JP2017174514A - Arc type evaporation source, film forming device, and method of manufacturing film forming body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose an arc type evaporation source capable of performing arc discharge by suppressing occurrence of droplets without using a filter for removing the droplets, and also to provide a film forming device and a method of manufacturing a film forming body.SOLUTION: An arc type evaporation source 20 includes: an axisymmetric cylindrical magnetic field forming mechanism 116 which houses a cathode 22 therein and forms magnetic field in the direction parallel to a center axis of the cathode 22 in the vicinity of an evaporation surface 23 of the tip of the cathode 22; an advancing/retreating mechanism 38 for advancing/retreating the cathode 22 in the axial direction; and a pulse discharge current power source 14 for flowing a pulse current into the cathode 22. The cathode 22 has the length in the axial direction which is longer than the diameter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an arc evaporation source, a film forming apparatus, and a method for manufacturing a film forming body.

  Form a film on the outer surface of the substrate to improve wear resistance and durability, reduce friction loss, and protect the surface shape and add color to the cathode material using arc discharge An arc evaporation source that melts and evaporates is used.

  In the arc evaporation source, most of the material constituting the evaporated cathode is ionized by arc discharge plasma formed in the space in front of the cathode evaporation surface by arc discharge. Then, by applying a predetermined voltage to the substrate to be deposited using the formed arc discharge plasma, the ionized cathode material is attracted to the substrate to form a deposited body on the surface of the substrate.

  The arc ion plating method (see, for example, Patent Document 1), which is a film formation method using the arc evaporation source, has a high film formation speed and excellent adhesion between the film formation body and the substrate. A film forming apparatus by this method is excellent in productivity, and is widely used as an apparatus for forming a film formed of a metal film, its carbide, nitride or the like on the surface of a base material part, a cutting tool or the like.

  In order to improve the durability of the film formation body, in addition to improving the film quality, particularly the wear resistance, increasing the film thickness is one of the methods. However, in the arc ion plating method, molten particles of the cathode constituent material, so-called droplets, are released from the cathode evaporation surface along with the arc discharge. This droplet is taken into the film forming body to be formed, and when the surface roughness increases or defects such as voids are formed in the film forming body, the mechanical strength of the film forming body decreases. There is.

  And as the film thickness increases, the amount of droplets taken into the film-forming body increases and the smoothness of the film decreases, and the smoothing process is not easy. Or form. And it becomes a factor which reduces the external appearance quality of a film-forming body.

  In the arc ion plating method, a filtered cathodic arc ion plating method is known as a method for reducing the amount and size of droplets taken into a film-formed body (see, for example, Patent Document 2). In the filtered cathodic arc ion plating method, a bent magnetic coil is placed between a cathode and a substrate to be deposited, and electrons, ions, etc. in the arc discharge plasma are aligned along the lines of magnetic force formed by the magnetic coil. In this film forming method, the trajectory of charged particles is bent to separate droplets that go straight without being affected by a magnetic field because they have no charge or have a small specific charge.

JP-A-8-199346 Japanese Patent Laid-Open No. 11-335837

  However, in the filtered cathodic arc ion plating method, it is difficult to transport all charged particles to the film formation substrate. This is because ions in the arc discharge plasma move circularly under the influence of the magnetic field, but ions with kinetic energy whose radius of motion (Larmor radius) is larger than the internal space of the magnetic coil It is because it collides with. As a result, such ions cannot contribute to the formation of the film formation body, and the film formation speed becomes slow.

  In the film forming apparatus, a filter is added to the arc evaporation source. This filter is equipped with a magnetic coil, and its weight is heavy. And the vacuum vessel wall surface provided with the evaporation source installation port of the film forming apparatus for forming the film forming body by the filtered cathodic arc ion plating method needs to have a high load resistance, and the weight of the vacuum vessel becomes heavy. For these reasons, the cost of the film forming apparatus increases.

  Thus, there is a demand for development of a method capable of suppressing arc formation and performing arc discharge without using a filter for removing droplets.

  Therefore, an object of the present invention is to propose an arc evaporation source, a film forming apparatus, and a method for manufacturing a film forming body capable of suppressing arc generation and performing arc discharge without using a filter for removing the droplets. There is to do.

  An arc evaporation source according to the present invention that solves the above-described problems is an arc evaporation source that heats a cathode by arc discharge to evaporate a material constituting the cathode, and accommodates the cathode, and an evaporation surface at the tip of the cathode An axially symmetric cylindrical magnetic field forming mechanism for forming a magnetic field in a direction parallel to the central axis of the cathode, a cathode advance / retreat mechanism for sending the cathode in the axial direction, and a pulse discharge current power source for supplying a pulse current to the cathode The cathode has an axial length longer than a diameter.

  The arc discharge moves under the influence of the magnetic field around the arc spot where the arc discharge is maintained, but the cathode evaporation surface is consumed and the cathode evaporation surface recedes with the arc discharge. As a result, since the positional relationship between the magnetic field formation mechanism and the cathode evaporation surface changes with time, the movement of the arc spot also changes. In the arc evaporation source of the present invention, an axially symmetric cylindrical magnetic field forming mechanism, a cathode disposed inside the axial magnetic field forming mechanism, and a cathode advance / retreat mechanism for moving back and forth in the axial direction of the magnetic field forming mechanism are combined. As a result, the cathode can be advanced and retracted according to the consumption of the cathode, the magnetic field configuration in the vicinity of the cathode evaporation surface where the arc spot moves can be kept constant, and the arc discharge is stably maintained.

  Further, since the cathode has a length in the axial direction that is long with respect to the diameter, it is possible to continue supplying the film-forming substance even in film formation with a film thickness of 5 μm or more and a long discharge time. Of course, it goes without saying that a film-formed body can be formed using the arc evaporation source of the present invention even when the film thickness is less than 5 μm.

  The magnetic field formation mechanism preferably has rotational symmetry. As this magnetic field forming mechanism, for example, a cylindrical permanent magnet or a permanent magnet in which different magnetic poles are arranged in the axial direction are arranged in a cylindrical shape, or an electromagnet having a cylindrical iron core and a coil, for example, for a general structure An electromagnet having a magnetic coil arranged on the outer periphery of a ferromagnetic cylinder such as the rolled steel SS400 can be used.

  The film forming apparatus of the present invention is characterized by comprising the arc evaporation source of the present invention. With the film formation apparatus of the present invention, the amount of droplets taken into the film can be suppressed, and a film formation with a small surface roughness can be formed.

  Furthermore, the manufacturing method of the film-forming body of the present invention is a method of manufacturing a film-forming body that forms the film-forming body on the surface of the substrate using the film-forming apparatus of the present invention, and the frequency of the pulse discharge current power source. Is 50 Hz or more and 1000 Hz or less.

  In order to maintain the arc discharge stably, it is necessary to stably maintain the thermal electron emission at the arc spot. For this reason, the cathode evaporation surface in the vicinity of the arc spot must be given a certain heat load, and the arc discharge can be maintained by setting the frequency of the pulse discharge current power source to 50 Hz or more and 1000 Hz or less. It becomes. Preferably, the frequency is 100 Hz or more and 500 Hz or less.

  In the method for producing a film-formed body of the present invention, the value of the pulse discharge current is preferably 40 A or more and 300 A or less, the base current of the arc discharge current is 8 A or more and 20 A or less, or 8 A or more and the pulse discharge current is 0.3. It is preferable to make it not more than twice.

Furthermore, in the method for manufacturing a film-forming body of the present invention, the pulse width T _ON of the pulse discharge current is preferably 0.3 msec or more, and the ratio of the pulse width T _ON to the period T of the pulse discharge current D = T _ON / T is preferably 0.45 or less.

  Furthermore, in the method for manufacturing a film formation body according to the present invention, it is preferable to form the film formation body with a thickness of 5 μm or more.

  According to the arc evaporation source of the present invention, it is possible to perform arc discharge while suppressing generation of droplets without using a filter for removing droplets.

It is a schematic diagram of an example of the arc evaporation source of the present invention. It is the schematic of an example of the film-forming apparatus provided with the arc type evaporation source of this invention. It is a figure which shows the outline | summary of the time change of the arc discharge current which flows into the cathode of the arc type evaporation source of this invention. It is a figure which shows another example of the arc type evaporation source of this invention.

  Hereinafter, preferred embodiments of the arc evaporation source of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic view showing an example of an arc evaporation source of the present invention. An arc evaporation source 20 shown in this figure is installed on an opening flange 4a of a vacuum chamber 4 (only a part of the vacuum chamber wall is shown in the figure) via an insulator 46, and constitutes an arc type film forming apparatus as a whole. doing.

  The arc evaporation source 20 includes a magnetic field forming mechanism 116, a cathode holding flange 29 that holds the cathode 22, a cathode advance / retreat mechanism 38, and a pulse discharge current power source 14.

  The magnetic field forming mechanism 116 accommodates the cathode 22 and forms a magnetic field in a direction parallel to the central axis of the cathode 22 or a magnetic field spreading in a direction away from the central axis near the evaporation surface 23 at the tip of the cathode 22. In the present embodiment, the magnetic field forming mechanism 116 is “cylindrical”. However, the present invention is not limited to this, and if it is cylindrical, for example, a bar magnet having the same magnetic pole arrangement direction is cylindrical. It may be arranged in the form.

  Further, the magnetic field forming mechanism 116 does not need to be configured by a magnet. For example, a coil is formed so as to surround a cylindrical ferromagnetic body manufactured by SS400 (JIS G 3101: 2004 “General Structure Rolled Steel”). It may be an electromagnet or a coil. Furthermore, you may be comprised by the combination of the magnet and the ferromagnetic material.

  The cathode 22 has an axial length that is longer than the diameter. Thereby, a thick film-forming body of 5 μm or more can be formed. The diameter of the cathode 22 is, for example, 20 mm or more and 80 mm or less. Moreover, the length of the cathode 22 is, for example, 1.5 times the diameter or 50 mm or more, whichever is longer, and 400 mm or less.

  Further, as the material of the cathode 22, a conductive material that is not a ferromagnetic material can be used. For example, a cylindrical and solid material can be used. When a non-ferromagnetic material is used, even if the position and length of the evaporation surface 23 of the cathode 22 change, the magnetic field configuration by the magnetic field forming mechanism 116 is not affected. Examples of the material include metals other than ferromagnetic materials such as Fe, alloys having no ferromagnetism such as SUS304, metalloid materials such as carbon, and semiconductor materials such as InAs. In particular, it is preferable to use a material composed of one or more of non-ferromagnetic metals and metal carbides, metal nitrides, metal borides, and metal sulfides. Examples of such metals include Ti, V, Cr, Al, Nb, Zr, Mo, W, Hf, Ta can be mentioned.

  The shape of the cathode 22 is not limited, and may be a polygonal columnar shape in addition to the above-described columnar shape. In this case, the diameter of the cathode 22 means the diameter of a circle passing through all the vertices of the polygon. The cross-sectional shape of the cylinder of the magnetic field forming mechanism 116 and the cross-sectional shape of the cathode 22 may be similar or different, but usually the cross-sectional shapes of both are similar in view of the symmetry of the magnetic field to be formed ( For example, when the magnetic field forming mechanism 116 is a cylinder, the cathode 22 is also preferably a column).

  The cathode 22 and the cathode holding flange 29 are electrically connected. Further, between the cathode holding flange 29 and the ground 2, a pulse discharge current power source 14 for supplying a pulse current to the cathode 22 is connected. By adjusting the frequency and pulse width of the pulse current generated by the pulse discharge current power supply 14, excessive heating of the cathode evaporation surface 23 in the vicinity of the arc spot for maintaining the arc discharge is suppressed, and the generation of droplets is reduced. be able to.

  An arc discharge is generated between the cathode 22 and the anode (which is grounded) or the shield plate 10 (which is grounded via the resistor 60) in the vacuum chamber 4 by the pulse discharge current power source 14. As a result, the ionized cathode constituent material 24 jumps out from the arc spot 62 on the evaporation surface 23, and a film forming body is formed on the surface of the film forming substrate (not shown) in the vacuum chamber 4. In addition, the code | symbol 24 in FIG. 1 has shown the flow of cathode constituent materials 24, such as the ion discharge | released from the evaporation surface 23 by arc discharge.

  The cathode 22 is attached to a cathode advance / retreat mechanism 38 via a cathode holding flange 29, and the cathode holding flange 29 and the cathode 22 move in the magnetic field forming mechanism 116 in the axial direction in accordance with the advance / retreat of the cathode advance / retreat mechanism 38. Advance and retreat. The cathode advance / retreat mechanism 38 can be constituted by a stepping motor, for example.

  The cathode evaporation surface 23 retreats because the cathode 22 is consumed over time of arc discharge. If arc discharge is continued in this state, the shield plate 10, the vacuum chamber 4 and the like will eventually melt. In order to avoid this, it is necessary to send out the cathode 22 according to the consumption of the cathode 22. For example, the consumption state of the cathode 22 is determined by contacting the trigger 16 with the cathode evaporation surface 23 to detect the position of the tip of the trigger 16 and the consumption amount of the cathode 22 corresponding to discharge conditions such as arc discharge current. For example, the position of the cathode evaporation surface 23 is detected or estimated, and the cathode advance / retreat mechanism 38 is operated to advance / retreat the cathode 22. Thereby, the magnetic field configuration in the vicinity of the cathode evaporation surface 23 where the arc spot moves can be kept constant, and the arc discharge can be stably maintained.

(Deposition system)
Next, the film forming apparatus of the present invention will be described. The film forming apparatus of the present invention is characterized by including the above-described arc evaporation source of the present invention, and other configurations are not limited. FIG. 2 is a schematic view of an example of a film forming apparatus including the arc evaporation source of the present invention. The film forming apparatus 200 shown in this figure includes a vacuum chamber 4, an arc evaporation source 20, a process gas introduction system 82 for introducing a process gas into the vacuum chamber 4, and a turntable for rotating a film forming substrate. 120 and a rotation shaft 112 for fixing the film formation substrate.

  Since the film forming apparatus 200 of the present invention can suppress droplets emitted from the cathode 20 of the arc evaporation source 20, the amount of droplets taken into the film forming body can be reduced and smooth film formation can be achieved. The body can be formed.

(Method for producing film-formed body)
Subsequently, a preferred embodiment of the method for producing a film-forming body of the present invention will be described with reference to the drawings. In manufacturing a film-forming body by the arc ion plating method using arc discharge, in order to reduce droplets taken into the film-forming body to be formed, to the cathode evaporation surface 23 in the vicinity of the arc spot for maintaining the arc discharge. It is indispensable to suppress excessive heating of the trigger 16 and to reduce the frequency of operation of the trigger 16 that is operated when starting arc discharge, and it is necessary to stably maintain pulse arc discharge.

  FIG. 3 shows an outline of the time change of the current flowing from the pulse discharge current power source 14 that performs arc discharge. Here, the arc discharge current flows from the cathode 22 to the ground 2 via the pulse discharge current power source 14. In FIG. 3, the current value flowing in this direction is a positive value.

In the arc discharge, the tip of the trigger 16 is brought into contact with the cathode evaporation surface 23 to flow an electric current to locally heat the evaporation surface 23. Then, by quickly separating the trigger 16 from the evaporation surface 23, thermoelectrons are emitted from the heating portion (arc spot 62), and arc discharge is started. For the heating, a constant current needs to flow, and at least the trigger 16 and the evaporation surface 23 need to be in contact with each other for a time T _ON or longer.

Release of the cathode structure material 24 by arc discharge is made mainly by the discharge current between the T _ON. This discharge current also plays a role of heating so that the emission of thermoelectrons at the arc spot 62 required for maintaining the arc discharge is stably maintained. For this purpose, the discharge current is preferably 40 A or more. More preferably, it is 60 A or more. Further, the discharge current is preferably 300 A or less. When the discharge current exceeds 300 A, the cathode evaporation surface 23 in the vicinity of the arc spot 62 during T _OFF is not sufficiently cooled, and the effect of suppressing the generation of droplets is reduced. More preferably, the film forming body is formed with a discharge current of 240 A or less.

The main role of the base current is to suppress an excessive temperature drop while cooling the arc spot 62 during T _OFF and maintain it at a temperature at which thermionic emission is possible. For this purpose, the base current is preferably 8 A or more. On the other hand, the base current is preferably 20 A or 0.3 times or less of the discharge current. In a film formation body formed with a base current exceeding this range, the amount of droplets taken into the film formation body and the effect of reducing the size cannot be obtained, and the surface roughness of the film formation body increases. .

The film-formed body is formed at a frequency of the pulse discharge current of 50 Hz to 1000 Hz. When the frequency is lower than 50 Hz, the times T _ON and T _OFF become longer, and the temperature change of the arc spot 62 is too large. Along with this, it becomes difficult to emit thermoelectrons, and arc discharge cannot be started, or the amount of generated droplets increases. As a result, the amount of droplets taken into the film formation body increases, for example, the operation frequency of the trigger 16 increases, and the surface roughness of the film formation body increases. On the other hand, when the frequency exceeds 1000 Hz, the time of T _ON and T _OFF is shortened, and the temperature change of the cathode evaporation surface 23 in the vicinity of the arc spot 62 hardly occurs. Therefore, the difference from the case of direct current discharge with a discharge current that reaches the time average value of the discharge current is small, and the superiority of the film formation by pulse discharge is reduced. The frequency of the pulse discharge current is preferably 100 Hz or more and 500 Hz or less.

The pulse width T _ON of the pulse discharge current is preferably 0.3 msec or more. If the pulse width T _ON is less than 0.3 msec, the cathode evaporation surface 23 in the vicinity of the arc spot 62 cannot be sufficiently heated, so that it is difficult to emit thermoelectrons to maintain the arc discharge, and the arc discharge cannot be started. It may be difficult to stably maintain the arc discharge. As a result, the formation of the film formation itself becomes difficult, the operation frequency of the trigger 16 increases, the amount of droplets taken into the film formation increases, and the surface roughness of the film formation increases. To do.

Further, the ratio D of the pulse width T _ON of the discharge current to the cycle T of the pulse discharge current is D = T _ON /T≦0.45
It is preferable to form the film-forming body under discharge conditions that satisfy the above. When the ratio D exceeds 0.45, the amount of droplets taken into the film formation body increases, and the surface roughness of the film formation body increases.

The pulse current waveform of the arc discharge current is not limited to the rectangular wave shown in FIG. 3, and may be a sine wave pulse, a trapezoidal wave pulse, or a triangular wave pulse. In this case, the pulse width T _ON of the discharge current is a time width at half the peak current value. Further, when the discharge current during the time T _ON changes with time, the time average value of the discharge current during this time is set as the value of the pulse discharge current. Similarly, when the discharge current during the time T _OFF changes with time, the time average value of the discharge current during this time is set as the base current value.

  Hereinafter, the present invention will be described in more detail in the following examples, but the present invention is not limited to the examples.

(Example 1-1)
The carbon film-forming body was formed using the film-forming apparatus 200 shown in FIG. 2 provided with the arc type evaporation source 20 shown in FIG. A mirror-polished high-speed tool steel (SKH51 material, surface roughness Ra: 0.025 μm or less) is used as a film-forming substrate, and this is a rotating shaft attached to the turntable 120 of the film-forming apparatus 200. Fixed to 112 surface.

  As the cathode 22, a cylindrical graphite cathode (carbon purity: 98% or more) having an outer diameter of 50 mm and an axial length of 200 mm was used. Further, as the magnetic field forming mechanism 116, a neodymium magnet having a diameter of 8 mm and a length of 30 mm arranged uniformly in a cylindrical shape was used. The inner diameter of this magnet is 64 mm.

Prior to film formation, vacuum evacuation was performed for ion bombardment. In this ion bombardment process, first, the inside of the vacuum chamber 4 was evacuated to 1 × 10 ⁻³ Pa or less by a vacuum exhaust pump (not shown). At this time, in order to promote gas emission from the inner wall of the vacuum chamber 4 or the like, heating was performed using a heater (not shown). However, the temperature and the treatment time were adjusted so that the film formation substrate was not heated to 200 ° C. or higher.

  After the evacuation, Ar gas was introduced into the vacuum chamber 4 by the process gas introduction system 82, and the Ar gas flow rate was adjusted and maintained so that the pressure in the vacuum chamber 4 was 2 Pa. Then, a pulse bias power source as the pulse discharge current power source 14 connected to the turntable 120 to which the film formation substrate is attached applies a pulse bias (square wave -200 V, frequency 200 Hz) to the cathode 22 for 10 minutes, thereby generating high frequency plasma. Discharge was performed. At that time, Ar ions generated by the discharge are accelerated when a negative bias of a pulse bias is applied, and the surface of the substrate to be deposited is sputtered to clean the surface of the substrate.

  Subsequent to the ion bombardment process, an intermediate layer formation process was performed. In this intermediate layer forming process, a plasma source 130 (sputter source) with a Cr cathode attached was used, and a Cr intermediate layer having a thickness of 0.2 μm was formed on the surface of the substrate to be deposited by sputtering.

Subsequent to the intermediate layer forming process, a carbon film forming process was performed. Specifically, first, Ar gas was introduced into the vacuum chamber 4 by the process gas introduction system 82, and the flow rate of Ar gas to be introduced was adjusted so that the pressure in the vacuum chamber 4 became 3 × 10 ⁻³ Pa. . The graphite cathode 22 performed arc discharge under the conditions shown in Table 1, and at the same time, a DC voltage of −80 V was applied to the turntable 120 to which the film-forming substrate was fixed. While maintaining this state, a film was formed for a predetermined time, and a carbon film having a thickness of 6.0 μm was formed on the surface of the substrate.

(Example 1-2 to Example 1-7, Comparative Example 1-1, Comparative Example 1-2)
In the same manner as in Example 1-1, a carbon film having a thickness of 6.0 μm was formed on the film formation substrate. However, the frequency of the pulse discharge current was changed to the conditions shown in Table 2. Other conditions are the same as in Example 1-1.

(Comparative Example 1-3)
By changing the pulse bias power source as the pulse discharge current power source 14 in the film forming apparatus 200 to a DC current power source and operating the trigger every 6 seconds, the discharge current is controlled to be discharged at 120 A for 2 seconds to obtain a thickness of 7 A carbon film having a thickness of 0.0 μm was formed. The ratio D under this condition is 0.33, and arc discharge becomes intermittent discharge, so the base current is 0A. Other conditions are the same as in Example 1-1.

(Comparative Example 1-4)
A carbon film-forming body was formed under the same conditions as in Comparative Example 1-3 except that the discharge current was changed to 53A.

<Measurement of surface roughness>
Using a stylus type surface roughness measuring instrument (manufactured by Tokyo Seimitsu Co., Ltd., model number: SURFCOM 1400D), according to JIS-B0601 (2001), ten-point average roughness for each surface of the film-formed body after forming the film-formed body R _zjis was measured. This measurement was performed 10 times at different positions, and the average value of the ten-point average roughness R _zjis was obtained. The average values obtained are shown in Table 2. In addition, the average value of 10-point average roughness R _zjis in Table 2 indicates a relative value when the average value of 10-point average roughness R _{zjis in} Comparative Example 1-3 is 1.

As is apparent from Table 2, in each example, a smooth carbon film was formed as compared with Comparative Example 1-3 in which the frequency of the pulse discharge current was low. In particular, in Example 1-1, Example 1-2, Example 1-4, and Example 1-5 in which the film-formed body was formed under the condition where the frequency of the discharge current was 100 Hz to 500 Hz, the ten-point average roughness The average value of the thickness R _zjis was further smaller, and the smoothness of the film-formed body was even better.

On the other hand, Comparative Example 1-1 in which the frequency of the discharge current is lower than 50 Hz, and Comparative Example 1-2 in which the frequency of the discharge current is higher than 1000 Hz have an average value of the ten-point average roughness R _zjis lower than that in Comparative Example 1-3. Although a relatively smooth film was formed, the surface roughness was comparable to that of Comparative Example 1-4 in which a film was formed by direct current discharge at the same discharge current value as the average discharge current. In addition, the superiority of film formation by pulse discharge was not recognized.

(Example 2-1)
A titanium nitride film was manufactured using the film forming apparatus 200 shown in FIG. 2 equipped with the arc evaporation source 20 shown in FIG. A mirror-finished cemented carbide material (surface roughness Ra: 0.025 μm or less) is used as the film forming substrate, and this is applied to the surface of the rotating shaft 112 attached to the turntable 120 of the film forming apparatus 200. Fixed.

  As the cathode 22, a cylindrical titanium cathode (Ti purity: 99% or more) having an outer diameter of 50 mm and an axial length of 90 mm was used. Further, as the magnetic field forming mechanism 116, an electromagnet having a coil arranged on the outer periphery of a general structural rolled steel SS400 having an inner diameter of 64 mm, an outer diameter of 86 mm, and a length of 150 mm was used.

Prior to film formation, vacuum evacuation was performed for ion bombardment. In this ion bombardment process, first, the inside of the vacuum chamber 4 was evacuated to 1 × 10 ⁻³ Pa or less by a vacuum exhaust pump (not shown). At this time, in order to promote gas emission from the inner wall of the vacuum chamber 4 or the like, heating was performed using a heater (not shown). However, the temperature and the treatment time were adjusted so that the film formation substrate was not heated to 200 ° C. or higher.

After evacuation, N ₂ gas is introduced into the vacuum chamber 4 by the process gas introduction system 82, and the flow rate of the N ₂ gas is adjusted and maintained so that the pressure in the vacuum chamber 4 becomes 1.2 Pa. did. Then, using a plasma source 130 (arc evaporation source) with a titanium cathode (Ti purity: 99% or more), arc discharge is performed at a direct current of 60 A, and at the same time a turntable with a film-forming substrate attached A bias voltage of −500 V was applied for 2 minutes by the bias power source connected to 120 to perform ion bombardment. At that time, Ti ions generated by arc discharge are accelerated by applying a negative bias to sputter the surface of the substrate, and the surface of the substrate is cleaned.

After the ion bombardment process, a titanium nitride film was formed. Specifically, by increasing the flow rate of N ₂ gas by the process gas introduction system 82, the pressure in the vacuum chamber 4 is such that 2.6 Pa, and adjusting the flow rate of N ₂ gas to be introduced. The cathode 22 made of titanium was subjected to arc discharge under the conditions shown in Table 3, and at the same time, a DC voltage of −30 V was applied to the turntable 120 to which the film-forming substrate was fixed. While maintaining this state, film formation was performed for a predetermined time, and a titanium nitride film-forming body having a thickness of 12.0 μm was formed on the surface of the base material. The film formed body thus formed was designated as Sample 2-1a.

  Next, a titanium nitride film-forming body having a thickness of 12.0 μm serving as a roughness reference when formed with the same discharge current was formed. The discharge current source connected to the arc evaporation source was changed to a direct current power source, and the trigger was operated every 6 seconds, thereby controlling the discharge current at 200 A for 1 second. Therefore, the discharge frequency is 0.167 Hz and the ratio D is 0.167. Since the arc discharge is intermittent discharge, the base current is 0A. The film formation substrate on which the film formation body was thus formed was designated as Sample 2-1b.

<Measurement of surface roughness>
About the sample 2-1a and the sample 2-1b obtained as described above, a stylus type surface roughness measuring device (manufactured by Tokyo Seimitsu Co., Ltd., model number: SURFCOM 1400D) was used according to JIS-B0601 (2001). Ten-point average roughness R _zjis was measured for each surface of the film body. This measurement was measured 10 times at different positions, and an average value was obtained. The average values of the ten-point average roughness R _zjis obtained for Sample 2-1a and Sample 2-1b are R _zjis (2-1a) and R _zjis (2-1b), respectively, and R _zjis (2-1a) The ratio R of R _zjis ( _2-1b ) was calculated. This ratio R is an index representing the reduction rate of the surface roughness under the same pulse discharge current. The resulting ratio R is shown in Table 4.

<Determination of discharge stability>
In the titanium nitride film forming process, when the pulse arc discharge is stopped and the frequency of restarting the discharge by operating the trigger is 1 time / minute or less, it is determined as “◯”, and the frequency is 1 time / time. When it exceeded the minute, it determined with "x". Table 4 shows the obtained results.

(Example 2-2 to Example 2-6, Comparative Example 2-1 to Comparative Example 2-4)
In the same manner as in Example 2-1, a 12.0 μm-thick titanium nitride film was formed on the film formation substrate. However, the pulse discharge current and the base current were changed to the conditions shown in Table 4. Other conditions are all the same as in Example 2-1. The resulting ratio R is shown in Table 4.

  As is clear from Table 4, in each example, a smooth titanium nitride film was formed by setting the pulse discharge current to 40 A or more and 300 A or less. In particular, in Example 2-1 to Example 2-3, Example 2-5, and Example 2-6 in which the film formation was formed under a condition where the pulse discharge current was 40 A or more and 240 A or less, the surface of the film formation was smooth. The properties were even better.

  On the other hand, in Comparative Example 2-1 in which the pulse discharge current exceeds 300 A, Comparative Example 2-3 in which the base current is less than 8 A, and Comparative Example 2-4 in which the ratio R of the pulse discharge current to the base current is 0.35 or more The ratio R, which is an index representing the reduction rate of the surface roughness, was close to 1, and no effect was obtained by using pulse discharge. Furthermore, in Comparative Example 2-3, the discharge frequently stopped during the discharge. In Comparative Example 2-2 in which the pulse discharge current is less than 40 A, the discharge could not be started and a chromium nitride film could not be formed.

(Example 3-1)
In the film forming apparatus 200 shown in FIG. 2, a chromium nitride film was formed using an arc evaporation source 21 shown in FIG. 4 instead of the arc evaporation source 20 shown in FIG. A mirror-finished cemented carbide material (surface roughness Ra: 0.025 μm or less) is used as the film forming substrate, and this is applied to the surface of the rotating shaft 112 attached to the turntable 120 of the film forming apparatus 200. Fixed.

  As the cathode 22, a cylindrical chromium cathode (Cr purity: 99% or more) having an outer diameter of 50 mm and an axial length of 150 mm was used. Further, a magnetic coil is used for the magnetic field forming mechanism 42, and a magnetic field of 60 mT is formed at the center of the evaporation surface (tip portion on the film forming chamber side) of the cathode made of chromium by the excitation power supply 44 connected to the magnetic field forming mechanism 42. Configured.

Prior to film formation, vacuum evacuation was performed for ion bombardment. In this ion bombardment process, first, the inside of the vacuum chamber 4 was evacuated to 1 × 10 ⁻³ Pa or less by a vacuum exhaust pump (not shown). At this time, in order to promote gas emission from the inner wall of the vacuum chamber 4 or the like, heating was performed using a heater (not shown). However, the temperature and the treatment time were adjusted so that the film formation substrate was not heated to 200 ° C. or higher.

After the evacuation, the process gas introduction system 82 introduces N ₂ gas into the vacuum chamber 4 and adjusts the flow rate of the N ₂ gas so that the pressure in the vacuum chamber 4 becomes 1.2 Pa. Maintained. Then, using a plasma source 130 (arc-type evaporation source) with a chromium cathode (Cr purity: 99% or more), arc discharge is performed with a direct current of 80 A, and at the same time, a turntable with a film-forming substrate attached A bias power source 14 connected to 120 was applied with a bias voltage of −600 V for 1.7 minutes to perform ion bombardment. At that time, Cr ions generated by the arc discharge are accelerated by applying a negative bias to sputter the surface of the substrate, and the surface of the substrate is cleaned.

Subsequent to the ion bombardment, a chromium nitride film was formed. Specifically, by increasing the flow rate of N ₂ gas by the process gas introduction system 82, the pressure in the vacuum chamber 4 is such that 2.7 Pa, and adjusting the flow rate of N ₂ gas to be introduced. The cathode 22 made of chromium was subjected to arc discharge under the conditions shown in Tables 5 and 6, and at the same time, a DC voltage of −3 V was applied to the turntable 120 to which the film-forming substrate was fixed. While maintaining this state, a film was formed for a predetermined time to form a chromium nitride film-forming body having a thickness of 28.0 μm on the surface of the substrate.

(Example 3-2 to Comparative Example 3-7, Comparative Example 3-1 to Comparative Example 3-3)
Similarly to Example 3-1, a chromium nitride film-forming body having a thickness of 28.0 μm was formed on the film-forming substrate. However, the discharge current frequency and pulse width T _ON were changed to the conditions shown in Table 6. The other conditions are all the same as in Example 3-1.

<Measurement of surface roughness>
Using a stylus type surface roughness measuring instrument (manufactured by Tokyo Seimitsu Co., Ltd., model number: SURFCOM 1400D), according to JIS-B0601 (2001), the ten-point average roughness R _{zjis with} respect to the film-formed body surface after film formation. Were measured 10 times at different positions, and the average value was obtained. The average values obtained are shown in Table 6. Note that the average value of the point average roughness R _zjis in Table 6 indicates a relative value when the average value of the ten-point average roughness R _zjis of Comparative Example 3-1 is 1.

As can be seen from Table 6, in each example, a smooth chromium nitride film was formed under a pulse width condition satisfying the condition that the pulse width T _ON was 0.3 ms or more and the ratio D was 0.45 or less. Is formed. In particular, in Example 3-1 to Example 3-2 and Example 3-4 to Example 3-7 in which the film formation was formed under the condition where the ratio D was less than 0.41, the smoothness of the film formation was It was even better.

On the other hand, in Comparative Example 3-1 and Comparative Example 3-2 in which the ratio D exceeds 0.45, the value of the ten-point average roughness R _zjis is large, and the effect of pulse discharge was not recognized. And in the comparative example 3-3, the trigger used in order to start discharge operated frequently. When a DC current sensor is inserted into the cable between the arc discharge current power source and the cathode and the time change of the current flowing through this cable is observed, current flows while the trigger is in contact with the cathode evaporation surface. As soon as it left the cathode evaporation surface, current stopped flowing and discharge could not be started. For this reason, a chromium nitride film-forming body having a predetermined thickness could not be formed.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of a droplet can be suppressed and arc discharge can be performed, without using the filter which removes a droplet.

2 Ground 4 Vacuum chamber 14 Pulse discharge current power supply 16 Trigger 20, 21 Arc type evaporation source 22 Cathode 23 Evaporation surface 24 Film forming material 29 Cathode holding flange 38 Cathode advance / retreat mechanism 42, 116 Magnetic field forming mechanism 44 Excitation power supply 46 Insulator 82 Process gas introduction system 112 Rotating shaft 120 Turntable 124 Bias power supply 130 Plasma source 200 Film forming apparatus

Claims (11)

In an arc evaporation source that heats a cathode by arc discharge to evaporate a material constituting the cathode,
An axially symmetric cylindrical magnetic field forming mechanism that houses the cathode and forms a magnetic field in a direction parallel to the central axis of the cathode in the vicinity of the evaporation surface at the tip of the cathode;
A cathode advancing and retracting mechanism for advancing and retracting the cathode in its axial direction;
A pulse discharge current power source for supplying a pulse current to the cathode;
With
The arc evaporation source, wherein the cathode has an axial length longer than a diameter.   The arc evaporation source according to claim 1, wherein the magnetic field forming mechanism has rotational symmetry.   The arc evaporation source according to claim 1 or 2, wherein the magnetic field forming mechanism includes a cylindrical permanent magnet, a permanent magnet arranged in a cylindrical shape, an electromagnet having a cylindrical iron core and a coil, or a coil.   The film-forming apparatus provided with the arc type evaporation source of any one of Claims 1-3. In the manufacturing method of the film-forming body which forms a film-forming body in the surface of a base material using the film-forming apparatus of Claim 4.
A method of manufacturing a film-forming body, wherein a frequency of the pulse discharge current power source is 50 Hz or more and 1000 Hz or less.   The manufacturing method of the film-forming body according to claim 5, wherein the frequency of the pulse discharge current power source is set to 100 Hz or more and 500 Hz or less.   The manufacturing method of the film-forming body according to claim 5 or 6 which makes the value of said pulse discharge current into 40A or more and 300A or less.   The manufacturing method of the film-forming body according to any one of claims 5 to 7, wherein a base current of the pulse discharge current is 8A or more and 20A or less or 0.3 times or less of the pulse discharge current. And the pulse discharge current pulse width T _ON of 0.3msec above, in the method of manufacturing a deposited film according to any one of claims 5-8. 10. The method for manufacturing a film formation body according to claim 5, wherein a ratio D = T _ON / T of a pulse width T _ON to a period T of the pulse discharge current is set to 0.45 or less.   The manufacturing method of the film-forming body of any one of Claims 5-10 which forms the said film-forming body by thickness of 5 micrometers or more.

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