CH716593A2 - Microtechnology part and its manufacturing method. - Google Patents

Abstract

The present invention relates to a method of manufacturing a diamond component (9) comprising the following steps a. making a cut in a diamond wafer by a laser cutting method; b. smoothing the sides (93) of the part (9) cut from the wafer using a plasma, and/or RIE, and/or thermal etching method or any other dry etching method, using at least one gas from among the rare gases (helium, neon, argon, krypton or xenon), oxidizing gases, halogenated gases, nitrogen, hydrogen or a combination of these gases, or any other gas making it possible to etch the diamond to smooth its surface until a roughness Ra of less than 100nm, preferably below 50nm and more preferably 20nm is obtained. The invention also relates to a diamond piece (9) produced by the manufacturing method of the invention.

Description

Description

Field of the invention

The invention relates to the general field of microtechnology and in particular the manufacture of diamond parts using a combination of pulsed laser and plasma etching. The invention relates more particularly to a method which makes it possible, using these two techniques, used successively or simultaneously, to manufacture components in monocrystalline or polycrystalline diamond, which present a level of precision and finish of very good quality (low roughness and excellent aspect ratio)

[0002] The invention also relates to microcomponents such as timepieces produced by the methods of the invention.

The components of the invention find particular application in the watch industry, in particular for the manufacture of movement components or decorative elements for watches.

State of the art

[0004] Micromechanical components have been known and used for decades in watchmaking or in the field of sensors.

[0005] In the vast majority of cases, watch components are made of steel or brass-type alloys and are produced by methods such as machining, stamping or other conventional cutting methods. There are also electromechanical devices (MEMS), which are mostly fabricated from silicon substrates and conventional photolithography methods.

[0006] In the case where the micromechanical components have to slide one over the other, a lubricant is added to improve the friction conditions and prevent premature wear of the components. Lubricants tend over time to lose their properties and the microsystems in which they are used therefore require unwanted maintenance.

[0007] An alternative solution to the use of lubricants is to deposit a carbon-based layer on the Substrate. The solutions proposed consist of the use of layers of amorphous carbon, DLC deposited on steel, or of nanocrystalline diamond on silicon parts. In both cases, the carbon layers can wear out over time and therefore also lead to maintenance operations.

[0008] The document EP 1622826 B1 describes a method for manufacturing a micromechanical component consisting of the separation of a first layer of diamond on a substrate material, the structuring of an edge forming a flank by at least one step of etching using an etch mask on a first surface, which is etched separately or simultaneously with the first layer, and in which the ratio of the etch rates of the first layer and the etch mask is adjusted so that an essentially rectangular edge is formed. However, this process absolutely does not make it possible to obtain roughnesses lower than 100 nm for thicknesses of the parts of more than 100 μm, which makes its use very limited. In the field of watchmaking, for example, the thickness of the parts is typically greater than 100 μm, or even greater than 300 μm.

[0009] The best solution is therefore to directly use a solid part made of carbon and more particularly in its diamond form. In fact, diamond has exceptional mechanical and self-lubricating properties and is therefore an ideal material for this type of application.

[0010] However, the shaping of diamond pieces is relatively complex, in particular to obtain pieces of small dimensions with micrometric precision and flanks with an angular precision of less than one degree. It is also necessary that the areas in contact have average surface roughness of less than 50 nm and ideally 10 to 20 nm, to minimize the coefficient of friction and the rate of wear of the parts.

[0011] The use of methods of the photolithography and etching type, widely used for the manufacture of silicon MEMS, is a possible method. It makes it possible to obtain parts with high dimensional precision, but a drift in the slope is often observed. flanks during engraving, especially for part thicknesses greater than 100 μm. In addition, this method requires the use of many very expensive equipment installed in an ultra-clean environment, which is not compatible with industrial requirements.

[0012] Laser cutting is a very versatile method. It is widely used to cut diamond for jewelry or for high precision tools. The latest generation laser cutting machines make it possible to produce parts with precision compatible with the requirements requested. However, the surface condition after laser cutting is not good enough (high roughness) to allow immediate use of the parts thus cut. An additional step is therefore essential to make the surface of the cut piece clean and free of any particles generated during laser cutting, but also to obtain a smooth surface, especially on the friction zones.

[0013] The shape of the laser beam is often conical, which makes it difficult to obtain flanks with high angular precision. There are mechanical devices (gyroscopic head) making it possible to compensate for the shape of the laser beam, but these devices often prove insufficient in the case of parts with complex geometries.

[0014] Cutting systems which use water-jet guided lasers make it possible, thanks to a non-divergent beam, to obtain straight flanks over thicknesses of several millimeters, but the surfaces obtained do not have any no case of roughness below 100 nm.

Object of the invention

[0015] The present invention proposes a method for producing microtechnical parts in diamond, such as watch components. The method of the invention makes it possible to produce microcomponents which have a thickness greater than 10Opm and having a roughness less than 10Onm, or even less than 50nm and ideally between 10 and 20nm, on all the surfaces of the microcomponents, more particularly on the flanks.

Another object of the invention is to provide components produced by the method of the invention.

[0017] Thus, the present invention relates to a method and a diamond part comprising the characteristics set out in claims 1 to 15

Descriptions of figures

The invention will be better understood on reading the detailed description of an exemplary embodiment given with reference to the appended figures, including:

- Figure 1 shows a rough diamond;

- Figure 2 shows the cut in a rough diamond of a wafer having two parallel faces;

- Figure 3 shows a raw wafer after cutting a raw diamond;

- Figure 4 shows a wafer polished on at least one of its two lower and upper faces, and of controlled thickness;

- Figure 5 shows a substrate on which a layer of polycrystalline diamond is deposited by CVD;

- Figure 6 shows a self-supporting layer of polycrystalline diamond after its Substrate has been removed

- Figure 7 shows a polycrystalline diamond layer resulting from the polishing of at least one of the two upper and lower parallel faces of the self-supported polycrystalline diamond layer. A polycrystalline diamond substrate is thus obtained;

- Figure 8 represents a diamond wafer in which a component is cut by laser;

- Figure 9 represents a raw micromechanical component obtained after laser cutting;

- Figure 10 represents a smooth micromechanical component after post-processing. The component is delimited by its upper and lower face, and all its side faces;

- Figures 11A and 11B present process steps for obtaining a polished plate on which a thin layer has been deposited at least on its upper face. Figure 11A shows a top view and Figure 11B a sectional view. A coated wafer obtained is illustrated;

- Figure 12 shows a coated wafer after laser cutting and a cut slice. A coated and cut wafer obtained is illustrated;

- Figure 13 shows a piece after engraving of the diamond and its engraved edge;

- Figure 14 shows a part after etching a thin layer. A cut wafer obtained is illustrated;

- Figure 15a,b shows a cut piece with a coating. Figure 15c shows an enlargement of the sidewall of the part of Figure 15b illustrating a layer covering a rough sidewall. Figure 15c also shows a depth of engraving to smooth the side of the part.

- Figure 16 shows the side of a finished part, after engraving according to Figure 15c.

Description of embodiments of the invention

[0019] The present invention relates to a method of manufacturing micromechanical diamond components.

[0020] The manufacturing method for micromechanical diamond components breaks down into the following manufacturing steps:

The essential steps of the manufacturing method of the invention are as follows (ad):

To. making a cut in a 3,4,7,8 diamond wafer using a laser cutting method;

b. carrying out the smoothing of the flanks of the piece cut out in the wafer, using a plasma etching method, and/or RIE, and/or thermal or any other dry etching method, using at least one gas from among rare gases (helium, neon, argon, krypton or xenon), oxidizing gases, halogen gases, nitrogen, hydrogen or a combination of these gases.

The oxidizing gas may be oxygen. The halogen gas can be a carbon halogen gas such as for example CF4, C2F6. The halogen gas can also be non-carbon such as for example SF6. Any other gas can be used for etching the diamond to smooth its surface until a roughness Ra of less than 100 nm, preferably below 50 nm and ideally less than 20 nm, is obtained.

[0021] In a preferred embodiment, step (b) which consists in smoothing the sides 93 of the cut piece 9, is carried out using an etching method or any other means other than mechanical polishing.

[0022] In one embodiment, a step (c) is carried out consisting of cleaning the uncut flanks of the cut piece 9. This cleaning is preferably done using chemical solutions or any other suitable means;

In one embodiment, a step (d) of etching the cutting sides of the cut piece 9 is carried out. This etching is preferably done by a dry method in an oven or a plasma reactor or by any other suitable means;

In one embodiment, a deposit of a thin protective layer 111 on at least one of the two surfaces 41 or 42 is made;

In one embodiment, said first surface 41 and said second surface 42 are polished, not necessarily with the same degree of polishing. In such a case, the polishing of the first and second faces 41,42 must be carried out on the initial wafer before laser cutting.

In one embodiment only one of the faces 41,42 is polished.

In one embodiment none of the faces 41,42 is polished.

[0028] It is understood that a piece of the invention may comprise more than two faces, for example in the case of a base piece which has a hexagonal section, and that at least one of the faces of the piece of hexagonal shape can undergo smoothing treatment. In other variants, a part may comprise a central opening and the surface of this central opening may undergo a smoothing treatment as described in the invention. This can be useful in order to make a diamond piece in which an axis must be inserted.

[0029] The raw material for making the microcomponent is a diamond wafer. This wafer can be either monocrystalline diamond or polycrystalline diamond, as described now

A preferred method of obtaining single crystal diamond wafer is described below.

- The raw material is a rough diamond 1 (Figure 1). The rough diamond can be natural or synthetic. In the case of synthetic diamond, the manufacture is done for example by HPHT (High Pressure High Temperature) or CVD (Chemical Vapor Deposition) growth.

- The raw diamond is then cut 2 along two parallel faces 21 and 22 by laser (Figure 2). A raw wafer3 (FIG. 3) is thus obtained.

- The raw wafer 3 can then be polished by standard methods on at least one of the two upper and lower 41 faces 42. A polished wafer 4 is obtained. It is defined by its controlled thickness t (± 1 to 5 μm) and its mean surface roughness on the polished surfaces 41 and 42 with a value between 0.1 and 200 nm (FIG. 4).

An advantageous method of obtaining polycrystalline diamond wafer is described below.

- The raw material is a layer of polycrystalline diamond 6 deposited on a Substrate 5 by CVD (Figure 5). The substrate can be silicon or one of its compounds (Si-N, Si-C) or a refractory metal.

- The diamond layer is then released from the substrate either by chemical etching or by mechanical methods. A self-supporting polycrystalline diamond layer 7 is thus obtained. The term self-supporting means that the diamond piece does not require support or substrate and can be manipulated freely, either by an automaton or manually, for example by tweezers.

- The diamond layer 7 can then be polished by standard methods on at least one of the two upper 71 and lower 72 faces. A polished wafer 8 in polycrystalline diamond is obtained. It is defined by its controlled thickness t (± 1 to 5 pm) and its average surface roughness on the two polished surfaces 81.82 with a value between 0.1 and 200 nm (Figure 7).

[0032] In a variant of the method, the raw wafer 3, 7 (FIGS. 3, 6) will then undergo a series of preferred treatments in order to be transformed into a micromechanical part ready to be used.

[0033] In a variant, the polished wafer 4.8, (Figures 4, 7) will then undergo a series of preferred treatments in order to be transformed into a micromechanical part ready to be used.

The first embodiment of the proposed method comprises the following steps:

- Deposit of a thin layer 111 on all sides of a wafer 3,4,7,8 in order to obtain a coated wafer 11 (Figure 11). This thin layer 111 can for example be made up of materials of the nickel, aluminum or any other material that etch at a much slower speed than diamond (at least a ratio of 2 between the etching speeds). This step is optional.

- Cutting of the wafer 3,4,7,8,11 with a laser cutting method over the entire thickness of the wafer (Figures8, 9). The laser beam used is preferably pulsed over very short periods (femto or nanosecond). The laser may use an ultraviolet, visible or infrared laser, the laser may be guided by a water jet. A cutting component 9 is thus obtained (FIG. 9).

- Cleaning of the cut component 9 (example in Figure 9) to remove the cutting residues. This cleaning step will preferably be done wet in a suitable solution such as a nitric acid mixture.

and oxygenated water, called by those skilled in the art, Piranha solution. Other cleaning solutions based on acids, bases or solvents can also be used. An ultrasonic bath can also be used advantageously to facilitate the detachment of the particles stuck to the surface of the cut piece. A piece free of cut residues is obtained. This step is optional.

- Etching of any non-diamond carbon layer resulting from the interaction between the laser and the diamond surface. The etching will preferably be done by dry methods in a lathe or in a plasma reactor using gaseous mixtures preferentially etching the non-diamond phases of the diamond, such as hydrogen or oxygen. A part without a non-diamond carbon layer is obtained. This step is optional.

- Smoothing of the sides of the cut piece 9.11 to reduce their surface roughness. A clean part 13 is thus obtained (FIG. 10) with smooth surfaces 131, 132, 133. Several smoothing methods are possible (examples below).

- Etching the thin layer 111 by a method recommended for the type of material used in the thin layer, in order to completely remove the thin layer. This step is only carried out in the case where the step of deposition of the thin layer 111 is carried out.

The possible smoothing methods are preferably the following:

- Heat treatment in a conventional oven in a controlled atmosphere with a gaseous mixture allowing the diamond to be engraved, such as oxygen.

- Chemical etching in a plasma reactor in which mainly neutrals and radicals are created from a gaseous mixture allowing the etching of the diamond to smooth its surface (02, Ar, CF4, SF6...)

- Plasma etching in a plasma reactor of the RIE type (Reactive Ion Etching) in which ions are created in addition to neutrals and radicals, an ion bombardment is added to the chemical reactions of the neutrals and radicals by polarizing the cut piece. Gas mixtures allowing the diamond to be etched to smooth its surface (02, Ar, CF4, SF6.) will preferably be used.

According to a variant of the method and in order to obtain a lower roughness, the advantageous method comprises the following steps, illustrated in Figures 15a-c

- Deposit of a smoothing layer 15a on a cut component 9.11 created by laser cutting and burn at the same speed as diamond. This smoothing layer can be either organic (photolithography resin, for example), or inorganic (nitride or oxide layer), and must be able to be deposited easily on the sides.

- Complete etching of the smoothing layer and partial of the diamond over a depth p at least greater than the total height of the roughness profile of the sides of the cut piece, Rt, defined by the vertical difference between the maximum height of the peaks and the depth maximum of the valleys over the measurement length.

- Cleaning of the piece with a process to remove all etching residues. After this step, the state of the final part18 is that shown in Figure 16.

[0037] According to a variant of the method in order to obtain cutting flanks with the greatest angular precision, the method comprises the following steps, illustrated in figures 11A, B-14:

- Deposit of a thin layer 111 on a polished wafer 3,4,7,8 in order to obtain a coated wafer 11 (Figures 11A,11B). This thin layer 111 can for example be made up of materials of the nickel, aluminum or any other material that etch at a much slower speed than diamond (at least a ratio of 2 between the etching speeds).

- Cutting of the wafer 11 by laser in order to obtain a cut wafer 14. The cut face 141 presents an angle that does not comply with the specifications of the final part (Figure 12).

- Plasma etching of the wafer 14 in order to obtain a part 15 whose face 151 presents an angle conforming to the specifications of the final part (Figure 13).

- Etching the thin layer 111 by a method recommended for the type of material used in the thin layer, in order to completely remove the thin layer (Figure 14).

- Obtain a 16 diamond piece that can be used as it is.

[0038] The invention is also embodied by a reactor comprising a vacuum enclosure, a system for producing a plasma in this enclosure as well as a machining laser. In variants the laser is arranged outside the vacuum enclosure and the wall of the enclosure comprises at least one window arranged to pass the layer ray which is directed onto the diamond piece to be machined. In another variant at least part of the laser is arranged in the vacuum enclosure. The laser beam, which can be outside or inside the reactor, used is preferentially pulsed over very short periods (femto or nanosecond). The laser may use an ultraviolet, visible or infrared laser.

[0039] For watch components, the quality of the sides of the parts is particularly important. It is therefore appropriate to provide in some cases additional process steps. For example, in a Variant of the method, at least one roughness measurement step can be implemented. This step can be followed by engraving or laser machining steps to further improve the roughness. For example, after a series of engraving and laser processing steps, an image of the side of the part is produced and its roughness determined. If the roughness on at least a portion of the sidewall is not sufficient, a laser beam is directed onto this area in order to further reduce its roughness.

[0040] Alternatively, other laser beams or additional passes with the same laser beam may be used to improve the roughness of the sidewalls. This can be achieved by a laser beam which is directed and focused on the sidewall areas of the part. This makes it possible to obtain very smooth sides, for example typically having a roughness of less than 20 nm.

[0041] It is understood that in all embodiments the parameters may vary, namely:

- laser wavelength between 200nm and 15pm

- Use of laser in cw (continuous wave) or pulse mode

- composition of one or more gases

- gas pressure between 0.001 - 100 mbar

Examples of realization

[0042] The dimensions and shapes of the typical parts described below are typical embodiments and are not limiting and can therefore be varied by at least one order of magnitude, ie smaller or larger. In principle the pieces have a typical dimension less than 10mm in their maximum dimension but there is no consistency as to the shape or size of the pieces of the invention.

[0043] In a first example,

1. A polished plate is obtained from a CVD diamond following the transformation steps described in figures 1 to 4. It has an initial thickness of 505 μm

2. Next, a watch movement spiral spring is cut using a visible nanosecond laser (515nm) according to the process described in figure 8.

3. The cut piece is then etched in an ICP type plasma etching reactor with the following etching conditions

- Power of the plasma = 1000W, Polarization of the Substrate = SOOW. The term "Polarization" here means Polarization of the substrate by application of a potential difference of a given power between the Substrate and the reactor

- 02 = 100 sccm (Standard cubic centimeter per minute), Ar = 100 sccm

- Gas pressure = 5 mbar

4. A final part with a final thickness of 500pm and an average roughness on the sides of 0.2pm is thus obtained.

In advantageous variants of said first embodiment, the following parameters can be varied as follows:

- Laser wavelength between 400nm-690nm

- Plasma powers between 100W and 2000W

- Substrate bias: between 10 W and 500W

- Gas pressure between 1 mbar and SOmbar

[0045] In a second example,

1. A polished plate is obtained from an HPHT diamond following the transformation steps described in figures 1 to 4. It has an initial thickness of 122 μm

2. Next, an escape wheel of a watch movement is cut using a UV femto-second laser (343 nm) according to the process described in figure 8.

3. The part is then cleaned in a Piranha mixture (proportion of HNO3:H2O2 equal to 3:1) in an ultrasonic bath for 30 min. at 60°C.

4. The non-diamond phases present on the cut flanks are etched in a plasma-microwave reactor for 5 min. in a gas mixture 1% O2 in H2.

5. The cut and clean piece is then etched in an RF plasma reactor of the lacquerer type with the following process conditions:

- RF power = 200W

- 02 = 20 sccm,

- Pressure = 2 mbar

6.A piece with a final thickness of 120pm and an average roughness on the sides of 0.1pm and thus obtained after the etching step.

In advantageous variants of said second embodiment, the dimensions of the parts can be different and the following parameters can be varied as follows:

- Laser wavelength between 250nm-450nm

- RF power between 100 and 500W

- O2 flow: between 5 and 50 sccm

- Gas pressure between 1 and 20 mbar

- Etching in a plasma-microwave reactor for 1 to 10 min. in a gas mixture between 0.01 and 10% 02 in H2.

[0047] In a third example,

1. A polished plate is obtained from a natural diamond following the transformation steps described in figures 1 to 4. It has an initial thickness of 390 μm.

2. A layer of nickel 1 μm thick is deposited on its upper face by a galvanic process following the process described in figure 11.

3. Then an anchor lift of a watch movement is cut out using a visible nanosecond laser (515nm) guided by a water jet according to the process described in figure 8.

4. The part is then cleaned in a Piranha mixture (HNO3:H2O2 3:1) in an ultrasonic bath for

30 mins. at 60°C.

5. The cut piece is then etched using the process described in Figures 12 to 15 in an ICP type plasma etching reactor with the following etching conditions

- Plasma Power = 1000W, Substrate Bias = 300W

- 02 = 50 sccm, Ar = 100 sccm, C2F6 = 20 sccm

- Pressure = 10 mbar

6. The nickel layer is chemically etched in an aqua regia bath.

7. A part with a final thickness of 390µm, an average roughness on the sides of 0.05µm and a verticality of the sides of 89.5° and thus obtained.

In such an example, there is no reduction in thickness during the process because the nickel layer prevents the upper layer from being etched.

In advantageous variants of said third embodiment, the following parameters can be varied as follows:

- Laser wavelength between 250nm-450nm

- Plasma power between 100 and 500W

- Substrate Bias Power between 0 and 500W

- Flow of O2: between 5 and 200 sccm, Ar between 0 and 200sccm, C2F6 between 0 and 10Osccm

- Gas pressure between 1 and 20 mbar

- Etching in a plasma-microwave reactor for 1 to 10 min. in a gas mixture between 0.01 and 10% 02 in H2.

[0050] In a fourth example,

1. A polished plate is obtained from a polycrystalline CVD diamond doped with boron deposited on a silicon substrate following the transformation steps described in FIGS. 5 to 7. It has an initial thickness of 90 μm.

2. A layer of titanium 0.5 pm thick is deposited on its upper face by a cathodic sputtering process according to the process described in figure 11.

3. An implant for the inner ear is cut using a femtosecond visible laser (515nm) following the procedure described in figure 8

4. The piece is then cleaned in an ultrasonic bath for 30 min. with acetone at room temperature

5. The non-diamond phases present on the cut flanks are etched in a plasma-microwave reactor for 15 min. in pure H2.

6. The cut and clean piece is then etched in an MW plasma reactor of the paint-removal type with the following process conditions:

- MW power = 500W

- 02 = 20 sccm, CF4 = 30 sccm

- Pressure = 1 mbar

7. The titanium layer is chemically etched in a hydrochloric acid bath.

8. A part with a final thickness of 90µm and an average roughness on the sides of 0.1µm and a verticality of the sides of 89° and thus obtained at the end of the process.

In advantageous variants of said fourth embodiment, the dimensions of the parts can be different and the following parameters can be varied as follows:

- Laser wavelength between 200nm-690nm

- MW power between 100 and 2000W

- Flow of O2: between 5 and 200 sccm, Ar between 0 and 200sccm, C2F6 between 0 and 10Osccm

- Gas pressure between 1 and 20 mbar

- Etching in a plasma-microwave reactor for 1 to 10 min. in a gas mixture between 0.01 and 10% 02 in H2.

- Cleaning the part in an ultrasonic bath for 1 min. at 90min with acetone at room temperature, or a temperature between 20 and 50°C

- Etching of the non-diamond phases present on the cut sides in a plasma-microwave reactor for 1 min to 30 min. in pure H2 or 0.01 and 10% 02 in H2.

[0052] In a fifth example,

1. A polished plate is obtained from a CVD diamond following the transformation steps described in figures 1 to 4. It has an initial thickness of 300 μm

2. Next, an escape wheel of a watch movement is cut using a UV femto-second laser (343 nm) according to the process described in figure 8.

3. The part is then cleaned in a Piranha mixture (HNO3:H2O2 3:1) in an ultrasonic bath for 30 min. at 60°C.

4. An SU-8 type photolithography resin is applied to the cut piece in a spin-coater.

5. The cut piece is then etched in an ICP type plasma etching reactor with the following etching conditions

Plasma Power = 1000W, Substrate Bias = 300W

O2 = 50 sccm, Ar = 100 sccm, C2F6 = 20 sccm

Pressure = 10 mbar

6. The treated part is cleaned in a bath of PM Acetate.

7. A part with a final thickness of 280µm and an average roughness on the sides of 0.05µm and a verticality of the sides of 89.5° is thus obtained.

In advantageous variants of said fifth embodiment, the dimensions of the parts can be different and the following parameters can be varied as follows:

- Laser wavelength between 200nm-690nm

- Plasma power between 100 and 2000W

- Substrate Bias Power between 0 and 500W

Claims (15)

- Flux of 02: between 5 and 200 sccm, Ar between 0 and 200sccm, C2F6 between 0 and 10Osccm - Gas pressure between 1 and 50 mbar - The resin layer can be removed by other suitable solvents such as toluene. [0054] In a sixth example, 1. A polished plate is obtained from a CVD diamond following the transformation steps described in figures 1 to 4. It has an initial thickness of 150 μm 2. Next a micromotor gear is cut using a VIS femto-second laser (633nm) following the process described in Figure 8. 3. The part is then cleaned in an ultrasonic bath for 30 min. with acetone at room temperature 4. The non-diamond phases present on the cut flanks are etched in a plasma-microwave reactor for 5 min. in a gas mixture 1% 02 in H2. 5. A layer of silicon dioxide is deposited by PECVD (Plasma Enhanced Chemical Vapor Deposition) on the cut and clean piece. 6. The part is then etched in an ICP type plasma etching reactor with the following etching conditions Plasma Power = 600W, Substrate Bias = 200W 02 = 50 sccm, SF6 = 20 sccm Pressure = 2mbar 7. The treated part is cleaned in a bath of hydrofluoric acid to eliminate the residues of the layer of silicon dioxide. 8. A part with a final thickness of 145µm and an average roughness on the sides of 0.03µm and a verticality of the sides of 89.5° is thus obtained. In advantageous variants of said sixth embodiment, the dimensions of the parts can be different and the following parameters can be varied as follows: - Laser wavelength between 400nm-1500nm - Plasma power between 100 and 2000W - Substrate Bias Power between 0 and 500W - Flux of 02 between 1 and 200 sccm, SF6 between 0 and tOOsccm - Gas pressure between 0.1 and 50 mbar - The SiO2 layer can also be deposited by cathodic sputtering. [0056] Although a preferred application of the invention relates to the field of watchmaking, it is not limited to watchmaking. For example, diamond components which are intended for the fields of medicine or instruments, industrial machines or even sensors or actuators, can also be produced. Other applications are also possible. Claims 1. Method for manufacturing a diamond component comprising the following successive steps (a,b): To. making a cut in a diamond wafer (3,4,7,8) by a laser cutting method; b. carrying out the smoothing of the flanks of the piece cut out in the wafer, using a plasma etching method, and/or RIE, and/or thermal or any other dry etching method, using at least one gas from among rare gases (helium, Neon, Argon, Krypton or Xenon), oxidizing gases, halogen gases, nitrogen, hydrogen or a combination of these gases, or any other gas allowing the diamond to be engraved to smooth its surface until obtaining a roughness Ra below 100 nm, preferably below 50 nm and more preferably below 20 nm 2. Method according to claim 1 comprising, before said step (b), a step (c) of carrying out cleaning of the rough-cut flanks of the cut-out piece in the wafer (3,4,7,8) using chemical solutions or any other suitable means. 3. Method according to claim 1 or 2 comprising, before said step (b), a step (d) of etching the sides of the cut piece in the wafer, and this using a dry method in an oven or a plasma reactor or any other suitable means. 4. Method according to one of claims 1 to 3 in that step (b) of smoothing at least one of the sides of the wafer (3,4,7,8) is carried out by means other than mechanical polishing. 5. Method according to one of the preceding claims comprising the simultaneous combination of at least one laser cutting step and at least one flank smoothing step. 6. Method according to one of the preceding claims wherein the diamond plate (3,4,7,8) is a piece of solid diamond comprising a first surface and a second surface as well as a lateral flank linking the two said surfaces. 7. Method according to claim 6 wherein said piece of solid diamond (3,4) is a natural monocrystalline diamond. 8. Method according to claim 6 wherein said piece of solid diamond is a synthetic diamond produced by CVD or HPHT method. 9. Method according to claim 6 wherein said piece of solid diamond (7,8) is a polycrystalline diamond produced by CVD method. 10. . Method according to one of claims 6 to 9 in that at least one of the surfaces of the diamond plate (3,4,7,8) is polished. 11. Method according to one of claims 1 to 10 in that at least one plasma etching step is carried out at the same time as a laser cutting step. 12. Method according to claims 1 to 11 additionally comprising at least one of the following steps (e-h): - e) depositing a thin layer (111) on a wafer (3,4,7,8), which has been , in order to obtain a coated wafer (11); - f) cutting the wafer (11) by laser in order to obtain a cut wafer (14). The cut face (141) presents an angle or a surface condition that does not comply with the specifications of the final part; - g) carry out a plasma etching of the wafer (14) in order to obtain a part (15) whose face (151) has an angle or a surface condition in accordance with the specifications of the final part; - h) carry out an etching of the thin layer (111) in order to completely remove the thin layer. A clean part (16) is obtained. 13. Method according to claim 12 in that the thin layer (111) is composed of materials such as nickel, aluminum or any other material that etches at a speed at least twice as slow as diamond. 14. Method according to claim 1 wherein instead of step (b) steps (i-k) are carried out: - I) application of a smoothing layer (171), which can be etched at the same speed as diamond and which can be inorganic or inorganic, on the cut component so that it fills the roughness created by the laser cut, - j) etching, at least partially, of the lachte smoothing layer at the same time as the diamond layer to a depth (p) at least greater than the total height of the roughness profile of the sides of the cut piece, - k) cleaning of the sides of the part by a suitable process to remove all etching residues. 15. Diamond piece (9,13,16,18) manufactured according to the manufacturing method of one of the preceding claims.