JPH10208442A - Magnetic disc device, head disc assembly and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a head disc assembly(HDA) by which a magnetic disc device with the improved reliability can be obtained. SOLUTION: When an HDA is assembled by incorporating components in a housing, an atmosphere in a vacuum glove box 1 is made to satisfy at least one condition which is selected among a condition that the content of organic silicone existing in the form of gas is not higher than 0.2μmol/m<3> in terms of silicon atoms, a condition that the content of organic tin existing in the form of gas is not higher than 50 pico-mol/m<3> in terms of tin atoms and a condition that the total content of all the organic gases is not higher than 20μmol/m<3> in terms of carbom atoms by gas which is made to flow through a silica gel adsorbing layer 2, a molecular sieves adsorbing layer 3, an active carbon adsorbing layer 4 and a cooled molecular sieves adsorbing pipe 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device used for a storage device of a computer, a head disk assembly (hereinafter referred to as HDA) used for the magnetic disk device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, in a magnetic disk drive, a floating gap between a magnetic head and a magnetic disk is minimized in order to increase recording density, and a magnetic disk drive having a floating gap of 0.1 μm or less is being developed. When the flying gap between the magnetic head and the magnetic disk is minimized in this way, a failure occurs due to a small amount of organic gas generated from inside the HDA. For example, when the apparatus is stopped, an organic gas enters between the magnetic disk and the magnetic head and liquefies, and the magnetic head is attracted to the magnetic disk so that the spindle cannot be rotated. The attitude of the magnetic head collapses due to the invasion of minute foreign matter that has come in between, and the organic gas is denatured due to the temperature rise caused by the contact between the magnetic head and the magnetic disk. In some cases, the gas is converted into particles and floating dust is generated, causing a collision between the magnetic head and the magnetic disk and damage to the magnetic disk.

Conventionally, as a countermeasure, a gas adsorbent such as activated carbon is provided inside the HDA in order to increase the cleanliness inside the HDA. Also, a dust removal filter has been installed inside the HDA. Furthermore, as described in JP-A-5-234352, a thin film of an adhesive substance is provided inside the HDA to attach floating minute foreign matters that cannot be removed by the above-mentioned dust removal filter.

[0004]

The prior art in which the above-mentioned activated carbon is installed has a limit in the amount of activated carbon adsorbed.
Activated carbon is generally easy to adsorb high molecular weight organic gas such as dioctyl phthalate, xylene, benzaldehyde, etc., but ethanol (boiling point: 78 ° C.), acetone (boiling point: 5
6 ° C.), isopropyl alcohol (boiling point: 82 ° C.), methylene chloride (boiling point: 40 ° C.), and other components having a boiling point of 100 ° C. or less (hereinafter referred to as low boiling point components). When ethanol, methylene chloride, or the like is used as a CFC substitute detergent, the ethanol concentration may reach tens of ppm even in HDA to which activated carbon is attached. These low-boiling organic gases cause sticking in HDA in which the floating gap is minimized. In addition, it is becoming difficult to find a space for a large amount of activated carbon due to downsizing.

[0005] Further, the prior art in which the above-mentioned dust removing filter is installed has a problem that not all foreign substances are supplemented. For example, very small foreign matter passes through the filter, and gaseous substances are not captured.

Further, the above-mentioned prior art in which a thin film of an adhesive substance is provided has a problem that floating fine foreign matter can be attached and removed, but gaseous substances cannot be captured.

[0007] In the HDA, there are an organic gas generated from the device component itself, a trace amount of organic gas invading from the assembling environment, an organic gas adsorbed from the environment to the component incorporated in the HDA, and the like. As described above, when the HDA is stopped, these organic gases enter between the magnetic disk and the magnetic head and liquefy, causing the magnetic head to be attracted to the magnetic disk, making it impossible to rotate the spindle or preventing the magnetic disk from operating during the operation of the HDA. The magnetic head denatures and solidifies between the magnetic heads and causes destruction of the magnetic disk or head crash.

A first object of the present invention is to provide a method of manufacturing an HDA for obtaining a magnetic disk drive with improved reliability. A second object of the present invention is to provide an HDA used for such a magnetic disk device.
A third object of the present invention is to provide a magnetic disk drive with improved reliability.

[0009]

Means for Solving the Problems In order to achieve the first object, the method of manufacturing an HDA according to the present invention is a method for assembling an HDA by incorporating components such as a magnetic disk and a voice coil motor into a housing. organosilicone amount of 0.2 micromoles / m ³ the following conditions with a silicon atom in terms present in gaseous form, 50 pmol / m ³ the following conditions and total organic by organotin weight tin atoms in terms present in the gaseous The process is performed in an atmosphere that satisfies at least one condition selected from the group consisting of a gas amount of 20 micromol / m ³ or less in terms of carbon atoms.

In this atmosphere, it is preferable that the amount of the organic silicone satisfies the above three conditions. The amount of the organic silicone has a greater effect on the adhesion of the magnetic head and the like than the amount of the organic tin and the amount of the total organic gas. Next important is the amount of organotin. Therefore, it is preferable that the amount of the organic silicone and the amount of the organic tin both satisfy the above conditions. Of course, it is most preferable that all three conditions are satisfied.

The atmosphere may include at least one of a gas adsorbing means composed of a gas adsorbing material such as activated carbon or a chemical filter, an organic gas decomposing means using ultraviolet rays or ozone, and a low-temperature cooling means. It is preferable that the above conditions be satisfied by the gas that has passed.

In order to achieve the first object,
The method for manufacturing an HDA according to the present invention includes the steps of incorporating a component such as a magnetic disk and a voice coil motor into a housing.
Before assembling DA, before the assembly, the amount of organosilicone present in gaseous state is 0.2% in terms of silicon atoms.
Micromol / m ³ or less, the condition that the amount of organotin existing in a gaseous state is 50 picomoles / m ³ or less in terms of tin atoms, and the total amount of organic gas is 20 micromol / m ^{2 in} terms of carbon atoms.
After saving the component in an environment that satisfies at least one condition m ³ selected from the group consisting of the following conditions, in which as incorporated into the housing. Save is 2
It is preferably at least one hour, more preferably at least one day. Further, since the storage efficiency is too low for long-term storage, storage for 7 days or less is preferable, and storage for 3 days or less is more preferable.

[0013] In this atmosphere, it is preferable that the amount of the organic silicone satisfies the condition among the three conditions as described above, and that the amount of the organic silicone and the amount of the organic tin both satisfy the above condition. More preferably, all three conditions are satisfied.

Before the above parts are stored in the above environment, the parts are heated to a temperature of more than 100 ° C. in a vacuum of 10 ⁻⁴ Pa or less.
It is preferable to heat at the following temperature.

Further, in order to achieve the second object,
The HDA according to the present invention is characterized in that the atmosphere in the housing is in an operating state at room temperature, and the amount of the organic silicone present in a gaseous state is 0.2 μmol / m ³ or less in terms of silicon atoms.
At least one selected from the group consisting of a condition in which the amount of organotin present in a gaseous state is 100 picomoles / m ³ or less in terms of tin atoms and a condition in which the total amount of organic gases is 40 micromoles / m ³ or less in terms of carbon atoms. It is designed to satisfy the conditions.

In this atmosphere, it is preferable that the amount of the organic silicone satisfies the condition among the three conditions as described above, and that the amount of the organic silicone and the amount of the organic tin both satisfy the above condition. More preferably, all three conditions are satisfied.

Further, in order to achieve the third object, a magnetic disk drive of the present invention is configured to have at least one HDA.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Example 1 An HDA was prototyped by controlling the organic gas in the assembly environment. FIG. 1 shows a schematic diagram of a glove box used for assembly. In the stainless steel vacuum glove box 1,
Nitrogen gas was passed through a silica gel adsorption layer 2, a molecular sieves adsorption layer 3, and an activated carbon adsorption layer 4, and then supplied through a molecular sieves adsorption tube 5 cooled with liquid nitrogen.
Prior to use, the inner wall of the vacuum glove box 1 was sufficiently wiped, and the glove 6 was washed and dried. Glove 6
Was attached to the vacuum glove box 1, and the nitrogen gas treated as described above was allowed to flow for several days while heating with the heater 7 inside. Further, degassing and inflow of the nitrogen gas treated as described above were repeated several times, and a sampling pipe was inserted to the working portion to sample the gas appropriately.

The concentration of the organic silicone in the sampled gas is determined by GC using the activated carbon adsorption concentration method.
-MASS was measured by (gas chromatography-mass spectrum scan copy) (0.2 micromoles / m ³ of silicon atoms terms) 1 ppb octamethylcyclotetrasiloxane converted was less. The organotin concentration was 50 picomoles / m ³ ) or less in terms of tin atom as measured by ICP-MASS by a solvent absorption method. The total amount of organic gas (total amount including the organic silicone and organotin) was measured by a gas chromatograph using an air sampling-cryofocus method.
70 ppb in terms of ethyl acrylate (2 in terms of carbon atoms)
0 micromol / m ³ ). The method for measuring each gas concentration described below is the same as above unless otherwise specified.

All parts used for HDA assembly are 80 ° C, 1
After vacuum baking under the condition of 0 ^-4 Pa, it was placed in a container treated in the same way and transferred to a vacuum glove box, where it was left and stored in a nitrogen gas stream treated as described above for several days.

In the HDA assembly, a head stack assembly (hereinafter, referred to as HSA) was first prepared. After caulking the head gimbal assembly to the carriage,
A printed circuit was attached, and a head lead wire and a voice coil motor (hereinafter, referred to as VCM) coil wire were soldered. Next, attach the pivot and HSA
And The spindle shaft was attached to the base in the housing, and the magnetic disk was assembled on the spindle shaft. HSA was loaded into this, and VCM was incorporated. Next, attach activated carbon and silica gel to the base of the housing, cover the housing, seal it,
It was created. A control board was attached to the HDA, a plurality of the boards were placed in a housing, and connected to a power supply to obtain an array-type magnetic disk drive.

The magnetic disk is composed of a 10-μm thick Ni—P underlayer, a 28-nm thick Cr film intermediate layer, and a 28-nm thick Co on a 3.5-inch aluminum alloy disk.
A CrTa alloy magnetic layer, a carbon protective film layer having a thickness of 26 nm, and a perfluoroalkyl ether-based lubricating layer having a thickness of 2 nm were used. The head is Al ₂ O ₃
A slider in which a coil portion is formed by a thin film process on a slider that is a sintered body of TiC and TiC was used. The rotation speed of the magnetic disk drive is 6,300 rpm, and the flying height of the head at the rated rotation speed is 30 nm.

After assembling, the HDA was operated at room temperature and the internal gas was analyzed. As a result, the organic silicone concentration was 1 ppb or less (0.2 micromol / m ^{3 in} terms of silicon atoms) in terms of octamethylcyclotetrasiloxane. The total amount of organic gas was not more than 100 ppb in terms of ethyl acrylate (30 μmol / m ^{3 in} terms of carbon atoms). After this measurement, the HDA was heated to 65 ° C. for 3 hours, and an adsorption tube having cloth activated carbon placed at the breathing port was installed.
1 m ³ of gas was sucked in, and the amount of organotin was measured.
The organic tin concentration was 95 picomoles / m ³ in terms of tin atoms. The capacity of HDA is about 500 cc. When the HDA is operated at room temperature, the internal temperature is 40
Since the temperature does not reach 65 ° C. from about 45 ° C. to about 45 ° C., the organotin concentration in the operating state at normal temperature is equal to or lower than this value.

FIG. 2 shows the result of evaluating the reliability of HDA by an operation test in a random mode seek under a high temperature environment. FIG. 2 is a diagram illustrating the adhesive force with respect to the operating time in the magnetic disk device. 500 of this embodiment shown by a in FIG.
The adhesive strength after running for 0 hours is about 1.7 g, which hardly changes from the initial value.

<Comparative Example 1> As a comparative example, the same H
The DA was assembled and prototyped in a normal clean room where the organic gas in the environment was not controlled. The organic silicone concentration in the assembly environment is 5 ppb in terms of octamethylcyclotetrasiloxane (1 micromol / m ^{3 in} terms of silicon atoms), and the organotin concentration is 200 in terms of tin atoms.
Picomoles / m ³ ) and the total amount of organic gas was 300 ppb in terms of ethyl acrylate (90 μmol / m ^{3 in} terms of carbon atoms).

After assembling, the HDA was operated at room temperature, and the internal gas was analyzed. As a result, the concentration of organic silicone was 10 ppb in terms of octamethylcyclotetrasiloxane.
(2 micromoles / m ^{3 in} terms of silicon atoms), and the total amount of organic gas was 1 ppm in terms of ethyl acrylate (290 micromoles / m ^{3 in} terms of carbon atoms). The organotin concentration measured in the same manner as in Example 1 was 250 picomoles / m ³ in terms of tin atoms.

FIG. 2B shows the change in the adhesive force in the same operation test as in Example 1. After 5000 hours, the adhesion increased and reached about 5 g.

When the magnetic disk after the test was obliquely irradiated with light and observed with a microscope, the magnetic disk of the comparative example showed a slight difference in density between the seek area and the non-seek area. No magnetic disk was observed. The lubricating film thickness of the magnetic disk of the comparative example was measured using a CF having a wave number of 1290 cm ^{-1 in} a micro Fourier transform infrared spectrum.
When quantified by the absorbance of the elastic bond, it was found that the non-seek area was reduced to 2 nm and the seek area was reduced to 1 nm by half.

[0029]

As described above, by controlling the organic gas in the environment for assembling the HDA or controlling the organic gas in the environment for storing the parts before assembly, or both, the adhesion of the magnetic head is reduced. Reduction can be achieved. Therefore, troubles such as a head crash due to this are eliminated, and the reliability of the manufactured HDA is improved. Further, by controlling the organic gas in the housing of the HDA, the reliability of the HDA is improved. Also, by incorporating such an HDA, a magnetic disk device with improved reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a glove box used for assembling an HDA according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a change in adhesive strength in an operation test of HDA.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum glove box 2 ... Silica gel adsorption layer 3 ... Molecular sieves adsorption layer 4 ... Activated carbon adsorption layer 5 ... Molecular sieves adsorption tube 6 ... Glove 7 ... Heater

Claims (6)

[Claims] 1. A head disk assembly manufacturing method for assembling a head disk assembly by incorporating at least parts including a magnetic disk and a voice coil motor into a housing.
Conditions in which the amount of organosilicone present in gaseous state is 0.2 μmol / m ³ or less in terms of silicon atoms, conditions in which the amount of organotin present in gaseous state is 50 picomoles / m ³ or less in terms of tin atoms, and total organic gas A method for producing a head disk assembly, wherein the method is performed in an atmosphere that satisfies at least one condition selected from the group consisting of 20 micromol / m ³ or less in terms of carbon atoms. 2. The method for manufacturing a head disk assembly according to claim 1, wherein the atmosphere is at least one selected from the group consisting of a gas adsorbing means constituted by a gas adsorbing material, an organic gas decomposing means, and a low-temperature cooling means. A method for manufacturing a head disk assembly, characterized in that the above conditions are satisfied by gas passed through one means. 3. A method of manufacturing a head disk assembly in which at least parts including a magnetic disk and a voice coil motor are incorporated in a housing to assemble a head disk assembly. 0.2 in conversion
Micromol / m ³ or less, the condition that the amount of organotin existing in a gaseous state is 50 picomoles / m ³ or less in terms of tin atoms, and the total amount of organic gas is 20 micromol / m ^{2 in} terms of carbon atoms.
after storage in an environment that satisfies at least one condition selected from the group consisting of m ³ the following conditions, method of manufacturing the head disk assembly, characterized in that incorporated within the housing. 4. The method of manufacturing a head disk assembly according to claim 3, wherein the temperature of the component exceeds a normal temperature under a vacuum of 10 ⁻⁴ Pa or less before the component is stored in the environment.
A method for manufacturing a head disk assembly, wherein the head disk assembly is heated at a temperature of 0 ° C. or less. 5. A head disk assembly in which parts including at least a magnetic disk and a voice coil motor are incorporated in a housing, wherein the atmosphere in the housing is an amount of organic silicone present in a gaseous state in an operating state at normal temperature. Is 0.2 micromol / m ³ or less in terms of silicon atoms, the organic tin content in gaseous condition is 100 picomoles / m ³ or less in terms of tin atoms, and the total organic gas content is 40 micromoles / m ^{3 in} terms of carbon atoms. A head disk assembly having an atmosphere satisfying at least one condition selected from the group consisting of mol / m ³ or less. 6. A magnetic disk drive comprising at least one head disk assembly according to claim 5.