JP5142111B2 - Sputtering equipment - Google Patents

Description

  The present invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus having a rotating cathode.

  The sputtering apparatus is a thin film forming apparatus that evaporates a target material in a gas phase with particles having high energy in a vacuum and deposits the target material on a base material or a substrate. As one type of sputtering apparatus, there is known a magnetron sputtering apparatus that can increase the efficiency of sputtering by confining plasma by a magnetic field. When the target is fixed in such a magnetron sputtering apparatus, since the consumption of the target is not uniform, a so-called race track is generated. As a sputtering apparatus that eliminates such a racetrack, there is known a magnetron sputtering apparatus that carries a target on the surface of a cylindrical cathode and has an axial direction as a rotation center (see Patent Documents 1 to 5).

  In addition, when a metal compound thin film such as a metal oxide or metal nitride is formed using a sputtering apparatus, the same material as the metal compound to be formed as the target material is used, and the main metal compound to be formed as the target material is used. Sometimes the component metal is used. When a metal is used as the target material, the metal compound is sputtered and then reacted with a reactive gas such as oxygen or nitrogen to form a metal compound thin film.

  However, in the above-described sputtering apparatus, when a metal compound is used as a target material, the sputtering rate of metal atoms from the target material is significantly reduced as compared with a case where the metal material is used as a target material. For this reason, there is a problem that a sufficiently high thin film deposition rate cannot be obtained industrially. Further, when the metal compound of the target material does not have conductivity, it is necessary to use a high frequency power source as a power source for the sputtering apparatus. For this reason, particularly when a large-sized cathode is used, there is a problem that stable discharge cannot be obtained, and other devices are affected by high-frequency leakage.

  On the other hand, when a compound thin film is formed by reacting with a reactive gas such as oxygen or nitrogen introduced using a target made of a metal material, the pressure (partial pressure) of the reactive gas is set on the substrate (substrate). It is necessary to increase the height of the compound thin film so that it can be formed. However, under such conditions, a compound layer is naturally formed on the surface of the target, and as in the case of using a target made of a metal compound, the sputtering rate is significantly reduced, and a high thin film deposition rate cannot be obtained. .

In addition, when a compound is formed on the target surface in this way, charge accumulates in a portion of the target surface that is not particularly conductive, and this is instantly released for some reason, causing abnormal discharge, so-called arcing (micro arcing). , Foreign matter formation was induced in the formed thin film.
Japanese Patent Laid-Open No. 6-158312 U.S. Pat. No. 4,417,968 European Patent Application Publication No. 0119631 International Publication No. 91/07519 Pamphlet International Publication No. 91/07521 Pamphlet

  As described above, the decrease in the sputtering rate and the decrease in the thin film deposition rate that occur when using a metal target is particularly noticeable when oxygen gas is used as the reactive gas, and is known as mode transition. A certain amount of time is required for the formation of the compound layer on the target surface that causes the mode transition, and this depends on the discharge power during sputtering, the size of the exhaust pump of the sputtering apparatus, in other words, the exhaust rate for the reactive gas, etc. It is known to be affected.

  This invention is made | formed in view of such a condition, The objective is to provide the sputtering device which improves the productivity of a compound thin film.

  In order to solve the above-described problems, a sputtering apparatus according to an aspect of the present invention includes a chamber that can be maintained in a low-pressure atmosphere from the outside, a holding unit that holds the substrate in the chamber, and a substrate that is held by the holding unit A rotating rotating cathode provided so that the peripheral surfaces thereof face each other, a cylindrical rotating cathode to which power for sputtering the target material on the surface is supplied, and a metal material is supplied to the surface of the rotating cathode A gas supply chamber between the film forming chamber provided with the holding unit and the material supply chamber provided with the material supply unit, and a gap where the rotary cathode can rotate. A gas shielding member having an opening in which the rotating cathode is disposed, a reactive gas supply path connected to the film forming chamber and supplying a reactive gas that reacts with the sputtered target material to form a compound; The Obtain. The material supply means newly supplies a metal material of the same type as the target material to the surface of the sputtered rotating cathode.

  Of the target on the surface of the rotating cathode, the portion sputtered in the film forming chamber is exposed to a reactive gas in the film forming chamber. In order for the reactive gas to react with the sputtered target surface to produce a compound, it takes time to be exposed to the reactive gas to some extent. However, according to this aspect, the sputtered portion of the target moves to the material supply chamber side by the rotation of the rotating cathode. The gas shielding member provided between the film formation chamber and the material supply chamber regulates the movement of the reactive gas supplied to the film formation chamber to the material supply chamber. Exposure to the reactive gas in the supply chamber is suppressed. In addition, in the material supply chamber, the formation of a compound on the surface of the target is suppressed by supplying a new metal material to the surface of the target including the sputtered portion of the target. Here, the metal material can be a metal or a metal slightly combined with oxygen, nitrogen, or the like.

  The rotating cathode may be supplied with pulsed power having a negative voltage applied when substantially performing sputtering. Thereby, accumulation of electric charges on the target surface can be mitigated, and abnormal discharge can be suppressed.

  The material supply means may have a sputtering cathode. Thereby, a film having relatively high adhesion can be formed on the rotating cathode at high speed.

  The sputtering cathode may have a plurality of cathodes on which different types of target materials can be arranged. As a result, an alloy target material can be formed on the rotating cathode. In addition, by controlling the sputtering conditions for the target material of each cathode of the sputtering cathode, the component ratio of the alloy target on the rotating cathode can be arbitrarily changed. As a result, the composition ratio of a plurality of components contained in the compound deposited on the substrate in the deposition chamber can be changed without changing the target material of the sputtering cathode.

  The sputtering cathode may have a cylindrical shape whose peripheral surface rotates while facing the rotating cathode. As a result, the target material can be used efficiently and the life of the target can be extended.

  The sputtering cathode may be provided with a magnet on the side opposite to the surface on which the target material is provided. As a result, it can be used even at a high frequency, and it can be controlled so that plasma is not generated in the vicinity of the rotating cathode. As a result, the metal material can be supplied without damaging the target on the rotating cathode.

  The sputtering cathode may be supplied with pulsed power having a negative voltage applied when substantially performing sputtering. Thereby, accumulation of electric charges on the target surface can be mitigated, and abnormal discharge can be suppressed.

  The phase of power applied to the rotating cathode may be different from the phase of power applied to the sputtering cathode. This suppresses reverse sputtering of the target material sputtered from the sputtering cathode toward the rotating cathode, thereby improving the sputtering efficiency.

  The material supply chamber may be provided with an inert gas supply path through which an inert gas or a mixed gas of an inert gas and a reducing gas is supplied. Thereby, even if the reactive gas slightly leaks into the material supply chamber, the target exposed to the material supply chamber side is prevented from reacting with the reactive gas. In particular, when the reactive gas is oxygen, the partial pressure of the reactive gas in the material supply chamber can be reduced by reducing with the reducing gas. Here, examples of the reducing gas include hydrogen, acetylene, and methane.

  The gas shielding member may be provided with an exhaust portion for exhausting the gas in the chamber to the outside on the side surface of the opening facing the rotating cathode. Thereby, it is possible to prevent the reactive gas in the film forming chamber from slightly leaking from the gap of the opening of the gas shielding member toward the material supply chamber.

  The reactive gas supply path may be connected to a reactive gas supply source including at least one of oxygen, nitrogen, fluorine, ethylene, acetylene, benzene, tetrafluorocarbon, tetrafluoroethylene, and methane.

  A facilitating means for promoting ionization or radicalization of the reactive gas may be further provided. As a result, the amount of reactive gas required for compound formation can be suppressed, and a thin film deposited on a substrate can be sufficiently oxidized or nitrided with a lower reactive gas flow rate and close to the stoichiometric ratio. Can be obtained. At the same time, it is possible to suppress compound formation on the surface of the metal or the like on the rotating cathode serving as the target material.

  The rotating cathode may be provided with a magnet on its inner peripheral side. As a result, it can be used even at a high frequency, and it can be controlled so that plasma is not generated in the vicinity of the rotating cathode. As a result, sputtering is possible without damaging the compound film on the substrate in the holding portion.

  The material supply means may have a vapor deposition source for evaporating the thin film material. The material supply means is supplied with a raw material containing at least one of a metal fluoride, a metal chloride, a metal hydride and an organometallic compound, which is formed as a thin film material on the surface of the rotating cathode by vapor phase growth. You may have a raw material supply path.

  A combination of the above-described elements as appropriate can also be included in the scope of the invention for which patent protection is sought by this patent application.

  According to the present invention, the productivity of the compound thin film can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of the overall configuration of the sputtering apparatus according to the first embodiment. A sputtering apparatus 10 according to the present embodiment includes a chamber 12 that can be maintained in a low-pressure atmosphere from the outside, a holding unit 16 that holds a base material 14 such as a glass substrate or a silicon wafer in the chamber 12 and also serves as an anode, A rotatable rotating cathode 18 provided so that the peripheral surface thereof faces the base material 14 held by the holding unit 16, and a metal material supply means capable of supplying a thin film material such as metal to the surface of the rotating cathode 18 A gap 26 that restricts the movement of gas between the auxiliary cathode 20, the film forming chamber 22 provided with the holding unit 16, and the metal material supply chamber 24 provided with the auxiliary cathode 20, and allows the rotating cathode 18 to rotate. A gas shielding member 30 having a rectangular opening 28 in which a rotating cathode is disposed and a metal compound formed by reacting with a sputtered target material connected to the film formation chamber 22. It comprises a reactive gas supply path 32 for supplying a reactive gas to form a. The reactive gas supply path 32 is connected to a reactive gas supply source (not shown) including at least one of oxygen, nitrogen, fluorine, ethylene, acetylene, benzene, tetrafluorocarbon, tetrafluoroethylene, and methane. Yes.

  The rotating cathode 18 is provided with a cylindrical sleeve 34 to which power for sputtering the target material on the surface is supplied, a driving unit (not shown) that rotationally drives the sleeve 34, and a magnetic field provided on the inner peripheral side of the sleeve 34. And a generated magnet 36. By restricting the region where the plasma is generated by such a magnet 36, the plasma is confined in the vicinity of the target, and the sputtering rate is improved. Moreover, it can be used even at a high frequency, and it can be controlled so that plasma is not generated in the vicinity of the base material, and sputtering can be performed without damaging the metal compound film on the base material 14 in the holding portion 16.

  Although the rotary cathode 18 having a target material previously formed on the surface of the sleeve 34 may be used, the target material is formed on the exposed surface of the sleeve 34 made of aluminum or SUS by the auxiliary cathode 20 to form the rotary cathode 18. It may be used. Examples of the target material include materials that can be components of high refractive index materials such as titanium, indium, tin, zinc, cerium, bismuth, zirconium, niobium, and tantalum. Further, silicon or the like may be used as a target material as necessary. As the reactive gas, for example, oxygen may be appropriately selected when an oxide film is formed, and nitrogen may be selected when a nitride film is formed. Hereinafter, a case where the target material is titanium, the reactive gas is oxygen, and the resultant compound thin film is titanium oxide will be described.

  A portion of the target 38 on the surface of the rotating cathode 18 that is sputtered in the film forming chamber 22 is exposed to oxygen gas in the film forming chamber 22. Therefore, when the target made of titanium is oxidized, the film forming rate by sputtering is extremely reduced. However, in order for oxygen to react with the surface of the sputtered titanium target 38 to generate titanium oxide, it takes some time to be exposed to oxygen gas. In other words, it is possible to suppress oxidation of the titanium target 38 by shortening this time.

  Therefore, in the sputtering apparatus 10 according to the present embodiment, the sputtered portion of the target 38 moves to the metal material supply chamber 24 side by the rotation of the rotating cathode 18. The gas shielding member 30 provided between the film formation chamber 22 and the metal material supply chamber 24 restricts the oxygen gas supplied to the film formation chamber 22 from moving to the metal material supply chamber 24. Therefore, the portion 38 a of the sputtered target 38 is moved to the metal material supply chamber 24 side by rotation, so that the portion 38 a of the target 38 is suppressed from being exposed to oxygen gas in the metal material supply chamber 24. In addition, titanium oxide may be formed on the surface of the target 38 by supplying titanium, which is a metal material, to the surface of the target 38 including the sputtered portion 38 a of the target 38 in the metal material supply chamber 24. It is suppressed. The material of the gas shielding member 30 is preferably stainless steel, copper, or aluminum alloy, and may be water-cooled as necessary. Note that the flow of the reactive gas from the film forming chamber 22 to the metal material supplying chamber 24 is suppressed by slightly increasing the pressure in the metal material supplying chamber 24 from the pressure in the film forming chamber 22.

  The rotating cathode 18 is supplied with pulsed power having a negative voltage applied when sputtering is substantially performed. Thereby, the accumulation of charges on the surface of the target 38 is alleviated, and abnormal discharge is suppressed. The power source for supplying power to the rotating cathode may be a direct current method or an alternating current method.

  The auxiliary cathode 20 newly supplies the same metal material as the target material to the surface of the sputtered rotating cathode 18. Specifically, the auxiliary cathode 20 includes a conductive casing 42 on which the target 40 is placed and functions as a sputtering cathode, and a magnet 44 that is provided inside the casing 42 and generates a magnetic field. Thereby, a film having relatively high adhesion can be formed on the rotating cathode 18 at high speed. The auxiliary cathode 20 may be a cylindrical rotating cathode that rotates while its peripheral surface faces the rotating cathode 18 instead of the fixed sputtering cathode as shown in FIG. As a result, the target material can be used efficiently and the life of the target can be extended.

  Since the auxiliary cathode 20 is provided with the magnet 44 on the side opposite to the surface on which the target 40 is provided, it can be used even at high frequencies and can be controlled so that plasma is not generated near the rotating cathode 18. As a result, the metal material can be supplied without damaging the target 38 on the rotating cathode 18.

  The auxiliary cathode 20 is supplied with pulsed power having a negative voltage applied when sputtering is substantially performed. Thereby, the accumulation of charges on the surface of the target 40 is alleviated, and abnormal discharge is suppressed.

  Note that power may be supplied from a power source (not shown) so that the phase of the power applied to the rotating cathode 18 and the phase of the power applied to the auxiliary cathode 20 are different. Thereby, the reverse sputtering of the target material sputtered from the auxiliary cathode 20 toward the rotating cathode 18 is suppressed, and the sputtering efficiency is improved.

  More specifically, when a sputtering cathode is used as the metal material supply source, the metal supplied from the auxiliary cathode 20 to the rotating cathode 18 may be sputtered on the metal material supply chamber 24 side. This is because the discharge on the rotating cathode 18 occurs on the film forming chamber 22 side facing the base material 14 which is the front surface of the magnet 36, but at the same time, discharge occurs on the surface on the metal material supply chamber 24 side. A magnet for forming a magnetic circuit is not provided on the metal material supply chamber 24 side of the rotating cathode 18, and the discharge is low density. Sputtering due to this discharge can usually be ignored. However, if this cannot be ignored, the discharge in the metal material supply chamber 24 can be suppressed by a method in which power is not supplied to the rotating cathode 18 during the period in which power is supplied to the auxiliary cathode 20.

  Further, the sputtering from the auxiliary cathode 20 to the rotating cathode 18 may be performed continuously or intermittently according to the thickness of the target 38 on the rotating cathode 18 or the like. Therefore, the sputtering apparatus 10 may include a measuring device that measures the thickness of the target 38 on the rotating cathode 18.

  The metal material supply chamber 24 is provided with an inert gas supply path 46 through which an inert gas such as argon or a mixed gas of inert gas and hydrogen gas is supplied. Thereby, even if oxygen gas, which is a reactive gas, slightly leaks into the metal material supply chamber 24, the reaction of the target 38 exposed on the metal material supply chamber 24 side with the oxygen gas is suppressed. In particular, when the reactive gas is oxygen, the partial pressure of the oxygen gas in the metal material supply chamber 24 can be reduced by reduction with hydrogen.

  In the gas shielding member 30 according to the present embodiment, an exhaust portion 48 that exhausts the gas in the chamber 12 to the outside is provided on the side surface of the opening 28 that faces the rotating cathode 18. Thereby, the reactive gas in the film forming chamber 22 can be prevented from slightly leaking from the gap 26 of the opening 28 of the gas shielding member 30 toward the metal material supply chamber 24. Specifically, as shown in FIG. 1, the exhaust unit 48 exhausts the gas that has flowed into the intermediate chamber 47 of the double gas shielding member 30 to the outside. The pressure in the intermediate chamber 47 is kept lower than that in the film formation chamber 22 or the metal material supply chamber 24. Thereby, the reactive gas introduced into the film formation chamber 22 is suppressed from flowing into the metal material supply chamber 24.

  The film formation chamber 22 and the metal material supply chamber 24 are provided with discharge ports 50 and 52 for discharging the inert gas and the reactive gas introduced therein. Separate evacuation devices are connected to the discharge ports 50 and 52, respectively. This makes it possible to control the pressures in the film formation chamber 22 and the metal material supply chamber 24, respectively. For example, the pressure in the metal material supply chamber 24 is slightly higher than that in the film formation chamber 22, so that the film formation chamber 22 is increased. The reactive gas inside is prevented from flowing into the metal material supply chamber 24.

  As described above, the sputtering apparatus 10 supplies a metal material in addition to the rotating cathode 18 so that the metal can be constantly supplied to the surface of the target 38 in order to suppress the formation of the compound thin film on the surface of the target 38. An auxiliary cathode 20 is provided as a source. Further, the gas shielding member 30 makes it possible to make the reactive gas partial pressure in the discharge space of the metal material supply chamber 24 almost zero, and it is possible to supply metal from the metal material supply source to the rotating cathode 18. Since the metal thin film is always formed on the target 38 of the rotating cathode 18 by rotating the rotating cathode 18 constantly or intermittently, the reduction of the compound thin film deposition rate due to the formation of the compound thin film on the target 38 and Instability of the sputtering process due to abnormal discharge such as arcing is suppressed.

  Further, the metal supplied from the auxiliary cathode 20 is exposed to a reactive gas in the film forming chamber 22, and a compound is formed on the surface thereof. However, as described above, the formation of the compound takes about several seconds, and the time becomes longer as the exhaust speed of the vacuum pump connected to the exhaust port 50 becomes larger.

  Accordingly, it is possible to suppress the formation of the compound on the rotating cathode 18 by appropriately setting the discharge power, the reactive gas partial pressure, and the exhaust speed, thereby reducing the deposition rate (film formation rate) of the compound thin film. Can be suppressed. When the partial pressure of the reactive gas in the film formation chamber 22 is lowered, sufficient reaction may not occur on the substrate, and the deposited thin film may have a composition ratio less than a desired ratio.

  In order to increase the activity of the reactive gas, the reactive gas supply path 32 may be provided with a promoting means for promoting ionization or radicalization of the reactive gas. As a result, the amount of reactive gas required for compound formation can be suppressed, and a thin film deposited on a substrate can be sufficiently oxidized or nitrided with a lower reactive gas flow rate and close to the stoichiometric ratio. Can be obtained. At the same time, it is possible to suppress the compound formation on the metal surface on the rotating cathode as the target material. For example, voltage application means may be provided in the middle of the reactive gas supply path 32 or in the vicinity of the outlet so that auxiliary discharge is possible. As described above, the sputtering apparatus 10 according to the present embodiment achieves high-speed and stable formation of the metal compound thin film.

(Titanium oxide film formation method)
Next, a method for forming a titanium oxide thin film on the substrate using the sputtering apparatus 10 will be described in detail. First, a titanium target 40 is installed on the auxiliary cathode 20 provided in the metal material supply chamber 24. A mixed gas obtained by mixing 5 mol% of hydrogen gas, which is a reducing gas, with argon gas, which is an inert gas, is introduced into the metal material supply chamber 24 from the inert gas supply path 46. The pressure of the mixed gas at that time is 0.5 Pa. A glass plate is installed as a base material 14 in a substrate holder as a holding unit 16 installed in a substrate transport mechanism (not shown).

  On the other hand, a mixed gas of argon gas and oxygen gas is introduced from the reactive gas supply path 32 into the film forming chamber 22 where the rotating cathode 18 is provided. At this time, the pressure of the mixed gas is 0.4 Pa, and the ratio of argon gas to oxygen gas is 1: 1. The rotating cathode 18 is rotated at 3 to 30 rpm and DC power is supplied to the auxiliary cathode 20 to cause metal sputtering.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 18 to cause discharge. After the discharge is stabilized, the glass passes through the front surface of the rotating cathode 18 by the substrate transport mechanism, whereby a thin film is formed. A titanium oxide thin film having a thickness of 95 nm could be deposited when the glass conveying speed was 60 mm / min. The refractive index was 2.46 for light having a wavelength of 633 nm. As described above, by using the sputtering apparatus 10 according to the present embodiment, a titanium oxide thin film, which has conventionally been difficult to form at high speed, can be formed at high speed.

(Silicon oxide)
Next, a method for forming a silicon oxide thin film on the substrate using the sputtering apparatus 10 will be described in detail. First, a silicon target to which boron is added as a metal supply source is installed on the auxiliary cathode 20 provided in the metal material supply chamber 24. A mixed gas obtained by mixing 5 mol% of hydrogen gas, which is a reducing gas, with argon gas, which is an inert gas, is introduced into the metal material supply chamber 24 through an inert gas supply path 46. The pressure of the mixed gas at that time is 0.5 Pa. A glass plate is installed as a base material 14 in a substrate holder as a holding unit 16 installed in a substrate transport mechanism (not shown).

  On the other hand, a mixed gas of argon gas and oxygen gas is introduced from the reactive gas supply path 32 into the film forming chamber 22 where the rotating cathode 18 is provided. At this time, the pressure of the mixed gas is 0.4 Pa, and the ratio of argon gas to oxygen gas is 1: 1. The rotating cathode 18 is rotated at 3 to 30 rpm and DC power is supplied to the auxiliary cathode 20 to cause metal sputtering.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 18 to cause discharge. After the discharge is stabilized, the glass passes through the front surface of the rotating cathode 18 by the substrate transport mechanism, whereby a thin film is formed. When the glass conveyance speed was 60 mm / min, a 72 nm thick silicon oxide thin film could be deposited. The refractive index was 1.43 for light having a wavelength of 633 nm. Thus, by using the sputtering apparatus 10 according to this embodiment, a silicon oxide thin film can be formed at a high speed.

(Second Embodiment)
FIG. 2 is a schematic cross-sectional view of the overall configuration of the sputtering apparatus 110 according to the second embodiment. The sputtering apparatus 110 according to the present embodiment is different from the first embodiment in that an evaporation source is used as a metal material supply source. In the following, points different from the first embodiment will be described in detail, and the same points will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

The sputtering apparatus 110 according to the present embodiment includes an evaporation source 120 as a metal material supply source provided in the metal material supply chamber 24, and a metal material supply chamber 24 provided with the film formation chamber 22 and the evaporation source 120. And a gas shielding member 130 having a rectangular opening 28 in which the rotary cathode 18 is disposed with a gap 26 in which the rotary cathode 18 can rotate. Further, the metal material supply chamber 24 is connected to a vacuum pump through the discharge port 52 in order to maintain an atmosphere of about 10 ⁻³ Pa, which is a sufficiently low pressure for the metal material to cause vapor deposition.

  The vapor deposition source 120 is a container 122 on which a metal material 124 such as titanium to be evaporated is placed, and is heated by a method such as resistance heating, electron beam, high frequency induction, or laser. The heated metal material 124 is vaporized or sublimated and deposited on the surface of the rotating cathode 18. The vapor deposition from the vapor deposition source 120 to the rotary cathode 18 may be performed continuously or intermittently according to the thickness of the target 38 on the rotary cathode 18 and the like. The rotary cathode 18 having a target material previously formed on the surface of the sleeve 34 may be used. However, the target material is formed on the exposed surface of the sleeve 34 made of aluminum or SUS by the vapor deposition source 120 to form the rotary cathode 18. It may be used.

  As described above, in the sputtering apparatus 110 according to the present embodiment, the sputtered portion 38 a of the target 38 moves to the metal material supply chamber 24 side by the rotation of the rotating cathode 18. The gas shielding member 130 provided between the film formation chamber 22 and the metal material supply chamber 24 restricts the oxygen gas supplied to the film formation chamber 22 from moving to the metal material supply chamber 24. Therefore, the portion 38 a of the sputtered target 38 is suppressed from being exposed to oxygen gas in the metal material supply chamber 24. In addition, titanium oxide may be formed on the surface of the target 38 by supplying titanium, which is a metal material, to the surface of the target 38 including the sputtered portion 38 a of the target 38 in the metal material supply chamber 24. It is suppressed.

Next, a method of forming a titanium oxide thin film on the substrate using the sputtering apparatus 110 will be described in detail. First, the container 122 of the vapor deposition source 120 provided in the metal material supply chamber 24 is filled with titanium. At that time, the metal material supply chamber 24 is maintained so that the pressure becomes an atmosphere of 10 ⁻² Pa or less. Further, a glass plate is installed as a base material 14 in a substrate holder as a holding unit 16 installed in a substrate transport mechanism (not shown).

  On the other hand, a mixed gas of argon gas and oxygen gas is introduced from the reactive gas supply path 32 into the film forming chamber 22 where the rotating cathode 18 is provided. At this time, the pressure of the mixed gas is 0.4 Pa, and the ratio of argon gas to oxygen gas is 1: 1. The rotary cathode 18 is rotated at 3 to 30 rpm and the vapor deposition source 120 is heated to evaporate titanium as the metal material 124. At this time, the evaporation rate is controlled to be kept at a predetermined value using a quartz crystal vibration monitor.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 18 to cause discharge. After the discharge is stabilized, the glass passes through the front surface of the rotating cathode 18 by the substrate transport mechanism, whereby a thin film is formed. A titanium oxide thin film having a thickness of 95 nm could be deposited when the glass conveying speed was 60 mm / min. The refractive index was 2.37 for light having a wavelength of 633 nm. As described above, by using the sputtering apparatus 110 according to this embodiment, a titanium oxide thin film, which has conventionally been difficult to form at high speed, can be formed at high speed.

(Third embodiment)
FIG. 3 is a schematic cross-sectional view of the overall configuration of the sputtering apparatus 210 according to the third embodiment. The sputtering apparatus 210 according to the present embodiment is different from the first embodiment in that a raw material supply path for supplying a metal material in a gas state is provided as a metal material supply source. In the following, points different from the first embodiment will be described in detail, and the same points will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

  The sputtering apparatus 210 according to the present embodiment includes a raw material supply path 220 as a metal material supply source provided in the metal material supply chamber 24, a heater 222 that heats the raw material gas supplied from the raw material supply path 220, and a raw material A square in which the rotating cathode 18 is disposed with a gap 26 in which the rotating cathode 18 can rotate while restricting the movement of gas between the metal material supply chamber 24 provided with the supply path 220 and the film forming chamber 22. And a gas shielding member 130 having an opening 28 formed therein.

  In the raw material supply path 220, nozzles are arranged so that the raw material gas is directed to the rotating cathode 18. As the source gas, metal fluoride, metal chloride, metal hydride, organometallic compound, or the like is used. Specifically, titanium chloride is exemplified. The liquid or gaseous raw material supplied from the raw material supply path 220 is heated by the heater 222, reduced and decomposed by a chemical reaction on the surface of the rotating cathode 18, and deposited on the rotating cathode 18 as a metal. The supply of the raw material from the raw material supply path 220 to the rotary cathode 18 may be performed continuously or intermittently according to the thickness of the target 38 on the rotary cathode 18 and the like. Alternatively, the rotary cathode 18 having a target material previously formed on the surface of the sleeve 34 may be used, but the target material is formed from the raw material supplied from the raw material supply path 220 on the exposed surface of the sleeve 34 made of aluminum or SUS. Thus, the rotating cathode 18 may be used.

  As described above, in the sputtering apparatus 210 according to the present embodiment, the sputtered portion 38 a of the target 38 moves to the metal material supply chamber 24 side by the rotation of the rotating cathode 18. The gas shielding member 130 provided between the film formation chamber 22 and the metal material supply chamber 24 restricts the oxygen gas supplied to the film formation chamber 22 from moving to the metal material supply chamber 24. Therefore, the portion 38 a of the sputtered target 38 is suppressed from being exposed to oxygen gas in the metal material supply chamber 24. In addition, titanium oxide may be formed on the surface of the target 38 by supplying titanium, which is a metal material, to the surface of the target 38 including the sputtered portion 38 a of the target 38 in the metal material supply chamber 24. It is suppressed. In addition, since the sputtering apparatus 210 according to the present embodiment can continuously supply the raw material from the outside through the raw material supply path 220, the base material 14 is exchanged in the film formation chamber 22 separated by the gas shielding member 130. By doing this, continuous film formation on a plurality of substrates can be performed.

  Next, a method for forming a titanium oxide thin film on the substrate using the sputtering apparatus 210 will be described in detail. First, titanium chloride is introduced into the metal material supply chamber 24 from the raw material supply path 220 using argon gas as a carrier. Further, a glass plate is installed as a base material 14 in a substrate holder as a holding unit 16 installed in a substrate transport mechanism (not shown).

  On the other hand, a mixed gas of argon gas and oxygen gas is introduced from the reactive gas supply path 32 into the film forming chamber 22 where the rotating cathode 18 is provided. At this time, the pressure of the mixed gas is 0.4 Pa, and the ratio of argon gas to oxygen gas is 1: 1. The rotating cathode 18 is rotated at 3 to 30 rpm and the surface of the rotating cathode 18 is heated to 400 ° C. by the heater 222. As a result, metallic titanium is deposited on the surface of the rotating cathode 18.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 18 to cause discharge. After the discharge is stabilized, the glass passes through the front surface of the rotating cathode 18 by the substrate transport mechanism, whereby a thin film is formed. A titanium oxide thin film having a thickness of 95 nm could be deposited when the glass conveying speed was 60 mm / min. The refractive index was 2.35 for light having a wavelength of 633 nm. As described above, by using the sputtering apparatus 110 according to this embodiment, it is possible to form a titanium oxide thin film, which has conventionally been difficult to form at high speed, at high speed without replacing the metal material supply means. It becomes possible.

(Fourth embodiment)
FIG. 4 is a schematic cross-sectional view of the overall configuration of the sputtering apparatus 310 according to the fourth embodiment. The sputtering apparatus 310 according to this embodiment is different from the first embodiment in that it includes a plurality of metal material supply sources. In the following, points different from the first embodiment will be described in detail, and the same points will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

  The sputtering apparatus 310 according to the present embodiment includes a holding unit 16 that holds the base material 14 and also serves as an anode, a rotating cathode 18, and a plurality of metal material supply units that can supply a metal material to the surface of the rotating cathode 18. Of the auxiliary cathodes 320 and 330, the gas deposition chamber 22 and the metal material supply chamber 24, and a square in which the rotating cathode 18 is disposed with a gap 26 in which the rotating cathode 18 can rotate. The gas shielding member 130 in which the opening 28 is formed and the reactive gas supply path 32 are provided.

  The auxiliary cathode 320 includes a conductive casing 324 on which the target 322 is placed and functions as a sputtering cathode, and a magnet 326 that is provided inside the casing 324 and generates a magnetic field. The auxiliary cathode 330 includes a conductive casing 334 on which the target 332 is placed and functions as a sputtering cathode, and a magnet 336 provided inside the casing 334 and generating a magnetic field. Here, the material of the target 322 disposed on the auxiliary cathode 320 and the material of the target 332 disposed on the auxiliary cathode 330 are different.

  Thereby, an alloy target material can be deposited on the rotating cathode 18. Further, by controlling the sputtering conditions for the target materials of the auxiliary cathodes 320 and 330, the component ratio of the alloy target on the rotating cathode 18 can be arbitrarily changed. As a result, the composition ratio of the plurality of metal components contained in the metal compound deposited on the substrate 14 in the deposition chamber 22 can be changed without replacing the target material of the auxiliary cathodes 320 and 330.

  In the sputtering apparatus 310, the gas shielding member 130 is disposed above the rotation axis X of the rotating cathode 18. As a result, the two auxiliary cathodes 320 and 330 can be arranged on the side of the rotating cathode 18. As a result, the height of the metal material supply chamber 24 can be suppressed, and the entire apparatus including the chamber 12 can be reduced in size.

(Fifth embodiment)
FIG. 5 is a schematic cross-sectional view of the overall configuration of a sputtering apparatus 410 according to the fifth embodiment. The sputtering apparatus 410 according to the present embodiment is configured such that a plurality of main parts of the sputtering apparatus 110 according to the first embodiment are arranged so that the substrate can be moved between the apparatuses. In the following, points different from the first embodiment will be described in detail, and the same points will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

  The sputtering apparatus 410 includes rotating cathodes 412 and 414 and auxiliary cathodes 416 and 418. The functions of the rotating cathode and the auxiliary cathode are the same as in the above-described embodiment. In the present embodiment, a method of forming a titanium oxide / silicon oxide optical multilayer thin film using two pairs of rotating cathodes and auxiliary cathodes will be described.

  Of the two auxiliary cathodes installed in the metal material supply chamber 420, a titanium target 422 is installed on one auxiliary cathode 416. The other auxiliary cathode 418 is provided with a silicon target 424 to which boron is added. A mixed gas obtained by mixing 5 mol% of hydrogen gas, which is a reducing gas, with argon gas, which is an inert gas, is introduced into the metal material supply chamber 420, and the pressure is set to 0.5 Pa. A glass plate is installed as a base material 14 on a substrate holder installed in a substrate transport mechanism (not shown). The substrate transport mechanism is configured to move the base material 14 in the left-right direction in the figure.

  On the other hand, a mixed gas of argon gas and oxygen gas is introduced into a film formation chamber 426 provided with rotating cathodes 412 and 414 from a reactive gas supply path (not shown). A mixed gas of argon gas and oxygen gas is introduced into the thin film deposition chamber in front of the rotating cathodes 412 and 414, the pressure is 0.4 Pa, and the ratio of argon gas to oxygen gas is 1: 1. The rotating cathode 412 is rotated at 3 to 30 rpm and 50 kHz pulsed DC power is supplied to the auxiliary cathode 416 to cause sputtering of titanium metal, thereby depositing titanium metal on the surface of the rotating cathode 412.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 412 to cause discharge. After the discharge becomes stable, the glass passes through the front surface of the rotating cathode 412 by the substrate transport mechanism, whereby a thin film is formed. A titanium oxide thin film having a designed film thickness is formed at a predetermined glass transport speed. After the formation of the titanium oxide thin film is completed, the pulsed DC power applied to the auxiliary cathode 416 and the rotating cathode 412 is stopped, and the discharge is stopped.

  Next, pulsed DC power of 50 kHz is supplied to the auxiliary cathode 418 on which the silicon target 424 to which boron is added is placed, sputtering of silicon metal is caused, and silicon metal is deposited on the surface of the rotating cathode 414.

  Next, 50 kHz pulsed DC power is supplied to the rotating cathode 414 to cause discharge. After the discharge becomes stable, the glass passes through the front surface of the rotating cathode 414 by the substrate transport mechanism, whereby a thin film is formed. A silicon oxide thin film having a designed film thickness is formed at a predetermined glass transport speed. After the formation of the silicon oxide thin film is completed, the pulsed DC power applied to the auxiliary cathode 418 and the rotating cathode 414 is stopped, and the discharge is stopped.

  The above operation is repeated a predetermined number of times to form a multilayer structure thin film having a predetermined thickness of each metal oxide. If the thickness of one of the metal oxide layers is different from the designed thickness (optical thickness), either form a thin film again or adjust the thickness of the upper metal oxide layer. This adjusts the optical properties of the multilayer thin film. The optical film thickness is measured using an optical monitor installed in the chamber.

FIG. 6 is a diagram showing characteristics of a multilayer optical film created by the sputtering apparatus according to the fifth embodiment. In the figure, the transmittance of the transparent body having an optical multilayer film in which titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) are laminated is shown for ultraviolet and infrared light. In the transparent body of the present embodiment, the number of thin films is eight. This transparent body had a visible light transmittance of 80% or more and an energy transmittance in the infrared region of 50% or less. In addition, by increasing the number of layers, it is possible to create a transparent body having higher visible high transmittance and lower ultraviolet and infrared light transmittance. For example, it comprises a multilayer thin film in which at least three layers of a high refractive index thin film having a refractive index of 2.35 or more and a low refractive index thin film having a refractive index of 1.4 to 1.65 are combined, and the average transmission in the visible light region. Manufacturing a transparent body having a transmittance of approximately 80% or more, a transmittance in the ultraviolet region of wavelength from 330 nm to 400 nm of 50% or less, and a transmittance in the infrared region of wavelength of 800 nm to 1100 nm of 30% or less. Can do. As the multilayer film of the multilayer optical film, Ta ₂ O ₅ and Nb ₂ O ₅ can be appropriately employed in addition to the above-described SiO ₂ and TiO ₂ .

(Sixth embodiment)
FIG. 7 is a schematic cross-sectional view of the overall configuration of the sputtering apparatus according to the sixth embodiment. Here, the gas supply / exhaust configuration and the substrate transport mechanism in each chamber will be described in particular, and the same components as those in the sputtering apparatus 10 according to the first embodiment will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

  In the chamber 512 according to this embodiment, a gate valve 513 is provided on the side surface of the film formation chamber 522 that communicates with a load lock chamber (not shown) to block the film formation chamber 522 from the load lock chamber. Then, the substrate 514 is transferred to or from the film formation chamber 522 by the substrate transfer mechanism 516 including a plurality of rollers. Oxygen gas is supplied to the region between the substrate 514 and the rotating cathode 18 from the reactive gas supply path 32 using argon gas as a carrier. In addition, a discharge port 50 connected to an exhaust pump for exhausting the reactive gas introduced into the film formation chamber 522 to the outside is provided on the lower surface of the film formation chamber 522. On the other hand, a mixed gas of argon gas and hydrogen gas is introduced into the metal material supply chamber 524 from the inert gas supply path 46. The metal material supply chamber 524 is provided with a discharge port 52 connected to an exhaust pump for exhausting the introduced mixed gas to the outside. Also by such a sputtering apparatus 510, the same effect as the first embodiment can be obtained.

  The present invention has been described above with reference to the above-described embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and the embodiments and examples are not limited thereto. What combined the structure suitably and the thing which substituted are also contained in this invention. Further, based on the knowledge of a person skilled in the art, it is possible to appropriately change the combination of the embodiments and the order of the embodiments and the order of the steps and various modifications such as design changes to the embodiments. Embodiments and examples to which such modifications are added can also be included in the scope of the present invention.

  For example, the case where the present invention is applied to film formation of ITO which is a transparent conductive film will be described. Reactive sputtering using a metal target is difficult to be used industrially because it causes instability of the target surface in a reactive process, and industrial production has been made by sputtering using an oxide target. It was. In this method, a large cost is required for sintering and forming the ITO target. On the other hand, by using the sputtering apparatus according to the above-described embodiment, instability in reactive sputtering for sputtering a metal layer that is not oxidized on the rotating cathode is suppressed, and an In—Sn alloy target An ITO thin film using can be formed. That is, in the above-described embodiment capable of suppressing instability in reactive sputtering, an ITO thin film with reduced cost can be obtained by using an inexpensive In—Sn alloy target with reduced sintering and molding costs as an auxiliary cathode. Can be formed. As a result, it greatly contributes to cost reduction in various parts and products using ITO thin films.

  Moreover, the case where this invention is applied to manufacture of a solar cell is demonstrated. Conventionally, amorphous or polycrystalline solar cells have been formed by a CVD method. This is because it is difficult to supply a silicon target material as a target in the sputtering method, and scattering of fine silicon particles from the target surface during sputtering is inevitable. On the other hand, since the silicon layer formed on the rotating cathode is a thin layer by using the sputtering apparatus according to the above-described embodiment, scattering of silicon fine particles due to stress from the surface is suppressed. Therefore, it is possible to form the silicon layer by sputtering, and at the same time, to take advantage of the characteristics of the sputtering method that it is possible to form a thin film with high density and high characteristics at a low temperature. As described above, according to the sputtering apparatus according to the present embodiment, it is not necessary to prepare a target which has been a defect of the silicon thin film formation by the sputtering method from the beginning, and it is possible to form a high-quality silicon thin film utilizing the features of the sputtering method. It becomes possible.

It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 1st Embodiment. It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 2nd Embodiment. It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 3rd Embodiment. It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 4th Embodiment. It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 5th Embodiment. It is a figure which shows the characteristic of the multilayer optical film created with the sputtering device which concerns on 5th Embodiment. It is a schematic sectional drawing of the whole structure of the sputtering device which concerns on 6th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Sputtering device, 12 Chamber, 14 Base material, 16 Holding part, 18 Rotating cathode, 20 Auxiliary cathode, 22 Deposition chamber, 24 Metal material supply chamber, 26 Gap, 28 Opening, 30 Gas shielding member, 32 Reactive gas Supply path, 34 sleeve, 36 magnet, 38, 40 target, 42 housing, 44 magnet, 46 inert gas supply path, 48 exhaust part, 50, 52 outlet, 110 sputtering apparatus, 120 vapor deposition source, 122 container, 124 Metal material, 130 gas shielding member, 210 sputtering device, 220 raw material supply path, 222 heater, 310 sputtering device, 320 auxiliary cathode, 322 target, 324 housing, 326 magnet, 330 auxiliary cathode, 332 target, 334 Housing, 336 magnet, 410 sputtering apparatus, 412 and 414 rotating cathode, 416 and 418 auxiliary cathode, 420 metal material supply chamber, 422 and 424 target, and 426 deposition chamber.

Claims (15)

A chamber that can be maintained in a lower-pressure atmosphere than the outside;
A holding unit for holding a substrate in the chamber;
A rotatable rotating cathode provided so that a peripheral surface thereof faces the substrate held by the holding unit, and a cylindrical rotating cathode to which power for sputtering the target material on the surface is supplied;
Material supply means capable of supplying a metal material to the surface of the rotating cathode;
While restricting the movement of gas between the film forming chamber provided with the holding unit and the material supply chamber provided with the material supply means, the rotary cathode has a gap that allows the rotary cathode to rotate. A gas shielding member having an opening to be disposed;
A reactive gas supply path connected to the film forming chamber and supplying a reactive gas that reacts with the sputtered target material to form a compound;
The material supply means newly supplies the metal material of the same type as the target material to the surface of the sputtered rotating cathode.
A sputtering apparatus characterized by that.   The sputtering apparatus according to claim 1, wherein the rotating cathode is supplied with pulsed power having a negative voltage applied when sputtering is substantially performed.   The sputtering apparatus according to claim 1, wherein the material supply unit includes a sputtering cathode.   The sputtering apparatus according to claim 3, wherein the sputtering cathode has a plurality of cathodes on which different types of target materials can be arranged.   The sputtering apparatus according to claim 3, wherein the sputtering cathode has a cylindrical shape whose peripheral surface rotates while facing the rotating cathode.   The sputtering apparatus according to claim 3, wherein the sputtering cathode is provided with a magnet on a side opposite to a surface on which the target material is provided.   The sputtering apparatus according to any one of claims 3 to 6, wherein the sputtering cathode is supplied with pulsed power having a negative voltage applied when sputtering is substantially performed.   The sputtering apparatus according to claim 7, wherein a phase of electric power applied to the rotating cathode is different from a phase of electric power applied to the sputtering cathode.   9. The material supply chamber is provided with an inert gas supply path through which an inert gas or a mixed gas of an inert gas and a reducing gas is supplied. A sputtering apparatus according to 1.   10. The gas shielding member according to claim 1, wherein an exhaust portion for exhausting gas in the chamber to the outside is provided on a side surface of the opening facing the rotating cathode. Sputtering equipment.   The reactive gas supply path is connected to a reactive gas supply source including at least one of oxygen, nitrogen, fluorine, ethylene, acetylene, benzene, tetrafluorocarbon, tetrafluoroethylene, and methane. The sputtering apparatus according to claim 1.   The sputtering apparatus according to claim 1, further comprising a promoting unit that promotes ionization or radicalization of the reactive gas.   The sputtering apparatus according to claim 1, wherein a magnet is provided on the inner peripheral side of the rotating cathode.   The sputtering apparatus according to claim 1, wherein the material supply unit includes a vapor deposition source for evaporating the thin film material.   The material supply means is supplied with a raw material containing at least one of a metal fluoride, a metal chloride, a metal hydride, and an organometallic compound, which is formed as a thin film material on the surface of the rotating cathode by vapor phase growth. The sputtering apparatus according to claim 1, further comprising a raw material supply path.