WO2019219537A1

WO2019219537A1 - Device and method for determining an electrical power reflected by a plasma

Info

Publication number: WO2019219537A1
Application number: PCT/EP2019/062065
Authority: WO
Inventors: Christian Bock; Sai Gautam JANAKI PREMKUMAR
Original assignee: TRUMPF Hüttinger GmbH + Co. KG
Priority date: 2018-05-15
Filing date: 2019-05-10
Publication date: 2019-11-21
Also published as: KR20210007973A; JP2021524147A; DE102018111562A1; JP7443347B2

Abstract

A device for determining an electrical power reflected by a plasma, wherein the plasma can be acted on by a first high-frequency power signal having a first frequency and by at least one second high-frequency power signal having at least a second frequency, the second frequency being smaller than the first frequency. The device is designed to determine a first variable characterising a power in the range of the first frequency which is reflected by the plasma and a second variable characterising the power in a first frequency range which is reflected by the plasma, the first frequency range having a predefinable number of sum frequencies and/or difference frequencies formed from the first frequency and an integer multiple of the second frequency. The device can differentiate between the power in the range of the first frequency which is reflected by the plasma and the power in the aforesaid first frequency range which is reflected by the plasma.

Description

Title: Apparatus and method for determining a plasma reflected electrical power

description

Field of the invention

The disclosure relates to a device for

Determining an electrical power reflected by a plasma, wherein the plasma is acted upon by a first high-frequency power signal having a first frequency and at least one second high-frequency power signal having at least one second frequency, the second frequency being smaller than the first frequency.

The disclosure further relates to a corresponding method for determining a plasma reflected from electrical power or to operate a corresponding device.

State of the art

It is known conventional plasma systems, like them

For example, for etching processes in the semiconductor manufacturing can be used to supply by Hochfreguenzgeneratoren high frequency energy with different Freguenzen ("Mehrfreguenzsysteme" or "Mehrfreguenz plasma systems").

For example, such Mehrfreguenzsysteme be supplied by a first conventional Hochfreguenzgenerator with the above-mentioned first Hochfreguenzleistungssignal first Freguenz and by a second conventional Hochfreguenzgenerator with a second Hochfreguenzleistungssignal second Freguenz. However, the conventional high-frequency generators providing the first and second high-frequency power signals for the operation of such a multi-frequency system are i.d.R. not optimized for operation in a multi-frequency system.

Description of the invention

Preferred embodiments relate to a

Device of the type mentioned, wherein the device is adapted to determine a first size, which characterizes a power reflected by the plasma in the range of the first frequency and to determine a second size, which reflects a reflected power from the plasma in a first frequency range characterized, wherein the first

Frequency range has a predetermined number of sum frequencies and / or difference frequencies from the first frequency and an integer multiple of the second frequency. With a "power reflected by the plasma", it is possible here to mean both the power components that are part of a first Generator were supplied to the plasma and reflected by this example because of mismatch and so get to the device, as well as those power delivered by a second generator to the plasma in which

Plasma have led to mixed products with the first signal and are guided by the plasma to the device.

In this case, the device can in particular between the

Plasma reflected power in the range of the first frequency and the plasma reflected power in the said first frequency range differentiate.

Investigations by the Applicant arise in a

Multi-frequency system among other things by nonlinearities

(For example, saturation effects) in the plasma mixed products from the introduced into the plasma

High-frequency power signals of different frequency, which also at an ideal impedance or Leistungsanpassung example of that high-frequency generator, which provides the first high-frequency power signal at the first frequency, to the first frequency provided by the first high-frequency generator "reflected

Although the above-mentioned mixed products are only produced when the two high-frequency power signals of different frequencies interact in the plasma, they are for the first, for example

These mixing products, which may also be referred to as "sidebands", show that the plasma is excited at both frequencies, which is desirable, so are not undesirable per se, yet produce they undesired heat loss and / or overvoltages in the first high-frequency power signal High-frequency generator. Derived from the mixed products

However, according to Applicant's study, the resulting reflected power represents a different loading of the first high-frequency generator than a reflected power at the first frequency, which is also referred to below

Fundamental frequency is called.

The principle according to the embodiments allows

advantageous between one of the plasma reflected

Power in the range of the first frequency, so for example, the fundamental frequency, and a reflected power from the plasma in said first frequency range

differentiate. Preferably, the first frequency range comprises at least a portion of those described above

Mixed products. In other words, the first quantity represents a power reflected by the plasma in the region of the first frequency, for example fundamental frequency, and the second variable represents a power of at least part of the said mixed products reflected by the plasma. By determining the first and second quantities, operation of the plasma of a multi-frequency system can be more accurately characterized and evaluated. Furthermore, an actual load of the first high-frequency generator or its

Components are determined more precisely than conventional systems. This also greatly increases the safety and reliability of such plasma systems, e.g. from failure, fire and destruction. It is important to consider that on the one hand, the plasma systems themselves are very complex and expensive, and this ever increasing. So you expect every 1 to 2 years with a doubling of complexity in the

Semiconductor manufacturing, which causes even faster rising prices in the manufacturing plants. In addition, there is a failure The systems are also very expensive, as are provided by the ever-increasing complexity more and more modules on a wafer. In the event of a failure or incorrect measurement, entire wafers can be destroyed. To an increasing extent, this is not only undesirable, but must be associated with a constantly growing

Probability to be excluded.

Although primarily the first high-frequency generator or the application of the principle of the embodiments to the first high-frequency generator is described below, the principle of the embodiments without limiting the generality can alternatively or additionally also be applied to the second

Radio frequency generator are transmitted. At further

Embodiments are also conceivable, the principle of

Embodiments apply to multi-frequency plasma systems with more than two high-frequency generators.

In further preferred embodiments, it is provided that the first frequency range does not include the first frequency. This can ensure that the second size alone contains proportions of the mixed products, but not the first frequency.

In further preferred embodiments, it is provided that the sum frequencies can be determined as a function of the equation fs_n = fl + n * f2, and / or that the

Difference frequencies are determined in dependence on the equation fd_n = fl - n * f2, where fs_n is an n-th sum frequency, where fl is the first frequency, where n is a natural number greater than zero, where the multiplication operator, where f2 is the second frequency and where fd_n is an nth difference frequency. In further preferred embodiments it is provided that the predefinable number of sum frequencies or

Differential frequencies is at least two, in particular

at least three. Because mixed products with higher order

(larger values for n) one decreasing with the order

Signal energy, it may in preferred

Be sufficient embodiments, for example, two

Sum frequencies and two difference frequencies to consider. In further embodiments, it may be provided that only a sum frequency fs_l = fl + f2 and a difference frequency fd_l = fl-f2 are considered, e.g. to determine the second size from this.

In each case, further embodiments are preferred

at least one sum frequency and at least one

Considered difference frequency. Namely, according to investigations by the Applicant, mixed products of the same order but different frequency positions may each contain a different signal energy with respect to the first frequency. In these cases, this is a precise characterization of the power reflected by the plasma in the first

Frequency range allows.

In further preferred embodiments, it is provided that the first frequency is between about 10 MHz, megahertz, and about 190 MHz, wherein in particular the first frequency has at least about one of the following values: 13.56 MHz, 27.12 MHz, 40.68 MHz, 60 MHz, 81 MHz, 161 MHz. Other embodiments also have other values for the first one

Frequency possible.

In further preferred embodiments it is provided that the second frequency is between about 10 kHz, kilohertz, and is about 2.3 MHz, wherein in particular the second frequency has at least about one of the following values: 300 kHz,

400 kHz, 500 kHz. In other embodiments, other values for the second frequency are possible.

In further preferred embodiments, in which

at least one further, so third high frequency generator is provided, it is possible that of the third

High frequency generator generated RF power signal has the first frequency or the second frequency or is in a different frequency range, e.g. below the second frequency or between the first and second frequencies or above the first frequency.

In further preferred embodiments, it is provided that the device is designed to determine the first variable and / or the second variable as a function of a first signal, which comprises a voltage wave reflected by the plasma to a first high-frequency generator providing the first high-frequency power signal

characterized. This allows efficient determination of the first and second sizes. The first signal can be obtained, for example, by means of a directional coupler, which connects the first high-frequency generator with, for example, a plasma chamber containing the plasma or which is arranged on a high-frequency line which is the first

High frequency generator connects to the plasma chamber. In further preferred embodiments, the first

High-frequency generator via a matching network ("Matchbox") be connected to the plasma chamber, which allows in a conventional manner, an impedance matching of the plasma load, for example, based on the first frequency In further preferred embodiments, a voltage and / or current extraction may be provided to determine the first signal.

In further preferred embodiments, it is provided that the device is designed to transmit the first signal or a signal derived therefrom by means of a signal

Downconversion to transform into a second signal, wherein in particular the second signal is a baseband signal. In other words, the first signal or the signal derived therefrom by the

Downconversion of a frequency shift e.g. subjected to smaller frequencies according to the first frequency. This allows an efficient and cost effective

Processing the second signal. In further preferred embodiments, the second signal may also be

Be intermediate frequency signal, the down conversion, the first signal or a signal derived from the first signal thus transform into an intermediate frequency position.

In further preferred embodiments, it is provided that the device is designed to receive the first signal or a signal derived therefrom

Local oscillator signal to mix to obtain the second signal.

In further preferred embodiments, it is provided that the local oscillator signal has at least approximately the first frequency. Investigations by the Applicant According to it, it is sufficient if the local oscillator signal at least approximately the first frequency corresponds (a deviation of up to 2% is justifiable). An exact

Correspondence of a frequency of the local oscillator signal with The first frequency is therefore dispensable, which causes a further simplification.

In further preferred embodiments, it is provided that the device is designed to derive a third signal from the second signal by means of at least one first low-pass filtering with a first cutoff frequency, wherein in particular the device is designed to determine the first variable as a function of the third signal. The first cut-off frequency for the first low-pass filtering is preferably selected such that the third signal has only signal components which characterize a power reflected by the plasma in the range of the first frequency, but not such signal components, which are the mixed products of first frequency and second frequency belong.

In further preferred embodiments, it is provided that the first cutoff frequency is approximately less than or equal to the second frequency, preferably smaller than the second

Frequency. As a result, it can be ensured that the third signal has only signal components which have a power reflected by the plasma in the region of the first frequency

In particular, the third signal has no signal components associated with the mixing products.

In further preferred embodiments, it is provided that the device is designed to derive a fourth signal from the second signal by means of a second low-pass filtering with second cut-off frequency, wherein

in particular, the device is designed to determine the second variable as a function of the fourth signal and the first variable. In further preferred embodiments, it is provided that the second cutoff frequency is greater than the second cutoff frequency

Frequency, preferably greater than three times the second frequency. This ensures that the fourth signal has, in particular, also those signal components which belong to the mentioned mixing products. In addition, the fourth signal also corresponds to the fundamental frequency

Signal components on.

In further preferred embodiments, it is provided that the device is designed to determine a third variable a) as the sum of the first variable and the second variable and / or b) as a function of the fourth signal. In further preferred embodiments, the third quantity characterizes a power reflected by the plasma in the range of the first frequency (for example fundamental frequency) plus the power of at least some mixed products reflected by the plasma.

In further preferred embodiments, it is provided that the device is designed to determine a fourth variable as a function of the first size and the third size, in particular as a weighted sum of the first size and the third size, the first size being a first size

Weighting factor is assigned, and wherein the third size is associated with a second weighting factor. On

Weighting factor can be a scalar or complex size. With this weighting factor, the size can be multiplied. This can be advantageous for example one

different loading of an output stage of the first high-frequency generator by the respective reflected power components, represented by the first size and the third size, are taken into account. At further In preferred embodiments, the fourth size may advantageously be used to regulate a power of the first

High frequency power signal or the first

High frequency generator can be used. For that, the

Device according to the embodiments, for example, be configured to the fourth size of the first

Radio frequency generator to transmit the first

High frequency power signal generated.

In further preferred embodiments it is provided that the device is designed to determine a fifth size as a function of the first size and the second size, in particular as a weighted sum of the first size and the second size, wherein the first size is associated with a third weighting factor , and wherein the fourth size is associated with a fourth weighting factor. This also advantageous, for example, a different

Load an output stage of the first

High frequency generator by the respective reflected power components, represented by the first size and the second size, are taken into account. At further

preferred embodiments may be the fifth size

advantageous for controlling a power of the first

High frequency power signal or the first

High frequency generator can be used.

In further preferred embodiments, it is provided that the device is designed to determine an, in particular complex-valued, impedance of the plasma,

in particular a temporal course of the impedance of the

Plasma. In further preferred embodiments, the time course of the impedance of the plasma may be e.g. as

Trajectory can be mapped in a Smith chart. In further preferred embodiments, a phase measurement for determining the impedance can be carried out, for example between a voltage wave running to the plasma and a voltage wave returning from the plasma to the first high-frequency generator. For further preferred

Embodiments may be used to determine the (i.o., complex) impedance with respect to the first frequency, e.g. from the mentioned back and forth

Voltage wave derived signals with comparatively narrow band filtering around the fundamental frequency. If an optional down conversion takes place, cf. the above remarks on the second signal may e.g. by a comparatively strong low-pass filtering (low

Cut-off frequency) of the respective baseband signal a 2-tuple of signals (a first signal, the returning

Voltage wave characterized, analogous to the second signal s.o., and a second signal, the corresponding

incoming voltage wave characterized), from which the impedance with respect to the fundamental frequency

can be determined. Accordingly, further

Embodiments for a current complex impedance of the plasma to use a less heavily filtered signal. Applicant's study suggests that, in further preferred embodiments, the impedance, in particular also the instantaneous values of the impedance, can be applied to a position of the trajectory of the impedance in the complex plane, e.g.

Figure 3 illustrates in a Smith chart and thus the type of stress (e.g., thermal, electrical) of the first

High-frequency generator by the reflected power

getting closed. In other words, in some embodiments, by a strong filtering the signals characterizing the back and forth voltage waves and determining the impedance thereof for the impedance iw a point, so a certain value in the complex plane or a

corresponding Smith chart. This value may be used in other embodiments as so-called "matching information" because it characterizes the impedance matching of the first high frequency generator to the plasma at the fundamental frequency In the case of filtering, which allows only signal components of the sidebands, the corresponding determined

"Impedance" exclusively information about effects of

Mixture.

In further preferred embodiments it is provided that the device is designed to additionally the fourth size and / or the fifth size in dependence of

To determine impedance of the plasma, especially in

Dependence of the time course of the impedance of the plasma. Thereby, e.g. also a phase of the i.d.R. Complex impedance of the plasma are taken into account. This is particularly useful in those embodiments in which the fourth and / or fifth size, for example, to control a

Power of the first high-frequency power signal or the first high-frequency generator is used.

In further preferred embodiments it is provided that the device is designed to at least one of its operating variables, in particular at least one of

output the following quantities to an external unit and / or via a display device: the first size, the second size, the third size, the fourth size, the fifth size. In preferred embodiments, an output of at least one of said quantities to an external unit may include, for example, transmitting the respective quantities to a radio frequency generator that generates the first radio frequency power signal. For example, an output power of the first high-frequency power signal can be carried out in response to the device-transmitted quantity (s). The visual output is a trajectory of impedance across a display device at others

Embodiments also conceivable.

Further preferred embodiments relate to a method for operating a device for determining an electrical power reflected by a plasma, wherein the plasma has a first high-frequency power signal having a first frequency and a second high-frequency power signal having at least one second frequency

High frequency power signal is acted upon, wherein the second frequency is smaller than the first frequency, wherein the device determines a first size, one of the

Plasma reflected power in the range of the first frequency characterized and determines a second size, which reflects a power reflected by the plasma in a first

Frequency domain characterized, with the first

Frequency range has a predetermined number of sum frequencies and / or difference frequencies from the first frequency and an integer multiple of the second frequency.

In this case, the device can in particular between the

Plasma reflected power in the range of the first frequency and differentiate the power reflected by the plasma in said first frequency range.

Further preferred embodiments relate to a high-frequency generator for generating at least one first high-frequency power signal having a first frequency with at least one device according to the embodiments.

In further preferred embodiments it is provided that the high-frequency generator is designed to, the

Generation of the first high-frequency power signal,

in particular by means of a first regulator, as a function of at least two of the following variables: first size, second size, third size, fourth size, fifth size.

In other preferred embodiments may also

be provided that the high frequency generator the

Device according to the embodiments does not contain, but is adapted to receive at least one of the following sizes of the device according to the embodiments

(For example, via a data interface between the device and the high-frequency generator) and the generation of the first high-frequency power signal, in particular by means of a first regulator, in response to at least two of said variables: first size, second size, third size, fourth size, fifth size.

In further preferred embodiments, it is provided that the high-frequency generator has a first control channel for at least one of the following variables: first size, second size, third size, fourth size, fifth size, and a second control channel for at least one of the following: first Size, second size, third size, fourth size, fifth size. Particularly preferred For example, a first control channel for the first size and, for example, a second control channel for the second size provided.

In further preferred embodiments, it is provided that the high-frequency generator is designed to produce an output power of the first high-frequency power signal as a function of a time profile of the impedance of the

To regulate plasma. This corresponds to preferred

Embodiments of a control of the output power in

Dependence of a trajectory of the impedance or the position of the trajectory, beispielswese plotted in a Smith chart. This can advantageously be achieved that for the high frequency generator or its output stage

in terms of the impedance of the plasma comparatively

critical operating conditions (e.g., having undesirable values for the phase of the impedance) can be reduced or avoided.

In further preferred embodiments it is provided that an impedance transformation (in particular phase rotation) of the impedance of the plasma (or the resulting impedance of the plasma and an optionally present matching network) takes place as a function of the time profile of the relevant impedance. In other words, an impedance transformation, in particular in the sense of a phase rotation, the impedance of the plasma, for example, depending on a position of the

Trajectory of the impedance in the Smith chart done.

As a result, the trajectory of the impedance can be rotated about its origin in the Smith chart so as to lie in relatively less critical regions of the complex plane represented by the Smith chart. For example, depending on the topology of an output circuit of the high frequency generator areas different criticality can be defined, and in preferred embodiments by the

Phase rotation avoidance of particularly critical areas, so unwanted values for the time course or the phase of the impedance can be achieved.

The above-mentioned impedance transformation, in particular phase rotation, can in some preferred embodiments, for example, be achieved by adapting a line length between the plasma or the optional matching network and the high-frequency generator. In further preferred embodiments, said impedance transformation, in particular phase rotation, can also take place dynamically, that is to say in particular at a transit time of the high-frequency generator.

For this purpose, for example, a corresponding

Phase shifter between the high frequency generator and the plasma or the optional matching network

be provided. Combinations of an adaptation of the

Line length and a dynamic phase rotation by means of phase shifter are in further preferred

Embodiments also conceivable.

Further preferred embodiments relate to a use of a device and / or a method according to the embodiments for transmitting the first size and the second size to a display device and / or to a machine-readable interface for distinguishable

Presentation and / or processing of the two sizes.

Further preferred embodiments relate to a use of a device and / or a method according to the embodiments for controlling a

High frequency generator, wherein for the scheme, the first size and the second size, each with different

Non-zero weighting factors are included in the scheme.

Impedanzanpassungsvorrichtung, in particular a

Adaptation network, where for the scheme, the first size and the second size, each with different

Weighting factors are included in the scheme, in particular the first size with a magnitude larger weighting factor than the second size.

Other features, applications and advantages of the invention will become apparent from the following description of embodiments of the invention, which are illustrated in the figures of the drawing. All described or illustrated features form for themselves or in any

Combination of the subject invention, regardless of their combination in the claims or their dependency and regardless of their formulation or representation in the description or in the drawing.

In the drawing shows:

Figure 1 shows schematically a simplified block diagram of a

Device according to one embodiment in a target system,

FIG. 2A,

2B, 2C each schematically a power density spectrum

according to further embodiments, FIG. 3A schematically shows a simplified block diagram of a further embodiment,

FIG. 3B shows schematically a simplified block diagram of a further embodiment,

FIG. 4 shows schematically a simplified block diagram of a further embodiment,

FIG. 5 schematically shows a simplified block diagram of a further embodiment,

FIG. 6 schematically shows a spectral representation of FIG

High frequency power signals according to an embodiment,

Figure 7 schematically shows a metrologically determined

Spectral representation of

High frequency power signals according to an embodiment,

FIG. 8 schematically shows a time profile of an impedance of a plasma according to an embodiment, shown in a Smith chart,

FIG. 9

to 12 each schematically a time course of a

Impedance of a plasma according to one embodiment shown in a Smith chart,

FIG. 13 schematically shows a simplified block diagram of a

High frequency generator according to an embodiment,

FIG. 14 schematically shows a simplified block diagram of a

High frequency generator according to another

embodiment, FIG. 15 schematically shows a simplified flowchart of a method according to an embodiment,

FIG. 16 schematically shows a simplified block diagram of a further embodiment, and

FIG. 17 shows a configuration according to another

Embodiment.

Figure 1 shows schematically a simplified block diagram of a multi-frequency plasma system comprising a plasma chamber PC and a plasma P which can be generated therein. The plasma P can be used, for example, for material processing such as e.g. to the

Coating or etching semiconductor devices, etc.

be used. A first high-frequency generator 200 generates a first frequency having a first frequency, which is also referred to below as a fundamental frequency

High-frequency power signal LSI, the plasma chamber PC and thus the plasma P via a corresponding high-frequency line 210 can be fed. The plasma P accordingly represents an electrical load for the first high-frequency generator 200. A voltage wave Ui from the first high-frequency generator 200 to the plasma P, which corresponds to the first high-frequency power signal LSI, is also shown in FIG. It contains i.d.R. (especially in a steady state) only the fundamental frequency.

In preferred embodiments it is provided that the first frequency is between about 10 MHz, megahertz, and about 190 MHz, wherein in particular the first frequency has at least about one of the following values: 13.56 MHz, 27.12 MHz, 40.68 MHz , 60 MHz, 81 MHz, 161 MHz. At further

Embodiments are also other values for the first one

Frequency possible. Optionally, a matching network 220 may be arranged between the first high frequency generator 200 and the plasma chamber PC, which preferably effects impedance matching of the plasma P impedance such that power reflected from the plasma P toward the first high frequency generator 200 is at the first frequency is reduced. If available, forms the optional

Adaptation network 220 together with the plasma P the

electrical load for the first high frequency generator 200. A first line section 210a of the high frequency line 210 connects the first high frequency generator 200 to the first high frequency generator 200

optional customization network 220. A second

Line section 210b connects the optional one

Adaptation network 220 with the plasma chamber PC.

In addition to the first high-frequency power signal LSI, the plasma P is also present with a second one

High-frequency power signal LS2 can be acted upon, which generated by a second high-frequency generator 300 or

can be provided. The second

High frequency power signal LS2 has a second frequency that is less than the first frequency.

In further preferred embodiments, it is provided that the second frequency is between approximately 10 kHz, kilohertz, and approximately 2.3 MHz, wherein in particular the second frequency has at least approximately one of the following values: 300 kHz,

Multi-frequency plasma systems of the type depicted in FIG. 1 can be advantageously used in applications in which both a high ion density and a high acceleration of the Ions is desired, for example, for a material processing such as the already mentioned etching.

In the high-frequency excitation of the plasma P, according to preferred embodiments, attention is paid to a good impedance matching, which is characterized by the lowest possible electrical power, which is not reflected by the load

distinguished. Thus, on the one hand, the e.g. from the first high frequency generator 200 in the form of

High-frequency power signal LSI used optimally for exciting the plasma P and on the other hand stress (especially thermal or electrical type, such as too high temperature and / or voltage) for the first

High frequency generator 200 avoided. For this, in further preferred embodiments, between the first

Radio frequency generator 200 and the plasma chamber PC uses the already mentioned optional matching network 220, e.g. can be regulated in order to obtain an impedance matching with changing process parameters. Alternatively or additionally, a so-called "frequency tuning" can be carried out for impedance matching in further embodiments, that is to say a change in the first frequency of the high-frequency power signal LSI delivered by the first high-frequency generator.

Investigations by the applicant show that in the

Multi-frequency plasma system according to FIG. 1, inter alia, by nonlinearities in the plasma P (for example

Saturation effects) mixed products from those in the plasma

introduced high-frequency power signals LSI, LS2, which also in an ideal impedance matching or adaptation of the first high-frequency generator 200 with respect to the basic frequency provided by him for the first

High frequency generator 200 is a "reflected" power represent. Information about the on the plasma P

reflected power and thus also over the mixing products are e.g. in the returning voltage wave Ur extending from the plasma P to the first

High frequency generator 200 propagates.

FIG. 2A schematically shows a power density spectrum over the frequency axis f according to preferred embodiments, from which the first high-frequency power signal at the first frequency f 1 (fundamental frequency) and the second

High frequency power signal emerge at the second frequency f2, wherein the second frequency is smaller than the first frequency fl, see. also the above already

described frequency values or frequency ranges for the first and second frequency. For example, the first frequency fl, that is the fundamental frequency, is about 13.56 MHz, and the second frequency f2 is about 100 kHz. Shown in FIG. 2A are in each case those power components LS1h, LSh2 which correspond to voltage waves propagating from the first high-frequency generator 200 (frequency f1) or from the second high-frequency generator 300 (frequency f2) to the plasma P or the plasma chamber PC.

FIG. 2B, in contrast, shows schematically

Power density spectrum for power components of the respective signals, each returning from the plasma P toward the first high frequency generator 200

Voltage waves Ur (Fig. 1) correspond. It can be seen from FIG. 2B that with respect to the fundamental frequency f1 a

There is a mismatch because a share of a

returning voltage wave at the fundamental frequency fl has a non-zero value. From FIG. 2B, however, it can also be seen that from the plasma P to the first High-frequency generator 200 mixing products of the fundamental frequency fl are conducted at the second frequency f2, cf. the

Summation frequencies fs_l, fs_2, fs_3 and difference frequencies fd_l, fd_2, fd_3 as they arise in the plasma P by electrical mixing of the two high frequency power signals LSI, LS2 (mixed products).

The sum frequencies can be determined as a function of the equation fs_n = fl + n * f2, and the difference frequencies can be determined as a function of the equation fd_n = fl -n * f2, where fs_n is an n-th sum frequency, where fl is the first frequency, where n is a natural number greater than zero, where the multiplication operator is where f2 is the second

Frequency is, and where fd_n is an n-th difference frequency. Accordingly, in FIG. 2B, sum frequencies and

Difference frequencies for n = 1, 2, 3 shown.

Figure 2C schematically shows a power density spectrum in the case of an optimum match with respect to the fundamental frequency f 1, as can be obtained using the principle of the embodiments. Only the

Power densities of the sum frequencies and difference frequencies, ie the mixed products, which form a first sideband SB1 and a second sideband SB2, non-disappearing

Amplitude values on. Even with perfect matching with respect to the fundamental frequency f1, these mixed products represent electrical power reflected (or generated) by the plasma P, which can load the first high-frequency generator 200 connected to the plasma chamber PC via the high-frequency line 210. These mixed products or sidebands

represent a good excitation of the plasma P, are therefore not undesirable per se, but may also burden the first high frequency generator 200, albeit in a different way reflected electric power at the fundamental frequency f. This may be considered in further preferred embodiments, which are described below with reference to FIG. 13, for example, in controlling the operation of the first high frequency generator 200, the reflected electric power at the fundamental frequency f and the reflected electrical power of the mixed products or sidebands according to their actual influence or

Effect, e.g. generation of undesired heat losses and / or overvoltages in the first high frequency generator 200.

In preferred embodiments, cf. For this purpose, also FIG. 1 and FIG. 3A, a device 100 or 100a is provided, which is designed to determine a first quantity G1 which characterizes a power reflected by the plasma P in the range of the first frequency f1, ie the fundamental frequency determine a second quantity G2 which characterizes a power reflected by the plasma P in a first frequency range, wherein the first frequency range is a

predefinable number of sum frequencies fs_l, fs_2, fs_3 (FIG. 2B) and / or difference frequencies fd_l, fd_2, fd_3

(Mixed products) from the first frequency fl and a

has integer multiples of the second frequency f2.

The principle according to the embodiments allows

advantageous, between a reflected power from the plasma P in the range of the first frequency fl, ie

Fundamental frequency, and one of the plasma P reflected

Power in the said first frequency range

Mixed products, for example, the first sideband SB1 and the second sideband SB2 according to FIG. 2C. As can be seen, the first frequency range may also comprise a plurality of subfrequency ranges which are not necessarily directly adjacent one another, as in the present case by the two sidebands SB1, SB2

are characterized. In particular, the fundamental frequency fl is not included in the first frequency range.

In other words, the first quantity Gl (FIG. 3A) represents a reflected power of the plasma P (FIG. 1)

Area of the fundamental frequency fl, in particular excluding the range of the likewise occurring or to be expected sidebands SB1, SB2, and the second size G2 represents a reflected power of the plasma P at least a portion of said mixed products. By determining the first and second quantities Gl, G2, an operation of the plasma P of a multi-frequency system can be characterized in a more precise manner and

be evaluated, and optionally an operation of the

High frequency generator 200 depending on the first and / or second size Gl, G2 are influenced, which should be indicated by the arrow A2.

For example, in further preferred embodiments for an assessment of the match ("match condition"), the generator impedance of the first radio-frequency generator 200 to the load impedance (ie, the impedance of the plasma P or the system comprising the plasma P and the optional matching network 220) with respect to the fundamental frequency fl only the reflected fundamental wave are considered, that is to say the proportion of the reflected power at the fundamental frequency f1. In other words, in preferred embodiments, the first variable G1 can be evaluated for the purpose of assessing the match condition.

For example, then can be on an optimal impedance or

Power adjustment of the first high-frequency generator 200 on the load impedance with respect to the fundamental frequency fl are closed when the first quantity Gl is a predeterminable first

Threshold falls below, preferably to zero.

At the same time, the second variable G2 can advantageously be used to judge an excitation of the plasma P.

In preferred embodiments, the apparatus 100, cf. FIG. 1, may have the first and / or second quantities Gl, G2 as a function of at least one operating variable of the

Detect multi-frequency plasma system, which rests for example on the high-frequency line 210 and thus

can be determined metrologically, compare the block arrow Al. Particularly preferably, the device 100a (FIG. 3A) is designed to determine the first variable G1 and / or the second variable G2 in dependence on a first signal sl, which is one from the plasma P (FIG. 1) to the first

High frequency generator 200 reflected, ie returning, voltage wave Ur characterizes.

FIG. 4 shows schematically a simplified block diagram of a further embodiment. It can be seen that in the present case an adaptation network 320 is also associated with the second high-frequency generator 300. Between the first high frequency generator 200 and its optional

Matching network 220, a directional coupler 230 is provided, which provides a first signal sl, that of the plasma P (FIG. 1) to the first high-frequency generator 200th

reflected voltage wave Ur characterizes. Instead of a directional coupler 230, in other embodiments, a voltage / current extraction ("Vl-sample", not shown) may be provided and the first signal sl thereof

supplied voltage and current signals are derived. The first signal sl is filtered by means of an input filter 102, in particular low-pass filtering, whereby a filtered signal sl 'is obtained which is transformed by means of an analog-to-digital converter (ADC) 104 into a time- and value-discrete digital signal sl''. The input filter 102 is preferably matched to the bandwidth of the ADC 104.

The digital signal sl '' is subjected to a down conversion, preferably by mixing, in particular by multiplication, with a local oscillator signal LO, whereby a second signal s2 is obtained. The second signal s2 is preferably on

(digital) baseband signal (frequency of the

Local oscillator signal LO essentially corresponds to the

Fundamental frequency f1, ie deviations of up to 2%, in particular up to 1%, are tolerable), but in other embodiments may also be an intermediate frequency signal (frequency of the local oscillator signal LO is less than the fundamental frequency f1).

The device 100, 100a is further configured to be at least one first low-pass filtering with first

Limit frequency from the second signal s2 to derive a third signal s3. This is done in the present case by means of

Low pass filters 106, 108, wherein the first cutoff frequency of the first low pass filtering is less than or equal to the second frequency f2. It can thus be ensured that the third signal s3 has only signal components which coincide with the fundamental frequency fl transformed into the baseband

correspond, but not signal components of

Mixed products. In further embodiments, instead of the two low-pass filters 106, 108, a single

Low pass filter can be used with the second cutoff frequency to determine the third signal s3 from the second signal s2. The device 100, 100a is particularly preferably designed to determine the first quantity G1 (FIG. 3A) as a function of the third signal s3, for example by forming a square of the magnitude of the third signal s3: G1 = I s3 | ² .

The device 100, 100a is further configured to derive a fourth signal s4 from the second signal s2 by means of a second low-pass filtering with second cut-off frequency. In the present case, this takes place by means of the first low-pass filter 106, wherein the second cut-off frequency of the second low-pass filtering is greater than the second frequency, preferably greater than three times the second frequency. This can

ensure that the fourth signal s4 also

Having signal components which correspond to the mixing products at least first to third order. In addition, the fourth signal s4 has signal components which correspond to the fundamental frequency fl transformed into the baseband. In simple terms, it can be stated that the fourth signal s4 has information about a power reflected by the plasma P both at the fundamental frequency f1 and in the range of the sum frequencies or difference frequencies of the mixed products, whereas the third signal s3

Information about the power reflected by the plasma P at the fundamental frequency fl, but not in the range of

Has cumulative frequencies or difference frequencies of the mixed products.

In preferred embodiments, the functionality is as described above with respect to FIG

Components 102, 104, LO, 106, 108 at least partially integrated into the device 100, 100a. FIG. 5 schematically shows a further embodiment. As already described above and seen in FIG. 5, the first quantity Gl, which reflects a power reflected by the plasma P (FIG. 1) in the range of the first frequency f 1 (FIG. 2B), is expressed as the square of the magnitude of the third

Received signal s3.

Similarly, a third quantity G3 is obtained as the square of the magnitude of the fourth signal s4, with optionally additionally low-pass filtering by another

Low pass 109 takes place. This can be, especially for one

visual indication of the third variable G3, be expedient because amplitude values of the fourth signal s4 with the second

Frequency or integer multiples thereof may be modulated.

More preferably, the device 100, 100a is to

designed to determine the second size G2 in response to the fourth signal s4 and the first size Gl. As can be seen from FIG. 5, in further preferred embodiments

Embodiments e.g. the second quantity G2 can be determined as the difference between the third quantity G3 and the first quantity Gl: G2 = G3 - Eq. The subtraction takes place here by means of an unspecified adder or subtractor.

In further preferred embodiments, the

described above with reference to FIGS. 4, 5

Steps for example by means of hardware and / or software or a combination thereof.

In further preferred embodiments, the

Device 100, 100a, for example, at least iw the configuration 1000 shown in FIG. The configuration 1000 has a computing device 1010 such as a microcontroller and / or microprocessor

and / or a digital signal processor (DSP) and / or a programmable logic device (e.g., FPGA) and / or an application specific integrated circuit (ASIC) and a memory device 1020 for at least temporary use

Storage of one or more computer programs PRG1, PRG2, .... At least one of the computer programs PRG1, PRG2 can be used to control an operation of the device 100, 100a, in particular for carrying out the method according to the

Embodiments, be provided. By way of example, the determination of at least one of the variables G1, G2, G3 can take place under

Control of one of the computer programs PRG1, PRG2 done. The memory device 1020 may preferably have a volatile one

Memory 1022 such as a random access memory ("RAM") and / or nonvolatile memory 1024 (e.g., read-only memory)

("ROM") and / or EEPROM, in particular flash EEPROM or the like).

Furthermore, the configuration 1000 may comprise a peripheral device 1030, which may comprise at least one filter device 1032 (also analogue filter device possible) executed at least partially in hardware and / or mixer device 1034 and / or ADC 1036 and / or data interface 1038. For example, in some embodiments, the filter device 1032 may implement the function of the input filter 102 of FIG. In further embodiments, the ADC 1036 may implement the function of the ADC 104 of FIG. In further embodiments, the

Mixing device 1034 according to Figure 17, the function of

Mixer according to Figure 4 realize, so for example. a

Frequency transformation of the signal sl '' in the baseband signal s2. In further embodiments, the data interface 1038 may be configured to output at least one size, such as the first and / or second and / or third quantities Gl, G2, G3, to an external unit (not shown). In the case of the external unit, according to another embodiment, for example, the first high-frequency generator 200 may be provided

and / or an external display device.

In further preferred embodiments, the

Configuration 1000 also have an optional display device 1040, with more preferably having multiple separate

Display units 1042, 1044, 1046 are provided,

For example, in the form of liquid crystal (LCD) displays or seven-segment displays or displays from the LED (light

emitting diode) or OLED (organic LED) type. Preferably, the first size Gl is output on the first display unit 1042, the second size G2 on the second display unit 1044, and the third size G3 on the third display unit 1046.

In further preferred embodiments, the

17 for implementing the function of the input filter 102 according to FIG. 4, and the ADC 1036 can transform the signal sl 'received at the output of the input filter 102 into the digital domain as already described, thus providing the signal sl' '. The further processing described above with reference to FIG. 4, in particular the determination of the signals s2, s3, s4, can be used in further preferred embodiments

For example, completely by the computing device 1010, in particular under the control of a corresponding

Computer program PRG1, as part of a digital

Signal processing done. The low-pass filters 106, 108 according to FIG. 4 can be implemented in the configuration 1000 according to FIG. 17, for example by digital FIR (finite impulse response) filters, which can be evaluated by the computer 1010 or corresponding computer programs.

In other embodiments, this also applies to the mixture with the local oscillator signal LO.

In further embodiments, it is also conceivable, instead of the order shown in Figure 4, a downward conversion by mixing with the local oscillator signal LO before the

Analog / digital conversion performed by the ADC 104. This advantageously allows a lower bandwidth ADC 104

be provided, for example, again in the form of the ADC 1036 according to the configuration 1000 of Figure 17. In these embodiments, it may be further provided that the

Down conversion is performed by the mixer device 1034 according to FIG. 17.

In further embodiments, it is also conceivable that o.g.

Filter steps in the analog domain, so no ADC is required.

In further embodiments, it is also conceivable to

Determining the second size G2 to use a band-pass filter (not shown), which in its filter curve on the

Fundamental frequency f 1 (FIG. 2B) contains a notch, and its lower and upper limit frequencies are chosen such that they cover the first frequency range, and therefore include the mixed products to be considered or their sum frequencies and difference frequencies. Alternatively, in other embodiments, the providence of two separate

Bandpass filter (not shown) for each one of

Sidebands SB1, SB2 conceivable. In further embodiments, it is also conceivable to provide individual filters for each interest sum frequency fs_l, fs_2, .. and / or difference frequency fd_l, fd_2, .. (FIG. 2B) or for corresponding frequency groups. At further

Embodiments are proposed according to a

Amplitude formation (e.g., absolute value or squaring)

with respect to sidebands characterizing signals a

Provide low-pass filtering, since the amplitude values

(Power values) of the sidebands with the second frequency f2 or multiples thereof may be modulated.

In further preferred embodiments, the device 100, 100a is configured to have a fourth size G4, cf. 5 as a function of the first quantity G1 and the third quantity G3, in particular as weighted sum of the first quantity G1 and the third size G3, the first size G1 being assigned a first weighting factor a, and the third size G3 a second weighting factor b is assigned. Thus, G4 = a * G1 + b * G3. The fourth variable G4 thereby characterizes an electric power reflected by the plasma P, a portion of which is reflected

Power in the range of the fundamental frequency fl is represented by the first quantity Gl, and wherein a portion of the reflected power comprising the fundamental frequency fl and the mixing products represented by the third size G3. By

corresponding selection of the first and second weighting factors a, b, the respective proportions can be weighted in a corresponding manner to form the fourth size G4. In further preferred embodiments, the fourth size G4

For example, for influencing generation of the first high-frequency power signal LSI by the first

High frequency generator 200, see Figure 1, used become. For this purpose, the device 100 can transmit the fourth variable G4 to the high-frequency generator 200, compare the dashed arrow A2 of FIG.

In further preferred embodiments, which are described below with reference to Figure 3B, is the

Device 100, 100a designed to determine a fifth size G5 as a function of the first size Gl and the second size G2, in particular as a weighted sum of the first size Gl and the second size G2, wherein the first size G1 is associated with a third weighting factor c , and wherein the fourth size G4 is assigned a fourth weighting factor d. Thus: G5 = c * G1 + d * G2. The fifth variable G5 thereby characterizes an electrical power reflected by the plasma P, a portion of which reflects

Power in the range of the fundamental frequency fl is represented by the first quantity Gl, and wherein a portion of the reflected power comprising the mixed products, but not the

Fundamental frequency fl, represented by the second quantity G2. By appropriate choice of the third and fourth

Weighting factors c, d, the respective proportions corresponding to the formation of the fifth size G5

be weighted. In further preferred embodiments, the fifth quantity G5 may be used, for example, to influence generation of the first high frequency power signal LSI by the first high frequency generator 200, cf. FIG. 1. For this purpose, the device 100 can transmit the fifth variable G5 to the high-frequency generator 200, compare the dashed arrow A2 of Figure 1.

In further preferred embodiments, the device 100, 100a is configured to output and / or transmit at least one of the following quantities to an external unit 200 an optional display device 110 (FIG. 1): the first size G1, the second size G2, the third size G3, the fourth size G4, the fifth size G5. The output of one or more of the mentioned quantities G1,..., G5 can be effected, for example, to the first high-frequency generator 200 (compare the arrow A2 from FIG. 1), which in further preferred embodiments

Embodiments, for example, its operation or the

Generation of the first high frequency power signal LSI in

Dependence on the quantities issued to it can influence.

In further preferred embodiments, the

Device 100 via a (separate) display device 110 for outputting at least one of the mentioned quantities Gl, .., G5.

As a result, the corresponding output variables are visually perceptible, for example by a user of

Device 100 or the plasma system. In this way, the user advantageously receives information about an operation of the plasma P, in particular about electrical power reflected from the plasma, advantageously between reflected power in the range of the fundamental frequency f.sub.f (first variable G1) and reflected power in the region of the mixed products or

Sidebands (second size G2) can be differentiated.

FIG. 5 indicates this possibility for visual output by way of the display devices 110a, 110b, 110c which are shown by way of example.

FIG. 6 shows schematically a spectral representation of

High frequency power signals according to another

Embodiment. Shown are power densities of a returning from the plasma P voltage wave Ur (Fig. 1) at the fundamental frequency fl and the second frequency f2, as well as in Figure 6 for reasons of clarity not closer

designated mixed products comprising sum frequencies or Difference frequencies from the fundamental frequency fl and the second frequency f2 around the fundamental frequency fl around. In further preferred embodiments, filtering (analog or digital) by means of a first filter curve FC1 is proposed in order to determine a measure of the power reflected by the plasma P in the range of the fundamental frequency fl, and filtering (analog or digital) by means of a second filter curve FC2 to give a measure of the power reflected by the plasma P in the range of the fundamental frequency fl and the mixing products

determine. A measure of the reflected from the plasma

Performance alone in the field of mixed products (ie without

Shares the fundamental frequency fl), for example, from a difference of the filter curves FC1, FC2 obtained

Signals are detected. In the embodiments described above with reference to Figure 6 is a

Transformation into another frequency range like

for example, the baseband area or a

Intermediate frequency range not required.

FIG. 7 shows schematically a measuring technique

Spectral representation of a returning from the plasma P voltage wave according to an embodiment over a

Frequency axis f '. While a power density in the

Fundamental frequency f1 is comparatively small, proportions of the sidebands SB1 ', SB2' corresponding to the mixing products of the fundamental frequency f1 and the second frequency f2 have comparatively high power density values.

FIG. 8 shows schematically a time course of a

Impedance of the plasma P according to an embodiment,

shown as trajectory TI in a Smith chart. If an optional matching network 220 (FIG. 1) is present, the trajectory TI corresponds to the time course of the resulting impedance of the plasma and the

Adaptation network 220, ie the first

Line portion 210a in Figure 1 considered to the right. It can be seen from Figure 8 that no complete

Power adjustment to the impedance of the first

High frequency generator 200 consists. Rather, both phase and magnitude of the impedance vary in time, which is particularly due to the mixing products.

Therefore, in further preferred embodiments

be provided that the device 100, 100a thereto

is formed, an impedance of the plasma P (or a resulting impedance of the components plasma P and

Matching network 220), in particular the

temporal course of the impedance. This may provide information about possibly for the high frequency generator 200

critical operating conditions are obtained by

different phase values of the impedance can be characterized.

Hereinafter, further preferred embodiments will be described in terms of a reduced stress effect by electric power reflected at the plasma P in the region of

Sidebands SB1, SB2 (Figure 2C) at the first

High frequency generator 200 described.

In some embodiments, if the load impedance (eg, resulting impedance of the plasma P and the optional matching network 220 (FIG. 1)) is not matched to the impedance of the first high frequency generator 200, there is a partial or complete reflection of the high frequency (RF) power. This is the case, for example, if the load impedance of the "Matchbox 220 plus plasma chamber PC or plasma P" system is not the same Generator impedance of eg 50 ohms corresponds. This can be done, for example, by incorrect setting of the Matchbox 220 and / or the

Fundamental frequency fl of the output from the high-frequency generator 200 high-frequency power signal LSI and / or done by a change in the plasma P. In the Smith chart this load impedance is e.g. represented by a point outside the center (= no reflection,

Load impedance equals generator impedance).

According to investigations by the Applicant, depending on the phase position of the reflected voltage wave Ur (FIG. 1), the stress for the first high-frequency generator 200 due to reflected electrical power has different effects on different components of the high-frequency generator 200 compared to a leading voltage wave Ui (FIG. 1). While at a location of the impedance of the load in certain areas of the Smith chart components of the first

If radio-frequency generator 200 is capable of taking thermal damage, it may be that with a position of the impedance in other areas of the Smith chart, a gain element (e.g.

Transistor) of the output stage (not shown) is destroyed by improper switching (e.g., inductive or capacitive switching) and / or by voltage overshoot. This can also be the case in other embodiments

A 3 dB quadrature coupler generator in which two RF sources are combined in the 3 dB quadrature coupler.

Has e.g. in other embodiments, the reflected

Voltage wave Ur not the same frequency as the leading fundamental wave Ui, this corresponds to an ongoing

Phase shift. The impedance of such a

reflected voltage wave Ur, does not represent a fixed point in the Smith chart, but one constantly on a circle moving point whose diameter is the strength of the reflected voltage wave Ur and its

Rotation frequency corresponds to a frequency offset of the reflected voltage wave Ur to the fundamental wave. A higher frequency (greater than the fundamental frequency fl, see upper sideband SB2 of Fig. 2C) corresponds to a continuous one

Phase shift to larger angles and thus a counterclockwise point, a lower frequency (smaller of the fundamental frequency fl, see lower sideband SB2 of Fig. 2C) a clockwise running point. At two mirror-image frequencies (e.g., first sum frequency fs_l and first difference frequency fd_l, see Fig. 2B) in the lower and upper sidebands, the circles overlap to a line on which the point in the Smith chart reciprocates. This is shown schematically on the basis of the trajectory T2 of the impedance according to FIG. 9.

If the portions of the returning voltage wave Ur are not the same size with respect to the two frequencies, the line opens to an ellipse, cf. the trajectory T3 of Fig. 10. An additional reflection on the fundamental frequency fl shifts the centroid of the line out of the center of the Smith chart, cf. The higher-order spectral components (e.g., second sum frequency fs_2 and / or second difference frequency fd_2, see Fig. 2B) may curve the line, cf. the trajectory T5 from FIG. 12.

Since portions of the sidebands SB1, SB2 on the reflected voltage wave Ur do not correspond to a fixed impedance, the first high-frequency generator 200 or its components are not permanently stressed by the reflected electrical power in the region of the sidebands, but "only" in time with the various frequency offsets , so Frequency differences between the respective sum frequency or difference frequency and the fundamental frequency fl. Therefore, in further preferred embodiments in the

Sidebands SB1, SB2 be allowed to have a higher reflected electrical power than at the fundamental frequency fl

Determining the first variable G 1 and the second variable G 2 according to the embodiments makes it possible for further

Embodiments advantageous a corresponding assessment, as to whether the side bands associated with reflected power exceeds a predetermined threshold.

For example, this can be checked in further embodiments for an inserted type of high-frequency generator 200 or for its components, in particular under

Evaluation of a determined during operation of the plasma system second size G2.

In further preferred embodiments it can be provided that - especially in the presence of

reflected electric power in the area of

Sidebands - certain value ranges for the impedance of the load should not be taken. In a representation of the time-varying impedance as a trajectory in a Smith chart, this corresponds, for example, to at least one area in the complex impedance plane represented by the Smith diagram, in which the trajectory or parts thereof are not allowed to lie.

Such an impedance region to be avoided is exemplarily denoted by the reference symbol IG1 in FIG

Clarification hatched. Although the instantaneous impedance of the plasma P lies only temporarily within the region IG1, compare the above explanations, it may be advantageous in further embodiments if the trajectory T3 is so is modified that at no time the current

Impedance of the plasma P lies in the area IG1.

In other preferred embodiments, this can

can be achieved, for example, by a phase shift, as it can be effected for example by the change in the electrical length of the high-frequency line 210. In some embodiments, for example, it may be provided to change the length of the radio-frequency line 210, in particular of the section 210a and / or the section 210b, in order to achieve the desired rotation of the trajectory T3 (FIG. 10), in particular with the aim of removing the trajectory T3 from that to get out of the reach of the IG1 Avoiding Area.

In further embodiments, alternatively or additionally, a phase shifter between the

Radio frequency generator 200 and the plasma P or the optional matching network 220 may be provided. Combinations of an adaptation of the line length and a dynamic phase rotation by means of phase shifter means are also conceivable in further preferred embodiments.

Both of the above measures (amendment of

Line length, phase shifter) each cause a phase shift, whereby the i.w. can be rotated about the origin in the Smith diagram by the influence of the sidebands SB1, SB2 resulting trajectory T3 of the impedance.

FIG. 13 schematically shows a simplified block diagram of a high-frequency generator 400 according to a preferred embodiment

Embodiment. The high-frequency generator 400 has a, preferably controllable, oscillator 410 (for example a voltage-controlled oscillator, VCO) for generating a High frequency signal s20 on and optionally one

Driver device 420, preferably as a controllable

Amplifier is formed, and which is adapted to amplify the high-frequency signal s20, whereby an amplified high-frequency signal s21 is obtained. Of the

High-frequency generator 400 also has a, preferably likewise controllable, power amplifier 430, which is designed to further amplify the output signal s21 of the driver device 420, as a result of which an output of the driver unit 420 is amplified

Power amplifier 430, a high frequency power signal LSI 'is obtained, which in preferred embodiments

For example, for excitation of the plasma P is usable, compare also the first high-frequency power signal LSI according to Figure 1.

Optionally, a directional coupler 440 is provided for the

Coupling of signals Al 'is formed, the

Information about an outgoing from the high frequency generator 400 outgoing voltage wave Ui 'and / or one of the plasma P (Fig. 1) to the high frequency generator 400 returning voltage wave Ur' included. The signals Al 'can be supplied to a device 100b, which preferably the

Functionality of the device 100 or 100a described above, and is therefore designed to determine the first size Gl and the second size G2. In further preferred embodiments, the device 100b is also designed to determine at least one of the following variables G3, G4, G5. The device 100b can also have at least approximately a configuration 1000, as has already been described above with reference to FIG. 17. In further preferred embodiments, the

High-frequency generator 400 configured to perform the generation of the high-frequency power signal LSI 'in response to at least two of the following variables: first size Gl, second size G2, third size G3, fourth size G4, fifth size G5, in particular by means of a first controller 402 as a function of at least two of said variables G1 to G5. This can cause an operation of the

High frequency generator 400 advantageously taking into account both reflected at the plasma P electric power in the range of the fundamental frequency fl and the plasma P reflected electrical power in the region of

Sidebands SB1, SB2 are executed or influenced.

In particular, an ideal impedance or power adjustment with respect to the fundamental frequency f1 can thereby be carried out particularly advantageously, so that the electric power reflected by the plasma P is therefore zero at the fundamental frequency f1.

In further preferred embodiments, the

High frequency generator 400 has a first control channel RI for at least one of the following quantities: first size G1, second size G2, third size G3, fourth size G4, fifth size G5, and a second control channel R2 for at least one of the following quantities: first size Eq , second size G2, third size G3, fourth size G4, fifth size G5. On

optional third control channel is also conceivable and indicated in Figure 13 by the arrow R3. In other words, in further preferred embodiments, at least one, preferably also several, of the variables G1,..., G5 can be used to influence at least one component 410, 420, 430 of the high-frequency generator 400. In further preferred embodiments, for controlling the high-frequency generator 400 in dependence on the electric power reflected on the plasma P or the load, the proportions of the fundamental frequency f1 and the sidebands SB1, SB2 on the total reflected electrical power

be weighted differently. For example, the sidebands SB1, SB2 have only half the stress effect like the

Fundamental frequency fl to the high-frequency generator 400, then the control must be set to Pr total = Prfundamental + 0.5 * Prsideband, where Prgesamt corresponds to, for example, the fifth size G5, where Prfundamental for example, the first size corresponds to Gl, Prsideband example, the second size G2 corresponds s. also the description of FIG. 3B. In the present case, therefore, the value 1 is used as the third weighting factor c, and the value 0.5 is used as the fourth weighting factor d. Other values for the weighting factors are also conceivable in further preferred embodiments and may be e.g. also depending on circuit components of the high frequency generator 400, e.g. a transistor (not shown) of the power amplifier 430, e.g. depending on the dielectric strength of the transistor, etc.

Figure 14 shows schematically a simplified block diagram of a high frequency generator 400a according to another

Embodiment. The high frequency generator 400a may

For example, have a structure comparable to the high-frequency generator 400 according to Figure 13 and be adapted to output a high-frequency power signal LSI ''. As can be seen from FIG. 14, the radio-frequency generator 400a is assigned a phase shifter 404 which effects a predefinable phase shift of the high-frequency power signal LSI ", as a result of which the phase-shifted current High frequency power signal LSI '''is obtained, which, for example, the plasma P (Figure 1) can be fed. The

Phase shifter 404 may alternatively or in addition to a change in the line length of a

High frequency power signal LSI '' leading

High-frequency line can be used to influence a trajectory of the impedance, cf. also the above under

Referring to Fig. 10 made statements.

FIG. 15 schematically shows a simplified flowchart of a method according to one embodiment. In a first step 500, the device 100 (FIG. 1) determines a first quantity Gl (FIG. 3A) which is one of the plasma P (FIG. 1).

reflected power in the range of the first frequency fl characterized. In step 502, the device 100 determines a second quantity G2 that characterizes a power reflected by the plasma P in the first frequency range, the first frequency range being that described above

predeterminable number of sum frequencies fs_l, fs_2, fs_3 and / or difference frequencies fd_l, fd_2, fd_3 (FIG. 2B) from the first frequency fl and an integer multiple of the second frequency f2. In some embodiments, steps 500, 502 may also be performed in a different order and / or at least partially overlapping in time.

In an optional step 510, the device 100 determines the third variable G3 a) as the sum of the first variable G 1 and the second variable G 2 and / or b) as a function of the fourth

Signal s4, s. FIG. 4. Optionally, in step 510, further variables can also be determined or derived from the already determined variables G1, G2, G3, for example the fourth variable G4 (FIG. 5) and / or the fifth variable G5 (FIG. 3B), and / or other variables derivable therefrom.

In a further step 520, which is also optional, the device 100 gives at least one of the quantities G1 to G5 to an external unit, e.g. the first high-frequency generator 200, from. Alternatively or additionally, the device 100 can at least one of the sizes G1 to G5 via a

Display device 110 (Figure 1) so that it is visually perceptible by a person. This advantageously allows control of the operation of the plasma system or of the first high-frequency generator 200.

FIG. 16 schematically shows a simplified block diagram of a further embodiment in which, in addition to that described above with reference to FIG

Configuration, taking into account the running towards the plasma P voltage wave Ui. For this purpose, a signal sl0 is provided by means of the directional coupler 230, which characterizes the voltage wave Ui passing to the plasma P.

The signal sl0 is filtered by means of a further input filter 101, in particular low-pass filtering, whereby a low-pass filtered signal sl0 'is obtained, which is transformed by means of an analog-to-digital converter (ADC) 103 into a time- and value-discrete digital signal sl0' ' , The further input filter 101 is preferably adapted to the bandwidth of the ADC 103.

The digital signal sl0 '' becomes a down conversion

subjected, preferably by mixing, in particular by means of multiplication, with the local oscillator signal LO, whereby a further signal sl2 is obtained. The signal sl2 is

prefers a (digital) baseband signal (frequency of the Local oscillator signal LO corresponds to iw the fundamental frequency fl), but in other embodiments also a

Be intermediate frequency signal (frequency of the

Local oscillator signal LO is smaller than the fundamental frequency fl) ·

With knowledge of the complex-valued baseband signals s2, sl2, the (i.d.R.) also complex impedance of the load (plasma P or combination of plasma P and optional adaptation network 220 (FIG. 1)) can advantageously be determined.

In further preferred embodiments, the device 100, 100a, 100b is designed to additionally determine the fourth variable G4 and / or the fifth variable G5 as a function of the impedance of the load. In particular, for example, weighting factors a, b, c, d used in determining the fourth variable G4 and / or the fifth variable G5 may be given in

Dependence of the impedance of the load, e.g. depending on a time average of the impedance or a phase,

Preferably, taking into account the location of the trajectory in the Smith chart, formed or changed.

The principle according to the embodiments allows an improved power adjustment with respect to the fundamental frequency, especially in multi-frequency plasma systems and a precise characterization of an excitation of the plasma P. Furthermore, the principle according to the embodiments, a load of the first high frequency generator 200 by reflected power in the region of the sidebands SB1 To determine SB2 accurately and reduce it if necessary.

Further preferred embodiments relate to a use of a device and / or a method according to the embodiments for the transmission of the first variable Gl and the second size G2 to a display device and / or to a machine-readable interface for distinguishable

Presentation and / or processing of the two quantities Gl, G2.

High frequency generator 200, 400, 400a, wherein for the control of the first size Gl and the second size G2, each with different weighting factors not equal to zero are included in the scheme.

Impedanzanpassungsvorrichtung, in particular a

Adaptation network 220, wherein for the scheme, the first

Size G1 and the second size G2, each with different weighting factors, are included in the control, in particular the first quantity G1 having an absolute value

larger weighting factor than the second size G2.

Claims

claims

1. Device (100, 100a, 100b) for determining an electrical power reflected from a plasma (P), the plasma (P) having a first high-frequency power signal (LSI) having a first frequency (fl) and at least one at least one second frequency (f2), the second frequency (f2) being less than the first frequency (fl), the device (100; 100a; 100b) being designed to

to determine (500) a first quantity (Gl) which characterizes a power reflected by the plasma (P) in the range of the first frequency (fl),

to determine (502) a second quantity (G2) characterizing a power reflected from the plasma (P) in a first frequency range, the first one

Frequency range a predetermined number of

Sum frequencies (fs_l, fs_2, fs_3) and / or

Differential frequencies (fd_l, fd_2, fd_3) from the first frequency (fl) and an integer multiple of the second frequency (f2) and has

- between the power reflected by the plasma (P) in the

Range of the first frequency (fl), and the reflected power from the plasma (P) in said first

Differentiate frequency range.

The apparatus (100, 100a, 100b) of claim 1, wherein the

Sum frequencies (fs_l, fs_2, fs_3) depending on the equation fs_n = fl + n * f2 can be determined, and / or wherein the difference frequencies (fd 1, fd_2, fd 3) in Dependency of the equation fd_n = fl - n * f2 are determinable, where fs_n is an n-th sum frequency, where fl is the first frequency (fl), where n is a natural number greater than zero, where the multiplication operator, where f2 is the second Frequency (f2), and where fd_n is an nth difference frequency.

3. Device (100, 100a, 100b) according to at least one of

preceding claims, wherein the first frequency (fl) is between about 10 MHz, megahertz, and about 190 MHz.

4. Device (100, 100a, 100b) according to at least one of

preceding claims, wherein the second frequency (f2) is between about 10 kHz, kilohertz, and about 2.3 MHz.

5. Device (100, 100a, 100b) according to at least one of

preceding claims, wherein the device (100; 100a; 100b) is adapted to the first size (G1) and / or the second size (G2) in dependence on a first one

Determine signal (sl) that is one of the plasma (P) to a first high frequency power signal (LSI)

providing the first high-frequency generator (200; 400) reflected voltage wave (Ur) characterized.

6. Apparatus (100, 100a, 100b) according to claim 5, wherein the

Device (100; 100a; 100b) is adapted to transform the first signal (sl) or a signal (sl ', sl' ') derived therefrom by a down conversion into a second signal (s2), wherein in particular the second signal (S1) s2) is a baseband signal.

The apparatus (100, 100a, 100b) of claim 6, wherein the

Device (100; 100a; 100b) is designed to generate the first signal (sl) or a signal (sl 'derived therefrom, sl sl '') with a local oscillator signal (LO) to obtain the second signal (s2).

8. Device (100, 100a, 100b) according to at least one of

Claims 6 to 7, wherein the device (100; 100a; 100b) is adapted to at least a first

Low-pass filtering with the first cutoff frequency from the second signal (s2) to derive a third signal (s3), wherein in particular the device (100; 100a; 100b) thereto

is designed to determine the first variable (G1) as a function of the third signal (s3).

The apparatus (100; 100a; 100b) of claim 8, wherein the

first cutoff frequency is less than or approximately equal to the second frequency (f2), preferably smaller than the second frequency (f2).

10. Device (100; 100a; 100b) according to at least one of claims 6 to 9, wherein the device (100; 100a; 100b) is designed to be connected by means of a second

Low pass filtering with second cutoff frequency from the second signal (s2) to derive a fourth signal (s4), wherein in particular the device (100; 100a; 100b) thereto

is designed to determine the second variable (G2) as a function of the fourth signal (s4) and the first variable (G1).

The device (100; 100a; 100b) according to at least one of the preceding claims, wherein the device (100; 100a; 100b) is configured to have a third quantity (G3) a) as the sum of the first quantity (G1) and the second one Size (G2) and / or b) in dependence of the fourth signal (s4) to determine (510).

The apparatus (100; 100a; 100b) of claim 11, wherein the apparatus (100; 100a; 100b) is adapted to receive a fourth quantity (G4) in response to the first size (G1) and the third size (G3) in particular as the weighted sum of the first quantity (G1) and the third quantity (G3), wherein the first size (G1) is a first one

Weighting factor (a) is assigned, and wherein the third size (G3) is associated with a second weighting factor (b).

13. Device (100; 100a; 100b) according to at least one of the preceding claims, wherein the device (100; 100a; 100b) is designed to determine an impedance of the plasma (P), in particular a time profile of the plasma

Impedance of the plasma (P).

The apparatus (100; 100a; 100b) according to claim 13 and 12, wherein the device (100; 100a; 100b) is configured to have the fourth size (G4) and / or a fifth size (G5) additionally in dependence on the impedance of the plasma (P).

The apparatus (100; 100a; 100b) according to at least one of the preceding claims, wherein the apparatus (100; 100a; 100b) is adapted to output (520,100a) at least one of the following quantities to an external unit (200; ) and / or via a display device (110, 1040): the first size (G1), the second size (G2), the third size (G3), the fourth size (G4), a fifth Size (G5).

16. A method of operating a device (100; 100a;

100b) for determining one of a plasma (P)

reflected electrical power, wherein the plasma (P) having a first frequency (fl) having first High-frequency power signal (LSI) and at least one second high-frequency power signal (LS2) having at least one second frequency (f2), the second frequency (f2) being smaller than the first frequency (fl), wherein the device (100; 100a; 100b)

a first quantity (G1) is determined (500) which characterizes a power reflected by the plasma (P) in the range of the first frequency (fl),

a second quantity (G2) is determined (502), which is a power reflected from the plasma (P) in a first

Frequency domain characterized, with the first

Frequency range a predetermined number of

Sum frequencies (fs_l, fs_2, fs_3) and / or

between the power reflected by the plasma (P) in the range of the first frequency (fl) and the power reflected by the plasma (P) in the said first frequency

Frequency range can differentiate.

17. High frequency generator (200, 400, 400a) for generating

at least a first one a first frequency (fl)

having high-frequency power signal (LSI) with

at least one device (100; 100a; 100b)

at least one of claims 1 to 15.

The high frequency generator (200; 400; 400a) of claim 17, wherein the high frequency generator (200; 400; 400a) is adapted to generate the first one

High frequency power signal (LSI) by means of a first regulator (402) in response to at least two of

following sizes: first size (GI), second size (G2), third size (G3), fourth size (G4), fifth size (G5).

The high frequency generator (200; 400; 400a) of claim 18, wherein said high frequency generator (200; 400; 400a) has a first control channel for at least one of: first magnitude (G1), second magnitude (G2), third magnitude ( G3), fourth size (G4), fifth size (G5), and a second control channel for at least one of the following quantities: first size (G1), second size (G2), third size (G3), fourth size (G4 ), fifth size (G5).

20. Use of a device (100; 100a; 100b) according to

at least one of claims 1 to 15 and / or a method according to claim 16 for the transmission of the first size (G1) and the second size (G2) to one

Display device and / or to a machine-readable interface for distinguishable presentation and / or processing of the two variables (Gl, G2).

21. Use of a device (100; 100a; 100b) according to

at least one of claims 1 to 15 and / or a method according to at least one of claims 16, 20 for controlling a high-frequency generator (200; 400;

400a), wherein for the control the first variable (G1) and the second variable (G2), each with different weighting factors not equal to zero, are included in the control.

22. Use of a device (100; 100a; 100b) according to

at least one of claims 1 to 15 and / or a method according to at least one of claims 16, 20 to 21 for controlling an impedance matching device, in particular a matching network (220), wherein for the control of the first variable (G1) and the second variable (G2), each having different weighting factors, are included in the control, in particular the first variable (G1) having a larger magnitude

Weighting factor as the second size (G2).