herein as a "process track") within workpiece 102. In other examples, as will be described in more detail later, controller 114 may control the operation of third positioner 110 to effect relative movement between camera 113 and workpiece 102 after workpiece 102 has been processed to enable inspection of features formed in workpiece 102 as a result of the processing.

[0063] Generally, the controller 114 includes one or more processors capable of generating the control signals described above when executing instructions. The processor can be provided as a programmable processor capable of executing instructions (e.g., including one or more general-purpose computer processors, microprocessors, digital signal processors, etc., or any combination thereof). Instructions executable by the processor can be realized in the form of software, firmware, etc., or in a suitable form of circuitry including programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), field-programmable object arrays (FPOAs), application-specific integrated circuits (ASICs) (including digital circuits, analog circuits, analog / digital hybrid circuits), etc., or any combination thereof. Execution of the instructions may be performed on one processor, distributed among multiple processors, performed in parallel across multiple processors within one device or across a network of devices, or in a similar manner, or any combination thereof.

[0064] In one embodiment, the controller 114 includes a tangible medium such as a computer memory that is accessible by a 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 drive, etc.), optical disks, volatile or non-volatile semiconductor memories (e.g., RAM, ROM, NAND-type flash memory, NOR-type flash memory, SONOS memory, etc.), and may be locally accessible, or remotely accessible (e.g., via a network), or a 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.), and can be easily created by those skilled in the art from the descriptions set forth herein. Computer software is typically stored in one or more data structures transmitted by the computer memory.

[0065] Although not shown, one or more drivers (e.g., RF driver, servo driver, line driver, power supply, etc.) can be communicatively coupled to the inputs of one or more components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, (if a variable focal length lens) scan lens 112, 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, whereby controller 114 can generate one or more control signals (e.g., trigger signal, etc.). This control signal can be transmitted to the input of one or more drivers associated with one or more components of apparatus 100. Thus, components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, (if a variable focal length lens) scan lens 112, fixture, camera 113, VOA, beam size adjustment mechanism, etc. are adapted to respond to the control signals generated by controller 114.

[0066] In other embodiments, although not shown, one or more additional controllers (e.g., component-specific controllers) can be communicatively coupled to the inputs of drivers that are communicatively coupled to (and associated with) components such as laser source 104, first positioner 106, second positioner 108, third positioner 110, lens actuator, (if a variable focal length lens) scan lens 112, fixture, camera 113, VOA, beam size adjustment mechanism, etc. as needed. In this embodiment, each component-specific controller can be communicatively coupled to controller 114 and can generate one or more control signals (e.g., trigger signal, etc.) in response to one or more control signals received from controller 114. This one or more control signals can then be transmitted to the input of the driver communicatively coupled thereto. In this embodiment, the component-specific controller can operate in a manner similar to that described for controller 114.

[0067] In other embodiments where a component-specific controller for one or more of the components is provided, the component-specific controller associated with a certain component (e.g., the laser source 104) can be communicably coupled to the component-specific controller associated with a certain component (e.g., the first positioner 106, etc.). In this embodiment, one or more of the component-specific controllers can generate one or more control signals (e.g., a trigger signal, etc.) in response to one or more control signals received from one or more other component-specific controllers.

[0068] G. User Interface The apparatus 100 may further include a user interface 120 communicably coupled to the controller 114 via one or more wired or wireless serial or parallel communication links (such as, for example, USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any arbitrary combination thereof). The user interface 120 may include one or more output devices, one or more input devices, or any arbitrary combination thereof. Generally, an output device is any device capable of providing or transmitting information through a human-perceivable stimulus (such as, for example, visual, auditory, tactile, etc.). Examples of output devices include monitors, printers, speakers, tactile actuators, etc. Generally, an input device is any device that enables, for example, a user of the apparatus 100 to provide commands, commands, parameters, information, etc. for operating the apparatus 100 (or to simplify the operation of the apparatus 100). Examples of input devices include keyboards, mice, touch pads, touch screens, microphones, cameras, etc.

[0069] H. Communication Module Optionally, the apparatus 100 includes a communication module 122 communicatively coupled to the controller 114 via one or more wired or wireless serial or parallel communication links (such as, for example, USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof). The communication module 122 is adapted to transmit data, receive data, or both. Thus, the communication module 122 may include circuitry, antennas, connectors, etc., or combinations thereof, for transmitting and / or receiving data to / from other devices or networks (such as network 124) via wired or wireless links. In one example, the communication module 122 may be a connector that functions as a serial port (such as RS232), a universal serial bus (USB) port, an IR interface, etc., or any combination thereof, in cooperation with software or firmware within the controller 114. In other examples, the communication module 122 may be a universal interface driver application integrated circuit (UIDA) that supports multiple different host interface protocols such as RS-232C, IBM46XX, keyboard wedge interface, etc., or any combination thereof. The communication module 122 may include one or more modules, circuitry, antennas, connectors, etc., that support other known communication modes such as USB, Ethernet, Bluetooth, wifi, infrared (such as IrDa), RFID communication, etc., or any combination thereof, as known in the art. It will be understood that the communication module 122 may be incorporated as part of the controller 114 in a known or suitable manner, rather than as a separate component from the controller 114.

[0070] Network 124 can be communicatively coupled to one or more systems (e.g., remote system 126 as identified in FIG. 1) remote from device 100 via one or more wired or wireless serial or parallel communication links (such as, for example, USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, etc., or any combination thereof). In one embodiment, remote system 126 can be a device such as a computer (e.g., desktop computer, laptop computer, tablet computer, smartphone, etc.), a computing system (e.g., cloud computing platform), another controller or communication module (associated with another device such as device 100), or any combination thereof. It should be understood that remote system 126 can include a user interface including one or more output devices, one or more input devices, or any combination thereof, as illustratively described above with respect to user interface 120, or can be coupled thereto. Remote system 126 can be a device owned or operated by a user of device 100, or by the manufacturer of device 100, or by a technician responsible for performing maintenance on device 100, or the like, or any combination thereof.

[0071] Via communication module 122 and network 124, controller 114 can communicate various data with remote system 126. Thus, examples of data that can be output to remote system 126 include, for example, the above-described image data or measurement data (described in detail below), or any combination thereof. Data output by remote system 126 can be input to controller 114 (e.g., via network 124 and communication module 122) to represent instructions, commands, parameters, information, etc. for operating device 100 or for affecting or simplifying the operation of device 100.

[0072] I. Beam Characteristic Evaluation Tool Optionally, the apparatus 100 includes one or more beam characteristic evaluation tools, such as a beam characteristic evaluation tool 128 capable of measuring one or more characteristics of the laser energy beam. Examples of characteristics measurable by the beam characteristic evaluation tool 128 include the spatial energy distribution, phase, polarization, power, etc. at the spot of the incident laser energy beam irradiated on the beam characteristic evaluation tool 128, or any combination thereof. Accordingly, the beam characteristic evaluation tool 128 can 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. The beam characteristic evaluation tool 128 can generate measurement data representing one or more of the measured beam characteristics and output the measurement data to the controller 114 (e.g., as one or more measurement signals). Optionally, the measurement data (or data obtained from the measurement data by, for example, the controller 114) can be transmitted from the controller 114 to the remote system 126 (e.g., via the communication module 122 and the network 124).

[0073] As schematically shown in FIG. 1, the beam characteristic evaluation tool 128 can be configured and arranged to measure one or more characteristics of a laser energy beam (collectively also referred to herein as “beam characteristics”) by any method known in the art. For example, the beam characteristic evaluation tool 128 can measure one or more characteristics of the laser energy beam at a position where the workpiece 102 is processed by the laser energy beam or in the vicinity thereof (also referred to herein as the “process area”), as shown by, for example, arrow 128a, or at a position along the beam path 116 (i.e., the sampling position), or at a combined position thereof. In one embodiment, the sampling position may be between the second positioner 108 and the scan lens 112, as shown by, for example, arrow 128b, or between the first positioner 106 and the second positioner 108, or between the laser source 104 and the first positioner 106, or at a similar position thereto.

[0074] In other embodiments, the camera 113 (e.g., the first camera, the second camera, etc., or any combination thereof) can be operated to acquire an image of the spot at the workpiece 102, or at the fixture, or in the area outside the fixture, or at a similar position, or at a combined position thereof arbitrarily. In one embodiment, the acquired image may then be processed by the camera 113 such that the image data generated by the camera 113 represents the spatial energy distribution of the spot. In this case, the image data output by the camera 113 can be considered as “measurement data”, and the camera 113 can be considered as one embodiment of the beam characteristic evaluation tool 128.

[0075] J. Laser Sensor System In one embodiment, apparatus 100 includes a laser sensor system configured to measure laser energy or power. For example, this laser sensor system can be attached to the chuck and configured to measure the laser energy or power of the laser energy beam propagated from scan lens 112. In other examples, apparatus 100 can include one or more optical components disposed in beam path 116 and configured to divert a portion of the laser energy propagating along beam path 116 to the laser sensor system. In this example, the laser sensor system can be configured to measure the laser energy or power of the diverted portion of the laser energy. The 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), and this measurement data can be processed to support various operations 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 in the AOD system of first positioner 106 for RF power and frequency, etc.), or any combination thereof. Examples of operations that can be realized using the measurement data from the laser sensor system are described in U.S. Patent No. 7,244,906 mentioned above, or in U.S. Patent Application Publication Nos. 2014 / 0196140, 2014 / 0263201, or 2014 / 0263223 mentioned above, or in International Publication No. WO 2019 / 236616, or the like, or any combination thereof.

[0076] III. General Discussion on Data and Information The measurement data generated (e.g., as described above) can be processed to predict, obtain, recognize, or acquire one or more spatial characteristics of the laser energy beam, one or more energy characteristics of the laser energy beam, etc., or any combination thereof (e.g., automatically in the controller 114, or in the remote system 126, or in any combination of these).

[0077] Examples of measurable spatial characteristics include spatial energy distribution, spatial phase distribution, spatial polarization distribution, spot size, spot size, spot shape, spot direction, spot centroid, spot quality (represented by, for example, an M 2 parameter known in the art), etc., or any combination thereof. The spot shape can be measured, calculated, predicted, or determined using any known or suitable method (e.g., a known method for calculating roundness, circularity, etc.). For example, the roundness can be determined by the following formula.

Equation

[0078] Examples of energy specification include spot fluence, pulse energy (i.e., when 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-described characteristics, such as pulse energy (i.e., when the laser energy beam includes one or more laser energy pulses), average power, peak power, etc., or any combination thereof, may be used to facilitate the determination of energy characteristics such as spot fluence. Also, data representing one or more other characteristics, such as pulse duration or pulse repetition frequency (i.e., when the laser energy beam includes one or more laser energy pulses), may be used to facilitate the determination of one or more energy specifications. If such data is not generated as measurement data, it may be input to the controller 114 (e.g., via the user interface 120, communication module 122, etc.), or may be made accessible to the controller 114, remote system 126, etc., or any combination thereof.

[0079] Measurement data can be generated periodically, continuously, or before or after an event occurs, or at any combination of these timings (e.g., over a period of time, such as while the workpiece 102 is being processed). Examples of events that can trigger the generation of measurement data include the start of processing of the workpiece 102, the completion of processing of one or more workpieces 102, the operation of the apparatus 100 at a predetermined time, the operation of the laser source 104 at a predetermined time, etc., or any combination thereof. Other examples of events that can trigger the generation of measurement data include the receipt of an instruction to measure one or more beam characteristics (e.g., input via the user interface 120, remote system 126, etc., or any combination thereof).

[0080] When data representing spatial or energy characteristics of 1 or more (collectively referred to herein as "spot data") is predicted, obtained, recognized, or acquired from measurement data, this data can be analyzed, manipulated, input into an algorithm, or processed (automatically, for example, in controller 114, in remote system 126, or in any arbitrary combination thereof) to support 1 or more operations.

[0081] Measurement data, spot data, or other data (e.g., data representing pulse duration or pulse repetition frequency, data generated or acquired when performing test or inspection operations after the workpiece 102 is processed, the vacuum or air pressure and flow rate of the debris nozzle, the vacuum pressure of the fixture, the feedback of the position sensor associated with the second positioner 108 and / or the third positioner 110, the temperature and / or humidity within the process bay (generally, the process bay refers to the space where the workpiece 102 is placed during processing), etc., or any arbitrary combination thereof) representing one or more other characteristics of the apparatus 100. Other data such as the temperature and / or humidity in the ambient environment surrounding the apparatus 100, or any arbitrary combination thereof, may also be stored. It can be understood that data representing the temperature and / or humidity within the process bay, the temperature and / or humidity in the ambient environment, etc., can be generated by one or more known types of temperature sensors, humidity sensors, etc. Such sensors are generally shown comprehensively at 130 in FIG. 1. Other data that may be stored includes data representing the feedback signals associated with one or more positioners (e.g., the second positioner 108, the third positioner 110, etc., or any arbitrary combination thereof). Further other data can be obtained from and stored as measurement data, spot data, or any of the above-described data (e.g., by processing such data in the controller 114, in the remote system 126, or any arbitrary combination thereof). Examples of such obtained data include the total amount of laser energy irradiated during the formation of the feature, the average amount of laser energy per pulse irradiated during the formation of the feature (i.e., the total amount of laser energy irradiated during the formation of the feature divided by the number of pulses irradiated during the formation of the feature), the moving average amount of laser energy over n pulses (i.e., "n" can be set by the user or pre-determined, and is the moving average of the amount of laser energy irradiated during the formation of the feature divided by n pulses), etc.Other examples of input data include the presence of a positioning error (such as that caused by a positioner, e.g., the second positioner 108), the magnitude of the positioning error, or any arbitrary combination thereof, which can be obtained from a feedback signal associated with the positioner. All such stored data can be collectively referred to as "process control data".

[0082] Process control data may also include data representing one or more measured characteristics of the workpiece 102 measured (e.g., before, during, or after processing, or any arbitrary combination thereof). Examples of such data include the structure of one or more components of the workpiece 102 or the thickness of the entire workpiece, the surface quality of the workpiece 102 (e.g., the characteristics of surface defects such as scratches and pits), the reflectivity of the workpiece 102, the temperature of the workpiece 102, the distance from the scan lens 112 (or scan head) to the workpiece 102, or any arbitrary combination thereof. These characteristics can be measured in a region of the workpiece 102 before a feature is formed in that region, while a feature is being formed in that region, after a feature has been formed in that region, or at any arbitrary combination of these times. Examples of sensors known in the art that can be used to generate this process control data include cameras (e.g., having various illumination methods), laser displacement sensors, confocal laser sensors, interferometers, inductive coating thickness gauges, stylus profilometers, touch probes, or any arbitrary combination thereof. Such sensors are also generally shown at 130 in FIG. 1.

[0083] Generally, test or inspection operations can be performed by an automatic optical inspection (AOI) system, an automatic X-ray inspection (AXI) system, an in-circuit test (ICT) system, a wafer probe system, or the like. In one embodiment, the appearance inspection of the workpiece 102 can be performed by one or more cameras incorporated in the apparatus 100 (i.e., the "inspection system" described above).

[0084] Process control data can be stored in association with auxiliary information. Generally, the storage of process control data (relating to auxiliary information) is performed by using one or more databases. These databases may be present locally (e.g., in the computer memory of the controller 114 or on a computer memory accessible to the controller 114), or may be located at a location remote from the apparatus 100 (e.g., in the computer memory of the remote system 126 or on a computer memory accessible to the remote system 126), or similar thereto, or may be an arbitrary combination thereof.

[0085] Examples of auxiliary information that can be associated with process control data include the identity of device 100 (e.g., serial number, model number, etc.), the identity of workpiece 102 processed (or being processed) by device 100 (e.g., batch or lot number, serial number, model number, etc.), the identity (or position) of each feature formed (or being formed) on workpiece 102, the date and / or time when the process control was generated or acquired, etc., or information representing any arbitrary combination of these. For example, process control data obtained from measurement data generated when a first feature is formed during the processing of workpiece 102 (e.g., laser energy, peak power, average power, pulse repetition rate, spot size, etc., or data representing any arbitrary combination of these) can be associated with auxiliary information that uniquely identifies the first feature (or the position of the first feature on workpiece 102), and process control data obtained from measurement data generated when a second feature is formed in workpiece 102 (e.g., laser energy, peak power, average power, pulse repetition rate, spot size, etc., or data representing any arbitrary combination of these) can be associated with auxiliary information that uniquely identifies the second feature (or the position of the second feature on workpiece 102), and so on. The position of the feature formed on workpiece 102 can be identified based on information provided by the user or information generated by device 100 (e.g., a CAD file describing the process trajectory, or other tool path file, etc., or any arbitrary combination of these) and scale parameters formed from alignment points acquired by one or more cameras (e.g., camera 113).

[0086] Also, the auxiliary information may include "workpiece information" that describes one or more characteristics of the workpiece 102 existing before, during, after, or any combination thereof, of the workpiece 102 being processed. Examples of workpiece information include the material composition of the entire workpiece 102 with one or more component structures, lot number, panel number, thickness map, etc., or any combination thereof. Further, the auxiliary information may also include "application information" that describes the method by which the workpiece 102 is processed (or has been processed), the type of features formed on the workpiece 102, the location of the features formed on the workpiece 102, etc., or any combination thereof. The workpiece information and the application information may be provided by any suitable method (e.g., by the user interacting with the user interface 120, the remote system 126, etc., or any combination thereof). In certain embodiments, the workpiece information or the application information may be encoded by a machine-readable display (e.g., one or more markings that can be acquired and identified by a component of the device 100 such as the camera 113). In other embodiments, the machine-readable display may encode a link (e.g., a URL to a network resource including the workpiece information or the application information) that can be acquired and identified by a component of the device 100 such as the camera 113).

[0087] When the process control data is stored, this process control data may later be analyzed, manipulated, input into an algorithm, or processed (e.g., in the controller 114, in the remote system 126, or in any combination thereof) to support one or more operations. Examples of such operation embodiments are described in more detail in the section entitled "Directed Inspection" below.

[0088] A. Directed Inspection After processing the workpiece 102 to form a plurality of features (e.g., non-through via holes, through via holes, or combinations thereof) in the workpiece 102, any of the above-described process control data is processed (e.g., in relation to auxiliary information associated and stored therewith), and since the features to be inspected are relatively likely to have defects, such features can be identified. Generally, this process (hereinafter referred to as the "feature candidate selection" process) can be performed in the controller 114, in the remote system 126, or in any arbitrary combination thereof. In this specification, the features identified to be inspected are referred to as "feature candidates".

[0089] After the feature candidates are identified, the third positioner 110 can be operated so that each feature candidate moves into the field of view of the camera 113, and the camera 113 can be operated to acquire an image of each feature candidate located within its field of view. In this specification, the process of operating the third positioner 110 and the camera 113 to acquire an image of the feature candidate is referred to as "inspection". It can be understood that the time required to inspect only the feature candidates formed in the workpiece 102 is much shorter than the time required to inspect all the features formed in the workpiece 102. Also, by inspecting only the feature candidates instead of randomly sampling the features formed in the workpiece, it can be understood that the possibility of overlooking the area of the workpiece 102 including the defective features during inspection is reduced.

[0090] i. Additional Discussion on Feature Candidate Selection As described above, the feature candidate selection process is applied to process control data and related auxiliary information to identify feature candidates for inspection. In one embodiment, the feature candidate selection process applies one or more analysis methods and statistical thresholds (which can be determined experimentally or as a result of computer modeling or simulation), one or more machine learning algorithms, etc., or any combination thereof, to any of the process control data to predict or determine which of the processed features are relatively likely to be defective. It can be understood that one or more suitable analysis methods and machine learning algorithms known in the art can be implemented to simplify the feature candidate selection process.

[0091] An experienced and knowledgeable process engineer can develop an analysis method for this feature candidate selection process and set appropriate thresholds. However, by connecting such process control data, feature candidate selection processes, one or more inspection systems, one or more cameras (such as camera 113), etc., or any combination thereof, a learning feedback loop can be created automatically by using machine learning algorithms or by using manual offline statistical correlations by experienced personnel.

[0092] The feature candidate selection process can generate as output a data structure (such as a list) that includes the process control data or auxiliary information (including the identity or position of each feature within workpiece 102 or along the process trajectory) for each feature predicted or determined to be relatively likely to have a defect. It can be understood that the output of the predicted or determined likelihood for a feature can be saved in association with that feature as auxiliary information that can be used for later analysis, for traceability, etc., or for any combination of these purposes.

[0093] Optionally, certain aspects of the feature candidate selection process may be adjusted based on input from a user (e.g., provided via a user interface 120, a remote system 126, or any arbitrary combination thereof). For example, the user may specify how many features (e.g., in an absolute or relative sense) should be included in the output data structure. In other examples, the user may specify that features meeting an expected or determined criteria for being defective should be included in the output data structure.

[0094] a. Example of Embodiment Regarding Feature Candidate Selection In one embodiment, the feature candidate selection process may be applied to process control data that represents at least (e.g., in terms of total amount, average amount, etc., as described above) the laser energy propagated to the workpiece 102 (e.g., during the formation of each feature, during a specific process of forming each feature, or among any combination thereof). In this case, the statistical thresholds that may be used when analyzing the process control data may include thresholds such as positive or negative maximum laser energy deviations (e.g., with respect to one or more predetermined set values based on one or more relevant workpiece information and / or application information). Generally, when the total amount or average amount of laser energy propagated during the formation of a feature (or during a specific process of forming the feature) exceeds the positive maximum laser energy deviation, the feature finally formed is likely to have defects because the laser energy used to form the feature is excessive. Features formed with excessive laser energy (e.g., non-through via holes, trenches, recesses, etc.) may cause the material exposed to the feature or the material near the feature to be damaged to an unacceptable extent (e.g., melted, ablated, cracked, etc.), or the feature itself may have an unacceptable size or shape, an unacceptable taper, overhang, etc., or any combination thereof, and thus can be regarded as having defects. Similarly, when the total amount or average amount of laser energy propagated during the formation of a feature (or during a specific process of forming the feature) exceeds the negative maximum laser energy deviation, the feature finally formed is likely to have defects because the laser energy used to form the feature is insufficient. Features formed with insufficient laser energy (e.g., non-through via holes, trenches, recesses, etc.) can be regarded as having defects because sufficient material required to form the required feature is not removed from the workpiece 102.

[0095] ii. Additional Discussion on Inspection The position of each feature candidate identified in the output of the feature candidate selection process can be used to control the operation of the third positioner 110 during inspection. In one embodiment, offsets (e.g., in the X and / or Y directions) can be applied to each position to compensate for the lateral offset between the field of view of the camera 113 projected onto the workpiece 102. Generally, the operation of the third positioner 110 can be controlled during inspection to cause relative movement between the workpiece 102 and the camera 113 (i.e., the field of view of the camera projected onto the workpiece 102) along a path or trajectory (also referred to herein as an "inspection trajectory") that can be calculated based on the output of the feature candidate selection process (e.g., in the controller 114, in the remote system 126, or in any combination thereof). In one embodiment, the inspection trajectory used to inspect the features formed during the machining of the workpiece 102 corresponds to the process trajectory used to form the features during the machining of the workpiece 102. In other embodiments, the inspection trajectory does not correspond to the process trajectory used to form the features during the machining of the workpiece 102. In this case, the inspection trajectory can represent an optimized path or route that enables the camera 113 to acquire an image of each feature candidate in the machined workpiece 102.

[0096] During the inspection, the image data generated by the camera 113 (i.e., the data representing the image acquired within its field of view) is output to the controller 114 (e.g., as one or more image signals), and then analyzed, operated on, input into an algorithm, or processed in a desired or suitable manner known in the art (e.g., by the controller 114, by the remote system 126, by the user, or by a similar method, or by any arbitrary combination thereof) to determine whether the feature part is properly formed (i.e., whether it has defects). It can be understood that the image data representing the acquired image of the feature part candidate can be stored in association with the feature part as auxiliary information that can be used for later analysis, for traceability, or for any arbitrary combination of these purposes.

[0097] a. Manual Aspects Associated with Directed Inspection and Classification In one embodiment, the third positioner 110 can be manually operated (e.g., via user interaction through the user interface 120, user interaction through the remote system 126, or any arbitrary combination thereof) so that each feature part candidate moves into the field of view of the camera 113, and the camera 113 can be operated (e.g., via user interaction through the user interface 120, user interaction through the remote system 126, or any arbitrary combination thereof) to acquire an image of each feature part candidate located within its field of view. The acquired image can be displayed (e.g., by a monitor of the user interface 120, the remote system 126, or any arbitrary combination thereof). The user can manually classify the feature parts (e.g., via an input device such as the user interface 120 or the remote system 126) as defective or non-defective in association with the displayed image.

[0098] b. Automated Aspects Associated with Directed Inspection and Classification In other embodiments, the operations of the third positioner 110 and the camera 113 can be automatically performed (e.g., by the controller 114, the remote system 126, or any arbitrary combination thereof) to inspect and classify each feature candidate. In this embodiment, the image data generated as a result of the inspection can be processed using any suitable image recognition technique in order to classify the inspected features as, for example, defective or non-defective. When the third positioner 110 is operating to move the feature candidate into the field of view of the camera 113, an image can be acquired after the operation of the third positioner 110 has stabilized and the feature candidate has come to rest within the field of view of the camera 113, or at any arbitrary combination of these timings.

[0099] c. Semi - Automated Aspects Associated with Directed Inspection and Classification In still other embodiments, the operations of the third positioner 110 and the camera 113 can be performed semi-automatically to inspect and classify each feature candidate. In this embodiment, the third positioner 110 is operated (e.g., by the controller 114, the remote system 126, or any arbitrary combination thereof) to cause the camera 113 to acquire an image of each feature candidate. The acquired image can then be displayed (e.g., by the monitor of the user interface 120, the remote system 126, or any arbitrary combination thereof). The user can manually classify the features (e.g., via an input device such as the user interface 120 or the remote system 126) as, for example, defective or non-defective, in association with the displayed image. An example of the process for the manual classification of the feature candidates entered will be described in more detail below with respect to Figure 2.

[0100] In FIG. 2, a process such as process 200 can be executed to facilitate the manual classification of feature candidates. Referring to FIG. 2, at S202, an image of an unclassified feature candidate to be inspected is displayed to the user (e.g., via user interface 120, via the user interface of remote system 126, etc.). Optionally, other information regarding the feature candidate, other information regarding the identity or location of the feature candidate within workpiece 102 is also displayed to the user (e.g., via user interface 120, via the user interface of remote system 126, etc.). At S204, the user is prompted (e.g., via user interface 120, via the user interface of remote system 126, etc.) to indicate whether they want to classify the currently displayed feature candidate. If the user agrees to classify the feature candidate, at S206, the user classifies the feature candidate (e.g., as "defective" or "non-defective") based on the displayed image (e.g., via user interface 120, via the user interface of remote system 126, etc.). If unclassified feature candidates remain, the process described above is repeated. At S208, the user is prompted (e.g., via user interface 120, via the user interface of remote system 126, etc.) to indicate whether they want to classify any other unclassified feature candidates. If any other unclassified feature candidates are inspected, the process described above is repeated for the new unclassified feature candidates. At S208, if no unclassified feature candidates remain, the process ends. At S204, if the user indicates (e.g., via user interface 120, via the user interface of remote system 126, etc.) that they do not want to classify the currently displayed feature candidate, the process proceeds to S208.

[0101] iii. Other Aspects Regarding Directed Inspection It should be understood that information regarding the classification of the inspected feature part candidates, whether manually or automatically classified, can be stored in association with the feature part as auxiliary information that can be used for subsequent analysis, for traceability, etc., or for any purpose that combines these arbitrarily.

[0102] The above-described embodiments have described how the output of the feature part candidate selection process can be used to control the operation of the apparatus 100 (e.g., the third positioner 110, the camera 113, or a combination thereof) during inspection. However, in other embodiments, the output of the feature part candidate selection process can be an input to an inspection system (also referred to as a "remote inspection system") that is not part of the apparatus 100 (e.g., as described above). Examples of remote inspection systems capable of inspecting the identified feature part candidates include AOI, AXI systems, ICT systems, wafer probe systems, etc., or any combination thereof.

[0103] In one embodiment, the remote inspection system is an embodiment of the remote system 126, and thus, the controller 114 can transmit the output of the feature part candidate selection process to the remote inspection system (i.e., the remote system 126) via the network 124. However, in other embodiments, the controller 114 can write the output of the feature part candidate selection process to any machine-readable medium (e.g., a flash drive inserted into the USB port of the communication module 122), or transmit the feature part candidate selection that can record its output on a suitable or desired machine-readable medium (e.g., a flash drive) connected to the remote system 126 to another system (e.g., the remote system 126). Thereafter, the output of the feature part candidate selection stored by the machine-readable medium can be input to the remote inspection system by any suitable or desired method.

[0104] XIII. Conclusion The above has described embodiments and examples of the present invention and should not be construed as being limited thereto. Although some specific embodiments and examples have been described with reference to the drawings, those skilled in the art will readily recognize that many improvements can be made to the disclosed embodiments and examples and other embodiments without departing significantly from the novel teachings and advantages of the present invention. Accordingly, all such improvements 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 the subject matter of some or all of the other sentences, paragraphs, examples or embodiments, except where such combinations are mutually exclusive. Therefore, the scope of the present invention should be determined by the following claims and the equivalents of the claims that should be included therein.

Claims

1. A laser processing apparatus for forming a feature portion on a workpiece, comprising: a laser source capable of generating a laser energy beam; a scan lens arranged so as to be able to focus the laser energy beam so that the focused laser energy beam can propagate to the workpiece; at least one beam positioner arranged between the laser source and the scan lens and capable of scanning the focused laser energy beam with respect to the workpiece within a scanning range projected onto the workpiece by the scan lens; at least one stage capable of causing relative movement between at least one selected from the group consisting of the workpiece, the scan lens, and the camera; a camera having a field of view and capable of acquiring an image of an object within the field of view; at least one sensor capable of generating process control data representing at least one selected from the group consisting of: a) at least one characteristic of the apparatus either before, during, or after the workpiece is processed to form a set of feature portions; b) at least one characteristic of the workpiece either before, during, or after the workpiece is processed to form a set of feature portions; and c) at least one characteristic of the surrounding environment in which the apparatus is located either before, during, or after the workpiece is processed to form a set of feature portions; a controller communicably connected to one or more databases in which process control data is stored in association with auxiliary information representing the positions of the at least one stage, the camera, and the respective feature portions formed on the workpiece; and the controller is capable of executing or facilitating the execution of a feature portion candidate selection process, whereby the process control data is processed to predict whether any of the feature portions formed on the workpiece have defects, and the positions of the feature portions predicted to have defects are identified. The apparatus.

2. The apparatus according to claim 1, wherein the controller is capable of executing at least a part of the candidate selection process.

3. The apparatus according to any one of claims 1 or 2, further comprising a communication module communicably connected to the controller and capable of transmitting data.

4. The apparatus according to claim 3, wherein the controller is capable of transmitting the output of the candidate selection process to a remote system via the communication module.

5. The apparatus according to claim 4, wherein the remote system is a remote inspection system, and the output of the candidate selection process is in a format readable by the remote inspection system.

6. The apparatus according to claim 3, wherein the controller is capable of promoting the execution of the feature candidate selection process by transmitting at least a part of the process control data to a remote system via the communication module.

7. The apparatus according to claim 6, wherein the remote system includes at least one computing system.

8. The apparatus according to any one of claims 3 to 4, 6, and 7, wherein the communication module is capable of receiving data, and the controller is capable of receiving at least a part of the output of the feature candidate selection process from the remote system via the communication module.

9. The apparatus according to any one of claims 1 to 8, further comprising at least one of the one or more databases.

10. The apparatus according to any one of claims 3 to 9, wherein the controller is capable of transmitting at least a part of the process control data to at least one of the one or more databases via the communication module.

11. The apparatus according to any one of claims 1 to 10, wherein the field of view of the camera is within a scan field that can be projected onto the workpiece by the scan lens.

12. The apparatus according to any one of claims 1 to 11, wherein the field of view of the camera is at least partially outside the scan field that can be projected onto the workpiece by the scan lens.

13. The apparatus according to any one of claims 1 to 12, further comprising a frame arranged to direct the scan lens with respect to the workpiece, and the scan lens is connected to the frame.

14. The apparatus according to claim 13, further comprising a stage connected between the frame and the scan lens, and the stage is capable of moving the scan lens.

15. The apparatus according to any one of claims 13 to 14, wherein the camera is connected to the scan lens.

16. The camera is the device according to claim 14, which is connected to the stage.

17. The camera is the device according to claim 13, which is connected to the frame.

18. The device further comprises an inspection support portion arranged to support the camera with respect to the workpiece, and the camera is the device according to any one of claims 1 to 17, which is connected to the inspection support portion.

19. The device according to claim 17, further comprising a stage connected to the inspection support portion and movable with respect to the workpiece.

20. The device according to any one of claims 18 to 19, further comprising a stage connected between the inspection support portion and the camera, and the stage is movable with respect to the inspection support portion for the camera.

21. The device according to any one of claims 1 to 20, wherein the controller is capable of controlling the operation of the at least one stage and the camera to perform inspection operations at specific respective positions.

22. The device according to any one of claims 1 to 21, wherein the controller is further capable of controlling the operation of the at least one stage and the camera based on user input received at the user interface to perform inspection operations at specific respective positions.

23. The device according to any one of claims 1 to 22, wherein the controller is further capable of controlling the operation of the at least one stage and the camera based on data received from a remote system via the communication module to perform inspection operations at specific respective positions.

24. The device according to any one of claims 1 to 23, wherein the at least one sensor includes at least one selected from the group consisting of a laser power meter and a beam characteristic determination tool.

25. The device according to any one of claims 1 to 24, wherein the at least one sensor includes at least one selected from the group consisting of a temperature sensor and a humidity sensor.

26. The device according to any one of claims 1 to 25, wherein the at least one sensor includes at least one selected from the group consisting of a camera, a laser displacement sensor, a confocal laser sensor, an interferometer, an eddy current coating thickness gauge, a stylus profilometer, and a touch probe.

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