JP2003160858A - Cathodic arc film-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cathodic arc film-forming apparatus which can reduce particles incident on a substrate, without reduction of a film-forming rate. <P>SOLUTION: A plasma beam B from a plasma generation part 1 is converted to a high-density plasma by bias voltage applied to a duct 20, while being transferred through the duct 20. Carbon ions C in the plasma beam B emitted from the duct 20 are inclined by a scanning device 3, and are incident on a substrate 41 after passing through an opening 44a of a shielding plate 44, while electrically neutral particles P go straight and are trapped by the shielding plate 44. As a result, a carbon film with a low content of the particles P is formed on the substrate 41. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathodic arc film forming apparatus used for forming a thin film using cathodic arc discharge, particularly for forming a carbon film formed on a magnetic head of a magnetic recording / reproducing apparatus. Regarding

[0002]

2. Description of the Related Art In a magnetic head and a magnetic disk of a magnetic recording / reproducing apparatus, a Cabone thin film is generally used as a protective film. In recent years, as a method for forming a protective film for a magnetic head, ta-C (tetrahedra) using a cathodic arc discharge called FCVA (Filtered Cathodic Vacuum Arc) method has been used.
l amorphous carbon) Film deposition technology is being used. In a film forming apparatus using cathodic arc discharge, arc discharge is generated with respect to a graphite target provided on the cathode to generate plasma containing carbon ions. Then, a carbon film is formed on the substrate by depositing carbon ions in the generated plasma on the substrate.

The generated plasma contains electrically neutral particles in addition to carbon ions and electrons. These particles are clusters mainly composed of carbon atoms, and are not only emitted from the target by arc discharge, but also generated by binding of ions in high-density plasma. When the carbon ions are deposited on the substrate, if the particles are mixed, the film quality is deteriorated. Therefore, the following measures are taken to reduce the particles.

The first method is a method of trapping particles by bending the path of the plasma beam while transferring the plasma beam to the substrate by using a magnetic field. In the second method, the generation of particles during the plasma transfer is suppressed by lowering the density of the plasma to form a low density plasma by elongating the transportation path of the plasma.

[0005]

However, although the particles emitted by the arc discharge can be removed by the above-mentioned first method, the particles are generated in the path from the plasma of the trap to the substrate. Therefore, the effect of reducing particles was not sufficient. Further, the second method has a problem that the film forming rate is lowered because the plasma density is low.

An object of the present invention is to provide a cathodic arc film forming apparatus capable of reducing particles entering a substrate while preventing a decrease in film forming rate.

[0007]

An embodiment of the invention will be described with reference to FIG. (1) The cathodic arc film forming apparatus according to the invention of claim 1 is arranged in the traveling path of the plasma beam B and the plasma beam generating apparatus 1 for generating the plasma beam B containing the target ions C by the cathode arc discharge. Trap 44 for capturing the plasma beam B by
The above-described object is achieved by including the deflecting device 3 which deflects and separates the target ions C included in the plasma beam B incident on the substrate 41 out of the path of the plasma beam B and makes them incident on the substrate 41. (2) The invention according to claim 2 is applied to the cathodic arc film forming apparatus according to claim 1, and is provided with a duct 20 enclosing the plasma beam B along a traveling path and to which a bias voltage is applied. is there. (3) According to the invention of claim 3, a plasma beam generator 1 for generating a plasma beam containing target ions by a cathodic arc discharge, and a chamber 4 in which a substrate 41 is loaded.
And a plasma transfer device 2 that guides the plasma beam B generated by the plasma beam generation device 1 to the substrate 41 in the chamber 4, and the substrate 41 and the plasma transfer device 2 are applied. And a shield plate 44 having a shield portion and an opening 44a, and the plasma transfer device 2 so that the plasma beam B emitted from the plasma transfer device 2 enters the shield portion of the shield plate 44.
The above-mentioned object is provided with the duct 43 that connects the chamber 4 with the chamber 4, and the deflecting device 3 that deflects the target ions C included in the plasma beam B incident on the shielding portion and causes the target ions C to enter the substrate 41 through the opening 44a. To achieve.

In the section of the means for solving the above problems, the drawings of the embodiments of the present invention are used to make the present invention easy to understand, but the present invention is limited to the embodiments of the present invention. Not something.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a cathodic arc film forming apparatus according to the present invention, showing a schematic configuration of the film forming apparatus. As shown in Figure 1,
The film forming apparatus comprises a plasma generating unit 1, a plasma transfer unit 2, a scanning device 3, a film forming chamber 4 and a control device 5 for controlling the entire device.

The plasma generator 1 comprises a cathode part 10 on which a target 11 is mounted, an anode chamber 12 in which the cathode part 10 is fixed, and a trigger 14 for triggering an arc discharge. For example, when forming a carbon film, carbon graphite is used as the target 11. Hereinafter, the carbon film formation will be described as an example.

The cathode portion 10 is an arc power source (constant current source) 13
Anode chamber 1 connected to the negative terminals of the trigger 14 and the positive terminals of the arc power supply 13
2 is grounded and has a ground potential.
The trigger 14 is rotationally driven by a driving unit 15 such as a step motor with the shaft 140 as a rotating shaft. The angle of the trigger 14 is detected by an angle sensor (not shown).

The cathode portion 10 and the anode chamber 12 are electrically insulated by the insulating member 6. A magnetic coil 16 that forms an axial magnetic field in the anode chamber 12 is provided on the outer circumference of the anode chamber 12, and an exciting current is supplied from a power supply 17. Although not shown, the cathode part 10 is provided with a cooling means such as a water cooling jacket.

The plasma transfer section 2 includes a bent duct 20.
And a magnetic coil 21 provided around it. An exciting current is also supplied from the power supply 17 to the magnetic coil 21. The plasma transfer unit 2 and the anode chamber 12 are fixed to each other via an insulating material 23, and are electrically insulated from each other. A positive bias voltage is applied to the duct 20 by a bias power supply 22.

A substrate stage 42 is provided in the film forming chamber 4, and the substrate 41, which is a film formation target, is mounted on the substrate stage 42. The substrate stage 42 rotates the substrate 41 in its plane as indicated by arrow R. Further, a shield plate 44 having an opening 44a is arranged in front of the substrate 41 (on the right side in the drawing). Film formation chamber 4
The plasma transfer unit 2 and the plasma transfer unit 2 are connected by a tilt duct 43, and the two flanges 43 a, 43 of the tilt duct 43 are connected.
b form an angle θ with each other. This tilt angle θ is
Although there is a balance with the deflectable angle of the scanning device 3 described later, it is set to about 2.5 to 10 (deg),
It is preferably 5.5 (deg).

The tilt duct 43 and the plasma transfer section 2 are fixed via an insulating member 40 and are electrically insulated from each other. A scanning device 3 is provided around the tilt duct 43 and scans the carbon ions C in the plasma beam B in the yz directions. The scanning device 3 includes, for example, a pair of C-shaped magnetic cores (not shown). The magnetic pole of one magnetic core is the tilt duct 4
3, the magnetic poles of the other magnetic core are arranged in the vertical direction with the tilt duct 43 interposed therebetween in the y direction orthogonal to the plane of the drawing. A solenoid coil (not shown) is wound around the magnetic core of the scanning device 3, and an exciting current is supplied to the solenoid coil from a power supply 31.

2A and 2B are views showing an example of the shape of the duct 20. FIG. 2A is a plan view seen from the z direction in FIG. 1, FIG. 2B is a view taken along the arrow A1 in FIG. It is an A2 arrow line view. The duct 20 is a double vent type duct having three straight pipe portions 201, 203, 205 and two bent portions 202, 204. That is, the plasma beam incident from the flange 206 provided on the straight pipe portion 201 is bent at the bent portions 202 and 204, and the straight pipe portion 20 is bent.
The light is emitted from the flange 207 provided at No. 5 at an angle θ with respect to the horizontal direction.

Next, an outline of the film forming operation will be described. When arc discharge is generated, the trigger 14 retracted to the position shown by the broken line in FIG. 1 is rotationally driven by the drive unit 15 and tilted to the target 11 side. Cathode part 10 and anode chamber 12
The potential difference between and is set to several tens to several hundreds of volts by the arc power source 13, and when the trigger tip 14a provided at the tip of the trigger 14 contacts the surface of the target 11, arc discharge is generated.

When arc discharge occurs, plasma is generated, and this plasma contains target ions (positive ions) emitted from the target 11. When the target 11 is graphite, plasma containing carbon ions is generated by arc discharge. At this time,
In addition to carbon ions, the graphite target 11 emits clusters of many carbon atoms called macroparticles.

The controller 5 constantly monitors the state of the arc power supply 13, and if it detects the occurrence of arc discharge, it drives the drive unit 1.
5 command to trigger 14 from the surface of target 11.
Pull up. At this time, trigger 1 when arc discharge occurs
The angular position of No. 4 is detected by the angle sensor described above, and the detected angular position is stored in the storage unit (not shown) provided in the control device 5. After the occurrence of arc discharge, the discharge state weakens over time, so trigger 1 again.
4 is moved to the stored position by the drive unit 15,
Control to maintain stable arc discharge.

An axial magnetic field is formed in the anode chamber 12 by the magnetic coil 16. Therefore, the plasma generated by the arc discharge, that is, the plasma containing carbon ions and electrons emitted from the target 11 is focused by this axial magnetic field and is guided to the duct 20 of the plasma transfer unit 2. Also in the plasma transfer unit 2, an axial magnetic field is formed along the axis of the duct 20 by the magnetic coil 21 provided around the duct 20, and the plasma is transferred to the film forming chamber 4 along this magnetic field. .

The plasma beam B contains carbon ions C, particles P and the like. The plasma density of the plasma beam B decreases from the center of the plasma cross section to the periphery, and the region indicated by reference symbol B in FIG. FIG. 3 qualitatively shows the distribution shape L1 of the carbon ions C and the distribution shape L2 of the particles P. The density of the particles P is much smaller than the density of the carbon ions C, but the distribution shape is shown assuming that the two have the same density for easy comparison.

Since the carbon ions C are electrically charged, they repel each other, and the distribution shape L2 is broader than the distribution shape L2 of the particles P. Therefore, a positive bias voltage is applied to the duct 20 to form a radial electric field in the duct 20, and the radial electric field is unevenly distributed in the center of the duct. At this time, the distribution shape L1 of the carbon ions C changes like the distribution shape L10, and high-density plasma is obtained.

Since the particles P are electrically neutral, the plasma beam is bent by the bent portion 20 of the duct 20.
When bent at 2, 204 (see FIG. 2), the particles P go straight and are trapped by the duct 20. Thus, by making the transfer path of the plasma beam B curved, the particles P can be removed from the beam B. However, since the particles P are also generated in the plasma beam B, the particles P are included in the plasma beam B emitted from the duct 20.

An alternating magnetic field is applied to the plasma beam B entering the tilt duct 43 from the duct 20 by the scanning device 3. As a result, carbon ion C
Is bent in its traveling direction by a magnetic field. For example, as shown in FIG.
1 is separated. FIG. 1 shows the moment when the carbon ions C are deflected in the negative direction of the z-axis, and the beam B1 passes through the opening 44a formed in the shield plate 44 and the substrate 41.
Irradiated on. On the other hand, the beam B goes straight and the shielding plate 44
It is blocked by and does not reach the substrate 41 side.

FIG. 4 is a view of the shield plate 44 seen from the plus direction of the x-axis of FIG. The circular opening 44a is formed eccentrically in the z-axis negative direction with respect to the center O of the substrate 41. On the other hand, as shown in FIG. 1, since the duct 20 is connected to the film forming chamber 4 through the tilt duct 43, the beam B containing particles is shielded above the center O (a region where the z position is positive). It collides with the plate 44 and the opening 44
It does not enter a. As shown in FIG.
Since the region between the center of the substrate 41 and the lower edge can be seen through a, the beam B1 of carbon ions C can be seen.
Is scanned in the z-axis direction, a region including the center 0 and the edge is irradiated with carbon ions C. Substrate 41 is center O
Since it is rotated about the axis, the carbon ions C are uniformly deposited on the entire surface of the substrate 41 by the scanning motion and the rotating motion.

FIG. 5 is a diagram for explaining a film forming method of a conventional cathodic arc film forming apparatus, and shows how to guide the plasma beam B to the substrate 41. Magnetic coil 2
The plasma beam B bent by 1 is emitted from the duct 20 and applied to the substrate 41 in the film forming chamber.
The plasma beam B is scanned by the scanning device 51 so that the plasma beam B is applied to the entire film formation region of the substrate 41. As described above, the particles P in the plasma beam B are removed by bending the path in the duct 20, but the particles P are also generated while entering the substrate 41 from the vicinity of the duct outlet facing the substrate surface. Is generated. The particles P are incident on the substrate 41 together with the carbon ions C, which causes deterioration in film quality.

On the other hand, in the film forming apparatus of the present embodiment, the carbon ions C deflected and separated from the plasma beam B are irradiated onto the substrate 41 immediately before the substrate 41 as described above. Therefore, the particles P formed near the exit of the duct 20 go straight like the beam B and are captured by the shielding plate 41, and do not enter the substrate 41. As a result, as described below, the number of particles P entering the substrate 41 could be reduced as compared with the conventional one.

When the ta-C film was formed by the conventional low density plasma, the film formation rate was about 0.1 (Å / sec). On the other hand, since the high-density plasma is used in the film forming apparatus of this embodiment, a large film forming rate of 0.4 (Å / sec) can be obtained. Further, regarding the particles, in the case of a film forming apparatus using a bubble vent type trap (duct 20), the particle size is 0.3 (μ
was 10 (number / cm ²⁾ or more with respect to m) above particles, but can be reduced to 1-2 (pieces / cm ²⁾ is a film forming apparatus of this embodiment.

As described above, in this embodiment, not only particles generated during arc generation but also particles generated during high-density plasma transfer can be removed with high probability. As a result, it is possible to form a high-purity carbon film in which particles are hardly mixed at a high film formation rate. The film forming apparatus of this embodiment can be applied not only to the formation of a carbon film but also to the formation of various thin films.

In the above-described embodiment, the scanning device 3 forms an AC magnetic field to deflect the carbon ions C. However, a permanent magnet is used or an electric field is formed to deflect the carbon ions C. Is also good. Further, although the duct 20 is a double vent type, a single vent type duct may be used.

Since the substrate 41 is arranged perpendicularly to the x-axis in FIG. 1, the beam B1 is incident on the substrate 41 almost vertically. On the other hand, when the substrate 41 is arranged at an angle α with respect to the beam B1 as shown in FIG. 6, since the beam B is obliquely incident on the substrate surface, migration of deposited carbon atoms is promoted and residual stress is reduced. A small carbon film is formed. For example, if the stress is 2.4 (GPa) at normal incidence, the angle α =
When incident at 45 (deg), the stress decreased to 1.4 (GPa).

In the correspondence between the embodiments described above and the elements in the claims, the plasma generator 1 constitutes a plasma beam generator, the shield plate 44 constitutes a trap, and the scanning device 3 constitutes a deflector. Further, the portion of the shielding plate 44 where the opening 44a is not formed constitutes a shielding portion.

[0033]

As described above, according to the present invention,
Target ions deflected and separated from the plasma beam are incident on the substrate, and the plasma beam containing particles is trapped by the trap and is not incident on the substrate.
Therefore, a film containing very few particles is formed on the substrate. Further, since it is not necessary to reduce the plasma density in order to reduce particles, it is possible to avoid a decrease in film forming rate.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a cathodic arc film forming apparatus according to the present invention, showing a schematic configuration of a film forming apparatus.

FIG. 2 is a diagram showing an example of the shape of a duct 20,
(A) is a plan view seen from the z direction of FIG. 1, (b) is (a)
Is a view from the arrow A1, and (c) is a view from the arrow A2.

FIG. 3 is a diagram showing a distribution shape L1 of carbon ions C and a distribution shape L2 of particles P.

4 is a view of the shielding plate 44 seen from the plus direction of the x-axis in FIG.

FIG. 5 is a diagram illustrating a film forming method of a conventional cathodic arc film forming apparatus, in which a plasma beam B onto a substrate 41 is formed.
It shows how to guide.

FIG. 6 is a diagram showing a relationship between the substrate 41 and a beam B1 when the substrate 41 is arranged so as to be inclined.

[Explanation of symbols]

1 Plasma generator 2 Plasma transfer unit 3,51 scanning device 4,50 Deposition chamber 5 control device 11 targets 12,16 Magnetic coil 20 ducts 22 Bias power supply 41 substrate 42 Substrate stage 43 Tilt duct 44 Shield 44a opening C carbon ion P particles

Claims (3)

[Claims] 1. A plasma beam generator for generating a plasma beam containing target ions by cathodic arc discharge, a trap arranged in the traveling path of the plasma beam for trapping the plasma beam, and a trap for entering the trap. A cathodic arc film forming method, comprising: a deflecting device that deflects and separates the target ions contained in a plasma beam out of a path of the plasma beam and makes them incident on a substrate, and forms a thin film on the substrate. apparatus. 2. The cathodic arc film forming apparatus according to claim 1, further comprising a duct surrounding the plasma beam along the traveling path and having a bias voltage applied thereto. Membrane device. 3. A plasma beam generator for generating a plasma beam containing target ions by cathodic arc discharge, a chamber in which a substrate is loaded, and a plasma beam generated by the plasma beam generator to a substrate in the chamber. In a cathodic arc film forming apparatus equipped with a plasma transfer device that guides with, a shield plate disposed between the substrate and the plasma transfer device, the shield plate having a shield part and an opening, and emitting from the plasma transfer device. A duct connecting the plasma transfer device and the chamber so that the generated plasma beam is incident on the shield part of the shield plate; and deflecting the target ions contained in the plasma beam incident on the shield part, And a deflection device for making the light incident on the substrate through an opening. Click the film-forming apparatus.