Method of manufacturing a head assembly

Abstract

A head assembly for use in a VCR includes a head base, a head chip comprised of a first non-magnetic substrate block, a magneto-resistive head, a thin film head, and a second non-magnetic substrate block, an FPCB attached to the magneto-resistive head, and an FPCB attached to the thin film head. Such a head assembly can record or reproduce high density magnetic signals by virtue of the very small magnetic gaps incorporated therein. Such a head assembly can be manufactured by forming the magneto-resistive and thin film heads on a substrate wafer using layering processes. In the alternative, the magneto-resistive head and the thin film head can be formed on separate substrate wafers by using layering processes, and then combined to produce a head chip.

Description

FIELD OF THE INVENTION

The present invention relates to a head assembly for use in a video cassette recorder ("VCR"); and, more particularly, to a head assembly capable of recording and reproducing magnetic signals at high densities, and to a method for the manufacture thereof.

DESCRIPTION OF THE PRIOR ART

As is well known, a VCR is equipped with a head assembly for reproducing signals previously recorded on a video cassette, as well as for recording new signals thereon.

There is shown in FIG. 1 a prior art head assembly 1 comprising a head base 9 installed on a rotary drum (not shown), and a head chip 2 attached thereto and composed of an "I" shaped ferrite core 3 and a "C" shaped ferrite core 4, glued to each other at their posterior portions by a glass layer 6 while forming at their anterior end a magnetic gap 5.

Such a head assembly functions by reading a magnetic signal recorded on a magnetic tape (not shown) through the magnetic gap 5. As the magnetic gap 5 is moved near the magnetic tape, a magnetic field of the recorded signal causes a reordering of a plurality of magnetic dipoles present in the ferrite cores 3, 4. This, in turn, causes a change in the magnetic flux, inducing an electric signal in a coil 8 threaded around the "C" shaped ferrite core 4 through a wire coil groove 7 provided therein. This electric signal is then provided to the rotor transformer (not shown) to be passed on to other parts of the VCR.

Alternatively, during a recording operation, an electric signal is applied to the coil 8, causing the magnetic dipoles of the ferrite cores 3, 4 to realign. This generates a magnetic field around the magnetic gap 5, which is used to record a magnetic signal on the magnetic tape.

The amount of signals that can be recorded on a set length of the magnetic tape, i.e. a signal density, depends on the width of the magnetic gap. By narrowing the magnetic gap, it is possible to record a magnetic signal that takes up a correspondingly smaller length of the tape (a `finer` signal). Likewise, by narrowing the magnetic gap, it is possible to improve the ability of the VCR to discriminate between finer signals during the read operation. Thus, the signal density depends on the width of the magnetic gap 5.

However, the conventional head assembly described above suffers from the disadvantage that the width of the magnetic gap 5 cannot be reduced beyond 0.3 .mu.m. The magnetic gaps are conventionally formed by mechanical processes such as trimming or grinding, and with currently available techniques it is not possible to fashion a magnetic gap narrower than 0.3 .mu.m.

Furthermore, the conventional head assemblies are not sensitive enough to make reproduction of signals recorded at high densities practical. As the magnetic gap is made narrower and a surface area of the magnetic tape taken up by a signal is reduced, the magnetic field generated by the signal decreases correspondingly. Thus, even if the magnetic gap of the conventional head assembly could be made narrower than 0.3 .mu.m, the fact that there is a limit to how small the surface area of the tape taken up by each magnetic signal can be to be detectable by the conventional head assembly composed of ferrite cores places a limit on the signal density that can be achieved.

Although this problem can theoretically be resolved by increasing a rotational speed of the rotary drum on which the head assembly is installed, this solution is inconvenient and restricted by a practical limitation on how fast the rotary drum can be made to rotate.

SUMMARY OF THE INVENTION

It is, therefore, a primary object of the present invention to provide a head assembly for use in a VCR capable of recording and reproducing magnetic signals at high densities.

It is another object of the present invention to provide a method for the manufacture a head assembly for use in a VCR capable of recording and reproducing magnetic signals at high densities.

In accordance with one aspect of the present invention, there is provided a head assembly for use in a VCR comprising: a first non-magnetic substrate block; a first magnetic core, a first insulating layer, a magneto-resistive core, a pair of conducting plates, and a second insulating layer forming a magneto-resistive head; a second magnetic core, a third insulating layer, a conducting coil, a fourth insulating layer, a third magnetic core, and a fifth insulating layer forming a thin film head; a second non-magnetic substrate block; a head base; and two flexible circuit boards ("FPCB"), one FPCB being attached to the conducting plates and the other being attached to the conducting coil, each provided with a notch to facilitate installation on the head base.

In accordance with another aspect of the present invention, there is provided a method for the manufacture of a head assembly for use in a VCR comprising the steps of: providing a non-magnetic substrate wafer; depositing a first magnetic layer on top of the non-magnetic substrate wafer, thereby giving rise to a first magnetic core; forming a first insulating layer on top of the first magnetic core; depositing a magneto-resistive layer on top of the first insulating layer; removing portions of the magneto-resistive layer formed on top of the first insulating layer to thereby give rise to a magneto-resistive core; depositing a conducting layer on top of the magneto-resistive core and the first insulating layer; removing portions of the conducting layer formed on top of the magneto-resistive core and the first insulating layer thereby giving rise to a pair of conducting plates; forming a second insulating layer on top of the magneto-resistive core and the pair of conducting plates, thereby giving rise to a plurality of magneto-resistive heads each comprised of the first magnetic core, the first insulating layer, the magneto-resistive core, the pair of conducting plates, and the second insulating layer; depositing a second magnetic layer on top of the second insulating layer; removing portions of the second magnetic layer formed on top of the second insulating layer thereby giving rise to the second magnetic core; depositing a third insulating layer on top of the second magnetic core and the second insulating layer; depositing a conducting coil layer on top of the third insulating layer; removing portions of the conducting coil layer deposited on top of the third insulating layer to thereby give rise to a conducting coil; forming a fourth insulating layer on top of the third insulating layer and the conducting coil; removing portions of the fourth insulating layer and the third insulating layer formed on top of the second magnetic core; depositing a third magnetic layer on top of the fourth insulating layer while filling in the gaps left by the removed portions of the fourth insulating layer and the third insulating layer; removing portions of the third magnetic layer formed on top of the fourth insulating layer to thereby give rise to a third magnetic core; forming a fifth insulating layer on top of the third magnetic core and the fourth insulating layer to thereby give rise to a plurality of thin film heads each comprised of the second magnetic core, the third insulating layer, the conducting coil, the fourth insulating layer, the third magnetic core, and the fifth insulating layer; slicing the non-magnetic substrate wafer and the layers deposited thereon into a plurality of slices, each comprised of a row of magneto-resistive heads and thin film heads; affixing a second non-magnetic substrate block layer on top of the thin film heads; cutting each slice into separate head chips each comprising a first non-magnetic substrate block, a magneto-resistive head, a thin film head, and a second non-magnetic substrate block; attaching two FPCB's to each head chip, one FPCB being attached to the magneto-restrictive head, and the other FPCB being attached to the thin film head; and installing each of the head chips manufactured as described above on a head base, to thereby yield a head assembly for use in a VCR.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 presents a perspective view of a conventional head assembly for use in a VCR;

FIGS. 2A and 2B are schematic cross sectional views illustrating the structure of a head assembly in accordance with an embodiment of the present invention;

FIGS. 3A to 3X are schematic cross sectional views illustrating a method for the manufacture of a head assembly in accordance with an embodiment of the present invention;

FIG. 4A sets forth a partially detailed perspective view illustrating a method for the manufacture of a head assembly in accordance with an embodiment of the present invention;

FIGS. 4B and 4C are perspective views illustrating a method for the manufacture of a head assembly in accordance with an embodiment of the present invention;

FIGS. 5A and 5B present schematic cross sectional views illustrating the structure of a head assembly in accordance with another embodiment of the present invention;

FIGS. 6A to 6X, 6C-1 and 6C-2 present schematic cross sectional views illustrating a method for the manufacture of a head assembly in accordance with another embodiment of the present invention;

FIGS. 7A and 7B set forth partially detailed perspective views illustrating a method for the manufacture of a head assembly in accordance with another embodiment of the present invention;

FIGS. 7C to 7F are perspective views illustrating a method for the manufacture of a head assembly in accordance with another embodiment of the present invention;

FIG. 8A sets forth a perspective view illustrating a method for the manufacture of a head assembly in accordance with the present invention;

FIGS. 8B and 8C are schematic views illustrating a method for the manufacture of a head assembly in accordance with the present invention; and

FIG. 9 is a perspective view illustrating a head chip and a pair of flexible printed circuit boards for use in a head assembly in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, the horizontal left to right dimension of the components is expressed as their width and the anterior (i.e. the side that ends up contacting a magnetic tape) to posterior dimension is expressed as the length. It should also be noted that like parts appearing in the figures are represented by like reference numerals.

Referring to FIGS. 2A and 2B, there are shown, respectively, a lateral and a frontal cross sectional views of a head chip 30 of a head assembly for use in a VCR according to a preferred embodiment of the present invention. The head chip 30 includes a first non-magnetic substrate block 11; a magneto-resistive head 17; a thin film head 26; and a second non-magnetic substrate block 31.

The first and the second non-magnetic substrate blocks 11, 31 serve to provide protection against physical damage to the magneto-resistive head 17 and the thin film head 26. The non-magnetic substrate blocks are composed of a non-magnetic material, e.g., Al.sub.2 O.sub.3.

The magneto-resistive head 17 is positioned on top of the first non-magnetic substrate block 11, and is composed of a first magnetic core 12, a first insulating layer 13 placed on top of the first magnetic core 12, a magneto-resistive core 14 flanked by a pair of conducting plates 15 which slightly overlap both sides thereof, and a second insulating layer 16. A separation between the first magnetic core 12 and the magneto-resistive core 14 constitutes a magnetic gap 18 included in the magneto-resistive head 17 to allow it to read magnetic signals recorded on a magnetic tape (not shown). At this point, it should be mentioned that a thickness of the first insulating layer 13 corresponds to a width of the magnetic gap 18.

The first magnetic core 12 is located on a top surface of the first non-magnetic substrate block 11. The first insulating layer 13 is in turn located on a top surface of the first magnetic core 12. The magneto-resistive core 14, which has a flat, rectangular shape, is placed on a top surface of the first insulating layer 13 flush against an anterior edge thereof. The magneto-resistive core 14 is narrower (i.e. of a smaller width) than the first insulating layer 13, and the first insulating layer 13 extends to its left and right for equal distances. In addition, a posterior portion of the first insulating layer 13 is not covered by the magneto-resistive core 14 as the magneto-resistive core 14 is also shorter (i.e. of a smaller length) than the first insulating layer 13.

The two conducting plates 15 are located to the right and to the left of the magneto-resistive core 14. The conducting plates 15 are longer than the magneto-resistive core 14 and extend past a posterior end thereof. In addition, each of the conducting plates 15 is equipped with a raised, stepped portion that slightly overlaps the magneto-resistive core 14 to ensure good electrical connection therewith.

The second insulating layer 16 is located on a top surface of the magneto-resistive core 14, the conducting plates 15, and portions of the second insulating layer 13 not covered by the magneto-resistive core 14 or the conducting plates 15.

The thin film head 26, which is located on top of the magneto-resistive head 17, in turn includes a second magnetic core 21 and an "L" shaped third magnetic core 25, which contact each other at their posterior portions, leaving an elongated groove through which a conducting coil 23 is threaded, a third insulating layer 22 on a top surface of which the conducting coil 23 is located, a fourth insulating layer 24 which covers the conducting coil 23 and insures that there is no direct contact between the third magnetic core 25 and the conducting coil 23, and a fifth insulating layer 27 covering the third magnetic core 25 and portions of the fourth insulating layer 24. As with the magneto-resistive head 17, the thin film head 26 is provided with a magnetic gap 28 which allows it to record magnetic signals on the magnetic tape. A separation between the second magnetic core 21 and the third magnetic core 25 is equivalent to the width of the magnetic gap 28.

The second magnetic core 21 is located on a top surface of the second insulating layer 16 of the magneto-resistive head 17. The second magnetic core 21 is shorter and narrower than the second insulating layer 16, and is placed flush against a central part of an anterior edge thereof. Thus, as was the case with the magneto-resistive core 14 and the first insulating layer 13, the second magnetic core 21 leaves two strips of the second insulating layer 16 of equal width uncovered to its left and its right. A posterior portion of the second insulating layer 16 is left uncovered as well.

Meanwhile, the third insulating layer 22 is located on a top surface of the second magnetic core 21 and the top surface of the second insulating layer 16. The third insulating layer 22 covers the second magnetic core 21 and the second insulating layer 16 completely, except for a posterior portion of the second insulating layer 16 and a rectangular strip of the second magnetic core 21 through which the third magnetic core 25 contacts the second magnetic core 21.

The conducting coil 23 is shaped roughly like a series of concentric chain links and is located on a top surface of the third insulating layer 22. A posterior portion of the conducting coil 23 is divided by a gap, (i.e. the opening of the chain links) and is located on the top surface of the third insulating layer 22 posterior to the rectangular strip of the second magnetic core 21 which was left uncovered to allow contact with the third magnetic core 25. A continuous anterior portion of the conducting coil 23 is located anterior to the uncovered rectangular strip of the second magnetic core 21. In addition, the conducting coil 23 is wider than the second magnetic core 21 and the third magnetic core 25, such that a left and a right portions of the conducting coil 23 protrude past a left and a right sides of the second and third magnetic cores 21, 25.

The conducting coil 23 situated on the third insulating layer 22 as described above is in turn covered by the fourth insulating layer 24. The fourth insulating layer 24 covers the conducting coil 23 and the third insulating layer 22 completely, but leaving the rectangular strip of the second magnetic core 21 uncovered.

In turn, the third magnetic core 25 has a lateral cross section that looks like an "L" rotated ninety degrees clockwise. A short arm of the "L" is inserted into a gap left by the third and fourth insulating layers 22, 24 and contacts the uncovered rectangular portion of the second magnetic core 21. A long arm of the "L" is located on an anterior portion of the top surface of the fourth insulating layer 24 extending all the way to an anterior edge thereof, and leaving a posterior portion of the fourth insulating layer 24 exposed. The third magnetic core 25 has the same width as the second magnetic core 21, and is located directly above it, thus leaving a left and a right portion of the top surface of the fourth insulating layer 24 uncovered. The third magnetic core 25 and the fourth insulating layer 24 are in turn completely covered by the fifth insulating layer 27.

The second non-magnetic substrate block 31 is placed on top of the thin film head 26. The second non-magnetic substrate block 31 has a same width and a smaller length than the thin film head 26 and is placed flush against an anterior edge thereof, thus leaving a posterior strip of the thin film head 26 uncovered. It should be noted that a length and width of the first non-magnetic substrate block 11 correspond to a length and width of the magneto-resistive head 17, whereas the length of the thin film head 26 is smaller, and the length of the second non-magnetic substrate block is smaller still. Thus, the head chip 30 has a lateral profile that is roughly shaped like three steps. The first non-magnetic substrate block 11 and the magneto-resistive head 17 constitute one step, the thin film head 26 constitutes a second step, and the second non-magnetic substrate block 31 constitutes a third step. Furthermore, as illustrated in FIG. 4C, the head chip 30 has a frontal profile that is shaped like a parallelogram. In order to imbue the magnetic gaps 18, 28, with an azimuth angle, a left side and a right side of the head chip 30 are given a slight inclination.

In addition, two flexible printed circuit boards ("FPCB") 32 are attached to a posterior side of the head chip 30, one FPCB being attached to a rear of the magneto-resistive head 17 and being in electrical contact with the conducting plates 15, and the other being attached to a rear of the thin film head 26 and being in electrical contact with the conducting coil 23.

The head chip 30 structured as described above is installed on a head base 40 as shown in FIG. 8A. The head chip 30 is installed on an anterior portion of the top surface of the head base 40 while oriented horizontally, so that a side surface of the head chip 30 is in contact with the top surface of the head base 40. Also, the head chip 30 is facing outward, such that a frontal surface 50 of the head chip extends past the head base to facilitate interaction with a magnetic tape surface.

Thus, the magneto-resistive head 17 and the thin film head 26 are oriented vertically, (i.e. a plane formed by the lengthwise and widthwise directions of the heads 17, 26 is perpendicular to the top surface of the head base 40) such that the first magnetic core 12, the magneto-resistive core 14, the second magnetic core 21, and the third magnetic core 25 can all interact with the magnetic tape at once. Due to the slight inclination given to the sides of the head chip 30, the magneto-resistive head 17 and the thin film head 26 are also inclined slightly from a vertical line perpendicular to the top surface of the head base 40. This inclination gives the magnetic gaps 18, 28 their azimuth angles.

The magnetic gaps 18, 28 need to be provided with azimuth angles because magnetic signals on adjacent tracks of the magnetic tape are given different azimuth inclinations to prevent an occurrence of cross-talks. In other words, magnetic signals and magnetic gaps are given azimuth inclinations so that the magnetic gap can only read the signals recorded on the track that it is supposed to read.

Meanwhile, the two FPCBs 32 are twisted so that they have a parallel orientation in relation to the top surface of the head base 40 and attached thereto, allowing signals to be conveyed to and from the head chip 30.

The head base 40, in turn, is installed on a rotary drum 70, as shown in FIG. 8B. In addition, as illustrated by FIGS. 8A to 8C, the frontal surface 50 of the head chip 30 is given a slightly convex shape to allow the head chip 30 to interact better with the magnetic tape wrapped around the rotary drum 70.

The head assembly for use in a VCR as described above can read magnetic signals recorded on the magnetic tape by means of the magneto-resistive head 17 incorporated therein. When the magneto-resistive head 17 is brought to the proximity of the magnetic tape, a magnetic field emanating from the magnetic signal causes a change in a resistivity of the magneto-resistive core 14. This change in resistivity can be detected by measuring an electrical current running through the magneto-resistive core 14 and through the conducting plates 15.

Alternatively, recording operations can be carried out by the thin film head 26 included in the head assembly. During the recording operation, an electric signal is applied to the conducting coil 23, causing a plurality of magnetic dipoles present in the magnetic cores 21, 25 to realign. This generates a magnetic field around the magnetic gap 28, which can be used to record magnetic signals on the magnetic tape.

The head assembly for use in a VCR according to the preferred embodiment of the present invention can read and record high density magnetic signals by virtue of the magnetic gaps 18, 28 incorporated therein. Unlike conventional magnetic gaps, which are formed by mechanical processes such as grinding or trimming, and as a consequence cannot be produced with widths smaller than 0.3 .mu.m, the magnetic gaps 18, 28 incorporated in the inventive head assembly are formed by means of layering and etching processes. As a result, the magnetic gaps 18, 28 can be manufactured with widths in the hundreds of .ANG.'s (Angstroms) range, thus allowing proportionally smaller magnetic signals to be recorded or reproduced.

The smaller width of the magnetic gap 28 allows magnetic fields to be applied to a smaller portion of the magnetic tape at one time, thus allowing more magnetic signals to be recorded on a given length of magnetic tape. Conversely, the small width of the magnetic gap 18 allows the magneto-resistive head 17 to read the magnetic signal recorded on the smaller portion of the magnetic tape by the thin film head 26. This is made possible by the fact that although bigger magnetic gaps would end up reading many adjacent signals at once, the magnetic gap 18 is small enough to detect high density signals one signal at a time. In addition, the reproduction of high density signals is made possible by the fact that the magneto-resistive head 17 is much more sensitive than conventional ferrite core heads. As a surface area of the magnetic tape taken up by one magnetic signal decreases, the magnetic field emanating from the magnetic signal decreases also. Thus, for high density magnetic signals, a conventional ferrite core head is not sensitive enough to reliably detect the magnetic fields of the signals. In contrast, the magneto-resistive head 17 is sensitive enough to reliably detect the magnetic signal recorded on a portion of the magnetic tape with a width in the hundreds of .ANG.'s range.

As illustrated in FIG. 8C, the frontal surface 50 of the head chip 30 according to the preferred embodiment of the present invention can be furnished with a diamond-like carbon ("DLC") coating 60 to decrease friction with, and abrasion due to contact with, the magnetic tape. The DLC coating 60 lowers a frictional coefficient of the frontal surface 50 of the head chip 30. The resulting decrease in friction with the magnetic tape prevents the head chip 30 from abrading away, extending its lifespan. DLC is also attractive as a coating material because it is an insulator, and there is no danger that it might short the conducting plates 15, or affect in any way the magnetic field being read or recorded.

In addition, as illustrated in FIG. 9, the pair of FPCBs 32 for use in the head assembly according to the preferred embodiment of the present invention can each be provided with a notch 33 to facilitate the twisting thereof when the FPCBs are connected to the top surface of the head base 40. The notches 33 reduce a stress that is generated when the FPCBs 32 are twisted to connect them to the head base 40. This reduction in stress decreases the probability of the FPCBs 32 being damaged during a process of connecting them to the head base 40.

FIGS. 3A to 3BB are schematic cross sectional views setting forth a method for the manufacture of the head chip 30 for use in the head drum assembly according to the preferred embodiment of the present invention. The process of manufacturing the head chip 30 for use in the inventive head assembly begins with providing a first non-magnetic substrate wafer 11' made of a non-magnetic material, such as Al.sub.2 O.sub.3. Referring to FIGS. 3A and 3B, a first magnetic layer (not shown) composed of a permalloy is deposited on top of the first non-magnetic substrate wafer 11' thus giving rise to the first magnetic core 12. This first magnetic layer is deposited, for example, by means of a sputtering process to a depth of at least 10 .mu.m. Then, the first insulating layer 13 is deposited on top of the first magnetic core 12, for example, by a sputtering method, to a depth equivalent to the desired width of the magnetic gap 18, i.e. 0.15 .mu.m or less if a signal density larger than twice the conventional signal density is to be achieved.

Next, as shown in FIGS. 3C and 3D, a magneto-resistive layer 14' is formed on top of the first insulating layer 13 in three stages. First, a thin film of NiFe is deposited on top of the first insulating layer 13 to a depth of 500 nm. For this layer, a mix between 78% Ni 22% Fe and 85% Ni 15% Fe that minimizes magnetostriction should be chosen as a composition. Then, a thin film of Ti is deposited to a depth of 200 nm. Finally, a thin film of amorphous CoZrMo is deposited to a depth of 700 nm.

As shown in FIGS. 3E and 3F, the magneto-resistive layer 14' formed as described above is then patterned into a magneto-resistive core 14 through, for example, a photolithography method. Next, a conducting layer 15' is formed on top of the magneto-resistive core 14 and the first insulating layer 13 to a depth of 0.5 .mu.m as illustrated by FIGS. 3G and 3H. This procedure might be carried out by depositing Au using an evaporation method.

Then, the conducting layer 15' is patterned into the conducting plates 15. A possible method of carrying this step out is the photo-lithography method. FIGS. 3I and 3J present a result of this step. Subsequently, as shown in FIGS. 3K and 3L, the second insulating layer 16 is formed on top of the conducting plates 15, the magneto-resistive core 14, and the portions of the first insulating layer 13 not yet covered up, thus completing the magneto-resistive head 17. The second insulating layer 16 should be composed of a non-magnetic material such as Al.sub.2 O.sub.3 or SiO.sub.2.

Next, the thin film head 26 is added by first depositing a second magnetic layer 21' on top of the second insulating layer 16 to a depth of 8 .mu.m. The composition of the second magnetic layer 21' should be 80% Ni and 20% Fe. Then, as shown in FIGS. 3M and 3N the second magnetic layer 21' is patterned into the second magnetic core 21 through, for example, a photo-lithography method. The second magnetic core 21 and the second insulating layer 16 are in turn covered up by the third insulating layer 22, which, as illustrated in FIGS. 30 and 3P, is deposited thereon. The third insulating layer 22 should be composed of a non-magnetic material such as Al.sub.2 O.sub.3 or SiO.sub.2, and can be deposited through sputtering method.

For the next step, an Au layer is deposited through, for example, the evaporation method, on top of the third insulating layer 22 to form the conducting coil layer 23'. As shown in FIGS. 3Q and 3R, this conducting coil layer 23' is patterned into the conducting coil 23. One possible method of completing this step might be the photo-lithography method. Then, the third insulating layer 22 and the conducting coil 23 are covered up by depositing the fourth insulating layer 24 thereon, as illustrated in FIGS. 3S and 3T, by using, for example, a sputtering method.

Subsequent to this step, a rectangular portion of the fourth insulating layer 24 and the third insulating layer 22 are removed, thus exposing the rectangular strip of the second magnetic core 21, as shown in FIGS. 3U and 3V. Then, a third magnetic layer 25' composed of 80% Ni and 20% Fe is formed on top of the fourth insulating layer 24 while filling the rectangular portion of the third and the fourth insulating layer 22, 24 removed in the previous step, as illustrated by FIGS. 3W and 3X.

As shown in FIGS. 3Y and 3Z, the third magnetic core 25 is then patterned out of the third magnetic layer 25' through, for example, the photo-lithography method. Next, as shown in FIGS. 3AA and 3BB, the fourth insulating layer 24 and the third magnetic core 25 are covered up by the fifth insulating layer 27 deposited through, for example, the sputtering method. Then, after cutting the first non-magnetic substrate wafer 11' into slices, a posterior strip of the third, fourth and fifth insulating layers 22, 24, 27 are removed, thus completing the thin film head 26.

FIG. 4A illustrates the first non-magnetic substrate wafer 11', and the magneto-resistive head 17 and the thin film head 26 deposited thereon just prior to the removal of the posterior strip of the third, fourth, and fifth insulating layers 22, 24, 27. As shown in FIG. 4B, after cutting the first non-magnetic substrate wafer 11' and the layers deposited thereon into slices and removing the posterior strip of the thin film head 26, a second non-magnetic substrate block layer 31" is attached to the top surface of the thin film head 26, while leaving uncovered a posterior strip thereof. Next, each slice of the first non-magnetic substrate wafer 11' and the layers deposited thereon are cut into individual head chips 30. During a cutting process, each head chip 30 is given an azimuth inclination .THETA. by cutting it with an inclination. Then, the FPCBs 32 are attached to the magneto-resistive head 17 and the thin film head 26 as shown in FIG. 4C. The FPCBs are attached such that one FPCB is in contact with the conducting plates 15 of the magneto-resistive head 17, and the other is in contact with the conducting coil 23 of the thin film head 26.

FIGS. 6A to 6DD present a method for the manufacture of the head chip 30 for use in the head assembly in accordance with another preferred embodiment of the present invention, wherein the magneto-resistive head 17 and the thin film head 26 are formed on separate non-magnetic substrate blocks and combined to form the head chip 30.

FIGS. 6A to 6L illustrate the steps in the formation of the magneto-resistive head 17 on the first non-magnetic substrate wafer 11', which are basically identical to the steps in the formation of the magneto-resistive head 17 illustrated in FIGS. 3A to 3L. FIGS. 6M to 6DD show the steps in the formation of the thin film head 26, which are basically the same as the steps in the formation of the thin film head 26 illustrated in FIGS. 3M to 3BB, but for the fact that the thin film head 26 is formed on top of a second non-magnetic substrate block 31' instead of the magneto-resistive head 17. Note also that unlike the thin film head 26 shown in FIGS. 2A, 2B, 3AA, 3BB, the thin film head 26 shown in FIGS. 6CC and 6DD does not have a strip removed from its posterior portion.

FIG. 7A shows a first non-magnetic substrate wafer 11' and the magneto-resistive heads 17 formed thereon. FIG. 7B, in turn, shows the second non-magnetic substrate wafer 31' and the thin film heads 26 formed thereon. The first and second non-magnetic substrate wafer 11', 31' and the magneto-resistive head 17 and the thin film head 26 formed thereon are then cut into slices as shown in FIGS. 7C, 7D respectively. Next, portions of the magneto-resistive head 17 and the thin film head 26 are removed to provide a surface where the FPCBs 32 can be attached. Subsequently, as shown is FIG. 7E, the slices obtained by cutting the non-magnetic substrate wafers 11', 31' are combined to form slices including both the magneto-resistive head 17 and the thin film head 26. Following this, the slices obtained by combining the slices from the substrate wafer 11' and the substrate wafer 31' are cut up slantedly into individual head chips 30 providing them with the azimuth angle .THETA.. As shown in FIG. 7F, the FPCBs 32 are then affixed to the magneto-resistive heads 17 and the thin film heads 26. Finally, the head chip 30 thus obtained is then installed on the head base 40 while affixing the FPCBs 32 thereon as shown by FIG. 8A.

In the alternative, instead of furnishing the head gaps 18, 28 with the azimuth angle .THETA. by cutting each slice comprising the magneto-resistive head 17, the thin film head 26, and the substrate blocks 11, 31, slantedly, as set out in the above disclosed methods, the head base 40 of the head assembly may instead be prepared with a slanted surface with an angle of inclination corresponding to the azimuth angle .THETA., as disclosed in greater detail in a copending commonly owned application, U.S. Ser. No. 08/551,210, now U.S. Pat. No. 5,721,653, entitled "IMPROVED HEAD ASSEMBLY FOR USE IN A VIDEO CASSETTE RECORDER", which is incorporated herein by reference.

The head assembly for use in a VCR and the method for the manufacture thereof described above improve upon conventional ferrite core head assemblies by making possible the reproduction and the recording of high density magnetic signals on magnetic tapes. The head assembly described above utilizes the head chip 30 which, due to its greater sensitivity, can detect smaller magnetic fields than it is possible with conventional ferrite core head chips, and in addition is equipped with magnetic gaps that have much smaller widths than magnetic gaps included in conventional ferrite core head chips, thus allowing smaller signals to be recorded on, or reproduced from, magnetic tapes. This reduction in head gap width, in turn, is made possible by the manufacturing methods used to produce the inventive head assembly.

In addition, by coating the frontal surface 50 of the head chip 30 with the DLC coating 60, the head assembly according to the present invention extends the lifespan of its head chip 30 by reducing friction with the magnetic tape. Finally, the head assembly according to the present invention facilitates the attaching of the FPCBs 32 to the head base 40 by providing the former with the notches 33.

While the present invention has been shown and described with respect to certain preferred embodiments only, it should be clear to those skilled in the art that many changes and modifications may be made without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims

1. A method for the manufacture of a head assembly for use in a VCR, the method comprising the steps of:

providing a first non-magnetic substrate wafer;

forming a first magnetic core on top of the non-magnetic substrate wafer;

depositing a first insulating layer on top of the first magnetic core;

forming a magneto-resistive layer on top of the first insulating layer;

patterning the magneto-resistive layer into a magneto-resistive core;

depositing a conducting layer on top of the magneto-resistive core and the first insulating layer;

removing portions of the conducting layer to thereby form a pair of conducting plates;

forming a second insulating layer on top of the magneto-resistive core and the pair of conducting plates;

depositing a second magnetic layer on top of the second insulating layer;

patterning the second magnetic layer into a second magnetic core;

forming a third insulating layer on top of the second magnetic core and the second insulating layer;

depositing a conducting coil layer on top of the third insulating layer;

removing portions of the conducting coil layer to thereby form a conducting coil;

forming a fourth insulating layer on top of the third insulating layer and the conducting coil;

removing portions of the fourth insulating layer and the third insulating layer formed on top of the second magnetic core;

depositing a third magnetic layer on top of the fourth insulating layer while filling in the gaps left by the removed portions of the fourth insulating layer and the third insulating layer;

patterning the third magnetic layer into a third magnetic core;

depositing a fifth insulating layer on top of the third magnetic core and the fourth insulating layer;

cutting the first non-magnetic substrate wafer and the layers deposited thereon into a plurality of slices;

affixing a second non-magnetic substrate block layer on top of each slice;

cutting each slice into a plurality of head chips;

attaching a pair of flexible printed circuit boards ("FPCB") to each head chip; and

installing the head chips and the attached FPCBs onto a plurality of head bases.

2. A method for the manufacture of a head assembly for use in a VCR, the method comprising the steps of:

providing a first non-magnetic substrate wafer;

forming a first magnetic core on top of the non-magnetic substrate wafer;

depositing a first insulating layer on top of the first magnetic core;

forming a magneto-resistive layer on top of the first insulating layer;

patterning the magneto-resistive layer into a magneto-resistive core;

depositing a conducting layer on top of the magneto-resistive core and the first insulating layer;

removing portions of the conducting layer to thereby form a pair of conducting plates;

forming a second insulating layer on top of the magneto-resistive core and the pair of conducting plates;

providing a second non-magnetic substrate wafer;

forming a second magnetic layer on top of the second non-magnetic substrate wafer;

patterning the second magnetic layer into a second magnetic core;

depositing a third insulating layer on top of the second magnetic core and the second insulating layer;

forming a conducting coil layer on top of the third insulating layer;

removing portions of the conducting coil layer to thereby give rise to a conducting coil;

forming a fourth insulating layer on top of the third insulating layer and the conducting coil;

removing portions of the fourth insulating layer and the third insulating layer formed on top of the second magnetic core;

forming a third magnetic layer on top of the fourth insulating layer while filling in the gaps left by the removed portions of the fourth insulating layer and the third insulating layer;

patterning the third magnetic layer into a third magnetic core;

depositing a fifth insulating layer on top of the third magnetic core and the fourth insulating layer;

cutting the first non-magnetic substrate wafer and the layers deposited thereon into a plurality of slices;

cutting the second non-magnetic substrate wafer and the layers deposited thereon into a plurality of slices;

combining the slices with the magneto-resistive heads with the slices with the thin film heads to thereby form a plurality of slices containing thin film heads and magneto-resistive heads;

cutting each slice obtained by combining the slices with the magneto-resistive heads and the slices with the thin film heads into a plurality of head chips;

attaching a pair of flexible printed circuit boards ("FPCB") to each head chip; and

installing the head chips and the attached FPCBs onto a plurality of head bases.