JPH0640371B2 - Coil structure of thin film magnetic head - Google Patents

Description

The present invention relates to a coil structure of a thin film magnetic head which is arranged in contact with a magnetic recording medium and reads a magnetic flux change caused by the magnetic recording medium sent at a predetermined speed as an induced current generated in a coil. , More specifically, 2 coils on the substrate
The present invention relates to a coil structure formed by stacking layers.

An inductive thin film magnetic head is known as a means for recording voice information and the like on a magnetic recording medium (for example, a magnetic tape) and reading and reproducing the information recorded on the magnetic recording medium.
An example of this inductive thin film magnetic head is shown in FIGS.
There is something like the one shown in the figure. 1 is a front view of the thin film magnetic head, and FIGS. 2 and 3 are arrows A shown in FIG.
It is sectional drawing which cuts and shows a thin film magnetic head along -A and BB. The coil terminal 4 and the lower magnetic pole 5 provided on the substrate 1 are covered with a first insulating layer 6, and the first insulating layer 6 is formed.
A very thin coil 3 is formed on the top surface of the coil by photoetching or the like. The outermost end 3b of the coil 3 is electrically connected to the outside, and the innermost end 3a penetrates the first insulating layer and is connected to the coil terminal 4. A second insulating layer 7 covering the entire first insulating layer 6 including the coil 3 is provided, and one end 2a penetrates the first insulating layer 6 and the second insulating layer on the second insulating layer 7. An upper terminal 2 connected to one end 5a of the lower magnetic pole 5 is provided, and the entire second insulating layer 7 including the upper terminal 2 is covered with a protective layer 8 to form a thin film magnetic head.

When the magnetic tape is fed in contact with the lower end 10 of the thin film magnetic head and perpendicular to the paper surface in FIG. 1, magnetic fields from the magnetic tape generate magnetic fields in the upper magnetic pole 2 and the lower magnetic pole 5, and The magnetic flux in this magnetic pole changes according to the recorded information. This change in magnetic flux causes the coil 3
An induced current is generated in the magnetic field, and the information recorded on the tape can be read by extracting and detecting the induced current from the coil terminal 4 and the outermost end 3b of the coil.
The principle when recording information on a magnetic tape is completely opposite to the above, and the information converted into the change in current is sent to the coil 3,
A magnetic flux is generated in the upper magnetic pole 2 and the lower magnetic pole 5, and the change in the magnetic flux is recorded on the magnetic tape.

As described above, it is possible to read (reproduce) information from the magnetic tape or the like by the thin film magnetic head and record the information to the magnetic tape or the like, but it is possible to increase the induced current generated in the coil. If possible, reading and recording can be performed more accurately, which is convenient. In order to increase the induced current generated in the coil with respect to the same change in magnetic flux, the number of turns of the coil should be increased, and the coil portion sandwiched between the upper magnetic pole 2 and the lower magnetic pole 5 should be as close to the magnetic tape as possible. It is effective. In this case, if the number of turns of the coil is increased as it is, the winding diameter of the coil is expanded outward and the head becomes large, which is not preferable. From this point, a structure in which the coils are provided in two layers is used. Often.

An example of a two-layer coil structure is shown in FIGS. 4 to 6. FIG. 4 is a front view, and FIGS. 5 and 6 are cross-sectional views taken along arrows C-C and D-D shown in FIG. In this case, the lower magnetic pole 5 is provided on the substrate 1, the first insulating layer 11 is provided so as to cover the lower magnetic pole 5, and the lower coil wire 31 is formed on the first insulating layer 11 by photoetching or the like. To provide. Next, after covering the entire first insulating layer 11 including the first layer coil layer 31 with the second insulating layer 12 and providing the upper coil wire 32 on the second insulating layer 12 by photoetching or the like, This is covered with the third insulating layer 13. Further, an upper magnetic pole 2 is provided so as to straddle the lower and upper coil wires 31, 32, and one end 2a of the upper magnetic pole 2 is connected to one end 5a of the lower magnetic pole. Further, the entire third insulating layer including the top pole 2 is covered with the protective layer 8.

With the coil structure as described above, the number of turns can be increased without increasing the winding diameter of the coil, so that the induced current generated for the same change in magnetic flux can be increased.

On the other hand, in order to record a large amount of information on one tape, it is required to reduce the size of the head, especially the track width as much as possible as the number of heads used increases and the number of channels increases. It is required that the thickness is as small as 5 to 10 μm and the thickness of the insulating layer is also extremely thin. Therefore, normally, a thin film head is made by forming an insulating layer as a layer having a substantially uniform thickness by high frequency sputtering or the like, and forming a conductive layer coated on this layer into a coil shape by photoetching. There are many. At this time, the lower coil wire 31
The second insulating layer 12 which covers is formed as a layer having a substantially uniform thickness by sputtering or the like, and therefore rises on the upper surface of the lower coil wire 31 to cause unevenness on the entire surface. Therefore, the second
When forming the upper coil wire 32 on the insulating layer 12, it is necessary to coat a conductive layer on the surface having irregularities and form the coil shape by photoetching. In particular, when the coils are formed in two layers, if the winding directions are reversed, the induced currents flow in opposite directions and cancel each other. Therefore, the winding directions must be the same. Therefore, as shown in FIG. 4, the first layer coil 31 and the second layer coil 32 must be crossed at a rate of once per turn. Therefore, especially when photoetching is performed at the crossing portion. The following problems occur. For example,
As shown in FIG. 6 which is a cross section of the portion where the first layer coil 31 and the second layer coil 32 overlap, when the coil layer is left in the convex portion b and the coating layer must be removed by etching in the concave portion a. However, if the recess a is too narrow, the photoresist thickness becomes uneven, and the exposure / development conditions become difficult, so that there is a problem in that the pattern formation by photolithography is not successful. Further, in the case of performing dry etching, if the recess is too narrow, there is a problem that the shadow due to the protrusion is generated and it is difficult to etch the entire recess, and the coil is short-circuited due to the remaining portion.
However, in order to make the recesses infinitely wide, the distance between the coils must be increased, which increases the overall size of the thin-film magnetic head, which is not very preferable.

In view of the above circumstances, it is an object of the present invention to provide a thin film magnetic head having a two-layer coil structure in which the recess is as wide as possible and the size of the entire head is as small as possible. In particular, considering that the size requirements are slightly different between a single-channel type that uses only one head and a multi-channel type that uses multiple heads, a head suitable for single-channel use and a multi-channel type It is intended to provide a head suitable for use.

The coil structure of the thin film magnetic head of the present invention is a thin film in which a rectangular upper coil wire having the same winding direction as the lower coil wire is provided on a rectangular lower coil wire provided on a substrate through an insulating layer. In a magnetic head, the upper and lower coil wires forming a side close to the magnetic recording medium that is sent in contact with the head and generates an induced current in the upper and lower coil wires are alternately arranged close to each other, and The upper and lower coil wires forming the two sides adjacent to the adjacent side are alternately spaced apart from each other, and the upper and lower coil wires forming the side facing the adjacent side are spaced apart from each other. It is characterized in that the upper coil wire and the lower coil wire are overlapped in the vicinity of the apex corners of both ends of the opposite sides. (This is referred to as Structure 1.) Furthermore, the coil structure of the thin film magnetic head of the present invention is a thin film magnetic in which the upper coil wire is provided on the lower coil wire provided on the substrate via the insulating layer in the same manner as described above. In the head, upper and lower coil wires forming two adjacent sides including a side adjacent to the magnetic recording medium are alternately arranged in close proximity, and upper and lower coil wires forming the other two sides are alternately arranged. It is characterized in that the upper coil wire and the lower coil wire are arranged apart from each other, and in the vicinity of the apex angle portion where the other two sides intersect. (This will be referred to as Structure 2) Hereinafter, the embodiments of the present invention will be described with reference to the drawings, and the effects of the present invention will be described.

FIG. 7 is a front view showing an embodiment of the former invention (invention of structure 1), in which the first insulating layer is formed on the substrate 1 having the lower magnetic pole by high frequency sputtering or the like, and the lower portion is formed thereon. The coil wire 41 is provided by photoetching or the like. Next, a second insulating layer covering the entire first insulating layer including the lower coil wire 41 is formed by high frequency sputtering or the like, and an upper coil wire 42 is formed thereon by photoetching or the like.
This is covered with a third insulating layer, the upper magnetic pole 2 is provided, and then the entire surface is covered with a protective layer. At this time, the upper and lower coil wires 41a, 42a forming a side close to the head lower end portion 40 contacting a magnetic recording medium such as a magnetic tape are arranged such that the upper coil wire 41a and the lower coil wire 42a are alternately arranged close to each other, By making the magnetic recording medium as close to the magnetic recording medium as possible, the induced current generated by the magnetic flux change of the magnetic field generated in the upper magnetic pole 2 and the lower magnetic pole is increased. Further, the lower coil wires 41b and 41d and the upper coil wires 42b and 42d that form two sides adjacent to the lower and upper coil wires 41a and 42a that form the adjacent side have the lower coil wire and the upper coil wire alternately separated from each other. And the lower and upper coil wires 41c, 42c, which form a side facing the adjacent side, are arranged apart from each other,
Overlapping portions 43 to 46 of the lower coil wire 41 and the upper coil wire 42 are arranged near both ends of the opposite sides 41c and 42c. In this way, the recesses d, e, f adjacent to the overlapping portions 43 to 46 are widened, and the etching for forming the upper coil wire 42 is facilitated.

In the case of the present embodiment (Structure 1), the length of the head in the width direction becomes long, so that it is not suitable for use for multiple channels, and is preferable for single channels.

FIG. 8 is a front view showing an embodiment of the invention of structure 2, and particularly this embodiment shows an example suitable for use for multi-channel. A lower magnetic pole is provided on the substrate 1 so as to overlap with the upper magnetic pole 2 in the same shape, a first insulating layer is formed on the substrate 1 by high frequency sputtering or the like, and a lower portion is formed on the upper surface of the first insulating layer by photoetching or the like. The coil wire 51 is formed. Next, a second insulating layer including the lower coil wire 51 and covering the entire first insulating layer is formed by high frequency sputtering or the like, and an upper coil wire 52 is formed thereon by photo-etching or the like. After providing the third insulating layer, the upper magnetic pole 2 is provided and the entire surface is covered with the protective layer. When the thin-film magnetic head is constructed in this manner, upper and lower coil wires 51a, 5a forming a side close to the lower end 50 contacting the magnetic recording medium.
2a and upper and lower coil wires 51b and 52b forming one side adjacent to the adjacent side are arranged so that the upper coil wire and the lower coil wire are alternately adjacent to each other. Further, in the adjacent side and two sides other than the adjacent side,
The upper coil wire and the lower coil wire are alternately arranged apart from each other, and the overlapping portions 53 to 57 of the upper coil wire and the lower coil wire are arranged near the apex angle portion where the other two sides intersect. In this way, the recesses g, h, i in the vicinity of the overlapping portion can be widened and photoetching can be facilitated. In this embodiment,
Since the overlapping portions 53 to 57 are located on one side and the coil wires forming the two sides of the rectangular shape are close to each other, the width of the head can be reduced, and for multi-channel use where a large number of heads are arranged in parallel. Are suitable.

In particular, as shown in the drawing, the upper magnetic pole 2 and the lower magnetic pole are provided with two thin film magnetic heads which are inclined from the center of the coil toward the side where the coil wires 51b, 52b are located. If the side where the 52b is located is used so as to face each other, the upper magnetic pole 2 and the lower magnetic pole at the lower end 50 of the head come closer to each other, and the required width of the magnetic recording medium can be reduced. As described above, the structure 2 is suitable for multi-channel use, and particularly suitable for 2-channel use.

As described above, according to the thin-film magnetic head having the structure of the present invention, the coil wires sandwiched between the upper magnetic pole and the lower magnetic pole are arranged close to each other, so that the induced current with respect to the magnetic flux change can be increased. In addition to being able to widen the concave and convex portions produced when making the two-layer coil, it is possible to loosen the exposure conditions for photoetching.
Photoetching for forming the two-layer coil is easy.

[Brief description of drawings]

FIG. 1 is a front view of a conventional thin film magnetic head, and FIGS. 2 and 3 are cross-sectional views showing the thin film magnetic head taken along arrows AA and BB in FIG. 1, respectively. FIG. 4 is a front view of a conventional thin film magnetic head having a two-layer coil, and FIGS. 5 and 6 are cross-sectional views of the thin film magnetic head taken along arrows C-C and D-D in FIG. 4, respectively. FIGS. 7, 7 and 8 are front views showing an embodiment of the thin film magnetic head of the present invention. 1 ... Substrate 2 ... Upper magnetic pole 5 ... Lower magnetic pole 8 ... Protective layer 31,41,51 ... Lower coil wire 32,42,52 ... Upper coil wire

Claims (2)

[Claims] 1. A quadrangle from the inside to the outside having a winding direction that is the same as that of the lower coil wire on the lower coil wire provided on the substrate and wound in a square shape from the outer side to the inner side through an insulating layer. In a thin film magnetic head for reading a magnetic field change due to a magnetic recording medium sent in contact as an induced current, a side of the lower coil line and the upper coil line which is close to the magnetic recording medium is provided. The coil wires are alternately arranged close to each other, and the lower coil wire and the upper coil wire forming two sides adjacent to the adjacent side are alternately spaced apart from each other, and the side opposite to the adjacent side. The lower coil wire and the upper coil wire forming the above are separated from each other, and the lower coil wire and the upper coil wire overlap each other in the vicinity of the apex corners of both ends of the facing side. Coil structure of the thin film magnetic head is characterized. 2. A quadrangle from the inside to the outside having a winding direction that is the same as that of the lower coil wire on the lower coil wire provided on the substrate and wound in a square shape from the outer side to the inner side through an insulating layer. In a thin film magnetic head for reading a magnetic field change due to a magnetic recording medium sent in contact as an induced current, a side of the lower coil line and the upper coil line which is close to the magnetic recording medium is provided. The coil wires forming the two adjacent sides including the coil wires are arranged alternately close to each other, and the coil wires forming the other two sides are arranged alternately apart from each other, and in the vicinity of the apex angle portion where the other two sides intersect. A coil structure of a thin-film magnetic head, wherein the lower coil wire and the upper coil wire are overlapped with each other.