CN115190918A

CN115190918A - CVD reactor and method for processing a process chamber cover

Info

Publication number: CN115190918A
Application number: CN202180014575.7A
Authority: CN
Inventors: O.费龙
Original assignee: Aixtron Ltd
Current assignee: Aixtron Ltd
Priority date: 2020-02-14
Filing date: 2021-02-12
Publication date: 2022-10-14
Also published as: KR20220141827A; WO2021160785A1; TW202202651A; DE102020103947A1

Abstract

The invention relates to a CVD reactor, comprising a housing (1), a susceptor (5) which delimits the process chamber (23) in the downward direction, and a cover plate (6) which delimits the process chamber (23) in the upward direction, wherein the cover plate (6) can be raised by means of a lifting element (11) which can be raised from a lowered position into a mounting position up to an abutment position which abuts against a fastening section (21) of the housing (1), wherein the cover plate (6) can be fastened to the housing (1) on the fastening section (21). In order to be able to automatically or semi-automatically fix the cover (6) to the housing (1), a lifting element (11) is provided, which lifting element (11) either surrounds the base (5) or supports the base (5) at the edge of the base (5). The lifting element (11) can also be formed by a protective tube. The cover (6) can be brought into a position in which it can be removed through the loading opening (18) by means of the lifting element (11).

Description

CVD reactor and method for processing a process chamber cover

Technical Field

The invention relates to a method for processing a cover plate which delimits a process chamber of a CVD reactor in an upward direction, in particular for the fully or semi-automatic exchange of the cover plate. The invention also relates to an improved design of a CVD reactor in which the cover plate can be raised from a lowered position into a mounted position by means of a lifting element.

Background

A CVD reactor is known from the document DE 102012 110 A1. There, the cover plate is a shielding plate with a gas passage opening arranged below the gas outlet plate of the shower head, which is brought into the installation position by a simultaneous vertical movement of the base and the cover plate, wherein the base is moved in the vertical direction by the lifting device and bears the shielding plate on its surface. There are fixing devices to achieve automatic fixing of the cover plate. A similar device is described in document DE 10 2019 117 479 A1. Document WO 2007/060143 A1 also discloses a cover plate fixed below the gas outlet plate by a retaining element. Furthermore, document JP 5721132 B2 also belongs to the prior art.

Disclosure of Invention

The object of the invention is to improve a device and a method of the type according to the invention in a practical manner.

The above-mentioned object is achieved by the invention specified in the claims, the dependent claims not only being advantageous refinements of the invention in the subclaims but also being independent solutions to the above-mentioned object.

It is first and basically proposed to use as lifting element a body surrounding the susceptor or to use as lifting element a body supporting the susceptor at its edge. The body may be one piece or multiple pieces. The body surrounding the base may be a closed body or a circumferentially interrupted body. The lifting element may be a tube, for example. The body may be formed by a plurality of circumferentially adjacent part-bodies, whereby for example the body may have a planar profile corresponding to a torus. For example, the body may have a circular planar profile. However, the body can also be formed by a plurality of vertically extending rods, columns or the like, which are arranged in different azimuthal positions around the base or the heating device. In a preferred embodiment of the invention, the lifting element can be formed by a support element of the support base, as is known, for example, from DE 10 2007 027 704 A1. The carrier element may have the shape of an upper edge and a tube. The base is supported on the upper edge in the process position. The edge of the base here lies flat on the upper edge. To raise the cover plate using the carrying element, the susceptor is initially taken out of the housing of the CVD reactor through the load port. For this purpose, a door closing the loading opening is opened. It can be provided that for this purpose the ring-shaped venting means surrounding the susceptor must also be lowered so that it does not lie in the movement path of the susceptor, which moves in its plane of extension. The lifting element can be fixed to a vertically movable carrier. The carrier means may be movable in a vertical direction. The carrier device can also carry a heating device with which the susceptor is heated from below in the process position. In a variant of the invention, the air outlet mechanism can perform the function of a lifting element. In a preferred variant, the installation of the cover is automated, in particular fully automated. In particular, provision is made for the cover plate to be replaced semi-automatically or fully automatically. In a variant of the invention, the cover plate can be fixed to a cover of the housing, which closes the upwardly facing housing opening. An air inlet means in the form of a shower head may be secured to the cover. The cover plate may be a protective plate that extends parallel to the air outlet face of the air inlet mechanism. The gas outlet surface may have a plurality of gas outlets opening into the cover plate. There may be a gap between the gas outlet face and the upper surface of the cover plate having the gas passing port, and the gas discharged from the gas outlet face may be distributed in the gap. The edge of the cover plate can form a sealing bead which, in the installed position of the cover plate, bears sealingly against a fastening section, for example a fastening ring or the like. The cover plate can be fixed to the fixing section by fixing means, such as screws, bayonet or the like. One or more fixing means may also be arranged outside the outer ring region of the cover plate. The fastening means can be arranged over the entire surface of the cover plate in order to connect it to the cover or the air inlet. They may also be arranged near the center of the cover plate. The fixing means are preferably designed such that they allow a small lateral movement of the plate relative to the air inlet means without blocking. This makes it possible to compensate for different thermal expansions. In a first variant of the invention, the cover plate used in the preceding deposition process, on which the coating has been formed, is exchanged for a cleaned cover plate when the cover plate is exchanged. For this purpose, the lifting element can be brought into a raised position in which it supports the cover plate fixed to the fastening section. In the position in which the lifting element rests on the cover plate, the fastening means for fastening the cover plate to the fastening portion are released. By lowering the lifting element, the cover plate is brought into a position in which it can be clamped by means of a gripper which projects through the load opening into the interior of the housing, in order to be able to be removed from the interior from the load opening. The cleaned cover plates are fixed on the fixing section in the reverse order. In a second variant of the invention, a lid closing the opening of the housing is raised, said lid carrying the cover plate. Temporary securing means are used in the raised position to hold the cover plate on the securing section. The screws or other fastening means for fastening the cover plate to the fastening section can be released manually or automatically. The lid is then lowered into a position in which the cover plate is carried by the lifting element. In this position, the temporary securing means are released. By lowering the lifting element, the cover plate is released from the fastening section and brought into a position in which it can be gripped by the gripper. The cleaned cover plate is placed on the lifting element. The lifting element is brought into a raised position in which the cover rests against the fastening section, the cover being fastened here with temporary fastening means. The lid may be raised further up to a position in which screws or other fixing means may be mounted. The temporary securing means are removed. Bringing the lid into its closed position. As a temporary fastening means, a C-shaped clip can be used, by means of which the cover is temporarily held on the fastening section, in particular on the cover. The transport of the cover plate from the interior space or into the interior space of the chamber can be effected by a robot arm which can be introduced through the loading opening. In the case of a fully automatic installation, the cover plate is connected to the fastening section by means of a fastening means that can be actuated automatically. In the case of semi-automatic installation, temporary fastening means are used, for example C-shaped clips, by means of which the cover plate is temporarily fastened to the fastening section. This is preferably achieved when the cover is brought into the first open position, in which the cover plate is brought over the upper edge of the housing opening by the lifting element, so that the edge of the cover plate is accessible, onto which temporary fixing means can be fixed. Then, in the case of a semi-automatic installation, the cover is raised further until the downwardly facing broad side of the cover plate is accessible for installing a fixing means there, which may be a screw element, for example. In the case of fully automated installation, this intermediate step is not required. The mounting of the cover plate can be effected when the cover is closed. After the fixing means is fixed, the lifting element can be lowered. If a carrier element is used as the lifting element, which carries the susceptor in the process position, the susceptor must be removed before the cover plate can be exchanged out of the process chamber. This is achieved after lowering the degassing mechanism, which in the process position is located in the movement path of the substrate to be removed. After the cover plate is replaced, the susceptor loaded with the substrate to be coated can be brought into the process chamber through the load port by means of a lowered venting mechanism. This is achieved by a robot arm which places the susceptor on the carrying element. The venting mechanism is then raised until the upper edge of the venting mechanism abuts the edge of the cover plate or the section of the housing surrounding the cover plate. The cover plate can be made of quartz, steel, in particular refined steel, or a ceramic material, which has a passage opening for the passage of a process gas, which is fed into the gap between the cover plate and the gas inlet means. The lifting element surrounding the susceptor may be made of steel, in particular refined steel, quartz or a ceramic material. It may be formed by a tubular body in the cavity of which heating means for heating the susceptor are arranged. The heating device may be vertically movable together with the elevating member. The lifting element can also function as a spacer in the processing position, by which the space arranged below the susceptor is shielded from the process gas. The lifting element can thus form the function of a shielding tube.

The invention also relates to an improved design of the cover plate. The cover plate has an annular ridge near its edge directed towards the inlet means or the outlet plate. The annular ridge defines a gap between the gas plate and the cover plate. The annular bead preferably bears in a sealing manner against the flat underside of the air inlet means or of the air outlet plate formed by the air inlet means. The outlet plate can have a chamfered edge surface in the region of the elevations. The ridge extends in the region of the edge face of the chamfer. The bulge prevents the process gas fed into the gap from being discharged from the side.

Another aspect of the invention relates to an improved design of the cover of the housing. The air inlet mechanism is an integral component of the housing cover. For this purpose, the housing cover forms an annular strip of material which is formed in a uniform manner on the cover plate of the cover. The annular strip has a radially outwardly facing wall which, in the mounted state of the lid, bears against an inner surface of the housing wall. The annular strip also has a radially inwardly directed face against which an outer edge section of the air inlet means bears. The air inlet means is preferably surrounded by and enclosed by an annular strip.

Drawings

Embodiments of the invention are further elucidated with reference to the drawing. In the drawings:

fig. 1 shows a cross section of a CVD reactor in a process position in which a process chamber 23 is delimited downwards by a susceptor 5 and upwards by a cover plate 6, wherein the process chamber 23 is surrounded by a gassing mechanism 3,

figure 1a shows an enlarged view of part Ia,

fig. 2 shows the view according to fig. 1, however with the air outlet means 3 lowered,

fig. 3 shows the view according to fig. 2, wherein the susceptor 5 is removed through the load port 18,

fig. 4 shows the view according to fig. 3, wherein the cover 2 is brought into a first open position, in which it is located approximately 20 to 30mm above the edge 24' of the opening 24 of the housing 1, wherein the temporary fixing means 19 are arranged to temporarily fix the cover plate 6 on the cover 2,

fig. 5 shows the view according to fig. 4, wherein the lid 2 is brought into the second open position,

fig. 6 shows the view according to fig. 5, in which the screw element 20 for fixing the cover plate 6 to the lid 2 is released and the cover plate 6 is held on the lid 2 only by the temporary fixing means 19,

fig. 7 shows the view according to fig. 6, in which the cover plate 6 held on the lid 2 only by the temporary fixing means 19 is brought into a first open position, in which the upper edge of the lifting element 11 supports the cover plate 6,

fig. 8 shows the view according to fig. 7, in which the temporary fixing means 19 have been removed, so that the cover plate 6 is carried only by the lifting element 11,

fig. 9 shows the view according to fig. 8, after the lifting element 11 has been lowered to a position, in which the cover plate 6 has been released from the lid 2 and can be removed from the load opening 18 by means of the gripper arm,

fig. 10 shows the view according to fig. 9, in which the interior space 22 contains neither the base nor the cover 6, and only then the cleaned cover is brought into the interior space 22, which cover is fastened to the lid 2 substantially in the reverse order,

fig. 11 shows a view according to fig. 1a of a second embodiment, in which the degassing mechanism 3 performs the function of a lifting element.

Detailed Description

Fig. 1 shows the essential components of a CVD reactor in cross section cut through it. The CVD reactor has a gas-tight housing 1 with an opening 24 facing upwards. In the process position shown in fig. 1, the opening 24 is closed by the cover 2. The cover 2 is provided with an air inlet means 4 in the form of a shower head. The gas inlet means 4 has a gas distribution volume which is delimited downwards by a gas outlet plate 21 which forms a gas outlet face by its bottom face. The gas outlet plate 21 has a plurality of gas outlets 17 through which gas can be discharged from the gas distribution chamber 17 into the gap 15. The gap 15 extends between the outlet plate 21 and the cover plate 6 arranged below the inlet means 4. The edge of the substantially disk-shaped cover plate 6 has a bulge 14, which bulge 14 rests on an edge section of the gas outlet plate 21, wherein the height of the bulge 14 defines the height of the gap 15. However, other distance elements, not shown in the figures and arranged in the area enclosed by the bulge 14, may also be provided to define the gap. Thermal deformations can be compensated for by such spacer elements. The height of the gap 15 can additionally also be defined by other distance elements. The cover plate 6 has a plurality of gas passage openings 16 through which the gas entering the gap 15 can flow into a process chamber 23 arranged below the cover plate 6. The cover 6 delimits the process chamber 23 upwards, while the base 5 delimits the process chamber 23 downwards.

The edge of the cover plate 6 can have a lower material thickness in the region in which the circumferential bead 14 is arranged than in the central region, wherein the material thickness preferably decreases on the upper side in order to be able to form a gap which rises outward relative to the intake device. The material thickness can also decrease on the upper side in order to form a gap that rises outward relative to the air intake.

The edges of the base 5 are supported on a carrier element, which in an embodiment may have the shape of a tube. It can be formed in particular by a protective tube 11. The protective tube 11 encloses a device with the heating device 7, which is located below the base 5 and has a carrier plate 12 for supplying the heating device 7 with current. The support element, i.e. in particular the protective tube 11 and the heating device 7, can be raised by means of the lifting device 10. In a variant of the invention, the tube 11 has the function of carrying the tube, the edge of the base being supported on the tube 11. The tube 11 forms a carrier for the base 5.

The process chamber is surrounded by an annular degassing device 3. By means of a further lifting device, the air outlet mechanism 3 can be lowered from the process position shown in fig. 1, in which it is arranged in front of the load opening 18, to a position in which the load opening 18 is exposed. In the position shown in fig. 2, the susceptor 5 can be gripped by a gripper which projects through the load opening 18 into the interior space 22 of the housing, so that it can be removed from the housing 1 through the load opening 18, as shown in fig. 3, in order to replace another susceptor 5. The element denoted by reference numeral 9 forms an outlet duct through which the gas collected in the outlet means 3 can be conveyed to the outside. However, the element denoted by reference numeral 9 in the figure may also represent a further lifting device by means of which the air outlet means 3 can be lowered and raised.

When the cover plate 6 is replaced in a fully automatic manner, the lifting element 11, which in the exemplary embodiment is formed by a protective tube and engages under the edge region of the cover plate 6, is moved upwards in order to support the cover plate 6 in this way, so that the fastening means holding it on the lid 2 or the air inlet mechanism 4 can be released automatically, as is suggested, for example, in the prior art mentioned at the outset. The cover plate 6 is then brought into the removal position by lowering the lifting element 11, in which it can be removed from the interior 22 by means of the gripper arms which project into the interior 22 through the loading opening 18. The fastening of the replacement cover 6 to the cover 2 or the intake mechanism 4 is effected in the reverse order. The cover plate 6 is placed on the lifting element 11. The lifting element 11 is raised until the cover 6 or the bulge 14 comes to bear against the air inlet 4 or the cover 2. The fixation device is then brought into a fixed position. Additional centering means can be provided, by means of which the cover plate 6 can be brought into a centered position. However, the centering means may also be formed by fixing means.

In order to replace the cover 6 semi-automatically, the lid 2 is raised into a first open position shown in fig. 4, in which the cover is arranged about 10 to 30mm above the opening edge 24', in particular together with the lifting element 11. In the first open position, the C-shaped clip 19 is placed on the cover 6, and the cover 6 is fixed to the fixing section 21 of the cover 2 with screws 20 (see fig. 6). The lid 2 is then brought into the second open position shown in figure 5. Alternatively, the cover 2 can be brought directly into the open position shown in fig. 5, in order to fix a temporary fixing means formed by the C-shaped clip 19 there.

Fig. 6 shows how the above-mentioned screws 20 are released in the second, open position, the cover plate 6 being permanently fixed to the lid 2 by means of the screws 20. The lid 2 is lowered into the first open position with the cover plate 6 held only by the clips 19. In the present exemplary embodiment, the protective tube 11 with the function of a lifting element has been brought into a raised installation position in which the upper edge of the lifting element 11 supports the cover plate 6. The clips 19 are removed so as to achieve the operating position shown in fig. 8, in which the cover plate 6 is carried exclusively by the lifting element 11. The cover 2 may be held in this position by further holding means not shown.

The operating position shown in fig. 9, in which the cover plate 6 lies in the plane of the load opening 18, is achieved by lowering the lifting element 11, so that the cover plate 6 can be removed from the interior 22 by a movement in its plane of extension through the load opening 18 by means of a clamping arm, not shown.

The cleaned cover plate 6 has been secured to the lid 2 in essentially the reverse order. For this purpose, the cover 6 is introduced into the interior 22 of the housing 1, which essentially has the operating position according to fig. 10. The cover plate 6 is placed onto the lifting element 11 according to fig. 9. The lifting element 11 is raised into a first open position shown in fig. 11, in which the cover 6 rests against the air inlet 4 or the cover 2. A temporary fixing means 19 shown in figure 7 is provided which holds the cover plate 6 on the lid 2. Where possible required centering can take place. The lid 2 is raised into a second open position shown in fig. 6, in which second open position screws 20 or other fixing means are mounted, by means of which screws 20 or other fixing means the cover plate 6 is permanently fixed to the lid 2. Alternatively, the centering of the cover plate 6 can also be accomplished by permanent or permanent fastening means 20.

The clip 19 can be removed. It is also possible, however, to lower the cover 2 beforehand into the position shown in fig. 4, in order to remove the clip 19 in this position. The lid 2 is then lowered into the closed position shown in figure 3. The lifting element 11 is brought into the lowered position. In this position, a new susceptor 5 can be brought into the interior space 22 via the loading opening 18, where it rests on the lifting element 11.

Fig. 11 shows a variant of the invention in the view according to fig. 1a, in which the edge of the cover plate 6 can be carried by the upper section of the annular degassing device 3. In this modification, the air outlet mechanism 3 can be lowered not only from the lowered position shown in fig. 2. The air outlet 3 can also be moved from the process position shown in fig. 1 into a not shown raised position in which it projects beyond the edge 24' in order to thus bring the cover plate 6 into the raised position.

Fig. 1 and 1a show an annular strip 25 formed by the underside of the lid, which annular strip 25 is formed in a material-conforming manner on a cover plate made of metal. The annular strip 25 has a radially outwardly facing surface which bears against a surface of the wall of the housing 1. When the lid is closed, the annular strip 25 projects into the opening 24.

The annular strip 25 surrounds the air inlet means 4. The annular strip 25 forms a circular receiving space in which the inlet means 4, which is fixed in contact on the underside of the cover 2, is inserted. The outer edge section 26 of the air inlet means 4 is preferably integrally formed from the material of the air outlet plate 21, the outer edge section 26 having a radially outwardly facing wall which rests against a radially inwardly facing wall of the annular strip 25. The height of the annular strip 25 preferably corresponds to the height of the inlet means 4, so that the surface of the inlet means 4 facing the process chamber 23 extends flush with the axially directed surface of the annular strip 25.

Fig. 1a shows that the surface of the cover plate 6 facing the air inlet 4 extends obliquely in the edge region, so that the material thickness of the cover plate 6 tapers off at the edge. The already mentioned bulge 14 extends into this region and contacts against the intake member 4 or the outlet plate 21. In the exemplary embodiment, the circularly extending bulge 14 bears against the outer edge section 26. The process gas entering the gap 15 through the gas outlet 17 is prevented by the bulge 14 from being discharged laterally from the gap 15.

The above-described embodiments serve to illustrate the invention covered by the present application in general, which respectively also individually improves on the prior art at least by the following combinations of features, wherein two, more or all of these combinations of features can also be combined, namely:

a CVD reactor, characterized in that the lifting elements 11 are formed by one or more bodies surrounding the susceptor 5 or supporting it at its edge.

A method is characterized in that the lifting element 11 is formed by one or more bodies that surround the susceptor 5 or support it at the edge of the susceptor.

A CVD reactor or method, characterized in that the lifting element 11 is a carrying element carrying the susceptor 5 or a gassing mechanism 3 surrounding the susceptor 5.

A CVD reactor or method, characterized in that the lifting element 11 has a circular ring-shaped plan profile and/or the lifting element 11 has the shape of a tube.

A CVD reactor or method, characterized in that the fixed section 21 is formed by a lid 2 closing an opening 24 in the upper part of the housing 1 and the lifting element 11 is raisable to a position where at least one upper section of the lifting element 11 protrudes outwardly beyond the edge 24' of the opening 24.

A CVD reactor or method, characterized in that a cover plate 6 can be fastened or fixed to a fastening section 21 by means of temporary and/or permanent fastening means 19, 20, and/or that the cover plate 6 has an annular bead 14 directed toward the gas inlet 4 or the gas outlet 21, which bead bears in a sealing manner against the gas inlet 4 or the gas outlet 21, and/or that the cover 2 has an annular strip 25 which projects into an opening 24 and surrounds the gas inlet 4.

A CVD reactor or method, characterized in that the fastening section 21 is a gas inlet means 4 or surrounds the gas inlet means 4, wherein the gas inlet means 4 has a plurality of gas outlets 17 opening into a gap 15 between a cover plate 6 and a gas outlet face of the gas inlet means 4, wherein the cover plate 6 has a gas passage opening 16.

A CVD reactor or method, characterized in that the gassing mechanism 3 can be moved from a process position located in the motion trajectory of the susceptor 5 or cover plate 6 into a lowered position.

A CVD reactor or method, characterized in that a fixing section 21 is assigned to a lid 2 closing an opening 24 of a housing 1, and in that, for mounting the lid 6, the lid 2 is brought into a first open position before lifting the lid 6 or while lifting the lid 6, and after said lifting, the lid 6 carried by a lifting element 11 is fixed on the lid 2 by means of a first fixing means 19 and then, after lifting the lid 2, is brought into a second open position, during which the lid 6 is separated from the lifting element 11, fixed on the lid 2 by means of a second fixing means 20, and/or, for taking out the lid 6, the lid 2 is first brought into a first open position, in which the first fixing means 19 is fixed on the lid 2, and after lifting the lid 2 into the second open position, the second fixing means 120 is released and then the lid 2 is brought back into the first open position, in which the lid 6 bears on the lifting element 11, wherein the first fixing means 19 is removed.

All of the disclosed features are inventive in their own right or in combination with each other. The disclosure of the present application therefore also contains the entire disclosure of the attached/attached priority documents (copy of the prior application) with the aim of also incorporating the features of these documents into the claims of the present application. The dependent claims, even without the features of the cited claims, characterize their features independently inventive refinements of the prior art, in particular for divisional applications based on these claims. The invention given in all claims may additionally have one or more of the features given in the above description, in particular with reference numerals and/or in the list of reference numerals. The invention also relates to the embodiments in which individual ones of the features mentioned in the above description are not implemented, in particular as long as they are clearly not necessary for a corresponding purpose of use or can be replaced by other technically equivalent elements.

List of reference numerals

1. Shell body

2. Cover for portable electronic device

3. Air outlet mechanism

4. Air inlet mechanism

5. Base seat

6. Cover plate

7. Heating device

8. Rod

9. Lifting device and air outlet pipe

10. Lifting device

11. Lifting element and protection tube

12. Bearing plate

13. Carrier

14. Raised part

15. Gap

16. Gas passing port

17. Gas outlet and gas distribution chamber

18. Loading port

19. Holding clamp and fixing device

20. Screw, fixing device, threaded element

21. Gas outlet plate and fixing section

22. Inner space

23. Process chamber

24. Opening of the container

Edge of 24' opening

25. Annular strip

26. Outer edge section

Claims

1. A CVD reactor with a housing (1), with a susceptor (5) which delimits a process chamber (23) downwards and with a cover plate (6) which delimits a process chamber (23) upwards, wherein the cover plate (6) can be raised by means of a lifting element (11) which can be raised from a lowered position into a mounted position up to an abutment position against a fixing section (21), on which fixing section (21) the cover plate (6) can be fixed on the housing (1), characterized in that the lifting element (11) is formed by one or more bodies which surround the susceptor (5) or support it at the susceptor edge.

2. A method for processing a cover plate (6) defining a process chamber (23) of a CVD-reactor, arranged above a susceptor (5), having the following steps:

1. -placing the cover plate (6) on a lifting element (11) arranged inside the housing (1);

2. raising a lifting element (11) carrying the cover plate (6) to an installation position;

3. -fixing the cover plate (6) on a fixing section (21) of the housing (1);

4. lowering the lifting element (11) to a lowered position; and/or

5. Raising the lifting element (11) from a lowered position to an installation position;

6. releasing the cover plate (6) from the fastening section (21) of the housing (1);

7. lowering a lifting element (11) carrying the cover plate (6) to the lowered position;

8. -removing the cover plate (6) from the lifting element (11), characterized in that the lifting element (11) is formed by one or more bodies surrounding the base (5) or supporting the base at its edge.

3. A CVD reactor or method according to any of the preceding claims,

the lifting element (11) is a bearing element bearing the base (5) or a gas outlet mechanism (3) surrounding the base (5).

4. A CVD reactor or method according to any of the preceding claims,

the lifting element (11) has a circular ring-shaped planar contour and/or the lifting element (11) has the shape of a tube.

5. A CVD reactor or method according to any of the preceding claims,

the fixing section (21) is formed by a cover (2) closing an upper opening (24) of the housing (1) and the lifting element (11) can be raised to a position in which at least one upper section of the lifting element (11) projects outwards beyond an edge (24') of the opening (24).

6. CVD reactor or method, in particular according to one of the preceding claims, characterized in that the cover plate (6) can be fastened or fastened to the fastening section (21) by means of temporary and/or permanent fastening means (19, 20) and/or in that the cover plate (6) has an annular bead (14) pointing towards the gas inlet means (4) or the gas outlet plate (21), which bead bears in a sealing manner against the gas inlet means (4) or the gas outlet plate (21), and/or in that the cover (2) has an annular strip (25) which projects into the opening (24) and which surrounds the gas inlet means (4).

7. A CVD reactor or method according to any of the preceding claims,

the fastening section (21) is a gas inlet means (4) or surrounds the gas inlet means (4), wherein the gas inlet means (4) has a plurality of gas outlets (17) which open into a gap (15) between the cover plate (6) and a gas outlet face of the gas inlet means (4), wherein the cover plate (6) has a gas passage opening (16).

8. A CVD reactor with a housing (1), with a susceptor (5) which delimits a process chamber (23) downwards, with a cover plate (6) which delimits the process chamber (23) upwards and with a gas outlet means (4) which surrounds the susceptor (5), wherein the housing (1) has a loading opening (18) through which the susceptor (5) or the cover plate (6) can be brought into an interior space (22) of the housing (1) by means of a movement which takes place in the direction of its surface extension, characterized in that the gas outlet means (3) can be moved from a process position which lies in the movement trajectory of the susceptor (5) or the cover plate (6) into a lowered position.

9. Method according to one of claims 2 to 7, characterized in that the fixing section (21) is assigned to a lid (2) which closes an opening (24) of the housing (1), and in that, for mounting the lid (6), the lid (2) is brought into a first open position before the lid (6) is raised or while the lid (6) is raised, and after the raising, the lid (6) carried by the lifting element (11) is fixed on the lid (2) by means of a first fixing means (19) and then is brought into a second open position after the lid (2) is raised, during which the lid (6) is separated from the lifting element (11) and fixed on the lid (2) by means of a second fixing means (20).

10. Method according to one of the preceding claims,

in order to remove the cover (6), the lid (2) is first brought into a first open position, in which the first fastening means (19) is fastened to the lid (2), and the second fastening means (20) is released after the lid (2) has been raised into a second open position, and then the lid (2) is brought back into the first open position, in which the cover (6) rests on the lifting element (11), wherein in this position the first fastening means (19) is removed.

11. A CVD reactor or method, characterized by the features of one or more of the characterizing parts of one of the preceding claims.