JP2001334192A - Lubricant coat processing device, lubricant coat processing method and lubricant applying method on magnetic disk medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of particles and the waviness of liquid surface without reducing the flow rate of circulating filtration in a lubricant coat processing device, a lubricant coat processing method and a lubricant applying method on a magnetic disk medium. SOLUTION: A processing liquid 2 for applying a lubricant on the surface of a substrate 3 is supplied from a part below the liquid level, where is free from affecting the liquid surface, and circulated and filtered by a down flow system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant applying apparatus, a lubricant applying method, and a method of applying a lubricant to a magnetic disk medium, and more particularly to a hard disk constituting a hard disk drive (HDD) device. When applying a lubricant layer on a protective film such as DLC (diamond-like carbon) provided on the surface of a magnetic disk medium such as a magnetic disk, the structure of a lubricant application tank for preventing particles from re-adhering and applying the lubricant A lubricant application processing apparatus characterized by a solution circulation method, a lubricant application processing method, and
The present invention relates to a method for applying a lubricant to a magnetic disk medium.

[0002]

2. Description of the Related Art Currently, a hard disk drive used for an external storage device or the like is a CSS (Contact Start).
As typified by the Stop method, the magnetic disk medium and the magnetic head are in contact at the time of startup, and after the startup, there is intermittent contact between the magnetic head and the magnetic disk medium due to external vibration or the like.

[0003] When a magnetic layer constituting a magnetic disk medium used in such a magnetic recording device does not have lubricity or has a very low lubricity, a long-time contact occurs.
There is a problem that the magnetic film of the magnetic head or the magnetic disk medium is worn, so-called head clogging or head crash occurs.

Therefore, in general, in order to protect a magnetic layer constituting a magnetic recording medium such as a magnetic disk medium, a protective lubricating layer having a thickness of 5 to 50 nm is formed on the magnetic layer by a PVD method or a CVD method. DL in amorphous state
C film or the like is formed as a protective layer.
An extremely thin lubricant layer of about 90 ° is formed.

The protective layer protects information recorded on the recording layer composed of the magnetic layer and has the effect of enhancing the slidability of the magnetic head. Due to the poor durability, as described above, a method of applying a lubricant having a thickness of about 10 to 90 ° on the surface of the protective layer to improve the durability of the protective layer has been widely adopted.

As such lubricants, perfluoropolyether lubricants and aliphatic hydrocarbon lubricants are known, and the main role of such lubricants is that they are adsorbed on the surface of the protective layer. To prevent the magnetic head slider from directly contacting the protective layer, and to significantly reduce the frictional force of the magnetic head slider sliding on the magnetic recording medium.

Here, a conventional lubricant coating apparatus will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a conceptual perspective view of a conventional lubricant coating apparatus. When a lubricant coating solution 22 is thinly applied to a magnetic disk substrate 23 to form a lubricant layer, a plurality of magnetic disks are formed. The substrate 23 is held by the disk holding arm 24, and the disk holding arm 24 is lowered to move the magnetic disk substrate 23 into the lubricant application solution 22 stored in the lubricant application processing tank 21.
It is performed by immersing it and then slowly pulling it up.

In this case, the disk holding arm 24 is moved to, for example, 1.0 mm / mm by using a pulling mechanism (not shown).
The solvent remaining on the surface of the magnetic disk substrate 23 was evaporated by slowly pulling it up at a constant pulling speed of seconds to form a lubricant layer having a thickness of about 10 to 90 °.

In such a lubricant application step, a plurality of magnetic disk substrates 23 are generally processed at one time, and such processing is generally performed a plurality of times using the same lubricant application solution 22.

On the other hand, a pre-process before the lubricant application process is a film forming process such as a sputtering process of a magnetic film or a protective film, a polishing process for removing abnormal projections and the like on the substrate surface accompanying the film forming process, or a polishing process. A polishing process using a tape with particles attached thereto. In this process, the magnetic disk substrate 2
Foreign matter tends to adhere to the surface of the magnetic recording medium 3, but with the recent increase in the recording density of magnetic recording media, the adhesion of submicron-order particles has become a problem.

The particles adhering to the surface of the magnetic disk substrate 23 are brought into the lubricant applying step as they are and are added to the lubricant applying solution 22 by the magnetic disk substrate 23.
Is immersed, the particles are dispersed in the lubricant application solution 22, and a part of the particles goes to the liquid surface, and when the magnetic disk substrate 23 is pulled up from the liquid surface, there is a possibility that the particles will be re-attached, If attached, there is a problem that the production yield is reduced.

The particles brought into the lubricant application solution 22 accumulate in the tank each time the number of times of the application processing increases, and the number of particles re-adhering to the magnetic disk substrate 23 gradually increases. Becomes At present, the problem of reattachment of particles in the lubricant coating tank 21 is dealt with by circulating and filtering the lubricant coating solution 22 in the lubricant coating tank 21. Now, a conventional circulation filtration method will be described with reference to FIG.

FIG. 6 is a conceptual configuration diagram of a conventional lubricant application processing apparatus. The lubricant application processing tank 21 includes a main coating processing tank 25 and a circulation tank 26. Main coating tank 25
The lubricant application solution 22 overflowing from the tank flows into the circulation tank 26, is discharged from the tank outlet 27 provided at the bottom of the circulation tank 26, is filtered by the filter 28, and is filtered by the circulation pump 29 into the main coating tank 25. By supplying to the main coating tank 25 from the supply port 30 provided at the bottom,
The lubricant application solution 22 is circulated.

In this case, the particles 31 carried by the magnetic disk substrate 23 move near the liquid surface by the flow of the lubricant application solution 22 supplied to the supply port 30 provided at the bottom, and are moved from the main application tank 25. It flows into the circulation tank 26 together with the overflowing lubricant application solution 22, and is filtered by the filter 28.

In this case, if an appropriate circulation filtration flow rate is set with respect to the tank capacity of the main coating tank 25, the number of particles in the tank becomes almost constant and stable even if continuous processing is performed. For example, in such a circulation filtration type lubricant coating apparatus, the increase or decrease in the number of particles of 1 μm or more was within ± 10.

[0016]

However, in order to make the thickness of the lubricant layer constant, it is necessary to pull up the magnetic disk substrate 23 from the liquid surface at a constant speed. In the processing apparatus, there is a problem in that the liquid surface undulates because the lubricant application solution needs to overflow, and the undulation of the liquid surface affects the thickness of the lubricant layer. In particular, when the thickness of the lubricant layer is reduced to about 10 mm with the increase in the recording density of the magnetic recording medium, the allowable thickness distribution becomes about ± 2 mm, and the liquid surface has a problem of waviness. Becomes

In order to solve such a problem of the liquid surface waving, the circulation filtration flow rate may be reduced. For example, when the tank capacity is 10 liters, the circulation filtration flow rate is set to 1 liter / min or less. In this case, the liquid surface state hardly affects the thickness of the lubricant layer.

However, such a circulating filtration flow rate is lower than an appropriate value when applied during mass production, and it is not sufficient to suppress the increase of particles at such a circulating filtration flow rate. There is a problem that the number of particles increases in proportion to the number of continuous processes.

The magnetic disk substrate 23 before the coating step
In order to remove the particles attached to the surface of the magnetic disk substrate 23, the surface of the magnetic disk substrate 23 may be cleaned before the coating step. However, there is a problem that the number of manufacturing steps is increased. However, there is a problem that a so-called watermark is formed on the surface of the magnetic disk substrate 23 and affects the manufacturing yield.

Accordingly, it is an object of the present invention to prevent the number of particles from increasing and to prevent the liquid surface from waving without reducing the circulation filtration flow rate.

[0021]

FIG. 1 is an explanatory view of the principle configuration of the present invention. Referring to FIG. 1, means for solving the problems in the present invention will be described. See FIG. 1 In order to solve the above-mentioned problems, in the present invention, when a lubricant is applied to the surface of the substrate 3, especially the surface of the magnetic disk medium, the processing liquid 2 for applying the lubricant affects the liquid level. And is supplied from the lower part of the liquid surface where the water is not supplied, and is circulated and filtered by a down flow method.

As described above, the processing liquid 2 is circulated and filtered by the down-flow method using the circulating pump 9, whereby
The particles 5 released from the substrate 3 are likely to be entrained in the flow of the processing liquid 2 toward the discharge port 6 in the bottom provided at the bottom and reach the upper liquid level. Is reduced on the substrate 3. In addition, since the supply port 7 of the processing liquid 2 is provided below the liquid surface that does not affect the liquid surface, for example, about 10 to 20 mm below the liquid surface, the liquid surface does not undulate, and therefore, the lubricant The thickness of the layer can be made uniform.

Further, the present invention is characterized in that an ultrasonic wave transmitting mechanism is provided in the lubricant coating tank 1, and in particular, a swinging mechanism of the substrate 3 is provided.

As described above, the provision of the ultrasonic wave transmitting mechanism in the lubricant coating tank 1 promotes the separation of the particles 5 from the substrate 3, so that the effect of removing the particles by the filter 8 can be further enhanced. it can.

When the ultrasonic wave becomes a standing wave,
Since the particles 5 are hard to be partially released, the effect of releasing the particles 5 by the ultrasonic waves is remarkably exhibited by vertically moving the substrate holder 4 and swinging the substrate 3.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a conceptual configuration diagram of a lubricant application processing apparatus according to the first embodiment of the present invention. The lubricant application processing apparatus accommodates a lubricant application solution 12 and a discharge port in a tank. A lubricant application tank 11 having a supply port 15 and a supply port 18, a filter 16 for filtering the lubricant application solution 12 discharged from the discharge port 15 in the tank, and a supply and circulation of the lubricant application solution 12 from the supply port 18. Circulation pump 17, magnetic disk substrate 13
While moving up and down to move the magnetic disk substrate 13
A disk holding arm 14 is provided for dipping in the lubricant application solution 12 and pulling it up. The lubricant application solution 12 may be accommodated in the lubricant application tank 11 so that the position of the supply port 18 is 10 to 20 mm below the liquid level. In this case, the circulating filtration flow rate is, for example, 1 l / min.

In this case, the magnetic disk substrate 13 is formed, for example, by 2.5 inches (≒
A CoCrPt magnetic recording layer having a thickness of, for example, 20 nm is provided on a 6.35 cm) glass substrate with a NiP underlayer interposed therebetween, and then a CoCrPt layer is formed by plasma CVD.
t A DLC protective layer having a thickness of, for example, 6 nm is deposited on the magnetic recording layer.

The lubricant coating solution 12 is, for example, a perfluoropolyether having a piperonyl group at a terminal, which is a fluorine-based lubricant, specifically, Fomblin.
(Trade name) AM3001 (trade name, manufactured by Ausimont)
Was dissolved in a solvent, Fluorinert (trade name) FC77 (trade name, manufactured by Sumitomo 3M).

In such a lubricant coating apparatus, the disk holding arm 14 is lowered to accommodate the magnetic disk substrate 13 in the lubricant coating tank 11 while circulating and filtering the lubricant coating solution 12 in a downflow manner. For example, by dipping in the lubricant application solution 12 for 30 seconds, and then pulling up at a pulling speed of, for example, 1.0 mm / sec, the film thickness of the surface of the magnetic disk substrate 13 becomes
For example, it is coated with a lubricant layer of 5 to 50 degrees, for example, 10 degrees.

In this case, the particles 19 brought into the lubricant application solution 12 by the magnetic disk substrate 13
Is trapped in the downward flow of the lubricant application solution 12, moves to the discharge port 15 in the tank, and is filtered by the filter 16. Incidentally, when the circulating filtration process was performed by this lubricant coating apparatus, the number of particles having a size of 1 μm or more increased or decreased by -20 to -40.

Therefore, the probability of the particles 19 diffusing and moving to the liquid surface decreases, so that the number of the particles 19 near the liquid surface decreases, and when the magnetic disk substrate 13 is lifted, the particles 19 adhere to the surface of the magnetic disk substrate 13. Can be prevented from re-adhering.

Further, since the supply port 18 of the lubricant application solution 12 is located 10 to 20 mm below the liquid level, the supply port 1
The surface of the lubricant is not waved by the lubricant application solution 12 flowing from the nozzle 8, so that the thickness of the lubricant layer applied to the magnetic disk substrate 13 can be made uniform.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a conceptual configuration diagram of a lubricant application processing apparatus according to a second embodiment of the present invention. The lubricant application processing tank of the lubricant application processing apparatus according to the first embodiment described above. 11 is provided with an ultrasonic oscillator 20, and the other configuration is exactly the same as that of the lubricant application processing apparatus of the first embodiment, so that the description of the configuration is omitted.

In the second embodiment, the ultrasonic wave is emitted from the ultrasonic oscillator 20 toward the magnetic disk substrate 13 while the magnetic disk substrate 13 is immersed in the lubricant application solution 12, so that the magnetic disk Particles 19 attached to the surface of the substrate 13 are easily released,
The separated particles 19 are discharged out of the tank by the downward water flow and are filtered by the filter 16, so that the effect of removing the particles 19 is enhanced.

In this case, it is desirable that the output and frequency of the ultrasonic wave be changed depending on the size of the particle 19, for example, the frequency may be changed in a direction to increase as the size of the particle 19 decreases.
If the liquid surface is slightly waved by the ultrasonic waves, the ultrasonic oscillator 20 may be stopped when the magnetic disk substrate 13 is pulled up.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a conceptual configuration diagram of a lubricant application processing apparatus according to a third embodiment of the present invention. The disk holding arm 14 of the lubricant application processing apparatus according to the second embodiment described above. The vertical movement mechanism is used to swing the magnetic disk substrate 13 up and down, and the other configuration is exactly the same as that of the lubricant application processing apparatus of the second embodiment. Is omitted.

In the third embodiment, while the magnetic disk substrate 13 is immersed in the lubricant application solution 12 and the ultrasonic oscillator 20 irradiates the ultrasonic waves toward the magnetic disk substrate 13, the disk holding arm 14 to move the magnetic disk substrate 13 up and down by 1 to 2c.
It swings at a speed of m / sec.

That is, when the ultrasonic wave is applied to the magnetic disk substrate 13, a standing wave may be generated. When the standing wave is generated, the particles 19 are hardly released on a part of the surface of the magnetic disk substrate 13. Therefore, the standing wave is prevented from being generated by swinging the magnetic disk substrate 13 up and down, whereby the particles 19 attached to the surface of the magnetic disk substrate 13 are more easily released.

The embodiments of the present invention have been described above. However, the present invention is not limited to the configurations and conditions described in each embodiment, and various modifications are possible. For example, in each of the above-described embodiments, the in-tank discharge port 15 is provided at the bottom of the lubricant coating tank 11, but is not necessarily limited to the bottom.
1 may be provided on the lower side surface.

Further, in each of the above embodiments, the lubricant application solution 12 discharged from the discharge port 15 in the tank is directly circulated and subjected to the filtering process by the filter 16, but the temperature control mechanism is once provided. After being discharged to the lubricant application solution tank, the temperature is controlled in the lubricant application solution tank, and then circulated to be filtered by the filter 16.

In each of the above embodiments, the lubricant is applied to the magnetic disk substrate. However, the present invention is not limited to the magnetic disk substrate, and a thin lubricant may be applied to the surface of a thin plate-shaped substrate. It is applied when it does.

Here, with reference to FIG. 1 again, additional notes of the present invention will be described. See FIG. 1 (Supplementary Note 1) In a lubricant application processing apparatus for applying a lubricant to the surface of the substrate 3, a discharge port 6 in the tank for circulating and filtering the processing liquid 2 is provided at a lower portion of the lubricant application processing tank 1. Wherein the supply port 7 is provided below the liquid surface which does not affect the liquid surface state. (Supplementary Note 2) The supply port 7 is set at 10 to 20 mm from the liquid level.
The lubricant coating apparatus according to claim 1, wherein the apparatus is provided below. (Supplementary Note 3) The lubricant application processing apparatus according to Supplementary Note 1 or 2, wherein an ultrasonic transmission mechanism is provided in the lubricant application treatment tank 1. (Supplementary Note 4) The lubricant application processing device according to Supplementary Note 3, wherein a swing mechanism for swinging the substrate 3 is provided. (Supplementary Note 5) In the lubricant application processing method of applying a lubricant to the surface of the substrate 3, the processing liquid 2 is supplied from a supply port 7 provided at a lower portion of the liquid surface which does not affect the liquid surface state.
After the substrate 3 is immersed in the processing liquid 2 contained in the lubricant coating tank 1 while being circulated and filtered through the tank discharge port 6 provided in the lower part of the lubricant coating tank 1, the substrate 3 is removed. A method for applying a lubricant, wherein the method is applied. (Supplementary Note 6) The lubricant applying process according to Supplementary Note 5, wherein the substrate 3 is immersed in the treatment liquid 2 in a state where the treatment liquid 2 is subjected to ultrasonic vibration in the lubricant application treatment tank 1. Method. (Supplementary Note 7) The lubricant application according to Supplementary Note 6, wherein the substrate 3 is oscillated in the treatment liquid 2 in a state where the treatment liquid 2 is subjected to ultrasonic vibration in the lubricant application treatment tank 1. Processing method. (Supplementary Note 8) In a lubricant applying method for applying a lubricant to the surface of a magnetic disk medium, the processing liquid 2 is supplied from a supply port 7 provided at a lower portion of the liquid surface which does not affect the liquid surface state, and the lubricant is applied. Outlet 6 in the tank provided at the lower part of the processing tank 1
The magnetic disk medium is immersed in the processing liquid 2 contained in the lubricant application processing tank 1 while being circulated and filtered, and then the magnetic disk medium is pulled up. Method.

[0043]

According to the present invention, since the circulation filtration type lubricant coating apparatus is constituted by the down flow system, the liquid surface does not undulate even if the circulation filtration flow rate is increased. Since the particles do not adhere again when the magnetic disk substrate is pulled up and the thickness of the lubricant layer can be made uniform, the production yield of the magnetic disk medium can be improved, and the hard disk drive and the like can be improved. Greatly contributes to the improvement of the reliability of

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of the present invention.

FIG. 2 is a conceptual configuration diagram of a lubricant application processing apparatus according to the first embodiment of the present invention.

FIG. 3 is a conceptual configuration diagram of a lubricant application processing apparatus according to a second embodiment of the present invention.

FIG. 4 is a conceptual configuration diagram of a lubricant application processing device according to a third embodiment of the present invention.

FIG. 5 is a conceptual perspective view of a conventional lubricant application processing apparatus.

FIG. 6 is a conceptual configuration diagram of a conventional lubricant application processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lubricant application processing tank 2 Processing liquid 3 Substrate 4 Substrate holder 5 Particle 6 Outlet in tank 7 Supply port 8 Filter 9 Circulation pump 11 Lubricant application processing tank 12 Lubricant application solution 13 Magnetic disk substrate 14 Disk holding arm Reference Signs List 15 Outlet in tank 16 Filter 17 Circulation pump 18 Supply port 19 Particle 20 Ultrasonic oscillator 21 Lubricant coating tank 22 Lubricant coating solution 23 Magnetic disk substrate 24 Disk holding arm 25 Main coating tank 26 Circulating tank 27 Tank Internal discharge port 28 Filter 29 Circulation pump 30 Supply port 31 Particles

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 5/84 G11B 5/84 BF Term (Reference) 4D075 AB02 AB12 AB36 AB41 CA47 DA06 DB14 DC22 DC28 EA37 4F040 AA12 AC02 BA47 CC02 CC08 CC10 CC16 4F042 AA08 CB20 CB25 CC07 CC22 5D112 AA07 AA24 BC01 CC01

Claims (3)

[Claims] In a lubricant coating apparatus for applying a lubricant to a surface of a substrate, an outlet in a tank for circulating and filtering a processing liquid is provided at a lower portion of the lubricant coating tank, and a supply port is provided at a liquid level. A lubricant application treatment device provided below a liquid surface which does not affect the state. 2. A method for applying a lubricant to a surface of a substrate, comprising: supplying a processing liquid from a supply port provided at a lower portion of the liquid surface which does not affect a liquid surface state; A lubricant application processing method, comprising: immersing a substrate in a processing liquid contained in the lubricant application processing tank while discharging and circulating filtration through a discharge port in a tank provided at a lower part of the tank; and then lifting the substrate. . 3. A lubricant applying method for applying a lubricant to a surface of a magnetic disk medium, wherein a processing liquid is supplied from a supply port provided at a lower portion of the liquid surface which does not affect a liquid surface state, and a lubricant applying process is performed. The magnetic disk medium is immersed in the processing liquid contained in the lubricant application processing tank while being circulated and filtered through a discharge port in the tank provided at the lower part of the tank, and then the magnetic disk medium is pulled up. A method of applying a lubricant to a magnetic disk medium.