Plasma generator, plasma processing equipment and power pulse supply method

Abstract

The present invention relates to a plasma generator, a plasma processing device and a method for supplying power pulses. The plasma generator comprises: a control unit configured to obtain and evaluate process data related to processes in at least two process chambers; a controllable power supply unit having an output, configured to output direct current at its output in response to a control signal of the control unit; and a switching unit having at least two switching unit outputs for each connection to one of the process chambers. The switching unit is configured to form an alternating current as an output signal, and output the output signal to the switching unit output in response to the control signal. The control unit is configured to coordinate the power requirements of the process chambers and drive the power supply unit and the switching unit so that the power corresponding to the power requirements is provided as a pulse in a time period at each switching unit output connected to the process chamber, and the pulses of each process chamber are staggered in time so that the process chambers can work synchronously.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880023582.1 (application date: March 29, 2018, invention name: plasma generator, plasma processing equipment and power pulse supply method). Technical Field

[0002] The present invention relates to a plasma generator for pulse supplying electric power having a frequency of at least 40 KHz, a plasma processing apparatus, and a method for pulse supplying electric power having a frequency of at least 40 KHz. Background Art

[0003] Various fields of application are known in the prior art in which electrical power with a frequency of at least 40 kHz is supplied to ignite a plasma from a gas excitation and to maintain the plasma for a specific process. Examples are plasma-assisted gas deposition in the field of semiconductor technology or the photovoltaic industry.

[0004] Here, for example, the wafers are loaded into a so-called "wafer boat", which is partially composed of conductive plates, and are transported to a corresponding process chamber. In this case, power with a frequency of at least 40 kHz is applied to the wafer boat in order to generate a plasma from a suitable gas between the plates and between the wafers accommodated on the plates. Such a plasma processing device is disclosed in DE 10 2015 004 419 A1 of the applicant of the present case.

[0005] Such plasma processing equipment is usually composed of a single process chamber, and this process chamber corresponds to a single plasma generator. In the case of an adjacent arrangement of several process chambers, although the gas cabinet and other peripheral equipment are partially used in common, each process chamber has a single plasma generator so far. Such a plasma generator usually has a controllable power supply unit including an output, which is configured to output a direct current with a predetermined voltage and / or intensity at its output, and has a converter, which is configured to form an alternating current with a predetermined frequency of at least 40KH from the direct current on the input as an output signal, and apply this output signal to the connected process chamber. In this case, this power supply unit and this converter are usually controlled by a controller, and this controller determines the power required by the process chamber and generates a corresponding control signal. An arc suppression unit is also usually provided, which obtains current process data about the process in the process chamber and current data of the power supply unit and / or the switch in a suitable manner and performs real-time evaluation to detect an arc or an impending arc, wherein the arc suppression unit is connected to the power supply unit and / or the switch and controls these elements in a manner that responds to the detection of an arc or an impending arc, as the case may be, so that an arc in the process chamber is avoided or quickly suppressed.

[0006] During the process, power is usually provided periodically as pulses by the corresponding plasma generator, wherein a duty cycle (the quotient of the pulse duration and the period duration) of less than 0.1 is usually set over a relatively long period of time. Such pulsed operation of the plasma in the process chamber has proven to be particularly advantageous. Thus, over a wide range of the process, 90% of the available continuous power of the plasma generator is not used. There are also processes with a significantly reduced duty cycle, as well as processes or process sections with a higher duty cycle. Summary of the invention

[0007] Therefore, the object of the present invention is to provide electric power more efficiently. The solution of the present invention to achieve the above object is a plasma generator according to claim 1, a plasma processing device according to claim 14, and a method according to claim 17. Other technical solutions of the present invention mainly refer to the dependent claims.

[0008] In particular, a plasma generator for pulsed supply of electric power having a frequency of at least 40 kHz to at least two process chambers is proposed, wherein the plasma generator has the following components: a control unit configured to obtain and evaluate process data about processes in the at least two process chambers; a controllable power supply unit having an output, configured to output a direct current having a predetermined voltage and / or intensity at its output in response to a control signal of the control unit; and a switching unit having a first input connected to the output of the power supply unit and having at least two switching unit outputs for each connection to one of the at least two process chambers;

[0009] The switching unit is configured to generate an alternating current with a predetermined frequency of at least 40 kHz from the direct current on the input as an output signal, and to selectively output the output signal as a pulse to one of the switching unit outputs within a predetermined pulse duration in response to a control signal from the control unit; wherein the control unit is configured to coordinate the power requirements of at least two process chambers, and drive the power supply unit and the switching unit so that power corresponding to the power requirement is provided as a pulse within a time period at each switching unit output connected to the process chamber, wherein the pulses are staggered in time so that the process chambers can operate synchronously.

[0010] Such a plasma generator realizes a coordinated pulse power supply to a plurality of process chambers, thereby improving the efficiency of the plasma generator in general. The acquisition cost of a multi-chamber plasma processing unit can be greatly reduced because the number of the plasma generators is halved or further reduced. In particular, for process chambers implementing similar processes, the process chambers can be efficiently coordinated.

[0011] In one embodiment, the control unit has a number of controllers corresponding to the number of process units to be connected to the switching unit, wherein each controller is configured to obtain process data about the process in the corresponding process chamber, wherein each controller is connected to the power supply unit and / or the switching unit in order to control these elements in response to the received process data. In this way, a good and reliable regulation of the processes can be achieved. The plasma generator preferably also has at least one arc suppression unit, which is configured to obtain and evaluate in real time current process data about the processes in the at least two process chambers and current data of the power supply unit and / or the switching unit in order to detect an arc or an impending arc, wherein the arc suppression unit is connected to the power supply unit and / or the switching unit in order to control these elements in response to the detection of an arc or an impending arc, as the case may be. The arc suppression unit may form part of the control unit.

[0012] The controller and / or the at least one arc suppression unit may be implemented as independent software modules, which may be executed on the same processor of the plasma generator or on separate processors.

[0013] In one embodiment, the switching unit has at least one third switching unit output configured to be connected to at least another process chamber or a sink, and wherein the switching unit is configured to selectively apply the output signal as a pulse to one of the switching unit outputs for a predetermined pulse duration in response to an input control signal of the control unit for more efficient utilization of the plasma generator. The switching unit may have at least one switching unit output configured to be connected to a sink, wherein the switching unit is configured to selectively apply the output signal as a pulse to the switching unit output for the sink for a predetermined pulse duration in response to an input control signal for avoiding or preventing overload or arcing in the process chamber.

[0014] To achieve simple coordination, the control unit can be configured so that it coordinates the sum of pulse durations and corresponding pulse intervals at each switching unit output so that the sums are the same, or so that the sum of one switching unit output is a multiple of the sum of another switching unit output.

[0015] Preferably, the control unit may be configured to shift the pulses in time relative to the power demand in case that the power demand would cause an overlap of pulses on different outputs, wherein the corresponding time shift is selected such that the energy output by each output substantially corresponds to the power demand within the time range. Alternatively or additionally, the control unit may be configured to divide each pulse relative to the power demand into two separate pulses and shift them in time in case that the power demand would cause an overlap of pulses on different outputs, wherein the corresponding division and time shift are selected such that the energy output by each output substantially corresponds to the power demand within the time range. Additionally or alternatively, the control unit may also be designed to shift each pulse in time relative to the power demand in case that the power demand would cause an overlap of pulses on different outputs, wherein the corresponding time shift is selected such that the energy output by each output substantially corresponds to the power demand within the time range. According to a preferred embodiment, the control unit is designed to be able to change at least one of the following parameters of the pulses: the position of the pulse in the pulse sequence, the division of the pulse into sub-pulses, the pulse duration and the amplitude of the pulse in case that a specific power demand would cause an overlap of pulses on different outputs.

[0016] According to another embodiment, the plasma generator is configured to pulse power with a frequency of at least 40 kHz to at least three process chambers and further comprises the following components: a control unit, which is configured to obtain and evaluate process data about the processes in the at least three process chambers; another controllable power supply unit with an output, the power supply unit being configured to output a direct current with a predetermined voltage and / or intensity at its output in the form of a control signal of the corresponding control unit; and another switching unit with a power input, which is connected to the output of the power supply unit and has at least three switching unit outputs for connection to one of the at least three process chambers, respectively; wherein the switching unit is configured to control the power supply unit to the output of the power supply unit. The invention is configured to form an alternating current with a predetermined frequency of at least 40 kHz from the direct current on the input as an output signal, and selectively output the output signal as a pulse to one of the switching unit outputs within a predetermined pulse duration in response to a control signal of the control unit; wherein the control unit is configured to coordinate the power requirements of the at least three process chambers and control the power supply unit and the switching unit so that at each of the switching unit outputs connected to the process chamber, the power corresponding to the power requirement is substantially provided as a pulse within a time range, wherein the pulses provided to the process chamber by the switching unit are staggered in time, and the pulses of the two switching units can overlap. This can increase the flexibility of pulse coordination. The power supply unit can have different rated powers to accommodate various power requirements.

[0017] The invention also relates to a plasma processing apparatus having at least two separate process chambers in which a plasma can be generated in each of the process chambers, and having a plasma generator of the aforementioned type, wherein each of the process chambers is connected to one of the switching unit outputs of the switching unit.

[0018] In one embodiment, such a plasma processing apparatus has at least three separated process chambers, wherein the switching unit of the plasma generator has at least three switching unit outputs, and each of the process chambers is connected to one of the switching unit outputs. In addition, the plasma processing apparatus may also have an absorber, wherein the switching unit of the plasma generator has at least three switching unit outputs, and the absorber is connected to one of the switching unit outputs.

[0019] The present invention also relates to a method for pulse supplying power having a predetermined frequency of at least 40 kHz to at least two separated process chambers, comprising the following steps: providing a direct current having a predetermined voltage and / or intensity at an input of a switching unit in response to a control signal of a control unit; forming an alternating current output signal having a predetermined frequency of at least 40 kHz from the direct current in the switching unit, and selectively outputting the alternating current output signal as a pulse having a predetermined pulse duration at one of at least two switching unit outputs of the switching unit in response to a control signal of the control unit, each of the switching unit outputs being connected to one of the at least two separated process chambers; wherein the control unit generates a control signal for providing the direct current and a control signal for selectively outputting the alternating current output signal in response to power requirements of the at least two process chambers and in response to process data regarding processes in the at least two process chambers, the control signals being coordinated so that power corresponding to the power requirements is substantially provided as pulses within a time range at each of the switching unit outputs connected to the process chambers, wherein the pulses for the process chambers are staggered in time but the process chambers operate synchronously. This method achieves the advantages of more efficient utilization of the plasma generator already mentioned above.

[0020] In case a specific power requirement would lead to an overlap of pulses on different outputs, the control unit preferably changes at least one of the following parameters of the pulses: the position of the pulse in the pulse train, the division of the pulse into sub-pulses, the pulse duration and the amplitude of the pulse. The process is thus flexible and can be adapted to various requests. The control unit can make adjustments according to predetermined fixed rules or rules that can be set by the operator. The control unit can compare the power output in the pulses within a time period with the power requested within this time period for each process chamber and automatically adjust at least one parameter of the pulses according to the comparison.

[0021] In one embodiment, power is provided to at least three separated process chambers, wherein the switching unit has at least three switching unit outputs, each of which is connected to one of the at least three separated process chambers; wherein the control unit generates a control signal for providing direct current and a control signal for selectively outputting an alternating current output signal in response to power requirements of the at least two process chambers and in response to process data regarding processes in the at least three process chambers, and wherein the control signals are coordinated so that power corresponding to the power requirement is substantially provided as pulses within a time range at each of the switching unit outputs connected to the process chambers, wherein the pulses for the process chambers are staggered in time, but the process chambers operate synchronously.

[0022] In terms of the method, the switching unit may have at least three switching unit outputs, one of which is connected to an absorber configured to receive and absorb power, and wherein the control unit is capable of monitoring the processes in each process chamber and detecting an arc phenomenon or arc hazard in one of these process chambers, and in response thereto, forwarding the output signal to the absorber rather than to the corresponding process chamber within the range of the pulse duration or at least a portion thereof.

[0023] In one embodiment of the method, the control unit coordinates the sums of pulse durations and corresponding pulse intervals at each switching unit output so that these sums are the same or so that the sum at one switching unit output is a multiple of the sum at another switching unit output.

[0024] In another embodiment, the method is for pulsed supply of power having a predetermined frequency of at least 40 KHz to at least three separated process chambers, and has the following additional steps: providing a direct current having a predetermined voltage and / or intensity at an input of another switching unit in response to a control signal of a control unit; forming an alternating current output signal having a predetermined frequency of at least 40 KHz from the direct current in another switching unit, and, in response to a control signal of the control unit, selectively outputting the alternating current output signal as a pulse having a predetermined pulse duration at one of at least three switching unit outputs of the another switching unit, Each of the switching unit outputs is connected to one of at least three separated process chambers; wherein the control unit generates a control signal for providing direct current and a control signal for selectively outputting an alternating current output signal in response to the power requirements of the at least three process chambers and in response to process data related to the processes in the at least three process chambers, and these control signals are coordinated so that at each of the switching unit outputs connected to the process chamber, power corresponding to the power requirement is substantially provided as a pulse within a time range, wherein the pulses output by one of the switching units are staggered in time, but the pulses of two switching units may overlap in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is described in detail below with reference to the accompanying drawings; wherein:

[0026] Figure 1 FIG. 4 is a schematic diagram of a plasma processing apparatus including a plasma generator according to the present invention.

[0027] Figure 2 FIG. 4 is a schematic diagram of an alternative plasma processing apparatus including an alternative plasma generator according to the present invention.

[0028] Figure 3 FIG. 4 is a schematic diagram of another alternative plasma processing apparatus including another alternative plasma generator according to the present invention.

[0029] Figure 4(A) to Figure 4(D) is a pulse sequence emitted by a plasma generator, wherein FIG4(A) shows a conventional pulse sequence of a common plasma generator, and Figure 4(B) to Figure 4(D) Show according to Figure 1 Different exemplary pulse sequences emitted by the plasma generator.

[0030] Figure 5(A) to Figure 5(D) is a schematic diagram of the pulse sequence, where Figure 5(A) to Figure 5(D) Show according to Figure 2 Different exemplary pulse sequences emitted by the plasma generator.

[0031] 6(A) and 6(B) are schematic diagrams of pulse sequences, wherein FIG. 6(A) shows a pulse sequence request of a process chamber, and FIG. 6(B) shows a pulse sequence request of a process chamber according to Figure 2 An exemplary pulse sequence is issued by a plasma generator in response to a pulse sequence request.

[0032] FIG. 7(A) and FIG. 7(B) are based on Figure 3 Schematic diagram of an exemplary pulse sequence emitted by a plasma generator, wherein two schematic diagrams arranged one above the other show the outputs on different switching units of the plasma generator.

[0033] 8(A) and 8(B) are schematic diagrams of pulse sequences, wherein FIG. 8(A) shows a pulse sequence request of a process chamber, and FIG. 8(B) shows a pulse sequence request of a process chamber according to Figure 2 An exemplary pulse sequence is issued by a plasma generator in response to a pulse sequence request.

[0034] 9(A) and 9(B) are schematic diagrams of pulse sequences, wherein FIG. 9(A) shows a pulse sequence request of a process chamber, and FIG. 9(B) shows a pulse sequence request of a process chamber according to Figure 2 An exemplary pulse sequence is issued by a plasma generator in response to a pulse sequence request.

[0035] 10(A) and 10(B) are schematic diagrams of pulse sequences, wherein FIG. 10(A) shows a pulse sequence request of a process chamber, and FIG. 10(B) shows a pulse sequence request according to Figure 2 An exemplary pulse sequence is issued by a plasma generator in response to a pulse sequence request. DETAILED DESCRIPTION

[0036] In this specification, the expressions will substantially include a deviation of + / - 5% (preferably + / - 2%) from the stated values.

[0037] Figure 1Schematic diagram of a first embodiment of a plasma processing device 1 with two process units 3a, 3b and a plasma generator 5. The process units 3a and 3b can have an identical structure and each have a chamber for accommodating one or more substrates, in particular semiconductor wafers or PV substrates. The process chambers can be tightly closed and the process units 3a and 3b have different components (not shown) for adjusting the desired environmental conditions in the individual process chambers, such as pumps and gas cabinets. Each process chamber is also assigned a dedicated pump, while a gas cabinet can supply several process chambers as appropriate. Components for generating plasma are also provided in the process chambers, wherein these components can be formed, for example, by a wafer boat, which is, for example, introduced into the process chamber together with the substrates and is electrically contacted there, as described in the above-mentioned DE 10 2015 004 419 A1, which is incorporated into the present disclosure to this extent.

[0038] The process units 3a, 3b are connected to the plasma generator 5 via power cables 7a or 7b and data connections 8a or 8b. The plasma generator 5 supplies power with a frequency of more than 40 kHz to each process unit 3a and 3b via power cables 7a, 7b. Data can be exchanged between the process units 3a, 3b and the plasma generator 5 via data connections 8a or 8b. The data connections 8a or 8b can be implemented wired or wirelessly. The process units 3a, 3b can in particular supply the plasma generator 5 with various process data about the processes in the respective process chambers. In particular, actual data about the actual power input, the presence of plasma, etc. can be transmitted here, but also corresponding nominal data (soll-data), for example, in the case of existing plasma processing systems with a single process unit and a single plasma generator.

[0039] The plasma generator 5 has a controllable power supply unit 10, a switching unit 12 and a control unit 14. The power supply unit has an input and an output not shown, and the output is connected to the input of the switching unit 12 through a power cable 15. The power supply unit 10 is configured to output a direct current with a predetermined voltage and / or intensity in response to a control signal of the control unit 14, which is known in the art.

[0040] The switching unit 12 has the input already mentioned, which is connected to the power cable 15 for receiving direct current from the power supply unit 10, and has two separated outputs, one of which is connected to the power cable 7a and the other is connected to the power cable 7b. The switching unit 12 has a converter circuit, which is capable of forming an alternating current with a predetermined frequency of at least 40 kHz from the direct current on the input as an output signal. The converter circuit may, for example, have a bipolar transistor, which forms a quasi-sinusoidal signal (a step-shaped signal) from the direct current provided by the power supply unit 10. The switching unit 12 also has a switching component, which applies the output signal thus formed to one or the other output in response to a control signal of the control unit 14, thereby applying it to the process unit 3a or the process unit 3b.

[0041] As shown, the control unit 14 in turn has two separate controllers 16a, 16b, and an arc suppression unit 18. The controllers 16a, 16b are connected to the process unit 3a or 3b via a data connection 8a or 8b. The controllers 16a, 16b are each configured to determine the power requirements of the process units 3a, 3b based on actual data and nominal data about the processes in the process units 3a, 3b. The controllers 16a, 16b (or downstream units) then create control data for the power supply unit 10 and the switching unit 12 based on these power requirements. Although the controllers 16a, 16b are shown as separate independent units, they can also be constructed as a single unit, which enables substantially parallel processing of the data of the process units 3a and 3b. The controllers 16a, 16b can in particular be implemented as software routines that can be executed substantially in parallel, which are executed on a processor.

[0042] In the embodiment shown, the corresponding output of the controller is connected to the corresponding input of the arc suppression unit 18. Thus, the arc suppression unit 18 can obtain the power requirements of the process units from the controllers 16a, 16b, or directly obtain the control data for the power supply unit 10 and the switching unit 12 created accordingly. In addition, the arc suppression unit 18 can also obtain unprocessed data directly from the process units 3a, 3b. Such data are in particular data that enable the following assessment to be performed in real time: whether an arc has occurred in one of the process units 3a and 3b, or whether an arc is about to occur. The data required for this purpose and the corresponding detection algorithms are known to those skilled in the art and will not be described here in detail. In the event of an arc or an arc hazard being detected, the arc suppression unit 18 can adjust the control signals transmitted to the power supply unit 10 and the switching unit 12, and briefly interrupt the power supply to the process units 3a, 3b where an arc has occurred or where a corresponding hazard exists.

[0043] In the present embodiment, the arc suppression unit 18 can also be constructed so that the control data for the power supply unit 10 and the switching unit 12 are generated accordingly when the power demand data of each process unit is obtained. Of course, if these control data are already generated by the controllers 16a, 16b, this solution is no longer necessary. In addition, the arc suppression unit 18 is constructed so that it coordinates the control data for the power supply unit 10 and the switching unit 12 generated by itself or by the controllers 16a, 16b. The control data for the power supply unit 10 and the switching unit 12 must be coordinated in this way so that power is provided to each process unit 3a, 3b according to the power demand. However, the control data for the power supply unit 10 and the switching unit 12 also need to be coordinated in time, because at each time point, power can only be provided at one of the outputs of the switching unit. As described above, power is provided to each process unit 3a, 3b as a pulse with a specific pulse duration. Therefore, the pulses are coordinated by the control data for the power supply unit 10 and the switching unit 12 so that these pulses do not overlap, wherein the process chambers can still work synchronously.

[0044] Figure 2 Schematic diagram of an alternative embodiment of a plasma processing apparatus 1, which in this embodiment has three process units 3a, 3b, 3c, an absorber 20 and a plasma generator 5. The same or similar elements in different embodiments are denoted by the same reference numerals.

[0045] The process units 3a, 3b and 3c may be the same as described above and are connected to the plasma generator 5 via power cables 7a, 7b or 7c and data connections 8a, 8b or 8c. The power cables 7a, 7b and 7c are also used to provide power with a frequency greater than 40 KHz from the plasma generator 5 to each process unit 3a, 3b and 3c. Data can also be exchanged between the process units 3a, 3b, 3c and the plasma generator 5 via the data connections 8a, 8b and 8c.

[0046] The plasma generator 5 also has a controllable power supply unit 10, a switching unit 12 and a control unit 14. The power supply unit 10 may be the same as described above. The switching unit 12 also has an input connected to the output of the power supply unit via a power cable 15. However, in this embodiment, the switching unit has four separate outputs, three of which are connected to power cables 7a, 7b or 7c, and the fourth output is connected to the absorber via a power cable 21.

[0047] The switching unit 12 also has a converter circuit and a switching component as described above, which selectively applies the output signal formed by the converter circuit to one of the outputs in response to a control signal of the control unit 14. Therefore, the output signal can be selectively applied to one of the process units 3a to 3c or to the absorber 20.

[0048] In this embodiment, the control unit 14 also has three separate controllers 16a, 16b and 16c, and an arc suppression unit 18. The controllers 16a, 16b and 16c are connected to the process units 3a, 3b or 3c via respective data connections 8a, 8b or 8c. The controllers 16a, 16b and 16c may also be of the type described above and are configured to determine the power requirements of the respective process units 3a, 3b or 3c and, as the case may be, also determine control data for the power supply unit 10 and / or the switching unit 12.

[0049] The arc suppression unit 18 may also be substantially of the type described above, wherein the arc suppression unit in this embodiment monitors the three process cells 3a, 3b and 3c to prevent arcs. The arc suppression unit also coordinates the pulses provided by the switching unit 12 to the three process cells 3a, 3b and 3c.

[0050] In this embodiment, the arc suppression unit 18 can also be configured to generate control data for the power supply unit 10 and the switching unit 12 based on the power requirements of each process unit. Of course, if the control data are generated by the controllers 16a and 16b, this solution is no longer necessary.

[0051] Furthermore, the arc suppression unit 18 is constructed such that it coordinates control data for the power supply unit 10 and the switching unit 12 generated by itself or by the controllers 16a, 16b, 16c. The control data for the power supply unit 10 and the switching unit 12 must provide coordination of the power to the individual process units 3a, 3b, and 3c according to the power demand. However, the control data for the power supply unit 10 and the switching unit 12 also need to be coordinated in time, because at each point in time, power can only be provided at one of the outputs of the switching unit. As described above, the power is provided to each process unit 3a, 3b, and 3c as a pulse with a specific pulse duration. Therefore, the pulses are coordinated by the control data for the power supply unit 10 and the switching unit 12 so that they do not overlap, wherein the process chambers can still operate synchronously.

[0052] Although the arc suppression unit 18 is shown as a single unit which assumes both the arc suppression function and the pulse coordination function, it is also possible to implement these functions in separate units. For the arc suppression function, the evaluation of the process data and the control data can be carried out separately for each of the process chambers, and three units can be provided accordingly (for example, implemented as independent parallel software routines). In the event that the arc suppression function detects an arc or an arc hazard, it can divert the pulse originally intended for one of the process cells 3a, 3b and 3c into an absorber 20 instead of introducing it into each process cell 3a, 3b and 3c, wherein the absorber is configured to absorb the power pulse and convert it into heat, for example. This switching can be carried out for the entire pulse or a sub-pulse, which will be explained in detail below.

[0053] For the pulse coordination function, data, in particular the power requirements of the individual process units or the desired control data for the power supply unit 10 and the switching unit 12, must be combined in a coordination routine. This coordination routine can be run in the arc suppression unit 18 as described above or in a separate pulse coordination unit. In the coordination routine, the power requirements of the individual process units determined by the controller or the control data for the power supply unit 10 and the switching unit 12 created therefrom are combined and checked for conflicts. In addition, data about the power supply unit 10 and the switching unit 12, such as switching times, maximum power, maximum pulse duration (if limited), are also taken into account in this check. Other data about the individual process units 3a, 3b, 3c and the running process can also be taken into account. Such data can include, for example, time tolerances in the pulse input, tolerances on the pulse amplitude, the minimum required and / or maximum permissible energy input for the process, and, if appropriate, other parameters. These data can remain constant or change within the process. Thus there are processes in which at certain points in time a precise pulse sequence with a defined cycle length and a specific pulse amplitude must be followed, while at other points in the process the cycle length and the pulse amplitude are quite flexible but the energy input lies within narrower tolerances within the time range.

[0054] Based on these data, the coordination unit is able to coordinate the output pulses at the output of the control unit. Preferably, in each process unit 3a, 3b, 3c, a process is implemented which allows setting a cycle length (sum of pulse duration and pulse interval) which is the same or, for one of the processes, an integer multiple of the cycle length of the other process. As will be explained in detail below in conjunction with the pulse diagram, this greatly simplifies the coordination, but is not necessary. Different coordination schemes are explained in detail below in conjunction with the pulse diagram.

[0055] Figure 3Schematic diagram of another alternative embodiment of the plasma processing apparatus 1. In this embodiment, five process units 3a to 3e, an absorber 20 and a plasma generator 5 are provided. The same or similar elements in different embodiments are still denoted by the same reference numerals.

[0056] The process units 3a to 3e may be the same as described above and are connected to the plasma generator 5 via power cables 7a to 7e and data connections 8a to 8e. The power cables 7a to 7e are also used to provide power with a frequency greater than 40 KHz from the plasma generator 5 to each process unit 3a to 3e. Data can also be exchanged between the process units 3a, 3b, 3c and the plasma generator 5 via data connections 8a, 8b and 8c.

[0057] In this embodiment, the plasma generator 5 has two controllable power supply units 10a, 10b, two switching units 12a, 12b, and a control unit 14. The power supply units 10a, 10b may be the same as the power supply units described above. The power supply units 10a, 10b may be the same or different in terms of rated power. The switching units 12a, 12b each have an input, which is connected to the output of one of the power supply units via a power cable 15a or 15b. In this embodiment, the switching units 12a, 12b each have six separate outputs, five of which are connected to power cables 7a to 7e and thus to process units 3a to 3e, and the sixth output is connected to the absorber 20 via a power cable 21.

[0058] Each of the switching units 12a and 12b has a converter circuit and, as described above, has a switching component that selectively applies an output signal formed by the converter circuit to one of the outputs in response to a control signal from the control unit 14. Therefore, the output signal of each switching unit 12a and 12b can be selectively applied to one of the process units 3a to 3e or to the absorber 20.

[0059] In this embodiment, the control unit 14 again has five separate controllers 16a to 16e, and an arc suppression unit 18. The controllers 16a to 16e are connected to the process units 3a to 3e via data connections 8a to 8e. The controllers 16a to 16e can also be of the type described above and are configured to determine the power requirements of the respective process units 3a to 3e and, as the case may be, also determine control data for the power supply unit 10 and / or the switching unit 12.

[0060] The arc suppression unit 18 monitors the five process cells 3a to 3e in this embodiment to prevent arcs. The arc suppression unit is also configured to distribute and coordinate the pulses required by the process cells 3a to 3e through two power supply units 10a, 10b and two switching units 12a, 12b.

[0061] Since the arc suppression unit 18 is able to distribute the required pulses to the two power supply systems (combination of power supply unit and switching unit), the flexibility in the distribution of pulses is greatly increased. In this case, in particular, pulses that overlap in time can also be provided when this is necessary due to the power requirements, as will be explained in detail below. A corresponding coordination requires that the pulses are provided sequentially at the switching unit 12a or 12b, but the switching units 12a, 12b can be controlled in such a way that they provide the pulses simultaneously. In the case of simultaneous provision of pulses by separate switching units 12a, 12b, however, these pulses need to be applied to the individual process units 3a to 3e.

[0062] Although the arc suppression unit 18 is shown as a single unit which assumes both the arc suppression function and the pulse coordination function, these functions can also be implemented in separate units, in particular when coordination becomes complicated and, if appropriate, has a negative impact on the arc suppression function.

[0063] The plasma generator 5 is also shown as a single plasma generator with two separate power supply systems. Of course, two separate plasma generators 5 can also be provided, each of which is connected to the process unit 3a to 3e and the absorber, and these plasma generators are coordinated accordingly by a common control unit. However, it is preferred to use a single unit, because the communication between the arc suppression unit 18 and the power supply units 10a, 10b and the switching units 12a, 12b is achieved via real-time data connections, which are mechanically sensitive and should be avoided as much as possible.

[0064] It is understood by those skilled in the art that the number of process units to be supplied and the structure of the plasma generator are not limited to the specific embodiments shown. Figure 3 As shown, more process units can also be supplied with power by one plasma generator. In the case of a larger number of process units, three power supply systems can also be provided in the plasma generator, for example, wherein the complexity of pulse coordination increases with the number of process chambers and power supply systems. However, according to the present invention, the number of process units should be higher than the number of available power supply systems, in particular at least twice.

[0065] Consider, for example, the following plasma processing system: a plasma generator having eight process units (+1 optional absorber) and a plasma generator with two separate power supply systems, such as Figure 3 As shown, there may be two separate plasma generators and a common control unit.

[0066] For the pulse coordination function, the same data as described above can also be collected in this embodiment.

[0067] Figure 4(A) to Figure 7(B) Different exemplary pulse sequences are shown which may be provided by the plasma generator 5 of the present invention.

[0068] FIG4(A) shows a typical pulse sequence currently provided by a plasma generator. For a predetermined duration t of, for example, 5 ms on An alternating current pulse 30 having a frequency of at least 40 KHz and a predetermined power (P) is output. This is followed by a pulse interval t of, for example, 45 ms. off , this pulse interval is followed by a duration t on Another pulse of, for example, 5 ms. This is a typical sequence of power pulses provided when a plasma process is carried out in a process cell. In this case, a period of 50 ms and a duty cycle of 0.1 are produced. Thus, for example 90% of the available continuous power of the used plasma generator is not utilized here.

[0069] FIG. 4(B) shows an alternative pulse sequence, for example, Figure 1 The plasma generator shown is capable of providing this pulse sequence. The exemplary pulse sequence consists of pulse 30 and pulse 40, wherein, for example, pulse 30 is provided to process cell 3a and pulse 40 is provided to process cell 3b. For this pulse sequence, pulses 30 and 40 each have the same power and the same pulse duration t, for example, 5 ms. on Between pulses 30-30 / 40-40, for each process unit 3a / 3b, there is a pulse interval t of, for example, 45 ms. off Between pulses 30-40-30, a pulse interval t of, for example, 20 ms is generated. off Each individual process unit 3a, 3b operates at a duty cycle of 0.1, while the plasma generator operates at a duty cycle of 0.2, so the load factor is significantly improved.

[0070] FIG. 4(C) shows another exemplary pulse sequence, for example, Figure 1The plasma generator shown is capable of providing this pulse sequence. The exemplary pulse sequence is also composed of pulse 30 and pulse 40, wherein, for example, pulse 30 is provided to process unit 3a and pulse 40 is provided to process unit 3b. For this pulse sequence, pulses 30 and 40 each have different powers, but have the same pulse duration t, for example, 5 ms, as shown in FIG. 4(B). on As shown in the figure, the plasma generator can not only stagger the same pulses, but also provide pulses with different powers, which can be achieved by corresponding control of the power supply unit 10, for example.

[0071] FIG. 4(D) shows another exemplary pulse sequence, for example, Figure 1 The plasma generator shown is capable of providing this pulse sequence. The exemplary pulse sequence is also composed of pulse 30 and pulse 40, wherein, for example, pulse 30 is provided to process unit 3a and pulse 40 is provided to process unit 3b. In terms of this pulse sequence, pulses 30 and 40 also have different powers as shown in FIG. 4(C), and also have different pulse durations t. on , for example, 15 ms for pulse 30 and 5 ms for pulse 40. The pulse intervals between pulses 30-40 are, for example, 10 ms, and the pulse intervals between pulses 40-30 are, for example, 20 ms. It can be seen that pulses for plasma processes having the same cycle length (or cycle lengths that are multiples of each other) are easy to interleave and can be provided by a single plasma generator.

[0072] However, processes with different cycle lengths which are not multiples of each other can also be provided by a single plasma generator. For this purpose, since only one pulse can be provided for one process unit at a point in time, a pulse shift in time of one pulse and / or another pulse, or a division and partial shift of the pulses can be used, as will be explained in detail below in conjunction with Figures 6(A) and 6(B). Here, an attempt is made to meet the requirements of each process unit, so that, for example, the shift / division is only performed within the permissible tolerance. In particular, in order to control the power supply system (combination of power supply unit and switching unit), the corresponding control unit can evaluate the corresponding data and, as appropriate, also predict one or more cycles in order to predict when conflicts between pulses will occur, so that a shift can be prepared as appropriate. For example, the maximum pulse interval t in the process offIf the normal pulse interval is 45ms-50ms, but an offset of +10ms is required in two cycles, an offset of +5ms can be made in each of the two consecutive cycles, so that a pulse interval of 50ms is produced in the two consecutive cycles. However, it is preferred to choose the offset so that the energy input to the process corresponds to the power demand over a longer period of time, such as 50 cycles, or remains unchanged within this time range.

[0073] Figure 5(A) to Figure 5(D) Different exemplary pulse sequences are shown, which can be obtained, for example, by Figure 2 The plasma generator 5 is provided. For example, three different pulses 30, 40, 50 are provided for different process units 3a to 3c.

[0074] FIG5(A) shows a pulse sequence comprising pulses 30, 40, 50, each of which has the same pulse duration t, for example, 5 ms. on Between pulses 30-30 / 40-40 / 50-50, for each process unit 3a / 3b / 3c, there is a pulse interval t of, for example, 45 ms. off A pulse interval t of, for example, 10ms-15ms-10ms is generated between pulses 30-40-50-30 off Each individual process unit 3a, 3b operates at a duty cycle of 0.1, while the plasma generator operates at a duty cycle of 0.3.

[0075] FIG5(B) also shows a pulse sequence including pulses 30, 40, 50, but the pulse durations of these pulses are t on However, the pulses 30-30 / 40-40 / 50-50 each have the same cycle length, for example, 50 ms, so that the pulses are easily staggered.

[0076] FIG. 5(C) shows another exemplary pulse sequence similar to FIG. 5(B) comprising pulses 30, 40, 50, the pulse durations of which are t on In addition, pulses 30-30 / 40-40 each have the same cycle length, for example 50 ms, while pulse 50-50 has twice the cycle length, for example 100 ms. In this case, interleaving of pulses can also be easily achieved.

[0077] FIG. 5(D) shows another exemplary pulse sequence similar to FIG. 5(B) comprising pulses 30, 40, 50, the pulse durations of which are t onAlthough the pulses 30-30 / 40-40 / 50-50 have different powers, they each have the same period length. However, this pulse sequence exemplifies the intervention of the arc suppression unit 18 in a conventional pulse sequence. Therefore, the arc in the process unit 3c is already determined during the first half of the second pulse 50, and the arc suppression unit 18 controls the switching unit 12 in real time accordingly, so that the second half of the pulse 50 is transferred to the absorber. This process is fast enough and does not cause power fluctuations in subsequent pulses, which may occur when the process unit 3c is simply separated from the plasma generator 5, because the power is already provided in the switching unit.

[0078] FIG. 6(A) shows exemplary pulse sequence requirements (power requirements) for three process chambers, which may be determined by Figure 2 The arc suppression unit 18 is processed and coordinated, and an exemplary pulse sequence is shown in FIG. 6(B), which is composed according to Figure 2 The plasma generator emits in response to the pulse sequence requirement.

[0079] As shown in Fig. 6 (A), pulses 30, 40, 50 with different pulse durations and different powers are requested, wherein corresponding request profiles are generated, for example, by controllers 16a to 16c. In addition, pulses 30-30 / 40-40 / 50-50 also have different cycle lengths, so the pulse sequence requests pulses in a partially overlapping or directly consecutive manner.

[0080] Since this cannot be achieved, the arc suppression unit 18 or another control unit must coordinate the pulses to be output in such a way that these pulses are output in an appropriate manner, wherein the requirements of the process units are taken into account as much as possible. In the example shown in Figures 6(A) and 6(B), it is assumed that the pulse 30 is not allowed to undergo any changes, because the corresponding process unit does not allow deviations at least during the current phase of the process. The output pulse 30 (see Figure 6(B)) therefore corresponds exactly to the requested pulse. The processes in the process units 3b and 3c allow deviations in the pulses within predetermined limits, while the total energy output remains constant over time. Therefore, the first pulse 50 in Figure 6(B) is slightly shifted forward in time relative to its request (this request is directly adjacent to the pulse request for pulse 30), so that the control unit 12 has a buffer of, for example, 1 ms. The second pulse 50, which completely overlaps with the pulse 30 according to the pulse request, is divided into two parts 50-1, 50-2, wherein the part 50-1 is located before the corresponding pulse 30 in time, and the part 50-2 is shifted in time after the pulse 30. In this case, the sum of the durations of the sub-pulses 50-1, 50-2 is equal to the duration of the normal pulse 50. In addition to this division, the pulse 50 can also be completely shifted after the pulse 30 as appropriate without exceeding the maximum allowed pulse interval between the pulses 50-50. The third and fourth pulses 40 can also be shifted in time to achieve a reasonable pulse sequence. In the case that none of the overlapping pulses need to be emitted at a specific time point, both can also be shifted, usually in opposite directions. One of them is shifted forward and the other is shifted backward. In this way, the requested pulse interval between the same pulses in the chamber can be better maintained as appropriate.

[0081] 6(A) and 6(B) illustrate different schemes for generating pulse trains based on the determined power requirements and the requirements of the process unit. A person skilled in the art can understand various pulse coordination schemes from the basic principles of the present invention, which can also be predictive as described above.

[0082] In addition to or as an alternative to the shifting and / or splitting of the pulses, the individual pulse heights and / or the individual pulse durations can also be varied. Examples of this are shown in FIGS. 8(A) and 8(B). FIG. 8(A) shows an exemplary pulse sequence request (power demand) for three process chambers, while FIG. 8(B) shows an exemplary pulse sequence output. The pulse sequence request is in particular identical to FIG. 6(A), and the pulse 30 is again considered as unchangeable. However, the pulse sequence output according to FIG. 8(B) differs from the pulse sequence output according to FIG. 6(B). The first pulse 50 is not shifted forward in time as in FIG. 6(B). Rather, the pulse start point corresponds to the request. However, the pulse is shortened in time, for which the power is increased. Thus, a higher power is provided for a short duration, so that the total power of the pulse is equal to or approximately equal to the requested power. The second pulse 50 is not split, but is shifted in time after the overlapping requested pulse 30. As with the first pulse 50, the pulse is shortened in time and the power is increased at the same time. Compared with segmentation, the above scheme helps, for example, to maintain a minimized pulse interval between successive pulses of the chamber. The third pulse 40 is processed in a manner similar to the first pulse 50, i.e., the requested start time is maintained, while the pulse duration is shortened and the pulse height is increased. For the fourth pulse 40, the start time is offset, but the end time according to the application is maintained. The pulse duration is also shortened thereby, which is compensated by increasing the pulse height. Therefore, FIG. 8 (B) shows an alternative pulse management, which does not use pulse offsets at all when achieving the same output position as FIG. 6 (A). The offset of the start time and the end time relative to the request is considered as a pulse offset. In the case where at least one of the time points is implemented according to the request, it is not considered as an offset.

[0083] Those skilled in the art can understand from FIG. 8(A) and FIG. 8(B) that, in addition to pulse shifting and division, other schemes for pulse coordination are provided. Of course, these schemes can also be integrated with each other, in particular, pulses can be shifted and pulses can be modulated in terms of pulse height and / or pulse duration.

[0084] In the case where one of the above measures is not feasible or appropriate, although not shown, the pulse can also be completely ignored. However, in this case, the energy input within the time range should not be significantly affected. In the case where, for example, a minimum energy input per unit time (e.g., milliseconds) is not allowed, the concept "within the time range" may be relatively short as the case may be, because the corresponding unit time needs to be taken into account here. However, in the case where, for example, the energy fed into the process as a whole is essentially of interest, the concept may also include the entire process itself. For a shorter time period, for example, in the case of a complete or partial failure of a pulse, the previous and / or the next pulse may be increased or extended accordingly as the case may be. For a longer time period, the pulse may also be provided significantly later as the case may be, for example, after the planned end of the process. The pulse management is configured so that, taking into account the performance of the inserted components (e.g., the power supply unit 10 and / or the switching unit 12), the best configuration consisting of pulse duration, pulse offset, pulse power level and / or pulse splitting is selected for each request of the chamber. The smallest possible process impact is considered to be the best. In order to improve the constant energy input, it is also possible not only to vary pulses that overlap or are adjacent in time. The pulse management can be implemented as independent hardware, for example, or integrated into the control unit, in particular the controller.

[0085] FIG. 7(A) and FIG. 7(B) also show an exemplary pulse sequence, which is obtained according to Figure 3 A pulse sequence is provided by a plasma generator via switching units 12a, 12b, wherein two schematic diagrams arranged one above the other show outputs at different switching units 12a, 12b of the plasma generator.

[0086] As power requirements, pulses 30, 40, 50 with the same pulse duration, the same period length between pulses and the same power should be provided, which, for example, reach three process units 3a to 3c that are synchronously carrying out the same process. In addition, however, pulses 60 and 70 with different pulse durations, pulse periods and powers need to be generated for process units 3d to 3e, wherein each pulse 70 overlaps in time with one of the pulses 60. The requirements for process units 3d and 3e must not be offset.

[0087] In this case, the control unit finds a division of pulses, wherein the switching unit 12a mainly outputs pulses 30, 40, 50, and the switching unit 12b mainly outputs pulses 60 and 70. However, since the switching unit 12b does not allow pulses 60 and 70 to be offset, and there is an overlap in terms of the request in each case where pulse 70 is required to be output, the required pulse 60 is output by the switching unit 12a at the time point when pulse 70 is output by the switching unit 12b. As shown in Figures 7(A) and 7(B), this solution can be realized without the need for offsetting pulses 30, 40 and 50. However, if it does not conflict with the requirements of the process units 3a to 3c, it is also possible to provide an empty space between pulses 30, 40 and / or 50 to receive pulse 60 if necessary.

[0088] As shown in the figure, in terms of the creation of pulse sequences, Figure 3 The plasma generator 5 provides greater flexibility, thereby being able to meet the power requirements of several process units while taking each requirement into consideration. Other specific pulse management schemes are described in detail below.

[0089] Pulse-off-time analysis analysis)

[0090] In the following, a pulse offset scheme using pulse off-time analysis is introduced, whereby the pulse offset leads to an offset of subsequent pulses for the same chamber (wherein the pulses for each chamber are also referred to as pulses of a channel in the following) as appropriate. In this case, the following rules apply:

[0091] a. Changes in pulse length and pulse height are not allowed.

[0092] b The pulse interval between pulses is the minimum time, but can be extended if necessary.

[0093] c. The first requested pulse must be output first, and the pulses on the other channels must wait and then be fully output. The resulting pulse off-time extension (the extended interval time between the previous pulse and the shifted pulse) is not subtracted from the next pulse off-time. Therefore, the subsequent pulses are shifted backwards by the amount of the pulse off-time extension.

[0094] d. If two pulses are requested at exactly the same time, the shorter pulse is output first, followed by the longer pulse. If the pulses are identical, the pulse on the first channel is output first. In the case of several channels, the output is carried out in a defined output sequence.

[0095] e. The pulse offset leads to an increase in the pulse off time within a time range. A moving average should be calculated based on this. This value indicates the average extension of the entire pulse off time within the time range. This is referred to as the pulse off time increase (Puls-Aus-Zeit-Erh hung).

[0096] FIG9(A) and FIG9(B) illustrate this scheme in conjunction with a system having two chambers (channels), wherein FIG9(A) shows a pulse request and FIG9(B) shows the corresponding pulse output. As shown in FIG9(A), the third and fourth requested pulses 30 and 40 overlap, wherein for the third pulse transmission, pulse 30 should start before pulse 40. Therefore, as shown in FIG9(B), for the third pulse transmission, pulse 30 is output first, followed by pulse 40. For the fourth pulse transmission, pulse 40 is output first, followed by pulse 30. However, the fourth pulse 40 is shifted backward relative to its requested profile, and the shift time is the same as the shift of the third pulse backward, so as to avoid the interval time between the third and fourth pulses falling below the requested interval time (minimum interval time). Therefore, after a pulse is shifted, the subsequent pulses will be shifted accordingly.

[0097] The advantage of this solution is that the waiting time of the generated slave pulse does not need to be subtracted from the interval time. In this way, unintended feedback can be avoided. However, this solution may lead to an increase in the pulse off time in the time range, which in turn leads to a reduction in power output. Different measures can be used to compensate for this, such as a prolongation of the total process in the relevant chamber corresponding to the moving average value. Other exemplary measures will be described below.

[0098] Pulse offset using pulse off-time compensation

[0099] In order to compensate for the increased pulse off time in the time period, the above rules a to e can be supplemented by the following rule.

[0100] f. The user must enter an offset value that reduces the waiting time of the pulse by a fixed set value. This value is selected by the user based on a measured moving average and is not fed back during the process. This scheme is shown in the following equation.

[0101] Pulse off time Puls X = set pulse off time Puls X -Compensation value

[0102] If the moving average value results in a prolongation of the pulse off time of, for example, 2%, the compensation value can be set accordingly. For 2%, for example, a compensation value of 1 μs can be entered for a set pulse off time of 50 μs. This compensation value is used fixedly during the process.

[0103] Pulse offset using pulse off-time compensation

[0104] Another approach to compensate for the increased pulse off time in the time period is to calculate relative values. To this end, the following rules can be added to rules a to e.

[0105] g. Enter a compensation value as a percentage, which reduces the interval time between successive pulses by a randomly assigned percentage value between 0% and the entered compensation value. For example, in the case of 10%, a window of 45μs to 50μs for the interval time is generated for a set pulse interval time of 50μs. This value is selected by the user and no further feedback is performed. This scheme is shown in the following formula.

[0106] Pulse off time Puls X = set pulse off time Puls X *(100-X)

[0107] Here, X is a random value in % between 0% and the input compensation value. This value is fixedly set and used during the process.

[0108] Pulse offset using pulse off-time compensation with feedback

[0109] Another alternative to compensate for the increased pulse off time over the time period is compensation with feedback. To make the plasma generator easier to use, the compensation value is automatically determined, entered and adjusted by integration. However, in some cases this may result in unwanted vibrations due to feedback. Algorithms can be used to detect and suppress such possible vibrations in advance, if necessary.

[0110] To this end, the following rules are added to the above rules a to e.

[0111] h. Determine the compensation value based on the determined pulse-off time extension. To this end, the pulse-off time extension is multiplied by a proportionality factor K. K can be selected by the user and corresponds to a damping factor in the case of K<1 and to a gain factor in the case of K>1. This scheme is shown in the following formula.

[0112] Compensation value = K * pulse off time extension

[0113] Pulse off time = set pulse off time - compensation value

[0114] These formulas can be applied to each pulse.

[0115] Pulse offset using pulse time keeping

[0116] The pulse time keeping scheme is used to avoid power loss and complex compensation mechanisms as described above. The following rules are used here:

[0117] a. Changes in pulse length and pulse height are not allowed.

[0118] b. The interval time between successive pulses of a channel is flexible and can be shortened or prolonged as required.

[0119] c. The first requested pulse is output first, and the pulses on other channels are shifted backward in time (the pulse off time to the previous pulse of the channel is extended) and are completely output. Accordingly, the extension of the pulse off time is subtracted from the pulse off time to the next pulse of the same channel, so that the next pulse is output with a shortened pulse off time.

[0120] Therefore, each pulse is output at the requested time point without overlapping with the pulse of another channel. The shift of one pulse will not cause the shift of the subsequent pulses of the same channel.

[0121] Pulse failure with priority

[0122] Another approach to pulse management is to at least partially ignore the pulses by giving priority to one of the pulses. For this purpose, the following rule is generated, for example:

[0123] a. Changes in pulse height are not allowed.

[0124] b. The pulse interval is fixed and is not allowed to change.

[0125] c. The output pulses have a priority list, and important pulses are always outputted before unimportant pulses, while low-priority pulses can be completely disabled or only partially outputted.

[0126] d. Determine the integration of the failed pulses and obtain the total pulse failure.

[0127] FIG. 10(A) and FIG. 10(B) illustrate this scheme in conjunction with a system having two chambers (channels), wherein FIG. 10(A) shows a pulse request and FIG. 10(B) shows the corresponding pulse output. As shown in FIG. 10(A), the third and fourth requested pulses 30 and 40 overlap. In this example, pulse 30 has a higher priority, so it is always output as requested, as shown in FIG. 10(B). The third and fourth pulses 40 are output after being shortened. For the third pulse 40, the start is moved after the end of pulse 30, and it will be maintained according to the end of the requested profile. For the fourth pulse 40, the pulse starts as requested, but ends early, especially before the requested time point (and output) of the overlapping requested pulse 30.

[0128] (Partial) deactivation of the pulses may significantly reduce the power input, so a solution to this problem is defined in the following.

[0129] Pulse failure using pulse number compensation

[0130] In order to compensate for (partially) failed pulses according to the “pulse failure with priority” approach, the corresponding rules a to d may alternatively be supplemented by the following rules.

[0131] e. Based on the sum of pulse failures determined in d, output the number of failure pulses at the end of the adjustment pulse sequence.

[0132] Since the process result usually depends strongly on the total power delivered, pulse failure can be compensated for, for example, by simply extending the process time, provided that the pulse failure does not lead to process termination.

[0133] Pulse failure using pulse power and / or pulse duration compensation

[0134] In order to suppress the power reduction, the pulse duration and / or the pulse power can be changed, wherein the pulse duration change includes a deviation from the normal (requested) pulse duration and is not a simple pulse offset. Rules a to d according to the "pulse failure with priority" scheme can be adjusted as follows and supplemented by the following rules:

[0135] a. Pulse height changes are only allowed within predefined limits.

[0136] b. It is permitted to change, in particular shorten, the intervals within predetermined limits, depending on the circumstances.

[0137] c. The output pulses have a priority list, and important pulses are always outputted before unimportant pulses, while low-priority pulses can be completely disabled or only partially outputted.

[0138] d Determine the proportion of pulses that fail due to overlap.

[0139] e. Determination of the extent to which the failure ratio of pulses can be compensated by shifting the pulse start / pulse end and / or by increasing the pulse to pulse ratio within predetermined limits, taking the interval time into account.

[0140] f. Shift the pulse start / pulse end to and / or increase the pulse within predefined limits.

[0141] In this case, for example, the shift of the pulse start / pulse end can be prioritized over the pulse increase, so that an attempt is first made to compensate for the failure proportion of the pulse by the shift and then by the remaining proportion of the pulse increase (if it can be done completely). However, it is also possible to define priorities or set weights.

[0142] Of course, it is also possible to allow only a shift in the pulse start / pulse end or a pulse increase.

[0143] The above-mentioned different solutions can be combined with each other to realize various solutions for technicians in this field according to specific process requirements.

[0144] The invention has been described above with reference to preferred embodiments, but the invention is not limited to these specific embodiments. In particular, the plasma generator can be used in various process units, and the number of process units to be supplied with power by the plasma generator can be different from the number shown. Figure 3 For the embodiment of the present invention, the switching units 12a and 12b do not need to be connected to all process units 3a to 3e. Therefore, for example, only process units 3a to 3c can be connected to the switching unit 12a, and process units 3c to 3e can be connected to the switching unit 12b, so that only process unit 3c can be controlled by both. This reduces flexibility, but the power supply to at least one of the process units is always achieved through the two switching units, thereby resolving possible conflicts in the establishment of pulse sequences.

Claims

1. A plasma generator for pulse supplying power having a frequency of at least 40 KHz to at least two process chambers, the plasma generator comprising: a control unit configured to obtain and evaluate process data regarding the processes in the at least two process chambers; a controllable power supply having an output, the controllable power supply being configured to output direct current having a predetermined voltage and / or intensity at its output in response to a control signal from the control unit; as well as a switching unit having a first input connected to the output of the power supply and having at least two switching unit outputs for respectively connecting to one of the at least two process chambers; wherein the switching unit is configured to form an alternating current having a predetermined frequency of at least 40 kHz from the direct current on the first input as an output signal, and to selectively output the output signal as a pulse to one of the switching unit outputs within a predetermined pulse duration in response to a control signal from the control unit; wherein the control unit is configured to coordinate power requirements of the at least two process chambers, and drive the power supply and the switching unit so that power corresponding to the power requirements is substantially provided as pulses at the output of each switching unit connected to the process chamber within a time period, wherein the pulses of each process chamber are staggered in time so that the process chambers can operate synchronously; and The control unit is configured to shift the pulses or parts thereof in time relative to the power demand if the power demand would cause an overlap of pulses on different outputs, wherein the corresponding time shift is selected so that the energy output via each output corresponds to the power demand within the time range.

2. The plasma generator according to claim 1, wherein the control unit has a plurality of controllers corresponding to the number of process units to be connected to the switching unit, wherein each of the controllers is configured to obtain process data regarding a process in one of the process chambers, wherein each of the controllers is connected to the power supply and / or the switching unit to control these elements in a manner responsive to the received process data.

3. The plasma generator according to claim 2 , further comprising at least one arc suppression unit, the arc suppression unit being configured to obtain and evaluate in real time current process data about the processes in the at least two process chambers and current data of the power supply and / or the switching unit for detecting an arc or an impending arc, wherein the arc suppression unit is connected to the power supply and / or the switching unit for controlling these elements in response to a detected arc or an impending arc, wherein the arc suppression unit may constitute a part of the control unit.

4. The plasma generator according to claim 3, wherein the controller and / or the at least one arc suppression unit are implemented as independent software modules, and the software modules can be executed on the same processor or on different processors of the plasma generator.

5. The plasma generator of claim 1 , wherein the switching unit has at least one third switching unit output configured to be connected to at least another process chamber, and wherein the switching unit is configured to selectively apply an output signal as a pulse to one of the switching unit outputs for a predetermined pulse duration in response to a control signal input by the control unit.

6. The plasma generator according to claim 1, wherein the control unit is configured to coordinate the sum of the pulse duration and the corresponding pulse interval at each switching unit output so that the sums are the same, or so that the sum at one of the switching unit outputs is a multiple of the sum at another switching unit output.

7. The plasma generator according to claim 1, wherein the control unit is further configured to perform at least one of the following steps: where the power demand would cause pulses on different outputs to overlap, dividing the single pulse into two separate pulses relative to the power demand and shifting them in time, wherein the division of the corresponding pulses and the time shifting are selected so that the energy output by each output substantially corresponds to the power demand within the time range; and in case the power demand would cause pulses on different outputs to overlap, shifting a single pulse in time relative to the power demand, wherein the respective time shift is selected such that the energy output by each output corresponds to the power demand within the time range, In case a specific power requirement would result in an overlap of pulses on different outputs, at least one of the following parameters of the pulses is varied: the position of the pulse in the pulse train, the division of the pulse into sub-pulses, the pulse duration and the amplitude of the pulse.

8. The plasma generator of claim 1 for pulsing power having a frequency of at least 40 KHz to at least three process chambers, wherein the control unit is configured to obtain and evaluate process data regarding processes in the at least three process chambers and the plasma generator further comprises the following components: another controllable power supply having an output, configured to output direct current having a predetermined voltage and / or intensity at its output in response to a control signal from the control unit; as well as another switching unit having a power input connected to the output of the another controllable power supply having an output and having at least three switching unit outputs for respectively connecting to one of the at least three process chambers; wherein the further switching unit is configured to form an alternating current with a predetermined frequency of at least 40 kHz from the direct current on the power input as an output signal, and to selectively output the output signal as a pulse to one of the switching unit outputs within a predetermined pulse duration in response to a control signal from the control unit; The control unit is configured to coordinate the power requirements of the at least three process chambers and to control the power supplies and the switching units so that power corresponding to the power requirements is substantially provided as pulses within a time range at each of the switching unit outputs connected to the process chambers, wherein the pulses provided to the process chambers by a switching unit are staggered in time, while the pulses of the two switching units may overlap, wherein the power supplies may have different rated powers.

9. A plasma processing apparatus comprising at least two separated process chambers, wherein plasma can be generated in each process chamber, and having a plasma generator according to any one of claims 1 to 8, wherein the process chambers are each connected to one of the switching unit outputs of the switching unit.

10. The plasma processing apparatus according to claim 9, having at least three process chambers, wherein the switch unit of the plasma generator has at least three switch unit outputs, and each of the process chambers is connected to one of the switch unit outputs.

11. A method for pulse supplying power, wherein the method pulse supplies power having a predetermined frequency of at least 40 KHz to at least two process chambers, the method comprising the following steps: providing a direct current having a predetermined voltage and / or intensity at an input of the switching unit in response to a control signal of the control unit; forming an alternating current output signal having a predetermined frequency of at least 40 KHz from the direct current in the switching unit, and selectively outputting the AC output signal as pulses at one of at least two switching unit outputs of the switching unit in response to a control signal from a control unit, each of the switching unit outputs being connected to one of the at least two process chambers; wherein the control unit generates control signals for providing direct current and control signals for selectively outputting alternating current output signals in response to power demands of the at least two process chambers and in response to process data regarding processes in the at least two process chambers, wherein the control signals are coordinated so that power corresponding to the power demands is substantially provided as pulses over time at each of the switching unit outputs connected to the process chambers, wherein the pulses for the process chambers are staggered in time but the process chambers operate synchronously, and Wherein, in case a specific power requirement would result in an overlap of pulses on different outputs, the control unit changes at least one of the following parameters of the pulses: the position of the pulse in the pulse sequence, the division of the pulse into sub-pulses, the pulse duration and the amplitude of the pulse.

12. The method according to claim 11, wherein the control unit is adjusted according to predetermined fixed rules or rules that can be set by an operator, or The control unit compares the power output in a pulse within a time period for each process chamber with the power requested within the time period, and automatically adjusts at least one parameter of the pulse according to the comparison.

13. The method of claim 11, wherein power is provided to at least three process chambers, wherein the switch unit has at least three switch unit outputs, each of the switch unit outputs being connected to one of the at least three process chambers; and The control unit generates a control signal for providing direct current and a control signal for selectively outputting an alternating current output signal in response to power requirements of the at least three process chambers and in response to process data regarding processes in the at least three process chambers, the control signals being coordinated so that power corresponding to the power requirements is provided as pulses within a time range at each of the switching unit outputs connected to the process chambers, wherein the pulses for the process chambers are staggered in time but the process chambers operate synchronously.

14. The method according to claim 11, wherein the control unit coordinates the sum of the pulse duration and the corresponding pulse interval at each switching unit output so that the sums are the same, or so that the sum at one switching unit output is several times the sum at another switching unit output.

15. The method of claim 11 for pulsing power having a predetermined frequency of at least 40 KHz to at least three separate process chambers, having the following additional steps: Providing a direct current having a predetermined voltage and / or intensity at an input of another switching unit in response to a control signal of the control unit; forming an AC output signal having a predetermined frequency of at least 40 kHz from the DC power in the other switching unit, and selectively outputting the AC output signal as a pulse having a predetermined pulse duration at one of at least three switching unit outputs of the other switching unit in response to a control signal of a control unit, each of the switching unit outputs being connected to one of the at least three process chambers; The control unit generates a control signal for providing direct current and a control signal for selectively outputting an alternating current output signal in response to power requirements of the at least three process chambers and in response to process data regarding processes in the at least three process chambers, wherein the control signals are coordinated so that at each of the switching unit outputs connected to the process chamber, power corresponding to the power requirements is substantially provided as pulses with a predetermined pulse duration within a time range, wherein the pulses output by one of the switching units are staggered in time, but the pulses of two switching units may overlap in time.

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