JP2018204056A - Sputtering device and method - Google Patents

Abstract

To provide a sputtering device and a method capable of providing inexpensively a high-quality thin film by a simple device constitution.SOLUTION: In a reactive sputtering method for forming a thin film by reacting a target material 7 with gas, a thin film is formed by laminating repeatedly a first kind of thin film layer 32 of the thin film formed by pulsing a waveform of a current from a DC power supply 20 for generating plasma, and applying it to the target material, and a second kind of thin film layer 31 of the thin film formed by applying the waveform of the current from the DC power supply to the target material as a continuous wave.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique of laminating two or more types of films having different physical properties among sputtering apparatuses and methods for forming a thin film on a substrate such as a semiconductor wafer or glass.

Relative to thin film optical devices such as optical filters used in wavelength demultiplexers for optical communications, antireflection films formed on the lens surface of digital cameras, or dichroic mirrors that separate RGB light by projectors In addition, it has a multi-layered structure of a thin film layer having a high refractive index and a thin film layer having a low refractive index. The number of layers is about 5 to several tens depending on the required accuracy. In many cases, the high refractive index material and the low refractive index material are composed of different metal oxides. For example, Nb ₂ O ₅ , Ta ₂ O ₅ , or TiO ₂ is used as the high refractive index material, and SiO ₂ or MgF ₂ is used as the low refractive index material. In order to form a laminated film by sputtering using these materials, at least two targets are required. Furthermore, when the target material is finally produced with a necessary oxide as a laminated film, it becomes a ceramic sintered target, which is relatively expensive and may be difficult to handle. Further, when the oxide target is sputtered in an atmosphere containing only argon gas, a slight oxygen deficiency occurs. In the case of SiO _2, a SiOx (x <2). In order to make up for this oxygen deficiency, an oxygen gas of about 3% is generally added to the argon gas. In this case, however, a production problem occurs in that the film formation rate decreases. As described above, the facilities must be complicated, and the occurrence of impurity contamination (contamination) due to the mutual materials in the apparatus cannot be denied.

  Conventionally, there is a carousel type sputtering apparatus as one of sputtering apparatuses aiming at the formation of such a laminated thin film (for example, see Patent Document 1).

  A conventional multilayer thin film sputtering apparatus and method will be described with reference to FIGS.

FIG. 5 shows a plan view of a conventional laminated thin film sputtering apparatus. A unit of a target 7 a (for example, Si) made of a constituent material of a low refractive index material (for example, SiO ₂ ) and a backing plate 8 a for attaching the target to one surface of a rectangular vacuum chamber 101 that can be evacuated, and a vacuum A unit of a target 7b (for example, Nb) made of a constituent material of a high refractive index material (for example, Nb ₂ O ₅ ) and a backing plate 8b for mounting the target 7b is installed on the opposing surface of the chamber 101. Oxygen plasma is generated on the surface of the vacuum chamber 101 where the two targets 7a and 7b are not attached to oxidize the aforementioned two materials (Si and Nb) to become SiO ₂ and Nb ₂ O ₅ , respectively. A unit of an inductively coupled plasma generator 51 and a high frequency discharge chamber 52 is provided.

  In order to suppress the interaction between the respective film forming materials or oxygen plasma as much as possible, the shielding plates 56a, 56b, and 56c are installed so as to isolate the respective units. Further, DC power sources 30a and 30b for sputtering are connected to the backing plates 8a and 8b, respectively. The gas for generating plasma is supplied to the inside of the shielding plates 56a, 56b, and 56c by the gas supply units 4a, 4b, and 4c via a mass flow controller (not shown).

  A high frequency coil 53 for generating plasma is wound around the high frequency discharge chamber 52. High frequency application to the high frequency coil 53 is performed by a high frequency power supply 55 and a matching box 54.

At the center of the vacuum chamber 101, there is a substantially cylindrical substrate holder 105. Although it is described as a cylinder, in practice, a regular polygonal structure is often used because the substrate is attached to the side surface. The substrate holder 105 has a structure that rotates as indicated by an arrow in FIG. 5. Next, a film forming method will be described with reference to FIGS. 5 and 6.

  FIG. 6 shows a flowchart of film formation. This will be described with reference to FIG.

First, the substrate is loaded. In this case, the substrate to be deposited is attached to the side surface of the substrate holder 105. After the substrate is attached to the substrate holder 105, the vacuum chamber 101 is evacuated. Generally, roughing is performed with an oil rotary pump, and then high vacuum evacuation is performed to a level of 10 ⁻⁵ Pa with a turbo pump and a cryopanel. When the ultimate vacuum level set in advance is reached, first, a gas for sputtering deposition of the first layer, for example, the low refractive index material SiO ₂ is introduced, and the pressure is adjusted. In this case, argon gas is supplied near the Si target using the gas supply unit 4a of FIG. 5, and oxygen gas is supplied to the high-frequency discharge chamber 52 using the gas supply unit 4c. Further, the pressure in the vacuum chamber 101 is adjusted to a predetermined value by a pressure adjusting mechanism (not shown). At the same time, the substrate holder 105 is rotated.

  Thereafter, in order to generate plasma, the DC power supply 30a and the high frequency power supply 55 are activated, and predetermined power is applied to the backing plate 8a and the high frequency coil 53, respectively. From this point, measurement of the film formation time is started.

At this time, an extremely thin Si thin film is formed on the substrate attached to the substrate holder 105 when passing in front of the target 7 a, and then oxygen is added to the aforementioned Si when passing in front of the high-frequency discharge chamber 52. Components generated by the plasma act and are converted to SiO ₂ . By repeating this, a SiO ₂ thin film is formed on the substrate.

  When the predetermined film formation time ends, the DC power supply 30a and the high frequency power supply 55 are disconnected and the film formation is stopped. Next, gas supply and pressure adjustment by the gas supply units 4a and 4c are also stopped, and a vacuum exhaust state is set.

Next, the second layer, for example, a high refractive index material Nb ₂ O ₅ is formed by sputtering. Also in this case, film formation was started in the same procedure as in the case of the first layer, and an extremely thin Nb thin film was formed when it passed in front of the target 7b, and then passed in front of the high-frequency discharge chamber 52. At this time, the component generated by the oxygen plasma acts on the aforementioned Nb and is converted to Nb ₂ O ₅ . By repeating this, an Nb ₂ O ₅ thin film is formed on the substrate.

  A desired laminated thin film is formed by repeating the lamination of the above two layers. When the final layer is completed, nitrogen gas or the like is introduced into the vacuum chamber 101 to open the atmosphere, and the film-formed substrate is taken out.

Japanese Patent Laid-Open No. 8-176721

  However, the above-described conventional methods have problems in terms of equipment cost, productivity, and quality. First, regarding the equipment cost, in the conventional method, it is necessary to prepare targets as many as the number of materials to be deposited, and the volume of the vacuum chamber is inevitably increased in consideration of the locations where these targets are attached. In general, a pump for vacuum evacuation, a mechanism such as a valve for pressure adjustment, and a power source occupy most of the cost of a thin film forming apparatus such as a sputtering apparatus. If the volume of the vacuum chamber increases, a larger pump and a larger pumping speed will be selected, and the pressure adjustment valve will basically match the size of the pump. This will increase costs. In addition, as the number of targets increases, the cost of the power source also increases, and the overall equipment cost increases.

  Next, with respect to productivity, as described with reference to FIG. 6, the conventional method requires switching time such as gas switching and pressure adjustment, and the time required increases as the total number of layers increases. Further, the gas flowing during the time until the pressure stabilizes is wasted because it is exhausted as it is without contributing to production.

  Finally, quality. As described with reference to FIG. 5, each of the targets 7a and 7b or the high-frequency discharge chamber 52 is partitioned by the shielding plates 56a, 56b, and 56c, but is constant between the substrate holder 105 that is a rotating body. It is necessary to provide a clearance, and the mutual influence cannot be denied. In particular, when the oxygen plasma component reaches an undischarged target from the high-frequency discharge chamber 52, there is a possibility that the target surface is oxidized, and then the composition or refractive index of the thin film formed using the target is changed. May affect quality.

  The present invention solves the problems of the conventional methods as described above, and an object thereof is to provide a sputtering apparatus and method capable of providing a high-quality thin film at a low cost with a simple apparatus configuration. It is.

A sputtering apparatus according to one aspect of the present invention includes:
It is a reactive sputtering method in which a target material and a gas are reacted to form a thin film,
When generating plasma, the waveform of the current from the DC power source is pulsed and applied to the target material, and the first type thin film layer of the thin film is formed, and the waveform of the current from the DC power source is a continuous wave. The thin film is formed by repeatedly laminating the second type thin film layer of the thin film formed by applying to the target material.

A sputtering apparatus according to another aspect of the present invention includes:
A direct current power source that applies direct current when generating plasma when performing reactive sputtering to react a target material and a gas to form a thin film;
A pulsing unit capable of pulsing a waveform of a current from the DC power source and applying it to the target material;
Controls the reaction rate between the target material and the gas during sputtering film formation, and turns on / off the operation of the pulsing unit to form two or more types of thin film layers having different ratios of gas-derived elements present in the thin film A control unit for controlling.

  According to the aspect of the present invention, the current flowing from the DC power source to the target material can be pulsed, and the waveform of the current applied to the target material is changed between the pulse waveform and the continuous waveform by controlling on / off of the pulsing. ing. By configuring in this way, even with only one type of target, for example, it is possible to form two types of thin film layers having different refractive indexes, thereby simplifying the configuration of the apparatus and reducing the equipment cost. As a result, products manufactured with such an apparatus can be provided at a lower price. Further, at that time, switching of gas and pressure is unnecessary, and mutual influence with other materials does not occur, so that high productivity and high quality can be realized at the same time.

Schematic cross-sectional view of the sputtering apparatus according to Embodiment 1 of the present invention The flowchart which shows the sputtering method of Embodiment 1 in this invention. Schematic sectional view of the laminated thin film formed in the first embodiment of the present invention Schematic sectional view of the laminated thin film formed in the second embodiment of the present invention A schematic plan view of a conventional sputtering apparatus for laminated thin films Flow chart showing conventional sputtering method for laminated thin film

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, the configuration of the sputtering apparatus according to the first embodiment will be described with reference mainly to FIG. The same applies to other embodiments.

  FIG. 1 is a schematic cross-sectional view of the sputtering apparatus according to the first embodiment of the present invention. The sputtering apparatus includes a vacuum chamber 1, a vacuum pump 2, a gas supply source 4, a backing plate 8, a DC power source 20, a pulse unit 21, a power source / pulse controller 22 that functions as an example of a control unit, And a substrate holder 5.

  The vacuum chamber 1 can be depressurized to a vacuum state by evacuating with a vacuum pump 2 connected via a gate valve 3.

  The gas supply source 4 can supply a gas necessary for sputtering to the vacuum chamber 1 at a constant speed. As the gas supplied from the gas supply source 4, for example, a gas having reactivity with a target material such as nitrogen or oxygen, or a mixed gas of a reactive gas and a rare gas such as argon can be selected.

  The gate valve 3 can control the degree of vacuum in the vacuum chamber 1 to a desired gas pressure by changing its open / close ratio.

  In FIG. 1, a target material 7 is disposed in the upper part of the vacuum chamber 1. The target material 7 is an arbitrary sputter material, but is an inorganic material such as a metal material or a semiconductor material. In the case of this Embodiment 1, it is Si as an example.

  The backing plate 8 is disposed in the upper part of the vacuum chamber 1 and supports the target material 7 so as to face a substrate holder 5 described later.

  The DC power source 20 is electrically connected to the target material 7 via the pulsing unit 21 and the backing plate 8, and can apply a voltage to the target material 7.

  The pulsing unit 21 accumulates a direct current generated by the direct current power source 20 in a built-in capacitor or the like, and can be turned on or off by a built-in semiconductor switching element or the like to make a pulse.

  The power source / pulse controller 22 reads the refractive index level of the layer to be deposited from the pre-input conditions, is connected to the read information, the DC power source 20 and the pulse unit 21, and the pre-set set value Based on the above, the power value of the DC power supply 20 and the ON time and OFF time of the pulse instructed to the pulsing unit 21 are controlled.

  The magnet 9 and the yoke 10 are disposed on the back surface of the backing plate 8 in the upper part of the vacuum chamber 1, and can generate a magnetic field on the surface of the target material 7.

  In FIG. 1, a substrate holder 5 that supports a substrate 6 is disposed in a lower portion of the vacuum chamber 1. The substrate holder 5 is disposed below the substrate 6 and supports the substrate 6 so that the surface of the substrate 6 faces the surface of the target material 7 supported by the backing plate 8.

  Here, an important technique constituting the sputtering apparatus of the present embodiment will be described.

  In the reactive sputtering method, the present inventors selectively use a conventional continuous wave and a pulse wave that concentrates and applies power in a short time of about 10 microseconds as a current to be applied for plasma generation. It has been found that the physical properties of the produced thin film can be controlled even under the same gas flow rate and pressure conditions. In the process of forming an oxynitride film using a metal or semiconductor target, high power is instantaneously applied by applying power for generating plasma in a short time of about 5 microseconds. For example, compared to direct current sputtering using a 100 W continuous wave, when trying to consume the same power concentrated in only 1 / 100th of the pulse period, a power of 10000 W, which is 100 times greater, is applied instantaneously. Will be. It is said that the dissociation energy is relatively high due to the momentary application of high power, and the dissociation of nitrogen gas, which is difficult to dissociate in the past, is promoted, and highly reactive atomic nitrogen or nitrogen in a radical state is generated. Occur. Thereby, nitriding of the thin film is promoted, and as a result, a thin film having a high nitrogen concentration ratio can be obtained as compared with a thin film obtained by direct current sputtering using a continuous wave.

  The examination results in the first embodiment will be briefly described below.

Si was used as a target material, nitrogen gas and oxygen gas were used as gases, and the flow rate ratio of oxygen gas to the total gas flow rate was 2%. The refractive indexes of the thin films prepared by continuous wave direct current sputtering and pulse sputtering were compared. The pulse conditions were a frequency of 10 kHz and a duty ratio for applying power was 5%. Here, although the refractive index of the thin film produced by normal continuous wave direct current sputtering is 1.54, the refractive index of the thin film produced by pulse sputtering according to the present embodiment is 1.75. It was. The refractive index of the bulk of SiO ₂ is about 1.45, Si ₃ N ₄ is about 2.02, and 1.75 which is the refractive index of the thin film of the present embodiment shows a value between them. Therefore, it is considered that the refractive index difference is due to the difference in the nitrogen ratio of the SiON film.

  Here, with regard to the frequency of the pulse of this pulse sputtering, under the condition of the low frequency side, for example, less than 1 kHz, in the study by the inventors, the plasma discharge becomes extremely unstable, and when the high frequency side exceeds, for example, 100 kHz, The period was about 10 macroseconds, and it was found that the duty ratio could not be lowered to a desired value due to limitations of the power supply device. For this reason, the frequency is considered to be 1 kHz or more and 100 kHz or less.

  The ratio of the time for applying power in one cycle is preferably a short time in order to achieve the above-mentioned purpose of applying large power instantaneously. Is in the middle of rising, and there is insufficient time to reach the set power. Further, from the vicinity of over 30%, the atomic nitrogen or radical nitrogen formed by the dissociation of the aforementioned nitrogen gas decreases, and when it becomes about 50%, it becomes the same state as normal DC sputtering. Therefore, it is considered that 0.1% or more and 30% or less is appropriate for the ratio of the time for applying power in one cycle.

  In the case of SiON, which is a silicon oxynitride film, it is known that the density or refractive index of the film or the characteristics such as the residual stress of the film varies depending on the nitrogen ratio. In general, it is known that as the nitrogen ratio increases, the density and refractive index of the film and the residual stress tend to increase. In other words, the density increases as the nitrogen ratio increases, making it difficult for moisture or gas to pass through, improving the performance as a protective film, while increasing the residual stress. It can also cause peeling due to warpage or stress. However, it is epoch-making that the physical properties of the thin film can be controlled only by the method of applying power, and the productivity can be reduced by reducing the cost by simplifying the equipment or by reducing the time required for process switching such as gas or pressure conditions. Industrial value such as improvement is extremely high.

  Next, the operation of the sputtering apparatus according to the first embodiment will be described, and the sputtering method according to the first embodiment will be described with reference to FIG. The same applies to other embodiments. Further, an antireflection film will be described as an example of a device to be manufactured. As shown in FIG. 3, the antireflection film is a device in which thin films 32 having a relatively low refractive index and thin films 31 having a relatively high refractive index are alternately stacked on a glass substrate 33. . The thin film 31 having a relatively high refractive index is an example of the first type of thin film layer, and is, for example, SiOxNy (where x <y). The thin film 32 having a relatively low refractive index is an example of the second type thin film layer of the thin film, and is, for example, SiOxNy (where x> y). The thin film 31 having a relatively high refractive index means having a refractive index higher than that of the thin film 32. Conversely, the thin film 32 having a relatively low refractive index means having a refractive index lower than that of the thin film 31.

  First, the substrate is loaded (step S1). A substrate 6 to be deposited, for example, a glass substrate 33 is placed at the position of the substrate 6 in FIG. The substrate 6 may be installed directly by hand with the vacuum chamber 1 opened to the atmosphere, or may be installed by a machine using a robot arm or the like from the load lock chamber without opening to the atmosphere.

  Subsequently, the vacuum pump 2 is operated to reduce the pressure so that the inside of the vacuum chamber 1 is in a vacuum state, and after reaching a predetermined degree of vacuum (step S2), gas is introduced from the gas supply source 4, The opening degree of the gate valve 3 is adjusted so as to be the gas pressure (step S3).

  When the gas flow rate and pressure are stable, power is applied, plasma is generated, and film formation is started, but switching between the pulse wave and continuous wave is performed during layer switching until the final layer is stacked. The power application is not interrupted. The same applies to gas supply and pressure adjustment.

  First, the refractive index of the first layer is read by the power supply / pulse controller 22 from previously input conditions (step S4). If the layer 31 has a high refractive index, the power generation condition and the pulse generation condition are instructed to the DC power source 20 and the pulsing unit 21, respectively, and the film formation starts simultaneously with the application of power (step S5). In the case of the low refractive index layer 32, the power condition is instructed only to the DC power source 20, and the film formation starts simultaneously with the application of power (step S6). The film thickness to be formed is basically managed by the power source / pulse controller 22 with time (steps S7 and S8). Immediately after the predetermined film formation time, the condition of the next layer is read by the power supply / pulse controller 22 and the conditions of the DC power supply 20 and the pulse unit 21 are switched (steps S9 and S4). That is, to change from the high refractive index condition to the low refractive index condition, the pulsing unit 21 is stopped, and vice versa. Although the time required for this switching operation depends on the responsiveness of the control system for controlling the sputtering apparatus, it is usually 0.1 seconds or less, which is sufficiently shorter than the film formation time and is given to the film thickness. It can be said that there is almost no influence. As described above, when film formation up to the final layer is completed only by switching the pulse conditions (step S9), the operations of the DC power source 20, the pulse unit 21, and the power source / pulse controller 22 are stopped, and the gas supply and pressure adjustment are performed. Is also stopped and the film formation is completed (step S10). The substrate after film formation is taken out, and the series of operations ends (step S10).

  According to the above, in sputtering, a thin film laminated structure having a relatively low-refractive index layer 32 and a relatively high-refractive index layer 31 can be formed with only one target material 7 by only switching the pulse on and off. Since it can be manufactured, the device configuration can be simplified. Further, there is no time that does not contribute to the formation of a thin film between the relatively low refractive index layer 32 and the relatively high refractive index layer 31, for example, there is no gas switching or pressure stabilization waiting time. Can be improved.

(Embodiment 2)
Next, the sputtering method of Embodiment 2 is demonstrated using FIG.

  In the second embodiment, formation of a protective film 45 of a device in which a functional element 44 such as a resistor or a semiconductor is formed on a silicon substrate 43 will be described. The function of the protective film 45 of the electronic device is to prevent the performance fluctuation or deterioration of the electronic device due to the environment. In many cases, it is required to prevent oxidation of a metal often used for the functional element 44 or the electrode 46, and to prevent contact or permeation with moisture or oxygen (air) in the air.

  As the protective film 45, a SiN film is a film having a particularly high performance for preventing moisture permeation. The performance as the protective film 45 is proportional to its density and film thickness. That is, the protective performance can be ensured by forming a thick film such as SiNx thick. However, SiNx is known to have a drawback that the residual stress of the film is relatively large due to its high density. If the stress is high, the substrate 43 and the substrate 43 may be warped, causing a transport error in the manufacturing process. Moreover, it causes film peeling from the end of the film where stress is concentrated.

  Therefore, in the second embodiment, by taking advantage of the present invention, the protection performance and the stress relaxation are layered by alternately laminating the layer 41 having a high protection performance and the layer 42 for stress relaxation although the protection performance is slightly inferior. It was decided to satisfy both performance and performance. As described in the first embodiment, the first layer is the protective layer 41, the pulsing unit 21 is operated to form the SiON film having a relatively high nitrogen ratio, the second layer is the stress relaxation layer 42, and A SiON film having a relatively low nitrogen ratio is formed by wave direct current sputtering. By alternately repeating the stacking of the two layers 41 and 42 as described above, the stress-relieving protective film 45 can be formed. The layer 41 with high protection performance is, for example, SiOxNy (where x <y). Although the protective performance is slightly inferior, the layer 42 for stress relaxation is, for example, SiOxNy (where x> y).

  According to the second embodiment, such a laminated structure can be continuously formed with only one target material 7. Since there is no timing between the protective layer 41 and the stress relaxation layer 42 when the film surface is not formed and the surface of the thin film is exposed to the gas, there is no gas adsorption or reaction that deteriorates the adhesion at the interface. And a highly reliable protective film 45 can be formed.

  According to the first and second embodiments, the pulsing unit 21 capable of pulsing the current flowing from the DC power source 20 to the target material 7 is provided, and the current applied to the target material 7 by controlling the pulsing unit 21 on and off. The waveform is changed between a pulse waveform and a continuous waveform. By configuring in this way, even with only one type of target, for example, it is possible to form two types of thin film layers having different refractive indexes, thereby simplifying the configuration of the apparatus and reducing the equipment cost. As a result, products manufactured with such an apparatus can be provided at a lower price. Further, at that time, switching of gas and pressure is unnecessary, and mutual influence with other materials does not occur, so that high productivity and high quality can be realized at the same time.

  In addition, this invention is not limited to the said embodiment, It can implement in another various aspect. For example, the two types of thin film layers 31, 32, 41, and 42 to be stacked include at least one material of Si, Nb, Ta, and Ti, and may be any oxynitride of the material.

  It is to be noted that, by appropriately combining any of the various embodiments or modifications, the effects possessed by them can be produced. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features in different embodiments or examples are also possible.

  The sputtering apparatus and the sputtering method according to the aspect of the present invention can continuously and efficiently produce a laminated film composed of two types of thin films with an apparatus having a simple configuration, and can be used for optical filters or thin film electronic devices composed of laminated thin films. It is useful as an apparatus and method for manufacturing a protective film and the like at low cost with an apparatus having a simple structure.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Pump 3 Gate valve 4 Gas supply source 5 Substrate holder 6 Substrate 7 Target material 8 Backing plate 9 Magnet 10 Yoke 20 DC power source 21 Pulse unit 22 Power source / pulse controller 31 Thin film 32 having a relatively high refractive index Thin film 33 having a relatively low refractive index Glass substrate 41 Protective layer 42 Stress relaxation layer 43 Silicon substrate 44 Functional element 45 Protective film 46 Electrode

Claims (5)

It is a reactive sputtering method in which a target material and a gas are reacted to form a thin film,
When generating plasma, the waveform of the current from the DC power source is pulsed and applied to the target material, and the first type thin film layer of the thin film is formed, and the waveform of the current from the DC power source is a continuous wave. As a sputtering method, the second thin film layer of the thin film formed by applying to the target material is repeatedly laminated to form the thin film.   The waveform of the current to be applied in the form of a pulse is a frequency of 1 kHz or more and 100 kHz or less, and a ratio of time for applying power in one cycle is 0.1% or more and 30% or less. Sputtering method.   The two types of thin film layers to be stacked include at least one material of Si, Nb, Ta, and Ti, and are oxynitrides of the materials when the layers are repeatedly stacked. A sputtering method according to 1.   4. Any one of claims 1 to 3, wherein the thin film layer to be laminated is configured by alternately forming a thin film layer having a relatively high refractive index and a thin film layer having a relatively low refractive index when the layers are repeatedly laminated. The sputtering method as described in any one. A direct current power source that applies direct current when generating plasma when performing reactive sputtering to react a target material and a gas to form a thin film;
A pulsing unit capable of pulsing a waveform of a current from the DC power source and applying it to the target material;
Controls the reaction rate between the target material and the gas during sputtering film formation, and turns on / off the operation of the pulsing unit to form two or more types of thin film layers having different ratios of gas-derived elements present in the thin film A sputtering apparatus comprising a control unit for controlling.

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