JP3493777B2 - Manufacturing method of ferrite single crystal block - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ferrite single crystal block used as a material for a magnetic head or the like, and more particularly to a method for manufacturing a ferrite single crystal block having a plane orientation for VHS format.

[0002]

2. Description of the Related Art Generally, a ferrite single crystal block used as a material for a magnetic head or the like has a substantially cylindrical ferrite single crystal ingot 11 produced by growing it in a <110> crystal direction as shown in FIG. Dedicated stand 1
16 and the ferrite single crystal ingot 11 fixed to this dedicated stand 12 together with the dedicated stand 12 is indicated by an arrow D in FIG.
Direction, that is, from the side surface 11b of the ferrite single crystal ingot 11 to the lower surface 12a of the dedicated base 12 by slicing with a grinding blade (hereinafter, such a slicing method is referred to as a “transverse slicing method”). Called.).

By the way, a ferrite single crystal block conventionally used as a material for a magnetic head is (00
There has been a great demand for ferrite single crystal blocks having a plane orientation for β format, which are composed of 1) crystal faces and (110) crystal faces. Usually, such a ferrite single crystal block having a plane orientation for the β format is manufactured by slicing a ferrite single crystal ingot along a <1-10> crystal direction or a <001> crystal direction by a lateral slicing method. There is.

However, in recent years, with the remarkable spread of the VHS format, the ferrite single crystal block having the plane orientation for the β format is replaced with the (−111) crystal plane,
There is an increasing demand for a ferrite single crystal block having a plane orientation for the VHS format, which is composed of the (1-12) crystal face and the (110) crystal face.

Conventionally, such a ferrite single crystal block having a plane orientation for VHS format is also prepared by slicing a ferrite single crystal ingot by a lateral slicing method, similarly to a ferrite single crystal block having a plane orientation for β format. is doing. At this time, normally, (-11
1) The ferrite single crystal ingot is sliced along the <1-12> crystal direction so that the crystal plane becomes the main surface of the ferrite single crystal block, and a ferrite single crystal block having a plane orientation for the VHS format is produced.

By the way, the state of the ferrite single crystal ingot at the time of slicing differs greatly depending on the slicing direction of the ferrite single crystal ingot.

Specifically, for example, the state of the etch pits of the (110) crystal face 11a, which is the cross section of the ferrite single crystal ingot, is as shown in FIGS. 17 to 19 depending on the slicing direction. Here, FIG. 17 shows <1-1
0> shows a state when the ferrite single crystal ingot 11 is sliced along the crystal direction 11A, and FIG.
01> shows a state when the ferrite single crystal ingot 11 is sliced along the crystal direction 11B, and FIG.
1-12> shows the state when the ferrite single crystal ingot 11 is sliced along the crystal direction 11C.

That is, as shown in FIG. 17, <1-1
When slicing the ferrite single crystal ingot 11 along the 0> crystal direction 11A, the etch pits 11e of the (110) crystal face 11a are oriented in the vertical direction with respect to the slicing direction, and as shown in FIG. When the ferrite single crystal ingot 11 is sliced along the 001> crystal direction 11B, the etch pits 11e of the (110) crystal face 11a are oriented laterally with respect to the slicing direction, and as shown in FIG. 1-12> crystal direction 11C
When the ferrite single crystal ingot 11 is sliced along the
Is diagonal to the slicing direction.

Further, Table 1 shows the longitudinal elastic modulus of the ferrite single crystal block obtained by the four-point bending test, and the ferrite single crystal ingot was sliced along the <1-10> crystal direction to prepare the ferrite single crystal block. And when the ferrite single crystal ingot was sliced along the <001> crystal direction to produce a ferrite single crystal block, and when the ferrite single crystal ingot was sliced along the <1-12> crystal direction. The case where a crystal block is manufactured is shown.

[0010]

[Table 1]

As is apparent from FIGS. 17 to 19 and Table 1, the cubic ferrite single crystal is
While the (100) crystal plane is a cleavage plane, (1
10) The crystal plane is also a surface that is easily cracked. Therefore, it is understood that it is easy to slice the ferrite single crystal ingot along the <1-10> crystal direction or the <001> crystal direction.

[0012]

However, as shown in FIG.
As can be seen from Table 1 and Table 1, the ferrite single crystal ingot is <1 as in the case of producing a ferrite single crystal block having a plane orientation for the VHS format by the horizontal slicing method.
-12> When slicing along the crystal direction, the direction of the cleavage plane is oblique to the slice direction. Therefore, the grinding blade easily escapes along the cleavage plane in a direction other than the slice direction, for example, the <110> crystal direction.

Therefore, when a ferrite single crystal block having a plane orientation for the VHS format is produced, the lateral slicing method has poor machinability and it is difficult to cut out a flat block with high thickness accuracy. Moreover, since the grinding blade easily escapes in a direction other than the slicing direction along the cleavage plane during slicing, the grinding blade tends to warp in the lateral direction without going straight, and the crystal orientation of the obtained ferrite single crystal block tilts. I was afraid.

Further, in the case of the transverse slicing method, while slicing the ferrite single crystal ingot along the <1-12> crystal direction, the grinding blade is constantly subjected to a force transverse to the slicing direction. Since it works, the grinding blade is burdened, the grinding blade itself is distorted, and the life of the grinding blade is shortened.

Therefore, the present invention has been proposed in view of such a conventional situation, and has a (-111) crystal plane,
An object of the present invention is to provide a method for precisely cutting a ferrite single crystal block having a plane orientation for VHS format composed of (1-12) crystal face and (110) crystal face into a flat surface without burdening a grinding blade. And

[0016]

A method for manufacturing a ferrite single crystal block of the present invention completed to achieve the above object is a substantially cylindrical ferrite single crystal manufactured by growing in a <110> crystal direction. It is characterized in that the ingot is sliced from the (110) crystal plane, which is one end surface of the cylinder, along the <110> crystal direction toward the other end surface of the cylinder.

Here, the ferrite single crystal ingot is sliced, for example, so that the principal surface after slicing is the (-111) crystal plane.

However, the main surface after slicing is (-111)
When slicing to form a crystal plane, it is preferable to previously form an orientation flat surface serving as a mark of the (−111) crystal plane on the ferrite single crystal ingot.

The ferrite single crystal ingot is preferably sliced using an inner peripheral blade as a grinding blade.

The above-mentioned crystal plane indices (110), (-
It goes without saying that 111) and the crystallographic direction index <110> include indexes equivalent to the crystallographic plane index and the crystallographic direction index.

[0021]

In the present invention, the ferrite single crystal ingot is
Since the slice is performed along the 110> crystal direction, the direction of the cleavage plane and the slice direction do not become oblique. Therefore, it is possible to cut out a flat block having excellent machinability and high thickness accuracy. Moreover, since the grinding blade does not warp in the lateral direction during slicing, there is no fear that the crystal orientation of the obtained ferrite single crystal block will be tilted.

Further, in the present invention, since the direction of the cleavage plane and the slice direction are not inclined, no force is applied to the grinding blade in the lateral direction with respect to the slice direction. Therefore, the load on the grinding blade is reduced.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings. The present invention is of course not limited to the examples below. In the following examples, the crystal plane index (00
1), (110), (-111), (1-12), etc., and <110>, <1-10>, <
1-12> and the like are used. However, since the ferrite single crystal is a cubic crystal, it goes without saying that the effects of the present invention can be obtained even when the indices are equivalent to the crystal plane index and the crystal orientation index.

Example 1 First, a method for manufacturing a ferrite single crystal block having a plane orientation for a VHS format, to which the present invention is applied, will be described.

When the present invention is applied to manufacture a ferrite single crystal block having a plane orientation for VHS format,
First, a ferrite single crystal is prepared by the Bridgman method or the like.
110> Grow in the crystal direction to manufacture a substantially columnar ferrite single crystal ingot 1 as shown in FIG. 1 (ingot manufacturing step).

Next, as shown in FIG. 2, the lower surface 2a is a flat surface and the upper surface is a curved surface conforming to the side surface shape of the ferrite single crystal ingot 1. Ferrite single crystal ingot 1 on base 2
Is attached and fixed with an epoxy resin or the like (first fixing step). At this time, the ferrite single crystal ingot 1 is
The (-111) crystal plane and the lower surface 2a of the first dedicated base 2 are fixed to the first dedicated base 2 so that they are substantially parallel to each other.

Next, the first dedicated base 2 to which the ferrite single crystal ingot 1 is fixed is fixed to a gonio jig, and the crystal orientation of the ferrite single crystal ingot 1 is accurately measured by an optical image method using a laser. Determine (axis alignment process).

Next, as shown in FIG. 3, the unnecessary portions of the front and rear ends of the ferrite single crystal ingot 1 whose crystal orientation has been accurately determined are placed in parallel with the (110) crystal plane as the first portion.
The dedicated surface 2 is cut to form the reference surfaces 1a and 1b (reference surface forming step). At this time, if the ferrite single crystal ingot 1 is long, the ferrite single crystal ingot 1 is cut into a suitable length along with the first dedicated base 2 and divided.

Next, as shown in FIG. 4, the lower side of the ferrite single crystal ingot 1 whose crystal orientation is accurately determined, that is, the side in contact with the first dedicated base 2 is (-111).
The first dedicated table 2 is cut in parallel with the crystal plane to form the orientation flat surface 1c (orientation flat surface forming step).

Next, the first dedicated base 2 is removed from the ferrite single crystal ingot 1 on which the orientation flat surface 1c is formed,
As shown in FIG. 5, the ferrite single crystal ingot 1 having the reference planes 1a and 1b and the orientation flat surface 1c formed on the second dedicated base 3 made of ceramics having a substantially L-shaped cross section and excellent in machinability is attached to the orientation flat. The surface 1c and the one reference surface 1a are set upright in the longitudinal direction so as to be in contact with the second dedicated base 3 and fixed (second
Fixing process).

Next, as shown in FIG. 6, the ferrite single crystal ingot 1 is set together with the second dedicated base 3 in an inner peripheral blade slicing machine having an inner peripheral blade 4. At this time,
In the ferrite single crystal ingot 1, the main surface of the ferrite single crystal after slicing is the (−111) crystal plane,
That is, the inner peripheral blade 4 and the orientation flat surface 1c are made parallel to each other, and the slicing direction A by the inner peripheral blade 4 is set to the <110> crystal direction 1A of the ferrite single crystal, so that the inner peripheral blade slicing machine is provided. Set (slice preparation process).

By the way, the inner peripheral blade slicing machine is a slicing machine which uses, as a grinding blade, an inner peripheral blade having a blade provided on the inner periphery of a wheel, and a workpiece is directed from the inside of the inner peripheral blade to the outside thereof. The work is sliced by moving it. Such an inner peripheral blade slicing machine is easier to slice a thick workpiece as compared with a slicing machine using an outer peripheral blade provided with a blade on the outer periphery of a ring, and a relatively thin blade, The work piece can be sliced with good thickness accuracy.

Next, as shown in FIG. 7, an inner peripheral edge slicing machine is used to extend along the longitudinal direction of the ferrite single crystal ingot 1, that is, the reference plane 1 which is the (110) crystal plane.
The ferrite single crystal ingot 1 is sliced into a predetermined thickness along with the second dedicated base 3 along the <110> crystal direction 1A from b to prepare a ferrite single crystal slice 5 as shown in FIG. 8 ( Slicing process).

Next, the sliced surface of the ferrite single crystal slice 5 is polished with a lap to give a surface finish (lap step). Then, the crystal plane orientation of the ferrite single crystal slice 5 is inspected by an X-ray counter method or the like (face inspecting step).

Next, the ferrite single crystal slice 5 is cut into blocks of a predetermined size, and as shown in FIG.
The ferrite single crystal block 6 is produced (block processing step). Then, the physical properties, mechanical properties, dimensions, plane orientation, etc. of this ferrite single crystal block 6 are confirmed (shipment inspection step).

Through the above steps, a ferrite single crystal block having a plane orientation for the VHS format is produced.

Comparative Example 1 Next, a method of manufacturing a ferrite single crystal block having a plane orientation for the VHS format using the horizontal slicing method will be described.

Even when the ferrite single crystal block having the plane orientation for the VHS format is manufactured by the horizontal slicing method, the steps up to the ingot preparation step, the first fixing step, the axis alignment step and the reference plane forming step are performed in the same manner as in Example 1. In this way, a ferrite single crystal ingot having a reference plane is formed. However, when the ferrite single crystal ingot is fixed to the ceramic first dedicated table, the (1-12) crystal plane of the ferrite single crystal ingot and the lower surface of the first dedicated table are made parallel to each other.

Then, as shown in FIG. 10, the ferrite single crystal ingot on which the reference plane is formed is sliced by the lateral slicing method so as to have a plane orientation for the VHS format.

That is, as shown in FIG. 11, the ferrite single crystal ingot 1 is placed together with the first dedicated base 2 so that the main surface of the sliced ferrite single crystal is the (−111) crystal plane, that is, the inner circumference. The blade 4 and the (−111) crystal plane are made parallel to each other, and the direction B of slicing by the inner peripheral blade 4 is <1-12> crystal direction 1 of the ferrite single crystal.
Set to B, and set on the inner peripheral blade slicing machine (slice preparation step). Then, with the inner peripheral blade slicing machine, the ferrite single crystal ingot 1 is moved from the side surface of the ferrite single crystal ingot 1 along the <1-12> crystal direction 1B toward the lower surface 2a of the first dedicated base 2, Slice to a predetermined thickness with the first dedicated stand 2,
A ferrite single crystal slice is produced (slice processing step).

Thereafter, as in the first embodiment, the lapping step,
The surface inspection process, block processing process, and shipping inspection process are performed. Through the above steps, a ferrite single crystal block having a plane orientation for the VHS format is manufactured.

Comparative Example 2 Next, a method of manufacturing a ferrite single crystal block having a plane orientation for β format using the lateral slice method will be described.

Even when the ferrite single crystal block having the plane orientation for the β format is manufactured by the horizontal slicing method, the steps up to the ingot preparation step, the first fixing step, the axis-alignment step and the reference plane forming step are performed in the same manner as in Example 1. In this way, a ferrite single crystal ingot having a reference plane is formed. However,
When the ferrite single crystal ingot is fixed to the first ceramic table made of ceramics, the (110) crystal plane of the ferrite single crystal ingot and the lower surface of the first table are parallel to each other.

Then, as shown in FIG. 12, the ferrite single crystal ingot on which the reference plane is formed is sliced by the lateral slicing method so as to have a plane orientation for β format.

That is, a ferrite single crystal ingot 1
With the first dedicated table 2 such that the main surface of the ferrite single crystal after slicing is the (001) crystal plane, that is, the inner peripheral blade and the (001) crystal surface are parallel to each other, and The slicing direction by the blade is set to the <1-10> crystal direction of the ferrite single crystal and set in the inner blade slicing machine (slice preparation step). Then, the inner peripheral blade slicing machine was used to move the ferrite single crystal ingot 1 from the side surface of the ferrite single crystal ingot 1 along the <1-10> crystal direction toward the lower surface 2a of the first dedicated base 2 to the first side. The dedicated stand 2 of No. 1 is sliced to prepare a ferrite single crystal slice (slice processing step).

Thereafter, as in the first embodiment, the lapping step,
The surface inspection process, block processing process, and shipping inspection process are performed. Through the above steps, a ferrite single crystal block having a plane orientation for β format is manufactured.

Regarding Warp Amount and Life of Inner Circumferential Blade Next, regarding the above Example 1, Comparative Example 1 and Comparative Example 2, the warp amount of the inner peripheral blade when the ferrite single crystal ingot is sliced is measured. At the same time, the life of the inner peripheral blade was examined. The measurement was performed using an inner peripheral blade having an outer diameter of about 27 inches and a thickness of about 0.35 mm, and the rotation speed of the inner peripheral blade was about 1600 rotations / minute. The ferrite single crystal ingot to be sliced had a diameter of about 70 mm and a height of about 90 mm. Therefore, in Example 1, the cutting length, which is the length of the portion cut by the inner peripheral blade, is about 90 mm, and in Comparative Examples 1 and 2, the maximum cutting length is about 70 mm.

First, FIGS. 13 to 15 show the results of sensor measurement of the amount of warp of the inner peripheral blade when the ferrite single crystal ingot is sliced. Here, FIG. 13 shows the measurement results of Example 1, FIG. 14 shows the measurement results of Comparative Example 1, and FIG. 15 shows the measurement results of Comparative Example 2. 13 to 15, the vertical axis shows how far the inner peripheral blade has advanced with respect to the ferrite single crystal block, and the horizontal axis shows the amount of warp of the inner peripheral blade.

As is apparent from FIGS. 14 and 15, in the conventional horizontal slicing method, as in Comparative Example 2, β
When a ferrite single crystal block having a plane orientation for a format is produced, the inner peripheral blade has a small amount of warpage, but Comparative Example 1
As described above, when a ferrite single crystal block having a plane orientation for the VHS format is produced, the inner peripheral edge escapes in a direction other than the slicing direction, resulting in a large amount of warp of the inner peripheral edge. I understand.

On the other hand, as is clear from FIG. 13, in Example 1, even when the ferrite single crystal block having the plane orientation for the VHS format was produced, the inner peripheral edge escaped in a direction other than the slice direction. The inner peripheral blade has a very small amount of warp. Therefore, in Example 1, it can be understood that the ferrite single crystal block having the plane orientation for the VHS format can be accurately and flatly cut, and the crystal orientation of the ferrite single crystal block is not inclined.

Next, the results of examining the life of the inner peripheral blade are shown in Table 2.
Shown in. Here, the life of the inner peripheral blade is that the inner peripheral blade bursts or the inner peripheral blade warps greatly,
It is represented by the number of times (number of shots) of slicing the ferrite single crystal block, which was carried out until the slice became impossible.

[0052]

[Table 2]

As is clear from Table 2, in the transverse slicing method which is a conventional method, when the ferrite single crystal block having the plane orientation for β format is produced as in Comparative Example 2, the life of the inner peripheral blade is long. However, as in Comparative Example 1, VHS
When manufacturing a ferrite single crystal block with a plane orientation for format, the life of the inner peripheral blade will be significantly shortened. On the other hand, in Example 1, even if the ferrite single crystal block having the plane orientation for the VHS format was produced,
The inner blade has a long life, and the same level of life is obtained as when a ferrite single crystal block having a plane orientation for β format is manufactured by the transverse slicing method.

[0054]

As is apparent from the above description, in the present invention, the ferrite single crystal ingot is sliced along the <110> crystal direction, which is easy to slice, and the ferrite single crystal block having a plane orientation for the VHS format is sliced. Therefore, the ferrite single crystal block having the plane orientation for the VHS format can be produced with high accuracy and without the crystal orientation tilting.

Further, according to the present invention, since the burden on the grinding blade is reduced, the life of the grinding blade can be extended.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a ferrite single crystal ingot.

FIG. 2 is a perspective view showing an example of a state in which a ferrite single crystal ingot is fixed to a first dedicated base.

FIG. 3 is a perspective view showing an example of a ferrite single crystal ingot obtained by cutting a front end portion and a rear end portion.

FIG. 4 is a perspective view showing an example of a ferrite single crystal ingot on which an orientation flat surface is formed.

FIG. 5 is a perspective view showing an example of a state in which a ferrite single crystal ingot is fixed to a second dedicated base.

FIG. 6 is a front view schematically showing a state in which a ferrite single crystal ingot is set in an inner peripheral blade slicing machine.

FIG. 7 is a perspective view showing an example of a sliced ferrite single crystal ingot.

FIG. 8 is a perspective view showing an example of a ferrite single crystal slice.

FIG. 9 is a perspective view showing an example of a ferrite single crystal block.

FIG. 10 is a perspective view showing an example of a state where a ferrite single crystal ingot is sliced by a horizontal slicing method.

FIG. 11 is a front view schematically showing a state in which a ferrite single crystal ingot is set on an inner peripheral blade slicing machine in the horizontal slicing method.

FIG. 12 is a perspective view showing another example of a state where a ferrite single crystal ingot is sliced by the horizontal slicing method.

FIG. 13 is a diagram showing a measurement result of a warp amount of the inner peripheral blade in the first embodiment.

FIG. 14 is a diagram showing a measurement result of a warp amount of an inner peripheral blade in Comparative Example 1.

FIG. 15 is a diagram showing a measurement result of a warp amount of an inner peripheral blade in Comparative Example 2.

FIG. 16 is a perspective view schematically showing how a ferrite single crystal block is sliced by a horizontal slicing method.

FIG. 17 is a cross-sectional view of a ferrite single crystal ingot that schematically shows a state of etch pits when the ferrite single crystal ingot is sliced along the <1-10> crystal direction.

FIG. 18 is a cross-sectional view of a ferrite single crystal ingot schematically showing a state of etch pits when the ferrite single crystal ingot is sliced along the <001> crystal direction.

FIG. 19 is a cross-sectional view of a ferrite single crystal ingot that schematically shows a state of an etch pit when the ferrite single crystal ingot is sliced along the <1-12> crystal direction.

[Explanation of symbols]

1 Ferrite single crystal ingot 2 first exclusive stand 3 second exclusive stand 4 inner blade 5 Ferrite single crystal slice 6 Ferrite single crystal block

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B28D 5/02 C30B 29/22 G11B 5/133 H01L 21/304

Claims (4)

(57) [Claims] 1. A substantially cylindrical ferrite single crystal ingot produced by growing in a <110> crystal direction is formed into a cylindrical shape along a <110> crystal direction from a (110) crystal plane, which is one end surface of the cylinder. A method for manufacturing a ferrite single crystal block, which comprises slicing toward the other end surface. 2. The method for producing a ferrite single crystal block according to claim 1, wherein the ferrite single crystal ingot is sliced so that the main surface after slicing is a (−111) crystal plane. 3. The ferrite single crystal ingot,
The method for producing a ferrite single crystal block according to claim 2, wherein an orientation flat surface serving as a mark of the (-111) crystal surface is formed in advance. 4. The ferrite single crystal ingot is sliced using an inner peripheral blade.
Alternatively, the manufacturing method of the ferrite single crystal block according to the above item 3.