KR20140108347A - Etching process - Google Patents

Abstract

Fluorine and mixtures of inert gases such as nitrogen and / or argon can be used to etch semiconductors, solar panels and flat panels (TFT and LCD), and clean semiconductor surfaces and plasma chambers. Preferably, the fluorine is included in the amount of 15 to 25% by volume in the binary mixtures. The gas mixtures can be used as alternatives or drop-in for each of the mixtures containing NF ₃ and allow very flexible operation of the plasma apparatus. For example, a regulated device for NF ₃ / Ar mixtures can be operated with no further adjustment using fluorine and argon, optionally with nitrogen. If ternary mixtures of fluorine, nitrogen and argon are used, the fluorine content is preferably in the range of from 1 to 5% by volume.
[Index]
Etching, cleaning, fluorine, nitrogen, argon, inert gas, deposition

Description

Etching Process {ETCHING PROCESS}

The present invention relates to a method of etching a substrate using gases comprising F ₂ .

Methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD) are widely used in the manufacture of semiconductors. By this method, for example, a layer of SiO _x N _y (simply referred to as SiON) can be produced by a so-called TEOS / ozone CVD process, wherein tetraethoxysilane is treated in a plasma apparatus in the presence of ozone do. SiO ₂ can be deposited by thermal growth. Deposition of W, TiN and TaN is possible using the PVD method.

During operation of each device, deposition takes place not only in the substrate but also in the inner walls of the reactor chamber. Periodic removal of such a deposition is desirable to obtain stable and repeatable deposition results with a uniform surface at acceptable particle levels. High demands to maintain a stable process often cause the chamber to be cleaned. NF ₃ , known as the main cleaning gas, is somewhat expensive.

U.S. Patent Application No. 2003/0056388 discloses a cleaning gas for chamber cleaning comprising SF ₆ and F ₂ and / or NF ₃ . U.S. Patent No. 5,425,842 discloses a method of cleaning a chamber using F ₂ or a fluorine compound and an oxygen or oxygen compound. These gas mixtures can be used to remove polymeric fluorocarbon contaminants. In a similar manner, these contaminants on the semiconductor surface can be removed. Contaminants are often formed when etching semiconductors using fluorocarbons or hydrofluorocarbons, often mixed with hydrogen, such as CF ₄ , C ₂ F _6, and CHF ₃ as an etch gas in the plasma chamber.

NF ₃ is often used as an etching gas in semiconductor manufacturing. It can be used to etch the inorganic coating such as SiON, amorphous _{(amorphous) Si, SiO 2,} TiN, TaN or W (tungsten).

It was an object of the present invention to identify an effective etching gas composition as a chamber cleaning gas and for other purposes in the field of semiconductor fabrication that significantly reduces environmental destructive global warming emissions. It is a particular object of the present invention to identify etching gas compositions useful in etching inorganic materials, especially in the form of mixtures, which can be used to etch inorganic contaminants, particularly in the framework of chamber cleaning.

These and other objects of the invention are achieved by a method according to the claims.

The method according to the present invention can be used for etching semiconductor materials (e.g., reactive ion etching, simply: RIE), semiconductors, solar panels, and flat panels (Thin Film Transistors ), Liquid crystal display (Liquid Crystal Display, briefly: TFT / LCD application) and cleaning of the chamber for surface preparation and semiconductor manufacturing (TFT / LCD application); And at least one inert gas selected from the group consisting of nitrogen and Group 0 gases (He, Ar, Xe and Kr). In general, the fluorine content of the mixture is preferably from 1 to 35% by volume and more preferably from 15 to 25% by volume. In a particularly preferred embodiment, the content of fluorine is in the range of 18 to 22% by volume. The mixture can be formed in a reactor or, preferably, a mixture is formed before introducing a mixture of fluorine and an inert gas or gases into the reactor. If gas is introduced into the reactor in this premixed form, a homogeneous mixture is provided throughout the reactor chamber. When fluorine-containing mixtures are used in a drop-in manner for NF ₃ , the fluorine content may be lower. This is described below.

According to a preferred embodiment of the present invention, the gas mixture consists of fluorine and inert gases or inert gases, fluorine being within the range given above, and inert gases or gases remaining in up to 100 vol%. This gas mixture are an advantageously for etching a semiconductor material such as SiON, amorphous Si, SiO _2, TiN, TaN or W, or to clean the semiconductor surface, or contamination by inorganic materials, or organic materials such as those mentioned in the May be used to clean the chamber. As previously explained, this organic material may be formed when etching a semiconductor material using poly- or perfluorocarbon compounds. The treatment with the gas mixture can be carried out in the presence of plasma or plasma-free. In the latter case, the temperature is conveniently 400 占 폚 or higher, preferably higher than 450 占 폚 and up to 650 占 폚 or higher. The range having good results is 400 to 800 캜, preferably 400 to 650 캜, particularly 450 to 650 캜.

It has been found that mixtures of fluorine with one inert gas, for example mixtures of fluorine and argon or mixtures of fluorine and nitrogen, are highly effective for the purposes mentioned above. They can be used in CVD, PVD or ALD processes running on commercial devices. Some of these devices are tuned to operate with gases that are commonly used in the processes described above. For example, these devices can be adjusted to operate with a mixture of some inert gas and NF ₃ . If, instead, the apparatus is operated with mixtures of fluorine and each inert gas, the apparatus will be calibrated and no problems will occur. The fluorine and inert gases may be carried as a mixture, or may be carried separately from each other. In the following, for this embodiment, the term "drop-in" will be used. This term is for example running in the adjustment point of view of the device, and often a physical condition of the gas in the reactor, for a example, a method under substantially the same conditions in terms of pressure and temperature applied in the reactor typically NF ₃ / inert gas . In principle, the drop-in method involves a situation where the apparatus is operated alternately with NF ₃ / inert gas and F ₂ / inert gas. Preferably, the context in which the term "drop-in" is adjusted for the first NF ₃ / inert gas mixture, and the operation with permanently F ₂ / inert gas mixture apparatus which can be operated in the NF ₃ / inert gas mixture it means.

This aspect of the invention will be further described for a preferred embodiment that provides for the application of nitrogen, fluorine and argon in such a plasma apparatus.

Mixtures of fluorine and argon are excellent drop-in alternatives for mixtures including, for example, NF ₃ , especially mixtures comprising NF ₃ and Ar. Similarly, mixtures of fluorine with nitrogen or fluorine with helium are excellent drop-in substitutes for such inert gas and devices operating with mixtures comprising NF ₃ . If a certain inert gas to which the device is to be adjusted is included in a certain minimum amount in the gas mixture of fluorine and other types of inert gases, then the device adjusted for NF ₃ and certain inert gases such as, for example, argon, It can be operated as gas mixtures of any other inert gas. For example, if some argon is additionally introduced into the chamber, the regulated device for mixtures of argon and NF ₃ can be operated with mixtures of fluorine and nitrogen. Often, a minimum volume of 50% by volume of argon is sufficient to maintain an operable plasma without any adjustment of the apparatus. This minimum amount can be easily ascertained by checking the stability of the plasma, although it is sometimes dependent on the particular device. Of course, the additional inert gas required in terms of regulation may be included in a mixture of fluorine and other inert gases, or may be fed individually into the apparatus. A preferred Group 0 gas is argon. It is clear from the above that, in this preferred drop-in method, F ₂ gas can be selected instead of NF ₃ as a component of gas mixtures further comprising an inert gas.

It is preferable to use fluorine, nitrogen and argon, whereby at least fluorine and nitrogen are supplied as a gas mixture. If fluorine and nitrogen are supplied as separate mixtures with argon, the content of fluorine in the nitrogen / fluorine mixture is preferably in the range of 15 to 25% by volume, as indicated above. If argon is separately supplied with the fluorine / nitrogen mixture, the volume of the nitrogen / fluorine mixture and argon is controlled in such a manner that the content of argon in the total amount of nitrogen / fluorine and argon is preferably at least 50 vol%. In principle, the content of fluorine in the total amount of argon, nitrogen and fluorine gas forming the mixture in the reactor is elastic and may be in the range of 1 to 25% by volume. The content of nitrogen in the total amount of nitrogen, fluorine and argon gas in the reactor is also elastic; And may be in the range of 4 to 50% by volume. The argon preferably has a residual amount of up to 100% by volume. As mentioned above, fluorine and nitrogen are preferably supplied as a mixture wherein the volume ratio of fluorine to nitrogen is preferably within the range of 15:85 to 25:75. As a result, the content of fluorine and nitrogen is in the lower range. In particular, it is preferred to transport a nitrogen / fluorine mixture and argon in a reactor chamber wherein the total amount of this gas feed consists of fluorine, nitrogen and argon, wherein the fluorine content is in the range of 1 to 5 vol% The volume ratio of fluorine is in the range of 15:85 to 25:75, and the amount of argon is up to 100% by volume. The most preferred range of fluorine is 1 to 4% by volume. The preferred volume ratio of fluorine to nitrogen is 18:82 to 22:78, and argon is up to 100% by volume.

Instead of being transported separately by two different lines, the nitrogen / fluorine mixture and argon may also be carried in one line, where the nitrogen / fluorine mixture and argon are premixed before entering the reactor chamber, or 3 They may be preliminarily mixed and supplied in the form of a ternary mixture. Such a ternary mixture can be easily prepared by condensing a desired amount of fluorine, argon and nitrogen in a pressure bottle.

Fluorine as a drop-in for NF ₃ and inert gases in a plasma-operated apparatus for the treatment of semiconductor, solar panel, flat panel, for example in surface cleaning and chamber cleaning, The use of mixtures of inert bases is another aspect of the invention.

For most purposes, argon (Ar) is the preferred inert gas. For tungsten etching, N ₂ / F ₂ is more effective than Ar / F ₂ .

The method according to the present invention is widely applicable to applications for semiconductor, solar panel and flat panel (TFT / LCD) fabrication.

One aspect of the invention relates to the etching of materials used in semiconductor manufacturing or as a result of semiconductor manufacturing. For example, the fluorine and inert gases or mixtures of inert gases described can be used to etch inorganic materials, such as amorphous Si, and in particular SiON, TaN, TiN, W and SiO ₂ . These materials are often fabricated through CVD, PVD or ALD methods during semiconductor manufacturing. The mixture can also be used to etch organic materials such as photo resist. Here, the mixture is advantageously used with oxygen.

In another aspect of the present invention, the gas mixture outlined above is used to clean a chamber clean or a surface of a semiconductor substrate, a flat panel (TFT / LCD), and the like. As mentioned above, during the CVD, PVD or ALD process, inorganic or organic contamination can also occur in the semiconductor material processed in the chamber or in the chamber in which it is used.

For the etching of tungsten, the preferred mixture consists of fluorine and nitrogen. With respect to the etching of other inorganic materials, a preferred mixture, such as SiON, TaN, TiN, SiO ₂ and an amorphous Si is formed of fluorine and argon. If a binary mixture is used, particularly preferred is a mixture comprising 18 to 22% by volume of fluorine and the balance being nitrogen or argon, respectively. If a ternary mixture, which may sometimes be advantageous, is used, it is preferred that the content of fluorine is again in the range of 1 to 5% by volume.

In general, the pressure during the etching or chamber cleaning is lower than the atmospheric pressure (1 bar), i.e., in vacuum. The etching is preferably carried out at a pressure in the range of 100 to 2000 Pa. Very often, the pressure is preferably in the range of 100 to 1000 Pa, particularly preferably the pressure is in the range of 200 to 800 Pa, and more preferably in the range of 300 to 600 Pa. If desired, etching may be performed at lower or higher pressures than indicated, but the etch rate is low.

If the etching is carried out in the presence of a plasma, the temperature is preferably within the range of ambient temperature (about 20 캜) to 400 캜. Particularly preferably, the temperature is in the range of 100 占 폚 to 400 占 폚.

If etching is performed without plasma, the preferred temperature is given above.

According to another embodiment, a mixture of fluorine and an inert gas is used for chamber cleaning. If the interior of the chamber is contaminated with W, a mixture of fluorine and nitrogen is very suitable. For other contaminants, mixtures of fluorine and argon are preferred. The preferred ranges of temperature and pressure correspond to those given above for etching.

Also in this embodiment, the mixtures may be used in a method which is carried out without plasma or in a method which is supported by a plasma. If organic matter such as a fluorinated polycarbon material is removed, the addition of oxygen is advantageous.

The method according to the present invention can be practiced in devices commonly used for manufacturing semiconductors, TFTs, LCDs, solar panels and flat plates. It may be used, for example, in a CVD device, a PVD device, or an ALD device, operating with or without a plasma. The method is suitable for devices using remote plasma and for devices in which the plasma is directly manufactured in the chamber and is induced by radio-frequency energy or microwave energy.

In a preferred embodiment, the fluorine and inert gases are introduced as homogeneous premixed mixtures, not individually into the chamber. Whereby it is ensured that the pre-adjusted ratio of fluorine and inert gas is homogeneously provided throughout the reactor. If one uses ternary mixtures, the ternary mixtures may be provided in a premixed form or may be provided in a partially mixed form into the reactor. A preferred embodiment is the addition of previously mixed fluorine and argon or fluorine and nitrogen, and in the latter case, if desired, argon, which can also be carried out separately or in the form of a ternary mixture of fluorine and nitrogen .

An advantage of the process according to the invention is that NF ₃ can be replaced by an environmentally friendly gas mixture in terms of GWP and ozone; NF ₃ has a very high GWP while Ar, N ₂ , F ₂ and mixtures thereof have a GWP of zero. Considering that NF ₃ provides three F atoms and F ₂ provides only two F atoms, for many applications, the gas mixtures according to the invention are similar to conventional etching or cleaning methods using NF ₃ (For example, when amorphous Si, SiON or SiO2 is etched with F ₂ / Ar or F ₂ / N ₂ at 150 ° C or with TaN or SiON with F ₂ / N ₂ at 300 ° C) When etching, or when removing such contaminants from chamber cleaning). Another advantage of the process is that a mixture of fluorine and an inert gas can be used as a drop-in replacement for each of the mixtures comprising fluorine instead of NF ₃ . If the device is tuned for a mixture of NF ₃ and other inert gases (to obtain optimal etch gas effectiveness, the gas flow controller and the mass flow of the valve, the sample plate Heating, flow parameters such as flow volume and flow speed, reactor temperature, adjustment of the homogeneity of the flow throughout the reactor), the additional supply of inert gas to which the device is tuned provides operable conditions do. Thus, the device can be operated in the most flexible manner (without the recurrence of which is very time consuming and requires a lot of experimental work = experiment design) and can be operated with NF ₃ once, without excessive delay, It is also possible to operate.

Another aspect of the present invention is a compound of formula And at least one inert gas selected from the group consisting of nitrogen and Group 0 gases. In a preferred embodiment, the fluorine is included in the binary mixture in the range of 1 to 35% by volume. The fluorine content in the range of 15 to 25% by volume in the binary mixture is highly preferred, and the range of 18 to 22% by volume is even more preferred. A preferred Group 0 gas is Ar. Particularly preferably a mixture of 15 to 25% by volume of fluorine and 75 to 85% by volume of Ar, even more preferably a mixture of 18 to 22% by volume of fluorine and 78 to 82% by volume of Ar; Most preferably 20 vol.% Of fluorine and 80 vol.% Of Ar. These binary mixtures can of course be used with the gases additionally supplied; For example, a binary mixture comprising fluorine and nitrogen within the given volume range may be used with argon; As a result, the fluorine content in the reactor chamber is dependent on the amount of argon supplied and is thus reduced.

Another aspect of the invention relates to mixtures comprising, or preferably comprising, fluorine, nitrogen and at least one Group 0 gas. Ternary mixtures are preferred. The content of fluorine in such a ternary gas mixture is preferably in the range of 1 to 25% by volume, particularly preferably in the range of 1 to 5% by volume. The content of nitrogen is preferably in the range of 4 to 50% by volume. O group gases or O group gases preferably have a residual amount of up to 100% by volume. The volume ratio of fluorine to nitrogen is particularly preferred in the range of 15:85 to 25:75, and even more preferably in the range of 18:82 to 22:78. A preferred Group 0 gas is argon. Highly preferred gas mixtures consist of fluorine, nitrogen and argon wherein the fluorine content is in the range of 1 to 5 vol%, the fluorine to nitrogen ratio is in the range of 15:85 to 25:75, argon Is a residual amount of up to 100% by volume. In these mixtures, the preferred range of fluorine is from 1 to 4% by volume. The preferred volume ratio of fluorine to nitrogen is 18:82 to 22:78, and argon is up to 100% by volume.

The advantage of these gas mixtures is that they are well suited for application in the semiconductor industry, such as reactive ion etching, chamber cleaning, or for cleaning surfaces of semiconductor substrates, solar cell plates (TFT / LCD), and the like.

Another aspect of the invention is a process, particularly a device suitable for etching or surface-cleaning of semiconductors, solar cells or flat panels (TFT and LCDs) and is adjusted for NF ₃ containing gases, but fluorine; And a gas mixture comprising at least one inert gas selected from nitrogen and Group 0 gases. The meanings of the adjustments are described above: This is the adjustment of the mass flow of the gas flow control system and valves, etc., so that the apparatus is suitable for use with gases containing NF ₃ . In a preferred embodiment, the apparatus is connected to one or more vessels, for example, through a line, such as a pressure pass comprising gas mixtures containing fluorine as mentioned above.

Another aspect of the present invention is a component of a gas mixture applied to a plasma-supported treatment apparatus, such as a chamber cleaning, a semiconductor, a solar cell, and a surface treatment or etching of a flat panel (TFT and LCD) It is the use of fluorine as a drop-in replacement for NF ₃ . A preferred use is in a plasma apparatus operated with gases containing fluorine as a substitute, although this is adjusted for gases containing NF ₃ . The fluorine containing gases as well as the NF ₃ gas mixtures can be replaced, for example, with argon which is fed individually into the reactor and which only forms the mixture in the apparatus, and they are also fed into the reactor in a premixed form Mixtures containing such NF ₃ may be substituted.

An advantage of this application is that no adjustment is made to the other gas mixture, thus the time and expense can be saved by the drop form of the application.

According to the present invention, an effective gas mixture can be provided that is used to clean the chamber or etch inorganic contaminants.

Figure 1 shows the relative etch rates at 150 ° C, normalized in terms of the fluorine content, for gas mixtures of nitrogen or argon and fluorine, applied to certain inorganic materials often used in semiconductor and flat panel manufacturing. The dotted line shows a comparison of the etch rate of NF ₃ to 100%. Figure 2 shows the results when the etching is carried out at < RTI ID = 0.0 > 300 C. < / RTI >

The following examples will illustrate the invention in more detail, but they are not intended to limit the scope of the invention.

[Example]

Devices Used:

Experiments were carried out on a custom stainless steel, manufactured by MKS Astron, operating at 13.56 MHz, with a remote Astron Astex plasma source located 32 cm above the sample, Was carried out in a vacuum chamber (26 liter volume). The chamber is evacuated with a turbo molecular pump and a BOC Edwards dry pump. Exhaust gases were analyzed by mass spectroscopy; A differentially pumped Leybold-Inficon Transpector 200 amu unit was used. The samples were placed on a chuck in the center of the reactor chamber. The temperature in the chamber was controlled and could be varied between room temperature (near 20 [deg.] C) and 300 [deg.] C.

Before running the experiment, the vacuum system was first flushed down to the low flow of F ₂ / N ₂ and then passivated for several hours at high F ₂ / N ₂ pressure without any flow. This was repeated twice.

F ₂ / Ar and F ₂ / N ₂ mixtures were used in a volume ratio of 20:80 and stored in a 2 liter pressure vessel filled to 10 and 38 bar respectively.

The remote plasma source was generally ignited in the presence of pure argon. Immediately after the plasma was in a stable condition, a gas mixture containing fluorine was introduced. Fluorine and argon in a drop-in manner without any problems. Since the apparatus used was adjusted for Ar / NF ₃ mixtures, argon was continuously added to the apparatus in order to obtain a stable plasma when using a mixture of fluorine and nitrogen as an inert gas. In this way, fluorine / nitrogen mixtures could be used in a drop-in manner. Carrying fluorine / nitrogen and argon separately allows for an excellent adjustment of the argon content. The use of ternary mixtures of fluorine, nitrogen and argon has the advantage that the mixtures are already homogeneous when transported to the reactor.

Measurement of etching rate:

The etch rate was measured in situ by reflectometry using a 645 nm laser directed to the sample. The etch rate was calculated by dividing the thickness of the film by time when the removal endpoint was recognized.

Preparation of mixtures of argon, fluorine and nitrogen and fluorine :

Argon and fluorine were compressed in a 2-liter pressure vessel filled to a pressure of 10 Bar at a volume ratio of 20:80, thereby forming a homogeneous mixture of both compounds.

Nitrogen and fluorine were compressed in a 2-liter pressure vessel filled to 38 bar at a volume ratio of 20:80, thereby forming a homogeneous mixture of both compounds.

Samples :

The size of the sample was 20 x 20 mm ² . The irradiated material was deposited on a 150 nm thermal SiO ₂ layer that allowed for interferometric measurements. SiON and SiO ₂ samples were deposited on bulk silicon because their optical properties allowed interference measurements.

The following samples were used:

a) 1000 nm SiO _x N _y (referred to as SiON) on bulk silicon, deposited by a conventional TEOS / ozone CVD process,

b) 1000 nm SiO ₂ , thermally grown in bulk silicon

c) 300 nm tungsten deposited by a conventional PVD process

d) 300 nm TiN deposited by conventional PVD method

e) 200 nm TaN deposited by conventional PVD method

No etching was observed up to 300 DEG C under plasma-free conditions. This proved to be a deficiency in the peak for SiF ₄ in QMS (quadrupol mass spectrometer) measurements.

Example  One: Volume ratio  20:80 using a mixture of fluorine and nitrogen SiON Etching

a) The temperature in the reactor was set to 150 캜, and the plasma was ignited with argon, and immediately after the plasma ignition, the F ₂ / N ₂ mixture was introduced into the reactor at a flow rate of 100 sccm. Argon was additionally introduced at a flow rate of 640 sccm. Relative etching rates were measured at pressures of 100 Pa, 200 Pa, 400 Pa and 800 Pa. The etching rate was found to be optimal at 400 Pa.

b) The example was repeated with an argon gas flow of 900 sccm and an F ₂ / N ₂ gas flow rate of 100 sccm. On the other hand, it was confirmed that the optimum condition was 400 Pa, but the relative etch rate was lower due to the low concentration of fluorine.

Comparative Example  1: argon and NF ₃ Lt; / RTI > SiON Etching

Example 1 was repeated by introducing argon and NF ₃ at flow rates of 350 sccm and 20 sccm, respectively. Also here, the optimum etch rate was observed at 400 Pa.

Results: After normalizing the fluorine content (NF ₃ carries 3 F atoms while F ₂ only carries 2), the relative etch rate of Example 1a) is slightly higher than the etch rate of Comparative Example 1 , Example 1b) was slightly lower.

Example  2: Using an argon / fluorine mixture SiON Etching

A mixture of argon and fluorine (80:20 by volume) was introduced into the reactor at a flow of 100 sccm at various pressures and temperatures. Regardless of the temperature, the optimum relative etch rate was obtained at a pressure of 400 Pa. The highest etch rate was observed at 300 占 폚.

Results: At 300 ° C, the etch rate of 100 sccm Ar / fluorine is 50-60% consistent with the etch rate of 20 sccm NF3. The mass equivalence of 10.7 sccm NF ₃ for 20 sccm F ₂ (contained in the Ar / fluorine mixture) achieved a slightly smaller etch rate; Therefore, the etching rate per mass unit of Ar / F ₂ is slightly better.

Example  3: SiO2 , TiN , TaN  And etching of W

Examples 1 and NF ₃ for the mixture of, and a comparison of 2 and Comparative Example 1 Similar to SiO _2, (additionally supplying argon to the plasma stability) TiN, TaN and the argon / fluoride, nitrogen / fluorine to W Lt; / RTI >

a) Etching performed at < RTI ID = 0.0 > 150 C:

Standardized, relative etch rates for fluorine content are collected in FIG. It can be seen that the mixture of fluorine and nitrogen is similar or apparently much higher for W and SiON compared to NF ₃ (indicated as 100%, indicated by the dashed line). Compared to NF ₃ , the mixture of fluorine and argon is similar or apparently much higher for SiON, TiN and SiO ₂ . TaN can be etched with fluorine and argon in a competitive range compared to NF ₃ ; Tungsten etching using a mixture of fluorine and argon is possible, but the etching rate is relatively low.

b) Etching performed at 300 < 0 > C:

The results are collected in Fig. Using an argon / fluorine mixture, a very high etch rate was obtained for TaN, and using a nitrogen / fluorine mixture, SiON etching is very effective. Argon / fluorine is competitive with NF ₃ for the etching of TiN and SiON as much as the etching of W and SiON using a mixture of nitrogen and fluorine (additionally supplying argon for plasma stabilization, as described). Etching of W using argon / fluorine is possible, but the etching rate is relatively low.

Example  4: plasma -support chamber  washing

a) SiO _2, SiON, TiN, TaN and the plasma chamber contamination by inorganic materials such as W are argon and fluorine or nitrogen and fluorine (if, if the reactor is adjusted for the NF ₃ / Ar, advantageously on the other hand additional Gt; argon) < / RTI > The plasma starts with argon, and then an etch gas mixture (here a cleaning gas mixture) is introduced into the reactor. The pressure is preferably in the range of 100 to 800 Pa, and is optimal at 400 Pa. The temperature is preferably in the range of 150 to 300 占 폚. The treatment is carried out until a desired cleaning degree is obtained. Gas reaction products formed from contaminants (such as SiF ₄ ) can be removed by applying a vacuum to the cleaned reactor chamber.

Such a cleaning step may be performed at regular intervals whenever the cleaning is desired.

b) The plasma chambers may be contaminated with an organic material, for example a polymeric carbon material which may be partially or fully fluorinated. If the semiconductor or flat panel, such as an etching gas can lead to such contamination when the etching conditions in the plasma using a fluorocarbon or hydrogenated fluorocarbon such as CF4 _4, C ₂ F _6, or CHF _3. The chambers contaminated with the organic material are each cleaned at a temperature of 250 DEG C using a mixture of argon, fluorine or nitrogen and fluorine, as described in Example 4a). On the other hand, the plasma is started using argon, and then the cleaning gas is introduced into the chamber. It is also highly desirable to introduce oxygen into the chamber to be cleaned. The reaction products formed from organic contaminants such as CO ₂ , (hydrogenated) fluorocarbon products or carbonyl fluoride can be removed from the cleaned chamber by applying a vacuum. Such chamber cleaning can be performed periodically whenever the cleaning operation is desired.

Example  5: Surface cleaning of semiconductor, flat plate, etc.

Semiconductors, flat plates, etc. are often etched using fluorocarbon or hydrogen fluoride etch gases such as CF ₄ , C ₂ F ₆ or CHF ₃ . Under plasma conditions, the organic material may be formed not only inside the reactor chamber, but also on the surface of the etched semiconductor or plate. These surface contaminants can be removed using a mixture of argon and fluorine or nitrogen and fluorine, respectively. With respect to pressure and temperature, a preferred range is given in Example 4a. As in Example 4b, the reaction products can be removed from the chamber in which the semiconductor or flat plate is located by applying a vacuum.

Example  6: Plasma  Do not have( Plasma - free ) work

Surface cleaning such as etching, chamber cleaning, and semiconductor, flat plate, etc., can be performed under plasma-free conditions. Here, the temperature is preferably 400 DEG C or higher, but can be significantly higher up to 650 DEG C, up to 800 DEG C, or much more. If desired, the etching or cleaning action may be supported by UV light.

Example  7: Using a ternary mixture of nitrogen, fluorine and argon chamber  washing

A) Preparation of the gas mixture: Compress the fluorine, nitrogen and argon in a pressure vessel with the volume ratio given in the table below (data given in vol%):

Example Fluorine nitrogen argon 7.1 1.8 7.2 91 7.2 2.25 9 88.75 7.3 2.6 10.4 87

The gas mixtures of Examples 7.1 to 7.3 may also be prepared by pressing a gas mixture of fluorine and nitrogen (20: 80 by volume) in a pressure vessel and adding argon before or after.

B) Application of ternary mixtures for etching:

The perfectly homogeneous mixtures of Examples 7.1 to 7.3 can be used for etching or chamber cleaning of semiconductors similar to Examples 1-6. The advantage is that the ternary mixtures are already homogeneous before they are introduced into the reactor chamber.

Example  8 : Amorphous Si Processing

Amorphous Si can be fabricated in a plasma-free or plasma-supported CVD apparatus in the frame of semiconductor, solar panel or flat panel manufacturing. Undesirable deposition occurs in the chamber, often near the source of the silicium precursor.

8.1 Plasma-supported chamber cleaning

The plasma chamber with undesired deposition of amorphous Si contained fluorine / argon, fluorine / nitrogen mixtures (20:80 by volume) or 90 vol% Ar at a pressure of 400 Pa and a temperature of 250 占 폚, Is treated with ternary mixtures of a mixture of fluorine and nitrogen (20: 80 by volume).

8.2 Plasma-free chamber cleaning

The reactor chamber with undesired deposition of amorphous Si is treated with a mixture of fluorine and nitrogen (20: 80 by volume) at a temperature of 700 占 폚 to remove Si deposition.

Claims (1)

The use of mixtures comprising or consisting of fluorine, nitrogen and at least one Group 0 gas for etching or surface cleaning of semiconductor materials, solar panels or flat panels (TFT and LCD), or chamber cleaning of devices used in semiconductor fabrication .

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