TW201904700A - Laser processing apparatus, methods of use and related arrangements - Google Patents

Abstract

A laser processing system can include a laser source configured to generate a beam of laser pulses at an average power of greater than 10 W and a turn mirror disposed in a path of the beam. The turn mirror can include a mirror configured to reflect a first portion of light within the laser pulses and transmit a second portion of the light within the laser pulses, and a mirror mount coupled to the mirror. The mirror mount is configured so as to not be present behind the mirror at a location where the mirror is irradiated with the laser pulses.

Description

 Laser processing equipment, methods of use and related configurations  

The specific examples described herein relate generally to a laser processing apparatus and components thereof, and to methods of using the laser processing apparatus in a manner that facilitates accurate and reliable processing of the workpiece.

Cross-reference to related applications

This application claims the benefit of U.S. Provisional Application Serial No. 62/254,863, filed on Jun.

Laser processing systems are used in a wide variety of applications covering a wide range of performance requirements such as wavelength, power, spot size, working distance, component handling, throughput, accuracy, yield, and the like. In some cases, such as in certain semiconductor processing applications, via drilling applications, etc., the accuracy of the system can have very high requirements and be in the range of only a few microns or even sub-micron levels. Systems with this high beam placement accuracy require that the beam pointing instability of the laser is very small, and in addition the beam path delivery optics does not cause additional beam motion instability. An example of something that can cause the laser beam to move unduly is an unstable turn mirror. A common practice of using a lens to focus a laser beam onto a working surface of a workpiece to be processed (eg, a semiconductor wafer, printed circuit board, etc.) at a working surface is a common laser processing system. For this purpose, the lateral motion (Δ) of the spot at the working surface will be equal to the focal length (F) of the focusing lens multiplied by the beam angle (θ) at the input of the lens (Δ = Fθ). In some systems, such as microscopes, the focal length of a focusing lens (e.g., a microscope objective) can be very small, only a few millimeters. In other systems, such as laser processing systems that use scanning lenses, the focal length of the lens can be tens or hundreds of millimeters. For systems with 100 mm focal length lenses, moving the focused spot laterally by 1.0 micron requires only a beam angle change of 10 microradians (μRad). After considering other factors such as alignment and accuracy of component placement, an additional 1.0 micron spot motion can put the accuracy requirements of the entire system at risk.

In the case of flipping the mirror, the laser beam will be reflected at twice the specular angle. Therefore, changing the beam angle by 10 microradians requires only a change in the mirror angle of 5 microradians. Unfortunately, imparting this small angular change does not cause significant interference with the mirror mount. Adjustable mirror mounts are more susceptible to interference from a greater number of types and types of component parts that make up the mirror mount assembly. The interference can be in the form of vibration, pushing or pulling something of the mounting (eg, cleaning the dry air purification hose) or even small temperature changes. As an example of a change caused by temperature disturbance, it is assumed that the ordinary mirror diameter is one turn (25.4 mm). If the interference causes the edge of the mirror to move (i.e., to tilt the mirror) to exactly 0.127 microns, the mirror angle change is 0.127 μm / 25.4 mm = 5 microradians.

There are many mirror mounts with a solid back. A solid back can be beneficial. It provides protection to the mirror because the solid back will typically be made of a material such as aluminum, which is less brittle than the mirror that may be made of glass. The solid back side can also form a natural safety barrier to any stray light that leaks through the mirror. However, if the mirror mount is made of aluminum (a very common mounting material of CTE = 0.000023 m/m ° C), and if the mirror mount is 5.5 mm thick, the aluminum expands by 0.127 microns and thus gives 5 micro A change in the mirror angle of the arc will only require a temperature change of 1 °C on one edge of the mirror mount (relative to the opposite edge of the mirror mount).

In high-accuracy laser processing systems, it is important to know all the heat sources and their potential to influence the items in the beam path. The mechanism used to cool the part can also affect its sensitivity to the heat source. One source of heat for many mirror mounts can be the laser beam itself. Although it is quite common to require a specular surface with a reflectance of 99.5% or even higher, there will still be a small amount of light transmitted through the mirror. For systems with a laser beam power <1W, the total amount of transmitted light is likely to be negligible. However, in higher power systems (eg, where the laser beam power is about 30 W or greater), 0.5% of the power is 150 mW. If a 150 mW laser beam is transmitted through the mirror and hits the back of the mirror mount, most of the laser beam can be absorbed by the mount, converted to heat and cause the temperature of the mount to increase by about one degree. Depending on the material and geometry of the mirror mount assembly, orientation, and the available cooling mechanism, the mirror will experience a change in tilt that can cause undesirable beam steering problems. One way to prevent the mirror from degrading the beam steering accuracy of a laser processing system caused by beam heating is to turn the laser on and wait until the thermal balance is established. Any alignment or processing can then be performed. However, this can be disadvantageous because the time required to reach thermal equilibrium can be undesirably long (i.e., about a few minutes to a few 10 minutes) and will need to be whenever the laser beam is turned on (even Execute after temporary shutdown.

Another way to address the problem of reduced beam steering accuracy caused by beam heating involves adding a motor or other mechanism to adjust the mirror tilt angle to compensate for beam heating on the fly as soon as the laser is energized. This approach has several drawbacks, such as the need to provide some kind of indicator to know how much to adjust, which axis to adjust, and how long to perform the compensation adjustment. Yet another way to address (or reduce the severity of) reduced beam steering accuracy caused by beam heating involves the use of a mirror having a reflectance well above 99.5%. However, mirrors with extremely high reflectivity have the potential for higher cost and/or preparation time. There is also the possibility of batch differences.

Sometimes, when machining a workpiece using a laser machining system (eg, when scoring or cutting a workpiece such as a semiconductor wafer), features are well maintained for each of a series of workpieces to be processed (eg, Placement of the wire/saw) can be important. Errors in spot placement at the workpiece can be caused by changes in the hardware of the system, caused by problems with proper alignment to the workpiece to be machined, or even by mistakes created to process the workpiece recipe. If no errors are detected, the workpiece can be damaged or lost in its entirety, sometimes at a considerable cost. Vision-based metrology is currently available as a dedicated metrology tool or incorporated into the system itself for use in many laser processing systems. Conventional vision-based metrology techniques typically utilize edge discovery algorithms that often use low-angle illumination to help highlight edges, or simple image-limiting algorithms to help identify specific visual changes in the image of the grain track, which should Represents the edge of a feature (eg, a scribe or kerf) formed in a workpiece (eg, a semiconductor wafer). Other non-visual-based metrology techniques, such as laser triangulation sensors, can be used to measure height changes, and thus help determine the location of features (eg, scribing or kerf), but with such non-visual-based weights and measures The resolution associated with technology is often limited (for example, in the case of a laser triangulation sensor, it is limited by the spot size that can be produced by a laser triangulation system).

A specific embodiment of the invention can be broadly characterized as a laser processing system: a laser source configured to generate a beam of laser pulses having an average power greater than 10 W; The mirror is flipped and placed in one of the paths of the beam. The flip mirror may include a mirror configured to reflect a first portion of the light within the laser pulses and transmit a second portion of the light within the laser pulses, and coupled to one of the mirrors Mirror mount. The mirror mount is configured to be absent from the mirror at a location where the mirror is irradiated by the laser pulses.

100‧‧‧Laser processing system

101‧‧‧Workpiece

101a‧‧‧Workpiece surface

102‧‧‧Laser source

104‧‧‧beam positioner

110‧‧‧Scan lens

112‧‧‧ Controller

114‧‧‧ camera

116‧‧‧beam path

108‧‧‧Workpiece positioner

Fig. 1 schematically illustrates an apparatus for processing a workpiece according to one specific example.

2 and 3 are perspective views taken from the back of the flip mirror according to some embodiments, and the flip mirror can be incorporated into the apparatus shown in FIG.

4 through 7 schematically illustrate an exemplary procedure for facilitating alignment of workpieces within the apparatus shown in FIG. 1 in accordance with one embodiment.

I. Preface

Example specific examples are described herein with reference to the accompanying drawings. The size, position, etc. of components, features, elements, etc., and any distances therebetween, are not necessarily to scale, but are exaggerated for clarity, in the drawings.

The terminology used herein is for the purpose of describing particular example embodiments and is not intended to be limiting. As used herein, the singular forms "" It is to be understood that the term "comprises", when used in the specification, is intended to mean the presence of the features, the whole, the steps, the operation, the components and/or The presence or addition of components, components, and/or groups thereof. The range of values includes both the upper and lower limits of the range and any sub-ranges in the Terms such as "first", "second" and the like are used to distinguish one element from another element unless otherwise indicated. For example, one node may be referred to as a "first node," and similarly, another node may be referred to as a "second node," or vice versa. The section headings used herein are for organizational purposes only and are not to be construed as limiting.

Unless otherwise indicated, the terms "about", "upper and lower" and the like mean that quantity, size, formulation, parameters, and other quantities and characteristics are not, and need not be precise, and may be approximate and/or larger or smaller, as desired. To reflect tolerances, conversion factors, rounding, measurement errors, and the like, as well as other factors known to those skilled in the art.

Spatially relative terms such as "lower", "lower", "lower", "above" and "upper" and the like may be used herein to describe one element or feature and another element or feature. Relationship, as illustrated in the figure. It will be appreciated that the spatially relative terms are intended to encompass different orientations other than the orientation depicted in the drawings. For example, if the items in the figures are turned over, the elements described as "under the other elements or features" or "under the other elements or features" will be &quot;above&quot; Therefore, the exemplary term "below" can encompass both the "above" and "under" orientations. The object may be otherwise oriented (eg, rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may be interpreted accordingly.

The same numbers always refer to the same component. Accordingly, the same or similar numerals may be described in reference to the other figures, even if the figures are not mentioned in the corresponding drawings. Also, elements that are not indicated by reference numerals may be described with reference to the other drawings.

It should be understood that many different forms and specific examples are possible without departing from the spirit and scope of the invention, and therefore, the invention should not be construed as limited. Rather, these examples and specific examples are provided so that this invention will be thorough and complete, and the scope of the invention will be fully conveyed by those skilled in the art.

II. System Overview

Figure 1 schematically illustrates a laser processing system configured to machine a workpiece in accordance with one embodiment. In general, the processing is accomplished in whole or in part by irradiating the workpiece with laser radiation for heating, melting, evaporating, ablation, cracking, fading, polishing, roughening, carbonizing, foaming to form a workpiece. One or more materials, or otherwise modified to form one or more properties or characteristics of one or more materials of the workpiece (eg, chemical composition, crystal structure, electronic structure, microstructure, nanostructure, density, viscosity, refraction) Rate, permeability, relative permittivity, etc.). These materials may be present at the outer surface of the workpiece before or during processing, or may be located within the workpiece before or during processing (ie, not present at the outer surface of the workpiece). Specific examples of processing that can be performed by the illustrated apparatus include via drilling, perforation, welding, scoring, engraving, marking (eg, surface marking, subsurface marking, etc.), cutting, laser induced forward transfer, cleaning Bleaching, bright pixel maintenance (eg, color filter darkening, modification of organic light-emitting diode materials, etc.), removal of coatings, surface winding (eg, roughening, smoothing, etc.), smelting, cladding or deposition , or a similar treatment thereof, or any combination thereof. Thus, features that may be formed on or in the workpiece as a result of processing may include openings, slots, vias (eg, blind vias, vias, slit vias), grooves, trenches, dicing streets, kerfs, a recessed region, a conductive trace, an ohmic contact, a photoresist pattern, a mark (eg, composed of one or more regions in or on a workpiece having one or more visual, textual, qualitatively distinguishable characteristics, etc.) ), or an analog thereof, or any combination thereof. Such features may have any suitable or desired shape (eg, circular, elliptical, square, rectangular, triangular, toroidal, or the like, or any combination thereof) when formed into openings, vias, and the like.

The workpieces that can be processed by the apparatus can be generally characterized as metals, polymers, ceramics or composites. Specific examples of workpieces that can be processed include the following: printed circuit board (PCB) panels (also referred to herein as "PCB panels"), PCBs, flexible printed circuits (flexile printed circuits) ; FPC), integrated circuit (IC), IC package (ICP), light-emitting diode (LED), LED package, semiconductor wafer, electronic or optical device substrate (for example, by Al) Substrate formed of ₂ O ₃ , AlN, BeO, Cu, GaAS, GaN, Ge, InP, Si, SiO ₂ , SiC, Si1-xGex (where 0.0001 < x <0.9999), or an analogue thereof, or any combination or alloy thereof ), components for microfluidic devices, touch sensors, electronic displays formed of plastic, glass (eg, unreinforced, thermally strengthened, chemically strengthened, or otherwise reinforced), quartz, sapphire, plastic, tantalum, etc. (for example, a substrate on which a TFT, a color filter, an organic LED (OLED) array, a quantum dot LED array or the like or any combination thereof), a cover glass, a lens, a mirror, a screen protector, and the like are formed , turbine blades, powder, film, foil, , molds, fabrics (woven, felted, etc.), surgical instruments, medical implants, consumer packaged goods, shoes, bicycles, automobiles, automotive or aerospace components (eg, frames, body panels, etc.), electrical appliances ( For example, a microwave oven, an oven, a refrigerator, etc., a device housing (eg, a watch, a computer, a smart phone, a tablet, a wearable electronic device, or the like, or any combination thereof).

Thus, the processable material comprises: one or more metals (eg, Al, Ag, Au, Cu, Fe, In, Mg, Pt, Sn, Ti, or the like or combinations or alloys thereof); conductive metal oxides ( For example, ITO or the like), a transparent conductive polymer, a semiconductor, a ceramic, a wax, a resin, an inorganic dielectric material (for example, used as an interlayer dielectric structure such as cerium oxide, cerium nitride, cerium oxynitride or the like or Any combination thereof, a low-k dielectric material (eg, methyl sesquioxanes (MSQ), hydroquinone sesquioxanes (HSQ), fluorinated tetraethyl orthoformate (FTEOS) or the like or Any combination thereof), an organic dielectric material (for example, SILK, benzocyclobutene, Nautilus (all manufactured by Dow), polytetrafluoroethylene (manufactured by DuPont), FLARE (manufactured by Allied Chemical), or the like or Any combination thereof), glass fiber, polymeric material (polyamide, polyimine, polyester, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyphenylene sulfide) Ether, polyether oxime, polyether oximine, polyether ether ketone, liquid crystal polymer, acrylonitrile butadiene styrene and any compound thereof Matter or alloy), leather, paper, cumulative materials (for example, Ajinomoto accumulation film, also known as "ABF", etc.), glass-reinforced epoxy resin laminate (for example, FR4), prepreg, or the like Or any composite, laminate or other combination.

Referring to FIG. 1, laser processing system 100 includes a laser source 102 for generating laser pulses, a beam positioner 104, a workpiece positioner 108, a scanning lens 110, a controller 112, and optionally a camera 114. Although not shown, the laser processing system 100 also includes one or more optical components (eg, beam expanders, beam shapers, apertures, harmonic generating crystals, filters, collimators, lenses, mirrors, polarizers) , a wave plate, a diffractive optical element, or the like, or any combination thereof, to one or more beam paths extending between the laser source 102 and the scanning lens 110 produced by the laser source 102 ( For example, the laser pulses of beam path 116) are focused, expanded, collimated, shaped, polarized, filtered, segmented, combined, or otherwise modified, adjusted, and guided. Laser pulses transmitted through the scanning lens 110 propagate along the beam axis for delivery to the workpiece 101. The laser pulse is typically delivered to be incident on an area of the workpiece surface 101a to be processed. The area irradiated by the delivered laser pulse is referred to herein as a "processing spot", a "spot position" or more simply a "spot" and encompasses the area of the beam axis that traverses the workpiece 101.

Although not shown, system 100 includes one or more flip mirrors disposed in beam path 116 (eg, between laser source 102 and beam positioner 104). Any flip mirror can be provided as a fixed flip mirror or an adjustable flip mirror. The orientation of the fixed flip mirror is typically fixed (or at least substantially fixed) after installation in system 100. The orientation of the adjustable flip mirror can be adjusted by means of a manually adjustable screw, a piezoelectric actuator, or the like, or any combination thereof (eg, to tilt or tilt the mirror about one or more axes). In general, the flip mirror includes, as its component, a mirror for reflecting the laser pulses (i.e., redirecting the beam path 116) and a mirror mount for coupling the mirror to the system 100.

A. Laser source

In one specific example, laser source 102 operates to generate a laser pulse. Thus, the laser source 102 can include a pulsed laser source, a QCW laser source, or a CW laser source. Where the laser source 102 comprises a QCW or CW laser source, the laser source 102 may optionally include a pulse gating unit (eg, an acousto-optic (AO) modulator (AOM), beam chopping) A device that emits laser radiation that is temporally modulated from a QCW or CW laser source. The laser pulses generated by the laser source 102 can be characterized as having ultraviolet (UV), visible (eg, purple, blue, green, red, etc.) or infrared (IR) ranges or any combination thereof in the electromagnetic spectrum. One or more wavelengths in one or more. The laser light in the UV range of the electromagnetic spectrum may have one or more wavelengths in the range of 150 nm (or up and down) to 385 nm (or up and down), such as 157 nm, 200 nm, 334 nm, 337 nm, 351 nm, 380 nm, etc., or the like. The value between any of them. The laser light in the visible green range of the electromagnetic spectrum may have one or more wavelengths in the range of 500 nm (or upper and lower) to 570 nm (or upper and lower), such as 511 nm, 515 nm, 530 nm, 532 nm, 543 nm, 568 nm, etc., or the like. The value between any of the values. The laser light in the IR range of the electromagnetic spectrum may have one or more wavelengths in the range of 750 nm (or upper and lower) to 15 μm (or upper and lower), such as 700 nm to 1000 nm, 752.5 nm, 780 nm to 1060 nm, 799.3 nm, 980 nm, 1047 nm. Values between 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 any of these values .

If the beam of incident light comprises a series of laser pulses, the laser pulses may have a pulse duration in the range of 10fs to 900ms (ie, based on the full-width of the half-wave height of the optical power in the pulse (full-width) At half-maximum, FWHM) comparison time). However, it should be understood that the pulse duration can be made less than 30 fs or greater than 900 ms. Therefore, the at least one laser pulse may have greater than or equal to 10fs, 15fs, 30fs, 50fs, 100fs, 150fs, 200fs, 300fs, 500fs, 700fs, 750fs, 850fs, 900fs, 1ps, 2ps, 3ps, 4ps, 5ps, 7ps, 10ps, 15ps, 25ps, 50ps, 75ps, 100ps, 200ps, 500ps, 1ns, 1.5ns, 2ns, 5ns, 10ns, 20ns, 50ns, 100ns, 200ns, 400ns, 800ns, 1000ns, 2μs, 5μs, 10μs, 50μs, 100μs One of the values of the pulse duration between 300μs, 500μs, 900μs, 1ms, 2ms, 5ms, 10ms, 20ms, 50ms, 100ms, 300ms, 500ms, 900ms, 1s, etc. or any of these values. Likewise, the at least one laser pulse can have less than 1 s, 900 ms, 500 ms, 300 ms, 100 ms, 50 ms, 20 ms, 10 ms, 5 ms, 2 ms, 1 ms, 300 ms, 900 μs, 500 μs, 300 μs, 100 μs, 50 μs, 10 μs, 5 μs, 1 μs. 800ns, 400ns, 200ns, 100ns, 50ns, 20ns, 10ns, 5ns, 2ns, 1.5ns, 1ns, 500ps, 200ps, 100ps, 75ps, 50ps, 25ps, 15ps, 10ps, 7ps, 5ps, 4ps, 3ps, 2ps, One pulse duration of values between 1 ps, 900 fs, 850 fs, 800 fs, 750 fs, 700 fs, 500 fs, 300 fs, 200 fs, 150 fs, 100 fs, 50 fs, 30 fs, 15 fs, 10 fs, etc., or any of these values.

If the beam of incident light comprises a series of laser pulses, the laser pulses may have an average power in the range of 5 mW to 50 kW. However, it should be understood that the average power can be made less than 5 mW or greater than 50 kW. Therefore, the laser pulse may have 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. One of the values between 18W, 25W, 30W, 50W, 60W, 100W, 150W, 200W, 250W, 500W, 2kW, 3kW, 20kW, 50kW, etc. or any of these values. Similarly, the laser pulse can have less than 50 kW, 20 kW, 3 kW, 2 kW, 500 W, 250 W, 200 W, 150 W, 100 W, 60 W, 50 W, 30 W, 25 W, 18 W, 15 W, 10 W, 7 W, 6 W, 5 W, 4 W, 3 W. Average power of one of the values between 2W, 1W, 800mW, 500mW, 300mW, 100mW, etc. or any of these values.

The laser pulse can be output by the laser source 102 at a pulse repetition rate in the range of 5 kHz to 1 GHz. However, it will be appreciated that the pulse repetition rate can be made less than 5 kHz or greater than 1 GHz. Thus, the laser pulse can be greater than or equal to 5 kHz, 50 kHz, 100 kHz, 250 kHz, 500 kHz, 800 kHz, 900 kHz, 1 MHz, 2 MHz, 10 MHz, 20 MHz, 50 MHz, 70 MHz, 100 MHz, 150 MHz, 200 MHz, 250 MHz, 300 MHz, by the laser source 102. One pulse repetition rate output of 350 MHz, 500 MHz, 550 MHz, 700 MHz, 900 MHz, 2 GHz, 10 GHz, and the like. Similarly, the laser pulse can be less than 10 GHz, 2 GHz, 1 GHz, 900 MHz, 700 MHz, 550 MHz, 500 MHz, 350 MHz, 300 MHz, 250 MHz, 200 MHz, 150 MHz, 100 MHz, 90 MHz, 70 MHz, 50 MHz, 20 MHz, 10 MHz, 2 MHz from the laser source 102. One pulse repetition rate output of 1 MHz, 900 kHz, 800 kHz, 500 kHz, 250 kHz, 100 kHz, 50 kHz, 5 kHz, and the like. In another embodiment, the laser source 102 is operable to generate one or more laser pulses on demand rather than at any particular pulse repetition rate.

In addition to wavelength, pulse duration, average power, and pulse repetition rate, the laser pulses delivered to workpiece 101 may also be characterized by one or more other characteristics, such as pulse energy, peak power, etc., which may be selected. (eg, based on one or more other characteristics, such as wavelength, pulse duration, average power, and pulse repetition rate), sufficient to process the optical intensity of the workpiece 101 or its components (measured in W/cm ² ), The workpiece 101 at the processing spot is irradiated with a quantity (in J/cm ² ) or the like.

Examples of types of lasers that can be used to generate the aforementioned incident light beam can be characterized as gas lasers (eg, carbon dioxide lasers, carbon monoxide lasers, excimer lasers, etc.), solid state lasers (eg, Nd:YAG lasers). Etc., rod laser, fiber laser, photonic crystal rod/fiber laser, passive mode locked solid block or fiber laser, dye laser, mode-locked diode laser, pulsed laser (eg, ms, Ns, ps, fs pulsating laser), CW laser, QCW laser, or the like or any combination thereof. Specific examples of lasers that can be used to generate the aforementioned incident light beam include one or more of the following: BOREAS, HEGOA, SIROCCO, or CHINOOK series lasers manufactured by EOLITE; PYROFLEX series lasers manufactured by PYROPHOTONICS; PLAADIN advanced 355 or DIAMOND series (for example, DIAMOND E, G, J-2, J-3, J-5 series) lasers manufactured by COHERENT; PULSTAR or FIRESTAR series lasers manufactured by SYNRAD; TRUFLOW series lasers (eg, TRUFLOW 2000, 2700, 3000, 3200, 3600, 4000, 5000, 6000, 7000, 8000, 10000, 12000, 15000, 20000), TRUCOAX series lasers (eg TRUCOAX 1000) or TRUDISK, TRUPULSE, TRUDIODE, TRUFIBER or TRUMICRO series lasers, all manufactured by TRUMPF; FCPA μJEWEL or FEMTOLITE series lasers manufactured by IMRA AMERICA; TANGERINE and SATSUMA series lasers (and MIKAN and T-PULSE series oscillators manufactured by AMPLITUDE SYSTEMES) ); CL, CLPF, CLPN, CLPNT, CLT, ELM, ELPF, ELPN, ELPP, ELR, ELS, FLPN, FLPNT, FLT, GLPF, GLPN, GLR, HLPN, HLPP, RFL, TLM, TLPN manufactured by IPG PHOTONICS , TLR, ULPN, ULR, VLM, VLPN, YLM, YLPF, YLPN, YLPP, YLR, YLS, FLPM, FLPMT, DLM, BLM or DLR series lasers (eg, including GPLN-100-M, GPLN-500-QCW , GPLN-500-M, GPLN-500-R, GPLN-2000-S, UPLN-355-M, UPLN-355-R, UPLN-355-QCW-R, etc., or the like or any combination thereof.

B. Beam locator

The beam positioner 104 is operable to diffract, reflect, refract or otherwise or otherwise combine the laser energy beam propagating along the beam path 116 from the output of the beam imaging system 104 to impart a beam path 116 relative to the scan. Movement of the lens 110. In general, beam positioner 104 is configured to impart movement of the beam axis relative to workpiece 101 along the X and Y axes (or directions) such that the processing spot can be scanned, moved, or otherwise positioned within the field. The field (eg, from the scanning lens 110) is projected onto the workpiece 101. Although not shown, the X-axis (or X-direction) is understood to mean an axis (or direction) orthogonal to the Y and Z axes (or directions) illustrated.

The beam positioner 104 can be provided as a micro-electro-mechanical-system (MEMS) mirror or mirror array, an AO deflector (AOD) system, an electro-optic deflector (EOD) system, a fast turning mirror (fast-steering mirror; FSM) components (eg, piezoelectric actuators, electrostrictive actuators, voice coil actuators, etc.), galvanometer mirror systems (eg, including two galvanometer mirror components, One of the galvanometer mirror assemblies is configured to impart movement in the X direction relative to the workpiece 101 and the other galvanometer mirror assembly is configured to impart movement in the Y direction relative to the workpiece 101, or Similar or any combination thereof.

D. Workpiece locator

The workpiece positioner 108 is operable to move the workpiece 101 relative to the scanning lens 110 in the X, Y, and/or Z directions. Thus, within the range in which workpiece positioner 108 moves workpiece 101 in the X and/or Y direction, workpiece positioner 108 is configured to move different regions of workpiece 101 into and out of the field projected by scan lens 110. In one specific example, the workpiece positioner 108 is provided as one or more linear platforms (eg, each can impart translational movement along the X, Y, and/or Z directions of the workpiece 101), one or more rotating platforms ( For example, each can impart a rotational movement of the workpiece 101 about an axis parallel to the X, Y, and/or Z directions, or the like, or any combination thereof. In one embodiment, the workpiece locator 108 includes an X platform for moving the workpiece 101 in the X direction and a workpiece 101 supported by the X platform (and thus movable in the X direction by the X platform) Y platform moving along the Y direction. The laser processing system 100 can optionally be coupled to a chuck (not shown) of the workpiece positioner 108 that can be clamped, secured, held, fastened, or otherwise supported to the chuck. Although not shown, the laser processing system 100 can also include an optional base that supports the workpiece positioner 108.

As described so far, the laser processing system 100 employs a so-called "stacked" positioning system in which the positions of components such as the beam positioner 104, the scanning lens 110, etc., remain stationary relative to the workpiece 101 within the laser processing system 100 (eg, The workpiece is moved via the workpiece positioner 108 via one or more supports, frames, etc., as is known in the art. In another embodiment, and although not shown, one or more auxiliary locators (eg, one or more linear rotating platforms, or the like or any combination thereof) may be provided to enable, for example, beam locator 104, One or more components of the scanning lens 110 and the like are moved, and the workpiece 101 can remain stationary (in this case, the workpiece positioner 108 can be omitted).

In yet another embodiment, the laser processing system 100 can use a split axis positioning system in which one or more components, such as beam locator 104, scan lens 110, etc., are supported by one or more auxiliary locators (not shown) Show) positioning. In this particular example, one or more linear or rotating platforms are configured and configured to move one or more components, such as beam locator 104, workpiece locator 108, scanning lens 110, etc., and workpiece locator 108 It is configured and configured to move the workpiece 101. Some examples of split-axis positioning systems that may be beneficially or advantageously used in laser processing system 100 include any of the split-axis positioning systems disclosed in U.S. Patent Nos. 5,751,585, 5,798,927. No. 5,847,960, 6,706,999, 7, 605, 343, 8, 680, 430, 8, 847, 113, or U.S. Patent Application Publication No. 2014/0083983, or any combination thereof, each of which is incorporated by reference in its entirety. The manner is incorporated herein.

In another embodiment, one or more components, such as beam locator 104, scanning lens 110, etc., can be carried by an articulated multi-axis robotic arm (eg, a 2, 3, 4, 5, or 6 axis arm). In this particular example, beam aligner 104 and/or scan lens 110 may optionally be carried by an end effector of the robotic arm. In yet another embodiment, the workpiece 101 can be carried directly on the end effector of the articulated multi-axis robotic arm (ie, without the workpiece positioner 108). In yet another embodiment, the workpiece positioner 108 can be carried on an end effector of an articulated multi-axis robotic arm.

D. Scanning lens

Scanning lens 110 (eg, provided as a simple lens or a compound lens) is typically configured to focus the laser energy directed along beam path 116 to produce a beam waist. Scanning lens 110 can be provided as an f-theta lens, a telecentric lens, a conical lens, or the like, or any combination thereof. In one embodiment, the scanning lens 110 is provided as a fixed focal length lens and coupled to a lens actuator (not shown) that is configured to move the scanning lens 110 (eg, thereby The beam axis changes the position of the beam waist). For example, the lens actuator can be provided as a voice coil configured to linearly translate the scanning lens 110 in the Z direction. In another embodiment, the scanning lens 110 is provided as a variable focus lens (eg, a zoom lens, or a so-called "liquid lens" that is currently provided by COGNEX, VARIOPTIC, etc.), and the variable focus lens can Move (eg, via a lens actuator) to change the position of the beam waist along the beam axis.

E. Controller

In general, controller 112 (eg, via one or more wired or wireless communication links, such as USB, Ethernet, Firewire, Wi-Fi, RFID, NFC, Bluetooth, Li-Fi, or the like) Or any combination thereof) communicatively coupled to one or more components of the laser processing system 100, such as a laser source 102, a beam positioner 104, a workpiece positioner 108, a lens actuator, etc., and the one or The plurality of components thus operate in response to outputting one or more control signals by controller 112.

Generally, controller 112 includes one or more processors configured to generate control signals upon execution of an instruction. The processor can be provided as a programmable processor configured 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 can be implemented as software, firmware, etc., or any suitable form of circuitry, including a programmable logic device (PLD), a field-programmable gate array (field-programmable gate array; FPGA), field-programmable object array (FPOA), application-specific integrated circuit (ASIC) - including digital, analog and mixed analog/digital circuits - or the like or Any combination of them. Execution of instructions may be performed on one processor, distributed among multiple processors, across a processor within a device, or across a network of devices, or the like, or any combination thereof.

In one specific example, controller 112 includes tangible media, such as computer memory, that can be accessed by a processor (e.g., via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (eg, magnetic tape, hard disk drive, etc.), optical disks, volatile or non-volatile semiconductor memory (eg, RAM, ROM, reverse flash memory). , reverse or flash memory, SONOS memory, etc., etc., and can be accessed locally, remotely (eg, across a network) or in a combination thereof. Generally, instructions can be stored as computer software (eg, executable code, files, instructions, etc., library files, etc.), which can be easily produced by the industry (according to the description provided herein), for example, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, etc. Computer software is typically stored in one or more data structures that are transferred by computer memory.

Although not shown, one or more drivers (eg, RF drivers, servo drives, line drivers, power supplies, etc.) can be communicatively coupled to, for example, laser source 102, beam positioner 104, workpiece positioner 108, lens actuators. Wait for the input of one or more components. In one specific example, each driver typically includes an input to which the controller 112 is communicatively coupled, and the controller 112 is thereby operable to generate one or more control signals (eg, trigger signals, etc.), the one or A plurality of control signals can be transmitted to the inputs of one or more drivers associated with one or more components of the laser processing system 100. Accordingly, components such as laser source 102, beam positioner 104, workpiece positioner 108, lens actuators, and the like, are responsive to control signals generated by controller 112.

In another embodiment, and although not shown, one or more additional controllers (eg, component-specific controllers) may be communicatively coupled to the input of the drive, which is communicatively coupled to, for example, a mine Components of the source 102, beam positioner 104, workpiece positioner 108, lens actuator, etc. (and thus associated with the assembly). In this particular example, each component specific controller can be communicatively coupled, and controller 112 is operative to generate one or more control signals in response to receiving one or more control signals from controller 112 (eg, The trigger signal, etc., the one or more control signals can then be transmitted to the input of the driver to which the controller is communicatively coupled. In this particular example, the configuration of the component specific controller can be similar to that described with respect to controller 112.

In another specific example of providing one or more component specific controllers, a component specific controller associated with one component (eg, laser source 102) can be communicatively coupled to one component (eg, a beam positioner) 104, etc.) associated component specific controller. In this particular example, one or more of the component-specific controllers are operative to generate one or more control signals in response to one or more control signals received from one or more other component-specific controllers (eg, Trigger signal, etc.).

E. Camera

When included in the laser processing system 100, the camera 114 is typically configured to capture an image of the workpiece 101 and transmit image data representative of the captured image to the controller 112. Camera 114 may be provided as a digital camera (eg, a CCD camera, a CMOS camera, or the like, or any combination thereof), and may be configured and configured such that the field of view of camera 114 is completely off-screen. In another embodiment, camera 114 is configured and configured to cause the field of view of camera 114 to be completely within the field of view. In yet another embodiment, camera 114 is configured and configured such that the field of view of camera 114 is only partially within the field of view. When the field of view of the camera 114 is completely outside the field (or only partially within the field), the workpiece positioner 108 can be configured to position any area of the workpiece 101 that can be positioned within the field, as viewed by the camera 114. Inside the venue.

III. Specific examples related to beam stabilization

As mentioned above, imparting this small angular change does not cause significant interference with the mirror mount. Figure 2 shows an example of a flip/tilt adjustable mirror mount. Although it is known that the portion of the mirror mount that rests immediately after the mirror surface heats up when the mirror surface is irradiated by the laser pulse, it is not accurately known which component or components of the mirror mount are deformed (eg, due to The coefficient of thermal expansion of the mirror mount) and the undesired tilt of the mirror. It has also been observed in one case that if the mirror mount is oriented such that it rises away from the mounting, but is at least partially mirrored (ie, the mirror points upward), the heat rises away from the mounting (ie, the mirror) Pointing down), the amount of non-mirror tilt is increased.

The solution to the heat problem discussed above with respect to Figure 2 is to provide a flip mirror having a mirror mount that does not exist immediately after the area of the mirror that is desired or expected to be irradiated with a laser pulse. Figure 3 illustrates an example of such a mirror mount. With respect to this method, any laser light transmitted through the mirror will heat a region of the mirror mount that is not immediately after the irradiated region of the mirror, and/or will propagate until the laser illumination is off the beam path 116. On some other component farther away. Thus, a mirror mount such as the mirror mount shown in Figure 3 can reduce the risk of undesired tilting of the mirror. Furthermore, a flip mirror such as the flip mirror shown can be relatively simple and less expensive than an automated beam steering system. In one embodiment, when the laser source 102 produces a beam of laser pulses having an average power greater than or equal to 10 W, 20 W, 30 W, 40 W, etc., or between any of these values, such as in FIG. The flip mirror of the flip mirror shown can be used in system 100.

IV. Specific examples related to workpiece alignment

As mentioned above, when laser scribing or cutting a workpiece such as a semiconductor wafer, it may be important to ensure that the placement of features (e.g., scribing, sawing, etc.) is well maintained for each workpiece. In one specific example (eg, where system 100 includes camera 114), a Z-stacking technique (also referred to as extended depth of focus technology) can be used to accurately determine the location of features in the workpiece. Z-stacking is a vision-based approach for both photography and microscopy to provide images with a depth of focus that appears to be far superior to conventional optical capabilities. In the case of a Z stack, a plurality of images are collected using the camera 114 in a manner that traverses a series of focal lengths (see, for example, FIG. 4) without changing the position of the workpiece relative to the camera 114. This is called "Z stacking". For each pixel in the images, the regional image gradient is calculated by any suitable technique. This calculation is performed for the same pixel location throughout all images in the Z stack (see, eg, Figure 5). The "best focus" of an image or region within an image can often be determined by the peak in the image gradient (i.e., the contrast between the visible features of an image is highest at the time of focusing). Thus, by comparing the image gradients of the same pixel location throughout all of the images in the Z stack (see, for example, Figure 6), it is possible to determine which image within the stack provides the best focus for the pixel location in the analysis. By interpolating between data points, it is possible to achieve a resolution that exceeds the resolution provided by the spacing of the Z stack. When performing this same analysis on all pixels in the image, you can determine the best image in the stack for all pixel locations, allowing you to construct a composite image where each pixel represents the best focus of the position in the Z stack . For many applications, this added depth image is the primary output. However, knowing which image in the Z stack represents the best focus of a particular pixel means that you know the height of the position (ie, the height of the position as measured along the Z axis), and if known in the image For each pixel's information, you can construct the height/profile of the scene (see, for example, Figure 7). Once the height map has been generated, the line edges can be found by looking at the higher gradient regions in the height data (i.e., the regions with steeper slopes). Knowing that the edge of the kerf should be roughly linear, and knowing what typical scenes can look the same (for example, both the horizontal and vertical kerf edges are present when checking the intersection) can also help identify the edges. Images processed using the described techniques can be collected using the same cameras and illuminators for other typical system activities such as visual alignment. No extra hardware is required. This situation is beneficial from a cost perspective.

Although computationally intensive, one of the primary benefits of the Z-stacking technique described above is the detection of only one edge of a feature (eg, a scribe or kerf) using only height data. From time to time, there is visual content of the scene (for example, areas that can be bright or dark); the only important aspect of visual content is how the visual content changes with position within the Z stack, which affects the height of the collection. The quality of the information. This means that the same algorithm can be used for different product types (which can have significant visual differences) without the need to change or tune the parameters.

V. Conclusion

Specific examples and examples of the invention are described above and should not be construed as limiting. While the invention has been described with respect to the specific embodiments of the embodiments of the invention In the case of advantages, it is possible. Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the scope of the claims. For example, those skilled in the art will appreciate that the subject matter of any sentence, paragraph, example, or example can be combined with some or all of the other sentences, paragraphs, examples, or specific examples, unless such combinations are Repulsed. The scope of the invention is therefore intended to be determined by the scope of the appended claims

Claims (9)

 A laser processing system comprising: a laser source configured to generate a beam of laser pulses having an average power greater than 10 W; and a flip mirror disposed in a path of the beam, the flipping The mirror includes: a mirror configured to reflect a first portion of the light within the laser pulses and to transmit a second portion of the light within the laser pulses; and mirror mounted to one of the mirrors And wherein the mirror mount is not present behind the mirror at a location where the mirror is irradiated by the laser pulses.    The laser processing system of claim 1, wherein the average power is greater than 18W.    The laser processing system of claim 2, wherein the average power is greater than 25W.    The laser processing system of claim 3, wherein the average power is equal to 30W.    The laser processing system of claim 3, wherein the average power is greater than 30W.    The laser processing system of any one of claims 1 to 5, further comprising: a scanning lens disposed in a beam path along which the laser beam propagates; and the beam a locator disposed within the beam path between the laser source and the scanning lens.    The laser processing system of claim 6, wherein the beam positioner comprises a galvanometer mirror system.    The laser processing system of claim 6, wherein the beam positioner comprises an acousto-optic deflector system.    The laser processing system of claim 6, wherein the flip mirror is oriented to face down.