JP5069582B2 - Method for forming silica film - Google Patents

Description

  The present invention relates to a method for producing a silica film.

Silica films have excellent properties such as heat resistance, wear resistance, corrosion resistance, and high insulation, and are therefore used in various applications such as interlayer insulation films for semiconductor devices.
As a method for forming a silica film, various methods such as a dry process such as a sputtering method and a CVD method, and a wet process such as a sol-gel method and a spin coating method have been proposed.
The sol-gel method requires a firing temperature of 500 ° C. or higher, and is not used for applications in which the substrate is processed at a low temperature. The sputtering method or the CVD method requires that the substrate be held under reduced pressure, There were problems such as taking a long time.

  In order to solve these problems, for example, Patent Document 1 discloses a method of forming a silicon oxide film by converting polysilazane. This is a method in which a polysilazane-containing film is first formed, and this film is subjected to heat treatment twice at a temperature of 300 ° C. or higher and a temperature of 350 ° C. or higher to form a silica film. Although UV irradiation may be performed instead of the first heat treatment, the heat treatment is performed at a temperature of 350 ° C. or more in the second time. Further, the processing time requires about 1 hour in total.

  Patent Document 2 discloses a method for promoting the conversion of a polysilazane coating film to a silica film. The conversion reaction of the polysilazane coating film to a silica film is promoted by curing the coating film containing polysilazane or its modified product as a main component and then treating it with high temperature water containing an ammonium salt. Specifically, after heat treatment at 350 ° C. for 1 minute, this substrate was immersed in a 10 wt% ammonium carbonate aqueous solution and treated in a boiling state for 1 hour. Heat treatment at a temperature of 0 ° C. or higher is required, and the processing time is also required to be one hour or longer.

  Patent Document 3 discloses a method for forming a siliceous ceramic film and a ceramic film formed by the same method. After forming a polysilazane-containing film, it is baked by contacting with amines and water vapor at a low temperature of 0 ° C. to 100 ° C. for 0.1 seconds to 30 minutes and holding in a dry atmosphere at 200 ° C. or higher for 5 minutes or longer. Thus, a silica film is formed. In the previous low-temperature treatment, it is described that only about 30% is made into a silica film and converted into a complete silica film in a subsequent drying step. Further, the firing temperature is preferably 350 to 450 ° C. or higher, and is preferably maintained for 30 minutes or longer.

Patent Document 4 discloses a method for forming ceramics at a low temperature. The polysilazane-containing film is heat-treated at a temperature of 150 ° C. or lower, and then heat-treated in a saturated saturated steam atmosphere of 130 ° C. × 1 h at 2.66 atm to form a silica film. In the previous heat treatment, the silica film is not completely formed, but in the subsequent heat treatment, the silica film is completely formed.
Instead of the subsequent heat treatment, it may be immersed in distilled water containing the catalyst, and both of these two methods may be performed. For example, when hydrochloric acid is used as the catalyst, it is soaked at room temperature for 24 hours and then dried at 100 ° C. for 2 hours. Furthermore, the polysilazane-containing film may be brought into contact with Pd ²⁺ ions and water and heated to 90 ° C., and a silica film can be similarly formed.

However, at present, in order to form a dense silica film in a short time, it is necessary to heat to about 100 ° C. or more, and a long formation time of 1 hour or more is required. Therefore, there was a problem that the production efficiency of the silica film was poor and the production cost was high.
JP 7-45605 A JP 2003-347294 A Japanese Patent Laid-Open No. 10-194753 Japanese Patent Application Laid-Open No. 07-223867

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a dense silica film in a short time by a simple operation and without affecting the base material.

In order to achieve the above object, the present invention employs the following configuration. That is,
The method for forming a silica film of the present invention includes a step of forming a polysilazane-containing film on the surface of a substrate, a step of blowing a carrier gas that has passed through an atmospheric pressure plasma region to the polysilazane-containing film, and converting the film into a silica film, It is characterized by having.

  In the method for forming a silica film of the present invention, the carrier gas contains one or more of oxygen gas, nitrogen gas, and hydrogen gas in a carrier gas with respect to either a rare gas or a nitrogen gas. It is characterized by being made to contain in the density | concentration of 0.01-40 volume%

  The method for forming a silica film of the present invention is characterized in that the step of converting into a silica film is performed in an atmosphere containing hydrogen peroxide.

  The method for forming a silica film of the present invention includes a pretreatment step of blowing a carrier gas that has passed through an atmospheric pressure plasma region before forming the polysilazane-containing film.

  The method for forming a silica film of the present invention includes a post-treatment step of blowing a carrier gas that has passed through an atmospheric pressure plasma region after converting the polysilazane-containing film into the silica film.

  The method for forming a silica film of the present invention is characterized by having a post-treatment step of performing a heat treatment in a temperature atmosphere of 100 to 700 ° C. after converting the polysilazane-containing film into the silica film.

  The method for forming a silica film of the present invention is characterized by having a post-treatment step of performing a superheated steam treatment in a humidified temperature atmosphere at a temperature of 100 to 500 ° C. after converting the polysilazane-containing film to the silica film.

  The method for forming a silica film of the present invention includes a post-treatment step of performing ozone treatment after converting the polysilazane-containing film into the silica film.

  The method for forming a silica film of the present invention includes a post-treatment step of performing ultraviolet treatment of irradiating the silica film with ultraviolet rays of 10 to 200 nm after the polysilazane-containing film is converted into the silica film. To do.

  According to the above configuration, it is possible to provide a method for forming a dense and highly adherent silica film in a short time with a simple operation and without affecting the base material.

  The method for forming a silica film of the present invention comprises a step of forming a polysilazane-containing film on the surface of a substrate, and a step of blowing a carrier gas that has passed through the atmospheric pressure plasma region to the polysilazane-containing film to convert it into a silica film. With this configuration, it is not necessary to set the temperature high, and a dense silica film can be formed in a short time with a simple operation while the sample is kept in the atmosphere.

  In the method for forming a silica film of the present invention, the carrier gas contains one or more of oxygen gas, nitrogen gas, and hydrogen gas in the carrier gas with respect to either the rare gas or the nitrogen gas. Since the concentration is 0.01 to 40% by volume, radicals such as oxygen radicals, nitrogen radicals, and hydrogen radicals can be generated by passing through the atmospheric pressure plasma region. By spraying the contained carrier gas onto the polysilazane-containing film, it can be quickly converted into a silica film.

  In the method for forming a silica film of the present invention, since the step of converting to a silica film is performed in an atmosphere containing hydrogen peroxide, the conversion reaction is promoted, and the polysilazane-containing film is converted into a silica film in a very short time. Can be converted to

  The method for forming a silica film of the present invention has a pretreatment step of blowing a carrier gas that has passed through an atmospheric pressure plasma region before forming a polysilazane-containing film. Thus, the polysilazane-containing film can be uniformly formed.

  The method for forming a silica film according to the present invention comprises a post-treatment step of blowing a carrier gas that has passed through an atmospheric pressure plasma region after converting a polysilazane-containing film into a silica film, so that it is made hydrophilic in a very short time. be able to.

Hereinafter, modes for carrying out the present invention will be described.
(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing an example of a method for forming a silica film according to an embodiment of the present invention.
The method for producing a silica film of the present invention includes a step of forming the polysilazane-containing film 3 on the surface 1a of the substrate 1, and a carrier film P that has passed through the atmospheric pressure plasma region 10 is sprayed onto the polysilazane-containing film 3 to form the silica film 4 A step of converting to.

(Step of forming polysilazane-containing film 3)
As shown in FIG. 1A, after applying a coating liquid containing polysilazane and a solvent to the surface 1a of the substrate 1, the solvent is removed to form a polysilazane-containing film 3.

  The material of the substrate 1 is not particularly limited. For example, metals such as stainless steel and titanium, resins such as polycarbonate and acrylic resin, ceramics such as alumina and zirconia, minerals such as jewels, corals and fossils, bones, teeth, wood, paper, leather, silicon wafers, etc. it can.

Polysilazane (PolySilazane) is a compound having a bond “— (SiH ₂ —NH) —” (wherein all or part of H may be substituted with a substituent), and is a chain polysilazane or cyclic polysilazane. Etc.
Examples of the chain polysilazane include perhydropolysilazane, polymethylhydrosilazane, polyN-methylsilazane, polyN- (triethylsilyl) allylsilazane, polyN- (dimethylamino) cyclohexylsilazane, and phenylpolysilazane.
Any of these can be used and is not limited thereto. Polysilazane may be used alone or as a mixture of two or more.
In particular, perhydroxypolysilazane is preferable because it is easily available and has a good effect of forming a dense silica film.

The solvent may be any solvent that does not react with polysilazane and can form a uniform polysilazane solution.
For example, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene; aliphatic hydrocarbons such as pentane, hexane, isohexane, methylpentane, heptane, isoheptane, octane, isooctane; cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane Alicyclic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane, etc .; ethyl ether, isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, Examples thereof include ethers such as thiochitasan, dimethyldioxane, tetrahydrofuran, and tetrahydropyran.
These solvents may be one kind or a mixture of two or more kinds.

The polysilazane concentration in the coating solution is preferably 0.01 to 50% by mass, and more preferably 1 to 20% by mass.
A catalyst may be added to the coating liquid. Examples of the catalyst include triethylamine, diethylamine, monoethanolamine, diethanolamine, n-butylamine, di-n-butylamine, tri-n-butylamine and other amines, sodium hydroxide, potassium hydroxide and other metal hydroxides, ammonia Water, bases such as pyridine, acetic acid, acetic anhydride, succinic acid, fumaric acid, maleic acid, maleic anhydride, carboxylic acids such as succinic acid and their anhydrides, organic acids such as trichloroacetic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. Inorganic acids, and Lewis acids such as iron trichloride and aluminum trichloride.
Furthermore, an appropriate additive can be contained in the coating liquid according to the purpose within a range not impairing the effects of the present invention. Examples of the additive include an ultraviolet absorber, a filler made of ceramics or resin, a fluorine compound, a drug component, a photocatalyst, a photosensitive component, a brightener, and the like.
Specifically, it is made of calcium compounds for bioactive membranes, zinc oxide and silver for antibacterial action, titanium dioxide and zinc oxide for ultraviolet blocking, molybdenum disulfide, tungsten disulfide, fluororesin particles for slidability. is there.

  As a method for applying the coating liquid, a brush coating method, a spray method, a dipping method, a flow coating method, or the like can be used. Further, prior to application of the coating liquid, the coated surface may be polished or washed as necessary. Furthermore, after applying the coating liquid, it is preferable to perform a drying step in order to remove the solvent.

(Process of converting polysilazane-containing film to silica film)
Next, as shown in FIG. 1B, by blowing the carrier gas P that has passed through the atmospheric pressure plasma region onto the surface 3a of the polysilazane-containing film 3, as shown in FIG. To convert.
The carrier gas includes a rare gas such as helium, argon, xenon, neon, and krypton, and a discharge gas such as nitrogen, air, hydrogen, and oxygen. The discharge gas is a gas that can cause a discharge by applying a voltage, and may be used alone or in combination. The carrier gas may contain gases such as ozone, carbon dioxide, carbon monoxide, and ammonia in addition to the discharge gas. These gases have a function of promoting the reaction and may be sprayed on the polysilazane-containing film.
The carrier gas is preferably a combination of either a rare gas or nitrogen and one or more of oxygen, nitrogen or hydrogen, a combination of a rare gas and oxygen, nitrogen or hydrogen, nitrogen and A combination with oxygen or hydrogen is particularly preferred. The concentration of oxygen, nitrogen or hydrogen in the carrier gas in the case of a combination of a rare gas and oxygen, nitrogen or hydrogen, and the concentration of oxygen or hydrogen in the carrier gas in the case of a combination of nitrogen and oxygen or hydrogen is 0.01 -40% by volume is preferable, 0.05-20% by volume is more preferable, and 0.1-10% by volume is particularly preferable.

FIG. 2 is a schematic cross-sectional view of a remote type (blowing type) discharge tube 14 which is an example of a plasma apparatus used in the present invention. By passing the carrier gas G through the remote type (blowing type) discharge tube 14, the carrier gas P that has passed through the atmospheric pressure plasma region 10 can be generated and sprayed onto the surface 3 a of the polysilazane-containing film 3.
The substrate 1 is arranged so that the carrier gas P ejected from the carrier gas ejection port 17 is sprayed onto the surface 3 a of the polysilazane-containing film 3.

  A carrier gas inlet 16 is provided at one end side 14 a of the remote type (blowing type) discharge tube 14, and a carrier gas outlet 17 is provided at the other end side 14 b. The carrier gas G injected from the carrier gas injection port 16 is injected into the through hole 14 c inside the remote type (blowing type) discharge tube 14 after dust and the like are removed by the glass filter 24. The carrier gas that has passed through the through hole 14 c is ejected from the carrier gas ejection port 17.

The inner wall of the through hole 14 c is surrounded by the dielectric 22. Further, two electrodes 20 and 21 are provided so as to cover the dielectric 22, and a discharge part 15 is formed. By applying a voltage to the two electrodes 20 and 21, the atmospheric pressure plasma region 10 is formed in the discharge portion 15. At this time, the cooling water 26 is poured to cool the discharge part 15.
In this way, the carrier gas G is the carrier gas P that has passed through the atmospheric pressure plasma region 10.

  By blowing this carrier gas P onto the polysilazane-containing film 3, for example, a silica film 4 having a thickness of about 0.01 to 2 μm can be formed.

It is said that polysilazane reacts with water (H ₂ O) and is converted into a silica film as represented by the following reaction formula (1).
(—SiH ₂ —NH —) + 2H ₂ O → (—SiO ₂ —) + NH ₃ + 2H ₂ (1)
In the present invention, since the carrier gas P that has generated radicals by passing through the atmospheric pressure plasma region 10 is sprayed onto the polysilazane-containing film 3, this radical reacts with the polysilazane-containing film, and in a short time the polysilazane-containing film 3 It is presumed that can be converted into a silica film 4.

If the carrier gas P is sprayed onto the polysilazane-containing film 3 in an atmosphere such as water, ethanol, peracetic acid, or hydrogen peroxide solution, the effect of promoting the conversion reaction is great. The effect of promoting the conversion reaction is remarkable. Thus, liquids such as water, ethanol, peracetic acid, and hydrogen peroxide have an action of promoting the conversion reaction.
The above-mentioned “performed in the atmosphere” means, for example, that the carrier gas P that has passed through the atmospheric pressure plasma region 10 after the layer made of these liquids is formed on the polysilazane-containing film 3 is sprayed onto the polysilazane-containing film 3. By spraying the carrier gas P that has passed through the atmospheric pressure plasma region 10 in a state of spraying the liquid, onto the polysilazane-containing film 3, or by passing the carrier gas G containing these liquids through the atmospheric pressure plasma region 10, The carrier gas P containing these liquids is used by spraying on the polysilazane-containing film 3.
A carrier gas P which has been formed on the polysilazane-containing film and then passed through the atmospheric pressure plasma region 10 is sprayed onto the polysilazane-containing film 3 or the atmospheric pressure plasma region 10 is sprayed with these liquids. A method of spraying the carrier gas P that has passed through the polysilazane-containing film 3 is preferable, and the carrier gas P that has passed through the atmospheric pressure plasma region 10 after the layer made of these liquids is formed on the polysilazane-containing film 3 The method of spraying on the film 3 is particularly preferable.

In addition, the present invention includes heat treatment (100 to 700 ° C., 5 to 60 minutes), superheated steam treatment (100 to 500 ° C., 5 to 60 minutes), ozone treatment, ultraviolet treatment (10 to 200 nm, 5 to 60 minutes). It is also possible to carry out in combination with a treatment such as UV treatment, and a combination with ultraviolet treatment is particularly preferred.
Furthermore, if a plurality of plasma apparatuses used in the present invention are used, it is possible to process the substrate 1 having a large area. By combining apparatuses with different conditions such as using different carrier gases, processing according to the purpose is possible. It is.

In addition, as for the silica film 4 which is embodiment of this invention, all the polysilazanes contained in the polysilazane containing film | membrane 3 may not be converted into a silica, but only a part may be converted into the silica.
For example, when the spraying time of the carrier gas P that has passed through the atmospheric pressure plasma region 10 is short or when the energy density of the atmospheric pressure plasma is small, the conversion to silica is incomplete, and the surface of the formed silica film 4 is formed. OH groups may remain. Thus, the silica film 4 having an OH group on the surface is useful because it can be used, for example, as a bonding film between a silane coupling agent and a substrate. For example, when a dental restoration material (ceramic material) is bonded to the surface 4a of the silica film 4 via a silane coupling agent or an adhesive, the adhesion between the silica film 4 and the silane coupling agent can be increased. .

(Embodiment 2)
FIG. 3 is a schematic cross-sectional view showing another example of a method for forming a silica film according to an embodiment of the present invention.
The method for producing a silica film according to an embodiment of the present invention is an example in which the carrier gas P is sprayed on the polysilazane-containing film 3 in a hydrogen peroxide solution atmosphere. The configuration is the same as that of the first embodiment except that the step of forming is included. In addition, about the member same as Embodiment 1, it attaches | subjects and shows the same code | symbol.

(Polysilazane-containing film formation process)
First, as shown in FIG. 3A, a polysilazane-containing film 3 is formed in the same manner as in the first embodiment.
Next, as shown in FIG. 3B, a hydrogen peroxide solution layer 5 is formed on the surface 3a of the polysilazane-containing film 3 by dropping hydrogen peroxide solution.
The film thickness of the hydrogen peroxide solution layer 5 is not particularly limited as long as it covers the surface 3 a of the polysilazane-containing film 3. The concentration of hydrogen peroxide in the hydrogen peroxide aqueous layer 5 is preferably 0.1 to 30% by mass, and more preferably 1 to 5% by mass. By setting the concentration within this range, the reaction in the silica film conversion step can be performed more rapidly.
The hydrogen peroxide solution is water (H ₂ O) containing hydrogen peroxide (H ₂ O ₂ ). In addition, when a surfactant is contained in the hydrogen peroxide solution, a more uniform hydrogen peroxide solution layer 5 can be formed, which is preferable in forming a ceramic film with good film quality.

(Silica membrane conversion process)
Next, as shown in FIG. 3C, by blowing the carrier gas P that has passed through the atmospheric pressure plasma region 10 onto the surface 5a of the hydrogen peroxide solution layer 5, as shown in FIG. In a few seconds, for example, the silica film 4 having a film thickness of about 0.01 to 2 μm can be formed.

  By using the carrier gas P that has passed through the atmospheric pressure plasma region 10 and the hydrogen peroxide solution layer 5 in combination, the polysilazane-containing film 3 can be converted into the silica film 4 in a very short time. This is presumed to be because radicals generated in the atmospheric pressure plasma region 10 react with the hydrogen peroxide solution to generate more active radicals.

  In addition, when spraying the carrier gas P onto the polysilazane-containing film 3, as a method for performing the conversion reaction in a hydrogen peroxide atmosphere, a state in which hydrogen peroxide solution is sprayed instead of forming the hydrogen peroxide solution layer 5 is used. Even if the carrier gas P that has passed through the atmospheric pressure plasma region 10 is sprayed onto the polysilazane-containing film 3, the carrier gas P that has been mixed with hydrogen peroxide is passed through the atmospheric pressure plasma region 10 to form the polysilazane-containing film. 3 may be sprayed.

  The hydrogen peroxide solution may be sprayed from the carrier gas inlet 16 on the one end side 14a of the remote type (blowing type) discharge tube 14. Furthermore, a hydrogen peroxide solution inlet may be provided inside the through hole 14c so that the hydrogen peroxide solution is sprayed into the through hole 14c.

  Further, OH groups in the surface of the silica film 4 or on the surface can be easily detached and removed by performing post-treatment such as annealing. By removing the OH group to form a denser film, for example, it can be used as an insulating film of a semiconductor device. Further, it can be used as a dense film that prevents permeation of gas and ions.

(Embodiment 3)
Embodiment 1 is the same as Embodiment 1 except that the pretreatment step of cleaning the surface of the substrate by spraying the surface 1a of the substrate 1 with the carrier gas P that has passed through the atmospheric pressure plasma region 10 is performed before the polysilazane-containing film forming step. Similarly, a silica film 4 was formed.
The base material 1 is arranged so that the carrier gas P ejected from the carrier gas ejection port 17 of the remote type (blowing type) discharge tube 14 is sprayed onto the surface 1 a of the base material 1.

  By spraying the carrier gas P onto the base material 1 in the same manner as in the first embodiment, for example, organic substances remaining on the surface 1a of the base material 1 can be removed and cleaned in a few seconds. Further, the wettability of the surface 1a of the substrate 1 can be improved and the polysilazane-containing film 3 can be formed uniformly.

(Embodiment 4)
After the polysilazane-containing film 3 is converted to the silica film 4, the carrier gas P that has passed through the atmospheric pressure plasma region 10 is sprayed onto the surface 4 a of the silica film 4 to reduce the OH groups contained in the silica film 4. A silica film 4 was formed in the same manner as in Embodiment 1 except that the steps were performed.
The substrate 1 is disposed so that the carrier gas P ejected from the carrier gas ejection port 17 of the remote type (blowing type) discharge tube 14 is sprayed onto the surface 4 a of the silica film 4.

  In the same manner as in the first embodiment, the carrier gas P is sprayed onto the surface 4a of the silica film 4 to remove, for example, OH groups remaining in the silica film 4 in a few seconds, thereby insulating and dense the silica film 4. Can be improved.

In addition, as a post-treatment process, heat treatment (100 to 700 ° C., 5 to 60 minutes), superheated steam treatment (100 to 500 ° C., 5 to 60 minutes), ozone treatment, ultraviolet treatment (10 to 200 nm, 5 to 60) Or a post-treatment step of spraying the carrier gas P that has passed through the atmospheric pressure plasma region 10 onto the surface 4a of the silica film 4 may be used. Good. A post-treatment that combines a post-treatment step of spraying the carrier gas P that has passed through the atmospheric pressure plasma region 10 onto the surface 4a of the silica film 4 and an ultraviolet treatment is particularly preferred.
The carrier gas P that has passed through the atmospheric pressure plasma region 10 is sprayed onto the surface 4a of the silica film 4 to reduce the OH groups contained in the silica film 4, and the OH groups remaining in the silica film 4 are substantially the same as in the post-treatment process. Can be removed.

  The method for forming a silica film 4 according to an embodiment of the present invention includes a step of forming a polysilazane-containing film 3 containing polysilazane on the surface 1a of the substrate 1, and a carrier gas P that has passed through the atmospheric pressure plasma region 10 containing polysilazane. The step of spraying the membrane 3 to convert it to the silica membrane 4 does not require a high temperature, and the dense silica membrane 4 can be formed in a short time with a simple operation while keeping the sample in the atmosphere. Can be formed. Further, the temperature of the base material hardly rises even after the treatment is completed, and there is no need to worry about the occurrence of cracks that are a problem in high temperature treatment.

  In the method for forming the silica film 4 according to the embodiment of the present invention, the carrier gas G is either a rare gas or a nitrogen gas, and one or more of oxygen gas, nitrogen gas, or hydrogen gas is used. Is contained in the carrier gas at a concentration of 0.01 to 40% by volume. By passing through the atmospheric pressure plasma region 10, radicals such as oxygen radicals and nitrogen radicals can be generated. By spraying the carrier gas P containing the radicals onto the polysilazane-containing film 3, it can be quickly converted into the silica film 4.

  In the method for forming the silica film 4 according to the embodiment of the present invention, since the process of converting to the silica film 4 is performed in an atmosphere containing hydrogen peroxide solution, the conversion reaction is promoted and the process is performed in a very short time. The polysilazane-containing film 3 can be converted into a silica film 4.

  Since the method for forming the silica film 4 according to the embodiment of the present invention includes a pretreatment step of blowing the carrier gas P that has passed through the atmospheric pressure plasma region 10 before the polysilazane-containing film 3 is formed, While removing the organic substance on the surface 1a, the wettability of the surface 1a of the substrate 1 can be improved, and the polysilazane-containing film 3 can be formed uniformly.

  Since the method for forming the silica film 4 according to the embodiment of the present invention has a post-treatment process in which the polysilazane-containing film 3 is converted into the silica film 4 and then the carrier gas P that has passed through the atmospheric pressure plasma region 10 is sprayed. The OH groups remaining in the silica film 4 can be removed in a very short time, and the insulating properties of the silica film 4 can be improved.

  Since the method for forming the silica film 4 according to the embodiment of the present invention includes a post-treatment process in which the polysilazane-containing film 3 is converted into the silica film 4 and then heat treatment is performed in a temperature atmosphere of 100 to 700 ° C. The OH groups remaining in the film 4 can be removed, and the insulating properties and denseness of the silica film 4 can be improved.

  The method for forming the silica film 4 according to the embodiment of the present invention includes a post-treatment process in which the polysilazane-containing film 3 is converted into the silica film 4 and then subjected to a superheated steam treatment in a humidified temperature atmosphere at a temperature of 100 to 500 ° C. Therefore, the OH group remaining in the silica film 4 can be removed, and the insulating properties and denseness of the silica film 4 can be improved.

  Since the method for forming the silica film 4 according to the embodiment of the present invention has a post-treatment process in which the polysilazane-containing film 3 is converted into the silica film 4 and then ozone treatment is performed, OH groups remaining in the silica film 4 are removed. It can be removed, and the insulating properties and denseness of the silica film 4 can be improved.

The method for forming the silica film 4 according to the embodiment of the present invention includes a post-treatment process in which after the polysilazane-containing film 3 is converted into the silica film 4, ultraviolet treatment is performed by irradiating the silica film 4 with ultraviolet rays of 10 to 200 nm. With this configuration, OH groups remaining in the silica film 4 can be removed in a very short time, and the insulating properties of the silica film 4 can be improved.
Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited only to these examples.

Example 1
After applying 5% NL120 (manufactured by AZ Electronic Materials Co., Ltd.) as perhydroxypolysilazane on a silicon wafer, this was dried to obtain a polysilazane-containing film sample of Example 1.
Next, Ar gas containing 7% by volume of O ₂ gas was supplied at 1000 sccm, and the carrier gas passed through the atmospheric pressure plasma region using the atmospheric pressure plasma device manufactured by NU Eco-Engineering was used as Example 1 Polysilazane The containing membrane sample was sprayed for 5 seconds to form a silica membrane sample of Example 1.

Next, the transmission FTIR spectrum of the silica membrane sample of Example 1 was measured.
Transmissive FTIR spectra, Fourier transform infrared spectrophotometer (manufactured by Shimadzu Corporation, product name: SHIMADZU IR Prestige-21) using a wave number range of about 4500～650Cm ^-1 at ATR method, resolution ^{4 cm -1,} accumulating The number of measurements was 50.

FIG. 4 is a transmission FTIR spectrum of the silica membrane sample of Example 1.
An absorption peak attributable to SiO near 1060 cm ^-1 and near 800 cm ^-1 indicative of silica conversion, absorption peaks of SiH attributable near SiN and 2170 cm ^-1 in the vicinity of 830 cm ^-1 indicating the remaining PHPS unreacted Were compared to evaluate the conversion into a silica film.
Example 1 As shown in the transmission FTIR spectrum of the silica film sample, a large SiO peak of 1064 cm ⁻¹ appeared, indicating that a silica film was formed. However, since the SiH peak of unreacted SiN peaks and 2243cm ^-1 unreacted 831cm ^-1 is observed, it was found that a part of which is converted into silica film.

(Example 2)
A silica film sample of Example 2 was formed in the same manner as in Example 1 except that the blowing time of the carrier gas that passed through the atmospheric pressure region was 1 minute.

FIG. 5 is a transmission FTIR spectrum of the silica membrane sample of Example 2.
As shown in transmission FTIR spectra of Example 2 silica film samples, 1060 cm SiO peak around ^-1 appeared greater than 2, the unreacted SiH near SiN peak and 2170 cm ^-1 unreacted around 830 cm ^-1 The peak was smaller than in FIG. Therefore, it was found that the polysilazane-containing film was converted to a silica film from Example 1.

(Example 3)
Example 3 A silica film sample was formed in the same manner as in Example 1 except that hydrogen peroxide solution (hydrogen peroxide concentration 3%) was dropped to form a hydrogen peroxide solution layer on the polysilazane-containing film. .

FIG. 6 is a transmission FTIR spectrum of the silica membrane sample of Example 3.
As shown in transmission FTIR spectra of Example 3 silica film samples appear larger SiO peak of 1070 cm ^-1, unreacted SiH peak around SiN peak and 2170 cm ^-1 unreacted 792cm ^-1 was nearly gone . Therefore, it was found that the polysilazane-containing film was almost converted into a silica film. That is, the polysilazane-containing film could be converted to a silica film by treatment at room temperature for 5 seconds and at a very short time.

(Comparative Example 1)
NL120 (manufactured by AZ Electronic Materials Co., Ltd.) 5% was applied to the silicon wafer as perhydroxypolysilazane and dried to form a comparative example 1 polysilazane-containing film sample.

(Comparative Example 2)
NL120 (manufactured by AZ Electronic Materials Co., Ltd.) 5% was applied to the silicon wafer as perhydroxypolysilazane and dried to form a polysilazane film. A hydrogen peroxide solution (hydrogen peroxide concentration: 3%) was dropped onto the polysilazane film, left at room temperature for 1 minute, and dried at room temperature to form a comparative example 2 polysilazane-containing film sample.
FIG. 7 shows transmission FTIR spectra of the polysilazane-containing film samples of Comparative Example 1 and Comparative Example 2. The transmission FTIR spectra of the polysilazane-containing film samples of Comparative Example 1 and Comparative Example 2 were the same chart.
As shown in transmission FTIR spectrum of the polysilazane-containing film samples of Comparative Examples 1 and 2, 1060 cm SiO peak around ^-1 hardly observed, 830 cm unreacted around ^-1 SiN peak and 2170 cm ^-1 A large unreacted SiH peak was observed in the vicinity. That is, only by applying perhydroxypolysilazane and drying, or after applying perhydroxypolysilazane and drying, and then leaving it for 1 minute at room temperature with hydrogen peroxide solution dropped, only a polysilazane-containing film is formed. The silica film was not formed at all.

The present invention relates to a method for forming a silica film. Since the silica film can be formed at room temperature in a short time, the present invention can be used in the medical member-related industry or the semiconductor industry.
For example, when plastic is used as the base material, it can be used for bathroom products such as toilets, bathtubs, syringes, pipettes, cups, plastic bottles, dentures, etc. When metal is used as the base material, cars and trains It can be used for aircraft bodies, window glass, containers, piping, pumps, fans, ornaments, etc. Furthermore, when used for a semiconductor wafer, it can be used for an interlayer insulating film or the like, and can also be used for human teeth.

It is a cross-sectional schematic diagram which shows an example of the formation method of the silica film which is embodiment of this invention. It is a cross-sectional schematic diagram of the remote type | mold (blowing type | mold) discharge tube used with the formation method of the silica film which is embodiment of this invention. It is a cross-sectional schematic diagram which shows another example of the formation method of the silica film which is embodiment of this invention. It is a FTIR graph of the silica film formed with the formation method of the silica film which is an embodiment of the present invention. It is a FTIR graph of the silica film formed with the formation method of the silica film which is an embodiment of the present invention. It is a FTIR graph of the silica film formed with the formation method of the silica film which is an embodiment of the present invention. It is a FTIR graph of the film | membrane formed as a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material, 1a ... Surface, 3 ... Polysilazane containing film, 3a ... Surface, 4 ... Silica film, 5 ... Hydrogen peroxide water layer, 5a ... Surface, 10 ... Atmospheric pressure plasma area, 14 ... Remote type (blowing type) ) Discharge tube, 14a ... one end side, 14b ... other end side, 14c ... through hole, 15 ... discharge part, 16 ... carrier gas injection port, 17 ... carrier gas injection port, 20, 21 ... electrode, 22 ... dielectric, 24 ... Glass filter, 26 ... Cooling water, P ... Carrier gas passed through atmospheric pressure plasma region.

Claims (9)

  A step of forming a polysilazane-containing film on the surface of the substrate, and a step of blowing a carrier gas that has passed through an atmospheric pressure plasma region onto the polysilazane-containing film to convert it into a silica film. Forming method.   The carrier gas is one or more of oxygen gas, nitrogen gas or hydrogen gas with respect to any gas of rare gas or nitrogen gas, and the concentration in the carrier gas is 0.01 to 40% by volume. The method for forming a silica film according to claim 1, comprising:   The method for forming a silica film according to claim 1, wherein the step of converting to a silica film is performed in an atmosphere containing hydrogen peroxide.   The method for forming a silica film according to any one of claims 1 to 3, further comprising a pretreatment step of blowing a carrier gas that has passed through an atmospheric pressure plasma region before forming the polysilazane-containing film. .   The silica according to any one of claims 1 to 4, further comprising a post-treatment step of spraying a carrier gas that has passed through an atmospheric pressure plasma region after the polysilazane-containing film is converted into the silica film. Method for forming a film.   5. The silica according to claim 1, further comprising a post-treatment step of performing a heat treatment in a temperature atmosphere of 100 to 700 ° C. after converting the polysilazane-containing film into the silica film. Method for forming a film.   5. The method according to claim 1, further comprising a post-treatment step of performing a superheated steam treatment in a humidified atmosphere at a temperature of 100 to 500 ° C. after the polysilazane-containing film is converted into the silica film. A method for forming a silica film as described.   5. The method for forming a silica film according to claim 1, further comprising a post-treatment step of performing ozone treatment after the polysilazane-containing film is converted into the silica film.   5. The method according to claim 1, further comprising a post-treatment step of performing ultraviolet treatment of irradiating the silica film with ultraviolet rays of 10 to 200 nm after the polysilazane-containing film is converted into the silica film. The method for forming a silica film according to Item.

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