JP5107134B2 - Cleaning method - Google Patents

Description

  The present invention relates to a cleaning method suitably used in the manufacturing process of various substrates such as a micro electro mechanical system (MEMS) and a large scale integrated circuit (LSI).

In order to manufacture LSI and MEMS, a fine pattern is required. Such a fine pattern is an etching pattern formed by performing etching using a resist pattern formed through exposure, development, and rinsing as a mask, and then cleaning. For the etching, plasma etching using a fluorine-based gas is mainly used. In order to improve pattern dimensional accuracy in plasma etching, it is necessary to perform etching while depositing a plasma polymerization film on the pattern side wall. Thereby, the side etching which arises in the case of an etching can be prevented. Side etching is a phenomenon in which reactive species (for example, fluorine radicals) generated by gas plasma diffuse laterally to increase the pattern dimension.
For example, in silicon oxide film etching, CF ₂ fragments are generated by hydrotrifluorocarbon CHF ₃ added to CF ₄ gas plasma, and a plasma polymerized film having a structure composed of (CF ₂ ) _n is generated. In silicon etching, by alternately generating sulfur hexafluoride SF ₆ and C ₃ F ₈ plasma serving as a (CF ₂ ) _n source, side etching can be prevented by repeating etching and plasma polymerization film deposition.

As described above, deposition of a plasma polymerized film is indispensable in plasma etching, but it is necessary to remove the plasma polymerized film after the etching is completed. That is, when the etching is completed, as shown in FIG. 3A, for example, the plasma polymerization film 54 is deposited on the side surface of the pattern 53, so that it is removed and the state shown in FIG. Is essential. In the figure, reference numeral 51 denotes a substrate and 52 denotes a base film.
If the plasma polymerized film remains, it causes defects, contamination, and particles, and causes a reduction in manufacturing yield, but removal of the plasma polymerized film is not easy. Further, the plasma polymerized film is not specifically composed of only the polymer composed of (CF ₂ ) _n , but an etching reaction product such as silicon or a base film component (for example, a metal such as tungsten) of the film to be etched. The presence of these etching residue components makes the removal of the plasma polymerized film more difficult.

  Further, such a plasma polymerized film also adheres to the inner wall of an apparatus that performs plasma etching. Conventionally, the plasma polymerized film on the inner wall of the apparatus has been cleaned by a method of immersing it in a cleaning solution and scraping it off with a brush or the like.

  As a cleaning method using a fluorinated solvent, a method of cleaning and removing oils and fats using chlorofluorocarbon (CFC) has been well known, but recently, a hydrofluoric solvent having a high fluorine content and a low surface tension. Substrates are cleaned using fluoroether (HFE) or hydrofluorocarbon (HFC). As the cleaning process, for example, as shown in FIG. 4 (a), the substrate 62 is immersed in the fluorine-based solvent 61 at room temperature, and at the same time, the fluorine-based solvent 61 and The substrate 62 is vibrated. Thereafter, as shown in FIG. 4B, the solvent is vaporized by heating the fluorine-based solvent with a heater 65, and the fluorine-based solvent vapor 66 generated thereby is applied to the substrate 62 so as to cover the surface of the substrate 62. Rinse and dry.

The following Patent Document 1 relates to a method of cleaning a resist adhering to a device substrate with a fluorine-containing solvent. A method of immersing a device substrate in a fluorine-containing solvent at room temperature or 30 ° C. A method of bringing a device substrate into contact with a solvent and a method of bringing the device substrate into a supercritical state after immersing the device substrate in a fluorine-containing solvent at room temperature or 30 ° C. are described.
International Publication No. 2007/114448 Pamphlet

However, a general cleaning method using a fluorine-based solvent cannot obtain a high cleaning effect to such an extent that the plasma polymerized film can be satisfactorily removed.
The present invention has been made to solve the above-described problems, and provides a cleaning method that can satisfactorily remove an object to be cleaned having a plasma polymer generated in a plasma etching process using a fluorine-containing gas. The purpose is to provide.

In order to solve the above-described problems, the cleaning method of the present invention includes a cleaning process including an immersion process in which an object to be cleaned having a plasma polymer generated in a plasma etching process using a fluorine-containing gas is immersed in a cleaning liquid containing a fluorine-containing compound. In the method, the fluorine-containing compound has a linear or branched perfluoroalkyl group having 6 or more carbon atoms.
The fluorine-containing compound is preferably one or more selected from the group consisting of hydrofluoroethers and hydrofluorocarbons.
The fluorine-containing compound is preferably a hydrofluoroether in which a perfluoroalkyl group and an alkyl group are bonded through an ether bond.
Alternatively, the cleaning method includes an immersing step in which an object to be cleaned having a plasma polymer generated in a plasma etching step using a fluorine-containing gas is immersed in a cleaning liquid containing a fluorine-containing compound , wherein the fluorine-containing compound is C _The cleaning method is characterized by being a hydrofluorocarbon represented by _{n + m} F _{2n + 1} H _{2m + 1} (where n is an integer of 5 to 9, and m is an integer of 0 to 2) .

  According to the cleaning method of the present invention, an object to be cleaned having a plasma polymer generated in a plasma etching process using a fluorine-containing gas can be removed satisfactorily.

<Cleaning liquid containing fluorine-containing compound>
[Fluorine-containing compounds]
The fluorine-containing compound used in a cleaning liquid containing a fluorine-containing compound (hereinafter sometimes referred to as a fluorine-based solvent) has a perfluoroalkyl group.
A perfluoroalkyl group (hereinafter sometimes referred to as Rf group) in the fluorine-containing compound is bonded to a carbon atom of a chain-like or branched alkyl group represented by C _n H _{2n + 1} (n is an integer). It is a group (C _n F _{2n + 1} (n is an integer)) in which all hydrogen atoms are substituted by fluorine atoms. In the present invention, the carbon number (n) of the Rf group is 5 or more, and more preferably 6 or more. When the carbon number (n) of the Rf group is 5 or more, the removal effect of the plasma polymer is high.
When the fluorine-containing compound has two or more Rf groups in one molecule, at least one has only to have 5 or more carbon atoms (n), more preferably 6 or more. More preferably, all Rf groups have 5 or more carbon atoms (n), preferably 6 or more.
The Rf group having a carbon-carbon bond chain having 6 or more carbon atoms (n) may contain an etheric oxygen atom. That Rf _{group, C p F 2p + 1 -O} -C q F 2q - (. P, q are each independently an integer of 1 or more, p or at least one is 5 or more q) a group represented by It may be. In this case, the number of carbon atoms in the Rf group is the sum of p and q (p + q), which is 6 or more. Of the p and q, at least p is preferably 5 or more.
The upper limit of the carbon number of the Rf group is preferably 10 or less, more preferably 9 or less, and still more preferably 8 or less, from the viewpoint of drying properties after washing and the melting point and viscosity for handling as a liquid.
The fluorine-containing compound having a perfluoroalkyl group is preferably at least one selected from the group consisting of perfluorocarbons, hydrofluoroethers, and hydrofluorocarbons. Among these, at least one selected from hydrofluoroethers and hydrofluorocarbons is preferable in that the global warming potential is small and the environmental load is small.
A fluorine-containing compound may be used individually by 1 type, and 2 or more types may be mixed and used for it.

The hydrofluoroether preferably has a perfluoroalkyl group and an alkyl group bonded via an ether bond.
Specific examples of the hydrofluoroether having an Rf group having 5 or more carbon atoms include methyl perfluoropentyl ether (C ₅ F ₁₁ OCH ₃ ), ethyl perfluoropentyl ether (C ₅ F ₁₁ OCH ₂ CH ₃ ), and methyl perfluoro ether. Fluorohexyl ether (C ₆ F ₁₃ OCH ₃ ), ethyl perfluorohexyl ether (C ₆ F ₁₃ OCH ₂ CH ₃ ), methyl perfluoroheptyl ether (C ₇ F ₁₅ OCH ₃ ), ethyl perfluoroheptyl ether (C ₇ F ₁₅ OCH ₂ CH ₃ ), methyl perfluorooctyl ether (C ₈ F ₁₇ OCH ₃ ), ethyl perfluorooctyl ether (C ₈ F ₁₇ OCH ₂ CH ₃ ), methyl perfluorononyl ale (C ₉ F ₁₉ OCH) _3), Echirupafu Oro nonyl ether _{(C 9 F 19 OCH 2 CH} 3), methyl perfluoro decyl ether _{(C 10 F 21 OCH 3)} , ethyl perfluoro decyl ether _{(C 10 F 21 OCH 2 CH} 3) , and the like.

Among these, methyl perfluoropentyl ether (C ₅ F ₁₁ OCH ₃ ), from the viewpoint of ease of use as a cleaning agent (dryness after cleaning, can be handled as a low-viscosity liquid at room temperature, etc.), Ethyl perfluoropentyl ether (C ₅ F ₁₁ OCH ₂ CH ₃ ), methyl perfluorohexyl ether (C ₆ F ₁₃ OCH ₃ ), ethyl perfluorohexyl ether (C ₆ F ₁₃ OCH ₂ CH ₃ ), methyl perfluoroheptyl Ether (C ₇ F ₁₅ OCH ₃ ), ethyl perfluoroheptyl ether (C ₇ F ₁₅ OCH ₂ CH ₃ ), methyl perfluorooctyl ether (C ₈ F ₁₇ OCH ₃ ), ethyl perfluorooctyl ether (C ₈ F) ₁₇ OCH ₂ CH ₃ ) is preferred.

The hydrofluorocarbon is preferably represented by C _{n + m} F _{2n + 1} H _{2m + 1} (where n is an integer of 5 to 9, and m is an integer of 0 to 2).
Specific examples of hydrofluorocarbons having an Rf group having 5 or more carbon atoms include
1H-mono decafluoropentane _{(C 5 F 11 H),} 3H- mono decafluoropentane _{(C 5 F 11 H),} 1H- tridecafluoro hexane _{(C 6 F 13 H),} 1H- pentadecafluorooctyl heptane (C ₇ F ₁₅ H), 3H- pentadecafluorooctyl heptane _{(C 7 F 15 H),} 1H- heptadecafluorooctanesulfonic _{(C 8 F 17 H),} 1H- nonadecamethylene fluoro nonane _{(C 9 F 19 H),} 1H- Perfluorodecane (C ₁₀ F ₂₁ H), 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane (C ₆ F ₁₃ CH ₂ CH ₃ ), 1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8- heptadecafluoro decane _{(C 8 F 17 CH 2 CH} 3) Etc.

Among these, 1H-monodecafluoropentane (C ₅ F ₁₁ H), from the viewpoint of ease of use as a cleaning agent (dryness after cleaning, can be handled as a low-viscosity liquid at room temperature, etc.), 3H- mono decafluoropentane _{(C 5 F 11 H),} 1H- tridecafluoro hexane _{(C 6 F 13 H),} 1H- pentadecafluorooctyl heptane _{(C 7 F 15 H),} 3H- pentadecafluorooctyl heptane (C ₇ F ₁₅ H), 1H-heptadecafluorooctane (C ₈ F ₁₇ H), 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane _{(C 6 F 13 CH 2 CH} 3) are preferred.

Perfluorocarbons include compounds in which all hydrogen atoms of chain or branched hydrocarbons are substituted with fluorine atoms (fully fluorinated hydrocarbons); all hydrogen atoms of alkyl groups of chain or branched alkylamines. Compounds substituted with fluorine atoms (perfluorinated alkylamines);
Examples include compounds in which all hydrogen atoms of a chain or branched alkyl ether are substituted with fluorine atoms (fully fluorinated alkyl ethers).
The preferable carbon number in the hydrocarbon, the alkyl group of the alkylamine, and the alkyl ether is the same as the preferable carbon number of the Rf group.
The content of the fluorine-containing compound in the cleaning liquid is preferably more than 50% by mass, more preferably more than 80% by mass.

[Other fluorine-containing compounds]
While using the said fluorine-containing compound which has a C5 or more linear or branched perfluoroalkyl group, you may use together the other fluorine-containing compound which is not contained in this.
Other fluorine-containing compounds include hydrochlorofluorocarbons (for example, dichloropentafluoropropane, dichlorofluoroethane, etc.); fluorine-containing ketones; fluorine-containing esters, fluorine-containing unsaturated compounds; fluorine-containing aromatic compounds, and the like. It is done.
These may be used alone or in combination of two or more.
It is preferable to select and use a liquid or supercritical fluid under the temperature and pressure conditions in the dipping process.
The content of these other fluorine-containing compounds in the cleaning liquid (fluorinated solvent) is preferably 50% by mass or less, and more preferably 20% by mass or less.

[Fluorine-containing alcohol]
The cleaning liquid (fluorinated solvent) in the present invention may contain a fluorinated alcohol. The fluorine-containing alcohol means a compound having a fluorine atom and a hydroxy group. The fluorine-containing alcohol is preferably selected from known compounds that are liquid or supercritical fluid under the temperature and pressure conditions in the dipping process. It is more preferable to form an azeotropic mixture with the fluorine-containing compound contained in the cleaning liquid.
Specific examples of the fluorinated alcohol include 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 2,2,3,3,3-pentafluoropropanol, 2,2,3, 4,4,4-hexafluorobutanol, 2,2,2-trifluoro-1- (trifluoromethyl) ethanol, 2,2,3,3,4,4,5,5-octafluoropentanol, 1 1,1,3,3,3-hexafluoroisopropanol and the like.
The content of the fluorinated alcohol in the cleaning liquid (fluorinated solvent) is preferably in the range where the total amount with the organic solvent described later is about 5 to 20% by mass.

[Organic solvent not containing fluorine atoms]
The cleaning liquid (fluorinated solvent) in the present invention may further contain an organic solvent having no fluorine atom. The organic solvent is preferably selected from known ones that are liquid under the temperature and pressure conditions in the dipping process. It is more preferable to form an azeotropic mixture with the fluorine-containing compound contained in the cleaning liquid.
Specific examples of the organic solvent include alcohols such as ethanol and 2-propanol; acetates such as propylene glycol monomethyl ether acetate; amines such as dimethylethanolamine, allylamine and aminobenzylamine.
These organic solvents can also be used as a pH adjuster, and by adding them, the zeta potential necessary to prevent reattachment of particles can be adjusted.

[Other ingredients]
The cleaning liquid (fluorinated solvent) in the present invention contains, in addition to the above-mentioned fluorine-containing compound, other fluorine-containing compound, fluorine-containing alcohol, and organic solvent, other components having no fluorine atom as necessary. Can do.
For example, nonionic surfactants such as sorbitan fatty acid ester, polyoxyethylene alkylamine fatty acid amide, alkyl monoglyceryl ether; amphoteric surfactants such as alkyldimethylamine oxide; anionic surfactants such as monoalkyl sulfates; alkyltrimethylammonium Surfactants such as cationic surfactants such as salts may be added alone or in combination of two or more.
When the surfactant is added, the addition amount is preferably 0.01 to 5% by mass in the cleaning liquid (fluorinated solvent).

  The method for preparing the cleaning liquid (fluorinated solvent) is not particularly limited, and can be obtained by uniformly mixing the above-mentioned fluorine-containing compound and components added as necessary.

<To be cleaned>
In the cleaning method of the present invention, the object to be cleaned, which is the object of cleaning, includes a plasma polymer.
The plasma polymer in the present invention is a deposit generated in a plasma etching process using a fluorine-containing gas, and is a compound (for example, C ₃ ) that can form a CF ₂ fragment serving as a (CF ₂ ) _n source in the fluorine-containing gas. Many are formed when F ₈ , CHF ₃ ) are contained. Further, CH ₂ fragments and the like generated by decomposition of the resist pattern during plasma etching may be involved in the formation of the plasma polymerized film. The plasma polymer includes those containing an etching residue component.
The plasma polymer was difficult to clean well by the conventional cleaning method using a fluorine-based solvent, but can be removed well by using the cleaning method of the present invention.

  For example, in the manufacturing process of various substrates such as micro electro mechanical system (MEMS) and large scale integrated circuit (LSI), plasma polymerization film deposited on the substrate and plasma polymerization adhered to the inner wall of the apparatus for performing plasma etching It is preferable to apply to the removal of the film.

<Washing method>
The cleaning method of the present invention will be described. A plasma polymerized film on a substrate will be described as an example of the object to be cleaned.
[Immersion process]
The substrate is immersed in a fluorine-based solvent (cleaning liquid) in an open or closed container (immersion process). At this time, it is preferable to perform immersion under the following conditions (a) or (b).
(A) The temperature of the fluorinated solvent is raised to a temperature of 80 ° C. or higher. The fluorinated solvent is in a liquid state or a supercritical state. A liquid state is preferred. When making the temperature of a fluorine-type solvent more than the boiling point of the fluorine-containing compound contained in this, it is preferable to perform an immersion process under pressure with a closed system. When the temperature of the fluorinated solvent is lower than the boiling point of the fluorinated compound contained therein, the immersion step may be carried out in an open system, but is preferably carried out in a closed system or an apparatus provided with a reflux part. .
The upper limit of the temperature of the fluorinated solvent in the dipping process is not particularly limited, but a sufficient cleaning effect can be obtained at 200 ° C. or lower. If the temperature is increased more than necessary, the cost becomes disadvantageous.
(B) The temperature of the fluorinated solvent is set to room temperature (25 ° C.) or more and less than 80 ° C., and ultrasonic waves are applied to vibrate the fluorinated solvent and the substrate.
In particular, the condition (a) is more preferable in that the plasma polymer can be removed satisfactorily.
The method of performing the dipping step under the conditions (a) or (b) can be performed by appropriately using a known method as a method of cleaning an object to be cleaned other than the plasma polymerization film with a fluorine-based solvent.

In the dipping process, the time for dipping the substrate in the fluorinated solvent (dipping time) is too short if the cleaning effect is insufficient, and if it is too long, the cleaning efficiency is lowered. . For example, the immersion time is preferably 1 to 120 minutes, more preferably 10 to 60 minutes.
If necessary, the fluorinated solvent may be exchanged one or more times during the dipping process. When exchanging the fluorinated solvent, the type of the fluorinated solvent, the temperature (t) of the fluorinated solvent, and / or the atmospheric pressure may be changed.
The dipping step may be performed not continuously but in a continuous manner in which a fluorine-based solvent is allowed to flow at an appropriate flow rate.

[Supercritical process]
In this method, after immersing the substrate in a fluorinated solvent in a liquid state for a predetermined immersing time in the immersing step (immersion step), the temperature of the fluorinated solvent is set to a critical temperature or higher and the atmospheric pressure is set to a critical pressure or higher. By doing so, you may perform the process (supercritical process) which uses the fluorine-type solvent in which the board | substrate is immersed as a supercritical fluid.
Since the diffusion rate is increased by setting the supercritical state, the fluorinated solvent that has become a supercritical fluid penetrates into a fine region and can be cleaned in detail. Thereby, the cleaning effect can be further improved. Also, when dried in a supercritical fluid state, the surface tension does not act in the supercritical state, so unnecessary stress is not applied, and the structure such as the pattern formed on the substrate is dried without breaking. be able to.

  In the supercritical process, if the time for contacting the substrate with the fluorine-based solvent in the supercritical state (contact time) is too short, the cleaning effect is not sufficiently improved. The range may be set. For example, the contact time is preferably 1 to 120 minutes, more preferably 10 to 60 minutes.

When the predetermined immersion time is completed, or when the supercritical process is performed, when the predetermined contact time is completed, the heated fluorine-based solvent is discharged. Further, when the process is performed in a closed system, the sealed container is opened to atmospheric pressure. Finally, the substrate is taken out. Then, it is made to dry as needed.
In particular, when the fluorinated solvent is heated above the normal boiling point or in a supercritical state in a sealed container, the fluorinated solvent adhering to the substrate surface is instantly released by opening the sealed container. After drying, the substrate becomes dry. Therefore, no specific drying means is required.
In this way, a substrate cleaned with a fluorinated solvent is obtained.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
<Example of plasma polymerization film removal test>
Table 1 shows the cleaning effect when the plasma polymerized film is cleaned using a fluorine-based solvent composed of various fluorine-containing compounds. The fluorine-based solvent (cleaning liquid) is composed of 100% by mass of the fluorine-containing compound shown in the table. As the object to be cleaned, a plasma polymerized film (non-patterned solid film) having a thickness of 800 to 900 nm deposited on a silicon substrate using C ₃ F ₈ gas plasma was used.

[Cleaning conditions]
(1) 30 ° C./ultrasonic wave: immersed in a fluorine-based solvent whose temperature is adjusted to 30 ° C. in an atmospheric pressure, washed with a method of vibrating the fluorine-based solvent and the substrate with an ultrasonic transmitter, and then washed at 120 ° C. It was dried by heating in an oven for 1 hour.
(2) 100 ° C .: A fluorinated solvent was introduced into the sealed space, heated to 100 ° C., and the substrate was immersed in the fluorinated solvent in this state for 1 hour and taken out.

[Evaluation]
The substrate cleaned under each condition was visually observed. If the plasma polymerized film remained over the entire surface, x, part of the plasma polymerized film could be removed but not completely removed, and Those that could be removed were marked with ○.

From the results shown in Table 1, it was found that both the straight chain or branched perfluoroalkyl group having 5 or more carbon atoms was contained in both the case of washing at 30 ° C. under ultrasonic conditions and the case of washing at 100 ° C. under heating conditions. In the case of cleaning with a fluorine compound (Test Examples 6 to 10), it was confirmed that the plasma polymerization film was completely removed. This is because the plasma polymerized film has a structure composed of (CF ₂ ) _{n which} is considered to be the main component, and the carbon chain of the Rf group (C _n F _{2n + 1} ) in the fluorine-based solvent is longer (n is longer). This is probably because the plasma polymerization film tends to swell and dissolve as a result.

FIGS. 1 and 2 show the side surface of a silicon pattern etched by alternating treatment of SF ₆ gas plasma and C ₃ F ₈ gas plasma (FIG. 1 is 100 μm wide, FIG. 2 is 20 μm wide, and both are 40 μm deep). of ₆ F ₁₃ CH ₂ CH ₃ when washed with (test example 7) is a graph showing Auger spectroscopy results of examining the degree of cleaning.
Cleaning was performed by immersing the pattern in C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7) heated to 80 ° C. in a sealed state for 30 minutes.
From the results in this figure, it can be seen that the fluorine concentration is lowered to the detection limit or less after cleaning, that is, the plasma polymerized film is completely removed without depending on the pattern width and pattern depth.

As described above, according to the cleaning method of the present invention, an object to be cleaned having a plasma polymerization film generated in a plasma etching process using a fluorine-containing gas can be satisfactorily cleaned to remove the plasma polymerization film.
Therefore, for example, the plasma polymer adhered to the inner wall cover of the etching apparatus used in the plasma etching process using fluorine-containing gas and the plasma polymer film on the pattern inner wall processed in the etching process can be efficiently removed. . Such a plasma polymerized film often contains an etching residue component in addition to the plasma polymer, but even in that case, the plasma polymerized film can be removed satisfactorily.

[Example 1]
A resist pattern having a width of 50 to 300 nm was formed on the silicon substrate by using known photolithography. This silicon substrate was etched by alternating processing of SF ₆ gas plasma and C ₃ F ₈ gas plasma to form a pattern made of silicon.
Thereafter, the substrate was transferred to a sealable container, a fluorine-based solvent composed of C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7) was introduced into the container, and the substrate was immersed in the fluorine-based solvent. .
The container was sealed, and the temperature of the inside of the container and the fluorinated solvent was increased to 90 ° C. After 30 minutes, the fluorine-based solvent was discharged outside the sealed container while keeping the temperature in the sealed container constant, and the substrate was taken out of the container. Drying was not necessary. In the obtained substrate, the plasma polymerization film adhering to the pattern side wall was dissolved and removed.

[Example 2]
The substrate prepared in the same manner as in Example 1 was immersed in a cleaning tank heated to 50 ° C. with a fluorine-based solvent composed of C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7), and ultrasonic at 20 to 100 kHz. After washing by sonic vibration for 10 minutes, the fluorine-based solvent composed of C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7) was transferred to a steam rinse bath heated to the boiling point, and C ₆ F ₁₃ CH ₂ CH ₃ Steam rinsing was performed for 5 minutes. Thereafter, the substrate was taken out of the steam rinse bath and dried as it was. In the obtained substrate, the plasma polymerization film adhering to the pattern side wall was dissolved and removed.

[Example 3]
An inner wall cover of an etching apparatus using C ₃ F ₈ gas plasma or CHF ₃ gas plasma is transferred to a sealable container, and fluorine containing C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7) is placed in the container. A system solvent was introduced, and the inner wall cover was immersed in the fluorinated solvent.
In this state, the temperature of the inside of the container and the fluorinated solvent was raised to 100 ° C. After 30 minutes, the fluorine-based solvent was discharged outside the sealed container while keeping the temperature in the sealed container constant, and the inner wall cover was taken out from the container. Drying was not necessary. In the obtained inner wall cover, the plasma polymerized film adhering thereto was dissolved and removed.

[Example 4]
A resist pattern with a width of 30 to 100 nm was formed on a substrate on which a copper wiring was formed and an insulating film made of methylsilsesquioxane was formed using known photolithography. The insulating film was etched by CHF ₃ / CF ₄ / Ar mixed gas plasma to form an insulating film pattern. After that, the substrate was transferred to a sealable container having a temperature of 100 ° C. to make it sealed. A fluorine-based solvent composed of C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7) was introduced into the container, and the substrate was immersed in the fluorine-based solvent. The plasma polymerization film adhering to the pattern side wall was dissolved and removed while the fluorine-based solvent was allowed to flow at 100 cc / min per minute. After 10 minutes, the fluorine-based solvent was discharged outside the sealed container while keeping the temperature in the sealed container constant, and the substrate was taken out of the container. Drying was not necessary. In the obtained substrate, the plasma polymerization film adhering to the pattern side wall was dissolved and removed.

[Example 5]
In Example 1, the fluorine-based solvent was changed to a mixed solution in which 90% by mass of C ₆ F ₁₃ H (Test Example 9) and 10% by mass of dimethylethanolamine were mixed to make the solution alkaline, and the temperature in the container was set to 100. The back pressure valve was adjusted so that the pressure in the container was 0.8 MPa. Others were the same as in Example 1, and the substrate was immersed in a fluorinated solvent for 30 minutes. Thereafter, the fluorinated solvent was discharged outside the sealed container while keeping the temperature in the sealed container constant, and the substrate was taken out of the container. Drying was not necessary. In the obtained substrate, the plasma polymerization film adhering to the pattern side wall was dissolved and removed.

[Example 6]
In this example, the ceramic apparatus parts set inside the inductively coupled plasma etching apparatus using C ₃ F ₈ gas plasma were cleaned.
First, the ceramic device parts were transferred to a sealable container, and the container was filled with a fluorine-based solvent composed of C ₆ F ₁₃ CH ₂ CH ₃ (Test Example 7).
The container was sealed, and the temperature of the inside of the container and the fluorinated solvent was raised to 100 ° C. After 30 minutes, the fluorine-based solvent was discharged outside the sealed container while keeping the temperature in the sealed container constant, and the ceramic device parts were taken out of the container. Drying was not necessary.
In the obtained ceramic device part, the plasma polymerized film adhering thereto was dissolved and removed.

It is a figure which shows the cleaning effect of the plasma polymerization film | membrane by the cleaning method of this invention. It is a figure which shows the cleaning effect of the plasma polymerization film | membrane by the cleaning method of this invention. It is a figure for demonstrating the removal process of a plasma polymerization film | membrane. It is a figure for demonstrating the washing | cleaning method of the conventional board | substrate.

Explanation of symbols

51 substrates,
52 Undercoat film,
53 patterns,
54 Plasma polymerized film.

Claims (4)

A cleaning method having a dipping step of immersing an object to be cleaned having a plasma polymer generated in a plasma etching step using a fluorine-containing gas in a cleaning liquid containing a fluorine-containing compound,
The cleaning method, wherein the fluorine-containing compound has a linear or branched perfluoroalkyl group having 6 or more carbon atoms.   The cleaning method according to claim 1, wherein the fluorine-containing compound is at least one selected from the group consisting of hydrofluoroethers and hydrofluorocarbons.   The cleaning method according to claim 2, wherein the fluorine-containing compound is a hydrofluoroether in which a perfluoroalkyl group and an alkyl group are bonded via an ether bond. A cleaning method having a dipping step of immersing an object to be cleaned having a plasma polymer generated in a plasma etching step using a fluorine-containing gas in a cleaning liquid containing a fluorine-containing compound,
Cleaning method wherein the fluorine-containing compound _{is, C n + m F 2n +} 1 H 2m + 1 ( where, n is an integer of 5 to 9, m is the integers from 0 to 2.) Characterized in that it is a hydrofluorocarbon represented by .

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