The invention relates to a method for the manufacture of a component of a CVD reactor, which consists of quartz and has at least one cavity.
The invention relates to a use of a component produced from a quartz blank.
A gas inlet unit made of quartz is described in DE 10 2008 055 582 A1. The gas inlet unit there described has a central body, which is arranged around a figure axis of the gas inlet unit. In the central region of the gas inlet unit extend a plurality of gas inlet ducts, arranged concentrically with respect to each other, which open into outlets extending over an entire peripheral length. The outlets of the gas inlet ducts are adjoined by gas distribution chambers surrounding the central section in an annular shape, which are separated by dividing floors into a plurality of gas distribution levels arranged one above another. The radially outer edge of each of the gas distribution chambers is surrounded by a gas distribution wall, which has a multiplicity of gas passage openings, which open into gas outlet openings, through which process gases can be fed into a process chamber of a CVD reactor. Each of the plurality of gas distribution chambers can be fed with an individual gas mixture of a process gas, so that the process gases can flow at levels that differ from each other into a process chamber adjoining the gas inlet unit. In the process chamber, substrates lie on a susceptor heated from underneath, and can be coated with III-V-layers, or with IV-layers, or with II-VI-layers.
Methods for the structuring of quartz bodies are of known art from DE 100 29110 B4, EP 3 036 061 B1, DE 20 2017 002 851 U1 and DE 10 2018 202 687 A1. A quartz blank with a polished surface is first treated with a laser beam. Here the laser beam generates ultra-short pulses and is focused. The focal point is moved in a writing motion, for example line-by-line, through the volume of the quartz blank. At the focal point, the laser beam reaches an intensity above a threshold intensity at which a material transformation takes place in the quartz material. The transformed material can then be removed with a fluid etchant, for example a potassium hydroxide solution. It is known from the prior art to use this method to produce liquid channels for the nozzle bodies of spray heads or spray cans. It is also of known art to produce cavity structures in components for a projection lighting system. It is also known in the art to use this method, known as SLE (selective laser-induced etching), to produce microchannels, shaped holes, and contoured cuts in transparent components made of quartz glass, borosilicate glass, sapphire and ruby.
The prior art also includes the article “Selective, Laser-Induced Etching of Fused Silica at High Scan-Speeds Using KOH, JLMN Journal of Laser Micro/Nanoengineering, Vol. 9, No. 2, 2014, pp. 126-131”, as well as DE 102 47 921 A1, DE 10 2010 000 554 A1, DE 10 2014104 218 A1, DE 20 2017 005165 U1 and DE 20 2018 003 890 U1, and the article “Selective Laser-Induced Etching of 3D Precision Quartz Glass Components for Microfluidic Applications—Up-Scaling of Complexity and Speed, Micromachines, Vol. 8(4), 2017, No. 110, pp. 1-10”.
The objective underlying the invention is that of the specification of a method with which, in particular, components of a CVD reactor of complex design can be produced from quartz, as well as the specification of such a quartz component.
The objective is achieved by the invention specified in the claims, wherein the subsidiary claims represent not only advantageous further developments of the invention indicated in the respective independent claims, but also autonomous solutions of the object.
The quartz component of a CVD reactor according to the invention has cavities that are produced by selective laser-induced etching (SLE). In this method, a local material transformation of the initial homogeneous quartz body is carried out in a first process step. For this purpose, an ultra-short pulsed laser beam is focused at a focal point in the micrometer range, wherein the focal point is guided through the volume of the quartz body by a three-dimensional movement of the laser beam relative to the quartz workpiece. First, a solid quartz body is produced, which can have a polished surface. A focused laser beam is used to expose volumetric regions that are distant from the surface. A material transformation of the quartz material takes place at the focal point of the laser beam by way of a multi-photon process. The material thus transformed can be removed in a second process step using an etching fluid. The etching fluid preferably takes the form of a liquid, for example KOH. Inventive components of a CVD reactor are to be produced using this method, which is known in the art per se. For example, the gas distribution wall, its gas passage openings, the central plinth, its gas supply lines, and the flow barrier extending between the central section and the gas distribution wall, including its passage opening, can be produced in a disc-shaped quartz base body with this method. The disc-shaped gas distribution bodies/sections produced in such a materially integral manner can then be stacked one on top of another, and, in particular, joined to one another by means of material bonding. In a particularly preferred variant of the invention, the gas distribution bodies are connected to one another in a materially integral manner. The SLE method described above is also used for the manufacture of such an integral gas inlet unit, produced from a uniform quartz blank. The method according to the invention can be used in particular to produce those components of a CVD reactor that cannot be produced by other shaping processes, for example by casting, blow moulding, or machining. The components produced according to the invention can have complex cavity shapes, and are capable of being used at temperatures above 500° C. in a CVD reactor, wherein they come into contact with hydrides of the IV-, V-, or VI-main group, or with organometallic compounds, or halogens of elements of the II-, III-, or V-main group. The inventive quartz components are, in particular, substrate carriers, gas outlet units, gas inlet units, shield plates, susceptors, light passage plates, sheaths, or cover plates, wherein, in particular, provision is made for these components to have cavity arrangements, which have a multiplicity of gas passage openings, which extend between two surfaces of the component, and are arranged in an essentially uniform manner on a gas outlet surface. Such components serve in particular the purpose of generating a homogeneous gas flow in a process chamber of a CVD reactor, for which purpose the gas outlet openings of a gas outlet surface, that is to say, the free ends of the gas passage holes, are uniformly distributed over a surface. The gas passage holes can have a diameter that is smaller than 0.1 mm. However, provision is also made for the gas passage holes to have a diameter that is smaller than 3 mm, 2 mm, 1 mm, 0.5 mm, or 0.2 mm. Furthermore, provision is preferably made for the component to have a cavity that is formed by at least one large chamber, which forms a gas distribution chamber. The gas distribution chamber branches into a multiplicity of gas passage holes, so that gas outlet openings can communicate with one common gas distribution chamber, or with a plurality of gas distribution chambers. At least one gas supply line opens into the gas distribution chamber. In particular, provision is made for an inner surface of the gas distribution chamber to be designed in a materially integral manner, and to be interrupted only by the outlet of the at least one gas supply line and the openings of the gas passage holes. Provision can thus be made for a gas supply line with a small free flow cross-sectional area to open into a gas distribution chamber that has a large free cross-sectional area, wherein the free cross-sectional area extends at right angles to the direction of flow. The free cross-sectional area of the gas distribution chamber can be at least ten times, preferably twenty times, larger than the free cross-sectional area of the at least one gas supply line, or the sum of the free cross-sectional areas of a plurality of gas supply lines. Provision is furthermore made for the free cross-sectional area of the gas distribution chamber, extending transversely to the flow through the component, to be at least twice, five times, ten times, preferably at least twenty times, at least fifty times, or at least one hundred times, as large as the sum of the free cross-sectional areas of the gas passage holes leading out of the gas distribution chamber. In particular, provision can furthermore be made for the gas passage holes opening into a gas outlet opening to run essentially parallel to each other. If the gas outlet openings lie in a plane, the gas passage holes preferably run mathematically in parallel. If the gas outlet openings lie on a cylindrical peripheral surface, the gas passage holes preferably run in a radial direction. Provision can furthermore be made for the gas outlet holes not to be aligned with one or a plurality of gas supply lines. Provision can furthermore be made for the cavities, in particular gas lines, within the quartz component not to run in a straight line, but to have a plurality of changes of direction. The gas supply lines can have sections running in a straight line, which translate into one another in the form of kink points. However, the gas lines can also extend sinuously through the quartz component, and, in particular, can run on a three-dimensionally sinuous path. In particular, provision is made that processes are carried out in the CVD reactor in which the process temperature is greater than 600, 800, 1,000 or 1,200° C., so that the component can be heated up to these temperatures. In particular, the quartz component can be heated to any temperature that is permissible for the use of quartz components.
Example embodiments of the invention are explained below with reference to the accompanying drawings. Here:
The susceptor 19 is supported on a support plate 44, which consists of quartz. The support plate 44 is supported on a support tube 45, which also consists of quartz. A diffusion barrier 46 produced from quartz extends between the heating device 24 and the susceptor 19.
Inside the reactor housing 1 is located a process chamber ceiling 23, through which an attachment section 3 projects into the process chamber 20. The gas inlet unit 2 is fastened to the attachment section 3, which can be made of metal, in particular stainless steel.
The gas distribution bodies/sections 4.1, 4.2, 4.3, 4.4 and 4.5 shown in
A circular gas distribution wall 6 extends from the circular edge of a dividing floor 11, which wall 6 has a multiplicity of uniformly arranged gas passage holes 13. The gas passage holes 13 have a diameter that is smaller than 3 mm, and in particular is smaller than 1 mm. The gas passage holes 13 extending in a radial direction in each case open into a gas outlet opening 7. The height of a gas distribution body 4.1, 4.2, 4.3, 4.4, 4.5 measured in the axial direction of the gas inlet unit 2—with respect to the figure axis—can be between 5 mm and 2 cm. The width of the gas distribution wall 6 extending in the radial direction—with respect to the figure axis—can similarly be in the range between 0.5 cm and 2 cm.
The gas distribution wall 6 surrounds a gas distribution chamber 8, which extends around the central section 15. In an example embodiment, the gas distribution chamber 8 is divided into three annular sections 8′, 8″ and 8′″. A first section 8′ of the gas distribution chamber 8 extends from the gas distribution wall 6 to a flow barrier 12, which is arranged concentrically with respect to the gas distribution wall 6. Radially inside the section 8′ of the gas distribution chamber 8 surrounded by the flow barrier 12, extends a second flow barrier 12′ also running concentrically with respect to the gas distribution wall 6, which flow barrier 12′ surrounds a section 8′″ of the gas distribution chamber 8, which section 8′″ is adjacent to the central section 15. The flow barriers 12, 12′ have the same height as the gas distribution wall 6, and in the example embodiment also have the same radial width. The distance between two adjacent flow barriers 12, 12′, or between the central section 15 and the flow barrier 12′, or between the flow barrier 12 and the gas distribution wall 6, is greater than the wall thickness of the flow barriers 12, 12′, or the wall thickness of the gas distribution wall 6. In particular, the radial width of the sections 8′, 8″, 8′″ of the gas distribution chamber 8 is greater than 1 cm.
The annular flow barriers 12, 12′ have gas passage holes 14, 14′, which are arranged in a uniform peripheral distribution. The diameters of the gas passage holes 14, 14′ can have the same diameters as the gas passage holes 13. However, provision is also made for the gas passage holes 14′ of an inner flow barrier 12′ to have a smaller diameter than the gas passage holes 14 of an outer flow barrier 12, and for the gas passage holes 13 of the gas distribution wall 6 to have a larger diameter than the gas passage holes 14 of the flow barrier 12.
The central section 15 is designed as a plinth, and has the same axial height as the flow barriers 12, 12′, or the gas distribution wall 6, so that the tops of the flow barriers 12, 12′ and the gas distribution wall 6 lie in the same plane in which a wide surface 15′ of the plinth 15 also extends.
Each of the plinths has an outlet 10, with which a gas inlet duct 9.1, 9.2, 9.3, 9.4 and 4.5, associated with the respective gas distribution body 4.1, 4.2, 4.3, 4.4, 4.5, opens into the radially inner section 8″ of the gas distribution chamber 8. The outlets 10 extend from the upper face of the dividing floor 11 to the lower face of the dividing floor 11 of an upper gas distribution body.
It is also considered to be advantageous if the individual gas distribution bodies 4.1, 4.2, 4.3, 4.4 and 4.5 can in each case be machined “from the solid” out of a quartz blank. It is also considered to be advantageous if the entire gas inlet unit 2, with the gas distribution bodies 4.1, 4.2, 4.3, 4.4 and 4.5, which are then connected to each other in a materially integral manner, can be machined out of a single blank.
The SLE method mentioned above is preferably used for the manufacture of the gas inlet unit 2, in which a highly focused and ultra-short pulsed laser beam is used to alter the material of volumetric regions of the quartz blank by a form of writing. These volumetric regions are the gas passage holes 13, the gas passage holes 14, the sections 8′, 8″, 8′″ of the gas distribution chamber 8, the gas inlet ducts 9.1, 9.2, 9.3, 9.4, 9.5, their outlets 10, and the attachment opening 17. After the material transformation has taken place, the transformed material is dissolved out of the quartz body by means of an etching liquid.
It is considered to be particularly advantageous if the parts to be assembled can be minimized with this production method.
The second example embodiment shown in
The gas inlet unit 2 consists of a one-piece quartz component. The cavities are produced using the SLE process.
In the third embodiment illustrated in
The susceptor 19 has a gas supply line 39, with which a purge gas can be fed into a pocket 40. A substrate carrier 33, which floats on a gas cushion, is supported in the pocket 40. The gas generating the gas cushion is fed in through the supply line 39.
The substrate carrier 33 has a supply line 39 on its lower face, which opens into a gas distribution chamber 38, which in turn has openings that open into a pocket 40 of the substrate carrier 33. The substrate 21 is supported in the pocket 40′ of the substrate carrier 33.
In the case of the susceptor 19 and the substrate carrier 33, the distribution chamber 38 and the supply line 39 are produced with the SLE process.
The gas outlet 22 also has cavities. It takes the form of an annular body that surrounds the susceptor 19 and has a plurality of upward facing openings, through which the process gas fed into the process chamber of the CVD reactor can flow into a gas collection chamber, from which the process gas can exit through a gas outlet opening.
A plurality of gas inlet openings arranged on a circular arc line are provided, through which the process gas flows into the annular gas collection chamber. The gas inlet openings have a smaller free cross-sectional area than the gas collection chamber. One or a plurality of gas outlet openings also have in total a smaller free cross-sectional area than the cross-sectional area of the gas collection chamber.
The gas inlet unit 2 can be configured as shown in
The reference numeral 32 designates pyrometers, with which temperatures of the susceptor surface, or the surface of the substrate 21, can be measured. In the process chamber ceiling 23, there is located a light passage plate 34 made of quartz, which has at least one light passage opening 36. In the example of embodiment, three light passage openings 36 are provided, through each of which an optical path passes.
A supply line 39 is provided, through which a purge gas can be fed into the distribution chamber 38.
The example embodiment illustrated in
Adjacent to the gas outlet surface 43 is a coolant volume 41, through which a coolant can flow, in order to cool the gas inlet unit 2. The gas passage holes 13, 13′ pass through the coolant volume 41.
Below the gas outlet surface 43 is arranged a shield plate 42, which also has gas passage holes 13.
Below the shield plate 42 extends a susceptor 19 made of quartz, with pockets, in each of which are inserted substrate carriers 33, which rest on a gas cushion.
As in the previous examples of embodiment, a heating device 24 is provided to bring the susceptor 19 up to a process temperature.
The quartz components described above (gas passage plate 34, substrate support 33, susceptor 19, gas outlet 22, gas inlet unit 2, support plate 44, support tube 45, diffusion barrier 46, sheath 48, and shielding plate 42) can in each case be produced from a quartz blank using the SLE process, wherein it is also envisaged that only individual components of, for example, the gas inlet unit 2 or the susceptor 19 are manufactured using the SLE process, and that the components are bonded to one another with a suitable material bonding agent, for example by means of a borosilicate cement.
The above statements serve to explain the inventions covered by the application as a whole, which inventions in each case also independently further the prior art at least by means of the following combinations of features, wherein two, a plurality, or all, of these combinations of features can also be combined, namely:
A method, which is characterized in that the cavity 8′, 8″, 8″; 13, 14, 14′; 9.1, 9.2, 9.3, 9.4, 9.5; 35, 36, 37, 38, 39, 40, 41 is produced by selective laser etching.
A use of a component produced from a quartz blank, in which at least one cavity 8′, 8″, 8″; 13, 14, 14′; 9.1, 9.2, 9.3, 9.4, 9.5; 35, 36, 37, 38, 39, 40, 41 has been produced by selective laser etching, as a component of a CVD reactor 1, wherein a fluid flows through the at least one cavity 8′, 8″, 8″; 13, 14, 14′; 9.1, 9.2, 9.3, 9.4, 9.5; 35, 36, 37, 38, 39, 40, 41, and the component is heated to temperatures above 500° C. during its use, and comes into contact with hydrides of the IV-, V- or VI-main group, and/or with organometallic compounds or halogen compounds of elements of the II-, III-, or V-main group.
A method or use, which is characterized in that the component is a gas inlet unit 2, a substrate support 33, a gas outlet unit 22, a shield plate 42, a susceptor 19, a light passage plate 34, a support tube 45, a diffusion barrier 46, a support plate 44, a sheath 48, or a cover plate.
A method or use, which is characterized in that the at least one cavity 8′, 8″, 8″; 13, 14, 14′; 9.1, 9.2, 9.3, 9.4, 9.5; 35, 36, 37, 38, 39, 40, 41 has a multiplicity of gas passage openings 13, 14, 14′, which extend between two surfaces of the component, and are arranged in an essentially uniform manner on a gas outlet surface.
A method or use, which is characterized in that the gas passage hole 13, 14, 14′, 37 has a diameter smaller than 3 mm, 2 mm, 1 mm, 0.5 mm, 0.2 mm, or 0.1 mm.
A method or use, which is characterized in that the at least one cavity has a gas distribution chamber 8, 8′, 8″, 38, which communicates with the multiplicity of gas passage holes 13, 14, 14′, 37.
A method or use, which is characterized in that an inner surface of the gas distribution chamber 8, 8′, 8″, 38 is closed in a materially integral manner, except for the gas supply lines 9.1, 9.2, 9.3, 9.4, 9.5, 39 leading into it, and the gas passage holes 13, 14, 14′, 37 leading out of it.
A method or use, which is characterized in that the free cross-sectional area of the gas distribution chamber 8, 8′, 8″, 38 extending transversely to the flow through the component is at least ten times, at least twenty times, at least fifty times, or at least one hundred times, as large as the sum of the free cross-sectional areas of the gas supply lines 9.1, 9.2, 9.3, 9.4, 9.5, 39 leading into the gas distribution chamber or of the gas passage holes 13, 14, 14′, 37 leading out of it.
A method or use, which is characterized in that the gas supply lines 9.1, 9.2, 9.3, 9.4, 9.5, 39 are not in alignment with the gas passage holes 13, 14, 14′, 37.
A method or use, which is characterized in that the at least one cavity is a recess 40, 40′ for the accommodation of a substrate 21, or a substrate holder 33.
A method or use, which is characterized in that the at least one cavity is a gas line 38, 39 which does not run in a straight line, or has one or a plurality of points of changes of direction.
A method or use, which is characterized in that in use the component is exposed to temperatures greater than 600, greater than 800, greater than 1,000, or greater than 1,200° C.
All disclosed features are essential to the invention (individually, but also in combination with each other). The disclosure of the application hereby also includes the full disclosure content of the associated/attached priority documents (copy of the previous application), also for the purpose of including features of these documents in the claims of the present application. The subsidiary claims, even without the features of a claim referred to, characterize with their features independent inventive further developments of the prior art, in particular in order to make divisional applications on the basis of these claims. The invention specified in each claim can additionally have one or a plurality of the features specified in the above description, in particular those provided with reference numerals, and/or in the list of reference numerals. The invention also relates to forms of design, in which individual features cited in the above description are not realized, in particular to the extent that they can recognizably be dispensed with for the respective intended use, or can be replaced by other means having the same technical effect.
Number | Date | Country | Kind |
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10 2018 130 140.5 | Nov 2018 | DE | national |
This application is a National Stage under 35 USC 371 of and claims priority to International Application No. PCT/EP2019/082674, filed 27 Nov. 2019, which claims the priority benefit of DE Application No. 10 2018 130 140.5, filed 28 Nov. 2018.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/082674 | 11/27/2019 | WO | 00 |