JP6533511B2 - Film forming method and film forming apparatus - Google Patents

Description

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

  In addition to the cathode electrode on which the target is placed, a potential is applied to the substrate electrode on which the substrate is placed as one of the sputter deposition methods which is a kind of film deposition method using plasma reaction, and the substrate electrode is placed on the substrate electrode. There is known a method (bias sputtering method) of forming a thin film while applying a bias voltage to a placed substrate (patent documents 1 and 2).

  The principle of this bias sputtering method is roughly as follows. After an atmosphere gas such as a rare gas is introduced into the system, 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. A part of the total ions generated in the plasma generated by the discharge is attracted to the target and collides, repels the target material, and consists of a deposit of the target material on the surface of the substrate placed opposite to the target. Form a thin film (sputter deposition). At the same time, by supplying power to the substrate electrode on which the substrate is mounted, a potential is applied to the substrate electrode to the substrate electrode, whereby the remainder of all the ions present in the plasma is attracted to the substrate. The collision causes the target material deposited on the substrate to receive energy (plasma treatment), thereby giving the thin film a predetermined function.

  As a function imparted by plasma treatment, for example, the film quality is densified to improve the hardness (Patent Document 1), and the step coverage (the covering state at the fine step portion) is improved, that is, the side surface at the step portion Both the bottom and the bottom have a substantially uniform film thickness (Patent Document 2). The former is due to film formation assistance by ions in plasma, and the latter is due to the etching effect by the same ions.

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

  All the conventional film forming methods by bias sputtering including the methods disclosed in Patent Documents 1 and 2 sputter-deposited ions generated in a single plasma generated between the cathode electrode and the substrate electrode. And plasma treatment. From another point of view, sputter deposition and plasma processing are performed in the same region. Therefore, there is a problem in that the controllability is low.

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

  However, according to the method of 1), the energy of the substrate is increased along with the density of the ions irradiated to the substrate, so the substrate may be damaged (damaged) depending on the material of the used substrate. According to the method of 2), the density of ions colliding with the target is increased, thereby increasing the amount of target material sputtered from the target (increasing the film forming rate), so that the desired film forming rate can be maintained. It disappears.

  In one aspect of the present invention, there is provided a film formation method and a film formation apparatus by bias sputtering which can adjust the effect of plasma processing while maintaining a desired film formation 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 to predetermined positions in a film formation region to which sputtered particles emitted from a target by sputtering plasma by sputtering discharge reach. A film forming method for forming a thin film by performing plasma processing in which sputtered particles reach and deposit on the surface and ions in the sputtering plasma are caused to collide with a substrate or a deposit of sputtered particles.
After an intermediate thin film is formed by deposition of sputtered particles and plasma processing by sputtering plasma in a film formation region formed in a single vacuum tank having an exhaust system, the film is separated spatially from the film formation region. The substrate is moved within the reaction area (that is, from the film formation area to the reaction area), and the intermediate thin film is subjected to plasma reprocessing in which ions in plasma other than sputtering plasma are collided to form the thin film. A film forming method is provided.

  In the above invention, the film formation area for releasing sputtered particles from the target by sputtering plasma by sputtering discharge and the reaction area for generating plasma different from sputtering plasma are each space in a single vacuum chamber having an exhaust system. It can implement | achieve by using the film-forming apparatus arrange | positioned separately, and the process in each area | region was comprised independently and was comprised so that control was possible.

Specifically, a film forming method for forming a thin film on each surface of a plurality of substrates using the film forming apparatus as an example,
Generating a sputtering plasma by sputtering discharge in a film formation region;
Generating a plasma other than sputtering plasma in the reaction region;
Applying a voltage to each of the plurality of substrates;
A plurality of substrates to which a voltage is applied is at least a predetermined position in a reaction region exposed to a plasma different from the sputtering plasma from a predetermined position in the film formation region reached by the sputtered particles emitted from the target by the sputtering plasma. Moving to a position, and
An intermediate thin film is formed by causing plasma processing to cause ions in the sputtering plasma to collide with the substrate or a deposit of sputtered particles while causing sputtered particles emitted from the target to reach and deposit on the substrate introduced into the film formation region. After the formation, the intermediate thin film of the substrate which has moved to the reaction region is subjected to plasma reprocessing in which ions in plasma other than sputtering plasma are collided to form a thin film. Be done.

  In the above invention, the formation of the intermediate thin film and the plasma reprocessing in forming the thin film may be performed at least once. Preferably, a thin film having a target film 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 formation region, the target made of metal is sputtered under the atmosphere of the working gas, the deposition of sputtered particles and the plasma treatment by sputtering plasma are performed, and the metal or the incomplete intermediate made of metal incompletely reacted A thin film or a discontinuous intermediate thin film is formed, and in the reaction zone, the active species of the electrically neutral reactive gas in the plasma generated under the atmosphere containing the reactive gas is transferred to the middle of the substrate which has moved. A thin film can be brought into contact and reacted, and the film can be converted into a continuous ultrathin film consisting of complete reaction products of metals.

  In the above invention, an inert gas is introduced into the film formation region as an operating gas to generate an ionized inert gas in the sputtering plasma, and an inert gas, a reactive gas and an inert gas are produced in the reaction region. It is also possible to introduce either of the mixed gas of and the reactive gas, and generate the ionized introduced gas in a plasma other than the sputtering plasma.

  In the above invention, by holding the plurality of substrates on the outer peripheral surface and rotating the cylindrical substrate holder while applying the voltage, the plurality of substrates to which the voltage is applied are reacted with the predetermined position of the film formation region. It is possible to form a thin film by moving it to 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, one configured to be connectable 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 (the output voltage when based on the power supplied from the DC power supply, and the self bias voltage when based on the power supplied from the high frequency power supply) is 5 to 1000 V be able to.

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

As an example of realizing formation of an intermediate thin film and film conversion to an ultra thin film a plurality of times, for example, a film forming apparatus having the following configuration can be used.
According to the invention, a vacuum chamber having an exhaust system,
A deposition region formed in a 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 sputtering discharge in a film formation area facing the target sputtering surface;
Plasma generating means for generating plasma other than sputtering plasma by sputtering discharge generated in the film formation region in the reaction region;
A cylindrical substrate holder for holding a plurality of substrates on the outer peripheral surface;
Drive means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region to which 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 on which the substrate held by the substrate holder is mounted from the back;
There is provided a film forming apparatus further comprising a bias power supply for supplying power to a substrate electrode.

  In the above-described invention, the film forming apparatus mounts the target on the cathode electrode and 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 electrodes. By rotating the substrate holder while applying a voltage to the substrate, sputter particles emitted from the target reach and deposit on the substrate moved to the film formation region, and at the same time, ions in the sputtering plasma are Alternatively, after forming an intermediate thin film by performing plasma processing to collide with a deposit of sputtered particles and forming an intermediate thin film, plasma reprocessing is performed to collide ions in the plasma different from sputtering plasma to the intermediate thin film of the substrate moved to the reaction area. So as to form a thin film by laminating a plurality of such thin films. It can be formed.

  The term "movement" in the above invention includes linear movement as well as curvilinear movement (e.g., circumferential movement). Therefore, “moving the substrate from the film formation region to the reaction region” includes not only the aspect of revolving around a certain central axis, but also the aspect of reciprocating on the linear trajectory connecting certain two points.

  The term "rotation" in the above invention includes revolution as well as rotation. Therefore, simply saying "rotate around the central axis" includes the aspect of revolving in addition to the aspect of rotating around a certain central axis.

  The "intermediate thin film" as referred to in the above invention is a film formed by passing through the film formation region. Also, "ultrathin film" is a term used to prevent confusion with this "thin film" because the ultra thin film is deposited multiple times to become the final thin film, and from the final "thin film" It means that it is thin enough.

According to the invention, after film formation is performed by the conventional bias sputtering method in the film formation region formed in a single vacuum chamber, the film formation region is spatially separated from the film formation region. Plasma reprocessing is performed in which ions in plasma other than sputtering plasma in the deposition region generated in the reaction region collide with each other. That is, the thin film after bias sputtering is subjected to plasma treatment again. As a result, the effect of the plasma processing can be independently controlled without raising the voltage applied to the substrate or the sputtering power.
That is, according to the present invention, the effect of plasma processing 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 the line II-II of 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 embedded film formation on a patterned 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 ... film formation 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),
Reference Signs List 60 reaction area 80 plasma source 81 case body 82 antenna accommodation chamber 83 dielectric plate 85a, 85b antenna 87 matching box 89 AC power supply for reaction processing gas supply means (68 ... gas cylinder for reaction processing, 67 ... mass flow controller).

Hereinafter, an embodiment of the method of the present invention will be described in detail according to the attached drawings.
First, one configuration example of a film forming apparatus capable of realizing the method of the present invention will be described.

The film forming apparatus 1 shown in FIGS. 1 and 2 is an example of the film forming apparatus of the present invention, and is a so-called carousel type apparatus of a batch system capable of forming a film on a plurality of substrates S in one processing. The vacuum vessel 11 is provided, and a cylindrical rotating body is disposed in the vacuum vessel 11.
The vacuum vessel 11 is a side wall extending in the vertical direction (the paper surface direction of FIG. 1 and the vertical direction of FIG. 2. The same applies hereinafter) in this example, and is a plane direction (direction perpendicular to the vertical direction). It has a chamber main body configured to surround the paper surface direction of 2. The same applies hereinafter. In this example, the cross section in the plane direction of the chamber main body is rectangular, but may be another shape (for example, circular or the like). The vacuum vessel 11 is made of, for example, a metal such as stainless steel.

  The vacuum vessel 11 has a hole for penetrating the shaft 15 (see FIG. 2) at the upper side, and is electrically grounded to be at the 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 in the vacuum vessel 11 can be adjusted by the vacuum pump 15 and a controller (not shown). The vacuum pump 15 can be configured by, for example, a rotary pump or a turbo molecular pump (TMP).

  The shaft 15 is formed of a substantially pipe-like member in this example, and is rotated relative to the vacuum vessel 11 through an insulating member (not shown) disposed in a hole formed above the vacuum vessel 11. It is supported possible. The shaft 15 is rotatable relative to the vacuum vessel 11 in a state where the shaft 15 is electrically insulated from the vacuum vessel 11 by supporting the vacuum vessel 11 via an insulating member made of insulator, resin or the like. .

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

  The rotary drum is disposed in the vacuum vessel 11 so that an axis Z extending in the cylinder direction in this example is directed in the vertical direction (Y direction) of the vacuum vessel 11. The rotary drum has a cylindrical shape in this example, but the present invention is not limited to this shape, and the cross section may have a polygonal columnar shape or a conical shape. The rotating drum rotates about the axis Z through the rotation of the shaft 15 by the drive of the motor 17.

  The substrate holder 13 is attached to the outer side (outer periphery) of the rotating drum. On the outer peripheral surface of the substrate holder 13, a plurality of substrate holding parts (for example, concave parts, not shown) are provided, and a plurality of the substrates S as film formation targets are provided by the substrate holding parts. It means support from the opposite side. In this example, the axis (not shown) of the substrate holder 13 and the axis Z of the rotating drum coincide with each other. Therefore, by rotating the rotary drum about the axis Z, the substrate holder 13 rotates in synchronization with the rotation, integrally with the rotary drum, and rotates around the axis Z of the drum.

Each of the plurality of substrate holding portions provided on the outer peripheral surface of the substrate holder 13 is equipped with a substrate electrode 18 on which the substrate S is mounted from the back surface. Each substrate electrode 18 is formed of, for example, a plate-like member made of stainless steel, and is connected to the power supply source 19 provided outside the vacuum vessel 11 through the wiring member 19 a.
The power supply source 19 is configured to be connectable to one or both of a direct current (DC) power supply and a radio frequency (RF) power supply in this example (detailed structure is not shown). When forming a film on the insulating substrate S, or when using an insulator as a film forming material to be attached to the substrate S, it is possible to use only an RF power supply or a combination of an RF power supply and a DC power supply. When depositing a conductive film-forming material on the conductive substrate S, it is possible to use only a DC power supply or a combination of an RF power supply and a DC power supply.

In this example, a filter (not shown) may be connected in series between the substrate electrode 18 and the DC power supply. By doing this, it becomes possible to effectively flow the high frequency power from the RF power supply in the direction of the substrate electrode 18 without flowing it to the DC power supply (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 supply.
In the present embodiment, the wiring member 19a passes from the power supply side which is the outside of the vacuum vessel 11 to the inside of the rotating drum disposed in the vacuum vessel 11 through the inside of the shaft 15 which is formed of a substantially pipe-like member. It has an extended shape.

  Each substrate electrode 18 is disposed in parallel to be opposite to the back surface of each substrate S at a position separated by a predetermined distance (d) from the back surface of each substrate S to be disposed. 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 where the effect of self bias by the substrate electrode 18 is reflected on the substrate S It is set. Further, 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.

  Although depending on the film forming conditions, in this example, the effect of the self bias by the substrate electrode 18 affects the substrate S when the distance d is about 0.20 mm or less. As a result of conducting film forming experiments while changing film forming 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 forming atmosphere, the distance d is 0.10 to 0.1. A good film was obtained within the range of 14 mm. Therefore, it is preferable to set the distance d in the range. Further, 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 the present embodiment, the distance d is adjusted for each substrate electrode 18, but the distance d can be set collectively by configuring the substrate electrodes 18 integrally.

The size of each substrate electrode 18 is determined in consideration of the size of each substrate S. The size of 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 the diameter thereof is 100 mm, the substrate electrode 18 is desirably disk-shaped as well, and is preferably formed with a diameter of 80 to 98 mm.
If the substrate electrode 18 is too small relative to the size of the substrate S, it becomes difficult to make the self-bias effect reflected on the surface of the substrate S uniform, so the thickness of the thin film formed on the substrate S The sheath film quality may be uneven. On the other hand, if the substrate electrode 18 approaches too close to another member (for example, the substrate holder 13 or the like), the substrate electrode 13 may be discharged from the substrate holder 13 and the supplied sputtering power may become unstable.
For this reason, when the size of the substrate electrode 18 is formed to be about 90% or more of the size of the substrate S, the substrate electrode 18 side of the substrate holder 13 in the region approaching the substrate electrode 18 may be insulated. it can. As an insulation means, the insulating coating by thermal spraying etc. is mentioned, for example.

  When the substrate electrodes 18 are attached to the back surface side of the respective substrates S, power is supplied to the respective substrate electrodes 18, so it is not necessary to supply power to the entire substrate holder 13. Since the area to which current is applied is small, the voltage / current value range that can be applied to each substrate S can be set to a higher value than in the past to increase the ion density, and as a result, the film quality becomes finer Or processing time can be shortened.

  A sputter source and a plasma source 80 are disposed around the substrate holder 13 disposed in the vacuum chamber 11. In the present embodiment, two sputtering sources and one plasma source 80 are provided, but in the present invention, at least one sputtering source is required, and according to this, at least one film forming region to be described later is Just do it.

In the present embodiment, film formation regions 20 and 40 are formed on the front surface of each sputtering source. Similarly, on the front surface of the plasma source 80, a reaction area 60 is formed.
The regions 20 and 40 are formed by the inner wall surface of the vacuum vessel 11, the partition wall 12 (or 14) projecting 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. The regions 20 and 40 are separated in space and pressure in the interior of the vacuum vessel 11, respectively, and independent spaces are secured in each of the regions 20 and 40. Note that FIG. 1 exemplifies the case where two pairs of magnetron electrodes are provided (21a, 21b and 41a, 41b) on the assumption that two different types of substances are sputtered.
Similarly to the regions 20 and 40, the region 60 also includes the inner wall surface of the vacuum vessel 11, the partition wall 16 projecting from the inner wall surface toward the substrate holder 13, the outer peripheral surface of the substrate holder 13, and the front surface of the plasma source 80. Thus, the region 60 is also spatially and pressurely separated from the regions 20 and 40 in the interior of the vacuum vessel 11 with respect to the region 60, and an independent space is secured. In this example, the processing in each of the areas 20, 40, and 60 is configured to be independently controllable.

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

  A sputtering gas supply unit 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). And). The sputtering gas is introduced into the region 20 (or 40) through piping, respectively. The mass flow controller 25 (or 45) is a device for adjusting 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 its flow rate adjusted by the mass flow controller 25 (or 45).

  The configuration of the plasma source 80 is also not particularly limited, but in the present example, a case body 81 fixed so as to close an opening formed in the wall surface of the vacuum vessel 11 from the outside, and a 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 accommodation chamber 82 is formed in a region surrounded by the case body 81 and the dielectric plate 83.

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

  Antennas 85 a and 85 b are installed in the antenna storage room 82. The antennas 85a and 85b are connected to an AC power supply 89 via a matching box 87 accommodating a matching circuit. The antennas 85 a and 85 b receive supply of power from the AC power supply 89 to generate an induction electric field in the inside of the vacuum vessel 11 (particularly, the area 60) and generate plasma in the area 60. In this example, an alternating current voltage is applied from the alternating current power supply 89 to the antennas 85a and 85b 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.

A 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 for storing reaction processing gas, and a mass flow controller 67 for adjusting the flow rate of the reaction processing gas supplied from the cylinder 68. The reaction processing gas is introduced into the region 60 through piping. The mass flow controller 67 is a device for adjusting the flow rate of the reaction processing gas. The flow rate of the reaction processing gas from the cylinder 68 is adjusted by the mass flow controller 67 and introduced into the region 60.
The reaction gas supply unit 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, inert gas and reactive gas). May be configured to include two gas cylinders that store 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 for film formation (a) First, 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, in addition to plastic substrates (organic glass substrates) and inorganic substrates (inorganic glass substrates), metal substrates such as stainless steel can be applied, and the thickness thereof is, for example, 0.1 to 5 mm. In addition, as an inorganic glass substrate which is an example of the board | substrate S, soda lime glass (6H-7H), borosilicate glass (6H-7H) etc. are mentioned, for example. In addition, the number in the parenthesis of an inorganic glass substrate is the value of the pencil hardness measured by the method based on JIS-K5600-5-4.
The arrangement of the substrates S is not particularly limited, but in the present example, a plurality of the substrates S are intermittently arranged along the rotational direction (lateral direction) of the substrate holder 13 on the outer peripheral surface of the substrate holder 13 A plurality of arrays are intermittently arranged along a parallel direction (longitudinal direction, Y direction, equal to the vertical direction of the vacuum vessel 11).

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

(B) Next, the inside of the vacuum vessel 11 is brought into 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 chamber of the plasma source 80 is simultaneously exhausted. Thereafter, the drive 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, and 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 areas 20 and 40 and the plasma exposure process performed in the area 60 are sequentially repeated to form a thin film having a predetermined film thickness on the surface of the substrate S.

  In the present embodiment, the rotational speed of the substrate holder 13 may be 10 rpm or more, preferably 50 rpm or more, and more preferably 80 rpm or more. By setting the rotational speed to 50 rpm or more, merits such as densification of film quality and shortening of processing time are increased, which is preferable. In the present 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 sputtering in one of the regions 20 and 40, and the intermediate thin film is converted into a super thin film in the subsequent plasma exposure treatment. Then, by repeating the sputtering process and the plasma exposure process, the next ultra thin film is deposited on the ultra thin film, and this operation is repeated until the final thin film is obtained.

  In the present example, the “intermediate thin film” refers to a thin film formed by passing through either the region 20 or the region 40. "Ultra thin film" is a term used to prevent confusion with this final "thin film" because the ultra thin film is deposited multiple times to become the final thin film (thin film of target thickness). It is used in the sense that it is sufficiently thinner than the final "thin film".

(2) Sputtering process 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 thereafter, a 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 a reactive gas such as nitrogen or oxygen is not used in combination. The introduction flow rate of the inert gas 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 to each of the electrodes 21a and 21b from the AC power supply 23 through 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). The “power density” means the power (W) supplied per unit area (cm ² ) of the target 29 a, 29 b (or 49 a, 49 b).

  By supplying power to the targets 29a and 29b, at a certain point of time, the target 29a becomes a cathode (minus electrode), and at this time, the target 29b always becomes an anode (plus electrode). 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). As a pair of targets 29a and 29b alternately become an anode and a cathode as described above, a part of sputtering gas (inert gas) around each target 29a and 29b emits electrons and is ionized. Leakage magnetic fields are formed on the surfaces of the targets 29a and 29b by the magnets disposed on the electrodes 21a and 21b, and these 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 trajectory of the electrons, and ions of the sputtering gas in this plasma are accelerated toward the negative potential state (cathode side) targets and collide with the respective targets 29a and 29b. As a result, the surfaces (target surfaces to be sputtered) of the targets 29a and 29b are sputtered, and atoms and particles (hereinafter collectively referred to as sputtered particles or target material) are emitted (sputtering treatment).

  During sputtering, non-conductive or poorly conductive incomplete reactants may be deposited on the anode, but when the anode is converted to a cathode by an alternating electric field, these may be deposited. Incomplete reaction substances and the like are sputtered to bring the target surface to its original clean state. Then, by repeating that the pair of targets 29a and 29b alternately become the anode and the cathode, a stable anode potential state is always obtained, and a change in plasma potential (usually equal to the anode potential) is prevented. The sputtered particles are stably emitted toward the surface of S.

  In this example, power (for example, 50 to 2000 W in the case of high frequency power, for example, 1000 V or less, preferably 30 to 1000 V in the case of direct current power) is supplied to each substrate electrode 18 during the sputtering process described above. And apply a voltage to each substrate S. By doing this, a potential is applied to the substrate electrode 18 with respect to the sputtering plasma, whereby a part of all ions of the sputtering gas present in the sputtering plasma is attracted to the substrate S side and collides with the substrate S surface. Energize 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. If this voltage is 5 V or more, merits such as densification of film quality and shortening of processing time can be easily obtained. The voltage here can be 1000 V or less. Here, the voltage means the output voltage when it is based on the power supplied from the DC power supply, and the self bias voltage (the negative voltage generated during the RF plasma discharge when it is based on the power supplied from the RF power supply). It means DC voltage).
It is desirable that the voltage applied to each substrate S be maintained at a predetermined value without changing during film formation.
The above is the sputtering process performed in the region 20 (film forming process by the bias sputtering method of 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, with the activation of the regions 20, 40, the activation of the region 60 is also initiated. Specifically, a reaction processing gas of a predetermined flow rate is introduced into the region 60 from the gas cylinder 68 through the mass flow controller 67, and the vicinity of the antennas 85a and 85b is made into a predetermined gas atmosphere.

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

  The power (plasma processing power) supplied from the AC power supply 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, it can be 1 kW or less.

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

  In this example, even 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. For this reason, as described above, the substrate electrode 18 is given an electric potential to the plasma other than the sputtering plasma, whereby ions of the reaction processing gas present in the plasma other than the sputtering plasma are on the substrate S side. It attracts and collides to give more energy to the intermediate thin film formed on the surface of the substrate S (plasma reprocessing).

  It is desirable that the voltage applied to each substrate S be maintained at a predetermined value from beginning to end, 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 as to slow up the applied voltage at 1000 V / sec or less at the timing of applying the voltage.

When the reactive processing gas to be introduced contains a reactive gas (for example, oxygen gas), active species of the reactive gas are present 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 subjected to plasma exposure treatment (oxidation treatment), and converted to a complete oxide of metal atoms to form an ultrathin film.
The above is 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 ultra thin 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). The final thin film having the desired film thickness is formed on all the substrates S held by the substrate holder 13.

  According to this embodiment, after film formation is performed by the conventional bias sputtering method in the film formation region 20 formed in a single vacuum container 11, the film formation region is spatially separated from the film formation region 20 and disposed Plasma reprocessing is performed in which ions in plasma other than the sputtering plasma in the film forming region 20 generated in the reaction region 60 collide with each other. That is, the thin film after bias sputtering is subjected to plasma treatment again. Thus, even if the voltage applied to the substrate S or the sputtering power in the region 20 is not increased, the effect of the plasma processing can be independently controlled by changing the processing conditions in the region 60.

(4) Other Embodiments The embodiments described above are described to facilitate the understanding of the invention, and are not described to limit the invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the above invention.

In the embodiment described above, after the final thin film of the target thickness is formed on the substrate S, the plasma post-processing may be further performed. Specifically, first, the rotation of the substrate holder 13 is temporarily stopped, and the operation in the regions 20 and 40 (supply of sputtering gas and power supply from the AC power supplies 23 and 43) is stopped. On the other hand, the operation of the area 60 is continued as it is. That is, in the region 60, the supply of the reaction processing gas and the supply of the power from the AC power supply 89 are continued to generate plasma continuously. In this state, when the substrate holder 13 is rerotated to transport the substrate S to the region 60, the thin film formed on the substrate S is plasma-treated while passing through the region 60 (post-processing). By applying the plasma post-treatment, an effect such as improvement of the surface flatness of the final thin film can be expected.
When the plasma post-treatment is performed, the plasma exposure treatment at the time of forming the thin film and the plasma post-treatment after the thin film formation may be performed under the same conditions or may be performed under different conditions. When the plasma post-treatment is performed, for example, the concentration of the reactive gas in the mixed gas may be varied. In addition, in the case where the plasma post-processing is performed, the plasma processing power (power supplied from the AC power supply 89) may be varied with respect to the plasma exposure process in forming the thin film. In this case, it can be adjusted by the matching box 87. The time for plasma post-treatment is, for example, in the range of about 1 to 60 minutes and an appropriate time.

  Although the case where a thin film is formed into a film using the film-forming apparatus 1 by the magnetron sputtering which is an example of sputtering was illustrated in embodiment mentioned above, it is not limited to this, 2 pole sputtering etc. which do not use magnetron discharge, etc. It is also possible to form a film by another sputtering method using a film formation apparatus for performing the known sputtering. However, the atmosphere at the time of sputtering is an inert gas atmosphere in each case.

  Next, the invention will be described in more detail by way of specific examples of the above-described embodiment of the invention.

[Experimental Example 1]
100 substrates S are set to the substrate holder 13 using the film forming apparatus 1 shown in FIG. 1 and FIG. 2, and sputtering in the region 20 and plasma exposure in the region 60 are repeated under the following conditions. Several experimental example samples in which the 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)
Deposition rate: 0.1 nm / s,
Substrate temperature: room temperature.

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

<Plasma exposure in area 60>
・ Reaction treatment gas: Ar,
・ Gas pressure for reaction processing: 0.11 Pa,
· Introduction flow rate of reaction processing gas: 60 sccm,
Electric power supplied from the AC power supply 89 to the antennas 85a and 85b (plasma processing electric power): 0 W, 400 W, 500 W, 600 W, 800 W, 1000 W, 1000 W, 2500 W, 5000 W.-Frequency of AC voltage applied to the antennas 85 a, 85 b: 13 .56 MHz.

<Film hardness>
Using a microhardness tester (MMT-X7, manufactured by Matsuzawa Co., Ltd.), the hardness (GPa) of the DLC thin film surface of the sample of the experimental example was measured under the following measurement conditions.
· Indenter shape: Vickers indenter (a = 136 °),
・ Measurement environment: Temperature 20 ° C, 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 sample changed depending on the plasma processing power in the region 60. Thus, the film hardness of the obtained thin film is adjusted by changing the conditions of only the plasma processing power in the region 60 while keeping the sputtering power density in the region 20 and the substrate bias supply power in the region 20 and the region 60 constant. It can be understood that (control) can do.

[Experimental Example 2]
36 substrates S are set on the substrate holder 13 using the film forming apparatus 1 shown in FIG. 1 and FIG. 2, and sputtering in the region 20 and plasma exposure in the region 60 are repeated under the following conditions. Several experimental example samples in which the SiO ₂ thin film was formed on the 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)
Deposition rate: 0.1 nm / s,
Substrate temperature: room temperature.

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

<Plasma exposure in area 60>
· Reaction processing gas: O ₂ ,
· O ₂ concentration in reaction processing gas: 100%,
・ Reaction processing gas pressure: 0.1 Pa,
Introduction flow rate of reaction processing gas: 50 sccm,
Electric power (plasma processing electric power) supplied from the AC power supply 89 to the antennas 85a and 85b: 2 kW, 3 kW, 4 kW, 4.5 kW,
-Frequency of AC voltage applied to the antennas 85a and 85b: 13.56 MHz.

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

  In the regions 20 and 60, ions in the sputtering plasma and ions in the plasma other than the sputtering plasma are both attracted to the respective substrates S by the voltage applied to the respective substrates S and collide with the thin film. A film which can not be formed into 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 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 constant, and the conditions of only the plasma processing power in the region 60 are changed to adjust the etching rate of the obtained thin film It can be understood that (control) can do.

  As a result, in the step coverage (the covered state at the fine step portion), it becomes possible to control the film forming rate of the side portion and the bottom portion at the step portion, and for example, as shown in FIG. obtain.

Claims (6)

A vacuum chamber having an exhaust system,
A deposition region formed in a 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 sputtering discharge in a film formation area facing the target sputtering surface;
Plasma generating means for generating plasma other than sputtering plasma by sputtering discharge generated in the film formation region in the reaction region;
A cylindrical substrate holder having a plurality of substrate holding parts on its outer peripheral surface;
Drive means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region to which 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 whose back surface is held by the substrate holder is repeatedly moved between
A plurality of substrate electrodes which are not electrically connected to the substrate holder and provided at the back surface position of each substrate holder;
Further comprising a bias power supply for supplying power to each of the substrate electrode,
The distance to the inner circumferential surface of the substrate holder is adjusted in the range of 0.10 to 0.14 mm for each substrate electrode,
The film-forming apparatus using what was comprised so that connection to one or both of DC power supply and high frequency power supply was possible as said bias power supply. A vacuum chamber having an exhaust system,
A deposition region formed in a 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 sputtering discharge in a film formation area facing the target sputtering surface;
Plasma generating means for generating plasma other than sputtering plasma by sputtering discharge generated in the film formation region in the reaction region;
A cylindrical substrate holder having a plurality of substrate holding parts on its outer peripheral surface;
Drive means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region to which 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 whose back surface is held by the substrate holder is repeatedly moved between
A plurality of substrate electrodes which are not electrically connected to the substrate holder and provided at the back surface position of each substrate holder;
Further comprising a bias power supply for supplying power to each of the substrate electrode,
Each substrate electrode is formed to have a size of 80 to 98% of the size of the substrate held by each substrate holding portion, and the inner circumferential surface of the substrate holder corresponding to the back surface position of each substrate holding portion is insulated Yes,
The film-forming apparatus using what was comprised so that connection to one or both of DC power supply and high frequency power supply was possible as said bias power supply. A vacuum chamber having an exhaust system,
A deposition region formed in a 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 sputtering discharge in a film formation area facing the target sputtering surface;
Plasma generating means for generating plasma other than sputtering plasma by sputtering discharge generated in the film formation region in the reaction region;
A cylindrical substrate holder having a plurality of substrate holding parts on its outer peripheral surface;
Drive means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region to which 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 whose back surface is held by the substrate holder is repeatedly moved between
A plurality of substrate electrodes which are not electrically connected to the substrate holder and provided at the back positions of the respective substrate holders;
And a bias power supply for supplying power to each of the substrate electrodes,
The distance to the inner circumferential surface of the substrate holder is adjusted in the range of 0.10 to 0.14 mm for each substrate electrode,
As the bias power supply, one configured to be connectable to one or both of a DC power supply and a high frequency power supply is used,
The target is mounted on the cathode electrode, the sputtering power is turned on, and the plasma generation means is operated, and a plurality of substrates are held on the outer peripheral surface of the substrate holder, and power is supplied to the substrate electrodes to apply voltage to the substrates. By rotating the holder, the sputtered particles emitted from the target reach and deposit on the substrate moved to the deposition region, and at the same time, the plasma in which the ions in the sputtering plasma collide with the substrate or the deposited sputtered particles After processing to form an intermediate thin film, the intermediate thin film of the substrate that has moved to the reaction area is subjected to plasma reprocessing in which ions in the plasma different from sputtering plasma are collided to perform film conversion into an ultra thin film. A film forming apparatus configured to form a thin film by laminating a plurality of the ultra thin films. A vacuum chamber having an exhaust system,
A deposition region formed in a 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 sputtering discharge in a film formation area facing the target sputtering surface;
Plasma generating means for generating plasma other than sputtering plasma by sputtering discharge generated in the film formation region in the reaction region;
A cylindrical substrate holder having a plurality of substrate holding parts on its outer peripheral surface;
Drive means for rotating the substrate holder,
By rotating the substrate holder by the driving means, a predetermined position in the film formation region to which 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 whose back surface is held by the substrate holder is repeatedly moved between
A plurality of substrate electrodes which are not electrically connected to the substrate holder and provided at the back positions of the respective substrate holders;
And a bias power supply for supplying power to each of the substrate electrodes,
Each substrate electrode is formed to have a size of 80 to 98% of the size of the substrate held by each substrate holding portion, and the inner circumferential surface of the substrate holder corresponding to the back surface position of each substrate holding portion is insulated Yes,
As the bias power supply, one configured to be connectable to one or both of a DC power supply and a high frequency power supply is used,
The target is mounted on the cathode electrode, the sputtering power is turned on, and the plasma generation means is operated, and a plurality of substrates are held on the outer peripheral surface of the substrate holder, and power is supplied to the substrate electrodes to apply voltage to the substrates. By rotating the holder, the sputtered particles emitted from the target reach and deposit on the substrate moved to the deposition region, and at the same time, the plasma in which the ions in the sputtering plasma collide with the substrate or the deposited sputtered particles After processing to form an intermediate thin film, the intermediate thin film of the substrate that has moved to the reaction area is subjected to plasma reprocessing in which ions in the plasma different from sputtering plasma are collided to perform film conversion into an ultra thin film. A film forming apparatus configured to form a thin film by laminating a plurality of the ultra thin films. Each substrate electrode is 80 to 98% of is formed in a size according to claim 1 or 3 film forming apparatus according to the size of the substrate held in the respective substrate holder. The film forming apparatus according to claim 5 , wherein an inner circumferential surface of the substrate holder corresponding to the back surface position of each substrate holding unit is insulated.

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