Connection assembly, plasma process flow delivery system, plasma processing system, and method for operating a plasma process - Patents.com

Abstract

The present invention provides a connection assembly (1) for limiting quality and maintaining bandwidth for a plasma process flow delivery system (10), comprising: a) a first inner conductor (2) designed to provide a first DC voltage by a first DC power source (5); b) a second inner conductor (4) designed to provide a second DC voltage by a second DC power source (8); c) an outer conductor (9) surrounding the two inner conductors (2, 4) to shield them and indicating a reference potential for the two inner conductors (2, 4); and d) a connection assembly (1) for limiting quality and maintaining bandwidth for a plasma process flow delivery system (10), the connection assembly (1) comprising: ) is designed to be connected to i. a plasma process assembly (6), a DC power supply (5, 8), and an HF power supply (9), or ii. an impedance matching circuit (7) and a plasma process assembly (6), and / or iii. an impedance matching circuit (7), a DC power supply (5, 8), and an HF power supply (9), and e) the connection assembly (1) is designed to induce an HF power signal associated with the outer conductor (9) via the two inner conductors (2, 4) to supply HF power to the plasma process assembly (6) by the HF power supply (3).

Description

[Technical Field]

[0001] The present invention relates to a connection assembly for a plasma process flow delivery system, a plasma process flow delivery system, a plasma processing system, and a method for operating a plasma process.

[0002] Such a plasma process flow delivery system may, for example, be part of a plasma processing system in which the plasma processing assembly is powered by multiple power supplies.

[0003] Such a plasma processing assembly may be, for example, a plasma processing chamber used for industrial plasma processes such as surface treatment of a workpiece, semiconductor manufacturing using plasma, or treatment of a workpiece using a gas laser.

[0004] In such applications, the plasma processing assembly functions to generate a plasma.

[0005] For this purpose, the plasma processing assembly may have, for example, two electrodes to which two DC voltages for supplying the electrostatic chuck and a high frequency power signal (hereinafter referred to as HF power signal) for generating the plasma are fed.

[0006] Typically, the plasma processing assembly is connected to a number of DC power sources and radio frequency power sources (hereafter referred to as HF power sources).

[0007] Plasma processes performed within a plasma processing assembly present a problem in that the electrical load impedance of the plasma processing assembly that is generated during the process can vary significantly depending on the conditions within the plasma processing assembly, particularly considering the workpiece characteristics, electrode, and gas conditions.

[0008] Therefore, an impedance matching circuit is typically required to transform the impedance of the load to the nominal impedance of the HF power source. Such an impedance matching circuit is typically located between the HF power source and the plasma processing assembly, typically in close proximity to the plasma processing assembly.

[0009] In addition to the impedance matching circuit, the plasma process flow delivery system may also be provided with a filter in one or more filter boxes that contain electrical circuits that function to protect against undesired currents, particularly reverse currents, that have frequencies different from the useful frequencies.

[0010] Such a filter box may be, for example, a circuit assembly disposed within a housing having multiple inputs for connecting multiple power sources having different operating frequencies, one or more outputs, and one or more filter circuits. For example, DC, AC, and / or HF power sources may be connected to the inputs.

[0011] The filter circuit ensures that connected power supplies do not interfere with each other by protecting the power supplies from unwanted currents at different frequencies than the input.

[0012] To this end, the filter circuit preferably has inductance and / or capacitance, which are often very expensive for the application in question due to the required current and voltage load capacity and cooling needs.

[0013] The filter box may be disposed between the impedance matching circuit and the plasma processing assembly.

[0014] All these components, such as the DC power supply, the HF power supply or the filter box, specifically the impedance matching circuit and the plasma process assembly, must be connected together in a plasma process flow delivery system.

[0015] When three different signals are being fed, such connections in conventional assemblies imply a level of design complexity, as separate lines are used for each signal.

[0016] In addition to the complexity of designing such a connection assembly, this also results in the cost of three connection lines. [Background technology]

[0017] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a connection assembly for a plasma process flow delivery system that simplifies the design of the plasma process flow delivery system.

[0018] Summary of the Invention This problem is solved by a connection assembly according to independent claim 1. Advantageous further developments of the invention emerge from the dependent claims and / or the description.

[0019] In accordance with the present invention, there is provided a connection assembly for a plasma process flow delivery system, comprising: a) a first inner conductor designed to provide a first DC voltage via a first DC power source; b) a second inner conductor designed to provide a second DC voltage via a second DC power source; c) an outer conductor surrounding the two inner conductors to shield the two inner conductors and indicating the reference potential of the two inner conductors; d) a connection assembly comprising: i. A plasma process assembly, two DC power supplies, and one HF power supply; or ii. Impedance matching circuits and plasma process assemblies; and / or iii. It is designed to be connected to an impedance matching circuit, a DC power source, and an HF power source; e) A connection assembly is proposed, the connection assembly being designed to induce an HF power signal associated with an outer conductor via two inner conductors in order to supply HF power to a plasma processing assembly by an HF power source.

[0020] The connection assembly combines the provision of two DC voltages and the transmission of an HF power signal in a common assembly, thereby simplifying the design of a plasma process flow delivery system. Here, HF power signal refers to a power signal having a power level of 500 W or more, specifically 1 kW or more, and particularly preferably 3 kW or more. HF means high frequency. In the field of plasma processing, HF refers to frequencies of 2 MHz or more, but specifically refers to frequencies of 10 MHz or more and 200 MHz or less.

[0021] Such plasma process flow delivery systems typically include a connection assembly for connecting two DC power sources, an HF power source, and a possible load.

[0022] A possible load could be, for example, a plasma processing assembly, such as a plasma processing chamber with two electrodes, which typically require the supply of two DC signals and one HF signal, the former for use as, for example, an electrostatic chuck, and the latter for, for example, plasma generation.

[0023] Optionally, additional components, such as an impedance matching circuit or component as a protection means, can also be part of the plasma process flow delivery system. One or more inductances and / or capacitances, specifically one or more DC blocking capacitances or HF blocking inductances, can be used as a protection means. A DC blocking capacitance is a capacitance designed and arranged to block DC current. An HF blocking inductance is an inductance designed and arranged to significantly reduce, specifically block, HF current. These components can thereby protect against undesired DC return currents or HF return currents.

[0024] A DC power supply is a power supply designed to provide power having a direct current voltage and current, which can be pulsed or bipolar pulsed.

[0025] The reference potential refers to a voltage potential that has a constant potential relative to ground over multiple periods of the HF signal. Specifically, it is ground itself.

[0026] To use the connection assembly in a plasma process flow delivery system, the inner conductors of the connection assembly can each be connected to a different DC power source, and in addition, both inner conductors can be connected together to an HF power source.

[0027] This allows a potential load, such as a plasma process chamber, to be supplied with three different signals through a single common assembly without requiring a complex design of multiple cables and connectors.

[0028] The connection assembly can be designed so that the HF power signal in such an assembly can be coupled to both inner conductors in common mode via capacitive coupling. As a result, the connection assembly for HF power signals acts from the outside like a conventional coaxial cable, which makes it possible to use, for example, typical non-contact current and / or voltage sensors for AC voltages, specifically HF signals.

[0029] In one aspect, the connection assembly is designed for a determinable HF impedance, which may depend specifically on the impedance of the connection assembly's intended connection.

[0030] Thus, in the case of a connection to a plasma processing assembly, the impedance may be equal to the impedance of the plasma processing assembly, and in the case of a connection to an impedance matching circuit, the impedance may be equal to the impedance of the impedance matching circuit.

[0031] If the connection assembly is, for example, a coaxial cable, the impedance is determined by the inner diameter of the outer cable and the outer diameter of the inner cable and dielectric. The inner conductor can have, for example, a substantially circular outer diameter. The outer conductor has an adjustable inner diameter. This allows the cable impedance to be set according to specifications.

[0032] Furthermore, the connection assembly can be designed with a dielectric. This dielectric can be disposed between the two inner conductors or between the inner conductor and the outer conductor. The dielectric material can be different between the two inner conductors and between the inner conductor and the outer conductor. For example, a solid material can be disposed between the inner conductors, and this solid material can also function as a holder for the two inner conductors. For example, air, liquid, or a combination of both solid materials can be used between the inner conductor and the outer conductor to insulate the various conductors from each other.

[0033] Such a solid dielectric material preferably has properties, such as dielectric constant and loss angle, that are compatible with other possible materials. For example, the material used can be PTFE (polytetrafluoroethylene) or aluminum oxide. Additionally, when both inner conductors are excited in common mode, the HF field is primarily formed between the inner and outer conductors. This means that the dielectric material between the surfaces of the inner conductors has very little effect on the characteristics of the connection assembly when the two inner conductors are only a short distance apart, are at the same HF potential, and differ substantially only in DC potential. This further enhances the effectiveness of the connection assembly for HF power signals, which functions like a conventional coaxial cable. Here, a short distance means, for example, a distance of 3 mm or less, specifically 1 mm or less, and particularly preferably 0.5 mm or less.

[0034] The connection assembly may have a current sensor, a voltage sensor, or a combined current and voltage sensor, in particular to determine the transmitted HF voltage and the transmitted HF current, which allows monitoring of the HF power signal to be integrated into the assembly.

[0035] Such sensors can be arranged to surround the two inner conductors of a coaxial cable, thus allowing the HF voltage and / or HF current to be determined even if it is distributed across both inner conductors.

[0036] The connection assembly may comprise a sensor for determining the forward and / or reverse power. Such a sensor may be designed, for example, as a directional coupler. Such directional couplers are described, for example, in US 7,755,451 B2 and US 10,490,876 B2.

[0037] In a further embodiment of the connection assembly, the inner conductor can be designed in the form of two conductor halves with a semicircular cross section separated from each other by a dielectric, which provides the advantage of a uniform electric field between the inner and outer conductors of the connection assembly.

[0038] In one embodiment, the connection assembly has two or more inner conductors, each separated from the others by a dielectric and together forming a circular cross section, such that two or more DC voltages can be delivered to the plasma with low loss and definable impedance.

[0039] The connection assembly can be used in a variety of locations within a system, such as a plasma process flow delivery system or a plasma processing system.

[0040] Thus, embodiments of plasma process flow delivery systems can include, in addition to the connection assembly, a first DC power source, a second DC power source, an HF power source, and a plurality of DC blocking capacitors and HF blocking inductances. In such systems, connections are made between the first DC power source and a first inner conductor of the connection assembly, between the second DC power source and a second inner conductor of the connection assembly, and between the HF power source and the two inner conductors. The HF blocking inductance is disposed between the DC power source and the inner conductor of the connection assembly. The DC blocking capacitor is disposed between the HF power source and the inner conductor of the connection assembly.

[0041] A load, such as a plasma process assembly, requiring the supply of these three signals can then be connected to the connection assembly.

[0042] Such a plasma process supply system may further include an impedance matching circuit that can be connected to the connection assembly. A possible load can then be connected to the impedance matching circuit using the connection assembly.

[0043] Such an entire system, in which a load in the form of a plasma processing assembly is connected to the described plasma process flow delivery system, can be referred to as a possible embodiment of a plasma processing system.

[0044] Furthermore, the connection assembly can be used in a portion of a plasma processing system. Such a portion of the plasma processing system may include an impedance matching circuit, a plasma processing assembly, and a connection assembly. Here, the connection assembly can establish a connection between the impedance matching circuit and the plasma processing assembly. The connection assembly allows the plasma processing assembly to be supplied with two DC voltages and one HF power signal, which can be provided by two DC power sources and one HF power source. The HF power source can be connected to the connection assembly through the impedance matching circuit. There are several options for feeding the two DC power sources. On the one hand, the two DC power sources can be connected to the connection assembly through the impedance matching circuit. On the other hand, the DC power source can be connected to the connection assembly after the impedance matching circuit. By feeding through the impedance matching circuit, the impedance matching circuit can be moved closer to the plasma processing assembly, which can provide advantages in terms of bandwidth and impedance matching. Infeeding after the impedance matching circuit has the advantage that protective measures, such as DC blocking capacitors outside the impedance matching circuit, can be omitted if the impedance matching circuit already has them.

[0045] Furthermore, the connection assembly can be used in a method for operating a plasma process in a plasma processing assembly, particularly in accordance with the plasma processing assembly described above. The connection assembly can be part of a plasma processing system, particularly the plasma processing system described above. Such a method can have multiple steps. First, the plasma processing assembly can be supplied with two DC voltages and an HF power signal. To this end, a first DC voltage can be provided by a first DC power source via a first inner conductor of the connection assembly of the plasma processing assembly. Simultaneously, a second DC voltage can be provided by a second DC power source via a second inner conductor of the connection assembly of the plasma processing assembly. Simultaneously with these two provisionings, an HF power signal can be transmitted from the HF power source to the plasma processing assembly via both inner conductors of the connection assembly.

[0046] Following these steps, a plasma can be generated in the plasma processing assembly.

[0047] The schematic diagrams show embodiments of the invention in various stages of use, which are explained in more detail in the following description. [Brief explanation of the drawings]

[0048] In the drawings, [Figure 1] FIG. 1 illustrates a connection assembly disposed in a plasma processing system. [Figure 2] 2a-2d are diagrams illustrating a plasma processing system with several different plasma process flow delivery systems and connection assemblies. [Figure 3] FIG. 1 illustrates a connection assembly with a sensor. DETAILED DESCRIPTION OF THE INVENTION

[0049] 1 illustrates a first embodiment of a connection assembly 1 according to the present invention for an exemplary plasma process flow delivery system 10 disposed within an exemplary plasma processing system 12. The connection assembly 1 includes two inner conductors 2, 4 and an outer conductor 9 and is part of the plasma process flow delivery system 10. The plasma process flow delivery system 10 additionally includes two DC power supplies 5, 8, an HF power supply 3, and an impedance matching circuit 7 and is part of a plasma processing system 12. The plasma processing system 12 additionally includes a plasma processing assembly 6.

[0050] The connection assembly 1 connects the impedance matching circuit 7 and the plasma processing assembly 6 .

[0051] The inner conductors 2, 4 of the connection assembly 1 are designed to provide two DC voltages and to transmit an HF power signal. Each inner conductor 2, 4 can provide a different DC voltage, and an HF power signal can be coupled to both inner conductors 2, 4. These signals are associated with the outer conductor 9 of the connection assembly 1 and are provided by two DC power sources 5, 8 and an HF power source 3. The purpose of the signals is to feed two electrodes in the plasma processing assembly 6. On the one hand, these electrodes can be used as electrostatic chucks by feeding them with DC power, and on the other hand, a plasma can be generated at the electrodes using an HF power signal.

[0052] The impedance matching circuit 7 converts the impedance of the plasma processing assembly 6 to the nominal impedance of the HF power supply 3, since the impedance of the plasma processing assembly 6 can vary significantly during the plasma process. In addition, the impedance matching circuit 7 may incorporate further assemblies such as DC blocking capacitors C1, C2 or HF blocking inductances L1, L2 for filtering undesired reverse currents.

[0053] The two DC power sources 5, 8 and the HF power source 3 are connected to an impedance matching circuit 7 and are also connected to the inner conductors 2, 4 of the connection assembly 1 through the impedance matching circuit 7.

[0054] FIG. 2a shows a possible arrangement of an embodiment of a connection assembly 1 according to the invention in a plasma processing system.

[0055] The plasma processing system includes two DC power supplies 5, 8, an HF power supply 3, a plasma processing assembly 6, and a connection assembly 1.

[0056] The connection assembly 1 is disposed between the power sources 3, 5, 8 and the plasma process assembly 6. The plasma process assembly 6 is supplied with two DC voltages and an HF power signal from the power sources 3, 5, 8 via the connection assembly 1.

[0057] HF blocking inductances L1, L2 are inserted between the DC power supplies 5, 8 and the connection assembly 1. DC blocking capacitors C1, C2 are inserted between the HF power supply 3 and the connection assembly 1. These components are used as protection against unwanted reverse currents.

[0058] FIG. 2b illustrates a possible arrangement of an embodiment of a connection assembly 1 according to the present invention as part of an exemplary plasma processing system.

[0059] The portion of the plasma processing system includes an impedance matching circuit 7, a plasma processing assembly 6, and a connection assembly 1.

[0060] The connection assembly 1 is disposed between the impedance matching circuit 7 and the plasma processing assembly 6. The connection assembly 1 allows the plasma processing assembly 1 to be supplied with two DC voltages and one HF power signal, which may be provided by two DC power sources 5, 8 and one HF power source 3.

[0061] The HF power supply 3 may be connected to an impedance matching circuit 7 .

[0062] The two DC voltages can be fed via DC power supplies 5, 8 either before, into, or after the impedance matching circuit 7. Feeding before or into the impedance matching circuit 7 provides design advantages as the impedance matching circuit 7 can be moved closer to the plasma processing assembly 6, which can also provide advantages in terms of impedance matching and bandwidth.

[0063] When feeding after the impedance matching circuit 7, protection measures such as DC blocking capacitors outside the impedance matching circuit 7 are not necessary if the impedance matching circuit 7 already provides these.

[0064] FIG. 2c illustrates a possible arrangement of an embodiment of a connection assembly 1 according to the present invention in an exemplary plasma process flow delivery system.

[0065] The plasma process flow delivery system includes an impedance matching circuit 7, two DC power supplies 5, 8, an HF power supply 3, and a connection assembly 1.

[0066] The connection assembly 1 is disposed between the power sources 3, 5, 8 and the impedance matching circuit 7. Two DC voltages and an HF power signal can be fed to the impedance matching circuit 7 via the connection assembly 1. These signals are provided by the power sources 3, 5, 8.

[0067] HF blocking inductances L1, L2 are inserted between the DC power supplies 5, 8 and the connection assembly 1. DC blocking capacitors C1, C2 are inserted between the HF power supply 3 and the connection assembly 1. These components are used as protection against unwanted reverse currents.

[0068] A load such as a plasma process chamber requiring two DC voltages and an HF power signal can be connected to an impedance matching network.

[0069] FIG. 2d shows a further possibility for arranging an embodiment of the connection assembly 1 according to the present invention in an exemplary plasma processing system.

[0070] The plasma processing system includes a plasma processing assembly 6, an impedance matching circuit 7, two DC power supplies 5, 8, an HF power supply 3, and a connection assembly 1.

[0071] One connection assembly 1 is disposed between the plasma process assembly 6 and the impedance matching circuit 7, and one between the impedance matching circuit 7 and the power supplies 3, 5, 8.

[0072] The plasma process assembly 6 is supplied with two DC voltages and an HF power signal through the connection assembly 1. The signals are provided by power supplies 3, 5, 8.

[0073] HF blocking inductances L1, L2 are inserted between the DC power supplies 5, 8 and the connection assembly 1. DC blocking capacitors C1, C2 are inserted between the HF power supply 3 and the connection assembly 1. These components are used as protection against unwanted reverse currents.

[0074] The impedance matching circuit 7 transforms the load impedance of the plasma processing assembly 6 to the nominal impedance of the HF power device 3 .

[0075] FIG. 3 shows an embodiment of a connection assembly 1 according to the invention having a combined sensor, specifically a current and voltage sensor 13. A current sensor for such an application is described, for example, in US Pat. No. 7,321,227 B2. This can be supplemented by an additional voltage sensor, for example a capacitive voltage sensor. Such a combined current and voltage sensor 13 is described, for example, in US 2012 / 0223697 A1. In addition to the current and voltage sensor 13, FIG. 3 shows the two inner conductors 2, 4 and the outer conductor 9 of the connection assembly 1.

[0076] The connection assembly 1 may also comprise a sensor for determining the forward and / or reverse power. Such a sensor may be designed, for example, as a directional coupler. Such directional couplers are described, for example, in US 7,755,451 B2 and US 10,490,876 B2.

[0077] In FIG. 3, a dielectric 11 is also shown between the inner conductors 2, 4 and between the inner conductors 2, 4 and the outer conductor 9.

Claims

1. A connection assembly (1) for a plasma process flow delivery system (10), comprising: a) a first inner conductor (2) designed to provide a first direct current voltage via a first DC power source (5); b) a second inner conductor (4) designed to provide a second DC voltage via a second DC power source (8); c) an outer conductor (9) surrounding the two inner conductors (2, 4) to shield them and indicating the reference potential of the two inner conductors (2, 4); d) said connection assembly (1) i. a plasma process assembly (6), the DC power supply (5, 8), and the HF power supply (9); or ii. an impedance matching circuit (7) and a plasma processing assembly (6), and / or iii. Designed to be connected to an impedance matching circuit (7), the DC power supply (5, 8), and the HF power supply (3); e) The connection assembly (1) is designed to induce an HF power signal associated with the outer conductor (9) via the two inner conductors (2, 4) for supplying HF power to the plasma process assembly (6) by the HF power source (3).

2. 2. The connection assembly (1) according to claim 1, wherein the connection assembly (1) is designed so that the HF power signal can be coupled to both inner conductors (2, 4) in common mode via capacitive coupling.

3. The connection assembly (1) has a dielectric (11), and the dielectric (11) i. Between the two inner conductors (2, 4), and ii. The connection assembly (1) according to claim 1 or 2, disposed between the inner conductor (2, 4) and the outer conductor (9).

4. 4. The connection assembly (1) according to claim 3, wherein the material of the dielectric (11) between the two inner conductors (2, 4) is different from the material of the dielectric (11) between the inner conductor and the outer conductor (9).

5. 5. The connection assembly (1) according to any one of claims 1 to 4, wherein the connection assembly (1) comprises a sensor (13) that is specifically designed as a current sensor, a voltage sensor and / or a combined current and voltage sensor.

6. 6. A connection assembly (1) according to any one of claims 1 to 5, wherein the two inner conductors (2, 4) are designed in the form of two conductor halves with a semicircular cross section and are separated from each other by a dielectric.

7. 7. A connection assembly (1) according to any one of claims 1 to 6, wherein the connection assembly (1) is designed for a determinable HF impedance, in particular a determinable HF impedance that is based on the impedance of an intended connection of the connection assembly (1).

8. A plasma process flow delivery system (10) comprising a first DC power supply (5), a second DC power supply (8), an HF power supply (3), and a connection assembly (1) according to any one of claims 1 to 7, the system comprising the following connections: a) connecting the first DC power source (5) to the first inner conductor (2) of the connection assembly (1); b) connecting the second DC power source (8) to the second inner conductor (4) of the connection assembly (1); c) a plasma process flow delivery system (10) establishing the connection of said HF power source (3) to both inner conductors (2, 4) of said connection assembly (1).

9. 9. The plasma process flow delivery system (10) of claim 8, comprising an impedance matching circuit (7) connectable to the power source (3, 5, 8) by the connection assembly (1).

10. 10. The plasma process flow delivery system (10) of claim 9, wherein a further connection assembly (1) is connected to the impedance matching circuit (7) for connection to a possible load, for example a plasma process chamber.

11. 11. A plasma processing system (12) comprising: a plasma process flow supply system (10) according to any one of claims 8 to 10; and a plasma process assembly (6) connected via a connection assembly (1) according to any one of claims 1 to 7, the plasma process assembly (6) having two electrodes for respectively connecting one of the two inner conductors (2, 4).

12. 10. A part of a plasma processing system, comprising an impedance matching circuit (7), a plasma processing assembly (6), and a connection assembly (1) according to any one of claims 1 to 7, for establishing a connection between the impedance matching circuit (7) and the plasma processing assembly (6).

13. 12. A method for operating a plasma process in a plasma process assembly (6) of a plasma processing system (12) according to claim 11, comprising the steps of: a) providing a first DC voltage to a plasma process assembly (6) via a first inner conductor (2) of said connection assembly (1) by a first DC power source (5); b) providing a second DC voltage to the plasma process assembly (6) via a second DC power source (8) through a second inner conductor (4) of the connection assembly (1); c) transmitting an HF power signal from the HF power source (3) to the plasma process assembly (6) via the two inner conductors (2, 4) of the connection assembly (1); d) generating a plasma in said plasma processing assembly (6).

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