JPH09131654A - Recording medium substrate processing method and processing grindstone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the service life of a diamond grinding wheel to be used by performing the grinding using a plurality of diamond grinding faces having the particle size distribution of different mean grain size to suppress occurrence a of chipping during the grinding in a working method of a substrate for a recording medium. SOLUTION: Grinding is performed using a plurality of diamond grinding faces having the particle size distribution of different mean grain size in a working method of a substrate 1 for a recording medium in which chamfered parts 2, 3 are ground on the inner and outer circumferential surfaces of a substrate 1A. In grinding the chamfered parts 2, 3 on the end face of the inner and outer circumference of the substrate body 1A, most of the whole margin is ground by a diamond grinding face with large mean grain size of long service life, and the residual margin is finely ground by the small amount by a diamond grinding face of small mean grain size. The end face of the substrate body 1A is difficult to generate chipping during the grinding, the film such as the texture layer to be formed on the substrate body is excellently adhered in the film making process after the chamfering, and the film peeling is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing a substrate for a recording medium by various recording methods (magnetic, magneto-optical, optical) and a processing grindstone.

[0002]

2. Description of the Related Art A substrate for a recording medium typified by a hard disk (HD) substrate is a lapping process for roughly polishing the surface of a substrate body, a chamfering process for chamfering the inner and outer peripheral end faces to be chamfered, and a final polishing for the surface. It is manufactured through a polishing process. Then, this substrate further has a texture step of forming a texture layer on the surface of the substrate body to appropriately roughen the surface, an underlayer forming step of forming an underlayer on the surface, and a magnetic layer formed on the surface. Magnetic layer forming step, a protective layer forming step of forming a protective layer on the magnetic layer,
A product is formed by forming a film on the surface of the substrate body in a lubricating layer forming step of forming a lubricating layer on the protective layer, and then performing a burnishing step of removing abnormal protrusions on the film surface.

In the prior art, a diamond grindstone is used in the chamfering process described above.

[0004]

According to the results of experiments and research conducted by the present inventor, when the average abrasive grain size of the diamond grindstone used in the chamfering process is large (coarse), a chip during chamfering occurs on the end face of the substrate body. It is easy to do so, and adhesion of a film such as a texture layer formed thereon in the film forming step after chamfering is poor, resulting in inconvenience such as film peeling.

Therefore, it is conceivable to use a diamond grindstone having a small (fine) average abrasive grain size. In this case, the diamond grinding stone having a small average abrasive grain size is used to grind the entire machining allowance of the chamfered portion of the substrate body. As a result, the life of the grindstone is inevitably short.

An object of the present invention is to suppress the occurrence of a chip during processing on the end face of the substrate body when grinding the chamfered portion on the end face of the substrate body, and to extend the life of the diamond grindstone to be used. is there.

[0007]

According to a first aspect of the present invention, there is provided a method for processing a substrate for a recording medium, wherein a chamfered portion is ground on the inner and outer peripheral end faces of a substrate body, and the grain sizes are different from each other in average abrasive grain size. The grinding is performed using a grindstone having a plurality of diamond grinding surfaces having a distribution.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the grinding process by the diamond abrasive surface having the large average abrasive grain size to the grinding by the diamond abrasive surface having the small average abrasive grain size is performed. The processing is switched stepwise and continuously.

According to a third aspect of the present invention, in a grinding wheel for a recording medium substrate used for grinding a chamfered portion on the inner and outer peripheral end faces of a substrate body, the grain size distributions of different average grain sizes are different from each other. The plurality of diamond polishing surfaces that the device has are provided on a single washer.

According to a fourth aspect of the present invention, in addition to the third aspect of the present invention, the grindstone is a disk or a column.

According to a fifth aspect of the present invention, in addition to the third or fourth aspect of the present invention, a plurality of sets of diamond grindstone groups are provided on the washer, and each of the diamond grindstone groups has an average grind. A plurality of diamond abrasive surfaces having the same particle size distribution of particle diameters are provided in parallel, and different diamond abrasive surface groups each have different average abrasive particle diameters of the particle size distributions of the diamond abrasive surfaces belonging to them. is there.

The present invention according to claim 6 is based on claims 3 to 5.
In any one of the present inventions, the average abrasive grain diameter of the diamond abrasive surface having a smaller average abrasive grain diameter is 30 μm or less.

The present invention according to claim 7 provides the invention according to claims 3 to 5.
In any one of the present inventions, the average abrasive grain size of the diamond abrasive surface having a smaller average abrasive grain size is 20 μm or less.

According to the present invention described in claims 1 and 2, the following operational effects are obtained. When the chamfered portion is ground on the inner and outer peripheral end faces of the substrate body, processing with a diamond abrasive surface having a large average abrasive grain diameter and processing with a diamond abrasive surface having a small average abrasive grain diameter are sequentially performed. Therefore, most of the total chamfering allowance of the chamfered part of the substrate body is ground with a long-life diamond abrasive surface with a large average abrasive grain size, and then the remaining allowance of the chamfering part is removed with a diamond abrasive surface with a small average abrasive grain size. Fine grinding (small roughness) is required. As a result, both the life of the diamond grinding surface having a large average grinding particle diameter and the life of the diamond grinding surface having a small mean grinding particle diameter can be extended, and as a result, the life of the diamond grinding stone can be extended.

As a result of the chamfered portion of the substrate body being finely ground (small roughness) by the diamond abrasive surface having a small average grain size, chipping during grinding is unlikely to occur at the end face of the substrate body.
As a result, the film such as the texture layer formed thereon in the film-forming step after the chamfering process adheres well, and the film does not peel off.

According to the present invention described in claim 3, the following operational effects are obtained. A single washer constituting a diamond grindstone is provided with a plurality of diamond grinding surfaces having particle size distributions having different average grinding particle sizes. Therefore, once the substrate is chucked in the chamfer processing apparatus, the chamfered portion of the substrate body can be ground stepwise and continuously with the plurality of diamond abrasive surfaces having different average abrasive grain diameters, and the productivity can be improved.

According to the present invention described in claims 4 and 5, the following operational effects are obtained. A plurality of sets of diamond grinding surface groups were provided on a single washer constituting the diamond grinding stone. Therefore, for the substrate body,
Grinding with one diamond grinding surface in the diamond grinding surface group having a large average grinding particle diameter and grinding processing using one diamond grinding surface in the diamond grinding surface group having a small grinding particle diameter Become. Then, when the above-mentioned one diamond grinding surface in the diamond grinding surface group having a large average grinding grain size reaches the end of its life, another diamond grinding stone in the diamond grinding surface group is used. When the above-mentioned one diamond abrasive surface in the diamond abrasive surface group having a small average abrasive grain size reaches the end of its life, another diamond abrasive surface in the diamond abrasive surface group is used. Therefore, in addition to the above effects, it is possible to reduce the frequency of exchanging the grindstone for attaching / detaching the grindstone to / from the chamfer processing device, and to improve the productivity.

According to the present invention described in claim 6, the following operational effects are obtained. The average grain size of the diamond grinding surface with a smaller average grain size
By making it 30 μm or less, the roughness imparted to the chamfered part of the substrate body is made finer and the number of chippings that may occur during grinding of the end face of the substrate body is reduced (eg 1 or less per substrate )it can.

The present invention according to claim 7 has the following operational effects. The average grain size of the diamond grinding surface with a smaller average grain size
By setting the thickness to 20 μm or less, the roughness imparted to the chamfered portion of the substrate body is made finer, and the number of chippings that may occur during grinding of the end face of the substrate body is further reduced (for example, 1 per substrate). Less than)

[0020]

1 is a schematic diagram showing a substrate, FIG. 2 is a schematic diagram showing a film structure of the substrate, FIG. 3 is a schematic diagram showing a chamfer processing apparatus, and FIG. 4 is a diamond grinding stone for peripheral chamfering. Fig. 5 is a schematic diagram showing an inner peripheral chamfering diamond grindstone, and Fig. 6 is a diagram showing the relationship between the average abrasive grain size of the diamond grindstone and the number of occurrences of chipping.

Glass-like carbon substrate for magnetic disk (G
The C substrate 1 has the substrate body 1A processed by the following (1) to (3). (1) Lapping step The surface of the substrate body 1A is roughly polished with loose abrasive grains.

(2) Chamfer processing step The inner and outer peripheral end faces of the substrate body 1A are ground and chamfered. FIG.
2 is an outer peripheral chamfered portion, and 3 is an inner peripheral chamfered portion.

(3) Polishing Step The surface of the substrate body 1A is finish-polished. Where
The chamfer processing device used in the chamfer processing step (2) will be described (FIG. 3).

The chamfer processing apparatus 10 includes a chuck stage 11, a clamp 12, diamond grindstones 13 and 14.
Is configured.

The chuck stage 11 applies a vacuum pressure to the concentric convex portion 11A that supports the substrate body 1A, a vacuum suction groove 11B that vacuum-sucks the substrate body 1A around the convex portion 11A, and a vacuum suction groove 11B. A vacuum supply path 11C is provided. As a result, the chuck stage 11 moves to the substrate body 1
A can be vacuum-adsorbed.

The clamp 12 is a high-pressure water jet port 12A for applying high-pressure water to the substrate body 1A on the chuck stage 11.
The substrate body 1A can be pressed and held on the chuck stage 11.

The diamond grindstone 13 can chamfer the outer peripheral end surface of the substrate body 1A, and the diamond grindstone 14 can chamfer the inner peripheral end surface of the substrate body 1A.

However, in this embodiment, the diamond grindstones 13 and 14 are composed of the following (a) to (c) (FIG. 4). (a) The outer peripheral chamfering diamond grindstone 13 is provided in a plurality of sets (2 in this embodiment) on a single disk or columnar washer 30.
It has a group of diamond grindstones 31, 32. The diamond grindstone group 31 includes a plurality of diamond grinding surfaces 31 having a large particle size distribution (for example, No. 325) with a large average grinding particle size.
A, 31B, 31C, ... Are vertically adjacently arranged in parallel. The diamond grinding surface group 32 is the diamond grinding surface group 3
A plurality of diamond abrasive surfaces 32A provided under 1 and having a small average abrasive particle size distribution (for example, No. 500),
32B, 32C ... Are provided in parallel vertically adjacent to each other.

(B) The inner peripheral chamfering diamond grindstone 14 is
A single disk or column-shaped washer 40 has a plurality of sets (two sets in this embodiment) of diamond abrasive surface groups 41 and 42. The diamond abrasive surface group 41 includes a plurality of diamond abrasive surfaces 41A, 41B, 41C, ... Which have a large average particle size distribution (for example, No. 325) and are vertically adjacent to each other in parallel. The diamond abrasive surface group 42 is provided below the diamond abrasive surface group 41, and has a plurality of diamond abrasive surfaces 42A, 42B, 42C, ... Which have a small average particle size distribution (for example, No. 500) and are vertically adjacent to each other. Prepare in parallel.

(C) Diamond grinding surface groups 31, 32, 41 provided on the respective diamond grinding stones 13, 14;
Between the average abrasive grain size of No. 42 and the number N (pieces) of chipping generated on the end surface of one GC substrate by chamfering,
There is a relationship. According to this, when the average abrasive grain size is 30 μm, the number of occurrences of chipping is one.

Therefore, in the diamond grindstones 13 and 14, the average abrasive grain size of the diamond abrasive surface groups 31, 32, 41 and 42 is preferably 30 μm or less (the number of chipping occurrences is 1 or less), and more preferably. 20 μm or less (less than 1 chipping occurred)
And

In this embodiment, the diamond grindstones 13 and 14 are used according to the following (1) to (4). (1) The substrate main body 1 is formed by one diamond grinding surface 31A, 41A of the diamond grinding surface group 31, 41 having a large particle size distribution with a large average grinding particle size of the diamond grinding wheels 13, 14.
Chamfer grinding is performed on A.

(2) Diamond abrasive surface group 3 having a small particle size distribution of the average abrasive particle size of the diamond grindstones 13 and 14
One diamond grinding surface 32A, 42A of 2, 42
Then, the substrate body 1A is chamfered and ground. The above (1) and (2) are repeated for each substrate body 1A.

(3) When one of the diamond abrasive surfaces 31A, 41A in the diamond abrasive surface groups 31, 41 having a large average abrasive particle size distribution reaches the end of its life, the diamond abrasive surface groups 31, 41 The above (1) is performed on the other one of the diamond grinding surfaces 31B and 41B.

(4) When the above-mentioned one diamond abrasive surface 32A, 42A of the diamond abrasive surface groups 32, 42 having a small average particle size distribution reaches the end of its life, the diamond abrasive surface groups 32, 42 The above (2) is performed on the other one of the diamond grinding surfaces 32B and 42B.

In the GC substrate 1, the above-mentioned substrate body 1A is subjected to, for example, the following film formation, and finally the following burnishing process is performed to obtain a product (FIG. 2). Ti layer forming step The Ti layer 1B is formed on the substrate body 1A.

Texture step An Al-Si uneven layer 1C (texture layer) is formed on the Ti layer 1B, and the surface is appropriately roughened.

Carbon Layer Forming Step A carbon layer 1D is formed on the texture layer 1C.

Underlayer forming step: Ti underlayer 1E and Cr underlayer 1F are formed on the carbon layer 1D.
Are formed in order.

Magnetic Layer Forming Step A magnetic layer (recording layer) 1G is formed on the Cr underlayer 1F.

Protective Layer Forming Step A carbon protective layer 1H is formed on the magnetic layer 1G.

Lubricating Layer Forming Step A lubricating layer 1I is formed on the protective layer 1H.

Burnishing step Abnormal protrusions on the surface are removed.

The operation and effect of this embodiment will be described below. When grinding the chamfered portions 2 and 3 on the inner and outer peripheral end surfaces of the substrate body 1A, a diamond abrasive surface 31 having a large average abrasive grain size
Processing by A, 41A, ..., Processing by diamond abrasive surfaces 32A, 42A, ... Therefore, most of the chamfered portions 2, 3 of the substrate body 1A are ground by the diamond abrasive surfaces 31A, 41A, ... Having a long life and a large average abrasive grain diameter, and then the diamond abrasive surface having a small average abrasive grain diameter. By 32A, 42A ..., The remaining machining allowance of the chamfered portions 2 and 3 is finely ground (small roughness) in a minute amount. As a result, the life of the diamond grinding surfaces 31A, 41A ... With a large average grinding particle diameter and the life of the diamond grinding surfaces 32A, 42A .. It can be extended.

The chamfered portions 2 and 3 of the substrate body 1A are finely (smallly) ground by the diamond abrasive surfaces 32A, 42A ... Having a small average grain size, and as a result, the end faces of the substrate body 1A are being ground. The chipping is unlikely to occur, and the film such as the texture layer formed thereon in the film-forming step after the chamfering process adheres well, and the film does not peel off.

A plurality of diamond grinding surfaces 31A, 32A, ... 41 having a particle size distribution with different average grinding particle diameters on a single washer 30 constituting the diamond grinding stones 13, 14.
A, 42A ... Are provided. Therefore, once the substrate 1 is chucked in the chamfering machine 10, the plurality of diamond abrasive surfaces 31A, 32 having different average abrasive grain diameters are used as they are.
, 41A, 42A ..., the chamfered portion 2 of the substrate body 1A,
3 can be ground stepwise and continuously, and productivity can be improved.

A plurality of sets of diamond grinding surface groups 3 are provided on the single washers 30 and 40 which form the diamond grinding stones 13 and 14, respectively.
1, 32, 41, 42 are provided. Therefore, the substrate body 1A
In contrast, a diamond abrasive surface group 31 having a large average abrasive grain size,
Grinding with one diamond abrasive surface 31A, 41A of 41 and one diamond abrasive surface 32A, 42 of the diamond abrasive surface group 32, 42 having a small average abrasive grain size
The grinding process by A is sequentially performed. And
When the one diamond abrasive surface 31A, 41A in the diamond abrasive surface group 31, 41 having a large average abrasive grain size reaches the end of its life, another diamond abrasive surface 31B in the diamond abrasive surface group 31, 41 , 41B are used. In addition, diamond abrasive surface groups 32, 42 having a small average abrasive grain size
When the above-mentioned one diamond grinding surface 32A, 42A of the above has reached the end of its life, the other one diamond grinding surface 32B, 42B of the diamond grinding surface group 32, 42 is used.
Therefore, in addition to the above effects, the frequency of exchanging the grindstones for attaching / detaching the grindstones 13 and 14 to / from the chamfer processing apparatus 10 can be reduced, and the productivity can be improved.

Diamond grinding surface 3 having a smaller average grinding grain size
By setting the average abrasive grain diameter of 2A, 42A ... to 30 μm or less, the roughness imparted to the chamfered portions 2 and 3 of the substrate body 1A is made finer, and there is a possibility that the edge face of the substrate body 1A may be generated during grinding. It is possible to reduce the number of occurrences of chipping (for example, 1 or less per substrate).

Diamond abrasive surface 3 having a small average abrasive grain size
By setting the average abrasive grain diameter of 2A, 42A ... to 20 μm or less, the roughness imparted to the chamfered portions 2 and 3 of the substrate body 1A can be made finer, and can occur on the end face of the substrate body 1A during grinding. It is possible to further reduce the number of occurrence of defective chips (for example, less than 1 per substrate).

In the practice of the present invention, it is possible to use a grindstone provided with three or more diamond abrasive surfaces (or diamond abrasive surface groups) having particle size distributions having different average abrasive particle sizes.

Further, the present invention shows a remarkable effect in a substrate made of a brittle material such as the GC substrate 1 and the glass substrate.

[0052]

[Example] A chamfer processing device 1 for a substrate body of a GC substrate
No. 0 outer peripheral chamfering diamond grindstone 13 and inner peripheral chamfering diamond grindstone 14
The lifespan of 3, 14 was investigated. Board size is 25 inches, 25
mil (outer diameter 65 mm, inner diameter 20 mm, plate thickness 0.635 mm).

The diamond whetstones 13 and 14 are provided with a diamond grinding surface having a large average particle size distribution (No. 325) and a diamond grinding surface having a small average particle size distribution (No. 500). , If the grinding process with the diamond grinding surface with a large average particle size is sequentially switched to the grinding process with a diamond grinding surface with a small average particle size, the life of the diamond wheels 13 and 14 is [500 substrates / It was a single grindstone]. On the other hand, the diamond grindstones 13 and 14 have a small average particle size distribution (500
In the conventional example including only the diamond grinding surface having the No.), the life of the diamond grinding wheels 13 and 14 was [200 substrates / single grinding wheel].

Further, in the practice of the present invention, the substrate main body is (1) lapping step, (2) fixed abrasive grain grinding step, (3)
It may be processed in a chamfer processing step or (4) finishing polishing step (optional).

[0055]

As described above, according to the present invention, when the chamfered portion is ground on the end face of the substrate body, it is possible to suppress the occurrence of chipping on the end face of the substrate body during processing and the life of the diamond grindstone to be used. Can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a substrate.

FIG. 2 is a schematic diagram showing a film configuration of a substrate.

FIG. 3 is a schematic diagram showing a chamfer processing device.

FIG. 4 is a schematic diagram showing an outer peripheral chamfering diamond grindstone.

FIG. 5 is a schematic diagram showing an inner peripheral chamfering diamond grindstone.

FIG. 6 is a diagram showing the relationship between the average grain size of a diamond grindstone and the number of occurrences of chipping.

[Explanation of symbols]

1 Substrate 1A Substrate body 2, 3 Chamfered portion 13, 14 Diamond grindstone 30, 40 Washer 31, 32, 41, 42 Diamond grindstone group 31A, 31B, 31C Diamond grinded surface (large average grain size) 32A, 32B, 32C Diamond Abrasive Surface (Small Average Abrasive Grain Size) 41A, 41B, 41C Diamond Abrasive Surface (Large Average Abrasive Grain Size) 42A, 42B, 42C Diamond Abrasive Surface (Small Average Abrasive Grain Size)

Claims (7)

[Claims] 1. A method of processing a substrate for a recording medium, which grinds chamfered portions on the inner and outer peripheral end surfaces of a substrate body, wherein a grindstone provided with a plurality of diamond grinding surfaces having grain size distributions having different average grain sizes. A method of processing a substrate for a recording medium, which comprises performing a grinding process using the same. 2. The recording medium according to claim 1, wherein the grinding process by the diamond grinding surface having the large average abrasive grain size is switched stepwise and continuously from the grinding process by the diamond grinding surface having the small average abrasive grain size. Substrate processing method. 3. A processing grindstone for a recording medium substrate used for grinding a chamfered portion on the inner and outer peripheral end faces of a substrate body, wherein a plurality of diamond abrasive surfaces having a particle size distribution with different average abrasive particle sizes from each other are used. A processing grindstone for a substrate for a recording medium, which is provided on one washer. 4. The processing grindstone for a substrate for a recording medium according to claim 3, wherein the grindstone is a disk or a column. 5. A plurality of sets of diamond grindstones are provided on the washer, and each diamond grindstone group is provided with a plurality of diamond grinding surfaces in parallel having the same particle size distribution of the average grind size in parallel. The processing grindstone for a substrate for a recording medium according to claim 3 or 4, wherein each of the abrasive surface groups has a different abrasive particle size distribution of the diamond abrasive surfaces belonging to them. 6. The working grindstone for a recording medium substrate according to claim 3, wherein the average abrasive grain diameter of the diamond abrasive surface having a smaller average abrasive grain diameter is 30 μm or less. 7. The processing grindstone for a substrate for a recording medium according to claim 3, wherein the average abrasive grain diameter of the diamond abrasive surface having a smaller average abrasive grain diameter is 20 μm or less.