A method of manufacturing a timepiece component.

[0001] la present invention relates to a method of manufacturing a timepiece component made of a micro-machinable material.

[0002] il is known components to be manufactured timekeeping from a micro-machinable material such as silicon and by techniques of microelectronics, in particular by deep reactive ion etching (English-used by reactive-ion etching and with DRIE). The manufacturing process generally includes the following steps:

- providing a slab of micro-machinable material, such as silicon,

- form the timepiece component, by etching through the entire thickness of the plate,

- releasing the component by separating it from the rest of the plate.

[0003] l'use of materials and fabrication techniques from microelectronics offers very interesting, especially in terms of accuracy. Challenging is however release the component, without damage thereto. Generally, fasteners, or bridges of material, are provided between the timepiece component and the rest of the plate. These fasteners are responsible for maintaining the piece secured to the plate throughout the manufacturing of the component, especially during treatments applied to the component after etching (heat treatment, plating, and so on), while facilitating release of the component at the end of fabrication.

[0004] le document to the EP 2,145 857 describes a method of manufacturing a timepiece component similar to that described above. Bridges of material are etched and hold the component integral with the plate during the different steps of manufacturing the timepiece component. To facilitate the release of the component at the end of fabrication, the bridges have a narrowed section at the end connected to the component. This creates a zone of weakness facilitating breaking of the bridges of material. At the end of fabrication, the timepiece component is released from the plate by brittle fracture of the material at the fasteners, or bridges of material, in response to a mechanical stress adapted.

[0005] la breaks the material by brittle fracture between the cross piece and the component is hardly controllable.

[0006] le wo2013/093 108 the document describes a process for making a micromechanical component from a plate consisting of a micro-machinable material, fasteners being provided between the patch and the plate. These fasteners are locally weakened by thinning to create joints. These are adapted to allow detaching of the component by a torsional strain in the plane of the plate. This results in a break between the workpiece and the plate which lack of precision. The feed bars is not precisely determinable priori. It will be located along the tether weakened, without it being possible to know in advance whether it will be close to the work piece or plate. This may be annoying as functionally that beauty. In addition, to release the workpiece by twisting in the plane of the plate, must be in place around the part to allow relative movement of the plate and the workpiece. This causes to reduce the number of parts produced from a plate.

[0007] la present invention for improving the situation.

[0008] a therefor, a method of manufacturing a timepiece component comprising the following steps:

•providing a plate consisting of a micro-machinable material;

•form the timepiece component with at least one fastener holding the remainder of the plate, by etching the plate;

characterized in that it comprises a step of providing, along a line of desired breakage of the clip, a pre-spotter area having at least one opening obtained by etching through the thickness of the plate.

[0009] l'includes providing a pre-spotter area along a breaking line accurately determined. One or more openings are etched in the thickness of the plate to create a region of reduced mechanical strength, corresponding to the area pre-spotter, and initiate the breakage at the desired location, along the desired line of weakness.

[0010] le timepiece component can be obtained by etching the plate throughout its entire thickness. In other words, is etched in this case one or more through openings in the plate to form the component.

[0011] in a particular embodiment, said opening is obtained by etching a portion of the thickness of the plate.

[0012] according to a first embodiment, said opening extends along the entire line of the break.

[0013] according to a second embodiment, the pre-spotter area includes a plurality of apertures aligned along the line of weakness.

[0014] la length openings may be included for example between 2 and 10 MW.

[0015] en definitive, the area pre-spotter may include a single opening extending all along the break line, or more apertures aligned along the fracture line and separated by bridges. In any hypothesis, the fracture surface obtained after release of the timepiece component of the plate is much cleaner than the standard with a fastener. Further, reduces the risk of creating primers of crack in the component.

[0016] advantageously, the depth of the opening is less than or equal to 90% of the plate thickness, preferably less than or equal to 60% of said thickness.

[0017] advantageously still, the depth of the opening is greater than or equal to half the thickness of the plate.

[0018] la width of the openings may be between 1 and 10 MW, in particular between 1 and 5 MW.

[0019] in a particular embodiment, etching the etching the timepiece component and opening the area pre-spotter are carried out simultaneously.

[0020] in this case, the width of said zone opening pre-spotter is advantageously less than the width of an aperture therethrough for forming the timepiece component, in particular less than the smaller of the widths of a plurality of through openings forming the timepiece component

[0021] in a particular embodiment, the width of aperture therethrough for forming the component being greater than 40 MW, the width said area opening pre-spotter is between 1 and 10 MW, in particular between 1 and 5 MW.

[0022] such a width of the opening pre-spotter promotes detachment of the component caused by mechanical stress in a direction perpendicular to the plane of the plate, which is very simple and convenient to implement.

[0023] advantageously, etching the etching the timepiece component and opening the area pre-spotter are formed by deep reactive ion etching.

[0024] in another embodiment, the etching of the opening of the area pre-spotter and etching the timepiece component are carried out separately, respectively by means of femtosecond laser pulses and by deep reactive ion etching.

[0025] le material of the plate may be a brittle material, especially one of the materials of the group comprising silicon, diamond, quartz and ceramic.

[0026] advantageously, it comprises a step of releasing the timepiece component by breakage or rupture of the clip along the break line.

[0027] advantageously, during the step of releasing the timepiece component, is caused to break by exerting mechanical force on the fastener in a direction having an angle less than or equal to 45° relative to a direction perpendicular to the plate, in particular less than or equal to 30° relative to a direction perpendicular to the plate, preferably in a direction perpendicular, or substantially perpendicular, to the plate.

[0028] as a result, the release of the timepiece component is simple and convenient to implement. Further, it does not need to provide sufficient space around the components. It is therefore possible to optimize the use of the plate for making as many components as possible from it.

[0029] le timepiece component can be one of the elements of the group comprising a hairspring, a wheel, a needle, a spring, an anchor and a balance wheel.

[0030] l'also a plate of a micro-machinable material comprising a timepiece component and at least one fastener holding between the timepiece component and the rest of the plate, formed by openings etched into the thickness of the plate, characterized by the fact that it includes a pre-spotter of the timepiece component comprising, along a line of desired breakage of the clip, at least an opening etched in the thickness of the plate

[0031] l'aspect is a timepiece component in micro-machinable material comprising a breakaway region partially etched.

[0032] l'invention will be better understood with the aid of the following description of various exemplary embodiments of the method of manufacturing a timepiece component, of a plate of a micro-machinable material incorporating a timepiece component and a timepiece component according to the invention, with reference to the accompanying drawings on which:

the Figure. 1a, 1b and 1c are respectively a plan view and a sectional view (in the YZ plane) of a clip between a timepiece component and a plate of a micro-machinable material, and a view

partial of the timepiece component, of the plate and the fastener, according to a first embodiment;

figure 2 represents a view of a bridge of material between a timepiece component and a plate of a micro-machinable material, previous constructions;

figure 3 represents a plan view of a bridge of material between a timepiece component and a plate of a micro-machinable material, according to one embodiment similar to that of fig.. 1a and 1b;

figure 4 represents a top view of a bridge of material between a timepiece component and a plate of a micro-machinable material, according to a second embodiment;

figure 5 represents a top view of a bridge of material between a timepiece component and a plate of a micro-machinable material, according to a variant of the second embodiment;

the fig.. 6 represents a magnified view and partial area pre-spotter of a material bridge according to a variant of the second embodiment;

the Figure. 7a and 7b represent breakdown regions respectively of a timepiece component now and a timepiece component according to the first embodiment;

the fig.. 8 represents another illustrative example of a fractured surface obtained by implementing the method of the invention,

fig. 9 is a flow chart of steps in the manufacturing process, according to a particular embodiment;

the Figure. 10a to 10f represent a view of area detail pre-spotter of a fastener between a timepiece component and a plate of a micro-machinable material, according to a first embodiment (fig.. 10c and 10d), a second embodiment (10th and 10f) and according to another embodiment (10a and 10b).

[0033] en reference to the Figure. 9, the method of the invention comprises primarily four steps S1, S2 and, s3 s4 and bridges for producing a timepiece component 1 from a micro-machinable material.

[0034] by material "micro-machinable", is meant to designate any material suitable for micromachining. In accordance with the dictionary professional illustrated the timepiece fooled, the micromachining designates "the set of techniques from microelectronic (chemical attack, photolithography, thin film deposition vapor, and so on), plus other techniques capable of machining a wide range of materials such as semiconductors, ceramics, metals, certain polymers, and the like". The micro-machinable material used in the exemplary embodiments described below is silicon. Other materials could clearly be micro machinable used instead, such as the diamond, quartz and ceramic.

[0035] l ' s1 step includes the steps of providing a plate 2 of micro-machinable material, here a wafer (or "wafers") silicon, similar to those used for the production of microelectronic components. The wafer has for example a thickness of 150 MW. Of course, other thicknesses can be used for wafer.

[0036] l ' s2 step includes forming a timepiece component in the plate 1 and one or more fasteners for holding the component 3 1 the remainder of the plate 2. the timepiece component 1 and its attachment means 3 are performed simultaneously, respectively upon substeps referenced s20 ("DRIE_1") and ("DRIE_2") s21, by photolithography followed by a deep reactive ion etching. At those stages s20 and S21, the press plate 2, herein throughout its thickness, portions around the component 1 and fasteners 3. in other words, the press plate 2 a pattern of through openings, the shapes thereof being adapted for forming the component 1 and its attachment means 3.

[0037] en variant, to form the timepiece component, which could be used a plate formed of several layers, for example an SOI wafer formed of two Si layers sandwiching a layer of Si02 sandwitched, where one of the Si layers is used to form the component, and the other Si layer is used as the carrier. In such a case, the term "opening" an opening that passes through the entire Si layer in which is formed the component, and not an opening that extends through the entire plate itself.

[0038] le role fasteners 3 is to maintain the timepiece component 1 integral with the plate 2 during manufacturing and allow release of the timepiece component 1, by breaking the clip 3, at the end of fabrication. The fasteners 3 are bridges of material between the timepiece component etched 1 and the rest of the plate 2. they may take a variety of forms.

[0039] by definition, so-called "length" of a fastener, the size of the fastener along a longitudinal direction connecting the centroids of the two connection ends of the clip (respectively the remainder of the plate 2 and the component 1), in the plane of the plate 2 (c'est i.e. a plane parallel to the upper and lower surfaces of the plate, through which it extends). Similarly, called "width" the size of the clip in a direction perpendicular to the longitudinal direction. On the Figure. 1a and 1 b., the length of the clip 3 is the dimension along the Y axis and its width is the dimension along the X axis.

[0040] in the example embodiment shown in the Figure. 1a and 1 b., the width of the clip 3 continuously decreases from its attachment to the remainder of the plate 2 until at its end connecting timepiece component 1. Could however contemplated that other forms of attachment 3, particularly a clip of constant width, with optionally a cusp adjacent connection end component.

[0041] on the Figure. 1a, 1b and 1c, the timepiece component 1 represented is a hairspring (only half of the hairspring, from the center to the edge, being shown in Figure. 1b and 1c). Of course, the method of the invention applies to the manufacture of other components timekeeping. The timepiece component may be an entity useful for mounting in a movement (e.g. a needle, a spring, and so on) or a piece to be joined to one or more other components (e.g. a spiral to the balance axle, wheel to its axis, an anchor to the rod (or axis) anchor, a balancer to the balance staff, and so forth) before mounting.

[0042] l ' s3 step includes performing, for each clip 3, along a line of desired breakage of the clip 3, a pre-spotter area 4.

[0043] by "breaking line", is meant to designate a line in the plane of the plate along which material failure is desired upon release of the component 1 of the plate 2. the break line here comprises a straight section extending in the width direction of the clip 3 (c'est to say according to the X direction), and over the entire width of the clip 3, the connection end of the clip 3 to the component 1. Could obviously contemplated that other forms of break line and other locations (for example in the middle of the clip, or at the end of connection with the plate).

[0044] la area pre-spotter 4 extends along the break line, the connection end of the clip 3 at timepiece component 1, across the width of the clip 3 (the direction X in Figure. 1A). The length of the zone 4 pre-spotter, c'est i.e. its dimension along the break line (either in the X direction in fig. 1 has), is for example between 20 and 150 MW.

[0045] in the example embodiment shown in fig.. 1a and 1b, for performing the pre-spotter area 4, 5 an opening is etched which extends continuously along the entire line of weakness and thence through the clip 3 in the direction of its width. The opening 5 has the form of a trench extending in the X direction and having a U-shaped cross section right (Figure. 1B).

[0046] la depth of the trench 5 is for example equal to about 75% of the total thickness of the plate (or component) and its width (c'est i.e. its dimension in the Y direction) is for example of the order of 4 MW. The depth and width of the trench 5 could obviously have other values. For example, the depth may be greater than or equal to half the thickness of the plate (or component) and less than or equal to 90% of the thickness of the plate (or component), preferably less than or equal to 60% of said thickness. The width may be greater than or equal to 1 MW and 10 MW or less, preferably less than 5 MW.

[0047] la etching the timepiece component 1 ("DRIE_1") and the etching of the opening 5 ("DRIE_3") of the pre-spotter area 4 can be carried out simultaneously by deep reactive ion etching (with DRIE).

[0048] l'opening 5 creates in the clip 3, the connection end of the clip 3 to component 1, a region of reduced mechanical strength (c'est i.e. the area pre-spotter 4) and initiate the breakage at the desired location on the component 1.

[0049] l ' step comprises releasing the s4 timepiece component 1 of the plate 2, by breaking or broken fasteners 3 along their line of weakness. The break may be caused by exerting on the clip 3 mechanical force in a direction perpendicular, or substantially perpendicular, to the plane of the plate (corresponding to the Z direction on the Figure. 1a and 1b). By "substantially perpendicular", is meant to designate a direction having an angle of plus or minus 10° with respect to the direction perpendicular to the plate (or perpendicular to the plane of the plate). Alternatively, break is caused by exerting on the clip 3 mechanical force in a direction having an angle less than or equal to 45° relative to a direction perpendicular to the plate, in particular less than or equal to 30° relative to a direction perpendicular to the plate. The material of the plate 1 is a brittle material, not having domain of plastic deformation, the force applied perpendicular, or substantially perpendicular, or in a direction nearly perpendicular to the plate, has the effect of breaking the material at the area pre-spotter 4, along the line of weakness. Break is facilitated and controlled by the pre-stain release 4. also contemplated that could release the component 1 of the plate 2 by completing the etching of the clip at the area pre-spotter 4 by laser treatment, in particular with a femtosecond pulse laser equipment.

[0050] la breakage by mechanical stress in a direction perpendicular to the plane of the plate, i.e. by pulling or twisting along the direction Z, is simple to implement and favorable for making components, including spiral or wheels. Contrariwise, breakage by mechanical stress in a plane of the plate, i.e. by torsion along a direction contained in the X-Y plane, for example by accessing a joint, would not be practical to implement. Indeed, this would require providing room around the component to move the elements, this places cannot therefore not be used for the construction of other components.

[0051] le timepiece component released 1 has, on its edge, a fractured surface 100, as shown by way of illustrative example in Figure. 7B. This surface 100 has two discrete adjacent parts, one 102 etched and the other 101 broken. The portion 102 corresponds to one of the side walls of the U-shaped opening 5 etched, whereas the portion 101 corresponds to the bottom of the U broken. In Figure. 7a, for comparison purposes, is shown a fractured surface 100' obtained with a fastener now, without pre-spotter area 4. it appears that the fracture surface of the fig. 100. 7b is sharper, cleaner and less extensive that the fracture surface 100'.

[0052] on may consider different embodiments of the area pre-spotter 4. on the Figure. 3, 4 and 5, there is shown diagrammatically three examples of distinct embodiment. For clarity, the corresponding or like elements shown in different drawings bear the same references.

[0053] in Figure. 3, the area pre-spotter 4 comprises an opening 5 in the form of a trench that extends to the connecting end of the clip 3 to component 1, across the width of the clip 3, along a straight line of weakness. It is an embodiment similar to that of fig.. 1a and 1b.

[0054] Figures 4 and 5 on the, the area pre-spotter 4 comprises a plurality of openings etched 5 aligned along the break line (the latter not being shown for clarity, but is similar to that of Figure 3) separated by bridges and un-etched. The bridges and the openings 5 are here of the same length. They could clearly be of different lengths. The openings 5 are cuboid in shape. They can pocket, c'est to say etched into a portion of the thickness of the plate, or through perforations, c'est to say etched into the full thickness of the plate. The embodiments of Figures 4 and 5 differ in the size of the openings on the fig. 5.. 4, 5 the openings have a width (according to the Y-direction) of 2 PM and a length (the direction X) of 10 MW. In Figure. 5, 5 the openings have a width (according to the Y-direction) of 2 PM and a length (in the X direction) of 2 MW. Of course, the dimensions and shapes of the openings 5 could be different. The dimensions of the openings 5 aligned along the line of weakness may for example be as follows:

- length (along the break line) between 2 PM and 10 MW;

- width between 1 PM and 5 MW;

- depth not less than half the thickness of the plate.

[0055] in Figure. 8, is shown, by way of illustrative example, a breakaway region 100 obtained with an area pre-spotter 4 5 having a plurality of apertures arrayed along a fracture line and having the following characteristics:

3 - width of the clip to the attachment end of the component 1 of 100um,

- width openings pre-spotter 5 of 4 MW;

- length of the apertures pre-spotter 5 of 2 MW;

- gap openings of 2 MW;

depth of the holes - 5 equal to about 80% of the total thickness of the plate.

[0056] in this case, the rupture zone 100 comprises a broken portion 101 (c'est i.e. a fracture surface obtained by breaking the material) and a portion 102 having an alternating sequence of etched grooves and grooves broken, arranged vertically. The two parts 101 and 102 are arranged one below the other according to the thickness of the component 1. note that in Figure. 8, the boundary between the ruptured portion 101 and the grooved portion 102 is curved because the etch rate is not equal throughout the length of the break line, the areas near the ends of the tear line being etched more rapidly than the center.

[0057] in the above description, the timepiece component 1 and the opening or openings 5 are etched at the same time. Alternatively, the etching of the opening 5 and that of the timepiece component 1 can be performed separately. In this case, the apertures can be made by various ablation techniques, for example by DRIE, by ablation using femtosecond pulses emitted by laser equipment, by mechanical ablation (diamond saw), or the like. Preferably, the timepiece component 1 and the opening or openings 5 are etched at the same time.

[0058] for etching separately the timepiece component 1 and the opening (or openings) 5 of the area pre-spotter, there may be two masking steps. In this case, a first masking step is performed to etch the at least one opening region 5 pre-spotter 4. a second masking step is then performed to etch the timepiece component 1 and its attachment means 3, while protecting the opening or openings 5. could also be considered to reverse, c'est i.e. make a first mask to etch the through openings to form the component and its attachment means 3 1 clockwork, and then a second mask for etching the at least one opening pre-spotter 5 while protecting the through openings. The masking may include masking mechanical or a masking formed by photolithography with photoresist.

[0059] in the case of a simultaneous etching of the timepiece component 1 and the aperture 5 pre-spotter, the depth of the opening (O) 5 depends on a variety of parameters related to the etching of the timepiece component, especially the etch rate of the DRIE and the duration of the attack. Further, the depth of the opening (O) 5 is also dependent upon the width and length of said aperture or apertures (e) 5. in any hypothesis, in this case, the driving period by the writer is the same for carrying out both the apertures for forming the component and the at least one opening (e) pre-spotter 5, simultaneously. It is therefore preferred that the width of the openings 5 pre-spotter is less than the width of the through-openings forming the timepiece component, or, in the case where the through-openings forming the timepiece component have different widths from each other, smaller than the smallest of the widths of the openings forming the timepiece component. In particular, if the width of the through-openings forming the component is greater than 40 MW, and/or is contained within a value range between 40 and 100 MW MW, or is greater than 100 MW, the width of the openings 5 pre-spotter will advantageously be between 1 and 10 MW, or even between 1 and 5 MW. Thus, in the case where the through openings for forming the timepiece component and the at least one opening (e) pre-spotter are performed simultaneously, the selected width for the at least one opening (e) pre-spotter 5 according to the invention ultimately depends on the smallest one of the widths of the openings forming the timepiece component and the desired depth for the at least one opening (e) pre-spotter. In addition, the width of the opening (e) pre-spotter may depend on features of the method and/or device of the DRIE used. Those skilled in the know perform the test adjustment needed for determining the optimal width openings pre-spotter 5.

[0060] le method may also include the additional steps of treatment, performed before or after releasing the component, such as thinning of previously plate micro-machinable material (to reduce its thickness), a coating deposition, oxidizing heat treatment, a cleaning/degreasing, andc.

[0061] on now describe various forms or embodiments of the area pre-spotter with reference to the Figure. 10a to 10f. On these drawings, the break line along which extends the area pre-spotter is noted "I".

[0062] in the case of a pre-spotter area having a continuous opening 5, of the type shown lesfig. 1a and 1 b., etching an opening could be pre-spotter 5 variable width along the break line. In this case, this varies the also the depth of the opening along the break line, noted the L, as shown in Figure. 10a and 10b, which respectively represent a top view of a fastener 3 between the plate 2 and the component 1 and a zoomed view on the plane defined by the X and Z axes, the opening pre-spotter 5.

[0063] a comparison as the Figure. 10c and 10d respectively represent a top view of a fastener 3 between the plate 2 and the component 1 and a zoomed view on the plane defined by the X and Z axes of the opening pre-spotter 5, according to the first embodiment wherein the width and depth of the opening pre-spotter 5 are constant along the break line L-.

[0064] the Figure. 10th and 10f respectively represent a top view of a fastener 3 between the plate 2 and the component 1 and a zoomed view on the plane defined by the X and Z axes, the opening pre-spotter 5, according to the second embodiment wherein the area pre-spotter includes a plurality of apertures aligned along the break line L-.

[0065] la presence of a rupture line is advantageous because it is possible to precisely determine the location and extent of the fracture surface. This is not the case when using a known technique of prior consisting, for example, providing a single bridge of material or a material bridge of lesser width and/or of lesser thickness. In this case, the feed bars is not precisely determined. It may reside somewhere along the weakened material bridge, and can both be proximate to the component that the remainder of the plate. This results in uncertainty on locating the break. In addition, in some cases, the breakage degrades the beauty of the component, or even its operability, and this feature is particularly undesirable.

[0066] l'invention also relates to a timepiece component having a predetermined breaking point partially etched. By "breaking zone", is meant to designate the portion of the slice of the component (throughout the thickness of the component) containing one or more fracture surfaces. According to the embodiment of the inventive method, the rupture zone may include:

- a fully etched and a portion fully broken arranged one above the other (according to the thickness of the component);

- a portion having an alternating sequence of etched grooves and grooves broken, and a part fully broken, arranged one above the other (according to the thickness of the component);

- an alternate succession of etched grooves and grooves broken (throughout the thickness of the component).