Connection assembly, plasma process flow supply system, plasma process system and method for operating plasma process

Abstract

The invention relates to a connection assembly (1) for limiting mass and maintaining bandwidth for a plasma process flow supply system (10), comprising: a) a first inner conductor (2) which is designed to provide a first DC voltage by means of a first DC power source (5); b) a second inner conductor (4) which is designed to provide a second DC voltage by means of a second DC power source (8); and (c) an outer conductor (9) surrounding the two inner conductors (2, 4) to shield the two inner conductors and to display a reference potential of the two inner conductors (2, 4), in which d) the connection assembly (1) is designed to be connected to: i. A plasma process assembly (6), a DC power source (5, 8) and an HF power source (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 source (5, 8) and an HF power source (9); and e) the connection assembly (1) is designed to guide an HF power signal associated with the outer conductor (9) via the two inner conductors (2, 4) in order to supply HF power to the plasma process assembly (6) by means of the HF power source (3).

Description

Technical Field

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

[0002] Such a plasma process flow supply system may, for example, be part of a plasma process system in which electrical power is supplied to plasma process components by means of a plurality of power supplies.

[0003] Such a plasma process component can be, for example, a plasma process chamber for industrial plasma processes such as workpiece surface treatment, semiconductor production using plasma, or workpiece processing using gas lasers.

[0004] In such applications, plasma process components are used to generate plasma.

[0005] For this purpose, the plasma process component can have two electrodes, which are fed with two DC voltages, for example for supplying an electrostatic chuck, and a high-frequency power signal, hereinafter referred to as an HF power signal, for generating the plasma.

[0006] Typically, a plasma process assembly is connected to a plurality of DC power supplies and a high frequency power supply, which is referred to as an HF power supply in the following.

[0007] Plasma processes carried out in plasma process modules have the following problem: the electrical load impedance of the plasma process module occurring during the process depends on the conditions in the plasma process module and can vary significantly. In particular, the characteristics of the workpiece, the electrode, and the gas conditions are taken into account.

[0008] Therefore, an impedance matching circuit is usually required to convert the impedance of the load to the nominal impedance of the HF power supply. Such an impedance matching circuit is usually placed between the HF power supply and the plasma process component, usually in close proximity to the plasma process component.

[0009] In addition to the impedance matching circuit, the plasma process stream supply system may also include one or more filters in one or more filter boxes having circuits for preventing unwanted currents, particularly reverse currents, at frequencies different from the desired frequency.

[0010] Such a filter box can be a circuit assembly arranged in a housing having multiple inputs for connecting, for example, multiple power supplies with different operating frequencies, one or more outputs, and one or more filter circuits. For example, a DC power supply, an AC power supply, and / or an HF power supply can be connected to the input.

[0011] Filter circuits ensure that connected power supplies do not interfere with each other by protecting them from unwanted currents of different frequencies relative to the input.

[0012] For this purpose, the filter circuit preferably has inductors and / or capacitors, which are usually very expensive for the application in question due to the required current and voltage load capacity and the need for cooling.

[0013] The filter box may be positioned between the impedance matching circuit and the plasma process components.

[0014] All these components such as DC power supplies, HF power supplies or filter boxes, especially impedance matching circuits and plasma process components, must be connected together in the plasma process flow supply system.

[0015] When fed with three different signals, such connections in conventional components imply a certain degree of design complexity, since separate lines are used for each signal.

[0016] Besides the design complexity of such a connection assembly, this also results in the cost of three connection lines.

[0017] Purpose of the Invention

[0018] The invention is therefore based on the object of providing a connection assembly for a plasma process stream supply system which simplifies the design of the plasma process stream supply system. Summary of the Invention

[0019] This problem is solved by a connecting assembly according to independent claim 1. Advantageous further developments of the invention follow from the dependent claims and / or the description.

[0020] According to the present invention, a connection assembly for a plasma process flow supply system is provided, the connection assembly comprising:

[0021] a) a first inner conductor, which is designed to be supplied with a first DC voltage by means of a first DC power source,

[0022] b) a second inner conductor, which is designed to be supplied with a second DC voltage by means of a second DC power source,

[0023] c) an outer conductor, which surrounds the two inner conductors to shield the two inner conductors and to exhibit a reference potential to the two inner conductors,

[0024] d) wherein the connection component is designed to be connected to:

[0025] i. Plasma process components and two DC power supplies and one HF power supply or

[0026] ii. Impedance matching circuits and plasma process components and / or

[0027] iii. Impedance matching circuit, DC power supply and HF power supply;

[0028] e) wherein the connection component is designed to conduct an HF power signal associated with the outer conductor via two inner conductors in order to supply HF power to the plasma process component by means of an HF power supply.

[0029] The connection assembly combines the provision of two DC voltages and the transmission of an HF power signal in a common component, thereby simplifying the design of the plasma process flow supply system. Here, an HF power signal is understood to mean a power signal with a power level of ≥500 W, particularly ≥1 kW, and particularly preferably ≥3 kW. HF stands for high frequency. In the field of plasma processing, HF refers to frequencies ≥2 MHz, but particularly ≥10 MHz and ≤200 MHz.

[0030] Such plasma process stream supply systems usually have two DC power supplies, an HF power supply, and connection components for connecting possible loads.

[0031] For example, a possible load may be a plasma process component, such as a plasma process chamber having two electrodes, which typically require two DC signals, for example for use as an electrostatic chuck, and one HF signal, for example for generating the plasma.

[0032] Optionally, additional components such as impedance matching circuits or circuits or components as protective measures may also be part of the plasma process flow supply system. As protective measures, one or more inductors and / or capacitors, in particular one or more DC blocking capacitors or HF blocking inductors, may be used. DC blocking capacitors are capacitors designed and arranged to block DC currents. HF blocking inductors are inductors designed and arranged to significantly reduce, and in particular block, HF currents. Thus, these components can prevent unwanted DC or HF return currents.

[0033] A DC power supply is a power supply designed to provide power with DC voltage and DC current. This power can be pulsed or bipolar pulsed.

[0034] The reference potential is a voltage that has a constant potential relative to ground over multiple cycles of the HF signal. In particular, it is ground potential itself.

[0035] To use the connection assembly in a plasma process stream supply system, the inner conductors of the connection assembly can each be connected to a different DC power source, and additionally, both inner conductors can be connected together to an HF power source.

[0036] This enables a potential load, such as a plasma process chamber, to be supplied with three different signals via a single common component without the need for a complex design of multiple cables and connectors.

[0037] The connection assembly can be designed such that the HF power signal in such an assembly can be coupled in common mode to the two inner conductors via capacitive coupling. Thus, the connection assembly for the HF power signal behaves externally like a conventional coaxial cable, which makes it possible, for example, to use typical contactless current and / or voltage sensors for AC voltages, in particular HF signals.

[0038] On the one hand, the connection component is designed for a predefinable HF impedance. This HF impedance can depend in particular on the impedance of the intended connection of the connection component.

[0039] Thus, when connected to a plasma process assembly, the impedance may be equal to the impedance of the plasma process assembly, and when connected to an impedance matching circuit, the impedance may be equal to the impedance of the impedance matching circuit.

[0040] If the connecting component is a coaxial cable, for example, the impedance is determined by the inner diameter of the outer cable and the outer diameter of the inner cable, as well as the dielectric. The inner conductor can, for example, have a substantially circular outer diameter. The inner diameter of the outer conductor can be adjustable. This allows the impedance of the cable to be adjusted according to the specifications.

[0041] Furthermore, the connection assembly can be designed to include a dielectric. This dielectric can be placed between two inner conductors or between an inner conductor and an outer conductor. The material of the dielectric between the two inner conductors can be different from the material of the dielectric between the inner conductor and the outer conductor. For example, a solid material can be placed between the inner conductors, which can also serve as a support for the two inner conductors. Between the inner and outer conductors, air, liquid, or a combination of these and a solid material can be used to insulate the various conductors from each other.

[0042] Such a solid dielectric can preferably be made of a material that is compatible with other possible materials in terms of their properties, such as relative permittivity and loss factor. For example, the material used can be PTFE (polytetrafluoroethylene) or aluminum oxide. In addition, when the two inner conductors are excited in common mode, the HF electric field is mainly formed between the inner conductor and the outer conductor. This means that if the two inner conductors are only a short distance apart, are at the same HF potential, and differ only substantially in their DC potential, the material of the dielectric between the surfaces of the inner conductors has only a very small effect on the properties of the connection component. This can further enhance the effect that the connection component for HF power signals functions like a conventional coaxial cable. For example, a small distance here means a distance of less than or equal to 3 mm, in particular less than or equal to 1 mm, and particularly preferably less than or equal to 0.5 mm.

[0043] The connection component can have a current sensor, a voltage sensor, or a combined current and voltage sensor, in particular for determining the transmitted HF voltage and the transmitted HF current. This enables monitoring of the HF power signal to be integrated into the component.

[0044] Such a sensor can be arranged to surround the two inner conductors of the coaxial cable.In this way, the HF voltage and / or the HF current can be determined even if the HF voltage and / or the HF current is distributed across the two inner conductors.

[0045] The connection assembly may include 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 Pat. No. 7,755,451 B2 and US Pat. No. 10,490,876 B2.

[0046] 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, which are separated from each other by a dielectric. This embodiment offers the advantage of a uniform electric field between the inner conductor and the outer conductor of the connection assembly.

[0047] In one embodiment, the connection assembly has more than two inner conductors, each of which is separated from one another by a dielectric and together form a circular cross-section. In this way, more than two DC voltages can be supplied to the plasma with low losses and a predeterminable impedance.

[0048] The connection assembly may be used in various locations in a system, such as a plasma process stream supply system or a plasma process system.

[0049] Thus, embodiments of a plasma process stream supply system may include a first DC power supply, a second DC power supply, an HF power supply, a plurality of DC blocking capacitors and an HF blocking inductor, and a connecting assembly. In such a system, connections are established between the first DC power supply and a first inner conductor of the connecting assembly, between the second DC power supply and a second inner conductor of the connecting assembly, and between the HF power supply and both inner conductors. The HF blocking inductor is disposed between the DC power supply and the inner conductor of the connecting assembly. The DC blocking capacitor is disposed between the HF power supply and the inner conductor of the connecting assembly.

[0050] A load requiring the supply of these three signals, such as a plasma process component, can then be connected to the connection component.

[0051] Such a plasma process supply system may also have an impedance matching circuit, which may be connected to the connection assembly. The connection assembly may then be used to connect a possible load to the impedance matching circuit.

[0052] Such an overall system, in which a load in the form of a plasma process component is connected to the described plasma process stream supply system, may then be referred to as a possible embodiment of a plasma process system.

[0053] Furthermore, a connection assembly may be used in a portion of a plasma process system. Such a portion of a plasma process system may include an impedance matching circuit, a plasma process component, and a connection assembly. Here, the connection assembly may establish a connection between the impedance matching circuit and the plasma process component. The connection assembly enables the plasma process component to be supplied with two DC voltages and an HF power signal, which may be provided by two DC power supplies and one HF power supply. The HF power supply may be connected to the connection assembly via the impedance matching circuit. There are various options for feeding the two DC power supplies. On the one hand, the two DC power supplies may be connected to the connection assembly via the impedance matching circuit. On the other hand, the DC power supply may be connected to the connection assembly after the impedance matching circuit. By feeding the impedance matching circuit, the impedance matching circuit may be moved closer to the plasma process component, which may provide advantages in terms of bandwidth and impedance matching. Feeding the impedance matching circuit after the impedance matching circuit has the following advantages: if the impedance matching circuit already has protective measures such as DC blocking capacitors, these protective measures outside the impedance matching circuit may be omitted.

[0054] Furthermore, a connection assembly can be used in a method for operating a plasma process in a plasma process assembly, in particular a plasma process assembly according to the previously described method. The connection assembly can be part of a plasma process system, in particular a plasma process system as described previously. Such a method can have multiple steps. First, two DC voltages and an HF power signal can be supplied to the plasma process assembly. To this end, the first DC voltage can be supplied by a first DC power supply via a first inner conductor of the connection assembly of the plasma process assembly. Simultaneously, the second DC voltage can be supplied by a second DC power supply via a second inner conductor of the connection assembly of the plasma process assembly. Simultaneously, the HF power signal can be transmitted from the HF power supply to the plasma process assembly via the two inner conductors of the connection assembly while these two voltages are supplied.

[0055] Follow these steps to generate plasma in a plasma process component. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The schematic diagrams illustrate an embodiment of the invention in various stages of use and are explained in more detail in the following description.

[0057] In the attached figure:

[0058] Figure 1 Shown are connection components arranged in a plasma processing system.

[0059] Figures 2a to 2dA number of different plasma process fluid supply systems and plasma process systems utilizing connection assemblies are shown.

[0060] Figure 3 A connection assembly with a sensor is shown. DETAILED DESCRIPTION

[0061] Figure 1 A first embodiment of a connection assembly 1 according to the present invention is shown for an exemplary plasma process stream supply system 10 arranged in an exemplary plasma process system 12. The connection assembly 1 has two inner conductors 2, 4 and an outer conductor 9 and is part of the plasma process stream supply system 10. The plasma process stream supply system 10 also has two DC power supplies 5, 8, an HF power supply 3, and an impedance matching circuit 7 and is part of the plasma process system 12. The plasma process system 12 also has a plasma process assembly 6.

[0062] The connection component 1 connects the impedance matching circuit 7 and the plasma process component 6 .

[0063] The inner conductors 2 and 4 in the connection assembly 1 are designed to provide two DC voltages and transmit an HF power signal. Each inner conductor 2 and 4 can be supplied with a different DC voltage, and the HF power signal can be coupled to both inner conductors 2 and 4. These signals are associated with the outer conductor 9 of the connection assembly 1 and are provided by two DC power supplies 5 and 8 and an HF power supply 3. These signals are intended to be fed to two electrodes in the plasma processing assembly 6. By supplying these electrodes with DC power, they can be used as electrostatic chucks, and by using the HF power signal at the electrodes to generate plasma.

[0064] The impedance matching circuit 7 converts the impedance of the plasma process component 6 to the nominal impedance of the HF power supply 3, since the impedance of the plasma process component 6 may vary greatly during the plasma process. In addition, the impedance matching circuit 7 may include further components for filtering unwanted reverse currents, such as DC blocking capacitors C1, C2 or HF blocking inductors L1, L2.

[0065] The two DC power sources 5 , 8 and the HF power source 3 are connected to an impedance matching circuit 7 , via which they are also connected to the inner conductors 2 , 4 of the connection assembly 1 .

[0066] Figure 2a A possible arrangement of an embodiment of the connection assembly 1 according to the invention in a plasma processing system is shown.

[0067] The plasma process system comprises two DC power supplies 5 and 8 , an HF power supply 3 , a plasma process component 6 and a connecting component 1 .

[0068] The connection assembly 1 is arranged between the power sources 3, 5, 8 and the plasma process component 6. Via the connection assembly 1, the plasma process component 6 is supplied with two DC voltages and an HF power signal from the power sources 3, 5, 8.

[0069] HF blocking inductors L1 and L2 are inserted between the DC power sources 5 and 8 and the connection assembly 1. DC blocking capacitors C1 and C2 are inserted between the HF power source 3 and the connection assembly 1. These components serve as a protective measure against unwanted reverse currents.

[0070] Figure 2b A possible arrangement of an embodiment of the connection assembly 1 according to the invention in a part of an exemplary plasma processing system is shown.

[0071] A portion of the plasma process system includes an impedance matching circuit 7 , a plasma process component 6 , and a connection component 1 .

[0072] The connection assembly 1 is arranged between the impedance matching circuit 7 and the plasma process assembly 6. The connection assembly 1 enables the plasma process assembly 1 to be supplied with two DC voltages and one HF power signal, which can be provided by two DC power supplies 5, 8 and one HF power supply 3.

[0073] The HF power supply 3 may be connected to an impedance matching circuit 7 .

[0074] The two DC voltages can be fed in before or in the impedance matching circuit 7 or after the impedance matching circuit via the DC power supplies 5, 8. Feeding in before or in the impedance matching circuit 7 offers design advantages, since the impedance matching circuit 7 can be moved closer to the plasma process component 6, which can also offer advantages in terms of impedance matching and bandwidth.

[0075] When feeding after the impedance matching circuit 7 , if the impedance matching circuit 7 already provides protection measures such as DC blocking capacitors, these protection measures are no longer required outside the impedance matching circuit 7 .

[0076] Figure 2c A possible arrangement of an embodiment of the connection assembly 1 according to the invention in an exemplary plasma process stream supply system is shown.

[0077] The plasma process flow supply system comprises an impedance matching circuit 7 , two DC power supplies 5 , 8 , an HF power supply 3 and a connection component 1 .

[0078] The connection component 1 is arranged between the power sources 3, 5, 8 and the impedance matching circuit 7. Two DC voltages and an HF power signal can be fed into the impedance matching circuit 7 via the connection component 1. These signals are provided by the power sources 3, 5, 8.

[0079] HF blocking inductors L1 and L2 are inserted between the DC power sources 5 and 8 and the connection assembly 1. DC blocking capacitors C1 and C2 are inserted between the HF power source 3 and the connection assembly 1. These components serve as a protective measure against unwanted reverse currents.

[0080] A load requiring two DC voltages and an HF power signal, such as a plasma process chamber, can be connected to the impedance matching circuit.

[0081] Figure 2d A further possible arrangement of an embodiment of the connection assembly 1 according to the invention in an exemplary plasma processing system is shown.

[0082] The plasma process system comprises a plasma process component 6 , an impedance matching circuit 7 , two DC power supplies 5 , 8 , an HF power supply 3 and a connection component 1 .

[0083] The connection component 1 is arranged once between the plasma process component 6 and the impedance matching circuit 7 , and once between the impedance matching circuit 7 and the power sources 3 , 5 , 8 .

[0084] The plasma process component 6 is supplied with two DC voltages and an HF power signal via the connection component 1. These signals are provided by the power supplies 3, 5, 8.

[0085] HF blocking inductors L1 and L2 are inserted between the DC power sources 5 and 8 and the connection assembly 1. DC blocking capacitors C1 and C2 are inserted between the HF power source 3 and the connection assembly 1. These components serve as a protective measure against unwanted reverse currents.

[0086] The impedance matching circuit 7 converts the load impedance of the plasma process component 6 into the nominal impedance of the HF power device 3 .

[0087] Figure 3 An embodiment of a connection assembly 1 according to the invention is shown with a combined sensor, in particular a current and voltage sensor 13. For example, a current sensor in such an application is described in US 7,321,227 B2. This can be supplemented by an additional voltage sensor, such as a capacitive voltage sensor. For example, such a combined current and voltage sensor 13 is described in US 2012 / 0223697 A1. In addition to the current and voltage sensor 13, Figure 3 Also shown are the two inner conductors 2 , 4 and the outer conductor 9 in the connection assembly 1 .

[0088] The connection assembly 1 may also include 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 Pat. No. 7,755,451 B2 and US Pat. No. 10,490,876 B2.

[0089] exist Figure 3 In FIG, dielectrics 11 between the inner conductors 2, 4 and between the inner conductors 2, 4 and the outer conductor 9 are also shown.

Claims

1. A connection assembly (1) for a plasma process flow supply system (10), the connection assembly comprising: a) a first inner conductor (2) designed to be supplied with a first DC voltage by means of a first DC power source (5), b) a second inner conductor (4), which is designed to be supplied with a second DC voltage by means of a second DC power supply (8), c) an outer conductor (9) surrounding the two inner conductors (2, 4) to shield the two inner conductors and to exhibit a reference potential of the two inner conductors (2, 4), d) wherein the connection assembly (1) is designed to be connected to: i. Plasma process component (6), the DC power supply (5, 8) and the HF power supply (9) or ii. Impedance matching circuit (7) and plasma process component (6) and / or iii. Impedance matching circuit (7), the DC power supply (5, 8) and the HF power supply (3); e) Among them, The connection component (1) is designed to guide the HF power signal associated with the outer conductor (9) via the two inner conductors (2, 4) in order to supply HF power to the plasma process component (6) by means of the HF power supply (3).

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

3. Connection assembly (1) according to one of the preceding claims, wherein The connection component (1) comprises a dielectric (11) which is arranged: i. Between the two inner conductors (2, 4) and ii. Between the inner conductor (2, 4) and the outer conductor (9).

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. Connection assembly (1) according to one of the preceding claims, wherein The connecting component (1) has a sensor (13), which is designed in particular as a current sensor, a voltage sensor and / or a combined current and voltage sensor.

6. Connection assembly (1) according to one of the preceding claims, 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. Connection assembly (1) according to one of the preceding claims, wherein The connecting component (1) is designed for a predefinable HF impedance, which is based in particular on the impedance of the intended connection of the connecting component (1).

8. A plasma process flow supply 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 one of the preceding claims, wherein the plasma process flow supply system establishes the following connection: a) connecting the first DC power source (5) to the first inner conductor (2) of the connecting assembly (1); b) connecting the second DC power supply (8) to the second inner conductor (4) of the connection assembly (1); c) Connection of the HF power source (3) to the two inner conductors (2, 4) of the connection assembly (1).

9. The plasma process flow supply system (10) according to claim 8, comprising an impedance matching circuit (7) which can be connected to the power supply (3, 5, 8) by means of the connection component (1).

10. The plasma process stream supply system (10) according to claim 9, wherein: A further connection component (1) is connected to the impedance matching circuit (7) for connection to a possible load such as a plasma process chamber.

11. A plasma process system (12) having a plasma process stream supply system (10) according to one of the preceding claims 8 to 10 and a plasma process component (6) connected via a connecting component (1) according to one of claims 1 to 7, the component having two electrodes for connecting in each case one of the two inner conductors (2, 4).

12. A plasma process system, a part of which comprises an impedance matching circuit (7), a plasma process component (6) and a connection component (1) according to one of the preceding claims 1 to 7, which establishes a connection between the impedance matching circuit (7) and the plasma process component (6).

13. A method for operating a plasma process in a plasma process component (6) in a plasma process system (12) according to claim 11, the method comprising the following steps: a) supplying a first DC voltage to the plasma process component (6) via the first inner conductor (2) of the connecting component (1) by means of a first DC power supply (5), b) supplying a second DC voltage to the plasma process component (6) via the second inner conductor (4) of the connecting component (1) by means of a second DC power supply (8), c) transmitting an HF power signal from the HF power supply (3) to the plasma process component (6) via the two inner conductors (2, 4) of the connecting component (1) d) generating plasma in the plasma process component (6).

Images