Method for cleaning of CVD tools with in situ plasma sources using a f2 / ar / n2 or f2 / arf / n2 or f2 / ar / arf / n2 mixture with low ar or low arf or low ar / arf content

Abstract

The present invention relates to a method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, in particular a CVD chamber comprising an in-situ plasma source, comprising the step of cleaning the chamber with a cleaning gas, characterized in that the cleaning gas comprises a gas mixture M consisting essentially of F2 in an amount of 10 – 35% by volume, N2 in an amount of 50 – 75% by volume, and Ar and / or ArF in an amount of 5 – 15% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 add up to 100% by volume. Further, the present invention relates to a use of this cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing. Further, the present invention relates to a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of F2 in an amount of 27 – 32% by volume, N2 in an amount of 57 – 66% by volume, and Ar and / or ArF in an amount of 7 – 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

Description

[0001] Method for cleaning of CVD tools with in situ plasma sources using a Fg / Ar / Ng or Fg / ArF / Ng or Fg / Ar / ArF / Ng mixture with low Ar or low ArF or low Ar / ArF content

[0002] TECHNICAL FIELD

[0003] The present invention relates to the field of cleaning the surface of the chambers used for semiconductor, photovoltaic or flat panel manufacturing, more particularly CVD tools equipped with in-situ plasma sources. In particular, it relates a method using a F2 / Ar / N2 or F2 / ArF / N2 or F2 / Ar / ArF / N2 mixture with low Ar or low ArF or low Ar / ArF content as cleaning gas, and to the use of this mixture as cleaning agent.

[0004] TECHNICAL BACKGROUND

[0005] The present invention relates to a method for chamber cleaning using optimized gases comprising the three components F2, N2, and Ar; the three components F2, N2, and ArF; or the four components F2, N2, Ar and ArF. Treatment chambers are used, for example, in the semiconductor and photovoltaic industry to manufacture semiconductors, flat panel displays or photovoltaic elements. The manufacture generally comprises operations such as etching of a substrate or chemical vapor deposition on a substrate which, during the treatment, is typically located on a support provided inside the treatment chamber.

[0006] Chemical vapor deposition (CVD), physical vapor deposition (PVD) and atomic layer deposition (ALD) processes are widely used to produce semiconductors. The manufacture of semiconductors often involves chemical vapor deposition (CVD) on a substrate in a treatment chamber. The substrate, during the treatment, is typically located on a support provided inside the treatment chamber, and the treatment processes are often plasma-assisted. By means of such processes, for example, SiCh layers can be prepared from the so-called TEOS / Oxygen / Ozone CVD process wherein tetraethoxysilane is treated in a plasma apparatus in the presence of Oxygen, Ozone or can be deposited by thermal growth. Deposition of W, TiN and TaN are possible using PVD processes.

[0007] During operation of the respective apparatus, depositions not only occur on the substrates, but also on the inside walls and process kit surfaces of the reactor chamber. Regular removal of such deposits is desirable to obtain stable and repeatable deposition results with uniform surfaces at acceptable particle levels. The high requirements to sustain stable processes lead to frequent chamber cleaning.

[0008] Mainly, NF3 and other PFC (perfluorocarbons) gases were used for chamber cleaning application. As an environmentally friendly replacement solution, ternary mixtures of F2 / N2 / Ar have been developed. Fluorine gas has no global warming potential and may be used with relatively low energy consumption compared for example to NF3 or other PFC gases like e.g. C2F6.

[0009] First, compositions comprising F2 / N2 / Ar at 20 / 70 / 10% by volume have been developed. For instance, WO 2013 / 092770 discloses a ternary mixture F2 / N2 / Ar at 20 / 70 / 10% by volume for cleaning the inner surface of the tube of a LPCVD system (low-pressure chemical vapour deposition). A ternary mixture F2 / N2 / Ar at 20 / 70 / 10% by volume is also disclosed in WO 2015 / 173003. These documents focus on the use of the cleaning compositions in remote plasma sources. The disclosed mixtures have been developed to avoid the need of forming the plasma directly or in-situ in the reactor and / or cleaning chamber. Further, these compositions have the disadvantage of a rather low etching speed.

[0010] To increase etching rates, in further developments, the fluorine content has been increased, resulting in compositions comprising F2 / N2 / Ar at 30 / 40 / 30 % by volume. For instance, WO 2016 / 188718 discloses a ternary mixture F2 / N2 / Ar at 30 / 30 / 40% by volume, i.e. a mixture with a high argon content. It is demonstrated in Comparative Example 1c of this application (F2 / N2 / Ar 30 / 50 / 20% by volume) that reducing the Ar content is disadvantageous because this results in a decreased etching rate. However, the high Ar content in these compositions has the disadvantage that it causes damages on the surface of the CVD chamber. When ions are accelerated on the surface, this causes damages on the first layer of the surface. This problem happens especially when the gas and plasma source are in the same room, i.e. in tools with in-situ plasma sources. Thus, while ternary mixtures of F2 / N2 / Ar at 30 / 40 / 30 % by volume may be suitable for tools with remote plasma sources, the high Ar content in these mixtures is disadvantageous for tools with in-situ plasma sources.

[0011] For chemical vapor deposition, two different types of CVD instruments are typically used: CVD tools equipped with in-situ plasma sources and CVD tools equipped with remote plasma sources. In the in-situ tools, the plasma is generated directly within the CVD chamber, in close proximity to the substrate where the deposition occurs. Therefore, the plasma interacts directly with the substrate, providing high-energy ions, radicals, and other reactive species that facilitate the deposition process. In the remote tools, the plasma is generated in a separate chamber or region away from the substrate, and the reactive species are then transported to the CVD chamber. Therefore, the substrate is exposed to the reactive species without direct exposure to the high-energy plasma. This reduces potential damage to sensitive substrates. For plasma generation, an energy source for inducing plasma, such as radio frequency (RF) power, is provided within the processing chamber, forming a plasma to ionize the cleaning agent gas to enhance chemical reaction with the contamination on the chamber's interior surfaces.

[0012] The tools can be further divided into batch tools and single wafer tools. Batch tools can process multiple wafers simultaneously, often ranging from a few to several hundred wafers in a single run, whereas single wafer tools process one wafer at a time.

[0013] In in-situ plasma batch tools, there are two parts that need to be cleaned: (1) the shower heads, where most of the deposition layer is present and which are cleaned with higher pressure (HP), and (2) the corners, for which longer cleaning times are required and which are cleaned with lower pressure (LP). In-situ plasma single wafer tools do not have this (HP and LP) requirements but use the same pressure in the whole instrument. However, the high Ar content during the cleaning causes the same damaging effect on the surfaces.

[0014] It is desirable to perform the cleaning as fast as possible, and to clean as many wafers as possible before damaging occurs. Thus, there remains the need for cleaning compositions allowing for high etching rates without causing damages on the chamber surface. Additionally, it would be advantageous to increase the lifespan of the cleaning chamber and to lower the energy for plasma generation, such as RF power, needed during operation.

[0015] SUMMARY OF THE INVENTION

[0016] The present invention relates to a method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, comprising the step of cleaning the chamber with a cleaning gas, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of: F2 in an amount of 10 - 35% by volume,

[0017] N2 in an amount of 50 - 75% by volume, and

[0018] Ar and / or ArF in an amount of 5 - 15% by volume wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0019] In other words, the cleaning gas comprises a gas mixture M and optionally, further components. Within the gas mixture M, the amounts of F2, Ar and / or ArF, and N2 add up to 100% by volume, i.e. the gas mixture M consists of F2, Ar and / or ArF, and N2. It is understood that “consisting of F2, Ar and / or ArF, and W‘ encompasses the term “consisting essentially of F2, Ar and / or ArF, and N2“. Naturally, the gas mixture M can contain impurities, in particular impurities inevitably resulting from the production.

[0020] As the argon source, Ar, ArF or a mixture of Ar and ArF can be used. In the plasma, ArF decomposes into the active F species and Ar. It is understood that, when Ar is used as single argon source, the amount of flourine gas added to the gas mixture M is in the range of 10 - 35% by volume. If ArF or a mixture of Ar and ArF is used as argon source, it may be necessary to adjust the amount of flourine gas added to the gas mixture M. By this adjustment, it is ensured that the overall fluorine content during operation does not become excessively high which may result in damages of the equipment due to excessively active plasma. Thus, the amount of flourine gas added to the gas mixture M has to be adjusted such that the overall fluorine content during operation is not higher than the fluorine content during operation which is achieved when the mixture M comprises Ar as single argon source and 35% by volume F2. The skilled person knows how to determine by standard experiments and / or calculations how to adjust the F2 content to keep the overall maximum fluorine content in the desired range.

[0021] Further, the present invention relates to a use of a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0022] F2 in an amount of 10 - 35% by volume,

[0023] N2 in an amount of 50 - 75% by volume, and Ar and / or ArF in an amount of 5 - 15% by volume wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0024] Particularly, the present invention relates to a method and a use wherein the chamber is a CVD chamber comprising an in-situ plasma source.

[0025] Further, the present invention relates to a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0026] F2 in an amount of 27 - 32 by volume,

[0027] N2 in an amount of 57 - 66% by volume, and

[0028] Ar and / or ArF in an amount of 7 - 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0029] The inventive ternary or quaternary gas mixture is suitable to get a good etching efficiency while avoiding sputtering issues on the surface of the tool as well on the long time usage. It has the advantage to increase the lifetime of the tool compared to the ternary mixtures of the state of the art and allows operation at low RF power.

[0030] DETAILED DESCRIPTION OF THE INVENTION

[0031] Before the method of the invention will be described in detail, it is to be understood that this invention is not limited to specific method conditions described herein, since such conditions may, of course, vary.

[0032] It is also to be understood that the terminology used herein is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0033] As used herein, the singular forms "a", "an", and "the" include both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compound" means one compound or more than one compound. The terms "containing", "contains" and "contained of' as used herein are synonymous with "including", "includes" or " comprising", "comprises", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms “containing”, “contains”, "comprising", "comprises" and "comprised of as used herein comprise the terms "consisting of', "consists" and "consists of.

[0034] The term "consisting of encompasses the term "consisting essentially of. The term "consisting essentially of' means that specific further components can be present, namely those not materially affecting the essential characteristics of the gas mixture. Thus, as used herein, a gas mixture M consisting essentially of F2, N2 and Ar and / or ArF means that the gas mixture does not contain further components which materially affect the essential characteristics thereof. However, this term does not exclude the presence of impurities which are typically present in such gas mixtures.

[0035] Similarly, the terms “ternary mixture” and “quaternary mixture” mean that the three components (F2 / Ar / N2 or F2 / ArF / N2) or four components (F2 / Ar / ArF / N2) of the mixture are those compounds which affect the essential characteristics of the gas mixture. However, it does not exclude the presence of more than three or four components, respectively, provided that these further components are not materially affecting the essential characteristics of the gas mixture. In particular, the presence of impurities is not excluded. Thus, the term “ternary mixture” means that the mixtures "consists essentially of' the respective three components; and the term “quaternary mixture” means that the mixtures "consists essentially of' the respective four components.

[0036] Similarly, the term “the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume” means that the amounts of F2, Ar and / or ArF, and N2 together with any further components which not materially affect the essential characteristics of the gas mixture (e.g. impurities) add up to 100% by volume. In other words, the total amount of of F2, Ar and / or ArF, and N2 in the gas mixture can be slightly lower than 100% by volume due to the presence of minor amounts of further components, such as impurities.

[0037] Throughout this application, the term "about" is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value. As used herein, the term “average” refers to number average unless indicated otherwise.

[0038] As used herein, the terms “% by weight”, “wt.-%”, “weight percentage”, or “percentage by weight” are used interchangeably. The same applies to the terms “% by volume”, “vol.- %”, “vol. percentage”, or “percentage by volume”, or “% by mol”, “mol- %”, “mol percentage”, or “percentage by mol”.

[0039] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0040] All references cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings of all references herein specifically referred to are incorporated by reference.

[0041] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0042] In the following passages, different alternatives, embodiments and variants of the invention are defined in more detail. Each alternative and embodiment so defined may be combined with any other alternative and embodiment, and this for each variant unless clearly indicated to the contrary or clearly incompatible when the value range of a same parameter is disjoined. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0043] Furthermore, the particular features, structures or characteristics described in present description may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and from different embodiments, as would be understood by those in the art.

[0044] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0045] Figures

[0046] Figures 1 to 3 are REM pictures of the process kit surface after processing of 13,000 wafers in a batch tool with a mixture comprising F2 / N2 / Ar at 30 / 40 / 30 vol% (Example 1, Mixture B). The particles were identified as aluminum fluoride particles.

[0047] Figure 4 shows the results of EDX analysis at 5 kV of one of the particles shown in Figure 3. The particle was identified as aluminum fluoride particle.

[0048] Figure 5 shows the results of EDX analysis at 15 kV of one of the particles shown in Figure 3. The particle was identified as aluminum fluoride particle.

[0049] Figure 6 is a photograf of the cover plate (a) and the showerhead (b) after processing of 2,500 wafers in a single wafer tool with a mixture comprising F2 / N2 / Ar at 30 / 40 / 30 vol% (Example 2, Mixture B). The cover plate is black due to ion bombardment.

[0050] The inventive method

[0051] The present invention provides a method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, comprising the step of cleaning the chamber with a cleaning gas, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of F2 in an amount of 10 - 35% by volume, N2 in an amount of 50 - 75% by volume, and Ar and / or ArF in an amount of 5 - 15% by volume (wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume). Further, the present invention relates to a use of this cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing. The inventive method is suitable for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing. Preferably, the method is for cleaning the chamber of an apparatus used for semiconductor manufacturing or photovoltaic manufacturing. Similarly, the inventive use relates to the use of the cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, preferable for cleaning the chamber of an apparatus used for semiconductor or photovoltaic manufacturing.

[0052] A ternary mixture of F2 / N2 / Ar at 30 / 40 / 30 % by volume, which has been developed for cleaning the surface of the chambers of CVD tools equipped with remote plasma sources (WO 2016 / 188718), was tested for cleaning CVD tools equipped with in-situ plasma sources (see Examples below). We observed that, during the cleaning of the chambers, wherever the plasma sources were located, damages to the surface of the CVD chamber occured. This became strongly evident, in a way that the tool could not be used anymore, due to surface particles. After this occured, the process kit parts of the chamber needed to be refurbished.

[0053] We identified that the cause of the damages was the high Ar (30%) content. By replacing mixture of F2 / N2 / Ar at 30 / 40 / 30 % by volume with the inventive mixture, the sputtering problem was suppressed (even after 36 months no change on the surface were detected) while maintaining a suitable etch rate.

[0054] Further, a ternary mixture of F2 / N2 / Ar at 20 / 70 / 10% by volume, which has been developed for cleaning the surface of the chambers of CVD tools equipped with remote plasma sources (WO 2013 / 092770, WO 2015 / 173003), was tested for cleaning CVD tools equipped with in-situ plasma sources (see Examples below). We observed that the cleaning rate of the known ternary mixture is very low in comparison to the cleaning rate obtained for the inventive mixture.

[0055] During manufacturing, cleaning takes a considerable amount of time, for instance, 40% of time are used for deposition and 60% of time are used for cleaning. Thus, by increasing the etching speed and consequently, decreasing the cleaning time, the process becomes faster. Further, if it is possible to process more wafers before a damage on the chamber surface occurs, the lifespan of the chamber is increased. Preferably, the gas mixture M consists essentially of F2 in an amount of 20 - 35% by volume, N2 in an amount of 55 - 70% by volume, and Ar and / or ArF in an amount of 7 - 13% by volume. More preferably, the gas mixture M consists essentially of F2 in an amount of 27 - 32% by volume, N2 in an amount of 57 - 66% by volume, and Ar and / or ArF in an amount of 7 - 11% by volume. Preferably, the gas mixture M consists essentially of F2 in an amount of 31 - 32% by volume, N2 in an amount of 59 - 61% by volume, and Ar and / or ArF in an amount of 9 - 11% by volume. In each case, the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume. Especially suitable mixtures consist essentially of approximately 30% by volume of F2, approximately 60% by volume of N2 and approximately 10% by volume of Ar and / or ArF. Here, the term “approximately” preferably denotes a range of 30±0.5 % by volume for F2, 60±0.5 % by volume for N2, and 10±0.5 % by volume for Ar and / or ArF, wherein the amounts of F2, Ar and / or ArF, and N2 add up to 100% by volume. As outlined above, further components, such as impurities, can be present.

[0056] In a preferred embodiment, the present invention relates to a method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, comprising the step of cleaning the chamber with a cleaning gas, wherein the chamber comprises an in-situ plasma source, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0057] F2 in an amount of 10 - 35% by volume,

[0058] N2 in an amount of 50 - 75% by volume, and

[0059] Ar and / or ArF in an amount of 5 - 15% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0060] In contrast to F2 / N2 / Ar cleaning compositions of the prior art, as discussed in the Background section above, which have been developed for use in remote plasma sources, the inventive method is particularly suitable for in-situ plasma sources.

[0061] In another preferred embodiment, the present invention relates to a method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, comprising the step of cleaning the chamber with a cleaning gas, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0062] F2 in an amount of 27 - 32% by volume,

[0063] N2 in an amount of 57 - 66% by volume, and

[0064] Ar and / or ArF in an amount of 7 - 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0065] More preferably, the gas mixture M consists essentially of:

[0066] F2 in an amount of 31 - 32% by volume,

[0067] N2 in an amount of 59 - 61% by volume, and

[0068] Ar and / or ArF in an amount of 9 - 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0069] The inventive method of this preferred embodiment (i.e. which uses a cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of F2 in an amount of 27 - 32% by volume, preferably 31 - 32% by volume; N2 in an amount of 57 - 66% by volume, preferably 59 - 61% by volume; and Ar and / or ArF in an amount of 7 - 11% by volume, preferably 9 - 11% by volume; wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume) is suitable for in-situ as well as remote plasma sources, and particularly suitable for in-situ plasma sources.

[0070] Further, the present invention relates to cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of F2 in an amount of 27 - 32% by volume, preferably 31 - 32% by volume; N2 in an amount of 57 - 66% by volume, preferably 59 - 61% by volume; and Ar and / or ArF in an amount of 7 - 11% by volume, preferably 9 - 11% by volume; wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume. This cleaning gas is suitable for use in apparatus comprising in-situ as well as remote plasma sources, and particularly suitable for in-situ plasma sources. When the fluorine content is above 35% by volume, there is a risk of burning due to the high oxidation power of fluorine gas. Therefore, for safety reasons, the maximum fluorine content should be not higher than 35% by volume. As outlined above, when ArF or a mixture of Ar and ArF is used as argon source, the amount of flourine gas added to the mixture M may be adjusted accordingly.

[0071] In the following, preferred features of the invention are disclosed. Unless indicated otherwise or obvious from the context, these features apply to any of the inventive methods and uses described in this application.

[0072] Preferably, the cleaning gas further comprises O2 or N2O. Diluting the cleaning gas with with O2 or N2O can enhance the efficiency of the cleaning process. The presence of oxygen and nitrous oxide can support the breaking down of contaminants and the conversion thereof into volatile compounds and allows to reduce the amount of toxic gases contained in the cleaning gas.

[0073] Preferably, for a batch tool, the gas flow of the inventive gas mixture M is in the range of 600 to 1200 ml / min, more preferably 700 to 1100 ml / min, more preferably 800 to 1000 ml / min.

[0074] Preferably, for a single wafer tool, the gas flow of the inventive gas mixture M is in the range of 400 to 1000 ml / min, more preferably 500 to 900 ml / min, more preferably 600 to 800 ml / min.

[0075] Preferably, for a batch tool, the gas flow of the diluting gas (O2 or N2O) is in the range of 300 to 500 ml / min, more preferably 350 to 450 ml / min.

[0076] Preferably, for a single wafer tool, the gas flow of the diluting gas (O2 or N2O) is in the range of 200 to 400 ml / min, more preferably 250 to 350 ml / min.

[0077] Preferably, the gas flow of the inventive gas mixture M is about 2 to 3 times the gas flow of the diluting gas. For instance, for a single wafer tool, a suitable combination is a gas flow of the inventive gas mixture M in the range of 600 to 800 ml / min, and a gas flow of the diluting gas in the range of 200 to 400 ml / min. For instance, for a batch tool, a suitable combination is a gas flow of the inventive gas mixture M in the range of 800 to 1000 ml / min and a gas flow of the diluting gas in the range of 300 to 500 ml / min.

[0078] Preferably, the inventive method and use relate to the cleaning of a CVD chamber, a PVD chamber or an ALD chamber, more preferably a CVD chamber. Preferably, the chamber comprises an in-situ plasma source. More preferably, the chamber is a CVD chamber comprising an in-situ plasma source.

[0079] In a preferred embodiment, the invention relates to use of a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, wherein the chamber is a CVD chamber, a PVD chamber or an ALD chamber comprising an in-situ plasma source, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0080] F2 in an amount of 10 - 35% by volume,

[0081] N2 in an amount of 50 - 75% by volume, and

[0082] Ar and / or ArF in an amount of 5 - 15% by volume wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0083] In contrast to the use of F2 / N2 / Ar cleaning compositions of the prior art, as discussed in the Background section above, which have been developed for use with chambers comprising remote plasma sources, the inventive use is particularly suitable for cleaning a CVD chamber, a PVD chamber or an ALD chamber comprising an in-situ plasma source. The term “the chamber is a CVD chamber, a PVD chamber or an ALD chamber comprising an in-situ plasma source” means that “the chamber is a CVD chamber comprising an in-situ plasma source, a PVD chamber comprising an in-situ plasma source or an ALD chamber comprising an in-situ plasma source”.

[0084] In another preferred embodiment, the present invention relates to use of a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:

[0085] F2 in an amount of 27 - 32% by volume,

[0086] N2 in an amount of 57 - 66% by volume, and

[0087] Ar and / or ArF in an amount of 7 - 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0088] More preferably, the gas mixture M consists essentially of: F2 in an amount of 31 - 32% by volume,

[0089] N2 in an amount of 59 - 61% by volume, and

[0090] Ar and / or ArF in an amount of 9 - 11% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

[0091] The inventive use of this preferred embodiment (i.e. which uses a cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of F2 in an amount of 27 - 32% by volume, preferably 31 - 32% by volume; N2 in an amount of 57 - 66% by volume, preferably 59 - 61% by volume; and Ar and / or ArF in an amount of 7 - 11% by volume, preferably 9 - 11% by volume; wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume) is suitable for the cleaning of chambers comprising an in-situ plasma source and of chambers comprising remote plasma sources, and particularly suitable for chambers comprising an in-situ plasma source.

[0092] By way of non limiting example, a suitable instrument for the inventive method is described for instance in US 6,277,235 Bl. The processing chamber of this instrument comprises a showerhead; a cleaning gas supply; a second gas supply; a chuck positioned below the showerhead; and a pumping port. The showerhead has a porous face plate. The chuck is coupled to the cleaning gas supply and the second gas supply to direct a flow of the cleaning gas into the processing chamber, wherein a portion of the cleaning gas flows into the showerhead through the face plate. The pumping port drains the cleaning gas out of the processing chamber via a vacuum pump. Further, the processing chamber is coupled to an RF power source, which produces an electromagnetic field within the chamber. The cleaning gas forms an ionizing plasma in the electromagnetic field and thus, the portion of the cleaning gas flowing through the face plate of the showerhead are cleaning gas ions. Further, the showerhead is coupled to a purge gas supply. The chuck, the showerhead, and the walls of the processing chamber are coupled to a temperature regulator.

[0093] Preferably, for a batch tool, cleaning is performed at a pressure in the range between 40 and 130 Pa, preferably between 45 and 110 Pa, more preferably between 50 and 100 Pa. Preferably, for a single wafer tool, cleaning is performed at a pressure in the range between 250 and 550 Pa, preferably between 300 and 500 Pa, more preferably between 350 and 450 Pa. The pressure affects the volume within the chamber that becomes a plasma during application of the energy source inducing plasma, e.g. RF power. A high pressure constrains the plasma to the area near the supply, and a low pressure permits the volume of the plasma to expand. The preferred pressure ranges allow an efficient plasma distribution.

[0094] Preferably, for a batch tool, the temperature in the chamber during cleaning lies in the range between 150 and 350°C, preferably 175 and 325°C, more preferably 200 and 300°C. Preferably, for a single wafer tool, the temperature in the chamber during cleaning lies in the range between 300 and 500°C, preferably 325 and 475°C, more preferably 350 and 450°C. Operating in this temperature range allows an effective cleaning without increasing the risk of damages to the equipment due to elevated temperatures.

[0095] During CVD, PVD or ALD processes, inorganic or organic contamination may occur in the chambers used. The term “chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing” preferably denotes the surface of parts inside the chamber, and it denotes especially the shower heads and the walls of the chamber. Further parts inside the chamber are, for example, construction material and lines inside the chamber, and pump conducts.

[0096] Preferably, the chamber is a CVD chamber comprising an in-situ plasma source. Plasma can be generated by applying a high frequency voltage between opposed electrodes or in a magnetron / SSR (Solid State Relais) which provides microwaves the frequency of which is to the upper range of radio frequencies. The electromagnetic waves heat up the gas phase inside the plasma reactor. Atoms with high reactivity are formed, e.g. F atoms which then etch matter away, forming volatile reaction products. The method of the invention is suitable to remove material deposited within the chamber, particularly on the exposed surfaces. This is achieved by reaction of the cleaning gas with the deposits resulting in the formation of volatile reaction products. For example, Si deposits, SiCh deposits or W deposits form gaseous SiF4 or gaseous WFe, respectively, when reaction with F2 contained in the inventive mixture.

[0097] Preferably, in the inventive method, materials deposited on the surface of the chamber are removed, wherein the deposited material is selected from the group, consisting of: • optionally doped silicon oxides, obtained by thermal decomposition of tetraethoxysilicate (e.g. plasma-enhanced decomposition of tetraethoxy silicate (PETEOS), high-density plasma enhanced decomposition of tetraethoxy silicate (HDPTEOS), or from low pressure decomposed tetraethoxysilicate (LPTEOS));

[0098] • optionally doped silicon oxides, obtained by decomposition of silanes in the presence of oxygen or by decomposition of tetraethoxy silane;

[0099] • optionally doped silicon nitrides, obtained by decomposition of silane;

[0100] • amorphous, microcrystalline and crystalline Si, SisN4, SiOxNywherein 0 < x < 3 and 0 < y < 4, SiCE, amorphous, microcrystalline and crystalline Si hydrides, TaN, TiN or W; preferably SiCE and / or SisN4, more preferably SiCE.

[0101] Optionally doped silicon oxides or silicon nitrides can contain e.g. boron or phosphates as dopants.

[0102] More preferably, the deposited material is selected from the group, consisting of:

[0103] • optionally doped silicon oxides, obtained by decomposition of silanes in the presence of oxygen, by decomposition of tetraethoxy silane or by thermal decomposition of tetraethoxy silicate; preferably SiCE obtained by thermal decomposition of tetraethoxy silicate, and

[0104] • optionally doped silicon nitrides, obtained by decomposition of silane; preferably SisN4, obtained by decomposition of silane, wherein the removal of optionally doped silicon oxides, obtained by thermal decomposition of tetraethoxy silicate, by decomposition of tetraethoxysilane or by decomposition of silanes in the presence of oxygen, is particularly preferred.

[0105] As explained above, the ternary or quaternary mixture M can contain impurities next to F2, N2 and Ar and / or ArF. Preferably, the amount of impurities is low. Preferably, purified F2, N2, Ar and ArF gas is used. These gases are commercially available or can be produced according to known methods. F2 for use in the present invention can be produced for example by heating suitable fluorometallates such as fluoronickel ate or manganese tetrafluoride. Preferably, fluorine is produced by electrolysis of a molten salt electrolyte, in particular a potassium fluoride / hydrogen fluoride electrolyte, most preferably KF.2HF. Preferably, the obtained molecular fluorine is further purified. Suitable purification operations include removal of particles, for example by filtering or absorption and removal of starting materials, in particular HF, for example by absorption, and impurities such as in particular CF4 and O2. Typically, the HF content in molecular fluorine used in the present invention is less than 10 ppm molar. Typically, the fluorine used in the present invention contains at least 0.1 molar ppm HF. The produced and preferably purified molecular fluorine can be supplied to the inventive method, for example, in a transportable container.

[0106] The mixture M can be formed in the reactor, or preferably, a mixture of fluorine, nitrogen and argon and / or argon fluoride is formed before introducing it into the reactor. If the gases are introduced in such a premixed form into the reactor, a homogenous mixture is provided throughout the reactor chamber. The individual gases can either be delivered separately by different lines, or they can be delivered in one line wherein they are premixed before entering the plasma chamber, or they can be provided premixed in the form of a ternary or quaternary mixture. Such a ternary or quaternary mixture can easily be prepared by condensing or pressing the desired amounts of fluorine, argon and / or argon fluoride, and nitrogen into a pressure bottle. It is also possible to provide a mixture of fluorine and nitrogen in one line, and argon and / or argon fluoride in an additional line. Preferably, F2, N2 and Ar and / or ArF are introduced into the chamber not separately, but as a premixed homogenous mixture. Thereby it is guaranteed that a preset ratio of fluorine, nitrogen and argon and / or argon fluoride is homogeneously provided throughout the reactor. Further gases contained in the cleaning gas next to the gas mixture M, particularly the diluting gas (O2 or N2O), can be added to the gas mixture M in a manner known to the skilled person.

[0107] Preferably, as energy source for inducing plasma, a RF power source is used, which produces an electromagnetic field within the chamber for plasma generation. The RF power source preferably applies a RF power between 500 and 1500 W, more preferably between 600 and 1200 W, more preferably between 600 and 900 W for single wafer tools. Preferably, for batch tools the RF power is between 1000 and 3500 W, more preferably between 1000 and 2000 W, more preferably between 1000 and 1500 W. A suitable method according to the invention comprises the following stages:

[0108] The first stage is the Ignition Stage, wherein the plasma is ignited. For instance, pure argon can be used as ignition gas. Preferably, the gas mixture according to the present invention is used to ignite the plasma source without admixing further amounts of argon into the mixture. Thus, the complete cleaning cycle can be performed with the inventive gas mixture without the need to switch between different gas mixtures for the individual steps.

[0109] The second stage is the Pre-clean Stage. In this stage, the cleaning gas generally contains less fluorine-containing gas. It may be performed if relative large amount of deposit is found in certain parts of the chamber. In order to prevent an over-heating of parts of the chamber, these large deposits are etched in this Preclean stage with a milder gas mixture with less fluorine.

[0110] The third stage is the Main Cleaning Stage, wherein the majority of the deposits are removed from the treatment chamber. Advantageously, the Main Cleaning Stage might be the longest stage in the cleaning process. It might also be the stage wherein the most cleaning gas is consumed.

[0111] In this application, if it is referred to “cleaning” or “during cleaning”, this comprises the Main Cleaning Stage, unless indicated otherwise.

[0112] The fourth stage is the Post-Cleaning Stage, which generally uses an etching gas with a lower fluorine concentration. In this stage, any residual deposits in more remote and less easily accessible parts of the chamber are being etched.

[0113] Preferably, the inventive gas mixture is used in at least one of the cleaning stages. More preferably, it is used in the Main Cleaning Stage.

[0114] In summary, the inventive method has inter alia the following advantages:

[0115] • Increased etching speed due to higher F2 content in comparison to a ternary mixture of F2 / N2 / Ar at 20 / 70 / 10% by volume.

[0116] • Less damages on chamber surface occur due to lower Ar content in comparison to a ternary mixture of F2 / N2 / Ar at 30 / 40 / 30 % by volume.

[0117] • Lifespan of the chamber is increased.

[0118] • System can be operated with lower energy, e.g. a lower RF power. EXAMPLES

[0119] Different ternary mixtures F2 / N2 / Ar were investigated for their efficacy to remove SiCh and SisN4 depositions from cleaning chambers in CVD tools with in-situ plasma sources. The cleaning rate for the different mixtures was compared and the appearance of the chamber surface was investigated via EDX.

[0120] General procedure

[0121] The gas mixture is introduced through the shower head and ignited by the in-situ plasma, which burns between shower head and cover plate (susceptor=wafer holder). The Ar ions are accelerated towards the surfaces of the cover plate and shower head. This leads to a sputtering effect and a subsequent physical / chemical reaction. The reaction is forming AIF3 and is seen on the pictures as black rough surface and detected via EDX (energy dispersive X-ray spectroscopy).

[0122] In the experiments, premixed F2 / Ar / N2 mixtures were used, which were stored in pressure bottles. In the examples, gas amounts are given as ml / min. In the literature, an alternative commonly used unit is “standard cubic centimeter” (seem), wherein 1 ml / min = 1 seem. Based on the concentration (in %vol) of the individual gas constituents comprised in the gas mixture, the gas flow of each component in ml / min can be calculated. For example, if the inventive method is performed with a gas flow of 900 ml / min of the inventive mixture, this corresponds to a gas flow of 270 ml / min F2, 540 ml / min N2, and 90 ml / min Ar.

[0123] Experiments were performed on a batch tool and on a single wafer tool. The processing chamber of these tools comprises a showerhead; a cleaning gas supply; a second gas supply; a chuck positioned below the showerhead; and a pumping port. The showerhead has a porous face plate. The chuck is coupled to the cleaning gas supply and the second gas supply to direct a flow of the cleaning gas into the processing chamber, wherein a portion of the cleaning gas flows into the showerhead through the face plate. The pumping port drains the cleaning gas out of the processing chamber via a vacuum pump. Further, the processing chamber is coupled to an RF power source, which produces an electromagnetic field within the chamber. The cleaning gas forms an ionizing plasma in the electromagnetic field and thus, the portion of the cleaning gas flowing through the face plate of the showerhead are cleaning gas ions. Further, the showerhead is coupled to a purge gas supply. The chuck, the showerhead, and the walls of the processing chamber are coupled to a temperature regulator.

[0124] EXAMPLE 1: Experiments on a batch tool

[0125] Experiments were performed on a batch tool.

[0126] Mixture A (Fi / Ni / Ar at 20 / 70 / 10 vol%), Comparative Example

[0127] The removal of TEOS-based SiCE deposition was performed under the following conditions:

[0128] Temperature 360°C

[0129] HP: Gas flow: 3300 ml / min Mixture A, 600 ml / min O2

[0130] RE 2000 W

[0131] 3.0 Torr, 525 mils spacing (fix)

[0132] LP: Gas flow: 2250 ml / min Mixture A, 600 ml / min O2

[0133] RF: 2000 W

[0134] 0.7 Torr

[0135] The removal of silane-based SisN4 deposition was performed under the following conditions:

[0136] Temperature 400°C

[0137] HP: Gas flow: 3000 ml / min Mixture A, 300 ml / min O2

[0138] RF: 2500 W

[0139] 2.7 Torr, 440 mils spacing (fix)

[0140] LP: Gas flow: 2250 ml / min Mixture A, 300 ml / min O2

[0141] RF: 2000 W

[0142] 0.7 Torr

[0143] Mixture B (Fi / Ni / Ar at 30 / 40 / 30 vol%), Comparative Example

[0144] The removal of TEOS-based SiO2 deposition was performed under the following conditions:

[0145] Temperature 360°C

[0146] HP: Gas flow: 2500 ml / min Mixture B, 1000 ml / min O2

[0147] RF: 3500 W

[0148] 3.0 Torr, 525 mils spacing (fix)

[0149] LP: Gas flow: 2500 ml / min Mixture B, 1000 ml / min O2 RF: 3500 W

[0150] 1.5 Torr

[0151] The process was stopped after 5,500 wafers in chamber 1 and after 13,000 wafers in chamber 2. Aluminum fluoride particles were found on the process kit due to ion bombardment, see Figures 1 to 5.

[0152] The removal of silane-based SisN4 deposition was performed under the following conditions:

[0153] Temperature 400°C

[0154] HP: Gas flow: 2200 ml / min Mixture B, 2000 ml / min O2

[0155] RF: 3500 W

[0156] 2.7 Torr, 440 mils spacing (fix)

[0157] LP: Gas flow: 2200 ml / min Mixture B, 1000 ml / min O2

[0158] RF: 3500 W

[0159] 0.7 Torr

[0160] The process was stopped after -8000 wafers. Al-straps were attacked by plasma, resulting in stress shift on deposited wafers.

[0161] Mixture C (Fi / Ni / Ar at 30 / 60 / 10 vol%) (according to the invention)

[0162] The removal of silane based SiCh deposition was performed under the following conditions:

[0163] Temperature 250°C

[0164] HP: Gas flow: 900 ml / min Mixture C, 400 ml / min N2O

[0165] RF: 1150 W

[0166] 0.7 Torr

[0167] LP: Gas flow: 900 ml / min Mixture C, 400 ml / min N2O

[0168] RF: 1300 W

[0169] 0.4 Torr

[0170] In comparison to the POR (process of records (SF6 / N2O clean)), the clean-rate by ep-time (endpoint time) is 390 s versus 400 s POR. This corresponds to a 462 nm / min clean rate for the inventive process versus 450 nm / min clean rate for POR.

[0171] The results of Example 1 are summarized in Table 1 below. EXAMPLE 2: Experiments on a single wafer tool

[0172] Mixture B and Mixture C were further investigated on a single wafer tool.

[0173] Mixture B (Fi / Ni / Ar at 30 / 40 / 30 vol%), Comparative Example

[0174] The removal of TEOS-based SiCE deposition was performed under the following conditions:

[0175] Temperature 400°C

[0176] Gas flow: 1300 ml / min Mixture B, 700 ml / min O2 RE 1800W

[0177] 5.5 Torr, 999 mils spacing

[0178] The process was stopped after 2,500 wafers. Heater cover plate (process kit part) was black due to ion bombardment, see Figure 6.

[0179] In comparison to the POR (process of records (C2F6 / O2 / NF3)), the clean-rate by ep-time is 35 s versus 41 s POR with C2F6 at 400°C. This corresponds to a 994 nm / min clean rate versus 859 nm / min clean rate for POR.

[0180] Mixture C (Fi / Ni / Ar at 30 / 60 / 10 vol%) (according to the invention):

[0181] The removal of TEOS-based SiO2 deposition was performed under the following conditions:

[0182] Temperature 400°C

[0183] Gas flow: 700 ml / min Mixture C, 300 ml / min O2

[0184] RF: 700W

[0185] 3.0 Torr

[0186] 999 mils spacing

[0187] In comparison to the POR (process of records (C2F6 / O2)), the clean-rate by ep- time is 51.2 s versus 53.0 s POR with C2F6 at 400°C. This corresponds to a 785 nm / min clean rate for the inventive process versus 758 nm / min clean rate for POR.

[0188] The results of Example 2 are summarized in Table 1 below. Table 1: Cleaning performance a) Process was stopped after 5,500 wafers in chamber 1 and after -13,000 wafers in chamber 2. b) Process was stopped after -8,000 wafers c) Process was stopped after 2,500 wafers

[0189] As can be seen in the above table, in Example 1, with Mixture B, the process had to be stopped due to damages on the heater cover plate. The process using the inventive mixture qualifies for a production of >6000 wafer between wet cleaning operation. Even after 36 months no change on the surface were detected. The cleaning rates for Mixtures A, B and C in Example 1 are not directly comparable since silane based SiCE deposition can be more easily removed than TEOS based SiCE deposition.

[0190] In Example 2, the cleaning rate for Mixture B is slightly better than for Mixture C, but the number of processed wafers is significantly lower. With Mixture B, the process had to be stopped early due to damages on the heater cover plate. The process using the inventive mixture qualifies for a production of >6000 wafer between wet cleaning operation. Even after 36 months no change on the surface were detected.

[0191] Both in Example 1 and in Example 2, the applied RF power is significantly lower for inventive Mixture C than for Mixtures A and B. This has the advantage that the lifespan of the equipment is extended, in comparison to a process using higher RF power, and that safe and consistent performance is ensured.

[0192] Running with lower RF -Power plus dilution of inventive Mixture C with O2 or N2O resulted in production qualification (after long term testing under production conditions =fully qualified). This did not work with Mixture B, where too much ion bombardment (sputtering of the heater cover) due to the high Ar content in Mixture B occurred.

[0193] Operation at lower RF power has the advantage that damages to the chamber materials are reduced due to the lower ion energies. Thus, the cleaning process is less damaging and safer than processes using high RF power, thereby extending the lifespan of the equipment and ensuring safe and consistent performance. For instance, the potential for damage to the tool is minimized due to the use of less energetic ions; the ionization process can be more easily controlled, leading to a more stable and uniform plasma; lower power is required; and safety is enhanced due to a reduced risk of overheating and arching.

[0194] Diluting the cleaning gas with with O2 or N2O can enhance the efficiency of the cleaning process. The presence of oxygen can support the breaking down of contaminants and the conversion thereof into volatile compounds and allows to reduce the amount of toxic gases contained in the cleaning gas. In Example 1, Mixture B was investigated for cleaning of SiCh deposition and of SisN4 deposition. In both cases, damages on the surface were observed for Mixture B. This data shows that it is the high Ar content of Mixture B and not the kind of deposition which is responsible for the damaging. Mixtures B and C were investigated both on a batch tool and on a single wafer tool. In both cases, damages on the surface were observed for Mixture B. This data shows that it is the high Ar content of Mixture B and not the kind of instrument which is responsible for the damaging.

[0195] Further, although the inventive method preferably refers to cleaning of SiCh depositions, the data show that results for SiCh cleaning can be transferred to Si3N4.

Claims

CLAIMS1. A method for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, comprising the step of cleaning the chamber with a cleaning gas, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:F2 in an amount of 10 - 35% by volume,N2 in an amount of 50 - 75% by volume, andAr and / or ArF in an amount of 5 - 15% by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

2. The method according to claim 1, wherein the chamber is a CVD chamber, a PVD chamber or an ALD chamber.

3. The method according to claim 1 or 2, wherein the chamber comprises an in-situ plasma source.

4. The method according to 3, wherein the chamber is a CVD chamber comprising an in-situ plasma source.

5. The method according to claim 3 or 4, wherein a RF power source is used as energy source for inducing plasma, and the RF power for plasma generation is for a batch tool, between 1000 and 3500 W, or for a single wafer tool, between 500 and 1500 W.

6. The method according to any of claims 1 to 5, wherein the method removes material deposited on the surface of the chamber, wherein the deposited material is selected from the group, consisting of:• optionally doped silicon oxides, obtained by thermal decomposition of tetraethoxysilicate;• optionally doped silicon oxides, obtained by decomposition of silanes in the presence of oxygen or by decomposition of tetraethoxy silane;• optionally doped silicon nitrides, obtained by decomposition of silane;• amorphous, microcrystalline and crystalline Si, SisN4, SiOxNywherein 0 < x < 3 and 0 < y < 4, SiCh, amorphous, microcrystalline and crystalline Si hydrides, TaN, TiN or W.

7. The method according to claim 6, wherein the deposited material is selected from the group, consisting of• optionally doped silicon oxides, obtained by decomposition of silanes in the presence of oxygen, by decomposition of tetraethoxy silane or by thermal decomposition of tetraethoxy silicate, and• optionally doped silicon nitrides, obtained by decomposition of silane.

8. The method according to any of claims 1 to 7, wherein the gas mixture M consists essentially of:F2 in an amount of 27 - 32%, preferably of 31 - 32%, by volume,N2 in an amount of 57 - 66%, preferably of 59 - 61%, by volume, andAr and / or ArF in an amount of 7 - 11%, preferably of 9 - 11%, by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

9. The method according to any of claims 1 to 8, wherein the pressure is for a batch tool, in the range between 40 and 130 Pa, or for a single wafer tool, in the range between 250 and 550 Pa.

10. The method according to any of claims 1 to 9, wherein the temperature in the chamber during cleaning lies for a batch tool, in the range between 150 and 350°C, or for a single wafer tool, in the range between 300 and 500°C.

11. Use of a cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized inthat the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:F2 in an amount of 10 - 35% by volume,N2 in an amount of 50 - 75% by volume, andAr and / or ArF in an amount of 5 - 15% by volume wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

12. The use according to claim 11, wherein the chamber is a CVD chamber, a PVD chamber or an ALD chamber comprising an in-situ plasma source.

13. The use according to claim 11 or 12, wherein the gas mixture M consists essentially of:F2 in an amount of 27 - 32%, preferably of 31 - 32%, by volume,N2 in an amount of 57 - 66%, preferably of 59 - 61%, by volume, andAr and / or ArF in an amount of 7 - 11%, preferably of 9 - 11%, by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

14. The method according to any of claims 1 to 10, or the use according to any of claims 11 to 13, wherein the cleaning gas further comprises O2 or N2O.

15. A cleaning gas for cleaning the chamber of an apparatus used for semiconductor, photovoltaic or flat panel manufacturing, characterized in that the cleaning gas comprises a gas mixture M, the gas mixture M consisting essentially of:F2 in an amount of 27 - 32%, preferably of 31 - 32%, by volume,N2 in an amount of 57 - 66%, preferably of 59 - 61%, by volume, andAr and / or ArF in an amount of 7 - 11%, preferably 9 - 11%, by volume, wherein the amounts of F2, Ar and / or ArF, and N2 in the gas mixture M add up to 100% by volume.

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