METHOD AND SYSTEM FOR MACHINING MICROTECHNOLOGY WORKPIECES

Description

Field of invention

[0001] The invention relates to the general field of microtechnology and in particular the machining of parts by engraving with a laser. The invention relates more particularly to a method and a system for machining small parts of hard materials using a very short pulse laser, more particularly a femtosecond laser.

[0002] The machining system finds particular application in the watchmaking industry, particularly for the production of watch parts. Applications can also be found in the fields of fluidics (nozzles) and medicine (bearings, insulators). State of the art

[0003] The use of parts made from very hard materials such as diamond, sapphire, corundum or ceramics is known in various fields such as medical applications or watchmaking.

[0004] Traditional machining techniques are mostly limited to machining or shaping techniques using abrasives or chemical or plasma treatment techniques.

[0005] For example, machining rounded holes in sapphire parts for watchmaking is achieved by multiple passes of an abrasive wire and this process is carried out mainly manually which leads to a long and expensive process. Also, the precision of the shape of the openings will depend on the experience of the operator and is therefore subject to variations which for some applications may be unacceptable.

[0006] Document FR2995413A1 describes a process for manufacturing small hard parts by laser cutting a wafer of crystalline material. Subject of the invention

[0007] The invention relates to a method for laser machining a large number of small parts made of hard materials. In particular, the method makes it possible to produce surfaces of revolution and openings in a plurality of parts brought and arranged on a substrate which can be any support.

[0008] The system and method enable extremely fast and reliable laser machining of concave or convex surfaces and holes in small workpieces and in hard materials such as diamond, corundum and ceramics.

[0009] The system and method of the invention allow femtosecond laser machining machines, which are extremely expensive machines, to be used to their maximum capacity. This is key in the field of manufacturing watch jewels but also precision medical parts such as those used for example in endoscopes. A particular application is the production of curved surfaces and holes and openings in Al 2 O 3 watch parts.

[0010] In a first aspect, the invention relates to equipment for machining microtechnology hard parts, comprising a machining machine comprising a system for loading / unloading hard part supports and at least one laser system comprising at least one laser for machining said hard parts and a system for controlling said laser. Said machining machine defines a horizontal plane XY and a vertical axis Z orthogonal to the horizontal plane XY.

[0011] Each support comprises, at least on one side, a surface arranged to fix a plurality of hard parts thereto.

[0012] The equipment comprises a device for measuring the XYZ position of each hard part of at least one set of hard parts relative to a reference frame and means for recording said XYZ positions arranged to cooperate with the laser control system.

[0013] The laser control system comprises a system for positioning said laser arranged to, before machining each hard part, move and position the laser relative to said hard part to be machined according to the recorded XYZ position of said hard part so as to be able to machine said hard part.

[0014] The present invention also relates to a method for machining hard microtechnology parts. The method comprises the following steps (AF): A: providing the machining equipment as described above and providing a plurality of microtechnology hard parts to be machined; B: providing at least one part support and fixing said plurality of said hard parts on said part support; C: inserting at least one of said part supports into said machining machine; D: measuring the XYZ position of each of said hard parts of at least one set of hard parts fixed on the part support relative to said reference mark, by means of said measuring device and recording the measured XYZ positions by means of said recording means; E: carrying out pre-programmed machining steps of said hard parts of at least said set by said at least one laser, said laser being, before the machining of each hard part of said set, moved and positioned relative to said hard part to be machined as a function of the XY Z position of said hard part measured and recorded in step D;F: release at least one of said hard parts from its support.;

[0015] Such machining equipment and process allow, among other things, the machining of holes in hard microtechnology parts and ensure that the holes are perfectly positioned, for example perfectly centered in relation to their circumference. The laser is of the femtosecond type. An advantage of the machine is that it is suitable for machining at least 5,000 parts in less than 10,000 seconds. Descriptions of the figures

[0016] The invention will be better understood by reading the detailed description of an exemplary embodiment made with reference to the appended figures, among which: There Figure 1a And 1b represent steps of the machining method according to the invention; The Figure 2 represents a hole made in a hard part; The Figure 3represents a machining equipment comprising a machining machine comprising a part loading / unloading system, as well as a hard part testing system; The Figure 4 represents the arrangement of a plurality of hard parts on a support, typically a semiconductor wafer; The Figure 5 represents a support, typically a semiconductor wafer, comprising two sets of hard parts of different types; The Figure 6 represents an arrangement of hard parts before their laser machining according to the method of the invention; The Figure 7 represents a part of a machining equipment including a laser and a vision system; The Figure 8 represents an arrangement of parts placed on a support before their laser machining according to the method of the invention; The Figure 9 represents a vision system for measuring the 3D position of a set of hard parts; The Figure 10represents a system for optical measurements of hard parts comprising the vision system of the Figure 9 . The optical measuring system can be positioned outside the machining machine shown in the Figure 7 ; There Figure 11 represents the machining of two hard parts by two different laser beams; The Figure 12 represents a part loading system; The Figure 13 represents a suction system of the parts loading system of the Figure 10 ; There Figure 14 represents a part-laying system of the part-loading system of the Figure 10 ; There Figure 15 represents the laser machining of the camber of a watch part; The Figure 16 represents the laser machining of a hollow in a watch part. Description of embodiments of the invention

[0017] The invention relates to a method for machining small parts 1 made of hard materials. In particular, the method makes it possible to produce surfaces of revolution and / or openings in a plurality 10, 12 of hard parts 1 brought and arranged on a substrate which can be any type of support 100.

[0018] Although a preferred application of the invention relates to the field of watchmaking, it is not limited to this field and can be applied to any field which benefits from small hard parts which have openings and / or machined surfaces such as curved surfaces or surfaces defined by a polygon in at least one section of said hard part 1.

[0019] For example, the dimensions of rubies used in watch mechanisms are very small and it is very difficult to machine them precisely and at low cost and high speed. The outer diameter of these parts is typically between 0.5 and 3 mm, the thickness is between 0.05 mm and 1 mm.

[0020] It is therefore very difficult to load and unload stones very quickly into a machining machine in order to ensure the rate allowed by machining. Standard methods use loading by vibrating bowls or by vision-guided flexible feeding systems which load the stones directly into clamping positions, which allows perfect positioning of the stone before machining. These methods are very difficult to develop to achieve high levels of reliability and autonomy. In addition, they are incapable of achieving very high loading / unloading rates (we are talking about rates between 0.5 seconds and 1 second per part).

[0021] On the other hand, machining the surface and / or internal hole by femtosecond laser is very fast, and machining can be done in approximately 0.5 to 1.5 seconds depending on the dimensions of the openings to be made. Typical opening diameters are between 0.05 mm and 2 mm.

[0022] In a first aspect, the invention relates to a machining equipment 1000 for microtechnology hard parts 1. The machining equipment 1000 comprises a machining machine 200, comprising a loading / unloading system 220 for supports 100 for hard parts 1, and at least one laser system comprising at least one laser 204 for machining said hard parts 1 and a system for controlling said laser 204. Said machine 200 defines a horizontal plane XY and a vertical axis Z orthogonal to the horizontal plane XY.

[0023] Each support 100 comprises, at least on one side, a surface arranged to fix a plurality of hard parts 1 thereto. Preferably, said support is a pierced support with openings provided at each position intended to position a hard part 1.

[0024] The machining equipment 1000 comprises a device for measuring the XYZ position of each hard part 1 of at least one set of hard parts 1 relative to a reference frame and means for recording said XYZ positions arranged to cooperate with the laser control system 204.

[0025] The machining equipment 1000 includes a positioning table 208 arranged to accommodate a workpiece support 100 as illustrated in Figures 4, 5, 6 . There Figure 6 illustrates a laying of hard parts 1 made of silicon with a SiO 2 coating In the example of the Figure 6 , the hard parts of a set of hard parts, illustrated in black in the Figure 6, are each placed at a positional accuracy in XY, relative to a reference mark on their support 100, of approximately 20 µm. This accuracy is not precise enough to carry out precise machining. This is why the machining equipment includes a precise position measuring system, in XYZ, of the hard parts, and this at a precision which is preferably better than 2 µm, preferably better than 1 µm.

[0026] The laser control system comprises a system for positioning said laser 204 arranged to, before the machining of each hard part 1, move and position the laser 204 relative to said hard part 1 to be machined according to the recorded XYZ position of said hard part 1, so as to be able to machine said hard part 1.

[0027] In one embodiment, the equipment is arranged to control the machining of holes in each hard part 1 and ensure that the holes are perfectly positioned, for example precisely centered relative to their circumference.

[0028] Said at least one laser 204 is a femtosecond laser. A femtosecond laser is a particular type of laser which produces ultra-short pulses whose duration is of the order of a few femtoseconds to a few hundred femtoseconds, i.e. of the order of magnitude of the period of a visible electromagnetic wave.

[0029] Advantageously, the laser source delivers light at wavelengths of 1030 nm, 515 nm or 343 nm.

[0030] Typical pulse durations are preferably between 200 fs and 10 ps.

[0031] The maximum energy per pulse is advantageously close to 2 mJ.

[0032] For hard parts, such as those made of Al 2 O 3 , the laser power is typically 20 W, but will be adapted depending on the material of the hard parts1.

[0033] Advantageously, the focusing and 3D movements of the beam are carried out by an optical block, for example an optical block which may comprise a system for adapting the shape of the laser beam and an orientation of 3, 4 or 5 axes in space. For example, the focusing of the laser beam may be adapted during the machining operation of the hard parts 1.

[0034] Advantageously, the position measuring device may comprise a vision system 206. Such a measuring system, not illustrated in the Figures, may make it possible to determine a geometric parameter of the hard parts 1, such as their 2D or 3D dimensions.

[0035] In one embodiment, illustrated in Figure 7, the position measuring device is integrated into the machining machine 200. The device for measuring the XYZ position of the hard parts 1 comprises an optical system 206 which is preferably fixed to said laser 204, as illustrated in the Figure 7 . There figure 9illustrates an exemplary embodiment of such an optical system 206 comprising a detector 206a, a display system 206b adapted to form images in a horizontal plane XY and an illumination system 206c. The XYZ position measuring system comprises a system for determining the vertical position Z of the hard parts 1. Advantageously, such a vertical position measuring system is an optical system 206d comprising a dynamic focusing system in the vertical direction Z. It is understood that the 2D display system can be arranged to make 2D measurements according to different predetermined vertical positions. For example, different 2D images can be taken for different Z positions. The system can also be adapted to ensure 2D images for a certain vertical position.For example, the vision system can be moved in the vertical direction so as to visualize a predetermined surface, for example the top face 1a or the back face 1b of the parts. This makes it possible to increase the accuracy of the 3D XYZ measurement of the hard parts 1.

[0036] In an advantageous variant, the reference mark is at least one alignment mark produced on a surface of said support 100 of hard parts 1. The reference mark may for example consist of one or more alignment patterns, for example cross-shaped patterns.

[0037] In one variant, the reference mark is at least one alignment mark made on a frame of a reception and translation system for said support 100.

[0038] Advantageously, the XYZ position measuring device is arranged to perform a measurement with an accuracy of less than 20 µm, preferably 10 µm, more preferably 5 µm, and preferably less than 2 µm, in the 3 axes X, Y, Z.

[0039] In one embodiment, the machining equipment 1000 comprises means for processing the recorded XYZ positions of the hard parts 1 of at least two sets of hard parts 1, said sets possibly having hard parts 1 in common, the processing means being arranged to obtain a recording reconstituting the XYZ position of the hard parts 1 of said at least 2 sets combined, and preferably of all the hard parts 1 fixed on said support 100.

[0040] In variants, the XYZ position measuring system can be arranged with the machining machine but can be separated from the machining part. An in-line measurement allows for a minimum time between the measurement of the positions of the stones and the use of these measurements for machining.

[0041] In variants, said set of hard parts 1 consists of hard parts 1 of the same type or of a different type.

[0042] In one embodiment, the support 100 is arranged to fix at least two assemblies containing hard parts 1 of different types. Figure 5 for example illustrates a support 100 on which two types of sets of parts 10, 12 are fixed before their machining.

[0043] In one embodiment, the loading / unloading system 220 comprises at least one movable cassette 220a, 220b, 220c, 220d, 220e, 220f, 220g, 220h, 220i for each containing at least one of said carriers 100. In a preferred embodiment, each of the movable cassettes 220a, 220b, 220c, 220d, 220e, 220f, 220g, 220h, 220i can contain at least 20 carriers 100.

[0044] Said mobile cassettes 220a-220i preferably comprise frames associated with a transfer system arranged to translate the supports from the loading / unloading system 220 to the machining machine 200, as schematically illustrated in the Figure 1a .

[0045] In one embodiment, not illustrated in the Figures, the machining machine 200 comprises a system for releasing, after their machining, at least a portion of the hard parts 1 from their support 100.

[0046] In one embodiment, said positioning system comprises a 5-axis optical system arranged to cooperate with the control system of said laser 204, to be able to orient the laser beam 210 emitted in the 3 dimensions XYZ.

[0047] In a particularly advantageous manner, the machining machine 200 comprises a machining program for machining a predetermined number of said plurality of hard parts 1. In variants, for example, the machining program may make it possible to machine two sets 10, 12 of hard parts by two different lasers of the machining machine 200 or may make it possible to machine two sets 10, 12 of parts by two different operating modes of the laser. These different operating modes may consist of the use of different energies or powers, and / or by an adjustment of the numerical aperture of the laser beam.

[0048] In an alternative embodiment, the machining machine 200 comprises a machining program for machining at least a portion of the hard parts 1 according to different machining steps. For example, each part can be processed by making a hole, followed by an operation of processing an edge or a circumference of the hard part 1.

[0049] Preferably, the support 100 is a wafer made of semiconductor material, ceramic material, metal alloy or glass. In order to better hold the hard parts 1, said support 100 is preferably a pierced support, advantageously with openings 100a provided at the location of the installation of the hard parts 1, as illustrated in the Figures 1b , 11 , 15, 16 .

[0050] Advantageously, each support 100 can be arranged to receive more than 100, preferably more than 500, preferably more than 1000, preferably more than 5000 hard parts 1. In a practical embodiment, the support 100 can receive more than 8000 hard parts 1.

[0051] Preferably, the 200 machine is suitable for machining at least 5000 parts in less than 10000 seconds.

[0052] Advantageously, as illustrated in Figure 3 , the machining equipment 1000 may comprise a measuring system 300 for measuring the XYZ position of the hard parts 1. This system 300 may also be adapted for measuring the 2D and / or 3D geometry of the hard parts 1.

[0053] It is understood that said vision system 206 can be adapted to visualize and determine geometries of the machined hard parts, for example during or after the machining cycle.

[0054] In one embodiment, the inventive machining machine 200 may include at least two lasers that produce non-parallel beams. For example, a first femtosecond laser may be adapted to make apertures and another laser may be used to produce a beam that is not parallel to the beam of the first laser.

[0055] Advantageously, the machining machine of the invention can comprise at least one multi-beam optic, suitable for carrying out simultaneous machining of several parts at the same time.

[0056] The invention also relates to a method for machining microtechnical parts made of hard material comprising the different steps (AF) consisting of: A: providing the machining equipment as described above and providing a plurality of microtechnology hard parts 1 to be machined; B: providing at least one part support 100 and fixing said plurality of said hard parts 1 on said part support 100; C: inserting at least one of said part supports 100 into said machining machine 200; D: measuring the XYZ position of each of said hard parts 1 of at least one set of hard parts 1 fixed on the part support 100 relative to said reference mark, by means of said measuring device and recording the measured XYZ positions by means of said recording means;E: performing pre-programmed machining steps of said hard parts 1 of at least said set by said at least one laser 204, said laser 204 being, before the machining of each hard part 1 of said set, moved and positioned relative to said hard part 1 to be machined as a function of the XY Z position of said hard part 1 measured and recorded in step D; F: releasing at least one of said hard parts 1 from its support 100.;

[0057] Once the parts 1 are loaded and referenced on the XYZ table of the machining machine 200, the machining rate of the parts 1 arranged on a support 100 is dictated by the machining time, for example by the machining time of the hole - typically 0.5 to 1.5 sec - plus the time to move the table from one stone 1 to the next. The machining time is typically 0.3 to 1 second depending on the size and the distance between each stone. For stones with an outside diameter of 0.9 mm, more than 8,000 stones can be arranged on a round support with a diameter of 150 mm. Loading and unloading the supports is extremely easy, and even if it is not fast, the time is divided by the number of stones per support 100. An automatic support loading system allows the machining machine to operate completely autonomously for very long periods, despite a part machining cycle time that is typically around 1 second.

[0058] Preferably, the measurement of the XYZ position of each workpiece 1 is done by a vision system 206. The vision system can be fixed on an internal surface of the machining machine, but preferably, the measurement of the XYZ position of each workpiece is done by an optical system which is fixed to said laser 204, as illustrated in Figure 7 .

[0059] Alternatively, the XYZ position of the parts is measured on a test system 300 which can determine at least the XY position of the hard parts relative to a reference frame of the part support. It is then sufficient to position this part support precisely on the positioning table 208 of the machine in order to know the precise position of the parts relative to the system which includes the machining laser 204.

[0060] Of course, a second series of XYZ measurements can be made additionally in the machining machine 200, after the support and the hard parts have been placed, at least the XY position of the hard parts 1 of which is known relative to a reference frame of the support. This makes it possible to increase the precision of the XYZ measurement relative to the system which includes the laser 204.

[0061] In a particularly advantageous manner, the measurement of the position of the hard parts 1, according to step D of the XYZ position measurement, comprises the successive measurements of the position of the parts of at least 2 sets relative to the same reference frame, said sets possibly having hard parts 1 in common, said successive measurements possibly partially overlapping, and the processing of said successive measurements by the processing means of the machining equipment to obtain a recording reconstituting the XYZ position of the hard parts 1 of said at least 2 sets combined, and preferably of all the hard parts 1 fixed on said support 100.

[0062] In a typical example, the vision system proceeds by taking pictures of each of the hard parts individually. In an advantageous example, in order to reconstruct the XYZ position of all the hard parts 1, the vision system proceeds by taking successive pictures of 10 to 15 hard parts, as illustrated in the Figure 8 .

[0063] The set of hard parts 1 can consist of hard parts 1 of the same type or of different types. Depending on the type of parts to be machined, the machining process can be adapted.

[0064] In a variant of the method, during step E, the positioning of the laser 204, relative to said hard parts 1, is done by a movement in an XY plane or in the XYZ space of said laser 204.

[0065] In another variant, during step E, the positioning of the laser 204 relative to said hard parts 1 is done by a movement of said part support 100.

[0066] It is also possible that, during step E, the positioning of the laser 204 is done by a movement of said laser 204 and also of said part support 100. These two movements do not necessarily have to be simultaneous.

[0067] In one embodiment, step D of measuring the position of the hard parts 1 is carried out successively for all the hard parts 1 just before their machining.

[0068] In one embodiment, step B of fixing the hard parts 1 is carried out by means of a parts loader 400 cooperating with the loading / unloading system 220.

[0069] In one variant, at least one step of cleaning the parts 1 is carried out between two machining cycles of the hard parts 1.

[0070] In one embodiment, the machining step E comprises at least the production of an opening 1c in at least one of said plurality of hard parts 1.

[0071] The material of said hard part 1 is, in one embodiment of the invention, chosen from: Al 2 O 3 , Sapphire, SiO 2 , Ceramic, Silicon Carbide, Silicon (Si), Glass, Quartz Glass, Diamond, Silicon Nitride, Quartz Glass (Fused Silica), Hard Metal.

[0072] The hard metal can be chosen from: titanium, stainless steel, tungsten, tantalum.

[0073] Ceramics can be made of ZrO 2 for example.

[0074] It is understood that said hard parts may be composite parts and may comprise at least two materials.

[0075] The method is preferably used for parts made of corundum (Al 2 O 3 ) or its derivatives such as sapphire.

[0076] In one embodiment of the invention, the materials of the hard parts 1 have a hardness on the Vickers scale between 1600-2000HV.

[0077] The supports 100 can be of any shape, typically rectangular, square or circular. The support can be a wafer, commonly called a wafer in English, made of semiconductor material, metal alloy, ceramic material or other material. Preferably, the support 100 is a transparent glass wafer, for example made of borosilicate glass. By using drilled supports with openings provided at each position intended to position a hard part 1, it is possible to facilitate the machining of the parts as well as to release them. Indeed, during the machining of the parts, illustrated in Figure 1b(step E) having an opening under each hard part makes it easy to pass through the adhesive film 120 which will be pierced, forming an opening 120a, and the material of the hard part 1 as well as that of the adhesive film 120 is evacuated through the opening 100a of the support 100 which is located under the hard part 1. This evacuation can be done by suction or by a pressurization system.

[0078] Preferably, step B of fixing hard parts 1 is implemented by a method chosen from temporary bonding, the use of friction forces, suction, creation of a vacuum, electrostatic forces, surface forces, mechanical tools, gels.

[0079] In alternative embodiments, the hard parts 1 may be arranged and temporarily fixed on an at least partially adherent layer 120, preferably a double-sided adherent layer.

[0080] In variants, the parts may be arranged and temporarily secured to a semi-adherent or adhesive layer such as a double-sided adhesive tape, for example a polymer film 120, which is secured to said support 100. Certain types of adhesive films used in microtechnology make it possible to provide adhesive strength without the need for glues. These films are commonly referred to as “blue tapes” and are known to those skilled in the art of microtechnology.

[0081] Some supports provide adhesion force through another mechanism, for example: magnetic effects and forces; electrostatic effects and forces; suction; friction forces; gas pressure; freezing of a water film

[0082] However, it is possible to temporarily fix the parts with temporary adhesives soluble in water or various solvents. Alternatively, temporary adhesives can also be applied that change their state through heat treatment or ultraviolet (UV) or infrared (IR) radiation.

[0083] Advantageously, the hard parts 1 can be placed on the supports 100 by a system 400 for placing hard parts 1 as illustrated in the Figures 10 , 11,12 . In such a placement system 400 the hard parts 1 are first placed on a hopper 222, illustrated in detail in the Figure 12 . This is done with a typical accuracy of ±20 µm. The hard parts 1 are then sucked up by a gripper 404, shown in detail in Figure 11. After the hopper 222 has been moved aside, preferably by sliding or lateral rotation, a support 100 is put in place of the hopper 222. Then, a pressure system 406 presses the gripper 404 against the support 100, preferably against an adhesive layer 120 fixed on the support 100.

[0084] Advantageously, the laser system 200 uses optics delivering more than one laser beam 210, 212, typically 2, 4, 9, 16 or more beams. This allows the simultaneous machining of several hard parts 1 at the same time. The Figure 9 illustrates the machining of a pair of hard parts 1 simultaneously by two laser beams 210, 212.

[0085] The company Pulsar Photonics for example, whose reference is found under the website https: / / www.pulsar-photonics.de / , offers a multi beam scanner solution for laser multibeam processing. Such a system comprises at least one beam scanner based on a galvano system. A selectable beam splitting with a multibeam module generates a fixed beam arrangement in the working plane of the scanning system.

[0086] This approach allows to multiply the speed of the process in the production of periodic structures.

[0087] Using a diffractive beam splitter, the power of the laser system can be divided into up to 100 partial beams and more. Typical beam distributions can be, without limitation: 2x2, 4x4, 8x8, where nxm or n and m are different numbers. It is understood that the laser beams can be different, for example they can have a different focal length.

[0088] With a suitable optical element, it is possible to create almost any arrangement, ensuring high homogeneity and overall efficiency.

[0089] By combining a multi-beam system with at least one galvanometric scanner, it is possible to generate a large number of treatment points in the treatment plan, which are moved simultaneously over the hard part 1 by said scanner.

[0090] The use of a multi-beam system allows efficient parallel production of identical structures in a single step.

[0091] It is thus possible to overcome the power limitations, essentially of physical origin, of many "ultra short pulse" processes and thus considerably increase the efficiency of the processes.

[0092] Areas of application are laser drilling, parallel processing of several components or general parallelization of laser processes.

[0093] The release of the hard parts 1, fixed by an adherent layer 120 to the support 100, can be done in various ways, for example by solvents or via heat treatment or UV exposure. Exposure to radiation can, for example, cause the release of gas at the bonding interfaces. The release can also be done by exposure to heat or flashes of infrared radiation. Said UV and / or infrared radiation can be carried out by pulsed power sources.

[0094] In variants, the step E of releasing the parts can be done in various ways: by applying vibration and / or shocks; by mechanical scraping; by using a pick and place arm or robot; by liquid and / or ultrasonic means; by blowing with air or other gas.

[0095] Preferably, the laser beam 210 emits in the infrared with a wavelength between 800 nm and 1100 nm, ideally 1030 nm, or in the green with a wavelength between 500 nm and 540 nm, ideally 515 nm, or in the blue with a wavelength between 400 nm and 480 nm or in the ultraviolet with a wavelength less than 400 nm, ideally 343 nm.

[0096] Advantageously, the 204 laser is a femtosecond laser which can be a laser emitting a UV, green or infrared beam. A 343 nm UV femtosecond laser and a 515 nm green femtosecond laser can achieve, on hard parts for example made of Al 2 O 3 , a roughness of less than 50 nm. In the case of an IR laser emitting a beam with a wavelength of 1030 nm, a typical roughness is 100 nm or better.

[0097] Femtosecond laser machining enables very precise machining accuracies, typically smaller than ±1 µm. Surface roughness in cutting mode can reach roughnesses of 50nm or less.

[0098] It is also understood that the machining equipment 1000 may be adapted to perform a first machining cycle and that the hard parts 1 are finished by another process such as a mechanical or chemical process or by plasma (DRIE). For example, drilled hard parts 1 may be treated inside or outside the machining machine 200 in order to clean them or for a plasma smoothing treatment performed on all the parts on a support 100, preferably a silicon wafer. It is also understood that in one embodiment the machining machine 200 may comprise means for depositing a coating on the parts before or after their machining.

[0099] In one embodiment the machine is suitable for machining at least 5000 parts in less than 10000 seconds.

[0100] In an advantageous embodiment, all of the parts 1 may undergo a first machining step which may be a surface preparation step performed by said femtosecond pulse laser. In a variant, all 10 of the parts 1 may undergo a cleaning and / or layer deposition step.

[0101] Depositing a layer before machining with the femtosecond laser allows for better delineation of the machining area. This layer can be removed after the machining process.

[0102] It is understood that the machining conditions can be adapted according to the location (i.e. drawer) of a cassette system of the machine of the invention. Thus, a first drawer can comprise a support with parts in which a hole is to be machined and another drawer can comprise another wafer with parts whose surface is to be corrected or on which a predetermined shape is to be executed.

[0103] In one embodiment, the media in a drawer of a cassette system 220 may undergo multiple machining cycles. For example, during a first cycle all of the parts are machined to have a hole and during a second loading of the wafers into the machine, all of the wafers may be re-machined through the machine to enlarge the hole and / or machine an edge of the parts.

[0104] In one embodiment, during at least a second machining cycle, at least one other type of laser may be used. This laser may be a second and another femtosecond laser.

[0105] Depending on the application, it is understood that the parts 10 do not necessarily have to be arranged in a homogeneous manner on their support 100. For example, the hard parts 1 can be arranged in a disc-shaped or rectangular arrangement.

[0106] In one embodiment, the workpieces can be fixed on both sides of a support, for example by temporary gluing. A double-sided arrangement (not shown in the Figures) makes it possible to increase the machining speed by the machining machine of the invention by a factor of 2.

[0107] It is understood that the position measuring system may be associated with a dimension and shape measuring system for each part. This measuring system may be adapted to perform dimension measurements of the parts during machining operations.

[0108] It is understood that a measuring system can be used to track the dimensions of machined parts and to adapt the machining parameters of the laser machine to enable autonomous and more precise production. Example of application and configuration of a machining system according to the invention

[0109] The following example shows an application case with watch jewels on wafers with a diameter of 150 mm. For jewels 1 with a diameter of 0.9 mm, we can put about 8,800 jewels 1 on a support 100 which is preferably a wafer and achieve machining rates of about 1 second, i.e. between 8 and 10 times lower than what could be obtained with a conventional approach.

[0110] In a preferred configuration, the machining equipment 1000 comprises: a loading / unloading system 220 of at least 25 supports 100, typically a loading system 220 of at least 25 wafers 100; a measuring system 300 capable of very precisely measuring the XYZ position of each hard stone 1; a machining system 200 comprising a femtosecond laser.

[0111] In the example, 8800 stones can be aligned on a single support 100. The loading and unloading system 220 is a “cassette” type system comprising a plurality of drawers, each drawer being adapted to contain a single wafer.

[0112] The various operations can take the following times: laser machining per part: 0.5 to 0.6 sec; XY table referencing: 0.3 sec; charge and discharge per wafer 140: 120 sec; measurement times: 60 sec.

[0113] This indicates a machining and part measurement time typically below 2 seconds, more precisely 0.92 sec for the example described.

[0114] In the execution example, the 220 cassette system will therefore include a maximum of 25x8800 parts to be machined, i.e. a maximum of 220,000 parts.

[0115] The method and the machine 200 of the example make it possible to insert the support 100 under the femtosecond laser 204 and to machine all the hard parts 1 on a single wafer 100. When all the parts fixed on a wafer 100 are machined, the wafer 100 is unloaded towards a drawer of the casette 220 of the machine 200 and the machining of the hard parts 1 fixed on a second wafer is carried out and so on.

Claims

1. An apparatus for machining hard microtechnology workpieces (1), comprising a machining unit (200) comprising a system for loading / unloading (220) support members (100) for hard workpieces (1) and at least one laser system comprising at least one laser (204) for machining said hard workpieces (1) and a system for controlling said laser (204), said unit (200) defining a horizontal plane X-Y and a vertical axis Z orthogonal to the horizontal plane X-Y, the material of said hard workpieces (1) being selected from materials having a hardness on the Vickers scale between 1600 HV and 2000 HV, or selected from: Al2O3, Sapphire, SiO2, Ceramic, Silicon Carbide, Silicon (Si), ZrO2, Glass, Quartz Glass, Diamond, a hard metal selected from titanium, stainless steel, tungsten, or tantalum, each support member (100) comprising, at least on one side, a surface arranged so that a plurality of hard workpieces can be attached thereto, each support member (100) being arranged to provide an adherent force, characterised in that - the laser (204) is a femtosecond laser, - the apparatus comprises a device for measuring the X-Y-Z position of each hard workpiece (1) of at least one set of hard workpieces (1) with respect to a reference mark and means for recording said X-Y-Z positions, which means are arranged to cooperate with the control system of the laser (204), - said control system of the laser comprises a system for positioning said laser (204), which system is arranged, before each hard workpiece (1) is machined, to move and position the laser with respect to said hard workpiece (1) depending on the recorded X-Y-Z position of said hard workpiece (1), such that said hard workpiece (1) can be machined.

2. The machining apparatus according to Claim 1, characterised in that the adherent surface is a surface of an adherent film.

3. The machining apparatus according to Claim 1 or 2, characterised in that the position measuring device comprises a vision system (206).

4. The machining apparatus according to any one of Claims 1 to 3, characterised in that the reference mark is at least one alignment mark and / or pattern made on a surface of said support member (100) for hard workpieces (1).

5. The machining apparatus according to any one of Claims 1 to 3, characterised in that the reference mark is at least one alignment mark and / or pattern made on a frame of a receiving system of said support member (100).

6. The machining apparatus according to any one of Claims 1 to 5, characterised in that the loading / unloading system (220) comprises at least one movable cassette (220a-i) to contain at least one of said support members (100).

7. The machining apparatus according to any one of Claims 1 to 6, characterised in that the support member has openings drilled therein, which are provided at each position which is intended to position a hard workpiece (1) .

8. A method for machining hard microtechnology workpieces (1) comprising the different steps (A-F) consisting of: A: providing the machining apparatus according to any one of Claims 1 to 7 and providing a plurality of hard microtechnology workpieces (1), the material of said hard workpieces being selected from materials having a hardness on the Vickers scale between 1600 HV and 2000 HV, or selected from: Al2O3, Sapphire, SiO2, Ceramic, Silicon Carbide, Silicon (Si), ZrO2, Glass, Quartz Glass, Diamond, a hard metal selected from titanium, stainless steel, tungsten, or tantalum; B: providing at least one workpiece support member (100) and attaching said plurality of said hard workpieces (1) to said workpiece support member; C: inserting at least one of said workpiece support members (100) into said machining unit (200); D: measuring, by means of said measuring device, the X-Y-Z position, with respect to said reference mark, of each of said hard workpieces (1) of at least one set of hard workpieces (1) attached to the workpiece support member (100), and recording the X-Y-Z positions measured by means of said recording means; E: performing pre-programmed steps of machining said hard workpieces (1) of at least said set by means of said at least one laser (204), said laser (204) being, before each hard workpiece (1) of said set is machined, moved and positioned with respect to said hard workpiece (1) depending on the X-Y-Z position of said hard workpiece (1), which position is measured and recorded in step D, F: releasing at least one of said hard workpieces (1) from its support member (100).

9. The method according to Claim 8, characterised in that the pre-programmed machining steps are done with the aid of a 5-axis system.

10. The method according to Claim 8 or 9, characterised in that step D comprises measuring the X-Y-Z position of the hard workpieces (1) on a test system (300) which is arranged to determine at least the X-Y position of the workpieces relative to a reference mark of the workpiece support member and the positioning of the workpiece support member precisely on a positioning table (208) of the machining unit.

11. The method according to any one of Claims 8 to 10, characterised in that the measuring of the position of the hard workpieces (1), according to step D, comprises the successive measurements of the position of the workpieces of at least 2 sets with respect to a same reference mark, wherein said sets can have hard workpieces (1) in common, wherein said successive measurements can partially overlap, and the processing of said successive measurements by the processing means of the machining apparatus to obtain a recording reconstituting the X-Y-Z position of the hard workpieces (1) of said at least 2 combined sets, and preferably of all of the hard workpieces (1) attached to said support member (100).

12. The method according to any one of Claims 8 to 11, characterised in that step D involving measuring the position of the hard workpieces (1) is carried out successively for all of the hard workpieces (1) just before their machining.

13. The method according to any one of Claims 8 to 12, characterised in that step B involving attaching the hard workpieces (1) is carried out by means of a workpiece loader (400) cooperating with the loading / unloading system (220).

14. The method according to any one of Claims 8 to 13, characterised in that the machining step E comprises at least making a hole (1c) in at least one of said plurality of hard workpieces (1).

15. The method according to any one of Claims 8 to 14, characterised in that step B involving attaching hard workpieces (1) is implemented by a method selected from temporary bonding, the use of friction forces, suction, creation of a vacuum, electrostatic forces, surface forces, mechanical tools, gels, and freezing of a film of water.