JP2004162084A - Film deposition method, and film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition method and a film deposition system for obtaining a film having excellent flatness and homogeneity. <P>SOLUTION: When a target material is evaporated from a target by arc discharge and deposited on a substrate, the target is cooled during the arc discharge, and the target is rotated so that the component of the tangential direction of the rotational speed of the discharge part of the target is controlled to ≥5 mm/sec. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a film formation method of evaporating a target material from a target by arc discharge and depositing the target material on a substrate (Filtered Cathodic Arc method or Filtered Cathodic Vacuum Arc method, hereinafter sometimes abbreviated as FCA method in this specification). And an apparatus (hereinafter, may be abbreviated as an FCA apparatus in the present specification) (for example, see Non-Patent Document 1).
[0002]
[Prior art]
In order to meet the demand for a higher recording density of a magnetic recording device (a so-called hard disk drive) with a head floating as an information recording device, the distance between a magnetic layer of a magnetic recording medium such as a hard disk and a magnetic head recording unit must be increased. Some magnetic spacing must be reduced.
[0003]
Therefore, the protective film of the disk having the configuration as shown in FIG. 1 is required to be thinner and harder. In FIG. 1, the recording medium has a structure in which a Ni-P layer 2, an underlayer 3, a magnetic layer 4, a protective film layer 5, and a lubricant layer 6 are laminated on a substrate 1 such as Al or glass. I have. The underlayer 3 is often made of, for example, a Cr-based material, and the magnetic layer 4 is often made of a Co-based material. As can be seen from this figure, it is effective to reduce the magnetic pacing by making the protective film layer 5 thinner, but the thinner the protective film, the higher the hardness of the protective film is required. .
[0004]
Conventionally, a diamond-like carbon (hereinafter abbreviated as DLC) film by sputtering or CVD has been used for these protective films, but the hardness is not sufficient for a demand for further thinning in the future. , Is considered incapable.
[0005]
An FCA method is available as a method for responding to the need for such an extremely hard DLC film. In this method, generally, carbon is used as a cathode, plasma-like particles are generated by arc discharge using the carbon as a target, and the function of a magnetic deflector of a mass spectrometer is used to generate positive plasma-like carbon. In this method, only particles are selected and irradiated onto the substrate.
[0006]
In this method, arc discharge having a discharge point temperature of 10,000 ° C. or more is used, so that even heat-resistant carbon can be easily melted and sublimated. In addition, since the film is formed only of carbon, the film does not contain hydrogen, and therefore has no C—H bond that causes a decrease in hardness, and a DLC film with high hardness rich in C—C sp ³ bonds can be obtained. Can be
[0007]
However, it has been pointed out that an apparatus that performs this method deposits carbon particles having a large particle diameter on a substrate, and loses the flatness and uniformity of the film.
[0008]
[Non-patent document 1]
"Journal of Applied Physics", 2001, Vol. 40, p. 777-782
[0009]
[Problems to be solved by the invention]
An object of the present invention is to solve the problem that the flatness and uniformity of a film are lost in the above-mentioned FCA method. Still other objects and advantages of the present invention will become apparent from the following description.
[0010]
[Means for Solving the Problems]
According to one embodiment of the present invention, there is provided a film forming method in which a target material is evaporated from a target by arc discharge and deposited on a substrate, wherein the target is rotated during the arc discharge. This can solve the problem that the flatness and uniformity of the film are lost in the FCA method.
[0011]
Preferably, the target material is carbon, the tangential component of the rotation speed of the discharge part of the target is 5 mm / sec or more, and the target is cooled. Further, it is preferable to form a magnetic disk protective film by deposition. This is because the FCA method makes it easy to obtain a protective film for a magnetic disk having excellent flatness and uniformity.
[0012]
According to another aspect of the present invention, in a film forming apparatus for evaporating a target material from a target by arc discharge and depositing the target material on a substrate, the target material is carbon, and Is provided, and the target is rotated so that the tangential component of the rotation speed of the discharge part of the target is 5 mm / sec or more.
[0013]
In addition, further features of the present invention will be clarified in the embodiments and drawings of the invention described below.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, examples, and the like. It should be noted that these drawings, examples, etc., and the description are merely examples of the present invention, and do not limit the scope of the present invention. It goes without saying that other embodiments can also belong to the category of the present invention as long as they conform to the gist of the present invention.
[0015]
FIG. 2 is a cross-sectional model diagram of an example of a conventional FCA apparatus. In FIG. 2, a substrate 22 on which a film is to be formed is installed in a chamber 21 kept in a vacuum. A target 23 made of carbon is set on a support 24. Using the target 23 as a cathode and the ring-shaped anode 26 as an anode to start an arc discharge by striking the striker 25 to generate a sustained arc discharge between the target 23 and the ring-shaped anode 26, a target material is obtained. The carbon becomes positive plasma-like carbon particles 28, which are guided into the chamber 21 by the action of a filter field (magnetic deflection filter) 29, and the substrate 22 is irradiated with the plasma-like carbon particles 28, A DLC film is formed. A scanning magnetic field (also referred to as an XY deflection electrode) 30 at the exit of the filter field 29 has a function of making the film thickness of the plasma-like carbon particles 28 formed on the substrate 22 uniform. The state of the target 23 can be seen from the sight glass 27.
[0016]
The filter field 29 has a function of bending the trajectory of the plasma-like particles, and particles having a large mass (M) / charge amount (e) have a large straightness, and therefore collide with the wall surface of the filter field 29 and are captured. By this action, of the plasma-like carbon particles 28, those having a large particle size, such as dust, collide with the wall surface of the filter field 29 and become deposited on the wall surface, but the function of the filter field 29 can be said to be sufficient. However, as described above, there is a case where the film is irradiated onto the base material 22 as it is, which causes a loss of flatness and uniformity of the film.
[0017]
In contrast, an FCA device according to the present invention is shown in FIG. In FIG. 3, the overall operation is the same as in FIG. 2, except that the target 23 is rotated by the stepping motor 31 and cooled by the cooling water system 32.
[0018]
The above-mentioned problems of the prior art can be solved by rotating a carbon target. The reason is that by rotating the target itself, it is possible to forcibly move the discharge point on the target as the cathode, and it is possible to prevent uneven dissolution of the target due to localization of the discharge point. It is thought that it is. As a result of preventing non-uniform dissolution of the target, the generation of large-diameter plasma-like carbon particles is suppressed, and only the small-diameter plasma-like carbon particles reach the substrate 2 and have high flatness. , A homogeneous film can be obtained. Specifically, the plasma-like carbon particles having a small particle diameter are ideally one carbon ion. However, it is not inconceivable that a plurality of the carbon-like particles are gathered.
[0019]
As the target rotation speed at this time, it is desirable that the tangential component of the rotation speed of the target at the discharge point be 5 mm / sec or more. If it is less than 5 mm / sec, large plasma-like carbon particles are likely to be generated. Note that the direction of rotation may be either clockwise or counterclockwise, and swinging motion may be possible. Further, the target may be movable up and down. In the case of being able to move up and down, the discharge point draws a spiral trajectory in combination with the rotational movement.
[0020]
Note that the tangential component of the rotation speed of the discharge portion of the target is, for example, a target point at a discharge point 82 where a discharge 81 occurs on the target 23 rotating in the x direction as shown in the perspective view of FIG. 23 means the tangential component of the rotation speed. That is, it means the tangential component Y of the rotational speed of the target 23 along the trajectory 83 drawn as a circle when the target is viewed from above as shown in FIG.
[0021]
Further, cooling the target to suppress a rise in the temperature of the target at the time of discharge can reduce the melting area of the target at the discharge point, which is useful for obtaining a uniform film with high flatness. In particular, in combination with the above rotation, a uniform film having high flatness can be obtained more efficiently.
[0022]
As a cooling method in this case, any known method can be used as long as it does not violate the gist of the present invention. FIG. 4 is an example of this, and shows a state in which a cylinder partitioned into two is accommodated inside the target 23 and cooling water is conducted.
[0023]
As shown in FIG. 5, an apparatus having a plurality of irradiation units of plasma-like carbon particles may be used. In the above description, the case where the target material is carbon has been described. However, the present invention is not limited to this, and any substance capable of arc discharge may be used. It is considered that the present invention is applicable to the case where other conductive materials, for example, metals are used. Examples include W, Ti, and the like.
[0024]
The film forming method and the film forming apparatus according to the present invention can be used for any purpose, but are particularly useful for producing a magnetic disk protective film, and are required to be thinner and have higher hardness. Flatness and homogeneity of the magnetic disk protective film can be improved.
[0025]
【Example】
Next, examples and comparative examples of the present invention will be described in detail.
[0026]
[Example 1]
Using the FCA apparatus shown in FIGS. 3 and 4, the DLC film was discharged on a Si wafer by discharging under the conditions of a film forming chamber pressure of 5 × 10 ⁻³ Pa, a discharge voltage of 120 V, and a discharge current of 60 A. The film was formed over a period of seconds. The tangential component of the target rotation speed was rotated at a speed of 4 mm / sec, and 20 ° C. cooling water was used as the cooling water in FIG.
[0027]
With respect to the formed DLC film having a thickness of 0.1 μm, the thickness and hardness of the formed DLC film were evaluated by an ellipsometer. As a result, the hardness was 50 GPa and the density was 3.1 g / cm ³ .
[0028]
In addition, the abundance of surface defects on the film surface was evaluated using a surface defect evaluation device utilizing light scattering. FIG. 6 shows an observation result (photograph) of the surface defect observation device. In the photograph of FIG. 6, the portions that appear black are surface defects. The term “surface defect” as used herein means a projection on the film surface which is considered to be formed by large-diameter carbon particles or the like, and is often in a lump.
[0029]
It was noted from photographic observation that when the cooling with water was stopped, the number of surface defects increased.
[0030]
[Example 2 and Comparative Example 1]
Example 1 was the same as Example 1 except that the tangential component of the target rotation speed was variously changed.
[0031]
As a result, the relationship with the area ratio of the surface defects is as shown in FIG. 7. Compared with the case where the target is not rotated, by rotating the target according to the present invention, the area ratio of the surface defects is rapidly reduced, and It can be seen that the surface defect is almost 0 when the tangential direction component is 5 mm / sec or more. In addition, the area ratio of the surface defect means, for example, a percentage of “the area of the part that looks black” and “the area of the area that looks white and the area of the part that looks black” in FIG.
[0032]
It should be noted that the film produced when the tangential component of rotation was 5 mm / sec or more had no defect, indicating that it was suitable as a magnetic disk protective film.
[0033]
From the contents disclosed above, the inventions shown in the following supplementary notes can be derived.
[0034]
(Supplementary Note 1) A film forming method in which a target material is evaporated from a target by arc discharge and deposited on a substrate, wherein the target is rotated during arc discharge.
[0035]
(Supplementary note 2) The film forming method according to supplementary note 1, wherein the target material is a conductive substance.
[0036]
(Supplementary note 3) The film forming method according to supplementary note 1, wherein the target material is carbon or metal.
[0037]
(Supplementary Note 4) The film forming method according to Supplementary Note 1, wherein the target material is carbon, and a tangential component of a rotation speed of a discharge part of the target is 5 mm / sec or more.
[0038]
(Supplementary note 5) The film forming method according to any one of Supplementary notes 1 to 4, wherein the target is cooled during arc discharge.
[0039]
(Supplementary note 6) The film forming method according to any one of Supplementary notes 1 to 5, wherein a magnetic disk protective film is formed by the deposition.
[0040]
(Supplementary Note 7) A film forming apparatus for evaporating a target material from a target by arc discharge and depositing the target material on a substrate, wherein the target is rotated during the arc discharge.
[0041]
(Supplementary note 8) The film forming apparatus according to supplementary note 7, wherein the target material is a conductive substance.
[0042]
(Supplementary note 9) The film forming apparatus according to supplementary note 7, wherein the target material is carbon or metal.
[0043]
(Supplementary note 10) The film forming apparatus according to supplementary note 7, wherein the conductive substance is carbon, and a tangential component of a rotation speed of the discharge unit of the target is 5 mm / sec or more.
[0044]
(Supplementary Note 11) The film forming apparatus according to any one of Supplementary Notes 7 to 10, wherein the target is cooled.
[0045]
(Supplementary Note 12) The film forming apparatus according to any one of Supplementary Notes 7 to 11, wherein the magnetic disk protective film is formed by the deposition.
[0046]
(Supplementary Note 13) In a film forming apparatus that evaporates a target material from a target by arc discharge and deposits the target material on a substrate,
The target material is carbon,
During the arc discharge, the target is cooled, and the target is rotated such that the tangential component of the rotation speed of the discharge part of the target is 5 mm / sec or more.
Film forming equipment.
[0047]
【The invention's effect】
By the FCA method described above, a film having excellent flatness and uniformity, for example, a DLC film having excellent flatness and uniformity can be obtained. This DLC film is useful as a magnetic disk protective film.
[Brief description of the drawings]
FIG. 1 is a model diagram showing a cross-sectional structure of a magnetic recording medium.
FIG. 2 is a cross-sectional model diagram of an example of a conventional FCA apparatus.
FIG. 3 is a cross-sectional model diagram of an example of the FCA device according to the present invention.
FIG. 4 is a cross-sectional model diagram showing a state of a cooling system inside a target.
FIG. 5 is a cross-sectional model diagram of an example of an FCA apparatus having two irradiation units of plasma-like carbon particles.
FIG. 6 is a photograph showing an observation result of a surface defect.
FIG. 7 is a diagram showing a relationship between a rotation speed (tangential component) of a discharge part of a target and an area ratio of a surface defect.
FIG. 8 is a perspective model diagram illustrating a tangential component of a rotation speed of a discharge unit of a target.
FIG. 9 is a model diagram of the target as viewed from above, for explaining the tangential component of the rotation speed of the discharge portion of the target.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Ni-P plating layer 3 Underlayer 4 Magnetic layer 5 Protective film layer 6 Lubricant layer 21 Chamber 22 Base material 23 Target 24 Support stand 25 Striker 26 Ring-shaped anode 27 Sight glass 28 Positive plasma-like carbon particles 29 Filter Field 30 Scanning magnetic field 31 Stepping motor 32 Cooling water system 81 Discharge 82 Discharge point 83 Trace of discharge point

Claims (5)

A film forming method in which a target material is evaporated from a target by arc discharge and deposited on a substrate, wherein the target is rotated during arc discharge. The film forming method according to claim 1, wherein the target material is carbon, and a tangential component of a rotation speed of a discharge part of the target is 5 mm / sec or more. The method according to claim 1, wherein the target is cooled during arc discharge. The film forming method according to claim 1, wherein a magnetic disk protective film is formed by the deposition. In a film forming apparatus that evaporates a target material from a target by arc discharge and deposits the target material on a substrate,
The target material is carbon,
During the arc discharge, the target is cooled, and the target is rotated such that the tangential component of the rotation speed of the discharge part of the target is 5 mm / sec or more.
Film forming equipment.

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