Power converter unit, plasma processing apparatus and method of controlling a plurality of plasma processes
By converting electrical input power into bipolar output power and controlling it independently using a control device, the problem of high installation costs in plasma processing equipment is solved, achieving efficient power distribution and flexible operation of the plasma processing chamber.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TRUMPF HUETTINGER SP ZOO
- Filing Date
- 2018-04-27
- Publication Date
- 2026-06-05
AI Technical Summary
In existing plasma processing equipment, the excessive installed power from multiple independent power sources leads to high installation costs.
A power converter unit is used to convert electrical input power into bipolar output power, which is then delivered to multiple plasma processing chambers via a control device. The operation of each output port is controlled by control parameters such as power, voltage, current, excitation frequency, and threshold, thereby realizing the function of a virtual power supply.
This reduces the installation cost of the equipment while enabling efficient power distribution and independent control of multiple plasma processing chambers, thus improving the flexibility and efficiency of the equipment.
Smart Images
Figure CN114583981B_ABST
Abstract
Description
[0001] This application is a divisional application of the invention patent application filed on April 27, 2018, with application number 201880040374.2 (PCT / EP2018 / 060939) and entitled "Power converter unit, plasma processing device and method for controlling multiple plasma processes". Technical Field
[0002] This invention relates to a power converter unit, a plasma processing device, and a method for controlling multiple plasma processes. Background Technology
[0003] Many plasma processing devices employ multiple independent plasma processing chambers, in which plasma processing is performed in parallel. Such plasma processing devices are known from US 2014 / 0357064 A1, US 2006 / 0156979 A1, US 2005 / 0034667 A1, US 7,396,759 B1, US 6,756,318 B2, US 6,495,392 B2, and US 6,271,053 B1. For this purpose, these devices employ multiple independent power supplies connected to the individual chambers. In many cases, the power delivered to all chambers is always less than the sum of the rated power installed on the machine through all the independent power supplies. This excess installed power leads to high installation costs. Summary of the Invention
[0004] One objective of this invention is to reduce excess costs.
[0005] The stated objective is achieved by the power converter unit according to the invention, by the plasma processing apparatus according to the invention, and by the method according to the invention. Other independent or preferred aspects of the invention are covered by the dependent claims and the description.
[0006] The power converter unit is capable of converting electrical input power into bipolar output power and delivering the output power to at least two independent plasma processing chambers, the unit comprising:
[0007] - One power input port for connecting to the power grid.
[0008] - At least two, preferably more than two, power output ports, each for connection to a corresponding one in the plasma processing chamber.
[0009] - A control device configured to control the unit to deliver bipolar output power to a power output port using control parameters of at least one of the following: power, voltage, current, excitation frequency, and a threshold for protection measures, such that at least one of the control parameters at the first power output port differs from the corresponding control parameters at different power output ports. Thus, several of these can be replaced by a single power converter unit with a given maximum power capacity.
[0010] In this disclosure, utilizing bipolar output power refers to utilizing the output power of alternating current, wherein the current changes its direction at a frequency (excitation frequency) that can excite plasma processes.
[0011] The control parameter can be a measured value or a set value of the parameter.
[0012] The measured and set values can be absolute values such as root mean square (rms), actual values, effective values, or limit values such as maximum or minimum values.
[0013] The input power can be electrical power supplied from the AC power grid. It can also be DC power line power.
[0014] When the power unit is in use, the control device may include a microcontroller with software programs running thereon.
[0015] The control device may have multiple interfaces, such as data connections to external components, monitors, and keyboards, which can be wired or wireless.
[0016] The control device may have a computing section and a memory section. The memory section may be divided for various purposes, such as monitor memory, RAM, data memory, and program memory.
[0017] The threshold can be a value used to detect ignition or breakdown of the plasma. Different values can be specified for each output port, and it can vary over time.
[0018] The bipolar output power can be greater than 1kW, preferably greater than 10kW.
[0019] The frequency of the bipolar output power can be greater than 1 kHz, preferably greater than 10 kHz, and preferably greater than 50 kHz.
[0020] On the other hand, the power converter unit may include a first power converter stage configured to convert input power into intermediate power, preferably into DC link power.
[0021] On the other hand, the power converter unit may include at least one additional power converter stage configured to convert intermediate power from the first power converter stage into bipolar output power.
[0022] On the other hand, the power converter unit may include at least two additional power converter stages configured to convert intermediate power from the first power converter stage into multiple bipolar output power signals and direct these power signals to the power output port.
[0023] On the other hand, the power converter unit may include a switching device between the power converter stage and the output port.
[0024] On the other hand, the switching device is controlled by a control device. A switching device for switching between electrodes in only one plasma chamber is described in US 6,620,299 B1.
[0025] On the other hand, the control device can be configured to control the power converter stage and / or switching device such that, in use, the unit delivers a first output power signal at the first output power port for a first time frame at a first time, and delivers a second power signal at the second output power port for a second time frame at a second time, wherein the first time is different from the second time and / or the first time frame is different from the second time frame.
[0026] On the other hand, the switching device is configured to direct the current in two opposite directions.
[0027] On the other hand, the control device can be configured to activate the switching device from the closed state to the open state only when the absolute value of the current through the switch is less than one ampere, preferably zero.
[0028] On the other hand, the control device can be configured to activate the switching device from the open state to the closed state only when the absolute value of the voltage along the open switch is less than 20 volts, preferably zero.
[0029] On the other hand, at least one of the power converter stages includes a bridge circuit, preferably a full-bridge circuit.
[0030] A bridge circuit can be a rectifier bridge circuit capable of rectifying AC power.
[0031] A bridge circuit can be a bipolar output power generating switching bridge circuit.
[0032] On the other hand, the power converter unit may include a cabinet that surrounds all other parts of the unit.
[0033] On the other hand, the input ports can be directly connected to the cabinet.
[0034] On the other hand, the output ports can be directly connected to the rack.
[0035] On the other hand, plasma processing equipment may include:
[0036] - Two, preferably more than two, plasma processing chambers.
[0037] - An electric power converter unit as described above.
[0038] Each plasma processing chamber can be connected to a corresponding power output port of the power converter unit.
[0039] On the other hand, at least one, preferably all, of the plasma processing chambers can be configured to handle plasma vapor deposition (PVD) processes in use.
[0040] At least one, preferably all, of the plasma processing chambers can be configured to handle plasma-enhanced chemical vapor deposition (PECVD) processes in use.
[0041] At least one, preferably all, of the plasma processing chambers can be configured to handle atomic layer deposition (ALD) processes in use.
[0042] At least one, preferably all, of the plasma processing chambers can be configured to handle plasma etching processes in use.
[0043] The objective is also achieved by a method that utilizes a control device to control multiple plasma processes in multiple plasma processing chambers by converting electrical input power into bipolar output power and delivering that output power to the plasma processing chamber. The control device uses control parameters of at least one of the following: power, voltage, current, excitation frequency, and threshold values for protection measures. It controls a power converter unit to deliver bipolar output power to a power output port by establishing a virtual power supply for each output port. Each virtual power supply, along with all fixed and time-varying parameters associated with the operation of each individual output port and a separate complete set of internal states, is stored in the control device.
[0044] In another aspect of the method, the control device controls the power converter unit such that at least one of the control parameters at the first plasma chamber is different from the corresponding control parameters at different plasma chambers.
[0045] In another aspect of the method, the desired value for the entire group can be obtained via an interface connection, preferably from a controller outside the power converter unit, wherein the external controller also controls the plasma process in the plasma chamber.
[0046] In another aspect of the method, the calculation may include always calculating the maximum expected power and comparing it with the maximum power rating of the power converter unit.
[0047] In another aspect of the method, an error message can be given if the calculated result is that there is no way to deliver the expected value to each output port.
[0048] In another aspect of the method, if the result of the calculation is not possible to deliver the expected value to each output port, one or more options can be given to change the process with a new set of expected values.
[0049] In another aspect of the method, the control device can control the power converter unit such that at least one of the control parameters at the first plasma chamber is different from the corresponding control parameters at different plasma chambers.
[0050] The plasma processes in different plasma chambers can be different or the same. They can be the same but in different states, meaning, for example, that the plasma process in the first plasma chamber is in the PECVD state, while the plasma process in another plasma chamber is in the initial cleaning state, and the same PECVD state subsequently operates while the plasma process in the first plasma chamber may be in the etching state. All these processes can be performed simultaneously, in a time-multiplexed manner, or in combination. Attached Figure Description
[0051] The accompanying drawings schematically illustrate some examples of the invention, which are described in more detail below. The drawings show:
[0052] Figure 1 This is a first plasma processing device with a power converter unit according to the present invention;
[0053] Figure 2 This is a second plasma processing device with a second power converter unit according to the present invention;
[0054] Figure 3 This is a timing diagram of the output power at the first output power port;
[0055] Figure 4 This is a timing diagram of the output power at the second output power port;
[0056] Figure 5It is a rectifier bridge circuit;
[0057] Figure 6 It is a bipolar power conversion bridge;
[0058] Figure 7 This is the first embodiment of the switching device;
[0059] Figure 8 This is a second embodiment of the switching device. Detailed Implementation
[0060] exist Figure 1 The image shows a first plasma processing device 19 having a first power converter unit 1. The plasma processing device 19 includes plasma processing chambers 9a, 9b, ..., 9n. Each plasma processing chamber is connected to a power output port 3a, 3b, ..., 3n.
[0061] The power converter unit 1 includes a power input port 2 for connecting to the power transmission network 7.
[0062] The power converter unit 1 also includes a first power converter stage 5, which is configured to convert the input power at the input power port 2 into intermediate power, preferably into DC link power 12. Furthermore, a plurality of first power converter stages 5 configured to convert the input power at the input power port 2 into intermediate power, preferably into DC link power 12, may be part of the power converter unit 1 and are preferably connected in parallel.
[0063] The power converter unit 1 also includes another power converter stage 6 connected downstream to the first power converter stage 5, which is configured to convert intermediate power from the first power converter stage into bipolar output power.
[0064] Between power converter stage 5 and another power converter stage 6, energy storage elements such as inductors or capacitors can be implemented to smooth the current or voltage.
[0065] The power converter unit 1 also includes multiple switching devices 8a, 8b, ..., 8n between the power converter stage 6 and the output ports 3a, 3b, ..., 3n.
[0066] The power converter unit 1 further includes a control device 4 configured to control the power converter unit 1 to deliver bipolar output power to the power output ports 3a, 3b, ... 3n using control parameters of at least one of the following: power, voltage, current, excitation frequency, and threshold for protection measures, such that at least one of the control parameters at the first power output port 3a is different from the corresponding control parameters at the different power output ports 3b, ... 3n.
[0067] In this example, control device 4 has connections to power converter stages 5, 6 and switching devices 8a, 8b, ..., 8n. Some of these connections can be optional, such as the connection to power converter stage 5. Control device 4 can be configured to activate switching devices 8a, 8b, ..., 8n from a closed state to an open state only when the absolute value of the current through the switch is less than 1 ampere, preferably zero. The advantage of this is that switching devices that do not need to be designed to switch higher currents can be used. This makes the unit even cheaper.
[0068] The control device 4 can also be configured to activate the switching devices 8a, 8b, ..., 8n from the open state to the closed state only when the absolute value of the voltage along the open switch is less than 20 volts, preferably zero. The advantage of this is that switching devices that do not need to be designed to switch higher voltages can be used. This makes the unit even cheaper.
[0069] In the example, such as Figure 7 and 8 As shown, bipolar transistors 81, 82, 91, and 92 are used. These bipolar transistors are much cheaper than MOSFETs. Bipolar transistors 81, 82, 91, and 92 can be IGBTs, a type of low-cost transistor used to drive high current with low energy loss. Since expensive cooling devices are not required, this makes cell 1 even cheaper.
[0070] exist Figure 7 and 8 In the middle, additional diodes 83, 84, 93, and 94 are connected to direct the current in the desired direction and block the current in the unwanted direction.
[0071] The first power converter stage 5 may include a rectifier circuit, preferably as follows: Figure 5 The bridge rectifier circuit 50 is shown. Four rectifier diodes 52, 53, 54, and 55 are connected in the bridge circuit to rectify the AC power rectified from the first port 51 to the second port 56. At least one of the following can be additionally connected at the first port 51: a filter, an overvoltage protection circuit, or an overcurrent protection circuit. The filter may include one or more energy storage elements, such as capacitors or inductors.
[0072] The second power converter stage 6 may include a switching bridge, preferably as follows: Figure 6The full-bridge switching bridge 60 is shown. This full-bridge switching bridge 60 includes four switching devices 62, 63, 64, and 65. These switching devices can be transistors, bipolar transistors, IGBTs, and most preferably MOSFETs. A filter circuit including one or more energy storage elements such as capacitor 61 and / or inductors 66 and 67 can be located at the input of the second power converter stage 6. The full-bridge switching bridge 60 may also include diodes as shown.
[0073] The power converter unit 1 may include a cabinet 10 that surrounds all other parts of the unit 1. It may be metallic, thus providing good protection against electromagnetic interference. Input port 2 can be directly connected to cabinet 10. Output ports 3a, 3b, ..., 3n can also be directly connected to cabinet 10.
[0074] In a power converter unit 1, the current carrying capacity of all switching devices 8a, 8b, ..., 8n together can exceed the maximum power delivery capability of all power converter stages 5 together.
[0075] exist Figure 2 The image shows a second plasma processing device 19' having a second power converter unit 1'. The second power converter unit 1' is as follows: Figure 1 The replacement of the first power converter unit 1 shown. All with Figure 1 Identical components have the same reference numerals. For example... Figure 2 As shown, the power converter unit 1' includes multiple power converter stages 6a, 6b, ..., 6n replacing the switching devices 8a, 8b, ..., 8n. These stages are configured to convert the intermediate power 12 of the first power converter stage 5 into multiple bipolar output power signals and direct these power signals to power output ports 3a, 3b, ..., 3n. All power converter stages 6a, 6b, ..., 6n can be controlled by the control device 4. All power converter stages 6a, 6b, ..., 6n may include, for example... Figure 6 The full-bridge 60 and filter elements 61, 66, and 67 are shown.
[0076] Measurement sensors used to detect voltage, current, frequency, or power can be connected to output ports 3a, 3b, ..., 3n (not shown).
[0077] Additionally, a plurality of first power converter stages 5 configured to convert the input power at the input power port 2 into intermediate power, preferably into DC link power 12, may be part of the power converter unit 1 and are preferably connected in parallel.
[0078] Figure 3A timing diagram of the output power at the first output power port 3a is shown. Axis t is the time axis, while axis S30 can be, for example, a voltage, current, or power axis. Since axis S30 is used for the actual values of these parameters, axis S31 is used for the effective values of these parameters. Figure 3 In the first figure with the S30 axis, the bipolar signal is shown as two signal sequences 31 and 32. Signal sequence 31 has an excitation frequency with a period of 2 / 11 of the time frame from time point T31 to time point T32. Signal sequence 32 has an excitation frequency with a period of 2 / 11 of the time frame from time point T33 to time point T34. In this example, these frequencies are the same, but they could be different. Figure 3 In the second figure with axis S31, the effective values of the two signal sequences 31 and 32 are shown as two signal sequences 33 and 34. Two threshold lines 35 and 36 are also shown in this figure. These thresholds can be used to detect plasma breakdown, such as electric arcs or plasma ignition, when the effective value of one of the parameters—power, voltage, or current—exceeds these thresholds.
[0079] In a power converter unit 1', the current carrying capacity of all power converter stages 6a, 6b, ..., 6n together can be higher than the maximum power delivery capability of all power converter stages 5 together.
[0080] Figure 4 A timing diagram of the output power at different output power ports 3b, ..., 3n is shown. Axis t is the time axis, while axis S40 can be, for example, a voltage, current, or power axis. Since axis S40 is used for the actual values of these parameters, axis S41 is used for the effective values of these parameters. Figure 4 In the first diagram with the S40 axis, the bipolar signal is shown as two signal sequences 41 and 42. Signal sequence 41 has an excitation frequency with a period of 1 / 7 of the time frame from the start of time point T41 to the end of time point T42. At time point T43, the second pulse 44 begins, and its end is not visible in this diagram. As can be seen from this example, the frequencies of signals 31 and 32 are different from the frequencies of signals 41 and 42, and the frequencies of signals 41 and 42 are higher than the frequencies of signals 31 and 32.
[0081] As a supplement or alternative to the excitation frequency, the power, voltage, current, and threshold values for protection measures can also differ between two different output ports 3a, 3b, ..., 3n or between two different plasma chambers 9a, 9b, ..., 9n.
[0082] The figure also shows two threshold lines, 45 and 46. These thresholds can be used to detect plasma breakdown, such as electric arcs or plasma ignition, when the effective value of one of the parameters, power, voltage, or current, exceeds such thresholds.
[0083] The present invention operates as follows: A control device 4 controls multiple plasma processes in multiple plasma processing chambers 9a, 9b, ..., 9n by converting electrical input power into bipolar output power as shown in signal sequences 31, 32, 41, 42, and delivering this output power to plasma processing chambers 9a, 9b, ..., 9n. The control device 4 uses control parameters of at least one of the following to control the power converter unit 1 to deliver the bipolar output power to the power output ports 3a, 3b, ..., 3n: power, voltage, current, excitation frequency, and a threshold value for protection measures.
[0084] Therefore, the control device 4 can control the power converter stages 6, 6a, 6b, ..., 6n and / or the switching devices 8a, 8b, ..., 8n, so that in use, the unit 1 transmits a first output power signal at the first output power port 3a for a first time frame T31-T32 at a first time T31, and transmits a second power signal at the second output power ports 3b, ..., 3n for a second time frame T41-T42 at a second time T41, wherein the first time T31, T41 is different from the second time T32, T42 and / or the first time frame T31-T32 is different from the second time frame T41-T42.
[0085] Control device 4 includes virtual power supplies 24a, 24b, ..., 24n. For Figure 1 The power converter unit 19, wherein the output power from a central converter stage 5, 6 is routed to different output ports 3a, 3b, ..., 3n. Furthermore, the plasma processes driven from the different output ports 3a, 3b, ..., 3n will, in general, apply different operating points in terms of power, impedance, etc. By using virtual power supplies 24a, 24b, ..., 24n, a complete set of all fixed and time-varying parameters and internal states associated with the operation of each individual output port 3a, 3b, ..., 3n is stored in the control device 4. For example, this means that when the active output port 3a switches from 3a to 3b, the control device 4 restores from memory the regulation state that existed when the output power last switched away from output 3b. This also means, for example, for a power supply with N outputs, there will be N sets of individual arc management parameters, or N sets of pulse frequency and duty cycle settings controlled and synchronized by the sequence controller 14.
[0086] The sequence controller 14 is part of the control device 4. Its algorithm determines each request made to the power converter unit 1 to deliver output power to any of its output ports, or determines a request to change one or more parameters of the output port, regardless of whether the request is within the possible range of operation. For example, Figure 3 and 4 The process shown illustrates the power being delivered to output ports 3a, 3b, ..., 3n, where different output ports 3a, 3b, ..., 3n are driven with different power levels, different pulse duty cycles, and different pulse frequencies. The sequence controller ensures that:
[0087] • Pulse frequencies are integer multiples of each other to avoid pulse overlap (for example, for example...). Figure 2 The plasma device shown in Figure 19')
[0088] • For pulse overlap, the requested total output power and current shall not exceed the maximum possible values (for example, for pulse overlap). Figure 2 The plasma device shown in Figure 19')
[0089] • If the maximum possible value is exceeded within a finite period of time in the loop, find a pattern without this constraint if possible (for example, Figure 2 The plasma device shown in Figure 19')
[0090] • The sum of the pulse on-time and the switching time between outputs is less than the cycle time of the lowest frequency pulse (for example, Figure 1 Plasma equipment 19)
[0091] • Activate the newly requested output pulse pattern on a specific output at the appropriate time to adapt to the pre-existing activated pulse patterns on other outputs (for example, Figure 1 Plasma equipment 19)
[0092] • Not exceeding total average power and current limits
[0093] • If the requested sequence exceeds the possible range, issue a warning to the user.
[0094] • Recommend possible modification sequences to the user.
Claims
1. A power converter unit (1, 1') capable of converting electrical input power into bipolar output power and delivering the output power to at least two independent plasma processing chambers (9a, 9b, ..., 9n), the power converter unit (1, 1') comprising: - A power input port (2) for connecting to the power transmission network (7). - At least two power output ports (3a, 3b, ..., 3n), each power output port (3a, 3b, ..., 3n) is used to connect to a corresponding one in the plasma processing chambers (9a, 9b, ..., 9n). - A control device (4) configured to control the power converter unit (1, 1') using at least one of the following control parameters to deliver bipolar output power to the power output ports (3a, 3b, ..., 3n): power, voltage, current, excitation frequency, or a threshold for protection measures. The control device (4) includes virtual power supplies (24a, 24b, ..., 24n) for each power output port (3a, 3b, ..., 3n). Each virtual power supply (24a, 24b, ..., 24n) contains an independent complete set of all fixed and time-varying parameters associated with the operation of each individual power output port (3a, 3b, ..., 3n) as well as internal states. The control device (4) has connections to the power converter stages (5, 6, 6a, 6b, ..., 6n) and the switching devices (8a, 8b, ..., 8n). The control device (4) is configured to control the power converter stages (5, 6, 6a, 6b, ..., 6n) and / or the switching devices (8a, 8b, ..., 8n) such that, in use, the power converter units (1, 1') transmit a first output power signal at the first output power port (3a) for a first time frame (T31-T32) at a first time (T31), and transmit a second power signal at the second output power port (3b, ... 3n) for a second time frame (T41-T42) at a second time (T41), wherein the first time (T31) is different from the second time (T41) and / or the first time frame (T31-T32) is different from the second time frame (T41-T42).
2. The power converter unit (1, 1') according to claim 1, wherein, The power converter unit (1, 1') includes a first power converter stage (5) configured to convert input power into intermediate power.
3. The power converter unit (1, 1') according to claim 2, wherein, The power converter unit (1, 1') includes at least one additional power converter stage (6, 6a, 6b, ..., 6n) configured to convert intermediate power from the first power converter stage (5) into bipolar output power.
4. The power converter unit (1') according to claim 2 or 3, wherein, The power converter unit (1') includes at least two additional power converter stages (6a, 6b, ..., 6n) configured to convert intermediate power from the first power converter stage (5) into a plurality of bipolar output power signals and direct these power signals to power output ports (3a, 3b, ..., 3n).
5. The power converter unit (1, 1') according to any one of claims 1-3, wherein, The power converter unit (1, 1') includes a switching device (8a, 8b, ..., 8n) between the power converter stage (5, 6, 6a, 6b, ..., 6n) and the output port (3a, 3b, ..., 3n).
6. The power converter unit (1, 1') according to any one of claims 1-3, wherein, The switching devices (8a, 8b, ..., 8n) are controlled by the control device (4).
7. The power converter unit (1, 1') according to any one of claims 1-3, wherein, The control device (4) is configured to activate the switching device (8a, 8b, ..., 8n) from the closed state to the open state only when the absolute value of the current through the switching device (8a, 8b, ..., 8n) is less than one ampere.
8. The power converter unit (1, 1') according to any one of claims 1-3, wherein, The control device (4) is configured to activate the switching devices (8a, 8b, ..., 8n) from the open state to the closed state only when the absolute value of the voltage along the open switching devices (8a, 8b, ..., 8n) is less than 20 volts.
9. The power converter unit (1, 1') according to any one of claims 1-3, wherein, At least one of the power converter stages (5, 6, 6a, 6b, ..., 6n) includes a bridge circuit.
10. The power converter unit (1, 1') according to any one of claims 1-3, wherein, The power converter unit includes a cabinet (10) surrounding all other parts of the power converter unit (1, 1'), and wherein the power input port (2) is directly connected to the cabinet (10), and wherein the power output ports (3a, 3b, ..., 3n) are directly connected to the cabinet (10).
11. The power converter unit (1, 1') according to claim 2, wherein, The first power converter stage (5) is configured to convert input power into DC link power.
12. The power converter unit (1, 1') according to claim 7, wherein, The control device (4) is configured to activate the switching device (8a, 8b, ..., 8n) from the closed state to the open state only when the absolute value of the current through the switching device (8a, 8b, ..., 8n) is zero.
13. The power converter unit (1, 1') according to claim 8, wherein, The control device (4) is configured to activate the switching device (8a, 8b, ..., 8n) from the open state to the closed state only when the absolute value of the voltage along the open switching device (8a, 8b, ..., 8n) is zero.
14. The power converter unit (1, 1') according to claim 9, wherein, At least one of the power converter stages (5, 6, 6a, 6b, ..., 6n) is a full-bridge circuit.
15. A plasma processing apparatus (19, 19'), comprising: - Two or more plasma processing chambers (9a, 9b, ..., 9n) - A power converter unit (1, 1') as described in any of the preceding claims, and - Each plasma processing chamber (9a, 9b, ..., 9n) is connected to a corresponding one of the power output ports (3a, 3b, ..., 3n) of the power converter unit (1, 1') and a controller (17) outside the power converter unit (1, 1').
16. The plasma processing apparatus (19, 19') according to claim 15, wherein, At least one of the plasma processing chambers is configured to handle PECVD processes in use.
17. The plasma processing apparatus (19, 19') according to claim 15, wherein, The two plasma processing chambers in the plasma processing chamber are configured to handle PECVD processes in use.
18. The plasma processing apparatus (19, 19') according to claim 15, wherein, All plasma processing chambers in the plasma processing room are configured to handle PECVD processes in use.
19. A method for controlling multiple plasma processes in multiple plasma processing chambers (9a, 9b, ..., 9n) by using a control device (4) to convert electrical input power into bipolar output power and deliver the output power to plasma processing chambers (9a, 9b, ..., 9n), wherein, The control device (4) uses control parameters of at least one of power, voltage, current, excitation frequency, and threshold values for protection measures to control the power converter unit (1, 1') by establishing virtual power supplies (24a, 24b, ..., 24n) for each power output port (3a, 3b, ..., 3n) to deliver bipolar output power to the power output ports (3a, 3b, ..., 3n). Each virtual power supply (24a, 24b, ..., 24n) contains a separate complete set of all fixed and time-varying parameters associated with the operation of each individual power output port (3a, 3b, ..., 3n) as well as internal states. The control device (4) has connections to the power converter stages (5, 6, 6a, 6b, ..., 6n) and the switching devices (8a, 8b, ..., 8n). The control device (4) is configured to control the power converter stages (5, 6, 6a, 6b, ..., 6n) and / or the switching devices (8a, 8b, ..., 8n) such that, in use, the power converter units (1, 1') transmit a first output power signal at the first output power port (3a) for a first time frame (T31-T32) at a first time (T31), and transmit a second power signal at the second output power port (3b, ... 3n) for a second time frame (T41-T42) at a second time (T41), wherein the first time (T31) is different from the second time (T41) and / or the first time frame (T31-T32) is different from the second time frame (T41-T42).