WO2016203585A1 - Film forming method and film forming device - Google Patents

Abstract

This method is a film forming method comprising forming a thin film by performing plasma treatment in which a plurality of substrates S to which a voltage is applied are sequentially introduced to a predetermined position in a film forming region 20 reached by sputtering particles released from targets 29a, 29b by a sputtering plasma from a sputtering electrical discharge, whereby the sputtering particles reach the surface of the substrates S and accumulate thereon, and ions in the sputtering plasma impinge on the substrates S or a deposit of the sputtering particles, deposition of sputtering particles and plasma treatment by a sputtering plasma being performed in the film forming region 20 formed in a vacuum container 11 having an exhaust system, and an intermediate thin film being formed, after which the substrates S are moved into a reaction region 60 disposed so as to be spatially separated from the film forming region 20, plasma re-treatment is performed in which ions in a plasma separate from the sputtering plasma are caused to impinge on the intermediate thin film, and a thin film is formed.

Description

Film forming method and film forming apparatus

The present invention relates to a film forming method and a film forming apparatus by bias sputtering.

As one of sputtering deposition methods, which is a kind of deposition method using plasma reaction, a potential is applied to the substrate electrode on which the substrate is placed in addition to the cathode electrode on which the target is placed, and the substrate electrode is placed on the substrate electrode. A method of forming a thin film while applying a bias voltage to a placed substrate (bias sputtering method) is known (Patent Documents 1 and 2).

The principle of this bias sputtering method is generally as follows. When an atmosphere gas such as a rare gas is introduced into the system, electric power is supplied to the cathode electrode on which the target is placed to apply a potential, and the introduced gas is discharged in the space between the cathode electrode and the substrate electrode. Part of all ions generated in the plasma generated by the discharge is attracted to and collides with the target, ejects the target material, and consists of a deposit of the target material on the surface of the substrate disposed opposite to the target. A thin film is formed (sputter deposition). At the same time, by supplying power to the substrate electrode on which the substrate is placed, a potential is applied to the plasma on the substrate electrode, and the remainder of all ions existing in the plasma is attracted to the substrate. Energy is applied to the target material that has collided and deposited on the substrate (plasma treatment), thereby imparting a predetermined function to the thin film.

As a function imparted by the plasma treatment, for example, the film quality becomes dense and the hardness is improved (Patent Document 1), and step coverage (covered state with a fine step portion) is improved. And the bottom are formed with a substantially uniform film thickness (Patent Document 2). The former is due to film formation assistance by ions in the plasma, and the latter is due to the etching effect by the ions.

JP 2002-256415 A Japanese Patent Application Laid-Open No. 11-509049

All of the conventional film formation methods using the bias sputtering method, including the methods disclosed in Patent Documents 1 and 2, sputter film formation of ions generated in a single plasma generated between the cathode electrode and the substrate electrode. And both plasma processing. In other words, sputtering film formation and plasma processing are performed in the same region. For this reason, there was a problem that controllability was low.

For example, when it is desired to improve the effect of the plasma treatment, in the conventional film formation method, 1) a method of increasing the power supplied to the substrate electrode, thereby increasing the bias voltage applied to the substrate, or 2) the cathode Either a method of increasing the power supplied to the electrodes and thereby increasing the power for sputtering the target must be employed.

However, in the case of the method 1), the energy increases with the density of ions irradiated onto the substrate, so that the substrate may be damaged (damaged) depending on the material of the substrate used. In the case of the method 2), the density of ions colliding with the target is increased, thereby increasing the amount of target material sputtered from the target (increasing the deposition rate), so that the desired deposition rate can be maintained. Disappear.

In one aspect of the present invention, there is provided a film forming method and a film forming apparatus using a bias sputtering method capable of adjusting the effect of plasma treatment while maintaining a desired film forming rate while suppressing damage to a substrate. .

According to the present invention, a plurality of substrates to which a voltage is applied are sequentially introduced into a predetermined position in a film formation region where sputtered particles emitted from a target reach by sputtering plasma by sputtering discharge. In the film forming method for forming a thin film by causing the sputtered particles to reach the surface and depositing them, and performing a plasma treatment in which ions in the sputtering plasma collide with a substrate or a deposit of sputtered particles,
An intermediate thin film is formed by depositing sputtered particles and performing plasma treatment with sputtering plasma in a film formation region formed in a single vacuum chamber having an exhaust system, and then spatially separating the film formation region. A thin film is formed by moving the substrate within the reaction region (that is, from the deposition region to the reaction region) and performing plasma reprocessing that causes ions in the plasma other than the sputtering plasma to collide with the intermediate thin film. Is provided.

In the above invention, a film formation region for releasing sputtered particles from a target by sputtering plasma by sputtering discharge and a reaction region for generating plasma different from sputtering plasma are respectively spaced in a single vacuum chamber having an exhaust system. This can be realized by using a film forming apparatus which is arranged separately and configured so that processing in each region can be controlled independently.

Specifically, in the film formation method for forming a thin film on each surface of a plurality of substrates using the film formation apparatus as an example,
Generating a sputtering plasma by sputtering discharge in the film formation region;
Generating a plasma in the reaction region different from the sputtering plasma;
Applying a voltage to each of the plurality of substrates;
A plurality of substrates to which a voltage is applied at least from a predetermined position in a film formation region where sputtered particles emitted from the target by sputtering plasma reach a predetermined region in a reaction region exposed to a plasma different from the sputtering plasma. And moving to a position,
The intermediate thin film is formed by performing plasma treatment that causes the sputtering particles emitted from the target to reach and deposit on the substrate introduced into the film formation region, and at the same time, the ions in the sputtering plasma collide with the substrate or deposits of the sputtered particles. Provided with a film forming method characterized by forming a thin film by performing plasma reprocessing on the intermediate thin film of the substrate that has moved to the reaction region after formation and causing ions in the plasma different from the sputtering plasma to collide Is done.

In the above invention, when forming a thin film, the formation of the intermediate thin film and the plasma retreatment may be performed at least once. Preferably, a thin film having a target thickness can be formed by repeating the formation of the intermediate thin film and the film conversion to the ultra thin film a plurality of times for the ultra thin film after the first plasma reprocessing.

In the above-described invention, in the film forming region, a target made of metal is sputtered in an atmosphere of an operating gas, a sputtered particle is deposited and plasma treatment is performed by sputtering plasma, and a continuous intermediate made of metal or an incomplete reaction product of metal. A thin film or a discontinuous intermediate thin film is formed, and in the reaction region, the active species of the electrically neutral reactive gas in the plasma generated under the atmosphere containing the reactive gas is moved in the middle of the moved substrate. The film can be converted into a continuous ultrathin film made of a complete reaction product of a metal by contacting it with a thin film.

In the above invention, an inert gas is introduced into the film formation region as an operating gas, and an ionized inert gas is generated in the sputtering plasma, and the inert gas, the reactive gas, and the inert gas are generated in the reaction region. One of the mixed gas of the reactive gas and the reactive gas may be introduced to produce an ionized gas in a plasma different from the sputtering plasma.

In the above invention, by holding a plurality of substrates on the outer peripheral surface and rotating a cylindrical substrate holder while applying a voltage, the plurality of substrates to which a voltage is applied react with a predetermined position in the film formation region. The thin film can also be formed by moving between a predetermined position of the region, thereby repeating the formation of the intermediate thin film and the conversion to the ultra thin film.

In the above invention, as a power supply source for applying a voltage to a plurality of substrates, a power supply source that can be connected to one or both of a DC power supply and a high-frequency power supply can be used.

In the above invention, the voltage applied to each of the plurality of substrates (output voltage when based on power supplied from a DC power supply, self-bias voltage when based on power supplied from a high frequency power supply) is set to 5 to 1000 V be able to.

In the above invention, plasma can be generated in the reaction region by applying an AC voltage having a frequency of 10 kHz to 2.5 GHz from an AC power source.

As an example of realizing the formation of the intermediate thin film and the film conversion to the ultrathin film a plurality of times, for example, a film forming apparatus having the following configuration can be used.
According to the present invention, a vacuum chamber having an exhaust system;
A film formation region formed in the vacuum chamber;
A reaction region formed in the vacuum chamber and spatially separated from the film formation region;
A cathode electrode on which the target is mounted;
A sputtering power source for generating a sputter discharge in a film formation region facing the target surface to be sputtered;
Plasma generating means for generating in the reaction region a plasma different from the sputtering plasma generated by the sputter discharge generated in the film formation region;
A cylindrical substrate holder for holding a plurality of substrates on the outer peripheral surface;
Driving means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region where the sputtered particles emitted from the target by the sputtering plasma reach, and a predetermined position in the reaction region exposed to plasma different from the sputtering plasma In the film forming apparatus in which the substrate is repeatedly moved between
A substrate electrode for mounting the substrate held by the substrate holder from the back surface;
There is provided a film forming apparatus further provided with a bias power source for supplying power to the substrate electrode.

In the above invention, the film forming apparatus mounts the target on the cathode electrode, turns on the sputtering power, operates the plasma generating means, holds a plurality of substrates on the outer peripheral surface of the substrate holder, and supplies power to the substrate electrode. Then, by rotating the substrate holder while applying a voltage to the substrate, the sputtered particles emitted from the target reach and deposit on the substrate that has moved to the deposition region, and at the same time, ions in the sputtering plasma are deposited on the substrate. Alternatively, after plasma processing is performed to collide with the deposit of sputtered particles, an intermediate thin film is formed, and then plasma reprocessing is performed on the intermediate thin film on the substrate that has moved to the reaction region to cause ions in the plasma other than the sputtering plasma to collide. To convert to ultra-thin film, and then stack multiple ultra-thin films to form a thin film It can be configured.

“Movement” as used in the above invention includes linear movement in addition to curvilinear movement (for example, circumferential movement). Therefore, “move the substrate from the film formation region to the reaction region” includes not only a mode of revolving around a certain central axis but also a mode of reciprocating on a straight track connecting two points.

“Rotation” as used in the above invention includes not only rotation but also revolution. Therefore, in the case of simply “rotating around the central axis”, a mode of revolving is included in addition to a mode of rotating about a certain central axis.

In the above invention, the “intermediate thin film” is a film formed by passing through a film forming region. In addition, “ultra-thin film” is a term used to prevent confusion with this “thin film” because an ultra-thin film is deposited several times to form a final thin film. It means that it is thin enough.

According to the above invention, after the film formation by the conventional bias sputtering method is performed in the film formation region formed in the single vacuum chamber, the film formation region is arranged spatially separated. Plasma reprocessing is performed in which ions in the plasma different from the sputtering plasma generated in the reaction region collide with ions in the plasma. That is, plasma treatment is again performed on the thin film after bias sputtering. As a result, the effect of the plasma treatment can be independently controlled without increasing the voltage applied to the substrate or the sputtering power.
That is, according to the present invention, the effect of the plasma treatment can be adjusted while maintaining a desired film formation rate while suppressing damage to the substrate.

FIG. 1 is a partial cross-sectional view showing an example of a film forming apparatus for realizing the method of the present invention. FIG. 2 is a partial longitudinal sectional view taken along line II-II in FIG. FIG. 3 is a graph showing the relationship between the plasma processing power in the reaction region and the film hardness of the thin film in Experimental Example 1. FIG. 4 is a graph showing the relationship between the plasma processing power in the reaction region and the etching rate for the thin film in Experimental Example 2. FIG. 5 is a cross-sectional view showing an example after the embedded film formation on the pattern substrate.

DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus, 11 ... Vacuum container, 13 ... Substrate holder, S ... Substrate, 12, 14, 16 ... Partition wall, 15 ... Shaft, 18 ... Substrate electrode, 19 ... Electrode supply source, 19a ... Wiring member,
20, 40 ... deposition region, sputtering source (21a, 21b, 41a, 41b ... magnetron sputtering electrode, 23, 43 ... AC power supply, 24, 44 ... transformer, 29a, 29b, 49a, 49b ... target), sputtering gas Supply means (26, 46 ... gas cylinder for sputtering, 25, 45 ... mass flow controller),
60 ... Reaction region, 80 ... Plasma source (81 ... Case body, 82 ... Antenna housing chamber, 83 ... Dielectric plate, 85a, 85b ... Antenna, 87 ... Matching box, 89 ... AC power source), Reaction processing gas supply means (68 ... Reaction gas cylinder, 67 ... Mass flow controller).

Hereinafter, an embodiment of the method of the present invention will be described in detail with reference to the accompanying drawings.
First, a configuration example of a film forming apparatus that can realize the method of the present invention will be described.

A film forming apparatus 1 shown in FIGS. 1 and 2 is an example of a film forming apparatus of the present invention, and is a so-called carousel type apparatus that can form a film on a plurality of substrates S by a single process. A vacuum vessel 11 is provided, and a cylindrical rotating body is disposed in the vacuum vessel 11.
In this example, the vacuum vessel 11 is a side wall extending in the vertical direction (the paper surface direction in FIG. 1 and the vertical direction in FIG. 2; the same applies hereinafter), and in the plane direction (the direction perpendicular to the vertical direction. 2 (the same applies hereinafter), and has a chamber main body. In this example, the cross section of the chamber body in the planar direction is rectangular, but other shapes (for example, a circle) may be used. The vacuum vessel 11 is made of a metal such as stainless steel.

In the vacuum vessel 11, a hole for allowing the shaft 15 (see FIG. 2) to pass therethrough is formed, and is electrically grounded to a ground potential. An exhaust pipe 15 a is connected to the vacuum vessel 11. A vacuum pump 15 for exhausting the inside of the vacuum vessel 11 is connected to the pipe 15a, and the degree of vacuum inside the vacuum vessel 11 can be adjusted by the vacuum pump 15 and a controller (not shown). The vacuum pump 15 can be composed of, for example, a rotary pump or a turbo molecular pump (TMP).

In this example, the shaft 15 is formed of a substantially pipe-like member, and rotates with respect to the vacuum container 11 via an insulating member (not shown) disposed in a hole formed above the vacuum container 11. Supported as possible. The shaft 15 can be rotated with respect to the vacuum vessel 11 while being electrically insulated from the vacuum vessel 11 by being supported by the vacuum vessel 11 via an insulating member made of insulator, resin, or the like. .

In the present example, a first gear (not shown) is fixed to the upper end side of the shaft 15 located outside the vacuum vessel 11, and this first gear is a second gear (not shown) on the output side of the motor 17. (Shown). For this reason, when the motor 17 is driven, a rotational driving force is transmitted to the first gear via the second gear, and the shaft 15 rotates.
A cylindrical rotating body (rotating drum) is attached to the lower end portion of the shaft 15 located inside the vacuum vessel 11.

In this example, the rotating drum is disposed in the vacuum vessel 11 such that the axis Z extending in the cylinder direction is directed in the vertical direction (Y direction) of the vacuum vessel 11. The rotating drum has a cylindrical shape in this example, but is not limited to this shape, and may be a polygonal column shape having a polygonal cross section or a conical shape. The rotating drum rotates around the axis Z through the rotation of the shaft 15 driven by the motor 17.

A substrate holder 13 is mounted on the outer side (outer periphery) of the rotating drum. A plurality of substrate holders (for example, concave portions, not shown) are provided on the outer peripheral surface of the substrate holder 13, and a plurality of substrates S as film formation targets are formed by the substrate holders. It means the surface on the opposite side.) In this example, the axis (not shown) of the substrate holder 13 and the axis Z of the rotating drum coincide. For this reason, the substrate holder 13 rotates around the axis Z to synchronize with this rotation, and rotates around the axis Z of the drum integrally with the rotation drum.

Each of the plurality of substrate holders provided on the outer peripheral surface of the substrate holder 13 is equipped with a substrate electrode 18 for mounting the substrate S from the back surface. Each substrate electrode 18 is made of, for example, a plate-shaped member made of stainless steel, and is connected to a power supply source 19 outside the vacuum vessel 11 via a wiring member 19a.
In this example, the power supply source 19 is configured to be connectable to one or both of a direct current (DC) power source and a high frequency (RF) power source (the detailed structure is not shown). When a film is formed on the insulating substrate S, or when an insulator is used as a film forming material attached to the substrate S, only the RF power source or a combination of the RF power source and the DC power source can be used. When a conductive film forming material is formed on the conductive substrate S, only a DC power source or a combination of an RF power source and a DC power source can be used.

In this example, a filter (not shown) may be connected in series between the substrate electrode 18 and the DC power source. By doing so, it is possible to effectively flow high-frequency power from the RF power source toward the substrate electrode 18 without flowing it to the DC power source (cut off by the filter). Further, a matching unit (matching box) for impedance matching may be connected in series between the substrate electrode 18 and the RF power source.
In this example, the wiring member 19a passes from the power supply side outside the vacuum vessel 11 to the inside of the rotary drum disposed in the vacuum vessel 11 through the inside of the shaft 15 formed by a substantially pipe-shaped member. The shape is extended.

Each substrate electrode 18 is disposed at a predetermined distance (d) from the back surface of each substrate S to be disposed, and in parallel to face the back surface of each substrate S. The distance d between the substrate S and the substrate electrode 18 (more precisely, the distance between the back surface of the substrate S and the surface of the substrate electrode 18) is within a range in which the effect of self-bias by the substrate electrode 18 is reflected on the substrate S. Is set. The self-bias effect reflected on the substrate S can be adjusted by changing the distance d. Of course, the self-bias potential may be adjusted by changing the sputtering power.

Depending on the film forming conditions, in this example, the self-bias effect by the substrate electrode 18 affects the substrate S when the distance d is about 0.20 mm or less. As a result of film formation experiments by changing the film formation conditions such as the material of the substrate S, the power value supplied from the power supply source 19 to the substrate electrode 18 and the film formation atmosphere, the distance d is 0.10 to 0.00. A good film was obtained within a range of 14 mm. For this reason, it is preferable to set the distance d within the range. The adjustment of the self-bias effect is performed by changing the distance d or the power value. Of course, the distance d is adjusted within the above range.

The adjustment of the distance d can be performed, for example, by inserting a conductive or insulating spacer (not shown) on the back surface of the substrate electrode 18. In this example, the distance d is adjusted for each substrate electrode 18, but the distance d can also be set collectively by configuring each substrate electrode 18 as one body.

The size of each substrate electrode 18 is determined in consideration of the size of each substrate S. The substrate electrode 18 is preferably 80% or more, particularly 90% or more of the size of the substrate S.
For example, when the substrate S is disk-shaped and has a diameter of 100 mm, the substrate electrode 18 is preferably also disk-shaped, and preferably has a diameter of 80 to 98 mm.
If the substrate electrode 18 is too small with respect to the size of the substrate S, it is difficult to make the effect of the self-bias reflected on the surface of the substrate S uniform. Therefore, the thickness of the thin film formed on the substrate S The sheath film quality may be non-uniform. On the other hand, if the substrate electrode 18 is too close to another member (for example, the substrate holder 13), there is a possibility that electric power is discharged between the substrate holder 13 and the supplied sputtering power becomes unstable.
Therefore, when the size of the substrate electrode 18 is formed to be about 90% or more with respect to the size of the substrate S, the substrate electrode 18 side of the substrate holder 13 in the region approaching the substrate electrode 18 can be insulated. it can. Examples of the insulating means include an insulating coating by thermal spraying.

When the substrate electrode 18 is attached to the back side of each substrate S, power is supplied to each substrate electrode 18, so that it is not necessary to supply power to the entire substrate holder 13. Since the area to which current is applied is small, the range of voltage and current values that can be applied to each substrate S can be set to a higher value than before, and the ion density can be increased. Or shortening the processing time.

A sputtering source and a plasma source 80 are arranged around the substrate holder 13 arranged in the vacuum vessel 11. In this example, two sputter sources and one plasma source 80 are provided. However, in the present invention, at least one sputter source is sufficient, and according to this, there is at least one film formation region described later. That's fine.

In this example, film formation regions 20 and 40 are formed on the front surface of each sputtering source. Similarly, a reaction region 60 is formed on the front surface of the plasma source 80.
The regions 20 and 40 are formed by the inner wall surface of the vacuum vessel 11, the partition wall 12 (or 14) protruding from the inner wall surface toward the substrate holder 13, the outer peripheral surface of the substrate holder 13, and the front surface of each sputtering source. As a result, the regions 20 and 40 are separated from each other spatially and pressurely inside the vacuum vessel 11, thereby ensuring independent spaces. FIG. 1 illustrates the case where two pairs of magnetron electrodes are provided (21a, 21b and 41a, 41b) on the assumption that two different types of materials are sputtered.
Similarly to the regions 20 and 40, the region 60 includes an inner wall surface of the vacuum vessel 11, a partition wall 16 protruding from the inner wall surface toward the substrate holder 13, an outer peripheral surface of the substrate holder 13, and a front surface of the plasma source 80. Thus, the region 60 is also spatially and pressure-separated from the regions 20 and 40 inside the vacuum vessel 11, and an independent space is secured. In this example, the processing in each of the regions 20, 40, 60 is configured to be independently controllable.

The configuration of each sputtering source is not particularly limited, but in this example, each sputtering source is configured as a dual cathode type including two magnetron sputtering electrodes 21a and 21b (or 41a and 41b). During film formation (described later), targets 29a and 29b (or 49a and 49b) are detachably held on the one end side surfaces of the electrodes 21a and 21b (or 41a and 41b), respectively. The other end of each electrode 21a, 21b (or 41a, 41b) is connected to an AC power source 23 (or 43) as power supply means via a transformer 24 (or 44) as power control means for adjusting the amount of power. Are connected to each of the electrodes 21a and 21b (or 41a and 41b) so that an AC voltage having a frequency of, for example, about 1 kHz to 100 kHz is applied.

A sputtering gas supply means is connected to the front surface (regions 20 and 40) of each sputtering source. In this example, the sputtering gas supply means includes a gas cylinder 26 (or 46) for storing the sputtering gas and a mass flow controller 25 (or 45) for adjusting the flow rate of the sputtering gas supplied from the cylinder 26 (or 46). ). Sputtering gas is introduced into each region 20 (or 40) through a pipe. The mass flow controller 25 (or 45) is a device that adjusts the flow rate of the sputtering gas. The sputtering gas from the cylinder 26 (or 46) is introduced into the region 20 (or 40) with the flow rate adjusted by the mass flow controller 25 (or 45).

The configuration of the plasma source 80 is not particularly limited, but in this example, the case body 81 fixed so as to block the opening formed in the wall surface of the vacuum vessel 11 from the outside, and the dielectric fixed to the front surface of the case body 81. And a body plate 83. The dielectric plate 83 is fixed to the case body 81 so that the antenna accommodating chamber 82 is formed in a region surrounded by the case body 81 and the dielectric plate 83.

The antenna accommodating chamber 82 is separated from the inside of the vacuum vessel 11. That is, the antenna accommodating chamber 82 and the inside of the vacuum container 11 form an independent space in a state of being partitioned by the dielectric plate 83. The antenna housing chamber 82 and the outside of the vacuum vessel 11 form an independent space in a state of being partitioned by the case body 81. The antenna housing chamber 82 communicates with the vacuum pump 15 via a pipe 15a, and by evacuating the vacuum pump 15, the inside of the antenna housing chamber 82 can be evacuated to a vacuum state.

In the antenna accommodating chamber 82, antennas 85a and 85b are installed. The antennas 85a and 85b are connected to an AC power supply 89 via a matching box 87 that houses a matching circuit. The antennas 85 a and 85 b are supplied with electric power from the AC power supply 89 to generate an induction electric field inside the vacuum vessel 11 (particularly, the region 60) and generate plasma in the region 60. In this example, an AC voltage is applied from the AC power supply 89 to the antennas 85 a and 85 b to generate plasma of the reaction processing gas in the region 60. A variable capacitor is provided in the matching box 87 so that the power supplied from the AC power supply 89 to the antennas 85a and 85b can be changed.

Reaction processing gas supply means is connected to the front surface (region 60) of the plasma source 80. In this example, the reaction processing gas supply means includes a gas cylinder 68 that stores the reaction processing gas, and a mass flow controller 67 that adjusts the flow rate of the reaction processing gas supplied from the cylinder 68. The reaction processing gas is introduced into the region 60 through a pipe. The mass flow controller 67 is a device that adjusts the flow rate of the reaction processing gas. The reaction processing gas from the cylinder 68 is introduced into the region 60 with the flow rate adjusted by the mass flow controller 67.
The reaction processing gas supply means is not limited to the above configuration (that is, a configuration including one cylinder and one mass flow controller), but includes a plurality of cylinders and a mass flow controller (for example, an inert gas and a reactive gas). Can be configured to include two gas cylinders that store the gas separately and two mass flow controllers that adjust the flow rate of each gas supplied from each cylinder.

Next, an example of the method of the present invention using the film forming apparatus 1 will be described.
(1) Preparation before film formation (a) First, the targets 29a and 29b (or 49a and 49b) are set on the electrodes 21a and 21b (or 41a and 41b), and the substrate holder 13 is used as a film formation target. After setting a plurality of substrates S, they are accommodated in the vacuum vessel 11.

As the substrate S, a plastic substrate (organic glass substrate), an inorganic substrate (inorganic glass substrate), or a metal substrate such as stainless steel is applicable, and the thickness thereof is, for example, 0.1 to 5 mm. Examples of the inorganic glass substrate as an example of the substrate S include soda lime glass (6H to 7H), borosilicate glass (6H to 7H), and the like. The numbers in parentheses on the inorganic glass substrate are pencil hardness values measured by a method according to JIS-K5600-5-4.
The arrangement of the substrate S is not particularly limited, but in this example, a plurality of the substrate S are intermittently arranged on the outer peripheral surface of the substrate holder 13 along the rotation direction (lateral direction) of the substrate holder 13, and the axis Z of the substrate holder 13 is A plurality of elements are intermittently arranged along a parallel direction (longitudinal direction, Y direction; equal to the vertical direction of the vacuum vessel 11).

The targets 29 a and 29 b (or 49 a and 49 b) are obtained by forming the film forming material to be formed on the substrate S into a flat plate shape (substantially rectangular plate shape), and the longitudinal direction thereof is the rotation axis Z of the substrate holder 13. The electrodes are held on the surfaces of the electrodes 21a and 21b (or 41a and 41b) so that the parallel surfaces are opposed to the side surfaces (or outer peripheral surfaces) of the substrate holder 13.
As a film forming material, for example, a metal such as Si, Nb, Al, Ta, or Cu, a non-metal such as C, or an insulator such as SiO ₂ , Nb ₂ O ₅ , or Al ₂ O ₃ is used as necessary. Can be selected as appropriate.

(B) Next, the inside of the vacuum vessel 11 is brought to a high vacuum state of about 10 ⁻⁵ to 0.1 Pa using the vacuum pump 15. At this time, the valve is opened and the antenna accommodating chamber of the plasma source 80 is exhausted at the same time. Thereafter, driving of the motor 17 is started, and the substrate holder 13 is rotated about the axis Z through the shaft //. Then, the substrate S held on the outer peripheral surface of the substrate holder 13 revolves around the axis Z, which is the rotation axis of the substrate holder 13, between the position facing the regions 20 and 40 and the position facing the region 60. Move repeatedly.

Then, the sputtering process performed in the regions 20 and 40 and the plasma exposure process performed in the region 60 are sequentially repeated to generate a thin film having a predetermined thickness on the surface of the substrate S.

In this example, the rotation speed of the substrate holder 13 may be 10 rpm or more, preferably 50 rpm or more, more preferably 80 rpm or more. By setting it to 50 rpm or more, merits such as densification of film quality and shortening of processing time increase, which is preferable. In this example, the upper limit of the rotation speed of the substrate holder 13 is, for example, about 150 rpm, preferably 100 rpm.

In this example, an intermediate thin film is formed on the surface of the substrate S by the sputtering process in any one of the areas 20 and 40, and the intermediate thin film is converted into an ultrathin film by the subsequent plasma exposure process. Then, by repeating the sputtering process and the plasma exposure process, the next ultrathin film is deposited on the ultrathin film, and this operation is repeated until the final thin film is obtained.

In this example, the “intermediate thin film” is a thin film formed by passing through either one of the region 20 and the region 40. “Ultra-thin film” is a term used to prevent confusion with this final “thin film” because an ultra-thin film is deposited multiple times to form a final thin film (thin film with a target thickness). In the sense that it is sufficiently thinner than the final “thin film”.

(2) Sputtering process The sputtering process is performed as follows. In this example, first, after confirming the stability of the pressure in the vacuum vessel 11, the pressure in the region 20 is adjusted to, for example, 0.05 to 0.2 Pa, and then the predetermined flow rate from the gas cylinder 26 via the mass flow controller 25. The sputtering gas is introduced into the region 20.

In this example, an inert gas is used alone as a sputtering gas, and no reactive gas such as nitrogen or oxygen is used in combination. The flow rate of the inert gas introduced in this example is, for example, about 100 to 600 sccm, preferably about 150 to 500 sccm. Then, the periphery of the targets 29a and 29b becomes an inert gas atmosphere. In this state, an AC voltage is applied from the AC power source 23 to the electrodes 21a and 21b via the transformer 24, and an alternating electric field is applied to the targets 29a and 29b.

In the present example, and it supplies the target 29a, against 29 b, as the sputtering power density is ^{0.57W / cm 2 ~ 10.91W / cm} 2 or so, the electrodes 21a, 21b to the power (sputtering power). “Power density” means power (W) supplied per unit area (cm ² ) of the targets 29a, 29b (or 49a, 49b).

By supplying electric power to the targets 29a and 29b, the target 29a becomes a cathode (negative pole) at a certain point in time, and at that time, the target 29b always becomes an anode (positive pole). When the direction of the alternating current changes at the next time point, the target 29b becomes the cathode (minus pole) and the target 29a becomes the anode (plus pole). In this way, the pair of targets 29a and 29b alternately become an anode and a cathode, so that a part of the sputtering gas (inert gas) around each target 29a and 29b emits electrons and is ionized. A leakage magnetic field is formed on the surfaces of the targets 29a and 29b by the magnets disposed on the electrodes 21a and 21b, so that the electrons draw a toroidal curve in the magnetic field generated near the surfaces of the targets 29a and 29b. Go around. A strong sputtering plasma is generated in the region 20 along the electron trajectory, and ions of the sputtering gas in the plasma are accelerated toward the target in the negative potential state (cathode side) and collide with the targets 29a and 29b. As a result, the surfaces (surfaces to be sputtered) of the targets 29a and 29b are sputtered to release atoms and particles (hereinafter sometimes collectively referred to as sputtered particles or target material) (sputtering process).

During sputtering, non-conductive or poorly conductive incomplete reactants may adhere on the anode, but when this anode is converted to a cathode by an alternating electric field, these Incomplete reactants and the like are sputtered, and the target surface becomes the original clean state. Then, by repeating the pair of targets 29a and 29b alternately becoming an anode and a cathode, a stable anode potential state is always obtained, and a change in the plasma potential (almost equal to the normal anode potential) is prevented, and the substrate The sputtered particles are stably emitted toward the surface of S.

In this example, power (for example, 50 to 2000 W for high-frequency power, for example, 1000 V or less, preferably 30 to 1000 V for DC power) is supplied from the power supply source 19 to each substrate electrode 18 during the above-described sputtering process. Then, a voltage is applied to each substrate S. Thus, a potential is applied to the substrate plasma 18 with respect to the sputtering plasma, whereby a part of all ions of the sputtering gas existing in the sputtering plasma are attracted to and collide with the substrate S side. Energy is applied to the deposited and deposited target material (plasma treatment).

In this example, it is preferable to supply power to the substrate electrode 18 so that the voltage applied to each substrate S is 5 to 1000V. When this voltage is 5 V or more, merits such as densification of film quality and shortening of processing time are easily obtained. The voltage here can be 1000 V or less. Note that the voltage here means an output voltage when based on the power supplied from the DC power source, and a self-bias voltage (a negative bias generated during RF plasma discharge) when based on the power supplied from the RF power source. DC voltage).
The voltage applied to each substrate S is desirably kept at a predetermined value without being changed during film formation.
The above is the sputtering process performed in the region 20 (deposition process by the bias sputtering method for forming the intermediate thin film while applying both the cathode voltage and the substrate bias voltage).

(3) Plasma treatment Plasma treatment is performed as follows. In this example, the operation of the region 60 is started together with the operation of the regions 20 and 40. Specifically, a predetermined amount of reaction processing gas is introduced into the region 60 from the gas cylinder 68 via the mass flow controller 67, and the surroundings of the antennas 85a and 85b are set to a predetermined gas atmosphere.

The pressure in the region 60 is maintained at 0.07 to 1 Pa, for example. Further, at least during the generation of plasma in the region 60, the internal pressure of the antenna housing chamber is maintained at 0.001 Pa or less. When an AC voltage having a frequency of 10 kHz to 2.5 GHz (preferably 100 kHz to 1000 MHz) is applied to the antennas 85 a and 85 b from the AC power supply 89 with the reaction processing gas introduced from the cylinder 68, the antenna in the region 60 is used. Plasma is generated in regions facing 85a and 85b. This plasma is a plasma different from the sputtering plasma generated in the regions 20 and 40.

The power (plasma processing power) supplied from the AC power source 89 is preferably 0.5 to 4.5 kW when the substrate S is made of a glass material, and when the substrate S is made of a resin material. , Preferably 1 kW or less.

The reaction processing gas to be introduced may be an inert gas and / or a reactive gas, and preferably depends on the type of thin film to be formed. For example, when the targets 29a and 29b are made of carbon (C) and a DLC (Diamond-Like Carbon) thin film is formed, an inert gas (such as argon or helium) can be used. When the targets 29a and 29b are made of silicon (Si) and a SiO ₂ thin film is formed, at least one containing a reactive gas (reactive gas alone or a mixed gas of an inert gas and a reactive gas) should be used. Can do.
As the reactive gas, an oxidizing gas such as oxygen or ozone, a nitriding gas such as nitrogen, a carbonizing gas such as methane, or a fluorinated gas such as CF ₄ can be used.

In this example, when the substrate holder 13 is rotated and each substrate S is introduced into the region 60, a voltage is applied to each substrate S as in the region 20. Therefore, similarly to the above, a potential is applied to the substrate electrode 18 with respect to the plasma different from the sputtering plasma, so that the ions of the reaction processing gas existing in the plasma different from the sputtering plasma are on the substrate S side. The intermediate thin film formed on the surface of the substrate S is further given energy (plasma reprocessing).

It should be noted that the voltage applied to each substrate S is desirably kept at a predetermined value from start to finish even after the substrate S is introduced into the region 60. However, the amount of power supplied to the substrate electrode 18 may be varied so that the applied voltage is slowed up at 1000 V / second or less at the timing of applying the voltage.

When a reactive gas (for example, oxygen gas) is included in the reaction processing gas to be introduced, active species of the reactive gas exist in the plasma, and this is led to the region 60. Then, when the substrate holder 13 is rotated and the substrate S is introduced into the region 60, an intermediate thin film (for example, a metal atom or an incomplete oxide of this metal atom) formed on the surface of the substrate S in the regions 20 and 40. Is exposed to plasma (oxidation treatment) and converted into a complete oxide of metal atoms to form an ultra-thin film.
The above is the plasma exposure to the intermediate thin film in the region 60.

In this example, the sputtering process and the plasma exposure process are repeated until the ultrathin film formed on the surface of the substrate S has a predetermined film thickness (for example, about 3 μm or more, preferably about 3 to 7 μm). A final thin film having a thickness to be formed is generated on all the substrates S held by the substrate holder 13.

According to this example, after the film formation by the conventional bias sputtering method is performed in the film formation region 20 formed in the single vacuum vessel 11, the film formation region 20 is arranged spatially separated. Plasma reprocessing is performed in which ions in the plasma different from the sputtering plasma generated in the reaction region 60 and collided with ions in the plasma are collided. That is, plasma treatment is again performed on the thin film after bias sputtering. Thus, the effect of the plasma treatment can be independently controlled by changing the processing conditions in the region 60 without increasing the voltage applied to the substrate S or the sputtering power in the region 20.

(4) Other Embodiments The embodiments described above are described for facilitating understanding of the invention, and are not described for limiting the invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the above invention.

In the above-described embodiment, after a final thin film having a target film thickness is formed on the substrate S, plasma post-treatment may be further performed. Specifically, first, the rotation of the substrate holder 13 is temporarily stopped, and the operations in the regions 20 and 40 (supply of sputtering gas and supply of power from the AC power sources 23 and 43) are stopped. On the other hand, the operation of the region 60 is continued as it is. That is, in the region 60, the supply of the reaction processing gas and the supply of electric power from the AC power supply 89 are continued to continue generating plasma. In this state, when the substrate holder 13 is rotated again and the substrate S is transported to the region 60, the thin film formed on the substrate S is subjected to plasma processing while passing through the region 60 (post-processing). By performing the plasma post-treatment, it is possible to expect effects such as improved surface flatness on the final thin film.
In the case of performing the plasma post-treatment, the plasma exposure treatment when forming the thin film and the plasma post-treatment after forming the thin film may be performed under the same conditions or under different conditions. In the case of performing the plasma post-treatment, for example, the concentration of the reactive gas in the mixed gas may be changed. In the case of performing the plasma post-treatment, the plasma processing power (power supplied from the AC power supply 89) may be varied with respect to the plasma exposure processing when forming the thin film. In this case, the matching box 87 can be used for adjustment. The plasma post-treatment time is set to an appropriate time within a range of about 1 to 60 minutes, for example.

In the above-described embodiment, the thin film is formed using the magnetron sputtering film forming apparatus 1 which is an example of sputtering. However, the present invention is not limited to this, and other methods such as bipolar sputtering using no magnetron discharge are used. It is also possible to form a film by another sputtering method using a known film forming apparatus for performing sputtering. However, the atmosphere during sputtering is an inert gas atmosphere in any case.

Next, examples that more specifically embody the above-described embodiment of the present invention will be given to describe the invention in more detail.

[Experimental Example 1]
1 and FIG. 2 are used, 100 substrates S are set on the substrate holder 13, and sputtering in the region 20 and plasma exposure in the region 60 are repeated under the following conditions, and the thickness of 3 μm. A plurality of experimental samples in which a DLC thin film was formed on the substrate S were obtained.
The film hardness after film formation was evaluated under the following conditions. The results are shown in FIG.

・ Substrate S: BK7 (glass substrate)
-Film formation rate: 0.1 nm / s,
-Substrate temperature: room temperature.

<Sputtering in region 20>
・ Sputtering gas: Ar,
・ Gas pressure for sputtering: 0.11 Pa,
-Sputtering gas introduction flow rate: 80 sccm,
-Targets 29a and 29b: carbon (C),
Sputtering power density: 10.91 W / cm ²
-Voltage applied to the substrate S: 180V,
A power supply source to the substrate electrode 18: DC power source.

<Plasma exposure in region 60>
Reaction reaction gas: Ar,
-Gas pressure for reaction treatment: 0.11 Pa,
・ Reaction treatment gas introduction flow rate: 60 sccm,
Power supplied from the AC power supply 89 to the antennas 85a and 85b (plasma processing power): 0 W, 400 W, 500 W, 600 W, 800 W, 1000 W, 2500 W, 5000 W,
The frequency of the alternating voltage applied to the antennas 85a and 85b: 13.56 MHz.

<Film hardness>
Using a microhardness tester (MMT-X7, manufactured by Matsuzawa), the hardness (GPa) of the DLC thin film surface of the experimental example sample was measured under the following measurement conditions.
Indenter shape: Vickers indenter (a = 136 °),
・ Measurement environment: temperature 20 ℃, relative humidity 60%,
-Test load: 25 gf
・ Loading speed: 10μ / s,
Maximum load creep time: 15 seconds.

<Discussion>
From FIG. 3, the film hardness of the DLC thin film of the experimental example sample changed depending on the plasma processing power in the region 60. As a result, the sputtering power density in the region 20 and the substrate bias supply power in the region 20 and the region 60 are made constant, and only the plasma processing power in the region 60 is changed to adjust the film hardness of the thin film obtained. Can understand (control).

[Experiment 2]
Using the film forming apparatus 1 shown in FIGS. 1 and 2, 36 substrates S are set on the substrate holder 13, and sputtering in the region 20 and plasma exposure in the region 60 are repeated under the following conditions, and the thickness is 1 μm. A plurality of experimental example samples in which a SiO ₂ thin film was formed on a substrate S were obtained.
The etching rate after plasma film formation was evaluated under the following conditions. The results are shown in FIG.

・ Substrate S: BK7 (glass substrate)
-Film formation rate: 0.1 nm / s,
-Substrate temperature: room temperature.

<Sputtering in region 20>
・ Sputtering gas: Ar,
・ Gas pressure for sputtering: 0.1 Pa
-Sputtering gas introduction flow rate: 80 sccm,
Targets 29a and 29b: silicon (Si)
Sputtering power density: 5.74 W / cm ²
-Voltage applied to the substrate S: 130V
-Power supplied to the substrate electrode 18 (substrate bias supply power): 600 W
-Power supply source to substrate electrode 18: RF power source + DC power source

<Plasma exposure in region 60>
Reaction reaction gas: O ₂
· _{O 2} concentration in the reaction process for gas: 100%,
-Gas pressure for reaction treatment: 0.1 Pa,
・ Reaction treatment gas introduction flow rate: 50 sccm,
Power supplied from the AC power supply 89 to the antennas 85a and 85b (plasma processing power): 2 kW, 3 kW, 4 kW, 4.5 kW,
The frequency of the alternating voltage applied to the antennas 85a and 85b: 13.56 MHz.

<Etching rate>
After calculating the film-forming rate in a state where no voltage is applied to each substrate S (no bias. Voltage applied to the substrate S: 0 V, substrate bias supply power: 0 W), The etching rate (nm / S) of the SiO ₂ thin film was evaluated.
(Calculation formula)
Etching rate = (deposition rate without bias)-(deposition rate with bias)

In the regions 20 and 60, both ions in the sputtering plasma and ions in a plasma different from the sputtering plasma are attracted to each substrate S side by the voltage applied to each substrate S and collide with the thin film. The film that could not become a dense structure is formed while being etched. After film formation, the film formation rate (with bias) can be calculated by measuring the film thickness of the thin film.

<Discussion>
From FIG. 4, the etching rate of the SiO ₂ thin film of the experimental example sample changed depending on the plasma processing power in the region 60. Thereby, the sputtering power density in the region 20 and the substrate bias supply power in the region 20 and the region 60 are made constant, and only the plasma processing power in the region 60 is changed to adjust the etching rate of the obtained thin film. Can understand (control).

As a result, in step coverage (covered state with fine stepped portions), the film forming rate of the side surface portion and the bottom portion in the stepped portion can be controlled. For example, as shown in FIG. obtain.

Claims (10)

1. A plurality of substrates to which a voltage is applied are sequentially introduced into a predetermined position in a film formation region where sputtered particles emitted from a target reach by sputtering plasma due to sputter discharge, whereby sputtered particles are formed on the surface of the substrate. In a film forming method for forming a thin film by performing a plasma treatment that causes ions in the sputtering plasma to collide with the substrate or a deposit of sputtered particles while depositing and reaching.
   An intermediate thin film is formed by depositing sputtered particles and performing plasma treatment with sputtering plasma in a film formation region formed in a single vacuum chamber having an exhaust system, and then spatially separating the film formation region. A film forming method, wherein the substrate is moved into a reaction region arranged, and plasma reprocessing is performed by causing ions in plasma different from sputtering plasma to collide with the intermediate thin film, thereby forming the thin film.
2. In the film-forming method of Claim 1,
   The film formation area where sputtered particles are released from the target by sputtering plasma by sputtering discharge and the reaction area where plasma other than sputtering plasma is generated are spatially separated in a single vacuum chamber having an exhaust system. In a film forming method for forming a thin film on each surface of a plurality of substrates, using a film forming apparatus configured to be independently controllable in each region,
   Generating a sputtering plasma by sputtering discharge in the film formation region;
   Generating a plasma in the reaction region different from the sputtering plasma;
   Applying a voltage to each of the plurality of substrates;
   A predetermined position in a film formation region where sputtered particles emitted from a target reach a plurality of substrates to which a voltage is applied and a predetermined position in a reaction region exposed to a plasma different from the sputtering plasma And a step of moving between
   Sputtered particles emitted from the target reach and deposit on the substrate introduced into the deposition area, and at the same time, plasma treatment is performed to cause ions in the sputtering plasma to collide with the substrate or deposits of sputtered particles to form an intermediate thin film Then, a thin film is formed by performing plasma reprocessing on the intermediate thin film of the substrate that has moved to the reaction region to cause ions in the plasma different from the sputtering plasma to collide with each other.
3. In the film formation region, a target made of metal is sputtered under an atmosphere of working gas, a sputtered particle is deposited and plasma treatment is performed by sputtering plasma, and a continuous intermediate thin film made of metal or an incomplete reaction product of metal or discontinuous. An intermediate thin film of
   In the reaction region, the active species of the electrically neutral reactive gas in the plasma generated in the atmosphere containing the reactive gas is brought into contact with the intermediate thin film of the substrate that has moved to react, and the complete reaction of the metal. 3. The film forming method according to claim 1, wherein the film is converted into a continuous ultrathin film made of a reactant.
4. An inert gas is introduced into the film formation region as an operating gas, and an inert gas ionized in the sputtering plasma is generated. In the reaction region, the inert gas, the reactive gas, and the inert gas and the reactive gas are generated. The film forming method according to any one of claims 1 to 3, wherein any one of the mixed gas is introduced to produce an ionized gas in a plasma different from the sputtering plasma. .
5. By rotating a cylindrical substrate holder while applying a voltage while holding a plurality of substrates on the outer peripheral surface, the plurality of substrates to which a voltage is applied are moved to the predetermined position in the film formation region and the reaction region in the reaction region. 5. The film forming method according to claim 1, wherein the thin film is formed by moving between a predetermined position and repeating the formation of the intermediate thin film and the conversion to the ultra thin film.
6. 6. The power supply source for applying a voltage to a plurality of substrates is a power supply source configured to be connectable to one or both of a DC power source and a high frequency power source. The film forming method.
7. The voltage applied to each of the plurality of substrates (output voltage when based on power supplied from a DC power supply, and self-bias voltage when based on power supplied from a high-frequency power supply) is 5 to 1000 V. The film forming method according to claim 6.
8. 8. The film forming method according to claim 1, wherein plasma is generated in the reaction region by applying an AC voltage having a frequency of 10 kHz to 2.5 GHz from an AC power source.
9. A vacuum chamber having an exhaust system;
   A film formation region formed in the vacuum chamber;
   A reaction region formed in the vacuum chamber and spatially separated from the film formation region;
   A cathode electrode on which the target is mounted;
   A sputtering power source for generating a sputter discharge in a film formation region facing the target surface to be sputtered;
   Plasma generating means for generating in the reaction region a plasma different from the sputtering plasma generated by the sputter discharge generated in the film formation region;
   A cylindrical substrate holder for holding a plurality of substrates on the outer peripheral surface;
   Driving means for rotating the substrate holder,
   By rotating the substrate holder by the driving means, a predetermined position in the film formation region where the sputtered particles emitted from the target by the sputtering plasma reach, and a predetermined position in the reaction region exposed to plasma different from the sputtering plasma In the film forming apparatus in which the substrate is repeatedly moved between
   A substrate electrode for mounting the substrate held by the substrate holder from the back surface;
   A bias power supply for supplying power to the substrate electrode;
   The target is mounted on the cathode electrode, the sputtering power supply is turned on, the plasma generating means is operated, the plurality of substrates are held on the outer peripheral surface of the substrate holder, and the substrate electrode is supplied with power and applying a voltage to the substrate. Plasma that causes the sputtered particles emitted from the target to reach and deposit on the substrate that has moved to the film-forming region by rotating the holder, and at the same time, causes the ions in the sputtering plasma to collide with the substrate or deposits of sputtered particles After processing to form the intermediate thin film, the intermediate thin film of the substrate that has moved to the reaction region is subjected to plasma reprocessing that causes ions in the plasma different from the sputtering plasma to collide, and then converted to an ultra thin film, A film forming apparatus configured to form a thin film by laminating a plurality of the ultra thin films.
10. A vacuum chamber having an exhaust system;
    A film formation region formed in the vacuum chamber;
    A reaction region formed in the vacuum chamber and spatially separated from the film formation region;
    A cathode electrode on which the target is mounted;
    A sputtering power source for generating a sputter discharge in a film formation region facing the target surface to be sputtered;
    Plasma generating means for generating in the reaction region a plasma different from the sputtering plasma generated by the sputter discharge generated in the film formation region;
    A cylindrical substrate holder for holding a plurality of substrates on the outer peripheral surface;
    Driving means for rotating the substrate holder,
    By rotating the substrate holder by the driving means, a predetermined position in the film formation region where the sputtered particles emitted from the target by the sputtering plasma reach, and a predetermined position in the reaction region exposed to plasma different from the sputtering plasma In the film forming apparatus in which the substrate is repeatedly moved between
    A substrate electrode for mounting the substrate held by the substrate holder from the back surface;
    A film forming apparatus further comprising a bias power source for supplying power to the substrate electrode.

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