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WO2007116124A1 - Procédé destiné à ajuster un seuil d'ablation - Google Patents

Procédé destiné à ajuster un seuil d'ablation Download PDF

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Publication number
WO2007116124A1
WO2007116124A1 PCT/FI2007/000094 FI2007000094W WO2007116124A1 WO 2007116124 A1 WO2007116124 A1 WO 2007116124A1 FI 2007000094 W FI2007000094 W FI 2007000094W WO 2007116124 A1 WO2007116124 A1 WO 2007116124A1
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WIPO (PCT)
Prior art keywords
laser
ablated
ablation
target
target material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/FI2007/000094
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English (en)
Inventor
Reijo Lappalainen
Jari Ruuttu
Vesa MYLLYMÄKI
Juha MÄKITALO
Lasse Pulli
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Picodeon Ltd Oy
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Picodeon Ltd Oy
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Filing date
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Publication of WO2007116124A1 publication Critical patent/WO2007116124A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/24—Vacuum evaporation
    • C23C14/28—Vacuum evaporation by wave energy or particle radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36—Removing material
    • B23K26/362—Laser etching
    • B23K26/364—Laser etching for making a groove or trench, e.g. for scribing a break initiation groove
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

  • This invention pertains to a method for lowering the ablation threshold of a laser- ablated material by having on a surface of the laser-ablated material a structuring which affects the reflection of a laser beam.
  • the invention further pertains to a laser-ablatable target material the ablation threshold of which is considerably lower than normal and which facilitates efficient industrial manufacture of several different surfaces using laser technology.
  • Such lasers for cold- work include picosecond lasers and femtosecond lasers.
  • the cold- work range refers to pulse lengths of 100 picoseconds or less.
  • picosecond lasers differ from femtosecond lasers in the repetition frequency; the repetition frequencies of latest commercial picosecond lasers are 1 to 4 MHz, whereas the repetition frequencies of femtosecond lasers are in the kilohertz range.
  • the cold ablation enables vaporization of material such that no heat transfers are directed to the material to be vaporized (ablated), i.e. only the pulse energy is directed solely to the material ablated by each pulse.
  • Competing with the fully fiber based diode pumped semiconductor laser is the lamp pumped laser source in which the laser beam is first conducted into the fiber and thence further to the work spot. According to the information available to the applicant on the priority date of the present application these fiber based laser systems are at the moment the only way to bring about laser ablation based production on an industrial scale.
  • Scanning widths this small also contribute to the fact that the use of present-day laser equipment in surface treatment applications for large and wide objects is industrially unfeasible or technically impossible to implement.
  • pulse laser equipment designed for cold ablation known at the priority date of the present application will yield an effective power of about 20 W in ablation.
  • the laser pulse repetition frequency achieved with planar scanners may be limited to only a 4-MHz chopping frequency. As the frequency becomes higher, more and more pulses will overlap in the material to be vaporized. Thus the surface of the material will melt locally deeper and the next laser beam will be absorbed in the vaporizing plasma.
  • the scanners according to the prior art will cause a significant part of the pulses of the laser beam being directed uncontrollably onto the wall structures of the laser apparatus, and also into the ablated material in the form of plasma, having the net effect that the quality of the surface to be produced using the ablated matter will suffer as will also the production rate and, furthermore, the radiation flux hitting the target will not be uniform enough, which may affect the structure of the plasma produced, which thus may, upon hitting the surface to be coated, produce a surface of uneven quality.
  • the problems become worse as the size of the plasma plume gets bigger. If it is possible to increase the scanning width, the power produced by the laser will be distributed across a larger area.
  • Target materials to be vaporized will reflect part of the laser radiation back, whereby energy of the laser radiation will not be used for the ablation of the target material. Therefore, ablation thresholds of materials (the amount of energy needed for "lighting up” the matter, i.e. to start the generation of plasma) remain high, and the power needed for ablation remains high as well. Some materials cannot be ablated at all, and for some materials ablation is so weak that the plasma produced is of poor quality which leads to surfaces of low quality or modest material machining rates and cutting depths. A major part of the laser power is wasted or degrades the quality of the plasma by hitting it or, in the worst case, damages the laser apparatus when reflected.
  • present-day target materials used in laser ablation have such surface structures that they reflect a significant part of laser radiation hitting the surface part of the target material, for example.
  • Target materials having a metal surface are especially problematic, but the problem applies equally to metal oxides and other materials, too. Since a significant portion of the radiation is reflected away, the amount of energy needed for ablation, the ablation threshold, becomes higher. This reduces the ablation rate and, hence, the machining speed as well as the production rate for plasma depositions. As laser apparatus have limited powers, some of the materials cannot be vaporized at all.
  • This invention pertains to a method for lowering the ablation threshold of a laser- ablated material by having on a surface of the laser-ablated material a structuring which reduces the reflection of a laser beam.
  • This invention further pertains to a laser-ablatable target material having on a surface of the laser-ablated material a structuring which reduces the reflection of a laser beam.
  • the present invention is based on a surprising notion that the ablation threshold of a target material (material to be vaporized) can be lowered by forming on a surface of the laser-ablated material a structuring which reduces the reflection of a laser beam.
  • the structuring may also be fabricated as part of the vaporization/machining process, meaning that the laser can be utilized for making a suitable structuring as an integrated part of production.
  • the ablation threshold can be further lowered by heating the material to be vaporized and, for example, applying a chemical treatment such as oxidization, nitridization or carburization to modify the surface of the material to be vaporized so that it better absorbs the laser beam.
  • the present invention is also based on the surprising notion that by doping the material to be vaporized with one or more substances the ablation threshold of the material to be vaporized (ablated) is dramatically lowered.
  • aluminum oxide by itself has an ablation threshold of over 6 ⁇ J/cm2. If it is doped with titanium oxide, the ablation threshold with the same laser parameters (1064 nm, 20 ps, 20 w) will become as low as 0.5 to 0.6 ⁇ J/cm2.
  • Another such compound is yttrium-stabilized zirconium oxide and yttrium aluminum oxide (YAG) which is easily vaporized as such, whereas pure aluminum oxide has a considerably higher vaporization threshold.
  • the invention shall not be limited to these compounds, the underlying principle being that a material hard to ablate can be made more readily ablatable with considerably lower pulse energies by doping a hard-to-ablate substance with an "impurity". Sometimes this "impurity", or dopant, may even be useful from the point of view of the final properties of the surface structure produced from plasma. Typically the dopant will not reduce/degrade, at least not significantly, the hardness, uniformity or surface roughness properties of the surface produced.
  • the present invention has industrial significance in that the laser power needed in vaporization and vaporization-based deposition and surface-treatment processes (cutting and engraving, lithography) will be considerably lower. This also facilitates efficient vaporization of several hard-to-vaporize materials, such as aluminum oxide, on an industrial scale.
  • the scanning width can be increased without the surface quality or the production rate or the cutting speed of the machined material requiring any significant increase in the laser power. Production will be energy-efficient and, thus, very environment-friendly.
  • the scanning width and laser pulse repetition frequency can be increased by using a turbine scanner instead of a mirror scanner.
  • Fig. 1 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 2 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 3 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 4 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 5 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 6 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 7 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 8 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 9 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 10 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 11 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 12 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 13 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 14 illustrates a structuring on an ablatable target material according to the invention
  • Fig. 15 illustrates a structuring on an ablatable target material according to the invention.
  • the structuring is produced on a surface of a lamella- like target material
  • Fig. 16 illustrates a feed module of a tape-like target material of 300 mm according to an example according to the invention
  • Fig. 17 illustrates a manner according to the invention of placing in parallel four modular feed modules for a tape-like 300-mm target material, facilitating the coating of targets having a width of 1200 mm, for instance,
  • Fig. 18 illustrates in more detail the structure of a tape feed apparatus for a target material according to the invention
  • Fig. 19 illustrates an embodiment of a turbine scanner
  • Fig. 20 illustrates an overlapping scan pattern produced with a turbine scanner and its deflected mirrors.
  • the invention pertains to a method for lowering the ablation threshold of a laser- ablatable material by having on a surface of the laser-ablatable material a structuring which reduces the reflection of a laser beam.
  • the material to be ablated will absorb a bigger portion of the laser beam's energy which in turn will lower the ablation threshold of the material.
  • Ablation of the material thus requires a lower power of the laser beam, boosting the production rate of the ablation itself.
  • This is industrially beneficial both in material deposition and machining applications.
  • the quality of the plasma produced is better and more easily controllable, the surfaces produced have a better quality and the machining result is better.
  • a surface may refer to a surface or a 3D material. No geometric or three-dimensional limitations are imposed here on a "surface". Thus, according to the invention, not only is it possible to coat 3D materials but also to create them.
  • atomic plasma also refers to a gas at least partly in an ionized state which may also include parts of an atom still containing electrons bonded to the nucleus through electrical forces. So, once-ionized neon, for example, could be considered atomic plasma. Naturally, also particle groups comprised of electrons and pure nuclei as such, separated from each other, are counted as plasma. Pure good plasma thus contains only gas, atomic plasma and/or plasma, but not solid fragments and/or particles, for instance.
  • the effective depth of the heat pulse from a laser pulse hitting the surface of a material varies considerably between laser systems. This affected area is called the heat affected zone (HAZ).
  • the HAZ is substantially determined by the power and duration of the laser pulse.
  • a nanosecond pulse laser system typically produces pulse energies of a few hundred mJ or more, whereas a picosecond laser system produces pulse energies of 1 to 10 ⁇ J. If the repetition frequency is the same, it is obvious that the HAZ of the pulse produced by the nanosecond laser system, with a power of over 1000 times higher, is significantly deeper than that of the picosecond pulse.
  • a significantly thinner ablated layer has a direct effect on the size of particles potentially coming loose from the surface, which is an advantage in so-called cold ablation methods.
  • Nano-sized particles usually will not cause major deposition damages, mainly holes in the coating when they hit the substrate.
  • fragments in the solid (also liquid, if present) phase are picked out by means of an electric and/or magnetic field. This can be achieved using a collecting electric field and, on the other hand, keeping the target electrically charged so that fragments moving with a lower electrical mobility can be directed away from the plasma in the plasma jet.
  • Magnetic filtering operates by deflecting the plasma jet so that the particles can be separated from the plasma.
  • the structuring according to the invention reduces reflection with any laser equipment.
  • the structuring which reduces reflection of the laser beam is especially advantageous when using pulse lasers and, furthermore, especially advantageous when using cold-work lasers such as a picosecond laser.
  • the power of the picosecond laser is typically at least 10 W, advantageously at least 20 W, and preferably at least 50 W. No upper limit is here imposed on the power of the laser apparatus.
  • the ablation threshold of a laser-ablatable material can be lowered e.g. in such a manner that the transverse diameter of an individual structure in the structuring on the material is 0.1 ⁇ m to 1 mm, advantageously 0.3 ⁇ m to 100 ⁇ m, and preferably 0.5 ⁇ m to 1.5 ⁇ m.
  • the transverse diameter of an individual structure on the surface of the material to be ablated is equal to or smaller than the measure of the wavelength of the laser light used in the ablation.
  • a typical wavelength used in picosecond lasers is 1064 nm, or about one micrometer.
  • a molten layer of 1 to 2 ⁇ m is typically formed on the surface of the material ablated.
  • the diameter of an individual structure in the direction of depth may be from 0.1 ⁇ m to 1 mm, advantageously 0.3 ⁇ m to 100 ⁇ m, but absolutely preferably 0.5 ⁇ m to 3 ⁇ m especially in cold ablation applications.
  • Choice of an optimal structuring also depends on the quality required of the coating.
  • the diameter of an individual structure in the direction of depth is advantageously not more than twice the wavelength of the laser light used.
  • the laser-ablatable material is heated in connection with the ablation. This lowers the ablation threshold of the material to be ablated.
  • An especially advantageous temperature for the material is achieved when it is heated towards the temperature of the conductivity threshold of the material. This is the characteristic temperature of each material in which the electrical conductivity of the material increases dramatically. The advantageous temperature in question always comes before the melting point of the material to be ablated.
  • the material to be ablated is composed of a metal, metal alloy, glass, stone, ceramic, synthetic polymer, semisynthetic polymer, paper, cardboard, natural polymer, composite material, or inorganic or organic monomer or oligomer.
  • the material to be ablated is advantageously intended for producing surfaces.
  • Surfaces may be produced using one or more target materials and one or more laser beams. It is also possible to produce surface structures not known before.
  • the invention does not limit the materials to be ablated or materials to be coated. They can be freely chosen among all possible materials.
  • the deposited surface is produced as follows: reactive material is brought into a plasma plume made of ablated material, which reactive material reacts with the ablated material in the plasma plume and the compound(s) thus generated form the surface on the substrate (material to be coated).
  • the material to be ablated may also be a material to be machined.
  • the structuring may also be produced only on those particular spots which are to be machined.
  • the machining may comprise engraving or through-cutting, for example.
  • the material to be ablated is treated chemically or thermally so that its ablation threshold is lowered.
  • This can be achieved by mixing into the material to be ablated another material which lowers the ablation threshold, i.e. the material to be ablated is made a composite material all components of which are advantageously ablatable.
  • This can also be achieved by heating the target material so that the surface structure of the material is more easily broken in ablation. Involvement of a reactive gas will boost the effect.
  • suitable composite materials include andalusite, moissanite, kyanite, sillimanite, and mullite. Furthermore, the ablation thresholds of some materials are dramatically lowered when even a small amount of yttrium, for instance, is added in them.
  • Such compounds include yttrium-stabilized zirconium oxide or yttrium- stabilized aluminum oxide (YAG), indium tin oxide (ITO), and aluminum titanium oxide (ATO).
  • composite material composed of a combination of one or more simple (or monolithic) materials in which the individual constituents retain their distinct identities.
  • a composite material has different properties than its constituent materials; the term composite often implies enhanced physical properties as the main technological objective is to produce materials having superior properties in comparison with the constituent materials of the composite.
  • a composite material also has a heterogeneous structure formed of the phases of the two or more components of the composite.
  • the phases may be continuous phases or one or more of the phases may be a dispersed phase within a continuous matrix.”
  • the surface layer of the material to be ablated is treated chemically or thermally so that the ablation threshold of the material is lowered. This can be achieved e.g. by oxidizing, nitridizing or carburizing the surface layer of the material to be ablated so that the surface of the material will reflect less laser radiation. As said, this can also be achieved by heating the target material so that he surface structure of the material is more easily broken in ablation. Involvement of a reactive gas will boost the effect.
  • the material to be ablated is in the form of a lamella (a sheet-like target).
  • a lamella a sheet-like target.
  • Such lamella structures can be placed in a vaporizing chamber (where ablation takes place) in such a manner that a new lamella structure is always pushed into the place of the previous, already-used lamella structure.
  • the lamella sheets are advantageously just so thick that it is technically possible to feed them. This method of feeding the material is very suitable for thin, structured ceramic plates of aluminum oxide, for example. Let it be noted that the fabrication of large targets is usually laborious and expensive.
  • the material to be ablated is in the form of a film or tape.
  • the thickness of such a film/tape material to be ablated is from 1 ⁇ m to 5 mm, advantageously 20 ⁇ m to 1 mm, and preferably 50 ⁇ m to 200 ⁇ m.
  • the target material is a structured version, in accordance with the invention, of a prior-art rotating target material (US 6,372,103).
  • the structuring of the material to be ablated may have been done already in connection with the manufacture of the target material, by means of compression rolls or other lithographic techniques, for example.
  • the structuring of the surface may also be done using a laser. In that case the structuring may be integrated in the ablation process, as a preliminary stage thereto.
  • the structuring may be done either so as to cover the whole surface of the target or just at desired spots, in an embodiment of the invention only at those spots that are to be cut/engraved.
  • Lowered ablation thresholds enable laser ablation also in normal atmospheric pressure or in a gaseous atmosphere such as nitrogen, oxygen, carbon dioxide or hydrocarbon.
  • the target material and, particularly, its surface can be treated chemically with a laser so that the lowering of the ablation threshold can be integrated in the coating or machining process.
  • the invention can be implemented in a vacuum in which the pressure is 10 "1 to 10 "12 arm. So, in a method according to the invention, a surface of high quality and strong enough for the application in question, having the desired optical properties (colored or transparent), can be achieved in such a manner that a substrate is coated using laser ablation in roughly a vacuum or even in a gaseous atmosphere of the normal atmospheric pressure.
  • the material is ablated by a laser beam in such a manner that material is vaporized substantially all the time at a spot which has not been significantly ablated before.
  • the material preform is usually in the form of a thick bar or sheet.
  • a zoom focusing lens must be used or the material preform must be moved toward the laser beam as the material preform gets consumed. Even an attempt to implement this is already extremely difficult and expensive, if at all possible in a manner sufficiently reliable, and even then the quality varies greatly, whereby precise control is almost impossible, the manufacture of a thick preform is expensive and so on.
  • the scanners according to the prior art As the laser beam control technique is limited due to, among other things, the scanners according to the prior art, this cannot be done without problems, especially when increasing the pulse frequency of the laser apparatus. If one attempts to increase the pulse frequency to 4 MHz or higher, the scanners according to the prior art will cause a significant part of the pulses of the laser beam being directed uncontrollably onto the wall structures of the laser apparatus, and also into the ablated material in the form of plasma, having the net effect that the quality of the surface to be produced will suffer as will also the production rate and, furthermore, the radiation flux hitting the target will not be uniform enough, which may affect the structure of the plasma, which thus may, upon hitting the surface to be coated, produce a surface of uneven quality.
  • the distance between the target and substrate will change at these pulses.
  • the pulses directed to the target hit spots on the target which have already been ablated, the pulses will remove different amounts of material so that particles of several microns will be ablated from the target. Such particles, when hitting the substrate, considerably degrade the quality of the surface produced and, therefore, the properties of the product.
  • Another problem in prior-art solutions is the scanning width.
  • Fig. 19 illustrates an embodiment of the turbine scanner.
  • Fig. 20 in turn illustrates an overlapping scan pattern produced with the turbine scanner and its deflected mirrors.
  • the scan patterns overlap only partially so that the quality of the plasma (and that of the machining) is excellent, avoiding the massive overlapping of pulses which occurs in conventional scanners especially at high repetition frequencies.
  • the turbine scanner solves power transmission problems associated with earlier planar mirror scanners in such a manner that target material can be vaporized at a pulse power high enough, producing plasma of a uniform and good quality and, therefore, surfaces and 3D structures of a good quality.
  • the turbine scanner itself facilitates scanning widths broader than before and, hence, the coating of larger areas by one and the same laser equipment. The machining speed is thus good and the quality of the surface produced has a uniform quality.
  • the turbine scanner thus enables an increase in the laser's repetition frequency (e.g. over 4 MHz) retaining the controllability of the beam. This results in a higher laser power with the various benefits associated with it.
  • the scanning width directed to the target is 1 mm to 800 mm, advantageously 100 mm to 400 mm, and preferably 150 mm to 300 mm.
  • the power of the laser is distributed across a larger area to be vaporized.
  • lowering the ablation threshold of the material is especially advantageous when using broad scanning widths. Lowering the ablation threshold also facilitates an efficient coating of a high quality of large objects at a reasonably low laser power such as 20 watts.
  • the invention also pertains to a laser- ablatable material target and/or target material a surface of which has a structuring which reduces the reflection of the laser beam.
  • the transverse diameter of an individual structure in the structuring is 0.1 ⁇ m to 1 mm, advantageously 0.3 ⁇ m to 100 ⁇ m, and preferably 0.5 ⁇ m to 1.5 ⁇ m.
  • the transverse diameter of an individual structure is advantageously equal to or smaller than the measure of the wavelength of the laser light used in the ablation.
  • the wavelength of picosecond lasers for instance, is 1064 nm.
  • the diameter in the direction of depth of an individual structure is 0.1 ⁇ m to 1 mm, advantageously 0.3 ⁇ m to 100 ⁇ m, and preferably 0.5 ⁇ m to 3 ⁇ m. Therefore, when using picosecond lasers, for example, the diameter in the direction of depth of an individual structure is advantageously not more than two times the measure of the wavelength of the laser light used.
  • the target material comprises surface formations that are arranged additionally to enhance transference of the plasma from the target, which plasma is released from the target from it from such an ensemble of surface formations that are in the area of the target that is being ablated away by a cold-work laser.
  • such formations comprise a narrowing target material region, arranged to narrow outwards from the target's surface.
  • the formations can be tilted and/or skewed.
  • the shape of the formation can be in one embodiment conical, but in another embodiment round.
  • the formations are ridge like, but according to other respective embodiment like pyramids or prisms or bumbs.
  • the material target may be such that the material ablated thereof is metal, metal alloy, glass, stone, ceramic, synthetic polymer, semisynthetic polymer, paper, cardboard, natural polymer, composite material, inorganic or organic monomer or oligomer.
  • Examples of some suitable composite materials include andalusite, moissanite, kyanite, sillimanite, and mullite. Furthermore, the ablation thresholds of some materials are dramatically lowered when even a small amount of yttrium, for instance, is added in them.
  • Such compounds include yttrium-stabilized zirconium oxide or yttrium-stabilized aluminum oxide (YAG), indium tin oxide (ITO) and aluminum titanium oxide (ATO), and element carbon.
  • the material target may be treated chemically such that its ablation threshold is lowered. In an embodiment, this may be achieved by doping the material with another material which lowers the ablation threshold, as described above.
  • the surface layer of the material to be ablated is treated chemically so that the ablation threshold of the material is lowered.
  • One way is to treat the ablatable material chemically such that the capacity of the surface to absorb laser radiation is enhanced. This can be achieved e.g. by oxidizing, nitridizing or carburizing the surface layer of the material to be ablated. When the material has once "lit up", less energy is needed to ablate the material, i.e.
  • the lighting-up may require a pulse energy of 5 ⁇ J, for example, but the ablation itself will progress with a pulse energy of 0.6 ⁇ J.
  • a rough analogy would be the lighting-up of a fire in the fire-place, for instance.
  • the structuring of the material to be ablated may have been done already in connection with the manufacture of the target material, by means of compression rolls or other lithographic techniques, for example.
  • the structuring of the surface may also have been done using a laser.
  • the structuring may be integrated in the ablation process, as a preliminary stage thereto.
  • the structuring may have been done either so as to cover the whole surface of the target or just at desired spots, in an embodiment of the invention only at those spots that are to be cut/engraved.
  • a target material according to the invention is in the form of a lamella, thread, or shaped thread. This may be e.g. a little thicker, sheet-like piece of the material to be ablated. Thickness of the sheet may vary from micrometers to several centimeters. It is preferable to use lamella structures as thin as possible.
  • the lamellae may be arranged in the vaporizing unit such that when one lamella is technically used up, the next one is automatically placed so as to be vaporized/machined. Apart from serving as a source of material for deposition plasma the lamella may also serve as an uncut/unengraved preform of the product.
  • target materials are valuable and advantageously only the virginal surface part is used of the target surface, it is industrially advantageous to use targets as thin as possible.
  • Tape-form target materials are naturally considerably cheaper than current target materials (big, solid targets) and also better available because of the easier and cost-efficient manufacturing methods.
  • the target material is in the form of film or tape.
  • the target material according to the invention and the method of using it for lowering the ablation threshold of the material are not limited solely to lamella and/or tape/film feed, but apply to all target materials used in laser ablation.
  • Thickness of the tape/film may be e.g. 1 ⁇ m to 5 mm, advantageously 20 ⁇ m to 1 mm, and preferably 50 ⁇ m to 200 ⁇ m.
  • Figs. 17 and 18 illustrate feeding arrangements of a tape-like target material according to the invention.
  • the film/foil is then e.g. in the reel form, as shown in Fig. 17.
  • the tape/foil is moved e.g. sideways to such an extent that a completely new track can be formed. This can be continued until the foil/film is completely used up in the direction of the breadth.
  • the method according to the invention can be used to produce, very cost- effectively from an industrial standpoint (low laser power and in many applications lower volumes than in the prior art or even in normal atmosphere or gas phase), surfaces and/or 3D materials having various functions.
  • surfaces include e.g.
  • Yet other products fabricated in accordance with the invention may include surfaces and 3D materials resistant to corrosive chemical compounds, semiconductor materials, LED materials, pigment materials and surfaces made thereof which change color according to the viewing angle, already-mentioned parts of laser equipment and diode pumps, such as beam expanders and the light bar in the diode pump, jewel materials, surfaces of medical products and medical products in 3D shapes, self-cleaning surfaces, various products for the construction industry such as already-mentioned pollution- and/or moisture-resistant and, if necessary, self- cleaning stone and ceramic materials (coated stone products and products onto which a stone surface has been deposited), dyed stone products, e.g. marble dyed green in accordance with an embodiment of the invention or self-cleaning sandstone.
  • surfaces and 3D materials resistant to corrosive chemical compounds, semiconductor materials, LED materials, pigment materials and surfaces made thereof which change color according to the viewing angle such as beam expanders and the light bar in the diode pump, jewel materials, surfaces of medical products and medical products in 3D shapes,
  • Further products fabricated according to the invention may include anti-reflective (AR) surfaces e.g. in various lens and monitor shielding solutions, coatings protective against UV radiation, and UV-active surfaces used in the purification of water, solutions or air. So, the thickness of the surfaces produced can be controlled. Therefore, the thickness of a diamond or carbon nitride surface formed according to the invention may be 1 nm to 3000 irai, for example. In addition, the diamond surface can be made extremely even. So, the evenness of a diamond surface (and oxide surfaces) may be on the order of ⁇ 25 nm, advantageously it is ⁇ 10 nm, and in some demanding, low-friction applications it can be adjusted to ⁇ 0.2 nm.
  • AR anti-reflective
  • the diamond surface according to the invention not only prevents the underlying surfaces from being mechanically worn but also prevents them from being subjected to chemical reactions.
  • the diamond surface prevents metal oxidation, for instance, and thus the destruction of their decorative or other function.
  • the diamond surface protects the underlying surfaces against acids and alkalis.
  • the diamond surface according to the invention not only prevents the underlying surfaces from being mechanically worn but also prevents them from being subjected to chemical reactions.
  • the diamond surface prevents metal oxidation, for instance, and thus the destruction of their decorative or other function.
  • the diamond surface protects the underlying surfaces against acids and alkalis. In certain applications decorative metal surfaces are desired.
  • Some especially decorative metals or metal alloys utilizable as targets according to the invention include gold, silver, chrome, platinum, tantalum, titanium, copper, zinc, aluminum, iron, steel, zinc black, ruthenium black, ruthenium, cobalt, vanadium, titanium nitride, titanium aluminum nitride, titanium carbon nitride, zirconium nitride, chrome nitride, titanium silicon carbide, and chrome carbide.
  • these compounds can be used to achieve other properties, too, such as wear-resistive surfaces or surfaces protective against oxidation or other chemical reactions.
  • metal alloys worth mentioning here include metal oxides, nitrides, halides and carbides, but the metal alloys are not limited to these.
  • Different oxide surfaces fabricated according to the invention include aluminum oxide, titanium oxide, chrome oxide, zirconium oxide, tin oxide, tantalum oxide, various doped versions of these, such as titanium aluminum oxide, yttrium- stabilized zirconium aluminum oxides, ITO, ATO, and the combinations of these in composites with each other or metals, diamond, carbides or nitrides, for instance. These materials, too, can be manufactured according to the invention also from metals using a reactive gaseous atmosphere.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Toxicology (AREA)
  • Health & Medical Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Laser Beam Processing (AREA)
  • Physical Vapour Deposition (AREA)
  • Inorganic Insulating Materials (AREA)
  • Control And Other Processes For Unpacking Of Materials (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)

Abstract

L'invention concerne un procédé destiné à abaisser le seuil d'ablation d'un matériau soumis à une ablation laser par utilisation, sur une surface du matériau soumis à une ablation laser, d'une structure réduisant la réflexion d'un faisceau laser. Le seuil d'ablation peut également être abaissé par chauffage du matériau et par modification chimique du matériau ou de sa surface, même légèrement. L'invention facilite la mise en oeuvre industrielle de l'usinage d'une pluralité de surfaces et de matériaux divers. Cette invention se rapporte en outre aux matériaux cibles à soumettre à une ablation.
PCT/FI2007/000094 2006-04-12 2007-04-12 Procédé destiné à ajuster un seuil d'ablation Ceased WO2007116124A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20060358 2006-04-12
FI20060358A FI20060358L (fi) 2006-04-12 2006-04-12 Menetelmä ablaatiokynnyksen säätämiseksi

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WO2007116124A1 true WO2007116124A1 (fr) 2007-10-18

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009125057A1 (fr) * 2008-04-09 2009-10-15 Metso Paper, Inc. Procédé de travail de la surface d'un élément de machine à fabriquer des toiles fibreuses et élément de machine pour une machine à fabriquer des toiles fibreuses

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986000553A1 (fr) * 1984-07-02 1986-01-30 American Telephone & Telegraph Company Formation d'elements dans un materiau optique
GB2233334A (en) * 1989-06-29 1991-01-09 Exitech Ltd Surface treatment of polymer materials by the action of pulses of UV radiation
US5569399A (en) * 1995-01-20 1996-10-29 General Electric Company Lasing medium surface modification
WO2003047807A1 (fr) * 2001-12-04 2003-06-12 General Atomics Procede et appareil permettant d'accelerer la vitesse d'enlevement de matiere lors d'un usinage au laser
WO2005104253A1 (fr) * 2004-04-01 2005-11-03 Cree, Inc. Modelisation au laser de dispositifs electroluminescents et dispositifs electroluminescents ainsi obtenus
US20060000814A1 (en) * 2004-06-30 2006-01-05 Bo Gu Laser-based method and system for processing targeted surface material and article produced thereby

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986000553A1 (fr) * 1984-07-02 1986-01-30 American Telephone & Telegraph Company Formation d'elements dans un materiau optique
GB2233334A (en) * 1989-06-29 1991-01-09 Exitech Ltd Surface treatment of polymer materials by the action of pulses of UV radiation
US5569399A (en) * 1995-01-20 1996-10-29 General Electric Company Lasing medium surface modification
WO2003047807A1 (fr) * 2001-12-04 2003-06-12 General Atomics Procede et appareil permettant d'accelerer la vitesse d'enlevement de matiere lors d'un usinage au laser
WO2005104253A1 (fr) * 2004-04-01 2005-11-03 Cree, Inc. Modelisation au laser de dispositifs electroluminescents et dispositifs electroluminescents ainsi obtenus
US20060000814A1 (en) * 2004-06-30 2006-01-05 Bo Gu Laser-based method and system for processing targeted surface material and article produced thereby

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009125057A1 (fr) * 2008-04-09 2009-10-15 Metso Paper, Inc. Procédé de travail de la surface d'un élément de machine à fabriquer des toiles fibreuses et élément de machine pour une machine à fabriquer des toiles fibreuses

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FI20060358A0 (fi) 2006-04-12
FI20060358L (fi) 2007-10-13

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