JP2001081550A - Reactive sputtering apparatus and method for producing film - Google Patents

Abstract

(57) [Problem] To provide a reactive sputtering apparatus capable of forming a high-quality optical thin film or superconducting thin film with little damage and composition deviation on a large-area substrate at a high speed. Aim. SOLUTION: Target 13 (side surface), 14 (bottom surface)
Has a cylindrical shape, a sputter gas is introduced from a bottom portion thereof by a sputter gas introduction system 30, a reactive gas is introduced from a gas ring 32 near the substrate 40, and reactive sputtering is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus and a sputtering method for forming a film on a substrate attached to a substrate holder by sputtering a target, and more particularly to a sputtering gas containing a reactive gas containing fluorine or oxygen. The present invention relates to a reactive sputtering apparatus and a method for producing a coating, which are introduced to produce a coating such as an optical thin film or a superconducting thin film.

[0002]

2. Description of the Related Art A parallel plate type magnetron sputtering apparatus, which has been widely used in the past, has a target, which is a thin film material, and a base mounted on a base holder, which are arranged in a vacuum chamber so as to face each other. This is an apparatus for forming a thin film on a substrate by generating plasma, sputtering a target, and depositing sputtered particles sputtered by sputtering on the substrate.

[0003] A film forming method using this apparatus is simpler than other methods, is effective for high-speed film formation, is effective for large-area film formation, and is characterized by excellent target life and the like.

In such a sputtering apparatus, in recent years, studies have been made on the sputtering of fluorides such as aluminum fluoride (AlF ₃ ) and magnesium fluoride (MgF ₂ ) as low refractive index materials in the field of optical films.

However, when a reactive gas such as NF ₃ or F ₂ gas is introduced to form a film of a fluoride material on a lens or the like, the negative ions of fluorine and a fluorine compound which fly out of the target are accelerated by the cathode sheath voltage. In addition, there were problems such as a composition shift of the film due to the generated high energy particles and damage to the film, and a problem that the film was not formed depending on the target material and sputtering conditions, and the substrate was etched on the contrary. .

[0006] To solve such a problem, several solutions described below have been proposed.

(1) The number of collisions with a gas is increased and the kinetic energy of high-energy particles is reduced by forming a film under a sputtering pressure condition higher than a normal pressure.

(2) The density of high-energy particles is reduced by using a strong magnetic field to lower the discharge impedance, lower the plasma sustain voltage, and lower the cathode sheath voltage.

(3) R of commonly used high frequency power supply
F-band frequency (13.56 MHz) is converted to VHF band (100M
The energy of the energetic particles is reduced by lowering the cathode sheath voltage by sputtering using a frequency of (Hz).

(4) An off-axis sputtering apparatus (Japanese Patent Laid-Open No. 06-17248) in which the substrate or the target is rotated by 90 degrees based on the arrangement of the parallel plate target and the substrate, or the sputtered surface is separated by a space. A facing target sputtering apparatus for forming a thin film on a substrate disposed on a side of a space between the target and a means for generating a magnetic field in a direction perpendicular to the sputtering surface (Japanese Patent Laid-Open No. 05-182911) With such a configuration, high-energy particles are prevented from directly colliding with the substrate surface.

[0011]

However, these solutions cannot sufficiently solve the problems caused by the high-energy particles, and also have the problems of lowering the film forming speed.

In the above-mentioned solutions (1) to (3), measures are taken such as forming a film under a sputtering pressure condition higher than a normal pressure, or using a strong magnetic field or a VHF band frequency. In both cases, the self-bias voltage applied to the target decreases under the condition that the discharge impedance decreases. By lowering the self-bias voltage, high-energy particles (the energy drops in voltage) can be kept low, but damage to the substrate cannot be completely eliminated. Further, the film formation rate is reduced.

In the case of the above-described off-axis type sputtering apparatus (4), the target and the substrate are arranged side by side by rotating the substrate or the target by 90 degrees from the arrangement of the parallel plate target and the substrate. It is possible to form a film with less damage due to negative ions formed in the step (1). However, because of the side-surface arrangement, the film forming method is greatly sacrificed in film forming speed.

Further, when sputtering is performed on a material in which negative ions are easily formed with a facing target sputtering apparatus (Japanese Patent Laid-Open No. 05-182911), the substrate faces each other with a space therebetween, taking advantage of the features of the facing target. ,
Although it is possible to form a film with less damage due to negative ions formed on the surface of the target, a phenomenon is observed in which the erosion region of the target is concentrated at the center of the target with an increase in the power applied to discharge.

This phenomenon is particularly remarkable when the target is a non-magnetic material. Such concentration of the erosion region not only lowers the film forming speed but also adversely affects the film thickness distribution. Further, in the case where a large power is applied in order to increase the speed of sputtering, it causes a spark, which is preferable. Not something.

In order to overcome the above drawbacks, the present invention has developed a reactive sputtering apparatus equipped with a sputtering cathode different from the conventional one, and has developed an optical film made of a high-quality oxide film or fluoride film with little damage or composition deviation. Thin films and superconducting thin films
It is an object of the present invention to provide a reactive sputtering apparatus capable of forming a film on a large-area substrate at a high speed.

[0017]

SUMMARY OF THE INVENTION The present invention is a reactive sputtering apparatus for introducing a sputtering gas and a reaction gas, sputtering a target, and forming a film on a substrate. Means for introducing, and the target has a concave surface facing the base, the concave surface has a cylindrical shape or a substantially elliptical column shape, and a sputter gas is introduced to the bottom surface of the target. The present invention relates to a reactive sputtering apparatus characterized by having means.

The normal line at an arbitrary position on the side surface of the target does not cross the film-forming surface of the substrate.

Preferably, the side surface of the target is composed of a plurality of stages of targets, one of which has a means for detecting the surface state of the target, and the detecting means has a constant power supplied from a sputtering power source. The applied voltage or the self-bias voltage. Further, there is provided means for controlling the flow rates of the sputtering gas and the reaction gas so that the applied voltage or the self-bias voltage is constant.

Preferably, a target cooling means and one or more magnetron magnetic field forming means are provided on the outer surface of the target. As the magnetron magnetic field forming means, for example, a ring-shaped magnet is mentioned as a preferable embodiment.

Further, in the reactive sputtering apparatus of the present invention, it is preferable that the bottom surface of the target is a metal porous target.

The sputter gas used in the reactive sputtering apparatus of the present invention is one or more inert gases selected from helium, neon, argon, krypton, and xenon. The reaction gas is a reaction gas containing fluorine or oxygen.

Further, the present invention relates to a reactive sputtering method for forming a film on a substrate using the above reactive sputtering apparatus.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The reactive sputtering apparatus of the present invention comprises:
A reactive sputtering apparatus for forming an oxide film or a fluoride film on a substrate, particularly using a target such as Al, Y, Mg, etc., which easily generates negative ions, yttrium oxide (Y ₂
This is effective when an oxide film such as O ₃ ), aluminum fluoride (AlF ₃ ), and magnesium fluoride (MgF ₂ ) or a fluoride film is formed by reactive sputtering.

In the structure of the present invention, when the magnetron magnetic field forming means is provided, the coaxial magnetron discharge condition in which the electric field perpendicular to the target surface and the magnetic field almost perpendicular to the radial direction intersect on the sputtering surface on the side of the concave surface, Draws an arc (cycloid curve) perpendicular to the target surface, and can generate a magnetron discharge moving in the circumferential direction (closed loop) while ionizing by colliding with sputter gas molecules.

The ionized sputtering gas molecules accelerate and collide with the target surface biased to a negative potential to start sputtering.

As the sputtering gas, for example, one or more inert gases selected from helium, neon, argon, krypton, and xenon are used.

In the present invention, in particular, a target in which negative ions such as Al, Y and Mg are easily generated is used, and yttrium oxide (Y ₂ O ₃ ) or aluminum fluoride (Al
A case in which an oxide film such as F ₃ ) or magnesium fluoride (MgF ₂ ) or a fluoride film is formed will be considered.

When reactive sputtering is performed by a usual parallel plate type magnetron sputtering apparatus, a thin yttrium oxide (Y
Compound films such as ₂ O ₃ ), aluminum fluoride (AlF ₃ ), and magnesium fluoride (MgF ₂ ) are formed. When the sputtering surface on which the compound film is formed is sputtered, negative ions or a compound in which the negative ions are bonded are partially formed, and the formed negative ions are accelerated by an ion sheath voltage and have a large kinetic energy and directionality. Becomes

In general, a negative ion or a compound to which a negative ion is bonded is very unstable, so that it is neutralized by collision with gas molecules to form neutral particles. For this reason, neutral particles having directionality and large kinetic energy collide with a substrate disposed in front and cause large damage.

Further, depending on the sputtering conditions, negative ions colliding with the substrate surface (neutral particles during flight)
In some cases, the etching rate may be higher than the film forming rate, and the film may not be formed.

On the other hand, in the configuration of the present invention, the target has a concave surface facing the base, and the concave surface has a cylindrical shape or a substantially columnar shape. That is, the target used in the present invention has a sputtered surface on the side surface portion and the bottom surface portion of the concave surface.

The negative ions generated on the sputtering surface on the side surface of the target are accelerated toward the center of the target by the sheath voltage. Since negative ions have high reactivity, they collide with gas molecules having a low mass during flight and lose their electric charge to become neutral particles. At this time, since the mass number of the negative ion is larger than that of the gas molecule, the orbital change due to collision hardly occurs. In this way, high energy neutral particles derived from negative ions collide with the facing target.

On the other hand, sputtered particles emitted from the target surface by sputtering have an emission angle distribution,
Since the particles are emitted in various directions, the particles emitted in the direction of the substrate travel straight without being affected by an electric field and a magnetic field, and are deposited on the substrate.

However, since the base and the bottom surface of the target are opposed to each other, the negative ions or the compound formed by binding the negative ions formed on the bottom surface of the concave target reach the base film formation surface, and the film quality and the film formation speed are reduced. There is no possibility that this will happen.

Particularly, a compound or the like to which a negative ion having a large mass has a large energy has a high sputtering rate, and when the sputtering surface is suitable for a substrate, a holder, a vacuum member or the like other than the target, This may cause damage to the film and contamination of impurities into the film.

Therefore, in the present invention, the sputtering gas is introduced from the bottom of the target having a concave surface to separate the reaction gas from the sputtering gas, thereby further reducing damage to the film and mixing of impurities into the film. We are taking measures.

That is, by introducing the sputter gas from the bottom, the sputter gas is mainly filled in the concave target space, and the gas can be separated from the reaction gas, or the concave target space goes to the concave bottom. As the concentration of the sputtering gas becomes higher, a concentration gradient is formed, and the intrusion of the reaction gas containing oxygen and fluorine can be suppressed. Therefore, generation of negative ions at the bottom surface of the concave surface is suppressed.

In the vicinity of the opening of the concave target, there is intrusion of the reaction gas, but a part of the reaction gas is consumed by reacting with the sputtered sputtered particles, and the remaining reaction gas is proportional to the concentration gradient from the vicinity of the opening of the concave target. A compound film is formed. As a result, the formation of the compound film can be suppressed to the partial region of the side surface of the concave target. Even if a compound film is formed on the side surface of the concave target and negative ions are formed, the arrangement is such that the normal line at an arbitrary position on the sputtering surface does not intersect with the substrate deposition surface of the substrate holder, so that the negative ions No damage is done.

The concave surface of the target of the present invention has a cylindrical shape as shown at 131 in FIG. 4A or one shown at 132 in FIG. It has such a substantially elliptical column shape. The substantially elliptical column shape includes a bottom shape including an ellipse or a substantially elliptical shape (an oval shape).

As for the material of the target bottom surface,
It is preferable to use a metal porous target obtained by compression-molding fine powder with the same material as the target side surface. By using such a porous material and supplying the sputtering gas through the porous holes, the sputtering gas can be supplied uniformly, and the formation of the compound film due to the reaction gas on the target surface can be suppressed, which is more preferable. The pore size and porosity of the porous body can be appropriately determined according to the amount of the sputtering gas to be supplied.

When the bottom surface of the target is not made of a porous material, a sputter gas introduction hole 134 may be provided in the target bottom surface 133 as shown in FIG.

Further, in order to stabilize the process,
A means for detecting a target surface state and a control means are provided.
FIG. 3 is a diagram showing a change in voltage applied to the target when the power supplied to the target and the sputtering pressure are kept constant and the ratio between the sputtering gas and the reaction gas is changed.

When the target surface is in a metallic state, a large negative voltage is exhibited, and as the reaction gas flow rate is gradually increased, the target surface changes from a mixed state of metal and compound formation to a state in which the entire surface is covered with compound formation. Accordingly, the target applied voltage shows a low value.

In the present invention, preferably, the side surface target having the concave surface may be formed in a plurality of stages, and the applied voltage of a part of the target may be measured to determine the target surface state. The reaction gas and sputter gas flow rates are controlled so that the target surface state and the sputtering pressure are always constant. In this way, by monitoring the target surface state of a part of the concave target and controlling the flow rate of the reaction gas and the sputtering gas so as to be constant, the concentration gradient of the target internal space is made constant, and the target bottom surface part is formed. Since gas separation is possible, the metal portion of the target is always exposed at the bottom surface of the concave surface, which is a problem, so that metal sputtering is exposed, thereby preventing generation of negative ions.

As described above, in the present invention, the target is formed into a concave shape, an inert gas as a sputter gas is supplied from the bottom of the target, and a reaction gas is introduced into the vicinity of the substrate. In the space, a concentration gradient between the inert gas and the reaction gas is formed.
In the vicinity of the concave target opening where the reaction gas enters, the normal of the target surface is arranged so as not to intersect with the base,
Even if negative ions are formed, the film formed on the substrate is not damaged. On the other hand, on the concave bottom surface where the normal line of the target surface intersects with the substrate, the gas separation of the inert gas and the reactive gas is achieved, and the metal portion becomes exposed metal sputtering, thereby preventing the generation of negative ions.

As described above, by enabling reactive sputtering without negative ion damage as compared with the prior art, it is possible to obtain a high quality optical thin film or superconductive thin film with less composition deviation.

[0048]

The present invention will be described in further detail below with reference to examples.

Example 1 FIG. 1 is a sectional view of one embodiment of the reactive sputtering apparatus of the present invention.

In FIG. 1, reference numeral 10 denotes a vacuum chamber, 2
Reference numeral 0 denotes an exhaust system including a vacuum pump for exhausting the chamber 10, reference numeral 30 denotes a sputtering gas introduction system, and reference numeral 31 denotes a reaction gas introduction system. As shown, a target holder 12 fixed to the chamber 10 via an insulating member 11 is provided in the vacuum chamber 10, and an integrated cylindrical target 13 having a concave cross section is provided in the holder 12. It is set up. Further, on the bottom surface of the cylindrical target 13, a metal porous target 14 obtained by compression-molding fine powder with the same material as the target is provided.

On the outer surface of the target 13, a plurality of ring-shaped permanent magnets 15, which are magnetic field generating means, are arranged in parallel to the sputter surface on the inner surface of the cylindrical target 13.

Cooling pipes 161 and 162 are provided on the target 13 and the target holder 12 corresponding thereto.
The cooling water circulates through the inside of the water-cooling jacket 17 through the, and the targets 13 and 14 and the permanent magnet 15 are cooled.

The orientation of the magnetic poles of the ring-shaped permanent magnet 15 is shown in FIG.
And the magnets are arranged so that the magnetic field 50 can form a closed loop with each magnet.

Reference numeral 18 denotes a shield plate for shielding discharge, which serves to prevent sputtering of materials other than the target material to prevent impurities from being mixed into the thin film, as well as to prevent deposition of the target holder 12, the insulating member 11, etc. Works as well.

A substrate holder 41 for holding a substrate 40 on which a thin film is to be formed is provided on the side facing the concave target bottom surface 14. A gas ring 32 for introducing a reaction gas is provided near the base holder side of the base holder 40 and the concave target opening, and a shutter plate 19 having an opening / closing mechanism at the center is provided.

On the other hand, a power supply means 60 composed of a direct current, a high frequency power supply or a superposition thereof for supplying a sputtering power has a plus side connected to the ground and a minus side connected to the target holder 12 and the targets 13 and 14. A shutter 19 is provided between the substrate 40 and the target 14 to protect the substrate 40 from adhering a film during pre-sputtering.

Further, the targets 13 and 14 are set as shown in FIG.
By making the shape of a substantially elliptical cylinder (oval shape) as shown in 132, and optimizing the major axis length y and the minor axis length x of the substantially elliptical opening (same for the bottom surface), It is possible to correspond to a large-area substrate that moves or rotates the front surface. Note that the major axis length and the minor axis length mean the length of the longest axis and the length of the shortest axis among the axes passing through the central portion of the substantially elliptical shape.

Next, an inert gas such as argon or helium is introduced from the sputtering gas introduction system 30 into the concave target space through the porous target 14, and oxygen (O _2), which is likely to generate negative ions during sputtering, is further introduced. )
Gas such as nitrogen, nitrogen trifluoride (NF ₃ ), fluorine (F ₂ ) diluted with an inert gas, or the like, is introduced from a reaction gas supply system 31 through a gas ring 32 for introducing the reaction gas to the vicinity of the substrate holder. , High frequency or superimposed power is applied. On the sputtering surface of the target 13, a magnetic field parallel to the sputtering surface and a vertical electric field are formed by the ring-shaped permanent magnet 15 described above.

When the magnetic field and the electric field are formed vertically in this manner, the electrons moved by the electric field applied to the target are bent by the magnetic field and rotate in the circumferential direction of the target while performing cycloidal motion. Cycloidally moving electrons have a longer flight distance and a higher probability of colliding with sputter gas molecules. The gas molecules that collide with the electrons are ionized to form a magnetron discharge. Since a negative voltage is applied to the targets 13 and 14 from the power supply means 60, the ionized gas molecules are attracted while accelerating to the sputtering surfaces of the targets 13 and 14 and collide with the targets to strike out the target material. Magnetron sputtering occurs.

On the other hand, the sputtering gas supplied from the hole of the metal porous target 14 on the bottom surface of the concave target made of the same material as the side surface of the concave target, and the reaction gas supplied from the gas ring 32 near the substrate. The concentration of
In the concave target space, a gas concentration gradient is formed due to consumption by the reaction with the sputtered material and a pressure difference due to conductance.

At this time, since a reaction gas enters the target surface near the opening of the target 13, positive ions, neutral particles, electrons, and negative ions are generated during sputtering. The generated negative ions are repelled because they have the same polarity as the target voltage, and are accelerated by the ion sheath almost perpendicular to the sputtering surface. The accelerated negative ions collide with the sputter gas molecules in flight, become high-energy neutral particles, and collide with the opposing target, causing a sputtering phenomenon in which the target material is beaten. Similarly, since the invasion of the reaction gas is suppressed on the sputtering surface of the bottom target 14 facing the base, the metal sputtering state where no negative ions are generated is obtained, and a film without damage to the base can be obtained.

In order to form a good thin film on the substrate surface, the following two points are important.

1) The reactant gas required by the flying sputtering particles is sufficiently supplied.

2) An adequate amount of assist energy required for the reaction is sufficiently supplied. Here, the assist energy indicates a potential difference (about several tens of volts) between the plasma and the substrate, and a part of the positively ionized sputter gas ions and reactive gas ions are accelerated by this voltage and enter the substrate. These ions having a certain energy and incident on the substrate not only promote the reaction on the substrate surface but also have the effect of densifying the film quality.

In the present invention, the ratio of the reactant gas to the sputter gas cannot be reduced so much because the gas is separated. Therefore, it is preferable that the adjustment be performed at the sputtering speed. However, in the power adjustment of the power supply means, the assist energy of 2) changes, so in the present invention, the adjustment is performed by changing the introduction amount of the gas type of the sputtering gas. Specifically, the film formation rate is optimized by changing the ratio of the heavy argon gas to the light He gas.

The helium gas has a higher ionization energy than the argon gas, and is 15.8 eV, 2
It has characteristics such as a long ion life of 4.6 eV, and also has the effect of accelerating the reaction by the Penning effect.

As described above, a high quality film can be formed by optimizing the film forming speed, the flow rate of the reaction gas, the assist energy and the like.

In the above target configuration, an appropriate concentration distribution of the sputtering gas and the reactive gas is formed in the concave target space. Then, on the sputter surface near the opening where the reaction gas enters, the generated negative ions sputter the opposing target surface because of the arrangement in which the normal line of the sputter surface does not cross the base. In addition, on the bottom sputtering surface, invasion of the reaction gas is suppressed and gas separation can be performed, so that metal sputtering is performed without generating negative ions. As described above, the gas is separated at the bottom surface of the concave target, resulting in metal sputter without generation of negative ions. On the side surface where the reaction gas enters, the negative ions formed on the sputter surface (higher due to collision during flight) are formed. Energy neutral particles) are sputtered by both positive ions formed by plasma and high energy neutral particles, such as by colliding with an opposing target surface, so that the deposition rate can be increased. Further, high-energy neutral particles incident on the substrate surface can be reduced as much as possible, and a favorable thin film with less composition deviation and less damage can be formed.

The present invention also has the following advantages. The magnetron sputtering surface formed by the targets 13 and 14 and the substrate substantially surround the entire area, and the sputtered particles sputtered from the sputtering surface adhere to the substrate or the sputtering surface. The particles adhering to the target surface are re-sputtered and adhere to the substrate, which has the advantage of increasing the effect of capturing sputtered particles and improving the utilization efficiency of the target.

Example 2 FIG. 2 is a sectional view of an embodiment of the reactive sputtering apparatus of the present invention.

The difference between FIG. 1 of the first embodiment and FIG. 2 of the second embodiment is that the target 13 is made of insulating materials 110, 111 and 112.
Are independently divided into 13A and 13B through
A power supply means 60 is connected to the A and 14 targets, and a power supply means 61 is similarly connected to 13B. In addition, a voltmeter 70 for measuring a target voltage during sputtering and a control system 71 for controlling the flow rates of the sputtering gas introduction system 30 and the reaction gas introduction system 31 so that the measured value is constant are added to the target 13B. It was done.

When the sputtering pressure is constant, the target 13
A constant high-frequency power or a power at which a product of a DC current and a DC voltage is constant is applied to a magnesium (Mg) target of B to perform sputtering by changing a flow ratio of Ar as a sputtering gas and NF ₃ as a reaction gas. The target voltage changes according to the target surface state as shown in FIG.

When the surface of the target 13B is in the state of magnesium metal and the magnesium metal is sputtered, a large negative voltage is exhibited. When the flow rate of the NF ₃ gas as a reaction gas is gradually increased, the target surface forms a compound with the metal. Changes from the mixed state to the state where the entire surface is covered with the formation of the compound, and the voltage applied to the target accordingly shows a small negative voltage value. A concave side surface target 13 and a double magnetron magnetic field arrangement in which the polarity of the outer magnetron magnetic field is inverted are formed in two parts, and the target 13B on the opening side thereof is formed.
And the self-bias voltage are measured by a voltmeter 70, and the control system 71 controls the NF ₃ gas and Ar gas flow rates so that the target surface state and the sputtering pressure are always constant.

In actual film formation, the Ar gas flow rate is set to 1
00 sccm, a NF ₃ gas flow rate of about 30 sccm, and a DC power supply as a power supply means. The target applied voltage was set at a target voltage of −350 V close to the region B in the region where the rate of change from A to B in FIG. And set NF ₃ so that the target applied voltage is constant.
It is preferable to control the gas and Ar gas flow rates. At this time,
The target applied voltage applied to the targets 13A and 14 shows a voltage change in the vicinity of the region A, and a magnesium fluoride film having good characteristics without negative ion damage was obtained.

Therefore, according to the present invention, the target shape is concave, the inert gas is supplied from the bottom surface of the target, and the reaction gas is introduced into the vicinity of the substrate. Then, a concentration gradient of the reaction gas is formed. Furthermore, by monitoring the target surface state of a part of the concave target, and controlling the flow rate of the reaction gas and the sputtering gas so as to be constant, the concentration gradient in the internal space of the target is made constant, and the gas at the target bottom part Separation is possible, and on the bottom surface of the concave target where the normal line of the target surface intersects with the substrate, the metal portion of the target always becomes exposed metal spatter, thereby preventing generation of negative ions.

In the vicinity of the concave target opening where the reaction gas enters, the normal line of the target surface does not intersect with the substrate, so that even if negative ions are formed, the film formed on the substrate may be damaged. Absent.

As described above, by enabling reactive sputtering without negative ion damage as compared with the prior art, a high quality optical thin film or superconducting thin film having a small composition deviation can be obtained.

[0078]

As described above, the present invention has the following effects.

First, on the side surface of the target having a concave surface, generated sputtered particles are unlikely to reach the substrate deposition surface, and are less likely to damage the substrate deposition surface.

Second, a reaction gas is introduced from near the substrate,
By introducing sputtering gas from the bottom of the concave surface,
It suppresses the invasion of the reaction gas into the space inside the target, and particularly suppresses the generation of negative ions at the bottom of the concave surface facing the substrate deposition surface. As a result, even when the bottom of the concave surface faces the substrate, it is possible to suppress damage to the substrate deposition surface.

Third, in the present invention, it is not necessary to lower the self-bias voltage, and the target is not arranged on the side surface with respect to the substrate, so that high-speed film formation is possible.

As described above, in addition to the advantages of the conventional parallel plate magnetron sputtering, high-speed low-temperature sputtering can be performed. In addition, a target material in which negative ions are easily generated, which is impossible with the conventional parallel plate magnetron sputtering, is used. Use, high quality oxide film with less composition deviation and damage,
An optical thin film or a superconducting thin film made of a fluoride thin film or the like can be formed. Further, the sputtering can be performed at a higher speed, and the efficiency of capturing sputtered particles is high.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reactive sputtering apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a reactive sputtering apparatus according to a second embodiment of the present invention.

FIG. 3 is a graph showing a change in target voltage when a reaction gas / sputter gas ratio is changed.

FIG. 4 is a view showing a shape of a target used in the present invention.

FIG. 5 is a diagram showing a sputter gas inlet provided at the bottom of the target.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum chamber 11, 110, 111, 112 Insulating member 12 Target holder 13, 13A, 13B Cylindrical target 14 Porous target 15 Permanent magnet 161, 162 Cooling pipe 17 Water cooling jacket 18 Shield plate 19 Shutter plate 20 Exhaust system 30 Sputter gas Introducing system 31 Reaction gas introducing system 32 Gas ring 40 Substrate 41 Substrate holder 50 Magnetic field 60, 61 Power supply means 70 Voltmeter 71 Control system 131 Cylindrical target 132 Substantially elliptical column target 133 Cylindrical target bottom surface 134 Sputtering gas inlet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuyuki Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Ryuji Bilo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Hidehiro Kanazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 4K029 BC04 BC07 CA06 CA13 DA04 DA10 DC13 DC25 DC39 DC42 EA04

Claims (11)

[Claims] 1. A reactive sputtering apparatus for introducing a sputtering gas and a reactive gas, sputtering a target, and forming a film on a substrate, comprising a means for introducing a reactive gas near the substrate. And, the target has a concave surface facing the base, the concave surface has a cylindrical shape or a substantially elliptical column shape, and has means for introducing a sputtering gas to the bottom surface of the target. Reactive sputtering equipment. 2. The reactive sputtering apparatus according to claim 1, wherein a normal line at an arbitrary position on the side surface of the target does not intersect with a film forming surface of the substrate. 3. The reactive sputtering apparatus according to claim 1, wherein a side surface of the target is constituted by a plurality of stages of targets, and one of the side surfaces has means for detecting a target surface state. 4. The reactive sputtering apparatus according to claim 3, wherein said means for detecting the target surface state is means for detecting an applied voltage of a constant power supplied from a sputtering power supply or a self-bias voltage. 5. A reactive sputtering apparatus according to claim 4, further comprising means for controlling the flow rates of said sputtering gas and said reactive gas so that said detected applied voltage or self-bias voltage becomes constant. . 6. The reactive sputtering apparatus according to claim 1, further comprising a target cooling unit and one or more magnetron magnetic field forming units on an outer surface of the target. 7. The reactive sputtering apparatus according to claim 6, wherein said magnetron magnetic field forming means is a ring-shaped magnet. 8. The reactive sputtering apparatus according to claim 1, wherein the bottom surface of the target is a metal porous target. 9. The sputtering gas selected from helium, neon, argon, krypton, and xenon.
The reactive sputtering apparatus according to claim 1, wherein the reactive sputtering apparatus is a kind or a plurality of kinds of inert gases. 10. The reactive sputtering apparatus according to claim 1, wherein the reactive gas is a reactive gas containing fluorine or oxygen. 11. A method for producing a coating film on a substrate using the reactive sputtering apparatus according to claim 1.