Method for producing a component part of a CVD reactor

Abstract

A component made of a quartz blank is used as a component part of a CVD reactor. At least one cavity of the component is created by selective laser etching, wherein a fluid flows through the at least one cavity. When in use, the component is heated to temperatures in excess of 500? C., and comes into contact with hydrides of the main groups IV, V or VI and/or with organometallic compounds or halogenides of elements of the main groups II, III or V.

Claims

1. A method for manufacturing a component of a chemical vapor deposition (CVD) reactor (1), which consists of quartz, and has 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), the method comprising etching 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) by selective laser etching, wherein the component is a gas distribution body (4.1-4.5) of a gas inlet unit (2), wherein the gas distribution body (4.1-4.5) has a central section (15) formed by a plinth, a gas distribution wall (6) and a gas distribution chamber (8), wherein the central section (15) forms an outlet (10) of a gas inlet duct (9.1-9.4) opening into the gas distribution chamber (8) surrounding the central section (15), wherein the gas distribution wall (6) surrounds the gas distribution chamber (8) and has a multiplicity of gas passage holes (13, 14, 14), extending between two surfaces of the gas distribution wall (6), and wherein the gas distribution body (4.1-4.5) is machined out of a single quartz blank.

2. The method of claim 1, wherein the gas distribution body (4.1-4.5) has a circular disc-shaped base plate forming a dividing floor (11) by means of which two gas distribution bodies (4.1-4.5) being arranged one above another are separated from another.

3. The method of claim 2, wherein a top surface of the central section (15) and a top surface of the gas distribution wall (6) extend in a first plane.

4. The method of claim 3, wherein a flow barrier (12, 12) is located between the gas distribution wall (6) and the central section (15), the flow barrier (12, 12) surrounding the central section (15), and wherein a top surface of the flow barrier (12, 12) extends in the first plane.

5. The method of claim 3, wherein an outer surface of the central section (15) forms an inner wall of the gas distribution chamber (8).

6. A gas distribution body (4.1-4.5) of a gas inlet unit (2) machined by etching 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) of the gas distribution body (4.1-4.5), which consists of quartz, by selective laser etching, wherein the gas distribution body (4.1-4.5) has a central section (15) formed by a plinth, a gas distribution wall (6) and a gas distribution chamber (8), wherein the central section (15) forms an outlet (10) of a gas inlet duct (9.1-9.4) opening into the gas distribution chamber (8) surrounding the central section (15), wherein the gas distribution wall (6) surrounds the gas distribution chamber (8) and has a multiplicity of gas passage holes (13, 14, 14), extending between two surfaces of the gas distribution wall (6), and wherein the gas distribution body (4.1-4.5) is machined out of a single quartz blank.

7. The gas distribution body (4.1-4.5) of claim 6, wherein the gas distribution body (4.1-4.5) has a circular disc-shaped base plate forming a dividing floor (11) by means of which two gas distribution bodies (4.1-4.5) being arranged one above another are separated from another.

8. The gas distribution body (4.1-4.5) of claim 7, wherein a top surface of the central section (15) and a top surface of the gas distribution wall (6) extend in a first plane.

9. The gas distribution body (4.1-4.5) of claim 8, wherein a flow barrier (12, 12) is located between the gas distribution wall (6) and the central section (15), the flow barrier (12, 12) surrounding the central section (15), and wherein a top surface of the flow barrier (12, 12) extends in the first plane.

10. The gas distribution body (4.1-4.5) of claim 8, wherein an outer surface of the central section (15) forms an inner wall of the gas distribution chamber (8).

11. A gas inlet unit (2) comprising a plurality of gas distribution bodies (4.1-4.5), each of the gas distribution bodies (4.1-4.5) being an instance of the gas distribution body (4.1-4.5) of claim 10, wherein the plurality of gas distribution bodies (4.1-4.5) are stacked one on top of another.

12. The gas inlet unit (2) of claim 11, wherein the plurality of gas distribution bodies (4.1-4.5) are joined to one another by at least one of material bonding or a screw (30).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Example embodiments of the invention are explained below with reference to the accompanying drawings. Here:

(2) FIG. 1 shows, essentially schematically, in a longitudinal cross-section, the structure of a CVD reactor with a gas inlet unit 2 according to the invention,

(3) FIG. 2 shows five gas distribution bodies 4.1, 4.2, 4.3, 4.4 and 4.5 arranged one above another to form a gas inlet unit 2,

(4) FIG. 3 shows a gas inlet unit in a view,

(5) FIG. 4 shows the gas inlet unit illustrated in FIG. 3 in a section along the line IV-IV in FIG. 3,

(6) FIG. 5 shows in an enlarged manner the detail V in FIG. 4,

(7) FIG. 6 shows a section along the line VI-VI in FIG. 4,

(8) FIG. 7 shows a second example embodiment of a gas inlet unit,

(9) FIG. 8 shows a third example embodiment in an illustration as in FIG. 1 with a gas inlet unit 2 configured according to the invention, a susceptor 19 configured according to the invention, a substrate carrier 33 configured according to the invention, a gas outlet 22 configured according to the invention, and with a light passage plate 34 configured according to the invention,

(10) FIG. 9 shows in an enlarged manner the detail IX in FIG. 8,

(11) FIG. 10 shows in an enlarged manner the detail X in FIG. 8,

(12) FIG. 11 shows the section along the line XI-XI in FIG. 10,

(13) FIG. 12 shows a fourth example embodiment of the invention in an illustration as in FIG. 1, with a gas inlet unit 2 configured according to the invention, a shield plate 42 configured according to the invention, and a susceptor 19 configured according to the invention,

(14) FIG. 13 shows the section along the line XIII-XIII in FIG. 12,

(15) FIG. 14 shows the section along the line XIV-XIV in FIG. 12,

(16) FIG. 15 shows a further example embodiment in the form of a sheath for an optical waveguide and

(17) FIG. 16 shows the section along the line XVI-XVI in FIG. 15.

DETAILED DESCRIPTION

(18) FIG. 1 shows, essentially schematically, the structure of a CVD reactor in whose process chamber 20 a CVD deposition process can be carried out, in which a layer, in particular a semiconducting layer, can be deposited on a plurality of substrates 21. The substrates 21 can consist of III-V compounds, of silicon, of sapphire, or of another suitable material. One or a plurality of layers are deposited on the substrate, which can consist of elements of the IV-main group, the III-V main group, or the II-VI main group. Various process gases are introduced into the process chamber 20 through a gas inlet unit 2 by means of a carrier gas, for example H.sub.2, or a noble gas, wherein the process gases can contain hydrides of the V-main group, the IV-main group, or organometallic compounds of the IV-main group or the III-main group. A susceptor 19 of coated graphite, or similar, carrying the substrates 21 is brought to a process temperature from underneath by a heating device 24, so that the process gases fed by means of the gas inlet unit into the center of the process chamber 20 pyrolytically decompose on the surfaces of the substrates, arranged in a circle around the center, to form a layer, in particular a single-crystal layer. The process gas, which flows through the process chamber 20 in the radial direction, leaves the process chamber 20 through a gas outlet 22 surrounding the susceptor 19, which gas outlet 22 is connected to a vacuum pump (not shown).

(19) 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.

(20) 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.

(21) The gas distribution bodies/sections 4.1, 4.2, 4.3, 4.4 and 4.5 shown in FIG. 2 in each case have a circular disc-shaped base plate, on which a dividing floor 11 is designed, by means of which, gas distribution bodies 4.1, 4.2, 4.3, 4.4 and 4.5 arranged one above another are separated from one another.

(22) 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 2with respect to the figure axiscan be between 5 mm and 2 cm. The width of the gas distribution wall 6 extending in the radial directionwith respect to the figure axiscan similarly be in the range between 0.5 cm and 2 cm.

(23) 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.

(24) 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.

(25) 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.

(26) 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.

(27) 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.

(28) 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.

(29) It is considered to be particularly advantageous if the parts to be assembled can be minimized with this production method.

(30) The second example embodiment shown in FIG. 7 is a gas inlet unit 2 with two gas distribution chambers 8 arranged one above another, wherein the gas distribution chambers 8 are divided by means of a flow barrier 12 into two sections, namely an upstream section 8 and a downstream section 8. A gas duct 9.1, 9.2 opens into each gas distribution chamber 8. The essentially cylindrical body of the gas inlet unit 2 has gas passage holes 13, 14, 14 on its cylindrical peripheral surface, and thereby forms a gas distribution wall 6. The two gas distribution chambers 8 are separated from each other by means of a dividing floor 11. A base plate 31 forms the floor of the lower gas distribution chamber 8.

(31) The gas inlet unit 2 consists of a one-piece quartz component. The cavities are produced using the SLE process.

(32) In the third embodiment illustrated in FIGS. 8 to 11, a susceptor 19, a gas outlet 22, a substrate support 33, a gas inlet unit 2, and a light passage plate 34 are made of quartz. These components are also produced using the SLE process.

(33) 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.

(34) 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.

(35) 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.

(36) 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.

(37) 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.

(38) The gas inlet unit 2 can be configured as shown in FIGS. 1 to 6, or as shown in FIG. 7.

(39) 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.

(40) FIGS. 10 and 11 show the light passage opening 36 in an enlarged manner. The light passage opening 36 is surrounded by a gas distribution chamber 38, from which purging channels 37 extend to the light passage opening 36, so as to purge the light passage opening 36 with a purge gas. The distribution chamber 38 surrounds the light passage opening 36 in a circular annulus. Radially inwardly directed purging channels 37 extend from the distribution chamber 38, wherein the purging channels 37 run obliquely to the direction of the light passage opening 36.

(41) A supply line 39 is provided, through which a purge gas can be fed into the distribution chamber 38.

(42) The example embodiment illustrated in FIGS. 12 to 14 shows a CVD reactor 1 with a showerhead gas inlet unit 2, in which two different process gases can respectively be fed through two gas inlet ducts 9.1, 9.2 into a respective gas distribution chamber 8. The two gas distribution chambers 8 lie vertically one above another, and in each case have gas passage holes 13, 13, which end in a gas outlet surface of the gas inlet unit 2. Within each gas distribution chamber 8 there is located a flow barrier 12, 12 with gas passage holes 14, wherein the flow barriers 12, 12 act as pressure barriers.

(43) 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.

(44) Below the gas outlet surface 43 is arranged a shield plate 42, which also has gas passage holes 13.

(45) 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.

(46) As in the previous example embodiments, a heating device 24 is provided to bring the susceptor 19 up to a process temperature.

(47) FIGS. 15 and 16 show a sheath 48 for an optical waveguide 49. The optical waveguide 49 is inserted in a central cavity 36. Gas passage holes 37 open into the cavity 36, which holes connect to gas supply lines 39 with the formation of an acute angle, which lines run parallel to the inner wall of the cavity 36 in the axial direction of the cavity 36. A plurality of peripherally evenly distributed arrangements of cavities 37, 39 are provided, which form purge lines for purposes of feeding a purge gas into the cavity 36.

(48) 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.

(49) 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:

(50) 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.

(51) 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.

(52) 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.

(53) 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.

(54) 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.

(55) 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.

(56) 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.

(57) 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.

(58) 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.

(59) 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.

(60) 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.

(61) 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.

(62) 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.

LIST OF REFERENCE SIGNS

(63) 1 CVD reactor 2 Gas inlet unit 3 Attachment section 3 Attachment surface 4.1 Gas distribution body/section 4.2 Gas distribution body/section 4.3 Gas distribution body/section 4.4 Gas distribution body/section 4.5 Gas distribution body/section 5 Gas supply line 6 Gas distribution wall 7 Gas outlet opening 7 Gas outlet opening 8 Gas distribution chamber 8 Downstream section 8 Downstream section 8 Upstream section 9.1 Gas inlet duct 9.2 Gas inlet duct 9.3 Gas inlet duct 9.4 Gas inlet duct 9.5 Gas inlet duct 10 Outlet 11 Dividing floor 12 Flow barrier 12 Flow barrier 13 Gas passage hole 13 Gas passage hole 14 Gas passage hole 14 Gas passage hole 15 Central section plinth 15 Wide surface 16 Outlet opening 17 Attachment opening 18 Baffle 19 Susceptor 20 Process chamber 21 Substrate 22 Gas outlet, -unit 23 Process chamber ceiling 24 Heating device 25 Recess 26 Gas outlet opening 27 Attachment opening 28 Nut 29 Spring 30 Fixing screw 31 Base plate 32 Pyrometer 33 Substrate carrier, -holder 34 Light passage plate 35 Cavity, optical path 36 Cavity, light passage opening 36 Cavity, light passage opening 37 Cavity, gas passage hole, purging channel 38 Cavity, gas distribution chamber 39 Cavity, gas supply line 40 Cavity, recess, pocket 40 Recess, pocket 41 Cavity, coolant volume 42 Shield plate 43 Gas outlet surface 44 Support plate 45 Support tube 46 Diffusion barrier 47 Flange section 48 Sheath 49 Optical waveguide