Method for manufacturing a circuit board capable of protecting an MR magnetic head therein against electrostatic breakdown and a method for manufacturing a magnetic head using the same

The invention provides a magnetic head capable of positively preventing electrostatic breakdown of an MR magnetic head device, and a method of manufacturing the magnetic head. A circuit board comprises at least a pair of leads for constructing a circuit, lands connected respectively to the leads, and solder bumps formed respectively on the lands. The solder bumps are arranged in an adjacent relationship and, when the solder bumps are crushed, peripheral portions of the solder bumps are pressed or spread so as to overlap with each other. The magnetic head includes the circuit board.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a circuit board, and a magnetic head incorporating the circuit board. More particularly, the present invention relates to a circuit board capable of protecting an MR magnetic head device, which incorporates the circuit board, against electrostatic breakdown.

2. Description of the Related Art

An example of a conventional magnetic head201for use in a computer hard disk is shown in FIG.17. The magnetic head201generally comprises a slider203, a load beam202, and a circuit board204. The slider203is attached to a fore end202aof the load beam202through a flexure, and a base plate209is attached to an opposite end202bof the load beam202. The circuit board204is attached to the base plate209.

The slider203includes an MR magnetic head device208for reproducing magnetically recorded data, and an inductive head device (not shown) for recording data to be magnetically recorded. From each of these head devices, two lead lines are extended to transmit and receive a reproduced signal and a recording signal to and from the outside of the magnetic head. These four lead lines205a,205b,206a,206bare connected to the circuit board204at the side of the base plate209where it is attached to the opposite end202bof the load beam202.

The circuit board204is formed of a flexible printed board, and includes four leads215a,215b,216a,216bconnected respectively to the lead lines extended from the head devices (i.e.,205a,205b,206a,206b). Mounting terminals215c,215d,216c,216dare provided respectively midway on the leads215a,215b,216a,216b. Inspection terminals215e,215f,216e,216fare provided respectively at ends of the leads215a,215b,216a,216b.

The leads215a,215b, that are connected to the lead lines205a,205bof the MR magnetic head device208, include lands223,224provided between the mounting terminals215c,215dand the inspection terminals215e,215f, respectively.

In a conventional magnetic head of this type, the circuit including the MR magnetic head device208is typically constructed as a closed circuit by attaching a shunt clip or forming a bonding wire between the lands223,224so as to short the lands223,224together. This is done to prevent electrostatic breakdown of the MR magnetic head device208during a period from manufacture of the magnetic head to assembly thereof into a hard disk drive.

This may result in a number of problems. For example, when the lands223,224are shorted together by using a clip, there is a risk that the clip may slip off as result of vibration during transport of the magnetic head. As a result, the MR magnetic head device208may suffer electrostatic breakdown.

Also, shorting the lands223,224together by wire bonding requires that a wire-bonding step be included in the manufacturing process of the magnetic head, thereby resulting in an increased production cost of the magnetic head.

In view of the state of the art set forth above, an object of the present invention is to provide a magnetic head capable of positively preventing electrostatic breakdown of an MR magnetic head device, and a method of manufacturing the magnetic head, that overcomes the above-identified problems.

SUMMARY OF THE INVENTION

The present invention is directed to a circuit board comprising at least a pair of leads for constructing a circuit, lands connected respectively to the pair of leads, and solder bumps formed respectively on the lands, wherein the solder bumps are arranged in an adjacent relationship. The solder bumps are subsequently crushed, causing peripheral portions of the solder bumps to spread and overlap with each other.

The present invention is also directed to a circuit board comprising at least a pair of leads for constructing a circuit, lands formed for connection respectively to the pair of leads, and a solder bridge for electrically interconnecting the lands, wherein the solder bridge is formed by peripheral portions of the solder bumps formed on the lands so that portions of the solder bumps overlap with each other. Preferably, the solder bridge is formed by crushing the solder bumps formed on the lands to an extent that crushed peripheral portions of the solder bumps are overlapped with each other.

Consequently, the leads constructing the circuit on the circuit board can be easily shorted together by crushing the solder bumps, and the circuit can be formed into a closed circuit.

Moreover, since the solder bridge is formed by the peripheral portions of the solder bumps which are integrally overlapped with each other, the contact area between the solder bumps is increased and the leads can be positively shorted between them.

Further, the present invention is directed to a circuit shorting method for a circuit board comprising at least a pair of leads for constructing a circuit, lands connected respectively to the pair of leads, and solder bumps formed on the lands and positioned adjacent to each other. The method comprises the steps of crushing one of the solder bumps such that a peripheral portion of the one solder bump is pressed to spread outward in a radial direction to approach the other solder bump; and then crushing the other solder bump such that a peripheral portion of the other solder bump is pressed to spread outward in a radial direction to contact with the peripheral portion of the one solder bump, whereby the pair of leads are shorted.

With this circuit shorting method, two solder bumps are contacted with each other by crushing the solder bumps one by one. Therefore, the solder bumps can be each positively crushed to make the leads shorted between them, and the circuit can be positively formed into a closed circuit.

In the above circuit shorting method, the step of crushing the other solder bump is preferably performed until a part of the peripheral portion of the other solder bump overlaps the peripheral portion of the one solder bump.

One feature of this circuit shorting method is that the pair of solder bumps are contacted with each other in an overlapping relation. Thus, the solder bumps are unlikely to be separated, even when the circuit board is bent or flexed. Further, a contact area between the solder bumps is increased and the pair of leads can be positively shorted between them.

In the above circuit shorting method, the solder bumps are preferably each crushed under heating. Heating of the solder bumps causes them to soften, thereby reducing the load required for crushing the solder bumps, and the solder bumps can be positively crushed without damaging the circuit board itself.

In the above circuit shorting method, the pair of solder bumps may be crushed simultaneously under heating. Crushing the solder bumps simultaneously, while being softened under heating, reduces the load required for crushing the solder bumps, and the pair of solder bumps can be positively contacted with each other even when they are crushed simultaneously. Additionally, damage of the circuit board itself can be avoided.

In the above circuit shorting method, the solder bumps are preferably each crushed under heating and rubbing. By heating and rubbing the solder bumps, each solder bump is caused to spread in the planar direction of the circuit board while being crushed. This causes the solder bumps to be more positively contacted with each other.

The present invention is directed to a magnetic head in which a slider including an MR magnetic head device is attached to a fore end of a load beam, a circuit board is attached to an opposite end of the load beam, and a pair of lead lines extended from the MR magnetic head device are connected to the circuit board. The circuit board comprises at least a pair of leads connected respectively to the lead lines and constructing a circuit including the MR magnetic head device in cooperation with the lead lines, lands connected respectively to the leads, and solder bumps formed respectively on the lands. The solder bumps are arranged in an adjacent relationship and, when the solder bumps are crushed, peripheral portions of the solder bumps are pressed to spread and overlap with each other.

The present invention is also directed to a magnetic head in which a slider including an MR magnetic head device is attached to a fore end of a load beam, a circuit board is attached to an opposite end of the load beam, and a pair of lead lines extended from the MR magnetic head device are connected to the circuit board. The circuit board comprises at least a pair of leads connected respectively to the lead lines and constructing a circuit including the MR magnetic head device in cooperation with the lead lines, lands connected respectively to the leads, and a solder bridge for electrically interconnecting the lands. The solder bridge is formed by peripheral portions of the solder bumps formed respectively on the leads and overlapped with each other. The solder bridge is preferably formed by crushing the solder bumps formed on the lands to an extent that crushed peripheral portions of the solder bumps are overlapped with each other.

With respect to the MR magnetic head device, a circuit is constructed with the lead lines extended from the head device and the pair of leads connected to the lead lines. The circuit can be easily formed into a closed circuit by crushing the solder bumps so that the pair of leads are shorted between them. As a result, the MR magnetic head device can be protected against electrostatic breakdown.

The present invention is directed to a method of manufacturing a magnetic head in which a slider including an MR magnetic head device is attached to a fore end of a load beam and a circuit board is attached to an opposite end of the load beam. The circuit board comprises at least a pair of leads connected to the MR magnetic head device, lands connected respectively to the pair of leads, and solder bumps formed respectively on the lands and positioned adjacent to each other. The method comprises the steps of crushing one of the solder bumps such that a peripheral portion of the one solder bump is spread outward in a radial direction to approach the other solder bump; and then crushing the other solder bump such that a peripheral portion of the other solder bump is likewise spread outward in a radial direction to contact with the peripheral portion of the one solder bump, whereby the pair of leads are shorted.

With this method of manufacturing a magnetic head, a circuit is constructed by the MR magnetic head device, the lead lines extended from the head device and the pair of leads connected to the lead lines. The circuit is formed into a closed circuit by crushing the solder bumps so that the pair of leads are shorted between them. Therefore, the MR magnetic head device can be protected against electrostatic breakdown.

In the above method of manufacturing a magnetic head, the step of crushing the other solder bump is preferably performed until a part of the peripheral portion of the other solder bump overlaps the peripheral portion of the one solder bump. Since the pair of solder bumps are contacted with each other in an overlapping relationship, the contact area between the solder bumps is increased and the pair of leads can be more positively shorted together, whereby the circuit including the MR magnetic head device can be formed into a closed circuit.

In the above described method of manufacturing a magnetic head, the solder bumps are each preferably crushed under heating. Heating softens the solder bumps, thereby reducing the load required for crushing the solder bumps, and the solder bumps can be crushed without damaging the circuit board itself.

In the above described method of manufacturing a magnetic head, the pair of solder bumps may be crushed simultaneously under heating. Crushing the solder bumps simultaneously while they are being softened under heating, reduces the load required for crushing the solder bumps, and the pair of solder bumps can be positively contacted with each other even when they are crushed simultaneously. Damage of the circuit board can consequently be avoided.

In the above described method of manufacturing a magnetic head, the solder bumps are each preferably crushed under heating and rubbing. By heating and rubbing the solder bumps as they are each crushed, each solder bump is spread in the planar direction of the circuit board while being crushed, which causes the solder bumps to be more positively contacted with each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows a magnetic head1according to the present invention. The magnetic head1mainly comprises a load beam2, a slider3attached to a fore end2aof the load beam2, and a circuit board4of the present invention attached to a base plate9. The base plate9is attached to a base (opposite) end2bof the load beam2.

The slider3includes an MR magnetic head device8serving as a reproducing head and an inductive head device (not shown) serving as a recording head, these head devices being provided on one end surface of the slider3.

One pair of lead lines5a,5bare extended from the MR magnetic head device8, and another pair of lead lines6a,6bare extended from the inductive head device.

The lead lines5a,5b,6a,6bare collected together by a flexible printed circuit (FPC)7on the upper surface of the load beam2. The FPC board7extends to the base plate9(attached to the opposite end2bof the load beam2).

The circuit board4is connected to the FPC board7through connection terminals17a,17b,18a,18b. The circuit board4is attached to the base plate9in an overlapped relationship to an end portion of the FPC board7.

The circuit board4of the present invention comprises, as shown inFIGS. 1to3, a substrate21and an insulating layer22formed over the substrate21. Four leads15a,15b,16a,16bare formed on the substrate21and are covered by the insulating layer22. Also, as shown inFIG. 1, the leads15a,15b,16a,16bare connected to the connection terminals17a,17b,18a,18b, respectively.

At the juncture (i.e., overlapped portion) between the circuit board4and the FPC board7, the connection terminals17a,17b,18a,18bof the circuit board4are connected respectively to four connection terminals (not shown) of the FPC board7.

As set forth in the above-described arrangement, the lead15ais connected to the lead line5athrough the connection terminal17a, and the lead15bis connected to the lead line5bthrough the connection terminal17b. Similarly, the lead16ais connected to the lead line6athrough the connection terminal18a, and the lead16bis connected to the lead line6bthrough the connection terminal18b.

Thus, the MR magnetic head device8, the lead lines5a,5band the leads15a,15bcooperatively construct or form a circuit.

Lands23,24are formed on the leads15a,15b(which forms the circuit including the MR magnetic head device8) between the mounting terminals15c,15dand the inspection terminals15e,15f, respectively, as shown inFIGS. 2 and 3. Solder bumps25,26, being substantially circular in plan view, are formed on the lands23,24, respectively. The lands23,24are formed as conductors positioned on the leads15a,15b, and projecting through the insulating layer22. The solder bumps25,26are formed respectively on the lands23,24and are electrically connected to the leads15a,15b.

In the preferred embodiment, the solder bumps25,26are formed from a solder made of, e.g., an SnPb alloy, and has a melting point preferably in the range of about 180° C.-185° C., taking into account that the solder bump is required to be easily crushed.

The solder bumps25,26are preferably arranged adjacent to each other and with a distance left between them that, when crushed, their peripheral portions25a,26aare spread outward in the radial direction to allow interconnection between the solder bumps25and26. More specifically, assuming that the solder bumps25,26each have a diameter of 0.29-0.34 mm, the center-to-center distance between the solder bumps25and26is preferably in the range of 0.39-0.41 mm. If the center-to-center distance is less than 0.39 mm, there is a risk that the solder bumps25,26may contact with each other when they are formed. Conversely, if the center-to-center distance is more than 0.41 mm, there is a risk that the solder bumps25,26may not contact with each other even after they are crushed.

FIGS. 4 and 5show the solder bumps25,26of the circuit board4after being crushed according to the present invention. When the solder bumps25,26are crushed, the peripheral portions25a,26aof the solder bumps25,26are caused to spread into an integrally overlapped relationship, thereby forming a solder bridge125. The solder bridge125electrically connects the lands23,24to each other for the purpose of shorting the leads15a,15btogether so that the circuit including the MR magnetic head device8is formed into a closed circuit.

A method of manufacturing the magnetic head of the present invention will now be described with reference to the drawings.

First, the slider3, including the MR magnetic head device8and the inductive head device (not shown), is attached to the fore end2aof the load beam2. The lead lines5a,5b,6a,6bare extended from the MR magnetic head device8and the inductive head device up to the base end2bof the load beam2through the FPC board7.

Then, the circuit board4is attached to the base end2bof the load beam2. At this time, the lead lines5a,5b,6a,6bare connected to the leads15a,15b,16a,16b, respectively, of the circuit board4through the connection terminals17a,17b,18a,18b. Accordingly, the MR magnetic head device8, the lead lines5a,5band the leads15a,15bare interconnected to form or construct a circuit.

Then, as shown inFIG. 6, a pressing tip30is prepared and pressed against the first solder bump25, whereupon the solder bump25is crushed as shown in FIG.7. As a result of this crushing, the peripheral portion25aof the solder bump25is pressed or spread outward in the radial direction so as to approach the other or second solder bump26.

Then, as shown inFIG. 8, the pressing tip30is pressed against the other or second solder bump26, whereupon the solder bump26is crushed. The peripheral portion26aof the solder bump26is thereby pressed or spread outward in the radial direction until the peripheral portion26aoverlaps the peripheral portion25aof the first solder bump25.

When the solder bumps25,26contact with each other, the leads15a,15bare shorted together or between them and the circuit including the MR magnetic head device8is formed into a closed circuit.

An alternative method for crushing the solder bumps25,26is shown inFIGS. 9-11. Instead of the pressing tip30(as described above), a heater tip33comprising a heat-resistant resin film31and a heater32attached to the film31is utilized. The heater tip33is pressed against the first solder bump25while heating the same, whereupon the solder bump25is crushed as shown in FIG.10. As a result of the crushing, the peripheral portion25aof the solder bump25is pressed or spread outward in the radial direction so as to approach the other or second solder bump26.

Then, as shown inFIG. 11, the heater tip33is pressed against the other or second solder bump26while heating the same, whereupon the solder bump26is crushed. The peripheral portion26aof the solder bump26is thereby pressed or spread outward in the radial direction until the peripheral portion26aoverlaps the peripheral portion25aof the first solder bump25.

As the solder bumps25,26contact each other, the leads15a,15bare shorted together or between them, and the circuit including the MR magnetic head device8is formed into a closed circuit.

In the case of crushing the solder bumps25,26by the heater tip33, it is preferable that the heating temperature of the solder bumps25,26be set to 170-210° C., and more preferably 175-185° C. The preferred heating time is 1.5-2.5 seconds, and more preferably 1.5-2.0 seconds.

If the heating temperature is lower than 170° C., then the solder may not be sufficiently softened, thereby preventing the solder bumps25,26from-contacting with each other, or that a too large of a load must be applied to crush the solder bumps25,26, which can cause the circuit board4to be damaged. If the heating temperature is higher than 210° C., then there is a risk that the solder bumps25,26are completely melted into a liquid state, and when crushed, parts of the solder may scatter around the solder bumps25,26upon collapse of the bump shapes.

Further, if the heating time is shorter than 1.5 seconds, there is a risk that the solder will not be sufficiently softened to permit the solder bumps25,26to contact with each other upon crushing. If the heating time is longer than 2.5 seconds, then there is a risk that the solder bumps25,26will completely melted into a liquid state, and when crushed, parts of the solder may scatter around the solder bumps25,26upon collapse of the bump shapes.

Another alternative method for crushing the solder bumps25,26is shown inFIGS. 12-13. A pressing tip35that is larger than the pressing tip30described above is utilized in conjunction with a heater34. The heater34is held in contact with the underside of the circuit board4to heat the solder bumps25,26. The pressing tip35is positioned above the circuit board4. Then, as shown inFIG. 13, both the solder bumps25,26are crushed simultaneously by the pressing tip35while they are heated from below with the heater34.

In this case, the peripheral portion25aof one solder bump25and the peripheral portion26aof the other solder bump26are simultaneously pressed or spread outward in the radial direction so as to approach and contact with each other. As the solder bumps25,26contact with each other, the leads15a,15bare shorted together or between them and the circuit including the MR magnetic head device8is formed into a closed circuit.

When crushing the solder bumps25,26by the larger pressing tip35and the heater34, the heating temperature and the heating time are preferably set in accordance with the above-described methods.

Moreover, when crushing the solder bumps25,26by any of the above-described methods (i.e., with the pressing tip30, the heater tip33, or the combination of the pressing tip35and the heater34, as shown inFIGS. 6to13), the solder bumps25,26are preferably crushed while the tips30,33, or35are moved in a rubbing fashion with respect to the solder bumps in the planar direction of the circuit board4. This rubbing improves or increases the spreading of the solder bumps25,26in the planar direction of the circuit board4during the step of crushing, thereby increasing the positive contacted between the solder bumps25,26.

With the magnetic head1described above, the MR magnetic head device8, the lead lines5a,5band the leads15a,15bcooperatively construct a circuit, and one pair of the solder bumps25,26connected to the leads15a,15bare crushed successively or simultaneously so as to contact with each other. The leads15a,15bare thereby shorted between them to make the constructed circuit become a closed circuit. As a result, the MR magnetic head device8can be protected against electrostatic breakdown.

With the above-described method of manufacturing the magnetic head1, the circuit including the MR magnetic head device8can be easily formed into a closed circuit by merely crushing the solder bumps25,26.

Also, with the above-described method of manufacturing the magnetic head1, the solder is softened by heating when the solder bumps25,26are crushed. Therefore, the load required for crushing the solder bumps25,26is reduced and the solder bumps25,26can be positively crushed without damaging the circuit board4.

Further, since the solder bumps25,26are crushed to an extent that a part of the peripheral portion26aof the other solder bump26overlaps the peripheral portion25aof one solder bump25, the contact area between the solder bumps25,26is increased and one pair of the leads can be more positively or securely shorted together or between them. As a result, the circuit including the MR magnetic head device8can be formed into a closed circuit. Since the peripheral portions25a,26aare overlapped with each other, the solder bumps25,26are avoided from separating off, for example, even when the circuit board4is bent.

Furthermore, with the above-described method of manufacturing the magnetic head1by crushing one pair of the solder bumps25,26while being heated, the load required for crushing the solder bumps25,26is reduced and the solder bumps25,26can be positively contacted with each other even though both the solder bumps are crushed at the same time, without damaging the circuit board4when the solder bumps are crushed.

In addition, with the above-described method of manufacturing the magnetic head1by crushing the solder bumps25,26in a rubbing fashion, the solder bumps25,26are pressed or spread in the planar direction of the circuit board4while being crushed and they can be more positively contacted with each other.

EXPERIMENTAL EXAMPLE 1

A land was formed on a circuit board, and a substantially semispherical solder bump having a diameter of 0.32 mm (320 μm) and a maximum height of 28 μm was formed on the land.

Further, on another circuit board, a substantially semispherical solder bump having a diameter of 0.26 mm (260 μm) and a maximum height of 25 μm was formed in a similar manner to the above. The solder used was made of an SnPb alloy and had the melting point of 183° C.

These solder bumps were each crushed by applying a load of 5-15 kgf, and changes in the bump diameter were measured. Measured results are shown inFIGS. 14 and 15.

As seen fromFIG. 14, the diameter of the solder bump having a diameter of 320 μm was changed to 450-490 μm after the crushing.

Also, as seen fromFIG. 15, the diameter of the solder bump having a diameter of 260 μm was changed to 370-430 μm after the crushing.

It is thus understood that, when the solder bump is crushed, the bump diameter is increased and a peripheral portion of the solder bump is pressed or spread outward in the radial direction.

EXPERIMENTAL EXAMPLE 2

Next, a circuit board including one pair of solder bumps, as shown inFIGS. 1to3, was fabricated. The solder bumps each had a diameter of 0.32 mm and the center-to-center distance between the solder bumps was 0.4 mm. The solder used was made of an SnPb alloy and had a melting point of 183° C.

First, one solder bump was crushed by heating the solder bump up to 220-260° C. for 1.0-2.5 seconds, under a load of 8 kgf with a heater tip, while the heater tip was moved in rubbing fashion in the planar direction of the circuit board. The other solder bump was then crushed in a similar manner.

Continuity between both the solder bumps was subsequently checked. Checked results are listed in Table 1 and shown schematically inFIGS. 16a-d.FIGS. 16a-dshows the solder bumps in successive states when crushed while being heated to a temperature of 250° C.

As seen from Table 1 andFIG. 16a, when the heating time is 1.0 second at the heating temperature in the range of 170-250° C., the solder bumps are insufficiently crushed and they do not contact with each other. Thus, no electrical conduction is established between the solder bumps.

As seen fromFIG. 16d,the heating temperature is higher than 210° C. and the heating time is longer than 2.5 seconds, the solder is excessively melted and a part of the solder is scattered around the solder bumps.

From the above results, it is understood that in order to crush and contact one pair of the solder bumps each having the diameter of 0.32 mm with the center-to-center distance of 0.4 mm, the solder bumps are preferably crushed while being heated to 170-210° C. for 1.5-2.0 seconds (seeFIGS. 16b-c).

As fully described above, the circuit board according to the present invention comprises at least a pair of leads and a pair of solder bumps. The solder bumps are arranged in an adjacent relationship and, when the solder bumps are crushed, peripheral portions of the solder bumps are overlapped with each other. Therefore, the leads constructing a circuit can be easily shorted together or between them by merely crushing the solder bumps, and the circuit can be formed into a closed circuit.

Also, the circuit board according to the present invention comprises a solder bridge for electrically interconnecting lands connected to the leads, the solder bridge being formed by the peripheral portions of the solder bumps formed on the lands, which are integrally overlapped with each other. Therefore, the contact area between the solder bumps is increased and the leads can be more positively shorted between them.

In addition, since the peripheral portions of the solder bumps are overlapped with each other, separation of the solder bumps is avoided, for example, even when the circuit board is bent. Therefore, the shorted state between the leads established by the solder bridge is maintained and reliability of the circuit board can be increased.

The circuit shorting method according to the present invention comprises the steps of crushing one of the solder bumps such that a peripheral portion of the one solder bump is pressed or spread outward in the radial direction to approach the other solder bump; and then crushing the other solder bump such that a peripheral portion of the other solder bump is pressed or spread outward in the radial direction to contact with the peripheral portion of the first solder bump, whereby the pair of leads are shorted. As a result, the circuit can be positively formed into a closed circuit.

Also, in the circuit shorting method according to the present invention, the step of crushing the other solder bump is performed until a part of the peripheral portion of the other solder bump overlaps the peripheral portion of the first solder bump. Therefore, a contact area between the solder bumps is increased and the leads can be positively shorted between them.

Further, in the circuit shorting method according to the present invention, the solder bumps are crushed while being softened under heating. Therefore, the load required for crushing the solder bumps is reduced and the solder bumps can be positively crushed without damaging the circuit board itself

Moreover, in the circuit shorting method according to the present invention, the solder bumps are crushed simultaneously while being softened under heating. Therefore, the load required for crushing the solder bumps is reduced and the solder bumps can be positively contacted with each other even when they are crushed simultaneously. Damage of the circuit board is therefore avoided at the time of crushing the solder bumps.

Additionally, in the circuit shorting method according to the present invention, the solder bumps are each crushed under heating and rubbing. Therefore, each solder bump is pressed or spread in the planar direction of the circuit board while being crushed, and the solder bumps can be more positively contacted, with each other.

In the magnetic head according to the present invention, a slider including an MR magnetic head device is attached to a fore end of a load beam, the above-mentioned circuit board is attached to an opposite end of the load beam, and a pair of lead lines extended from the MR magnetic head device are connected to the circuit board. The MR magnetic head device, the lead lines and the leads cooperate to construct or form a circuit. A pair of solder bumps connected to the leads are then crushed successively to be contacted with each other, whereby the leads are shorted together or between them and the circuit is formed into a closed circuit. As a result, the MR magnetic head device can be protected against electrostatic breakdown.

Also, the magnetic head according to the present invention includes a circuit board which comprises at least a solder bridge for electrically interconnecting lands connected to the leads, the solder bridge being formed by peripheral portions of the solder bumps formed respectively on the leads and overlapped with each other. Therefore, the contact area between the solder bumps is increased and the leads can be positively shorted together or between them so that the circuit including the MR magnetic head device is formed into a closed circuit.

In addition, since the peripheral portions of the solder bumps are overlapped with each other, separation of the solder bumps is avoided, for example, even when the circuit board is bent. Therefore, the shorted state between the leads established by the solder bridge is maintained to prevent electrostatic breakdown of the MR magnetic head device, and reliability of the circuit board can be increased.

Furthermore, with the method of manufacturing a magnetic head according to the present invention, the circuit including the MR magnetic head device can be easily formed into a closed circuit by merely crushing the solder bumps, and the MR magnetic head device can be protected against electrostatic breakdown.