JP2552700B2 - Plasma generating apparatus and thin film forming apparatus using plasma - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses a plasma generation device capable of forming high-density plasma and various thin films at high speed and high efficiency by utilizing sputtering by high-density plasma. The present invention relates to a novel thin film forming apparatus for continuously and stably forming for a long time.

[Prior Art] Conventionally, a so-called sputtering apparatus for forming a film by sputtering a target as a thin film forming element in plasma has been widely used in various fields for forming a thin film of various materials. Among them, a normal two-pole (rf, dc) sputtering device in which the target 1 and the substrate 2 are opposed to each other as shown in FIG. 22 is the most general, and the vacuum chamber 4 having the target 1 and the substrate 2 for depositing a thin film is used. It is composed of a gas introduction system and an exhaust system (not shown), and generates plasma inside the vacuum chamber 4.

In order to increase the film deposition rate with a conventional sputtering apparatus, it is necessary to keep the plasma at a high density.
In the sputtering equipment typified by Fig. 22, the higher the plasma density, the more rapidly the target applied voltage rises, which causes the substrate to be rapidly heated by the impact of high-energy particles or high-speed electron incidence in plasma. In addition, the crystal of the formed film itself is damaged. Therefore, the high speed sputter deposition can be applied only to a specific heat resistant substrate, film material and film composition.

In addition, in the film formation by the conventional sputtering device, the gas and particles in the plasma are not sufficiently ionized, and most of the sputtered neutral particles as film deposition elements enter the substrate as neutral particles. Therefore, the activity is not sufficient from the viewpoint of reactivity. Therefore, to obtain some oxides and thermal non-equilibrium substances, a high substrate temperature of about 500 ℃ -800 ℃ was required. Moreover, most of the electric power supplied to the plasma is consumed as thermal energy, and the ratio of the electric power used for plasma formation (ionization) that constitutes the supplied electric power is low, so that there is a drawback that the power efficiency is low.

Furthermore, the conventional sputtering apparatus has a drawback in that discharge cannot be stably formed at a low gas pressure of 10 ⁻³ Torr or less, and impurities are trapped in as many films as that.

Sputter-type plasma deposition device by microwave discharge using electron cyclotron resonance (ECR) (JP-A-60-
No. 50167) and a thin film forming apparatus utilizing confinement of electrons by a mirror magnetic field (Japanese Patent Laid-Open No. 62-222204) have been proposed, and they have attracted attention as excellent thin film forming apparatuses utilizing various characteristics.

However, when viewed as a high-speed film forming technique using sputtering, secondary electrons (γ
It is important to efficiently confine electrons), but these technologies do not sufficiently confine secondary electrons, and the energy of high-energy electrons cannot be effectively transferred to plasma. It's hard to say enough.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned conventional drawbacks, an apparatus capable of generating high-density plasma in a gas at a low pressure, and sputtering using the plasma to form a sample substrate. An object of the present invention is to provide a thin film forming apparatus capable of continuously forming a high quality thin film at a high speed and with a high efficiency while keeping it at a low temperature.

[Means for Solving the Problems] In order to achieve such an object, the plasma generating apparatus of the present invention includes a plasma generating chamber for introducing a gas to generate plasma, and a plasma generating chamber coupled to the plasma generating chamber. A microwave introduction window for introducing microwaves in a direction, a ring-shaped first target and a cylindrical second target made of respective sputtering materials provided at both ends of the plasma generation chamber, 1 and 2
At least one power supply for applying a negative voltage to each of the targets of the plasma generation chamber, and forming a magnetic field inside the plasma generation chamber, and entering from one of the first and second targets to the other. A magnetic field forming means for generating a magnetic flux is provided, and the microwave is introduced from the center of the ring-shaped target.

The thin film forming apparatus of the present invention is characterized in that the above-described plasma generation apparatus further comprises a sample chamber which is coupled to the plasma generation chamber and has a substrate holder therein.

[Operation] The present invention generates a high-activity high-density plasma,
Sputtering is performed using the plasma, and the conductivity of the generated film material does not hinder the film formation while the sample substrate is kept at a low temperature, and high quality thin films can be continuously formed at high speed and high efficiency. It is a thing. That is, according to the present invention, plasma is generated and heated by electron cyclotron resonance (ECR), and the high density plasma is used for sputtering.
Both extraction of low-energy ions of tens of ev from ev and generation of highly active plasma are made compatible. In the present invention, microwaves are introduced in the axial direction of plasma, so that power efficiency is high.

Furthermore, since a target structure that reflects high-energy electrons into the plasma is adopted, high-speed film formation can be realized.

If a vacuum waveguide with a yoke surrounding it is used, the magnetic field strength in the vacuum waveguide is weak and the magnetic field strength changes sharply at the boundary with the plasma generation chamber. Since the tube is bonded to the plasma generation chamber, the acceleration of plasma to the vacuum waveguide is suppressed, and as a result, the reflection of microwaves due to the adhesion of the conductive material film on the microwave introduction window can be ignored, and metal such as metal It is possible to continuously form a conductive material film stably for a long time.

EXAMPLES The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of a thin film forming apparatus according to the present invention. The plasma generation chamber 11 includes a plasma generation unit 11P and a target holding unit 11S. Plasma generation chamber 1
A gas for generating plasma is introduced into 1 through an inlet 11A. A microwave introduction window 6 is connected to the plasma generation chamber 11. The microwave introduction window 6 is further connected to a microwave waveguide 7, and microwaves are introduced into the plasma generation chamber 11 from a microwave source connected to a microwave introduction mechanism such as a matching device, a microwave power meter, an isolator, etc. (not shown). It is supplied in the axial direction of the plasma. In this embodiment, a quartz glass plate is used for the microwave introduction window 6 arranged in a portion which is not directly visible from the target placed in the plasma generation chamber 11. As the microwave source, for example, a magnetron of 2.45 GHz is used. A ring-shaped target 14 is provided on the top inside the plasma generation chamber 11, and a cylindrical target 13 is provided on the inner side surface of the target holder 11S.

A method of attaching the targets 13 and 14 to the plasma generation chamber is shown in FIGS. 2A and 2B. As shown in the figure, the target 13 is detachably fixed to a water-coolable metal support 13B, and the support 13B is fixed to the plasma generation chamber by a screw lid 13C.
It is fixed to the wall 11B on the side of 11. The support 13B and the wall 11B are insulated by the insulator 13D. Target 1 as well
4 is detachably fixed to a water-coolable metal support 14B, which is fixed to a wall 11C by a screw lid 14C via an insulator 14D. The protruding ends 13E and 14E of the supports 13B and 14B also serve as electrodes, and a negative voltage can be applied to the targets 13 and 14 from the DC power supplies 13A and 14A.

The plasma generation unit 11P adopts, as an example, a circular cavity resonance mode TE ₁₁₃ as a condition of the microwave cavity resonator, and increases the electric field strength of the microwave by using a cylindrical shape having a diameter of 20 cm and a height of 20 cm in the inner ring, The efficiency of microwave discharge was increased. The lower end of the plasma generation unit 11P, that is, the interface with the target holding unit 11S, has a hole with a diameter of 10 cm, and its surface also serves as a reflection surface for microwaves.
The plasma generation unit 11P acts as a cavity resonator.

At least one electromagnet 8 is provided on the outer circumference of the plasma generation chamber 11 to generate a magnetic field in the plasma generation chamber. At that time, each constituent condition is determined so that the condition of the electron cyclotron resonance (ECR) by the microwave is satisfied inside the plasma generation unit 11P. For example, the frequency 2.45GHz
For the microwave of, the ECR condition is a magnetic flux density of 875G, so the electromagnets 16A and 16B at both ends are configured to obtain a magnetic flux density of up to 2000G, for example.
Is realized somewhere inside the plasma generation unit 11P. Not only is the ECR efficiently energizing the electrons inside the plasma generation unit 11P, but this magnetic field also prevents the generated ions and electrons from being dissipated in the direction perpendicular to the magnetic field, and as a result, high energy is generated at low gas pressure. Density plasma is generated.

The ring-shaped target 14 and the cylindrical target 13 have the electromagnet 8 on the surfaces of the ring-shaped target 14 and the cylindrical target 13.
Is installed so that the magnetic flux 5 due to the magnetic flux flows from one target to the other target.

It is desirable that the plasma generation chamber be water-coolable. In order to protect the side surfaces of the targets 13 and 14 from the plasma, it is preferable to provide shields 11D and 11E on the inner surface of the plasma generation chamber.

After the inside of the plasma generation chamber 11 is evacuated to a high vacuum, gas is introduced from the gas introduction port 11A to introduce microwaves and discharge is generated under ECR conditions to generate high density plasma. The magnetic flux between the targets prevents the secondary electrons (γ electrons) generated from the target surface from being dissipated in the direction perpendicular to the magnetic field,
Furthermore, it has the effect of confining the plasma, and as a result, a high-density plasma is generated in a low gas pressure. The target can be sputtered by the plasma to generate ions and neutral particles, which can be extracted as sputtered particles.

A sample chamber 9 is connected to the plasma generation chamber 11 below the plasma generation chamber 11. Gas can be introduced into the sample chamber 9 through the gas introduction port 9B and can be evacuated to a high vacuum by the exhaust system 9A. A substrate holder 2A for holding the substrate 2 is provided in the sample chamber 9, and an openable shutter (not shown) is provided on the substrate holder 2A. It is preferable that a heater is built in the substrate holder 2A so that the substrate can be heated, and a DC or AC voltage is applied to the substrate 2 to apply a bias voltage to the substrate during film formation,
It is desirable to configure the substrate so that it can be sputter cleaned.

FIG. 3 shows an example of the distribution of the magnetic field strength in the magnetic flux direction in the device shown in FIG. The magnetic field is a divergent magnetic field.

Here, with reference to FIG. 4, the plasma multiplication mechanism in the present embodiment will be described. Gas is introduced into the plasma generation chamber to generate plasma under ECR conditions. As described above, the water-cooled ring-shaped target 14 is installed on the inner upper surface of the plasma generation chamber. Further, a water-cooled cylindrical target 13 is installed at the sample chamber side outlet of the plasma generation chamber so as to surround the plasma.

The microwave introduction window 6 is arranged in the center of the ring-shaped target 14 so that microwaves are introduced into the plasma generation chamber 11 from the center of the ring-shaped target 14.

The magnetic flux 5 of the electromagnet is designed to run between the surfaces of the ring-shaped target 14 and the cylindrical target 13, that is, the magnetic flux enters from one target surface to the other target surface.

When the magnetic field changes spatially gently in this way, the electrons in the generated high-density plasma have a significantly higher mobility than the ions, and are bound by the magnetic flux 5 to move around the magnetic flux 5. While spirally moving, while maintaining its angular momentum, it is accelerated toward the substrate due to the magnetic field gradient.

By applying negative potentials V _a ^C and V _a ^P to the cylindrical target 13 and the ring-shaped target 14 facing the high-density plasma generated as described above, the ions in the high-density plasma are cylindrically shaped. The target 13 and the ring-shaped target 14 are efficiently drawn and sputtered. When the ions attracted to these targets collide with the target surface, secondary electrons (γ electrons) 15 are emitted from the target surface. The γ-electrons 15 are accelerated by the electric field created by the respective targets and are restrained by the magnetic flux 5 running on the surfaces of those targets, and move to the opponent's target at high speed while making a spiral motion. The γ electron 15 that reaches the target of the other party is also reflected by the electric field created by the target, and as a result, the γ electron
15 will be trapped in a spiral motion between both targets. The reciprocating motion of the γ-electron 15 is confined until its energy becomes smaller than the binding energy of the magnetic flux, and during that time, ionization is accelerated by collision with neutral particles and interaction with plasma.

Since the plasma is active, not only can the discharge be stably formed even at a lower gas pressure on the order of 10 ^-5 Torr, but the active species also play an important role in thin film formation. Thus, it is possible to form a thin film having good crystallinity even at a low substrate temperature.

In the thin film forming apparatus of the present invention, since the ionization rate of the plasma is high as described above, the neutral sputtered particles emitted from the target have a high rate of being ionized in the plasma, but the ionized target constituent particles are Further, the rate of so-called self-sputtering in which the target is sputtered and accelerated by the potential of the target becomes extremely large. That is, even when the plasma generating gas (for example, Ar) is extremely dilute, or when the gas is not used, the above-mentioned self-sputtering can be continued, and a high-purity film can be formed.

Next, the result of forming an AlN film using the device of the present invention will be described. After evacuating the vacuum of the sample chamber 9 to 5 × 10 ⁻⁷ Torr, nitrogen (N 2) gas was introduced at a flow rate of 2 cc / min, and the gas pressure in the plasma generation chamber was set to 3 × 10 ⁻⁴ Torr, and the micro Wave power 100-500W, cylindrical Al target 1
The film was formed by applying an electric power of 3 to 100 to 800 W. At this time, the sample stage was heated to 300 ° C. to form a film. As a result, the AlN film could be deposited stably and efficiently continuously for a long time at the deposition rate of 3 to 40 nm / min.

FIG. 5 shows an example of the discharge characteristics in this embodiment, and FIG. 6 shows the target input power dependence of the deposition rate. In this embodiment, the voltage applied to the ring-shaped target is -500V.
The nitrogen gas pressure was fixed at 3 mTorr and the microwave power was fixed at 300 and 80 W. As in this example, it is possible to generate sufficiently high-density plasma even when the voltages applied to the ring-shaped target 14 and the cylindrical target 13 are different, and when the voltages are the same, that is, both targets are electrically connected, it is sufficient. High-density plasma can be generated with high efficiency.

The average energy of the ions at this time changed from 5 eV to 30 eV.

The thin film forming apparatus of the present invention not only forms the AlN film,
It can be used for forming almost all thin films, and most reactive gases can be used as the introduction gas, not limited to nitrogen gas, and thereby reactive sputtering can be realized. Further, various compounds can be used as a target, and film formation of most materials can be realized.

FIG. 7 shows another embodiment of the present invention. Although the magnetic field gradient by the electromagnet 8 has a great influence on the energy of the ions accelerated in the substrate direction, the erosion distribution of the target, or the shape of the plasma, as shown in the present embodiment, the magnetic field gradient control is performed around the substrate or the like. Auxiliary electromagnets 16 can be installed to control them.

FIG. 8 shows the change in ion energy with respect to the current passed through the auxiliary electromagnet 16 in the embodiment of FIG. Here, the positive current corresponds to the case where the magnetic field direction formed by the auxiliary electromagnet 16 is the same as the magnetic field direction formed by the electromagnet 8, and the negative case corresponds to the opposite case. .

 FIG. 9 shows another embodiment of the present invention.

In the present embodiment, the microwave introduction window 6 is coupled to the plasma generation chamber 11 via the vacuum waveguide 10. Around the vacuum waveguide 10 connected to the plasma generation chamber 11 from the center of the ring-shaped target 14, a magnetic flux in the vacuum waveguide is absorbed, and a connection portion between the plasma generation chamber and the vacuum waveguide. The yoke 17 is installed so that the magnetic field strength changes sharply.

FIG. 10 shows an example of the magnetic field strength distribution in the magnetic flux direction in the embodiment shown in FIG.

The plasma breeding mechanism in this embodiment will be described with reference to FIG. As described above, when the magnetic field is gradually changing spatially, the electrons in the generated high-density plasma have an extremely large mobility as compared with the ions, and are confined by the magnetic flux 5 and thus the magnetic flux 5 While maintaining its angular momentum while spiraling around, it is accelerated toward the substrate due to the magnetic field gradient.

Around the vacuum waveguide 10, the yoke 17 absorbs the magnetic flux in the vacuum waveguide generated by the electromagnet 8 and causes a sudden change in magnetic field strength at the boundary between the vacuum waveguide and the plasma generation chamber. Are arranged.

Cylindrical target facing the generated high-density plasma
By applying a negative potential to the ring-shaped target 14 and the ring-shaped target 14, the ions in the high-density plasma are guided to the cylindrical target 13
And the ring-shaped target 14 is efficiently drawn to cause sputtering. When the ions attracted to these targets collide with the target surface, secondary electrons (γ electrons) 15 are emitted from the target surface. The γ-electrons 15 are accelerated by the electric field created by the respective targets, are restrained by the magnetic flux 5 running on the surfaces of the targets, and move to the opponent's target at high speed while making a spiral motion. The γ electrons 15 reaching the target of the other party are also reflected by the electric field created by the target, and as a result, the γ electrons 15 are confined in a spiral motion between both targets. The reciprocating motion of the γ-electron 15 is confined until its energy becomes smaller than the binding energy of the magnetic flux, and during that time, ionization is accelerated by collision with neutral particles and interaction with plasma.

When forming the conductive material film, if the microwave introduction window becomes cloudy, plasma cannot be generated for a long time. Here, when the microwave introduction window is simply separated from the plasma generation chamber and the vacuum waveguide is used, the resonance condition is achieved even in the vacuum waveguide as shown in FIG. Plasma is generated in the wave tube, and a dense plasma column 19 is generated. Moreover, since the plasma is accelerated in the microwave introduction direction, effective microwave power cannot be input. On the other hand, when the vacuum waveguide 10 surrounded by the yoke 17 is connected to the plasma generation chamber, the magnetic flux intensity in the vacuum waveguide 10 is low, as shown in FIG. Since the magnetic field strength of the boundary between the plasma generation chamber and the vacuum waveguide rapidly changes, plasma is not excited in the vacuum waveguide,
Moreover, it is not accelerated in the direction of the vacuum waveguide. As a result, the plasma is not accelerated in the microwave introduction direction. On the other hand, of the particles sputtered from the cylindrical target 13 or the ring-shaped target 14 installed in the plasma generation chamber 11, neutral particles that are not ionized are not affected by the magnetic field or electric field, and go straight from the target. Come flying. Therefore, by disposing the microwave introduction window 6 at a position that is not directly visible from the target, it is possible to prevent the microwave introduction window 6 from being fogged by sputtered particles. In this way, it is possible to continuously and stably form a film of almost any material, without depending on the conductivity of the generated film, and without depending on the film thickness, and without the microwave introduction window becoming cloudy. It is possible.

Next, the result of forming an Al film using the device of the present invention will be described. After exhausting the vacuum of the sample chamber 9 to 5 × 10 ⁻⁷ Torr, Ar gas was introduced at a flow rate of 2 cc / min, the gas pressure in the plasma generation chamber was 3 × 10 ⁻⁴ Torr, and the microwave power was 100. The film was formed with a power of ˜500 W and an electric power of 100-800 W applied to the cylindrical Al target 13. At this time, a film was formed at room temperature without heating the sample table. As a result, 10 ~
A at a deposition rate of 150 nm / min for a long period of time stably and efficiently
l The film could be deposited.

FIG. 14 shows an example of the discharge characteristics in this example, and FIG. 15 shows the dependence of the deposition rate on the target input power. In this example, the voltage applied to the ring target is -500V,
Ar gas pressure 0.3 mTorr, microwave power 300 and 80 W
It is fixed to. As in this example, it is possible to generate sufficiently high-density plasma even when the voltages applied to the ring-shaped target 14 and the cylindrical target 13 are different, and when the voltages are the same, that is, both targets are electrically connected, it is sufficient. High-density plasma can be generated with high efficiency.

The average energy of the ions at this time changed from 5 eV to 30 eV.

FIG. 16 shows still another embodiment of the present invention. Similar to the embodiment shown in FIG. 7, an auxiliary electromagnet 16 for controlling the magnetic field gradient is provided around the substrate, etc., and the energy of the ions accelerated in the substrate direction, the erosion distribution of the target, or the magnetic field given to the shape of the plasma is given. The influence of the gradient can be controlled.

FIG. 17 shows a change in ion energy with respect to a current flowing through the auxiliary electromagnet in the embodiment of FIG. Here, the positive current corresponds to the case where the magnetic field direction formed by the auxiliary electromagnet is the same as the magnetic field direction formed by the electromagnet, and the negative case corresponds to the opposite case.

18 to 21 show other embodiments of the present invention.

18 and 19 show the electromagnet 8 in the embodiment shown in FIGS. 1 and 9 replaced by two permanent magnets 12, respectively. These embodiments also operate in the same manner as the embodiments shown in FIGS. 1 and 9. Permanent magnet 12
It is also possible to use a combination of the and yoke.

FIGS. 20 and 21 show high frequency power as the voltage applied to the target in the embodiments of FIGS. 1 and 9, respectively. That is, as shown in FIGS. 20 and 21, the same effect can be obtained even if the rf power from the rf oscillator 20 is applied to the target through the matching circuit 21. Moreover, in this case, stable ion extraction can be performed even if the target has no conductivity.

[Effects of the Invention] As described above, according to the present invention, a microwave plasma generated by electron cyclotron resonance is generated, and a sputtering using this plasma is used to form a highly efficient low temperature film in a low gas pressure. It is possible to realize continuous and stable film formation for a long time regardless of the conductivity and film thickness of the film. Also, the energy of particles is from several eV to several tens eV
Since it can be freely controlled in a wide range up to, and high-activity plasma is used, a high-quality film with little damage can be continuously formed at low substrate temperature at high speed and high stability by using this apparatus.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the thin film forming apparatus of the present invention, FIG. 2 is a detailed sectional view showing attachment of a target, and FIG. 3 is a magnetic flux direction of the embodiment of the thin film forming apparatus shown in FIG. Magnetic field intensity distribution chart, FIG. 4 is a diagram for explaining the state of motion of fast secondary electrons (γ electrons) in the thin film forming apparatus of the present invention, and FIG. 5 is a discharge characteristic in the embodiment of the thin film forming apparatus of the present invention. FIG. 6 is a characteristic diagram showing an example, FIG. 6 is a characteristic diagram showing the target input power dependency of the film deposition rate in the embodiment of the thin film forming apparatus of the present invention, and FIG. 7 is another embodiment of the thin film forming apparatus of the present invention. Sectional view, FIG. 8 is a characteristic diagram showing the relationship between the auxiliary magnet current and the average ion energy, FIG. 9 is a sectional view of yet another embodiment of the present invention, and FIG. 10 is the thin film forming apparatus shown in FIG. 11 is a magnetic field strength distribution diagram in the magnetic flux direction in the embodiment of FIG. FIG. 12 is a diagram for explaining the state of motion of high-speed secondary electrons (γ electrons) in the thin film forming apparatus shown in FIG. 12, FIG. 12 is a plasma generation state diagram when simply using a vacuum waveguide, and FIG. 13 is a vacuum waveguide. And FIG. 14 is a characteristic diagram showing an example of discharge characteristics in the embodiment shown in FIG. 13, and FIG. 15 is a film in the embodiment shown in FIG. A characteristic diagram showing the target input power dependency of the deposition rate, FIG. 16 is a sectional view of another embodiment of the thin film forming apparatus of the present invention, FIG. 17 is a characteristic diagram showing the relationship between the auxiliary electromagnet current and the average ion energy, 18 to 21 are sectional views of still another embodiment of the present invention, and FIG. 22 is a sectional view of a conventional bipolar sputtering apparatus. 1 ... Target, 2 ... Substrate, 3 ... Plasma, 4 ... Vacuum tank, 5 ... Magnetic flux, 6 ... Microwave introduction window, 7 ... Microwave introduction tube, 8 ... Electromagnetic field generating magnet, 9 ... Sample chamber, 10 ... Vacuum waveguide, 11 ... Plasma generation chamber, 12 ... Permanent magnet, 13 ... Cylindrical target, 14 ... Ring target, 15 ... High-speed secondary electron (γ Electron), 16 …… auxiliary electromagnet, 17 …… yoke, 18 …… plasma acceleration direction, 19 …… dark plasma column.

Claims (5)

(57) [Claims] 1. A plasma generation chamber for introducing a gas to generate plasma, a microwave introduction window coupled to the plasma generation chamber for introducing a microwave in an axial direction of the plasma, and the inside of the plasma generation chamber. A ring-shaped first target and a cylindrical second target, each of which is made of a sputtering material, are provided at both ends of the plasma generation chamber, and a negative voltage with respect to the plasma generation chamber is applied to each of the first and second targets. At least one power source to be applied, and a magnetic field forming means for forming a magnetic field inside the plasma generation chamber and generating a magnetic flux from one of the first and second targets and entering the other, A plasma generation device in which a microwave is introduced from the center of a ring-shaped target. 2. The microwave introduction window is coupled to the plasma generation chamber via a vacuum waveguide, and the magnetic field generated by the magnetic field forming means is absorbed around the vacuum waveguide, The plasma generation according to claim 1, further comprising a yoke for reducing a magnetic field intensity in the vacuum waveguide and for rapidly changing the magnetic field intensity at a boundary between the vacuum waveguide and the plasma generation chamber. apparatus. 3. The plasma generating apparatus according to claim 1, wherein the microwave introduction window is installed in a portion which is not directly visible from the surfaces of the first and second targets. 4. A thin film formation, comprising: the plasma generation apparatus according to claim 1, further comprising a sample chamber having a substrate holder therein, the sample chamber being coupled to the plasma generation chamber. apparatus. 5. The thin film forming apparatus according to claim 4, further comprising auxiliary magnetic field forming means for correcting the magnetic field formed by the magnetic field forming means.