EP4312084A1 - Method for manufacturing a silicon hairspring - Google Patents
Method for manufacturing a silicon hairspring Download PDFInfo
- Publication number
- EP4312084A1 EP4312084A1 EP22187006.6A EP22187006A EP4312084A1 EP 4312084 A1 EP4312084 A1 EP 4312084A1 EP 22187006 A EP22187006 A EP 22187006A EP 4312084 A1 EP4312084 A1 EP 4312084A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- silicon
- watch component
- handle
- component
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 62
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 50
- 239000010703 silicon Substances 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 31
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 30
- 238000000708 deep reactive-ion etching Methods 0.000 claims description 20
- 238000005530 etching Methods 0.000 claims description 19
- 238000004873 anchoring Methods 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 11
- 238000005034 decoration Methods 0.000 claims description 7
- 238000001039 wet etching Methods 0.000 claims description 5
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims description 3
- 230000000284 resting effect Effects 0.000 claims description 3
- 230000002747 voluntary effect Effects 0.000 claims description 3
- 210000003477 cochlea Anatomy 0.000 claims description 2
- 235000012431 wafers Nutrition 0.000 description 31
- 239000011347 resin Substances 0.000 description 16
- 229920005989 resin Polymers 0.000 description 16
- 239000000758 substrate Substances 0.000 description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 239000012212 insulator Substances 0.000 description 4
- 239000002210 silicon-based material Substances 0.000 description 4
- 230000008021 deposition Effects 0.000 description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 241000237858 Gastropoda Species 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011195 cermet Substances 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G04—HOROLOGY
- G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
- G04B17/00—Mechanisms for stabilising frequency
- G04B17/04—Oscillators acting by spring tension
- G04B17/06—Oscillators with hairsprings, e.g. balance
- G04B17/066—Manufacture of the spiral spring
-
- G—PHYSICS
- G04—HOROLOGY
- G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
- G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
- G04D3/0069—Watchmakers' or watch-repairers' machines or tools for working materials for working with non-mechanical means, e.g. chemical, electrochemical, metallising, vapourising; with electron beams, laser beams
-
- G—PHYSICS
- G04—HOROLOGY
- G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
- G04B13/00—Gearwork
- G04B13/02—Wheels; Pinions; Spindles; Pivots
-
- G—PHYSICS
- G04—HOROLOGY
- G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
- G04B19/00—Indicating the time by visual means
- G04B19/04—Hands; Discs with a single mark or the like
- G04B19/042—Construction and manufacture of the hands; arrangements for increasing reading accuracy
-
- G—PHYSICS
- G04—HOROLOGY
- G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
- G04B19/00—Indicating the time by visual means
- G04B19/06—Dials
- G04B19/10—Ornamental shape of the graduations or the surface of the dial; Attachment of the graduations to the dial
- G04B19/103—Ornamental shape of the graduations or the surface of the dial; Attachment of the graduations to the dial attached or inlaid numbers
-
- G—PHYSICS
- G04—HOROLOGY
- G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
- G04B21/00—Indicating the time by acoustic means
- G04B21/02—Regular striking mechanisms giving the full hour, half hour or quarter hour
- G04B21/04—Hour wheels; Racks or rakes; Snails or similar control mechanisms
-
- G—PHYSICS
- G04—HOROLOGY
- G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
- G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
- G04D3/0074—Watchmakers' or watch-repairers' machines or tools for working materials for treatment of the material, e.g. surface treatment
Definitions
- the invention relates to a method of manufacturing a silicon watch component, and more specifically a silicon watch component having a functional external profile.
- Silicon watch components are generally manufactured by deep reactive ion etching - a technique also known by the English abbreviation DRIE - of a wafer of silicon-based material.
- the wafer can be a silicon wafer which is etched throughout its thickness (see for example the patent applications EP 1722281 , EP 2145857 And EP 3181938 ) or a silicon on insulator substrate called SOI (silicon on insulator) comprising an upper layer of silicon and a lower layer of silicon bonded by an intermediate layer of silicon oxide, the upper layer of silicon being that in which the etching is carried out (see for example patent applications WO 2019/180177 And WO 2019/180596 ).
- the silicon-on-insulator substrate has the advantage of having a rigid support (the lower layer of silicon, of greater thickness than the upper layer) facilitating its handling and its maintenance and a layer of stop (the intermediate layer of silicon oxide) allowing the etching to be stopped.
- Such fasteners which connect the periphery of each component to the wafer, can pose a problem, particularly when the periphery of the component is a functional surface which must not have its function disrupted by attachment residues or when the external surface of the component must present a particularly neat appearance, as for example in the case of a needle.
- the functional exterior surface does not have free space of sufficient size to be able to insert a sufficiently robust fastener.
- the patent application WO 2019/166922 proposes a process for manufacturing a watch hairspring according to which a silicon substrate carrying a silicon oxide layer is provided, through holes are formed in the silicon oxide layer, a layer of silicon on the layer of silicon oxide, this layer of silicon filling the through holes to form attachments or bridges of material, spirals are etched into the layer of silicon, the layer of silicon oxide is eliminated, the spirals remaining attached to the silicon substrate by said fasteners, the spirals are subjected to heat treatments and finally the spirals are detached from the silicon substrate.
- the hairsprings remain linked to the substrate after etching by attachments extending outside the plane of the hairsprings rather than between the exterior surface of the last turn and the etching silicon layer as is generally the case.
- this process does not allow the use of commercial silicon-on-insulator substrates, and growing the silicon layer in which the hairsprings will be formed by epitaxy is a complicated operation.
- the patent application WO 2019/166922 aims to resolve this problem and proposes a process for manufacturing a silicon watch component from an SOI wafer in which the component is attached to an internal anchor to the contour of the component.
- the fastener does not encroach on the functional external contour of the component.
- this process does not does not allow work on the rear face of the component, particularly for components requiring surface treatment or even decoration.
- the invention resolves the aforementioned drawbacks by proposing a solution making it possible to keep the components attached to the wafer, including those which do not allow an attachment to be provided on their external contour, while freeing the rear face to be able to work on it and/or decorate it. .
- the invention also relates to a watch component obtained by implementing a process for manufacturing a watch component conforming to the invention.
- the invention relates to a method of manufacturing a silicon watch component, and more particularly a silicon watch component whose external profile is functional.
- functional external profile is meant a watch component whose outer periphery of the component forms a functional surface arranged to cooperate with other watch parts and/or components.
- the silicon-based material used may be monocrystalline silicon whatever its crystalline orientation.
- other compounds based on silicon or other materials can be considered such as glass, ceramic, cermet, metal or metal alloy.
- the explanation below will be based on a silicon-based material.
- the invention relates to a method of manufacturing a silicon watch component 1.
- Other watch components can be manufactured via the method according to the invention, such as a toothed wheel, an escape wheel, a seesaw, a snail, etc.
- Such a process can also be considered for the manufacture of hands, indexes or even appliques which require the most careful possible external surface finish.
- the method comprises, as illustrated in figure 2 , a first step a) which consists of providing SOI wafers 10, that is to say composed of two layers of silicon 11 and 12, linked to each other by a layer of silicon oxide 13 Each of these three layers has one or more specific roles.
- the lower layer of silicon 12, called “handle”, essentially serves as a mechanical support, so as to be able to carry out the process on a sufficiently rigid assembly (which the reduced thickness of the "device” is not able to guarantee) . It is also made up of a monocrystalline silicon plate, generally of a similar orientation to the "device" layer.
- the oxide layer 13 makes it possible to intimately bond the two silicon layers 11 and 12. In addition, it will also serve as a stopping layer during subsequent operations.
- the following step b) consists of growing a layer of silicon oxide on the surface of the wafer(s) 10, by exposing the wafer(s) to an oxidizing atmosphere at high temperature.
- the layer varies depending on the thickness of the “device” to be structured. It is typically between 1 and 4 ⁇ m. Of course other techniques can be used, to form an etching mask, a layer of resin, as in the following step c), can be sufficient, and if oxide is used, this can be deposited and not raw.
- step c) the exposed areas or, on the contrary, covered with resin are then exploited.
- a first etching process makes it possible to transfer the patterns defined in the resin in the previous stages into the previously raw silicon oxide.
- the silicon oxide is structured by dry plasma etching, directional and reproducing the quality of the sides of the resin serving as a mask for this operation.
- the silicon oxide is etched into the open areas of the resin, the silicon surface of the upper layer 11 is then exposed and ready for DRIE etching.
- the resin can be kept or not depending on whether you want to use the resin as an additional mask during DRIE etching.
- the silicon exposed and not protected by silicon oxide is etched in a direction perpendicular to the surface of the wafer (DRIE Bosch ® anisotropic etching).
- the patterns formed first in the resin, then in the silicon oxide, are "projected” into the thickness of the "device” layer 11.
- the etching leads to the silicon oxide layer 13 linking the two silicon layers 11 and 12, the etching stops. Indeed, like the silicon oxide serving as a mask during the Bosch ® process and resisting the etching itself, the buried oxide layer 13, of the same nature, also resists it.
- the silicon layer "device” 11 is then structured throughout its thickness by the defined patterns representing the components to be manufactured, now revealed by this DRIE engraving, namely a cam 1 in the example illustrated.
- step c) part of the upper silicon layer 2 is etched so as to form an internal anchoring element to the watch component, as well as a material bridge 8 connecting this anchoring element 7 to the internal wall of the watch component 1, in a non-critical zone of the internal wall of the component.
- the internal wall of the watch component is the wall of a hole arranged to receive an axis.
- the hole, shaped, allows the attachment residue not to interfere with the shaft cooperating with the silicon board.
- the internal wall could be another internal opening to the component, for example if it is skeletonized.
- step c) the process cannot be limited to DRIE etching during step c).
- the etching of step c) could just as easily be obtained by chemical etching in the same silicon-based material.
- step c several cams can be formed in the same wafer.
- step d a second photolithography operation similar to the first carried out during step c) is carried out on the back of the wafer 10 (therefore “handle” layer side 12).
- the wafer 10 is turned over, the resin is deposited there, then exposed through a mask.
- this second photolithography operation at least one narrow bridge 9 is formed across the rear of the watch component as well as a rear anchor 9' secured to the at least one narrow bridge 9, the rear anchor 9 ' being connected to the anchoring element 7 of the "device” layer by the silicon oxide layer linking the "device” layer and the "handle” layer.
- an integrated shadow mask is also formed during the DRIE etching of the “handle” layer during step d), so as to produce a deliberate and voluntary pattern of openings on the rear face, said openings allowing then to create a decoration elaborated by CVD or PVD deposition during a subsequent step.
- the area of exposed resin is then removed using a solvent, revealing the oxide layer previously formed and serving as a mask for deep dry etching, such as DRIE etching, which makes it possible to reveal the at least a narrow deck 9, the rear anchor 9' and the shadow mask.
- a solvent such as DRIE etching
- step e) to completely release the components the various layers of silicon oxide are then etched by means of wet etching with a solution based on hydrofluoric acid or even by hydrofluoric acid in vapor phase.
- the cams 1 formed are held to the anchoring element via the bridge of material 8, and the whole resting on the rear anchor connected to the at least one narrow bridge itself connected to a frame formed in the “handle” layer.
- step f) consists of subjecting various surface termination operations to the part released and still held by the fastener.
- the finishing stage may consist of depositing layers, structuring or decoration on the different faces of the watch component. These operations are functional (reinforcement, tribological, etc.) or aesthetic (coloring, pattern), by PVD or CVD.
- step d) the pattern developed during step d) via the shadow mask is also decorated via CVD or PVD deposits
- cam 1 as illustrated in figures 1a and 1b which, advantageously according to the invention, comprises a core based on silicon and a coating based on silicon oxide.
- the method can also include step h) intended to separate the watch component 1 from the wafer 10 by separating the component 1 from its anchoring element 8.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Optics & Photonics (AREA)
- Plasma & Fusion (AREA)
- Micromachines (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Weting (AREA)
Abstract
L'invention concerne un procédé de fabrication d'une composant horloger (1) en silicium présentant un profil externe fonctionnel.The invention relates to a method for manufacturing a silicon watch component (1) having a functional external profile.
Description
L'invention se rapporte à un procédé de fabrication d'un composant horloger en silicium, et plus précisément d'un composant horloger en silicium présentant un profil externe fonctionnel.The invention relates to a method of manufacturing a silicon watch component, and more specifically a silicon watch component having a functional external profile.
Les composants horlogers en silicium sont généralement fabriqués par gravure ionique réactive profonde - technique également connue sous l'abréviation anglaise DRIE - d'une plaquette de matériau à base de silicium. La plaquette peut être une plaquette de silicium que l'on grave dans toute son épaisseur (cf. par exemple les demandes de brevet
Quel que soit le type de plaquette utilisé, plusieurs composants sont gravés simultanément dans la même plaquette et des attaches ou ponts laissés pendant la gravure maintiennent les composants attachés à la plaquette pour d'autres étapes de la fabrication. Les composants sont ensuite libérés de la plaquette par rupture ou élimination des attaches.Regardless of the type of wafer used, multiple components are etched simultaneously into the same wafer and clips or bridges left during etching keep the components attached to the wafer for further steps in fabrication. The components are then released from the board by breaking or removing the fasteners.
De telles attaches, qui relient la périphérie de chaque composant à la plaquette, peuvent poser problème, notamment lorsque la périphérie du composant est une surface fonctionnelle qui ne doit pas voir sa fonction perturbée par des résidus d'attache ou lorsque la surface externe du composant doit présenter un aspect particulièrement soigné, comme par exemple dans le cas d'une aiguille. Dans certains cas, également, en particulier pour des composants portant une micro-denture, la surface extérieure fonctionnelle ne présente pas d'espace libre de taille suffisante pour pouvoir y insérer une attache suffisamment robuste.Such fasteners, which connect the periphery of each component to the wafer, can pose a problem, particularly when the periphery of the component is a functional surface which must not have its function disrupted by attachment residues or when the external surface of the component must present a particularly neat appearance, as for example in the case of a needle. In certain cases, also, in particular for components carrying micro-teeth, the functional exterior surface does not have free space of sufficient size to be able to insert a sufficiently robust fastener.
La demande de brevet
Avec un tel procédé, les spiraux restent liés au substrat après la gravure par des attaches s'étendant hors du plan des spiraux plutôt qu'entre la surface extérieure de la dernière spire et la couche de silicium de gravure comme cela est généralement le cas. Cependant, ce procédé ne permet pas l'emploi de substrats silicium sur isolant du commerce, et faire croître par épitaxie la couche de silicium dans laquelle seront formés les spiraux est une opération compliquée.With such a process, the hairsprings remain linked to the substrate after etching by attachments extending outside the plane of the hairsprings rather than between the exterior surface of the last turn and the etching silicon layer as is generally the case. However, this process does not allow the use of commercial silicon-on-insulator substrates, and growing the silicon layer in which the hairsprings will be formed by epitaxy is a complicated operation.
La demande de brevet
L'invention résout les inconvénients précités en proposant une solution permettant de garder les composants attachés au wafer, y compris ceux ne permettant pas de ménager une attache sur leur contour externe, tout en dégageant la face arrière pour pouvoir la travailler et/ou la décorer.The invention resolves the aforementioned drawbacks by proposing a solution making it possible to keep the components attached to the wafer, including those which do not allow an attachment to be provided on their external contour, while freeing the rear face to be able to work on it and/or decorate it. .
A cet effet, la présente invention concerne un procédé de fabrication d'un composant horloger en silicium comprenant des étapes suivantes :
- a) se munir d'un wafer SOI comprenant successivement une couche de silicium dite « device », une couche de liaison en oxyde de silicium, et une couche de silicium dite « handle » ;
- b) faire croître une couche d'oxyde de silicium à la surface du wafer ;
- c) graver la couche d'oxyde de silicium (masque de gravure) en face, puis la couche « device » par DRIE, pour former le composant horloger en silicium ainsi qu'un élément d'ancrage interne et un pont de matière reliant ledit élément d'ancrage à une paroi interne du composant horloger dans une zone du contour intérieur non critique;
- d) graver la couche d'oxyde de silicium (masque de gravure) en face arrière, puis la couche « handle » par DRIE, pour former au moins un pont étroit ainsi qu'au moins un ancrage arrière solidaire de l'au moins un pont étroit, l'ancrage arrière étant relié à l'élément d'ancrage de la couche « device » par la couche d'oxyde de silicium liant « device » et « handle »;
- e) libérer le composant horloger par le biais d'une gravure humide, le composant horloger étant maintenu au wafer par l'élément d'ancrage via le pont de matière, la couche d'oxyde de liaison n'étant plus présente que là où et la couche « device » et la couche « handle » n'ont pas été attaquées par la gravure humide, le tout reposant sur l'au moins un ancrage arrière relié à l'au moins un pont étroit lui-même relié à la couche « handle ».
- a) equip yourself with an SOI wafer successively comprising a layer of silicon called a “device”, a bonding layer of silicon oxide, and a layer of silicon called a “handle”;
- b) growing a layer of silicon oxide on the surface of the wafer;
- c) etch the silicon oxide layer (engraving mask) opposite, then the “device” layer by DRIE, to form the silicon watch component as well as an internal anchoring element and a material bridge connecting said anchoring element to an internal wall of the watch component in a non-critical area of the internal contour;
- d) etch the silicon oxide layer (etching mask) on the rear face, then the “handle” layer by DRIE, to form at least one narrow bridge as well as at least one rear anchor secured to the at least one narrow bridge, the rear anchor being connected to the anchor element of the “device” layer by the layer of silicon oxide binding “device” and “handle”;
- e) releasing the watch component by means of wet etching, the watch component being held to the wafer by the anchoring element via the material bridge, the bonding oxide layer being only present where and the “device” layer and the “handle” layer have not been attacked by wet etching, the whole resting on the at least one rear anchor connected to the at least one narrow bridge itself connected to the layer “handle”.
Conformément à d'autres variantes avantageuses de l'invention :
- la paroi interne du composant horloger est la paroi d'un trou agencé pour recevoir un axe ou une ouverture interne au composant ;
- la couche de liaison en oxyde de silicium est partiellement présente entre l'élément d'ancrage et l'ancrage arrière à la fin de l'étape e) ;
- le pont étroit et le pont de matière ne sont pas superposés ;
- au cours de l'étape d), on forme également un shadow mask intégré lors de la gravure DRIE de la couche « handle » de manière à réaliser un motif délibéré et volontaire d'ouvertures en face arrière, lesdites ouvertures permettant un décor élaboré par dépôt CVD ou PVD ;
- le procédé comprend une étape f) de finition en wafer des faces avant et/ou arrière du composant horloger, l"étape de finition consistant en un dépôt de couches, de structuration et/ou de décoration par exemple ;
- le composant horloger est une roue, une came, une aiguille, une bascule, un limaçon, un index ou une applique.
- the internal wall of the watch component is the wall of a hole arranged to receive an axis or an internal opening in the component;
- the silicon oxide bonding layer is partially present between the anchoring element and the rear anchoring at the end of step e);
- the narrow bridge and the material bridge are not superimposed;
- during step d), an integrated shadow mask is also formed during the DRIE engraving of the “handle” layer so as to produce a deliberate and voluntary pattern of openings on the rear face, said openings allowing a decoration developed by CVD or PVD deposition;
- the method comprises a step f) of finishing in wafer the front and/or rear faces of the watch component, the finishing step consisting of a deposition of layers, structuring and/or decoration for example;
- the watch component is a wheel, a cam, a hand, a rocker, a cochlea, an index or an applique.
L'invention concerne également un composant horloger obtenu par la mise en oeuvre d'un procédé de fabrication d'un composant horloger conforme à l'invention.The invention also relates to a watch component obtained by implementing a process for manufacturing a watch component conforming to the invention.
On comprend donc que le procédé permet d'avoir accès à la face arrière des composants horlogers attachés au wafer pour pouvoir la travailler et/ou la décorer.We therefore understand that the process allows access to the rear face of the watch components attached to the wafer in order to be able to work on it and/or decorate it.
D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description détaillée suivante donnée à titre d'exemple nullement limitatif, en référence aux dessins annexés dans lesquels :
- les
figures 1a et 1b représentent respectivement une vue en perspective d'un composant en silicium solidaire de la couche « device » et une vue en perspective de la couche « handle »; - les
figures 2a et 2b représentent respectivement une vue en perspective de dessus et de dessous d'un composant en silicium formé dans un wafer SOI.
- THE
figures 1a and 1b respectively represent a perspective view of a silicon component integral with the “device” layer and a perspective view of the “handle” layer; - THE
figures 2a and 2b respectively represent a top and bottom perspective view of a silicon component formed in an SOI wafer.
L'invention se rapporte à un procédé de fabrication d'un composant horloger en silicium, et plus particulièrement un composant horloger en silicium dont le profil externe est fonctionnel.The invention relates to a method of manufacturing a silicon watch component, and more particularly a silicon watch component whose external profile is functional.
Par profil externe fonctionnel, on entend un composant horloger dont le pourtour extérieur du composant forme une surface fonctionnelle agencée pour coopérer avec d'autres pièces et/ou composants horlogers.By functional external profile is meant a watch component whose outer periphery of the component forms a functional surface arranged to cooperate with other watch parts and/or components.
L'utilisation d'un matériau, à base de silicium, pour la fabrication d'un composant horloger offre l'avantage d'être précis par les méthodes de gravage existantes et de posséder de bonnes propriétés mécaniques et chimiques en étant notamment peu ou pas sensible aux champs magnétiques.The use of a material, based on silicon, for the manufacture of a watch component offers the advantage of being precise using existing engraving methods and of having good mechanical properties and chemical by being in particular little or not sensitive to magnetic fields.
Préférentiellement, le matériau à base de silicium utilisé peut être du silicium monocristallin quelle que soit son orientation cristalline. Bien entendu d'autres composés à base de silicium ou d'autres matériaux peuvent être envisagés comme un verre, une céramique, un cermet, un métal ou un alliage métallique. Par simplification, l'explication ci-dessous sera portée sur un matériau à base de silicium.Preferably, the silicon-based material used may be monocrystalline silicon whatever its crystalline orientation. Of course other compounds based on silicon or other materials can be considered such as glass, ceramic, cermet, metal or metal alloy. For simplification, the explanation below will be based on a silicon-based material.
Ainsi, l'invention se rapporte à un procédé de fabrication d'un composant horloger silicium 1. D'autres composants horlogers peuvent être fabriqués via le procédé selon l'invention, tels qu'une roue dentée, une roue d'échappement, une bascule, un limaçon, etc ... Un tel procédé peut également être envisagé pour la fabrication d'aiguilles, d'index ou encore d'appliques qui nécessitent un état de surface extérieur le plus soigné possible.Thus, the invention relates to a method of manufacturing a silicon watch component 1. Other watch components can be manufactured via the method according to the invention, such as a toothed wheel, an escape wheel, a seesaw, a snail, etc. Such a process can also be considered for the manufacture of hands, indexes or even appliques which require the most careful possible external surface finish.
Selon l'invention, le procédé comporte, comme illustré à la
La couche supérieure de silicium 11, nommée "device" et formée dans une plaque de silicium monocristallin (dont les orientations principales peuvent être variées), comporte une épaisseur qui va déterminer l'épaisseur finale du composant à fabriquer, typiquement, en horlogerie, entre 100 et 200µm.The upper layer of
La couche inférieure de silicium 12, nommée "handle", sert essentiellement de support mécanique, de façon à pouvoir effectuer le procédé sur un ensemble suffisamment rigide (ce que l'épaisseur réduite du "device" n'est pas en mesure de garantir). Elle est également formée d'une plaque de silicium monocristallin, en général d'une orientation similaire à la couche "device".The lower layer of
La couche d'oxyde 13 permet de lier intimement les deux couches de silicium 11 et 12. En outre, elle va également servir de couche d'arrêt lors d'opérations ultérieures.The oxide layer 13 makes it possible to intimately bond the two
L'étape b) qui suit consiste à faire croître à la surface du ou des wafers 10 une couche d'oxyde de silicium, en exposant le ou les wafers à une atmosphère oxydante à haute température. La couche varie selon l'épaisseur du « device » à structurer. Elle se situe typiquement entre 1 et 4µm. Bien entendu d'autres techniques peuvent être utilisées, pour former un masque de gravure, une couche de résine, comme à l'étape suivante c), peut suffire, et que si on utilise de l'oxyde, celui-ci peut être déposé et non crû.The following step b) consists of growing a layer of silicon oxide on the surface of the wafer(s) 10, by exposing the wafer(s) to an oxidizing atmosphere at high temperature. The layer varies depending on the thickness of the “device” to be structured. It is typically between 1 and 4µm. Of course other techniques can be used, to form an etching mask, a layer of resin, as in the following step c), can be sufficient, and if oxide is used, this can be deposited and not raw.
L'étape c) du procédé, va permettre de définir, par exemple dans une résine positive, les motifs que l'on souhaite réaliser par la suite dans le wafer 10 en silicium. Cette étape comprend les opérations suivantes :
- la résine est déposée, par exemple à la tournette, en une couche très mince d'épaisseur typiquement comprise entre 1 et 2µm,
- une fois séchée, cette résine, aux propriétés photolithographiques, est exposée à travers un masque photolithographique (plaque transparente recouverte d'une couche de chrome, elle-même représentant les motifs souhaités) à l'aide d'une source lumineuse ;
- dans le cas précis d'une résine positive, les zones exposées de la résine sont ensuite éliminées au moyen d'un solvant, révélant alors la couche d'oxyde. En l'occurrence, les zones toujours recouvertes de résine définissent les zones que l'on ne souhaite pas voir attaquées dans l'opération ultérieure de gravage ionique réactif profond (également connu sous l'abréviation « D.R.I.E. ») du silicium.
- the resin is deposited, for example by spinning, in a very thin layer with a thickness typically between 1 and 2 μm,
- once dried, this resin, with photolithographic properties, is exposed through a photolithographic mask (transparent plate covered with a layer of chrome, itself representing the desired patterns) using a light source;
- In the specific case of a positive resin, the exposed areas of the resin are then removed using a solvent, revealing the oxide layer. In this case, the areas still covered with resin define the areas that we do not want to see attacked in the subsequent operation of deep reactive ion etching (also known as “DRIE”) of silicon.
Au cours de l'étape c), on exploite alors les zones exposées ou au contraire recouvertes de résine. Un premier processus de gravure permet de transférer dans l'oxyde de silicium préalablement crû, les motifs définis dans la résine aux étapes précédentes. Toujours dans une optique de répétabilité du processus de fabrication, l'oxyde de silicium est structuré par une gravure sèche par plasma, directionnelle et reproduisant la qualité des flancs de la résine servant de masque pour cette opération.During step c), the exposed areas or, on the contrary, covered with resin are then exploited. A first etching process makes it possible to transfer the patterns defined in the resin in the previous stages into the previously raw silicon oxide. Still with a view to repeatability of the manufacturing process, the silicon oxide is structured by dry plasma etching, directional and reproducing the quality of the sides of the resin serving as a mask for this operation.
Une fois l'oxyde de silicium gravé dans les zones ouvertes de la résine, la surface de silicium de la couche supérieure 11 est alors exposée et prête pour une gravure DRIE. La résine peut être conservée ou non selon qu'on souhaite employer la résine comme masque supplémentaire lors de la gravure DRIE.Once the silicon oxide is etched into the open areas of the resin, the silicon surface of the
Le silicium exposé et non protégé par l'oxyde de silicium est gravé selon une direction perpendiculaire à la surface du wafer (gravure anisotrope DRIE Bosch®). Les motifs formés d'abord dans la résine, puis dans l'oxyde de silicium, sont "projetés" dans l'épaisseur de la couche "device" 11.The silicon exposed and not protected by silicon oxide is etched in a direction perpendicular to the surface of the wafer (DRIE Bosch ® anisotropic etching). The patterns formed first in the resin, then in the silicon oxide, are "projected" into the thickness of the "device"
Lorsque la gravure débouche sur la couche d'oxyde de silicium 13 liant les deux couches de silicium 11 et 12, la gravure s'arrête. En effet, à l'instar de l'oxyde de silicium servant de masque lors du processus Bosch® et résistant à la gravure elle-même, la couche d'oxyde enterrée 13, de même nature, y résiste également.When the etching leads to the silicon oxide layer 13 linking the two
La couche de silicium "device" 11 est alors structurée dans toute son épaisseur par les motifs définis représentant les composants à fabriquer, maintenant révélés par cette gravure DRIE à savoir une came 1 dans l'exemple illustré.The silicon layer "device" 11 is then structured throughout its thickness by the defined patterns representing the components to be manufactured, now revealed by this DRIE engraving, namely a cam 1 in the example illustrated.
Les composants restent solidaires de la couche "handle" 12 à laquelle ils sont liés par la couche d'oxyde de silicium enterrée 13. Au cours de cette étape c), une partie de la couche supérieure de silicium 2 est gravée de manière à former un élément d'ancrage interne au composant horloger, ainsi qu'un pont de matière 8 reliant cet élément d'ancrage 7 à la paroi interne du composant horloger 1, dans une zone non critique de la paroi interne du composant.The components remain attached to the "handle"
Dans l'exemple illustré, la paroi interne du composant horloger est la paroi d'un trou agencé pour recevoir un axe. Le trou, de forme, permet au résidu d'attache de ne pas interférer avec l'arbre coopérant avec la planche en silicium. La paroi interne pourrait être une autre ouverture interne au composant, par exemple si celui-ci est squeletté.In the example illustrated, the internal wall of the watch component is the wall of a hole arranged to receive an axis. The hole, shaped, allows the attachment residue not to interfere with the shaft cooperating with the silicon board. The internal wall could be another internal opening to the component, for example if it is skeletonized.
Bien entendu, le procédé ne saurait se limiter à une gravure DRIE lors de l'étape c). A titre d'exemple, le gravage de l'étape c) pourrait tout aussi bien être obtenue par un gravage chimique dans un même matériau à base de silicium.Of course, the process cannot be limited to DRIE etching during step c). For example, the etching of step c) could just as easily be obtained by chemical etching in the same silicon-based material.
Lors de l'étape c), plusieurs cames peuvent être formées dans le même wafer.During step c), several cams can be formed in the same wafer.
Lors de l'étape d), une seconde opération de photolithographie similaire à la première réalisée lors de l'étape c) est réalisée au dos du wafer 10 (donc côté couche « handle » 12). Pour ce faire le wafer 10 est retourné, la résine y est déposée, puis exposée à travers un masque. Au cours de cette seconde opération de photolithographie, au moins un pont étroit 9 est formé au travers de l'arrière du composant horloger ainsi qu'un ancrage arrière 9' solidaire de l'au moins un pont étroit 9, l'ancrage arrière 9' étant relié à l'élément d'ancrage 7 de la couche « device » par la couche d'oxyde de silicium liant la couche « device » et la couche « handle ».During step d), a second photolithography operation similar to the first carried out during step c) is carried out on the back of the wafer 10 (therefore “handle” layer side 12). To do this, the wafer 10 is turned over, the resin is deposited there, then exposed through a mask. During this second photolithography operation, at least one
Selon l'invention, on forme également un shadow mask intégré lors de la gravure DRIE de la couche « handle » au cours de l'étape d), de manière à réaliser un motif délibéré et volontaire d'ouvertures en face arrière, lesdites ouvertures permettant alors de créer un décor élaboré par dépôt CVD ou PVD lors d'une étape ultérieure.According to the invention, an integrated shadow mask is also formed during the DRIE etching of the “handle” layer during step d), so as to produce a deliberate and voluntary pattern of openings on the rear face, said openings allowing then to create a decoration elaborated by CVD or PVD deposition during a subsequent step.
La zone de la résine exposée est ensuite éliminée au moyen d'un solvant, révélant alors la couche d'oxyde formée précédemment et servant de masque à la une gravure sèche profonde, telle qu'une gravure DRIE, laquelle permet de faire apparaitre l'au moins un pont étroit 9, l'ancrage arrière 9' et le shadow mask.The area of exposed resin is then removed using a solvent, revealing the oxide layer previously formed and serving as a mask for deep dry etching, such as DRIE etching, which makes it possible to reveal the at least a
Lors de l'étape e) pour libérer complètement les composants, les diverses couches d'oxyde de silicium sont alors gravées par le biais d'une gravure humide avec une solution à base d'acide fluorhydrique ou encore par de l'acide fluorhydrique en phase vapeur. Avantageusement, les cames 1 formées sont maintenues à l'élément d'ancrage via le pont de matière 8, et le tout reposant sur l'ancrage arrière relié à l'au moins un pont étroit lui-même relié à un cadre formé dans la couche « handle ».During step e) to completely release the components, the various layers of silicon oxide are then etched by means of wet etching with a solution based on hydrofluoric acid or even by hydrofluoric acid in vapor phase. Advantageously, the cams 1 formed are held to the anchoring element via the bridge of
Selon une étape optionnelle du procédé, l'étape f) consiste à faire subir diverses opérations de terminaison de surface à la pièce libérée et encore tenue par l'attache. Ainsi les faces avant, arrière et/ ou latérales du composant horloger peuvent être travaillées alors que le composant est toujours maintenu au wafer. L'étape de finition peut consister en un dépôt de couches, de structuration ou de décoration sur les différentes faces du composant horloger. Ces opérations sont à caractère fonctionnel (renfort, tribologique,...) ou esthétique (coloration, motif), par PVD ou CVD.According to an optional step of the method, step f) consists of subjecting various surface termination operations to the part released and still held by the fastener. Thus the front, rear and/or side faces of the watch component can be worked while the component is still held on the wafer. The finishing stage may consist of depositing layers, structuring or decoration on the different faces of the watch component. These operations are functional (reinforcement, tribological, etc.) or aesthetic (coloring, pattern), by PVD or CVD.
Au cours de cette étape le motif élaboré au cours de l'étape d) via le shadow mask est également décorées via des dépôts CVD ou PVDDuring this step the pattern developed during step d) via the shadow mask is also decorated via CVD or PVD deposits
On obtient ainsi la came 1 comme illustrée aux
Avantageusement selon l'invention, il est ainsi possible de fabriquer sans plus de complexité un composant horloger 1 comportant un profil externe fonctionnel.Advantageously according to the invention, it is thus possible to manufacture without further complexity a watch component 1 comprising a functional external profile.
Enfin, le procédé peut également comporter l'étape h) destinée à séparer les composant horloger 1 du wafer 10 en séparant le composant 1 de son élément d'ancrage 8.Finally, the method can also include step h) intended to separate the watch component 1 from the wafer 10 by separating the component 1 from its
Bien entendu, la présente invention ne se limite pas à l'exemple illustré, c'est-à-dire la réalisation d'une came, mais est susceptible de diverses variantes et modifications qui apparaîtront à l'homme de l'art.Of course, the present invention is not limited to the example illustrated, that is to say the production of a cam, but is susceptible to various variants and modifications which will appear to those skilled in the art.
Claims (8)
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EP22187006.6A EP4312084A1 (en) | 2022-07-26 | 2022-07-26 | Method for manufacturing a silicon hairspring |
US18/197,302 US20240036524A1 (en) | 2022-07-26 | 2023-05-15 | Method for manufacturing a silicon balance spring |
JP2023090623A JP2024016797A (en) | 2022-07-26 | 2023-06-01 | Method of manufacturing silicon balance spring |
CN202310927619.6A CN117452792A (en) | 2022-07-26 | 2023-07-26 | Method for manufacturing a silicon balance spring |
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Citations (7)
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EP1722281A1 (en) | 2005-05-12 | 2006-11-15 | ETA SA Manufacture Horlogère Suisse | Analogue indicating organ in crystalline material, timepiece provided with such an indicating organ, and manufacturing method thereof |
EP2145857A1 (en) | 2008-07-10 | 2010-01-20 | The Swatch Group Research and Development Ltd. | Method of manufacturing a micromechanical part |
EP3181938A1 (en) | 2015-12-18 | 2017-06-21 | CSEM Centre Suisse d'Electronique et de Microtechnique SA - Recherche et Développement | Method for manufacturing a hairspring with a predetermined stiffness by removing material |
WO2019166922A1 (en) | 2018-03-01 | 2019-09-06 | Csem Centre Suisse D'electronique Et De Microtechnique Sa - Recherche Et Developpement | Method for manufacturing a hairspring |
WO2019180177A1 (en) | 2018-03-21 | 2019-09-26 | Nivarox-Far S.A. | Method for manufacturing a silicon hairspring |
WO2019180596A1 (en) | 2018-03-20 | 2019-09-26 | Patek Philippe Sa Geneve | Method for producing silicon watchmaking components |
CH717124A2 (en) * | 2020-02-12 | 2021-08-16 | Nivarox Sa | A method of manufacturing a device with one-piece flexible silicon blades, in particular for watchmaking. |
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2022
- 2022-07-26 EP EP22187006.6A patent/EP4312084A1/en active Pending
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2023
- 2023-05-15 US US18/197,302 patent/US20240036524A1/en active Pending
- 2023-06-01 JP JP2023090623A patent/JP2024016797A/en active Pending
- 2023-07-26 CN CN202310927619.6A patent/CN117452792A/en active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
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EP1722281A1 (en) | 2005-05-12 | 2006-11-15 | ETA SA Manufacture Horlogère Suisse | Analogue indicating organ in crystalline material, timepiece provided with such an indicating organ, and manufacturing method thereof |
EP2145857A1 (en) | 2008-07-10 | 2010-01-20 | The Swatch Group Research and Development Ltd. | Method of manufacturing a micromechanical part |
EP3181938A1 (en) | 2015-12-18 | 2017-06-21 | CSEM Centre Suisse d'Electronique et de Microtechnique SA - Recherche et Développement | Method for manufacturing a hairspring with a predetermined stiffness by removing material |
WO2019166922A1 (en) | 2018-03-01 | 2019-09-06 | Csem Centre Suisse D'electronique Et De Microtechnique Sa - Recherche Et Developpement | Method for manufacturing a hairspring |
WO2019180596A1 (en) | 2018-03-20 | 2019-09-26 | Patek Philippe Sa Geneve | Method for producing silicon watchmaking components |
WO2019180177A1 (en) | 2018-03-21 | 2019-09-26 | Nivarox-Far S.A. | Method for manufacturing a silicon hairspring |
CH717124A2 (en) * | 2020-02-12 | 2021-08-16 | Nivarox Sa | A method of manufacturing a device with one-piece flexible silicon blades, in particular for watchmaking. |
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