JP3207829B2 - Method of bonding lubricant to magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method of bonding a lubricant to a magnetic disk, and more particularly, to a method of flying static friction during operation of a hard disk drive.
The present invention relates to a method of bonding a lubricant to a magnetic disk of the hard disk drive in order to reduce tiction).

[0002]

2. Description of the Related Art Hard disk drives are generally
Air bearing slider to read / write data on the surface of the magnetic disk
Is used. This magnetic head assembly is supported and movable by an actuator arm for positioning. In addition, the slider of the hard disk drive has a read / write converter for data acquisition and storage. Generally, a magnetic disk has two discontinuous zones. `` Landing zon
e) ”(or“ Contact Start / Stop Zone
The "CSS zone", abbreviated as "Stop Zone)", is the zone in which the slider is located while the hard disk drive is off and where the slider leaves when the hard disk drive is started. The "data zone" is the zone where the slider flies and reads / stores data by using a read / write head.

[0003] When the hard disk drive is powered on, a force sufficient to overcome the static or "stiction" force on the slider should be applied to the slider. Between takeoff and landing,
The slider is maintained so as to make substantially constant contact with the magnetic disk. The lubricant on the landing zone
It is important to reduce wear and resistance between takeoff and landing. The CSS test method is widely used for measuring static friction / wear resistance. This static friction is measured by repeatedly taking off and landing the magnetic head assembly until wear of the disk surface occurs. The measured data on the static friction is an important factor for estimating the life of the hard disk drive.

As the speed of magnetic disks increases,
Air contacting the surface of the magnetic disk lifts the slider away from the surface. During a hard disk read / write (R / W) operation, the magnetic head assembly is moved by the actuator arm to jump over the data zone without touching the magnetic disk. However, during R / W operation,
The magnetic head assembly occasionally contacts the disk. Most of these in-flight contacts are the result of collisions between the slider and media roughness, corrosion products, or other contaminant particles.
The lubricant on the data zone minimizes disk wear and damage due to these in-flight contacts, but increases flying stiction between the magnetic head assembly and the disk surface. In addition, a protective layer of diamond-like carbon is required to prevent contact damage.
Sputter deposited on magnetic disk with thickness of 00 Angstroms. A lubricant layer is then formed over the overcoat layer to a thickness of about 20 angstroms. Generally, the lubricant layer has a combined lubricant layer that bonds to the overcoat layer and a free lubricant layer on the combined lubricant layer. A typical thickness of the combined lubricant layer is about 4-8 Angstroms, and a typical thickness of the free lubricant layer is 12-16 Angstroms.

In a hard disk drive having a conventional thin film head, a typical flying height of a slider is about 2
Microinch (about 500 angstroms).
However, current magnetoresistance (magneto-resistive,
In a heart disk drive having an MR) head, the flying height of the slider is about 1 microinch (about 2
50 Angstroms). Therefore, the pressure between the slider and the disk is further subatmospheric, forcing a reduced pressure air bearing design. Therefore, the lubricant on the disk surface is easily adsorbed to the slider, and this will increase the flying stiction of the magnetic head assembly.

US Pat. Nos. 4,960,609 and 4,642.
No. 246 and No. 503478 each disclose an inert gas plasma, heating and ultraviolet irradiation method for forming a lubricant layer on a disk. By using the above method in the prior art, high temperatures (35
C) It is possible to pass the CSS test of the hard disk in humid (80% RH). This is because the thickness of the free lubricant layer on the data zone according to the prior art has been reduced. Therefore, the floating static friction of the magnetic head assembly on the data zone is clearly reduced. However, unfortunately, the thickness of the free lubricant layer on the landing zone is likewise reduced. This will result in wear of the disk surface. To solve this problem, US Pat.
No. 900 proposes a magnetic disk having a zoned lubricant thickness.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk having different groups of zones of varied lubricant layer thickness in order to reduce the floating static friction on the surface of the magnetic disk.

The present invention also provides a method for forming lubricant layers of different thicknesses on separate zones of a magnetic disk of a hard disk without heating, inert gas plasma, and ultraviolet or electron beam irradiation. The task is to provide

[0009]

The present invention for solving the above-mentioned problems has the following requirements.

(1) A method of bonding a lubricant onto a magnetic disk of a hard disk drive, wherein the atmosphere conditions of a sputtering method having a plurality of gas species are controlled,
Covering the landing zone of the magnetic disk with a first mask, exposing the data zone of the magnetic disk, forming a protective film on the data zone of the magnetic disk by sputtering, removing the first mask, Changing the atmosphere conditions of the sputtering method, covering the data zone of the magnetic disk with a second mask, and exposing the landing zone of the magnetic disk,
Forming another protective film on the landing zone of the magnetic disk by sputtering, removing the second mask, and applying a lubricant on the entire surface of the magnetic disk including the landing zone and the data zone of the magnetic disk Applying a lubricant to a magnetic disk of a hard disk drive, comprising a step of forming a lubricant layer having a combined lubricant layer and a free lubricant layer.

(2) The method according to (1), wherein the plurality of gas species include hydrogen, nitrogen and argon, and the lubricant is bonded to the magnetic disk of the hard disk.

(3) The method according to (1), wherein the plurality of gas species include methane and argon.

(4) The method according to (1), wherein the plurality of gas species include methane, nitrogen, and argon.

(5) The thickness of the lubricant layer is the same on the landing zone and the data zone of the magnetic disk, but the thickness of the combined lubricant layer is different on both zones. The method for bonding a lubricant onto a magnetic disk of a hard disk according to (1).

(6) The thickness of the lubricant layer is different on the magnetic disk and on the data zone, but the thickness of the combined lubricant layer is the same on both zones.
3. A method for bonding a lubricant onto a magnetic disk of a hard disk according to 1.

(7) The method according to (1), wherein the thickness of the lubricant layer and the thickness of the combined lubricant layer are different on the landing zone and the data zone of the magnetic disk. A method of combining lubricant on the magnetic disk of a hard disk.

(8) A method of forming a protective film layer on a group of separate zones of a magnetic disk of a hard disk drive. Forming a first protective film layer on the surface of the magnetic disk , changing the atmospheric conditions of the sputtering method, and forming a second protective film layer on the remaining surface of the magnetic disk.
The protective film layer is formed of, and the magnetic disk disk
Apply lubricant to the entire surface of the
A step of forming a lubricant layer having a lubricant on a magnetic disk of a hard disk drive ;
How Ru bound a lubricant to.

(9) A lubricant is combined on the magnetic disk of the hard disk drive according to (8), wherein the plurality of gas species include hydrogen, nitrogen and argon.
How to Ru is.

(10) A lubricant is bonded on the magnetic disk of the hard disk drive according to (8), wherein the plurality of gas species include methane and argon.
How to.

(11) The plurality of gas species are methane,
Lubricant on the magnetic disk of the hard disk drive according to the above (8), which contains nitrogen and argon.
Coupled to form Ru way.

[0021] (12) the atmosphere how conditions Ru bound lubricant on a magnetic disk of a hard disk drive according to the above (8), a plurality of gas species volume.

[0022] (13) the atmosphere how conditions Ru bound lubricant on a magnetic disk of a hard disk drive according to the above (8), a flow rate of said plurality of gas species.

According to the present invention, a protective film layer having distinct zones of different composition is provided by using distinct masks under different sputtering conditions.
Sputtered first on the disk surface. Next, a lubricant layer is uniformly coated on this protective film layer. Part of the lubricant is bonded to the protective film layer to form a bonded lubricant layer, and since the thickness of the bonded lubricant layer is related to the properties of the protective film layer, it is zoned. A free lubricant layer having a variable thickness results. This free lubricant layer is formed from the remaining lubricant. The zoned lubricant of the present invention is therefore one that reduces flying stiction.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments. However, these embodiments do not limit the present invention in any way.

FIG. 1 is a diagram showing the structure of a hard disk drive having a magnetic disk and a magnetic head assembly, and FIG. 2 is a sectional view of the magnetic disk showing the relationship between a protective film layer and a lubricant layer.

As shown in FIG. 1, a magnetic disk 10 of a hard disk drive has a landing zone 11 on its inner diameter for landing and takeoff of a read / write head 21 and a rest zone on the disk. The data zone 12 is located at The read / write head 21 is supported by an actuator arm 20 for its movement. FIG. 2 shows a cross-sectional view of the magnetic disk 10. The magnetic disk 10 has a magnetic substrate 13, a protective film layer 14 formed by sputtering, and a lubricant applied on the protective film layer 14. This includes the lubricant layer 15 formed as a result. Then, the lubricant layer 15
Has a combined lubricant layer 151 and a free lubricant layer 152 located on the combined lubricant layer 151. In the combined lubricant layer 151, the lubricant is a lubricant with respect to the protective film layer. Is covalently bonded.

The floating static friction of the read / write head 21 is greatly related to the thickness of the lubricant layer 15. Further, the thickness of the lubricant layer 15 also depends on the chemical properties and thickness of the protective film layer 14. The present invention is directed to providing a protective overlayer 14 having separate zones, each having a different chemistry and thickness. According to the present invention, the chemistry and thickness of the overcoat layer 14 are:
It is different on the landing zone 11 and the data zone 12 of the magnetic disk 10. Lubricant layer 15
The thickness of the lubricant layer 15 depends on the chemistry and thickness of the protective film layer 14 in relation to the thickness of the read lubricant /
As a result, it is suitable for reducing the floating static friction of the write head 21.

The chemical properties and thickness of the protective film layer 14
In order to be different on distinct zones (eg, landing zone and data zone), the conditions for sputtering of overcoat layer 14 should be controllable, and multiple masks are used. Can be Next, a lubricant layer 15 is coated on the protective film layer 14.
Then, the combined lubricant layer 15 for reducing floating static friction is provided.
1 and the free lubricant layer 152 are finally formed. The method for bonding the lubricant to the magnetic disk 10 according to the present invention includes the following steps: a controlling the atmosphere conditions of the sputtering; b covering the landing zone 11 of the magnetic disk 10 with a mask and using the data zone. Exposing 12; c forming a protective film on the data zone 12 of the magnetic disk 10 by sputtering; d removing the mask for covering the landing zone 11; e separating the data zone 12 of the magnetic disk 10 Covering with the mask and exposing the landing zone 11, f forming another protective film on the landing zone 11 of the magnetic disk 10 by sputtering, g removing the mask from the data zone 12, and h Landing zone of the magnetic disk 10 A lubricant is applied on the entire surface of the magnetic disk, including the magnetic disk 11 and the data zone 12.

The order of the steps b to d and steps e to g can be changed without affecting the result of the present invention.

Although not particularly limited, examples of the lubricant that can be used in the present invention include perfluoropolyether (PFPE) having at least one polar or reactive terminal group. Examples of the solvent used for applying the lubricant include fluorocarbon solvents having a boiling point of 70 ° C. or less and having 5 to 7 carbon atoms, but are not limited thereto. In addition, as the protective film, DC or R using Ar, N ₂ , H ₂ or alkane gas and a graphite target is used.
Amorphous carbon formed by F sputtering can be exemplified, but is not limited thereto.

The combined lubricant layer 151 and the free lubricant layer 152
Since the thickness ratio is related to the chemical properties and thickness of the protective film layer 14, the sputtering atmosphere conditions should be controllable. The sputtering atmosphere conditions include the types and volumes of gases such as argon (Ar), hydrogen (H ₂ ), nitrogen (N ₂ ), and methane (CH ₄ ). Desirable atmospheric conditions for sputtering are selected from experiments described below.

Table 2 lists the conditions of the eight control variables of the method for bonding a lubricant to a magnetic disk according to the present invention. All control variables in the experiments of the present invention are described as follows: The control variable A represents the volume ratio of hydrogen; 2. control variable B represents the volume ratio of nitrogen; 3. Control variable C represents the power of the sputtering; The control variable D is a gas flow rate (unit: s) of a mixed gas in which hydrogen, nitrogen, and argon are mixed in their volume ratios.
ccm), 5. 5. The control variable E represents the residence time of the magnetic disk retained in the lubricant. 6. The control variable F represents the discharge speed of the lubricant applied on the magnetic disk. 7. Control variable G represents when the coated magnetic disk has been purged into nitrogen; The control variable H represents the concentration of the lubricant.

The total volume ratio of hydrogen, nitrogen and argon is 100%. Also, the discharge rate is the rate at which the solvent level falls during lubricant application.

In the manufacturing process in the experiment, the Ni-P plated Al substrate (Al-Mg substrate) was first textured with diamond slurry, washed, laser textured, and finally washed, and then manufactured by Intervac. DC disk spatter made by Int
ervec) to form a protective film layer (protective film layer structure: Cr / Co
CrPtTa / C: H ₂ (or N ₂ or N ₂ + H ₂ ))
And finally, a lubricant Z-DOL (Montedison)
(Montedison)) as a solvent, C ₆ F ₁₄ (PF50
60), using a gravity drain disk louver manufactured by San Jose Technology Inc.
n disk luber made by San Jose Technology) and applied on the protective film layer to form a lubricant layer. Here, lubrication is applied by first placing the disk in a tank, then filling the tank with a lubricant solution of a predetermined concentration (eg, 0.1% lubricant and 99.9% solvent), and the solution After the disk is completely immersed in the solution, the solution is drained from the tank at a constant speed and the lubricant is left on the disk by evaporation of the solvent.

Table 3 lists the experimental results, that is, the thickness of the combined lubricant layer on the discriminated zones (eg, the landing zone and the data zone) in the two magnetic disks. Under different conditions of the controlled variables. For each disk, two measurements were performed at different positions in the ID zones named ID1 and ID2, and two measurements were performed at different positions in the MD zones named MD1 and MD2 (accordingly. , For disk 1 shown in Table 3
The measurement results at D1, ID2, MD1, and MD2 are the ID1, ID2, MD1, and MD2 for disk 2.
It is completely independent of the measurement results in. ). According to the experimental results shown in Table 3, as the capacity of hydrogen (H ₂ ) and the concentration of lubricant increase, a thicker bonded lubricant layer grows. Evaluating the thickness of the combined lubricant layer is to measure the signal-to-noise ratio (S / N) of the combined lubricant. For a given number of repeated measurements of the combined lubricant thickness, the index divided by the average by the standard deviation (σ) means the S / N ratio of the combined lubricant thickness.

For example, for four measured bonded lubricants, the S / N ratio is calculated as follows:

[0037]

[Table 1]

[0038]

(Equation 1)

In Table 3, the measured S / N ratios are shown in the last column, for example, the first three S / N ratios.
The ratios 15.07, 13.66 and 14.38 and their tenth to twelfth S / N ratios of 1
7.62, 16.78 and 16.28 were measured when the volume ratio of hydrogen was 10%. Table 4
Is the average of the S / N ratio group under one condition of the control variable, for example, 15.63 which is the first value in the table is the S / N ratio group when the hydrogen volume ratio is 10% ( 15.0
7, 13.66, 14.38, 17.62, 16.78
And 16.28). The lubricant concentration is
It is clear that the different conditions give the largest variance in the S / N ratio average. On the other hand, the control variables
The hydrogen and nitrogen volume ratio, sputtering power, gas flow rate and nitrogen purge clearly affect the average S / N ratio variance.

FIG. 3 shows a graph of the S / N variation for all control variables under these different conditions. From these results, a preferable control condition can be selected to obtain a larger S / N ratio of the magnetic disk, that is, a thicker combined lubricant layer and smaller flying stiction are ensured. Since the concentration of the lubricant causes the largest fluctuation of the S / N ratio of the magnetic disk, an additional 2% of 0.06% and 0.18% of the lubricant is used.
One concentration was used in the experiment. The results of this experiment are shown in FIGS. The condition of the control variable that gives the maximum signal-to-noise ratio, ie, A3B3C1D3E2F2G1H2, is
It is selected as a preferable production condition of the present invention. By using these manufacturing conditions, as shown in Table 5, the S / N ratio of the present invention is improved by 80% over that of the prior art.
Therefore, by combining the use of the mask and the control of the sputtering condition of the present invention, the protective film layer 14 having the different zone groups having different thicknesses can be formed on the magnetic disk 10. Thus, after the coating of the lubricant layer 15, the thickness of the combined lubricant layer 151 will be different in these distinct zones, and the same will occur for the free lubricant layer 152. This is the reason why the floating static friction is reduced.

According to the experimental results shown in FIGS. 6 and 7,
By changing the volume ratio of hydrogen, nitrogen and argon under the condition of a constant concentration of lubricant of 0.6% and a constant gas flow rate, the lubricant layer 15 can be formed without increasing the thickness of the combined lubricant layer. The thickness could be increased. Alternatively, as shown in FIG. 8, the thickness of the combined lubricant layer 151 can be significantly increased by increasing the volume of hydrogen and nitrogen under a constant concentration of 0.18% lubricant. did it. In accordance with the method of the present invention, the thickness of the bonded lubricant layer 151 can be controlled without significantly changing the thickness of the lubricant layer by appropriately selecting the lubricant concentration. Similarly, the thickness of the lubricant layer 15 can be controlled by selecting another concentration of lubricant without significantly changing the thickness of the combined lubricant layer.

Table 6 shows the combined lubricant layer 15 of the lubricant layer 15.
3 shows the results of an experiment using the method of the present invention, in which the thickness and the volume ratio of 1 were measured in the landing zone and the data zone of the magnetic disk 10. It should be noted that the thickness and volume ratio of the bonding lubricant layer 151 can be controlled within a preferable range. Therefore, according to the present invention: 1. Having a lubricant layer of the same thickness over the landing zone and the data zone, but having a different thickness of the combined lubricant layer due to starvation of both zones; 2. having a different thickness of the lubricant layer on the landing zone and the data zone, but having the same thickness of the combined lubricant layer on both zones; and Having a different thickness of the lubricant layer on the landing zone and the data zone, and having a different thickness of the combined lubricant layer on both zones.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

The present invention provides a magnetic disk having a distinct zone group of lubricant layers of different thicknesses to reduce flying static friction on the disk surface.
In addition, the present invention also forms lubricant layers having different thicknesses on distinct zones of a magnetic disk of a hard disk drive without heating, inert gas plasma, and ultraviolet or electron beam exposure. Provide an easy way.

The above-described method of bonding a lubricant onto a magnetic disk is a preferred embodiment of the present invention only for the purpose of describing the present invention, and is intended to limit the limitations and scope of the present invention. It should be noted that this is not the case. Various modifications and alterations that fall within the scope of the invention will be apparent to those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a hard disk drive having a magnetic disk and a magnetic head assembly.

FIG. 2 is a cross-sectional view of a magnetic disk illustrating a relationship between a protective film layer and a lubricant layer.

FIG. 3 is a graph of S / N variation for all control variables under different conditions.

FIG. 4 is a graph of S / N fluctuations regarding other control variables when the lubricant concentration is fixed at 0.06%.

FIG. 5 is a graph of S / N fluctuations regarding other control variables when the lubricant concentration is fixed at 0.18%.

FIG. 6 is a graph showing the effect of the sputter gas composition on the thickness of the combined lubricant layer.

FIG. 7 is a graph showing an influence of a sputtering gas composition on a lubricant layer thickness.

FIG. 8 is a graph showing the influence of the lubricant concentration and the sputter gas composition on the thickness of the combined lubricant layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic disk 11 Landing zone 12 Data zone 13 Magnetic base material 14 Protective film layer 15 Lubricant layer 151 Bonded lubricant layer 152 Free lubricant layer 20 Actuator arm 21 Read / write head

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-150300 (JP, A) JP-A 8-227519 (JP, A) JP-A 8-36744 (JP, A) JP-A-1- 319128 (JP, A) JP-A-4-32021 (JP, A) JP-A-62-9717 (JP, A) JP-A-63-209025 (JP, A) JP-A-2-239425 (JP, A) JP-A-1-154378 (JP, A) US Patent 5,650,900 (US, A) US Patent 6,110,330 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/84 G11B 5 / 725

Claims (13)

(57) [Claims] 1. A method of bonding a lubricant onto a magnetic disk of a hard disk drive, comprising controlling an atmospheric condition of a sputtering method having a plurality of gas species, and covering a landing zone of the magnetic disk with a first mask. And exposing a data zone of the magnetic disk, forming a protective film on the data zone of the magnetic disk by sputtering, removing the first mask, changing an atmospheric condition of the sputtering method, Covering the data zone with a second mask, exposing the landing zone of the magnetic disk, forming another protective film on the landing zone of the magnetic disk by sputtering, removing the second mask, and The landing zone and data zone of the magnetic disk No, the lubricant was coated on the entire surface of the magnetic disk, bonded lubricant layer and a lubricating on a magnetic disk of a hard disk drive and having a process group for forming a lubricant layer having a free lubricant layer How to combine the agents. 2. The method according to claim 1, wherein the plurality of gas species include hydrogen, nitrogen, and argon. 3. The method as claimed in claim 1, wherein the plurality of gas species include methane and argon. 4. The method according to claim 1, wherein the plurality of gas species include methane, nitrogen and argon. 5. The thickness of the lubricant layer is the same on the landing zone and the data zone of the magnetic disk, but the thickness of the combined lubricant layer is different on both zones. 2. A method for bonding a lubricant onto a magnetic disk of the hard disk according to 1. 6. The hard disk according to claim 1, wherein the thickness of the lubricant layer is different on the magnetic disk and on the data zone, but the thickness of the combined lubricant layer is the same on both zones. To combine lubricant on magnetic disks. 7. The hard disk drive according to claim 1, wherein the thickness of the lubricant layer and the thickness of the combined lubricant layer are different on a landing zone and a data zone of the magnetic disk. A method of bonding a lubricant onto a magnetic disk. The magnetic disk of 8. A hard disk drive
A method of Ru bound lubricant on to control the ambient conditions of the sputtering method with a plurality of gas species, the first protective layer is formed on part of the surface of the magnetic disk, the sputtering change the ambient conditions of the law, the second protective layer is formed on the remaining surface of the magnetic disk, and a lubricant is applied on the entire surface of the magnetic disk
Layer having lubricated and free lubricant layer bonded together
How Ru bound lubricant on a magnetic disk of a hard disk drive and having a process group to form a. 9. The method wherein the plurality of gas species, hydrogen, Ru is bound lubricant on a magnetic disk of a hard disk drive of claim 8 is intended to include nitrogen and argon. 10. A method wherein the plurality of gas species, that Ru to bind the lubricant on the magnetic disk of the hard disk drive of claim 8 is intended to include methane and argon. Wherein said plurality of gas species, methane, nitrogen and lubricant coupled to form <br/> Ru method on a magnetic disk of a hard disk drive of claim 8 is intended to include argon. 12. The method of Ru bound lubricant on a magnetic disk of a hard disk drive of claim 8 wherein the atmospheric condition is a plurality of gas species volume. 13. The method of Ru bound lubricant on a magnetic disk of a hard disk drive of claim 8 wherein the atmospheric condition is the flow rate of the plurality of gas species.