This invention relates generally to manufacturing methods and devices for laser machining single or multilayer materials. The field of this invention also extends to the manufacture of components relating to food and pharmaceutical, medical, in vitro diagnostic, and microfluidic devices and packaging.
The present invention relates generally to manufacturing methods and devices for laser machining materials. Typically laser processing of devices has been in the areas of laser cutting, surface machining, surface treatment, and laser welding. Laser cutting typically involves cutting entirely through a substrate; surface machining techniques selectively remove parts of a substrate; physical surface treatment involves melting or etching the surface, whereas chemical surface treatment typically operates below the ablation threshold to modify the surface properties; and laser welding typically involves selectively melting the interfacial material between two surfaces, and can be performed by either direct surface exposure, or through the use of transmission or reverse conduction welding for joining internal surfaces. Scanned beam systems are known for all methods and lithographic systems have been used for structuring and surface modification depending on the energy density, material properties, resolution, and throughput required.
Applications for the laser processing of multilayer materials typically involve the removal of outer layers of material, such as the stripping of insulation off wires or exposing electrodes on printed circuit boards, or welding via transmission and reverse conduction methods.
Transmission laser welding operates by one material being transparent to and the other material being an absorber of the irradiated laser wavelength. This allows the laser beam to selectively heat between the two materials producing localised welding when the heat rises above the glass transition temperature. For integration into the production environment, the main limitations are processing times, and limitation of compatible materials and number of layers that can be processed.
Reverse conduction welding operates in a similar manner to transmission layer welding except that the heat is generated by laser absorption at a backplane. The polymer films clamped above the absorbing layer conduct the heat from its surface and locally melt. Due to uniform heat conduction within the polymers which limits spatial resolution, the technique is only suitable for thin films and relatively large structures.
More recently specific laser absorbers, such as Clearweld®, have been used for bonding. In practice this material is difficult to apply to mass production of micromachined substrates and produces a slightly opaque weld that can reduce the appeal of a product or interfere with the operation, for example, sensor response, of some devices.
Lasers have also been used for micromachining substrate surfaces. These techniques usually employ ultraviolet (UV) lasers, typically excimer lasers, which can produce fine anisotropically etched structures down to one micron. Unfortunately such systems are expensive and relatively slow to process material. More recently, focus has been on the use of shorter wavelength UV lasers that can machine channels down to 100 μm, depending on the material thickness. Unfortunately such systems provide a large heat-affected zone that limits fine structures, such as those required for microfluidic geometries. In a similar manner, infrared (IR) YAG and CO2 lasers have been demonstrated for microfluidic channel fabrication for large structures only (in the order of hundreds of microns).
The challenge in incorporating such technologies into manufacturing processes relates to the time required for the laser to complete its machining process as well as the quality morphology of the resulting cut or machined surface.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.
The invention provides methods for laser structuring of single and multilayered materials. The invention includes apparatus, methods and products.
The method, apparatus and devices of the present invention have many advantages, including in various embodiments, for example:
In a first aspect of the invention, there is provided a method for manufacturing at least part of a device comprising a substrate wherein at least one laser is used to alter a portion of the substrate during the manufacturing process. Certain embodiments provide such a method for manufacturing at least part of a multilayered device comprising use of at least one laser to alter at least one layer of said part during the manufacturing process.
In a second aspect of the invention, there is provided, an apparatus for manufacturing at least part of a device comprising a substrate, the apparatus comprising at least one laser source to produce a laser beam to alter at least one portion of the substrate during the manufacturing process. Certain embodiments provide such an apparatus for manufacturing at least part of a multilayered device comprising at least one laser source to produce a laser beam to alter at least one layer of said part during the manufacturing process.
In a third aspect of the invention, there is provided a part of a device manufactured according to the process or using the apparatus of the present invention.
In a fourth aspect of the invention, there is provided a device manufactured according to the process or using the apparatus of the present invention.
Some preferred embodiments are particularly adapted to manufacture of specialist devices, such as microfluidic devices.
Any suitable laser with any suitable characteristics may be used in the method or apparatus of the present invention. For example, in some embodiments, a variety of wavelengths are utilized and in others, a plurality of laser beams.
In embodiments which comprise a plurality of laser beams, the laser beams may for example improve the formed structure and/or simplify the manufacturing process. In some embodiments, the plurality of laser beams use at least one part of the same alignment system. The plurality of laser beams may interact with each other or be used in ways which enhance the overall processing. Thus, for example, the plurality of laser beams may operate at least partially simultaneously or they may operate optionally at least partially concurrently or at least partially intermittently. The plurality of laser beams may also be operated with one or more timing characteristics.
In some embodiments, the laser beam energy is increased which may for example enable faster processing. Thus in some embodiments, the increased laser beam energy enables alteration of the dominant processing mechanism, which is optionally one or more of thermal melt, plasma formation, ablation by bond cleavage and subsequent volume expansion, and multi-photon bond dissociation.
Embodiments with a plurality of laser beams may also enable simplified manufacturing processing, for example by reducing cost, improving alignment, increased speed of processing, and optionally for example when a plurality of beams use parts of the same alignment system.
In some embodiments, a first laser beam and a second laser beam work in conjunction with one another. In one such embodiment, a first laser beam forms a melt and a second laser beam removes material, optionally by laser induced shockwaves and optionally by a pulsed laser beam. In another embodiment, a first laser beam increases bond or lattice energy to an excited state and a second laser beam removes material, optionally with an increased energy density. In a further embodiment, a first laser beam removes material and a second laser beam alters surface morphology, optionally by inducing surface reflow for reshaping, debris minimisation, crystallinity changes, and/or surface chemistry alteration. In some embodiments a first laser beam having a first wavelength is used to target a first portion of substrate and a second laser beam having a second wavelength is used to target a second portion of substrate. In some of these embodiments applicable to multilayered devices, the first laser targets a first layer and the second laser targets a second layer. In other embodiments, the first laser beam targets a particular chemical bond in the substrate and a second laser beam having a second wavelength is used to target a different chemical bond in the substrate.
In some embodiments which comprise a plurality of laser beams, the beams may be combined prior to falling incident on a portion of substrate or a layer. Combination of the beams may be by any suitable method, for example, by using an optical element, such as a mirror or lens. In some embodiments, the plurality of laser beams originally arise from the same source.
The material to be lasered may be of any suitable form. Some preferred embodiments comprise the use of an additive in a layer to alter the effect of a laser beam on that or another layer. Thus, for example, the additive may affect and optionally improve radiation absorption at the laser's wavelength. Equally, however, it may increase transmission of a laser beam through the substrate and consequently indirectly affect the substrate or layer below. Some embodiments comprise the use of a portion of substrate (which may for example, be a layer) with an absorption and/or reflection characteristic to influence the effect of the laser. The characteristic may be of any suitable form, for example, it may allow selective machining of an absorbing portion of substrate (which may for example, be a layer).
Other suitable aspects of the material to be lasered may be provided, altered, or optimised. For example, the material may comprise a thermally conductive portion (which may for example, be a layer) for improved structure formation.
Various thermal techniques may also be used as part of the present invention. For example, heat may be reduced or guided to provide improved structure geometry or reduce the effect of the machining process on the surrounding materials and structures.
Various masking techniques may also be used as part of the present invention. Thus, one embodiment comprises the use of a masking component between the laser source and a portion of substrate (such as a layer) to limit or alter exposure to the laser beam on an area of the substrate or layer. The mask or masking component may take any suitable form, for example, in applications relating to multi-layer devices, the masking component may itself be a portion of the substrate or a layer.
The present invention may also be used to increase throughput, for example by providing parallel processing. In some such embodiments a masking component may contribute to alignment of parts during manufacture. In some embodiments a masking component provides greater spatial resolution. The masking component may perform one or more functions, such as for example: conducting heat away from an area on a portion of substrate, such as a layer, (b) protecting a surface from debris, and/or (c) supporting one or more structures during processing.
The present invention may be further optimised with the use of an optical component to alter or focus the laser beam. The optical component may take any suitable form, for example it may comprise one or more lenses, prisms or other refractive, diffractive or reflective elements. In some embodiments, the optical component simplifies alignment of parts during processing. The optical component may perform one or more functions such as for example, altering one or more of the frequency, intensity, direction, duration or timing of the laser beam.
In some embodiments of the present invention, a portion of substrate such as a layer may be removed during or after the manufacturing process. The use of such a removable portion of substrate or layer, in some situations referred to as a sacrificial portion or sacrificial layer, can add further benefits to the present invention. In some embodiments which comprise such a portion of substrate or layer which is removed, the removed portion may perform one or more of the following functions: protect a surface from debris, thermal conduction, support cut out or free standing structures, focus or mask a beam, allow a secondary machining process to occur.
The substrate material and/or layers the subject of the laser processing and/or manufacturing of the present invention may be of any suitable type. Thus, for example, they may comprise one or more of polymer, metal, metal oxide, metal foil, paper, nitrocellulose, glass, silicone, photo-resist, ceramic, wood or fabric.
The process flow of a method and apparatus according to the present invention may be arranged in any suitable manner. In some embodiments, the process utilizes an at least semi-continuous web while in others, the process is not web-based.
The method and apparatus of the present invention is also particularly suited to the use of additional non-laser processing steps which may occur before, during or after a laser step. Any suitable non-laser step may be used in conjunction with the present invention. Thus, in some embodiments, a non-laser process step comprises one or more of injection molding, micromilling, die cutting, hot foil stamping, stamping, embossing, thermoforming, print-head deposition, photolithography, coating, curing. In some embodiments, a non-laser processing step comprises a pre-treatment process, which may for example reduce the heat affected zone from the laser machining process. A pre-treatment process according to the present invention may comprise any suitable steps, thus for example, it may comprise one or more of: providing cooling or heat sinking to parts of the material, or modifying the material's surface or bulk properties to alter the thermal conductivity or absorption characteristics.
In some embodiments, there is further provided a post-treatment process which may for example optionally structure, cure, surface treat, coat or render one or more parts.
The application of thermal energy, or heat is one example of a non-laser processing step which may have particular benefits. In one embodiment, one or more of the area of the substrate or layer to be laser treated, the local area on the substrate or a tool may be heated to improve material flow around a tool. Any suitable tool may be used, for example, it may be an embossing tool. In one embodiment, a laser beam is scanned over an area to be embossed. Such scanning may occur at any suitable timed, for example prior to, during or after embossing.
In some embodiments, a structure is formed by selectively applying a laser to a defined area of a substrate or layer to thereby weaken it. Such a process step may be used to make a wide variety of useful structures, for example, burst valves, tearing guides, perforations, meshes, etc. Some embodiments utilise the laser to alter the barrier properties of a portion of substrate or layer by selective application of the laser. This may occur by any suitable means, for example a series or network of perforations through a portion of substrate or layer.
A laser treatment step according to the present invention may occur at any suitable stage. For example, a component part of a device to be manufactured in accordance with the invention may be laser treated prior to or after assembly of the device. In some embodiments, assembly of a multilayered device comprises laser treatment. This may occur for example where assembly comprises a laser-treatment bonding step which may for example comprise laser assisted bonding of layers.
Precision alignment is a very important part of certain embodiments of the present invention. In some embodiments, the method or apparatus comprises the use of one or more alignment marks, notches, grooves, or edge guides for alignment. Some embodiments also comprise the use of a control system. Any suitable control system may be used, for example it may comprise one or more of: mechanical sensor feedback, optical sensor feedback, part translation and/or laser scanning adjustment.
Throughout this specification (including any claims which follow), unless the context requires otherwise, the word ‘comprise’, and variations such as ‘comprises’ and ‘comprising’, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
It is convenient to describe the invention herein in relation to particularly preferred embodiments relating to food and pharmaceutical, medical, in vitro diagnostic, and microfluidic devices and packaging. However, the invention is applicable to a wide range of situations and products and it is to be appreciated that other constructions and arrangements are also considered as falling within the scope of the invention. Various modifications, alterations, variations and or additions to the construction and arrangements described herein are also considered as falling within the ambit and scope of the present invention.
As used herein, the term “fluid” refers to either gas or liquid phase materials. As used herein, the term “microfluidic” refers to fluid handling, manipulation, or processing carried out in structures with at least one dimension less than one millimetre. As used herein, the term “beam” or “ray” refers to more than one photon travelling in a substantially similar direction. Laser machining techniques used in the present invention include, but are not limited to, scanned beam and lithographic systems. Laser and material interactions used in the present invention may be of any suitable type, and may for example include photo-thermal, photo-chemical processes or combinations of the two.
The laser beam incident on the substrate or material may be from a single laser or a plurality of lasers. Where multiple laser beams are combined to machine the work-piece, the beams may operate simultaneously or with different timing characteristics. For example laser beams may operate at the same or different wavelengths irradiating the same area either, alternatively, concurrently, or simultaneously at different switching frequencies.
Various improvements are made possible by combining multiple beams, such as for example, increasing beam energy density to provide faster processing. In addition, a combination of multiple beams increases beam energy density which enables alteration of the dominant processing mechanisms, such as thermal melt, plasma formation, ablation by bond cleavage and subsequent volume expansion, and multi-photon bond dissociation. Furthermore, a combination of multiple beams may simplify manufacturing implementation by reducing alignment issues and by increasing the speed of processing when the beams are delivered using the same alignment mechanism. Some examples include: alignment mechanisms may be in the form of the laser beams using separate optical paths and a common alignment controller, or the beams may share a common optical path, such as where the laser beam guiding stage is common to both beams. An example of this would be where galvo mirror scanners or x-y driven output optics are common to both laser beams. Such improvements in manufacturing are particularly important for micro-structuring to avoid the use of additional costly alignment systems, which would also introduce a further tolerance requirement associated with the error in beam placement between the multiple alignment systems. A further advantage of using multiple beams is that it enables the use of multiple processing methodologies which mean faster processing and improved structure formation. This may be done in various ways, for example:
In one embodiment, multiple laser beams are combined prior to irradiating the material; as shown in
The laser machined structures may be fabricated on discrete parts or onto reels of continuous material.
An example of a production line for the fabrication of continuos parts, or onto a web, is illustrated in
Structures produced according to the present invention may be cut, rendered or divided into smaller parts.
In one embodiment of the invention, laser machined parts are bonded to other components, which may or may not be a continuous substrate, and may or may not be planar, and may be made of single or multiple components.
In another embodiment, the laser machining processes may be combined with other structuring processes; such as injection molding, micromilling, die cutting, hot foil stamping, stamping, embossing, thermoforming, print-head deposition, photolithography, coating, curing and other structuring methods.
The present invention may also be combined with other processes to facilitate the laser machining process or improve the performance of laser machined devices. For example the present invention may be combined with one or more pre-treatment processes to reduce the heat affected zone from the laser machining process. Such pre-treatment may include providing cooling or heat sinking to parts of the material, or modifying the material's surface or bulk properties to alter the thermal conductivity or absorption characteristics. Post-treatment processes may also be used to structure, cure, surface treat, coat or render the parts. For example PCT/AU2007/000061 describes a combined laser embossing process that enables more rapid replication of embossed features than normal and hot embossing. By pretreating the local area to be embossed with lasers, the local material is altered, which allows (a) lowering of the softening point (as is especially the case with orientated films), preheating of the exposed area, (b) material reflow and (c) in some cases, ablation from the embossed area.
After laser processing, and before stamping, the area of the film to be treated, the local area on the substrate or the tool may be heated to improve the material flow around the tool. The laser beam may expose the entire substrate surface or just the area to be embossed, as illustrated in
The combination of other processes with laser process may occur either simultaneously or in any order. In some embodiments, it occurs simultaneously. For example, in one embodiment an embossed material is laser machined during the embossing processes. Whilst the embossing tool is pressed to the surface of the material, the laser irradiates the reverse side of the material to cause localised reflow around the tool to improve the speed of embossing, and or the replication of the structure from the embossing process. Processing in this manner also helps to relieve some of the induced stresses in the material around the reflowed area, which is critical in microstructure formation where the induced stresses can cause structure deformation when the tool is removed. A material transparent to the lasing wavelength is typically used to support the embossed material during such a process. In an alternative arrangement, the laser absorbing layer may be a thin layer located thermally close to the embossing area, and the substrate may be transparent, so that upon laser irradiation the embossed area is heated by the absorbing layer.
The use of alignment marks, notches, grooves, and or edge guides are common approaches used for alignment in many manufacturing systems. In one preferred embodiment of the process, the present invention uses control systems to facilitate alignment and provide quality control. Parameters in the control system include, but are not limited to, mechanical and/or optical sensor feedback with part translation or laser scanning adjustment for improved alignment.
In certain preferred embodiments of the invention, one or more materials may include the use of specific absorber additives to improve the material's absorption at the laser's wavelength.
In certain preferred embodiments of the invention the device or component to be laser processed is made of multi-layered materials. One or more layers of the material may have different heat conduction characteristics allowing improved structure formation. For example,
In certain preferred embodiments of the invention the device or component to be laser processed is made of multi-layered materials. One or more of the layers of the material may have different absorption characteristics allowing selective machining of the absorbing layers, as illustrated in
In certain preferred embodiments of the invention the device or component to be laser processed is made of multi-layered materials. One or more of the layers of the material may have different absorption and or reflection characteristics allowing the selective machining of absorbing layers. As illustrated in
In another preferred embodiment of the invention the multi-layered device or component to be laser processed is machined prior to assembly. For example
In another preferred embodiment of the invention the device or component to be laser processed is machined after assembly into a multi-layered component or device. For example,
In another embodiment of the invention the device or component may incorporate layers that act as masking components to guide the radiation onto specific locations. This approach allows the use of larger laser beams to create smaller structures than normally achievable with the full beam exposure. The use of larger beam lasers and laser curtains may also be used to increase the throughput of the machining process by enabling parallel machining from the same laser beam. Such a method also offers the advantage of decreasing the alignment requirements for the laser system by using a mask to provide tight tolerances. Such a masking system may also provide greater spatial resolution in a similar manner to traditional lithographic systems. Furthermore, such a masking system may also provide manufacturing advantages if the mask is part of the manufactured component by simplifying alignment between features on a single device and between each manufactured part. Furthermore the masking material may be used to (a) improve the thermal heat affected zone on the sample by conducting some of the heat away from the structured area, (b) protect the substrates surface from debris, and/or (c) support the machined structures during processing.
In another embodiment of the invention the device or component may incorporate layers that use optical components, such as lenses, prisms or other refractive or diffractive features, to focus and/or redirect the radiation onto specific locations. This method also offers the advantage of decreasing the alignment requirements for the laser system by using the optical components to provide the tight tolerances required. Such optical components may provide greater spatial resolution by focussing the radiation. In addition, such optical components may also provide manufacturing advantages by having the optical components as a part of the manufactured component and thus simplifying alignment between features on a single device and between each manufactured part.
In some embodiments of the invention, the mutilayer parts have layers removed after the laser machining process, or after parts of the manufacturing process. Extra layers may be used during the machining process for various reasons, for example to protect the surface from debris, act as a thermal conductor to minimise the heat affected zone on the machined substrate, and support cut out, or free standing, structures as outline in US PCT/AU2007/000061. The layers may also be used during the machining process to focus or mask a beam, provide heat conduction, or allow a secondary machining process to occur.
The example in
In one embodiment of the invention the selectively machined layer is used to weaken the surrounding structure to form a burst valve. These burst valves can be made by partially machining through a layer of a multilayer device or entirely machining through one layer and leaving a thin adjacent layer that may rupture under pressure. A layer can be selectively machined by using an adjacent transparent, heat conductive or reflective layer.
In one embodiment of the invention the selectively machined layer is used to weaken the surrounding structure to form a tearing guide. For example,
In one embodiment of the invention the selectively machined layer is used to perforate selected layers of a multi-layer material to alter the barrier properties of the device. This technique provides the added advantage of allowing spatial control of the barrier properties on a multi-layer device such as packaging using the same materials and fabrication process for the entire package. In the following example, shown in
Number | Date | Country | Kind |
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2006903098 | Jun 2006 | AU | national |
PCT/IB2006/003311 | Nov 2006 | IB | international |
PCT/AU2007/000012 | Jan 2007 | AU | national |
PCT/AU2007/000061 | Jan 2007 | AU | national |
PCT/AU2007/000062 | Jan 2007 | AU | national |
PCT/AU2007/000435 | Apr 2007 | AU | national |
This application claims priority from U.S. provisional patent application No. 60/811,437, filed on 7 Jun. 2006 the entire contents of which are incorporated herein by reference. This application also claims priority from Australian provisional patent application AU 2006903098 filed on 7 Jun. 2006, the entire contents of which are incorporated herein by reference. This application also claims priority from International (PCT) application PCT/IB2006/003311, filed on 22 Nov. 2006, the entire contents of which are incorporated herein by reference. This application also claims priority from International (PCT) application PCT/AU2007/000012, filed on 11 Jan. 2007, the entire contents of which are incorporated herein by reference. This application also claims priority from International (PCT) application PCT/AU2007/000061, filed on 24 Jan. 2007, the entire contents of which are incorporated herein by reference. This application also claims priority from International (PCT) application PCT/AU2007/000062, filed on 24 Jan. 2007, the entire contents of which are incorporated herein by reference. This application also claims priority from International (PCT) application PCT/AU2007/000435, filed on 10 Apr. 2007, the entire contents of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/AU2007/000802 | 6/7/2007 | WO | 00 | 3/12/2009 |
Number | Date | Country | |
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60811437 | Jun 2006 | US |