Coating device having coated transmitter coil

Abstract

A device, for depositing a layer on a substrate by supplying one or more process gases to a process chamber, includes a susceptor and one or more transmitter coils. The susceptor bearing the substrate can be heated to a process temperature by means of an electromagnetic alternating field generated by the one or more transmitter coils. The one or more transmitter coils have a coating that consists of tin and nickel in order to provide a corrosion-resistant coating, which simultaneously has low emissivity and is therefore effective in the presence of chlorine compounds and moisture.

Claims

1. A device for depositing a layer onto a substrate (4), the device comprising: a process chamber (1), wherein one or more process gases are supplied into the process chamber (1); susceptor (3) for bearing the substrate (4); and one or more transmitter coils (5), wherein the susceptor (3) is heated to a process temperature by means of an electromagnetic alternating field generated by the one or more transmitter coils (5), wherein a coating (9) that includes tin and nickel is present on the one or more transmitter coils (5), wherein each of the one or more transmitter coils (5) comprises a cavity (8) configured to carry a coolant within the one or more transmitter coils (5), and wherein the one or more transmitter coils have an outwardly facing surface formed by the coating (9) that comes into contact with the one or more process gases supplied into the process chamber (1).

2. The device of claim 1, wherein the coating (9) is a mixture of Ni.sub.3 Sn.sub.2 and Ni.sub.3 Sn.sub.4.

3. The device of claim 1, wherein the coating (9) has a nickel content of between 40 and 30% by weight, and a tin content of between 60 and 70% by weight.

4. The device of claim 1, wherein an outermost layer of the coating (9) consists exclusively of nickel and tin.

5. The device of claim 1, wherein a tin/nickel ratio of the coating (9) is 65/35% by weight.

6. The device of claim 1, wherein a thickness of the coating (9) is between 1 and 50 m.

7. The device of claim 1, wherein the coating (9) is galvanically deposited onto the one or more transmitter coils (5).

8. The device of claim 1, wherein the one or more transmitter coils (5) contains copper, the device further comprising a base layer that is applied onto the one or more transmitter coils (5), wherein the base layer contains essentially nickel and bears the coating (9) that includes tin and nickel.

9. The device of claim 8, wherein the base layer has a thickness of 1 to 50 m or at least 30 m.

10. A method, comprising: heating a susceptor (3) that bears a substrate (4), the susceptor heated by an electromagnetic alternating field generated by a spiral-shaped transmitter coil (5), wherein the spiral-shaped transmitter coil (5) has a cavity (8) extending between two ends (6, 7) of the spiral-shaped transmitter coil (5), and wherein the spiral-shaped transmitter coil (5) has an outer wall surrounding the cavity (8), the outer wall coated with a coating (9) that includes nickel and tin; flowing a coolant through the cavity (8) of the spiral-shaped transmitter coil (5); and depositing a layer onto the substrate (4) by supplying one or more process gases into a process chamber (1) that contains the susceptor (3) and the substrate (4), wherein the spiral-shaped transmitter coil (5) has an outwardly facing surface formed by the coating (9) that comes into contact with the one or more process gases supplied into the process chamber (1).

11. The method of claim 10, wherein the coating (9) consists of a mixture of Ni.sub.3 Sn.sub.2 and Ni.sub.3 Sn.sub.4.

12. The method of claim 10, wherein a tin/nickel ratio of the coating (9) lies a range of between 60/40% by weight and 70/30% by weight, and/or a thickness of the coating (9) lies in a range between 1 and 50 m.

13. The device of claim 1, wherein the one or more transmitter coils (5) and the susceptor (3) are contained within the process chamber (1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In what follows the invention is explained with the aid of accompanying figures. Here:

(2) FIG. 1 shows schematically the cross-section of a coating device,

(3) FIG. 2 shows the plan view onto a transmitter coil 5, and

(4) FIG. 3 shows the cross-section of a transmitter coil 5 along line III-III of FIG. 2.

DETAILED DESCRIPTION

(5) A gas-tight housing surrounds a process chamber 1, into which a gas inlet device 2 opens, through which (besides other precursors) chlorine-containing gases, for example chlorine-containing compounds of elements of the III-main group, are also supplied. However, other chlorine-containing compounds can also be supplied through the gas inlet device 2, for example so as to clean the process chamber 1 after a coating process by means of an etching step. Here Cl.sub.2 or HCl in particular can be considered as the gases.

(6) In the process chamber 1 there is a susceptor 3, which consists of graphite or another electrically conductive material, and which bears one or a plurality of substrates 4, which are to be coated. In particular, they can be coated with a semiconductor layer, and in particular with a III-V semiconductor layer.

(7) Underneath and in the same process chamber 1 a transmitter coil 5 is located, which is made of metal and has a spiral shape. The transmitter coil 5 has two ends 6, 7, which are connected in an electrically conductive manner to supply lines arranged outside the process chamber 1 (see WO 01/78105). A coolant can also be supplied through these supply lines, which flows through a cavity 8 of the transmitter coil 5, which cavity has a rectangular or a round cross-section.

(8) The transmitter coil 5, which is made of metal, in particular a Cu-alloy, has an outwardly facing surface that can come into contact with the process gas supplied to the process chamber 1, and in particular with chlorine-containing gases. To prevent chlorine ions from corrosively attacking the metal of the transmitter coil body, the transmitter coil 5 has a coating on its outer surface. The coating 9, which in the prior art consists of a precious metal and in particular gold, in accordance with the invention is formed by a tin-nickel alloy, wherein the tin/nickel ratio is 65/35% by weight, and the layer thickness is 20 m. The coating is applied galvanically.

(9) Before the coating of the transmitter coil 5, it can be pre-treated in a suitable manner; for example, it can be mechanically cleaned by blasting with glass beads. Chemical pre-treatment can take place, for example by depositing a base layer (NiP, NiCo, bronze). The base layer can be 50 m thick. The tin-nickel coating can consist of two phases: Ni.sub.3Sn.sub.2 and Ni.sub.3Sn.sub.4. It therefore takes the form of a metastable phase mixture of two phases.

(10) The coating of the transmitter coil 5 is preferably a multi-layer coating. The transmitter coil 5 preferably consists of copper, or essentially of copper. A layer containing essentially nickel is firstly deposited on the surface of the copper base body. This base layer is preferably a chemical nickel layer. The base layer serves as an additional diffusion barrier and preferably has a layer thickness of at least 30 m. The layer thickness can lie in the range between 30 m and 50 m. On this base layer is deposited the layer consisting of tin and nickel, the thickness of which can lie between 1 and 50 m. It preferably lies in the range between 10 and 20 m. The tin/nickel ratio lies within the range specified above.

(11) The above statements serve to explain the inventions recorded by the application as a whole, which develop the prior art at least by means of the following combinations of features, and in each case also independently, wherein two, a plurality, or all, of these combinations of features can also be combined, namely:

(12) A device, which is characterized in that the coating 9 consists of tin and nickel.

(13) A device, which is characterized in that the coating 9 is a mixture of Ni.sub.3 Sn.sub.2 and Ni.sub.3 Sn.sub.4.

(14) A device, which is characterized in that the coating 9 has a nickel content of between 40 and 30% by weight and a tin content of between 60 and 70% by weight.

(15) A device, which is characterized in that an outermost layer of the coating 9 consists exclusively of the elements nickel and tin.

(16) A device, which is characterized in that the tin/nickel ratio of the coating 9 is 65/35% by weight.

(17) A device, which is characterized in that the thickness of the coating 9 is between 1 and 50 m, or between 1 and 30 m, and is preferably 20 m.

(18) A device, which is characterized in that the coating 9 is galvanically deposited onto the transmitter coil 5.

(19) A device, which is characterized in that a base layer, which essentially contains nickel and bears the coating 9, is applied onto the transmitter coil, which essentially contains copper.

(20) A device, which is characterized in that the base layer has a thickness of 1 to 50 m, and in particular of at least 30 m.

(21) A transmitter coil, which is characterized in that the coating consists of tin and nickel.

(22) A transmitter coil, which is characterized in that the coating 9 is a mixture of Ni.sub.3 Sn.sub.2 and Ni.sub.3 Sn.sub.4.

(23) A transmitter coil, which is characterized in that the tin/nickel ratio lies in the range between 60/40% by weight and 70/30% by weight, and in particular is 65/35% by weight, and/or in that the layer thickness is in the range between 1 and 50 m, and in particular is 20 m.

(24) All disclosed features are essential to the invention (both individually, and also in combination with one another). In the disclosure of the application, the disclosure content of the associated/attached convention documents (transcript of the prior application) is hereby also incorporated in full, also for the purpose of incorporating features of these documents in the claims of the present application. The subsidiary claims characterise, even without the features of a claimed claim, with their features independent inventive 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 comprise one or a plurality of the features described in the above description, in particular with features provided with reference symbols and/or specified in the list of reference symbols. The invention also relates to forms in which individual of the features mentioned in the above description are not implemented, in particular insofar as they are recognizably dispensable for the respective purpose, or can be replaced by other technically equivalent means.

LIST OF REFERENCE SYMBOLS

(25) 1 Process chamber 2 Gas inlet device 3 Susceptor 4 Substrate 5 Transmitter coil 6 End 7 End 8 Cavity 9 Coating