CH719655A2 - Process and equipment for corrective machining of microtechnical parts. - Google Patents

Abstract

The present invention relates to equipment for corrective machining of metal parts (10, 10') previously produced by a LIGA process, and comprising a machining machine (200) comprising force-free machining means for machining the metal parts ( 10, 10') and a force-free machining means control system. The equipment comprises a system for recording at least one target geometry and at least one predetermined reference X-Y-Z position specific to each metal part positioned on a support (2) relative to a reference mark. The corrective machining equipment makes it possible to determine and carry out a correction of the geometry to be made in relation to the target geometry. The invention also relates to a method for corrective machining of microtechnology metal parts (10, 10') previously produced by a LIGA process, the method comprising the different steps consisting of: A) providing metal parts on a support (2). (10, 10') previously produced by a LIGA process; B) equip yourself with corrective machining equipment and insert at least one support (2) into the machining machine (200); C) record a target geometry and at least one predetermined reference X-Y-Z position specific to each metal part (10, 10') positioned on the support (2) relative to a reference mark; D) recognize, in the reference frame, the 3D geometry and the positioning of the metal parts (10, 10') previously produced by the LIGA process, and determine a correction of the geometry to be made in relation to the target geometry and the position reference X-Y-Z recorded using the vision system (140) and the calculation unit (120); E) execute corrective machining steps of the metal parts (10, 10') by the force-free machining means (100), which are, before the corrective machining of each metal part (10, 10'), moved and positioned in the reference mark relative to the metal part (10, 10') to be corrected, in order to carry out the corrective machining according to the correction of the geometry determined in step D to obtain the target geometry; and F) release at least one of the metal parts (10, 10') from its support (2).

Description

Field of the invention

[0001] The invention relates to the general field of microtechnology and in particular the corrective machining of parts by force-free machining means. The invention relates more particularly to a method and equipment for corrective machining of small metal parts, previously produced by a LIGA process, using force-free machining means, such as a very short pulse laser.

[0002] Machining equipment finds particular application in the watchmaking industry, particularly for the production of watch parts. We can also cite applications in the fields of fluidics (nozzles) and medical (bearings, insulators) and connectors (test tips).

State of the art

[0003] The use of small parts made of metals is known in various fields such as medical applications or watchmaking.

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

[0005] Another technique consists of producing microtechnical parts using a LIGA (Lithographie Galvanoformung Abformung) process. Initially the technique was intended to operate with X-rays. The need to implement expensive equipment (synchrotron) makes this technique hardly compatible with mass production of microstructures which must have a low unit cost. This is why, on the basis of this LIGA process, similar processes have been developed but using resins photosensitive to ultraviolet (UV) radiation. Such a process is for example described in the publication by A.B. Frazier et al., entitled „Metallic Microstructures Fabricated Using Photosensitive Polyimide Electroplating Molds“, Journal of Microelectromechanical Systems, Vol. 2, Issue 2, 87-94, June 1993. This article describes a process for the manufacture of metallic structures by electrodeposition of metal in photosensitive resin molds based on polyimide.

[0006] LIGA technology makes it possible to produce geometries that are unrealizable using standard production processes. LIGA technology is an additive technique which has the advantage of being very inexpensive and which can be implemented quickly, which makes this process very competitive with traditional methods by material removal. The process is ideal for rapid prototyping as well as for large series production and makes it possible to achieve a good level of micrometric precision as well as good surface finish quality.

[0007] The UV-LIGA process requires tools, industrial equipment and techniques that are very different from conventional micro-manufacturing methods.

[0008] A typical process of the LIGA technique consists of: – depositing on a substrate a layer of 1 to 1000 µm of a photosensitive resin called photoresist; – if necessary, planarize the photoresist layer by mechanical machining; – carry out irradiation through a mask using a synchrotron or by exposure to ultraviolet rays; – develop, that is to say eliminate by chemical means, the unpolymerized photoresist portions and thereby create a photoresist cavity or mold; – carry out selective gold plating on the upper surfaces of the photoresist cavity in the case of producing a cavity on several levels; – repeat the previous steps to create cavities on several levels; – electroform a metal in this cavity in order to obtain the micromechanical component.

[0009] It is also possible to produce microparts which include more than a single element. For example, document EP 1 916 567 describes a process for mixed manufacturing of parts by photolithography, addition of inserts and electroforming. This process requires the assembly of at least two elements, one obtained by photolithography and galvanic growth, and the other by another manufacturing process, and it includes the following steps: – irradiation through a mask of a photosensitive resin layer applied to a substrate; – development of the photosensitive resin layer to form a polymerized resin mold; – placement of an added element obtained by another manufacturing process in the polymerized resin mold; – deposition of a metallic layer by electroforming on the substrate so that the growth of the metallic layer surrounds all or part of the added element; – obtaining the part by separation of the substrate from the electroformed metal layer secured to the added element and elimination of the photoresist mold.

The microstructures obtained according to the methods of the prior art have limited precision, which results from the nature of the LIGA process

[0011] The microstructures obtained according to the methods of the prior art are metallic microstructures made from a single metal, which is not always optimal, particularly for watchmaking applications. Indeed, it may be interesting, for aesthetic, tribological or more generally mechanical reasons, etc., to produce bimetal microstructures comprising at least one part made of a first metal inserted in a part made of a second metal.

[0012] Usually, to produce such bimetal microstructures, the insert (or inserts) in a first metal is (or are) attached in a traditional manner to the part in a second metal by embedding, crimping, screwing or other stamping.

[0013] The process based on photolithography and electroforming makes it possible to obtain shapes and precisions unmatched by traditional methods. Despite this very good precision, the demand for even better performance continues to increase.

[0014] With the LIGA process, the control of dimensions (diameter and verticality, for example for a hole), depends on many parameters. We can cite for example, the geometry of the resin (which itself depends on the parameters of the lithographic process), then the evolution of this geometry during electrodeposition. The size of the cavities, the type of photoresist, the height of the photoresist, the type and thickness of the metal deposited, for example, are important parameters.

[0015] Repeatability is extremely complicated to control due to all these factors.

[0016] It is therefore obvious that to obtain a hole precisely and repeatably, for example, in a microstructure manufactured by LIGA, rigorous control of the parameters mentioned above must be carried out. This is technically and economically unimaginable for all parameters. Each hole diameter and each thickness will require specific adjustments to these parameters. If a microstructure has several holes with different diameters and/or thicknesses, it is easy to understand that the precision obtained is the result of a series of compromises.

[0017] In the field of microstructures manufactured by UV photolithography and electroforming, there is no solution which makes it possible to obtain precisions lower than +/-2 µm, or even +/- 1 µm in the best case, in a reproducible manner in time. This resolution limit is mainly linked to the difficulty in obtaining the target value at the center of the tolerance interval. The resolution limit and geometric conformity, in particular the verticality of the sides, is the result of optimization and compromise, but is limited by the materials and installations used and is strongly linked to the indirect nature of the process. Indeed, a hole in a part, for example, is defined by a resin mold, followed by an electroforming step. The final result therefore depends on a multitude of parameters and manufacturing steps.

[0018] There is therefore a need to have a new technique which makes it possible to improve the precision of micro-mechanical components produced by the LIGA technique and without substantially increasing the cost of their production.

Object of the invention

The invention relates to a method and equipment for corrective machining, in particular by laser, of a large number of small parts previously produced by a LIGA process. The direct production of precise and repeatable dimensions has reached its limits with the UV-LIGA process. To ensure even higher accuracies and tolerances, targeted re-machining by force-free machining means, for example by a pulsed laser, is offered. The retouching of critical dimensions is done on identified and sketched elements.

[0020] More precisely, the equipment and the method of the invention make it possible to correct extremely quickly and reliably by force-free machining of parts previously produced by a LIGA process, said parts having been produced on a substrate and then transferred to another medium. The method and equipment of the invention make it possible to produce a plurality of parts of very precise dimensions, brought and arranged on a support and this at high speed and without substantially increasing their manufacturing cost.

The equipment and method of the invention make it possible to use machining machines without force, preferably by laser, for example by a femtosecond laser, which are extremely expensive machines, at their maximum capacity. This is key in the field of manufacturing timepieces but also precision medical parts such as used for example in endoscopes. A particular application aims to produce curved surfaces and holes and openings in LIGA parts with very high precision.

[0022] In a first aspect the invention is obtained by corrective machining equipment for microtechnical metal parts previously produced by a LIGA process, comprising a machining machine comprising a system for loading/unloading supports of metal parts, force-free machining means for machining said metal parts and a system for controlling said force-free machining means, said machining machine defining a horizontal plane X-Y and a vertical axis Z orthogonal to the horizontal plane X-Y.

[0023] Each support comprises, at least on one side, a surface arranged to fix a plurality of metal parts previously produced by the LIGA process.

The corrective machining equipment comprises a system for recording at least one target geometry and at least one predetermined reference X-Y-Z position specific to each metal part positioned on the support relative to a reference mark , said system for recording said target geometries and said X-Y-Z positions being arranged to cooperate with the system for controlling said force-free machining means.

[0025] The corrective machining equipment comprises a vision system and a calculation unit making it possible to recognize, in the reference frame, the 3D geometry and the positioning of the metal parts previously produced by the LIGA process and to determine a correction of the geometry to be provided in relation to the target geometry and to said recorded reference X-Y-Z position, at least the calculation unit being arranged to cooperate with the system for controlling the force-free machining means.

[0026] Said system for controlling said force-free machining means comprises a system for positioning said force-free machining means arranged to, before corrective machining of each metal part, move and position said force-free machining means in the reference mark relative to said metal part to be corrected and to carry out the corrective machining as a function of said correction of the geometry, so as to obtain said target geometry.

[0027] In one embodiment, said force-free machining means comprise a transmitter arranged to emit an electromagnetic wave.

[0028] In one embodiment, the transmitter is configured to emit an electromagnetic wave having a wavelength between 150nm and 1mm, preferably between 200nm and 15µm, even more preferably between 300nm and 5µm.

Advantageously the transmitter is a laser.

[0030] In one embodiment, said laser is a femtosecond laser, configured to emit pulses having a duration of less than 900 femtoseconds, preferably less than 400 femtoseconds.

[0031] In one embodiment, at least one reference mark is provided on said support of metal parts.

[0032] In an alternative embodiment, at least one reference mark is provided on at least one of said metal parts.

[0033] In one embodiment, at least one reference mark is provided on the machining machine.

[0034] In one embodiment, the vision system is arranged to carry out a 3D geometry and positioning measurement with a precision of less than 10 µm, preferably less than 5 µm, more preferably less than 2 µm, in at least one of the 3 axes X, Y, Z.

[0035] In one embodiment, said support is arranged to carry at least two assemblies containing metal parts of different types.

[0036] In one embodiment, the machining machine comprises a system for releasing, after corrective machining, at least part of the metal parts from their support.

[0037] In one embodiment, said positioning system comprises a 5-axis optical system, arranged to cooperate with the control system of said force-free machining means, to be able to orient the electromagnetic wave emitted in the 3 dimensions X-Y-Z .

[0038] In one embodiment, said system for controlling said force-free machining means is arranged to machine at least a portion of the metal parts according to different machining stages.

[0039] In one embodiment, each support is arranged to receive more than 10, preferably more than 100, preferably more than 1000, preferably more than 5000 metal parts, and said machining machine is adapted to be able to machine at less than 5000 pieces in less than 10000 seconds.

[0040] In a second aspect the invention is carried out by a method of corrective machining of microtechnical metal parts previously produced by a LIGA process, said method comprising the different steps (A-F) consisting of: A: providing, on a support parts, metal parts previously produced by a LIGA process; B: equip yourself with the corrective machining equipment as described and insert at least one of said part holder into said machining machine; C: record a target geometry and at least one predetermined reference X-Y-Z position specific to each metal part positioned on said part support relative to a reference mark; D: recognize, in said reference frame, the 3D geometry and the positioning of the metal parts, previously produced by the LIGA process, and determine a correction of the geometry to be made in relation to said target geometry and to said reference X-Y-Z position recorded at using said vision system and said computing unit; E: execute corrective machining steps of said metal parts by said force-free machining means, which are, before the corrective machining of each metal part, moved and positioned in the reference frame with respect to said metal part to be corrected , in order to carry out the corrective machining according to said correction of the geometry determined in step D to obtain said target geometry; F: release at least one of said metal parts from its support.

[0041] In one embodiment, the reference mark is provided on said support.

[0042] In variants, the reference mark provided on said part support was transferred from the substrate in which the metal parts were made by the LIGA process.

[0043] In one embodiment, said reference mark is produced on at least one surface of at least one metal part.

[0044] In one embodiment, said part support is a transfer film made at least partially from a polymer.

[0045] In one embodiment, the reference mark is provided on the machining machine.

[0046] The invention is also obtained by a metallic microtechnology part, obtained by the method as described, and having at least one portion which presents, between the dimensions of the corrected part and the target geometry, a difference less than 2 µm, preferably less than 1.5 µm.

[0047] In a variant, the metal microtechnology part, as described, comprises at least two surfaces of said metal microtechnology part which have been corrected with the method described.

Descriptions of the figures

[0048] The invention will be better understood on reading the detailed description of an exemplary embodiment made with reference to the appended figures among which: – Figure 1 represents steps of a LIGA process and a transfer process on a parts support according to the invention; – Figure 2 represents a parts support comprising metal parts produced by a LIGA process, according to the steps illustrated in Figure 1; – Figure 3 shows a schematic diagram of a force-free machining machine; – Figure 4 represents the diagram of part correction equipment comprising a force-free machining machine preferably comprising a femtosecond laser, a vision system and a calculation unit; – Figure 5 represents a vertical section of a part produced by a LIGA process; – Figure 6 represents a laser beam directed on a microtechnical part according to Figure 5 with a view to performing a shape correction by material ablation using a force-free machining system; – Figure 7 shows a laser beam directed on a microtechnical part, in a position to achieve a target diameter of an opening; – Figure 8 represents a metal part produced by a LIGA process and whose shape and/or dimension and/or surface condition has been corrected using force-free machining; – Figure 9 shows a multi-level micro-part, including holes, produced with the part correction equipment and the method according to the invention; – Figures 10-12 illustrate metal parts produced by the part correction equipment and the method according to the invention; – Figure 13 represents a parts support comprising metal parts produced by a LIGA process. Figure 13 also illustrates marks on the parts support; – Figure 14 illustrates a portion of a parts support comprising position markers near the metal parts on the parts support; – Figure 15 shows a substrate comprising metal parts produced by a LIGA process; – Figure 16 shows a flexible parts support comprising metal parts made by a LIGA process.

Description of embodiments of the invention

The invention relates to a method of corrective machining of small metal parts produced beforehand by a LIGA process. The process makes it possible to produce very high precision metal parts, i.e. having surfaces, dimensions and shapes, which are defined with precisions of less than 2µm, or even less than 1 µm.

[0050] Although a preferred application of the invention concerns the field of watchmaking, it is not limited to this field and can be applied to any field which benefits from small metal parts which have openings and/or or machined surfaces such as curved surfaces or surfaces defined by a polygon in at least one section of said metal part.

[0051] For example, the dimensions of the metal parts used in watch mechanisms are very small and it is very difficult to machine them with precision and at low costs and at high speed. The maximum outer diameter of these parts is typically between 0.5 and 3 mm, and the typical thickness is between 0.05 mm and 1 mm.

[0052] It is known that it is very difficult to load and unload individual microtechnology parts very quickly in a machining machine in order to ensure the rate allowed by machining. Standard methods use vibrating bowl loading or vision-guided flexible feeding systems that directly load micro-engineered parts into clamp fixtures, allowing perfect positioning of small metal parts before machining. These methods are very difficult to develop to achieve high levels of reliability and autonomy. In addition, they are incapable of reaching very high loading/unloading rates (we are talking about rates between 0.5 seconds and 1 second per part).

[0053] Producing metal parts whose desired geometry is produced with very high precision, typically of the order of a micrometer, by methods which are based on machining by applying a force requires machining part by part which is very expensive and does not always provide the required precision.

[0054] The equipment and the method of the invention propose a method based on carrying out a correction, without applying force, of the dimensions and/or shapes of parts produced by the LIGA process. It is understood here that the term “force-free” means machining without direct contact between a machining tool and the workpieces.

[0055] In the present description of the invention it is understood here that the term “machining” means a correction of shape and/or or dimension of at least one portion of a part at least partially previously produced by process LIGA. The term “machining” also includes a simple correction of the 3D shape of the parts without necessarily removing material from the parts.

[0056] In the present description, “force-free machining” is called unconventional machining in which there is no mechanical action transmitted by direct contact and force between a tool and the part, unlike conventional machining where there is direct contact between the tool and the workpiece and in which significant cutting forces are involved. Force-free machining is therefore machining without direct contact between the part to be machined and a machining tool which would be likely to exert a force or stress on said part. Force-free machining is machining with a machining force less than a Newton (N) or a specific cutting pressure less than N/mm<2>.

[0057] The equipment and method of the invention make it possible to carry out a correction of the desired dimensions and/or shape by said force-free machining, also defined as “force-free correction”. The metal parts are produced in batches using a LIGA technique and with an average precision, typically +/- 2 microns, characteristic of the LIGA process, and are finalized by final machining without applying force.

[0058] It is understood that all the embodiments and variants of the equipment of the invention can be combined with each other according to any technically compatible combination. It is also understood that all the embodiments and variants of the method of the invention can be combined with each other according to any technically compatible combination.

[0059] The equipment and method of the invention may comprise at least one of the following force-free machining means: – machining by emission of an electromagnetic wave, for example a beam of light such as a laser beam; – plasma machining, preferably directional plasma; – machining by microwaves, preferably directional microwaves; – machining by electrochemical process, preferably local electrochemical attack (ECM). The ECM process is a machining method generally used for deburring, hollowing, polishing or drilling. Electrochemical machining requires two elementary components: the electrolyte and electric current. The “electrolyte” is, for example, salt water which constitutes the conductor of the electric current; – machining by magnetic effect; – machining by beam of electrons, protons or neutrons; – machining using an electric arc, for example by sinking electroerosion, commonly also called EDM (English term meaning “electrical discharge machining”); – wire machining and electroerosion.

[0060] The various force-free machining methods do not necessarily have to remove material. For example, by induction a portion of a part can undergo deformation, such as a slight correction of the radius of curvature of a thin membrane.

[0061] It is understood that at least two machining means can be implemented, whether in operation at the same time or according to delayed machining times. For example, the metal parts can first undergo radiation with an infrared flow in order to soften or deform a metal part 10, 10', followed by local machining by femto laser.

Description of Equipment

[0062] More precisely, in a first aspect, the invention relates to equipment for corrective machining of metal parts 10, 10' of microtechnology produced previously by a LIGA process, comprising a machining machine 200. The machining machine 200 preferably comprises a loading/unloading system 300 of part supports 2 for metal parts 10, 10', force-free machining means for machining said metal parts 10, 10' and a system for controlling said force-free machining means strength. As illustrated in an example in Figure 4, said machining machine 200 defines a horizontal plane X-Y and a vertical axis Z orthogonal to the horizontal plane X-Y.

[0063] Each part support 2 comprises, at least on one side, a surface 2a, 2b arranged to fix a plurality of metal parts 10, 10' previously produced by the LIGA process.

[0064] The corrective machining equipment comprises a system for recording at least one target geometry and at least one predetermined reference X-Y-Z position specific to each metal part 10, 10' positioned on the support 2 in relation to to a reference mark, said system for recording said target geometries and said X-Y-Z positions being arranged to cooperate with the system for controlling said force-free machining means.

[0065] The corrective machining equipment comprises a vision system 120 and a calculation unit 130 making it possible to recognize, in the reference frame, the 3D geometry and the positioning of the metal parts 10, 10' previously produced by the LIGA process and to determine a correction of the geometry to be made in relation to the target geometry and to said recorded reference X-Y-Z position, at least the calculation unit 130 being arranged to cooperate with the system for controlling the force-free machining means. Advantageously a lighting system 140 of the parts 10, 10' or part of the part support 2 is adapted in the machining equipment, preferably adapted to the vision system 120 as illustrated in Figure 4. The system d The lighting can emit a 142 UV, visible or infrared beam which can be divergent, collimated or focused.

[0066] Said system for controlling said force-free machining means comprises a positioning system for said force-free machining means arranged to, before the corrective machining of each metal part 10, 10', move and position said means of force-free machining in the reference mark relative to said metal part 10, 10' to be corrected and to carry out the corrective machining as a function of said correction of the geometry, so as to obtain said target geometry. In Figure 4 said movement and positioning of the force-free machining means in the X-Y-Z space is illustrated by the symbols ΔX, ΔY, ΔZ.

[0067] In a preferred embodiment, illustrated in Figure 3, the force-free machining means comprise a transmitter 100 arranged to emit an electromagnetic wave 110. In other embodiments, the transmitter 100 is a transmitter of particles such as electrons, protons or neutrons. In other embodiments, the transmitter comprises a generator of an electric and/or magnetic field, for example an induction coil. In other embodiments, the transmitter 100 is a part adapted to emit an electric arc. Of course, a transmitter can include at least two transmitters of different types.

Preferably, the transmitter 100 is configured to emit an electromagnetic wave 110 having a wavelength between 150nm and 1mm, preferably between 200nm and 15µm, even more preferably between 300nm and 5µm.

[0069] In one embodiment, the transmitter 100 is a laser, preferably pulsed, configured to emit a laser beam 110. Latest generation lasers with ultra-short pulses allow the controlled and precise removal of material. The proposed solution combines corrective machining by ultra-short wave laser on components previously manufactured by LIGA technology.

Advantageously, said laser 100 can be a femtosecond laser, configured to emit pulses having a duration of less than 900 femtoseconds, preferably less than 400 femtoseconds. Machining a surface and/or internal hole of a metal part by laser, preferably a 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 aperture diameters are between 0.05 mm and 2 mm.

[0071] The typical pulse durations of a pulsed laser 100 are preferably between 1000 fs and 40 fs.

[0072] Preferably, a transmitter 100 can emit 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.

Advantageously, the transmitter 100 is a femtosecond laser emitting a UV, green or infrared beam. A 343 nm UV femtosecond laser and a 515 nm green femtosecond laser can achieve a roughness of less than 50 nm on metal parts. In the case of an IR laser emitting a beam with a wavelength of 1030nm, a typical roughness is 100 nm or better.

[0074] In embodiments, the maximum energy per laser pulse is advantageously close to 2 mJ.

[0075] The power of the laser is typically 20 W, but must be adapted depending on the material of the metal parts 10, 10'.

[0076] One of the advantages of manufacturing microstructures by photolithography and electroforming is being able to manufacture a large number of parts on the same basic substrate.

[0077] Retouching can therefore be done when the metal parts 10, 10' are all still positioned on the part support 2 in the same configuration as they had on the substrate 1 during the LIGA process.

[0078] As the parts are positioned on said parts support 2 in a manner identical to the configuration of the substrate 1, there is no need for a system for feeding and orienting the metal parts 10, 10'. A movement system in the X-Y plane for the part support 2 or for the transmitter 100 is sufficient to be able to work a large number of metal parts 10, 10'.

[0079] Another advantage of this manufacturing process is that the positioning of each part 10, 10' on the part support 2 is perfectly known. This is not essential for the corrective machining equipment and method of the invention, but can advantageously be implemented in one embodiment. For example, the positioning of each part 10, 10', of each hole, can be referenced. Preferably, the parts support 2 is a flexible support. The transfer of parts from substrate 1 on which parts 10, 10' are produced by LIGA onto a parts support is illustrated in Figure 1 and described in more detail in the paragraph relating to the process of the invention.

[0080] We can therefore preferably base ourselves on this positioning to perfectly center the retouching by the transmitter 100 after an optical measurement of the location of the hole, for example. Retouching by micro-machining by the transmitter 100 is then facilitated, because the positions of the metal parts 10, 10' are perfectly known. In order to avoid high machining times, re-machining will only be carried out to bring the geometries into the correct dimensions. The geometry (the diameter in the frame of a hole, for example), will be sketched using LIGA technology. Laser re-machining will only be used to complete the dimensions of the hole on the last microns and obtain the required verticality and precision.

[0081] The principle of re-machining is illustrated in Figures 5 to 8. Figure 5 illustrates a metal part 10 which comprises a hole 12 of which at least one vertical section does not have a uniform diameter and whose average diameter D0 does not have the correct value. A laser beam 110 is moved (Figure 6) to the predetermined location making it possible to correct (Figure 7) the diameter of the hole to its desired value D1 (Figure 8).

[0082] In one embodiment, illustrated in Figure 4, the corrective machining equipment comprises a loading/unloading system 300 of part supports 2.

Reference marks

[0083] In one embodiment the reference mark is provided on said support 2 of metal parts 10, 10'.

[0084] Figure 13 illustrates a parts support 2 comprising several reference marks 20, 20', 20'', 20'''.

[0085] Figure 14 illustrates reference mark marks 21, 22, 23, 24, 25, 26, 27, 28 which are located near the parts 10, 10', 10", 10''' to be machined.

[0086] The reference mark does not necessarily have to be on said part support 2. Indeed, in another embodiment the reference mark is provided on the machining machine 200.

[0087] In an advantageous variant, the reference mark is at least one alignment mark made on a surface of said support 2 of metal parts 10, 10'. The reference mark may for example consist of one or more alignment patterns, for example cross-shaped patterns.

[0088] In a variant, the reference mark is at least one alignment mark made on a surface of said part support 2, near each part 10,10'. In a variant, each metal part 10, 10', 10", 10"' has its own reference mark near it.

[0089] In a variant, the reference mark is an element of the metal part 10, 10'.

[0090] Of course the equipment and the method of the invention can implement different marks, for example at least one mark on the parts support and at least one mark on a frame which holds the parts support.

Vision system(s)

[0091] In one embodiment, the vision system 120 is arranged to carry out a 3D geometry and positioning measurement with a precision of less than 10 µm, preferably less than 5 µm, more preferably less than 2 µm, in at least one of the 3 axes X, Y, Z.

[0092] Advantageously, the focusing and the 3D movements of the beam 110 are carried out by an optical unit, for example an optical unit which may comprise a system for adapting the shape of a laser beam and an orientation of 3, 4 or 5 axes in space. For example, the focusing of the laser beam can be adapted during the correction operation of the metal parts 10, 10'.

[0093] In an advantageous and preferred embodiment, the position measuring device is adapted to the positioning system of a laser 100. In this case the device for measuring the X-Y-Z position of the metal parts 10, 10' comprises an optical vision system 120 which is preferably attached to said laser 100, as illustrated in Figure 4. Figure 4 illustrates an example of an arrangement of such a vision system 120 comprising an image sensor adapted to form images in a horizontal plane X-Y and preferably an illumination system 140 adapted to emit an illumination beam 142. The position measurement system Advantageously, such a system for measuring the vertical position is an optical system comprising a dynamic focusing system in the vertical direction Z. It is understood that the 2D visualization system can be arranged in order 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 provide 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 upper face or the rear face of the metal parts 10, 10'. This makes it possible to increase the precision of the 3D X-Y-Z measurement of metal parts 10, 10'.

[0094] Advantageously, the device for measuring the position 3 axes X, Y, Z.

Other embodiments

[0095] In an alternative embodiment, the force-free machining means comprise a transmitter and said positioning system comprises a 5-axis orientation system, arranged to cooperate with the control system of said transmitter 100. This makes it possible to orient the machining beam 110 emitted in the 3 dimensions X-Y-Z. In a variant, the transmitter 100 is a laser and the orientation system comprises an optical system in order to be able to orient the beam 110 emitted in space.

[0096] In variants of the invention, said system for controlling the force-free machining means can be arranged to machine at least a portion of the metal parts 10, 10' according to different machining steps. For example, part of the parts 10, 10' fixed on said part support 2 would need to have a height, defined in the Z axis, reduced by 3µm and another part of the parts 10, 10' would require a correction of the height of only 1µm.

[0097] Advantageously, a parts support 2 is arranged to receive more than 10, preferably more than 100, preferably more than 1000, preferably more than 5000 metal parts 10, 10', and said machining machine 200 can be adapted to be able to machine at least 5000 parts in less than 10000 seconds.

[0098] In one embodiment, not illustrated in the Figures, the machining machine 200 comprises a system for releasing, after their machining, at least part of the metal parts 10, 10' from their support 2.

[0099] In a particularly advantageous manner, the machining machine 200 comprises a machining program for machining a predetermined number of said plurality of metal parts 10, 10'. In variants, the machining program can make it possible to machine two sets of metal parts 10, 10' by two different lasers of the machining machine 200 or can make it possible to machine two sets of parts by two modes of operation. different operation of a transmitter such as a pulsed laser. These different modes of operation may consist of the use of different energies or powers, and/or by adjusting the numerical aperture of the laser beam.

[0100] In an alternative embodiment, the machining machine 200 comprises a machining program for machining at least a portion of the metal parts 10, 10' according to different machining steps. For example, each part can be treated to produce a hole, followed by an operation for processing an edge or a circumference of the metal part 10, 10'.

[0101] In one embodiment, the machining machine of the invention 200 may comprise at least two lasers which produce non-parallel beams. For example, a first femtosecond laser can be adapted to make apertures and another laser can be used to produce a beam that is not parallel to the beam of the first laser.

[0102] Advantageously, the machining machine 200 of the invention can comprise at least one multibeam optic, adapted to carry out simultaneous machining of several parts at the same time.

Process

[0103] The invention also relates to a process for corrective machining of microtechnology metal parts previously produced by a LIGA process, said process comprising the different steps (A-F) consisting of: A:: providing parts on a part support 2 metal 10, 10' previously produced by a LIGA process; B:: equip yourself with the corrective machining equipment, as described, and insert at least one of said part support 2 into said machining machine 200; C:: record a target geometry and at least one predetermined reference X-Y-Z position specific to each metal part 10, 10' positioned on said part support 2 relative to a reference mark 20, 20', 20", 20"' , 21, 22, 23, 24, 25, 26, 27, 28; D:: recognize, in said reference frame, the 3D geometry and the positioning of the metal parts 10, 10', previously produced by LIGA, and determine a correction of the geometry to be made in relation to said target geometry and to said position X-Y-Z reference values recorded using said vision system 120 and said calculation unit 130; E: execute corrective machining steps of said metal parts 10, 10' by said force-free machining means which are, before the corrective machining of each metal part 10, 10' moved and positioned in the reference mark relative to to said metal part 10, 10' to be corrected, and to carry out corrective machining as a function of said correction of the geometry determined in step D, so as to obtain said target geometry; F: release at least one of said metal parts 10, 10' from its support 2.

[0104] In one embodiment, the reference mark is provided on said support 2.

[0105] In an advantageous embodiment, the reference mark provided on said support 2 was transferred from the substrate 1 in which the metal parts 10, 10' were made by the LIGA process.

[0106] Once the metal parts 10, 10' are loaded and referenced on the X-Y-Z table of the machining machine 200, the rate of corrective machining of the metal parts 10, 10' arranged on a part support 2 is dictated by the corrective machining time, for example by the corrective machining time of the hole - typically 0.5 to 1.5 sec - plus the time of moving the table from one metal part 10, 10' to another. The corrective machining time is typically 0.3 to 1 second depending on the size and the distance between each metal part 10, 10'. For 10, 10' parts with an external diameter of 0.9 mm, more than 8,000 10, 10' metal parts can be arranged on a round support of 150 mm in diameter. Loading and unloading part supports 2 is extremely easy, and even if it is not fast, the time is divided by the number of parts 10, 10' per support 2. An automatic loading system for part supports 2 allows the machining machine to operate completely autonomously for very long periods, despite a cycle time for corrective machining of the parts which is typically around 1 second.

[0107] In a typical example, the vision system 120 proceeds by taking a picture of each of the metal parts 10, 10' individually. In an advantageous example, in order to reconstruct the X-Y-Z position of all the metal parts 10, 10', the vision system 120 proceeds by successively taking pictures of 10 to 15 metal parts. In a variant of the method, during step E, the positioning of the force-free machining means 100, relative to said metal parts 10, 10', is done by a movement in an X-Y plane or in the X-Y-Z space of said means machining without force 100.

[0108] In another variant, during step E, the positioning of the force-free machining means relative to said metal parts 10, 10' is done by moving said part support 2.

[0109] It is also possible that, during step E, the positioning of the force-free machining means is done by moving said transmitter 100 and also said part support 2. These two movements do not necessarily have to be simultaneous.

[0110] In one embodiment, the step D of recognizing the geometry and the position of the metal parts 10, 10' is carried out successively for all the metal parts 10, 10' just before their machining.

[0111] In a variant, at least one step of cleaning the parts 10, 10' is carried out between two corrective machining cycles of the metal parts 10, 10'.

[0112] In one embodiment, the corrective machining step comprises at least the correction of an opening 10a, 10b, 10c, 12 in at least one of said plurality of metal parts 10, 10'.

[0113] The part supports 2 can be of all shapes, typically rectangular, square or circular. Preferably, the support is a flexible film made from a polymer. In this case the film is held in a frame as support. The support is for example an adhesive film commonly used in the microelectronics industry and known by the English term “tape”. This type of film is used in this industry to enable sawing, machining or thinning of wafers, for example.

[0114] The parts support 2 can be a transparent glass support, for example made of borosilicate glass. The parts support 2 can be a wafer, commonly called a wafer in English, made of semiconductor material, metal alloy, ceramic material or other material.

[0115] In one embodiment, the parts support 2 can be a combination of the supports described above.

[0116] If the part support 2 is a polymer film, the machining of the parts 10,10' can be accompanied by drilling of the support 2. For example, when widening a hole, a laser can pierce the parts support 2 and thus more easily evacuate the metal removed from the parts 10, 10'.

[0117] If the parts support 2 is made of a hard material and includes an adhesion film, the parts supports 2 can be pierced. By using part supports 2 which are drilled, with openings provided at each position intended to position the metal parts 10, 10', it is possible to facilitate the corrective machining of the parts as well as their release. Indeed, during the corrective machining of the parts (step E of the process described) the fact of having an opening under each metal part makes it possible to easily pass through the adherent film of the part support 2 which will be pierced, forming an opening in the film member. Thus, the material of the metal part 10, 10' as well as that of the adhesive film can be evacuated through the opening of the hard part support 2 which is located under the metal part 10, 10'. This evacuation can be done by suction or by a pressurization system.

[0118] In variants, said adhesion film can be a semi-adherent or adhesive layer such as a double-sided adhesive strip, for example a polymer film, which is fixed on a parts support 2. Certain types adhesive films used in microtechnology ensure adhesion strength without having to use glues. These films are commonly called “blue tapes” and known to those skilled in the art of microtechnology.

[0119] Advantageously, in a variant, a force-free machining system, using a laser 100, may comprise optics delivering more than one laser beam, typically 2, 4, 9, 16 or more beams. This allows the simultaneous machining of several metal parts 10, 10' at the same time.

[0120] With a suitable optical element, it is possible to carry out almost any correction of parts 10, 10' ensuring great homogeneity and high overall efficiency. By combining a multibeam 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 on the metal part 10, 10' by said scanner.

[0121] The company Pulsar Photonics for example, whose reference is found under the website https://www.pulsar-photonics.de/, offers a solution of a multibeam scanner for multibeam laser processing. Such a system comprises at least one beam scanner based on a galvano system. Selectable beam splitting with a multi-beam module generates a fixed beam arrangement in the scanning system work plane. This approach makes it possible to multiply the speed of the process in the production of periodic structures.

[0122] Thanks to 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 n x m or n and m are different numbers. It is understood that laser beams may be different, for example they may have a different focal length.

[0123] The use of a multi-beam system makes it possible to achieve efficient parallel production of identical structures in a single step.

[0124] It is thus possible to overcome the power limitations, essentially of physical origin, of numerous “ultra short pulse” processes and thus to considerably increase the efficiency of the processes.

[0125] The fields of application are drilling, parallel processing of several components or general parallelization of processes.

[0126] The release of the metal parts 10, 10', fixed to the parts support 2 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 bonding interfaces. Release can also be achieved by exposure to heat or flashes of infrared radiation. Said UV and/or infrared radiation can be produced by pulsed power sources.

[0127] In variants, step F of releasing the parts can be done in various ways: – by application of 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.

Transfer technique on part support 2 after LIGA process

[0128] The technique of transferring parts 10,10' produced by the LIGA process onto a part support 2 is now described in detail and is referred to in Figure 1.

[0129] The advantage of the LIGA technique is to produce metallic microcomponents with very high precision in X and Y and with a thickness of up to several millimeters. It is also possible to apply the process in several stages to obtain a microcomponent at several levels, each level being built on the previous one.

[0130] The positioning of the metal parts 10, 10' in relation to each other as well as in relation to reference marks is known, because the parts remain throughout the process in the same position as their original position on the wafer.

[0131] Substrate 1 is generally a support plate of glass, metal or silicon on which is deposited a conductive layer produced by evaporation of chromium and gold, for example. In the case where the substrate is naturally conductive, it is not necessary to deposit a conductive layer. For the remainder of the description, the “conductive substrate” is therefore either the naturally conductive substrate, or the substrate with a conductive layer on its surface. On the conductive substrate is deposited a layer of photosensitive resin, preferably of the negative type sensitive to UV ultraviolet rays, hereinafter called "photoresist", typically from the SU-8 family of MicroChem Corporation. It is also possible to use dry photosensitive resin, that is to say without solvent or with very low levels of solvent. Alternatively, the photoresist could be of the positive type.

[0132] This photoresist layer is polymerized after selective irradiation. In the particular case of a negative type photoresist, the irradiated parts are polymerized while the non-irradiated parts are not polymerized. If necessary, the photoresist layer is flattened before irradiation.

[0133] Once developed, that is to say after elimination of the non-polymerized photoresist parts, a photoresist mold 3 is obtained. This mold 3 is illustrated in Figure 1, step 1a and the parts of photoresist eliminated reveal cavities. On a single-level mold, these cavities reveal the conductive substrate 1.

[0134] The next step consists of filling the mold 3 with photoresist according to an electroforming operation, the conductivity of the conductive substrate 1 allows metal deposition in the cavities of the mold 3 and when the level defined by the polymerized layer of the mold 3 is reached, the metallization is interrupted. We see in the figure of step 1b, a slight overflow of the metal part 5. It is customary, but not necessary, to extend the electroforming once the upper level of the mold 3 has been reached to ensure that all the cavities are filled. Figure 1b illustrates the state in which the assembly finds itself at the end of these operations. The electroformed metallic layer forms a plurality of metallic portions 5 linked together by the photoresist mold 3 and secured to the conductive substrate 1.

[0135] In this description, the “external face” is the face of the metal parts corresponding to the free side of the metallization by electroforming. The “internal face” is that which, during metallization, is in contact with the conductive substrate 1. Metallization by electroforming creates metal portions 5 with a raw external face 5a and a raw internal face 5b. They are called “raw” because they are a direct result of electroforming, either unmachined or polished.

[0136] A first machining step is carried out on the raw external face 5a of the microparts to obtain the machined external face 5c of the metal portions 5 in a desired state. The sides of the metal portions 5 correspond to the vertical part of the metal portions 5 in contact with the mold 3 during the electroforming phase. The height of the metal portions 5 is at this stage approximate. The result is illustrated in step 1c allowing you to see the machined external face 5c of the metal portions 5.

[0137] The next step consists of eliminating the photosensitive resin mold 3 by chemical attack. The conductive substrate 1 will remain integral with the plurality of metal portions, as illustrated in step 1d.

[0138] The next step is the application of a binder resin 4. This resin will cover the machined external face 5c and the sides of the metal portions 5 and fill the cavities left free by the elimination of the mold 3. that is to say be in contact with the conductive substrate 1. This binder resin 4 will also exceed the height of the metal portions as illustrated in step 1e.

[0139] Next comes the preparation of the assembly by lowering and flattening the binder resin 4 to form a flat reference surface 4' parallel to the conductive substrate 1. The result is illustrated in step 1f. It should be noted that the lowering of the binder resin 4 is done so that the machined external face 5c of the metal portions 5 remains covered with binder resin 4. This assembly is released from the conductive substrate 1 by machining the latter or any other method of releasing the conductive substrate 1. All of the metal portions 5 and the binder resin 4 form a rigid whole. The result is shown in Figure 1g.

[0140] Said binder resin 4 can be, for example, a hot melt glue based on natural shellac and a mineral filler which can be in the form of powder or in pieces. The cement product B67 or MelBo325 from Stettler Sapphire (internet ref: https://www.stettlersapphire.ch/index.php/fr/), for example, can be used.

[0141] During the same machining operation of the conductive substrate 1, or a separate operation, the raw internal face 5b of the metal portions is machined to obtain the machined internal face 5d. The machining operation will reduce the height of the assembly until a desired height of the metal parts 10, 10' to be produced is reached. The result is visible in step 1h of Figure 1.

[0142] A transfer film, which is the part support 2, is applied to the machined internal face 5d of the metal portions 5 (see step 1i). Once the transfer film 2 is in place, the binder resin 4 can be removed by dissolution for example. Thus the metal portions 5 form the metal parts 10, 10' which will subsequently undergo a correction of dimensions or shape according to the force-free machining process as described in this document. The metal parts 10, 10' are linked together by the transfer film serving as part support 2 (see step 1j, Figure 1). The metal parts 10, 10' thus find themselves in the same position in the X-Y plane as during the manufacture of the photoresist mold as well as all the other steps in which the substrate 1 was present.

[0143] It is also understood that the force-free machining equipment can be adapted to carry out a first corrective machining cycle and that the metal parts 10, 10' are finished by another process such as a mechanical or chemical process. For example, pierced metal parts 10, 10' can 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 10, 10' on a part support 2. It is also understood that, in one embodiment, the machining machine 200 may include means for depositing a coating on the parts 10, 10' before or after their machining.

[0144] In an advantageous embodiment, all the parts 10, 10' can undergo a first corrective machining step which can be a surface preparation step carried out for example by said femtosecond pulse laser. In a variant, all of the metal parts 10, 10' can undergo a cleaning step and/or deposition of a layer.

[0145] Depositing a layer before corrective machining by the femtosecond laser makes it possible to better delimit the corrective machining zone. This layer can be removed after the corrective machining process.

[0146] It is understood that the corrective machining conditions can be adapted depending on the location (i.e. drawer) of a cassette system 300 of the corrective machining equipment of the invention. Thus, a first drawer may comprise a support 2 with parts 10, 10' in which a hole must be corrected and another drawer may comprise another support with parts whose surface must be corrected or on which a predetermined shape must be executed.

[0147] In one embodiment, the parts support 2 in a drawer of a cassette system 300 can undergo several corrective machining cycles. For example, during a first cycle all the parts 10, 10' are processed to correct a hole and during a second loading of part supports 2 into the machining machine 200, all the part supports 2 can be passed through the machining machine in order to correct for example an edge of the parts 10, 10'.

[0148] In one embodiment, during at least a second machining cycle, at least one other type of laser can be used. This laser may be another femtosecond laser.

[0149] Depending on the application, it is understood that the parts 10, 10' do not necessarily have to be arranged in a homogeneous manner on their part support 2. For example, the metal parts 10, 10' can be arranged according to a arrangement in the shape of a disk or rectangle.

[0150] In one embodiment the parts 10, 10' can be fixed on both sides of a parts support 2, for example by temporary gluing. A double-sided arrangement (not illustrated in the Figures) makes it possible to increase, for example by a factor of 2, the speed of corrective machining by the machining machine 200 of the invention.

[0151] It is understood that an inspection system can be used to monitor the dimensions of the corrected parts and to adapt the corrective machining parameters of the laser machine in order to allow autonomous and more precise production.

Metal parts made

[0152] There is no limitation in shape or 3D dimension of the metal parts 10, 10' produced by the equipment and the method of the invention.

[0153] The metal parts 10, 10' are typically of millimetric or micrometric dimensions. Femtosecond laser machining allows very high machining accuracies, typically smaller than ±1 µm. Surface roughness in cutting mode can reach roughness of 50nm or lower.

[0154] In one embodiment, a metallic microtechnology part 10, 10', is obtained by the method described and comprises at least one portion which presents, between the dimensions of the corrected part and the target geometry, a difference less than 2 µm, preferably less than 1.5 µm.

[0155] In another embodiment at least two surfaces of said metallic microtechnology part 10, 10' have been corrected with the method according to the invention.

[0156] Figures 9-12 illustrate metal parts produced by the part correction equipment and the method according to the invention.

[0157] Figure 9 represents a metal part 10 comprising structures made in 3 different planes P1, P2, P3 and comprising openings 10a, 10b, 10c.

[0158] Figure 10 shows a watch anchor produced according to the method of the invention.

[0159] Figure 11 shows a clockwork toothed wheel produced according to the method of the invention.

[0160] Figure 12 shows a connector part produced according to the method of the invention. The part 10 illustrated in Figure 12 may comprise at least one surface 10e, 10d which has been corrected with the method and the machining equipment according to the invention.

Example of application and configuration of corrective machining equipment for microtechnology metal parts (10,10') according to the invention.

[0161] The following example shows a case of application with metal parts 10, 10' on part supports 2 having a diameter of 150 mm. For parts 10, 10' having a diameter of 0.9 mm, approximately 8,000 parts can be produced on a part support 2 which is preferably a wafer and achieve corrective machining rates of approximately 1 second, this is that is to say between 8 and 10 times lower than what could be obtained with a conventional approach.

[0162] In a preferred configuration, the corrective machining equipment comprises: – a system for loading/unloading at least 25 part supports 2; – a measuring system 120 capable of very precisely measuring the position XYZ of each metal part 10, 10'; – a machining machine 200 comprising a femtosecond laser.

[0163] In the example, 8,000 metal parts 10, 10' can be aligned on a single parts support 2. The loading and unloading system is preferably a "cassette" type system comprising a plurality of drawers, each drawer being adapted to contain a single wafer.

[0164] The different operations can take the following times: – laser machining per part: 0.5 to 0.6 sec; – repositioning of the X-Y table: 0.3 sec; – charging and discharging by part support 2: 120 sec; – time limits for measurements: 60 sec.

[0165] This indicates a corrective machining and measurement time for parts 10, 10' typically below 2 seconds, more precisely 0.92 sec for the example described.

[0166] In the exemplary embodiment, the cassette system will therefore include a maximum of 25x8000 parts to be machined, therefore a maximum of 200,000 parts 10, 10'.

[0167] The method and the machining machine 200 of the example make it possible to insert the part support 2 under a femtosecond laser 100 and to correct all the parts 10, 10' on a single part support 2. When all the parts 10, 10' fixed on a parts support 2 are corrected, it is unloaded towards a drawer of a cassette system 300 associated with the machining machine 200 and corrective machining of the metal parts fixed on a second support for parts 2', 2", 2"' and so on.

Claims (22)

1. Equipment for corrective machining of metal parts (10, 10') of microtechnology previously produced by a LIGA process, comprising a machining machine (200) comprising a loading/unloading system (300) of supports (2) of metal parts (10, 10'), force-free machining means for machining said metal parts (10, 10') and a system for controlling said force-free machining means, said machining machine (200) defining a horizontal plane X-Y and a vertical axis Z orthogonal to the horizontal plane X-Y, characterized in that – each support (2) comprises, at least on one face, a surface arranged to fix a plurality of metal parts (10, 10') previously produced by the LIGA process; – the corrective machining equipment comprises a system for recording at least one target geometry and at least one predetermined reference X-Y-Z position specific to each metal part (10, 10') positioned on the support (2) relative to a reference frame, said system for recording said target geometries and said X-Y-Z positions being arranged to cooperate with the system for controlling said force-free machining means; – the corrective machining equipment comprises a vision system (120) and a calculation unit (130) making it possible to recognize, in the reference frame, the 3D geometry and the positioning of the metal parts (10, 10') produced previously by LIGA process and to determine a correction of the geometry to be made in relation to the target geometry and to said recorded reference X-Y-Z position, at least the calculation unit being arranged to cooperate with the system for controlling the machining means without force; – said system for controlling said force-free machining means comprises a positioning system for said force-free machining means arranged to, before corrective machining of each metal part (10, 10'), move and position said means of machining without force in the reference mark relative to said metal part (10, 10') to be corrected and to carry out the corrective machining as a function of said correction of the geometry, so as to obtain said target geometry. 2. Corrective machining equipment according to claim 1, characterized in that said force-free machining means comprise a transmitter (100) arranged to emit an electromagnetic wave. 3. Corrective machining equipment according to claim 2, characterized in that the transmitter (100) is configured to emit an electromagnetic wave having a wavelength between 150 nm and 1 mm, preferably between 200nm and 15 µm, again more preferably between 300 nm and 5 µm. 4. Corrective machining equipment according to claim 3, characterized in that the transmitter (100) is a laser. 5. Corrective machining equipment according to claim 4, characterized in that said laser (100) is a femtosecond laser, configured to emit pulses having a duration of less than 900 femtoseconds, preferably less than 400 femtoseconds. 6. Corrective machining equipment according to one of claims 1 to 5, characterized in that at least one reference mark is provided on said support (2) of metal parts (10, 10'). 7. Corrective machining equipment according to one of claims 1 to 6, characterized in that at least one reference mark is provided on at least one of said metal parts (10, 10'). 8. Corrective machining equipment according to one of claims 1 to 7, characterized in that at least one reference mark is provided on the machining machine (200). 9. Corrective machining equipment according to one of claims 1 to 8, characterized in that the vision system is arranged to carry out a 3D geometry and positioning measurement with a precision less than 10 µm, preferably less than 5 µm, more preferably less than 2 µm, in at least one of the 3 axes X, Y, Z. 10. Corrective machining equipment according to one of claims 1 to 9, characterized in that the support (2) is arranged to carry at least two assemblies containing metal parts (10, 10') of different types. 11. Corrective machining equipment according to one of claims 1 to 10, characterized in that the machining machine (200) comprises a system for releasing, after their corrective machining, at least part of the metal parts (10, 10') from their support (2). 12. Corrective machining equipment according to one of claims 2 to 11, characterized in that said positioning system comprises a 5-axis optical system, arranged to cooperate with the control system of said force-free machining means (100 ), to be able to orient the electromagnetic wave (110) emitted in the 3 dimensions X-Y-Z. 13. Machining equipment according to one of claims 1 to 12, characterized in that said system for controlling said force-free machining means (100) is arranged to machine at least a portion of the metal parts (10, 10' ) according to different machining steps. 14. Corrective machining equipment according to one of claims 1 to 13, characterized in that each support (2) is arranged to receive more than 10, preferably more than 100, preferably more than 1000, preferably more than 5000 metal parts (10, 10'), and in that said machining machine (200) is adapted to be able to machine at least 5000 parts in less than 10000 seconds. 15. Method for corrective machining of microtechnical metal parts (10, 10') previously produced by a LIGA process, said method comprising the different steps (A-F) consisting of: A: providing, on a parts support (2), metal parts (10, 10') previously produced by a LIGA process; B: equip yourself with the corrective machining equipment according to one of claims 1 to 14 and insert at least one of said part support (2) into said machining machine (200); C: record a target geometry and at least one predetermined reference X-Y-Z position specific to each metal part (10, 10') positioned on said part support (2) relative to a reference mark (20-20'", 21 -28); D: recognize, in said reference mark (20-20'", 21-28) the 3D geometry and the positioning of the metal parts (10, 10'), previously produced by the LIGA process, and determine a correction of the geometry to bring with respect to said target geometry and said reference X-Y-Z position recorded using said vision system (120) and said calculation unit (130); E: execute corrective machining steps of said metal parts (10, 10') by said force-free machining means (100), which are, before the corrective machining of each metal part (10, 10'), moved And positioned in the reference mark relative to said metal part (10, 10') to be corrected, in order to carry out the corrective machining as a function of said correction of the geometry determined in step D to obtain said target geometry; F: release at least one of said metal parts (10, 10') from its support (2). 16. Method according to claim 15, characterized in that the reference mark (20-20'", 21-28) is provided on said support (2). 17. Method according to one of claims 15 and 16, characterized in that the reference mark provided on said part support (2) has been transferred from the substrate (1) in which the metal parts (10, 10) were made ') by the LIGA process. 18. Method according to one of claims 15 to 17, characterized in that said reference mark (20-20'", 21-28) is produced on at least one surface of at least one metal part. 19. Method according to one of claims 15 to 18, characterized in that the reference mark is provided on the machining machine (200). 20. Method according to one of claims 15 to 19, characterized in that said part support (2) is a transfer film made at least partially from a polymer. 21. Metallic microtechnology part (10, 10'), obtained by the method according to one of claims 15 to 20, and having at least one portion which presents, between the dimensions of the corrected part and the target geometry, a deviation less than 2 µm, preferably less than 1.5 µm. 22. Metal microtechnology part (10, 10') according to claim 21, characterized in that at least two surfaces of said metal microtechnology part (10, 10') have been corrected with the method according to one of the claims 15 to 20.