Method of coring and slicing a cnd diamond article and apparatus for performing the method

Abstract

The present invention relates to the field of chemical vapor deposition (CVD) diamond and its post-fabrication processing. In particular, the present invention provides a method for coring and slicing a CVD diamond article, wherein the CVD diamond article comprises CVD diamond and graphitized material covering a plurality of sides of the diamond. The method is performed by a device that provides a laser beam coupled into a fluid jet. The method comprises, for coring, cutting the article with the laser beam to remove the graphitized material from the sides of the diamond. The method further comprises, for slicing, cutting one or more thin sections from the diamond with the laser beam.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of chemical vapor deposition (CVD) diamond and its post-manufacturing processing. In particular, the present invention provides a method for coring and slicing a CVD diamond article, wherein the CVD diamond article comprises CVD diamond and a graphitized material covering the sides of the diamond. The method is performed by a device providing a laser beam coupled into a fluid jet. BACKGROUND

[0002] CVD diamond is a man-made diamond manufactured in a laboratory, and CVD is a process performed in a controlled laboratory and yields exact physical and chemical properties of natural diamond. The CVD method comprises placing a diamond seed into a vacuum chamber and filling the vacuum chamber with a carbon-rich gas at a temperature close to 815°C. The gas becomes a plasma at such a high temperature, thereby causing carbon sheets to be released. These carbon sheets are layered onto the diamond seed in the vacuum chamber, resulting in CVD diamond growth. The final CVD diamond article comprises the grown CVD diamond and a thick graphitized layer or sheet that typically covers the sides of the diamond. CVD diamond is typically grown from a seed diamond plate that will become part of the new CVD diamond. The growth is mainly in one direction, but can also be in the other two directions.

[0003] For further processing of the grown CVD diamond (article), the graphitized layer or sheet needs to be removed from the diamond, which is referred to as "coring" the CVD diamond. Furthermore, it can also be desirable to divide the CVD diamond into a plurality of smaller pieces, for example into thin slices, which is referred to as "slicing" the CVD diamond.

[0004] Typically, the steps of coring and slicing the diamond are performed separately, and both steps have specific drawbacks. For example, coring the CVD diamond is typically a very lengthy and tedious process. Furthermore, it is also often a problem that diamond is wasted due to limited coring precision. After coring, the CVD diamond needs to be manipulated in order to enable subsequent slicing, which will further result in time loss. Furthermore, it is difficult to slice the diamond due to its hardness and relatively high thickness. As a result, the obtained diamond slices are typically not strictly parallel and have a rather rough cut surface. In addition, micro-cracks often spoil the quality of the cut slices. Furthermore, the thinness of the slices is also limited, so that the diamond can typically only be divided into a certain maximum number of slices.

[0005] It is therefore an object of embodiments of the present application to improve the conventional way of coring and slicing CVD diamond (articles). In particular, it is an object to provide a method and apparatus which is capable of fully automatically coring and slicing CVD diamond starting from a CVD diamond article, i.e. without any human action and without any intermediate handling of the article.

[0006] The overall processing time for obtaining diamond lamellas from a CVD diamond article should be significantly reduced. Furthermore, the lamellas should be manufactured with a very high precision, i.e. with an improved surface roughness and in a way that they are more parallel to each other than conventionally obtained lamellas. Moreover, the lamella quality should be improved, in particular with less micro cracks and a reduced surface roughness. Another goal is to increase the number of lamellas obtainable from a diamond, i.e. to make the diamond lamellas thinner. In addition, the loss of material within the cutting kerf should be reduced because the cutting kerf width is reduced for larger thicknesses of the diamond article.

[0007] The above goals should be achievable in particular for all types of CVD diamond. In particular, for coring and slicing CVD diamond articles, there is no solution for a fully automatic process so far. SUMMARY

[0008] This object is achieved by the embodiments presented in the independent claims. Advantageous implementations of these embodiments are defined in the dependent claims.

[0009] In particular, embodiments of the present application are generally based on the use of an apparatus for implementing a method of coring and slicing a CVD diamond article, wherein the apparatus provides a laser beam guided by internal reflection in a fluid jet. The fluid jet guided laser beam can effectively cut the graphitized material as well as the superhard diamond of the article with a very high precision. For example, the cutting can be performed with a very narrow and constant kerf and with a very small taper. This allows in particular to cut out completely parallel lamellas with a cubic plate shape having right angles.

[0010] A first aspect of the present application provides a method for coring and slicing a CVD diamond article, the article comprising diamond and a graphitized material covering a plurality of sides of the diamond, wherein the method is performed by an apparatus providing a laser beam coupled into a pressurized fluid jet, and wherein the method comprises, for coring, cutting the article with the laser beam to remove the graphitized material from the sides of the diamond, and for slicing, cutting one or more lamellas from the diamond with the laser beam.

[0011] The method of the first aspect allows coring (removing one or more graphitized sheets or layers from a diamond; especially, the "graphitized material" can comprise a mixture of diamond and graphite in the composition) and slicing (producing one or more thin sheets of diamond) in a fully automated manner and with a significantly shorter processing time. No manual work or handling of the diamond is required, especially between the coring step and the slicing step. Furthermore, very thin sheets, sheets that are strictly parallel, sheets with greatly improved (i.e. lower surface roughness), and sheets without micro-cracks can be obtained.

[0012] In an implementation form of the method of the first aspect, for performing the coring, the article is positioned in a first orientation, and for performing the slicing, the article is positioned in a second orientation.

[0013] In an implementation form of the first aspect, the method further comprises measuring a surface orientation of a top surface and / or a bottom surface of the diamond, and determining the second orientation and / or a slicing direction for the slicing based on the measured surface orientation.

[0014] That is, a top surface and / or a bottom surface of the CVD diamond can be measured first, to then adapt to the measured orientation. The measured surface can correspond to a surface of a seed plate from which the CVD diamond has grown. The slicing direction can be adjusted to be parallel to the measured surface, or to a crystal orientation derived from the surface. The surface orientation can be measured by a distance sensor (e.g. an optical sensor or a touch probe), e.g. with at least three measurement points. The distance sensor can be part of the apparatus.

[0015] In an implementation form of the method of the first aspect, the first orientation for the coring is the same as the second orientation for the slicing; or, the second orientation for the slicing is tilted by 5°-20°, especially 10°-20°, relative to the first orientation for the coring; or, the second orientation for the slicing is rotated by 90° relative to the first orientation for the coring.

[0016] Thereby, a particularly fast (shorter processing time) and efficient coring and slicing process is achieved. By the tilt of the two orientations, the diamond can be sliced from both sides.

[0017] In an implementation form of the method of the first aspect, the slicing comprises positioning the article in the second orientation to initiate cutting a set of sheets from the diamond, and rotating the article by 180° to complete cutting the set of sheets from the diamond.

[0018] Thus, the method can comprise cutting twice (from different sides) inside the same kerf. This can allow cutting thicker CVD articles and / or diamonds.

[0019] In a implementation form of the method of the first aspect, the method further comprises: trimming the CVD diamond article by cutting the diamond parallel to a top surface and / or a bottom surface of the diamond with the laser beam; wherein, for the trimming, the article is positioned in a third orientation.

[0020] The trimming step further improves the quality of the wafer obtained after slicing. For example, graphitized layers on the top surface and / or the bottom surface can be removed and thus do not need to be removed from the wafer anymore. Mechanical polishing is not needed. Furthermore, the dimensions of the wafer can be determined by the trimming step.

[0021] In a implementation form of the method of the first aspect, the method comprises: for the coring: cutting the article along a first side surface of the diamond with the laser beam to remove a first graphitized piece; and cutting the article along a second side surface of the diamond opposite to the first side surface with the laser beam to remove a second graphitized piece; after the coring, for the trimming: repositioning the article in the third orientation; cutting the diamond parallel to a top surface of the diamond with the laser beam, and cutting the diamond parallel to a bottom surface of the diamond with the laser beam; after the trimming, for the slicing: repositioning the article in the second orientation; cutting the article along a third side surface of the diamond perpendicular to the first side surface and the second side surface with the laser beam to remove a third graphitized piece; and cutting one or more wafers from the diamond with the laser beam, wherein each wafer is cut parallel to the cutting along the third side surface, and wherein a last wafer is cut along a fourth side surface of the diamond opposite to the third side surface.

[0022] This implementation form enables a particularly fast and complete coring, trimming and slicing of the diamond. No manual work is needed, i.e. no intermediate handling. A plurality of CVD articles can be effectively successively coring, trimmed and sliced in this way.

[0023] In one example of this implementation form, 14 diamond wafers of 5 x 7 x 0.25 mm each are manufactured, with a cutting time of only 35-40 minutes for each CVD diamond article for all steps.

[0024] In a implementation form of the method of the first aspect, the method comprises: rotating the article by about 90° from the first orientation for the coring to the third orientation for the trimming; and rotating the article by about 90° from the third orientation for the trimming back to the second orientation for the slicing or keeping the same orientation for the slicing.

[0025] In an implementation form of the method of the first aspect, trimming the article comprises cutting the top and bottom faces of the diamond such that all faces of the diamond have a determined size and orientation.

[0026] In an implementation form of the method of the first aspect, the slicing comprises cutting the one or more wafers parallel to the top and / or bottom face of the diamond from the diamond.

[0027] In an implementation form of the method of the first aspect, the method further comprises successively coring and slicing each of one or more further articles in the same way as the article.

[0028] This batch processing further shortens the processing time of each article.

[0029] In an implementation form of the method of the first aspect, the method is performed automatically and / or continuously by the device; and / or the method is performed by the device in a single process.

[0030] In an implementation form of the method of the first aspect, 5 to 20 wafers, in particular 10 to 15 wafers, are cut from the diamond.

[0031] Thus, an increase of about 50% of wafers can be obtained compared to conventional coring and slicing methods.

[0032] In an implementation form of the method of the first aspect, the thickness of each wafer is in the range of 0.1 - 0.4 mm, in particular in the range of 0.2 - 0.3 mm.

[0033] Thus, the obtained diamond wafers are thinner than wafers obtained with conventional coring and slicing methods.

[0034] In an implementation form of the method of the first aspect, the average surface roughness of the cut surface of the wafer is in the range of 200 - 600 nm, in particular in the range of 300 - 500 nm.

[0035] Thus, an improved surface roughness compared to conventional coring and slicing methods is achieved. Very smooth wafers are obtained. For example, an average surface roughness of 367 nm was measured in one example, in which 14 wafers were manufactured (5 x 7 x 0.25 mm each). No further mechanical polishing is required. The method is particularly advantageous for large wafer sizes of e.g. 10 x 10 mm or up to 20 x 20 mm.

[0036] In an implementation form of the method of the first aspect, the kerf produced by cutting with the laser beam is in the range of 25-100 pm, in particular in the range of 40-60 pm; and / or, the taper produced by cutting with the laser beam is in the range of 1°-2°, in particular less than 1°.

[0037] Thus, it is possible to cut, in particular slice, the diamond with particular precision. Furthermore, the narrow kerf reduces the diamond material lost inside the kerf.

[0038] In an implementation form of the method of the first aspect, cutting with the laser beam comprises multi-pass cutting with a displacement speed of the laser beam relative to the article in the range of 3-20 mm / s.

[0039] This allows coring and slicing of the article at very high speed, resulting in significantly reduced processing time.

[0040] In an implementation form of the method of the first aspect, cutting the diamond comprises cutting along a determined crystal orientation of the diamond.

[0041] Thus, the diamond flake can be completely parallel and can have a very low surface roughness. Furthermore, micro-cracks can be effectively avoided. Furthermore, this is also advantageous when the flake is to be reused as seed for new CVD diamond growth.

[0042] In an implementation form of the method of the first aspect, the laser beam is a pulsed laser beam, and a pulse intensity of the laser beam in the fluid jet is in the range of 0.8-2.0 GW / cm 2 and / or, an average power of the laser beam is in the range of 20-300 W and a pulse length of the laser beam is in the range of 150-400 ns.

[0043] In this way, the diamond can be cut very quickly and with high precision.

[0044] In an implementation form of the method of the first aspect, the method further comprises receiving, by the device during cutting the article, laser-induced electromagnetic radiation propagating out of the article, in particular radiation from a plasma formed at a surface of the article by cutting the article with the laser beam; converting the received radiation into a signal; and determining, based on the signal, whether the laser beam has penetrated the article.

[0045] By determining when the laser beam has penetrated the article, e.g. penetrated the graphitized material or the diamond, depending on which is cut, the processing time can be reduced again.

[0046] In an implementation form of the method of the first aspect, the laser-induced electromagnetic radiation is received by the device through the fluid jet.

[0047] This enables a very compact device. Furthermore, the sensitivity of the measurement of the generated radiation is high, so that an accurate cutting control can be achieved.

[0048] A second aspect of the present application provides a device for coring and slicing a CVD diamond article, the CVD diamond article comprising diamond and graphitized material covering a plurality of sides of the diamond, the device comprising: a machining unit configured to provide a laser beam coupled into a pressurized fluid jet; and a control unit configured to control the machining unit to: for the coring, cut the article with the laser beam to remove the graphitized material from a side of the diamond; and for the slicing, cut one or more thin slices from the diamond with the laser beam.

[0049] In an implementation form of the device of the second aspect, the control unit is further configured to: for the coring, position the article in a first orientation, and for the slicing, position the article in at least a second orientation.

[0050] In an implementation form of the device of the second aspect, the control unit is further configured to control the machining unit to: edge the CVD diamond article by cutting the diamond with the laser beam parallel to a top surface and / or a bottom surface of the diamond; wherein for the edging, the article is positioned in a third orientation.

[0051] In an implementation form of the device of the second aspect, the control unit is configured to: for the coring: cut the article with the laser beam along a first side of the diamond to remove a first graphitized slice; cut the article with the laser beam along a second side of the diamond opposite to the first side to remove a second graphitized slice; after the coring, for the edging: reposition the article in the third orientation; cut the diamond with the laser beam parallel to a top surface of the diamond, and cut the diamond with the laser beam parallel to a bottom surface of the diamond; after the edging, for the slicing: reposition the article in the second orientation; cut the article with the laser beam along a third side of the diamond perpendicular to the first side and the second side to remove a third graphitized slice; and cut one or more thin slices from the diamond with the laser beam, wherein each thin slice is cut parallel to the cutting along the third side, and wherein a last thin slice is cut along a fourth side of the diamond opposite to the third side.

[0052] In an implementation form of the apparatus of the second aspect, the apparatus further comprises a holder configured to hold a plurality of CVD diamond articles arranged successively in a determined direction.

[0053] The holder enables successive coring, (optionally edging) and slicing of a plurality of CVD diamond articles, thus resulting in an efficient process. For example, the holder can hold 5-15, in particular 8-10 CVD diamond articles.

[0054] In an implementation form of the apparatus of the second aspect, the holder comprises an elongated metal sheet and a plurality of holding portions arranged along the holder in the determined direction, wherein each holding portion comprises a cut-out of the metal sheet and one or more attachment tabs for attaching an article, in particular by means of adhesive, such that the article is positioned within the cut-out in a determined orientation.

[0055] In an implementation form of the apparatus of the second aspect, the holder is only attached to (e.g. glued to) graphitized material during the entire coring and slicing of the article. Thus, no glue is left on the wafer after production of the wafer.

[0056] In an implementation form of the apparatus of the second aspect, the machining unit comprises a rotatable element, and the holder is easily attachable to and detachable from the rotatable element.

[0057] In an implementation form of the apparatus of the second aspect, the apparatus further comprises an optical sensor configured to determine whether the laser beam has penetrated the article during cutting of the article.

[0058] In an implementation form of the apparatus of the second aspect, the optical sensor is configured to receive laser-induced electromagnetic radiation propagating out of the article, in particular radiation from a plasma formed at a surface of the article by cutting the article with the laser beam; convert the received radiation into a signal; and determine, based on the signal, whether the laser beam has penetrated the article; wherein the optical sensor is in particular arranged to receive the radiation through the fluid jet.

[0059] In an implementation form of the apparatus of the second aspect, the apparatus further comprises a distance sensor configured to measure a surface orientation of a top surface and / or a bottom surface of the diamond; and the control unit is configured to determine, based on the measured surface orientation, the second orientation and / or a slicing direction for the wafer.

[0060] The apparatus enables the method of the first aspect, thus all the advantages described above.

[0061] A third aspect of the present application provides a computer program (or computer program product) comprising program code which, when executed by a processor, is configured to control an apparatus according to the second aspect and any implementation form thereof, in particular to control the control unit, or to perform the method according to the first aspect or any implementation form thereof.

[0062] A fourth aspect of the present application provides a non-transitory storage medium storing executable program code which, when executed by a processor, causes the method according to the first aspect or any implementation form thereof to be performed. BRIEF DESCRIPTION OF DRAWINGS

[0063] The above aspects and implementation forms defining the general implementation form according to the present application are explained in the following description of specific embodiments related to the enclosed drawings, in which:

[0064] Figure 1 A method according to an embodiment of the present application is shown, as well as a device performing the method according to an embodiment of the present application is shown schematically.

[0065] Figure 2 A schematic flow chart of a method according to an embodiment of the present application is shown.

[0066] Figure 3 Details of a device according to an embodiment of the present application are shown.

[0067] Figure 4 Steps of an exemplary method according to an embodiment of the present application are shown.

[0068] Figure 5 Further steps of an exemplary method are shown.

[0069] Figure 6 Further steps of an exemplary method are shown.

[0070] Figure 7 Further steps of an exemplary method are shown.

[0071] Figure 8 Further steps of an exemplary method are shown.

[0072] Figure 9 Further steps of an exemplary method are shown.

[0073] Figure 10 A holder for a CVD diamond article used in a method according to an embodiment of the present application is shown.

[0074] Figure 11 Alternative CVD diamond article types and alternative holders and exemplary methods are shown. DETAILED DESCRIPTION

[0075] Figure 1 A method 10 according to an embodiment of the application is schematically illustrated. The steps of the method 10 are illustrated in the flowchart of Figure 2 The method 10 is suitable for coring 21 and slicing 22 a CVD diamond article 11. Such a CVD diamond article comprises a diamond 11a and a graphitized material 11b covering a plurality of sides of the diamond 11a. For example, the crystalline diamond 11a can be a rectangular diamond or a cubic diamond (e.g. between 5x 5x 5mm and 20x 20x 20mm), and the graphitized material 11b can cover four sides of the diamond 11a. Each side of the diamond 11a can be covered by a thick mass of unwanted graphitized material, which typically consists of a composite of diamond crystallites and graphite. The top and bottom faces of such a rectangular or cubic diamond 11a can not be covered by the graphitized material 11b, or can not be covered by a thick mass of graphite but only by a small layer of graphitized material 11b.

[0076] The method can be performed by an apparatus 30 according to an embodiment of the application, which is schematically illustrated in Figure 1 or in more, optional, detail in Figure 3 The apparatus 30 is configured to provide a laser beam 14 coupled into a pressurized fluid jet 13, i.e. to provide a fluid jet guided laser beam. The fluid jet 13 can comprise a liquid jet, in particular a water jet.

[0077] The method 10 comprises a step 21 of coring the CVD diamond article 11, wherein the article 11 is cut by the laser beam 14 of the apparatus 30 to remove the graphitic material 11b from the sides of the diamond 11a. The method 10 further comprises a step 22 of slicing the CVD diamond article 11, wherein one or more thin slices 12 are cut from the diamond 11a using the laser beam 14 of the apparatus. The slicing step 22 can, but does not have to, be performed after the coring step 21. For example, the coring step 21 and the slicing step 22 can be performed alternately, e.g. first the graphitic material 11b can be removed from one or more sides of the diamond 11a, then the diamond 11a can be sliced, and then the graphitic material can be removed from the remaining sides of the diamond 11a.

[0078] For example, 5 to 20, in particular 10 to 15, thin slices 12 can be cut from the diamond 11a. Thereby, the thickness of each slice can be in the range of only 0.1 - 0.4 mm, in particular in the range of 0.2 - 0.3 mm. Further, the average surface roughness of the slice surface 12 (cut surface of the slice 12) can be in the range of only 200 - 600 nm, in particular in the range of 300 - 500 nm. The cutting of the diamond 11 can be performed along one or more determined crystal diamond orientations to obtain the slices 12. The slices 12 can be completely parallel to each other. Overall, the quality of the diamond slices is thus very high.

[0079] The cutting of the graphitized material 11b or the diamond 11a can be performed by multi-pass cutting. That is, for each cut performed along a cutting path (e.g. straight and / or along a determined crystal diamond orientation), it can be performed by moving the laser beam 14 back and forth along the path quickly. Thus, the laser beam 14 can be displaced at high speed relative to the article 11. Overall, the coring 21 and slicing 22 can thus be performed quickly.

[0080] In particular, the method 10 is performed automatically and / or seamlessly, in particular by the device 30. The method 10 is further performed in a single process, in particular by the device 30. Thus, the method 10 can be performed efficiently and quickly.

[0081] Further, for a particular step of the method 10, the article 11 can be positioned in a plurality of particular orientations, e.g. a plurality of different orientations. For example, for the coring 21, the article 11 can be positioned in a first orientation, and for the slicing 22, the article 11 can be positioned in a second orientation. Thereby, the second orientation for the slicing 22 can be tilted relative to the first orientation for the coring 21. For example, the second orientation for the slicing 22 can be tilted by 5° to 20°, in particular 10° to 15°, relative to the first orientation for the coring 21.

[0082] Figure 3 A device 30 according to an embodiment of the present application is shown. The device 30 is configured to core and slice a CVD diamond article 11, as Figure 1 or Figure 2 indicated, i.e. the device 30 can be used in the method 10. The device 30 comprises at least a machining unit 31, a control unit 32. The device 30 can further comprise an optical sensor 33a, a distance sensor 33b, and can further optionally comprise further elements and units described below.

[0083] The machining unit 31 is configured to provide the laser beam 14 coupled into the pressurized fluid jet 13. The control unit 32 is configured to control the machining unit 31. In particular, the control unit 32 can control the machining unit 31 to, for performing the coring 21, cut the article 11 with the laser beam 14 to remove graphitized material 11b from the side of the diamond 11a, and to, for performing the slicing 22, cut one or more thin slices 12 from the diamond 11a with the laser beam 14. These actions can implement the method 10 shown in Figure 1 and Figure 2 Optional optical sensors 33a can be configured to determine, for one or more cuts or for each cut, during the coring 21 and slicing 22 of the article 11, whether the laser beam 14 has penetrated the article 11. Thus, the overall processing speed can be significantly improved. Distance sensors 33b can be configured to measure the surface orientation of the top and / or bottom surface of the diamond. Then, the control unit 32 can determine a (best) second orientation for slicing and / or can determine a (best) slicing direction based on the measured surface orientation to achieve the most efficient slicing.

[0084] The machining unit 31 can couple the laser beam 14 into the fluid jet 13, the laser beam 14 being received, for example, from one laser source 35, which can optionally be part of the apparatus 30, or the laser beam 14 being received, for example, from a plurality of laser sources 35. The coupling can be done in the machining unit 31. In particular, the machining unit 31 can comprise optical elements, like at least one lens 36, for coupling the laser beam 14 into the fluid jet 13. The laser beam 14 can be generated outside the machining unit 31 and can be injected into the machining unit 31. In the machining unit 31, a mirror, and / or a beam splitter 37, and / or another optical element can direct the laser beam 14 towards, for example, the at least one lens 36. The beam splitter 37 can also be used to couple a portion of the laser light, or electromagnetic radiation from the article 11, to the optical sensors 33a. The machining unit 31 can further comprise an optically transparent protective window 39 to separate the optical arrangement, here exemplified as the optical elements 36, from the fluid circuit, for example, the water circuit, and from the region of the machining unit 31 where the fluid jet 13 is generated.

[0085] To generate the fluid jet 13, the machining unit 31 can comprise a fluid jet generating nozzle 38 having a hole of a certain size. The fluid jet generating nozzle 38 can be arranged within the machining unit 31 to generate the fluid jet 13 in a protected environment. The hole can define a width of the fluid jet 13. The diameter of the hole can be for example 10-200 pm, and the diameter of the fluid jet 13 can be for example about 0.6-1 times the diameter of the hole. The pressure of the pressurized fluid jet 13 can be provided by an external fluid supply 34, which is typically not part of the device 30 (but can also be). The pressure can be for example 50-800 bar. To output the fluid jet 13 from the device 30, the machining unit 31 can comprise an outlet nozzle having an outlet hole. In particular, the outlet hole is wider than the hole of the fluid nozzle.

[0086] The control unit 32 can also control the at least one laser source 35 (e.g. the control unit 32 can command a laser controller of the laser source 35). That is, the control unit 32 can instruct the laser controller of the laser source 35 to output a respective laser emission. Thereby, the laser controller of the laser source 35 can set a constant laser beam or a pulsed laser beam according to the instructions of the control unit, in particular for a pulsed laser beam, the pulse power, the pulse width, the pulse repletion rate, the pulse burs rate, or the pause between pulses can be set. For example, for coring 21 and slicing 22, the pulse intensity of the laser beam 14 can be in the range of 0.8-2 GW / cmA2, and / or the pulse power of the laser beam 14 can be in the range of 20-300 W, and the pulse length of the laser beam 14 can be in the range of 150-400 ns. The control unit 32 can also control the fluid supply 34.

[0087] During coring 21 and slicing 22, the CVD diamond article 11 can be held by a certain holder 100 (described in more detail in Figure 10 ). The holder 100 can or can not be part of the device 30. In either case, the device 30 can be arranged such that the device 30 is able to machine the CVD diamond article 11 held by the holder 100. The holder 100 can be attached to the rotatable element 131 of the device 30. The device 30, in particular the control unit 31, can thereby control the holder 100 (in particular the rotatable element 131) in up to three dimensions (e.g. as described in more detail in Figure 3The holding member 100 can also be rotated by the device 30 rotating the rotatable element 131. In particular, the device 30 can then cut the CVD diamond article 11 by moving the fluid jet guided laser beam 14 above the article 11 along a cutting path, in particular a two-dimensional path, such as a straight line and / or an arc. Thereby, a multi-pass cutting as described above can be performed. Thereby, the movement can also be continuous or step-wise and the movement speed can be selected / changed.

[0088] The rotatable element 131 can be driven by a motor or a CNC. For example, the rotatable element 131 of the device 30 can be a rod or a so-called “Dop (diamond clamp)”. By the rotatable element 131, the article 11 can be repositioned relative to the laser beam 14, i.e. the orientation of the article 11 can be changed. In particular, the above-mentioned first and second orientations can be set. The rotatable element 131 (diameter / width) can be at least 10% smaller, in particular at least 20% smaller than the diameter of the article 11. The rotatable element 131 can be rotatable around a rotation axis (e.g. shown) which can be parallel to the z-direction. The rotation of the rotatable element 131 can be controlled by the control unit 32, in particular based on input from the optical sensor 33a. Figure 3

[0089] The optical sensor 33a can be arranged to receive laser-induced electromagnetic radiation propagating out of the article 11 (e.g. when cutting the article 11 with the laser beam 14), e.g. through the fluid jet 13 and further through the at least one optical element 36, 37 to the optical sensor 33a. In particular, the optical sensor 33a can be arranged to receive laser-induced electromagnetic radiation through the fluid jet 13 and through the at least one optical element 36, the optical element 36 being configured to couple the laser beam 14 into the fluid jet 13. The laser-induced electromagnetic radiation can include secondary radiation emitted from a portion of the article 11 cut with the laser beam 14. For example, the laser-induced electromagnetic radiation can be induced due to a cut surface area of the workpiece turning into a plasma. This plasma can emit characteristic radiation which can be readily on or isolated by the optical sensor 33a. The laser-induced electromagnetic radiation can also include primary laser radiation reflected from the article 11. The laser-induced electromagnetic radiation can also include secondary radiation resulting from scattering, preferably Raman scattering, of the laser beam 14 in the fluid jet 13.

[0090] ​The distance sensor 33b can be a second optical sensor (i.e. in addition to the optical sensor 33a). In this case, the distance sensor 33b can be arranged to optically measure the surface orientation of the article 11, e.g. by measuring the light reflected from the article 11. To this end, the distance sensor 33b can also be configured to emit light onto the article 11. The distance sensor 33b can also be a touch probe. In this case, the distance sensor 33b can be arranged such that it can touch the article 11 to perform the surface orientation measurement, or the distance sensor 33b can be configured such that it can be moved towards the article 11 to perform the measurement.

[0091] The optical sensor 33a and / or the distance sensor 33b can be arranged in the machining unit 31. However, the optical sensor 33a can also be arranged in the laser source 35. In this case, the laser-induced radiation can be back-propagated from the article 22 and can be guided through the machining unit 31 to the laser source 35, where it is received by the optical sensor 33a. For example, the machining unit 31 can be optically connected to the laser source 35 by an optical fiber.

[0092] The optical sensor 33a can also be configured to convert the received radiation into a signal. The control unit 32 can comprise a processing circuitry configured to determine, based on the signal, a state of machining / cutting the article 11. The state of machining the article 11 can be whether the laser beam 14 has penetrated the article 11, i.e. whether the graphitized material 11b and / or the diamond 11a has been penetrated. In particular, the control unit 32 can be configured to determine whether the performed cutting of the graphitized material 11b or the diamond 11a is complete, or whether the performed cutting is incomplete, and / or whether the graphitized material 11b or the diamond 11a has not been removed at all by performing the cutting.

[0093] The apparatus 30, in particular the control unit 32, can comprise a processor or processing circuitry (not shown) configured to perform, implement or initiate the various operations of the apparatus 30 described herein, in particular to perform the method 10. The processing circuitry can comprise hardware and / or the processing circuitry can be controlled by software. The hardware can comprise analog circuitry or digital circuitry, or both analog circuitry and digital circuitry. The digital circuitry can comprise components such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), or a multi-purpose processor.

[0094] Apparatus 30 may further include memory circuitry storing one or more instructions executable by a processor or processing circuitry, particularly under software control. For example, the memory circuitry may include a non-transitory storage medium storing executable software code or program code that, when executed by a processor or processing circuitry, causes various operations of the apparatus described herein, particularly causing execution method 100.

[0095] Figure 4-9 An exemplary method 10 according to an embodiment of the present invention is shown, which can utilize Figure 3 The device 30 shown is executed.

[0096] Figure 4 (a) shows that initially the CVD diamond article 11 can be attached to the retainer 100 (regarding...). Figure 10 (In more detail), the retainer 100 may be part of the device 30, or may be attached to the device 30, for example, to the rotatable element 131. The article 11 may be attached to the retainer 100 solely by the graphitized material 11b. In particular, the retainer 100 may be attached solely to the graphitized material 11b throughout the entire core extraction 21 and slicing 22 of the article 11. The article 11, and especially the graphitized material 11b, may be adhered to the retainer 100, for example, to the retaining portion of the retainer 100.

[0097] Figure 4 (b) illustrates the first cutting step for performing core extraction 21. Specifically, the article 11 can be cut along the first side of the diamond 11a using the laser beam 14 to remove the first graphitized sheet, and the second side of the diamond 11a opposite to the first side can be cut to remove the second graphitized sheet. Figure 4 The dashed line in (b) represents the path of laser beam 14. Figure 4 In this diagram, the laser beam 14 extends exemplarily into the plane of the diagram, i.e., parallel to the first and second side surfaces. Specifically, Figure 4 The cutting shown in (b) can be performed on the first orientation of the article 11, i.e., the article 11 can be positioned in the first orientation, wherein the orientation is relative to the laser beam 14.

[0098] Figure 5 (a) shows in Figure 4 (b) The product 11 after the cutting step. It can be seen that the graphitized material 11b has been removed from the two opposite sides of the diamond 11a. Figure 5 (a) shows that article 11 can then be repositioned. In particular, in this example, article 11 is repositioned to a third orientation.

[0099] In this example, the article 11 is rotated about 90° from the first orientation used for coring 21 to a third orientation. Figure 6 (a) shows the article 11 in the third orientation after rotation.

[0100] Figure 6 (b) shows that a step of trimming 23 of the CVD diamond article 11 can be performed in the third orientation. The trimming 23 of the article 11 is an optional step of the method 10. The trimming 23 of the article 11 can comprise cutting the diamond 11a parallel to the top face of the diamond 11a with the laser beam 14 and cutting the diamond 11a parallel to the bottom face of the diamond 11a with the laser beam 14, as indicated by the dashed lines showing the cutting paths of the laser beam 14. The trimming 23 can remove the graphitization layer present on the top face and / or the bottom face. The trimming 23 can comprise cutting the top face and / or the bottom face of the diamond 11a such that all the faces of the diamond 11a, i.e. the side faces as well as the top and bottom faces, have a determined size. All the faces can in particular have the same 2D size.

[0101] Figure 6 (c) shows that the article 11 can then be repositioned. In particular, in this example, the article 11 can be repositioned into a second orientation for slicing 22. In particular, in this example, the article 11 can be rotated back about 90° (the angle by which the article 11 was rotated from the first orientation used for coring 21) from the third orientation used for trimming 23 to the second orientation for slicing 22.

[0102] Figure 7 (a), Figure 8 (a) and Figure 8 (b), and Figure 9 (a) shows the step of slicing 22 of the diamond 11a. In particular, the slicing 22 can comprise cutting the article 11 along a third side face of the diamond 11a perpendicular to the first and second side faces with the laser beam 14 to remove a third graphitized sheet. This is shown in Figure 7 and by the dashed lines showing the paths used for cutting by the laser beam 14.

[0103] The slicing 22 can further comprise cutting one or more lamellas 12 from the diamond 11a with the laser beam 14. The thickness of each lamella can be in the range of 0.1-0.4 mm. This is shown in Figure 7 (b), Figure 8 (a) and Figure 8 (b), and Figure 9 (a) shows that a total of 5 lamellas are to be removed as an example. However, typically even 10 to 20, e.g. 15, lamellas 12 are cut from the diamond 11a. Each lamella 12 can be cut parallel to the cutting along the third side face, i.e. each lamella 12 is further cut parallel to the next lamella 12. As Figure 9(a) shows that the last wafer 12 can be cut along a fourth side of the diamond 11a, which is opposite to the third side.

[0104] Figure 9 (b) shows that after slicing 22 of the diamond 11a only the graphitized sheet is left which is attached to the holder 100. The cored diamond 11a is completely sliced into wafers 12. The figure also shows that a further CVD diamond article can be cored and sliced subsequently. In particular, the method 10 can also comprise successively coring 21 and slicing 22 each of one or more further articles in the same way as the first CVD article 11 is cored and sliced. For this purpose, a plurality of CVD articles 11 can be held on the particular holder 100 which is described next.

[0105] Figure 10 A holder 100 is shown which can be part of the device 30 and / or can be easily attached to and detached from the rotatable element 131 of the device 30. The holder 100 is configured to hold a plurality of CVD diamond articles 11 which are arranged successively in a determined direction, in particular. For example, as shown, the holder 100 can comprise an elongated metal sheet and a plurality of holding portions arranged along the holder 100 in the determined direction, wherein the CVD articles 11 are held in the respective holding portions. As an example, each holding portion can comprise a cut-out 101 of the metal sheet and one or more attachment tabs 102, e.g. protruding into each cut-out 101, for attaching the CVD diamond article 11, in particular by gluing 40. Thereby, the article 11 is positioned within the cut-out 101. In particular, as already described above, the holder 100 is only attached to the graphitized material 11b.

[0106] Figure 11 A further exemplary method 10 according to an embodiment of the present application is shown which can be performed with the device 30 shown. Figure 3

[0107] In particular, Figure 11 In (a) a CVD diamond article 11 is shown which comprises a diamond 11 and a graphitized material 11b. In this exemplary CVD diamond article 11, the graphitized material 11b is deposited parallel to a side of the diamond 11.

[0108] Further, Figure 11 ​An exemplary method 10 for coring and slicing the article 11 shown in (a) is shown in (b) and (c). The device 30 for coring and slicing the article 11 comprises one or more diamond holder holders 110. Two diamond holder holders 110 are exemplarily shown, but the device 30 can have a plurality (more than two) of diamond holder holders. Each diamond holder holder 110 can hold one article 11, so that a plurality of articles 11 can be processed (coring and slicing) successively. The top or bottom face (on which there is no thick graphitized material) of each article 11 can be attached to the respective diamond holder holder 110. Each diamond holder holder 110 can comprise an elongated shaft, and each diamond holder holder 110 can be configured to be rotated about an axis extending along the elongation direction of the shaft. That is, each diamond holder holder 110 can be rotated about itself.

[0109] Figure 11 It is shown in (a) that the graphitized material 11b can first be removed from the side faces of the diamond 11 by cutting with the laser beam 14 directed in the fluid jet 13. As shown, the cutting can be performed parallel to the respective side face. After each cutting, the respective diamond holder holder 110 can be rotated to prepare for the next cutting, for example, it can be rotated by 90° about the axis.

[0110] Figure 11 It is also shown in (b) that the cored diamond 11a can then be sliced by cutting with the laser beam 14 parallel to the top or bottom face of the cored diamond 11a (depending on whether the top or bottom face of the diamond 11a is attached to the diamond holder holder 110). That is, the slicing can be performed parallel to the diamond seed surface.

[0111] Thus, Figure 11 The method 10 can be performed with the same parameters (laser beam 14, fluid jet 13, displacement speed, etc.) as described for the method 10 for Figure 2 or Figure 4-9 The method 10.

[0112] The application has been described in relation to various embodiments and implementation forms as examples. However, other variants can be understood and implemented by a person skilled in the art, practicing the claimed embodiments, by studying the attached drawings, the description and the independent claims. In the claims and in the description, the expression “comprises” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit can implement the functions of several entities or items recited in the claims. Indeed, certain measures recited in mutually different dependent claims do not indicate that a combination of these measures cannot be used to advantage.

Claims

1. A method (10) for coring (21) and slicing (22) a chemical vapor deposition, CVD, diamond article (11), the article (11) comprising diamond (11a) and graphitized material (lib) covering a plurality of sides of the diamond (11a), wherein, The method (10) is performed by a device (30) that provides a laser beam (14) coupled into a pressurized fluid jet (13), and wherein the method (10) comprises: - to perform the coring (21), cutting the article (11) with the laser beam (14) to remove the graphitized material (11b) from sides of the diamond (11a); - to perform the slicing (22), cutting one or more wafers (12) from the diamond (11a) with the laser beam (14).

2. The method (10) of claim 1, wherein: to perform the coring (21), the article (11) is positioned in a first orientation, and to perform the slicing (22), the article (11) is positioned in at least a second orientation.

3. The method (10) of claim 2, further comprising: measuring a surface orientation of a top surface and / or a bottom surface of the diamond (11a); and determining the second orientation and / or a slicing direction for the slicing based on the measured surface orientation.

4. The method (10) of claim 2, wherein: the first orientation for the coring (21) is the same as the second orientation for the slicing (22); or the second orientation for the slicing (22) is tilted 5°-20° relative to the first orientation for the coring (21); or the second orientation for the slicing (22) is rotated 90° relative to the first orientation for the coring.

5. The method of claim 2, wherein: the slicing comprises positioning the article (11) in the second orientation to initiate cutting a set of wafers from the diamond (11a), and rotating the article 180° to complete cutting the set of wafers from the diamond (11a).

6. The method (10) of claim 2, further comprising: dressing (23) the CVD diamond article (11) by cutting the diamond (11a) with the laser beam (14) parallel to a top surface and / or a bottom surface of the diamond (11a); wherein to perform the dressing (23), the article (11) is positioned in a third orientation.

7. The method (10) according to claim 6, wherein The method (10) comprises: to perform the coring (21): - cutting the article (11) with the laser beam (14) along a first side of the diamond (11a) to remove a first graphitized slice; and - cutting the article with the laser beam (14) along a second side of the diamond (11a) opposite the first side to remove a second graphitized slice; after the coring (21), to perform the dressing (23): - repositioning the article (11) in the third orientation; - cutting the diamond (11a) with the laser beam (14) parallel to a top surface of the diamond (11a), and cutting the diamond (11a) with the laser beam (14) parallel to a bottom surface of the diamond (11a); After the trimming (23), for performing the slicing (22): - repositioning the article (11) into the second orientation; - cutting the article (11) along a third side of the diamond (11a) perpendicular to the first and second sides with the laser beam (14) to remove a third graphitized sheet; and - cutting one or more wafers (12) from the diamond (11a) with the laser beam (14), wherein each wafer (12) is cut parallel to the cutting along the third side, and wherein a last wafer (12) is cut along a fourth side of the diamond (11a) opposite the third side.

8. The method (10) according to claim 6, further comprising: rotating the article (11) 90° from the first orientation for the coring (21) to the third orientation for the trimming (23); and rotating the article back 90° from the third orientation for the trimming (23) to the second orientation for the slicing (22) or keeping the third orientation for the slicing (22).

9. The method (10) according to claim 6, wherein: trimming (23) the article (11) comprises cutting a top and a bottom face of the diamond (11a) such that all faces of the diamond (11a) have a determined size and orientation.

10. The method (10) according to any one of claims 1 to 9, wherein: the slicing comprises cutting the one or more wafers (12) from the diamond (11a) parallel to a top and / or bottom face of the diamond (11a).

11. The method (10) according to any one of claims 1 to 9, further comprising: successively coring (21) and slicing (22) each of one or more further articles in the same way as the article (11).

12. The method (10) according to any one of claims 1 to 9, wherein: the method (10) is performed automatically and / or continuously by the device (30); and / or the method (10) is performed by the device (30) in a single process.

13. The method (10) according to any one of claims 1 to 9, wherein: an average surface roughness of a cut surface of the wafer (12) is in the range of 200-600 nm.

14. The method (10) according to any one of claims 1 to 9, wherein: a kerf created by cutting with the laser beam (14) is in the range of 25-100 pm; and / or a taper created by cutting with the laser beam (14) is in the range of 1°-2°.

15. The method (10) according to any one of claims 1 to 9, wherein: cutting the diamond (11a) comprises cutting along a determined crystal orientation of the diamond (11a).

16. The method (10) according to any one of claims 1 to 9, wherein: the laser beam (14) is a pulsed laser beam, and the laser beam (14) is a continuous wave laser beam. The pulse intensity of the laser beam (14) in the fluid jet (13) is in the range of 0.8 - 2.0 GW / cm 2 and / or The average power of the laser beam (14) is in the range 20-300 W, and the pulse length of the laser beam (14) is in the range 150-400 ns.

17. The method (10) of claim 1, further comprising: receiving, by the device (30), laser-induced electromagnetic radiation propagating out of the article (11) during cutting of the article (11); converting the received radiation into a signal; and determining, based on the signal, whether the laser beam (14) has penetrated the article (11).

18. The method (10) of claim 17, wherein: the laser-induced electromagnetic radiation is received, by the device (30), through the fluid jet (13).

19. A device (30) for coring (21) and slicing (22) a chemical vapor deposition, CVD, diamond article (11), the CVD diamond article (11) comprising a diamond (11a) and a graphitized material (11b) covering a plurality of sides of the diamond (11a), the device (30) comprising: a machining unit (31) configured to provide a laser beam (14) coupled into a pressurized fluid jet (13); and a control unit (32) configured to control the machining unit (31) to: - for performing the coring (21), cut the article (11) with the laser beam (14) to remove the graphitized material (11b) from sides of the diamond (11a); - for performing the slicing (22), cut one or more thin slices (12) from the diamond (11a) with the laser beam (14).

20. The device (30) of claim 19, wherein: the control unit (32) is further configured to, for performing the coring (21), position the article (11) in a first orientation, and to, for performing the slicing (22), position the article (11) in at least a second orientation.

21. The apparatus (30) of claim 20, wherein, the control unit (32) is further configured to control the machining unit (31) to: trim (23) the CVD diamond article (11) by cutting the diamond (11a) with the laser beam (14) parallel to a top and / or bottom face of the diamond (11a); wherein, for performing the trimming (23), the article (11) is positioned in a third orientation.

22. The apparatus (30) of claim 21, wherein the control unit (32) is configured to control the machining unit (31) to: for performing the coring (21): - cut the article (11) with the laser beam (14) along a first side of the diamond (11a) to remove a first graphitized slice; and - cut the article (11) with the laser beam (14) along a second side of the diamond (11a) opposite the first side to remove a second graphitized slice; after the coring (21), for performing the trimming (23): - reposition the article (11) in the third orientation; - cutting the diamond (11a) with the laser beam (14) parallel to a top face of the diamond (11a), and cutting the diamond (11a) with the laser beam (14) parallel to a bottom face of the diamond (11a); after the trimming (23), in order to perform the slicing (22): - repositioning the article (11) into the second orientation; - cutting the article (11) with the laser beam (14) along a third side of the diamond (11a) perpendicular to the first and second sides to remove a third graphitized sheet; and - cutting one or more wafers (12) from the diamond (11a) with the laser beam (14), wherein each wafer (12) is cut parallel to the cutting along the third side, and wherein a last wafer (12) is cut along a fourth side of the diamond (11a) opposite the third side.

23. The apparatus (30) according to claim 19, further comprising: a holder (100) configured to hold a plurality of CVD diamond articles (11) arranged successively in a determined direction.

24. The apparatus (30) according to claim 23, wherein: the holder (100) comprises an elongated metal sheet and a plurality of holding portions arranged along the holder (100) in the determined direction, wherein each holding portion comprises a cutout (101) of the metal sheet and one or more attachment tabs (102) for attaching an article (11) such that the article (11) is positioned within the cutout (101) in a determined orientation.

25. The apparatus (30) according to claim 23, wherein: the holder (100) is attached only to graphitized material (11b) during the entire coring (21) and slicing (22) of the article (11).

26. The apparatus (30) according to any one of claims 23 to 25, wherein: the machining unit (31) comprises a rotatable element (131), and the holder (100) is susceptible of being attached to and detached from the rotatable element (131).

27. The apparatus (30) according to claim 19, further comprising: an optical sensor (33a) configured to determine, during cutting of the article (11), whether the laser beam (14) has penetrated the article (11).

28. The apparatus (30) according to claim 27, wherein: the optical sensor (33a) is configured to receive laser-induced electromagnetic radiation propagating out of the article (11); convert the received radiation into a signal; and determine, based on the signal, whether the laser beam (14) has penetrated the article (11); wherein the optical sensor (33a) is arranged to receive the radiation through the fluid jet (13).

29. The apparatus (30) according to claim 20, further comprising: a distance sensor (33b) configured to measure a surface orientation of a top surface and / or a bottom surface of the diamond (11a); and the control unit (32) is configured to determine the second orientation and / or slicing direction for the slice based on the measured surface orientation.

30. A non-transitory storage medium storing executable program code which, when executed by a processor, causes performance of the method according to any one of claims 1 to 18.

Images