JP2000339672A - Glass substrate material for information memory medium and method for processing glass ceramic substrate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make processing on a prescribed substrate excellent in smoothness and surface defectiveness by forming many tile-like protrusions having flat peak parts by fixation of diamond abrasive grains to a resin blank. SOLUTION: Primary lapping is executed by using a diamond pellet fixed with the diamond abrasive grains to a bond, such as resin, metal or vitrified bond, in order to obtain a surface condition adequate for secondary processing comparatively in a short time. The grain size of the diamond abrasive grains fixed to the diamond pellet is preferably #800 to #1500 in order to suppress the generation of scratches and cracks on the surface of a base plate material. After the primary lapping, the secondary processing involving fine grinding with a diamond pad is executed. The diamond pad forms the many tile-like protrusions having the flat peak parts. The tile-like protrusions are formed by fixing the diamond abrasive grains to the resin blank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium used in an information storage device. In this specification, an "information storage medium" is a fixed hard disk, a removable hard disk, a card hard disk used as a hard disk of a personal computer, or a disk-shaped information storage usable in a digital video camera / digital camera. Means medium and the like.

[0002]

2. Description of the Related Art In recent years, information storage devices such as a removable type and a card type have been studied with respect to a conventional fixed type information storage device, and they are in a practical stage, and applications of digital video cameras and digital cameras have begun to be developed. Due to such trends, the use of multimedia in personal computers and the spread of digital video cameras, digital cameras and the like have been rapidly advancing in recent years. In order to handle large-sized data such as moving images and voices, large-capacity information magnetic storage devices have been developed. Is required. To address this, information storage media must increase bit and track densities and reduce the size of bit cells to increase the areal recording density, while the magnetic head moves closer to the disk surface as the bit cells shrink. It is moving toward the use of near contact recording and further contact recording.

As described above, with the increase in the density of a magnetic recording device,
The strength and other physical properties (such as surface roughness) required for these information storage medium substrates have also become higher, and as a result, materials are shifting from aluminum alloys to glass ceramics and chemically strengthened glass. The processing method of these chemically strengthened glass materials and glass ceramic materials is generally constituted by three steps of primary processing → secondary processing → polishing. As for the primary processing, there are a processing using loose abrasive grains (SiC type) and a diamond pellet processing method using a lap method. Regarding secondary processing, several processing methods have been recently proposed for the purpose of improving the processing rate, improving the surface roughness, and shortening the polishing time. As a secondary processing method, a lapping method # 20 has been proposed.
The processing method using diamond pellets of 00 or more, the processing method using a single-sided single-sided resin or metal diamond wheel using a rotary method, and the processing method using an elid mechanism on a single-sided single-sided resin or metal diamond wheel using a rotary method were evaluated. Have been.

[0004] However, any of the processing methods has problems such as scratches on the substrate surface, grinding marks, suction marks due to suction for fixing the substrate material (single-sheet type), and variations in plate thickness. It is difficult to say that the processing method of glass substrates or glass ceramic substrates for information storage media can be used satisfactorily with the aim of shortening the processing time, reducing cost, and increasing accuracy. .

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a processing method suitable for a glass substrate material or a glass ceramic substrate material for an information storage medium in order to solve the above-mentioned drawbacks in the prior art. It is in.

[0006]

Means for Solving the Problems The present inventor has conducted intensive tests and researches in order to achieve the above object, and as a result, in the method of processing a glass substrate material or a glass ceramic substrate material for an information storage medium, the primary lapping process is performed. Lapping with diamond pellets such as resin, metal, vitrified, etc., and secondary processing with diamond pads eliminates surface smoothness and defects such as scratches, grinding marks, suction marks, etc. They have found that processing is possible, and have reached the present invention.

That is, the invention according to claim 1 is a method of processing a substrate material including a primary lapping process and a secondary processing, wherein the primary lapping process includes bonding of resin, metal, vitrified or the like with diamond abrasive grains. Characterized by lapping using fixed diamond pellets,
The secondary processing is a step of precision grinding with a diamond pad after the primary lap processing, wherein the diamond pad has a large number of tile-shaped protrusions having flat tops, and the tile-shaped protrusions are formed. 3. A method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium, characterized in that diamond particles are fixed to a resin-based material. In the processing, the particle size of the diamond abrasive fixed to the bond of resin, metal, vitrified, etc. is # 800 to # 15
The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to claim 1, wherein the diamond pellet is a Knoop hardness of the bond of the diamond pellet. Is 300x1
The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to claim 1, wherein the glass substrate material is within a range of 0 to 800 × 10 N / mm ² . The invention provides, in the secondary processing,
Diamond size of diamond pad is 1-15μm
The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to any one of claims 1 to 3, characterized in that: The Vickers hardness of the tile-shaped protrusion of the diamond pad is 5 × 10 to 40 × 10 N /
characterized in that it is in the range of mm ^2, a processing method of any glass substrate member information storage medium of one claim or glass-ceramic substrate material of claim 1 4,
According to a sixth aspect of the present invention, in the processing method, the surface roughness Ra (arithmetic average roughness) of the glass substrate material or the glass ceramic substrate material after the secondary processing is 50 to 800 °, Rp
(Maximum peak height) and Rv (maximum valley depth) are 300
6. The method according to claim 1, wherein the angle is up to 3000 °.
8. A method for processing a glass substrate material for an information storage medium or a glass ceramic substrate material according to any one of the above, wherein the invention according to claim 7 is a glass substrate material processed in the method for processing a glass substrate material. Is SiO ₂ —Al ₂ O
₃ -R ₂ O (where, R represents at least one selected from alkali metal elements), wherein the system is a chemically tempered glass, information storage as claimed in any one of claims 1 to 6 A method for processing a glass substrate material for a medium, wherein the glass ceramic substrate material to be processed is SiO ₂ —Al ₂ O ₃ —Li ₂ O in the method for processing a glass ceramic substrate material. The processing of the glass ceramic substrate material for an information storage medium according to any one of claims 1 to 7, characterized in that the glass ceramic substrate is an SiO ₂ -Al ₂ O ₃ -MgO-TiO ₂ -based glass ceramic. The invention according to claim 9, wherein the method for processing a glass substrate material or a glass ceramic substrate material is characterized in that the diamond pad has a diamond pad in secondary processing. The particle size is in the range of 1 to 15 μm,
The processing slurry has a ZrO content of 1.0 to 1.5 μm.
2-20% by weight of either ₂ or Al ₂ O ₃ abrasive
The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to any one of claims 1 to 8, characterized in that the material is contained. 10. A glass substrate material for an information storage medium or a glass ceramic substrate material processed by the method according to any one of 1 to 9. In this specification, Rp (maximum peak height) indicates the distance between the average line of the roughness curve and the peak of the maximum convex portion at the reference length of the substrate surface, and Rv (maximum valley depth) is The distance between the average line of the roughness curve and the valley bottom of the largest concave portion at the reference length of the substrate surface is shown.

The reason why the method of processing the glass substrate material for information storage medium or the glass ceramic substrate material of the present invention is limited as described above will be described below.

The method for processing a substrate material according to the present invention includes a primary lap processing and a secondary processing. First, in order to obtain a surface state suitable for secondary processing in a relatively short time, primary lap processing is performed using diamond pellets in which diamond abrasive grains are fixed to a bond of resin, metal, vitrified or the like. The particle size of the diamond abrasive grains fixed to the diamond pellet is preferably # 800 or more in order to suppress generation of scratches and cracks on the surface of the substrate material. In addition, the processing time becomes longer as the processing rate decreases and the processing time becomes longer, and at the same time, the grain size of the diamond abrasive grains is set to # 1500 in order to prevent clogging / blinding of the diamond abrasive grains.
The following is preferred. The Knoop hardness of the diamond pellet bond used in the primary lapping process is 3 from the viewpoint of processability.
It is preferably in the range of 00 × 10 to 800 × 10 N / mm ² , and 500 × 10 to 700 × 10 N / mm ²
Is more preferably within the range. Next, secondary processing will be described. The secondary processing according to the present invention is a step of performing precision grinding with a diamond pad after the primary lap processing. The diamond pad has a large number of tile-shaped protrusions having flat tops, and it is most important in the present invention that the tile-shaped protrusions are formed by fixing diamond abrasive grains to a resin material. This is the point of the invention.
After primary lapping of glass ceramic substrate material,
As secondary processing, for example, by performing fine grinding with a diamond pad having a tile-shaped protrusion in which diamond abrasive grains are fixed to a resin material, for example, surface texture suitable for plating with Ni-P or the like. A ground surface can be obtained. When the glass or glass ceramic substrate material is polished using free abrasive grains, after the primary lap processing, as a secondary processing, a tile-shaped convex in which diamond abrasive grains are fixed to a resin material. By performing precision grinding with a raised diamond pad, it is possible to finish a polished surface with good smoothness in a short time in subsequent polishing using loose abrasive grains. On the other hand, when directly polished after lapping, it is difficult to finish a polished surface with good smoothness, or requires a very long processing time. Further, even in the case of the rotary diamond wheel system, the polished surface obtained is not sufficient. The tile protrusion has a flat top. The flat top of the tile-shaped protrusion is subjected to fine grinding by forming a large number of the tile-shaped protrusions on one surface of the diamond pad to form a virtual plane. It is preferable that a large number of the tile-shaped protrusions are laid on one surface of the diamond pad with a gap of less than about 1 mm in order to obtain a good precision grinding effect. In addition, at the time of precision grinding, the diamond pad was subjected to a groove processing with a width of about 1 to 10 mm for each of a plurality of tile-shaped protrusions so that the grinding fluid was evenly distributed and the grinding chips were smoothly discharged. Are preferred. As the tile-shaped raised resin-based material, polyurethane-based, phenolic-based,
A material such as a melamine resin can be used. The Vickers hardness of the tile-shaped protrusion of the diamond pad used in the secondary processing of the present invention is 5 × 10 to 40 × 10 N / m.
m ² , preferably 10 × 10 to 30
More preferably, it is within the range of × 10 N / mm ² .

When the diameter of the fixed diamond abrasive grains exceeds 15 μm, the target surface roughness cannot be obtained. When the diameter of the diamond pad is less than 1 μm, the cost of the processing time increases and the substrate material obtained is large. It becomes very expensive. The substrate surface roughness Ra (arithmetic average roughness) after being processed by the diamond pad composed of the diamond particle diameter is 50 to 800 °, Rp (maximum peak height) and Rv (maximum valley depth). Is 300-3
It is preferably in the range of 000 °.

A grinding liquid is used when processing with a diamond pad. In the present invention, a processing liquid is used together with a polishing liquid containing an abrasive of ZrO ₂ or Al ₂ O ₃ as a processing slurry in place of the grinding liquid. It is also possible to improve the rate and the surface smoothness. These abrasives may be any abrasive in the range of 1.0 to 1.5 μm for 3 to
It is preferable to process with a slurry containing 20 wt%.

The glass processed by these processing methods
Substrate material is SiO_Two―Al_TwoO_Three-R_TwoO (where R is al
At least one selected from potassium metal elements)
Chemically strengthened glass, SiO_Two―Al_TwoO_Three―Li_TwoO-based glass
Ceramics, SiO_Two―Al_TwoO_Three-MgO-TiO_Twosystem
Suitable for glass ceramics, especially SiO_Two―Al_Two
O_Three-MgO-CaO-Li_TwoO-Na_TwoO-ZrO_Two-Y
_TwoO_Three―TiO_Two-As _TwoO_ThreeChemically strengthened glass, SiO_Two―
Al_TwoO_Three―Li_TwoO-Na_TwoO-ZrO_Two-As _TwoO_ThreeSystematization
Chemically strengthened glass, SiO_Two―Al_TwoO_Three-MgO-ZnO
―Li_TwoOP_TwoO_Five―ZrO_Two-K_TwoO-Sb_TwoO_ThreeSystem gala
Ceramics, SiO_Two―Al_TwoO_Three-MgO-CaO
-BaO-TiO_Two-P_TwoO_Five-As_TwoO_ThreeGlass ceramic
Box, SiO_Two―Al_TwoO_Three-MgO-CaO-SrO
-BaO-TiO_Two―ZrO_Two-Bi_TwoO_Three-Sb_TwoO_ThreeSystem
Suitable for lath ceramic materials. Further contained
Speaking of the crystal phase, lithium disilicate, SiO_TwoSystem crystal (stone
English, cristobalite, tridymite, etc.), cordilla
Site, enstatite, titanium aluminum
Cium, spinel crystal ([Mg and / or Zn]
Al_TwoO_Four, [Mg and / or Zn]_TwoTiO_Fourand
Refers to the solid solution between these two crystals), forsterite,
Spodumene and a solid solution of these crystals are used as a crystalline phase.
Very suitable for glass ceramics containing
You.

[0013]

Next, a preferred embodiment of the present invention will be described. Tables 1 and 2 show the composition of the glass substrate material and the glass ceramic substrate material for the information storage medium processed by the processing method of the present invention, the state of the glass substrate material and the glass ceramic substrate material, and the Young's modulus and specific gravity of each material. , Vickers hardness (Hv). Tables 3 and 4 show Tables 1 and 2 respectively.
And 11 processing examples of the glass substrate material and the glass ceramic substrate material described in the above section, and the processing methods generally used at present as comparative processing examples. Examples of these working examples include the number of diamond pellets in the primary lap, the diamond particle diameter in the diamond pad in the secondary processing, the type and particle size and content of the processing slurry abrasive, the surface roughness Ra, Rv, As Rp and surface appearance, the presence or absence of scratches (small scratches) and pits (deep hole-shaped dents) are shown. Further, FIGS. 1 to 8 show micrographs (Nomarski micrographs or photographs by a surface defect inspection apparatus) of the appearance of each substrate surface obtained by the processing method of the present invention and the general processing method. Here, FIG. 1 is a Nomarski microscope photograph of the working example 5, and FIG. 2 is a photograph by the surface defect inspection device of the working example 5. FIG. 3 is a working example 1
0 is a Nomarski microscope photograph, and FIG. 4 is a photograph by the surface defect inspection apparatus of Working Example 10. FIG. 5 is a Nomarski microscope photograph of Comparative Working Example 1, and FIG. 7 is a Nomarski microscope photograph of Comparative Working Example 2, and FIG. 8 is a photograph of the Comparative Working Example 2 by a surface defect inspection apparatus.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

[0017]

[Table 4]

[0018]

[Table 5]

The working examples of the present invention each use a 3.5 "disk substrate, and the primary lapping work is a diamond pellet of # 800 to # 1500 using a 12B double-sided working machine (the Knoop hardness of the bond is 600 × 10N). / Mm
^{Using 2} ), processing was performed at a processing load of 100 to 250 g / cm ² and a processing rotation speed of 20 to 50 rpm. Next, as secondary processing, fine grinding was performed using a diamond pad having tile-shaped protrusions in which diamond abrasive grains having respective diamond particle diameters were fixed to a resin material. Here, a tile-like object having a dimension of 1.34 × 1.34 × 0.30 mm is laid with a gap of 0.50 mm to form a tile-like protrusion, and further, for each 11 × 11 tile-like protrusions, A diamond pad having a depth of 0.5 mm and a width of 2.0 mm was used. FIG. 9 shows the surface of the diamond pad on which the tile-shaped protrusions are laid. The Vickers hardness of the tile-shaped protrusion of this diamond pad is 2
It was 0 × 10 N / mm ² . The diamond pad, which has been subjected to a groove processing of about 1 to 10 mm, is attached to the upper and lower platens of a 12B double-sided processing machine, and the processing load is 100 to 250 g /.
cm ² , and the number of processing rotations is about 5 to 20 to 50 rpm.
Processing took 25 minutes.

As shown in Tables 3 and 4 and FIGS. 1 to 8, in the processing method of the present invention, the surface roughness after processing is remarkably improved as compared with the conventional processing method, and the substrate which has been regarded as a problem in the prior art is used. Since no scratches, pits, grinding marks and suction marks are generated on the surface, it is an excellent method for processing a glass substrate material for information storage media or a glass ceramic substrate material. In addition, the substrate material processed by the processing method of the present invention was capable of shortening the time required for polishing in a subsequent step and, at the same time, capable of obtaining a substrate having excellent smoothness.

[0021]

As described above, according to the processing method of the present invention, while eliminating the above-mentioned disadvantages of the prior art,
The processing of all glass substrates or glass ceramic substrates for information storage media is excellent in smoothness and surface defects, and at the same time, the cost of glass substrates or glass ceramic substrates for information storage media is excellent in cost reduction due to short processing time. A processing method can be provided.

[Brief description of the drawings]

FIG. 1 is a photograph of a substrate surface state by a Nomarski microscope of Working Example 5.

FIG. 2 is a photograph of a surface state of a substrate by a surface defect inspection apparatus of Working Example 5;

FIG. 3 is a photograph of a substrate surface state by a Nomarski microscope in Working Example 10.

FIG. 4 is a photograph of a substrate surface state by the surface defect inspection device of Working Example 10.

FIG. 5 is a photograph of a substrate surface state by a Nomarski microscope of Comparative Processing Example 1.

FIG. 6 is a photograph of a substrate surface state by a surface defect inspection device of Comparative Processing Example 1.

FIG. 7 is a photograph of a substrate surface state by a Nomarski microscope of Comparative Processing Example 2.

FIG. 8 is a photograph of a substrate surface state by a comparative processing example 2 surface defect inspection apparatus.

FIG. 9 is a diagram of a surface of a diamond pad on which tile-shaped protrusions are laid.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 5/73 G11B 5/73

Claims (10)

[Claims] 1. A method of processing a substrate material including a primary lap processing and a secondary processing, wherein the primary lap processing is performed by using diamond pellets in which diamond abrasive grains are fixed to a bond of resin, metal, vitrified or the like. The secondary processing is a step of precision grinding with a diamond pad after the primary lap processing, wherein the diamond pad has a large number of tile-shaped protrusions having flat tops. A method for processing a glass substrate material for an information storage medium or a glass ceramic substrate material, wherein the tile-shaped protrusions are formed by fixing diamond abrasive grains to a resin material. 2. In the primary lapping process, a resin,
The method for processing a glass substrate material for information storage media or a glass ceramic substrate material according to claim 1, wherein the particle size of the diamond abrasive grains fixed to the bond of metal, vitrified or the like is # 800 to # 1500. . 3. The glass substrate material for an information storage medium according to claim 1, wherein the Knoop hardness of the bond of the diamond pellet is in a range of 300 × 10 to 800 × 10 N / mm ^2. Or a method of processing a glass ceramic substrate material. 4. The glass for an information storage medium according to claim 1, wherein, in the secondary processing, a diamond pad has a diamond particle diameter in a range of 1 to 15 μm. Processing method of substrate material or glass ceramic substrate material. 5. The tile pad of the diamond pad has a Vickers hardness of 5 × 10 to 40 × 10 N / mm.
^The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to any one of claims 1 to 4, wherein the method is within the range of ( ² ). 6. A surface roughness R of a glass substrate material or a glass ceramic substrate material after secondary processing in the processing method.
a (arithmetic mean roughness) 50-800 °, Rp (maximum peak height) and Rv (maximum valley depth) 300-3000
The method for processing a glass substrate material for information storage media or a glass ceramic substrate material according to any one of claims 1 to 5, characterized by Å. 7. The method for processing a glass substrate material according to claim 7,
The glass substrate material to be processed is SiO ₂ —Al ₂ O ₃ —R ₂ O
The glass substrate material for an information storage medium according to any one of claims 1 to 6, wherein the glass substrate material is a chemically strengthened glass (where R is at least one selected from alkali metal elements). Processing method. 8. In the method for processing a glass ceramic substrate material, the glass ceramic substrate material to be processed is S
wherein the iO is ₂ -Al ₂ O ₃ -Li ₂ O system glass-ceramic or _{SiO 2 -Al 2 O 3 -MgO-} TiO 2 system glass ceramics, any one claim among claims 1 to 7 Processing method of glass ceramic substrate material for information storage medium. 9. The method for processing a glass substrate material or a glass ceramic substrate material, wherein a diamond particle diameter of a diamond pad in the secondary processing is in a range of 1 to 15 μm, and a processing slurry is 1.0 to 1.5 μm. 3 one of the abrasive ZrO ₂ or Al ₂ O ₃ range of
9. The composition according to claim 1, wherein the content is 20 wt%.
The method for processing a glass substrate material or a glass ceramic substrate material for an information storage medium according to any one of the above. 10. A glass substrate material or a glass ceramic substrate material for an information storage medium, which is processed by the method according to any one of claims 1 to 9.