JPH0652520A - Method and device for working thin film magnetic head - Google Patents

Abstract

PURPOSE:To provide a method for highly accurately working a thin film magnetic head with a less manhour and a device used for the method. CONSTITUTION:Before starting the cutting process of the substrate 2 of a thin film magnetic head element, the grinding process of a reference surface 5 is performed. In addition, both the polishing and cutting processes are simultaneously performed. In order to perform the processes simultaneously, a grinding wheel 9 and abrasive rutting wheel 1 are put on the same spindle shaft and the diameter of the wheel 9 is made larger than that of the wheel 1 so that the grinding process can precede the cutting process. Therefore, the arranging linearity of the element can be made parallel with the reference surface 5 of a block 4. In addition, the complicated reference surface grinding process which has been required by the conventional method becomes unnecessary and, since the block 4 on which elements are linearly arranged can be obtained, accurate and precise working can be performed thereafter. In addition, since the grinding and cutting processes are performed simultaneously, the manhour can be reduced while the above-mentioned effects are obtained.

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 thin film magnetic head with high accuracy and a processing apparatus used in the method.

[0002]

2. Description of the Related Art A thin film magnetic head, especially a video head, is small in size, but it needs a narrow gap width, a shallow gap, and a high speed rotation in order to record and reproduce a wide band video signal. Precise processing technology and strict process control are required. Considering the conventional manufacturing process,
There are material removal from the material, cutting into chips, flatness of the surface of the head facing the recording medium magnetic film, high-precision finishing of surface roughness, lapping, etc. In order to perform these processing accurately, That is, no deformation occurs in the cutting process.

A conventional technique will be described below with reference to FIGS. 4 and 5. FIG. 4 is an explanatory view of a main flow of a conventional method of processing a thin film magnetic head. FIG. 5 is a structural diagram of the thin film magnetic head. In FIG. 4, a thin film magnetic head processing step is an element forming step [R] for forming a magnetic head element on a substrate, a substrate cutting step [s] for cutting the substrate into blocks, and a jig for cutting the cut blocks for grinding. Jig adhering step [t], a reference surface grinding step [u] for grinding a cut surface of a block adhered to the jig, a peeling step [v] for peeling the ground block from the jig, and a peeling step. A jig adhering step [w] for adhering the ground surface of the block to the jig, a forming grinding step [x] for adhering the slider rail of the thin film magnetic head to the block adhered to the jig, adhering to the jig And a so-called air bearing surface polishing step [y] for forming the air bearing surface, and a cutting step [z] for individually separating the magnetic head element from the block. In FIG. 4, 1 is a cutting grindstone, 2 is a substrate on which a large number of magnetic head elements are formed, 3 is a magnetic head element formed on the substrate 2, and 4 is a block obtained by cutting the substrate 2 with the cutting grindstone 1. Reference numeral 5 is a reference surface, 6a and 6b are jigs, 7 is a varnish, and 9 is a polishing grindstone. Further, in FIG. 5, reference numeral 18 is a slider rail of the thin film magnetic head.

In the substrate cutting step [s] and the reference surface grinding step [u] among the processing steps of the thin film magnetic head, the magnetic head element manufactured in the element forming step [R] for cost reduction. It is common to process the substrate 2 in which a large number of layers are formed. Therefore, conventionally, in the substrate cutting step [s], first, the substrate 2 on which a large number of magnetic head elements 3 are formed is cut into blocks 4 by a cutting grindstone 1. The cutting direction is parallel to the arrangement of the magnetic head elements 3. At this time,
As shown in [s], the cutting surface waviness a occurs due to the bending of the cutting grindstone 1. Further, since the thickness of the cut block 4 is very thin, 1 mm or less, the internal stress generated in the work strain layer on the cut surface becomes unbalanced on both sides of the block 4, and new deformation b occurs. As a result, FIG.
As shown in [s'], the cutting causes a warp equal to (a + b) on the end surface of the block 4, and the linearity of the magnetic head elements 3 arranged on the end surface of the block 4 changes.

In the jig adhering step [t], as shown in FIG.
As shown in [u], cut the block 4 into a varnish 7
To the jig 6a. Next, in the reference surface grinding step [u], the surface of the cut block 4 on the side opposite to the bonding surface to the jig 6a is ground by a grinding wheel 9 into a smooth surface [hereinafter referred to as a reference surface]. . By such processing, when the blocks 4 are bonded to the jig 6b, the magnetic head elements 3 are bonded so as to be line-symmetric with respect to a line perpendicular to the bonding surface of the jig 6b. It will be easier. In this way, the slider of the thin film magnetic head H is
In the forming and grinding step [x] for forming the rails 18 and the air bearing surface polishing step [y] for the thin film magnetic head, uniform processing is performed to improve the yield. However, when the substrate 2 is cut, the strain generated in the block 4 and the block 4
Since the reference surface grinding is performed in a state in which there is a deformation amount of the head element array due to the strain generated when the is bonded to the jig 6, the reference surface 5 and the array of the magnetic head elements 3 are not parallel.
In the block 4 in which such a deformation amount of the head element array exists, the magnetic head element 3 is accurately and accurately
It is not possible to perform uniform precision processing. This will be described in the polishing of the surface of the head element facing the magnetic film of the recording medium, that is, the air bearing surface.

Prior to the air bearing surface polishing step [y], the block 4 is peeled from the jig 6a in the peeling step [v], and the reference surface 5 is fixed to the jig 6b again in the jig adhering step [w].
Glue to. In the state of the magnetic head elements 3 after adhesion, the amount of change in the arrangement of the magnetic head elements 3 (hereinafter referred to as the amount of deformation of the head elements array) is eliminated because the cutting surface waviness a at the time of cutting the substrate is removed by the deformation caused by adhesion. , (B-
a) will remain. This means that even in a magnetic head called a floating head, which is used while floating, many magnetic head elements formed in the block 4 are processed at the same time in the air bearing surface polishing step [y]. It is not possible to perform uniform precision machining on each element in the state where the amount of deformation of the array exists. For this reason, even if the thin film magnetic head is obtained by the individual head cutting step [z], it is impossible to satisfy the specifications. Further, as is apparent from the flow chart explanatory view of FIG. 4, a jig adhering step [t] for adhering a block cut for grinding to a jig, a block having a ground reference surface is ground from the jig. There were two jig bonding steps such as a peeling step [v] for peeling and a jig bonding step [w] for bonding the reference surface of the peeled block to a jig.

[0007]

In the above-described conventional method for processing a thin film magnetic head, it is not possible to manufacture a block in which the head element array is not deformed. Therefore, uniform precision processing can be performed on each element. Had the problem of not having.
Further, the fact that uniform precision processing cannot be performed on each element causes the following problems. This causes not only variations in the air bearing surface of the magnetic head, but also poor mechanical accuracy of the head gap shape, variations in the head gap depth, and the like. Generally, the recording density of the magnetic recording medium is better as the magnetic flux in the gap is larger,
The magnetic flux in this gap is closely related to the gap between the magnetic head and the magnetic film surface of the recording medium and the mechanical accuracy of the gap shape of the head. Also, head reproduction is better as the reproduction magnetic flux is larger, and this reproduction magnetic flux is closely related to the depth of the head gap.

FIG. 5 shows an example of a structural diagram of the thin film magnetic head H. The magnetic flux generated from the gap G is distributed in a mountain shape, and the closer to the gap G, the higher the magnetic flux density and the spread of the magnetic flux. Becomes smaller. That is, the recording density is improved by reducing the gap between the magnetic film surface of the recording medium of the magnetic disk device and the gap of the magnetic head. In a magnetic disk device, especially for a hard disk, a magnetic head has a levitation force and a head generated when an air flow is compressed by rotation of a magnetic disk in order to avoid damage due to contact with a magnetic film surface of a recording medium. It is used by floating it in balance with the force of the spring that presses against the disc. Due to the higher recording density, the distance between the magnetic film surface of the recording medium and the gap between the magnetic heads (the flying height of the magnetic head) should be as small as possible. A certain floating distance is required to avoid damage. Considering both of these, the actual spacing is 1 μm or less. Therefore, in processing the thin film magnetic head,
Precise machining of the air bearing surface is very important.

Further, in order to obtain the mechanical accuracy of the gap shape of the head described above, it is necessary to perform accurate precision processing. Further, when considering reproduction from the recording medium by the magnetic head, in order to increase the magnetic flux passing through the reproduction coil,
It is necessary to reduce the gap depth Gd and increase the magnetic resistance of the gap from the relative magnitude relationship between the magnetic resistance of the magnetic flux gap and the magnetic resistance of the reproducing coil. However, even if the gap depth Gd is made shallow, the magnetic flux is disturbed when mechanical processing is defective, and the magnetic resistance of the gap is adversely affected.
Furthermore, the double jig bonding complicates the process and increases the cost.

The present invention has been made in order to solve the above-mentioned problems of the prior art. A flat air bearing surface is formed by forming a block capable of reducing the deformation of the head element array and performing accurate precision machining. It is a primary object of the present invention to provide a thin film magnetic head having a mechanically accurate gap shape and a shallow gap depth, simplify the processing process, and provide a processing method with reduced cost. is there.

A second object of the present invention is to achieve the first object of the present invention, and simultaneously perform a cutting step and a grinding step to further reduce the number of steps, and further, an excellent method for processing a thin film magnetic head. To provide.

Further, a third object of the present invention is to provide a working method which comprises a grinding wheel and a cutting wheel and which shortens the number of steps for simultaneously carrying out the grinding step and the cutting step which is the second object of the present invention. Another object is to provide a thin-film magnetic head processing apparatus.

[0013]

In order to achieve the above first object, the structure of the first invention relating to a method of processing a thin film magnetic head is such that in the method of processing a thin film magnetic head, an element of the thin film magnetic head is A reference surface grinding step of grinding end surfaces of a large number of substrates to form parallel reference surfaces of the elements of the thin film magnetic head, and cutting the substrate on which the reference surface is formed into predetermined blocks in parallel with the reference surface. Cutting step to
And a step of bringing the reference surface of the block into close contact with a jig having a highly accurate flat surface and fixing the block brought into close contact with the jig until processing is completed.

In order to achieve the above-mentioned second object, the structure of the second invention relating to the method of processing a thin film magnetic head is a substrate in which a large number of elements of the thin film magnetic head are formed in the method of processing a thin film magnetic head. A step of cutting the substrate into blocks in parallel with the reference surface while forming a reference surface parallel to the element of the thin film magnetic head by grinding the end surface of the block, and a jig having a highly accurate flat reference surface of the block. And the step of adhering the block adhered to the jig until the processing is completed.

In order to achieve the above-mentioned third object, the structure of the third invention relating to the processing apparatus for a thin film magnetic head is the processing apparatus for manufacturing a thin film magnetic head from a substrate on which a large number of head elements are formed. Provided with a grinding wheel and a cutting wheel, the grinding wheel has a diameter larger than a value obtained by adding at least twice the thickness of the substrate to the diameter of the cutting wheel,
The two grindstones are arranged such that their processed surfaces face each other and are attached to the same drive shaft, and their intervals are adjusted to the cutting pitch of the substrate.

[0016]

The function of each of the above technical means is as follows. According to the configuration of the first invention, a reference surface grinding step of grinding the end surface of the substrate to form a reference surface parallel to the element of the thin film magnetic head, and a cutting step of cutting the substrate into blocks in parallel with the reference surface. Since the reference surface is brought into close contact with a jig having a highly accurate flat surface, and this block, which is brought into close contact with the jig, is fixed until the completion of processing, the substrate before the cutting step is thick, That is, since the rigidity of the substrate is proportional to the cube of its thickness, the substrate can be ground in a state where the rigidity of the substrate is high, and the reference plane can be ground parallel to the array of elements to form a highly accurate plane. To be done. Therefore, the amount of deformation of the head element array after grinding becomes small, and the amount of deformation with respect to the same force also becomes small.
The step of grinding the reference surface, which must be peeled off, is unnecessary, and the steps can be simplified and the cost can be reduced.

If a block is cut parallel to the reference plane from a substrate having a reference plane parallel to the array of head elements, a block with a small amount of deformation of the head array can be obtained. Furthermore, if the reference surface of the block cut in the cutting process is fixed in close contact with a jig having a highly accurate flat surface, even if the head element array is deformed due to internal stress on the processed surface at the time of cutting, It is corrected by a jig having a plane of accuracy, the deformation amount of the head element arrangement can be corrected, and the head elements are arranged in a straight line. Furthermore, in the contacting step, since the blocks having a small deformation amount in the head element array are fixed in contact, the precision processing can be performed in the air bearing surface polishing step, the individual head cutting step, and the like.

According to the configuration of the second invention, since the grinding step and the cutting step in the configuration of the first invention are performed at the same time, better and accurate machining can be smoothly carried out. Produces the same effect as that of the first invention,
The man-hour can be reduced.

According to the structure of the third aspect of the invention, the diameter of the grinding wheel is larger than the diameter of the cutting wheel, both wheels are arranged facing each other and mounted on the same drive shaft, so that the direction of processing progresses. On the other hand, grinding of the grinding wheel precedes, and the end surface of the substrate having high rigidity before cutting by the cutting wheel is ground, and accurate precision processing and man-hours can be reduced as in the first and second inventions. Further, the cutting pitch of the substrate can be freely adjusted by adjusting the interval between both grindstones.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment of the present invention will be described below with reference to FIGS. [Embodiment 1] FIG. 1 is a flow chart for explaining a main part of a method of processing a thin film magnetic head according to an embodiment of the present invention. The processing method of this embodiment according to the first aspect of the present invention is the method of processing a magnetic head, comprising: a reference surface grinding step [1] of grinding an end surface of a substrate to provide a reference surface parallel to an array of elements of a thin film magnetic head; A cutting step [m] for separating the substrate into blocks parallel to the reference plane, and a contacting step [n] for fixing the reference surface of the separated block to a jig having a highly precise flat surface and fixing the block until processing is completed. ] And are provided.

In FIG. 1, 1 is a cutting grindstone, 2 is a substrate on which many thin film magnetic head elements are formed, 3 is an element of the thin film magnetic head, 4 is a block separated from the substrate, and 5
Is a reference surface, 6 is a jig, 7 is wax, 8 is an end surface of the substrate,
9 is a cup grinding wheel. As shown in FIG. 1, in the reference surface grinding step [l], the end surface 8 of the substrate 2 is ground by a cub grinding wheel 9 to obtain straightness and the reference surface 5 is formed.
That is, since the rigidity of the substrate is proportional to the cube of its thickness, if the substrate is ground in a highly rigid state, the substrate 2
Since the end surface 8 can be ground parallel to the arrangement of the magnetic head elements 3, the reference surface 5 parallel to the arrangement of the head elements 3 can be formed.

Next, in the cutting step [m], the substrate 2 on which the reference plane 5 is formed is cut by the cutting grindstone 1 in parallel with the reference plane 5 to separate the block 4. The separated block 4 is a block in which the amount of deformation of the head element array is small. In the jig contacting step [n], the block 4 having a small amount of deformation of the separated head element array is directly stuck and fixed to the jig 6 having a highly accurate flat surface.
Therefore, even if the head element array is deformed by the internal stress of the machined surface at the time of cutting, the jig 6 has a highly accurate flat surface and is corrected. Therefore, the subsequent processing steps, that is, the forming and grinding step of forming the slider rail of the thin film magnetic head, the air bearing surface polishing step of the thin film magnetic head, and the individual head cutting step can be processed accurately and quickly. Finally, after all the processing is completed, the individual magnetic head element cut from the jig 6 is peeled off. By these steps, a complicated jig adhering step [t] for grinding, a peeling step [v], etc., which are required in the conventional processing method, are unnecessary, and the number of steps is reduced and the yield of the magnetic head is improved. The performance of the head can be improved.

[Embodiment 2] Next, embodiments of the second and third inventions will be described together. FIG. 2 is an explanatory view of a main part flow chart of a method of processing a thin film magnetic head according to another embodiment of the present invention, and FIG. 3 is a grindstone of an apparatus used in the method of processing the thin film magnetic head of FIG. 6 is a cross-sectional view of a holding body 11. FIG. In FIG. 2 and FIG. 3, the same reference numerals as those in FIG. In FIG.
Reference numeral 11 is a grindstone holder, 12 is a flange, 13 is a cutting grindstone cover, 14 is a spacer a, 15 is a spacer b, 16 is a spacer c, and 17 is a stopper lid.

In the grindstone holding body 11, the cutting grindstone 1 is disposed between the flange 12 and the cutting grindstone cover 13, and the cup grinding grindstone 9 has the grinding surface 9a facing the cutting grindstone 1 and the above-mentioned cutting. Whetstone cover-13, spacer a14,
It is provided between the spacer b15 and the spacer c16. The above-mentioned members are attached to the flange 12 by the stopper lid 17.
Is fastened to. The shaft hole 20 of the flange 12 is attached to a spindle (not shown) of the grinder.

The diameter of the cup grindstone 9 is larger than the diameter of the cutting grindstone 1 by at least twice the thickness of the substrate 2. This is because unless the diameters of the two are more than twice the thickness of the substrate 2, a part of the substrate is cut before the grinding process is finished and the rigidity of the substrate 2 being ground becomes small. This is to prevent Further, in the grindstone holder 11, the spacer a14, the spacer b15, and the spacer c16 are exchanged, and the distance between both grindstones can be adjusted by changing the thickness thereof. Therefore, the interval between the cup grinding wheel 9 and the cutting wheel 1 can be freely changed according to the cutting width of the substrate 2, the cutting amount of the reference surface grinding can be adjusted, and the cutting pitch can be changed.

Next, the function of this embodiment will be described.
Since the diameter of the cup grinding wheel 9 is larger than the diameter of the cutting wheel 1, the cutting direction is different by the difference between the diameters.
That is, the cup grinding wheel 9 precedes the grinding direction. Since the diameter between the two grindstones is more than twice the thickness of the substrate 2, the cutting grindstone 1 is not cut until the grinding is completed. Therefore, the head element 3
Can be ground in a straight state, and similarly to [Example 1], a block 4 with a small amount of deformation of the head element array is formed, and is directly adhered to the jig 6 for polishing. Forming and grinding process, polishing process of air bearing surface, then,
The individual head cutting process can be performed accurately. The stopper lid 17 is removed from the flange 12, and the spacers a14 and spacers are sandwiched between the cutting grindstone 1 and the cup grinding grindstone 9.
Other spacers with different thicknesses are used for the spacer b15 and spacer c16.
The cutting grindstone 1, the cup grinding grindstone 9, and the spacers are fastened to the stopper lid 17 again. In this way, the distance between the two grindstones is adjusted, and the thickness of the block can be freely changed. As a result, the yield of the magnetic head can be improved and the performance of the head can be further improved. In addition, at the same time, the number of steps can be reduced.

A specific numerical example in this embodiment will be described below. In Figure 2, thickness 4mm, length 50m
m alumina ceramics 2, grain size # 600, outer diameter φ
100 mm, blade thickness 0.28 mm electroformed diamond cutting whetstone 1 and grain size # 800, whetstone end surface outer diameter φ1
A cup grindstone 9 having a diameter of 08 mm and an inner diameter of the grindstone of 102 mm was ground and cut using a device attached to the same spindle of a grinder via a grindstone holder 11. In this case, the cutting amount of the reference surface grinding of the cup grinding wheel 9 is 15μ
m, the grindstone rotation speed is 5000 rpm, and the work feed rate is 15 mm / min, and the feed rate is 100 mm / mi.
There were two sparkouts of n. The block 4 separated from the substrate of the material to be ground in this manner is adhered to the jig 6 using the wax 7 and the element deformation amount is measured to be 0.3 μm.
m / 50 mm could be obtained. As is clear from this numerical value, the block 4 with a small amount of deformation of the head element array is created, and the man-hour can be reduced, the yield of the magnetic head can be improved, and the performance of the head can be further improved.

[0028]

As described in detail above, according to the present invention, firstly, before cutting the block from the substrate, the end face of the substrate having a high rigidity is ground by a grinding wheel to achieve high precision. Since the reference surface is formed and then cut into blocks, the amount of deformation of the head element array is reduced, and a block that can be subjected to accurate precision processing is created, a flat air bearing surface, a gap shape with good mechanical accuracy and a shallow gap depth. It is possible to provide a processing method in which a thin film magnetic head having the following is manufactured, a simple process is performed, and cost is reduced.

Secondly, it is possible to provide a method of processing a thin film magnetic head, which achieves the first object of the present invention and shortens the number of steps by simultaneously performing the grinding step and the cutting step and further advancing. it can.

Further, thirdly, there is provided a substrate processing apparatus for a thin-film magnetic head, which is provided with a grinding wheel and a cutting wheel and which simultaneously performs the cutting step and the grinding step, which are the second object of the present invention, to reduce the number of steps. can do.

[Brief description of drawings]

FIG. 1 is a flow chart illustrating the main part of a method of processing a thin film magnetic head according to an embodiment of the present invention.

FIG. 2 is a flow chart illustrating the main part of a method of processing a thin film magnetic head according to another embodiment of the present invention.

3 is a cross-sectional view of a grindstone holder 11 of an apparatus used in the method of processing the thin film magnetic head of FIG.

FIG. 4 is a flowchart for explaining a main part of a conventional method of processing a thin film magnetic head.

5 is a structural diagram of a thin film magnetic head H. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cutting grindstone 2 Substrate on which many thin film magnetic head elements are formed 3 Thin film magnetic head element 4 Block 6 Air bearing surface grinding jig 7 Wax 9 Cup grinding grindstone 11 Grindstone holder 12 Flange 13 Cutting grindstone cover 14 Spacer a 15 Spacer b 16 Spacer c 17 Stopper lid 18 Slider rail

Claims (3)

[Claims] 1. A method of processing a thin film magnetic head, comprising a reference surface grinding step of grinding an end surface of a substrate on which a large number of elements of the thin film magnetic head are formed to form a reference surface parallel to an array of elements of the thin film magnetic head. , A cutting step of cutting the substrate on which the reference surface is formed into a predetermined block in parallel with the reference surface, and closely adhering the reference surface of the block to a jig having a highly precise flat surface until the processing is completed. A method of processing a thin-film magnetic head, comprising a fixing step of fixing. 2. In a method of processing a thin film magnetic head, an end surface of a substrate on which a large number of elements of the thin film magnetic head are formed is ground to form a reference plane parallel to the array of elements of the thin film magnetic head, and this substrate is formed. It has a step of cutting into blocks in parallel with the reference surface, and a step of adhering the reference surface of the block to a jig having a highly accurate flat surface and fixing the block until completion of processing. Processing method of thin film magnetic head. 3. A processing apparatus for producing a thin film magnetic head from a substrate on which a large number of head elements are formed, comprising a grinding grindstone and a cutting grindstone, the grinding grindstone having a diameter of the cutting grindstone of at least the thickness of the substrate. Has a diameter larger than a value obtained by adding twice or more of the above, and the two grinding wheels are arranged such that their processing surfaces face each other and are mounted on the same drive shaft, and the distance between them is the cutting pitch of the substrate. An apparatus for processing a thin film magnetic head substrate, which is characterized in that: