Impedance matching device and RF power module

Abstract

Impedance matching device (1) comprising a housing (100), an input terminal (22) and an output terminal (230), wherein a first RF capacitor (200), a second RF capacitor (201) and an RF inductor (210) are arranged in the housing (100), wherein a main fan (300) and an auxiliary fan (301) are arranged on a first side of the housing (100) such that a main air duct and an auxiliary air duct are formed in the housing (100) during operation; wherein an upper heat dissipation opening (330) is arranged in a top of the housing (100), and a side heat dissipation opening (310) is arranged on a side of the housing (100) opposite the main fan (300);wherein the main fan (300), the side heat dissipation opening (310) and the upper heat dissipation opening (330) are arranged such that they together form part of the main air duct in the housing and the main air duct passes successively by the RF inductor (210) and the output terminal (230).

Description

Technical field: The present invention relates to an impedance matching device and a power module comprising such an impedance matching device. Such a device and module are used, in particular, in plasma applications, such as plasma processing setups, especially for processing thin films, e.g., deposition or etching. Such processing steps are carried out, for example, in semiconductor manufacturing. Technical background: In a typical RF discharge plasma generation system, the output impedance of an RF power supply is usually 50 ohms, while the equivalent impedance of the plasma reaction chamber is typically not 50 ohms and also varies under different process conditions. RF here refers to frequencies above 1 MHz and, in particular, below 300 MHz. Transmission line theory indicates that if the output impedance of the RF power supply differs from the load impedance (i.e., the equivalent impedance of the plasma reaction chamber), the output power of the RF power supply is at least partially lost, and the output efficiency cannot be maximized. This can lead to energy waste and damage to the RF power supply itself. Safety problems such as fire caused by excessive local heat can also occur.Since the magnitude of the load impedance is related to the plasma generation process conditions, when using an inductively coupled plasma source, it is necessary to add an impedance matching device that can automatically adjust the load impedance between the RF power supply and the plasma reaction chamber. The impedance matching device can change the actual value of a parameter-adjustable component, such as an adjustable capacitor, via the sensor and the sensor and control system integrated into the impedance matching system, according to the actual impedance of the plasma reaction chamber under different process conditions, so that the load impedance corresponds to 50 ohms. Implement impedance matching to avoid the problems mentioned above. 1. The impedance matching device includes high-voltage and low-voltage components that are sensitive to electromagnetic interference (EMI) during operation, leading to unstable device operation and even component damage, which significantly compromises the quality of the impedance matching device. 2. With technological advancements and improved levels of integration, the impedance matching device must perform the necessary heat dissipation within a small volume. This places higher demands on the heat dissipation efficiency of the impedance matching device, requiring it to achieve better heat dissipation within the limited space to fit the system layout of this column. Referring to the technical diagram disclosed by CN217470562U, an impedance matching structure is specified that divides the high and low voltage sections by the plate body (38) to meet the requirements for anti-electromagnetic interference and employs the heat dissipation form of an independent fan to ensure the heat dissipation efficiency of the high voltage section. Application details: The application provides an impedance matching device comprising a housing, an input terminal, and an output terminal. The housing is equipped with at least two RF capacitors, and at least one RF inductor is arranged within the housing. At least one main fan and at least one auxiliary fan are arranged on one side of the housing such that, during operation, a main air duct and an auxiliary air duct are formed inside the housing.The top of the housing is equipped with a top heat dissipation opening, and the side of the housing opposite the main fan is equipped with one or more side heat dissipation openings; the main fan, the side heat dissipation opening(s) and the top heat dissipation opening together form the main air duct in the housing, and the main air duct passes successively by the RF inductor and the output terminal. The terms "input port" and "output port" each refer to an electrical connection configured to conduct electrical energy. A "fan" is also called a "ventilator." A "ventilator" is a powered machine that creates air circulation. A fan can consist of rotating blades or blades, often made of plastic or metal, that act on the air. Specifically, the fan should be configured to create an airflow from the outside to the inside of the housing, or vice versa. An "opening" in a housing component can be a hole. An opening means that air can flow through it. Specifically, it means that air can flow from the inside of the housing to the outside, or vice versa. The opening can be covered with a grille or a perforated plate to protect the components inside the housing from mechanical damage or destruction. The phrase "the main fan and at least one auxiliary fan are located on one side of the housing" means that both fans are arranged in parallel planes, in particular in an identical plane, in order to direct the airflow in one direction. In the second aspect, the application provides an RF power module comprising an impedance matching device, as described herein, and an RF power supply. The power module also includes an output terminal, which is connected to the input terminal of the impedance matching device via an RF cable. By means of the above-mentioned technical method, the present invention has the following advantageous effects compared to the prior art: Due to the correct component arrangement and the design of the air channels, heat dissipation far exceeds that of a similar impedance matching device; More efficient electromagnetic isolation is achieved; The creepage distance is increased to successfully prevent the voltage of the output terminal to the housing from rising. The figures schematically describe the development using examples, experimental setups, and simulations. Figures 1-4 show four views of an exemplary embodiment of an impedance matching device. Figure 5 shows a circuit diagram of the impedance matching device. Figures 6-9 show various simulation results for determining the temperature development in the impedance matching device. Figure 10 shows an RF power module with an impedance matching device. An impedance matching device 1 is disclosed, which is used, for example, in the technology field of plasma processing and is used for the function of impedance matching between RF power supply 404 and plasma load 407, as shown in Fig. 10. Figures 1-4 show the same impedance matching device 1 from different viewing angles and partially open or closed. The impedance matching device 1 comprises: a housing 100, an output terminal 230 located at one end of the housing 100 on a side wall, and an input terminal 22 located on another side wall of the housing. Figures 2 and 3 show the first RF capacitor 200 and the second RF capacitor 201. Both capacitors 200 and 201 are designed as variable vacuum capacitors, the capacitance of which can be adjusted by a motor. Figure 3 shows an RF inductor 210. The RF inductor 210 can be designed as a sheet metal part, as shown here. The RF inductor 210 can be designed as a purely air-cooled, i.e., non-liquid-cooled, component, as shown here. The RF inductor 210 can be made of copper. The RF inductor 210 can be connected to the output terminal 230, as shown here. The first RF capacitor 200 and the second RF capacitor 201 can be connected at one end to RF inductor 210, as shown here. This is also shown in a circuit diagram sketch in Fig. 5. One end of the second RF capacitor 201 can be grounded via a grounding inductor 211, as shown here. The output terminal 230 can be arranged on a first side wall of the housing 100, as shown here. The input terminal 22 can also be arranged on a first side wall of the housing 100, as shown here. The side walls of the output terminal 230 and the input terminal 22 can be arranged at an angle of 90° to each other. A mounting rod 25, which can, for example, serve to hold a measuring sensor, can be installed at an angle of 90° relative to the side wall of the housing 100 and, if necessary, relative to the input terminal 22, as shown here. In this design scheme, the RF inductor 210 follows a straight design, which is mainly intended to meet the low inductance requirement of the scheme, and other designs can be chosen using various methods, such as a spiral coil when high inductance is required. As shown in Figs. 2 and 3, in each embodiment of the present application, the end of the first RF capacitor 200 and the second RF capacitor 201 is electrically connected to one end of the RF inductor 210. The central axis of the RF inductor 210 can be perpendicular to the central axis of the first RF capacitor 200, as shown here. The end of the RF inductor 210 that is far from the first RF capacitor 200 can be electrically connected to the output terminal 230 via a conductive connector, as shown here. In the arrangement described here, the components of each embodiment of the present application are primarily used to achieve impedance matching as the first RF capacitor 200, second RF capacitor 201, and RF inductor 210. The first RF capacitor 200 and the second RF capacitor 201 are variable capacitors whose capacitance value can each be controlled within a specific range. The actual variable capacitance range of the two can differ for the same range coverage. For example, the first RF capacitor 200 can be used to control the imaginary part of the impedance, while the second RF capacitor 201 can be used to control the real part of the impedance.In this design scheme, only two variable capacitors are selected as components of the matching path control, primarily for the following reasons: Two variable capacitors are sufficient to meet the requirements of the matching path control. Adding more variable capacitors would only make the control algorithm more complex and the overall size of the matching mechanism larger. The RF inductor 210 is the fundamental component in the matching process, involved in the impedance matching process, and its inductance value is fixed. In Fig. 1 - 3 a main fan 300 and an auxiliary fan 301 are shown on one side of the housing 100 near the first RF capacitor 200. The front projection of the main fan 300 falls on one side of the RF inductor 210. The front projection of the auxiliary fan 301 falls on one side of the first RF capacitor 200. This means that the fans are arranged in such a way that the airflow they generate is directed towards the respective components. Fig. 2 shows a first lateral heat dissipation opening 310. This is also present in the embodiments of Fig. 1, Fig. 3, and Fig. 4. Fig. 2 shows an additional second lateral heat dissipation opening 320. This is also present in the embodiments of Fig. 1, Fig. 3, and Fig. 4. The two lateral heat dissipation openings 310, 320 are arranged opposite the main fan 300 and auxiliary fan 301. The two lateral heat dissipation openings 310, 320 correspond in their dimensions to the dimensions of the two fans. Through the aforementioned method, the application uses the main fan 300 and the heat dissipation opening 310 on the main side as the primary air duct, dissipating heat primarily to the RF inductor 210 and its peripheral components. An auxiliary air duct is formed by using an auxiliary fan 301 and an additional lateral heat dissipation opening 320 to dissipate heat from the first RF capacitor 200 and the second RF capacitor 201, as well as their peripheral components. The central axis of the first RF capacitor 200 and the central axis of the auxiliary fan 301 are located on the same horizontal plane. This further increases the heat dissipation capacity of the auxiliary fan 301 to the first RF capacitor 200. As shown in Fig. 1 and Fig. 4, the top of the housing is equipped with an upper heat dissipation opening 330 at the position of the first RF capacitor 200, the second RF capacitor 201, and the RF inductor 210. This further improves the airflow capacity in the housing 100 by enhancing heat dissipation from the upper area and thus preventing heat buildup. According to simulation tests, the above scheme has a better heat dissipation effect than the traditional layout scheme or the single-fan heat dissipation method, and the comparison results are as follows: Embodiment: The equipment is designed with reference to each embodiment of the present application. The experimental results are shown in Figure 6. 100.14 Pair scale 1: Only a single fan is used, which corresponds to the main fan 300 of the current application, and the component layout corresponds to each version of the current application. The experimental results are shown in Figure 8.110.72 Pair scale 2: Two fans are used, but the auxiliary fan 301 is not in the same plane as the central axis of the first RF capacitor 200. The experimental results are shown in Figure 7.134.75 Pair scale 3. A single fan (corresponding to the main fan 300 of the current application) is used, and the auxiliary fan 301 is not in the same plane as the central axis of the first RF capacitor 200. The experimental results are shown in 9131.25 Horizontal comparison: If the positions of the internal components fully correspond to the layout described in each version of the respective application, the dual fans can reduce the maximum condenser temperature by 200 K, while the single fan can only reduce it to 134 °C. Compared to a single fan, the cooling effect of two fans is significantly more pronounced. Longitudinal comparison: On the one hand, under the same operating conditions of dual fans, the temperature after changing the components by 10 K is higher than that of the components arranged according to the design of the respective application, which can show that the components are arranged better, provided that the dual fans serve as the basis for heat dissipation. On the other hand, in the case of a single fan, the maximum temperature of the capacitors of the two capacitors is closer than that of the sequential arrangement of the components after the change in position, and the maximum temperature of the inductors after the change in position is higher than that of the sequential arrangement, which may indicate that the sequential arrangement of the components is better when the single fan serves as the basis for heat dissipation. In combination with the results of the aforementioned horizontal and vertical comparisons, it can be concluded that two fans and the sequential arrangement of the components are the best design solution in all four cases. As shown in Figures 2 and 3, a partition 110 is arranged in the housing 100. The partition 110 serves to divide the housing space into an RF compartment and a low-voltage compartment. The low-voltage compartment is for accommodating a low-voltage component, and the RF compartment is for housing the RF circuit components, including the RF capacitors 200, 201, and the RF inductor 210. The interior of the housing 100 is divided by the partition 110, thereby effectively preventing the negative impact of electromagnetic interference on the component. As shown in Fig. 2 and Fig. 4, a groove 231 is provided on the outer surface of the housing 100, surrounding the output terminal 230. By adjusting the groove 231, the creepage distance can be increased to further prevent the voltage of the output terminal from rising on the housing, thereby improving the operational stability of the impedance matching device. As shown in Figs. 3 and 4, the housing 100 has a lower plate 101, a side plate 102, and an upper plate 103. The lower plate 101 can be arranged in a plane, as shown here. The side plate 102 can be rigidly connected by three flat plates, as shown here. As shown here, the mounting angle of the plates can each be 90 degrees. As shown here, half of the plates can enclose the lower plate 101. The lower plate 101 can also be referred to as the base plate. The output port 230 is located on a flat plate, preferably in the center of the side plate 102. The upper plate 103 can be rigidly connected to a flat plate, as shown here. The upper plate 103 can be identical to the lower plate 101, as shown here. The upper plate 103 can be attached to another flat plate at a 90-degree angle, as shown here. The upper plate 103 and the side plate(s) 102 can together enclose the four sides of the lower plate 101, as shown here. The side plate 102 and the base plate 101 can be rigidly connected to each other, as shown here.The upper plate 103, the side plate 102, and the lower plate 101 can be detachably connected, as shown here. Among other methods, the fixed connection can be bolted or welded, and the detachable connection can be made using bolts, buckles, or other joining techniques. The removable connection between the upper plate 103 and the side plate 102 as well as the lower plate 101 allows the upper plate 103 to be directly disassembled to facilitate the construction process when components need to be overhauled and replaced, thus improving convenience. The described RF capacitance is the first RF capacitor 200 or the second RF capacitor. Fig. 10 shows an RF power module 400 with a plasma processing unit 407. The plasma processing unit 407 can be designed as an inductively excitable plasma processing unit, as shown here. The RF power module 400 comprises: an RF power supply 404, an RF cable 402, and an impedance matching device 1 as described herein. The plasma processing device 407 can be directly connected to the output terminal 230 of the impedance matching device 1, as shown herein. The RF power supply 400 can, as shown herein, include a power supply output terminal 401, and the power supply output terminal 401 can be connected to the input terminal 22 of the impedance matching device 1 via the RF cable 402, as shown herein. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature CN 217470562U

[0004]

Claims

Impedance matching device (1) comprising a housing (100), an input terminal (22) and an output terminal (230), wherein a first RF capacitor (200), a second RF capacitor (201) and an RF inductor (210) are arranged in the housing (100), wherein a main fan (300) and an auxiliary fan (301) are arranged on a first side of the housing (100) such that a main air duct and an auxiliary air duct are formed in the housing (100) during operation; wherein an upper heat dissipation opening (330) is arranged in a top of the housing (100), and a side heat dissipation opening (310) is arranged on a side of the housing (100) opposite the main fan (300);wherein the main fan (300), the side heat dissipation opening (310) and the upper heat dissipation opening (330) are arranged such that they together form part of the main air duct in the housing and the main air duct passes successively by the RF inductor (210) and the output terminal (230). Impedance matching device according to claim 1, wherein a separating surface (110) is arranged in the housing (100), and the separating surface (110) serves to divide the housing space into an RF and a low voltage space, wherein low voltage components are arranged in the low voltage space and RF circuit components, including the RF capacitors (200, 201) and the RF inductor (210), are arranged in the RF space. Impedance matching device according to one of the preceding claims, wherein the central axis of the first RF capacitor (200) and the central axis of the auxiliary fan (301) are located on the same horizontal plane. The impedance matching device according to one of the preceding claims, wherein the first RF capacitor (200) corresponds to at least a part of the projection of the auxiliary fan (301). Impedance matching device according to one of the preceding claims, wherein the RF capacitors (200, 201) and the lateral heat dissipation opening (310) are arranged such that during operation an auxiliary air duct is formed between the auxiliary fan (301) and the lateral heat dissipation opening (310) and the auxiliary air duct passes by the first capacitor (200), in particular by both RF capacitors (200, 201). Impedance matching device according to one of the preceding claims, wherein the output terminal (230) is arranged at one end of the housing and has a groove (231) in the outer surface of the housing around the output terminal. Impedance matching device according to one of the preceding claims, wherein the housing (100) has a lower plate (101), a side plate (102) and an upper plate (103), wherein the lower plate (101) is arranged in a planar position, the side plate (102) is rigidly connected by three flat plates such that the angle is 90 degrees, and the upper plate (103) is rigidly connected by a flat plate identical to the lower plate and another flat plate in the state of an angle. Impedance matching device according to one of the preceding claims, wherein a first end of the first RF capacitor (200) is electrically connected to the input terminal (22). Impedance matching device according to one of the preceding claims, wherein a second end of the first RF capacitor (200) is electrically connected to the RF inductor (210). Impedance matching device according to one of the preceding claims, wherein a first end of the second RF capacitor (201) is electrically connected to the input terminal (23). Impedance matching device according to one of the preceding claims, wherein a second end of the second RF capacitor (201) is electrically connected to a grounding inductor (211). Impedance matching device according to one of the preceding claims, wherein a grounding inductor (211) is connected to ground. RF power module (400) comprising an RF power supply (404), an RF cable (402) and an impedance matching device (1) according to one of the preceding claims, wherein RF power supply (400) comprises an output terminal (401) and the output terminal (401) is connected to the input terminal (22) of the impedance matching device (1) via an RF cable.

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