Film formation apparatus and film formation method using magnetron sputtering

Abstract

In a film formation apparatus and a film formation method using magnetron sputtering, high reproducibility is achieved even when a reactive film is formed by simultaneously introducing a plurality of types of reactive gases into a vacuum chamber. [Solution] In a magnetron sputtering apparatus (10) according to the present invention, the flow rate Qd of an inert gas introduced into a vacuum chamber (12) is kept constant, and the angle θ of a conductance valve (22) is kept constant, i.e., the effective pumping speed at an exhaust port (14) of the vacuum chamber (12) is kept constant. Additionally, the sputtering power Es, the arc discharge power Ed, and the substrate bias voltage Vb are kept constant. Furthermore, a gas flow rate ratio Rq, which is the ratio between the flow rates Qr1 and Qr2 of the reactive gases introduced into the vacuum chamber (12), is kept constant, and a total gas flow rate Qa, which is the sum of the flow rates Qr1 and Qr2 of the reactive gases, is controlled so that the pressure P inside the vacuum chamber (12) is kept constant.

Description

[Technical Field]

[0001] The present invention relates to a film formation apparatus and a film formation method using magnetron sputtering, and more particularly to a film formation apparatus and a film formation method using so-called reactive magnetron sputtering, which forms a reactive film on a workpiece. [Background technology]

[0002] One example of this type of technology is disclosed in Patent Document 1. According to the technology disclosed in Patent Document 1, a magnetron sputtering cathode having a target serving as a reactive film material is provided inside a vacuum chamber at ground potential. A workpiece (substrate) is also provided inside the vacuum chamber, facing the sputtering surface of the target. Furthermore, an earth shield is provided surrounding the magnetron sputtering cathode, with the sputtering surface of the target (only) exposed. This earth shield is also at ground potential. The vacuum chamber is evacuated by a vacuum pump constituting an exhaust means, and the effective exhaust speed at the exhaust port of the vacuum chamber is controlled by a conductance valve constituting the exhaust means. Additionally, an inert gas is introduced (supplied) into the vacuum chamber at a constant flow rate. In this state, the earth shield serves as the anode, i.e., the vacuum chamber serves as the anode, and the magnetron sputtering cathode serves as the cathode, and sputtering power is supplied to both. This causes particles of the inert gas to discharge, inducing (generating) magnetron plasma so that they stick to the sputtering surface of the target. The discharge mode of this magnetron plasma is a high-voltage, low-current glow discharge, and the magnetron plasma contains a mixture of ions, electrons, and neutral particles (including radicals). The magnetron plasma sticks to the sputtering surface of the target due to the action of a magnetic field generated by a magnet that serves as a magnetic field generating means provided in the magnetron sputtering cathode.

[0003] Particles of the inert gas in the magnetron plasma, specifically ions, collide with the sputtering surface of the target, knocking target particles off the sputtering surface, i.e., sputtering. The sputtering region, or the area to be sputtered, is limited to the sputtering surface of the target, specifically, the aforementioned earth shield is provided to ensure this. A reactive gas, which will form the reactive film, is then introduced into the vacuum chamber. The particles of this reactive gas are decomposed by the magnetron plasma, and some of them are ionized. Furthermore, the sputtered particles sputtered from the sputtering surface of the target, or more specifically, some of the sputtered particles, are also ionized by the magnetron plasma. A constant bias power with a predetermined component is supplied to both the vacuum chamber as the anode and the workpiece as the cathode. This accelerates the inert gas particles, reactive gas particles, and sputtered particles—specifically, the ions of these particles, or more specifically, the ions present near the surface (sheath) of the workpiece—toward the workpiece. In particular, reactive gas particles and sputtered particles adhere to the surface of the workpiece (the surface to be processed) and react with each other, forming a reaction film, which is a compound film composed of the reactive gas particles and sputtered particles, on the surface of the workpiece. The particles that form this reaction film contain ions, and the bonding force between the ions contributes to the densification of the reaction film. Additionally, the bombardment effect caused by the collision of inert gas ions with the surface of the workpiece contributes to the improvement of the density of the reaction film. The predetermined component of the bias power is, for example, the average or effective value of the bias voltage, which is the voltage component of the bias power.

[0004] Additionally, a cathode filament is provided inside the vacuum chamber between the target surface to be sputtered and the workpiece. Heating power is supplied to the cathode filament, causing it to heat and emit thermoelectrons. Furthermore, arc discharge power is supplied to the earth shield, which serves as the anode, and the cathode filament, which serves as the cathode. The thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, where they collide with inert gas particles, reactive gas particles, and sputter particles. Because the aforementioned magnetic field is formed around the cathode filament, the thermoelectrons accelerated from the cathode filament toward the earth shield undergo spiral motion (cycloidal motion or trochoidal motion) due to the effect of the magnetic field. This increases the frequency with which the thermoelectrons collide with inert gas particles, reactive gas particles, and sputter particles, inducing a low-voltage, high-current arc discharge around the cathode filament. In other words, in addition to the magnetron plasma generated by the glow discharge, an extremely high-density plasma generated by the arc discharge is induced around the cathode filament, i.e., between the sputtering surface of the target and the workpiece. Similar to the magnetron plasma, this arc discharge plasma also contains a mixture of ions, electrons, and neutral particles.

[0005] Therefore, sputtered particles sputtered from the sputtering surface of the target pass through a space of extremely high-density plasma on their way toward the workpiece. As a result, the sputtered particles are activated, have energy at least higher than that of the ground state, and are ionized particularly efficiently. Similarly, particles of the reactive gas are also activated and ionized efficiently. At the same time, particles of the inert gas are also activated and ionized efficiently. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece, and further densifies the reaction film formed on the surface of the workpiece.

[0006] Furthermore, while the voltage component of the arc discharge power, i.e., the arc discharge voltage, is kept constant, the heating power is controlled so that the current component of the arc discharge power, i.e., the arc discharge current, is kept constant; in other words, the amount of thermoelectrons emitted from the cathode filament is controlled. That is, the amount of thermoelectrons emitted by the cathode filament is automatically controlled (feedback controlled) so that the arc discharge current is kept constant, using the arc discharge current as a parameter. This stabilizes the density of the plasma generated by the arc discharge.

[0007] Furthermore, while the sputtering power is kept constant and the effective pumping speed at the exhaust port of the vacuum chamber by the vacuum pump is kept constant by the conductance valve, the flow rate of the reactive gas into the vacuum chamber is controlled to maintain a constant pressure inside the vacuum chamber. That is, the flow rate of the reactive gas into the vacuum chamber is automatically controlled to maintain a constant pressure inside the vacuum chamber using the pressure inside the vacuum chamber as a parameter. This maintains a constant sputtering rate (the amount (number) of sputtered particles per unit time and unit area; it is sometimes called the "sputter evaporation rate," but because it cannot be measured directly, it is typically expressed as the mass of particles sputtered per unit time (g / min)). This maintains a constant balance between the amount of sputtered particles and the amount of reactive gas particles, thereby improving the reproducibility of the target reactive film. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 7445071 Summary of the Invention [Problem to be solved by the invention]

[0009] Incidentally, Patent Document 1 cites a titanium nitride (TiN) film as a specific example of a reactive film. When forming this titanium nitride film, a titanium (Ti) target is used, and nitrogen (N2) gas is used as the reactive gas. It is claimed that the technology disclosed in Patent Document 1 makes it possible to form a titanium nitride film, particularly a titanium nitride film with a golden hue that conforms to the stoichiometric composition, with high reproducibility (see paragraphs

[0054] -

[0098] of Patent Document 1).

[0010] Furthermore, the technology disclosed in Patent Document 1 is said to be applicable to the formation of various reactive films other than titanium nitride films, such as titanium carbonitride (TiCN) films (see paragraph

[0103] of Patent Document 1). For example, when forming a titanium carbonitride film, a titanium target is used, and a hydrocarbon gas such as acetylene (C2H2) gas is used as the reactive gas in addition to nitrogen gas; in other words, multiple types of reactive gases are used. These multiple types of reactive gases are introduced simultaneously (in parallel) into a vacuum chamber.

[0011] However, Patent Document 1 does not disclose at all how to form a reactive film, particularly how to control the flow rate of each reactive gas, when a reactive film is formed by simultaneously introducing multiple types of reactive gases into a vacuum chamber, including when a titanium carbonitride film is formed. In other words, Patent Document 1 suggests the possibility of applying the technology disclosed in Patent Document 1 to a case where a reactive film is formed by simultaneously introducing multiple types of reactive gases into a vacuum chamber, but does not disclose any specific procedures for such a case.

[0012] Therefore, an object of the present invention is to provide a film formation apparatus and a film formation method using a novel reactive magnetron sputtering method that can form a reactive film with high reproducibility even when multiple types of reactive gases are introduced into a vacuum chamber simultaneously to form the reactive film. [Means for solving the problem]

[0013] To achieve this object, the present invention includes a first invention relating to a film formation apparatus using a reactive magnetron sputtering method, and a second invention relating to a film formation method using the reactive magnetron sputtering method.

[0014] Among these, a first invention relating to a film formation apparatus using a reactive magnetron sputtering method includes a vacuum chamber, a magnetron sputtering cathode, an earth shield, an exhaust means, an inert gas introduction means, a sputtering power supply means, a reactive gas introduction means, a bias power supply means, a cathode filament, a heating power supply means, an arc discharge power supply means, a heating power control means, and a reactive gas flow rate control means. Specifically, the vacuum chamber is grounded, i.e., at ground potential, and a workpiece is accommodated within the vacuum chamber. The magnetron sputtering cathode has a target that will be the material for the reactive film, and is installed within the vacuum chamber so that the sputtering surface of the target faces the workpiece. The earth shield is installed to surround the outer periphery of the magnetron sputtering cathode, leaving only the sputtering region of the target exposed. The earth shield is also grounded, i.e., at ground potential. The exhaust means includes a vacuum pump and a conductance valve. A vacuum pump evacuates the interior of the vacuum chamber through the exhaust port of the vacuum chamber. A conductance valve controls the effective pumping speed at the exhaust port of the vacuum chamber. An inert gas introducing means introduces an inert gas as a discharge gas into the vacuum chamber at a constant flow rate. A sputtering power supply means supplies sputtering power to the earth shield, i.e., the vacuum chamber, as the anode, and the magnetron sputtering cathode, as the cathode. This causes discharge of inert gas particles, inducing magnetron plasma so that the particles adhere to the sputtering surface of the target. The magnetron plasma discharges in the form of a high-voltage, low-current glow discharge, and the magnetron plasma contains a mixture of ions, electrons, and neutral particles. The magnetron plasma adheres to the sputtering surface of the target due to the action of a magnetic field generated by a magnetic field generating means provided in the magnetron sputtering cathode.

[0015] Particles of the inert gas in the magnetron plasma, specifically ions, collide with the sputtering surface of the target, knocking particles constituting the target from the sputtering surface, i.e., sputtering. The sputtering area, which is the area to be sputtered, is limited to the sputtering surface of the target, i.e., the aforementioned earth shield is provided to ensure this. Furthermore, the reactive gas introducing means simultaneously introduces multiple reactive gases, which are materials for the reactive film, into the vacuum chamber. Particles of each reactive gas are decomposed by the magnetron plasma, and some of them are ionized. Furthermore, sputtered particles sputtered from the sputtering surface of the target, or more precisely, some of the sputtered particles, are also ionized by the magnetron plasma. The bias power supplying means supplies a constant bias power with a predetermined composition to both the vacuum chamber as the anode and the workpiece as the cathode. This accelerates the inert gas particles, the reactive gas particles, and the sputtered particles—specifically, the ions among these particles, more specifically, the ions present near the surface of the workpiece—toward the workpiece. In particular, particles of each reactive gas and sputtered particles adhere to the surface of the workpiece and react with each other, forming a reaction film composed of the particles of each reactive gas and the sputtered particles on the surface of the workpiece. The particles that form this reaction film contain ions, and the bonding force between the ions contributes to the densification of the reaction film. Additionally, the bombardment effect caused by the collision of ions of the inert gas with the surface of the workpiece contributes to the improvement of the density of the reaction film. The predetermined component of the bias power is, for example, the average or effective value of the bias voltage, which is the voltage component of the bias power.

[0016] Additionally, a cathode filament is provided inside the vacuum chamber between the sputtering surface of the target and the workpiece. The heating power supply supplies heating power to the cathode filament, causing it to heat and emit thermoelectrons. The arc discharge power supply supplies arc discharge power to the earth shield, which serves as the anode, and the cathode filament, which serves as the cathode. The thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, where they collide with inert gas particles, reactive gas particles, and sputter particles. Because the aforementioned magnetic field is formed around the cathode filament, the thermoelectrons accelerated from the cathode filament toward the earth shield spiral due to the effect of the magnetic field. This increases the frequency with which the thermoelectrons collide with inert gas particles, reactive gas particles, and sputter particles, inducing a low-voltage, high-current arc discharge around the cathode filament. In other words, in addition to the magnetron plasma generated by the glow discharge, an extremely high-density plasma generated by the arc discharge is induced around the cathode filament, i.e., between the sputtering surface of the target and the workpiece. Similar to the magnetron plasma, this arc discharge plasma also contains a mixture of ions, electrons, and neutral particles.

[0017] Therefore, sputtered particles sputtered from the sputtering surface of the target pass through a space of extremely high-density plasma on their way toward the workpiece. This activates the sputtered particles and efficiently ionizes them. Similarly, particles of each reactive gas are also activated and efficiently ionized. At the same time, particles of the inert gas are also activated and efficiently ionized. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece, and further densifies the reaction film formed on the surface of the workpiece.

[0018] The heating power control means controls the heating power so that the current component of the arc discharge power, that is, the arc discharge current, is constant while the voltage component of the arc discharge power, that is, the arc discharge voltage, is kept constant; in other words, it controls the amount of thermoelectrons emitted from the cathode filament. That is, the amount of thermoelectrons emitted by the cathode filament is automatically controlled using the arc discharge current as a parameter so that the arc discharge current is kept constant. This stabilizes the density of the plasma generated by the arc discharge.

[0019] Furthermore, the reactive gas flow rate control means controls the total flow rate, which is the sum of the flow rates of each reactive gas into the vacuum chamber, while maintaining the relative ratio of the flow rates of each reactive gas constant so that the pressure inside the vacuum chamber is constant. In other words, it controls the flow rates of each reactive gas individually so that this happens, for example, by controlling the reactive gas introduction means. That is, using the pressure inside the vacuum chamber as a parameter, it controls the total flow rate, which is the sum of the flow rates of each reactive gas into the vacuum chamber, while maintaining the relative ratio of the flow rates of each reactive gas into the vacuum chamber constant so that the pressure inside the vacuum chamber is constant. In other words, it automatically controls the flow rates of each reactive gas individually so that this happens. At this time, the sputtering power is kept constant, and the effective pumping speed at the exhaust port of the vacuum chamber by the vacuum pump is kept constant by the conductance valve. This keeps the sputtering rate constant, maintains a constant balance between the amount of particles of each reactive gas relative to the amount of sputtered particles, and also maintains a constant balance between the amount of particles of each reactive gas (between each other).

[0020] The ratio of the flow rates of the reactive gases into the vacuum chamber may be set arbitrarily, and the reactive gas flow rate control means may be configured to set this ratio.

[0021] A second aspect of the present invention, which relates to a film formation method using reactive magnetron sputtering, includes a workpiece placement step, an evacuation step, an inert gas introduction step, a sputtering power supply step, a reactive gas introduction step, a bias power supply step, a heating power supply step, an arc discharge power supply step, a heating power control step, and a reactive gas flow rate control step. In the workpiece placement step, the workpiece is placed inside a vacuum chamber equipped with a magnetron sputtering cathode having a target serving as a reactive film material, facing the sputtering surface of the target. The vacuum chamber is grounded, i.e., at ground potential. An earth shield is installed around the magnetron sputtering cathode, with only the sputtering surface of the target exposed. This earth shield is also grounded, i.e., at ground potential. In the evacuation step, the interior of the vacuum chamber is evacuated by a vacuum pump through an exhaust port of the vacuum chamber. The effective pumping speed at the exhaust port of the vacuum chamber is controlled by a conductance valve. In the inert gas introduction step, an inert gas is introduced into the vacuum chamber at a constant flow rate as a discharge gas. In the sputtering power supply step, sputtering power is supplied to both the earth shield (i.e., the vacuum chamber) as the anode and the magnetron sputtering cathode as the cathode. This causes discharge of inert gas particles, inducing magnetron plasma so that the particles adhere to the sputtering surface of the target. The magnetron plasma discharge mode is a high-voltage, low-current glow discharge, and the magnetron plasma contains a mixture of ions, electrons, and neutral particles. The magnetron plasma adheres to the sputtering surface of the target due to the action of a magnetic field generated by a magnetic field generating means provided in the magnetron sputtering cathode.

[0022] Particles of the inert gas in the magnetron plasma, specifically ions, collide with the sputtering surface of the target, knocking out particles constituting the target from the sputtering surface, i.e., sputtering. The sputtering region, which is the area to be sputtered, is limited to the sputtering surface of the target, i.e., the aforementioned earth shield is provided to ensure this. Furthermore, in the reactive gas introduction step, multiple reactive gases serving as materials for the reactive film are simultaneously introduced into the vacuum chamber. Particles of each reactive gas are decomposed by the magnetron plasma, and some of them are ionized. Furthermore, sputtered particles sputtered from the sputtering surface of the target, or more precisely, some of the sputtered particles, are also ionized by the magnetron plasma. Then, in the bias power supply step, a constant bias power with a predetermined component is supplied to the vacuum chamber as the anode and the workpiece as the cathode. This accelerates the inert gas particles, reactive gas particles, and sputtered particles sputtered from the sputtering surface of the target toward the workpiece. In particular, particles of each reactive gas and sputtered particles adhere to the surface of the workpiece and react with each other, forming a reaction film composed of the particles of each reactive gas and the sputtered particles on the surface of the workpiece. The particles that form this reaction film contain ions, and the bonding force between the ions contributes to the densification of the reaction film. Additionally, the bombardment effect caused by the collision of ions of the inert gas with the surface of the workpiece contributes to the improvement of the density of the reaction film. The predetermined component of the bias power is, for example, the average or effective value of the bias voltage, which is the voltage component of the bias power.

[0023] In the heating power supply step, heating power is supplied to the cathode filament. The cathode filament is disposed inside the vacuum chamber between the sputtering surface of the target and the workpiece. The cathode filament is heated by the heating power and emits thermoelectrons. In the arc discharge power supply step, arc discharge power is supplied to the earth shield as the anode and the cathode filament as the cathode. The thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, and collide with particles of the inert gas, particles of each reactive gas, and sputter particles. Because the magnetic field described above is formed around the cathode filament, the thermoelectrons accelerated from the cathode filament toward the earth shield move in a spiral motion due to the effect of the magnetic field. This increases the frequency with which the thermoelectrons collide with particles of the inert gas, particles of each reactive gas, and sputter particles, inducing a low-voltage, high-current arc discharge around the filament. In other words, in addition to the magnetron plasma generated by the glow discharge, an extremely high-density plasma generated by the arc discharge is induced around the cathode filament, i.e., between the sputtering surface of the target and the workpiece. Similar to the magnetron plasma, this arc discharge plasma also contains a mixture of ions, electrons, and neutral particles.

[0024] Therefore, sputtered particles sputtered from the sputtering surface of the target pass through a space of extremely high-density plasma on their way toward the workpiece. This activates the sputtered particles and efficiently ionizes them. Similarly, particles of each reactive gas are also activated and efficiently ionized. At the same time, particles of the inert gas are also activated and efficiently ionized. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece, and further densifies the reaction film formed on the surface of the workpiece.

[0025] Then, in the heating power control step, the heating power is controlled so that the current component of the arc discharge power, i.e., the arc discharge current, is kept constant while the voltage component of the arc discharge power, i.e., the arc discharge voltage, is kept constant; in other words, the amount of thermoelectrons emitted from the cathode filament is controlled. That is, the amount of thermoelectrons emitted by the cathode filament is automatically controlled using the arc discharge current as a parameter so that the arc discharge current is kept constant. This stabilizes the density of the plasma generated by the arc discharge.

[0026] Furthermore, in the reactive gas flow rate control step, the ratio of the flow rates of the reactive gases into the vacuum chamber is kept constant, while the total flow rate, which is the sum of the flow rates of the reactive gases, is controlled, i.e., the flow rates of the reactive gases are individually controlled so that the pressure inside the vacuum chamber is constant. That is, using the pressure inside the vacuum chamber as a parameter, the ratio of the flow rates of the reactive gases into the vacuum chamber is kept constant, while the total flow rate, which is the sum of the flow rates of the reactive gases, is controlled, i.e., the flow rates of the reactive gases are individually automatically controlled so that the pressure inside the vacuum chamber is constant. At this time, the sputtering power is kept constant, and the effective pumping speed at the exhaust port of the vacuum chamber by the vacuum pump is kept constant by the conductance valve. This keeps the sputtering rate constant, the balance of the amount of particles of each reactive gas relative to the amount of sputtered particles, and the balance of the amount of particles between the particles of each reactive gas (between each other) is kept constant. [Effects of the Invention]

[0027] According to the present invention, even when a reaction film is formed by simultaneously introducing a plurality of types of reactive gases into a vacuum chamber, the reaction film can be formed with high reproducibility. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a magnetron sputtering apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a top view of the inside of a magnetron sputtering apparatus according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a schematic configuration of a magnetron sputtering cathode in one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relative positions of a magnetron sputtering cathode and a cathode filament in one embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing experimental results in one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing another experimental result in an embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing still another experimental result in an embodiment of the present invention. [Figure 8] FIG. 8 is another diagram showing the experimental results according to FIG. [Figure 9] FIG. 9 is a diagram showing still another experimental result in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] An embodiment of the present invention will be described with reference to FIGS.

[0030] As shown in FIGS. 1 and 2 , a magnetron sputtering apparatus 10 according to this embodiment includes a generally cylindrical vacuum chamber 12 with both ends closed. The vacuum chamber 12 is installed with both ends of the generally cylindrical shape facing up and down, i.e., with the central axis Xa of the generally cylindrical shape extending vertically. The inner diameter of the vacuum chamber 12 is, for example, approximately 1100 mm, and the height within the vacuum chamber 12 is, for example, approximately 800 mm. The shape and dimensions of the vacuum chamber 12 are merely examples and are determined appropriately depending on various factors, such as the size, shape, and number of workpieces 100 (described below). The vacuum chamber 12 itself is made of a highly corrosion-resistant and heat-resistant metal, such as stainless steel such as SUS304, and its wall is grounded, i.e., serves as a reference potential.

[0031] An exhaust port 14 is provided at an appropriate position on the wall of the vacuum chamber 12, for example, at an appropriate position on the wall forming the side surface. The exhaust port 14 is connected to a vacuum pump 18 via an exhaust pipe 16 outside the vacuum chamber 12, and more precisely, is connected to an intake port (not shown) of the vacuum pump 18. The vacuum pump 18 may be, for example, a turbomolecular pump, but is not limited to this. In addition, in FIG. 2, for ease of viewing, some elements such as the exhaust port 14, the exhaust pipe 16, and the vacuum pump 18 are not shown.

[0032] A main valve, i.e., an on-off valve 20, is provided midway along the exhaust pipe 16 as an on-off means for opening and closing the inside of the exhaust pipe 16. Also provided midway along the exhaust pipe 16 is a conductance valve 22 for controlling the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 by the vacuum pump 18. The vacuum pump 18 and the conductance valve 22 constitute an exhaust means. Although not shown in detail, the conductance valve 22 has a plurality of elongated, plate-like blade members arranged parallel to each other like blinds, and the angle θ of these blade members controls the effective pumping speed at the exhaust port 14 of the vacuum chamber 12. For example, the smaller the angle θ of the conductance valve 22 (blade member), the greater the conductance, and when the angle θ is 0 degrees, the conductance valve is fully open. Conversely, the larger the angle θ of the conductance valve 22, the smaller the conductance, and when the angle θ is 90 degrees, the conductance valve 22 is fully closed. This configuration of the conductance valve 22 is an example, and the configuration of the conductance valve 22 is not limited to this.

[0033] Furthermore, a magnetron sputtering cathode 24 is provided at an appropriate position (on the right side in FIGS. 1 and 2) inside a wall forming a side surface of vacuum chamber 12, while being electrically insulated from the wall of vacuum chamber 12. Referring also to FIG. 3, magnetron sputtering cathode 24 has a target 242 having a generally rectangular flat plate shape that serves as a coating material, and a magnet unit 244 provided on the back side, which is one main surface, of target 242. Magnet unit 244 has a permanent magnet 246 as an example of magnetic field generating means, and a housing 248 that houses permanent magnet 246. Furthermore, the permanent magnet 246 has one magnetic pole, for example, an N-pole 246a, in a roughly rectangular frame shape, which is provided along the periphery of the target 242 while being in close contact with the back surface of the target 242, and the other magnetic pole, for example, an S-pole 246b, in a long, slender protrusion shape, which is provided inside the N-pole 246a, in close contact with the back surface of the target 242 and extends along the longitudinal direction of the target 242. The dimensions of the target 242 are, for example, 457 mm in the longitudinal direction (length), 127 mm in the lateral direction (width), and 8 mm in the thickness direction (thickness). A roughly rectangular groove-shaped gap 246c is provided between the N-pole 246a and the S-pole 246b of the permanent magnet 246. The housing 248 is provided with an appropriate water-cooling mechanism (not shown) as cooling means for cooling the entire magnetron sputtering cathode 24, including the housing 248.

[0034] The magnetron sputtering cathode 24 is disposed such that the sputtering surface, which is the other main surface (front surface) of the target 242, faces the central axis Xa of the vacuum chamber 12, and the longitudinal direction of the target 242 extends along the central axis Xa of the vacuum chamber 12, i.e., vertically. The magnetron sputtering cathode 24 is covered by an earth shield 26, except for the sputtering surface of the target 242. In other words, the earth shield 26 is disposed to surround the outer periphery of the magnetron sputtering cathode 24, leaving (only) the sputtering surface of the target 242 of the magnetron sputtering cathode 24 exposed. The earth shield 26 is made of a metal with high corrosion resistance and heat resistance, such as stainless steel such as SUS304. The earth shield 26 is electrically insulated from the magnetron sputtering cathode 24 and electrically connected to the wall of the vacuum chamber 12, i.e., is at ground potential.

[0035] More specifically, as described above, the earth shield 26 is provided to surround the outer periphery of the magnetron sputtering cathode 24, with the sputtering surface of the target 242 of the magnetron sputtering cathode 24 exposed. However, the distance between the outer surface of the magnetron sputtering cathode 24 and the inner surface of the earth shield 26 is quite small, e.g., about 2 mm. The earth shield 26 is substantially flush with the sputtering surface of the target 242 and has a protruding portion that protrudes away from the sputtering surface (i.e., along the extension direction of the central axis Xa of the vacuum chamber 12), with the protruding dimension of this protruding portion being, e.g., 20 mm to 30 mm. The earth shield 26 is electrically and mechanically coupled to the wall of the vacuum chamber 12, but is also directly grounded (separately from the vacuum chamber 12) as shown in FIG. 1 to more reliably maintain its own potential at ground potential.

[0036] 2, the portion 12a of the wall of the vacuum chamber 12 where the magnetron sputtering cathode 24 and the earth shield 26 are provided has a structure suitable for providing the magnetron sputtering cathode 24 and the earth shield 26. Taking into consideration the ease of operation during maintenance of the magnetron sputtering cathode 24, including replacement of the target 242, this portion 12a is preferably made openable and closable like a sliding door or a hinged door.

[0037] 1, the magnetron sputtering cathode 24 is connected to a DC sputtering power supply 28, which is an example of a sputtering power supply means, outside the vacuum chamber 12. Sputtering power Es, which is DC power with a negative potential relative to the ground potential, is supplied to the magnetron sputtering cathode 24 from the sputtering power supply 28. In other words, the vacuum chamber 12 serves as the anode, and strictly speaking the earth shield 26 serves as the anode and the magnetron sputtering cathode 24 serves as the cathode, and sputtering power Es is supplied to both of them. The sputtering power supply 28 has three operating modes: a constant power mode in which it operates so that the power value of the sputtering power Es is constant; a constant voltage mode in which it operates so that the sputtering voltage (also called "target voltage") Vs, which is the voltage component of the sputtering power Es, is constant; and a constant current mode in which it operates so that the sputtering current (also called "target current") Is, which is the current component of the sputtering power Es, is constant.Here, it is set to operate in the constant power mode.

[0038] Additionally, a cathode filament 30 serving as a thermionic electron emitting means is provided in front of the magnetron sputtering cathode 24, more specifically in front of the sputtering surface of the target 242. This cathode filament 30 is a linear body having a diameter of, for example, about 1 mm, and is made of, for example, tungsten (W), but may also be made of other high-melting-point metals such as molybdenum (Mo), tantalum (Ta), or carbon (C).

[0039] 4(a), the cathode filament 30 extends vertically through the center of the sputtering surface of the target 242, i.e., along the longitudinal direction of the target 242, or in other words, parallel to the sputtering surface of the target 242, when viewed from the horizontal side opposite the direction in which the magnetron sputtering cathode 24 is disposed, for example, from the side of the central axis Xa of the vacuum chamber 12. As shown in FIGS. 4(b) and 4(c), the cathode filament 30 is disposed with an appropriate distance D between it and the sputtering surface of the target 242. If the distance D is too small, for example, the cathode filament 30 may come into contact with the sputtering surface of the target 242 or the earth shield 26, which would be extremely undesirable. On the other hand, if the distance D is excessively large, the effect of the magnetic field generated by the magnet unit 244 (permanent magnet 246) around the cathode filament 30 will be weak, which will be inconvenient for inducing an arc discharge, which will be described later. For these reasons, the distance D is preferably about 5 mm to 50 mm, for example, 25 mm. The length of the cathode filament 30 is equal to or greater than the length of the target 242, and more precisely, equal to or greater than the length of an erosion region 242a of the target 242, which will be described later, for example, 500 mm. Although not shown, a tensioning mechanism is provided at either one or both ends of the cathode filament 30 as tensioning means for applying an appropriate tension to the cathode filament 30 to maintain the straight state of the cathode filament 30 (i.e., to absorb any slack in the cathode filament 30).

[0040] 1, both ends of the cathode filament 30 are connected to a heating power supply device 32, which is an example of a heating power supply means, outside the vacuum chamber 12. The cathode filament 30 is supplied with AC cathode power Ec as heating power from the heating power supply device 32. This heats the cathode filament 30 to 2000°C or higher, causing thermions to be emitted from the cathode filament 30. Note that the cathode power Ec is not limited to AC power, and may be DC power.

[0041] Furthermore, one end of the cathode filament 30 is connected outside the vacuum chamber 12 to an arc discharge power supply 34, which is an example of an arc discharge power supply means. The arc discharge power Ed, which is DC power at a negative potential with respect to the ground potential, is supplied to the cathode filament 30 from the arc discharge power supply 34. In other words, the vacuum chamber 12 serves as the anode, or more precisely, the earth shield 26 serves as the anode, and the cathode filament 30 serves as the cathode, and the arc discharge power Ed is supplied to both of them. The arc discharge power supply 34 is, for example, a constant voltage power supply, and its maximum output voltage, i.e., the maximum value of the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, is, for example, 100 V.

[0042] A current detector 36 serving as an arc discharge current detection means is provided between the arc discharge power supply device 34 and ground. This current detector 36 detects the arc discharge current Id, which is a current component of the arc discharge power Ed. The value of the arc discharge current Id detected by the current detector 36 is provided to a heating controller 38 serving as an example of heating power control means.

[0043] The heating controller 38 controls the heating power supply device 32 so that the value of the arc discharge current Id detected by the current detector 36 becomes constant, that is, so that the arc discharge current Id becomes constant, and more specifically, controls the cathode power Ec via the heating power supply device 32. This allows the heating temperature of the cathode filament 30, that is, the amount of thermoelectrons emitted by the cathode filament 30, to be appropriately adjusted. In other words, the amount of thermoelectrons emitted by the cathode filament 30 is automatically controlled using the arc discharge current Id as a parameter so that the arc discharge current Id becomes constant.

[0044] Focusing on the inside of the position where the cathode filament 30 is provided in the vacuum chamber 12, multiple workpieces 100 are arranged within the vacuum chamber 12. Specifically, the workpieces 100 are arranged at equal intervals along the circumferential direction of a circle centered on the central axis Xa of the vacuum chamber 12. Each workpiece 100 has, for example, an elongated, approximately cylindrical or columnar shape, and is held by a holder 40 serving as a holding means so as to extend vertically, i.e., in a direction along the central axis Xa of the vacuum chamber 12. Each holder 40 is coupled via a gear mechanism 42 to the vicinity of the periphery of a disk-shaped revolution table 44. The center of the revolution table 44 is located on the central axis Xa of the vacuum chamber 12, and one end of a rotation shaft 46 extending along the central axis Xa of the vacuum chamber 12 is fixed to the center of the revolution table 44. The other end of the rotary shaft 46 is connected to a shaft 48a of a motor 48 serving as a rotary drive means outside the vacuum chamber 12.

[0045] That is, when the motor 48 is driven and the shaft 48a of the motor 48 rotates in the direction indicated by the arrow 200 in FIG. 1, the revolving table 44 rotates in the same direction, i.e., in the direction indicated by the arrow 200 in FIG. 2. Accordingly, each workpiece 100 rotates about the central axis Xa of the vacuum chamber 12, or in other words, revolves. At the same time, due to the rotational drive force transmission action of each gear mechanism 42, each holder 40 rotates about a vertical line Xb passing through the holder 40, for example, in the direction indicated by the arrow 202 in FIGS. 1 and 2. Then, as the holder 40 itself rotates, the workpiece 100 also rotates in the same direction, or in other words, rotates on its own axis. In short, each workpiece 100 revolves around its own axis. The revolution path diameter (PCD) of the workpiece 100 is, for example, approximately 600 mm. The revolution speed of the workpieces 100 (the rotation speed of the revolution table 44) is, for example, 0.5 rpm to 1 rpm. In contrast, the rotation speed of the workpieces 100 (the rotation speed of the holder 40 itself) is, for example, 30 rpm to 60 rpm, that is, 60 times the revolution speed. Note that although FIGS. 1 and 2 show an example in which the number of workpieces 100 (holders 40 and gear mechanisms 42) is 12, the number of workpieces 100 is not limited to this. Furthermore, the shape of the workpieces 100 is not limited to the aforementioned elongated, approximately columnar or approximately cylindrical shape.

[0046] Additionally, each workpiece 100 is supplied with substrate bias power Eb from a bias power supply device 50 (an example of bias power supply means) located outside the vacuum chamber 12 via the holder 40, gear mechanism 42, revolving table 44, and rotation shaft 46. This substrate bias power Eb is a so-called asymmetric bipolar pulse power in which its voltage component, a substrate bias voltage Vb, alternates between a high-level value of positive potential with respect to ground potential and a low-level value of negative potential with respect to ground potential. The high-level value of the substrate bias voltage Vb is constant, e.g., +37 V with respect to ground potential. Meanwhile, the low-level value of the substrate bias voltage Vb can be set arbitrarily, and the average value (DC equivalent value) of the substrate bias voltage Vb is determined by this low-level value. Furthermore, the frequency of the substrate bias power Eb can also be set arbitrarily, e.g., within a range of 50 kHz to 250 kHz. The duty ratio of the substrate bias power Eb (the ratio of the period during which the substrate bias voltage Vb is at a high level in one cycle of the substrate bias voltage Vb) can also be set arbitrarily. Here, the frequency of the substrate bias power Eb is set to, for example, 100 kHz, and the duty ratio is set to, for example, 30%. Note that the bias power supply device 50 may be configured to specify the effective value of the substrate bias voltage Vb instead of the average value of the substrate bias voltage Vb.

[0047] Furthermore, a carbon heater 52, for example, is provided as a temperature control means at an appropriate position inside the wall forming the side surface of the vacuum chamber 12, but outward from the revolution path of each of the workpieces 100, 100, ..., for example, on the opposite side of the central axis Xa of the vacuum chamber 12 from the position where the magnetron sputtering cathode 24 is provided (the left side position in Figures 1 and 2). This carbon heater 52 is connected to a heater heating power supply device (not shown) outside the vacuum chamber 12. The carbon heater 52 receives a supply of DC or AC heater heating power from the heater heating power supply device and generates heat, thereby heating the inside of the vacuum chamber 12, and in particular the workpieces 100, 100, ... As shown in FIG. 2, the portion 12b of the wall of the vacuum chamber 12 where the carbon heater 52 is provided is also structured appropriately for providing the carbon heater 52, similar to the portion 12a where the magnetron sputtering cathode 24 and earth shield 26 are provided.

[0048] 1, a gas inlet 54 for introducing various gases, such as an inert gas, into the vacuum chamber 12 is provided at an appropriate position within the vacuum chamber 12, preferably near the cathode filament 30. A gas inlet pipe 56 is connected to the gas inlet 54 outside the vacuum chamber 12, and a plurality of branch pipes 58, 62, and 64, three in this example, are connected to the gas inlet pipe 56.

[0049] One of the branch pipes 58, 62, and 64, for example, the uppermost branch pipe 58 in FIG. 1 , is a pipe for introducing an inert gas into the vacuum chamber 12 and is connected to a supply source (not shown) of the inert gas. This branch pipe 58 for introducing the inert gas is provided with an on-off valve 58a as an on-off means for opening and closing the branch pipe 58, and a mass flow controller 58b as a flow rate control means for controlling the flow rate Qi of the inert gas flowing through the branch pipe 58. The branch pipe 58 for introducing the inert gas, including the on-off valve 58a and the mass flow controller 58b, cooperates with the gas introduction pipe 56 to constitute an example of an inert gas introduction means. The inert gas may be, for example, argon (Ar) gas.

[0050] Of the branch pipes 58, 62, and 64, for example, the branch pipe 62, which is the second from the top in FIG. 1 , is a pipe for introducing a first reactive gas, which is a material for the target coating, particularly a material for the reactive film, into the vacuum chamber 12. The first reactive gas is supplied from a supply source (not shown). The branch pipe 62 for introducing the first reactive gas is also provided with an on-off valve 62a as an on-off means for opening and closing the branch pipe 62, and a mass flow controller 62b as a flow rate control means for controlling the flow rate Qr1 of the first reactive gas flowing through the branch pipe 62. The branch pipe 62 for introducing the first reactive gas, including the on-off valve 62a and the mass flow controller 62b, cooperates with the gas introduction pipe 56 to constitute an example of a first reactive gas introduction means. Note that, as the first reactive gas, an appropriate gas is used depending on the type of the target reactive film, along with the second reactive gas introduced into the vacuum chamber 12 via the remaining branch pipe 64.

[0051] The remaining branch pipe 64, i.e., the lowest branch pipe 64 in FIG. 1 of the branch pipes 58, 62, and 64, is a pipe for introducing a second reactive gas, which is a material for the reactive film, into the vacuum chamber 12, and the second reactive gas is supplied from a supply source (not shown). This branch pipe 64 for introducing the second reactive gas is also provided with an on-off valve 64a as an on-off means for opening and closing the branch pipe 64, and a mass flow controller 64b as a flow rate control means for controlling the flow rate Qr2 of the second reactive gas flowing through the branch pipe 64. The branch pipe 64 for introducing the second reactive gas, including the on-off valve 64a and the mass flow controller 64b, cooperates with the gas introduction pipe 56 to constitute an example of a second reactive gas introduction means. The branch pipe 64, together with the branch pipe 62 for introducing the first reactive gas, cooperates with the gas introduction pipe 56 to constitute an example of a reactive gas introduction means.

[0052] Although not shown, strictly speaking, in addition to the branch pipes 58, 62, and 64, a branch pipe is provided for introducing hydrogen (H) gas, which serves as a discharge cleaning gas (described later), particularly as a chemical cleaning gas, into the vacuum chamber 12. This branch pipe for introducing hydrogen gas is also provided with an on-off valve as an on-off means for opening and closing the branch pipe, and a mass flow controller as a flow rate control means for controlling the flow rate Qc of hydrogen gas flowing through the branch pipe.

[0053] In addition, a pressure gauge 66 is provided at an appropriate position within the vacuum chamber 12, for example, at an appropriate position in the upper part of the vacuum chamber 12, so that a gauge portion (measurement portion) 66a of the pressure gauge 66 is disposed. The pressure gauge 66 is a pressure measurement means for measuring the pressure within the vacuum chamber 12, or more precisely, the pressure P at the position where the gauge portion 66a is disposed. The pressure P measured by the pressure gauge 66 is provided to a total gas flow controller 68, which is an example of a total reactive gas flow control means, located outside the vacuum chamber 12. Note that, for example, a diaphragm vacuum gauge capable of measuring absolute pressure with relatively high accuracy and high resolution is used as the pressure gauge 66. The position where the gauge portion 66a is disposed is not limited to the upper part of the vacuum chamber 12, and may be any position that is less affected by the plasma 300, which will be described later.

[0054] The total gas flow rate controller 68 cooperates with the gas flow rate ratio controller 70 to keep the gas flow rate ratio Rq (which may be Qr2 / Qr1 or Qr1 / Qr2), which is the ratio between the flow rate Qr1 of the first reactive gas and the flow rate Qr2 of the second reactive gas into the vacuum chamber 12, constant so that the pressure P measured by the pressure gauge 66 remains constant, i.e., so that the pressure P inside the vacuum chamber 12 remains constant. The total gas flow rate controller 68 controls the total flow rate, which is the sum of the flow rate Qr1 of the first reactive gas and the flow rate Qr2 of the second reactive gas, or in other words, the total gas flow rate Qa (=Qr1+Qr2), and more specifically, individually controls the mass flow controller 62b for introducing the first reactive gas and the mass flow controller 64b for introducing the second reactive gas. That is, using the pressure P inside the vacuum chamber 12 as a parameter, the total gas flow rate Qa is controlled while the gas flow rate ratio Rq is kept constant so that the pressure P inside the vacuum chamber 12 is constant; in other words, the flow rate Qr1 of the first reactive gas and the flow rate Qr2 of the second reactive gas are automatically controlled individually so that this is the case.

[0055] Specifically, the total gas flow rate controller 68 instructs the gas flow ratio controller 70 to adjust the total gas flow rate Qa in accordance with the pressure P in the vacuum chamber 12, for example, to increase the total gas flow rate Qa when the pressure P is lower than a preset target value, and to decrease the total gas flow rate Qa when the pressure P is higher than the target value. In accordance with the instruction from the total gas flow rate controller 68, the gas flow rate ratio controller 70 individually controls the flow rate Qr1 of the first reactive gas and the flow rate Qr2 of the second reactive gas while maintaining the gas flow ratio Rq at a preset set value, i.e., individually controls the mass flow controller 62b for introducing the first reactive gas and the mass flow controller 64b for introducing the second reactive gas.

[0056] At this time, the flow rate Qi of the inert gas into the vacuum chamber 12 is kept constant, as will be described later. The effective exhaust speed at the exhaust port 14 of the vacuum chamber 12 is kept constant. Furthermore, the sputtering power Es is kept constant. Additionally, as described above, the arc discharge power Ed is kept constant, specifically, the arc discharge voltage Vd is kept constant, and the cathode power Ec is controlled so that the arc discharge current Id is kept constant, i.e., the amount of thermoelectrons emitted from the cathode filament 30 is controlled. The substrate bias voltage Vb is kept constant.

[0057] The gas flow rate ratio Rq can be arbitrarily set by a setting unit (not shown). This setting unit is provided in, for example, the gas flow rate ratio controller 70. The total gas flow rate controller 68 and the gas flow rate ratio controller 70 cooperate with the pressure gauge 66 to constitute an example of reactive gas flow rate control means. The configuration of this reactive gas flow rate control means is not limited to this, and for example, the total gas flow rate controller 68 and the gas flow rate ratio controller 70 may be integrated into one element.

[0058] The controllable range of the gas flow ratio Rq is determined by the respective maximum controllable flow rates of the mass flow controller 62b for introducing the first reactive gas and the mass flow controller 64b for introducing the second reactive gas. For example, if the maximum controllable flow rate of the mass flow controller 62b for introducing the first reactive gas is 100 mL / min and the maximum controllable flow rate of the mass flow controller 64b for introducing the second reactive gas is 100 mL / min, the minimum controllable flow rate of each mass flow controller 62b and 64b is limited to 2% of the maximum controllable flow rate, and therefore the controllable range of the gas flow ratio Rq is 0.02 to 50. Furthermore, if the maximum controllable flow rate of the mass flow controller 62b for introducing the first reactive gas is 50 mL / min and the maximum controllable flow rate of the mass flow controller 64b for introducing the second reactive gas is 100 mL / min, the controllable range of the gas flow ratio Rq is 0.01 to 25. Conversely, if the maximum controllable flow rate of the mass flow controller 62b for introducing the first reactive gas is 100 mL / min and the maximum controllable flow rate of the mass flow controller 64b for introducing the second reactive gas is 50 mL / min, the controllable range of the gas flow ratio Rq is 0.04 to 100.

[0059] As will be described later, since the gas flow ratio Rq is related to the composition ratio of the target reactive film, the maximum controllable flow rate of each of the mass flow controllers 62b and 64b is appropriately selected in order to control the composition ratio with high precision, i.e., each of the mass flow controllers 62b and 64b is selected with appropriate specifications that include the maximum controllable flow rate. In addition, the appropriate values ​​of the flow rate Qr1 of the first reactive gas and the flow rate Qr2 of the second reactive gas, which are elements of the gas flow ratio Rq, vary depending on various conditions such as the configuration of the exhaust means (exhaust system) including the vacuum pump 18, and therefore, each of the mass flow controllers 62b and 64b with appropriate specifications is selected taking this into consideration.

[0060] Furthermore, although detailed explanation including illustrations is omitted, a shutter is provided between the cathode filament 30 and the workpiece 100 located closest to the cathode filament 30 (i.e., the portion of the workpiece 100 in its orbital path that is closest to the cathode filament 30). This shutter appropriately transitions between an open state that exposes the sputtering surface of the target 242 of the magnetron sputtering cathode 24 to the space in which the workpiece 100 is placed, and a closed state that shields it from the space.

[0061] The magnetron sputtering apparatus 10 configured as described above can form various reactive films on the surface of the workpiece 100, and in particular can form multi-component reactive films of ternary (element) or higher systems. For example, the case of forming a titanium carbonitride film, which is one of the ternary reactive films, as the reactive film will be described. In this case, a target 242 made of titanium with a purity of 3N or higher is used. Nitrogen gas with a purity of 5N or higher is used as the first reactive gas, and high-purity dissolved acetylene gas (solvent: DMF) with a purity of 3N or higher is used as the second reactive gas.

[0062] Then, first, the workpiece 100 is placed in the vacuum chamber 12, that is, attached to the holder 40. Then, the inside of the vacuum chamber 12 is vacuumed by the vacuum pump 18 to a pressure of 2×10 -3 The air is evacuated until a pressure P of about Pa is reached, and so-called vacuuming is performed. Thereafter, motor 48 is driven, and rotation and revolution of workpiece 100 begin. At the same time, heater heating power is supplied to carbon heater 52, and workpiece 100 is heated to, for example, about 200°C. As a result, impurity gases contained in workpiece 100 are discharged, and so-called degassing is performed.

[0063] After this degassing process is performed for a predetermined time (for example, about 30 minutes to 1 hour), a discharge cleaning process is performed to clean the surface of the workpiece 100. To do this, the supply of heater heating power to the carbon heater 52 is stopped. Then, cathode power Ec is supplied to the cathode filament 30. In response to this, the cathode filament 30 is heated and thermoelectrons are emitted from the cathode filament 30. At the same time, arc discharge power Ed is supplied to the cathode filament 30. That is, the earth shield 26 serves as the anode and the cathode filament 30 serves as the cathode, and arc discharge power Ed is supplied to both. As a result, thermoelectrons emitted from the cathode filament 30, which is the cathode, are accelerated toward the earth shield 26, which is the anode. In this state, argon gas, which serves as an inert gas, is introduced into the vacuum chamber 12. The accelerated thermoelectrons then collide with argon gas particles (argon particles), and the impact ionizes the argon particles, inducing plasma 300. That is, argon gas functions as a discharge gas for inducing plasma 300. Furthermore, plasma 300 contains a mixture of ions, electrons, and neutral particles.

[0064] Here, a magnetic field is formed by the permanent magnet 246 described above near the sputtering surface of the target 242, including around the cathode filament 30. The thermoelectrons accelerated from the cathode filament 30 toward the earth shield 26 undergo a spiral motion due to the effect of this magnetic field. As a result, the frequency with which the thermoelectrons collide with argon particles increases, and the plasma 300 becomes denser. The discharge mode of such plasma 300 is a low-voltage, high-current arc discharge. At the same time, hydrogen gas is introduced into the vacuum chamber 12 as a discharge cleaning gas (chemical cleaning gas). Particles of this hydrogen gas (hydrogen particles) are decomposed by the plasma 300, and some of them are ionized.

[0065] The plasma 300 caused by the arc discharge is induced when the pressure P inside the vacuum chamber 12 is in the range of 0.01 Pa to 1 Pa, for example; that is, it can be induced even when the pressure P is relatively low. Here, the pressure P inside the vacuum chamber 12 is set to, for example, 0.150 Pa. The flow rate Qi of the argon gas is set to, for example, 50 mL / min, and the flow rate Qc of the hydrogen gas is set to, for example, 150 mL / min. The arc discharge power Ed is set to, for example, 500 W. More specifically, the cathode power Ec is controlled so that the arc discharge current Id is 10 A with the arc discharge voltage Vd set to 50 V. This stabilizes the density of the plasma 300 caused by the arc discharge.

[0066] While the plasma 300 is induced by this arc discharge, the substrate bias power Eb is supplied to the workpiece 100. That is, the vacuum chamber 12 serves as the anode, and the workpiece 100 serves as the cathode, and the substrate bias power Eb is supplied to both of them. The substrate bias voltage Vb (average value), which is the voltage component of the substrate bias power Eb, is set to, for example, -600 V. As described above, the frequency of the substrate bias power Eb is set to, for example, 100 kHz, and the duty ratio is set to, for example, 30%. The shutter described above is kept closed until the plasma 300 stabilizes. Then, after the plasma 300 stabilizes, the shutter is opened.

[0067] As a result, argon particles in the plasma 300 (strictly speaking, argon ions, more precisely, argon ions present near the surface of the workpiece 100) and hydrogen particles in the plasma 300 (strictly speaking, hydrogen ions, more precisely, hydrogen ions present near the surface of the workpiece 100) are accelerated toward the workpiece 100 and actively impinge on the surface of the workpiece 100. As a result, a natural oxide layer and an organic contaminant layer on the surface of the workpiece 100 are removed by a sputtering action caused by the argon ions colliding with the surface of the workpiece 100 and a chemical reaction action caused by the hydrogen ions, i.e., a discharge cleaning process is performed. As described above, since the workpiece 100 rotates and revolves around its axis, the discharge cleaning process is (essentially) performed while the workpiece 100 is exposed to the plasma 300 during the process. In the discharge cleaning process, argon gas also functions as a discharge cleaning gas, and particularly as a physical cleaning gas.

[0068] After this discharge cleaning process is performed for a predetermined time (e.g., 20 minutes), a pre-sputtering process is performed to clean the sputtering surface of the target 242. To this end, the introduction of hydrogen gas into the vacuum chamber 12 is stopped, and the shutter is closed. The flow rate Qi of the argon gas is set to, for example, 100 mL / min. At the same time, sputtering power Es is supplied to the magnetron sputtering cathode 24 including the target 242. Specifically, sputtering power Es is supplied to both the earth shield 26 as the anode and the magnetron sputtering cathode 24 as the cathode. This sputtering power Es is set to 8 kW. Furthermore, the angle θ of the conductance valve 22 is set to 40 degrees, i.e., the effective pumping speed is set according to the angle θ of the conductance valve 22. The pressure P in the vacuum chamber 12 is set to 0.190 Pa. In addition, the arc discharge power Ed is set to 1000 W, and more specifically, the cathode power Ec is controlled so that the arc discharge current Id is 20 A with the arc discharge voltage Vd set to 50 V. The shutter is maintained in a closed state. The substrate bias power Eb may continue to be supplied to the workpiece 100, or may not be supplied.

[0069] In this pre-sputtering process, similar to the discharge cleaning process, plasma 300 is induced by arc discharge; in other words, the plasma 300 continues to be induced by the arc discharge. Then, sputtering power Es is supplied to the magnetron sputtering cathode 24, thereby inducing magnetron plasma. The discharge mode of this magnetron plasma is a high-voltage, low-current glow discharge. That is, in addition to the plasma 300 by arc discharge, magnetron plasma by glow discharge is induced. In other words, the plasma 300 by arc discharge is a mode that includes magnetron plasma by glow discharge. The magnetron plasma by glow discharge is induced so as to adhere to the sputtering surface of the target 242 due to the effect of the magnetic field generated by the permanent magnet 246 described above. This magnetron plasma also contains a mixture of ions, electrons, and neutral particles, just like the plasma 300 caused by arc discharge. However, it is impossible to distinguish whether the ions, electrons, and neutral particles constitute the magnetron plasma or the plasma 300 caused by arc discharge.

[0070] Then, argon particles in the plasma 300, particularly argon ions, collide with the sputtering surface of the target 242, sputtering the sputtering surface. This cleans the sputtering surface of the target 242, i.e., a pre-sputtering process is performed. Note that the sputtering region, which is the region of the target 242 that is the target of sputtering, is limited to the sputtering surface of the target 242, or in other words, the aforementioned earth shield 26 is provided to limit this.

[0071] After this pre-sputtering process is performed for a predetermined time (e.g., 3 minutes), a film-forming process is performed to form a titanium film as an intermediate layer on the surface of the workpiece 100. In this titanium film-forming process, for example, the pressure P in the vacuum chamber 12 is set to 0.200 Pa. The substrate bias voltage Vb (average value) is set to -100 V. The argon gas flow rate Qi, sputtering power Es, angle θ of the conductance valve 22, and arc discharge power Ed are set to the same values ​​(conditions) as those used during pre-sputtering. Then, the shutter is opened.

[0072] As a result, similar to the pre-sputtering process, argon ions in the plasma 300 collide with the sputtering surface of the target 242, sputtering the sputtering surface. The sputtered particles, i.e., titanium particles (strictly speaking, some of the titanium particles), sputtered from the sputtering surface of the target 242 are ionized by the plasma 300. The ionized titanium ions, specifically, titanium ions present near the surface of the workpiece 100, are accelerated toward the workpiece 100. At the same time, argon particles in the plasma 300, specifically, argon ions, and more specifically, argon ions present near the surface of the workpiece 100, are also accelerated toward the workpiece 100. The titanium particles containing the titanium ions then adhere to and deposit on the surface of the workpiece 100, forming a titanium film as an intermediate layer on the surface of the workpiece 100. In particular, the bonding force of the titanium ions contributes to the densification of the titanium film. In addition, the density of the titanium film is improved by the bombardment effect caused by argon ions colliding with the surface of the object 100 to be processed.

[0073] Titanium particles sputtered from the sputtering surface of the target 242 pass through the space of the extremely high-density plasma 300 on their way toward the workpiece 100. This activates the titanium particles and efficiently ionizes them. Similarly, argon particles are also activated and efficiently ionized. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece 100, thereby further densifying the titanium film formed on the surface of the workpiece 100. In addition, in the titanium film formation process, as in the discharge cleaning process described above, the workpiece 100 is (substantially) subjected to the film formation process while it is exposed to the plasma 300 during its rotation and revolution.

[0074] After the film formation process for this titanium film as the intermediate layer is carried out for a predetermined time (the time required to form a titanium film of a predetermined thickness), a film formation process for forming the target titanium carbonitride film is carried out. In the film formation process for this titanium carbonitride film, in addition to the conditions for the film formation process for the titanium film as the intermediate layer, nitrogen gas as a first reactive gas and acetylene gas as a second reactive gas are simultaneously introduced into vacuum chamber 12.

[0075] Particles of the nitrogen gas and acetylene gas introduced into the vacuum chamber 12 are decomposed by the plasma 300, and some of them are ionized. Then, the ionized nitrogen ions, specifically, nitrogen ions present near the surface of the workpiece 100, and the ionized acetylene ions, specifically, acetylene ions present near the surface of the workpiece 100, are accelerated toward the workpiece 100. At this time, titanium ions and argon ions, specifically, titanium ions and argon ions present near the surface of the workpiece 100, are also accelerated toward the workpiece 100. In particular, titanium particles containing titanium ions, nitrogen particles containing nitrogen ions, and acetylene particles containing acetylene ions adhere to the surface of the workpiece 100 and react with each other, forming a titanium carbonitride film, which is a reaction film composed of titanium particles, nitrogen particles, and acetylene particles, on the surface of the workpiece 100. Strictly speaking, a titanium carbonitride film containing hydrogen is formed. Additionally, the density of the titanium carbonitride film is improved by the bombardment effect caused by argon ions colliding with the surface of the object 100 to be processed.

[0076] In addition, titanium particles sputtered from the sputtering surface of the target 242 pass through the space of the extremely high-density plasma 300 on their way toward the workpiece 100. This causes the titanium particles to be more activated and ionized more efficiently. Similarly, argon particles, nitrogen particles, and acetylene particles are also more activated and ionized more efficiently. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece 100, thereby further densifying the titanium carbonitride film formed on the surface of the workpiece 100. In the film formation process of this titanium carbonitride film, the workpiece 100 is (substantially) subjected to the film formation process while it is exposed to the plasma 300 during its rotation and revolution.

[0077] 4, when attention is paid to the sputtering surface of the target 242, a region 242a of the sputtering surface, which is roughly a rectangular loop (or an elliptical loop) that follows the gap 246c of the permanent magnet 246, is more efficiently (concentratedly) sputtered. This is because the density of the plasma 300 is higher in the space facing this region 242a. As a result, sputtering marks appear in this region 242a, forming a so-called erosion region.

[0078] After this titanium carbonitride film formation process is performed for a predetermined time (the time required to form a titanium carbonitride film of a predetermined thickness), the shutter is closed. The introduction of argon gas, nitrogen gas, and acetylene gas into the vacuum chamber 12 is then stopped. At the same time, the supply of sputtering power Es to the magnetron sputtering cathode 24 is stopped, and the supply of cathode power Ec and arc discharge power Ed to the cathode filament 30 is stopped. This causes the plasma 300 to disappear. Furthermore, the supply of substrate bias power Eb to the workpiece 100 is stopped. Then, with the vacuum chamber 12 maintained at a high vacuum by the vacuum pump 18, the vacuum chamber 12 is allowed to cool to a predetermined temperature (e.g., 150°C), i.e., an appropriate cooling period is allowed. Then, the motor 48 is stopped, and the rotation and revolution of the workpiece 100 are stopped. Thereafter, the inside of the vacuum chamber 12 is opened to the outside, and the workpiece 100 is taken out from the vacuum chamber 12. This completes a series of processes including the film formation process of the titanium carbonitride film.

[0079] In the explanation of this series of processes, particularly in the explanation of the titanium carbonitride film formation process, the total gas flow rate controller 68 and the gas flow rate ratio controller 70 have not been specifically mentioned. However, as described above, the total gas flow rate controller 68 and the gas flow rate ratio controller 70 cooperate to control the total gas flow rate Qa, which is the sum of the flow rate Qr1 of nitrogen gas as the first reactive gas and the flow rate Qr2 of acetylene gas, while maintaining the gas flow rate ratio Rq, which is the ratio between the flow rate Qr1 of nitrogen gas as the first reactive gas and the flow rate Qr2 of acetylene gas, so that the pressure P inside the vacuum chamber 12 remains constant; more specifically, they individually control the mass flow controller 62b for introducing the first reactive gas and the mass flow controller 64b for introducing the second reactive gas. That is, with the pressure P inside the vacuum chamber 12 as a parameter, the total gas flow rate Qa is controlled while the gas flow rate ratio Rq is kept constant so that the pressure P inside the vacuum chamber 12 is constant, that is, the nitrogen gas flow rate Qr1 and the acetylene gas flow rate Qr2 are automatically controlled individually so that this is the case. Hereinafter, the nitrogen gas flow rate Qr1 may be represented by the symbol Q[N2], and the acetylene gas flow rate Qr2 may be represented by the symbol Q[C2H2].

[0080] In the titanium carbonitride film deposition process, the flow rate Qi of argon gas as an inert gas is kept constant. At the same time, the angle θ of the conductance valve 22 is kept constant, i.e., the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 is kept constant. Furthermore, the sputtering power Es is kept constant, and the arc discharge power Wb is kept constant. Furthermore, the substrate bias voltage Vb (average value) is also kept constant.

[0081] For example, as a comparison with this embodiment, consider a configuration in which the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] are both constant in the titanium carbonitride film deposition process, i.e., a configuration in which the gas flow rate ratio Rq (=Q[C2H2] / Q[N2]) is constant and the total gas flow rate Qa (=Q[N2]+Q[C2H2]) is constant. In this configuration, the sputtering rate of the sputtering surface of target 242 changes, resulting in the disadvantage that the desired titanium carbonitride film cannot be reproduced, particularly in terms of color tone.

[0082] That is, the color tone of the titanium carbonitride film depends on the composition ratio of the titanium carbonitride film. Based on this, when the sputtering surface of the target 242 after the titanium carbonitride film formation process was observed, it was confirmed that the titanium carbonitride film was attached to the non-eroded region of the sputtering surface other than the eroded region 242a, while the titanium carbonitride film was not attached to the eroded region 242a. It was also confirmed that carbonitriding (or a phenomenon similar to carbonitriding) occurred near the boundary between the eroded region 242a and the non-eroded region, and that the appearance of this phenomenon varied from batch to batch. As mentioned above, extremely high-density plasma 300 was induced near the sputtering surface of the target 242, particularly in the space facing the eroded region 242a, making the space chemically very active. For this reason, it is believed that carbonitriding occurs particularly near the boundary between the eroded region 242a and the non-eroded region of the sputtering surface of the target 242. Since the carbonitriding process varies from batch to batch, the sputtering rate of the sputtered surface of target 242 varies from batch to batch, and the balance between the amount of nitrogen particles and carbon particles relative to the amount of sputtered particles varies from batch to batch. As a result, the composition ratio of the titanium carbonitride film changes, and it is thought that this makes it impossible to reproduce the color tone of the titanium carbonitride film.

[0083] In contrast, according to this embodiment, in the film formation process for a titanium carbonitride film, the gas flow ratio Rq, which is the ratio between the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2], is maintained constant so that the pressure P in the vacuum chamber 12 is constant. The total gas flow rate Qa, which is the sum of the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2], is controlled. In other words, the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] are automatically controlled individually. At this time, the flow rate Qi of the argon gas serving as the inert gas is maintained constant. The angle θ of the conductance valve 22 is also maintained constant, which means that the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 is maintained constant. Furthermore, the sputtering power Es and the arc discharge power Wb are maintained constant. The substrate bias voltage Vb (average value) is also maintained constant.

[0084] According to this embodiment, the sputtering rate of the sputtering surface of the target 242 is kept constant, the balance of the amount of nitrogen particles and carbon particles relative to the amount of titanium particles (sputter particles) is kept constant, and the balance of the amount of nitrogen particles and carbon particles (between each other) is kept constant. This improves the reproducibility of the titanium carbonitride film, particularly the reproducibility of color tone. This will be explained in detail below.

[0085] First, in this example, an experiment was conducted to confirm how the pressure P in the vacuum chamber 12, the nitrogen gas flow rate Q [N2], and the acetylene gas flow rate Q [C2H2] changed during the titanium carbonitride film deposition process. The results are shown in Figure 5. Figure 5 shows an example of log data recording the pressure P in the vacuum chamber 12, the nitrogen gas flow rate Q [N2], and the acetylene gas flow rate Q [C2H2] in chronological order. For reference, Figure 5 also shows log data for the sputtering power Es, the sputtering voltage Vs, which is the voltage component of the sputtering power Es, and the sputtering current Is, which is the current component of the sputtering power Es. Figure 5 also shows log data for the arc discharge current Id for reference. The horizontal axis in Figure 5 represents time, with each division on the horizontal axis corresponding to 10 minutes. The time t0 on the horizontal axis of Figure 5 represents the time when various controls, including the individual automatic controls of the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2], are initiated. Meanwhile, the vertical axis of Figure 5 represents the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2]. Therefore, the scales on the vertical axis are irrelevant to the pressure P in the vacuum chamber 12, the sputtering power Es, the sputtering voltage Vs, the sputtering current Is, and the arc discharge current Id, and only show the transition states of each.

[0086] In this experiment, the argon gas flow rate Qi [Ar] was set to 100 mL / min (constant), the conductance valve 22 angle θ was set to 40 degrees (constant), the sputtering power Es was set to 8 kW (constant), and the substrate bias voltage Vb (average value) was set to -100 V (constant). From the start of the titanium carbonitride film deposition process to time t0, the nitrogen gas flow rate Q [N2] was set to 27 mL / min (constant), and the acetylene gas flow rate Q [C2H2] was set to 13.5 mL / min (constant), i.e., the gas flow ratio Rq was set to 0.5 (constant). The pressure P in the vacuum chamber 12 at this time was determined as the process progressed, and was, for example, approximately 0.200 Pa. After time t0, the pressure P in the vacuum chamber 12 was kept constant at 0.210 Pa. More precisely, the gas flow rate ratio Rq was kept constant at 0.5, and the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] were automatically controlled so that the pressure P in the vacuum chamber 12 remained constant at 0.210 Pa. This automatic control caused the nitrogen gas flow rate Q[N2] to vary between approximately 24 mL / min and 32 mL / min, averaging approximately 28 mL / min. The acetylene gas flow rate Q[C2H2] also varied between approximately 12 mL / min and 16 mL / min, averaging approximately 14 mL / min. Additionally, from the start of the titanium carbonitride film deposition process to time t0, the arc discharge current Id was set to 15 A (constant), more precisely, the arc discharge voltage Vd was set to 50 V (constant), and the cathode power Ec was automatically controlled so that the arc discharge current Id was 15 A (constant); that is, the arc discharge power Ed was set to 750 W (constant). Then, after time t0, the arc discharge current Id was set to 20 A (constant), more precisely, the arc discharge voltage Vd was set to 50 V (constant), and the cathode power Ec was automatically controlled so that the arc discharge current Id was 20 A (constant), that is, the arc discharge power Ed was set to 1000 W (constant). Incidentally, the time from the start of the titanium carbonitride film deposition process to time t0 was, for example, about 3 to 4 minutes, which is a preparatory period for smoothly starting the automatic control mentioned here.

[0087] In the experimental results shown in Figure 5, for example, if we focus on the nitrogen gas flow rate Q[N2] after time t0, we see that the nitrogen gas flow rate Q[N2] varies within a range of approximately 24 mL / min to 32 mL / min, as described above, and occasionally decreases significantly. The period during which the nitrogen gas flow rate Q[N2] decreases significantly is not constant but varies from several minutes to over ten minutes. Furthermore, the period during which the nitrogen gas flow rate Q[N2] remains significantly decreased lasts for several seconds, specifically, approximately 2 to 3 seconds.

[0088] Focusing on the acetylene gas flow rate Q[C2H2] after time t0, the acetylene gas flow rate Q[C2H2] fluctuates between approximately 12 mL / min and 16 mL / min, as described above, with occasional large decreases. This change in the acetylene gas flow rate Q[C2H2] is synchronized with the change in the nitrogen gas flow rate Q[N2]. Even when the acetylene gas flow rate Q[C2H2] and the nitrogen gas flow rate Q[N2] change in synchronization with each other, the gas flow rate ratio Rq, which is the ratio between the two, remains constant at 0.5. In other words, the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] are automatically controlled independently as described above.

[0089] Furthermore, focusing on the pressure P in the vacuum chamber 12 after time t0, the pressure r in the vacuum chamber 12 is 0.210 Pa (constant). That is, so that the pressure P in the vacuum chamber 12 after time t0 is 0.210 Pa (constant), the gas flow rate ratio Rq, which is the mutual ratio between the flow rate Q[N2] of nitrogen gas and the flow rate Q[C2H2] of acetylene gas, is maintained at 0.5 (constant), and the flow rates Q[N2] of nitrogen gas and Q[C2H2] of acetylene gas are automatically controlled individually, so that the pressure P in the vacuum chamber 12 is 0.210 Pa (constant). In other words, the flow rates Q[N2] of nitrogen gas and Q[C2H2] of acetylene gas transition as shown in FIG.

[0090] Note that, while the arc discharge current Id after time t0 also occasionally fluctuates significantly, these changes in the arc discharge current Id are not synchronized with and are unrelated to the changes in the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2]. In contrast, the sputtering power Es after time t0 remains constant because the sputtering power supply 28, which supplies the sputtering power Es, operates in the constant power mode as described above. However, the sputtering voltage Vs, which is the voltage component of the sputtering power Es, occasionally fluctuates significantly, and these changes in the sputtering voltage Vs are generally synchronized with the changes in the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2]. The sputtering current Is, which is the current component of the sputtering power Es, changes conjugately with the sputtering voltage Vs, i.e., the sputtering current Is also roughly synchronized with the changes in the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2].

[0091] From the experimental results shown in Figure 5, particularly the transitions between the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2], it is inferred that the following phenomenon occurs in the titanium carbonitride film deposition process.

[0092] That is, in the film formation process of the titanium carbonitride film, the boundary between the erosion region 242a and the non-erosion region of the sputtering surface of the target 242 is carbonitrided as described above. As a result, the amount of titanium particles (sputtered particles) sputtered from the sputtering surface of the target 242 decreases, and accordingly, the amounts of nitrogen particles and carbon particles reacting with the titanium particles decrease. In other words, the amounts of nitrogen particles and carbon particles consumed by reaction with the titanium particles decrease. As a result, the pressure P in the vacuum chamber 12 increases (or attempts to increase). In response, the flow rate Q[N2] of the nitrogen gas and the flow rate Q[C2H2] of the acetylene gas are individually and automatically controlled so that the pressure P in the vacuum chamber 12 remains constant. As a result, the flow rate Q[N2] of the nitrogen gas and the flow rate Q[C2H2] of the acetylene gas each decrease rapidly. As a result, the ratio (relative ratio) of the amount of argon gas particles to the amount of nitrogen particles and carbon particles in the vacuum chamber 12 increases, and the frequency (number of times) of collisions between the argon gas particles, particularly argon ions, and the sputtering surface of the target 242 increases. As a result, the carbonitride layer formed on the sputtering surface of the target 242 by the carbonitriding process described above is scraped away by the argon ions, and the amount of titanium particles sputtered from the sputtering surface of the target 242 increases. The amounts of nitrogen particles and carbon particles consumed by reaction with the increased titanium particles also increase, and the pressure P in the vacuum chamber 12 decreases accordingly. In response to this, the flow rate Q[N2] of nitrogen gas and the flow rate Q[C2H2] of acetylene gas increase to compensate for the decrease in pressure P in the vacuum chamber 12, in other words, to replenish the nitrogen particles and carbon particles required to react with the increased titanium particles. It is assumed that the repetition of this phenomenon will occasionally cause the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] to each decrease significantly, as mentioned above. In this case, it is extremely important to maintain a constant gas flow rate ratio Qr between the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2]. This will maintain a constant balance between the amount of nitrogen particles and the amount of carbon particles.Furthermore, since the degree of carbonitriding of the sputtering surface of the target 242 is not constant, it is presumed that the period in which the nitrogen gas flow rate Q [N2] and the acetylene gas flow rate Q [C2H2] each decrease significantly is not constant, as mentioned above; in other words, the period in which the pressure P in the vacuum chamber 12 increases (or attempts to increase) is not constant, and therefore there is no regularity in these changes.

[0093] In this way, the pressure P within the vacuum chamber 12 is used as a parameter, and the gas flow ratio Qr, which is the ratio between the nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2], is maintained constant so that the pressure P within the vacuum chamber 12 is constant. The nitrogen gas flow rate Q[N2] and the acetylene gas flow rate Q[C2H2] are automatically controlled individually to appropriately remove the nitride layer formed on the sputtered surface of the target 242, refreshing the sputtered surface. This maintains a constant sputtering rate on the sputtered surface of the target 242, a constant balance between the amount of nitrogen particles and carbon particles relative to the amount of titanium particles (sputtered particles), and a constant balance between the amount of nitrogen particles and the amount of carbon particles. This results in improved reproducibility of the titanium carbonitride film, particularly in terms of color tone.

[0094] Furthermore, in this example, an experiment was conducted to confirm the effect of the gas flow ratio Rq on the composition ratio of the titanium carbonitride film, i.e., the relationship between the gas flow ratio Rq and the composition ratio of the titanium carbonitride film. Specifically, titanium carbonitride films were formed under different gas flow ratio Rq conditions, and the number of constituent atoms (at%) of the titanium carbonitride film formed by this film formation process was measured using an energy dispersive X-ray spectroscopy (EDS) device to determine the composition ratio of the titanium carbonitride film. The results are shown in FIG. 6. In FIG. 6, the circle symbol represents the titanium-to-carbon composition ratio C / Ti, the diamond symbol represents the nitrogen-to-carbon composition ratio C / N, and the square symbol represents the titanium-to-nitrogen composition ratio N / Ti. The conditions for forming the titanium carbonitride film in this experiment are summarized as follows. Under these conditions, a titanium carbonitride film with a thickness of approximately 0.5 μm was formed. A silicon wafer was used as the workpiece 100.

[0095] Argon gas flow rate Qi 100mL / min Gas flow ratio Rq 0.0 to 1.0 (set appropriately) Total gas flow rate Qa varies in the range of approximately 40 to 50 mL / min Conductance valve angle θ 40 degrees Vacuum chamber pressure P 0.210Pa Sputtering power Es 8kW Arc discharge power Ed 1000W (50V, 20A) Substrate bias voltage Vb -100V (average value) Film formation time: 70 minutes

[0096] 6, for example, the titanium-to-nitrogen composition ratio N / Ti tends to gradually decrease as the gas flow ratio Rq increases. The decrease becomes particularly pronounced when the gas flow ratio Rq is 0.6 or greater, but the ratio does not appear to be significantly dependent on the gas flow ratio Rq. In contrast, the titanium-to-carbon composition ratio C / Ti increases significantly as the gas flow ratio Rq increases, i.e., is roughly proportional to the gas flow ratio Rq. Similarly, the nitrogen-to-carbon composition ratio C / N also increases significantly as the gas flow ratio Rq increases, i.e., is roughly proportional to the gas flow ratio Rq. In other words, as the gas flow ratio Rq increases, or in other words, as the acetylene gas flow rate Q[C2H2] increases relatively, the carbon content of the titanium carbonitride film increases proportionally (monotonically). This indicates that the composition ratio of the titanium carbonitride film can be controlled by adjusting the gas flow rate ratio Rq.

[0097] Additionally, in this example, an experiment was conducted to confirm the effect of the gas flow ratio Rq on the color tone of the titanium carbonitride film, that is, the relationship between the gas flow ratio Rq and the color tone of the titanium carbonitride film. Specifically, a titanium carbonitride film was formed under the same conditions as in the experiment shown in Figure 6, and the color tone of the titanium carbonitride film formed by this film formation process was measured using a color difference meter (CR-400) manufactured by Konica Minolta, Inc. The results are shown in Figure 7. The circles in Figure 7 represent values ​​of lightness L * The square represents chromaticity a * ◇ represents chromaticity b * In this experiment, a mirror-finished plate (30 mm×30 mm×1 mm) made of SUS304 was used as the object to be treated 100.

[0098] In FIG. 7, for example, the brightness L * If we focus on the brightness L *The chromaticity a tends to decrease as the gas flow ratio Rq increases, specifically from 63 to 44, and the degree of decrease is smaller as the gas flow ratio Rq increases. * In the region where the gas flow ratio Rq is 0.10 or less, chromaticity b increases as the gas flow ratio Rq increases, specifically from 6 to 13, and in the region where the gas flow ratio Rq is 0.10 to 0.33, chromaticity b is roughly constant, specifically about 13, and in the region where the gas flow ratio Rq is 0.33 or more, chromaticity b decreases as the gas flow ratio Rq increases, specifically from 13 to 6, and the degree of decrease decreases as the gas flow ratio Rq increases. * tends to decrease as the gas flow rate ratio Rq increases, specifically, it decreases from 35 to 4, and the degree of decrease is smaller as the gas flow rate ratio Rq increases. In any case, it was found that the color tone of the titanium carbonitride film can be controlled by adjusting the gas flow rate ratio Rq.

[0099] FIG. 8 shows a photograph of the appearance of the titanium carbonitride film formed in the experiment shown in FIG. 7. As shown in FIG. 8, when the gas flow ratio Rq is 0, a titanium nitride film is formed instead of a titanium carbonitride film, and the titanium nitride film exhibits its characteristic bright gold color. When the gas flow ratio Rq is 0.10 to 0.50, the titanium carbonitride film exhibits a pink gold color. As the gas flow ratio Rq decreases, the film becomes more golden, or more brilliant. When the gas flow ratio Rq is 0.60 to 1.00, the titanium carbonitride film exhibits a color close to brown, and as the gas flow ratio Rq increases, the film becomes more dull. As can be seen from FIG. 8, the color tone of the titanium carbonitride film can be controlled by adjusting the gas flow ratio Rq.

[0100] As mentioned above, this example improves the reproducibility of the titanium carbonitride film, particularly the reproducibility of color tone, and an experiment was conducted to verify this. Specifically, the gas flow ratio Rq was set to 0.5 (constant), and 10 batches of titanium carbonitride film deposition were carried out under the same conditions as in the experiment shown in FIG. 7 (and FIG. 6), except that the gas flow ratio Rq was set to 0.5 (constant), and the color tone of the titanium carbonitride film formed by each batch was measured using a color difference meter (CR-400) manufactured by Konica Minolta, Inc. The results are shown in FIG. 9. The circles in FIG. 9 represent the lightness L * The square represents chromaticity a * ◇ represents chromaticity b * In this experiment, similarly to the experiment shown in FIG. 7, a mirror-finished plate-shaped body (30 mm×30 mm×1 mm) made of SUS304 was used as the object to be treated 100.

[0101] In FIG. 9, for example, the brightness L * Looking at the brightness L in 10 batches, * Mutual difference ΔL * is 0.96, which means it is roughly constant. And the chromaticity a * Similarly, the chromaticity a in 10 batches * Mutual difference Δa * is 1.23, which means it is roughly constant. Furthermore, the chromaticity b * Similarly, the chromaticity b * The mutual difference Δb * is 1.45, which means it is roughly constant. * , chromaticity a * and b * In both cases, the color tone of the titanium carbonitride film formed by each batch was generally consistent between batches. Furthermore, visual inspection revealed that the color tone of the titanium carbonitride film formed by each batch was almost the same, with no differences being observed. In other words, it was confirmed that this example provided good reproducibility for the color tone of the titanium carbonitride film. Furthermore, although not shown in the drawings, it was also confirmed that good reproducibility was provided for the film thickness of the titanium carbonitride film.

[0102] Although detailed explanation including illustrations is omitted, it has been confirmed that good reproducibility can be obtained even when forming a zirconium carbonitride (ZrCN) film. In this case, a target made of zirconium (Zr) is used as the target 242, and nitrogen gas and a hydrocarbon gas such as acetylene gas are used as the reactive gas.

[0103] As described above, according to this embodiment, even when a reaction film is formed by simultaneously introducing multiple types of reactive gases into a vacuum layer, the reaction film can be formed with high reproducibility, and particularly, high reproducibility can be obtained in terms of color tone. This will greatly contribute to the development of various fields such as decorative articles, tools, and molds.

[0104] The present embodiment is a specific example of the present invention and does not limit the technical scope of the present invention. The present invention can be applied to aspects other than the present embodiment.

[0105] For example, although the present embodiment describes the formation of a titanium carbonitride film (and a zirconium carbonitride film), the present invention can also be applied to the formation of other reactive films, particularly various reactive films of ternary or higher-component systems. The various reactive films referred to here include a titanium oxynitride (TiON) film, an oxygen-containing titanium carbonitride (TiOCN) film, and a silicon-containing titanium carbonitride (TiSiCN) film. For example, when forming a titanium oxynitride film, a titanium target 242 is used, and nitrogen gas and oxygen (O) gas are used as reactive gases. When forming a titanium oxycarbonitride film, a titanium target 242 is used, and nitrogen gas, acetylene gas, and oxygen gas are used as reactive gases, i.e., three types of gases are used. When forming a titanium silicon carbonitride film, a titanium target 242 is used, and nitrogen gas and TMS (TetraMethylSilane:Si(CH)) gas are used as reactive gases. When forming any reactive film, it is essential to keep the inert gas flow rate Qi constant, the angle θ of the conductance valve 22 constant, the sputtering power Es constant, the substrate bias voltage Vb constant, and then to control the total gas flow rate Qa while keeping the gas flow rate ratio Rq constant so that the pressure P inside the vacuum chamber 12 is constant, i.e., to individually control the flow rates Qr1, Qr2, ... of the reactive gases so that this is the case. Naturally, when three or more types of reactive gases are used, a corresponding number of branch pipes similar to branch pipes 62 and 64 are provided.

[0106] In addition, the target 242 is not limited to titanium (or zirconium) targets, but may be any suitable target depending on the target reaction film. For example, metal targets 242 include hafnium (Hf), chromium (Cr), molybdenum (Mo), tungsten (W), vanadium (V), niobium (Nb), and tantalum (Ta). Semimetal targets 242 include boron (B), aluminum (Al), carbon (C), and silicon (Si). Alloy targets 242 may also be used, including titanium-aluminum alloys (TiAl), titanium-chromium alloys (TiCr), aluminum-chromium alloys (AlCr), titanium-molybdenum alloys (TiMo), titanium-silicon alloys (TiSi), and tungsten carbide (WC).

[0107] Furthermore, when the target reactive film is an insulating coating, the sputtering power supply 28 may be, for example, a pulse power supply that outputs bipolar pulse power similar to the bias power supply 50, or a high frequency power supply that outputs radio frequency (RF) power. This prevents charge-up even if an insulating coating is deposited on the non-erosion region of the target 242, thereby stabilizing sputtering. Examples of insulating coatings include silicon carbonitride (SiCN) films, boron carbonitride (BCN) films, and aluminum oxynitride (AlON) films.

[0108] Additionally, when the target reactive film is an insulating coating, it is essential to provide an anode filament such as that disclosed in Japanese Patent No. 7507991. That is, when the target reactive film is an insulating coating, the surface of the ground shield 26 is covered with the insulating coating, which may prevent the ground shield 26 from functioning as an anode for inducing plasma 300. To address this issue, an anode filament such as that disclosed in Japanese Patent No. 7507991 is provided, which functions as an anode in place of the ground shield 26, thereby stabilizing the plasma 300 and ultimately stabilizing the film formation process for forming the target insulating coating.

[0109] Furthermore, in this embodiment, a pulse power supply is used as the bias power supply 50, but this is not limiting. For example, if the workpiece 100 is a conductive material and the target reaction film is also a conductive coating, a DC power supply may be used as the bias power supply 50. Note that even if the workpiece 100 is a conductive material, if the target reaction film is an insulating coating, it is appropriate to use a pulse power supply or a high-frequency power supply as the bias power supply 50. If the workpiece 100 is an insulating material, it is appropriate to use a high-frequency power supply as the bias power supply 50.

[0110] Furthermore, for example, multiple targets 242 may be provided, and more specifically, multiple magnetron sputtering cathodes 24 each including a target 242 may be provided. The targets 242 may be made of the same material. In this case, the deposition rate of the target reactive film is improved (faster). The targets 242 may also be made of different materials. In this case, a more multi-component reactive film can be formed. In either case, it is important to keep the inert gas flow rate Qi constant, the angle θ of the conductance valve 22 constant, the sputtering power Es constant, and the substrate bias voltage Vb constant, and then control the total gas flow rate Qa while maintaining the gas flow rate ratio Rq constant so that the pressure P in the vacuum chamber 12 is constant. In other words, it is important to individually control the flow rates Qr1, Qr2, ... of the reactive gases so that this is the case.

[0111] The present invention is not limited to application to the magnetron sputtering apparatus 10, but can also be applied to a film formation method using magnetron sputtering. [Explanation of symbols]

[0112] 10...Magnetron sputtering equipment 12 … Vacuum chamber 18... Vacuum pump 20... Opening and closing valve 22... Conductance valve 24...Magnetron cathode 26... Earth Shield 28 ... Sputter power supply 30... filament 32 ... Filament heating power supply 34 ... Arc discharge power supply 36... Current detector 38... Heating controller 50... Bias power supply 56... Gas inlet pipe 58,60,62,64 … branch pipe 58a, 60a, 62a, 64a ... Opening and closing valves 58b, 60b, 62b, 64b ... Mass flow controller 66 … Vacuum gauge 68... Total gas flow controller 70...Gas flow ratio controller 100...Processed object 242 … Target 300... Plasma

Claims

1. A film forming apparatus for forming a reaction film on a processing object by magnetron sputtering, a vacuum chamber that is at ground potential and that accommodates the workpiece; a magnetron sputtering cathode having a target that is a material for the reaction film and disposed inside the vacuum chamber such that a sputtering surface of the target faces the workpiece; an earth shield that is set to a ground potential and is provided so as to surround the outer periphery of the magnetron sputtering cathode while exposing the sputtering surface in order to limit the sputtering area of ​​the magnetron sputtering cathode to the sputtering surface; an exhaust means including a vacuum pump that exhausts the inside of the vacuum chamber through an exhaust port of the vacuum chamber, and a conductance valve that controls an effective exhaust speed at the exhaust port; an inert gas introducing means for introducing an inert gas into the vacuum chamber at a constant flow rate; a sputtering power supply means for supplying sputtering power to the earth shield and the magnetron sputtering cathode, with the earth shield serving as an anode and the magnetron sputtering cathode serving as a cathode, for discharging particles of the inert gas; a reactive gas introducing means for simultaneously introducing into the vacuum chamber a plurality of reactive gases that will be materials for the reactive film; a bias power supply means for supplying bias power having a constant predetermined component to the vacuum chamber and the workpiece, using the vacuum chamber as an anode and the workpiece as a cathode, for accelerating the particles of the inert gas, the particles of each of the plurality of types of reactive gases, and the sputtered particles sputtered from the sputtering surface of the target toward the workpiece; a cathode filament provided between the sputtering surface of the target and the workpiece; a heating power supply means for supplying heating power to the cathode filament to heat the cathode filament and cause thermions to be emitted from the cathode filament; an arc discharge power supply means for supplying arc discharge power to the earth shield and the cathode filament, with the earth shield serving as an anode and the cathode filament serving as a cathode, for accelerating the thermoelectrons toward the earth shield; a heating power control means for controlling the heating power so that a current component of the arc discharge power is constant while a voltage component of the arc discharge power is constant; and a reactive gas flow rate control means for controlling a total flow rate, which is the sum of the flow rates of the multiple reactive gases, into the vacuum chamber while keeping the ratio of the flow rates of the multiple reactive gases constant so that the pressure inside the vacuum chamber is constant while the sputtering power is kept constant and the effective exhaust speed is kept constant by the conductance valve.

2. The film forming apparatus according to claim 1 , wherein the mutual ratio can be set arbitrarily.

3. A film formation method for forming a reaction film on a processing object by magnetron sputtering, comprising: a workpiece placement step of placing the workpiece in a vacuum chamber that is set to ground potential and that has a magnetron sputtering cathode having a target that will be the material of the reaction film, so that the workpiece faces a sputtering surface of the target; an exhaust step of exhausting the inside of the vacuum chamber through an exhaust port of the vacuum chamber by a vacuum pump and controlling an effective exhaust speed at the exhaust port by a conductance valve; an inert gas introducing step of introducing an inert gas into the vacuum chamber at a constant flow rate; a sputtering power supply step of supplying sputtering power for discharging particles of the inert gas to the earth shield and the magnetron sputtering cathode, using an earth shield as an anode and the magnetron sputtering cathode as a cathode, the earth shield being set to a ground potential and provided so as to surround the outer periphery of the magnetron sputtering cathode while exposing the sputtering surface in order to limit the sputtering area of ​​the magnetron sputtering cathode to the sputtering surface; a reactive gas introduction step of simultaneously introducing into the vacuum chamber a plurality of reactive gases that will be materials for the reactive film; a bias power supply step of supplying bias power having a constant predetermined component to the vacuum chamber and the workpiece, using the vacuum chamber as an anode and the workpiece as a cathode, for accelerating the particles of the inert gas, the particles of each of the plurality of types of reactive gases, and the sputtered particles sputtered from the sputtering surface of the target toward the workpiece; a heating power supply step of supplying a heating power to a cathode filament provided between the sputtering surface of the target and the workpiece to heat the cathode filament and emit thermoelectrons from the cathode filament; an arc discharge power supply step of supplying arc discharge power to the earth shield and the cathode filament, with the earth shield serving as an anode and the cathode filament serving as a cathode, for accelerating the thermoelectrons toward the earth shield; a heating power control step of controlling the heating power so that a current component of the arc discharge power is constant while a voltage component of the arc discharge power is constant; and a reactive gas flow rate control step of controlling a total flow rate, which is the sum of the flow rates of the multiple types of reactive gases into the vacuum chamber, while keeping a constant ratio of the flow rates of the multiple types of reactive gases into the vacuum chamber, so that the pressure inside the vacuum chamber is constant, while the sputtering power is kept constant and the effective exhaust speed is kept constant by the conductance valve.

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