Laser machining apparatus facilitating guided detection of laser machined workpieces and method of operation thereof

Abstract

A laser processing apparatus for forming features in a workpiece includes at least one sensor for generating process control data representative of: a) at least one characteristic of the apparatus before, during or after processing the workpiece to form a set of features; b) at least one characteristic of the workpiece before, during or after machining 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 before, during or after machining the workpiece to form a set of features. A controller executes or facilitates execution of a candidate feature selection process whereby process control data is processed to estimate whether any of the features formed in the workpiece is defective, and identifies a location of any feature that is estimated to be defective.

Description

[0001] This case is a divisional application of the invention patent application with the application date of March 10, 2021, the priority date of May 14, 2020, the application number 202180018781.5, and the invention name "Laser processing equipment and method of operation for promoting guided detection of laser processed workpieces". Technical Field

[0002] Embodiments disclosed herein generally relate to laser processing apparatus and methods for laser processing a workpiece. Background Art

[0003] Laser processing can be performed on a variety of different workpieces using a variety of lasers performing a variety of processes. For example, laser micromachining processes have been developed to form features such as through-holes or blind vias in workpieces such as printed circuit boards (PCBs) or integrated circuit (IC) packages. The goal of laser micromachining processes is to provide consistent feature quality across the entire workpiece. Some metrics that define feature quality include the location, size, and shape of the feature. Other metrics may include sidewall angle, bottom texture, and the volume and texture of debris remaining in the feature after machining.

[0004] One issue with laser micromachining processes is that performing the micromachining process with the same laser parameters at two different locations on a workpiece can result in variations in feature quality due to non-uniformities in the workpiece. Examples of workpiece variations that can affect the results include thickness variations, workpiece flatness variations, and surface preparation variations, which can cause the workpiece to reflect more or less laser power. These variations are not constant across the workpiece and can vary depending on the location of individual features. Furthermore, due to normal variations in manufacturing tolerances, these variations can be reproducible between workpieces within a given batch of workpieces.

[0005] Other phenomena that can affect the ability of a laser micromachining system to form features of consistent 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 to the workpiece. As a laser source ages, its ability to output laser energy with consistent characteristics (e.g., average power) may decrease. Furthermore, as the optical components age, they become susceptible to contamination, particularly from debris from the micromachining process itself, and damage from the high-power laser energy transmitted through them. These and other forms of degradation can cause changes in the size, shape, intensity, or other characteristics of the laser spot projected on the workpiece, thereby changing the size, shape, depth, or other measurements of the micromachined features.

[0006] Some laser micromachining systems use real-time control to modify the characteristics of the laser energy beam as features are machined 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 light detector is used to monitor the laser power as the workpiece is machined. The output from the light detector is used to adjust the laser power incident on the workpiece in real time to compensate for some sources of variability in the laser power at the workpiece. This can be achieved by operating optical components such as variable attenuators to adjust the amount of laser energy ultimately delivered to the workpiece to a level appropriate for forming each feature.

[0007] It is known to record information about the characteristics of the laser energy beam used to form each feature in a workpiece and associate the information with an identifier that identifies the location of the feature in the workpiece (e.g., thereby creating "process data"). After the workpiece is processed, the generated process data can be analyzed to predict when the laser micromachining system is having problems forming features of suitable quality. For example, if the recorded information indicates that the system may require more laser power than is available, then features formed with less laser power may not remove enough material.

[0008] It is also known to inspect processed workpieces to assess the quality of formed features. Inspection results can be compared with process data (if generated) to assess the effectiveness of the characteristics of the laser energy beam used to form the features in the workpiece. Post-process inspection, such as that performed on workpieces such as PCBs, can be performed manually (e.g., by a user inspecting the workpiece using a microscope) or automatically (e.g., by automated optical inspection (AOI)). If inspection is performed manually, the features inspected (e.g., through-holes) constitute only a sample of the total number of features formed, as workpieces often have hundreds or thousands of features formed therein. If inspection is performed by AOI, all features in a batch of one or more workpieces can be inspected immediately after feature formation (e.g., when the features are through-holes) or after post-processing steps are performed to clean the features (e.g., when the features are blind holes, desmearing, etching, and shadowing steps are performed to remove debris within the holes).

[0009] Conventional post-process inspection techniques can be problematic for a number of reasons. With manual inspection, operators or quality inspectors using microscopes can become fatigued, potentially leading to defects being missed when attention is reduced. When inspecting all features (e.g., using AOI techniques), it's unnecessary to spend extra time inspecting areas of the workpiece where defective features are less likely to form. When inspecting features randomly, there's a risk that some areas of the workpiece more likely to have defective features will go undetected, causing missed quality issues that can lead to scrapped workpieces. Summary of the Invention

[0010] One embodiment of the present invention can be broadly characterized as a laser processing apparatus for forming features in a workpiece. The apparatus may include: a laser source operable to generate a beam of laser energy; a scan lens configured to focus the laser energy beam so that the focused laser energy beam can be delivered to the workpiece; at least one beam positioner disposed between the laser source and the scan lens, the at least one beam positioner operable to scan the focused laser energy beam relative to the workpiece within a scan range projected onto the workpiece via the scan lens; at least one stage operable to impart relative movement between the workpiece and at least one selected from the group consisting of the scan lens and a camera; the camera having a field of view and operable to capture an image of an object within the field of view; and at least one sensor. A device operable to generate process control data representing at least one selected from the group consisting of: a) at least one characteristic of the equipment before, during, or after processing the workpiece to form a set of features; b) at least one characteristic of the workpiece before, during, or after processing the workpiece to form the set of features; and c) at least one characteristic of an environment surrounding the equipment before, during, or after processing the workpiece to form the set of features; and a controller communicatively coupled to at least one stage, the camera, and one or more databases storing process control data in association with auxiliary information, wherein the auxiliary information represents a location of each feature to be formed in the workpiece. The controller is operable to perform or facilitate performance of a candidate feature selection process whereby: the process control data is processed to estimate whether any of the features formed in the workpiece is defective; and the location of any feature estimated to be defective is identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A laser processing apparatus according to an embodiment of the present invention is schematically described.

[0012] Figure 2 An example process for collecting manually input classification of candidate features according to one embodiment of the present invention is described. DETAILED DESCRIPTION

[0013] Example embodiments are described herein with reference to the accompanying drawings. Unless expressly stated otherwise, the sizes, positions, and any distances between components, features, elements, and the like in the drawings are not necessarily to scale but are exaggerated for clarity. Throughout the drawings, identical reference numerals refer to identical elements. Therefore, identical or similar reference numerals may be used in reference to other drawings, even if those reference numerals are not mentioned or described in the corresponding drawings. Furthermore, even elements not designated by reference numerals may be described with reference to other drawings.

[0014] The terms used herein are only used to describe the purpose of specific exemplary embodiments and are not intended to be restrictive. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art. As used herein, unless the context clearly indicates otherwise, the singular forms "a / an" and "the" are intended to also include plural forms. It should be recognized that the term "comprising" when used in this specification specifies the presence of stated features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof. Unless otherwise specified, when describing a value range, the value range includes both the upper and lower limits of the range and any sub-ranges therebetween. Unless otherwise indicated, terms such as "first", "second", etc. are only used to distinguish one element from another. For example, a node may be referred to as a "first node", and similarly, another node may be referred to as a "second node", or vice versa.

[0015] Unless otherwise indicated, the terms "about," "approximately," and the like mean that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller as necessary to reflect tolerances, conversion factors, rounding, measurement errors, and the like, as well as other factors known to those skilled in the art. For ease of description, spatially relative terms such as "below," "beneath," "lower," "above," and "upper," and the like, may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the drawings. It should be recognized that these spatially relative terms are intended to encompass different orientations in addition to the orientation depicted in the drawings. For example, if the object in the drawings is turned over, an element described as "below" or "beneath" other elements or features would be oriented "above" the other elements or features. Thus, the exemplary term "below" may encompass both above and below orientations. Objects may be otherwise oriented (eg, rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0016] The section headings used herein are for organizational purposes only, and unless expressly stated otherwise, these section headings should not be construed as limiting the subject matter described. It should be understood that many different forms, embodiments, and combinations are possible without departing from the spirit and teachings of the present invention, and therefore, the present invention should not be considered limited to the example embodiments set forth herein. Rather, these examples and embodiments are provided so that this disclosure will be thorough and complete, and will convey the scope of the invention to those skilled in the art.

[0017] Overview

[0018] The embodiments described herein generally relate to methods and apparatus for laser processing (or, more simply, "processing") a workpiece. Processing is generally accomplished in whole or in part by irradiating the workpiece with laser radiation to heat, melt, vaporize, ablate, crack, discolor, polish, roughen, carbonize, foam, or otherwise modify one or more properties or characteristics of one or more materials forming the workpiece (e.g., in terms of chemical composition, atomic structure, ionic structure, molecular structure, electronic structure, microstructure, nanostructure, density, viscosity, refractive index, magnetic permeability, relative permittivity, texture, color, hardness, transmittance of electromagnetic radiation, or the like, or any combination thereof). The material to be processed may be external to the workpiece before or during processing, or may be entirely within the workpiece (i.e., not external to the workpiece) before or during processing.

[0019] Specific examples of processes that can be performed by the disclosed apparatus for laser processing include drilling or other hole formation, cutting, perforating, welding, scribing, engraving, marking (e.g., surface marking, subsurface marking, etc.), laser-induced forward transfer, cleaning, bleaching, bright pixel repair (e.g., color filter darkening, OLED material modification, etc.), coating removal, surface texturing (e.g., roughening, smoothing, etc.), or the like, or any combination thereof. Thus, as a result of processing, one or more features that can be formed on or in a workpiece can include openings, slots, through-holes or other holes, recesses, grooves, scribe lines, saw cuts, recessed areas, conductive traces, ohmic contacts, photoresist patterns, artificial or machine-readable markings (e.g., consisting of one or more regions in or on a workpiece having one or more visually or texturally distinguishable characteristics), or the like, or any combination thereof. When viewed from a top plan view, features such as openings, slots, through-holes, and holes can have any suitable or desirable shape (e.g., circular, oval, square, rectangular, triangular, annular, or the like, or any combination thereof). Furthermore, features such as openings, slots, through-holes, and holes can extend completely through the workpiece (e.g., to form a so-called "through via," "through hole," etc.) or only partially through the workpiece (e.g., to form a so-called "blind via," "blind hole," etc.).

[0020] A generally characteristic feature of a workpiece that can be processed can be formed from one or more metals, polymers, ceramics, composites, or any combination thereof (e.g., whether alloy, compound, mixture, solution, 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 or the like or any combination thereof (e.g., whether alloy, composite, etc.); conductive metal oxides (e.g., ITO, etc.); transparent conductive polymers; ceramics; waxes; resins; interlayer dielectric materials (e.g., silicon dioxide, silicon nitride, silicon oxynitride, etc., low-k dielectric materials, such as methyl silsesquioxane (MSQ), hydrogen silsesquioxane (HSQ), fluorinated tetraethyl orthosilicate (FTEOS) or the like or any 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 the like or any combination thereof); semiconductor or optical device substrate materials (e.g., Al2O3, AlN, BeO, Cu, GaAS, GaN, Ge, InP, Si, SiO2, SiC, Si 1-x Ge x (where 0.0001 < x < 0.9999) or the like or any combination or alloy); glass (e.g., fused quartz, soda-lime-silica glass, borosilicate glass, lead oxide glass, aluminosilicate glass, germanium oxide glass, aluminate glass, phosphate glass, borate glass, chalcogenide glass, amorphous metal or the like or any combination thereof); sapphire; polymers (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 of its compounds, composites or alloys); leather; paper; build-up materials (e.g., Ajinomoto build-up film, also known as "ABF", etc.); solder mask; or the like or any composite, laminate or other combination.

[0021] Specific examples of workpieces that can be processed include a panel of a printed circuit board (PCB) (also referred to herein as a "PCB panel"); a PCB; a PCB laminate (e.g., FR4, high Tg epoxy, BT, polyimide, or the like, or any combination thereof); a PCB laminate prepreg; a substrate-like PCB (SLP); a panel of a flexible printed circuit (FPC) (also referred to herein as an "FPC panel"); an FPC; a cover film; an integrated circuit (IC); an IC substrate; an IC package (ICP); a light-emitting diode (LED); a substrate-like PCB (SLP); a flexible printed circuit (FPC); a cover film; an integrated circuit (IC); an IC substrate; an IC package (ICP); a light-emitting diode (LED); a substrate-like PCB (SLP); a cover film; an integrated circuit (IC); an IC substrate; an IC package (ICP); a light-emitting diode (LED ... diode; LED); LED package; semiconductor wafer; electronic or optical device substrate; interposer; lead frame; lead frame sheet; display substrate (e.g., a substrate having formed thereon a TFT, a color filter, an organic LED (OLED) array, a quantum dot LED array, or the like, or any combination thereof); lens; mirror; turbine blade; powder; film; foil; plate; mold (e.g., a wax mold, a mold for an injection molding process, an overmolding process, etc.); fabric (woven fabric, felt, etc.); surgical instrument; medical implant; consumer packaged goods; shoe; bicycle; automobile; motor vehicle or aviation part (e.g., a frame, a body panel, etc.); appliance (e.g., a microwave oven, an oven, a refrigerator, etc.); device housing (e.g., for a watch, a computer, a smartphone, a tablet computer, a wearable electronic device, or the like, or any combination thereof).

[0022] II. System Overview

[0023] Figure 1 A laser processing apparatus according to an embodiment of the present invention is schematically described.

[0024] refer to Figure 1 In the embodiment shown in FIG, a laser processing apparatus 100 (also referred to herein simply as “apparatus”) for processing a workpiece 102 can be characterized as including a laser source 104 for generating a laser energy beam, one or more positioners (e.g., a first positioner 106, a second positioner 108, a third positioner 110, or any combination thereof), and a scanning lens 112.

[0025] The laser energy transmitted along the beam path 116 through the scan lens 112 propagates along the beam axis 118 for delivery to the workpiece 102. The laser energy propagating along the beam axis 118 can be characterized as having a Gaussian-type spatial intensity profile or a non-Gaussian-type (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 by the shape (i.e., cross-sectional shape, also referred to herein as "spot shape") of the laser energy beam propagating along the beam axis 118 (or beam path 116), which can be circular, elliptical, square, rectangular, triangular, hexagonal, annular, etc., or any other shape. As used herein, the term "spot size" refers to the diameter or maximum spatial width of the delivered laser energy beam at the location where the beam axis 118 intersects the region of the workpiece 102 to be at least partially processed by the delivered laser energy beam (also referred to as the "process spot," "spot location," or simply "spot"). For purposes of discussion herein, spot size is measured as the distance from the beam axis 118 to the optical intensity on the beam axis 118 where the optical intensity drops to at least 1 / e of the optical intensity. 2 . Typically, the spot size of the laser energy beam will reach a minimum at the beam waist. Once delivered to the workpiece 102, the laser energy within the beam can be characterized as irradiating the workpiece 102 with a spot size ranging from 2 μm to 200 μm. However, it should be understood that the spot size can be less than 2 μm or greater than 200 μm. Thus, the laser energy beam delivered to the workpiece 102 can have a spot size greater than, less than, or equal to 2 μm, 3 μm, 5 μm, 7 μm, 10 μm, 15 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 80 μm, 100 μm, 150 μm, 200 μm, etc., or between any of these values.

[0026] Typically, the aforementioned 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 light spot and the workpiece 102. In view of the ensuing description, it should be appreciated that the inclusion of the first positioner 106 is optional (i.e., the apparatus 100 need not include the first positioner 106), provided that the apparatus 100 includes the second positioner 108, the third positioner 110, or a combination thereof. Similarly, it should be appreciated that the inclusion of the second positioner 108 is optional, provided that the apparatus 100 includes the first positioner 106, the third positioner 110, or a combination thereof. Furthermore, it should be similarly appreciated that the inclusion of the third positioner 110 is optional, provided that the apparatus 100 includes the first positioner 106, the second positioner 108, or a combination thereof. Finally, it should be appreciated that the apparatus 100 may include only the first positioner 106, only the second positioner 108, or only the third positioner 110, as appropriate.

[0027] The apparatus 100 also includes one or more optical components (e.g., a beam expander, a beam shaper, an aperture, a filter, a collimator, a lens, a mirror, a polarizer, a wave plate, a diffractive optical element, a refractive optical element, or the like, or any combination thereof) to focus, expand, collimate, shape, polarize, filter, split, combine, crop, or otherwise modify, condition, direct, etc., the beam of laser energy obtained from the laser source 104 along one or more beam paths (e.g., beam path 116) to the scan lens 112. Such optical components may be inserted into the beam path 116 at any suitable or desired location (e.g., between the laser source 104 and the first positioner 106, between the laser source 104 and the second positioner 108, between the first positioner 106 and the second positioner 108, between the second positioner 108 and the scan lens 112, etc., or any combination thereof).

[0028] One example of such an optical component is a variable optical attenuator (VOA), which is configured to selectively and variably reduce the power of laser pulses propagating along the beam path 116. Examples of VOAs that may be incorporated may include one or more systems such as a variable neutral density filter, an acousto-optical (AO) modulator (AOM), an AO deflector (AOD), a liquid crystal variable attenuator (LCVA), a micro-electro-mechanical system (MEMS)-based VOA, an optical attenuator wheel, a polarizer / wave plate filter, the like, or any combination thereof.

[0029] Another example of such an optical component is a beam size adjustment mechanism operable to selectively and variably adjust the size of the laser energy beam (also referred to herein as the "beam size") incident on the scan lens 112. As used herein, the term "beam size" refers to the diameter or width of the laser energy beam and can be measured as 1 / e of the optical intensity at the beam axis 118 where the optical intensity drops to the propagation axis along the beam path 116. 2 Examples of beam size adjustment mechanisms that may be incorporated include an AOD system, a zoom lens, a motorized variable beam expander, a deformable mirror, a variable radius mirror, a variable focus corrugated lens, a motorized Z-axis lens, a motorized iris stop, a motorized aperture wheel, and the like, or any combination thereof. Adjusting the beam size of the laser energy beam incident on the scan lens 112 may result in a change in the spot size at the workpiece 102.

[0030] Another example of such an optical component is a beam shape adjustment mechanism that is operable to selectively and variably adjust the shape of the laser energy beam (also referred to herein as the "beam size") incident on the scan lens 112. Examples of beam shape adjustment mechanisms that may be incorporated include an AOD, a deformable mirror, a variable radius mirror, a variable focus corrugated lens, and the like, or any combination thereof. Adjusting the beam shape of the laser energy beam incident on the scan lens 112 can result in a change in the spot shape at the workpiece 102.

[0031] A. Laser Source

[0032] In one embodiment, the laser source 104 is operable to generate laser pulses. Thus, the laser source 104 may comprise a pulsed laser source, a CW laser source, a QCW laser source, a burst-mode laser, or the like, or any combination thereof. Where the laser source 104 comprises a QCW or CW laser source, the laser source 104 may further comprise a pulse gating unit (e.g., an acousto-optic (AO) modulator (AOM), a beam chopper, etc.) to temporally modulate the laser radiation beam output from the QCW or CW laser source. Although not illustrated, the apparatus 100 may optionally include one or more harmonic generation crystals (also referred to as "wavelength conversion crystals") configured to convert the wavelength of light output by the laser source 104. However, in another embodiment, the laser source 104 may be provided as a QCW laser source or a CW laser source and may not include a pulse gating unit. Thus, the laser source 104 may be broadly characterized as being operable to generate a laser energy beam, which may manifest as a series of laser pulses or a continuous or quasi-continuous laser beam, which may then propagate along the beam path 116. Although many of the embodiments discussed herein refer to laser pulses, it will be appreciated that a continuous beam may alternatively or additionally be employed whenever appropriate.

[0033] Lasers in the UV range of the electromagnetic spectrum may have one or more wavelengths in the range of 10 nm (or so) to 385 nm (or so), such as 10 nm, 121 nm, 124 nm, 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, etc., or values ​​between any of these values. Lasers in the visible green range of the electromagnetic spectrum may have one or more wavelengths in the range of 500 nm (or so) to 560 nm (or so), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, etc., or values ​​between any of these values. Lasers in the IR range of the electromagnetic spectrum may have one or more wavelengths in the range of 750 nm (or thereabouts) to 15 μm (or thereabouts), such as 600 nm to 1000 nm, 752.5 nm, 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm, 1053 nm, 1060 nm, 1064 nm, 1080 nm, 1090 nm, 1152 nm, 1150 nm to 1350 nm, 1540 nm, 2.6 μm to 4 μm, 4.8 μm to 8.3 μm, 9.4 μm, 10.6 μm, etc., or a value between any of these values.

[0034] The laser pulses output by the laser source 104 may have a pulse width or pulse duration (i.e., based on the full-width at half-maximum (FWHM) of the pulse optical power versus time) in the range of 10 fs to 900 ms. However, it will be appreciated that the pulse duration may be less than 10 fs or greater than 900 ms. Thus, at least one laser pulse output by the laser source 104 may have a pulse duration less than, greater than, or equal to the following values: 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, ​​2 00ps, 500ps, 1ns, 1.5ns, 2ns, 5ns, 10ns, 20ns, 50ns, 100ns, 200ns, 400ns, 800ns, 1000ns, 2μs, 5μs, 10μs, 50μs, 100μs, 300μs, 500μs, 900μs, 1ms, 2ms, 5ms, 10ms, 20ms, 50ms, 100ms, 300ms, 500ms, 900ms, 1s, etc., or a value between any of these values.

[0035] The laser pulses output by the laser source 104 may have an average power in the range of 5 mW to 50 kW. However, it will be appreciated that the average power may be less than 5 mW or greater than 50 kW. Thus, the laser pulses output by the laser source 104 may have an average power less than, greater than, or equal to 5 mW, 10 mW, 15 mW, 20 mW, 25 mW, 50 mW, 75 mW, 100 mW, 300 mW, 500 mW, 800 mW, 1 W, 2 W, 3 W, 4 W, 5 W, 6 W, 7 W, 10 W, 15 W, 18 W, 25 W, 30 W, 50 W, 60 W, 100 W, 150 W, 200 W, 250 W, 500 W, 2 kW, 3 kW, 20 kW, 50 kW, etc., or values ​​between any of these values.

[0036] Laser pulses may be output by the laser source 104 at a pulse repetition rate in the range of 5 kHz to 1 GHz. However, it will be appreciated that the pulse repetition rate may be less than 5 kHz or greater than 1 GHz. Thus, laser pulses may be output by the laser source 104 at a pulse repetition rate less than, greater than, or equal to 5 kHz, 50 kHz, 100 kHz, 175 kHz, 225 kHz, 250 kHz, 275 kHz, 500 kHz, 800 kHz, 900 kHz, 1 MHz, 1.5 MHz, 1.8 MHz, 1.9 MHz, 2 MHz, 2.5 MHz, 3 MHz, 4 MHz, 5 MHz, 10 MHz, 20 MHz, 50 MHz, 60 MHz, 100 MHz, 150 MHz, 200 MHz, 250 MHz, 300 MHz, 350 MHz, 500 MHz, 550 MHz, 600 MHz, 900 MHz, 2 GHz, 10 GHz, etc., or values ​​between any of these values.

[0037] In addition to wavelength, pulse duration, average power, and pulse repetition rate, the laser pulses delivered to the workpiece 102 may also be characterized by one or more other characteristics such as pulse energy, peak power, etc., which may be selected (e.g., optionally based on one or more other characteristics such as wavelength, pulse duration, average power, and pulse repetition rate) to produce an optical intensity (in W / cm2) sufficient to process the workpiece 102 (e.g., to form one or more features having one or more desired characteristics). 2 Measurement), flux (in J / cm 2 measurement) and the like to irradiate the workpiece 102 at the process light spot.

[0038] Examples of laser types for the laser source 104 may be characterized as gas lasers (e.g., carbon dioxide lasers, carbon monoxide lasers, excimer lasers, etc.), solid-state lasers (e.g., Nd:YAG lasers, etc.), rod lasers, fiber lasers, photonic crystal rod / fiber lasers, passively mode-locked solid-state bulk or fiber lasers, dye lasers, mode-locked diode lasers, pulsed lasers (e.g., ms, ns, ps, fs pulsed lasers), CW lasers, QCW lasers, or the like, or any combination thereof. Depending on the configuration of these lasers, 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, pulsed mode, or any combination thereof). Specific examples of laser sources that may be provided as the laser source 104 include one or more laser sources such as: the BOREAS, HEGOA, SIROCCO, or CHINOOK series lasers manufactured by EOLITE; the PYROFLEX series lasers manufactured by PYROPHOTONICS; the PALADIN Advanced 355, DIAMOND series (e.g., DIAMOND E, G, J-2, J-3, J-5 series), FLARE NX, MATRIX QSDPSS, MEPHISTOQ, AVIA LX, AVIA NX, RAPID NX, HYPERRAPID NX, RAPID, HELIOS, FIDELITY, MONACO, OPERA, or RAPID FX series lasers manufactured by COHERENT; the ASCEND, ELEMENT 2, ELEMENT 3, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75 2CEP4, EXCELSIOR, EXPLORER, HIPPO, ICEFYRE, NAVIGATOR, QUANTA-RAY, QUASAR, SPIRIT, SPIRIT 1030-100, SPIRIT 1030-70, SPIRIT 515-50, TALON, or VGEN series lasers; PULSTAR or FIRESTAR series lasers manufactured by SYNRAD; TRUFLOW series lasers (e.g., TRUFLOW 2000, 1700, 3000, 3200, 3600, 4000, 5000, 6000, 6000, 8000, 10000, 12000, 15000, 20000), TRUCOAX series lasers (e.g., TRUCOAX 1000) or TRUDISK, TRUPULSE, TRUDIODE, TRUFIBER or TRUMICRO series lasers, all manufactured by TRUMPF; FCP APJEWEL or FEMTOLITE series lasers manufactured by IMRAAMERICA;TANGERINE and SATSUMA series lasers (and MIKAN and T pulse train oscillators) manufactured by AMPLITUDE SYSTEMES; CL, CLPF, CLPN, CLPNT, CLT, ELM, ELPF, ELPN, ELPP, ELR, ELS, FLPN, FLPNT, FLT, GLPF, GLPN, GLR, HLPN, HLPP, RFL, TLM, TLPN, TLR, ULPN, ULR, VLM, VLPN, YLM, YLPF, YLPN, YLPP, YLR, YLS, FLPM, FLPMT, DLM, BLM, or DLR series lasers manufactured by IPG PHOTONICS (including, for example, GPLN-100-M, GPLN-500-QCW, GPLN-500-M, GPLN-500-R, GPLN-2000-S, etc.), etc., or any combination thereof.

[0039] B. First locator

[0040] The first positioner 106 is configured, positioned, or otherwise disposed in the beam path 116 and operates to diffract, reflect, refract, or the like, or any combination thereof, the laser pulses generated by the laser source 104 (i.e., to "deflect"), thereby deflecting or imparting movement to the beam path 116 (e.g., relative to the scan lens 112) and, therefore, to impart movement to the beam axis 118 relative to the workpiece 102. Generally, the first positioner 106 is operable to impart movement to the beam axis 118 relative to the workpiece 102 (e.g., along the X-axis (or direction), the Y-axis (or direction), or a combination thereof, within a first scan range projected onto the workpiece 102 by the scan lens 112). Although not illustrated, the X-axis (or X-direction) should be understood to refer to an axis (or direction) orthogonal to the illustrated Y and Z-axes (or directions).

[0041] Typically, and 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 scan range can extend in either the X or Y direction by a distance less than, greater than, or equal to 0.01 mm, 0.04 mm, 0.1 mm, 0.5 mm, 1.0 mm, 1.4 mm, 1.5 mm, 1.8 mm, 2 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.2 mm, 5 mm, 10 mm, 25 mm, 50 mm, 60 mm, etc., or a value between any of these values. The maximum dimension of the first scan range (e.g., in the X or Y direction, or otherwise) can be greater than, equal to, or less than the maximum dimension (as measured in the XY plane) of a feature (e.g., an opening, recess, via, trench, etc.) to be formed in the workpiece 102.

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

[0043] The first positioner 106 can be provided as a micro-electro-mechanical-system (MEMS) mirror or mirror array, an AOD system, an electro-optical deflector (EOD) system, a fast-steering mirror (FSM) element (including a piezoelectric actuator, an electrostrictive actuator, a voice coil actuator, etc.), a galvanometer mirror system, a rotating polygon scanner, or the like or any combination thereof. In one embodiment, the first positioner 106 is provided as an AOD system comprising at least one (e.g., one, two, three, four, etc.) single-element AOD system, at least one (e.g., one, two, three, four, etc.) phased array AOD system, or the like or any combination thereof. The single-element and phased array AOD systems each include an AO unit 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 refers to an AOD system having only a single ultrasonic transducer element acoustically coupled to an AO unit cell, while a "phased array" AOD system includes a phased array of at least two ultrasonic transducer elements acoustically coupled to a common AO unit cell.

[0044] Those skilled in the art will recognize that AO technology (e.g., AOD, AOM, etc.) utilizes diffraction effects caused by acoustic waves propagating through an AO cell to modulate one or more properties of a light wave (in the context of this application, a laser energy beam) simultaneously propagating through the AO cell. Typically, an AO cell is capable of supporting both acoustic and light waves in the same region. The acoustic wave imparts a refractive index perturbation within the AO cell. The acoustic wave is typically launched into the AO cell by driving an ultrasonic transducer element at one or more RF frequencies. By controlling the properties of the acoustic wave (e.g., amplitude, frequency, phase, etc.), one or more properties of the propagating light wave can be controllably modulated to impart movement to the beam path 116 (e.g., relative to the scan lens 112). It will also be appreciated that the properties of the acoustic wave launched into the AO cell can be controlled using well-known techniques to cause the energy in the laser energy beam to attenuate as the beam passes through the AO cell. Thus, the AOD system can also be operated to modulate the pulse energy (and, accordingly, the flux, peak power, optical intensity, average power, etc.) of the laser pulse ultimately delivered to the workpiece 102.

[0045] By deflecting the beam path 116, any of the AOD systems can be provided as a single-axis AOD system (e.g., operable to impart movement of the beam axis 118 along a single direction) or a multi-axis AOD system (e.g., operable to impart movement of the beam axis 118 along one or more axes, such as along the X-axis, along the Y-axis, or any combination thereof). Typically, the multi-axis AOD system can be provided as a multi-cell system or a single-cell system. A multi-cell, multi-axis system typically includes multiple AOD systems, each of which is operable to impart movement of the beam axis 118 along a different axis. For example, a multi-cell, multi-axis system can include a first AOD system (e.g., a single element or phased array AOD system) that is operable to impart movement of the beam axis 118 along the X-axis (e.g., an "X-axis AOD system"), and a second AOD system (e.g., a single element or phased array AOD system) that is operable to impart movement of the beam axis 118 along the Y-axis (e.g., a "Y-axis AOD system"). A single-cell multi-axis system (e.g., an "X / Y-axis AOD system") typically includes a single AOD system operable to impart movement of the beam axis 118 along the X and Y axes. For example, a single-cell system may include at least two ultrasonic transducer elements acoustically coupled to orthogonally arranged planes, facets, sides, etc., of a common AO cell.

[0046] C. Second locator

[0047] The second positioner 108 is disposed in the beam path 116 and is operable to diffract, reflect, refract, or the like, or any combination thereof (i.e., to "deflect") the laser pulses generated by the laser source 104 and passed through the first positioner 106, thereby deflecting or imparting movement to the beam path 116 (e.g., relative to the scan lens 112) and, therefore, to deflect or impart movement to the beam axis 118 relative to the workpiece 102. Typically, the second positioner 108 is operable to impart movement to the beam axis 118 relative to the workpiece 102 (e.g., along the X-axis (or direction), the Y-axis (or direction), or a combination thereof, within a second scan range projected onto the workpiece 102 by the scan lens 112).

[0048] Typically, and 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 scan range can extend to a distance in either the X or Y direction that is greater than the corresponding distance of the first scan range. In view of the above, the second scan range can extend to a distance in either the X or Y direction that is less than, greater than, or equal to the following: 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 a value between any of these values. The maximum dimension of the second scan range (e.g., in the X or Y or other directions) can be greater than, equal to, or less than the maximum dimension (as measured in the XY plane) of a feature (e.g., an opening, a recess, a via, a trench, a scribe line, a conductive trace, etc.) to be formed in the workpiece 102.

[0049] In view of the configurations described herein, it will be appreciated that the movement of the beam axis 118 imparted by the first positioner 106 may overlap with the movement of the beam axis 118 imparted by the second positioner 108. Thus, the second positioner 108 is operable to scan the first scanning range within the second scanning range.

[0050] Typically, the second positioner 108 is capable of positioning the process spot at any location 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) at a positioning rate that spans a range less 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 of 500 Hz (or thereabouts) to 8 kHz (or thereabouts). For example, the second positioning bandwidth can be greater than, equal to, or less than 500 Hz, 750 Hz, 1 kHz, 1.25 kHz, 1.5 kHz, 1.75 kHz, 2 kHz, 2.5 kHz, 3 kHz, 3.5 kHz, 4 kHz, 4.5 kHz, 5 kHz, 5.5 kHz, 6 kHz, 6.5 kHz, 7 kHz, 7.5 kHz, 8 kHz, etc., or a value between any of these values.

[0051] In view of the above, it should be understood that the second positioner 108 can be provided as a microelectromechanical system (MEMS) mirror or mirror array, an AOD system, an electro-optical deflector (EOD) system, a fast steering mirror (FSM) element (incorporating 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 the like or any combination thereof. In one embodiment, the second positioner 108 can be provided as a galvanometer mirror system including two galvanometer mirror assemblies, namely, a first galvanometer mirror assembly configured to impart movement of the beam axis 118 relative to the workpiece 102 along the X-axis (e.g., an X-axis galvanometer mirror assembly), and a second galvanometer mirror assembly configured to impart movement of the beam axis 118 relative to the workpiece 102 along the Y-axis (e.g., a Y-axis galvanometer mirror assembly). However, in another embodiment, the second positioner 108 can be provided as a galvanometer mirror system including a single galvanometer mirror element configured to impart X- and Y-axis motion to the beam axis 118 relative to the workpiece 102. In still other embodiments, the second positioner 108 can be provided as a rotating polygon mirror system, etc. It should be understood that, depending on the specific configuration of the second positioner 108 and the first positioner 106, the second positioning bandwidth can be greater than or equal to the first positioning bandwidth.

[0052] D. Third locator

[0053] The third positioner 110 is operable to impart movement to the workpiece 102 relative to the scan lens 112, and therefore relative to the beam axis 118. Movement of the workpiece 102 relative to the beam axis 118 is generally limited, allowing the process spot to be scanned, moved, or otherwise positioned within a third scan field, or "third scan range." Depending on one or more factors, such as the configuration of the third positioner 110, the third scan range may extend in either the X or Y direction to a distance greater than or equal to the corresponding distance of the second scan range. However, typically, the maximum dimension of the third scan range (e.g., in the X or Y direction, or other directions) will be greater than or equal to the corresponding maximum dimension of any feature to be formed in the workpiece 102 (as measured in the XY plane). Optionally, the third positioner 110 is operable to move the workpiece 102 relative to the beam axis 118 within a scan range that extends in the Z direction (e.g., within a range between 1 mm and 50 mm). Thus, the third scan range may extend along the X, Y, and / or Z directions.

[0054] In view of the configurations described herein, it should be appreciated that the movement of the process spot relative to the workpiece 102 (e.g., as imparted by the first positioner 106 and / or the second positioner 108) can overlap with the movement of the workpiece 102 as imparted by the third positioner 110. Thus, the third positioner 110 can be operated to scan the first scanning range and / or the second scanning range within a third scanning range. Typically, the third positioner 110 is capable of positioning the workpiece 102 at any position within the third scanning range (and thus causing the workpiece 102 to move, scan the first scanning range within the third scanning range, and / or scan the second scanning range within the third scanning range) at a positioning rate that spans a range that is less than the second positioning bandwidth (also referred to herein as the "third positioning bandwidth"). In one embodiment, the third positioning bandwidth is less than 500 Hz (or thereabouts). For example, the third positioning bandwidth may be equal to or less than 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 between any of these values.

[0055] In one embodiment, the third positioner 110 is provided as one or more linear stages (e.g., each capable of imparting translational movement to the workpiece 102 in the X, Y, and / or Z directions), one or more rotational stages (e.g., each capable of imparting rotational movement to the workpiece 102 about an axis parallel to the X, Y, and / or Z directions), or the like, or any combination thereof. In one embodiment, the third positioner 110 includes an X-stage for translating the workpiece 102 in the X direction, and a Y-stage supported by the X-stage (and therefore movable in the X direction by the X-stage) for translating the workpiece 102 in the Y direction.

[0056] Although not shown, the apparatus 100 may optionally include a fixture (e.g., a chuck) coupled to the platform of the third locator 110. The fixture may include a support area, and the workpiece 102 may be mechanically clamped, fixed, held, fastened to the fixture, or otherwise supported by the fixture within the support area. In one embodiment, the workpiece 102 may be clamped, fixed, held, fastened, or otherwise supported so as to directly contact the primary, typically flat, support surface of the fixture. In another embodiment, the workpiece 102 may be clamped, fixed, held, fastened, or otherwise supported so as to be spaced apart from the support surface of the fixture. In one embodiment, the workpiece 102 may be fixed, held, or fastened by means of a force (e.g., electrostatic force, vacuum force, magnetic force) selectively applied to the workpiece 102 from the fixture or otherwise present between the workpiece 102 and the fixture.

[0057] As described so far, the apparatus 100 utilizes a so-called “stacked” positioning system as the third positioner 110, which enables the workpiece 102 to move while the positions of other components, such as the first positioner 106, the second positioner 108, the scan lens 112, etc., remain stationary relative to the workpiece 102 within the apparatus 100 (e.g., via one or more supports, frames, etc., as known in the art). In another embodiment, the third positioner 110 can be configured and operable to move one or more components, such as the first positioner 106, the second positioner 108, the scan lens 112, etc., while the workpiece 102 can remain stationary.

[0058] In yet another embodiment, 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 the like, or any combination thereof, are carried by one or more linear or rotary stages (e.g., mounted on a frame, gantry, etc.) and the workpiece 102 is carried by one or more other linear or rotary stages. In such an embodiment, the third positioner 110 includes one or more linear or rotary stages configured 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 rotary stages configured and operable to move the workpiece 102. For example, the third positioner 110 may include a Y-stage for imparting movement to the workpiece 102 in the Y direction and an X-stage for imparting movement to the scan head in the X direction. Some examples of separation platform positioning systems that may be beneficially or advantageously used in apparatus 100 include any of the separation platform positioning systems disclosed in U.S. Patent Nos. 5,751,585, 5,798,927, 5,847,960, 6,606,999, 7,605,343, 8,680,430, 8,847,113, or U.S. Patent Application Publication No. 2014 / 0083983, or any combination thereof.

[0059] In one embodiment, the third positioner 110 includes a Z-stage, and the Z-stage can be configured to move the workpiece 102 in the Z direction. In this case, the Z-stage can be carried by one or more of the other aforementioned stages for moving or positioning the workpiece 102, can carry one or more of the other aforementioned stages for moving or positioning the workpiece 102, or any combination thereof. In another embodiment, the third positioner 110 includes a Z-stage, and the Z-stage can be configured to move the scan lens 112 in the Z direction. Thus, in the case where the third positioner 110 is provided as a separate-stage positioning system, the Z-stage can carry or be carried by the X-stage. Moving the workpiece 102 or the scan lens 112 in the Z direction can cause the spot size at the workpiece 102 to change.

[0060] In yet another embodiment, one or more components, such as the first positioner 106, the second positioner 108, and the scan lens 112, may be carried by an articulated multi-axis robotic arm (e.g., a 2-axis, 3-axis, 4-axis, 5-axis, or 6-axis arm). In this embodiment, the second positioner 108 and / or the scan lens 112 may be carried by the end effector of the robotic arm, as appropriate. In yet another embodiment, the workpiece 102 may be carried directly on the end effector of the articulated multi-axis robotic arm (i.e., without the third positioner 110). In yet another embodiment, the third positioner 110 may be carried by the end effector of the articulated multi-axis robotic arm.

[0061] D. Scan lens

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

[0063] In one embodiment, the scan lens 112 and the second positioner 108 are integrated into a common housing or "scan head." Thus, in one embodiment where the apparatus 100 includes a lens actuator, the lens actuator can be coupled to the scan lens 112 (e.g., to enable movement of the scan lens 112 within the scan head relative to the second positioner 108). Alternatively, the lens actuator can be coupled to the scan head (e.g., to enable movement of the scan head itself, in which case the scan lens 112 and the second positioner 108 will move together). In another embodiment, the scan lens 112 and the second positioner 108 are integrated into different housings (e.g., so that the housing into which the scan lens 112 is integrated can move relative to the housing into which the second positioner 108 is integrated). Components of the scan head, or the entire scan head itself, can be modular assemblies so that components of the scan head can be easily removed and replaced with another component, so that one scan head can be easily removed and replaced with another scan head, and so on.

[0064] E. Field of view

[0065] The apparatus 100 may further include one or more cameras, such as camera 113 (e.g., a CCD camera, a CMOS camera, etc., or any combination thereof), having a field of view encompassing the area occupied by the workpiece 102 provided to the apparatus 100 for processing. The camera 113 may be coupled to the scan lens 112 or the aforementioned scan head. In another embodiment, if the third positioner 110 is provided as a separate platform positioning system, the camera 113 may be coupled to any platform configured and operable to move the scan lens 112 or the scan head (rather than the scan lens 112 or the scan head itself). In yet another embodiment, the apparatus 100 may include a structure such as a frame, a stage, or the like (generally referred to herein as an "inspection support"), and the camera 113 may be coupled to the inspection support. In this embodiment, the apparatus 100 may include one or more linear or rotary stages to move the inspection support (e.g., relative to the workpiece 102), move the camera 113 (e.g., relative to the inspection support), or similar processes, or any combination thereof. The camera 113 may generate image data representing images captured within its field of view and output the image data (eg, as one or more image signals) to the controller 114 .

[0066] The image data may be interpreted, manipulated, input into an algorithm, or otherwise processed in any desired or other suitable manner known in the art (e.g., at controller 114, remote system 126, or the like, or any combination thereof) to facilitate one or more operations, such as alignment of workpiece 102 within apparatus 100, calibration (e.g., of features formed as a result of machining workpiece 102), visual inspection, or the like, or any combination thereof. To the extent that the image data is used to facilitate an inspection process (e.g., a visual inspection process), any camera (e.g., camera 113) that generates the image data may be considered part of an "inspection system." Thus, an inspection system may include a single camera or multiple cameras.

[0067] although Figure 1 The apparatus 100 is described as including only one camera 113, but it should be understood that multiple cameras 113 (e.g., differing in resolution, field of view, or the like, or any combination thereof) may be used. 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, while the second camera may have a relatively small field of view and a relatively high resolution. Typically, the field of view of the second camera will be within the field of view of the first camera. However, the first and second cameras may be configured such that the field of view of the second camera is positioned outside the field of view of the first camera. Additionally, the camera 113 may have a field of view projected onto the workpiece 102 that is larger than the first scanning range or the second scanning range.

[0068] Additionally, and although not illustrated, apparatus 100 may include an illumination system (eg, any suitable machine vision illumination system known in the art) operable to illuminate the field of view of a camera (eg, camera 113).

[0069] In the illustrated embodiment, camera 113 is laterally offset from scan lens 112. Thus, the field of view of camera 113 (i.e., as projected onto workpiece 102) may be at least partially outside the scan field projected onto workpiece 102 by scan lens 112. In another embodiment, apparatus 100 may include one or more optical components (e.g., one or more beam splitters, mirrors, lenses, or the like, or any combination thereof) in any manner known in the art that enable the field of view of a camera (e.g., camera 113) to be projected through scan lens 112.

[0070] F. Controller

[0071] Typically, the apparatus 100 includes one or more controllers, such as the controller 114, to control or facilitate control of the operation of the apparatus 100. In one embodiment, the controller 114 is communicatively coupled to one or more components of the apparatus 100, such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (when provided as a variable focus lens), the fixture, the camera 113, the VOA, the beam size adjustment mechanism, etc. (e.g., via one or more wired or wireless, serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, or the like, or any combination thereof), so that the one or more components can operate in response to one or more control signals output by the controller 114.

[0072] For example, the controller 114 can control the operation of the first positioner 106, the second positioner 108, or the third positioner 110 to impart relative movement between the beam axis and the workpiece 102 to cause relative movement between the process spot and the workpiece 102 along a path or trajectory (also referred to herein as a "process trajectory") within the workpiece 102. In another example, and as will be described in more detail below, the controller 114 can control the operation of the third positioner 110 to impart relative movement between the camera 113 and the workpiece 102 after the workpiece 102 has been processed to enable detection of features formed in the workpiece 102 as a result of the processing.

[0073] Typically, the controller 114 includes one or more processors operable to generate the aforementioned control signals after executing instructions. The processor may be provided as a programmable processor operable to execute instructions (e.g., including one or more general-purpose computer processors, microprocessors, digital signal processors, or the like, or any combination thereof). The instructions executable by the processor may be implemented as software, firmware, or any suitable form of circuitry, including a programmable logic device (PLD), a field-programmable gate array (FPGA), a field-programmable object array (FPOA), an application-specific integrated circuit (ASIC) - including digital, analog, and mixed analog / digital circuitry, or the like, or any combination thereof. The execution of instructions may be performed on a single processor, distributed among multiple processors, performed in parallel across processors within a device or across a network of devices, or the like, or any combination thereof.

[0074] In one embodiment, the controller 114 includes tangible media such as computer memory that can be accessed by the processor (e.g., via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (e.g., tape, hard drive, etc.), optical disks, volatile or non-volatile semiconductor memory (e.g., RAM, ROM, NAND flash memory, NOR flash memory, SONOS memory, etc.), etc., and can be accessed locally, remotely (e.g., across a network), or a combination thereof. Typically, the instructions can be stored as computer software (e.g., executable code, files, instructions, etc., library files, etc.) that can be easily authorized by a skilled person based on the description provided herein, and are written in, for example, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, assembly language, hardware description language (e.g., VHDL, VERILOG, etc.). Computer software is typically stored in one or more data structures transported by computer memory.

[0075] Although not shown, one or more drivers (e.g., RF drivers, servo drivers, line drivers, power supplies, etc.) can be communicatively coupled to inputs of one or more components, such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (when provided as a variable focus lens), the fixture, the camera 113, the VOA, a beam size adjustment mechanism, etc. In one embodiment, each driver typically includes an input to which the controller 114 is communicatively coupled, and the controller 114 is thereby operative to generate one or more control signals (e.g., trigger signals, etc.), which can be transmitted to inputs of the one or more drivers associated with the one or more components of the apparatus 100. Thus, components such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (when provided as a variable focus lens), the fixture, the camera 113, the VOA, the beam size adjustment mechanism, etc. respond to control signals generated by the controller 114.

[0076] In another embodiment, and although not shown, one or more additional controllers (e.g., component-specific controllers) may optionally be communicatively coupled to inputs of a driver communicatively coupled to (and therefore associated with) a component, such as the laser source 104, the first positioner 106, the second positioner 108, the third positioner 110, the lens actuator, the scan lens 112 (when provided as a variable focus lens), the fixture, the camera 113, the VOA, a beam size adjustment mechanism, etc. In this embodiment, each component-specific controller may be communicatively coupled, and the controller 114 may be operable to generate one or more control signals (e.g., a trigger signal, etc.) in response to one or more control signals received from the controller 114, which may then be transmitted to the inputs of the driver to which the controller is communicatively coupled. In this embodiment, the component-specific controllers may operate in a manner similar to that described with respect to the controller 114.

[0077] In another embodiment where one or more component-specific controllers are provided, a component-specific controller associated with one component (e.g., laser source 104) can be communicatively coupled to a component-specific controller associated with one component (e.g., first positioner 106, etc.). In this embodiment, one or more of the component-specific controllers can be operable to generate one or more control signals (e.g., trigger signals, etc.) in response to one or more control signals received from one or more other component-specific controllers.

[0078] G. User Interface

[0079] The device 100 may further include a user interface 120 that is communicatively coupled to the controller 114 (e.g., via one or more wired or wireless, serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, or the like, or any combination thereof). The user interface 120 may include one or more output devices, one or more input devices, or any combination thereof. Generally, an output device is any device capable of presenting or otherwise communicating information through any human perceptible stimulus (e.g., visual, auditory, tactile, etc.). Examples of output devices include monitors, printers, speakers, tactile actuators, and the like. Generally, an input device is any device that enables, for example, a user of the device 100 to provide instructions, commands, parameters, information, or the like to operate the device 100 (or to facilitate the operation of the device 100). Examples of input devices include a keyboard, mouse, touchpad, touchscreen, microphone, camera, and the like.

[0080] H. Communication module

[0081] Optionally, the device 100 includes a communication module 122 that is communicatively coupled to the controller 114 (e.g., via one or more wired or wireless, serial, or parallel communication links, such as USB, RS-232, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, or the like, or any combination thereof). The communication module 122 is operable to transmit data, receive data, or a combination thereof. Thus, the communication module 122 may include circuitry, an antenna, a connector, or the like, or any combination thereof, to transmit data to another device or network (e.g., network 124) and / or receive data via a wired or wireless link. In one example, the communication module 122 may be a connector that operates in conjunction with software or firmware in the controller 114 to function as a serial port (e.g., RS-232), a Universal Serial Bus (USB) port, an IR interface, or the like, or any combination thereof. In another example, the communication module 122 can be a universal interface driver application-specific integrated circuit (UIDA) that supports a plurality of different host interface protocols, such as RS-232C, IBM 46XX, keyboard slot interface, or the like, or any combination thereof. The communication module 122 can include one or more modules, circuits, antennas, connectors, or the like known in the art to support other known communication modes, such as USB, Ethernet, Bluetooth, Wi-Fi, infrared (e.g., IrDa), RFID communication, or the like, or any combination thereof. Instead of being a separate component from the controller 114, it should be understood that the communication module 122 can be incorporated as part of the controller 114 in any known or suitable manner.

[0082] The network 124 may be communicatively coupled to one or more systems remote from the device 100 (e.g., remote system 126, as in FIG. 1 ) (e.g., via one or more wired or wireless, serial or parallel communication links, such as USB, RS-232, Ethernet, Firewire, WiFi, RFID, NFC, Bluetooth, Li-Fi, SERCOS, MARCO, EtherCAT, or the like, or any combination thereof). Figure 1100 ). In one embodiment, remote system 126 may be a device such as a computer (e.g., a desktop computer, laptop computer, tablet computer, smartphone, etc.), a computing system (e.g., a cloud computing platform), another controller or communication module (e.g., associated with another device such as device 100), or the like, or any combination thereof. It should be understood that remote system 126 may include or otherwise be coupled to a user interface, including one or more output devices, one or more input devices, or any combination thereof, as exemplarily described above with respect to user interface 120. Remote system 126 may be a device owned or otherwise operated by a user of device 100, by the manufacturer of device 100, by a technician responsible for performing maintenance on device 100, or the like, or any combination thereof.

[0083] Via the communication module 122 and the network 124, the controller 114 can communicate various data to the remote system 126. Examples of data that can be output to the remote system 126 include the aforementioned image data or measurement data (discussed in more detail below), or the like, or any combination thereof. The data output by the remote system 126 can be input to the controller 114 (e.g., via the network 124 and the communication module 122) and represent instructions, commands, parameters, information, or the like to operate the device 100 or otherwise affect or facilitate any operation of the device 100.

[0084] I. Beam Characterization Tools

[0085] Optionally, the apparatus 100 includes one or more beam characterization tools, such as the beam characterization tool 128, operable to measure one or more characteristics of the laser energy beam. Examples of characteristics that can be measured at the beam characterization tool 128 include the spatial energy distribution of a spot illuminated at the beam characterization tool 128 by the incident laser energy beam, phase, polarization, power, or the like, or any combination thereof. Thus, the beam characterization 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., a CCD, a CMOS, etc.), a wavefront sensor (e.g., a Shack-Hartmann wavefront sensor, etc.), or any other laser beam profiler known in the art, or the like, or any combination thereof. The beam characterization tool 128 can generate measurement data representative of one or more of the measured beam characteristics and output the measurement data (e.g., as one or more measurement signals) to the controller 114. Optionally, the measurement data (or data derived from the measurement data, such as by the controller 114 ) may be transmitted from the controller 114 to the remote system 126 (eg, via the communication module 122 and the network 124 ).

[0086] like Figure 1As schematically shown in FIG, the beam characterization tool 128 can be configured and arranged to measure one or more characteristics of the laser energy beam (each also generally referred to herein as a "beam characteristic") in any manner known in the art. For example, the beam characterization tool 128 is configured to measure one or more characteristics of the laser energy beam (e.g., as indicated by arrow 128a) at or near the location where the laser energy beam will process the workpiece 102 (also referred to herein as the "processing zone"), from a location along the beam path 116 (i.e., a sampling location), or any combination thereof. In one embodiment, the sampling location can be between the second positioner 108 and the scan lens 112 (e.g., as indicated by arrow 128b), between the first positioner 106 and the second positioner 108, between the laser source 104 and the first positioner 106, or the like.

[0087] In another embodiment, camera 113 (e.g., a first camera, a second camera, or the like, or any combination thereof) can be operated to capture an image of a light spot at workpiece 102, a fixture, an area outside of a fixture, or the like, or any combination thereof. Subsequently, in one implementation, the captured image can be processed at camera 113 such that the image data generated by camera 113 represents the spatial energy distribution of the light spot. In this case, the image data output by camera 113 can be considered "measurement data," and camera 113 can be considered an embodiment of beam characterization tool 128.

[0088] J.Laser sensor system

[0089] In one embodiment, the apparatus 100 includes a laser sensor system configured to measure laser energy or power. For example, the laser sensor system can be attached to the chuck and configured to measure the laser energy or power in the laser energy beam delivered from the scan lens 112. In another example, the apparatus 100 can include one or more optical components, such as a beam splitter disposed in the beam path 116 and configured to divert a portion of the laser energy propagating along the 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 in the diverted portion of the laser energy. Measurement data generated by the laser sensor system (e.g., in response to measuring laser energy or power) is output to the controller 114 (and optionally to the remote system 126), where the 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 transmission changes relative to RF power and frequency in the AOD system of the first positioner 106), or the like, or any combination thereof. Examples of operations that can be performed using measurement data from the laser sensor system are discussed in the aforementioned U.S. Patent No. 7,244,906, or the aforementioned U.S. Patent Application Publication Nos. 2014 / 0196140, 2014 / 0263201, or 2014 / 0263223, or International Patent Publication No. WO 2019 / 236616, or the like, or any combination thereof.

[0090] III. Discussion on Data and Information in General

[0091] The measurement data that has been generated (e.g., as discussed above) may be processed (e.g., in an automated manner at the controller 114, at the remote system 126, or at the like, or any combination thereof) to estimate, derive, identify, or otherwise obtain one or more spatial characteristics of the laser energy beam, one or more energy characteristics of the laser energy beam, or the like, or any combination thereof.

[0092] Examples of measurable spatial characteristics may include spatial energy distribution, spatial phase distribution, spatial polarization distribution, spot size, spot size, spot shape, spot shape, spot orientation, spot centroid, spot quality (e.g., as represented by an M2 parameter, as known in the art), or the like or any combination thereof. Spot shape may be measured, calculated, estimated, or otherwise determined using any known or suitable technique (e.g., such as any known technique for calculating circularity, roundness, etc.). For example, circularity may be determined according to the following formula:

[0093]

[0094] Where C is the circularity of the spot illuminated by the laser energy beam, A is the area of ​​the spot, and P is the perimeter of the area of ​​the spot.

[0095] Examples of energy characteristics may include spot flux, pulse energy (i.e., when the laser energy beam includes one or more laser energy pulses), average power, peak power, or the like, or any combination thereof. In some embodiments, data representing one or more of the aforementioned characteristics, such as pulse energy (i.e., when the laser energy beam includes one or more laser energy pulses), average power, peak power, or the like, or any combination thereof, may be used to facilitate determining an energy characteristic such as spot flux. 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 also be used to facilitate determining one or more energy characteristics. If not generated as measurement data, such data may be input to the controller 114 (e.g., via the user interface 120, the communication module 122, etc.) or otherwise accessible by the controller 114, the remote system 126, or the like, or any combination thereof.

[0096] The metrology data may be generated periodically, continuously (e.g., over a period of time, such as while the workpiece 102 is being processed), or before or after an event occurs, or any combination thereof. Examples of events that may trigger the generation of metrology data include initiating processing of the workpiece 102, completing processing of one or more workpieces 102, operating the apparatus 100 for a predetermined amount of time, operating the laser source 104 for a predetermined amount of time, or the like, or any combination thereof. Another example of an event that may trigger the generation of metrology data may include receiving an instruction to measure one or more beam characteristics (e.g., input via the user interface 120, the remote system 126, or the like, or any combination thereof).

[0097] Once estimated, derived, identified, or otherwise obtained from the measurement data, data representing one or more spatial or energy characteristics (generally referred to herein as "light point data") can be interpreted, manipulated, input into an algorithm, or otherwise processed (e.g., in an automated manner at the controller 114, the remote system 126, or the like, or any combination thereof) to support one or more operations.

[0098] Measurement data, spot data, or any other data (e.g., data representing pulse duration or pulse repetition frequency, data generated or otherwise obtained when performing a test or inspection operation after the workpiece 102 has been processed, data representing one or more other characteristics of the apparatus 100 such as: chip nozzle vacuum or air pressure and flow, vacuum pressure at the fixture, position sensor feedback associated with the second positioner 108 and / or the third positioner 110, temperature and / or humidity within a process carrier (typically, the process carrier is the space in which the workpiece 102 is disposed during processing), or the like or any combination thereof. Other data representing temperature and / or humidity within the ambient environment surrounding the apparatus 100, or the like or any combination thereof, may also be stored. It should be understood that data representing temperature and / or humidity within the process carrier, temperature and / or humidity within the ambient environment, etc., may be generated by one or more known types of temperature sensors, humidity sensors, or the like. In Figure 1 Such sensors are generally illustrated at 130 in FIG. Other data that may be stored includes data representing feedback signals associated with one or more positioners (e.g., the second positioner 108, the third positioner 110, or the like, or any combination thereof). Still other data may be derived from the measurement data, the spot data, or any of the foregoing (e.g., by processing such data at the controller 114, at the remote system 126, or the like, or any combination thereof) and may also be stored. Examples of such derived data include the total amount of laser energy delivered during feature formation, the pulse-averaged amount of laser energy delivered during feature formation (i.e., the total amount of laser energy delivered during feature formation divided by the number of pulses delivered during feature formation), the n-pulse moving average amount of laser energy (i.e., the moving average of the amount of laser energy delivered during feature formation divided by the number of pulses "n," where "n" may be set by a user or otherwise predetermined), and the like. Other examples of derived data that indicate the presence of a positioning error (e.g., as imparted by a positioner such as the second positioner 108), the magnitude of the positioning error, or the like, or any combination thereof, may be derived from feedback signals associated with the positioner. All such stored data may generally be referred to as "process control data."

[0099] The process control data may also include data representing one or more measured characteristics of the workpiece 102 (e.g., before being processed, during processing, or after processing, or any combination thereof). Examples of such data may include data representing measured characteristics such as the thickness of one or more constituent structures of the workpiece 102 or the entire workpiece, the surface quality of the workpiece 102 (e.g., characterization of any surface imperfections such as scratches, pits, etc.), the reflectivity of the workpiece 102, the temperature of the workpiece 102, the distance between the scanning lens 112 (or scanning head) and the workpiece 102, or the like or any combination thereof. These characteristics may be measured before a feature is formed at a region in the workpiece 102, when a feature is formed at the region, or after a feature has been formed at the region, or any combination thereof. Examples of sensors known in the art that can be used to generate such process control data include cameras (e.g., using various illumination methods), laser displacement sensors, confocal laser sensors, interferometers, inductive coating thickness gauges, stylus profilometers, touch probes, or the like or any combination thereof. In Figure 1 Such sensors are also generally illustrated at 130 in FIG.

[0100] Typically, testing or inspection operations may be performed by an automated optical inspection (AOI) system, an automated X-ray inspection (AXI) system, an in-circuit test (ICT) system, a wafer probe system, etc. In one embodiment, visual inspection of the workpiece 102 may be performed by one or more cameras incorporated into the apparatus 100 (i.e., the aforementioned "inspection system").

[0101] The process control data may be stored in association with the auxiliary information. Typically, storing the process control data (in association with the auxiliary information) is accomplished using one or more databases, which may reside locally (e.g., on a computer memory of the controller 114 or otherwise accessible by the controller) or remotely from the apparatus 100 (e.g., on a computer memory of the remote system 126 or otherwise accessible by the remote system), or the like, or any combination thereof.

[0102] Examples of auxiliary information that may be associated with process control data include information representing: an identification of the apparatus 100 (e.g., in terms of a serial number, model number, etc.), an identification of the workpiece 102 to be (or to have been) processed by the apparatus 100 (e.g., in terms of a lot number, serial number, model number, etc.), an identification (or location) of each feature to be (or to have been) formed in the workpiece 102, a date and / or time at which the process control was generated or otherwise obtained, or the like or any combination thereof. For example, process control data (e.g., data indicating laser energy, peak power, average power, pulse repetition rate, spot size, or the like, or any combination thereof) derived from metrology data generated when forming a first feature during machining of workpiece 102 may be associated with auxiliary information uniquely identifying the first feature (or the location of the first feature in workpiece 102), process control data (e.g., data indicating laser energy, peak power, average power, pulse repetition rate, spot size, or the like, or any combination thereof) derived from metrology data generated when forming a second feature during machining of workpiece 102 may be associated with auxiliary information uniquely identifying the second feature (or the location of the second feature in workpiece 102), etc. The location of the feature to be formed in workpiece 102 may be identified based on information provided by a user or generated by apparatus 100 (e.g., a CAD file or other tool path file describing a process trajectory, or the like, or any combination thereof) and any scaling parameters that may be calculated from alignment points captured by one or more cameras (e.g., camera 113).

[0103] The auxiliary information may also include "workpiece information," which describes one or more characteristics of the workpiece 102 as they exist before, during, or after processing, or any combination thereof. Examples of workpiece information may include the material construction of one or more constituent structures of the entire workpiece 102, a batch number, a panel number, a thickness map, or the like, or any combination thereof. The auxiliary information may also include "application information," which describes the manner in which the workpiece 102 will be (or has been) processed, and may describe the type of features to be formed in the workpiece 102, the location of the features to be formed in the workpiece 102, or the like, or any combination thereof. The workpiece information and application information may be provided by any suitable method (e.g., by a user interacting with the user interface 120, the remote system 126, or the like, or any combination thereof). In some embodiments, the workpiece information or application information may be encoded by a machine-readable indicia (e.g., one or more markings that can be captured and identified by a component of the apparatus 100, such as the camera 113). In other embodiments, the machine-readable indicia may encode a link (eg, a URL to a network resource containing artifact information or application information) that can be retrieved and recognized by a component of device 100 , such as camera 113 .

[0104] Once stored, the process control data may later be interpreted, manipulated, input into an algorithm, or otherwise processed (e.g., at the controller 114, at the remote system 126, or the like, or any combination thereof) to support one or more operations. Example embodiments of such operations are described in more detail below in the section entitled "Guided Detection."

[0105] A. Guided detection

[0106] After the workpiece 102 has been machined to form a plurality of features therein (e.g., blind holes, through holes, or a combination thereof), any of the aforementioned process control data may be processed (e.g., in conjunction with any auxiliary information stored in association with the process control data) to identify features that should be inspected because such features have a relatively high probability of being defective. Typically, this processing (referred to herein as a "candidate feature selection" process) may be performed at the controller 114, at the remote system 126, or the like or any combination thereof. Features that have been identified for inspection are referred to herein as "candidate features."

[0107] After the candidate features have been identified, third positioner 110 may be operated to move each candidate feature into the field of view of camera 113, and camera 113 may be operated to capture an image of each candidate feature within its field of view. The process of operating third positioner 110 and camera 113 to capture images of candidate features is referred to herein as "inspection." It will be appreciated that inspecting only the candidate features formed in workpiece 102 requires significantly less time than inspecting every feature formed in workpiece 102. It will also be appreciated that inspecting only the candidate features, rather than randomly sampling features formed in the workpiece, reduces the likelihood of missing areas of workpiece 102 containing defective features during inspection.

[0108] i. Additional Discussion on Candidate Feature Selection

[0109] As mentioned above, a candidate feature selection process is applied to process control data and any associated auxiliary information to identify candidate features for detection. In some embodiments, the candidate feature selection process applies one or more analytical methods and statistical thresholds (e.g., which may be determined empirically or identified as a result of computer modeling or simulation), one or more machine learning algorithms, or the like, or any combination thereof, to any of the process control data to estimate or determine which of the processed features are relatively likely to be defective. It should be understood that one or more suitable analytical methods and machine learning algorithms known in the art may be implemented to facilitate the candidate feature selection process.

[0110] A priori, an experienced process engineer can develop analysis methods and set appropriate thresholds for this candidate feature selection process. However, by coupling such process control data, the candidate feature selection process, one or more inspection systems, one or more cameras (e.g., camera 113), or the like, or any combination thereof, a learning feedback loop can be created, either by experienced humans using machine learning algorithms or automatically using manual, offline statistical correlations.

[0111] The candidate feature selection process may generate as output a data structure (e.g., a list) containing any process control data or auxiliary information for each feature (including the identification or location of each feature within the workpiece 102 or along the machining trajectory) that is estimated or determined to be relatively likely to be a defect. It should be understood that the estimated or determined likelihood output for any feature may be stored in association with the feature as auxiliary information, which may be used for later analysis, traceability purposes, the like, or any combination thereof.

[0112] Optionally, certain aspects of the candidate feature selection process can be tuned based on input from a user (e.g., provided via user interface 120, remote system 126, or the like, or any combination thereof). For example, a user can specify how many features should be included in the output data structure (e.g., in absolute or relative terms). In another example, a user can specify that features that meet some estimated or determined defective criteria should be included in the output data structure.

[0113] a. Example embodiment of candidate feature selection

[0114] In some embodiments, the candidate feature selection process may be applied to process control data that indicates at least the amount of laser energy (e.g., a total amount, an average amount, or the like, as discussed above) delivered to the workpiece 102 (e.g., during the formation of each feature, during a specific step in the formation of each feature, or the like, or any combination thereof). In this case, statistical thresholds that can be used to analyze the process control data may include thresholds such as a maximum positive or negative laser energy deviation (e.g., relative to one or more predetermined set points based on one or more items associated with workpiece information and / or application information). Generally, if the total amount or average amount of laser energy delivered during the formation of a feature (or delivered during a specific step in a process for forming a feature) exceeds the maximum positive laser energy deviation, the resulting feature will likely be defective because too much laser energy is used to form the feature. Features formed using too much laser energy (e.g., blind holes, trenches, recesses, etc.) may be considered defective because material exposed to or otherwise proximate the feature may be undesirably damaged (e.g., melted, eroded, cracked, etc.), or the feature itself may have an undesirable size or shape or have an undesirable taper, overhang, or the like, or any combination thereof. Similarly, if the total or average amount of laser energy delivered during feature formation (or delivered during a particular step in a process for forming a feature) exceeds the maximum negative laser energy deviation, the resulting feature will likely be defective because too little laser energy was used to form the feature. Features formed using too little laser energy (e.g., blind holes, through-holes, trenches, recesses, etc.) may be considered defective because not enough material was removed from the workpiece 102 to form the feature as desired.

[0115] ii. Additional Discussion on Testing

[0116] The position of each candidate feature identified in the output of the candidate feature selection process can be used to control the operation of the third positioner 110 during inspection. In one embodiment, an offset (e.g., in the X and / or Y directions) can be applied to each position to compensate for any lateral offset between the scan lens 112 and the field of view of the camera 113, as 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 camera's field of view, as projected onto the workpiece 102) along a path or trajectory (also referred to herein as an "inspection trajectory"), which can be calculated based on the output of the candidate feature selection process (e.g., at the controller 114, at the remote system 126, or the like, or any combination thereof). In one embodiment, the inspection trajectory used to inspect features formed during machining of the workpiece 102 corresponds to the process trajectory used to inspect the features formed during machining of the workpiece 102. In another embodiment, the inspection trajectory does not correspond to the process trajectory used to inspect the features formed during machining of the workpiece 102. In this case, the inspection trajectory may represent an optimized path or route that enables the camera 113 to capture an image of each candidate feature in the processed workpiece 102 .

[0117] Image data generated by camera 113 during inspection (i.e., representing images captured within the camera's field of view) is output (e.g., as one or more image signals) to controller 114 and can then be interpreted, manipulated, input into an algorithm, or otherwise processed (e.g., at controller 114, at remote system 126, by a user, or the like, or any combination thereof) in any desired manner known in the art or in another suitable manner to determine whether a feature is properly formed (i.e., whether it is defective). It should be understood that image data representing the captured image of any candidate feature can be stored in association with the feature as auxiliary information, which can be used for later analysis, traceability purposes, or the like, or any combination thereof.

[0118] a. Hand motion patterns associated with guided detection and classification

[0119] In one embodiment, the third locator 110 can be manually operated (e.g., via user interaction via the user interface 120, via the remote system 126, or the like, or any combination thereof) to move each candidate feature into the field of view of the camera 113, and the camera 113 can be operated (e.g., via user interaction via the user interface 120, via the remote system 126, or the like, or any combination thereof) to capture an image of each candidate feature within the camera's field of view. The captured image can be displayed (e.g., via a monitor of the user interface 120, the remote system 126, or the like, or any combination thereof), and the user can manually classify the feature associated with the displayed image (e.g., via an input device of the user interface 120 or the remote system 126, etc.) as, for example, defective or non-defective.

[0120] b. Automation patterns associated with guided detection and classification

[0121] In another embodiment, the operation of the third locator 110 and camera 113 can be performed in an automated manner (e.g., by the controller 114, the remote system 126, or the like, or any combination thereof) to perform the detection and classification of each candidate feature. In this embodiment, any suitable image recognition technology can be used to process the image data generated by the detection to classify the detected features as, for example, defective or non-defective. The image can be captured while the third locator 110 is operating to move the candidate feature into the field of view of the camera 113, after the operation of the third locator 110 has completed and the candidate feature is stationary within the field of view of the camera 113, or any combination thereof.

[0122] c. Semi-automatic aspects associated with guided detection and classification

[0123] In yet another embodiment, the operation of the third locator 110 and the camera 113 can be performed in a semi-automated manner to perform the detection and classification of each candidate feature. In this embodiment, the third locator 110 is operated (e.g., by the controller 114, the remote system 126, or the like, or any combination thereof) to cause the camera 113 to capture an image of each candidate feature. The captured image can then be displayed (e.g., by the user interface 120, a monitor of the remote system 126, or the like, or any combination thereof), and the user can manually classify the features associated with the displayed image (e.g., via an input device of the user interface 120 or the remote system 126, etc.) as, for example, defective or non-defective. Figure 2 An example process for collecting manually input classification of candidate features is discussed in more detail.

[0124] Executable Figure 2 A process, such as process 200, is used to facilitate manual classification of candidate features. Figure 2At S202, an image of the detected, unclassified candidate features is displayed to the user (e.g., via user interface 120, via a user interface of remote system 126, etc.). Optionally, other information associated with the candidate features, the identification or location of the candidate features in workpiece 102 may also be displayed to the user (e.g., via user interface 120, via a user interface of remote system 126, etc.). At S204, the user is prompted (e.g., via user interface 120, via a user interface of remote system 126, etc.) to indicate whether they would like to classify the currently displayed candidate features. If the user agrees to classify the candidate features, at S206, the user (e.g., via user interface 120, via a user interface of remote system 126, etc.) classifies the candidate features as (e.g., "defective" or "non-defective") based on the displayed image. If any unclassified candidate features remain, the process described above is repeated. At S208, the user is prompted (e.g., via user interface 120, via a user interface of remote system 126, etc.) to indicate whether they would like to classify another unclassified candidate feature. If another unclassified candidate feature is to be detected, the process discussed above is repeated for the new unclassified candidate feature. If, at S208, no unclassified candidate features remain, the process is terminated. If, at S204, the user indicated that they do not want to classify the currently displayed candidate feature (e.g., via user interface 120, via a user interface of remote system 126, etc.), the process continues to S208.

[0125] iii. Other aspects of guided testing

[0126] It should be appreciated that information regarding the classification of any detected candidate feature—whether classified manually or in an automated manner—may be stored in association with the feature as auxiliary information that may be used for later analysis, traceability purposes, or any combination thereof.

[0127] The embodiments discussed above have so far discussed how the output of the candidate feature 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 another embodiment, the output of the candidate feature selection process can be input to an inspection system (also referred to as a "remote inspection system") that is not part of the apparatus 100 (e.g., as provided in the discussion above). Examples of remote inspection systems that can perform inspection of identified candidate features can include AOI, AXI systems, ICT systems, wafer probe systems, or the like, or any combination thereof.

[0128] In one embodiment, the remote detection system is an embodiment of remote system 126, and thus, controller 114 is operable to transmit the output of the candidate feature selection process to the remote detection system (i.e., remote system 126) via network 124. However, in another embodiment, controller 114 is operable to write the output candidate feature selections to be processed to any machine-readable medium (e.g., to a flash drive plugged into a USB port of communication module 122), or transmit the output candidate feature selections to any other system (e.g., remote system 126), where the output candidate feature selections may be recorded in any suitable or desired machine-readable medium (e.g., a flash drive) connected to remote system 126. The output candidate feature selections as stored by the machine-readable medium may then be input to the remote detection system in any suitable or desired manner.

[0129] XIII. Conclusion

[0130] The foregoing describes embodiments and examples of the present invention and should not be construed as limiting. Although several specific embodiments and examples have been described with reference to the drawings, it will be readily apparent to those skilled in the art that many modifications to the disclosed embodiments and examples, as well as other embodiments, are possible without significantly departing from the novel teachings and advantages of the present invention. Therefore, all such modifications are intended to be included within the scope of the present invention as defined in the claims. For example, it will be understood by those skilled in the art that the subject matter of any sentence, paragraph, example, or embodiment may be combined with some or all of the subject matter of other sentences, paragraphs, examples, or embodiments, unless such combinations are mutually exclusive. The scope of the present invention should therefore be determined by the following claims, and equivalents of the claims are included within the scope of the present invention.

Claims

1. A method comprising: generating a laser energy beam via a laser source; focusing the laser energy beam via a scan lens to form a focused laser energy beam that can be delivered to a workpiece; forming a set of features in the workpiece using the focused beam of laser energy; generating process control data using at least one sensor, the process control data comprising at least one of: a) at least one characteristic of a laser processing tool before, during, or after forming the set of features in the workpiece, or b) at least one characteristic of the workpiece before, during, or after forming the set of features in the workpiece, wherein the laser processing tool comprises the laser source, the scan lens, and a controller; A candidate feature selection process is executed by the controller, whereby: The process control data is processed to estimate whether any of the features formed in the workpiece is defective; and identifying the location of any feature estimated to be defective; as well as An inspection operation is performed by the controller to classify any feature estimated to be defective as defective or non-defective.

2. The method of claim 1, wherein at least a portion of the candidate feature selection process is performed by a remote system.

3. The method of claim 1 , further comprising transmitting an output of the candidate feature selection process to a remote inspection system.

4. The method of claim 1, wherein performing the inspection operation comprises controlling operation of at least one stage to move the workpiece relative to an inspection system.

5. The method of claim 1, wherein the at least one sensor comprises at least one of a laser power meter or a beam characterization tool. The method of claim 1 , wherein the at least one sensor comprises at least one of a temperature sensor or a humidity sensor.

7. The method of claim 1, wherein the at least one sensor comprises at least one of a laser displacement sensor, a confocal laser sensor, an interferometer, an inductive coating thickness gauge, a stylus profilometer, and a touch probe.

8. The method of claim 1, further comprising analyzing data obtained from the inspection operation to classify the features estimated to be defective as defective or non-defective.

9. The method of claim 1, wherein the process control data comprises data representing at least one of: laser energy, peak power, average power, pulse repetition rate, or spot size used to form each feature in the workpiece.

10. The method of claim 1, further comprising generating sensing data of any feature estimated to be defective via at least one second sensor, wherein the detecting operation is based on the sensing data.

11. The method of claim 1 , wherein the candidate feature selection process comprises applying one or more statistical thresholds to the process control data to estimate whether any of the features formed in the workpiece are defective.

12. The method of claim 1, further comprising storing information about the classification of any detected feature in association with the detected feature as auxiliary information.

13. The method of claim 1, wherein the process control data comprises data representing at least one characteristic of an environment surrounding the laser machining apparatus before, during, or after forming the set of features in the workpiece.

14. The method of claim 1, further comprising generating an inspection trajectory based on an output of the candidate feature selection process, wherein the inspection operation is performed by following the inspection trajectory.

Images