Film formation apparatus and film formation method using magnetron sputtering

Abstract

To form a reaction film with good reproductivity by stabilizing a sputtering speed in a film deposition device and a film deposition method by a magnetron sputtering method.SOLUTION: By a magnetron sputtering device 10 according to the present invention, discharging gas is supplied into a vacuum tank 12 at a constant flow rate Qd[Ar], and reactive gas is introduced into the vacuum tank 12 at a constant flow rate Qr. Furthermore, an angle θ of a conductance valve 22 is made constant, i.e, an effective exhaust speed at an exhaust port 14 of the vacuum tank 12 is made constant. Then, sputtering power Es is automatically controlled and arc-discharging power Ed is made constant, so that pressure P in the vacuum tank 12 is constant. Thereby, a sputtering speed is stabilized. Additionally, a substrate bias voltage Vb is made constant. As a result, reproductivity of a reaction film is improved, especially, reproductivity of film thickness and color tone is improved.SELECTED DRAWING: Figure 1

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 (compound film) on a processing object. [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 (magnetron cathode) having a target serving as a reactive film material is placed in a vacuum chamber at ground potential. A workpiece is also placed in the vacuum chamber facing the sputtering surface of the target. Furthermore, an earth shield is placed around the magnetron sputtering cathode, with only the sputtering surface of the target exposed. This earth shield is also at ground potential. The vacuum chamber is evacuated by a vacuum pump serving as an evacuation means, and an inert gas is introduced into the vacuum chamber. In this state, sputtering power is supplied to both the vacuum chamber (strictly speaking, the earth shield as the anode) and the magnetron sputtering cathode as the cathode. This causes discharge of inert gas particles, generating magnetron plasma that adheres to the sputtering surface of the target. The magnetron plasma discharges in the form of a high-voltage, low-current glow discharge. The magnetron plasma adheres to the surface of the target to be sputtered due to the action of the magnetic field formed by the magnet serving as magnetic field forming means provided in the magnetron sputtering cathode.

[0003] Particles of the inert gas in the magnetron plasma, particularly 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, a reactive gas, which is the material for the reactive film, is introduced into the vacuum chamber. The reactive gas particles are decomposed by the magnetron plasma. Then, bias power is supplied to the vacuum chamber, which serves as the anode, and the workpiece, which serves as the cathode. This accelerates the inert gas particles, reactive gas particles, and sputtered particles from the sputtering surface of the target toward the workpiece. In particular, the reactive gas particles and sputtered particles adhere to the surface of the workpiece and react with each other, forming a reactive film on the surface of the workpiece, composed of reactive gas particles and sputtered particles. Additionally, the bombardment effect of the inert gas particles on the surface of the workpiece increases the density of the reactive film.

[0004] Additionally, a cathode filament (filament) is provided between the target surface to be sputtered and the workpiece in the vacuum chamber. Heating power (thermionic emission power) is supplied to the cathode filament, heating it and emitting thermoelectrons. Furthermore, arc discharge power (discharge power) is supplied to both the vacuum chamber (strictly speaking, the earth shield as the anode and the cathode filament as the cathode). 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. The aforementioned magnetic field is formed around the cathode filament, and electrons accelerated from the cathode filament toward the earth shield undergo spiral motion (cycloidal 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. That is, in addition to the magnetron plasma due to glow discharge, an extremely high density plasma due to arc discharge is generated around the cathode filament, that is, between the sputtering surface of the target and the workpiece.

[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. This activates the sputtered particles, giving them energy at least higher than their ground state, and they are ionized particularly efficiently. Similarly, reactive gas particles are also more activated and ionized more efficiently. At the same time, inert gas 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, thereby increasing the hardness of the reaction film formed on the surface of the workpiece. Furthermore, the mutual bonding force between the sputtered particles and the reactive gas particles increases, resulting in a denser reaction film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-66483 Summary of the Invention [Problem to be solved by the invention]

[0007] Although not explicitly stated in Patent Document 1, the aforementioned exhaust means includes, in addition to the vacuum pump, a conductance valve installed in the pipe (exhaust path) connecting the exhaust port of the vacuum chamber and the intake port of the vacuum pump. This conductance valve has a plurality of elongated, plate-like blade members (louvers) arranged in parallel, for example, like blinds, and the angle θ of these blade members controls the effective exhaust speed at the exhaust port of the vacuum chamber. In the technology disclosed in Patent Document 1, the angle θ of the blade members of the conductance valve is automatically controlled (feedback controlled) so that the pressure P inside the vacuum chamber remains constant; in other words, the pressure P inside the vacuum chamber is used as a parameter.

[0008] However, the technology disclosed in Patent Document 1 has the problem that it is not possible to obtain reproducibility of the reaction film, particularly the color tone and film thickness of the reaction film. This is presumably due to the fact that the sputtering rate (the number of sputtered particles per unit time and unit area, which is sometimes called the "sputter evaporation rate," but which cannot be measured directly and is therefore commonly expressed as the mass sputtered per unit time (g / min)) of the sputtered surface of the target changes each time a film-forming process for forming a reaction film is performed, that is, for each batch, and as the batch is repeated.

[0009] For example, the color of the reaction film is affected by the composition of the reaction film. Taking a titanium nitride (TiN) film as an example of a reaction film, experience has shown that the color of a stoichiometric titanium nitride film is golden. However, if the composition deviates from the stoichiometric composition, for example, the more titanium atoms there are relative to the nitrogen atoms, the lighter the golden color tends to be. For example, when the titanium atoms are twice as many as the nitrogen atoms (TiN), the color becomes metallic (silver). Observing the sputtered surface of the target after the titanium nitride film deposition process reveals that the titanium nitride film adheres to the non-eroded regions of the sputtered surface, while the titanium nitride film does not adhere to the eroded regions. Furthermore, the appearance of the area near the boundary between the eroded and non-eroded regions varies from batch to batch; for example, it may be light gold or metallic. As mentioned above, magnetron plasma is generated in the vacuum chamber so as to adhere to the sputtering surface of the target. In addition, extremely high-density plasma is generated by arc discharge. Therefore, the space to which the sputtering surface is exposed is chemically highly active. Therefore, when the sputtering surface of the target is viewed microscopically, nitrogen penetrates near the boundary between the eroded and non-eroded regions, and this boundary is thought to be nitrided. Since the degree of nitridation varies from batch to batch, the sputtering rate varies from batch to batch, even over a relatively short period (short span). This changes the composition ratio of the titanium nitride film, which in turn leads to a loss of reproducibility in the color tone of the titanium nitride film.

[0010] Furthermore, when the sputtering rate changes, the reaction film formation rate (film formation rate) changes, and the film thickness of the reaction film changes. In particular, as batches are repeated (over a long period of time), the sputtering rate decreases, the reaction film formation rate decreases, and the film thickness of the reaction film tends to decrease. For example, if the target has a thickness of 8 mm and is used until the depth of the erosion region reaches 7 mm, the surface area of ​​the erosion region of the target at the end of use will be approximately 1.1 times larger than the surface area of ​​the erosion region of the target at the beginning of use. Therefore, when the sputtering power is constant, the power density of the sputtering power acting on the target at the end of use will be approximately 10% lower than the power density of the sputtering power acting on the target at the beginning of use. Therefore, as described above, as batches are repeated, the sputtering rate decreases, the reaction film formation rate decreases, and the film thickness of the reaction film tends to decrease.

[0011] Therefore, an object of the present invention is to provide a novel technology that can improve the reproducibility of reactive films by stabilizing the sputtering rate in a film formation apparatus and film formation method using reactive magnetron sputtering. [Means for solving the problem]

[0012] 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.

[0013] 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, and a sputtering power control means. Specifically, the vacuum chamber is grounded, i.e., at ground potential, and a workpiece is accommodated inside the vacuum chamber. The magnetron sputtering cathode has a target that will be the material for the reactive film, and is installed inside 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 exhaust speed at the exhaust port of the vacuum chamber. An inert gas introducing means introduces an inert gas into the vacuum chamber at a constant flow rate. A sputtering power supply means supplies sputtering power to the vacuum chamber (strictly speaking, the earth shield as the anode) and the magnetron sputtering cathode as the cathode. This causes the inert gas to discharge, generating magnetron plasma that adheres to the sputtering surface of the target. The magnetron plasma discharges in a high-voltage, low-current glow discharge manner. 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.

[0014] Particles of the inert gas in the magnetron plasma, particularly 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, a reactive gas introduction means introduces a reactive gas, which is the material for the reactive film, into the vacuum chamber at a constant flow rate. The reactive gas particles are decomposed by the magnetron plasma. The bias power supply 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, reactive gas particles, and sputtered particles from the sputtering surface of the target toward the workpiece at a constant acceleration. In particular, the reactive gas particles and sputtered particles adhere to the surface of the workpiece and react with each other, forming a reactive film composed of the reactive gas particles and sputtered particles on the surface of the workpiece. In addition, the density of the reaction film is improved by the bombardment action of the inert gas particles on the surface of the workpiece. Note that the predetermined component of the bias power is, for example, the average value or effective value of the bias voltage, which is the voltage component of the bias power.

[0015] 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 vacuum chamber (strictly speaking, 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, where they collide with inert gas particles, reactive gas particles, and sputter particles. The aforementioned magnetic field is formed around the cathode filament, and electrons accelerated from the cathode filament toward the earth shield undergo a spiral motion due to the effect of the magnetic field. This increases the frequency of collisions of the thermoelectrons with inert gas particles, reactive gas particles, and sputter particles, inducing a low-voltage, high-current arc discharge around the cathode filament. That is, in addition to the magnetron plasma due to glow discharge, an extremely high density plasma due to arc discharge is generated around the cathode filament, that is, between the sputtering surface of the target and the workpiece.

[0016] 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 ionizes them efficiently. Similarly, reactive gas particles are also more activated and ionized more efficiently. At the same time, inert gas particles are also more activated and ionized more efficiently. This improvement in ionization rate increases the amount of ions incident on the surface of the workpiece, thereby increasing the hardness of the reaction film formed on the surface of the workpiece. Furthermore, the mutual bonding force between the sputtered particles and the reactive gas particles increases, thereby densifying the reaction film.

[0017] Furthermore, the sputtering power control means controls the sputtering power so as to maintain a constant pressure inside the vacuum chamber, for example, by controlling the sputtering power via the sputtering power supply means. In this way, the effective pumping speed at the exhaust port of the vacuum chamber by the vacuum pump that evacuates the inside of the vacuum chamber is kept constant by the conductance valve, and the inert gas and reactive gas are each introduced into the vacuum chamber at a constant flow rate. Furthermore, the sputtering power is controlled so as to maintain a constant pressure inside the vacuum chamber, thereby maintaining a constant sputtering rate.

[0018] More specifically, the sputtering power control means controls the sputtering power so that the pressure inside the vacuum chamber is constant within a range lower than the pressure inside the vacuum chamber when an inert gas and a reactive gas are introduced into the vacuum chamber in parallel (simultaneously) with the sputtering power set to zero (not supplied) and the effective exhaust speed kept constant by the conductance valve, and higher than the pressure inside the vacuum chamber when only the inert gas is introduced into the vacuum chamber.

[0019] The arc discharge power supply means is, for example, a DC constant voltage power supply. In this case, it is desirable to further provide a heating power control means. The heating power control means controls the heating power so that the current component of the arc discharge power, i.e., the arc discharge current, is constant, and controls the heating power, for example, via the heating power supply means.

[0020] Furthermore, as the bias power, DC power, asymmetric bipolar pulse power, or high frequency power is selectively adopted depending on whether the object to be treated is a conductive (in other words, insulating) material, and also depending on whether the reaction film is a conductive (in other words, insulating) coating.

[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, and a sputtering power 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 evacuation 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. In the sputtering power supply step, sputtering power is supplied to the vacuum chamber (strictly speaking, the earth shield as the anode and the magnetron sputtering cathode as the cathode), with the vacuum chamber as the anode and the earth shield as the anode and the magnetron sputtering cathode as the cathode, respectively. This causes the inert gas to discharge, generating magnetron plasma that adheres to the sputtering surface of the target. The magnetron plasma discharge mode is a high-voltage, low-current glow discharge. 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, particularly 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, in the reactive gas introduction step, a reactive gas, which is the material for the reactive film, is introduced into the vacuum chamber at a constant flow rate. The reactive gas particles are decomposed by the magnetron plasma. Then, in the bias power supply step, a constant bias power with a predetermined composition 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 from the sputtering surface of the target toward the workpiece at a constant acceleration. In particular, the reactive gas particles and sputtered particles adhere to the surface of the workpiece and react with each other, forming a reactive film composed of the reactive gas particles and sputtered particles on the surface of the workpiece. In addition, the density of the reaction film is improved by the bombardment action of the inert gas particles on the surface of the workpiece. Note that the predetermined component of the bias power is, for example, the average value 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 both the vacuum chamber (strictly speaking, the earth shield as the anode and the cathode filament as the cathode), with the vacuum chamber serving as the anode and the earth shield as the cathode. The thermoelectrons emitted from the cathode filament are then accelerated toward the earth shield, where they collide with inert gas particles, reactive gas particles, and sputter particles. The aforementioned magnetic field is formed around the cathode filament, and the electrons accelerated from the cathode filament toward the earth shield undergo a spiral 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 filament. That is, in addition to the magnetron plasma due to glow discharge, an extremely high density plasma due to arc discharge is generated around the cathode filament, that is, between the sputtering surface of the target and the workpiece.

[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 ionizes them efficiently. Similarly, reactive gas particles are also more activated and ionized more efficiently. At the same time, inert gas particles are also more activated and ionized more efficiently. This improvement in ionization rate increases the amount of ions incident on the surface of the workpiece, thereby increasing the hardness of the reaction film formed on the surface of the workpiece. Furthermore, the mutual bonding force between the sputtered particles and the reactive gas particles increases, thereby densifying the reaction film.

[0025] Furthermore, in the sputtering power control step, the sputtering power is controlled so as to maintain a constant pressure inside the vacuum chamber. In this way, the effective pumping speed at the exhaust port of the vacuum chamber by the vacuum pump that evacuates the inside of the vacuum chamber is maintained constant by the conductance valve, and the inert gas and the reactive gas are introduced into the vacuum chamber at constant flow rates. Furthermore, the sputtering power is controlled so as to maintain a constant pressure inside the vacuum chamber, thereby maintaining a constant sputtering rate. [Effects of the Invention]

[0026] According to the present invention, the sputtering rate is stabilized, which improves the reproducibility of the reaction film, particularly the film thickness and color tone. [Brief explanation of the drawings]

[0027] [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 the results of an experiment using a conventional technique as a comparison with an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the relationship between the flow rate of nitrogen gas and the sputtering rate when it is assumed that a nitride film of stoichiometric composition is formed as a reaction film in one embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing experimental results in one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing another experimental result in an embodiment of the present invention. [Figure 9]FIG. 9 is a diagram showing still another experimental result in an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing still another experimental result in an embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing still another experimental result in an embodiment of the present invention. [Figure 12] FIG. 12 is a diagram showing a comparison of various control procedures in an embodiment of the present invention and a conventional technique for comparison. [Figure 13] FIG. 13 is a diagram showing a comparison of the reproducibility of titanium nitride films as reaction films formed by an embodiment of the present invention and a conventional technique as a comparison. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment of the present invention will be described in detail below.

[0029] 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 cylinder 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 exemplary and are determined appropriately depending on various factors, such as the size, shape, and number of workpieces 100, which will be described later. 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 walls are grounded, i.e., the potential of the walls is set to the ground potential, which is the reference potential.

[0030] 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 lower surface. The exhaust port 14 is connected to a vacuum pump 18 via exhaust piping 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 diffusion pump, a turbomolecular pump, a rotary pump, a mechanical booster pump, or the like, but is not limited to these.

[0031] Further, 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. In addition, a conductance valve 22 is provided midway along the exhaust pipe 16 for controlling the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 by the vacuum pump 18. Although not shown in detail, the conductance valve 22 has a plurality of elongated plate-like blade members arranged in parallel like blinds, and controls the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 by the angle θ of these blade members. This configuration of the conductance valve 22 is one example, and is not limiting.

[0032] 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, 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, as one magnetic pole, an N-pole 246a, which is a roughly rectangular frame-like pole and is provided along the periphery of the target 242 while being in close contact with the back surface of the target 242, and an S-pole 246b, which is a long, slender protrusion-like pole and is provided inside the N-pole 246a, so as to be in close contact with the back surface of the target 242 and extend 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-like 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.

[0033] 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.

[0034] More specifically, as described above, the earth shield 26 is disposed around the outer periphery of the magnetron sputtering cathode 24, with the sputtering surface of the target 242 of the magnetron sputtering cathode 24 exposed. The distance between the outer surface of the magnetron sputtering cathode 24 and the inner surface of the earth shield 26 is, for example, approximately 2 mm, which is quite close. The earth shield 26 is substantially flush with the sputtering surface of the target 242 and has a 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 portion being, for example, 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 ensure that its own potential is at ground potential.

[0035] 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.

[0036] 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.

[0037] 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).

[0038] 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 FIG. 4(b), 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 suitably set to approximately 5 mm to 50 mm, for example, 25 mm. The length of the cathode filament 30 is equal to or longer than the length of the target 242, and more precisely, equal to or longer 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 or both ends of the cathode filament 30 as tensioning means for applying an appropriate tension to the cathode filament 30 and maintaining the cathode filament 30 in a straight state.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 (feedback controlled) using the arc discharge current Id as a parameter.

[0043] 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.

[0044] 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 rotates, the workpiece 100 also rotates in the same direction, or in other words, spins on its own axis. The revolution path diameter (PCD) of the workpiece 100 is, for example, approximately 600 mm. The revolution speed of the workpiece 100 (the rotation speed of the revolving 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. 1 and 2 show an example in which the number of workpieces 100 (holders 40 and gear mechanisms 42) is 12, but 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.

[0045] 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.

[0046] 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.

[0047] 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 and 60, two in this example, are connected to the gas inlet pipe 56.

[0048] One branch pipe 58 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 Qd of the inert gas flowing through the branch pipe 58. The branch pipe 58 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 gas.

[0049] The other branch pipe 60 is a pipe for introducing a reactive gas into the vacuum chamber 12 and is supplied with the reactive gas from a supply source (not shown). This branch pipe 60 for introducing the reactive gas is also provided with an on-off valve 60a as an on-off means for opening and closing the branch pipe 60 and a mass flow controller 60b as a flow rate control means for controlling the flow rate Qr of the reactive gas flowing through the branch pipe 60. The branch pipe 60 including the on-off valve 60a and the mass flow controller 60b, in cooperation with the gas inlet pipe 56, constitutes an example of a reactive gas introduction means. An appropriate gas is used as the reactive gas depending on the type of reactive film to be formed. For example, when a nitride film is to be formed as the reactive film, nitrogen (N) gas is used as the reactive gas. When a carbonized film is to be formed as the reactive film, a hydrocarbon gas such as acetylene (CH) is used as the reactive gas. When an oxide film is to be formed as the reactive film, oxygen (O) gas is used as the reactive gas.

[0050] Additionally, a pressure gauge 62 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) 62a of the pressure gauge 62 is disposed. The pressure gauge 62 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 62a is disposed. The measured value of the pressure P by the pressure gauge 62 is provided to a sputtering power controller 64, which is an example of a sputtering power control means, located outside the vacuum chamber 12. Note that a diaphragm vacuum gauge capable of measuring absolute pressure is used as the pressure gauge 62. The position where the gauge portion 62a 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. The main body of the pressure gauge 62 is provided outside the vacuum chamber 12.

[0051] The sputtering power controller 64 controls the sputtering power supply 28 so that the measured value of the pressure P by the pressure gauge 62 becomes constant, that is, so that the pressure P becomes constant, and more specifically, controls the sputtering power Es via the sputtering power supply 28. That is, the sputtering power Es is automatically controlled (feedback controlled) using the pressure P inside the vacuum chamber 12 as a parameter. The sputtering power controller 64 may be incorporated into the sputtering power supply 28, for example.

[0052] 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 revolution 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.

[0053] The magnetron sputtering apparatus 10 configured as described above can form various reactive films on the surface of the workpiece 100. For example, the case of forming a titanium nitride film as the reactive film will be described. In this case, titanium with a purity of 3N or higher is used as the target 242. In addition, nitrogen gas with a purity of 5N or higher is used as the reactive gas.

[0054] 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 about 150°C. As a result, impurity gases contained in workpiece 100 are discharged, and so-called degassing is performed.

[0055] After this degassing process is performed for a predetermined time (for example, about 30 minutes to 1 hour), the supply of heater heating power to the carbon heater 52 is stopped, and then, the discharge cleaning process is performed. In this discharge cleaning process, 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 is introduced into the vacuum chamber 12. The accelerated thermoelectrons then collide with argon gas particles, and the argon gas particles are ionized by the impact, generating plasma 300.

[0056] Here, a magnetic field is formed by the permanent magnet 246 described above in the vicinity of the sputtering surface of the target 242, including the periphery of the cathode filament 30, and 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 gas particles increases, thereby increasing the density of the plasma 300. The discharge mode of such plasma 300 is a low-voltage, high-current arc discharge. Note that an arc discharge can be induced, for example, even when the pressure P in the vacuum chamber 12 is in the range of 0.01 Pa to 1 Pa, that is, even under conditions where the pressure P is relatively low.

[0057] While the plasma 300 is being generated by this arc discharge, a 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. Then, argon particles in the plasma 300, particularly argon ions, are actively incident on the surface of the workpiece 100. This impact removes impurities from the surface of the workpiece 100, thereby performing a so-called discharge cleaning process. Note that, since the workpiece 100 rotates and revolves as described above, the discharge cleaning process is performed while the workpiece 100 is exposed to the plasma 300 during this rotation and revolution process.

[0058] After this discharge cleaning process is performed for a predetermined time (e.g., about 30 minutes), a film formation process is performed to form a titanium nitride film. To this end, sputtering power Es is supplied to magnetron sputtering cathode 24. Specifically, sputtering power Es is supplied to both earth shield 26, which serves as the anode, and magnetron sputtering cathode 24, which serves as the cathode. Argon ions in plasma 300 then collide with the sputtering surface of target 242 of magnetron sputtering cathode 24, knocking titanium particles off the sputtering surface of target 242, i.e., sputtering. The sputtering region, which is the area to be sputtered, is limited to the sputtering surface of target 242; in other words, the earth shield 26 is positioned to limit this. Furthermore, nitrogen gas is introduced into vacuum chamber 12 as a reactive gas. The nitrogen gas particles are decomposed by plasma 300.

[0059] As described above, titanium particles as sputtered particles sputtered from the sputtering surface of the target 242 are accelerated toward the workpiece 100 to which the substrate bias power Eb is supplied. At the same time, particles of decomposed nitrogen gas are also accelerated toward the workpiece 100. These titanium particles and nitrogen particles adhere to the surface of the workpiece 100 and react with each other, forming a titanium nitride film, which is a reaction film composed of titanium particles and nitrogen particles, on the surface of the workpiece 100. Furthermore, argon ions in the plasma 300 are also accelerated toward the workpiece 100. The bombardment action of these argon ions on the surface of the workpiece 100 improves the density of the titanium nitride film formed on the surface of the workpiece 100.

[0060] In this film formation process, the supply of sputtering power Es also causes argon gas particles to discharge, inducing magnetron plasma due to high-voltage, low-current glow discharge. That is, plasma 300 includes (combines) magnetron plasma due to glow discharge in addition to the arc discharge described above. This magnetron plasma due to glow discharge is generated so that it adheres to the sputtering surface of target 242 due to the action of the magnetic field created by permanent magnet 246 described above.

[0061] Then, the titanium particles, nitrogen particles, and argon particles pass through the space of the extremely high-density plasma 300 on their way toward the workpiece 100. This causes the titanium particles, nitrogen particles, and argon particles to be more activated and more efficiently ionized. This improvement in ionization rate increases the number of ions incident on the surface of the workpiece 100, thereby increasing the hardness of the titanium nitride film formed on the surface of the workpiece 100. At the same time, the mutual bonding force between the titanium particles and the nitrogen particles increases, resulting in a densified titanium nitride film.

[0062] In this film formation process, similarly to the discharge cleaning process described above, the workpiece 100 is subjected to the film formation process while it is exposed to the plasma 300 during its rotation and revolution. The pressure P in the vacuum chamber 12 during the film formation process is controlled within a range of 0.1 Pa to 1 Pa, for example.

[0063] 4, focusing on the sputtering surface of the target 242, the density of the plasma 300 is higher in a region near the sputtering surface where the plasma 300 is generated, the region following the gap 246c of the permanent magnets 246. Therefore, the region of the sputtering surface of the target 242 where the density of the plasma 300 is higher, that is, the region following the gap 246c of the permanent magnets 246, is sputtered more efficiently (intensively). As a result, sputtering marks in the shape of a roughly rectangular loop (or an oval loop) following the gap 246c of the permanent magnets 246 appear on the sputtering surface of the target 242, that is, erosion regions 242a are formed.

[0064] After this film formation process is performed for a predetermined time (the time required to form a titanium nitride film of a predetermined thickness), the introduction of argon gas and nitrogen gas into the vacuum chamber 12 is 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. A certain cooling period is then allowed while the pressure P within the vacuum chamber 12 is gradually returned to near atmospheric pressure. Thereafter, the driving of the motor 48 is stopped, and the rotation and revolution of the workpiece 100 are stopped. The vacuum chamber 12 is then opened to the outside, and the workpiece 100 is removed from the vacuum chamber 12. This completes the series of processes, including the film formation process for forming the titanium nitride film.

[0065] In the explanation of this series of processes, particularly in the explanation of the film formation process, no particular reference has been made to the sputtering power controller 64, but as mentioned above, the sputtering power controller 64 controls the sputtering power Es so that the pressure P inside the vacuum chamber 12 is constant. Furthermore, in the film formation process, the angle θ (of the blade member) of the conductance valve 22 is kept constant, thereby keeping the effective exhaust speed at the exhaust port 14 of the vacuum chamber 12 constant. The actions and effects of performing the film formation process in this manner will be explained in detail later.

[0066] In contrast, when a film formation process is performed using the conventional technology disclosed in, for example, the aforementioned Patent Document 1, the sputtering power Es is kept constant, and the angle θ of the conductance valve is automatically controlled so that the pressure P in the vacuum chamber is kept constant.

[0067] Specifically, for example, when a film formation process for forming a titanium nitride film is performed using conventional technology, the flow rate Qd of argon gas as an inert gas (hereinafter referred to as "Q[Ar]") is kept constant, and the flow rate Qr of nitrogen gas as a reactive gas (hereinafter referred to as "Q[N2]") is kept constant. Then, the angle θ of the conductance valve is automatically controlled so that the pressure P in the vacuum chamber is kept constant. In addition, the arc discharge power Ed, the sputtering power Es, and the substrate bias voltage Vb (average value) are kept constant.

[0068] An experiment was conducted to determine the properties of a titanium nitride film obtained when a film formation process for forming a titanium nitride film using such conventional technology. The results are shown in Figure 5. Figure 5(a) shows the film formation conditions used in this experiment, Figure 5(b) shows the measurement results for the thickness and color of the titanium nitride film formed by the film formation process, and Figure 5(c) shows a photograph of the appearance of the titanium nitride film.

[0069] As shown in Figure 5(a), in this experiment, the argon gas flow rate Q [Ar] was set to 100 mL / min (constant), and the nitrogen gas flow rate Q [N2] was set to 40 mL / min (constant). The pressure P in the vacuum chamber was set to 0.3 Pa (constant), and the angle θ of the conductance valve was automatically controlled to achieve this. Furthermore, the arc discharge power Ed was set to 700 W (constant). Specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant). The cathode power Ec was automatically controlled so that the arc discharge current Id, which is the current component of the arc discharge power Ed, was set to 14 A (constant). In addition, the sputtering power Es was set to 8 kW (constant), and the substrate bias voltage Vb (average value) was set to -100 V (constant). The film formation process under these conditions was performed twice (two batches) over a period T (film formation time) of 80 minutes.

[0070] As shown in Figure 5(b), the titanium nitride film formed by the first (first batch) deposition process, i.e., sample 1, had a thickness of 0.75 μm. In contrast, the titanium nitride film formed by the second (second batch) deposition process, i.e., sample 2, had a thickness of 0.96 μm. That is, the difference in thickness between sample 1 and sample 2 was 0.21 μm. This difference in thickness of 0.21 μm is relatively large compared to the respective thicknesses of sample 1 and sample 2, indicating that good reproducibility of the film thicknesses cannot be obtained. The film thickness was measured by measuring the step height using a contact-type surface roughness meter. Silicon (Si) wafers were used as the substrates for film thickness measurement.

[0071] On the other hand, when we look at the color tone, the L * ,a * and b * The values ​​of L of sample 2 were 56.35, 8.74 and 32.61, respectively. * ,a * and b * were 60.56, 2.97 and 16.91, respectively. That is, the difference ΔL * ,Δa* and Δb * were 4.21, 5.77, and 15.70, respectively. * ,Δa * and Δb * The values ​​of L for sample 1 and sample 2 are * ,a * and b * In comparison with the values ​​of , all of them are relatively large, which means that good reproducibility of color tone cannot be obtained. Color tone measurements were performed using a color difference meter (CR-400) manufactured by Konica Minolta, Inc. A mirror-finished SUS304 plate (30 mm x 30 mm x 1 mm) was used as the object to be processed for color tone measurement.

[0072] As shown in Figure 5(c), it is clear from their appearance that Sample 1 and Sample 2 have completely different color tones. For example, Sample 1 has the gold color characteristic of titanium nitride films, while Sample 2 has a lighter gold color, a whitish gold color. In the photograph of the appearance shown in Figure 5(c), Sample 1 and Sample 2 have been covered with tracing paper to reduce their gloss and make them easier to see. A ruler has also been added to allow for an intuitive understanding of the sizes of Sample 1 and Sample 2.

[0073] As is clear from these experimental results, the conventional technology does not provide reproducible thickness and color of the titanium nitride film. The reason for this is presumably that, as mentioned above, the sputtering rate of the sputtering surface of the target changes each time a film formation process for forming a titanium nitride film is performed, in other words, for each batch, and as the batch is repeated.

[0074] Therefore, in this embodiment, when a film formation process for forming a titanium nitride film is performed, the flow rate Q [Ar] of argon gas as an inert gas and the flow rate Q [N2] of nitrogen gas as a reactive gas are kept constant. 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 automatically controlled so that the pressure P inside the vacuum chamber 12 is kept constant. At the same time, the arc discharge power Ed is kept constant. By performing the film formation process in this manner, the sputtering rate is stabilized. Furthermore, the substrate bias voltage Vb (average value) is kept constant. This improves the reproducibility of the film thickness and color tone of the titanium nitride film. This will be explained in detail below.

[0075] First, the composition (formation mechanism) of the titanium nitride film will be considered stoichiometrically. That is, the chemical reaction formula when titanium particles as sputtered particles sputtered from the target 242 (sputtering surface) and nitrogen gas particles introduced into the vacuum chamber 12 react with each other to form a titanium nitride film is expressed by the following formula 1.

[0076] 《Formula 1》 2Ti+N2→2TiN

[0077] Based on this formula 1, if we assume that all of the nitrogen gas particles introduced into the vacuum chamber 12 react with titanium particles, then for this to happen, the amount of titanium particles that corresponds to the flow rate Q[N2] of the nitrogen gas must be sputtered from the target 242. This relationship can be expressed graphically as shown in Figure 6.

[0078] In FIG. 6, for example, when the flow rate Q[N2] of the nitrogen gas is 70 mL / min, the number of particles of the nitrogen gas introduced into the vacuum chamber 12, for example, the number of nitrogen molecules, is 1.88×10 21 Therefore, the number of nitrogen atoms is 3.76 × 10 21 Therefore, the number of titanium atoms required to react with nitrogen atoms is 3.76 × 10 21This results in a sputtering rate of approximately 0.30 g / min. Figure 6 shows this relationship. According to this relationship, it is estimated that by sputtering titanium particles from target 242 in an amount commensurate with the nitrogen gas flow rate Q [N2], or in other words, by supplying sputtering power Es to target 242 to achieve this, the formation rate of the titanium nitride film can be controlled; in other words, the sputtering rate can be controlled.

[0079] In sputtering apparatuses, including the magnetron sputtering apparatus 10 according to the present embodiment, an inert gas such as argon gas is generally used as the sputtering gas for sputtering the target 242. When forming a reactive film such as a titanium nitride film as a coating, i.e., when forming the reactive film by reactive magnetron sputtering, a reactive gas is introduced into the vacuum chamber 12 in addition to the inert gas. It is not preferable to form a reactive film using only a reactive gas without an inert gas. Because reactive gas particles are lighter than inert gas particles such as argon gas, attempting to sputter the target 242 using such light reactive gas particles results in a low sputtering rate, i.e., a low film formation rate, resulting in a lack of productivity (practicality). Furthermore, when sputtering the target 242 using reactive gas particles, the sputtered surface of the target 242 is altered (e.g., nitrided), further reducing the sputtering rate. For these reasons, when forming a reactive film, an inert gas is introduced into the vacuum chamber 12 in addition to the reactive gas. In this regard, the flow rate ratio, which is the ratio between the flow rate Qd of the inert gas and the flow rate Qr of the reactive gas, is also extremely important.

[0080] Next, an experiment was conducted to confirm the relationship between the angle θ of the conductance valve 22 and the pressure P within the vacuum chamber 12 when only argon gas as an inert gas or argon gas and nitrogen gas as a reactive gas were introduced into the vacuum chamber 12 in a state where sputtering was not performed (strictly speaking, the sputtering power Es, cathode power Ec, arc discharge power Ed, and substrate bias power Eb (substrate bias voltage Vb) were all set to zero (not supplied)). The results are shown in Figure 7. In Figure 7, the thick dashed line following the open circles indicates the relationship when only argon gas was introduced into the vacuum chamber 12 at a constant flow rate Q[Ar] of 100 mL / min. In Figure 7, the thick solid line following the filled circles indicates the relationship when argon gas was introduced into the vacuum chamber 12 at a constant flow rate Q[Ar] of 100 mL / min and nitrogen gas was introduced into the vacuum chamber 12 at a constant flow rate Q[N2] of 40 mL / min. Furthermore, the smaller the angle θ of the conductance valve 22, the greater the conductance, and when the angle θ is 0 degrees, the conductance valve 22 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.

[0081] 7, when only argon gas is introduced into vacuum chamber 12, the angle θ of conductance valve 22 and the pressure P inside vacuum chamber 12 are proportional to each other. Similarly, when argon gas and nitrogen gas are introduced into vacuum chamber 12 in parallel, the angle θ of conductance valve 22 and the pressure P inside vacuum chamber 12 are also proportional to each other. Furthermore, if the angle θ of conductance valve 22 is the same, the pressure P inside vacuum chamber 12 is about 0.09 Pa higher when argon gas and nitrogen gas are introduced into vacuum chamber 12 in parallel than when only argon gas is introduced into vacuum chamber 12. This pressure difference ΔP of 0.09 Pa corresponds to the flow rate Q[N2] of nitrogen gas. This can be understood from the fact that the flow rate Q (=Q[Ar] or Q[Ar]+Q[N2]) of the gas introduced into the vacuum chamber 12, the pressure P inside the vacuum chamber 12, and the effective pumping speed S, which is determined by the angle θ of the conductance valve 22, have a relationship expressed by the following equation 2.

[0082] 《Formula 2》 Q=P×S

[0083] Based on the relationship shown in Figure 7, argon gas and nitrogen gas are introduced into the vacuum chamber 12 in parallel, and sputtering is performed with the angle θ of the conductance valve 22 fixed at a certain value. Specifically, the sputtering power Es, cathode power Ec, arc discharge power Ed, and substrate bias power Eb (substrate bias voltage Vb) are supplied. Then, titanium particles, which are sputtered particles, react with nitrogen gas particles (gettering). This reduces the number of nitrogen gas particles present in the vacuum chamber 12, and the pressure P within the vacuum chamber 12 decreases. The degree of this decrease in pressure P within the vacuum chamber 12 depends on the amount of titanium particles, in other words, the sputtering power Es. In other words, the higher the sputtering power Es, the more titanium particles react with nitrogen gas particles, and therefore the greater the decrease in pressure P within the vacuum chamber 12. Conversely, the smaller the sputtering power Es, the fewer titanium particles react with nitrogen gas particles, and therefore the smaller the degree of decrease in pressure P inside vacuum chamber 12. Even if all of the nitrogen gas particles present in vacuum chamber 12 react with titanium particles, argon gas (basically) does not react with titanium particles, so the pressure P inside vacuum chamber 12 is maintained at a value corresponding to the argon gas flow rate Q [Ar], and this value becomes the lower limit of the pressure P inside vacuum chamber 12.

[0084] From these physical and chemical phenomena, it is presumed that, during the film formation process for forming a titanium nitride film, argon gas is introduced into vacuum chamber 12 at a constant flow rate Q [Ar], nitrogen gas is introduced at a constant flow rate Q [N2], and the angle θ of conductance valve 22 is fixed at a constant value, and the sputtering power Es is automatically controlled so that the pressure P in vacuum chamber 12 is constant, thereby stabilizing the sputtering rate. At this time, the sputtering power Es, cathode power Ec, arc discharge power Ed, and substrate bias power Eb are all set to zero, and the pressure P in vacuum chamber 12 is controlled to be constant within a range lower than the pressure P in vacuum chamber 12 when argon gas and nitrogen gas are introduced into vacuum chamber 12 in parallel, but equal to or higher than the pressure P in vacuum chamber 12 when only argon gas is introduced into vacuum chamber 12, with the angle θ of conductance valve 22 fixed at a constant value. At the same time, the arc discharge power Ed is kept constant. By stabilizing the sputtering rate in this way and then keeping the substrate bias voltage Vb (average value) constant, it is possible to form a titanium nitride film with good reproducibility, and it is estimated that good reproducibility can be obtained, particularly with regard to the thickness and color tone of the titanium nitride film.

[0085] In light of this, in this embodiment, the sputtering power Es is automatically controlled so that the pressure P in the vacuum chamber 12 is constant, as described above. Referring again to FIG. 7 , for example, assume that argon gas is introduced into the vacuum chamber 12 at a constant flow rate Q[Ar] of 100 mL / min, and nitrogen gas is introduced into the vacuum chamber 12 at a constant flow rate Q[N2] of 40 mL / min, and that under these conditions, the sputtering power Es is automatically controlled so that the pressure P in the vacuum chamber 12 is 0.3 Pa. In this case, the shaded area in FIG. 7 corresponds to the control range (width) of the sputtering power Es. That is, the angle θ of the conductance valve 22 changes the sputtering power Es required to maintain the pressure P in the vacuum chamber 12 at 0.3 Pa, which in turn changes the amount of titanium particles sputtered from the target 242. In other words, this changes the amount of nitrogen gas particles that react with the titanium particles.

[0086] 7, when the angle θ of the conductance valve 22 is 57 degrees, the lower limit of the pressure P in the vacuum chamber 12 (the value indicated by the thick dashed line) is approximately equivalent to the target value (set value) of 0.3 Pa for the pressure P in the vacuum chamber 12. Therefore, the sputtering power Es for setting the pressure P in the vacuum chamber 12 to the target value of 0.3 Pa is maximized within the control range, and it is expected that a titanium nitride film can be formed most efficiently. When the angle θ of the conductance valve 22 is 48 degrees or less, the upper limit of the pressure P in the vacuum chamber 12 (the value indicated by the thick solid line) is equal to or less than 0.3 Pa, which is the target value of the pressure P in the vacuum chamber 12. Therefore, it is not necessary to supply the sputtering power Es to set the pressure P in the vacuum chamber 12 to the target value of 0.3 Pa. Therefore, titanium particles are not sputtered from the target 242, and a titanium nitride film is not formed.

[0087] If the pressure P in the vacuum chamber 12 is set to a value other than 0.3 Pa, for example, if the pressure P in the vacuum chamber 12 is set to a value higher than 0.3 Pa, the shaded area in FIG. 7 will shift overall to the upper right. On the other hand, if the pressure P in the vacuum chamber 12 is set to a value lower than 0.3 Pa, the shaded area in FIG. 7 will shift overall to the lower left. In any case, as described above, it is important that the sputtering power Es is automatically controlled so that the pressure P in the vacuum chamber 12 is constant within a range lower than the pressure P in the vacuum chamber 12 when argon gas and nitrogen gas are introduced into the vacuum chamber 12 in parallel, with the sputtering power Es, cathode power Ec, arc discharge power Ed, and substrate bias power Eb all set to zero and the angle θ of the conductance valve 22 fixed at a constant value, but not lower than the pressure P in the vacuum chamber 12 when only argon gas is introduced into the vacuum chamber 12.

[0088] Furthermore, in this example, an experiment was conducted to confirm the relationship between the angle θ of the conductance valve 22 and the formation rate of the titanium nitride film. The results are shown in Figure 8. Figure 8(a) shows the film formation conditions used in this experiment, and Figure 8(b) shows the relationship between the angle θ of the conductance valve 22 and the formation rate of the titanium nitride film obtained from this experiment.

[0089] Specifically, as shown in FIG. 8(a), in this experiment, the argon gas flow rate Q [Ar] was set to 100 mL / min (constant), and the nitrogen gas flow rate Q [N2] was set to 40 mL / min (constant). The angle θ of the conductance valve 22 was set from 52 to 57 degrees in 1-degree increments. At each angle θ, the sputtering power Es was automatically controlled so that the pressure P in the vacuum chamber 12 was maintained at 0.3 Pa (constant). Furthermore, the arc discharge power Ed was set to 700 W (constant). Specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant). The cathode power Ec was automatically controlled so that the arc discharge current Id, which is the current component of the arc discharge power Ed, was maintained at 14 A (constant). The substrate bias voltage Vb (average value) was set to -100 V (constant), and the deposition time T was 80 minutes. The sputtering power Es varies depending on the angle θ of the conductance valve 22. When the sputtering power Es was observed, for example, the sputtering power Es was approximately 5.3 kW on average when the angle θ of the conductance valve 22 was 52 degrees, and the sputtering power Es was approximately 8.7 kW on average when the angle θ of the conductance valve 22 was 57 degrees.

[0090] As shown in Figure 8(b), this experiment confirmed that the angle θ of the conductance valve 22 and the titanium nitride film formation rate are proportional to each other. When these experimental results are considered in relation to the experimental results shown in Figure 7, for example, the amount of nitrogen gas particles capable of reacting with titanium particles is maximized when the angle θ of the conductance valve 22 is 57°. This means that the amount of nitrogen gas particles required to react with titanium particles is proportional to the pressure difference ΔP of 0.09 Pa. This increases the sputtering power Es, but also results in a correspondingly high titanium nitride film formation rate. Furthermore, the experimental results shown in Figure 8(b) suggest that when the angle θ of the conductance valve 22 is 48°, the titanium nitride film formation rate is essentially zero, meaning that no titanium nitride film is formed. This is consistent with the experimental results shown in Figure 7, which indicate that a titanium nitride film cannot be formed when the angle θ of the conductance valve 22 is less than 48°.

[0091] Additionally, in this example, an experiment was conducted to confirm the relationship between the nitrogen gas flow rate Q [N2] and the titanium nitride film formation rate. The results are shown in Figure 9. Figure 9(a) shows the film formation conditions used in this experiment. Figure 9(b) shows the relationship between the nitrogen gas flow rate Q [N2] and the titanium nitride film formation rate obtained from this experiment.

[0092] Specifically, as shown in FIG. 9(a), in this experiment, the flow rate Q [Ar] of argon gas was set to 100 mL / min (constant). The angle θ of the conductance valve 22 was set to 57 degrees. The flow rate Q [N2] of nitrogen gas was then set from 10 mL / min (constant) to 40 mL / min (constant) in 10 mL / min increments, and was also set to 45 mL / min (constant). With each flow rate Q [N2] set, the sputtering power Es was automatically controlled so that the pressure P in the vacuum chamber 12 was 0.3 Pa (constant). Furthermore, the arc discharge power Ed was set to 700 W (constant). Specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant). The cathode power Ec was automatically controlled so that the arc discharge current Id, which is the current component of the arc discharge power Ed, was 14 A (constant). In addition, the substrate bias voltage Vb (average value) was set to -100 V (constant), and the film formation time T was set to 80 minutes. The sputtering power Es varied depending on the nitrogen gas flow rate Q [N2]. When this sputtering power Es was observed, for example, when the nitrogen gas flow rate Q [N2] was 10 mL / min, the sputtering power Es was approximately 2 kW on average, and when the nitrogen gas flow rate Q [N2] was 45 mL / min, the sputtering power Es was approximately 10 kW on average.

[0093] As a result of this experiment, it was confirmed that the nitrogen gas flow rate Q[N2] and the titanium nitride film formation rate are proportional to each other, as shown in Figure 9(b). In other words, the higher the nitrogen gas flow rate Q[N2], the more titanium particles must be reacted with the nitrogen gas particles, and the greater the sputtering power Es, which leads to a corresponding increase in the titanium nitride film formation rate.

[0094] Taking all of this into consideration, as mentioned above, during the film formation process for forming a titanium nitride film, the flow rate Q [Ar] of the argon gas as the discharge gas and the flow rate Q [N2] of the nitrogen gas as the reactive gas are kept constant, and the angle θ of the conductance valve 22 is kept constant. The sputtering power Es is automatically controlled to maintain a constant pressure P within the vacuum chamber 12, thereby stabilizing the sputtering rate. It is essential to maintain a constant arc discharge power Ed. Furthermore, maintaining a constant substrate bias voltage Vb (average value) is essential to form a titanium nitride film with good reproducibility, particularly with regard to the thickness and color of the titanium nitride film. Naturally, it is also essential to maintain a constant film formation time T.

[0095] To verify this, an experiment was conducted in this example to determine whether a titanium nitride film could be actually formed and whether its reproducibility, particularly in terms of color tone and film thickness, could be achieved. The results are shown in Figures 10 and 11. Figure 10(a) shows the film formation conditions used in this experiment, and Figure 10(b) shows the results of measuring the color tone of the titanium nitride film formed in this experiment. Finally, Figure 11 shows the results of measuring the film thickness of the titanium nitride film formed in this experiment.

[0096] Specifically, as shown in FIG. 10(a), in this experiment, the argon gas flow rate Q [Ar] was set to 100 mL / min (constant), and the nitrogen gas flow rate Q [N2] was set to 40 mL / min (constant). The angle θ of the conductance valve 22 was set to 57 degrees, and the sputtering power Es was automatically controlled so that the pressure P in the vacuum chamber 12 was 0.3 Pa (constant). Furthermore, the arc discharge power Ed was set to 1000 W (constant). Specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant). The cathode power Ec was automatically controlled so that the arc discharge current Id, which is the current component of the arc discharge power Ed, was 20 A (constant). The substrate bias voltage Vb (average value) was set to -100 V (constant), and the film formation time T was 80 minutes. The film formation process under these conditions was performed 11 times (11 batches).

[0097] For each titanium nitride film formed by these 11 film formation processes (batches), the L * ,a * and b * As shown in Figure 10(b), the L * ,a * and b * Each difference (variation) ΔL * ,Δa * and Δb * The values ​​were 1.77, 1.54, and 1.91, which were all less than 2. * ,Δa * and Δb * The value of each difference ΔL * ,Δa * and Δb *, which is much smaller than the value of . In other words, it was confirmed that good reproducibility of color tone could be obtained according to this example. Furthermore, although not shown in the figures, it was also confirmed from appearance that the color tone of each titanium nitride film was the gold color characteristic of the titanium nitride film. Note that color tone measurements were performed using a color difference meter (CR-400) manufactured by Konica Minolta, Inc., as in the experiment on color tone in the prior art described above. A mirror-finished SUS304 plate (30 mm x 30 mm x 1 mm) was used as the processing object 100 for color tone measurement.

[0098] On the other hand, when we focused on the film thickness, we measured the thickness of each titanium nitride film formed by 11 film formation processes, and as shown in Figure 11, the difference (variation) in film thickness was 0.05 μm. This film thickness difference of 0.05 μm is much smaller than the film thickness difference obtained by the prior art described above. Furthermore, when this film thickness difference of 0.05 μm is expressed as a ratio to the average film thickness of each titanium nitride film formed by 11 film formation processes, it is ±3.6%, which is a level that is fully practical. In other words, this example confirmed that good film thickness reproducibility could be obtained.

[0099] FIG. 12 shows a list of the control procedures for performing the film forming process to form a titanium nitride film according to this embodiment and the control procedures according to the above-mentioned prior art.

[0100] 12, when a film formation process for forming a titanium nitride film is performed using the above-mentioned conventional technology, the flow rate Q [Ar] of argon gas as a discharge gas and the flow rate Q [N2] of nitrogen gas as a reactive gas are kept constant. The angle θ of the conductance valve is automatically controlled so that the pressure P in the vacuum chamber is kept constant. Additionally, the arc discharge power Ed, the sputtering power Es, and the substrate bias voltage Vb (average value) are kept constant. The film formation time T is kept constant.

[0101] In contrast, when a film formation process for forming a titanium nitride film is performed according to this embodiment, the flow rate Q [Ar] of argon gas as a discharge gas is kept constant, and the flow rate Q [N2] of nitrogen gas as a reactive gas is kept constant. The angle θ of the conductance valve 22 is kept constant. Furthermore, the sputtering power Es is automatically controlled so that the pressure P in the vacuum chamber 12 is kept constant. Additionally, the arc discharge power Ed is kept constant, and the substrate bias voltage Vb (average value) is kept constant. The film formation time T is kept constant.

[0102] That is, in the prior art, the angle θ of the conductance valve is automatically controlled so that the pressure P in the vacuum chamber is constant while the sputtering power Es is kept constant. In contrast, in this embodiment, the angle θ of the conductance valve 22 is kept constant, and the sputtering power Es is automatically controlled so that the pressure P in the vacuum chamber 12 is constant. In these respects, the configurations of this embodiment and the prior art are fundamentally different from each other. Due to this difference in configuration, this embodiment has the extremely beneficial effect of being able to form a titanium nitride film with better reproducibility than the prior art, and in particular, being able to obtain better reproducibility in the film thickness and color tone of the titanium nitride film.

[0103] FIG. 13 shows the difference in film thickness and color tone ΔL between this embodiment and the prior art. * ,Δa * and Δb * 13. As is clear from Fig. 13, according to this embodiment, better reproducibility of film thickness and color tone can be obtained compared with the prior art.

[0104] As described above, this embodiment stabilizes the sputtering rate, thereby improving the reproducibility of reactive films such as titanium nitride films, and in particular the reproducibility of film thickness and color tone. This contributes greatly to the development of decorative products, for example.

[0105] It should be noted that this embodiment is merely a specific example of the present invention and does not limit the technical scope of the present invention. The present invention can also be applied to aspects other than this embodiment.

[0106] For example, although the present embodiment has been described with reference to the formation of a titanium nitride film as a reaction film, the present invention can also be applied to the formation of various reaction films other than titanium nitride, such as nitride films, carbonitride films, and carbide films. The various reaction films referred to here include titanium carbonitride (TiCN) film, titanium carbide (TiC) film, titanium oxide (TiO2) film, zirconium nitride (ZrN) film, zirconium carbonitride (ZrCN) film, zirconium carbide (ZrC) film, titanium aluminum nitride (TiAlN) film, titanium aluminum carbonitride (TiAlCN) film, aluminum chromium nitride (AlCrN) film, chromium nitride (CrN) film, chromium carbonitride (CrCN) film, chromium carbide (CrC) film, aluminum nitride (AlN) film, aluminum oxide (Al2O3) film, silicon nitride (SiN), silicon carbonitride (SiCN) film, silicon carbide (SiC) film, silicon oxide (SiO2) film, and yttrium oxide (YO3) film. In this case, a target 242 made of a material appropriate for the type of reactive film is used. When a carbonitride film is formed, a hydrocarbon gas such as acetylene (C2H2) gas is used as the reactive gas in addition to nitrogen gas. When a carbonitride film is formed, a hydrocarbon gas such as acetylene is used as the reactive gas instead of nitrogen gas. Furthermore, when an insulating reactive film such as an aluminum nitride film or a silicon nitride film is formed, a pulse power supply that outputs bipolar pulse power similar to the bias power supply 50 is used as the sputtering power supply 28, rather than a DC power supply.

[0107] Furthermore, although a pulse power supply is employed as the bias power supply 50, this is not limiting. For example, if the workpiece 100 is a conductive material and the reaction film to be formed is also a conductive coating, a DC power supply may be employed. Note that even if the workpiece 100 is a conductive material, if the reaction film to be formed is an insulating coating, it is appropriate to employ a pulse power supply or a high-frequency power supply as the bias power supply 50. Furthermore, if the workpiece 100 is an insulating material, a high-frequency power supply is employed as the bias power supply 50.

[0108] 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]

[0109] 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 … branch pipe 58a, 60a ... Opening and closing valve 58b, 60b ... Mass flow controller 62 … Vacuum gauge 64 ... Sputtering power 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 introducing a reactive gas, which is a material for the reaction film, into the vacuum chamber at a constant flow rate; a bias power supply means for supplying bias power having a constant predetermined component to the vacuum chamber and the workpiece, with the vacuum chamber as an anode and the workpiece as a cathode, for accelerating the inert gas particles, the reactive gas particles, 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; and a sputtering power control means for controlling the sputtering power so that the pressure inside the vacuum chamber is kept constant while the effective pumping speed is kept constant by the conductance valve;

2. 2. The film forming apparatus according to claim 1, wherein the sputtering power control means controls the sputtering power so that the pressure inside the vacuum chamber is constant within a range that is lower than the pressure inside the vacuum chamber when the inert gas and the reactive gas are introduced into the vacuum chamber in parallel and higher than the pressure inside the vacuum chamber when only the inert gas is introduced into the vacuum chamber, with the sputtering power set to zero and the effective exhaust speed kept constant by the conductance valve.

3. the arc discharge power supply means is a DC constant voltage power supply device, 2. The film deposition apparatus according to claim 1, further comprising a heating power control means for controlling the heating power so that a current component of the arc discharge power is constant.

4. The film forming apparatus according to claim 1 , wherein the bias power is DC power, asymmetric bipolar pulse power, or high frequency power.

5. 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 introducing a reactive gas, which is a material for the reactive film, into the vacuum chamber at a constant flow rate; 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 inert gas particles, the reactive gas particles, 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, to accelerate the thermoelectrons toward the earth shield; and a sputtering power control step of controlling the sputtering power so that the pressure inside the vacuum chamber is kept constant while the effective pumping speed is kept constant by the conductance valve.

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