Film deposition apparatus by magnetron sputtering method and film deposition method

Abstract

To form a reactive film with a good repeatability by stabilizing a sputtering speed in a film deposition apparatus by a magnetron sputtering method and a film deposition method.SOLUTION: In a magnetron sputtering apparatus 10 according to the invention, an inert gas as a discharge gas is supplied to a vacuum chamber 12 at a constant flow rate Qd. In addition, an angle θ of a conductance valve 22 is set constant, leading an actual exhaust speed at an exhaust port 14 of the vacuum chamber 12 constant. In addition, an electric power for an arc-discharge power Ed is set constant as well as a sputtering electric power Es being set constant. Furthermore, a flow rate Qr of a reactive gas introduced to the vacuum chamber 12 is automatically controlled such that a pressure P in the vacuum chamber 12 becomes constant. With this, a sputtering speed is stabilized. In addition, a substrate bias voltage Vb is set constant. With this, a repeatability of the reactive film is improved, especially a repeatability of a film thickness and a color tone being improved.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film formation apparatus and a film formation method using a magnetron sputtering method, and more particularly to a film formation apparatus and a film formation method using a so-called reactive magnetron sputtering method for forming a reactive film (compound film) on a processing target. [Background technology]

[0002] An 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 that is a material for a reactive film is provided in a vacuum chamber that is set to a ground potential. In addition, a workpiece is provided in the vacuum chamber so as to face the sputtering surface of the target. Furthermore, an earth shield is provided so as to surround the outer periphery of the magnetron sputtering cathode with the sputtering surface of the target (only) of the magnetron sputtering cathode exposed. This earth shield is also set to a ground potential. Then, the inside of the vacuum chamber is evacuated by a vacuum pump as an exhaust means, and an inert gas is introduced into the vacuum chamber as a discharge gas. In this state, the vacuum chamber is used as an anode, strictly speaking the earth shield is used as an anode, and the magnetron sputtering cathode is used as a cathode, and sputtering power is supplied to both of them. As a result, particles of the inert gas are discharged, and magnetron plasma is generated so as to stick to the sputtering surface of the target. The discharge mode of this magnetron plasma is a high-voltage, low-current glow discharge. Moreover, the magnetron plasma sticks to the surface of the target to be sputtered due to the action of a magnetic field formed by a magnet serving as a 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 sputtered surface of the target, so that the particles constituting the target are knocked out of the sputtered surface, that is, sputtered. At this time, the sputtered area, which is the area to be sputtered, is limited to the sputtered surface of the target, that is, the above-mentioned earth shield is provided so that this is the case. Furthermore, a reactive gas that is the material of the reaction film is introduced into the vacuum chamber. The particles of this reactive gas are decomposed by the magnetron plasma. Then, the vacuum chamber is used as the anode, and the workpiece is used as the cathode, and bias power is supplied to both of them. As a result, the particles of the inert gas, the particles of the reactive gas, and the sputtered particles sputtered from the sputtered surface of the target are accelerated toward the workpiece. In particular, the particles of the reactive gas and the sputtered particles adhere to the surface of the workpiece and react with each other, so that a reaction film containing the particles of the reactive gas and the sputtered particles is formed on the surface of the workpiece. In addition, the density of the reaction film is improved by the bombardment action of the particles of the inert gas on the surface of the workpiece.

[0004] In addition, a cathode filament (filament) is provided between the sputtering surface of the target and the workpiece in the vacuum chamber. The cathode filament is heated by supplying heating power (thermionic emission power) to heat the cathode filament, and thermoelectrons are emitted from the cathode filament. Furthermore, the vacuum chamber is used as the anode, and more precisely, the earth shield is used as the anode and the cathode filament is used as the cathode, and arc discharge power (discharge power) is supplied to both of them. Then, the thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, and the accelerated thermoelectrons collide with the particles of the inert gas, the particles of the reactive gas, and the sputter particles. Since the aforementioned magnetic field is formed around the cathode filament, the electrons accelerated from the cathode filament toward the earth shield make a spiral motion (cycloid motion or trochoid motion) due to the effect of the magnetic field. This increases the frequency with which the thermoelectrons collide with the particles of the inert gas, the particles of the reactive gas, and the sputter particles, and induces a low-voltage, high-current arc discharge around the cathode filament. That is, in addition to magnetron plasma due to glow discharge, 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, the sputtered particles sputtered from the sputtered surface of the target pass through a space of extremely high density plasma while flying toward the workpiece. As a result, the sputtered particles are activated and have energy at least higher than that of the ground state, and are ionized particularly efficiently. Similarly, the particles of the reactive gas are also activated and ionized efficiently. At the same time, the particles of the inert gas are also activated and ionized efficiently. This improvement in the ionization rate increases the amount of ions incident on the surface of the workpiece, and the hardness of the reaction film formed on the surface of the workpiece is increased. In addition, the mutual bonding force between the sputtered particles and the particles of the reactive gas is increased, and the reaction film is densified. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-66483 A Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, although not specified in Patent Document 1, the exhaust means described above has, in addition to the vacuum pump, a conductance valve provided in the middle of 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 controls the effective exhaust speed at the exhaust port of the vacuum chamber by the angle θ of the blade members. 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 in the vacuum chamber is constant, in other words, the pressure P in the vacuum chamber is used as a parameter.

[0008] However, the technique disclosed in Patent Document 1 has a problem in that it is not possible to obtain reproducibility of the reaction film, particularly in terms of 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 since it cannot be measured directly, it is usually expressed as the mass of particles sputtered per unit time (g / min)) of the sputtered surface of the target changes every 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 tone of the reaction film is influenced by the composition of the reaction film. Taking a titanium nitride (TiN) film as an example of the reaction film, past experience has shown that the color tone of a titanium nitride film with a stoichiometric composition is gold, but when the composition deviates from the stoichiometric composition, for example, the more titanium atoms there are than nitrogen, the more the gold color tends to fade, and when the number of titanium atoms is twice that of nitrogen (Ti2N), the color tone becomes metallic (silver). When observing the sputtered surface of the target after the titanium nitride film formation process, the titanium nitride film is attached to the non-eroded area of ​​the sputtered surface, and the titanium nitride film is not attached to the eroded area. The appearance of the area near the boundary between the eroded area and the non-eroded area varies from batch to batch, for example, in some cases it is light gold, and in other cases it is metallic. As described above, in the vacuum chamber, magnetron plasma is generated so as to stick to the sputtered surface of the target, and in addition, extremely high-density plasma is generated by arc discharge, so that the space to which the sputtered surface is exposed is chemically very active. Therefore, when the sputtered surface of the target is viewed microscopically, it is considered that nitrogen has penetrated near the boundary between the eroded and non-eroded regions, that is, the boundary is nitrided (or a phenomenon similar to nitriding has occurred). Since the degree of nitriding differs from batch to batch, the sputtering rate changes from batch to batch, in other words, even over a relatively short period (short span), and this changes the composition ratio of the titanium nitride film, which in turn makes it impossible to obtain reproducible color tones of the titanium nitride film.

[0010] Furthermore, when the sputtering rate changes, the formation rate (film-forming rate) of the reaction film changes, and the film thickness of the reaction film changes. In particular, as the batch is repeated (long span), the sputtering rate decreases, the formation rate of the reaction film decreases, and the film thickness of the reaction film tends to become smaller. For example, if the thickness dimension of the target is 8 mm and the target is used until the depth dimension of the erosion region becomes 7 mm, the surface area of ​​the erosion region of the target at the end of use is about 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 decreases by about 10% compared to the power density of the sputtering power acting on the target at the beginning of use. Therefore, as described above, as the batch is repeated, the sputtering rate decreases, and thus the film-forming rate of the reaction film decreases, and as a result, the film thickness of the reaction film tends to become smaller.

[0011] Therefore, an object of the present invention is to provide a novel technique capable of improving the reproducibility of reactive films by stabilizing the sputtering rate in a film formation apparatus and a 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, the first invention relating to a film forming apparatus using a reactive magnetron sputtering method includes a vacuum chamber, a magnetron sputtering cathode, an earth shield, an exhaust means, an inert gas introduction means, a sputtering power supply means, a reactive gas introduction means, a bias power supply means, a cathode filament, a heating power supply means, an arc discharge power supply means, a heating power control means, and a reactive gas flow rate control means. Specifically, the vacuum chamber is grounded, that is, set to a ground potential, and a workpiece is accommodated inside the vacuum chamber. The magnetron sputtering cathode has a target that is a material for a reactive film, and is provided inside the vacuum chamber so that the sputtered surface of the target faces the workpiece. The earth shield is provided so as to surround the outer periphery of the magnetron sputtering cathode with the sputtered area (only) of the target of the magnetron sputtering cathode exposed. The earth shield is also grounded, that is, set to a ground potential. The exhaust means includes a vacuum pump and a conductance valve. The vacuum pump evacuates the inside of the vacuum chamber through the exhaust port of the vacuum chamber. The conductance valve controls the effective exhaust speed at the exhaust port of the vacuum chamber. The inert gas introduction means introduces an inert gas as a discharge gas into the vacuum chamber at a constant flow rate. The sputtering power supply means supplies sputtering power to the vacuum chamber, or more precisely, the earth shield, which serves as the anode, and the magnetron sputtering cathode, which serves as the cathode. This causes particles of the inert gas to discharge, generating magnetron plasma that adheres to the sputtered surface of the target. The discharge mode of this magnetron plasma is a high-voltage, low-current glow discharge. The magnetron plasma adheres to the sputtered surface of the target due to the action of a magnetic field formed by a magnetic field forming means provided in the magnetron sputtering cathode.

[0014] Particles of the inert gas in the magnetron plasma, particularly ions, collide with the sputtered surface of the target, knocking out particles constituting the target from the sputtered surface, i.e., sputtering. At this time, the sputtered area, which is the area to be sputtered, is limited to the sputtered surface of the target, in other words, the above-mentioned earth shield is provided so that this is the case. Furthermore, the reactive gas introduction means introduces a reactive gas that is the material of the reactive film into the inside of the vacuum chamber. The particles of this reactive gas are decomposed by the magnetron plasma. Then, the bias power supply means supplies a constant bias power with a predetermined component to both the vacuum chamber as the anode and the workpiece as the cathode. As a result, the particles of the inert gas, the particles of the reactive gas, and the sputtered particles sputtered from the sputtered surface of the target are accelerated toward the workpiece at a constant acceleration. In particular, the particles of the reactive gas and the sputtered particles adhere to the surface of the workpiece and react with each other, forming a reactive film composed of the particles of the reactive gas and the sputtered particles on the surface of the workpiece. In addition, the density of the reaction film is improved by the bombardment of the surface of the workpiece by the particles of the inert gas. 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] In addition, the cathode filament is provided between the sputtering surface of the target and the workpiece inside the vacuum chamber. The heating power supply means supplies heating power to the cathode filament to heat the cathode filament and emit thermoelectrons from the cathode filament. The arc discharge power supply means supplies arc discharge power to the vacuum chamber as the anode, more precisely, the earth shield as the anode, and the cathode filament as the cathode. Then, the thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, and the accelerated thermoelectrons collide with the inert gas particles, the reactive gas particles, and the sputter particles. Since the aforementioned magnetic field is formed around the cathode filament, the electrons accelerated from the cathode filament toward the earth shield make a spiral motion due to the effect of the magnetic field. This increases the frequency with which the thermoelectrons collide with the inert gas particles, the reactive gas particles, and the sputter particles, and induces a low-voltage, high-current arc discharge around the cathode filament. That is, in addition to magnetron plasma due to glow discharge, 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, the sputtered particles sputtered from the sputtered surface of the target pass through a space of extremely high density plasma while flying toward the workpiece. As a result, the sputtered particles are activated and efficiently ionized. Similarly, the particles of the reactive gas are also activated and efficiently ionized. At the same time, the particles of the inert gas are also activated and efficiently ionized. This improvement in the ionization rate increases the amount of ions incident on the surface of the workpiece, and the hardness of the reaction film formed on the surface of the workpiece is increased. In addition, the mutual bonding force between the sputtered particles and the particles of the reactive gas is increased, and the reaction film is made denser.

[0017] The heating power control means controls the heating power so that the current component of the arc discharge power, that is, the arc discharge, becomes constant while the voltage component of the arc discharge power, that is, the arc discharge voltage, is kept constant, thereby stabilizing the density of the plasma caused by the arc discharge.

[0018] Furthermore, the reactive gas flow rate control means controls the flow rate of the reactive gas into the vacuum chamber, for example, by controlling the reactive gas introduction means, so that the pressure inside the vacuum chamber is constant. At this time, the sputtering power is kept constant. In addition, the effective exhaust speed at the exhaust port of the vacuum chamber by the vacuum pump is kept constant by the conductance valve. This keeps the sputtering speed constant.

[0019] In the first invention, a plurality of units may be provided. The unit referred to here is, so to speak, a plasma generation source having a magnetron sputtering cathode, an earth shield, a sputtering power supply means, a cathode filament, a heating power supply means, an arc discharge power supply means, and a heating power control means. In other words, a plurality of units serving as plasma generation sources may be provided.

[0020] In addition, as the bias power, DC power, asymmetric bipolar pulse power, or high frequency power is selectively adopted depending on whether the workpiece 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] The second invention of the present invention, which relates to a film forming method by reactive magnetron sputtering, includes a workpiece placement step, an exhaust step, an inert gas introduction step, a sputtering power supply step, a reactive gas introduction step, a bias power supply step, a heating power supply step, an arc discharge power supply step, a heating power control step, and a reactive gas flow rate control step. In the workpiece placement step, the workpiece is placed inside a vacuum chamber in which a magnetron sputtering cathode having a target that is a material for a reactive film is provided, so as to face the sputtering surface of the target. Here, the vacuum chamber is grounded, that is, set to a ground potential. Then, an earth shield is provided so as to surround the outer periphery of the magnetron sputtering cathode with (only) the sputtering surface of the target of the magnetron sputtering cathode exposed. This earth shield is also grounded, that is, set to a ground potential. In the exhaust step, the inside of the vacuum chamber is exhausted by a vacuum pump through an exhaust port of the vacuum chamber. In addition, the effective exhaust speed at the exhaust port of the vacuum chamber is controlled by a conductance valve. In the inert gas introduction step, an inert gas is introduced into the vacuum chamber at a constant flow rate as a discharge gas. In the sputtering power supply step, the vacuum chamber is used as the anode, or more precisely, the earth shield is used as the anode, and the magnetron sputtering cathode is used as the cathode, and sputtering power is supplied to both of them. This causes particles of the inert gas to discharge, generating magnetron plasma that sticks to the sputtering surface of the target. The discharge mode of this magnetron plasma is a high-voltage, low-current glow discharge. The magnetron plasma sticks to the sputtering surface of the target due to the action of a magnetic field formed by a magnetic field forming means provided in the magnetron sputtering cathode.

[0022] Particles of the inert gas in the magnetron plasma, particularly ions, collide with the sputtered surface of the target, so that the particles constituting the target are knocked out from the sputtered surface, that is, sputtered. At this time, the sputtered area, which is the area to be sputtered, is limited to the sputtered surface of the target, that is, the above-mentioned earth shield is provided so that this is the case. Furthermore, in the reactive gas introduction step, a reactive gas that is the material of the reactive film is introduced into the vacuum chamber. The particles of this reactive gas are decomposed by the magnetron plasma. Then, in the bias power supply step, the vacuum chamber is used as the anode, the workpiece is used as the cathode, and a constant bias power with a predetermined component is supplied to both of them. As a result, the particles of the inert gas, the particles of the reactive gas, and the sputtered particles sputtered from the sputtered surface of the target are accelerated toward the workpiece at a constant acceleration. In particular, the particles of the reactive gas and the sputtered particles adhere to the surface of the workpiece and react with each other, so that a reactive film containing the particles of the reactive gas and the sputtered particles as components is formed on the surface of the workpiece. In addition, the density of the reaction film is improved by the bombardment of the surface of the workpiece by the particles of the inert gas. 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 addition, in the heating power supply step, heating power is supplied to the cathode filament. The cathode filament is provided between the sputtering surface of the target and the workpiece inside the vacuum chamber. This cathode filament is heated by receiving the heating power and emits thermoelectrons. In the arc discharge power supply step, the vacuum chamber is used as the anode, and more precisely, the earth shield is used as the anode and the cathode filament is used as the cathode, and arc discharge power is supplied to both of them. Then, the thermoelectrons emitted from the cathode filament are accelerated toward the earth shield, and the accelerated thermoelectrons collide with the particles of the inert gas, the particles of the reactive gas, and the sputter particles. Since the above-mentioned magnetic field is formed around the cathode filament, the electrons accelerated from the cathode filament toward the earth shield make a spiral motion due to the action of the magnetic field. As a result, the frequency of collision of the thermoelectrons with the particles of the inert gas, the particles of the reactive gas, and the sputter particles increases, and a low-voltage, high-current arc discharge is induced around the filament. That is, in addition to magnetron plasma due to glow discharge, 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, the sputtered particles sputtered from the sputtered surface of the target pass through a space of extremely high density plasma while flying toward the workpiece. As a result, the sputtered particles are activated and efficiently ionized. Similarly, the particles of the reactive gas are also activated and efficiently ionized. At the same time, the particles of the inert gas are also activated and efficiently ionized. This improvement in the ionization rate increases the amount of ions incident on the surface of the workpiece, and the hardness of the reaction film formed on the surface of the workpiece is increased. In addition, the mutual bonding force between the sputtered particles and the particles of the reactive gas is increased, and the reaction film is made denser.

[0025] In the heating power control step, the heating power is controlled so that the current component of the arc discharge power, i.e., the arc discharge, is kept constant while the voltage component of the arc discharge power, i.e., the arc discharge voltage, is kept constant, thereby stabilizing the density of the plasma caused by the arc discharge.

[0026] Furthermore, in the reactive gas flow rate control step, the flow rate of the reactive gas into the vacuum chamber is controlled so that the pressure inside the vacuum chamber is kept constant. At this time, the sputtering power is kept constant. In addition, the effective exhaust speed at the exhaust port of the vacuum chamber by the vacuum pump is kept constant by the conductance valve. This keeps the sputtering speed constant. Effect of the Invention

[0027] 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 description of the drawings]

[0028] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a magnetron sputtering apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a top view of the inside of a magnetron sputtering apparatus according to an embodiment of the present invention. [Diagram 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. [Diagram 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 an experimental result according to an embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing film formation conditions in another experiment according to an embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing the properties of a titanium nitride film formed in another experiment according to an embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a comparison of various control procedures according to an embodiment of the present invention and a conventional technique for comparison. [Figure 10] FIG. 10 is a diagram showing a comparison of the reproducibility of titanium nitride films formed by an embodiment of the present invention and a conventional technique for comparison. [Figure 11] FIG. 11 is a diagram showing an expanded example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0030] As shown in Fig. 1 and Fig. 2, the magnetron sputtering apparatus 10 according to the present embodiment includes a vacuum chamber 12 having a generally cylindrical shape with both ends closed. The vacuum chamber 12 is installed with both ends of the generally cylindrical shape facing up and down, that is, with the central axis Xa of the cylinder extending vertically. The inner diameter of the vacuum chamber 12 is, for example, about 1100 mm, and the height dimension inside the vacuum chamber 12 is, for example, about 800 mm. The shape and dimensions of the vacuum chamber 12 are merely examples, and are appropriately determined depending on various circumstances such as the size, shape, and number of the workpieces 100 to be treated, which will be described later. The vacuum chamber 12 itself is made of a metal having high corrosion resistance and heat resistance, for example, stainless steel such as SUS304, and its wall is grounded, that is, the potential of the wall is set to the ground potential, which is the reference potential.

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

[0032] A main valve, i.e., an on-off valve 20, is provided in 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 in 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. The vacuum pump 18 and the conductance valve 22 constitute an exhaust means. Although not shown in detail, the conductance valve 22 has a plurality of elongated plate-like blade members arranged in parallel like blinds, and the effective pumping speed at the exhaust port 14 of the vacuum chamber 12 is controlled by the angle θ of the blade members. For example, the smaller the angle θ of the conductance valve 22 (blade member), the larger the conductance, and when the angle θ is 0 degrees, the valve is fully open. Conversely, the larger the angle θ of the conductance valve 22, the smaller the conductance, and when the angle θ is 90 degrees, the valve 22 is fully closed. Such a configuration of the conductance valve 22 is merely an example and is not limiting.

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

[0034] The magnetron sputtering cathode 24 is provided so that the sputtered 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., along the vertical direction. The magnetron sputtering cathode 24 is covered by the earth shield 26 except for the sputtered surface of the target 242. In other words, the earth shield 26 is provided so as to surround the outer periphery of the magnetron sputtering cathode 24 with the sputtered surface of the target 242 of the magnetron sputtering cathode 24 (only) exposed. The earth shield 26 is made of a metal having high corrosion resistance and heat resistance, for example, stainless steel such as SUS304. The earth shield 26 is electrically insulated from the magnetron sputtering cathode 24 and electrically connected to the wall of the vacuum chamber 12, i.e., is at ground potential.

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

[0036] 2, the portion 12a of the wall of the vacuum chamber 12 on which 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, it is desirable for this portion 12a to be able to be opened and closed like a sliding door or a hinged door.

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

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

[0039] 4, particularly FIG. 4(a), the cathode filament 30 is provided so as to extend vertically through the center of the sputtered surface of the target 242, that is, along the longitudinal direction of the target 242, in other words, parallel to the sputtered surface of the target 242, when viewed from the opposite side to the direction in which the magnetron sputtering cathode 24 is arranged in the horizontal direction, for example, from the central axis Xa side of the vacuum chamber 12. As shown in FIG. 4(b) and FIG. 4(c), the cathode filament 30 is provided with an appropriate distance D between it and the sputtered surface of the target 242. If the distance D is too small, for example, the cathode filament 30 may come into contact with the sputtered surface of the target 242 or the earth shield 26, which is extremely inconvenient. On the other hand, if the distance D is excessively large, the effect of the magnetic field by the magnet unit 244 (permanent magnet 246) around the cathode filament 30 becomes weak, which is inconvenient for inducing an arc discharge, which will be described later. For these reasons, the distance D is suitably about 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 strictly speaking, is 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 in the drawings, a tension applying mechanism is provided at both ends or either one of the ends of the cathode filament 30 as tension applying means for applying an appropriate tension to the cathode filament 30 and maintaining the cathode filament 30 in a linear state.

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

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

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

[0043] The heating controller 38 controls the heating power supply device 32 so that the detection value of the arc discharge current Id 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. That is, the amount of thermoelectrons emitted by the cathode filament 30 is automatically controlled (feedback controlled) using the arc discharge current Id as a parameter.

[0044] Focusing on the inside of the position where the cathode filament 30 is provided in the vacuum chamber 12, a plurality of workpieces 100, 100, ... are arranged in the vacuum chamber 12. Specifically, the workpieces 100, 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 is, for example, elongated and approximately columnar or cylindrical, and is held by a holder 40 as a holding means so as to extend along the vertical direction, that is, in the direction along the central axis Xa of the vacuum chamber 12. Each holder 40 is coupled to the vicinity of the periphery of a disk-shaped revolution table 44 via a gear mechanism 42. The center of this 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 rotating shaft 46 is coupled to a shaft 48a of a motor 48 serving as a rotation drive means outside the vacuum chamber 12.

[0045] That is, when the motor 48 is driven and the shaft 48a of the motor 48 rotates in the direction indicated by the arrow 200 in FIG. 1, the revolving table 44 rotates in the same direction, that is, in the direction indicated by the arrow 200 in FIG. 2. Accordingly, each of the objects to be processed 100 rotates about the central axis Xa of the vacuum chamber 12, so to speak, revolves. In addition, due to the rotational drive force transmission action of each of the gear mechanisms 42, each of the holders 40 rotates about the vertical line Xb passing through the holder 40, for example, in the direction indicated by the arrow 202 in each of FIG. 1 and FIG. 2. Then, with the rotation of the holder 40 itself, the object to be processed 100 also rotates in the same direction, so to speak, spins on its own axis. The diameter (PCD) of the revolution path of the object to be processed 100 is, for example, about 600 mm. The revolution speed of the object to be processed 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. Although Fig. 1 and Fig. 2 show an example in which the number of workpieces 100 (holders 40 and gear mechanisms 42) is 12, the number of workpieces 100 is not limited to this. In addition, the shape of the workpieces 100 is not limited to the above-mentioned elongated approximately columnar or approximately cylindrical shape.

[0046] Additionally, each workpiece 100 is supplied with substrate bias power Eb from a bias power supply device 50, which is an example of a bias power supply means located outside the vacuum chamber 12, via the holder 40, the gear mechanism 42, the revolving table 44, and the rotating shaft 46. This substrate bias power Eb is a so-called asymmetric bipolar pulse power in which the substrate bias voltage Vb, which is a voltage component of the substrate bias power Eb, alternates between a high level value of a positive potential with respect to the ground potential as a reference and a low level value of a negative potential with respect to the ground potential as a reference. The high level value of the substrate bias voltage Vb is constant, for example, +37V with respect to the ground potential as a reference. On the other hand, 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 within a range of, for example, 50kHz to 250kHz. 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 period 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, rather than the average value of the substrate bias voltage Vb.

[0047] Furthermore, a carbon heater 52, for example, is provided as a temperature control means at an appropriate position inside the wall portion forming the side surface of the vacuum chamber 12 and at an appropriate position outside the revolution path of each of the workpieces 100, 100, ..., for example, at a position opposite the position where the magnetron sputtering cathode 24 is provided across the central axis Xa of the vacuum chamber 12 (the left position in Figs. 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 to generate heat, thereby heating the inside of the vacuum chamber 12, and in particular heating each of the workpieces 100, 100, .... As shown in FIG. 2, the portion 12b of the wall of the vacuum chamber 12 on which the carbon heater 52 is provided is also structured appropriately for providing the carbon heater 52, similar to the portion 12a on which the magnetron sputtering cathode 24 and earth shield 26 are provided.

[0048] 1, a gas inlet 54 for introducing various gases such as an inert gas into the vacuum chamber 12 is provided at an appropriate position in 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 embodiment, are connected to the gas inlet pipe 56.

[0049] One branch pipe 58 is a pipe for introducing an inert gas as a discharge gas into the vacuum chamber 12, and is connected to a supply source (not shown) of the inert gas. The branch pipe 58 for introducing the inert gas is provided with an opening / closing valve 58a as an opening / closing means for opening and closing the inside of the branch pipe 58, and a mass flow controller 58b as a flow control means for controlling a flow rate Qd of the inert gas flowing through the branch pipe 58. The branch pipe 58 including the opening / closing 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. In addition, argon gas, for example, is used as the inert gas.

[0050] The other branch pipe 60 is a pipe for introducing reactive gas, which is a material for the coating, particularly a material for the reactive film, into the vacuum chamber 12, and is supplied to a supply source (not shown) of the reactive gas. This branch pipe 60 for introducing reactive gas is also provided with an opening / closing valve 60a as an opening / closing means for opening and closing the branch pipe 60, and a mass flow controller 60b as a flow control means for controlling the flow rate Qr of the reactive gas flowing through the branch pipe 60. The branch pipe 60 including the opening / closing valve 60a and the mass flow controller 60b constitutes an example of a reactive gas introduction means in cooperation with the gas introduction pipe 56. As the reactive gas, an appropriate gas is adopted according to the type of the reactive film to be formed. For example, when a nitride film is formed as the reactive film, nitrogen (N2) gas is adopted as the reactive gas, and when a carbonized film is formed as the reactive film, a hydrocarbon gas such as acetylene (C2H2) is adopted as the reactive gas. When an oxide film is formed as the reactive film, oxygen (O2) gas is adopted as the reactive gas.

[0051] In addition, the pressure gauge 62 is provided at an appropriate position in 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 measuring means for measuring the pressure in the vacuum chamber 12, 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 gas flow controller 64, which is an example of a reactive gas flow control means, located outside the vacuum chamber 12. Note that, for example, a diaphragm vacuum gauge capable of measuring absolute pressure with relatively high accuracy and high resolution is used as the pressure gauge 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 described later. The main body of the pressure gauge 62 is provided outside the vacuum chamber 12.

[0052] The gas flow controller 64 controls the mass flow controller 60b for introducing reactive gas 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 flow rate Qr of the reactive gas introduced into the vacuum chamber 12 via the mass flow controller 60b. That is, the flow rate Qr of the reactive gas is automatically controlled (feedback controlled) using the pressure P in the vacuum chamber 12 as a parameter. The gas flow controller 64 may be incorporated into the mass flow controller 60b, for example.

[0053] 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 part closest to the cathode filament 30 in the revolution path of the workpiece 100). This shutter appropriately transitions between an open state in which the sputtering surface of the target 242 of the magnetron sputtering cathode 24 is exposed to the space in which the workpiece 100 is placed, and a closed state in which it is shielded from the space.

[0054] With the magnetron sputtering apparatus 10 configured as above, various reactive films can be formed on the surface of the workpiece 100. For example, a case where a titanium nitride film is formed as the reactive film will be described. In this case, titanium having a purity of 3N or more is used as the target 242. In addition, nitrogen gas having a purity of 5N or more is used as the reactive gas.

[0055] Then, the workpiece 100 is placed in the vacuum chamber 12, that is, attached to the holder 40. The inside of the vacuum chamber 12 is then filled with a vacuum of 2×10 -3 The air is evacuated until a pressure P of about Pa is reached, and so-called vacuum drawing is performed. Thereafter, the motor 48 is driven, and the object 100 starts to rotate and revolve. At the same time, heater heating power is supplied to the carbon heater 52, and the object 100 is heated to about 150° C. This causes impurity gases contained in the object 100 to be discharged, and so-called degassing is performed.

[0056] 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, a discharge cleaning process is performed. In this discharge cleaning process, a 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, an arc discharge power Ed is supplied to the cathode filament 30. That is, the earth shield 26 is used as an anode, and the cathode filament 30 is used as a cathode, and the arc discharge power Ed is supplied to both of them. As a result, the 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. Then, the accelerated thermoelectrons collide with particles of the argon gas, and the particles of the argon gas are ionized by the impact, and a plasma 300 is generated.

[0057] Here, since 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, the thermoelectrons accelerated from the cathode filament 30 toward the earth shield 26 undergo a spiral motion due to the effect of the magnetic field. As a result, the frequency with which the thermoelectrons collide with argon gas particles increases, and the plasma 300 becomes denser. The discharge mode of such plasma 300 is a low-voltage, high-current arc discharge.

[0058] The arc discharge is induced, for example, even when the pressure P inside the vacuum chamber 12 is in the range of 0.01 Pa to 1 Pa, that is, even when the pressure P is relatively low. The arc discharge power Ed is kept constant, more specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, is kept constant, and the cathode power Ec is controlled so that the arc discharge current Id, which is the current component of the arc discharge power Ed, is kept constant, that is, the amount of thermoelectrons emitted from the cathode filament 30 is controlled. This stabilizes the density of the plasma caused by the arc discharge.

[0059] With the plasma 300 generated by this arc discharge, 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 substrate bias power Eb is supplied to both. Then, argon particles in the plasma 300, particularly argon ions, are actively injected into the surface of the workpiece 100. This impact removes impurities from the surface of the workpiece 100, and a so-called discharge cleaning process is performed. Since the workpiece 100 rotates and revolves around its axis as described above, the discharge cleaning process is performed when it is exposed to the plasma 300 during this rotation and revolution process.

[0060] After this discharge cleaning process is performed for a predetermined time (for example, about 30 minutes), a film forming process is performed to form a titanium nitride film. For this purpose, sputtering power Es is supplied to magnetron sputtering cathode 24. That is, sputtering power Es is supplied to both earth shield 26 as an anode and magnetron sputtering cathode 24 as a cathode. Then, argon ions in plasma 300 collide with the sputtered surface of target 242 of magnetron sputtering cathode 24, and titanium particles are knocked out from the sputtered surface of target 242, that is, sputtered. At this time, the sputtered area, which is the area to be sputtered, is limited to the sputtered surface of target 242, that is, earth shield 26 is provided so as to make this the case. Furthermore, nitrogen gas is introduced into vacuum chamber 12 as a reactive gas. The nitrogen gas particles are decomposed by plasma 300.

[0061] As described above, titanium particles as sputtered particles sputtered from the sputtered 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 to form a titanium nitride film, which is a reaction film containing titanium particles and nitrogen particles as components, 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 the 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.

[0062] 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, the plasma 300 includes (combines) magnetron plasma due to glow discharge in addition to the above-mentioned arc discharge. This magnetron plasma due to glow discharge is generated so as to stick to the sputtering surface of the target 242 due to the action of the magnetic field from the above-mentioned permanent magnet 246.

[0063] Then, the titanium particles, nitrogen particles, and argon particles pass through the space of the extremely high-density plasma 300 while flying toward the workpiece 100. As a result, the titanium particles, nitrogen particles, and argon particles are more activated and more efficiently ionized. This improvement in the ionization rate increases the amount of ions incident on the surface of the workpiece 100, and the hardness of the titanium nitride film formed on the surface of the workpiece 100 is increased. In addition, the mutual bonding force between the titanium particles and the nitrogen particles increases, and the titanium nitride film is made denser.

[0064] In this film formation process, similarly to the above-mentioned discharge cleaning process, the workpiece 100 is subjected to the film formation process while being 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 the range of 0.1 Pa to 1 Pa, for example.

[0065] 4, when attention is paid to the sputtered surface of the target 242, the density of the plasma 300 becomes higher in the vicinity of the sputtered surface where the plasma 300 is generated, in a region following the gap 246c of the permanent magnet 246. Therefore, the region of the sputtered 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 magnet 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 magnet 246 appear on the sputtered surface of the target 242, that is, erosion regions 242a are formed.

[0066] After this film formation process is performed for a predetermined time (the time required to form a titanium nitride film with 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. Then, while the inside of the vacuum chamber 12 is maintained at a high vacuum by the vacuum pump 18, it is waited for the inside of the vacuum chamber 12 to drop to a predetermined temperature (for example, 150°C), that is, an appropriate cooling period is placed. Then, the driving of the motor 48 is stopped, and the rotation and revolution of the workpiece 100 are stopped. Then, the inside of the vacuum chamber 12 is opened to the outside, and the workpiece 100 is taken out from the vacuum chamber 12 to the outside. With this, a series of processes including the film formation process for forming a titanium nitride film is completed.

[0067] In the explanation of this series of processes, particularly in the explanation of the film forming process, the gas flow controller 64 has not been mentioned in particular. However, as described above, the gas flow controller 64 controls the mass flow controller 60b for introducing reactive gas so that the pressure P in the vacuum chamber 12 is constant, and more specifically, controls the flow rate Qr of the reactive gas introduced into the vacuum chamber 12 via the mass flow controller 60b. On the other hand, the flow rate Qd of the inert gas is kept constant. In addition, the angle θ (of the blade member) of the conductance valve 22 is kept constant, so that the effective exhaust speed at the exhaust port 14 of the vacuum chamber 12 is kept constant. The action and effect of performing the film forming process in this manner will be described in detail later.

[0068] In contrast, when a film formation process is performed by the so-called conventional technology disclosed in, for example, the above-mentioned Patent Document 1, the flow rate Qd of the inert gas is kept constant, and the flow rate Qr of the reactive gas is also 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.

[0069] 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, this will be expressed by the symbol "Q[Ar]") is kept constant, and the flow rate Qr of nitrogen gas as a reactive gas (hereinafter, this will be expressed by the symbol "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 is kept constant, the sputtering power Es is kept constant, and further, the substrate bias voltage Vb (average value) is kept constant.

[0070] 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 was performed using such conventional technology. The results are shown in Figure 5. Note that Figure 5(a) shows the film formation conditions (film formation conditions) used in this experiment, and Figure 5(b) shows the properties of the titanium nitride film formed by the film formation process, specifically the measurement results of the film thickness and color tone of the titanium nitride film and the film formation rate calculated from the film thickness. Finally, Figure 5(c) shows a photograph of the appearance of the titanium nitride film.

[0071] As shown in FIG. 5(a), in this experiment, the flow rate Q [Ar] of argon gas was set to 100 mL / min (constant), and the flow rate Q [N2] of nitrogen gas was set to 40 mL / min (constant). The pressure P in the vacuum chamber was set to 0.3 Pa (constant), and strictly speaking, the angle θ of the conductance valve was automatically controlled so that this was the case. Furthermore, the arc discharge power Ed was set to 700 W (constant), and more specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant), and 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 (film formation time) T of 80 minutes.

[0072] As a result, as shown in FIG. 5(b), the thickness of the titanium nitride film formed by the first (first batch) film formation process, so-called sample 1, was 0.75 μm. When converted to a film formation speed, the film formation speed was 0.56 μm / h. On the other hand, the thickness of the titanium nitride film formed by the second (second batch) film formation process, so-called sample 2, was 0.96 μm. When converted to a film formation speed, the film formation speed was 0.72 μm. In other words, the film thickness difference between the film thickness of sample 1 and the film thickness of sample 2 was 0.21. This film thickness difference of 0.21 μm is relatively large compared to the film thicknesses of sample 1 and sample 2, which means that good reproducibility of the film thickness cannot be obtained. The difference between the deposition rate for sample 1 and the deposition rate for sample 2 is 0.16 μm / h, which is relatively large in comparison with the deposition rates for sample 1 and sample 2, and indicates that the variation in deposition rate is relatively large. The film thickness was measured by measuring the step using a contact-type surface roughness meter. Silicon (Si) wafers were used as the objects to be processed for film thickness measurement.

[0073] On the other hand, when we look at the color tone, the L * ,a * and b * 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 between these two, ΔL * ,Δa * and Δb * were 4.21, 5.77 and 15.70, respectively. The difference ΔL * ,Δa * and Δb * The values ​​of L for sample 1 and sample 2 are * ,a * and b *In terms of the values ​​of , both are relatively large, which means that good reproducibility of color tone cannot be obtained. The color tone was measured using a color difference meter (CR-400) manufactured by Konica Minolta, Inc. In addition, a mirror-finished SUS304 plate (30 mm x 30 mm x 1 mm) was used as the processing object for color tone measurement.

[0074] Concerning the color tone, as shown in FIG. 5(c), it is clear from the appearance that Sample 1 and Sample 2 are completely different from each other. For example, Sample 1 has a gold color tone specific to titanium nitride films, but Sample 2 has a lighter gold color, so to speak, a whitish gold color tone. In the external photograph shown in FIG. 5(c), in consideration of the ease of viewing the appearance of Sample 1 and Sample 2, tracing paper is placed over Sample 1 and Sample 2, particularly to suppress their respective glosses. Also, a ruler is attached so that the sizes of Sample 1 and Sample 2 can be intuitively understood.

[0075] As is clear from these experimental results, the conventional technology does not provide reproducibility in the thickness and color of the titanium nitride film. The reason for this is presumably that, as described above, the sputtering rate of the sputtered surface of the target changes every time a film-forming process for forming a titanium nitride film is performed, in other words, for each batch, and as the batch is repeated.

[0076] 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 is made constant. The sputtering power Es is made constant, and the angle θ of the conductance valve 22 is made constant, that is, the effective exhaust speed at the exhaust port 14 of the vacuum chamber 12 is made constant. In addition, the flow rate Q [N2] of nitrogen gas as a reactive gas is automatically controlled so that the pressure P in the vacuum chamber 12 is made constant. In addition, the arc discharge power Ed is made constant, and more specifically, the cathode power Ec is automatically controlled so that the arc discharge current Id, which is a current component of the arc discharge power Ed, is made constant while the arc discharge voltage Vd, which is a voltage component of the arc discharge power Ed, is made constant. By performing the film formation process in this manner, the sputtering rate is stabilized. Furthermore, the substrate bias voltage Vb (average value) is made constant. This stabilizes the sputtering rate of the sputtered surface of the target 242, which in turn improves the reproducibility of the titanium nitride film, particularly the thickness and color of the titanium nitride film. This will be described in detail below.

[0077] First, in this embodiment, an experiment was conducted to confirm how the pressure P in the vacuum chamber 12 and the flow rate Q[N2] of the nitrogen gas change when the titanium nitride film is formed. The results are shown in FIG. 6. FIG. 6 shows an example of log data in which the measurement results of the pressure P in the vacuum chamber 12 and the flow rate Q[N2] of the nitrogen gas are recorded in chronological order. FIG. 6 also shows log data of the sputtering power Es and the arc discharge current Id for reference. The horizontal axis of FIG. 6 represents time, and one scale of the horizontal axis corresponds to 10 minutes. The time t0 on the horizontal axis is the time when various controls, including the automatic control of the flow rate Q[N2] of the nitrogen gas, are started. On the other hand, the vertical axis of FIG. 6 represents the flow rate Q[N2] of the nitrogen gas. Therefore, the scales of the vertical axis are irrelevant to the pressure P in the vacuum chamber 12, the sputtering power Es, and the arc discharge current Id other than the flow rate Q[N2] of the nitrogen gas, and only the transition states of each are shown.

[0078] In this experiment, the flow rate Q[Ar] of the argon gas was set to 100 mL / min (constant), the sputtering power Es was set to 8 kW (constant), and the angle θ of the conductance valve 22 was set to 40 degrees. In addition, the pressure P in the vacuum chamber 12 was set to 0.220 Pa (constant), and strictly speaking, the flow rate Q[N2] of the nitrogen gas was automatically controlled so that this was the case. In addition, the arc discharge power Ed was set to 700 W (constant), and more specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant), and 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).

[0079] In FIG. 6 showing the results of this experiment, for example, if we look at the flow rate Q[N2] of nitrogen gas, the flow rate Q[N2] of nitrogen gas shows a constant value of 40 mL / min until just before the time t0 when the automatic control is started. In other words, the flow rate Q[N2] of nitrogen gas is controlled by the mass flow controller 60b to a constant value of 40 mL / min until just before the time t0. Then, after the time t0, the flow rate Q[N2] of nitrogen gas is automatically controlled, so that the flow rate Q[N2] of nitrogen gas becomes a value corresponding to the pressure P in the vacuum chamber 12. Note that the pressure P in the vacuum chamber 12 after the time t0 basically becomes the constant value of 0.220 Pa described above, that is, the flow rate Q[N2] of nitrogen gas is automatically controlled so that it becomes this value.

[0080] Now, looking at the pressure in the vacuum chamber 12 after time t0, the pressure P in the vacuum chamber 12 fluctuates slightly (subtly) and occasionally rises instantaneously. In response to this (so to speak, in synchronization), the flow rate Q[N2] of the nitrogen gas also fluctuates slightly and occasionally decreases instantaneously, that is, when the pressure in the vacuum chamber 12 rises instantaneously, specifically from a value of about 40 mL / min to a value of about 30 mL / min. Note that the period during which the pressure P in the vacuum chamber 12 rises instantaneously, in other words, the period during which the flow rate Q[N2] of the nitrogen gas decreases instantaneously, is not constant, but is indefinite in the range of several minutes to several tens of minutes. Also, the time during which the pressure P in the vacuum chamber 12 is in an instantaneous state, in other words, the time during which the flow rate Q[N2] of the nitrogen gas is in an instantaneous state, is several seconds, specifically 2 to 3 seconds.

[0081] From such transitions in the pressure P within the vacuum chamber 12 and the flow rate Q of the nitrogen gas [N2], it is presumed that the following phenomenon occurs in the film formation process of the titanium nitride film.

[0082] That is, in the film formation process of the titanium nitride film, it is considered that the vicinity of the boundary between the erosion region 242a and the non-erosion region of the sputtered surface of the target 242 is nitrided as described above. This nitridation reduces the amount of titanium particles sputtered from the sputtered surface of the target 242, and accordingly reduces the amount of nitrogen gas particles reacting with the titanium particles (sputtered particles), that is, the amount of nitrogen gas particles consumed by reacting with the titanium particles is reduced. As a result, the pressure P in the vacuum chamber 12 increases. In response to this, the flow rate Q[N2] of the nitrogen gas is automatically controlled so that the pressure P in the vacuum chamber 12 is constant, and the flow rate Q[N2] of the nitrogen gas is rapidly reduced, specifically, from a value of about 40 mL / min to a value of about 30 mL / min as described above. Then, the ratio (relative ratio) of the amount of argon gas particles to the amount of nitrogen gas particles in the vacuum chamber 12 increases, and this increases the frequency (number of times) of collision of argon gas particles, especially argon ions, with the sputtered surface of the target 242. As a result, the nitride layer formed on the sputtered surface of the target 242 by the above-mentioned nitriding is scraped off by the argon ions, and the amount of titanium particles sputtered from the sputtered surface of the target 242 increases. The amount of nitrogen gas particles consumed by reacting with the increased titanium particles increases, and the pressure P in the vacuum chamber 12 decreases accordingly. In response to this, in order to compensate for the decrease in pressure P in the vacuum chamber 12, in other words to replenish the nitrogen gas particles required to react with the increased titanium particles, the flow rate Q [N2] of the nitrogen gas increases and returns to the initial value of about 40 mL / min. It is presumed that the pressure in the vacuum chamber 12 momentarily increases and the flow rate [N2] of the nitrogen gas momentarily decreases as described above by repeating such a phenomenon. In addition, since the degree of nitridation of the sputtered surface of target 242 and the concentration of nitrogen gas in vacuum chamber 12 are not constant, it is presumed that the period in which the pressure P in vacuum chamber 12 momentarily increases and the flow rate Q[N2] of nitrogen gas momentarily decreases is not constant, i.e., there is no regularity in the period.

[0083] In this way, while the pressure P inside the vacuum chamber 12 momentarily rises and the flow rate Q [N2] of the nitrogen gas momentarily decreases from time to time, the nitride layer formed on the sputtered surface of the target 242 is appropriately scraped off, so to speak, refreshing the sputtered surface of the target 242. This stabilizes the sputtering rate on the sputtered surface of the target 242, thereby improving the reproducibility of the titanium nitride film, particularly the film thickness and color tone.

[0084] To verify this, an experiment was conducted in this embodiment to determine whether a titanium nitride film was actually formed and whether its reproducibility, particularly in terms of color tone and film thickness, could be obtained. Figure 7 shows the film formation conditions in this experiment, and Figure 8 shows the properties of the titanium nitride film formed by this experiment.

[0085] Specifically, as shown in FIG. 7, in this experiment, the flow rate Q[Ar] of the argon gas was set to 100 mL / min (constant), the angle θ of the conductance valve 22 was set to 40 degrees (constant), and the flow rate Q[N2] of the nitrogen gas was automatically controlled so that the pressure P in the vacuum chamber 12 was 0.220 Pa (constant). Then, the arc discharge power Ed was set to 1000 W (constant), and more specifically, the arc discharge voltage Vd, which is the voltage component of the arc discharge power Ed, was set to 50 V (constant), and 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 20 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 10 times (10 batches) over a period (film formation time) T of 65 minutes.

[0086] For each of the titanium nitride films formed by these 10 film formation processes (batches), the thickness and L * ,a * and b *When these were measured, the results shown in FIG. 8 were obtained. The film thickness was measured by measuring the step difference using a contact surface roughness meter, as in the experiment on film thickness in the prior art described above, and a silicon wafer was used as the workpiece for film thickness measurement. The color tone was also measured 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, and a mirror-finished SUS304 plate (30 mm×30 mm×1 mm) was used as the workpiece 100 for color tone measurement. Furthermore, FIG. 8 also shows the flow rate Q[N2] of nitrogen gas (variation range), the processing temperature (surface temperature of the workpiece 100), and the film formation rate in each film formation process. FIG. 8 also shows the measurement results of the internal stress of each titanium nitride film.

[0087] As shown in Fig. 8, for example, the difference in film thickness was 0.06 µm. This film thickness difference of 0.06 µm is far smaller than the film thickness difference (0.21 µm) in the prior art described above. Furthermore, when this film thickness difference of 0.06 µm is expressed as a ratio to the average film thickness of each titanium nitride film formed by ten film formation processes, it is ±5.36%, which is a level that is fully practical. In other words, it was confirmed that good reproducibility was obtained for film thickness according to this embodiment.

[0088] Focusing on the film formation speed, the difference between the film formation speeds was 0.05 μm / h. This film formation speed difference of 0.05 μm / h is much smaller than the film formation speed difference (0.16 μm / h) by the above-mentioned conventional technology. In addition, when this film formation speed difference of 0.05 μm / h is expressed as a ratio to the average film formation speed in each of the 10 film formation processes, it is ±6.17%, and this ratio of ±6.17% is a sufficiently small value for practical use. In other words, it was confirmed that according to this embodiment, the variation in the film formation speed is sufficiently small, that is, the film formation speed is stabilized.

[0089] Furthermore, when we look at the color tone, the element of the color tone, L* ,a * and b * Each difference ΔL * ,Δa * and Δb * were 0.64, 0.85, and 1.16, which were all less than 2. * ,Δa * and Δb * The value of each difference ΔL * ,Δa * and Δb * These values ​​are much smaller than those of 4.21, 5.77, and 15.70. * ,Δa * and Δb * The L value of each titanium nitride film formed by ten film formation processes was * ,a * and b * When expressed as a ratio to the individual average values, the values ​​are ±0.51%, ±7.25% and ±1.67%, which are at levels sufficient for practical use. In other words, it was confirmed that this example also provides good reproducibility in terms of color tone.

[0090] In addition, when paying attention to the nitrogen gas flow rate Q[N2] (variation range) in each film formation process, the minimum value is about 30 mL / min, specifically 25.8 mL / min to 36.6 mL / min. And the maximum value of the nitrogen gas flow rate Q[N2] is about 40 mL / min, specifically 39.2 mL / min to 43.5 mL / min. Although the variation in this nitrogen gas flow rate Q[N2] seems to be relatively large, it was confirmed that good reproducibility was obtained for the film thickness and color tone as mentioned above.

[0091] Moreover, when looking at the processing temperature in each film formation process, the processing temperature is approximately 240° C., and the difference is 10° C. When this processing temperature difference of 10° C. is expressed as a ratio to the average processing temperature in each film formation process, it is ±2.07%, and this ratio of ±2.07% is an extremely small value. In other words, according to this embodiment, it was confirmed that the variation in processing temperature is sufficiently small.

[0092] Focusing on the internal stress (compressive stress) of the titanium nitride film formed by each film formation process, the internal stress is approximately -7 GPa, with a difference of 1.15 GPa. When this difference of 1.15 GPa is expressed as a ratio to the average internal stress of each titanium nitride film, it is ±8.34, and this ratio of ±8.34% is an extremely small value. In other words, according to this embodiment, it was confirmed that the variation in internal stress is also sufficiently small.

[0093] FIG. 9 shows a list of the control procedures in the titanium nitride film forming process according to this embodiment and the corresponding control procedures according to the above-mentioned prior art.

[0094] As shown in Fig. 9, in the titanium nitride film deposition process according to the above-mentioned conventional technology, 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 is automatically controlled so that the pressure P in the vacuum chamber is kept constant. The arc discharge power Ed is kept constant, the sputtering power Es is kept constant, and the substrate bias voltage Vb (average value) is kept constant. Additionally, the deposition time T is kept constant.

[0095] In contrast to this, in the titanium nitride film deposition process according to this embodiment, the flow rate Q [Ar] of argon gas as the discharge gas is kept constant, and the angle θ of the conductance valve 22 is kept constant. Then, the flow rate Q [N2] of nitrogen gas as the reactive gas is automatically controlled so that the pressure P in the vacuum chamber 12 is kept constant. Then, the arc discharge power Ed is kept constant, the sputtering power Es is kept constant, and further, the substrate bias voltage Vb (average value) is kept constant. Additionally, the deposition time T is kept constant.

[0096] That is, according to the conventional technology, the angle θ of the conductance valve is automatically controlled so that the pressure P in the vacuum chamber is constant while the flow rate Q[N2] of the nitrogen gas is constant. In contrast, according to this embodiment, the flow rate Q[N2] of the nitrogen gas is automatically controlled so that the pressure P in the vacuum chamber 12 is constant while the angle θ of the conductance valve 22 is constant. In these respects, the configurations of this embodiment and the conventional technology are fundamentally different from each other. Due to this difference in configuration, according to this embodiment, a titanium nitride film can be formed with good reproducibility compared to the conventional technology, and in particular, a very beneficial effect is exhibited in that good reproducibility can be obtained for the film thickness and color tone of the titanium nitride film.

[0097] FIG. 10 shows the difference in film thickness, film formation rate, and color tone ΔL * ,Δa * and Δb * 10. As is clear from Fig. 10, according to this embodiment, better reproducibility of film thickness and color tone can be obtained as compared with the conventional technique, and the difference in film formation rate can be suppressed to a value small enough for practical use.

[0098] As described above, according to this embodiment, the sputtering rate is stabilized, which improves 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. Moreover, good reproducibility can be obtained over a long period of time (until the end of the life of the target 242).

[0099] It should be noted that the present 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 be applied to aspects other than the present embodiment.

[0100] For example, as shown in FIG. 11, a plurality of magnetron sputter cathodes 24, 24, ... may be provided, and strictly speaking, a plurality of units 400 including the magnetron sputter cathode 24, that is, four units 400 may be provided. Specifically, each unit 400 includes the magnetron sputter cathode 24, the earth shield 26, and the cathode filament 30. Although not shown in FIG. 1, each unit 400 includes a sputter power supply 28, a heating power supply 32, an arc discharge power supply 34, a current detector 36, and a heating controller 38. That is, each unit 400 is, so to speak, a source of plasma 300, and a plurality of units 400 as the source of plasma 300, that is, four units 400 may be provided. Each of these units 400, 400, ... is provided at equal intervals along the circumferential direction of a circle centered on the central axis Xa of the vacuum chamber 12, that is, at 90 degree intervals here. In addition, each of the units 400, 400, . . . is disposed at the same distance from the central axis Xa of the vacuum chamber 12.

[0101] 11, the film formation speed of the reactive film is improved (faster). Also in the configuration shown in FIG 11, the flow rate Q [N2] of the nitrogen gas is automatically controlled so that the pressure P in the vacuum chamber 12 is constant, thereby improving the reproducibility of the reactive film. Moreover, the elements responsible for the automatic control, that is, the pressure gauge 62, the gas flow controller 64, and the mass flow controller 60b for introducing the reactive gas, do not need to be provided in multiples, and only one common to each unit 400, 400, ... is sufficient.

[0102] The number of units 400 is not limited to four. In any case, it is essential that the units 400, 400, ... are provided at equal intervals along the circumferential direction of a circle centered on the central axis Xa of the vacuum chamber 12 and are provided at the same distance from the central axis Xa of the vacuum chamber 12.

[0103] In this embodiment, the case where a titanium nitride film is formed as a reaction film has been described, but the present invention can also be applied to the case where various reaction films such as nitride films, carbonitride films, and carbide films other than the titanium nitride film are formed. 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 (Y2O3) film. In this case, a target 242 made of a material according to the type of reaction film is used. When a carbonitride film is formed, a hydrocarbon gas such as acetylene (C2H2) gas is used as the reaction gas in addition to nitrogen gas. When a carbonized film is formed, a hydrocarbon gas such as acetylene is used as the reaction gas instead of nitrogen gas. When an insulating reaction film such as an aluminum nitride film or a silicon nitride film is formed, a pulse power supply device that outputs bipolar pulse power similar to the bias power supply device 50 is used as the sputtering power supply device 28 instead of a DC power supply device.

[0104] In addition, in practice, before forming the reaction film, a film forming process is performed to form an intermediate layer to improve the adhesion of the reaction film. For example, when the reaction film is a titanium nitride film, a titanium (Ti) film is formed as the intermediate layer, and the intermediate layer is appropriately selected depending on the type of the reaction film.

[0105] Furthermore, in this embodiment, a pulse power supply device is used as the bias power supply device 50, but this is not limited thereto. 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 device may be used. 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 use a pulse power supply device or a high-frequency power supply device as the bias power supply device 50. Also, if the workpiece 100 is an insulating material, a high-frequency power supply device is used as the bias power supply device 50.

[0106] The present invention is not limited to application to the magnetron sputtering apparatus 10, but can also be applied to a film forming method using the magnetron sputtering method. [Explanation of symbols]

[0107] 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 … Gas flow controller 100 … Processing object 242 … Target 300... Plasma 400 … units

Claims

1. A film forming apparatus for forming a reaction film on a workpiece by magnetron sputtering, a vacuum chamber which is at ground potential and in which the workpiece is accommodated; 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 to surround the outer periphery of the magnetron sputtering cathode while exposing the sputtering surface in order to limit a 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 for discharging particles of the inert gas to the earth shield and the magnetron sputtering cathode, the earth shield being an anode and the magnetron sputtering cathode being a cathode; A reactive gas introduction means for introducing a reactive gas, which is a material for the reactive film, into the vacuum chamber; a bias power supply means for supplying a bias power having a constant predetermined component to the vacuum chamber and the workpiece, the bias power being used to accelerate the inert gas particles, the reactive gas particles, and the sputtered particles sputtered from the sputtering surface of the target toward the workpiece, with the vacuum chamber as an anode and the workpiece as a cathode; 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 for heating the cathode filament to emit thermoelectrons from the cathode filament; an arc discharge power supply means for supplying arc discharge power to the earth shield and the cathode filament, with the earth shield serving as an anode and the cathode filament serving as a cathode, for accelerating the thermoelectrons toward the earth shield; a heating power control means for controlling the heating power so that a current component of the arc discharge power is constant while a voltage component of the arc discharge power is constant; and a reactive gas flow rate control means for controlling a flow rate of the reactive gas into the vacuum chamber so that a pressure inside the vacuum chamber is constant while the sputtering power is kept constant and the effective exhaust speed is kept constant by the conductance valve.

2. 2. The film forming apparatus according to claim 1, comprising a plurality of units each including the magnetron sputtering cathode, the earth shield, the sputtering power supply means, the cathode filament, the heating power supply means, the arc discharge power supply means, and the heating power control means.

3. 3. The film forming apparatus according to claim 1, wherein the bias power is a direct current power, an asymmetric bipolar pulse power, or a high frequency power.

4. A film formation method for forming a reaction film on a workpiece by magnetron sputtering, comprising the steps of: a step of placing the workpiece in a vacuum chamber having a magnetron sputtering cathode at ground potential and having a target that is to be the material of the reaction film, the workpiece being placed in such a way 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, the earth shield being set to a ground potential and being provided so as to surround the outer periphery of the magnetron sputtering cathode with the sputtering surface exposed in order to limit the sputtering area of ​​the magnetron sputtering cathode to the sputtering surface, as an anode and the magnetron sputtering cathode being a cathode; a reactive gas introduction step of introducing a reactive gas, which is a material for the reactive film, into the vacuum chamber; a bias power supply step of 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 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 as an anode and the cathode filament as a cathode, for accelerating the thermoelectrons toward the earth shield; a heating power control step of controlling the heating power so that a current component of the arc discharge power is constant while a voltage component of the arc discharge power is constant; and a reactive gas flow rate control step of controlling a flow rate of the reactive gas into the vacuum chamber so that a pressure inside the vacuum chamber is constant while the sputtering power is kept constant and the effective exhaust speed is kept constant by the conductance valve.

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