JP2012052149A - Sputtering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering device which shortens the downtime of the device and improves productivity.SOLUTION: The sputtering device 10 comprises: a chamber 12 which can maintain an atmosphere lower in pressure than the outside; a holding part 16 which holds a base material 14 in the chamber 12; a rotatable cylindrical rotating cathode 18 which is arranged so that its peripheral face opposes the base material 14 held by the holding part 16, and to which power for sputtering a target material on the surface is supplied; a metal material supply unit which can supply a metal material to the surface of the rotating cathode 18; and a blocking member 130 which regulates the movement of gas between a film-forming chamber 22 and a metal material supply chamber 24. The metal material supply unit has a raw-material supply passage 220 which can supply a raw material to be formed into a film as the target material on the surface of the rotating cathode 18 by chemical reaction.

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).

When manufacturing a thin film on a base material with such a sputtering apparatus, a metal plate having a thickness of, for example, 5 to 10 mm is used as a target. However, since the target is consumed by repeating the film formation, it is necessary to stop the apparatus at an appropriate timing and replace the consumed target with a new target. At that time, if the chamber held at a pressure close to a vacuum is opened and returned to atmospheric pressure, the thin film deposited on the inner wall of the chamber may become flakes and peel from the inner wall of the vacuum chamber. When exchanging the target, the metal protection plate installed on the inner wall of the chamber is usually removed from the apparatus and replaced. For this reason, for example, 6 to 12 hours are spent for these replacement operations, so that the stop time of the apparatus increases, and as a result, the productivity decreases.
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 a technique for directly forming a thin film from a gas or liquid metal material without using the above-described sputtering method, a so-called chemical vapor deposition method and a spray method are known. However, in these methods, for example, in order to form a high-density thin film, it is necessary to increase the temperature of the base material or the substrate. In addition, the spray method has a problem of poor controllability of film thickness and film properties.

  This invention is made | formed in view of such a condition, The objective is to provide the sputtering device which reduces the down time of an apparatus and improves productivity.

  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 rotatable rotating cathode provided with a peripheral surface facing the surface of the cylindrical rotating cathode to which power for sputtering the target material on the surface is supplied, and a thin film 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. The material supply means has a raw material supply path through which a raw material to be deposited as a target material on the surface of the rotating cathode by a chemical reaction can be supplied from outside.

  According to this aspect, even if the target material on the surface of the rotating cathode is consumed due to the film formation on the base material, the raw material is supplied in a gas or liquid state from the raw material supply path to the material supply chamber, and the raw material is newly rotated. Since the target is supplied to the surface of the cathode, film formation on the substrate by sputtering can be continued without stopping the apparatus. Here, the thin film material includes a material that can be formed as a thin film, for example, a pure metal, an alloy, a metal oxide, a metal nitride, a semiconductor material (silicon, germanium, a compound semiconductor), a carbon-based material, an organic polymer. Examples are materials (polyimide, polyamide, polytetrafluoroethylene) and the like.

  You may further provide the heating means which heats the surface of a rotating cathode so that it may become a temperature higher than room temperature. Thereby, decomposition | disassembly and reaction of a raw material are accelerated | stimulated and target material is formed in the surface of a rotating cathode at sufficient speed | rate.

  Plasma generation means for generating plasma inside the material supply chamber may be further provided. Thereby, decomposition | disassembly and reaction of a raw material are accelerated | stimulated and the film-forming temperature can be lowered | hung.

  The plasma generating means may be a capacitive coupling type. Here, capacitively coupled plasma (CCP) is generated, for example, by supplying high-frequency power between parallel plates. This promotes decomposition and reaction of the raw material even at a relatively low temperature.

  The plasma generating means may be an inductively coupled type. Here, inductively coupled plasma (IPC) is generated, for example, by flowing a high-frequency current through an induction coil. This promotes decomposition and reaction of the raw material even at a relatively low temperature.

  The raw material supply path supplies a raw material containing at least one of hydrocarbon, metal fluoride, metal chloride, metal hydride and organometallic compound, which is formed as a target material on the surface of the rotating cathode by vapor phase growth. May be.

  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 downtime of the apparatus can be reduced and the productivity 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 raw material supply path 220, a heater 222 for heating the raw material gas supplied from the raw material supply path 220, a film forming chamber 22 provided with the holding unit 16, and a metal material supply chamber 24 provided with the raw material supply path 220. A gas shielding member 130 having a rectangular opening 28 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 the gas between Equipped with a. The film forming chamber 22 is provided with an inert gas supply path 46 through which an inert gas such as argon is supplied.

  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 supplied by a source gas supplied from a source supply path 220 to the exposed surface of the sleeve 34 made of aluminum or SUS. It may be formed and used as the rotating cathode 18. 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.

  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.

  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 fluorides, metal chlorides, metal hydrides, organometallic compounds, and the like are used. Specific examples include titanium chloride and molybdenum hexafluoride. 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, 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 substrate is formed in the film forming chamber 22 separated by the gas shielding member 130. By simply exchanging 14, continuous film formation on a plurality of substrates can be performed. Further, it is possible to suppress a gas serving as a raw material at the time of vapor phase growth from flowing out to the film forming chamber 22 from the metal material supply chamber 24 provided with the raw material supply path 220.

  In other words, even if the target 38 on the surface of the rotating cathode 18 is consumed due to film formation on the base material 14, the raw material is supplied from the raw material supply path 220 to the metal material supply chamber 24 in a gas or liquid state, and the raw material is Since a new target is supplied to the surface of the rotating cathode 18, film formation on the substrate 14 by sputtering can be continued without stopping the apparatus.

  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, the reactive gas, and the raw material 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, for example, by making the pressure in the film formation chamber 22 slightly higher than the pressure in the metal material supply chamber 24. The source gas in the supply chamber 24 is suppressed from flowing into the film forming chamber 22.

  As described above, the sputtering apparatus 10 can continuously supply a material such as a metal or a metal compound to the surface of the target 38, in addition to the rotating cathode 18, the raw material supply path 220 as a metal material supply source. It has. Further, the gas shielding member 130 suppresses mixing of the inert gas introduced into the film forming chamber 22 and the raw material gas in the metal material supply chamber 24. Therefore, the metal can be supplied from the raw material supply path 220 to the rotating cathode 18. By rotating the rotating cathode 18 constantly or intermittently, a metal thin film can be formed on the target 38 of the rotating cathode 18 at all times. Therefore, the downtime of the apparatus due to the replacement of the target is suppressed, and the productivity is improved. can do.

(Titanium metal thin film deposition method)
A method for forming a titanium metal thin film on a substrate using the sputtering apparatus 10 will be described in detail. First, titanium chloride vaporized by a bubbling device using argon gas as a carrier is introduced into the metal material supply chamber 24 from the raw material supply path 220. The surface of the rotating cathode 18 rotating at 3 to 30 rpm is heated to about 350 ° C. at which titanium chloride is sufficiently decomposed by the infrared heater 222. Thereby, metal titanium is deposited on the surface of the rotating cathode 18.

  On the other hand, an argon gas that functions as a discharge gas is introduced from the inert gas supply path 46 into the film forming chamber 22 in which the rotating cathode 18 is provided. The pressure of the argon gas at that time is 0.4 Pa. Next, with the rotating cathode 18 having a length of 500 mm rotated, DC power of about 3 kW is supplied to the rotating cathode 18 to cause discharge in the region including the magnetic circuit on the substrate 14 side. A titanium thin film is formed.

(Silicon metal thin film deposition method)
A method for forming a silicon metal thin film on the substrate using the sputtering apparatus 10 will be described in detail. First, silane (SiH ₄ ) is introduced from the raw material supply path 220 into the metal material supply chamber 24 using argon gas as a carrier. At that time, phosphine (PH ₃ ) gas is mixed as a dopant gas. The pressure of silane is about 1.0 Pa, and the partial pressure of phosphine is about 0.03 Pa. Then, the surface of the rotating cathode 18 rotating at 3 to 30 rpm by the infrared heater 222 is heated to about 300 ° C. where silane is sufficiently decomposed. Thereby, metallic silicon is deposited on the surface of the rotating cathode 18.

  On the other hand, argon gas is introduced from the inert gas supply path 46 into the film forming chamber 22 where the rotary cathode 18 is provided. The pressure of the mixed gas at that time is 1.0 Pa. Next, with the rotating cathode 18 having a length of 500 mm being rotated, about 3 kW of DC power having a reverse-biased pulse of 100 kHz is supplied to the rotating cathode 18 to discharge the substrate 14 side to the region including the magnetic circuit. And a phosphorus-doped silicon thin film is formed on the substrate 14.

(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 a major difference from the first embodiment in that a plasma generating means for promoting the decomposition of the raw material is provided in the metal material supply chamber 24. 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 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 a 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. The gas shielding member 130 in which the opening 28 is formed and the plasma generating means 250 for generating plasma inside the metal material supply chamber 24 are provided. The plasma generating means 250 according to the present embodiment is an inductively coupled device having an induction coil 252 for passing a high-frequency current. For example, capacitive coupling that generates plasma by supplying high-frequency power between parallel plates is used. Type plasma apparatus.

(Titanium metal thin film deposition method)
A method of forming a titanium metal thin film on the substrate using the sputtering apparatus 110 in which the plasma generating means 250 is provided in the metal material supply chamber 24 will be described in detail. First, titanium chloride vaporized by a bubbling device using argon gas as a carrier is introduced into the metal material supply chamber 24 from the raw material supply path 220. The surface of the rotating cathode 18 rotating at 3 to 30 rpm by the infrared heater 222 is heated to about 250 ° C., and 500 W of high frequency power is supplied to the induction coil 252 of the plasma generating means 250. Thus, titanium chloride is sufficiently decomposed in a lower temperature environment, and metallic titanium is deposited on the surface of the rotating cathode 18.

  On the other hand, argon gas is introduced from the inert gas supply path 46 into the film forming chamber 22 where the rotary cathode 18 is provided. The pressure of the argon gas at that time is 0.4 Pa. Next, with the rotating cathode 18 having a length of 500 mm rotated, DC power of about 3 kW is supplied to the rotating cathode 18 to cause discharge in the region including the magnetic circuit on the substrate 14 side. A titanium thin film is formed.

(Third embodiment)
In the present embodiment, a method for forming a titanium dioxide thin film on a substrate using the sputtering apparatus 10 according to the first embodiment will be described in detail. First, titanium chloride vaporized by a bubbling device using argon gas as a carrier is introduced into the metal material supply chamber 24 from the raw material supply path 220. The surface of the rotating cathode 18 rotating at 3 to 30 rpm is heated to about 350 ° C. at which titanium chloride is sufficiently decomposed by the infrared heater 222. Thereby, metal titanium is deposited on the surface of the rotating cathode 18.

  On the other hand, argon gas and oxygen gas as a reactive gas are introduced from the inert gas supply path 46 into the film forming chamber 22 where the rotating cathode 18 is provided. At that time, the pressure of argon gas is 0.4 Pa and the partial pressure of oxygen gas is 0.08 Pa. Next, DC power of about 3 kW is supplied in a state where the rotating cathode 18 having a length of 500 mm is rotated, discharge is generated in the region including the magnetic circuit on the base material 14 side, and a titanium dioxide thin film is formed on the base material 14. To do.

(Fourth embodiment)
In the present embodiment, a method for forming a silicon thin film for a solar cell by using the sputtering apparatus according to each of the embodiments as described above will be described in detail.

Conventionally, a silicon layer of a thin-film silicon solar cell has been produced mainly by a plasma chemical vapor deposition method using silane (SiH ₄ ) gas as a raw material. In the plasma chemical vapor deposition method, silane gas is decomposed into a form such as SiH ₃ or SiH ₂ in the plasma, and the reaction is promoted on the substrate by increasing its activity to form a thin film. Although it was possible to obtain a microcrystalline thin film capable of battery operation even at a substrate temperature of about 100 ° C., it is necessary to increase the substrate temperature to 400 ° C. to 500 ° C. in order to obtain a more efficient battery cell. there were. At the same time, in order to improve the quality of the thin film, it was necessary to suppress the production of so-called higher order by-products and to remove them quickly from the film forming chamber.

  When a silicon layer is formed by using the sputtering method, it is naturally expected that the substrate temperature is lowered as a characteristic of the sputtering method, the film thickness and characteristics are made uniform on a large area substrate, and the process reproducibility is improved. Further, the problem of deterioration of the thin film quality due to higher by-products is also suppressed. However, the sputtering method is difficult due to the difficulty in forming a large area target and the generation of defects in the silicon layer due to the scattering of small silicon pieces from the silicon target during sputtering as foreign matter due to stress and the like, and adhering to the substrate. The silicon layer formation by has not been put into practical use industrially.

  Therefore, a method for producing thin-film silicon by using the above-described sputtering apparatus that can take advantage of the sputtering method and suppress downtime due to target replacement will be described. In the sputtering apparatus 10 shown in FIG. 1, while supplying a silicon raw material as gas from the raw material supply path 220, this is once made into a solid target on the surface of the rotary cathode 18, and this is sputtered to form a final silicon thin film on the substrate. obtain. Silicon deposited on the surface of the rotating cathode 18 used as a target is a thin layer, and does not scatter as a foreign substance due to thermal stress or stress induced during sputtering, and does not form a defect in the layer on the substrate.

  In this way, the silicon layer is formed by the sputtering method, so that the sputtered particles having a large momentum can take advantage of the original characteristics of the sputtering method in which a high-density thin film is formed on a substrate having a low temperature. Become. This is a significant advantage of thin film formation by sputtering compared to the absence of physical momentum contribution to the high density of the thin film in plasma enhanced chemical vapor deposition. Further, higher-order by-products generated from silane are exhausted without flowing into the thin film forming chamber, and do not affect the quality of the thin film. Further, the ability to continuously supply the thin film raw material, which is a feature of the present invention, brings about the advantage of reducing the apparatus downtime for maintenance in production.

Specifically, silane SiH ₄ is supplied to the metal material supply chamber 24 using H ₂ as a carrier gas. A predetermined amount of diborane (B ₂ H ₆ ) is simultaneously supplied as a dopant. And the temperature of the rotary cathode 18 is heated to about 200 degreeC with the heater 222, and silicon is deposited on the surface. A direct current or pulse power is supplied to the rotating cathode 18 to generate a discharge on the thin film forming chamber side, and a silicon thin film is formed on the substrate by sputtering. The substrate temperature is 200 ° C. The substrate temperature may be further increased as necessary. The generated silicon layer was microcrystalline, and no defects were found due to scattering of silicon pieces.

  In this way, the present invention realizes an unprecedented sputtering apparatus by combining the characteristics of high-speed and dense film formation by sputtering and the ability to continuously supply raw materials such as CVD and spraying. To do. The supplied raw material is continuously or intermittently deposited as a metal on the target by a thermal decomposition reaction or a thermal decomposition reaction assisted by plasma.

  The thin film formed on the base material or the substrate by sputtering the target has a feature that the energy of the material to be the thin film itself is high, so the film density can be increased without increasing the temperature of the base material or the substrate. It is possible to form a thin film having a high adhesion force or a large adhesion force to the substrate or substrate of the film. As a result, it is possible to form a film at a temperature lower than the substrate temperature required in the conventional chemical vapor deposition method or spray method.

  In addition, a reduction in the downtime of the sputtering apparatus for target replacement is achieved. In addition, since the thin film deposited on the substrate is formed by the sputtering method, it is possible to deposit a thin film having excellent mechanical, optical, or electrical properties, which is a feature of the sputtering method, and also to increase the area. It becomes easy.

  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.

  The present invention can be used in various fields such as electrical / electronic equipment, electronic devices, vehicles, architecture, and ornaments. For example, in the production of a plastic film coated with a metal used for electrical equipment, it is possible to form a metal thin film continuously while keeping the plastic film as a base material at a low temperature. In forming a thin film on a vehicle or architectural plate glass, for example, a stainless steel thin film can be continuously formed. The present invention is appropriately used in a process for forming a thin film continuously or intermittently while taking advantage of the characteristics of these sputtering methods.

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.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Sputtering device, 12 Chamber, 14 Base material, 16 Holding part, 18 Rotating cathode, 22 Deposition room, 24 Metal material supply room, 26 Gap, 28 Opening part, 34 Sleeve, 36 Magnet, 38 Target, 46 Inert gas Supply path, 50 discharge port, 110 sputtering apparatus, 130 gas shielding member, 210 sputtering apparatus, 220 raw material supply path, 222 heater, 250 plasma generating means, 252 induction coil.

Claims (6)

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 thin film 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 formed with an opening to be disposed;
The material supply means has a raw material supply path capable of supplying a raw material formed as a target material on the surface of the rotating cathode by a chemical reaction from the outside.
A sputtering apparatus characterized by that.   The sputtering apparatus according to claim 1, further comprising a heating unit that heats the surface of the rotating cathode so as to have a temperature higher than room temperature.   The sputtering apparatus according to claim 1, further comprising plasma generating means for generating plasma inside the material supply chamber.   The sputtering apparatus according to claim 3, wherein the plasma generation unit is a capacitive coupling type.   The sputtering apparatus according to claim 3, wherein the plasma generating unit is an inductively coupled type.   The raw material supply path is formed of a raw material containing at least one of hydrocarbon, metal fluoride, metal chloride, metal hydride and organometallic compound, which is formed as a target material on the surface of the rotating cathode by vapor phase growth. The sputtering apparatus according to claim 1, wherein the sputtering apparatus is supplied.

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