WO2007060143A1

WO2007060143A1 - Cvd reactor with replaceable process chamber cover

Info

Publication number: WO2007060143A1
Application number: PCT/EP2006/068642
Authority: WO
Inventors: Johannes KÄPPELER; Walter Franken
Original assignee: Aixtron Ag
Priority date: 2005-11-25
Filing date: 2006-11-20
Publication date: 2007-05-31
Also published as: TW200728496A; EP1954852A1; DE102005056324A1; TWI402373B

Abstract

The invention relates to a device for depositing at least one layer on at least one substrate (2), comprising a process chamber arranged inside a reactor housing (1). Said process chamber has a process chamber base formed by a substrate support (4), a process chamber cover (5, 6) opposite the base, and a gas inlet element (7) for allowing a process gas containing layer-producing components to enter. The process chamber cover (5, 6) has a cover plate (6) which is arranged below a cover plate support (5) and which extends substantially across the entire horizontal surface of the substrate support (4). The aim of the invention is to improve operation of the aforementioned device. For this purpose, the gas inlet element (7) located in the lateral center of the process chamber (3) is fed through an opening of the substrate support (4) and the cover plate (6) which is detachably associated with the cover support (5) can be replaced through a lateral opening (9) of the reactor housing (1).

Description

CVD reactor with exchangeable process chamber ceiling

The invention relates to a device for depositing at least one layer on at least one substrate with a process chamber arranged in a reactor housing, which has a process chamber bottom formed by a substrate holder, a process chamber ceiling opposite this and a gas inlet element for admitting a process gas containing layer-forming components, the process chamber Process chamber ceiling has a ceiling panel arranged below a ceiling panel support, which essentially extends over the entire horizontal surface extent of the substrate holder.

Such a device is known from DE 102 11 442 A1. This device is used to deposit layers on substrate surfaces, the substrates resting in a process chamber on a substrate holder which is heated from below. The ceiling of the process chamber is formed by the lower wall of a gas inlet element which has a large number of gas outlet openings opening into the process chamber. A diffuser plate, which forms the actual ceiling of the process chamber, extends below the underside of this gas inlet element.

A CVD reactor is also known from DE 103 20 597 A1. Here, too, the substrates rest on a substrate holder which forms the process chamber floor and is heated from below. In contrast to the previously discussed CVD reactor, a process gas component is additionally introduced into the process chamber through a central opening in the substrate holder, ie from below.

DE 4037580 describes a dusting device. A device is provided there for changing a target. The target is directed towards ner area extension shifted into an exchange chamber. In addition, means are provided to displace the target transversely to this direction.

EP 0869199 describes a process chamber that can be closed by a plate valve. If the plate valve is closed, the ceiling of the process chamber can be opened to remove a target located there.

A cluster tool is known from US 5769952, which comprises a plurality of process chambers. One of the process chambers has an opening through which a substrate can be introduced into the process chamber. The substrate is held with a border.

JP 05195218 A describes a sputtering device in which the ceiling is provided with a protective plate.

JP 07228970 A also describes a sputtering device in which a target can be exchanged.

JP 05230625 A describes a device for depositing thin layers in a vacuum chamber. The layer material is removed from a target using a laser beam. The latter can be removed from the vacuum chamber through a vacuum lock.

DE 102004035335 Al describes a clean room-compatible coating system. There, glass-like, glass-ceramic and / or ceramic layers are to be deposited on substrates in a vacuum chamber.

DE 102004045046 A1 describes a method and a device for applying an electrically conductive transparent coating to a substrate. US 6321680 B2 describes a CVD device in which layer deposition is supported by a plasma. The substrates are combined in a magazine, which can be brought into the deposition chamber by a manipulator.

The invention has for its object to improve the device mentioned operationally.

The object is achieved by the invention specified in the claims, each of the claims representing an independent solution to the object and each claim being combinable with any other claim.

According to the invention it is initially and essentially provided that the gas inlet element arranged in the lateral center of the process chamber is fed through an opening in the substrate holder. All process gases can be introduced into the process chamber from below. For this purpose, it is advantageous if the gas inlet element projects through the opening of the substrate holder. In particular, two different process gases are introduced into the process chamber, a first process gas being an organometallic compound and a second process gas being a metal hydride, so that depending on the choice of

Process gases mixed crystals of the third and fifth or the second and sixth main group can be separated. The releasable assignment of the ceiling tile to the ceiling tile support is important. The ceiling panel can be attached to the ceiling panel support with suitable hooks or quick-release fasteners. The reactor housing also has a lateral opening through which the ceiling plate can be replaced. The ceiling tile support can be cooled. While the ceiling tile support consists of a metal, the ceiling tile itself can consist of graphite or preferably quartz or sapphire. The exchange of the ceiling plate is facilitated by the fact that the ceiling plate extends essentially without interruption over the entire cross-sectional extent of the underside of the ceiling plate carrier, so that There is a free space between the ceiling plate and the end face of the gas inlet element. In order to keep the opening for exchanging the ceiling plate as small as possible or to be able to use this opening to load or unload the substrate holder with substrates, it can be provided that the ceiling plate carrier can be displaced vertically. It can be lowered from a process position to a ceiling plate replacement position. In this ceiling panel replacement position, the ceiling panel support is located approximately in the middle of the side opening, i.e. below its upper edge, so that a robot arm can reach into the process chamber in order to grip the ceiling panel and remove it from the process chamber and replace it with a new one. The quick-release fasteners with which the ceiling panel is attached to the ceiling panel support are released. In the process position, which can also correspond to a loading and unloading position, the substrate holder can be accessed in a known manner with a robot arm. The substrates arranged there can be removed and exchanged for substrates to be coated. The substrate holder preferably has an annular shape. Several substrates are arranged in a ring on the periphery around the gas inlet element. The substrate holder is driven in rotation from below, for which purpose the gas inlet element forms a hollow shaft which can be driven in rotation. A plurality of gas supply channels can be arranged in the hollow shaft in order to transport the process gases to the gas outlet openings from which the process gases emerge in the horizontal direction. The gas outlet openings preferably extend one above the other in the circumferential direction. The openings are thus in the area of a cylindrical surface. The substrate holder is heated from below. For this purpose, there is a high-frequency heating spiral inside the reactor housing. In a preferred embodiment, not only the ceiling tile support can be moved vertically together with the ceiling tile, but also the substrate holder arrangement including the gas inlet element. The side opening can be closed gas-tight by means of a gate. The ceiling plate support preferably hangs on the ceiling of the reactor housing. ses. The suspension is able to lower the ceiling tile support. A coolant can flow through the holder.

The invention also relates to a method for depositing at least one layer on at least one substrate in a previously described process chamber. It is essential that after each process step the ceiling tiles, on which an undesired deposition has taken place, are removed from the process chamber. The robot arm that removes the ceiling panel from the process chamber first brings this ceiling panel into a storage cassette in order to store it temporarily. A cleaned ceiling plate is then removed from an etching chamber, which is likewise arranged outside the reactor housing, and introduced into the process chamber. There it is then attached under the ceiling tile support. The etching chamber is a hermetically sealed reaction chamber in which a dry etching process can take place, for example by introducing gaseous HCl. At the corresponding process temperatures, the introduced HCl etches off a parasitic metal coating from the ceiling plate. The ceiling plate cleaned in this way can remain in the etched chamber in the cleaned state until it is needed. If the etching step is shorter than the process step carried out parallel to the etching step in the reactor, the cleaned ceiling plate can be stored there under a protective gas atmosphere. However, it is also possible to first bring the parasitically coated ceiling panel into the etching chamber and then to store the cleaned ceiling panels in a cassette.

The bracket with which the ceiling plate is attached to the ceiling support preferably engages on the edge of the ceiling plate. In this case, the holder can engage under the essentially circular ceiling plate, each with a hook-shaped extension, at several, in particular three, locations arranged in a uniform angular distribution. The brackets can be formed by rods which protrude from above through the process chamber ceiling and extend in the vertical direction. are available. The rods can also be rotated to bring the hook-shaped extensions under the edge of the ceiling plate or to release the ceiling plate for removal.

An embodiment of the invention is explained below with reference to the accompanying drawings. Show it:

1 shows the cross section of a reactor housing with the details necessary for explaining the inventive concept in a process position which also corresponds to a loading and unloading position,

Fig. 2 is an illustration of FIG. 1 in a ceiling panel replacement position and

Fig. 3 is a schematic representation of a device consisting of reactor housing 1, etching chamber 22 and cassette 21.

The reactor housing 1 consists of a metal housing which is gas-tight to the environment. The ceiling of the reactor housing 1 can be removed for maintenance purposes. A ceiling plate support 5 is attached to the ceiling of the reactor housing 1. For this purpose, brackets 18, 19 are used, which at the same time serve as supply or discharge of a coolant in order to cool the ceiling panel support 5. For this purpose, the ceiling panel support 5 has a coolant chamber 16.

The brackets 18, 19 are designed such that the vertical distance of the ceiling plate support 5 from the ceiling of the reactor housing 1 can be varied. The supply line 18 or discharge line 19 for the coolant can be telescopic, for example. The underside of the ceiling panel support 5 forms a substantially circular disk-shaped flat contact surface for a ceiling panel 6. The ceiling tile support 5 is made of a metal, for example aluminum or stainless steel. The ceiling panel 6 has essentially the same contour as the underside of the ceiling panel support 5.

It too has the shape of a circular disk, the ceiling plate 6 of the exemplary embodiment extending uninterruptedly over the entire surface of the underside of the ceiling plate support. There are therefore no openings in the ceiling plate 6. Also, no components of the reactor protrude through the ceiling plate 6. The ceiling plate 6 is, however, attached to the ceiling plate support 5 with detachable brackets. The holding means can be formed by hooks. However, it is also conceivable to connect the ceiling panel 6 to the ceiling panel support 5 by means of a bayonet catch.

The process chamber 3 extends below the ceiling plate 6, so that the ceiling plate 6 forms the ceiling thereof. The process chamber 3 also has a rotationally symmetrical design. In the center of the process chamber 3 there is a gas inlet element 7 with which the process gases can be introduced into the process chamber 3. The essentially cylindrical gas inlet element 7 projects through a central opening 8 of a substrate holder 4 from below. While the cover plate 6 consists of an essentially thermally and electrically insulating material, for example quartz or sapphire, the substrate holder 4 preferably consists of graphite. Basically, the ceiling plate 6 can also consist of graphite. The annular disk-shaped substrate holder 4 has a plurality of pockets arranged in the circumferential direction. These pockets are open at the top and have a pot-shaped shape. In these pockets are circular disc-shaped susceptors 15, which can rotate in the pockets on a gas rotary bearing. A substrate 2 to be coated is located on each of the susceptors 15. A heating spiral 11 is located below the substrate holder 4. This can be a resistance heating. However, it is preferably an RF transmitter coil that induces eddy currents in the electrically conductive substrate holder 4, which lead to the heating of the substrate holder 4.

The gas inlet member 7 is formed by a hollow shaft 12. This hollow shaft 12 can protrude through the bottom of the reactor housing 1. The hollow shaft 12 is preferably driven in rotation. The hollow shaft 12 carries the substrate holder 4, so that the rotational movement of the hollow shaft 12 is transmitted to the substrate holder 4. The gas forming the above-described gas rotary bearing can be fed through the hollow shaft 12. The process gas, which is a hydride of an element of III. or IL main group on the one hand and around an organometallic compound of an element of V. or VI. Main group, on the other hand, can act. Both the hydride and the organometallic compound are introduced into the process chamber together with a carrier gas. Separate flow channels 13, 14 are used for this purpose. The hydride, which can be AsH ₃ , PH ₃ or NH ₃ , is passed through a central flow channel 14 into the area under the end plate 7 ′ of the gas inlet element 7. There the initially vertical flow of the process gas is diverted into a horizontal flow. The process gas flows in the radial direction from outlet openings 14 ', which extends over a circumferential surface zone into the process chamber 3. Below the outlet opening 14' of the flow channel 14, there is an outlet opening 13 'for the metal-organic connection which is in the form of a cylinder jacket. This outlet opening 13 ', from which the organometallic compound flows out together with the carrier gas carrying it in the horizontal direction, forms the end of a flow channel 13, through which the organometallic compound is likewise fed through the underside of the reactor housing 1. The lower gas outlet opening 13 ′ extends directly above the surface of the substrate holder 4 facing the process chamber 3. The outlet opening 14 ′ opens into the process chamber 3 below the axial center of the process chamber 3.

In the exemplary embodiment, it is not only possible to lower the ceiling panel support 5 together with the ceiling panel 6 releasably attached to its underside in the direction of the arrow labeled A in FIG. 1. In the exemplary embodiment, it is also possible to lower the entire substrate holder arrangement consisting of the substrate holder 4 and the gas inlet member 7 carrying it, as well as the heating coil 11 underneath, in the direction of the arrow denoted by B.

In this way, the entire process chamber 3 can be shifted like an elevator.

1 shows a loading and unloading position. In this vertical position of the process chamber and in particular of the substrate holder 4, the surface of the substrate holder 4 facing the process chamber 3 lies in the access area through the lateral opening 9 of the reactor housing 1. The surface of the substrate holder 4 facing the process chamber 3 is here above the height of the lower edge of the Opening 9 and below the upper edge of opening 9. If the gate 17 which closes the opening 9 in a gas-tight manner, a robot arm can reach into the process chamber 3 in order to remove the coated substrates 2 and exchange them for substrates 2 to be coated. The substrate holder 4 is always rotated through a corresponding circumferential angle.

If the entire process chamber arrangement is shifted downward from the position shown in FIG. 1, another robot arm can reach into the process chamber 3 through the lateral opening 9 in order to grip the ceiling plate 6. In this operating position, the upward-facing surface of the substrate holder 4 can lie below the lower edge of the opening 9. However, the ceiling plate 6 lies in an area between the upper edge and the lower edge of the opening 9. As a result, the robot arm only needs to perform a vertical movement. The robot arm releases the ceiling plate 6 from the holder with which the ceiling plate 6 is fastened to the ceiling plate support 5. The robot arm removes the ceiling plate 6 in the direction of the double arrow shown in the area of the lateral opening 9 in FIG. 2 in order to connect a new ceiling plate 6 to the underside of the ceiling plate carrier 5.

The ceiling tile is exchanged between individual coating processes in order to clean the ceiling tile. Since the ceiling panels in the process have a considerably lower temperature than the substrate holder 4, a parasitic coating of the ceiling panel 6 cannot be avoided. Such a parasitic coating of the ceiling plate 6 generally leads to disadvantages because material particles deposited on the surface of the ceiling plate 6 can form and can fall down onto the substrates. By regularly changing the ceiling plate 6, the mass of the material deposited there is kept within tolerable limits.

The ceiling plate support 5 can be rigidly connected to the substrate holder 4 via suitable rigid connections, in particular arranged outside the process chamber 3. With this arrangement, ceiling tile support 5 and substrate holder 4 do not need to be driven separately in the vertical direction. The vertical drive can then engage, for example, in the hollow shaft 12 which is led out of the reactor housing 1 through a bottom opening. The rotary drive can also act on this hollow axis 12 in order to drive the substrate holder 4 around its own axis during the deposition process. However, it is also possible to accommodate the rotary drive and / or the vertical drive within the reactor housing 1.

In the embodiment shown in FIG. 1, the reference numeral 20 designates swivel hooks which can be rotated from the outside. These Swivel hooks reach under the ceiling plate 6 with a hook extension in order to hold it firmly on the ceiling plate holder.

3 shows, roughly schematically, an overall device with a reactor housing 1, an etching chamber 22 and a cassette 21. Between these three chambers 1, 21 and 22 there is a multi-articulated robot arm 23 1 Retract the process chamber 3 shown. The gripper then lies in the free space 10 below the ceiling plate 6. The gripper can then be displaced vertically upwards until it comes into contact with the system on the ceiling plate 6. Then the swivel hook 20 is rotated so that the ceiling plate 6 is free. The ceiling plate is removed from the ceiling plate support 5 by vertically lowering the gripper. The gripper then leaves the process chamber 3 together with the cover plate 6 and places the cover plate in a cassette 21. After the gripping arm 23 has subsequently removed a cleaned ceiling plate 6 from an etching chamber 22, it brings it into the process chamber 3, where it is attached to the ceiling plate support 5 by means of the swivel hook 20.

The swivel hook 20 has a bend at its end which projects into the process chamber 10. This angled portion can engage underneath the ceiling plate 6, which has an essentially circular disk shape. Three or more swivel hooks can be provided, each of which protrude into the interior of the reactor through openings in the reactor housing. The swivel hooks 20 can not only be rotated in order to bring the holding projections into the base position. The swivel hooks 20 can also shift in the vertical direction if it is necessary to lower the ceiling plate 6.

It is considered advantageous that the ceiling plate 6 is only underpinned at its edge by releasable holding means. It is furthermore considered to be advantageous that the ceiling panel is only underpinned in some areas on its peripheral edge. The etching chamber 22 is a reaction vessel hermetically sealed off from the outside world. It can be tempered. It can be brought to a process temperature with suitable heating elements, at which a dry etching process can take place within the etching chamber 22. For this purpose, an etchable gas is introduced into the etching chamber 22. It can be dry HCl. In addition, an inert gas can also be introduced into the etching chamber 22 in order to purge the etching chamber 22. After completion of the etching process, the cleaned ceiling plate 6 can also remain under this protective gas atmosphere within the etching chamber 22 until it is removed there with the reactor arm 23 in order to be inserted into the reactor housing after the gate 17 has been opened in the manner described above.

All of the features disclosed are (in themselves) essential to the invention. The disclosure content of the associated / attached priority documents (copy of the prior application) is hereby also included in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application.

Claims

EXPECTATIONS

1. Device for depositing at least one layer on at least one substrate (2) with a process chamber arranged in a reactor housing (1), which has a process chamber floor formed by a substrate holder (4), a process chamber ceiling (5, 6) opposite this and a gas inlet member ( 7) for the admission of a process gas containing layer-forming components, the process chamber ceiling (5, 6) having a ceiling plate (6) arranged underneath a ceiling panel support (5), which essentially extends over the entire horizontal surface extent of the substrate holder (4), characterized in that the gas inlet element (7) arranged in the lateral center of the process chamber (3) is fed through an opening of the substrate holder (4) and the ceiling plate (6) detachably assigned to the ceiling support (5) through a lateral opening (9) of the reactor housing (1) is interchangeable.

2. Device according to claim 1 or in particular according thereto, characterized in that the ceiling tile support (5) is cooled.

3. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the gas inlet member (7) projects through the opening (8) of the substrate holder (4).

4. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the gas inlet member (7) forms a rotationally driven hollow shaft (12) with which the essentially rotationally symmetrical substrate holder (4) can be driven in rotation.

5. The device according to one or more of the preceding claims or in particular according thereto, characterized by a free space (10) between the upper end face (7 ') of the gas inlet member (7) and the ceiling plate (6).

6. Device according to one or more of the preceding claims or in particular according thereto, characterized in that at least the ceiling tile support (5) can be displaced vertically from a process position into a ceiling tile exchange position.

7. The device according to one or more of the preceding claims or in particular according thereto, characterized in that the lateral reactor housing opening (9) is a loading and unloading opening of the process chamber (3).

8. The device according to one or more of the preceding claims or in particular according thereto, characterized in that the substrate holder (4) can be heated from below, in particular by means of an HF heating coil (11).

9. The device according to one or more of the preceding claims or in particular according thereto, characterized in that both the ceiling (5, 6) and the floor (4) of the process chamber can be displaced vertically.

10. The device according to one or more of the preceding claims or in particular according thereto, characterized in that the process gases are fed from below through a bottom of the reactor housing (1) into the gas inlet member (7).

11. Method for depositing at least one layer on at least one substrate (2) in a process chamber (3) in a reactor housing (1), wherein at least one substrate is held on the substrate holder (4) formed by a process chamber floor and process gas containing layer-forming components is introduced into the process chamber (3) through a gas inlet element (7), an exchangeable ceiling plate (6) below a ceiling plate support (5) is arranged, characterized in that the ceiling plate (6), which is detachably arranged on the ceiling plate carrier (5), is removed after a deposition process by means of a robot arm (23) engaging through a lateral opening (9) of the reactor housing (1), in order to remove it outside the reactor housing (1 ) to be cleaned in an etching chamber (22), the cleaned ceiling plate

(6) is introduced into the process chamber through the lateral opening (9) of the reactor housing (1) and is attached to the ceiling plate support (5).

12. The method according to claim 11 or in particular according thereto, characterized in that a process chamber ceiling (6) is cleaned in an etching chamber (22) arranged outside the reactor housing (1) at the same time as the deposition process.

13. The method according to any one of the preceding claims 11 or 12, characterized in that the ceiling plate (6) is temporarily stored in a storage cassette (21) before or after cleaning in the etching chamber (22).