JP4980598B2 - Crystal thin film manufacturing equipment - Google Patents

Description

  The present invention relates to an apparatus for producing a quartz thin film under atmospheric pressure.

  Quartz crystal thin films are used for oscillators, vibrators, surface acoustic wave elements for high-frequency filters, and the like. As a method for producing a quartz crystal thin film, a method of polishing a quartz single crystal obtained by a hydrothermal synthesis method to make a thin film is conventionally known. Further, as a method for directly producing a quartz crystal thin film, a sol-gel method, a plasma chemical vapor deposition (CVD) method, a sputtering method, a laser ablation method and the like are known. However, these production methods have problems such as low yield of crystal crystal thin films that are practically satisfactory, or the necessity of managing large-scale equipment and strict production conditions. It is not necessarily advantageous as a manufacturing method.

  Patent Document 1 describes an atmospheric pressure vapor phase epitaxial growth method as a method for producing a quartz crystal thin film that can be advantageously used industrially. In the atmospheric pressure vapor phase epitaxial growth method, the silicon alkoxide and oxygen introduced into the reaction vessel are reacted in the presence of a reaction accelerator such as hydrogen chloride at atmospheric pressure without using a vacuum apparatus, In this method, a quartz crystal thin film is epitaxially grown on a substrate. This document further describes that the crystallinity of the quartz crystal thin film formed thereon is improved by providing a buffer layer (eg, a quartz thin film or a gallium nitride thin film) on the substrate in advance.

In Non-Patent Document 1, a quartz crystal thin film preferentially oriented on the AT cut surface has an excellent advantage that the temperature dependence of the vibration frequency is low when it is used as a vibrator. A method of manufacturing a simple quartz crystal thin film by atmospheric pressure vapor phase epitaxy is disclosed. Specifically, it is said that when a two-layer crystal thin film is provided as a buffer layer on a substrate in advance, the crystal crystal thin film formed thereon can be preferentially oriented to the AT cut surface.
JP 2002-80296 A Naoyuki Takahashi and five others, “Rapid Growth of Thick Quartz Films by Catalyst-Enhanced Vapor-Phase Epitaxy under Atmospheric Pressure”, Electrochemical and Solid-State Letters, 6 (5) C77-C78 (2003)

  A quartz crystal thin film having excellent crystallinity can be formed on the substrate by the above atmospheric pressure vapor phase epitaxial growth method. The quartz crystal thin film thus formed on the substrate is, for example, peeled from the substrate and divided into a plurality of pieces, and each is used as a vibrator. For this reason, it is preferable to form a quartz crystal thin film on the substrate with as uniform a thickness as possible.

  An object of the present invention is to provide a quartz crystal thin film manufacturing apparatus that can be advantageously used to manufacture a quartz crystal thin film, particularly a quartz crystal thin film preferentially oriented to an AT cut surface, with a uniform thickness.

The present invention relates to a reaction vessel provided with an exhaust port, a substrate holder mounted in the reaction vessel, a surface of a substrate supported by the substrate holder that supplies an oxygen-containing gas into the reaction vessel, or a plane including the substrate surface. An oxygen-containing gas supply pipe arranged with a tip opening directed toward a region around the substrate of the substrate, a silicon alkoxide-containing gas supply port for supplying a gas containing silicon alkoxide into the reaction vessel, and a reaction A reaction accelerator supply port for supplying a gas containing a reaction accelerator in the container, and each of the silicon alkoxide-containing gas supply port and the reaction accelerator supply port has the same end in the reaction container with respect to the mounting position of the substrate holder. An apparatus for producing a quartz thin film under atmospheric pressure that is open on the part side,
The reaction vessel is a cylindrical reaction vessel arranged horizontally, and
The cylindrical reaction vessel includes a silicon alkoxide-containing gas in which the openings between the silicon alkoxide-containing gas supply port and the reaction accelerator supply port and the mounting position of the substrate holder are partitioned by a wall having an opening. In the quartz thin film manufacturing apparatus, a mixing chamber is formed for mixing the reaction accelerator and the reaction accelerator prior to contact with the oxygen-containing gas .

The preferable aspect of the crystal thin film manufacturing apparatus of the present invention is as follows.
(1) The reaction vessel is a cylinder, and a heating tool is disposed outside the cylinder.
(2) The heating tool is divided into a plurality of heating units along the longitudinal direction of the cylinder, and the heating conditions of each heating unit are controlled independently of each other.
(3) Openings in the mixing chamber, tip openings in the gas supply pipe for oxygen-containing gas, and substrate holders are arranged inside the reaction vessel with a space between each other, and each has a through-hole through which gas flows. A pair of provided partition walls is provided.
(4) The front end opening of the gas supply pipe for the oxygen-containing gas is provided at a position closer to the substrate holder than the opening of the mixing chamber.
(5) A cylindrical shield having an inner surface made of a material inert to silicon oxide in a gas phase is detachably mounted in the reaction vessel, and the above-mentioned inside the cylindrical shield is A substrate holder is provided.
(6) The material inert to the silicon oxide in the gas phase is aluminum oxide, silicon carbide, or trisilicon tetranitride.
(7) The front end opening of the gas supply pipe for the oxygen-containing gas is disposed inside the cylindrical shield.
(8) A gas supply pipe of oxygen-containing gas includes a gas supply pipe main body and a tip opening unit that is detachably attached to the tip of the gas supply pipe main body.
(9) The supply port for the silicon alkoxide-containing gas is formed as a gas supply pipe whose tip reaches the inside of the mixing chamber.
(10) The gas supply pipe for the silicon alkoxide-containing gas includes a gas supply pipe main body and a tip opening unit that is detachably attached to the tip of the gas supply pipe main body.
(11) The reaction accelerator is hydrogen chloride or ammonia.
(12) The reaction vessel has all the gas supply ports and gas supply pipes at one end, and has a cylindrical container having an opening at the other end and an exhaust port, and the opening of the cylindrical container It is the cylinder which consists of a cover part with which the attachment or detachment was carried out.
(13) The cylindrical container is disposed in the horizontal direction, and the substrate holder is disposed so as to support the substrate in an oblique direction with respect to the wall surface of the cylindrical container.

  In the quartz thin film manufacturing apparatus of the present invention, a gas containing silicon alkoxide and a gas containing a reaction accelerator (hydrogen chloride, ammonia, etc.) for promoting the growth of the quartz thin film are mixed in a mixing chamber provided in the reaction vessel. Since it is supplied to the substrate surface after being mixed in advance, the amount of the reaction accelerator added to the silicon alkoxide becomes uniform in the vicinity of the substrate surface. Therefore, by using the quartz thin film manufacturing apparatus of the present invention, the silicon alkoxide supplied to the substrate surface together with the reaction accelerator as described above and oxygen are brought into contact with each other in a uniform atmosphere to cause a reaction on the substrate. A quartz thin film having a highly uniform thickness can be formed.

  And the quartz crystal thin film manufacturing apparatus of the present invention is, for example, adjusting the supply amount of each of silicon alkoxide and oxygen, adjusting the contact position between silicon alkoxide and oxygen (that is, the production position of crystal by reaction of these raw material gases), Alternatively, the crystallinity of the obtained crystal thin film can be easily adjusted by adjusting the temperature in the reaction vessel with a heating tool arranged outside the reaction vessel. Thus, by adjusting the crystallinity of the quartz thin film, for example, when a buffer layer made of an amorphous quartz thin film is formed on the substrate in accordance with the description in Patent Document 1, the crystallinity is excellent on the buffer layer. A quartz crystal thin film can be formed with a uniform thickness, and two buffer layers each made of a quartz thin film (specifically, a quartz crystal used as an upper buffer layer) are formed on a substrate in accordance with the contents of Non-Patent Document 1. When the crystallinity of each buffer layer is adjusted so that the crystallinity of the thin film is higher than the crystallinity of the crystal thin film used as the lower buffer layer, the AT cut surface is formed on these buffer layers. Thus, it is possible to form a quartz crystal thin film with a uniform thickness.

  Thus, the crystal thin film manufacturing apparatus of the present invention can be advantageously used to manufacture a crystal crystal thin film, particularly a crystal crystal thin film preferentially oriented on the AT cut surface, with a uniform thickness.

  The crystal thin film manufacturing apparatus of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing a configuration example of a crystal thin film manufacturing apparatus according to the present invention and a method of supplying a raw material gas to the crystal thin film manufacturing apparatus 10. 2 is a cross-sectional view of the quartz crystal thin film manufacturing apparatus 10 shown in FIG.

  The crystal thin film manufacturing apparatus 10 shown in FIGS. 1 and 2 supplies a reaction vessel 12 having an exhaust port 11, a substrate holder 13 mounted in the reaction vessel 12, and an oxygen-containing gas into the reaction vessel 12. A gas supply pipe 22 arranged with a front end opening facing the surface of the substrate 14 supported by the substrate holder 13 with a space therebetween, and a supply port 71 for supplying a gas containing silicon alkoxide into the reaction vessel 12 A supply port 73 for supplying a gas containing a reaction accelerator into the reaction vessel 12 and between the end of the reaction vessel 12 on each gas supply port side and the installation position of the substrate 14. It comprises a mixing chamber 80 of a silicon alkoxide-containing gas and a reaction accelerator-containing gas having an opening 82a facing the surface.

  The gas supply pipe of the oxygen-containing gas has a tip opening portion (from the surface side of the substrate 14) directed to a region around the substrate 14 on a plane including the surface of the substrate 14 supported by the substrate holder 13 with a space therebetween. May be arranged. In this specification, the “region around the substrate on the plane including the substrate surface” refers to the diameter of the substrate from the edge of the substrate surface on the plane including the substrate surface (if the substrate is not circular, It means an area within a distance within a half of the diameter of a circle circumscribing the substrate.

  The mixing chamber 80 is configured by dividing the interior of the reaction vessel 12 by a wall body 81 and a wall body 82 having an opening 82a. In the case of the crystal thin film manufacturing apparatus 10 shown in FIGS. 1 and 2, the silicon alkoxide-containing gas supply port 71 is formed as a gas supply pipe 21 whose tip reaches the inside of the mixing chamber 80. That is, the silicon alkoxide-containing gas supplied from the supply port 71 into the reaction vessel is supplied into the mixing chamber 80 through the gas supply pipe 21. On the other hand, the gas containing the reaction accelerator supplied from the supply port 73 of the reaction vessel 12 passes through the through hole 91a of the partition wall 91 described later and the through hole 81a provided in the wall body 81 and enters the inside of the mixing chamber 80. Supplied.

  3 and 4 are views of the wall body 81 and the wall body 82 shown in FIG. 2 as viewed from the left side of the drawing. As shown in FIG. 3, the wall 81 includes a gas supply pipe 21 containing a silicon alkoxide-containing gas, a gas supply pipe 22 containing an oxygen-containing gas, a reaction accelerator-containing gas supplied from a supply port 73 into the reaction vessel, and A through-hole 81a is formed through which dilution gas supplied from the supply port 74 into the reaction vessel for adjusting the concentration of the gas in the reaction vessel passes. As shown in FIG. 4, the wall 82 includes an oxygen-containing gas supply pipe 22, and an opening through which the silicon alkoxide-containing gas, reaction accelerator-containing gas, and dilution gas mixed in the mixing chamber 80 pass. 82a is formed. Each of the wall bodies 81 and 82 is made of, for example, quartz glass.

  In the crystal thin film manufacturing apparatus 10, a gas containing silicon alkoxide (silicon alkoxide vapor) supplied from the supply port 71 into the reaction vessel and a gas containing a reaction accelerator supplied from the supply port 73 into the reaction vessel. Are mixed in advance in the mixing chamber 80 and then supplied to the substrate surface through the opening 82a, so that the addition amount of the reaction accelerator to the silicon alkoxide becomes uniform in the vicinity of the substrate surface. Therefore, by using the quartz crystal thin film manufacturing apparatus 10 of the present invention, the silicon alkoxide supplied to the substrate surface together with the reaction accelerator as described above is brought into contact with oxygen in a uniform atmosphere under atmospheric pressure to cause a reaction. As a result, a crystal thin film having a highly uniform thickness can be formed on the substrate. In this specification, atmospheric pressure means not only atmospheric pressure, but also pressure close to atmospheric pressure (within twice the atmospheric pressure and a pressure of 1/2 or more).

  As the silicon alkoxide, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, or a mixture of any combination thereof is used. The oxygen may be an oxygen supply source such as ozone, dinitrogen monoxide, or water.

  As the reaction accelerator, for example, hydrogen chloride is used. Hydrogen chloride cuts the bond between silicon and oxygen in the silicon alkoxide, and promotes the reaction (oxidation of silicon alkoxide) between the silicon alkoxide and the oxygen-containing gas supplied from the tip opening of the gas supply pipe 22. It is understood to increase the deposition rate of the quartz thin film. Examples of the reaction accelerator include an acidic gas typified by hydrogen chloride and a basic gas typified by ammonia.

  In the crystal thin film manufacturing apparatus 10, the silicon alkoxide and the reaction accelerator are mixed in the mixing chamber 80 provided in the reaction vessel 12 immediately before the silicon alkoxide and oxygen are brought into contact with each other to be reacted. This is presumed to be a decomposition product or oxide of silicon alkoxide in the gas supply pipe for supplying this mixed gas into the reaction vessel when silicon alkoxide and reaction accelerator are mixed in advance outside the reaction vessel 12. This is because the compound may adhere and the gas supply pipe may be clogged.

  Examples of the dilution gas supplied from the supply port 74 to the reaction vessel include nitrogen and an inert gas such as argon or helium.

  Each of the silicon alkoxide, oxygen, reaction accelerator, and diluent gas is supplied into the reaction vessel 12 as follows, for example.

  Silicon alkoxide, for example, tetraethoxysilane (denoted as “TEOS” in FIG. 1) is liquid at room temperature and is placed inside the vaporizer 19. The tetraethoxysilane put in the vaporizer 19 is heated and vaporized by operating the heater 36, and is supplied to the inside of the reaction vessel 12 through the supply port 71. As shown in FIG. 2, in the case of the quartz crystal thin film manufacturing apparatus 10, the supply port 71 of the silicon alkoxide-containing gas is formed as a gas supply pipe 21 whose tip reaches the inside of the mixing chamber 80. The silicon alkoxide-containing gas supplied inside is supplied into the mixing chamber 80 through the gas supply pipe 21. As the heater 36, for example, a high frequency induction heater or a resistance heater is used. In order to keep the tetraethoxysilane contained in the vaporizer 19 at a constant temperature (for example, 70 ° C.), the heater 36 is provided with a control device 46.

Tetraethoxysilane is usually supplied into the reaction vessel 12 together with nitrogen (N ₂ ) used as a carrier gas. This is because by using the carrier gas, tetraethoxysilane can be efficiently and accurately supplied into the reaction vessel 12. Examples of the carrier gas include inert gases such as argon and helium in addition to the above nitrogen.

  Nitrogen used as a carrier gas for tetraethoxysilane is supplied from the gas cylinder 51c to the vaporizer 19 through the manual valve 52c, the air operated valve 54c, and the mass flow controller 55c, and is supplied together with the tetraethoxysilane vaporized in the vaporizer. It is supplied into the reaction vessel 12 through the port 71. The flow rate of nitrogen supplied to the vaporizer 19 is controlled by the mass flow controller 55c. Further, the supply of nitrogen used as a carrier gas to the vaporizer 19 can be started or stopped by opening and closing the air operated valve 54c. The pressure sensor 53c is used for checking the remaining amount of nitrogen put in the gas cylinder 51c.

Oxygen (O ₂ ) is supplied from the gas cylinder 51 b to the inside of the reaction vessel 12 through the manual valve 52 b, the air operated valve 54 b, the mass flow controller 55 b, and the supply port 72. The supply port 72 is formed as a gas supply pipe 22 extending to the inside of the reaction vessel 12, and the front end opening of the gas supply pipe 22 is the surface of the substrate 14 supported by the substrate holder 13 (or the substrate 14). A region surrounding the substrate 14 on a plane including the surface). The flow rate of oxygen is controlled by the mass flow controller 55b. Further, the supply of oxygen to the reaction vessel 12 can be started or stopped by opening / closing the air operated valve 54b. The pressure sensor 53b is used to check the remaining amount of oxygen in the gas cylinder 51b.

  As in the case of supplying the above tetraethoxysilane, oxygen is usually supplied into the reaction vessel 12 together with nitrogen used as a carrier gas. Nitrogen used as a carrier gas for oxygen is mixed with oxygen after passing through a gas cylinder 51c, a manual valve 52c, an air-operated valve 54d, and a mass flow controller 55e. Supplied inside. The flow rate of nitrogen used as the oxygen carrier gas is controlled by the mass flow controller 55e. The supply of nitrogen used as an oxygen carrier gas can be started or stopped by opening / closing the air operated valve 54d.

  Hydrogen chloride (HCl) used as a reaction accelerator is, for example, a mixed valve in which hydrogen chloride is mixed with nitrogen used as a carrier gas at a ratio of 5% by volume from a gas cylinder 51a to a manual valve 52a, an air operated valve 54a, It is supplied into the reaction vessel 12 through the mass flow controller 55 a and the supply port 73. The mixed gas of hydrogen chloride and nitrogen supplied to the inside of the reaction vessel 12 is supplied to the inside of the mixing chamber 80 through a through hole 91a of the partition wall 91 and a through hole 81a of the wall body 81 which will be described later. The flow rate of the mixed gas of hydrogen chloride and nitrogen is controlled by the mass flow controller 55a. Further, the supply of the mixed gas of hydrogen chloride and nitrogen to the reaction vessel 12 can be started or stopped by opening and closing the air operated valve 54a. The pressure sensor 53a is used for confirming the remaining amount of the mixed gas put in the gas cylinder 51a.

  Nitrogen used as a diluent gas for adjusting the gas concentration inside the reaction vessel 12 is, for example, from the gas cylinder 51c through the manual valve 52c, the air operated valve 54d, the mass flow controller 55d, and the supply port 74. Supplied inside. The flow rate of nitrogen used as the dilution gas is controlled by the mass flow controller 55d. The supply of nitrogen used as a dilution gas to the reaction vessel 12 can be started or stopped by opening / closing the air operated valve 54d.

  Thus, the silicon alkoxide-containing gas and the reaction accelerator-containing gas supplied into the reaction vessel 12 become a highly uniform mixed gas inside the mixing chamber 80.

  As shown in FIG. 2, the gas supply pipe 21 that supplies the silicon alkoxide-containing gas into the mixing chamber 80 is detachably attached to the gas supply pipe main body 21 a and the gas supply pipe main body 21 a at the distal end. 21b. As shown in FIG. 2, the tip opening unit 21b is bent, and a clockwise flow occurs in the gas in the mixing chamber on the paper surface of FIG. 2, so that the silicon alkoxide-containing gas and the reaction accelerator-containing gas are uniform. Mixed. By exchanging the tip opening unit 21b with another one, the position of the tip opening or the direction of the tip opening of the gas supply pipe 21a is adjusted to react with the silicon alkoxide-containing gas inside the mixing chamber 80. The mixing state with the accelerator-containing gas can be adjusted.

  FIG. 5 is a diagram illustrating another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas in the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 5 is the same as that of the gas supply pipe 21 shown in FIG. 2 except that the diameter of the tip opening unit 21c is set larger as it goes toward the tip opening. Since the silicon alkoxide-containing gas can be diffused into the reaction accelerator-containing gas by using the tip opening unit 21c, the silicon alkoxide-containing gas and the reaction accelerator-containing gas are converted into the tip opening unit 21b shown in FIG. It can mix more uniformly than the case where it uses.

  FIG. 6 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 6 is the same as that of the gas supply pipe 21 shown in FIG. 5 except that the tip opening of the tip opening unit 21d is formed as a plurality of through holes. By using the tip opening unit 21d, the silicon alkoxide-containing gas can be brought into contact with the reaction accelerator-containing gas in the state of a thin airflow flowing out from the plurality of through holes. Therefore, the silicon alkoxide-containing gas, the reaction accelerator-containing gas, Can be uniformly mixed in a shorter time than when the tip opening unit 21c shown in FIG. 5 is used.

  FIG. 7 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 7 is the same as that of the gas supply pipe 21 shown in FIG. 5 except that the tip opening of the tip opening unit 21e is directed downward. Since the gas flow in the clockwise direction in the mixing chamber becomes smoother by using the tip opening unit 21e, the tip opening unit 21c shown in FIG. 5 is used for the silicon alkoxide-containing gas and the reaction accelerator-containing gas. It is possible to mix more uniformly than in the case.

  FIG. 8 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 8 is the same as that of the gas supply pipe 21 shown in FIG. 6 except that the tip opening of the tip opening unit 21f is directed downward. By using the tip opening unit 21f, the gas flow in the clockwise direction in the mixing chamber becomes smoother. Therefore, the tip opening unit 21d shown in FIG. 6 is used for the silicon alkoxide-containing gas and the reaction accelerator-containing gas. It is possible to mix more uniformly than in the case.

  FIG. 9 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas in the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 9 is the same as that of the gas supply pipe 21 shown in FIG. 7 except that the tip opening unit 21g is curved in a U shape. By using the tip opening unit 21g, the gas flow in the clockwise direction in the mixing chamber becomes smoother, so that the silicon alkoxide-containing gas and the reaction accelerator-containing gas are used as the tip opening unit 21e shown in FIG. It is possible to mix more uniformly than in the case.

  FIG. 10 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 10 is the same as that of the gas supply pipe 21 shown in FIG. 8 except that the tip opening unit 21h is curved in a U shape. By using the tip opening unit 21h, the gas flow in the clockwise direction in the mixing chamber becomes smoother. Therefore, when the tip opening unit 21f shown in FIG. 8 is used for the silicon alkoxide-containing gas and the reaction accelerator-containing gas. Can be mixed more uniformly.

  FIG. 11 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The gas supply pipe 21 shown in FIG. 11 includes a straight tubular tip opening unit 21i arranged coaxially with the gas supply pipe main body 21a. When a straight tubular tip opening unit is used, the length of the gas supply pipe main body 21a is set short as shown in FIG. 11, and the tip opening of the gas supply pipe 21 and the opening 82a of the mixing chamber 80 are separated. By increasing the interval, the silicon alkoxide-containing gas supplied from the tip opening of the gas supply pipe 21 to the inside of the mixing chamber can be diffused into the reaction accelerator-containing gas. The agent-containing gas can be mixed uniformly.

  FIG. 12 is a view for explaining still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas in the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 12 is such that the gas supply pipe main body 21a extends to a substantially central position between the wall body 81 and the wall body 82 of the mixing chamber, and a plurality of side walls of the tip opening unit 21j are provided. Except that a through hole is formed, it is the same as the gas supply pipe 21 shown in FIG. By using the tip opening unit 21j, the silicon alkoxide-containing gas can be brought into contact with the reaction accelerator-containing gas in the state of a thin airflow flowing out from the plurality of through holes. Therefore, the silicon alkoxide-containing gas, the reaction accelerator-containing gas, Can be uniformly mixed in a shorter time than when the tip opening unit 21i shown in FIG. 11 is used.

  FIG. 13 is a diagram illustrating still another configuration example of the gas supply pipe for supplying the silicon alkoxide-containing gas of the crystal thin film manufacturing apparatus of the present invention. The configuration of the gas supply pipe 21 shown in FIG. 13 is such that the gas supply pipe main body 21a extends to a substantially central position between the wall body 81 and the wall body 82 of the mixing chamber, and the tip opening unit 21k is curved in a U shape. Except for this, it is the same as the gas supply pipe 21 shown in FIG. Since the gas flow in the clockwise direction in the mixing chamber becomes smoother by using the tip opening unit 21k, the silicon alkoxide-containing gas and the reaction accelerator-containing gas are used compared to the case of using the tip opening unit 21i shown in FIG. Can be mixed uniformly.

  On the other hand, as shown in FIG. 2, the gas supply pipe 22 for the oxygen-containing gas is also composed of a gas supply pipe main body 22a and a tip opening unit 22b that is detachably attached to the tip of the gas supply pipe main body 22a. Preferably it is. With such a configuration, the position of the tip opening portion of the gas supply pipe 22 is changed by adjusting the attachment position of the tip opening unit 22b to the gas supply pipe main body 22a, or the tip opening unit 22b is exchanged for another shape. This makes it possible to make fine adjustments. Then, depending on the temperature distribution of the reaction container 12 when the reaction container 12 of the quartz crystal thin film manufacturing apparatus 10 is heated or the size of the substrate 14 supported by the substrate holder 13, the front end opening of the gas supply pipe 22 for the oxygen-containing gas is used. By finely adjusting the position of the portion, that is, the position where the silicon alkoxide and oxygen react, the crystallinity or thickness uniformity of the crystal thin film formed on the substrate 14 can be finely adjusted.

  Further, the front end opening unit 22b of the gas supply pipe 22 for oxygen-containing gas supplies oxygen supplied from the gas supply pipe 22 and silicon alkoxide supplied from the opening 82a of the mixing chamber 80 to the surface of the substrate 14 or its It is preferable to bend in order to bring them into contact with each other at nearby positions.

The distal end opening of the oxygen-containing gas supply pipe 22b is preferably provided at a position closer to the substrate holder 13 than the opening 82a of the mixing chamber 80 as shown in FIG. That is, the distance (L ₂ ) between the opening of the gas supply pipe 22 for oxygen-containing gas and the substrate 14 is set to be shorter than the distance (L ₁ ) between the opening 82 a of the mixing chamber 80 and the substrate. Is preferred. When the gas supply pipe 22 for the oxygen-containing gas is arranged in this way, the mixed gas of the silicon alkoxide-containing gas and the reaction accelerator-containing gas flowing out from the opening 82 a of the mixing chamber 80 is sufficiently uniformly diffused inside the reaction vessel 12. Then, it can be reacted with oxygen supplied from the gas supply pipe 22 of the oxygen-containing gas, so that a quartz thin film having a more uniform thickness can be formed on the substrate 14.

  As shown in FIGS. 1 and 2, the reaction vessel 12 of the crystal thin film manufacturing apparatus 10 is a cylindrical body, and it is preferable that a heating tool 30 is disposed outside the cylindrical body. By heating the reaction vessel 12 using the heating tool 30, the crystallinity of the crystal thin film formed on the substrate 14 can be adjusted.

  The heating tool disposed outside the cylinder (reaction vessel) is divided into a plurality of heating units along the longitudinal direction of the cylinder, and the heating conditions of each heating unit can be controlled independently of each other. preferable. The heating tool 30 of the crystal thin film manufacturing apparatus 10 shown in FIGS. 1 and 2 is divided into three heating units 31, 32, and 33 along the length direction of the cylinder, and each heating condition is controlled independently. Control devices 41, 42, and 43 are provided. As each of the three heating units 31, 32, and 33, for example, a high-frequency induction heater or a resistance heater having an annular shape along the circumferential direction of the reaction vessel 12 is used.

  In this way, by controlling the heating conditions of each of the heating units 31, 32, and 33 of the reaction vessel independently and adjusting the temperature distribution in the reaction vessel, the crystallinity of the crystal thin film formed on the substrate is reduced. Can be adjusted.

  Further, the temperature of the end of the reaction vessel 12 on the gas supply port side or the exhaust port side is likely to be lower than that of the central portion. For this reason, the low-temperature gas cooled at each end of the reaction vessel 12 circulates from the lower end of the reaction vessel to the lower center, the upper center, and the upper end of the reaction vessel to easily generate convection. Thus, when convection occurs inside the reaction vessel 12, the mixing ratio of silicon alkoxide and oxygen or the temperature of the substrate fluctuates, making it difficult to obtain a quartz thin film with stable quality.

  In order to suppress the occurrence of such convection in the reaction vessel, the quartz crystal thin film manufacturing apparatus of the present invention includes the opening 82a of the mixing chamber 80, the tip opening of the gas supply pipe 22 for the oxygen-containing gas, and the substrate holder 14. It is preferable that a pair of partition walls 91, 92 each having a through hole 91 a, 92 a, which is disposed inside the reaction vessel 12 with a space therebetween and through which gas flows, are preferably provided. For example, the partition wall 92 inhibits the flow of gas from the lower end of the reaction vessel to the lower center of the reaction vessel and the flow of gas from the upper upper portion to the upper end of the reaction vessel, thereby suppressing the occurrence of convection in the reaction vessel. . By providing such partition walls 91 and 92, fluctuations in the mixing ratio of silicon alkoxide and oxygen or the substrate temperature can be suppressed, and a quartz thin film can be manufactured with stable quality.

  As shown in FIG. 2, a partition wall 93 may be further arranged inside the reaction vessel 12. If the number of partition walls arranged in the reaction vessel is too large, it takes time to assemble the crystal thin film manufacturing apparatus. Therefore, the number of partition walls to be added is preferably 1 to 4.

  14 and 15 are views of the partition wall 91 and the partition wall 92 shown in FIG. 2 as viewed from the left side of the drawing. As shown in FIG. 14, the partition wall 91 includes a gas supply pipe 21 for a silicon alkoxide-containing gas, a gas supply pipe 22 for an oxygen-containing gas, and a reaction accelerator supplied from the supply port 73 of the reaction vessel 12 into the reaction vessel. A through hole 91a is formed through which the gas and the dilution gas supplied from the supply port 74 into the reaction vessel pass. As shown in FIG. 15, the partition wall 92 is formed with a through hole 92 a through which the silicon alkoxide-containing gas, oxygen-containing gas, reaction accelerator-containing gas, and diluent gas remaining after the formation of the crystal thin film are passed. Similarly, a through-hole 93a is formed in the partition wall 93 shown in FIG. Each of the partition walls 91, 92, and 93 is made of, for example, quartz glass.

  Further, as shown in FIG. 2, the reaction vessel is a cylinder having all gas supply ports 71, 72, 73, 74 and gas supply pipes 21, 22 at one end and an opening at the other end. The cylindrical body is preferably formed of a cylindrical container 12a and a lid 12b having an exhaust port 11 and detachably attached to the opening of the cylindrical container 12a. Moreover, it is preferable that the cylindrical container 12a is arrange | positioned in the horizontal direction, and the board | substrate holder 13 is arrange | positioned so that the board | substrate 14 may be supported in the diagonal direction with respect to the wall surface of the cylindrical container 12a. With such a configuration, the gas flow inside the reaction vessel 12 becomes smooth (it becomes difficult to generate convection), and the quality (eg, crystallinity and thickness uniformity) of the obtained quartz thin film is stabilized. Further, in order to prevent gas leakage to the outside of the reaction vessel 12, the lid portion 12b is attached to the opening of the cylindrical vessel 12a via, for example, an O-ring 18.

  The reaction vessel 12 can visually confirm the support position of the substrate 14 with respect to the substrate holder 13 or the relative positional relationship between the substrate 14 and the gas supply pipe 21 of the silicon alkoxide-containing gas or the gas supply pipe 22 of the oxygen-containing gas. In order to achieve this, for example, a transparent material made of quartz glass or the like is preferable. The substrate holder 13 is attached to a substrate holder fixture 17 made of, for example, quartz glass. The substrate holder fixture 17 is set in a curved shape along the inner surface of the reaction vessel 12.

  Further, inside the reaction vessel 12, a cylindrical shield 15 whose inner surface is made of a material inert to silicon oxide in a gas phase state is detachably attached, and the cylindrical shield 15 It is preferable that the substrate holder 13 is provided inside. Aluminum oxide, silicon carbide, or trisilicon tetranitride is preferably used as the material inert to the silicon oxide in the gas phase.

  As described above, when a raw material silicon alkoxide is reacted with oxygen to produce a crystal thin film on the substrate 14, the crystal easily adheres to the inner surface of the reaction vessel 12 in the form of a thin film. In particular, when the reaction vessel is made of quartz glass, the quartz thin film tends to adhere to the inner surface of the reaction vessel. When the crystal thin film adheres to the inner surface of the reaction vessel, the amount of the crystal thin film obtained on the substrate is smaller than the supply amount of the silicon alkoxide and oxygen as raw materials. That is, it becomes difficult to produce a quartz thin film on a substrate with a certain degree of efficiency.

  Also, if the reaction vessel is made of quartz glass and the quartz thin film adheres to the inner surface of the reaction vessel, as the production of the quartz thin film on the substrate is repeated, the glassy quartz that is the material of the reaction vessel and the reaction vessel inside Crystals deposited on the surface react with each other, causing crystals to precipitate in the quartz glass, resulting in a decrease in transparency (called devitrification), and the mechanical strength of the reaction vessel gradually decreases. Eventually, the reaction vessel cracks. Since the quartz thin film is firmly attached to the inner surface of the reaction vessel and it is difficult to remove it, it is necessary to frequently exchange the reaction vessel by managing its use time.

  As described above, a cylindrical shield 15 made of, for example, aluminum oxide, silicon carbide, or trisilicon tetranitride, which is a material inactive with respect to a silicon oxide in a vapor state, is placed inside the reaction vessel 12. When placed, the quartz thin film is prevented from adhering to the inner surface of the reaction vessel, and it is difficult for the quartz film to adhere to the inner surface of the cylindrical shield. it can. Further, when the reaction vessel is formed from quartz glass, the exchange frequency can be lowered.

  When the crystal thin film manufacturing apparatus 10 includes the cylindrical shield 15, it is preferable that the distal end opening of the gas supply pipe 22 for the oxygen-containing gas is disposed inside the cylindrical shield 15. Thereby, even if the supply amount of the source gas is the same, a larger amount of crystal is deposited on the surface of the substrate 14 so that the crystal thin film can be formed on the substrate efficiently (that is, at a high film formation rate). Become. Further, the amount of crystal attached to the inner surface of the reaction vessel 12 made of quartz glass (or a cylindrical support 103 formed of quartz glass, which will be described later) is further reduced, and the reaction vessel (or support 103) is further reduced. ) Can be further reduced.

  The crystal thin film manufacturing apparatus 10 shown in FIGS. 1 and 2 can be assembled, for example, according to the following procedure. First, a reaction vessel 12 including a cylindrical vessel 12a including a gas supply pipe 21 for a silicon alkoxide-containing gas and a gas supply pipe 22 for an oxygen-containing gas and a lid portion 12b is prepared. Next, the partition wall 91 and the cylindrical support tool 102 are inserted from the opening of the cylindrical container 12a, and the partition wall 91 is supported by the support tool 101 fixed in the cylindrical container and the cylindrical support tool 102. And placed inside the reaction vessel 12. The support tool 101 is set in a curved shape along the inner surface of the reaction vessel 12. Similarly, inside the cylindrical container 12a, a wall 81, a cylindrical support 103, a wall 82, a cylindrical shield 15 in which the substrate holder 13 is arranged inside, a partition wall 93, and a cylindrical support 104. The partition 92 and the cylindrical support 105 are inserted in this order. Then, the crystal thin film manufacturing apparatus 10 can be assembled by attaching the lid 12b to the opening of the cylindrical container 12a via the O-ring 18 and temporarily fixing them with an appropriate jig (not shown). it can.

  Each of the above supports 101, 102, 103, 104, 105 is made of, for example, quartz glass. Each support may be formed of a material that has an inner surface that is inactive with respect to silicon oxide in a gas phase, as in the case of the cylindrical shield 15.

  Further, the reaction gas enters the reaction container 12 into the gap between the cylindrical container 12a and the lid portion 12b, and crystal is formed on the end surface of the cylindrical container on the lid portion side and the end surface of the lid portion on the cylindrical container side. Is preferably provided with an annular shield 16. The annular shield 16 is made of, for example, a fluororesin.

For example, when a buffer layer made of an amorphous crystal thin film is formed on a substrate according to the description in Patent Document 1 using the crystal thin film manufacturing apparatus of the present invention, a crystal crystal having excellent crystallinity is formed on the buffer layer. A thin film can be formed to a uniform thickness, and in accordance with the contents of Non-Patent Document 1, two buffer layers (specifically, crystals of a crystal thin film used as an upper buffer layer) are formed on the substrate. The crystallinity of each buffer layer is adjusted so that it is higher than the crystallinity of the crystal thin film used as the lower buffer layer), the AT cut surface is given priority over these buffer layers. It is possible to form a quartz crystal thin film oriented in a uniform thickness.

  As the buffer layer, for example, the same silicon alkoxide and oxygen at a substrate temperature lower (for example, 20 to 200 ° C.) lower than the substrate temperature at the time of forming the quartz crystal thin film by the reaction of silicon alkoxide and oxygen. Can be used. When forming the two buffer layers, the substrate temperature is lower (for example, 10 to 100 ° C. lower) than the substrate temperature when the lower buffer layer is formed (for example, in the range of 40 to 530 ° C.). It is preferable to form the upper buffer layer at the substrate temperature), and it is more preferable to adjust the crystallinity by annealing after the formation of each buffer layer. The substrate temperature when forming the quartz crystal thin film on these buffer layers is particularly preferably in the range of 550 to 600 ° C.

  Further, as the substrate on which the quartz crystal thin film is formed, an Si substrate, a GaAs substrate, or a sapphire substrate is preferably used, and a sapphire substrate having a (110) A plane is particularly preferable.

  As described above, the quartz crystal thin film manufacturing apparatus of the present invention can be advantageously used for producing a quartz crystal thin film, particularly a quartz crystal thin film preferentially oriented on the AT cut surface, with a uniform thickness.

It is a figure which shows the structural example of the quartz thin film manufacturing apparatus of this invention, and the supply method of the raw material gas to this quartz thin film manufacturing apparatus. It is sectional drawing of the crystal thin film manufacturing apparatus 10 shown in FIG. It is the figure which looked at the wall 81 shown in FIG. 2 from the left side of the figure. It is the figure which looked at the wall 82 shown in FIG. 2 from the left side of the figure. It is a figure explaining another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is a figure explaining the further another structural example of the gas supply pipe | tube which supplies the silicon alkoxide containing gas of the crystal thin film manufacturing apparatus of this invention. It is the figure which looked at the partition 91 shown in FIG. 2 from the left side of the figure. It is the figure which looked at the partition 92 shown in FIG. 2 from the left side of the figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Quartz thin film manufacturing apparatus 11 Exhaust port 12 Reaction container 12a Cylindrical container 12b Cover part 13 Substrate holder 14 Substrate 15 Cylindrical shield 16 Annular shield 17 Substrate holder fixture 18 O-ring 19 Vaporizer 21 Gas of silicon alkoxide containing gas Supply pipe 21a Supply pipe body 21b Tip opening unit 21c, 21d, 21e, 21f, 21g, 21h, 21i, 21j, 21k Tip opening unit 22 Gas supply pipe for oxygen-containing gas 22a Supply pipe body 22b Tip opening unit 30 Heating tool 31 , 32, 33 Heating unit 36 Heating tool 41, 42, 43 Heating unit control device 46 Heating tool control device 51a, 51b, 51c Gas cylinder 52a, 52b, 52c Manual valve 53a, 53b, 53c Pressure sensor 54a, 54b, 54c 54d Air operated Valve 55a, 55b, 55c, 55d, 55e Mass flow controller 71 Silicon alkoxide-containing gas supply port 72 Oxygen-containing gas supply port 73 Reaction accelerator-containing gas supply port 74 Carrier gas supply port 80 Mixing chamber 81, 82 Wall body 81a Through hole 82a Opening 91, 92, 93 Partition 91a, 92a, 93a Through hole 101, 102, 103, 104, 105 Support

Claims (11)

A reaction vessel having an exhaust port, a substrate holder mounted in the reaction vessel, a surface of a substrate supported by the substrate holder for supplying an oxygen-containing gas into the reaction vessel, or a substrate on a plane including the substrate surface An oxygen-containing gas supply pipe disposed with a tip opening portion directed through the space, a silicon alkoxide-containing gas supply port for supplying a gas containing silicon alkoxide into the reaction vessel, and a reaction in the reaction vessel Including a reaction accelerator supply port for supplying a gas containing a promoter, and each of the silicon alkoxide-containing gas supply port and the reaction accelerator supply port is located on the same end side in the reaction vessel with respect to the mounting position of the substrate holder An apparatus for producing an open crystal thin film under atmospheric pressure,
The reaction vessel is a cylindrical reaction vessel arranged horizontally, and
The cylindrical reaction vessel includes a silicon alkoxide-containing gas in which the openings between the silicon alkoxide-containing gas supply port and the reaction accelerator supply port and the mounting position of the substrate holder are partitioned by a wall having an opening. A quartz thin film manufacturing apparatus, wherein a mixing chamber is formed for mixing the reaction accelerator and the reaction accelerator prior to contact with the oxygen-containing gas . The crystal thin film manufacturing apparatus according to claim 1, wherein a heating tool is disposed outside the cylindrical reaction vessel . The crystal thin film manufacturing apparatus according to claim 2, wherein the heating tool is divided into a plurality of heating units along the longitudinal direction of the cylindrical reaction vessel , and the heating conditions of each heating unit are controlled independently of each other. A cylindrical shield whose inner surface is formed of a material inert to silicon oxide in a gas phase is detachably mounted in the reaction vessel, and the substrate holder is placed inside the cylindrical shield. The crystal thin film manufacturing apparatus according to claim 1, which is provided . 5. The crystal thin film manufacturing apparatus according to claim 4, wherein the material inert to the silicon oxide in the gas phase is aluminum oxide, silicon carbide, or trisilicon tetranitride. The crystal thin film manufacturing apparatus according to claim 4 or 5, wherein a tip opening of a gas supply pipe for oxygen-containing gas is disposed inside the cylindrical shield. The crystal thin film manufacturing apparatus according to claim 1, wherein the oxygen-containing gas supply pipe includes a gas supply pipe main body and a tip opening unit that is detachably attached to a tip of the gas supply pipe main body. The crystal thin film manufacturing apparatus according to claim 1, wherein the supply port for the silicon alkoxide-containing gas is formed as a gas supply pipe whose tip reaches the inside of the mixing chamber. The crystal thin film manufacturing apparatus according to claim 8, wherein the gas supply pipe for the silicon alkoxide-containing gas includes a gas supply pipe main body and a tip opening unit that is detachably attached to the tip of the gas supply pipe main body. A cylindrical reaction vessel has all the gas supply ports and gas supply pipes at one end, a cylindrical vessel having an opening at the other end, an exhaust port, and the opening of the cylindrical vessel The crystal thin film manufacturing apparatus according to claim 1, further comprising: a lid portion detachably mounted on the quartz crystal. The crystal thin film manufacturing apparatus according to claim 1, wherein the substrate holder is disposed so as to support the substrate in an oblique direction with respect to the wall surface of the cylindrical reaction vessel.

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