JP2012149278A - Method for producing silicon-containing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silicon-containing film which shows high steam barrier property and heat and moisture resistance.SOLUTION: The method for producing a silicon-containing film includes: depositing a dry deposited film including at least silicon atom and nitrogen atom on a substrate by a dry method, and then modifying at least part of the film by irradiating the film surface with light having a wavelength of 150 nm or less. The method is suitably used for a dry deposited film including hydrogen derived from at least Si-H bond or N-H bond, which is formed by a means selected from among vapor deposition, reactive vapor deposition, sputtering, reactive sputtering, and chemical vapor deposition.

Description

The present invention relates to a method for manufacturing a silicon-containing film.

  In recent years, transparent gas barrier films that block gases such as oxygen and water vapor have been used not only for packaging materials such as foods and pharmaceuticals, which are traditional main uses, but also for flat panel displays (FPD) such as liquid crystal displays and solar cells. It has come to be used also for such members (substrates, back sheets, etc.), flexible substrates for organic electroluminescent (organic EL) elements, sealing films, and the like. In such applications of electronic devices, very high gas barrier properties are required.

  As films having very high water vapor gas barrier properties, silicon nitride films, silicon oxynitride films, and the like are known. A dry method is often used for forming these films. In particular, the chemical vapor deposition (CVD) method is one of the promising film forming methods of the dry method. For example, a catalytic chemical vapor deposition (Cat-CVD) method (Patent Document 1) and a plasma chemical vapor deposition (PECVD) method (Patent Documents 2 to 4) are known.

  For example, in silicon nitride film formation, various CVD methods can be used to reduce H derived from Si—H bonds and N—H bonds in the film in order to provide high gas barrier properties, oxidation resistance, and heat and moisture resistance. It has become a common issue in law. In any CVD method, it is considered that the above-mentioned problems are solved by activating a chemical reaction that deposits a film and simultaneously removes H derived from Si—H bonds and N—H bonds from the surface of the film. It is done.

  Patent Document 1 discloses a method of adding a large amount of hydrogen gas to a material gas containing silicon or nitrogen when silicon nitride is formed by Cat-CVD.

  Patent Document 2 discloses a technique in which a large amount of silane gas is diluted with nitrogen gas, which is a nitrogen source not containing hydrogen, by PECVD using inductively coupled plasma.

  Patent Document 3 discloses a technique of adding a large amount of rare gas to a material gas containing silicon or nitrogen by PECVD using the same inductively coupled plasma as Patent Document 2.

  Patent Document 4 discloses a technique in which a film formation temperature is set to 300 to 600 ° C. in a gas system in which hydrogen gas is added to a material gas containing silicon or nitrogen by a PECVD method using microwave excitation plasma. .

JP 2004-292877 A JP 2005-079254 A JP 2009-246129 A JP 2009-084585 A JP-A-2-113521

E. D. Palik ed .: “Handbook of Optical Constants of Solids” (1985) pages 749-763 and 771-774 Appl. Phys. Lett., 65 (1994), 2229-2231

  However, in order to obtain high water vapor gas barrier properties, oxidation resistance, and heat-and-moisture resistance with these CVD films, a large amount of hydrogen or inert gas is added to reduce the concentration of the material gas containing silicon or nitrogen to suppress the film formation rate. The film forming conditions with low productivity were selected. Further, increasing the substrate temperature is an important condition for obtaining high gas barrier properties and moisture resistance, but the usable substrates are limited. In view of the above situation, an object of the present invention is to provide a method for producing a silicon-containing film exhibiting high water vapor barrier properties and moisture and heat resistance.

As a result of intensive studies on a method for obtaining a film exhibiting high water vapor barrier properties and wet heat resistance by an approach different from the above method, the present inventors have found a new method and have reached the present invention.
The present invention is shown below.

[1] A silicon-containing film comprising a step of depositing a dry deposition film containing at least silicon atoms and nitrogen atoms on a substrate by a dry method and then irradiating the film surface with light having a wavelength of 150 nm or less. Manufacturing method.
[2] The method for producing a silicon-containing film according to [1], wherein the dry deposition film is a film containing at least H derived from an Si—H bond or an N—H bond.
[3] As described in [1] to [2], the dry method is a method selected from a vapor deposition method, a reactive vapor deposition method, a sputtering method, a reactive sputtering method, and a chemical vapor deposition method. A method for producing a silicon-containing film.
[4] The method for producing a silicon-containing film according to [1] to [2], wherein the dry method is a catalytic chemical vapor deposition method or a plasma chemical vapor deposition method.
[5] The method for producing a silicon-containing film according to any one of [1] to [4], wherein the light irradiation with the wavelength of 150 nm or less is performed by plasma treatment.
[6] The plasma treatment includes helium, neon, argon, a mixed gas of helium and hydrogen, a mixed gas of neon and hydrogen, a mixed gas of argon and hydrogen, a mixed gas of helium and nitrogen, a mixed gas of neon and nitrogen, and argon. The method for producing a silicon-containing film according to [5], which is performed in a pressure atmosphere of 0.1 Pa or more and 100 Pa or less in the presence of an atmosphere gas selected from nitrogen and nitrogen.
[7] The method for producing a silicon-containing film according to [1] to [6], wherein the substrate is heated to 25 ° C. to 1000 ° C. simultaneously with light irradiation with the wavelength of 150 nm or less.
[8] A laminate in which a silicon-containing film is formed on a substrate by the method according to [1] to [7].

According to the present invention, a method for producing a silicon-containing film exhibiting high water vapor barrier properties and wet heat resistance is provided. While depositing a film as seen in the CVD method, this technique is completely different from the technique for removing H derived from Si—H bonds and N—H bonds in the film, and can efficiently remove H. Provide a method. As a result, more dense Si—N—Si bonds that form the basis of the Si ₃ N ₄ structure are formed in the modified region. That is, the modified region exhibits high water vapor barrier properties and wet heat resistance. Therefore, according to the present invention, it is possible to further improve the water vapor barrier property and wet heat resistance of the dry deposition film.

  Further, in the dry film forming process, it is not necessary to select a film forming condition exhibiting high water vapor barrier properties and heat and moisture resistance, and therefore it is not always necessary to deposit a dense film. It is possible to select conditions that do not cause defects or irregularities in the film due to grain boundaries that occur when depositing a dense film, or conditions with a high film forming speed, giving the degree of freedom of film forming conditions for dry deposition films, Contributes to further improvement in performance and productivity of deposited films.

It is process sectional drawing which shows the manufacturing method of the silicon containing film of this embodiment.

FIG. 1 is a process cross-sectional view of the method for producing a silicon-containing film of this embodiment.
(Silicon-containing film 16)
The silicon-containing film 16 is obtained by performing energy ray irradiation 10 on the main surface of the dry deposition film 14 deposited on the substrate 12 by a dry method. By this energy beam irradiation 10, a denatured region 18 is formed on the upper surface of the silicon-containing film 16 (over a predetermined depth from the surface). In the silicon-containing film 16, the region under the modified region 18, that is, between the modified region 18 and the substrate 12, is referred to as a slightly modified region 20 as a region that is not directly affected by energy irradiation. The silicon-containing film 16 includes a modified region 18 and a slightly modified region 20.

(Dry deposition film 14)
The dry deposition film 14 formed on the substrate 12 by the dry method contains at least silicon atoms and nitrogen atoms. Further, the film contains at least H derived from an Si—H bond or an N—H bond. The dry deposition film 14 is preferably mainly composed of silicon nitride containing hydrogen or silicon oxynitride containing hydrogen. The bonding state of atoms in the film is evaluated by measuring an FT-IR spectrum using an infrared visible spectroscopy (FT-IR) apparatus (for example, “FT / IR-300E”, manufactured by JASCO Corporation). it can. As shown in Non-Patent Document 2, N—H bonds have peaks near 1170 and 3350 cm ⁻¹ , and Si—H bonds have peaks near 2150 cm ⁻¹ .

  The Si—H bond and N—H bond in the film work effectively to maintain the flexibility of the film so that the film does not physically break, but on the other hand, the water vapor barrier property and moisture resistance of the film Detrimental to heat.

  In the present invention, by the following step (b), at least a part of the dry deposition film 14 is formed with a modified region 18 having an inclined structure in which the atomic composition of the film gradually changes, so that the high performance of the dry deposition film 14 is achieved. Can be achieved.

(Denatured region 18)
The modified region 18 includes at least silicon atoms and nitrogen atoms. The modified region 18 is composed of Si ₃ N ₄ , Si _x N _y , SiO _x N _y, or the like. The denatured region 18 is a region in which chemical bonds of constituent atoms are reconfigured by the energy irradiation 10, and is a region that bears the water vapor barrier property and the moisture and heat resistance performance of the silicon-containing film 16.

(Film thickness)
The film thickness (SiO ₂ equivalent film thickness) of the silicon-containing film 16 can be 20 nm to ₂ μm, preferably 100 nm to 1 μm. The modified region 18 may be formed on a part of the upper surface of the silicon-containing sealing film 16. Further, the modified region 18 may be formed over the entire silicon-containing film 16. In this case, the composition of the silicon-containing film 16 is the same as that of the modified region 18. Here, the film thickness of the modified region 18 is a region having a depth of 200 nm downward from the upper surface of the modified region 18, preferably a region having a depth of 100 nm downward from the upper surface.

<Method for Manufacturing Silicon-Containing Film 16>
The manufacturing method of the silicon-containing sealing film 16 of the present embodiment includes the following steps.
Step (a) A step of forming a film containing at least silicon atoms and nitrogen atoms on the substrate 12 by a dry method,
Step (b) A step of performing energy beam irradiation 10 on the dry deposition film 14 to form a silicon-containing film 16 including a modified region 18 formed on the upper surface.

In addition, there exists the following merit compared with a wet method by making a process (a) a dry method.
(A) If a film containing at least silicon atoms and nitrogen atoms is to be formed by a wet method, a step of coating the substrate 12 and a step of heating / drying it are required, which is a step compared to the dry method. Is complicated. Furthermore, when it is going to form the roll-shaped base material 12 into a film, a large-scale installation is required compared with the dry method.
(B) Since the film modification step in step (b) is a technique belonging to the dry method, it is compatible with the dry film forming method. In the dry film-forming method, it is easier to inline the process (a) and the process (b) than in the wet process.

[Step (a)]
In step (a), a film (dry deposition film 14) containing at least silicon atoms and nitrogen atoms is formed on the substrate 12 by a dry method.

(Substrate 12)
As the base material 12 to which the silicon-containing sealing film 16 of the present invention is applied, in addition to a metal substrate such as silicon, a glass substrate, a ceramic substrate, a resin substrate, a resin film, etc., a substrate in which a thin film is laminated, or a thin film deposition And a substrate on which elements and devices are formed by fine processing.

(Dry method)
The dry thin film deposition method used in the present invention is not particularly limited. Existing thin film deposition technology can be used. For example, there are a vapor deposition method, a reactive vapor deposition method, a sputtering method, a reactive sputtering method, a chemical vapor deposition method, and the like.

  The vapor deposition method is a method in which atoms / molecules evaporated from an evaporation source in a vacuum container are deposited on the substrate 12. The reactive vapor deposition method is a method in which a reactive gas is introduced into a vacuum vessel and atoms and molecules evaporated from the evaporation source are reacted and deposited, and an excitation source such as plasma is introduced to promote the reaction. You can also. As typical raw materials, silicon, silicon nitride, silicon oxide, silicon oxynitride, or the like is used as a deposition source, and nitrogen, hydrogen, ammonia, oxygen, or the like is used as a reactive gas.

The sputtering method is a method of depositing the constituent atoms of the sputtered target on the substrate 12 by utilizing a sputtering phenomenon in which high-energy ions accelerated by an electric field are incident on the target and the constituent atoms of the target are knocked out. The reactive sputtering method is a method in which a reactive gas is introduced into a vacuum vessel and reacted with constituent atoms of a sputtered target to be deposited on the substrate 12. As typical raw materials, silicon, silicon nitride, silicon oxide, silicon oxynitride or the like is used as a target material, and nitrogen, hydrogen, ammonia, oxygen or the like is used as a reactive gas.

In the chemical vapor deposition method, a material gas containing a constituent element of a film is introduced into a vacuum vessel, and the material gas is excited by a specific excitation source, thereby forming an excited species by a chemical reaction and depositing on the substrate 12. It is a method to make it. As typical raw materials, monosilane, hexamethyldisilazane, ammonia, nitrogen, hydrogen, oxygen and the like are used.
The chemical vapor deposition method is a more promising method because it can form a film at a high speed and has a better coverage with respect to the substrate 12 than a sputtering method or the like. In particular, a catalytic chemical vapor deposition (Cat-CVD) method using a very high temperature catalyst as an excitation source and a plasma chemical vapor deposition (PECVD) method using plasma as an excitation source are preferable methods. Hereinafter, these methods will be described in detail.

(Cat-CVD method)
In the Cat-CVD method, a material gas is allowed to flow into a vacuum vessel in which a wire made of tungsten or the like is disposed, and a material gas catalytic decomposition reaction is performed with a wire that is energized and heated by a power source. It is a method of depositing.

For example, when depositing silicon nitride, monosilane, ammonia, or hydrogen is used as the material gas. In the case of depositing silicon oxynitride, oxygen is added in addition to the above material gas. As a condition example, a tungsten wire (eg, Φ0.5 length: 2.8 m) as a catalyst body is heated to 1800 ° C., and monosilane, ammonia, and hydrogen (4/200/200 sccm) are circulated as material gases. The film is deposited on a substrate whose temperature is adjusted to 100 ° C. while maintaining the pressure at 10 Pa. Of the reactive species generated by the decomposition reaction on the catalyst body, the main deposition species are SiH ₃ ^* and NH ₂ ^* , and H ^* is a reaction auxiliary species on the film surface. In particular, it is believed that by adding hydrogen, a large amount of H * can be generated and the deposition rate is reduced, but the reaction for removing H derived from Si—H bonds and N—H bonds in the film is promoted. .

(PECVD method)
The PECVD method was generated by flowing a material gas into a vacuum vessel equipped with a plasma source, generating electric discharge plasma in the vacuum vessel by supplying power from the power source to the plasma source, and causing the material gas to decompose and react with the plasma. In this method, reactive species are deposited on the substrate 12. As a plasma source method, capacitively coupled plasma using parallel plate electrodes, inductively coupled plasma, microwave excitation plasma using surface waves, or the like is used.

When silicon nitride is deposited, monosilane, ammonia, nitrogen, or a rare gas or hydrogen is used as a gas for assisting the reaction as a material gas. In the case of depositing silicon oxynitride, oxygen is added in addition to the above material gas.
For example, when using inductively coupled plasma, an external antenna type low-pressure inductively coupled plasma CVD apparatus in which an antenna coil is installed in a vacuum vessel via a dielectric window is used. As a condition example, monosilane, ammonia, and helium (eg, 50/150/300 sccm) are circulated as gas species, and the pressure is maintained at 5 Pa. A plasma is formed by applying a high-frequency power of 2 kW to the antenna coil, and a film is deposited on the substrate adjusted to 70 ° C.

[Step (b)]
In step (b), the dry deposition film 14 is irradiated with high energy rays 10 to form a silicon-containing film 16. The energy ray irradiation treatment is preferably performed in an atmosphere substantially free of oxygen or water vapor.
The “atmosphere substantially free of oxygen or water vapor” means that oxygen and / or water vapor is not present at all, or the oxygen concentration is 0.5% (5000 ppm) or less, preferably 0.05% (500 ppm). ), More preferably, the oxygen concentration is 0.005% (50 ppm) or less, more preferably, the oxygen concentration is 0.002% (20 ppm) or less, more preferably 0.0002% (2 ppm) or less, or relative It refers to an atmosphere having a humidity of 0.5% or less, preferably a relative humidity of 0.2% or less, more preferably a relative humidity of 0.1% or less, and more preferably a relative humidity of 0.05% or less. The water vapor concentration (water vapor partial pressure / atmospheric pressure at room temperature 23 ° C.) is 140 ppm or less, more preferably 56 ppm, further preferably 28 ppm, and further preferably 14 ppm or less.

(Energy beam irradiation treatment)
The energy beam irradiation treatment in the present invention is characterized by performing light irradiation of 150 nm or less. Light irradiation with a wavelength in the range of 30 to 150 nm is more preferable. As a light irradiation method having a wavelength of 150 nm or less, plasma treatment capable of directly irradiating all vacuum ultraviolet light generated by plasma is preferable. The reasons are as follows (A) to (C).

(A) The dry deposition film 14 that performs the energy beam irradiation 10 is a film containing at least silicon atoms and nitrogen atoms, and the modified regions 18 formed by the energy beam irradiation process are Si ₃ N ₄ , Si _x N _y. , SiO _x N _{y and the} like. As shown in Non-Patent Document 1, the light absorption coefficient of amorphous SiO ₂ or amorphous Si ₃ N ₄ becomes very large in a wavelength region of 30 to 150 nm or less. The light absorption coefficient of 14 is also very large, the penetration of light becomes very shallow, and the modified layer 18 is also thought to be thin. Light irradiation in this wavelength region requires a smaller amount of energy rays necessary for modification because the number of atoms related to modification is reduced as the light penetration depth is smaller. That is, it is suitable for high-speed processing. On the other hand, light irradiation with a wavelength of 30 nm or less and 150 nm or more is considered to increase the penetration depth of light into the dry deposition film 14, and the number of atoms related to modification increases. An increase in irradiation dose is caused, which is not preferable.

(B) The shorter the wavelength of light, the higher the energy of photons, which are light quanta. Although the detailed photoreaction process is unknown, high-energy photons are absorbed by the dry deposition film 14 to create an excited state, which leads to breaking of various chemical bonds. Thereby, in the process of reorganization of the chemical bond in the modified region 18, H derived from the Si—H bond or N—H bond of the dry deposition film 14 is efficiently removed out of the film, and the Si ₃ N ₄ structure is formed. It is considered that more dense Si—N—Si bonds that are the basis of the above are formed in the modified region 18. That is, the modified region 18 exhibits high water vapor barrier properties and wet heat resistance.

(C) The light irradiation method with a wavelength of 150 nm or less includes light irradiation using a lamp unit in addition to the plasma treatment. In the method using the lamp unit, light having a central wavelength of 150 nm or less is taken out through the window material and irradiated to the dry deposition film 14. With light of this wavelength, light absorption and light deterioration of the window material occur remarkably, so that it is difficult to irradiate the dry deposition film 14 with high intensity light. A plasma treatment that can directly irradiate all vacuum ultraviolet light generated by plasma can irradiate light having a shorter wavelength with higher intensity, and is preferable.

(Plasma treatment)
The plasma treatment which is a preferable example of the light irradiation method having a wavelength of 150 nm or less used in the present invention will be described below.
As described above, the plasma treatment is preferably performed in an atmosphere substantially free of oxygen or water vapor. Examples of the method carried out in an atmosphere substantially free of oxygen or water vapor include a method of reducing the pressure in the apparatus or a gas flow method, but it is preferable to reduce the pressure. After reducing the pressure in the apparatus from atmospheric pressure (101325 Pa) to a pressure of 100 Pa or less, preferably 10 Pa or less using a vacuum pump, a predetermined gas is introduced and a predetermined pressure is applied to thereby create an atmosphere excited by plasma. to make.

The oxygen concentration and water vapor concentration under reduced pressure are generally evaluated by the oxygen partial pressure and the water vapor partial pressure. Specifically, the oxygen partial pressure is 10 Pa or less (oxygen concentration 0.001% (10 ppm)) or less, preferably the oxygen partial pressure is 2 Pa or less (oxygen concentration 0.0002% (2 ppm)) or less, the water vapor concentration is 10 ppm or less, preferably Is performed by introducing the gas described below after reducing the pressure to 1 ppm or less.
The atmospheric gas excited by the plasma emits energy and deactivates. At that time, depending on the type and pressure of the gas, vacuum ultraviolet light having various wavelengths is emitted. Plasma treatment can be roughly divided into two methods: low-pressure plasma treatment and plasma treatment near atmospheric pressure.

  In the step (a), a method using plasma may be used as a dry film forming method. However, in the step (a), the step (b) of irradiating light with a wavelength of 150 nm or less substantially doubles. Can not. The reason is that there is a gas as a material for the deposited film in the space where the plasma is formed and the space between the plasma and the dry deposited film 14 and the vacuum ultraviolet light generated from the plasma absorbs the vacuum wavelength of 150 nm or less. This is because the condition for efficiently performing light irradiation deviates.

[1] Low-pressure plasma treatment The low-pressure plasma treatment is performed by introducing the following gas species into the apparatus after reducing the pressure to make the atmosphere substantially free of oxygen or water vapor. In the low-pressure plasma treatment, vacuum ultraviolet emission is used when atoms and molecules excited by low-pressure plasma fall to the ground state or the lower level. The wavelength of the vacuum ultraviolet light generated by the low-pressure plasma depends on the gas species that generates the plasma. A shorter wavelength is better, and it is more preferable to use vacuum ultraviolet light having a wavelength of 125 nm or less. However, if the wavelength is too short, the frequency of excitation to a high energy level is low, and the emission intensity is significantly reduced. The wavelength of relatively high-intensity vacuum ultraviolet light that can be used substantially in the low-pressure plasma treatment is 50 nm or more. That is, the range of 50 to 125 nm is more preferable as the wavelength of light used in the low-pressure plasma treatment.
Preferred conditions for the low-pressure plasma treatment are as shown in the following (1) to (5).

(1) Vacuum ultraviolet light emitted by excited state atoms formed by pressure range plasma is absorbed by another ground state atom, which has the effect of self-absorption used to excite the atom. For this reason, the vacuum ultraviolet light generated when the pressure is too high is absorbed by the atoms and molecules of the atmospheric gas, and the dry deposition film 14 is not efficiently irradiated. Generally, a low pressure of 100 Pa or less is preferable. On the other hand, if the pressure is too low, generation of plasma becomes difficult. The lower limit of the pressure varies depending on the plasma generation method, but is generally preferably about 0.1 Pa or more.

(2) Gas species As the gas species of low-pressure plasma emitting vacuum ultraviolet light having a wavelength of 150 nm or less used in the present invention, one or more rare gases selected from He, Ne, and Ar are mainly used. The major vacuum ultraviolet light wavelengths emitted by these excited rare gas atoms are 58.4 nm for He, 73.6 nm and 74.4 nm for Ne, and 104.8 nm and 106.7 nm for Ar. It is known that

Further, the plasma of these rare gas atoms not only emits vacuum ultraviolet light when excited by plasma, but also forms a large amount of metastable excited atoms that do not emit light. In order to effectively use the energy of the metastable excited atoms, one or more gases selected from H 2 and N 2 may be added to the rare gas. When the gas is added at a specific ratio in the rare gas, the excitation energy of the rare gas atoms in the metastable excited state is efficiently used to excite the additive gas. In addition, vacuum ultraviolet emission of the additive gas is also added, and the irradiation intensity of vacuum ultraviolet light having a wavelength of 150 nm or less can be increased. The additive gas has a case where the dissociated / excited atom emits vacuum ultraviolet light and an excited molecule emits vacuum ultraviolet light, but the emission of the molecule is in a band shape, and its central wavelength is atomic. Longer than the emission wavelength. For the modification of the dry deposition film 14, emission of atoms having a short wavelength is more important. It is known that the wavelength of the main vacuum ultraviolet light emitted by the excited H atoms is 121.5 nm, and that in the case of N atoms is 120 nm. As the additive gas species, H2 having no metastable excited state is more preferable.

Preferred gas species are He, Ne, a mixed gas of He and H2, a mixed gas of Ne and H2, and a mixed gas of Ar and H2. The ratio of the additive gas is in the range of 0.1 to 20%. If it is less than 0.1%, the effect of the additive gas does not appear remarkably, and if it is 20% or more, the plasma density decreases remarkably due to the effect of the additive gas, and the rare state of the metastable excited state used for excitation of the additive gas appears. This is because the density of gas atoms is also reduced. Preferably it is 0.5 to 10% of range.
Further, in order to efficiently irradiate the dry deposited film 14 with vacuum ultraviolet light having a wavelength of 150 nm or less, gas species of polyatomic molecules that absorb light having a wavelength of 150 nm or less and decompose themselves (for example, CO, CO 2, It is more preferable that CH4Si-H4 or the like is not substantially contained.

(3) Power frequency The frequency of the power source required for generating low-pressure plasma that emits vacuum ultraviolet light having a wavelength of 150 nm or less used in the present invention is preferably 1 MHz to 100 GHz. When the frequency is less than 1 MHz, it is possible to follow the change in the electric field not only to the electrons in the plasma but also to the ions, so that it is impossible to efficiently give energy to the electrons that directly contribute to the plasma generation reaction. On the other hand, at a frequency of 1 MHz or higher, ions cannot follow changes in the electric field, so that energy can be efficiently given to electrons, and the electron density, that is, the plasma density is increased. Along with this, the intensity of the vacuum ultraviolet light generated by the plasma also increases. However, when the frequency exceeds 100 GHz, it becomes difficult for electrons to follow the change in the electric field, and the energy transfer efficiency deteriorates. Preferably, it is the range of 4 MHz-10 GHz.

(4) Plasma Generation Method As a method for generating plasma that emits vacuum ultraviolet light having a wavelength of 150 nm or less used in the present invention, a conventionally known method can be used. Preferably, a method that can deal with the treatment of the dry deposition film 14 formed on the wide substrate 12 is good, and examples thereof include the following methods (A) to (E).

(A) Capacitively coupled plasma (CCP)
A system that generates plasma between the electrode to which high-frequency power is applied and the electrode on the ground side. The opposed plate electrodes are a typical electrode structure. The electrode on the side to which the high-frequency power is applied is not limited to a flat plate shape, and may have an uneven shape as disclosed in Patent Document 5, for example. By providing a concavo-convex shape on the plate electrode, the plasma density can be increased due to the electric field concentration at the protrusion and the effect of the hollow cathode, and the intensity of VUV of 150 nm or less generated by the plasma is also increased.

(B) Inductively coupled plasma (ICP)
A high frequency current is passed through the antenna coil, and plasma is generated by an induced electric field generated by a magnetic field generated by the coil. Generally, a higher electron density (plasma density) is obtained than capacitively coupled plasma. Either an external antenna type in which the antenna coil is placed outside the chamber through a dielectric window or an internal antenna type in which the antenna coil is installed in the chamber may be adopted. Moreover, in order to correspond to a wide base material, you may devise, such as arrange | positioning an antenna coil in an array form.

In the apparatus configuration as described above, when the input power is increased, a discharge due to electrostatic coupling with the coil antenna (referred to as E mode) shifts to a discharge due to inductive coupling (referred to as H mode). In some cases, the current state where the plasma density rapidly increases as a mode jump phenomenon may be observed. When the dry deposition film 14 is processed, it is necessary to supply sufficient electric power so as to obtain H-mode plasma.
(C) Surface wave plasma (D) Electron cyclotron resonance (ECR) plasma (E) Helicon wave plasma

(5) Input power density As an index of the magnitude of the input power to the plasma facing the dry deposition film 14, the input power density normalized by the area occupied by the plasma source reflecting the plasma size is defined. This is a parameter that correlates with the irradiation intensity of the vacuum ultraviolet light applied to the dry deposition film 14 per unit area. In particular, in the case of electroded plasma such as capacitively coupled plasma, the area of the electrode on the side where the high frequency is applied substantially defines the size of the plasma, and this is the area occupied by the plasma source.

  The input power density is preferably 0.1 to 20 W / cm 2. More preferably, it is 0.3 to 10 W / cm 2 or more. When the input power density is 0.1 W / cm 2 or less, sufficient intensity of VUV irradiation cannot be performed. There is an adverse effect such as damage to the constituent members.

[2] Plasma processing near atmospheric pressure In plasma processing near atmospheric pressure, an atmosphere substantially free of oxygen or water vapor is created by reducing the pressure or gas flow, and then a predetermined gas species is introduced to evacuate the interior of the apparatus to a predetermined atmospheric pressure. Processing is performed at a pressure close to atmospheric pressure. Since the pressure is high, the emission of vacuum ultraviolet rays when atoms or molecules excited by plasma fall to the ground state or the lower level has a very large influence of self-absorption, and is effective for the modification of the dry deposited film 14. It cannot be used. Excimer emission is used in plasma processing near atmospheric pressure. As a practically usable excimer emission, Ar excimer emission formed by plasma using Ar gas has the shortest wavelength and has a central wavelength of 126 nm. From the viewpoint that vacuum ultraviolet light having a shorter wavelength can be used, the low-pressure plasma treatment is preferable as the plasma treatment method.
Preferred conditions for the plasma treatment near atmospheric pressure are as shown in the following (1) to (5).

(1) Gas species Among gas species that can be practically used in a plasma process near atmospheric pressure, it is Ar gas that can emit excimer light of 150 nm or less. Ar excimer (Ar ₂ ^* ) is supposed to be generated in a three-body collision reaction represented by the following formula based on metastable Ar atoms (Ar ^* ) formed by plasma.
Ar ^* + Ar + Ar → Ar ₂ ^* + Ar

  Therefore, the ratio of impurity gases other than Ar is preferably as small as not affecting the plasma density and the above reaction. The impurity concentration is preferably 1% or less, more preferably 0.5% or less. Furthermore, in order to efficiently irradiate the dry deposition film 14 with vacuum ultraviolet light having a wavelength of 150 nm or less, gas species of polyatomic molecules that absorb light in the vicinity of a wavelength of 126 nm and decompose themselves (for example, CO, CO 2, More preferably, CH4 etc. are not substantially contained.

(2) Pressure range The vicinity of atmospheric pressure refers to a pressure of 1 to 110 kPa, which can be used by opening it to the atmosphere, or when used in a sealed container and reducing the pressure slightly compared to atmospheric pressure, or slightly This means that it can also be used in a pressurized state. Slightly reducing the pressure makes it easier to discharge, so formation of metastable Ar atoms by plasma becomes easier. However, if the pressure is reduced too much, the Ar density decreases and an Ar excimer (Ar ₂ ^* ) formation reaction occurs. The frequency of occurrence of the three-body collision reaction is reduced. In order to increase the intensity of VUV emission by Ar excimer, it is more preferable to use a hermetically sealed container and a simple decompression device and set the pressure in the range of 10 to 90 kPa. In addition, if the pressure is reduced in such a range, the amount of gas used for the treatment can be reduced, and the amount of inhibitory components such as oxygen and water can be reduced.

(3) Plasma Forming Method As a method for generating plasma that emits an Ar excimer used in the present invention, a conventionally known method that can generate plasma near atmospheric pressure can be used. Preferably, the dry deposition film 14 can be directly irradiated with vacuum ultraviolet light emission of Ar ^* formed by plasma and Ar excimer (Ar ₂ ^* ) generated from Ar, and further, a wide base material. A method that can cope with the processing of the dry deposition film 14 formed on the substrate 12 is preferable. For example, a dielectric that forms a discharge plasma by disposing a substrate 12 with a dry deposition film 14 between electrodes having a dielectric disposed on at least one electrode surface, passing gas therethrough, and applying AC power between the electrodes. A direct processing method using barrier discharge can be used.

(4) Power frequency The power frequency is preferably in the range of 50 Hz to 1 GHz. Since the operating pressure range is different from the low-pressure plasma treatment, the power frequency band to be used is also different. Below 50 Hz, there are few metastable Ar atoms formed in the plasma, and high irradiation altitude excimer light cannot be obtained. Moreover, since the plasma gas temperature becomes high at 1 GHz or higher, the substrate 12 is thermally damaged. Preferably, it is in the range of 1 kHz to 100 MHz.

(Discharge power density)
As in the case of the low-pressure plasma treatment, the input power density normalized by the area occupied by the plasma source that reflects the plasma size is defined as an index of the power input to the plasma facing the dry deposition film 14. To do.
The input power density is preferably 0.1 to 20 W / cm 2. More preferably, it is 0.3 to 10 W / cm 2 or more. When the input power density is 0.1 W / cm 2 or less, VUV irradiation with sufficient intensity cannot be performed. When the input power density is 20 W / cm 2 or more, thermal deformation due to the temperature treatment of the substrate 12, plasma nonuniformity, plasma sources such as electrodes, etc. There is an adverse effect such as damage to the constituent members.

(Substrate heating)
In the step (b), the substrate 12 on which the dry deposition film 14 is placed can be processed in a shorter time simultaneously with the light irradiation with the wavelength of 150 nm or less. The higher the heat treatment temperature, the better, but considering the heat resistance of the substrate, it is preferably 25 ° C to 1000 ° C, more preferably 30 ° C to 500 ° C, and even more preferably 60 ° C to 300 ° C. is there.

DESCRIPTION OF SYMBOLS 10 Energy beam irradiation 12 Base material 14 Dry deposition film 16 Silicon-containing film 18 Denatured area 20 Slightly denatured area

Claims (8)

  A method for producing a silicon-containing film, comprising a step of depositing a dry deposition film containing at least silicon atoms and nitrogen atoms on a substrate by a dry method and then irradiating the film surface with light having a wavelength of 150 nm or less. .   2. The method for producing a silicon-containing film according to claim 1, wherein the dry deposition film is a film containing hydrogen derived from at least a Si-H bond or an N-H bond. 3. The silicon-containing film according to claim 1, wherein the dry method is a method selected from a vapor deposition method, a reactive vapor deposition method, a sputtering method, a reactive sputtering method, and a chemical vapor deposition method. Production method. The method for producing a silicon-containing film according to claim 1, wherein the dry method is a catalytic chemical vapor deposition method or a plasma chemical vapor deposition method. The method for producing a silicon-containing film according to claim 1, wherein the light irradiation with the wavelength of 150 nm or less is performed by plasma treatment.   The plasma treatment includes helium, neon, argon, a mixed gas of helium and hydrogen, a mixed gas of neon and hydrogen, a mixed gas of argon and hydrogen, a mixed gas of helium and nitrogen, a mixed gas of neon and nitrogen, and a mixture of argon and nitrogen. The method for producing a silicon-containing film according to claim 5, which is performed in a pressure atmosphere of 0.1 Pa or more and 100 Pa or less in the presence of an atmosphere gas selected from a mixed gas.   The method for producing a silicon-containing film according to claim 1, wherein the substrate is heated to 25 ° C. to 1000 ° C. simultaneously with the light irradiation with the wavelength of 150 nm or less. A laminate in which a silicon-containing film is formed on a substrate by the method according to claim 1.