JP2003247065A - Thin film deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film deposition apparatus which can deposit a thin film of high quality in a highly uniform manner at a high speed by placing a plurality of materials for film deposition in one vacuum chamber. <P>SOLUTION: In this thin film deposition apparatus to deposit a thin film on a substrate by sputtering particles of the materials for depositing the film from a plurality of sputtering sources by using ions of plasma flow, a plasma generating means generates plasma by the electronic cyclotron resonance discharge, the axes of rotational symmetry of a target are intersected with each other on the axis of rotation of a substrate sample table in the plurality of sputtering sources, and inclined with respect to the axis of rotation of a rotary sample table, and the substrate sample table comprises a rotating means which rotates the target in an inclined manner so that the intersection of the axis of rotational symmetry of the target with the axis of rotation of the substrate sample table is located in the direction opposite to the target with respect to the sample substrate for depositing the film, and a moving means to move the substrate sample table in the vertical direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus used for manufacturing optical communication devices, optical devices, and electronic devices such as semiconductor devices and magnetic storage devices.

[0002]

2. Description of the Related Art An optical multilayer film formed by alternately stacking dielectric films having different optical refractive indexes is a non-reflective coating on glasses such as glasses and plastics, color separation prisms for video cameras, various types. It is used for optical filters and end face coating of light emitting lasers. In addition, recently, wideband optical wavelength division multiplexing (Dense Wavelength Division Division (Dense Wavelength Division
Ion Multiplexing (DWDM) communication)
It has come to be applied to a multiplexing filter and a demultiplexing filter used in the. In addition, the number of layers of the optical multi-layer film is very large, from several tens to several hundreds, and it is required that the film thickness and the film quality be even more precise than ever.

Here, the present optical wavelength division multiplexing (wavelength division mu (wavelength division mu)
The specifications required for the multiplexing filter and the demultiplexing filter used for the wireless communication (WDM) communication) will be described. Generally, the filter transmission width (or transmission band width) at -0.5 dB is used as the standard for evaluating the bandpass characteristics.
δW (F) and crosstalk transmission width δW at −25 dB
(C), the insertion loss and the ripple strength are used. The filter transmission width indicates the width of a bandpass signal through which an optical signal is transmitted, and the thinner the filter is, the more signals can be transmitted within the defined bandwidth. The crosstalk width indicates how close the bandpass signals can be to each other without interference, and the thinner the crosstalk width, the closer the bandpass signals can be arranged without interference. That is, both the filter transmission width and the crosstalk width are narrowed, so that the number of bandpass signals that can be used for communication in the defined band band increases. The insertion loss indicates the intensity difference between the maximum value of the bandpass signal and the ideal transmittance of 100%. Ripple is a phenomenon in which the transmittance locally decreases in a portion near the maximum value of a bandpass signal, and when ripple appears, a desired bandpass characteristic may not be obtained. The difference between the maximum value of the signal when the ripple occurs and the local transmittance reduction value is the ripple strength. A rectangular shape is required as an ideal bandpass characteristic.

At present, the bandpass filter which is mainly used has a filter transmission width of −2 dB or less at −0.5 dB.
Crosstalk transmission width at -25 dB is 4 nm to 8 nm
It has some characteristics. Also, the filter transmission width is already 1n.
Practical application of band-pass filters of m or less has been reached. The bandpass characteristics required for the next-generation broadband optical wavelength division multiplexing (DWDM communication) are required to have a filter transmission width of 0.1 nm, a crosstalk width of 0.2 nm to 0.8 nm, and an insertion loss of -1 dB or less. The ripple strength is -0.2 dB. Therefore, there has been a demand for an optimal design of bandpass characteristics and a highly accurate film forming technique for forming a filter structure.

Various forming apparatuses and forming methods have been tried in order to form an optical multilayer film having such band-pass characteristics. Since the number of layers of the optical multilayer film is very large, from several tens to several hundreds, the flatness of the interface between the films is required. This is because if the interface has minute irregularities, the communication light is scattered between the 100 layers and the characteristics are deteriorated. Furthermore, uniformity of film thickness and film quality, temperature dependence and wavelength selectivity,
Higher precision than ever has been required for long-term reliability. As a recent tendency, in addition to these, the demands on the economical efficiency and the productivity of filters are increasing, so that a film forming method capable of realizing a large area film forming, a high uniform film forming, and a high yield is desired.

The thin film used for the multilayer film is silicon
(Si), amorphous silicon (a-Si), hydrogen
Amorphous silicon (a-Si: H), silicon dioxide
Con (SiO₂), Tantalum pentoxide (Ta₂O_Five), Al
Mina (Al₂O₃), Titanium dioxide (TiO 2₂), Dioxide
Zirconium (ZrO₂), Hafnium dioxide (Hf
O ₂), Lanthanum dioxide (LaO₂), Cerium dioxide
(CeO₂), Antimony trioxide (Sb₂O₃), Trioxide
Indium (In₂O₃), Magnesium oxide (Mg
O), thorium dioxide (ThO₂) Oxides and
Binary or higher oxide or silicon oxynitride (Si
O_xN_x), Or silicon nitride (SiN), nitriding
Aluminum (AlN), zirconium nitride (Zr
N), hafnium nitride (HfN), lanthanum nitride (La)
N) and other nitrides and binary nitrides, or
Magnesium Fluoride (MgF₂), Cerium trifluoride
(CeF₃), Calcium difluoride (CaF₂), Fluoride
Lithium (LiF), trisodium hexafluoride aluminum
Mu (Na₃AlF₆) Fluoride, or binary
The above-mentioned fluorinated compounds are available.

At present, a sputtering method (sputtering method) is mainly used as a method for forming an optical multilayer filter used in the field of optical communication. The sputtering method does not require the use of dangerous gases or toxic gases, and the surface irregularities (surface morphology) of the deposited film are relatively good. It is connected. In particular, in the sputtering method, in order to obtain a film having a stoichiometric composition, there is provided a reactive sputtering device / method which supplies oxygen gas, nitrogen gas or hydrogen gas to prevent oxygen or nitrogen in the film from being lost. Promising.

Next, the situation of the semiconductor device will be described.
Large-scale integrated circuit (L) made on a silicon (Si) substrate
Sl) has been performed to improve the degree of integration of elements per unit area by miniaturizing the elements. When miniaturizing the device, the operating speed is improved by shortening the gate length of the MOS transistor having a structure of gate electrode / gate insulating film / semiconductor. Improvement of integration and operation speed by miniaturization is a driving force for LS1 technology development, and research and development are being carried out to break various limits. These can be miniaturized by the so-called scaling law, and the power supply voltage and the gate voltage are also reduced by the scaling law.

In order to operate the MOS transistor while keeping the gate voltage low, it is necessary to provide the semiconductor with a MOS capacitance enough to generate an inversion layer. Therefore, the gate insulating film can be thinned to secure the capacitance. I've been told. As a result, in recent years, the gate insulating film of a MOS transistor has become thinner, about 3 nm or less, so that the direct tunneling current dominantly flows. In particular, in devices such as mobile phones and mobile terminals including PDAs that require low power consumption, it is important to suppress tunnel current and power consumption.

Recently, an insulating film having a relative dielectric constant larger than that of a silicon dioxide (SiO ₂ ) film, which has been used as a gate oxide film, is used for the gate insulating film to keep the film thickness thick while securing the electric capacitance. Therefore, methods of suppressing the tunnel current are being actively studied.

Silicon oxynitride (SiO _x N _x ) and alumina (Al
₂ O ₃ ), titanium dioxide (TiO ₂ ), zirconium dioxide (ZrO ₂ ), hafnium dioxide (HfO ₂ ), lanthanum dioxide (LaO ₂ ), or a binary alloy oxide,
Silicon nitride (SiN), aluminum nitride (Al
N), zirconium nitride (ZrN), hafnium nitride (HfN), lanthanum nitride (LaN), or a binary alloy nitride is a strong candidate.

In addition, the high dielectric material described above
Studies have been conducted to select one or more and combine them in layers to form a single gate insulating film to enhance the effect. For example, by forming an extremely thin film having a high oxygen barrier property on a silicon substrate and forming a film having a high dielectric constant on the film, a high dielectric film can be formed while suppressing the silicon oxide layer formed at the interface. It can be formed and is intended to improve the characteristics as a gate insulating film.

Various methods have been studied as a method for forming these multi-layered gate insulating films. However, the formation of an ultrathin film, the controllability of the film thickness and the uniformity of the film quality are higher than those of the optical multi-layer film formation. Is required. Further, it is required to solve problems such as reduction of contamination of impurities and suppression of silicon interface layer. Methods using chemical vapor deposition (CVD) and RF plasma have been studied, but it is difficult to solve the problems of impurity mixing and interface control. In addition, the morphology (surface irregularities) of the insulating film itself is large, and many problems must be solved in order to form a multilayer. On the other hand, the reactive sputtering method is
It is considered to be promising because it has good surface morphology and can easily obtain a film having a stoichiometric composition.

As a target used in the sputtering method,
There are cases where a metal is used and cases where a target compound is used, but in general, a metal is easier to manufacture as a target and a high-purity one is obtained. The compound target requires a process such as sintering, and it is difficult to shape and adjust the composition, and impurities cannot be avoided.

Currently, as a method for producing an optical multilayer film device, an ion assisted vapor deposition method (IAD method), an ion beam sputtering method (IBS method), an ion plating vapor deposition method (IP method), and an advanced plasma source method (APS method). ), Etc. are the mainstream.

FIG. 13 shows a schematic diagram of the ion assisted vapor deposition method. The ion assisted vapor deposition device 100 includes an RF ion source 101 and an EB source target A in a vacuum chamber.
103, EB source target B105, electron beam evaporation source A102, electron beam evaporation source B104, rotation mechanism 1
Sample stage 108 having a 09 film thickness meter 1 for monitoring the film thickness
It is equipped with 06. The RF ion source 101 is attached to the bottom of the vacuum chamber, in which oxygen ions and argon ions are plasmatized to form an ion stream 110,
The substrate 107 is irradiated with ions.

The particles evaporated from the targets 103 and 105 provided in the electron beam evaporation sources 102 and 104 attached to the bottom of the vacuum chamber form a flow of sputtering raw material A111 and sputtering raw material B112. When the particles adhere to the substrate 107, the RF ion source 10
The plasma irradiation from 1 gives energy together with the substrate 107. Therefore, a dense film can be formed. This evaporation method uses an electron beam evaporation source and RF.
It has a feature that the plasma generation process by the ion source 101 can be controlled independently. However, the RF ion source 101
, It is difficult to make the ion current density distribution uniform, and it is difficult to evenly form an electron beam evaporation source on a large area sample substrate, and it is difficult to make the area large.

FIG. 14 shows a schematic diagram of the ion beam sputtering method. The ion beam sputtering apparatus 113 includes an RF ion source called a deposition gun (sputter gun) 114, rotary targets 116 117 and 118 for attaching an oxide target, a substrate holder, and an RF ion source called an assist gun 115 in a vacuum chamber. Are arranged. Oxygen ions and argon ions (ion beam 121) plasmatized in the deposition gun 114 are used as a target A116, a target B117, and a target C11.
When a target of 8 is irradiated with the target, the target material is sputtered, and the sputtered particles are
A stream of sputter material 120 is formed and deposited on the substrate. In addition, the assist gun 115 promotes vapor deposition of the material attached on the substrate. This sputtering method can form a film having a good film quality, but since an oxide is used as the target material, the film forming rate is extremely slow, and the film forming time is significantly longer than 40 hours.

Some of the film forming methods described above are different from each other because of the vapor deposition method using the RF plasma source as the plasma source.
Stable plasma cannot be obtained unless the gas pressure is about 1 Pa or higher. If the pressure in the chamber is high, it is difficult to improve the quality of the film because impurities are mixed into the film and dust is likely to be generated.In addition, the film formation monitor and control are measured by a crystal oscillator film thickness meter. Therefore, since the film thickness on the substrate is not directly observed and controlled, if the number of layers of the multilayer film increases, it becomes impossible to monitor it, and therefore a periodic sample exchange mechanism is required.

For the purpose of improving the quality of the sputtered film, electron cyclotron resonance (Electron C
irradiating a substrate with a plasma stream created by using synchrotron resonance (ECR) and a divergent magnetic field,
At the same time, a high-frequency voltage or a direct-current voltage is applied between the target and the ground, and the ions in the plasma flow generated by the ECR are attracted to the target to collide with each other to cause a sputtering phenomenon and deposit a film on the substrate. (Hereinafter, this is referred to as an ECR sputtering method). The characteristics of the ECR sputtering method are, for example, Ono et al., Japanese Journal of Applied Physics, Volume 23, Volume 8
No., L534, 1984 (Jpn. J. Appl.
Phys. 23, no. 8 L534 (1984). )
(Reference 1).

According to the ECR sputtering method, stable ECR plasma can be obtained at a gas pressure in the molecular flow region of about 0.01 Pa or less. In addition, by high frequency or DC voltage, ECR
Since the ions generated by the method are applied to the target to perform the sputtering, the sputtering can be performed at a low pressure.

Further, the substrate is exposed to the ECR plasma stream along with the sputtered particles. Ions in the ECR plasma flow are 10 eV to several tens of e due to the divergent magnetic field.
Controlled to V energy. Further, since the plasma is generated and transported at a low pressure at which the gas behaves as a molecular flow, the ion current density of the ions reaching the substrate can be large. Therefore, the ions in the ECR plasma stream are
Energy is given to the raw material particles that are sputtered and fly to the substrate, and the bonding reaction between the raw material particles and oxygen or nitrogen is promoted, so that the film quality is improved.

In particular, it is characterized in that a high quality film can be formed at a low substrate temperature close to room temperature without heating from the outside. The high-quality thin film formed by the ECR sputtering method is described in, for example, Amazawa et al., Journal Off Vacuum Science and Technology, Volume B17, No. 5, page 2222, 1999 (J. Vac. Sci.
Technol. B17, no. 5,2222 (199
9). ) (Reference 2).

Further, the surface morphology of the film formed by the ECR sputtering method is flat on the order of atomic scale. Therefore, the ECR sputtering method is a promising apparatus / method for forming a multilayer film having an interface on the order of nanometers.

Further, in Japanese Patent No. 3208439, "Plasma generating means for introducing a plasma generating gas to generate a plasma flow by plasma, and a film arranged concentrically with the plasma flow so as to be in contact with the plasma flow Irradiated by a target made of a forming material, a means for scattering the particles of the film forming material from the target into the plasma flow by using the ions of the plasma flow, and a plasma flow making the particles of the film forming material fly In a film forming plasma apparatus having a substrate mounting table on which a film forming sample substrate is mounted and fixed, the target has a cylindrical shape, the substrate mounting table is arranged on the rotational symmetry axis of the target, and The center of rotation is tilted with respect to the axis of rotational symmetry of the target, and a film is formed at the intersection of the axis of rotational symmetry of the target and the axis of rotation of the substrate mounting table. By providing the rotating means for rotating the sample substrate so as to be tilted so as to be positioned in the direction opposite to the target, the rotating substrate can be tilted with respect to the ECR plasma source. It is described that the uniformity of can be improved.

[0026]

However, since only one ECR sputtering source with a target is disposed in the vacuum chamber, it is necessary to deposit a plurality of materials such as a multilayer film. , It was necessary to prepare a plurality of ECR sputtering sources and a substrate sample stand having the same number of substrate holding mechanisms as that. For example, when two ECR sputtering sources and the same number of rotating substrate sample stands are prepared to form a multilayer film, the following procedure is required. First, in order to form a film using the target (A) as a raw material, the sample substrate is conveyed and moved, placed and fixed, and the sample substrate is tilted and rotated to form a film. After forming a film using the target (A) as a raw material, the rotation of the sample substrate is stopped and the tilt is restored. Next, in order to form a film using the target (B) as a raw material, the sample substrate is conveyed and moved, placed and fixed,
The sample substrate is tilted and rotated to form a film. After forming a film using the target (B) as a raw material, the rotation of the sample substrate is stopped and the tilt is restored. Next, the thin film using the target (A) as a raw material is formed by carrying and moving the sample substrate, and the thin film using the target (B) as a raw material is formed by carrying out the same procedure by carrying the same. Hereafter, it was necessary to repeat the same procedure. Therefore, there is a problem that the film formation time becomes long.

Furthermore, a plurality of ECR ion sources are prepared,
Since it is necessary to prepare the same number of substrate sample stands for tilting and rotating, there is a problem that the apparatus itself becomes large-scale and complicated and becomes expensive.

Therefore, the present invention has been made to solve the above-mentioned problems and problems of the prior art,
An object thereof is to provide a thin film forming apparatus capable of forming a plurality of film forming materials in a single vacuum chamber with high uniformity and at high speed and forming a high quality thin film.

[0029]

In order to achieve such an object, the present invention provides a vacuum container and a plasma generating means for introducing a plasma generating gas into the vacuum container to generate a plasma flow by plasma. A plurality of targets provided with a film-forming material arranged concentrically with the plasma flow so as to come into contact with the plasma flow, and a means for scattering the particles of the film-forming material from the target by sputtering using the ions of the plasma flow. In the thin film forming apparatus having the sputtering source and the substrate sample stand for mounting and fixing the film forming sample substrate irradiated by the plasma flow in which the particles of the film forming material are scattered, the plasma generating means is an electron cyclotron. A plasma is generated by resonance discharge, and the rotational symmetry axis of the target of multiple sputtering sources is on the central axis of rotation of the substrate sample stage. They are arranged so as to intersect with each other and incline with respect to the rotation center axis of the rotating sample stage. Rotating means for rotating while tilting so as to be positioned in the opposite direction of the target,
And a moving means for moving the substrate sample base up and down. According to the present invention, it is possible to form a multi-layer film using a plurality of target materials as raw materials under optimum conditions with only one substrate sample stage without moving the substrates alternately. Further, the thin film forming apparatus of the present invention, on the substrate sample stage,
It is characterized in that it comprises a bias applying means for applying a bias. According to the present invention, it is possible to adjust the energy of ions that enter the substrate. Further, the thin film forming apparatus of the present invention is characterized in that a magnetic coil is provided on the side of the substrate sample base opposite to the side on which the film forming sample substrate is mounted and fixed. According to the present invention, the degree of divergence of the divergent magnetic field generated by the magnetic coil of the ECR sputtering source can be controlled. Further, the thin film forming apparatus of the present invention includes a light source, a light projecting unit for irradiating the film forming sample substrate with light from the light source, a light receiving unit for receiving light transmitted through the film forming sample substrate, and a light receiving unit. And a measuring unit that measures the emitted light as a spectral spectrum. According to the present invention, the film thickness can be directly monitored. Further, the thin film forming apparatus of the present invention includes a light source, a light projecting unit that irradiates the light from the light source onto the film forming sample substrate, a light receiving unit that receives the light reflected from the film forming sample substrate, and a light receiving unit. And a measuring unit that measures the emitted light as a spectral spectrum. According to the present invention, the film thickness can be directly monitored.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are given to those having the same function, and the repeated description thereof will be omitted. In addition, 1 Pa = 0.0076 Torr, 1 T = 10000
Gauss, the unit sccm indicating the gas flow rate is 0 ° C.,
It shows that a fluid of 1 atm flows 1 cm ^{3 in} 1 minute, and the one converted into nitrogen gas is used.

As shown in FIG. 1, the thin film forming apparatus according to the first embodiment is constructed by using two ECR sputtering sources. That is, two ECRs are provided in the sample chamber (vacuum chamber) in which the substrate sample stand 10 for holding the sample is installed.
This is a device to which the sputtering sources 3 and 4 are connected. The two ECR sputtering sources 3 and 4 are arranged symmetrically with respect to the radiation of the sample substrate 11. In FIG. 1, 2 is a waveguide, 3 is a first ECR plasma source, and 4 is a second ECR plasma source.
Plasma source, 5 and 6 magnetic coils, 7 quartz introduction window, 8
Is a target, 9 is high-frequency power, 10 is a substrate sample stage, 1
Reference numeral 1 is a sample substrate, 12 is a plasma flow, and 13 is a plasma flow.

Molecular beam epitaxy (Molecular)
Also in Beam Epitaxy (MBE) and the like, in order to irradiate a plurality of materials on a sample substrate, a plurality of evaporation sources for irradiating the materials are installed to form a film. In this case, each evaporation source is arranged to be inclined with respect to the normal line of the sample substrate due to physical restrictions. For example, in a vaporization source of a type that radiates a raw material from a single point like a crucible, it is difficult to secure the uniformity of a film on a large-area wafer because the distribution of radiant particles is greatly different between the center and the periphery.

On the other hand, in the thin film forming apparatus 1 according to the first embodiment, a circular or polygonal ring-shaped target is arranged so as to surround the plasma streams 12 and 13. Therefore, the raw material supply source viewed from the sample substrate 11 is not simply one, and can be regarded as a circular raw material supply source that reflects the target shape. In this case, Patent No. 320
As disclosed in Japanese Patent No. 8439, even if the target and the sample substrate 11 are arranged so as to face each other, it is difficult to ensure the uniformity of the film. Therefore, by tilting and rotating the sample substrate 11, a large area wafer can be obtained. It is possible to secure the uniformity.

However, in order to form a multilayer film, it is necessary to use a plurality of film forming materials having different properties and characteristics as targets. Different film forming materials have different sputtering rates. Therefore, when different film forming materials are formed on the sample substrate at the same distance by using the ECR plasma source having the same inclination, the film formed is different. The uniformity is different. Therefore, in order to form a uniform film by uniform sputtering, it is necessary to form the film at an optimum tilt angle according to the target material. When a plurality of ECR sputtering sources are connected to the vacuum chamber by changing the tilt angle in order to obtain the optimum uniformity according to the target material, they are connected at the angle peculiar to the target material. It is impractical because it reduces versatility and adds complexity to device design. That is, when the ECR sputtering source is attached to the vacuum chamber with a predetermined inclination, even if a uniform film can be deposited on one film forming material, the uniformity cannot be obtained on the other film forming material. Expected to deteriorate.

Therefore, in the first embodiment, in order to improve the uniformity of each film in the structure in which the two ECR sputtering sources 3 and 4 are arranged symmetrically with respect to the radiation line of the sample substrate 11, The substrate sample stage 10 is moved up and down according to the target material. By doing so, the sample substrate 11 can be moved to the optimum position for film formation, so that even if the sputtering material is different, high-quality film formation is maintained and a uniform ultra-thin multilayer film is formed. Can be formed.

Next, the principle of the thin film forming apparatus 1 according to the first embodiment will be described. In FIG. 2, A1 is a rotational symmetry axis of the rotationally symmetric first target 8-1, A2 is a rotational symmetry axis of the rotationally symmetric second target 8-2, B is a rotation center axis around which the sample substrate 11 rotates, and C is A coordinate axis passing through the rotation center axis B of the sample substrate 11 on the thin film formation plane of the sample substrate 11, C ^* is a coordinate axis when the sample substrate 11 is moved upward. P is the intersection of the rotational symmetry axis A1 of the first target 8-1, the rotational symmetry axis A2 of the second target 8-2, and the rotation center axis B of the sample substrate 11, and Q is the rotation center axis B of the sample substrate 11. And the intersection of the thin film formation surface of the sample substrate 11, Q ^*
Is the intersection of the rotation center axis B of the sample substrate 11 and the thin film formation surface of the sample substrate 11 when the sample substrate 11 is moved upward, R
1 is the intersection of the rotational symmetry axis A1 of the first target 8-1 and the thin film formation surface of the sample substrate 11, and R2 is the second target 8-.
The intersection of the rotational symmetry axis A2 of 2 and the thin film formation surface of the sample substrate 11, R1 ^* is the first when the sample substrate 11 is moved upward.
The intersection point of the rotational symmetry axis A1 of the target 8-1 and the thin film forming surface of the sample substrate 11, R2 ^* is the rotational symmetry axis A2 of the second target 8-2 and the sample substrate 11 when the sample substrate 11 is moved upward. It is the intersection with the thin film formation surface.

Further, θ is the rotation center axis B of the sample substrate 11
Seen first target 8-1 and second target 8-
2 tilt angle, that is, the rotation pair of the first target 8-1
The angle between the nominal axis A1 and the rotation center axis B of the sample substrate 11
Yes, the rotational symmetry axis A2 of the second target 8-2 and the sample base
It is an angle formed by the central axis B of rotation of the plate 11. Also, S1
Is from the intersection point Q to the rotational symmetry axis A1 of the first target A1.
The dropped perpendicular, S2, is the time of the second target A2 from the intersection Q.
Perpendicular line drawn on axis of symmetry A2, S1 ^*Is the sample substrate 11
Intersection Q when moving to the top^*To the first target 8-
The perpendicular line drawn to the rotational symmetry axis A1 of 1, S2^*Is the sample substrate
Intersection Q when 11 moves to the top^*From the second target
8-2 is a vertical line drawn on the rotational symmetry axis A2 of 8-2. Well
Also, T1 is spatter scattered from the first target 8-1.
The particles, T2, are spatters scattered from the second target 8-2.
It is a particle. The rotational symmetry axes A1 and A2, the center of rotation
Axis B, coordinate axes C and C^*Are in the same plane.

In the above structure, the first target 8-1
Sputtered particles T1 scattered from the second target 8-2
The sputtered particles T2 scattered from are scattered in the direction of the sample substrate 11 without being scattered at the degree of vacuum when forming a film, for example, on the order of 0.01 Pa. Therefore, the density of the sputtered particles T1 and T2 on the sample substrate 11 is inversely proportional to the square of the distance from the sputtering point of the first target 8-1 and the second target 8-2. The thickness of the film formed at a point on the sample substrate 11 corresponds to the integral of the sputtered particle density from the target that can be expected from that point. For this reason, when the target is not tilted (that is, θ = 0 degree), the film thickness is thick in the central region of the sample substrate 11 and thin in the peripheral region, so that a high uniformity cannot be obtained.

First, when the thin film formation plane is on the C-axis,
1st in the plane including A1 and A2, B, C centering on the intersection point P
By inclining the target 8-1 and the second target 8-2, the positions where the supply amounts of the sputtered particles T1 and T2 are the largest are set to R1 and R2 apart from Q, and further, the sample substrate 11 is rotated. By forming the film, the uniformity of the formed film can be improved when viewed on a time average basis.

However, the first target 8-1 and the second target 8-1
If the film forming materials of Get 8-2 are different, the spatter
The film ratio is different, so the film can be formed only by the above tilt and rotation.
The uniformity of the film cannot be improved. So target 8
Depending on the film forming material, the thin film forming plane from the C axis to C^*
Move to axis. That is, the rotational symmetry axis of the sample substrate 11
B axis stays at points Q to Q^*Move up and down. To do so
And the distance between point Q and point S1 and point Q and point S2
Is the point Q^*And point S1^*Distance to and point Q ^*And point S
Two^*Since it can be changed to the distance at the same time,
The film forming materials of the target 8 having different
It is possible to keep the uniformity of the film high.

In addition, the first ECR plasma source 3 and the second ECR plasma source 4 used in the thin film forming apparatus 1 according to the first embodiment temporarily branch the introduced microwave power to generate a plasma source. The particles are re-bonded immediately before, and the running time can be greatly improved by preventing the particles scattered from the target 8 from adhering to the quartz introduction window 7.

Next, the thin film formation by the first target 8-1 will be described. In FIG. 3, magnetic lines of force are formed by the magnetic coils 5 and 6 of the first ECR plasma source 3,
The lines of magnetic force form a divergent magnetic field and spread toward the sample substrate. Due to this divergent magnetic field, the plasma generated by the first ECR plasma source 3 is transported as a plasma stream 12 toward the sample substrate. Further, regarding the thin film formation by the second target 8-2, as shown in FIG. 4, magnetic lines of force are formed by the magnetic coils 5 and 6 of the second ECR plasma source 4, and the magnetic lines of force form a divergent magnetic field, Spread in the board direction.
Due to this divergent magnetic field, the plasma generated by the second ECR plasma source 4 is transported as a plasma flow 13 toward the sample substrate. In film formation, the substrate sample stage 10 is moved up and down according to the film forming material of the target 8 to adjust the position to an optimum position for film formation.

Next, a method for forming a multilayer film using the thin film forming apparatus 1 according to the first embodiment will be described. First, the substrate sample table 1 on which the sample substrate 11 is mounted and fixed
0 is rotated at the optimum position in the film forming material of the first target 8-1. A first thin film is formed on the sample substrate 11 by sputtering the ring-shaped first target 8-1. After forming the film to a desired film thickness, the sputtering for forming the first thin film is ended, and the substrate sample stage 10 is rotated at the optimum position in the film forming material of the second target 8-2. The ring-shaped second target 8-2 is sputtered to form a second thin film on the same sample substrate 11. After forming the film to a desired film thickness, the sputtering for forming the second thin film is completed. After that, the first target 8-
1 and the second target 8-2 are sputtered to form a multilayer film.

For example, the first target 8-1 has a first medium such as pure aluminum, the second target 8-2 has a second medium such as pure silicon, a reactive gas such as oxygen gas, and an inert gas. The formation of a multilayer film of an alumina thin film and a silicon dioxide thin film using, for example, argon will be described. Here, the tilt angle θ of the first target 8-1 and the second target 8-2 viewed from the rotation center axis B of the sample substrate 11 was set to 23 degrees. ECR
Argon was introduced into the plasma sources 3 and 4 so as to stably obtain plasma regardless of the amount of the reactive gas supplied. FIG. 5 shows typical characteristics of the oxygen gas flow rate dependency of the deposition rate and the refractive index of the alumina film formed on the sample substrate 11 under these conditions. Also, set the argon gas flow rate to 2
0 sccm, oxygen gas flow rate from 0 to 10 sccm, EC
The microwave power to be introduced into the R plasma sources 3 and 4 is 500
W, the high frequency power 9 applied to the target was 500 W, and the sample substrate 11 was not heated. The refractive index is 6
The measurement was performed using an ellipsometer with a 38 nm laser.

As shown in FIG. 5, the first target 8-1
The deposition rate of the alumina formed by the method increases with the increase of the oxygen flow rate, and then gradually decreases to the maximum at about 4 sccm, and the oxygen gas flow rate is 7 sccm.
It rapidly decreases in the vicinity and settles at a small deposition rate of about 1/10 of the maximum value. The reason that the deposition rate sharply decreases when the oxygen gas flow rate is around 7 sccm is that the rate of oxidation of aluminum on the target surface increases and the alumina has a smaller sputtering rate than aluminum.
The larger the sputter rate, the faster the deposition rate. Therefore, if the target surface is less likely to be sputtered and the sputter rate decreases, the deposition rate also slows down. This phenomenon is a phenomenon that is widely known in the reactive sputtering method.
Yuu Kanehara, "Sputtering Phenomenon", The University of Tokyo Press,
120 to 132 (Reference 3).

The refractive index of the alumina film sharply decreases at a certain oxygen gas flow rate as the oxygen flow rate increases, and becomes the refractive index of the sapphire substrate satisfying the stoichiometric composition. From this result, it is understood that the refractive index can be controlled by the reactive gas while maintaining a good film quality. By controlling the flow rate of the oxygen gas to be supplied, the refractive index is 1.6
It can be controlled in the range of 1 to 4.3.

FIG. 6 shows the uniformity of the deposited film thickness and the refractive index during the film formation of alumina on the 8-inch wafer surface. Also here, the first target 8-1 viewed from the rotation center axis B of the sample substrate 11
And the inclination angle θ of the second target 8-2 was set to 23 degrees. FIG. 6 shows the in-plane distance dependence of the deposited film thickness of the alumina film and the refractive index of the alumina film from the center of the sample substrate with the distance between the points P and Q as a parameter. It can be seen from FIG. 6 that the refractive index hardly changes even if the distance between the points P and Q is changed. However, as the distance from the point P to the point Q increases, the deposited film thickness increases and the uniformity thereof also changes.
From this result, it is understood that the optimum sample substrate position exists, and the uniformity of the formed film can be controlled by changing the sample substrate position. Similarly, for silicon dioxide, the uniformity can be controlled by the distance between the sample substrate 11 and the target, and there is a distance where the uniformity of the formed film is the best.

By the above method, the first target 8-
By using alumina for 1 and pure silicon for the second target 8-2 and alternately depositing alumina and silicon dioxide, a multilayer film can be formed as shown in FIG. Further, when a multilayer film is formed by the multilayer film forming method, it is not necessary to transfer the wafer every time one layer is deposited, and only the sample substrate 11 is moved up and down to uniformly form a thin film made of different film forming materials. You can Therefore, the film formation time can be significantly shortened and the apparatus can be made more compact.

The thin film forming apparatus according to the second embodiment, as shown in FIG. 8, has a bias applying means 1 for applying a bias to the substrate sample stage 10 of the thin film forming apparatus 1 of the first embodiment.
6 is provided. By doing so, the energy of the ions incident on the sample substrate 11 can be adjusted, so that the film quality can be improved and the uniformity can be controlled.

The thin film forming apparatus according to the third embodiment, as shown in FIG. 9, is provided on the side opposite to the side on which the sample substrate 11 of the substrate sample base 10 of the thin film forming apparatus 1 of the first embodiment is mounted and fixed. An auxiliary coil is installed. By doing so, it is possible to further improve the uniformity of film formation by controlling the divergence of the divergent magnetic field generated by the main magnetic coils 5 and 6.

As shown in FIG. 10, the thin film forming apparatus according to the fourth embodiment is different from the thin film forming apparatus 1 of the first embodiment in that
A light source 18 for projecting light onto the sample substrate 11, and a light source 1
8 and a light projecting section 19 for projecting light from the light source 18 onto the sample substrate 11, and the sample substrate 1
1, a light receiving unit 20 including an optical fiber for guiding the light from the light projecting unit 19 to the spectroscope 21, and the light receiving unit 20 is connected by, for example, an optical fiber, and the light received by the light receiving unit 20 is used as a spectral spectrum. Spectrometer 21 for photometry and spectroscope 2
1 is connected to 1 by an optical fiber, for example, and an arithmetic unit 22 for calculating an extreme value with respect to the wavelength of the spectrum is installed. By doing so, the sample substrate 11
It is possible to directly monitor the state of film formation in (1) by transmitted light.

As shown in FIG. 11, the thin film forming apparatus according to the fifth embodiment is different from the thin film forming apparatus 1 of the first embodiment in that
A light source 18 for projecting light onto the sample substrate 11, and a light source 1
8 is connected by, for example, an optical fiber, projects the light from the light source 18 onto the sample substrate 11, and projects the reflected light from the sample substrate 11 to the half mirror 24, and the light from the light source 18. The sample substrate 11 is guided to the light receiving unit 23.
The half mirror 24 that guides the reflected light from the mirror 21 to the spectroscope 21 is connected to the half mirror 24 by an optical fiber, for example, and the spectroscope 21 that measures the light from the half mirror 24 as a spectral spectrum is connected to the spectroscope 21 by an optical fiber, for example. The calculation unit 22 for calculating an extreme value with respect to the wavelength of the spectrum is installed. By doing so, even when the sample substrate 11 is an opaque substrate, the film formation state can be directly monitored by reflected light.

Further, in the first to fifth embodiments, the ECR plasma source 25 is provided in the vacuum chamber as shown in FIG.
As shown in (a), the case of two units has been described.
As shown in FIGS. 12B to 12E, three or more ECR sources 25 can be installed. By doing so, thin films made of three or more different film forming materials can be formed on the sample substrate 11. In the case of FIG. 12 (b) having three units, FIG. 12 (c) having four units, and FIG. 12 (d) having five units,
FIG. 12E shows the case of 6 units.

In any case, the ECR sputter source 2
The rotation target axis of 5 is on a concentric circle centered on the rotation center axis B of the sample substrate 11. By doing so, even if the number of ECR sputtering sources 25 in which the targets 7 are arranged increases, by moving the position of the sample substrate 11 up and down, film formation according to different film forming materials can be performed, and film formation can be performed. The uniformity of the film is improved.

[0055]

According to the present invention, in one vacuum chamber, the particles of the film forming material from the plurality of ECR sputtering sources have a predetermined inclination angle with respect to the sample substrate. And the vertical movement means is provided on the substrate sample base, it is possible to form a multilayer film using a plurality of target materials as a raw material more uniformly and at high speed without alternately moving the sample substrates. Furthermore, the film thickness can be directly monitored, and a highly accurate multilayer film can be formed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a thin film forming apparatus according to a first embodiment.

FIG. 2 is a diagram for explaining the principle of the thin film forming apparatus according to the first embodiment.

FIG. 3 is a diagram for explaining thin film formation by the first ECR sputtering source of the thin film forming apparatus according to the first embodiment.

FIG. 4 is a diagram for explaining thin film formation by a second ECR sputtering source of the thin film forming apparatus according to the first embodiment.

FIG. 5 is a diagram showing sputtering characteristics of the thin film forming apparatus according to the first embodiment.

FIG. 6 is a diagram showing film forming characteristics of the thin film forming apparatus according to the first embodiment.

FIG. 7 is a cross-sectional view showing the structure of a multilayer film manufactured by using the thin film forming apparatus according to the first embodiment.

FIG. 8 is a schematic configuration diagram of a thin film forming apparatus according to a second embodiment.

FIG. 9 is a schematic configuration diagram of a thin film forming apparatus according to a third embodiment.

FIG. 10 is a schematic configuration diagram of a thin film forming apparatus according to a fourth embodiment.

FIG. 11 is a schematic configuration diagram of a thin film forming apparatus according to a fifth embodiment.

FIG. 12 is a diagram for explaining the arrangement of ECR sputtering sources in the thin film forming apparatus according to the embodiment.

FIG. 13 is a schematic configuration diagram for explaining a conventional multilayer film device.

FIG. 14 is a schematic configuration diagram for explaining another conventional multilayer film device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thin film forming apparatus, 2 ... Waveguide, 3 ... 1st ECR plasma source, 4 ... 2nd ECR plasma source, 5 ... Magnetic coil, 6 ... Magnetic coil, 7 ... Quartz introduction window, 8 ... Target, 8-1 ... First target, 8-2 ... Second target, 9 ... High frequency power, 10 ... Substrate sample stage, 11 ... Sample substrate, 12 ... Plasma flow, 13 ... Plasma flow, 14 ... First
Medium layer, 15 ... Second medium layer, 16 ... Bias applying means, 17 ... Auxiliary coil, 18 ... Light source, 19 ... Projector, 2
0 ... Light receiving part, 21 ... Spectrometer, 22 ... Arithmetic part, 23 ... Emitting light receiving part, 24 ... Half mirror, 25 ... Plasma source, 100
… Ion-assisted vapor deposition equipment, 101… RF ion source, 1
02 ... Electron beam evaporation source A, 103 ... EB source target A, 104 ... Electron beam evaporation source B, 105 ... EB source target B, 106 ... Film thickness meter, 107 ... Substrate, 1
08 ... Sample stage, 109 ... Rotation mechanism, 110 ... Ion flow,
111 ... Sputtering raw material A, 112 ... Sputtering raw material B, 1
13 ... Ion beam sputtering apparatus, 114 ... Deposition gun, 115 ... Assist gun, 116 ... Target A, 1
17 ... Target B, 118 ... Target C, 119 ...
Plasma flow, 120 ... Sputtering material, 121 ... Ion beam.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaru Shimada             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Seitaro Matsuo             4-16-30 Shimorenjaku, Mitaka City, Tokyo             Inside Nutty Afty Co., Ltd. (72) Inventor Toshiro Ono             4-16-30 Shimorenjaku, Mitaka City, Tokyo             Inside Nutty Afty Co., Ltd. F term (reference) 4K029 CA13 CA15 DC16 DC48 EA00                       EA01 JA01                 5F058 BA06 BC03 BD05 BF14 BJ01

Claims (5)

[Claims] 1. A vacuum container, a plasma generating means for introducing a plasma generating gas into the vacuum container to generate a plasma flow of plasma, and a concentric arrangement with the plasma flow so as to be in contact with the plasma flow. Formed of a film forming material, a plurality of sputtering sources having means for scattering the particles of the film forming material from the target by sputtering using the ions of the plasma flow, and particles of the film forming material In a thin film forming apparatus having a substrate sample stand for mounting and fixing a film forming sample substrate irradiated by the plasma flow that is scattering, the plasma generating means generates plasma by electron cyclotron resonance discharge, The plurality of sputtering sources are arranged such that the rotational symmetry axis of the target intersects with the rotational center axis of the substrate sample stage. The substrate sample stage is arranged so as to be inclined with respect to the rotation center axis of the rotating sample stage, and the substrate sample stage has an intersection point between the rotational symmetry axis of the target and the rotation center axis of the substrate sample stage for the film formation. A thin film forming apparatus comprising: a rotating unit that rotates while tilting the sample substrate so as to be positioned in a direction opposite to the target, and a moving unit that vertically moves the substrate sample stage. 2. The thin film forming apparatus according to claim 1, wherein the substrate sample stage is provided with bias applying means for applying a bias. 3. The thin film forming apparatus according to claim 1, further comprising a magnetic coil on a side of the substrate sample base opposite to a side on which the film forming sample substrate is mounted and fixed. . 4. The thin film forming apparatus according to claim 1, a light source, a light projecting unit that irradiates the film forming sample substrate with light from the light source, and the film forming sample substrate. A thin film forming apparatus comprising: a light receiving unit that receives the light that has passed through; and a measuring unit that measures the light received by the light receiving unit as a spectral spectrum. 5. The thin film forming apparatus according to claim 1, a light source, a light projecting unit that irradiates the film forming sample substrate with light from the light source, and the film forming sample substrate. A thin film forming apparatus comprising: a light receiving unit that receives light reflected by the light receiving unit; and a measuring unit that measures the light received by the light receiving unit as a spectrum.