JP4167749B2 - Sputtering method and sputtering apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of the present application is sputtering that creates a predetermined thin film on the surface of a substrate by sputtering.Method andSputtering suitable for film formation on the inner surface of minute holes formed on the surface of the substrateMethod andIt relates to the device.
[0002]
[Prior art]
In the manufacturing process of semiconductor devices such as various memories and logics, a sputtering method is frequently used for forming a conductive film for wiring and a barrier film for preventing mutual diffusion of different layers. Although there are various characteristics required for the sputtering process, it has recently been strongly demanded that the inner surface of the hole formed on the surface of the substrate can be coated with a thin film having a sufficient thickness.
Specifically, in the manufacture of many semiconductor devices having an FET structure, a contact hole is provided in an insulating layer formed on the upper side of a channel, and the contact hole is filled with a conductive film to form a channel wiring. ing. In such a channel wiring formation process, a barrier film is formed on the inner surface (bottom surface and side surface) of the contact hole in order to prevent mutual diffusion between the wiring conductive film and the underlying channel. In manufacturing a device having a multilayer wiring structure, a similar barrier film may be provided on the inner surface of an interlayer wiring through hole to prevent interdiffusion between the interlayer wiring and the underlying wiring layer.
Such contact holes and through holes tend to have higher aspect ratios against the backdrop of higher integration and higher functionality of devices. The aspect ratio is the ratio of the depth of the hole to the diameter or width of the hole opening. Sputtering is a technique in which particles of the target material (hereinafter, sputtered particles) are released from the target by sputtering the target, and the sputtered particles reach the surface of the object to form a film, but the aspect ratio is high. Then, it becomes difficult to make the sputtered particles reach the inner surface of the hole. As a result, film formation on the inner surface of the hole becomes insufficient.
[0003]
As an index of film formation on the inner surface of a minute hole such as a contact hole or a through hole, there is an index called a bottom coverage rate. The bottom coverage ratio is a ratio of the film formation rate on the bottom surface of the hole to the film formation rate on the surface around the hole (surface outside the hole). As described above, high-aspect-ratio holes have a problem in that the bottom coverage rate decreases because the sputtered particles do not sufficiently reach the bottom surface of the holes. When the bottom coverage ratio is lowered, in the case of a barrier film, the barrier film becomes thin on the bottom surface of the hole, which may cause a fatal defect in device characteristics such as a junction leak.
As a sputtering technique for improving the bottom coverage rate, an ionized sputtering technique has been put into practical use. In ionized sputtering, sputtered particles emitted from the target are ionized and an electric field in the depth direction of the hole is set, and ionized sputtered particles (hereinafter referred to as ionized sputtered particles) are guided perpendicularly to the substrate by the electric field and enter the hole. It is a technique to reach. In ionized sputtering, ionized sputtered particles fly perpendicularly to the substrate and are incident on the substrate, so that there is an advantage that film formation with a high bottom coverage rate can be achieved.
[0004]
[Problems to be solved by the invention]
However, the aspect ratio of holes has been increasing due to the increasing integration of devices. For this reason, it is expected that there is a limit to the ionization sputtering method.
In other words, taking a DRAM (an occasional read / write type memory that requires a memory holding operation) as an example, mass production of a 64 megabit class DRAM is about to start in earnest. In the 64 megabit class, the circuit line width is around 0.25 microns and the contact hole aspect ratio is about 4-5. With holes of this level, a bottom coverage rate of about 15% can be obtained even by the ionized sputtering described above, and it is considered that mass production is possible.
However, in a device having a line width of 0.18 to 0.13 microns, which is called a next generation device, the aspect ratio is expected to reach about 7 to 10. It is considered that a hole with an aspect ratio increased to this level cannot be formed with a sufficient bottom coverage by the ionization sputtering, and a technical breakthrough is necessary.
[0005]
This point will be described more specifically with reference to FIG. FIG. 6 is a diagram illustrating the technical difficulty of film formation for a high aspect ratio hole. FIG. 6 shows a schematic cross-sectional view of a substrate 9 having holes with an aspect ratio of 10 as an example of a substrate used for manufacturing a next-generation device.
When the above-described conventional ionization sputtering method is used for film formation in the hole 90 shown in FIG. 6, the bottom coverage rate is insufficient under the same conditions as in the prior art, and practical application is difficult. Considering the extension line of conventional ionization sputtering, the ionization efficiency of sputtered particles is improved, and the strength of the electric field that leads to ionized sputtered particles is increased to some extent, and in terms of bottom coverage rate There is a possibility that it can respond to mass production.
[0006]
However, according to the inventor's study, it has been found that if such improvements are made, the problem of a decrease in the side coverage ratio occurs, which becomes a new obstacle to mass production. The side coverage ratio is the ratio of the film formation rate on the side surface 91 of the hole 90 to the surface outside the hole 90.
More specifically, when ionization is performed by improving ionization efficiency to ionize more sputtered particles, increasing the electric field strength and flying more ionized sputtered particles in the depth direction of the hole, Most of the sputtered particles incident on the substrate 9 fly in the depth direction of the hole 90. As a result, even when entering the hole 90, most of the sputtered particles reach the bottom surface 92 of the hole 90 and hardly reach the side surface 91 of the hole 90. For this reason, the film-forming speed | rate to the side surface 91 of the hole 90 will fall extremely. In the case of a barrier film, it is considered that about 20% is necessary not only for the bottom coverage rate but also for the side coverage rate, but it is difficult to achieve this on the extension line of the conventional ionization sputtering described above. Is considered necessary.
[0007]
The invention of the present application has been made to solve the above-mentioned problems. In view of the next generation device having a line width of 0.18 microns or less, the bottom coverage ratio for holes having a high aspect ratio of 7 or more. In addition to this, a breakthrough is proposed in which a film having a sufficiently high side coverage ratio can be formed.
[0008]
[Means for Solving the Problems]
  In order to solve the above problem, the invention according to claim 1 of the present application is a sputtering method for forming a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
  While ionizing sputtered particles emitted from the target,Setting electric field with component in the depth direction of the holeOperating the electric field setting meansIonized sputtered particlesBy electric field setting meansSputtering is performed by increasing the distance between the target and the substrate and lowering the pressure as compared with the bottom surface film forming step in which the film forming rate on the bottom surface of the hole is increased by accelerating with an electric field. Including a side surface film forming step for increasing the film formation rate on the side surface of the hole, and the bottom surface film forming step and the side surface film forming step are continuously performed in a vacuum.Is the way
  The side surface film forming step is a step performed without electric field setting by the electric field setting means.It has the structure of.
  In order to solve the above problem, the invention according to claim 2 is the configuration of claim 1,The pressure in the bottom surface deposition step is in the range of 10 mTorr to 100 mTorr, the pressure in the side surface deposition step is 1 mTorr or less, and the distance between the target and the substrate in the bottom surface deposition step is the maximum width of the substrate The distance between the target and the substrate in the side surface film forming step is a distance within the range of 1 to 1.5 times the maximum width of the substrate.It has the structure of.
  In order to solve the above-mentioned problem, the invention according to claim 3 is the configuration according to claim 1 or 2, wherein in the bottom surface film forming step, high-frequency voltage is applied to the target to perform sputtering, and the side surface film formation is performed. In the process, sputtering is performed by applying a negative DC voltage to the target.It has the structure of.
  In order to solve the above problems, the invention according to claim 4 is the structure according to any one of claims 1 to 3, wherein the auxiliary electrode provided separately from the target is insulated from the ground potential or the auxiliary electrode. In this method, the sputtered particles are ionized by applying a high-frequency voltage to the auxiliary electrode, and the auxiliary electrode has a cylindrical shape surrounding the sputtered particle flying space between the target and the substrate.
  In order to solve the above problem, the invention according to claim 5 is a sputtering method for creating a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
The sputtered particles emitted from the target are ionized, and an electric field having a component in the depth direction of the hole is set, and the ionized sputtered particles are accelerated by this electric field to increase the deposition rate on the bottom surface of the hole. A bottom film forming step, and a side film forming process for increasing the film forming rate on the side surface of the hole by increasing the distance between the target and the substrate and lowering the pressure as compared with the bottom film forming process. , The bottom film forming step and the side film forming step are continuously performed in a vacuum,
The pressure in the bottom surface deposition step is in the range of 10 mTorr to 100 mTorr, the pressure in the side surface deposition step is 1 mTorr or less, and the distance between the target and the substrate in the bottom surface deposition step is the maximum width of the substrate The distance between the target and the substrate in the side surface film forming step is a distance within the range of 1 to 1.5 times the maximum width of the substrate. It has the structure of.
  Moreover, in order to solve the said subject, a claim6The described invention is a sputtering apparatus for creating a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
  A sputtering chamber equipped with an exhaust system, a gas introduction system for introducing a predetermined gas into the sputtering chamber, a target provided so that the surface to be sputtered is exposed in the sputtering chamber, and a voltage applied to the target Sputtering power source for sputtering the target, ionizing means for ionizing sputtered particles released from the target by sputtering, a substrate holder for holding the substrate at a predetermined position in the sputtering chamber, and sputtering ionized by the ionizing means Electric field setting means for setting an electric field for accelerating particles perpendicular to the substrate, a distance changing mechanism for changing the distance between the target and the substrate, an exhaust system, a gas introduction system, an ionization means, an electric field setting means, and a distance It has a control unit that can control the change mechanism,
  The control unit controls the exhaust system and the gas introduction system so as to keep the pressure in the sputter chamber at a high first pressure when operating the ionization means and the electric field setting means, and the target and the substrate. The distance changing means is controlled so that the distance to the first distance is short, and when the ionization means and the electric field setting means are not operated, the pressure in the sputtering chamber is lower than the first pressure. The exhaust system is controlled so as to maintain the pressure, and the distance changing means is controlled so that the distance between the target and the substrate becomes a second distance longer than the first distance.
  Moreover, in order to solve the said subject, a claim7The invention described is the above claim.6In the configuration, the sputtering power source is a high-frequency power source, the sputter particles can be ionized by an electric field set by the high-frequency power source, and the sputtering power source is also used as the ionization means, A negative DC power supply for applying a negative DC voltage to the target is provided, and a switch circuit is provided to selectively or simultaneously apply the high-frequency power supply voltage and the negative DC power supply voltage to the target. is doing.
  In order to solve the above problem, according to an eighth aspect of the present invention, in the configuration of the sixth aspect, the sputtering power source is a high frequency power source, and further, a negative DC power source that applies a negative DC voltage to the target. And a switch circuit that allows a voltage of a high-frequency power source and a voltage of a negative DC power source to be selectively or simultaneously applied to the target,
When depositing a large amount of thin film on the bottom surface of the inner surface of the hole, the control unit operates the sputtering power source, which is a high frequency power source, to apply a high frequency voltage to the target, and to the side surface of the inner surface of the hole. When many thin films are deposited, the negative DC power supply is operated to control to apply a negative DC voltage to the target.
  In order to solve the above problem, the invention according to claim 9 is the structure according to any one of claims 6 to 8, wherein the ionization means includes an auxiliary electrode provided separately from the target, and the auxiliary electrode. A capacitor that ionizes the sputtered particles by insulating from a ground potential or a high-frequency power source that ionizes the sputtered particles by applying a high-frequency voltage to the auxiliary electrode, and the auxiliary electrode includes the target and the target It has a configuration of a cylindrical shape surrounding the flying space of the sputtered particles between the substrate and the substrate.
  Moreover, in order to solve the said subject, a claim10The described invention is a multi-chamber type sputtering apparatus in which at least one load lock chamber and a plurality of processing chambers are hermetically connected around a separation chamber provided in the center, One is a first sputter chamber and the other is a second sputter chamber. The first sputter chamber includes a first exhaust system for evacuating the first sputter chamber and a first sputter chamber. A first gas introduction system for introducing a predetermined gas into the first target, a first target provided so that a surface to be sputtered is exposed in the first sputtering chamber, and applying a voltage to the first target to sputter the target. The first sputtering power source and the sputtered particles released from the first target by sputtering are ionized. An ionizing means for forming a substrate, a first substrate holder for holding the substrate at a predetermined position in the first sputtering chamber, and an electric field for accelerating the sputtered particles ionized by the ionizing means perpendicularly to the substrate. An electric field setting means, and the first exhaust system and the first gas introduction system can maintain a high first pressure in the first sputtering chamber, and the first substrate holder is a substrate. The substrate is held so that the distance between the first target and the first target is a short first distance. The second sputtering chamber includes a second exhaust system for exhausting the inside of the second sputtering chamber, and a second exhaust system. A second target provided so that the surface to be sputtered is exposed in the sputtering chamber, and a second sputter for sputtering the second target by applying a voltage to the second target. A power source and a second substrate holder for holding the substrate at a predetermined position in the second sputtering chamber are provided, and the second exhaust system has a second pressure lower than the first pressure in the second sputtering chamber. The second substrate holder is configured to hold the substrate such that a distance between the substrate and the second target is a second distance longer than the first distance. Have.
  In order to solve the above problem, the invention according to claim 11 is the configuration of claim 10, wherein the first sputter chamber is provided with an auxiliary electrode provided separately from the target, and the auxiliary electrode is grounded. A capacitor for ionizing the sputtered particles by insulating from a potential or a high-frequency power source for ionizing the sputtered particles by applying a high-frequency voltage to the auxiliary electrode, the auxiliary electrode comprising the target, the substrate, It has the structure that it is the cylindrical shape surrounding the flight space of the said sputtered particle in between.
  In order to solve the above problem, the invention according to claim 12 is the configuration according to claim 10 or 11, wherein the first sputtering power source is a high-frequency power source and the second sputtering power source is a negative DC power source. It has the structure of.
  In order to solve the above problems, the invention described in claim 13 is the above-mentioned claim.Any of 6-12In the configuration, the first pressure is in a range of 10 mTorr to 100 mTorr, the second pressure is 1 mTorr or less, and the first distance is 1 / 2.5 to 1/1 of the maximum width of the substrate. The second distance is within the range, and the second distance is within the range of 1 to 1.5 times the maximum width of the substrate.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
First, a first embodiment belonging to the invention of the sputtering apparatus according to claims 2 and 3 will be described. FIG. 1 is a schematic plan view showing a configuration of a sputtering apparatus according to a first embodiment belonging to the inventions of claims 2 and 3.
The sputtering apparatus shown in FIG. 1 is a multi-chamber type apparatus, which includes a separation chamber 1 disposed in the center, and a plurality of processing chambers 2, 3, 4, 8 and two that are hermetically connected around the separation chamber 1. The chamber is composed of a load lock chamber 5. Each chamber 1, 2, 3, 4, 5, 8 is provided with a dedicated or combined exhaust system (not shown) so that it is exhausted to a predetermined pressure. A gate valve 6 is provided at a connection location between the chambers.
[0010]
In the separation chamber 1, a transport robot 11 is provided as a transport mechanism for transporting the substrate 9 between the chambers. As the transfer robot 11, an articulated robot is used. The transfer robot 11 takes out the substrates 9 one by one from one of the load lock chambers 5 and sends them to the respective processing chambers 2, 3, 4 and 8 for sequential processing. The load lock chamber 5 is returned.
An autoloader 7 is provided outside the load lock chamber 5. The autoloader 7 takes out the substrates 9 one by one from the external cassette 62 on the atmosphere side, and stores them in the in-lock cassette 51 in the load lock chamber 5.
One of the plurality of processing chambers 2, 3, 4, and 8 is a sputtering chamber 4 that forms a predetermined thin film by sputtering. Further, one of the other processing chambers 2, 3, 8 is a preheating chamber 2 for preheating the substrate 9 before sputtering, and another one is natural oxidation of the surface of the substrate 9 before sputtering. This is a pretreatment etching chamber 3 for performing pretreatment etching for removing the film or the protective film.
[0011]
Next, the configuration of the sputter chamber 4 constituting the main part of the apparatus of this embodiment will be described with reference to FIG. FIG. 2 is a schematic front view showing the configuration of the sputtering chamber 4 shown in FIG.
As shown in FIG. 2, the sputtering chamber 4 includes an exhaust system 41 that exhausts the inside, a target 42 that is provided in the sputtering chamber 4 so that the surface to be sputtered is exposed, and a predetermined power to the target 42. Two sputtering power sources 421 and 422 to be applied, a magnet mechanism 43 provided behind the target 42, a gas introduction system 44 for introducing a predetermined sputtering gas into the sputtering chamber 4, and the sputtering chamber 4 facing the target 42. And a substrate holder 45 for placing the substrate 9 at a predetermined position.
[0012]
The exhaust system 41 uses a vacuum pump 411 such as a cryopump to move the inside of the sputter chamber 4 through 10.^-8It is configured to be able to exhaust to about Torr. The exhaust system 41 includes an exhaust speed regulator 412 such as a variable orifice.
The target 42 is attached to the sputter chamber 4 via an insulating material 420. The target 42 is made of titanium in this embodiment.
The two sputter power sources 421 and 422 are a major feature of the apparatus of this embodiment. One of the two sputtering power sources is a power source (hereinafter referred to as a sputtering DC power source) 421 that applies a negative DC voltage to the target 42, and the other one is a power source that applies a high frequency voltage (hereinafter referred to as a sputtering high frequency power source). 422.
As the DC power source 421 for sputtering, one that applies a voltage of about −400 to −600 V to the target 42 is used. The power supplied to the target 42 by the DC power source 421 for sputtering is about 10 to 20 kW. Further, as the sputtering high-frequency power source 422, a power source that applies a voltage having a frequency of 13.56 MHz and an effective value of about 300 to 500 V to the target 42 is used. The power supplied to the target 42 by the sputtering high-frequency power source 422 is about 3 to 8 kW. A matching unit 424 is provided between the sputtering high-frequency power source 422 and the switch circuit 423.
When the DC power source 421 for sputtering is used, the target 42 is sputtered in the same manner as normal DC sputtering. Further, when the sputtering high-frequency power source 422 is used, sputtering is performed according to the principle of high-frequency sputtering.
[0013]
The high-frequency sputtering will be described in more detail. A capacitance such as a capacitor is provided between the target 42 and the sputtering high-frequency power source 422. When a high frequency voltage is applied to the target 42 by the sputtering high frequency power source 422, a high frequency discharge is generated in the space facing the target 42, and plasma is formed. At this time, when a high frequency voltage is applied to the target 42 via the capacitance, electrons and positive ions in the plasma act on the charge and discharge of the capacitance, and a negative self-bias is applied to the substrate 9 due to the difference in mobility between the electrons and positive ions.VoltageOccurs. Plasma space potential is a positive potential of about 0 to 40 volts, and negative self-biasVoltageAn electric field in which the potential gradually decreases toward the target 42 is set between the target 42 and the plasma. The positive ions in the plasma are accelerated by this electric field and collide with the target 42, and the target 42 is sputtered to maintain the sputter discharge.
Note that the sputtering DC power supply 421 and the sputtering high-frequency power supply 422 are connected in parallel to the target 42, and a switch circuit 423 is provided at a branch portion thereof. As can be seen from FIG. 2, the switch circuit 423 is configured to be able to select whether to connect either the sputtering DC power supply 421 or the sputtering high frequency 422, or to connect both of them simultaneously.
[0014]
The magnet mechanism 43 includes a columnar central magnet 431 disposed at the center, a ring-shaped peripheral magnet 432 surrounding the central magnet 431, and a yoke 433 connecting the central magnet 431 and the peripheral magnet 432. The front surface of the central magnet 431 and the front surface of the peripheral magnet 432 are magnetic poles different from each other, and an arch-shaped magnetic field line 434 as shown in FIG.
The electric field set in the sputtering chamber 4 by the sputtering DC power supply 421 through the target 42 is orthogonal to the magnetic field in the vicinity of the apex of the arch-shaped magnetic field line 434. For this reason, in the sputter discharge to be formed, electrons start to perform a magnetron motion, and a magnetron discharge is achieved. For this reason, the ionization efficiency of neutral gas molecules is increased, and sputtering can be performed with high efficiency.
[0015]
In the present embodiment, the gas introduction system 44 introduces argon gas as a sputtering gas. The gas introduction system 44 includes a pipe 441 that connects the cylinder 442 storing the argon gas and the sputter chamber 4, a valve 443 provided on the pipe 441, a flow controller 444, and the like.
The substrate holder 45 is configured to place and hold the substrate 9 on the upper surface. The substrate holder 45 is provided with an electrostatic chucking mechanism for fixing the substrate 9 at a predetermined position by electrostatic chucking as required. A heater 451 for heating the substrate 9 to a predetermined temperature is provided in the substrate holder 45.
[0016]
A major feature of the apparatus of this embodiment is that the substrate holder 45 is provided with a distance changing mechanism 46 for changing the distance between the target 42 and the substrate 9. More specifically, the substrate holder 45 is supported by the support column 452. The distance changing mechanism 46 includes a holding plate 463 that holds the lower end of the column 452, a driven body 464 that fixes the holding plate 463, a ball screw 461 that drives the driven body 464, and a motor 462 that rotates the ball screw 461. And is composed mainly of.
[0017]
The driven body 464 is a cylindrical member having an inner diameter that matches the outer diameter of the ball screw 461. The inner surface of the driven body 464 is threaded with high accuracy and meshes with the ball screw 461. Further, the driven body 464 is prevented from rotating by a rotation stopper (not shown).
When the ball screw 461 is rotated by the motor 462, the rotational force is transmitted to the driven body 464. Since the driven body 464 is prevented from rotating by a rotation stopper (not shown), it only moves up and down. As a result, the support column 452 moves up and down via the holding plate 463 fixed to the driven body 464, and the substrate holder 45 also moves up and down accordingly. Since the target 42 is fixed in the sputter chamber 4, the distance between the substrate 9 placed on the substrate holder 45 and the target 42 can be changed by the operation of the distance changing mechanism 46 as described above. Yes.
The support 452 penetrates the bottom plate of the sputtering chamber 4 in an airtight manner. A sealing means 453 such as a mechanical seal that seals the penetrating portion while allowing vertical movement of the support column 452 is provided.
[0018]
Another feature of the apparatus of this embodiment is that ionized sputtering can be performed in the sputtering chamber 4. That is, the apparatus according to the present embodiment includes an ionization unit that ionizes the sputtered particles emitted from the target 42. The ionizing means is also used as the above-described sputtering high-frequency power supply 422. The ionizing means includes a sputtering high-frequency power supply 422, an auxiliary electrode 47 for effectively performing ionized sputtering, an electric field setting means 48, and the like. It is configured.
[0019]
The auxiliary electrode 47 has a cylindrical shape provided so as to surround the flying space of the sputtered particles between the target 42 and the substrate holder 45. The auxiliary electrode 47 is grounded via a capacitor 471 provided outside the sputtering chamber 4. An auxiliary power supply 472 is provided in parallel with the capacitor 471. A switch 473 is provided at a portion where the line to the auxiliary power source 472 and the line to the capacitor 471 branch, and the auxiliary electrode 47 is grounded via the capacitor 471 or grounded via the auxiliary power source 472. You can choose whether to do it. The auxiliary power supply 472 is a high frequency power supply, for example, having a frequency of 13.56 MHz and an output of about 2 kW. The sputter chamber 4 is grounded, and an insulating material (not shown) is provided in a portion where the line connecting the auxiliary electrode 47 and the switch 473 penetrates the wall of the sputter chamber 4 in an airtight manner.
[0020]
When the sputtering high-frequency power source 422 is operated in a state where the sputtering gas is introduced into the sputtering chamber 4 by the gas introduction system 44, the target 42 is subjected to high-frequency sputtering as described above. At this time, the gas is turned into plasma by the high frequency electric field to form plasma. Neutral sputtered particles emitted from the target 42 are in the plasma.TheWhen passing, it collides with ions and electrons in the plasma and ionizes (hereinafter referred to as ionized sputtered particles).
The ionized sputtered particles are accelerated by the electric field set by the electric field setting means 48 and extracted from the plasma, fly at an angle closer to the substrate 9 and enter the substrate 9. Specifically, the electric field setting means 48 employs a high-frequency power supply 481 that applies a high-frequency voltage to the substrate holder 45 and applies a negative self-bias voltage to the substrate 9 by the interaction between the high frequency and the plasma. As the high frequency power supply 481, for example, 13.56 MHz output 1kW grades can be used. A matching unit 482 is provided between the high frequency power supply 481 and the substrate holder 45. Further, when both the substrate 9 and the substrate holder 45 are conductors, a predetermined capacitor is provided in the high-frequency transmission path, and a high-frequency voltage is applied to the substrate 9 via the capacitor.
[0021]
As in the case of the sputtering high-frequency power source 422 described above, when a high-frequency voltage is applied to the substrate 9 via a capacitance, a self-bias voltage is generated on the substrate 9 and gradually toward the substrate 9 between the substrate 9 and the plasma. An electric field that lowers the potential is set. The direction of the electric field is perpendicular to the substrate 9, and the positively ionized sputtered particles are accelerated by the electric field and are incident on the substrate 9 perpendicularly.
In the ionization sputtering, ions in the plasma change the direction of movement so as to follow a periodic change in the direction of the electric field. At this time, the auxiliary electrode 47 is insulated from the ground potential by the capacitor 471 or is connected to the auxiliary power source 472.Near 47An electric field is also set. As a result, the ions move over a wide range, and there is a high probability that the ions collide with the neutral sputtered particles and ionize. That is, the auxiliary electrode 47 has an effect of increasing the ionization efficiency of the sputtered particles.
[0022]
In addition, the apparatus of the present embodiment has a control unit (not shown) that controls the operation in the sputtering chamber 4. This control unit sends control signals to the exhaust system 41, the sputtering power sources 421 and 422, the switch circuit 423, the gas introduction system 44, the heater 451, the distance changing mechanism 46, the ionization means 47, etc., and each unit performs the operations described later. It is configured as follows.
[0023]
Next, the operation of the apparatus in the sputtering chamber 4 will be described with reference to FIG.
First, the substrate 9 is carried into the sputtering chamber 4 from the separation chamber 1 through the gate valve 6 by the transfer robot 11. The inside of the sputtering chamber 4 is evacuated in advance to a predetermined pressure by an exhaust system 41, and the substrate 9 is placed on the substrate holder 45. The heater 451 in the substrate holder 45 is operated in advance, and the substrate 9 placed on the substrate holder 45 is rapidly heated to a predetermined temperature by the heat of the heater 451, and the temperature is maintained.
After the gate valve 6 is closed, the gas introduction system 44 operates to perform sputtering. A major feature of the apparatus and method of the present embodiment is that a bottom surface film forming step in which the film formation rate on the bottom surface of the hole is increased when film formation is performed on the substrate 9 having fine holes formed on the surface; This is a point that is separately performed from the side surface film forming step in which the film forming rate on the side surface of the hole is increased. Although the order is not particularly limited, in the following example, it is assumed that the bottom surface film forming step is first performed and then the side surface film forming step is performed.
[0024]
First, when performing the bottom film formation process, the exhaust speed regulator412And the flow rate regulator 444 is controlled to keep the inside of the sputtering chamber 4 at a high first pressure. Further, the distance changing mechanism 46 moves the substrate holder 45 in advance so that the distance between the target 42 and the substrate 9 (hereinafter referred to as TS distance) is a first distance that is short. In this state, the sputtering high frequency power supply 422 and the electric field setting means 48 are operated to perform ionization sputtering. That is, as described above, the sputtering high-frequency power source 422 performs high-frequency sputtering with the voltage applied to the target 42 and ionizes the sputtered particles in the plasma. Then, the ionized sputtered particles are drawn out by the electric field set by the electric field setting means 48 and are made incident vertically by the substrate 9. When the sputtered particles are vertically incident on the substrate 9, the sputtered particles easily reach the bottom surface of the hole, so that film deposition on the bottom surface of the hole is promoted. That is, the film formation rate on the bottom surface of the hole increases.Sputtering performed at such a low pressure and a long TS distance is called “low pressure remote sputtering”.
[0025]
Next, a side film forming process is performed. Specifically, the distance changing mechanism 46 is operated to move the substrate holder 45 in advance so that the TS distance becomes the second distance that is long. Also, exhaust speed regulator412And the flow rate regulator 444 is controlled to keep the inside of the sputter chamber 4 at a low second pressure. In this state, the sputtering DC power supply 421 is operated to perform DC sputtering. At this time, since the TS distance is long and the pressure is low, film deposition on the side surface of the hole is promoted, and sputtering with a high side surface deposition rate can be performed. Then, after performing this sputtering for a predetermined time, the operations of the sputtering high-frequency power source 422, the electric field setting means 48, the gas introduction system 44, etc. are stopped, and the substrate 9 is taken out from the sputtering chamber 4.
[0026]
The improvement of the side surface film forming speed in the operation in the sputtering chamber 4 will be described in more detail with reference to FIG. FIG. 3 is a diagram schematically illustrating the improvement of the side film formation rate.
As shown in FIG. 3, when the TS distance is increased from L1 to L2, the area of the sputtering surface of the target 42 that can be seen from one point P on the side surface of the hole 90 is L2 compared to L1. Increases (S1 <S2). Since the area (S1, S2) of the surface to be sputtered of the target 42 is the area of the sputtered particle emission portion that can reach one point P on the side surface of the hole, the area in the case of L2 is more pointed than L1. The amount of sputtered particles that reaches P increases. For this reason, the side surface film formation rate can be increased. Further, when the pressure is lowered, the sputtered particles flying toward the side surface of the hole 90 are less likely to be scattered by the gas molecules. For this reason, the sputtered particles reach the side surface of the hole 90 more reliably and contribute to the improvement of the side surface deposition rate.
[0027]
In the operation in the sputtering chamber 4, the high first pressure is preferably in the range of 10 mTorr to 100 mTorr. If it is higher than this range, ionized sputtered particles are scattered by the presence of a large number of gas molecules, and there is a problem that the substrate 9 cannot be sufficiently reached. Moreover, when it becomes lower than this range, there is a problem that the plasma density is lowered and the ionization efficiency is not sufficient. Further, the low second pressure is preferably set to 1 mTorr or less within a range where discharge is sustained. If the pressure is higher than this, there is a problem that the effect of the low-pressure remote sputtering described above cannot be obtained sufficiently.
Furthermore, specifically, the short first distance is preferably a distance within a range of 1 / 2.5 to 1/1 of the maximum width of the substrate 9. The “maximum width” of the substrate 9 means the width of the substrate 9 viewed in the direction in which the width is widest, and is the diameter if the substrate 9 is circular. If the first distance is shorter than the above range, the in-plane distribution of film characteristics such as film thickness may be deteriorated. On the other hand, if the length is longer than this range, the number of sputtered particles that cannot reach the substrate 9 increases unnecessarily, resulting in poor efficiency.
The long second distance is preferably a distance within a range of 1 to 1.5 times the maximum width of the substrate. If it is longer than this range, the efficiency of film formation becomes too bad, which is not suitable. Moreover, when it becomes shorter than this range, the effect of the low-pressure remote sputtering cannot be obtained.
[0028]
Next, returning to FIG. 1, another configuration of the sputtering apparatus of this embodiment will be described.
The pretreatment etching chamber 3 shown in FIG. 1 is configured to remove the natural oxide film and the protective film on the surface of the substrate 9 by etching the substrate 9 prior to film formation. The pretreatment etching chamber 3 forms plasma therein, and ions in the plasma collide with the surface of the substrate 9 to remove the natural oxide film and the protective film by etching.
Further, the preheat chamber 2 is configured to heat the substrate 9 prior to film formation and release the occluded gas of the substrate 9. When the occlusion gas is not released, the occlusion gas is abruptly released due to heat during film formation, and the film surface becomes rough due to foaming. A heat stage (not shown) that is heated and maintained at a predetermined temperature is provided in the preheat chamber 2. The substrate 9 is placed on the heat stage and preheated by being heated to a predetermined temperature.
[0029]
Next, the overall movement of the sputtering apparatus of this embodiment will be described.
The substrate 9 accommodated in the external cassette 62 is carried into the in-lock cassette 51 in the load lock chamber 5 by the autoloader 7. The substrate 9 loaded into the in-lock cassette 51 is first loaded into the preheat chamber 2 by the transfer robot 11 provided in the separation chamber 1. The substrate 9 carried into the preheat chamber 2 is placed on a heat stage (not shown) and heated to a predetermined temperature. As a result, the substrate 9 is preheated, and the occluded gas in the substrate 9 is released. Next, the substrate 9 is transferred to the pretreatment etching chamber 3, and the natural oxide film or protective film on the surface of the substrate 9 is etched. Thereafter, the substrate 9 is carried into the base film forming chamber 8, and a thin titanium film is formed as a base film.
Then, the substrate 9 is carried into the sputtering chamber 4. Then, as described above, the bottom surface film forming step and the side surface film forming step are performed in the sputter chamber 4. As a result, even when the substrate 9 has holes with a high aspect ratio, a thin film having a sufficient thickness is formed on the bottom and side surfaces of the holes.
[0030]
Thereafter, the substrate 9 is unloaded from the sputter chamber 4, and after processing such as formation of an antireflection film and cooling as necessary, the substrate 9 is accommodated in the in-lock cassette 51 in the load lock chamber 5 by the transfer robot 11. afterwards, Cassette in lockWhen a predetermined number of processed substrates 9 are accommodated in 51, the autoloader 7 operates to carry out the processed substrates 9 to the external cassette 62.
[0031]
An example of film formation will be described. The apparatus of the present embodiment is preferably used for creating a barrier film. Specifically, sputtering is performed using a target 42 made of titanium. At first, an argon gas is introduced to form a titanium thin film, and then a nitrogen gas is introduced to form a titanium nitride thin film while auxiliary use of the reaction between nitrogen and titanium. As a result, a barrier film structure in which a titanium nitride thin film is laminated on a titanium thin film is obtained.
In the apparatus of the present embodiment described above, a certain merit may be obtained even if the sputtering DC power supply 421 and the sputtering high frequency power supply 422 are operated simultaneously. When these are operated simultaneously, the negative DC voltage of the sputtering DC power supply 421 is superimposed on the high frequency voltage of the sputtering RF power supply 422 and applied to the target 42.
For example, when the above-described superposition is performed in the side surface film forming step, it is possible to perform film formation while ionizing a part of the sputtered particles while performing low-pressure remote sputtering and using ionized sputtering as an auxiliary. If the pressure is too low, the ionization efficiency is deteriorated, and if the pressure is high, the effect of low-pressure remote sputtering is reduced. Therefore, it is difficult to select the pressure at this time, but it may be about 1 to 1.5 mTorr, for example. Further, when the above superposition is performed in the bottom surface film forming step, ions are accelerated by the voltage of the DC power source 421 for sputtering in addition to the self-bias voltage described above, so that the overall sputtering efficiency is improved.
[0032]
In the apparatus of this embodiment, the sputtering high-frequency power source 422 is also used as the ionization means, but ionization may be performed using a power source different from the sputtering power source. Specifically, ionization may be performed by operating an auxiliary power source 472 provided on the auxiliary electrode 47 and mainly using high-frequency energy from the auxiliary power source 472.
[0033]
Next, a second embodiment belonging to the invention of claim 4 will be described.
FIG. 4 is a schematic plan view illustrating the configuration of the sputtering apparatus according to the second embodiment, and FIG. 5 is a schematic cross-sectional view taken along line XX of the sputtering apparatus shown in FIG.
In the apparatus of the first embodiment described above, the bottom surface film forming step and the side surface film forming step are continuously performed in one sputter chamber 4. However, two sputter chambers can be provided so that the bottom film forming process is performed in one sputter chamber and the side film forming process is performed in the other sputter chamber. The apparatus shown in FIGS. 4 and 5 has this configuration.
Specifically, as shown in FIG. 4, two of the plurality of processing chambers are sputter chambers 81 and 82. One of the two sputter chambers is a first sputter chamber 81 that performs a bottom surface film forming step, and the other is a second sputter chamber 82 that performs a side surface film forming step.
[0034]
As shown in FIG. 5, the two sputter chambers 81 and 82 have substantially the same configuration as the sputter chamber of the first embodiment shown in FIG. That is, the first sputtering chamber 81 includes a first exhaust system 811 for exhausting the inside, a first target 812 with the surface to be sputtered exposed inside, a first sputtering power source 813 for sputtering the first target 812, , A first gas introduction system 814 for introducing gas into the interior, and a first substrate holder 815 for holding the substrate 9 at a predetermined position inside. The second sputtering chamber 82 includes a second exhaust system 821 for exhausting the inside, a second target 822 with the surface to be sputtered exposed inside, a second sputtering power source 823 for sputtering the second target 822, , A second gas introduction system 824 for introducing gas into the inside, and a second substrate holder 825 for holding the substrate 9 at a predetermined position inside.
[0035]
The first sputtering power supply 813 is a high-frequency power supply similar to the sputtering high-frequency power supply 422 in the first embodiment. A matching unit (not shown) is provided between the first sputtering power supply 813 and the first target 812. The first substrate holder 815 is configured to hold the substrate 9 so that the first distance is a short TS distance.
Further, an auxiliary electrode 817 similar to the auxiliary electrode 47 of the first embodiment is provided in the first sputter chamber 81, and the substrate holder 815 is similar to the electric field setting means 48 of the first embodiment. Electric field setting means 818 is provided.
On the other hand, the second sputtering power source 823 of the second sputtering chamber 82 is a negative DC power source similar to the sputtering DC power source 421 in the first embodiment. The second substrate holder 825 has a TS distance oflongThe substrate 9 is configured to be held at the second distance.
[0036]
In the apparatus according to the second embodiment having the above-described configuration, the substrate 9 is formed in the first sputter chamber 81 by increasing the film forming speed on the bottom surface of the hole by ionization sputtering, and the second sputter chamber 82 is operated at a low pressure remote. Film formation is performed by increasing the film formation speed on the side surface of the hole by sputtering. Also in this case, as in the case of the first embodiment, it is possible to form a film with a sufficient thickness on the inner surface of a very high aspect ratio hole having an aspect ratio of 7 or more.
In addition, since the bottom surface film forming step and the side surface film forming step are continuously performed in a vacuum, the substrate 9 is not contaminated between the two steps, and a high-quality thin film can be formed. In addition, since the bottom surface film forming step and the side surface film forming step are performed in different sputtering chambers 81 and 82, the tact time can be shortened. Therefore, in the first embodiment described above, when the processing in the sputter chamber 4 among the processing chambers takes the longest time, the productivity can be improved according to the second embodiment. However, since there are two sputter chambers, the cost of the apparatus increases. Conversely, the first embodiment described above is advantageous in terms of the cost of the apparatus.
[0037]
【Example】
Next, examples of the invention of the above embodiment will be described.
First, conditions common to both the bottom surface film forming step and the side surface film forming step are as follows.
・ Substrate: 200 mm diameter silicon wafer
・ Hole: Opening diameter 0.4μm, depth 2μm, aspect ratio 5
・ Target: 300mm diameter titanium
[0038]
Moreover, the conditions of a bottom surface film-forming process can be performed on condition of the following.
・ Film pressure: 60 mTorr
・ Discharging gas: Argon or nitrogen
・ Gas flow rate: 60cc / min
・ Sputtering power supply: frequency 13.56MHz output 3kW
・ Applied voltage to target; 300V
・ TS distance: 90mm
-Substrate temperature: 350 ° C
・ Substrate self-bias voltage: 100V
Under the above conditions, a thin film can be formed at a deposition rate of about 350 angstroms per minute with respect to the bottom surface of the hole. In this case, the bottom coverage ratio (ratio of the film formation rate on the bottom surface of the hole with respect to the surface outside the hole) is about 70%.
[0039]
Further, the side surface film forming step can be performed under the following conditions.
・ Film pressure: 0.3 mTorr
・ Discharging gas: Argon or nitrogen
・ Gas flow rate: 10cc / min
・ Sputtering power supply: -600V
・ Power input to the target: 12kW
・ TS distance: 230mm
-Substrate temperature: 350 ° C
Under the above conditions, a thin film can be formed at a film formation rate of about 700 angstroms per minute with respect to the side surface of the hole. At this time, the side coverage ratio (ratio of the film formation rate on the side surface of the hole to the surface outside the hole) is about 25%.
[0040]
In each of the above-described embodiments and examples, a thin film having a necessary thickness may be formed in a plurality of times instead of being formed once in the bottom surface forming step and once in the side surface forming step. That is, for example, the side surface film forming step may be performed after the bottom surface film forming step, and this cycle may be repeated a plurality of times. In this way, a structure is obtained in which the thin films created in the bottom film formation process and the thin films created in the side film formation process are alternately stacked. When there is a slight difference in characteristics between the thin film formed in the bottom surface film formation step and the thin film formed in the side surface film formation step, there is an advantage that this difference can be relaxed and a uniform thin film can be formed as a whole.
[0041]
【The invention's effect】
  As explained above, the method and claim of claim 1 of the present application.6According to this apparatus, since the bottom surface film forming step by ionization sputtering and the side surface film forming step by low-pressure remote sputtering are continuously performed in a vacuum, a sufficient thickness can be applied to the inner surface of a hole having an aspect ratio of 7 or more. Thus, film formation can be performed. Accordingly, it is possible to provide a breakthrough for the production of next-generation devices having a line width of 0.18 μm or less.
  Claims7According to the apparatus of claim6In addition to the above effect, the cost of the apparatus can be reduced because only one sputter chamber is required.
  According to the invention of claim 10,6In addition to the above effect, the bottom film forming step and the side film forming process are performed in different sputtering chambers, so the tact time can be shortened and the productivity can be increased.
  And claims13According to the invention, the pressure and TS distance conditions in the bottom film formation step and the side film formation step are optimized, and the above claims6The effect of can be obtained more reliably.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a configuration of a sputtering apparatus according to a first embodiment belonging to the inventions of claims 2 and 3;
2 is a schematic front view showing a configuration of a sputtering chamber 4 shown in FIG. 1. FIG.
FIG. 3 is a diagram schematically illustrating an improvement in side film formation rate.
FIG. 4 is a schematic plan view illustrating the configuration of a sputtering apparatus according to a second embodiment.
5 is a schematic sectional view taken along line XX of the sputtering apparatus shown in FIG.
FIG. 6 is a diagram illustrating technical difficulty of film formation for a high aspect ratio hole.
[Explanation of symbols]
1 Separation chamber
11 Transport robot
2 Preheat chamber
3 Pretreatment etching chamber
4 Sputter chamber
41 Exhaust system
42 Target
421 DC power supply for sputtering
422 High frequency power supply for sputtering
423 switch circuit
43 Magnet mechanism
44Gas introduction system
45 Substrate holder
451 heater
46 Distance change mechanism
47 Auxiliary electrode
471 capacitor
472 Auxiliary power supply
5 Load lock chamber
6 Gate valve
7 Autoloader
81 First sputter chamber
82 Second Sputter Chamber
9 Board

Claims (13)

A sputtering method for creating a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
With ionizing the sputtering particles emitted from the target, the hole by the operating the field setting means for setting a field having a depth to a component of the holes are accelerated by an electric field due to the electric field setting means sputtered particles ionized Film formation on the side surface of the hole by performing sputtering with a longer distance between the target and the substrate and lowering the pressure compared to the bottom film formation process A side film forming process for increasing the speed, and the bottom film forming process and the side film forming process are continuously performed in a vacuum ,
The side film forming step is a step performed without setting an electric field by the electric field setting means . The pressure in the bottom surface deposition step is in the range of 10 mTorr to 100 mTorr, the pressure in the side surface deposition step is 1 mTorr or less, and the distance between the target and the substrate in the bottom surface deposition step is the maximum width of the substrate The distance between the target and the substrate in the side surface film forming step is a distance within the range of 1 to 1.5 times the maximum width of the substrate. The sputtering method according to claim 1. 3. The sputtering according to claim 1, wherein sputtering is performed by applying a high-frequency voltage to the target in the bottom surface deposition step, and sputtering is performed by applying a negative DC voltage to the target in the side surface deposition step. The sputtering method as described. The auxiliary electrode provided separately from the target is insulated from a ground potential or is a method of ionizing the sputtered particles by applying a high-frequency voltage to the auxiliary electrode. The auxiliary electrode includes the target and the substrate. The sputtering method according to any one of claims 1 to 3, wherein the sputtering method has a cylindrical shape surrounding a flying space of the sputtered particles. A sputtering method for creating a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
  The sputtered particles emitted from the target are ionized, and an electric field having a component in the depth direction of the hole is set, and the ionized sputtered particles are accelerated by this electric field to increase the deposition rate on the bottom surface of the hole. A bottom film forming step, and a side film forming process for increasing the film forming rate on the side surface of the hole by increasing the distance between the target and the substrate and lowering the pressure as compared with the bottom film forming process. , The bottom film forming step and the side film forming step are continuously performed in a vacuum,
The pressure in the bottom surface deposition step is in the range of 10 mTorr to 100 mTorr, the pressure in the side surface deposition step is 1 mTorr or less, and the distance between the target and the substrate in the bottom surface deposition step is the maximum width of the substrate The distance between the target and the substrate in the side surface film forming step is a distance within the range of 1 to 1.5 times the maximum width of the substrate. A sputtering method characterized by the above. A sputtering apparatus for creating a predetermined thin film by sputtering on the inner surface of a hole formed on the surface of a substrate,
A sputtering chamber equipped with an exhaust system, a gas introduction system for introducing a predetermined gas into the sputtering chamber, a target provided so that the surface to be sputtered is exposed in the sputtering chamber, and a voltage applied to the target Sputtering power source for sputtering the target, ionizing means for ionizing sputtered particles released from the target by sputtering, a substrate holder for holding the substrate at a predetermined position in the sputtering chamber, and sputtering ionized by the ionizing means Electric field setting means for setting an electric field for accelerating particles perpendicular to the substrate, a distance changing mechanism for changing the distance between the target and the substrate, an exhaust system, a gas introduction system, an ionization means, an electric field setting means, and a distance It has a control unit that can control the change mechanism,
The control unit controls the exhaust system and the gas introduction system so as to keep the pressure in the sputter chamber at a high first pressure when operating the ionization means and the electric field setting means, and the target and the substrate. The distance changing mechanism is controlled so that the distance to the first distance is short, and when the ionization means and the electric field setting means are not operated, the pressure in the sputtering chamber is lower than the first pressure. A sputtering apparatus characterized by controlling the exhaust system so as to maintain a pressure and controlling the distance changing mechanism so that the distance between the target and the substrate becomes a second distance longer than the first distance. The sputter power source is a high frequency power source, and the sputtered particles can be ionized by an electric field set by the high frequency power source. The sputter power source is also used as the ionization means. A negative DC power supply for applying a DC voltage is provided, and a switch circuit is provided so that the voltage of the high frequency power supply and the voltage of the negative DC power supply are selectively or simultaneously applied to the target. The sputtering apparatus according to claim 6 . The sputtering power source is a high frequency power source, and further, a negative direct current power source for applying a negative direct current voltage to the target is provided, and the high frequency power source voltage and the negative direct current power source voltage are selectively or simultaneously selected. Having a switch circuit to be applied to the target;
  When depositing a large amount of thin film on the bottom surface of the inner surface of the hole, the control unit operates the sputtering power source, which is a high frequency power source, to apply a high frequency voltage to the target, and to the side surface of the inner surface of the hole. 7. The sputtering apparatus according to claim 6, wherein when depositing a large number of thin films, a negative DC power source is operated to control application of a negative DC voltage to the target. The ionization means includes an auxiliary electrode provided separately from the target, a capacitor that ionizes the sputtered particles by insulating the auxiliary electrode from a ground potential, or applying a high-frequency voltage to the auxiliary electrode. 9. A high-frequency power source for ionizing particles, and the auxiliary electrode has a cylindrical shape surrounding a flying space of the sputtered particles between the target and the substrate. A sputtering apparatus according to 1. A multi-chamber type sputtering apparatus in which at least one load lock chamber and a plurality of processing chambers are hermetically connected around a separation chamber provided in the center,
One of the plurality of processing chambers is a first sputtering chamber and the other is a second sputtering chamber,
The first sputtering chamber includes a first exhaust system for exhausting the first sputtering chamber, a first gas introduction system for introducing a predetermined gas into the first sputtering chamber, and a surface to be sputtered in the first sputtering chamber. A first target provided so as to be exposed, a first sputtering power source for sputtering the target by applying a voltage to the first target, and ionization for ionizing sputtered particles emitted from the first target by sputtering Means, a first substrate holder for holding the substrate at a predetermined position in the first sputter chamber, and an electric field setting means for setting an electric field for accelerating the sputtered particles ionized by the ionizing means perpendicularly to the substrate. The first exhaust system and the first gas introduction system maintain a high first pressure in the first sputter chamber. Rukoto are possible, also, the first substrate holder is to hold a substrate such as a substrate and the distance is short first distance between the first target,
The second sputter chamber has a second exhaust system for exhausting the inside of the second sputter chamber, a second target provided so that a surface to be sputtered is exposed in the second sputter chamber, and a voltage applied to the second target. And a second substrate holder for holding the substrate at a predetermined position in the second sputtering chamber, and the second exhaust system is provided with a second sputtering system. The inside of the sputtering chamber can be maintained at a second pressure lower than the first pressure, and the second substrate holder has a second distance in which the distance between the substrate and the second target is longer than the first distance. A sputtering apparatus which holds a substrate so that The first sputter chamber is provided separately from the target. And a capacitor for ionizing the sputtered particles by insulating the auxiliary electrode from a ground potential or a high frequency power source for ionizing the sputtered particles by applying a high frequency voltage to the auxiliary electrode. The sputtering apparatus according to claim 10, wherein the auxiliary electrode has a cylindrical shape surrounding a flying space of the sputtered particles between the target and the substrate. The sputtering apparatus according to claim 10 or 11, wherein the first sputtering power source is a high-frequency power source, and the second sputtering power source is a negative DC power source. The first pressure is in the range of 10 mTorr to 100 mTorr, the second pressure is 1 mTorr or less, and the first distance is in the range of 1 / 2.5 to 1/1 of the maximum width of the substrate. 13. The sputtering apparatus according to claim 6, wherein the second distance is a distance within a range of 1 to 1.5 times the maximum width of the substrate.

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