JP2007071598A - Inductance measuring device of magnetic head and measuring method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve measurement accuracy by preventing a measurement error caused by a parasitic capacity of a probe pin, by improving a technology for measuring the inductance of a magnetic head by bringing a current application probe pin and a voltage measuring probe pin into contact with a pad of the magnetic head formed on a wafer. <P>SOLUTION: When taking a magnetic head 1 into consideration from among a plurality of magnetic heads 1A-1D, the current application probe pin 5a is extended to a pad 2a from its +Y side and brought into contact with the pad 2a, and the voltage measuring probe pin 6a is extended from the -Y side of the pad 2a and brought into contact with the pad 2a. Hereby, since the current application probe pin 5a and the voltage measuring probe pin 6a are not faced each other in the parallel state, a parasitic capacity is not generated between both probe pins. A pad 2b is put in the similar state, and the other magnetic heads are put in the similar state. Thus, the measurement error caused by a parasitic capacity is prevented, and the inductance measurement accuracy is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for measuring the inductance of a probe pin in contact with a pad of a magnetic head, and in particular, the inductance of a large number of magnetic heads formed on a wafer can be simultaneously measured with high accuracy. The measuring apparatus improved in this way, and the measuring method.

FIG. 3 is a view for explaining a conventional magnetic head, and FIG. 3A is a plan view schematically showing one magnetic head.
The magnetic head 1 includes one read element MR that performs a read operation and one write element IND that performs a write operation.
The read element MR has two pads 2a and 2b, and the write element IND has two pads 2c and 2d and a write coil 3. A ground terminal is indicated by a reference symbol G.
In FIG. 6A, one magnetic head 1 is drawn. When this is produced, a large number of magnetic heads 1 are arranged on the surface of the wafer 4 and formed at once as shown in FIG. Is done.

FIG. 4 is a perspective view schematically showing a state in which the inductance of one magnetic head 1 is measured.
For convenience of explanation, orthogonal three axes X, Y, and Z are assumed. The coordinate axes in the present invention are for convenience of explanation, and the coordinate axes can be converted. That is, the essential constituent requirements of the present invention are not limited.
In the accompanying drawings of the present application, the surface of the magnetic head is aligned with the XY plane, and the arrangement direction of a large number of pads is the X-axis direction.

As shown in FIG. 4, the inductance measurement operation is performed by bringing two probe pins, that is, current application probe pins and voltage measurement probe pins into contact with each other for each of a large number of pads.
In order to clarify the explanation, a reference numeral and a name are attached to each component member as shown in the figure.
A current application probe pin 5a and a voltage measurement probe pin 6a are provided for the pad 2a.
A voltage measurement probe pin 6b and a current application probe pin 5b are connected to the pad 2b.
A current application probe pin 5c and a voltage measurement probe pin 6c are connected to the pad 2c.
A voltage measurement probe pin 6d and a current application probe pin 5d are connected to the pad 2d.
Each is in contact conduction.
This schematic diagram of FIG. 4 represents the basic principle of the inductance measurement operation, and is applied mutatis mutandis throughout the present invention. However, since this figure shows the principle, it is applied with various modifications. The present invention, which will be described in detail later, is an improved arrangement of probe pins in inductance measurement.

The magnetic head is a very small member. In the example shown in FIG. 4, the long side is about 1.2 mm and the short side is about 0.3 mm.
As shown in FIG. 3B, a large number of such ultra-small members are formed on the surface of the wafer 4, so that the plurality of magnetic heads are connected to each other before separating the magnetic heads individually. In this state, the inductance is measured as described below. In the present invention, “a plurality of magnetic heads formed on a wafer” refers to magnetic heads connected in this manner.
FIG. 5 is a schematic plan view illustrating a state (conventional example) in which the inductances of four magnetic heads 1A, 1B, 1C, and 1D are simultaneously measured.

Each of the four magnetic heads 1A, 1B, 1C, and 1D is provided with two pads (the pads were previously described with reference to FIGS. 3 and 4). Therefore, 4 * 4 = 16 pads are provided on the four magnetic heads shown.
In order to simplify the description, two pads denoted by reference numerals 2a and 2b are considered as one unit. The whole of FIG. 5 is an arrangement of 8 units.
A current application probe pin 5a and a voltage measurement probe pin 6a are connected to the pad 2a.
A voltage measurement probe pin 6b and a current application probe pin 5b are connected to the pad 2b.
Each probe pin is extended in the −Y direction in parallel to the Y axis from the + Y side of the pad, and the tips of these probe pins are brought into contact with the pad.

Since the conventional example shown in FIG. 5 can measure four magnetic heads simultaneously, a highly efficient measurement operation is possible. Similarly, simultaneous measurement of six or eight is not impossible.
In addition, since the magnetic head is formed on the wafer and the measurement can be performed before the individual separation, the measurement operation can be performed with high efficiency.
As will be described in detail later, the present invention has been improved without impairing the advantages of the above-described conventional example that “a highly efficient measurement operation is possible”.
JP 2004-199796 A

In order to understand the problem to be solved by the present invention, the form of measurement will be considered. Not only the inductance measurement but also the physical quantity measurement generally includes laboratory measurement for academic research and measurement for inspection in the production process.
In laboratory measurements, maximum precision is sought without cost and effort.
In production inspection measurement, efficiency improvement and cost reduction are pursued on the assumption that the error is within an allowable range.
The inventors of the present invention compared the inductance value measured separately in the laboratory and the production inspection inductance measurement result according to the prior art shown in FIG. It was confirmed that it was unacceptably large.

The inductance measured as a result of laboratory inspection of the magnetic head of the conventional example shown in FIG. 4 was 8 nH, whereas the inductance measured by industrial inspection was 5.53 nH. Whether or not the difference 2.47 nH is within an allowable range cannot be generally stated. However, under the development conditions in which the present inventor has studied the inductance measurement of the magnetic head, the above-mentioned 2.47 nH (error rate 30) %) Was determined to be outside the acceptable range.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an improved measuring apparatus and an apparatus for measuring the inductance of a large number of magnetic heads formed on a wafer with high accuracy. It is to provide a measurement method. However, the improvement is based on the premise that the advantage of the conventional example (FIG. 5) that a large number of magnetic heads can be measured simultaneously with high efficiency will not be impaired, and that the weight, shape and manufacturing cost of the entire measuring device will not be increased. It is. .

In order to achieve the above object, the present inventors have sought the cause of excessive error in the conventional inductance measurement shown in FIG.
As a result, it was confirmed that the parasitic capacitance as shown in FIG. 5 was the cause of the error. Details are as follows.
Between the current application probe pin 5a and the voltage measurement probe pin 6b, a parasitic capacitance Ca is
Between the voltage measurement probe pin 6a and the current application probe pin 5b, the parasitic capacitance Cb is
Between the current application probe pin 5a and the voltage measurement probe pin 6a, a parasitic capacitance Cc is
Between the voltage measurement probe pin 6b and the current application probe pin 5b, a parasitic capacitance Cd is
Each exists. These four types of parasitic capacitances Ca, Cb, Cc, and Cd are the main causes of inductance measurement errors.

The present inventors have attempted to reduce the parasitic capacitance for the final purpose of reducing the inductance measurement error.
As a practical matter, it is impossible to change the dielectric constant of the material around the probe pin, and it is not easy to significantly reduce the thickness dimension of the probe pin.
Therefore, the inventors reduced the parasitic capacitances Ca, Cb, Cc, and Cd by increasing the distance between the probe pins.
However, it is not just “enlarge the distance between probe pins”.
Since it is possible to measure a large number of magnetic heads at the same time and to prevent a large number of probe pins from interfering with each other, "enlarging the distance between probe pins" is not just a design consideration, but a technology related to probe pin arrangement. This was achieved for the first time by fundamentally reforming the idea.

As a specific configuration based on the aforementioned principle (enlargement of the distance between the probe pins), the inventive device according to claim 1 (see FIG. 1),
An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set orthogonal two axes XY parallel to the wafer surface, align the arrangement direction of the pads with the X axis, and assume ± directionality with respect to the coordinate axes,
For one pad (for example, 2a), one probe pin (for example, 5a) parallel to the Y axis with the tip directed in the + Y direction, and one parallel to the Y axis with the tip directed in the -Y direction The probe pins (for example, 6a) are provided so that both probe pins face each other in the Y-axis direction (in the related art, the probe pins that are arranged in parallel and face each other in the X-axis direction) Was improved to oppose the Y axis in a straight line).

The configuration of the invention device according to claim 2 (see FIG. 2A),
An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
An orthogonal two-axis XY parallel to the wafer surface is set to align the pad arrangement direction with the X-axis, and the angle between the straight line passing through the coordinate origin and the Y-axis is ± θ,
One of the two probe pins (for example, 5a) to be brought into contact with the same pad (for example, 2a) is inclined in the + θ direction, and the other (for example, 6a) is inclined in the −θ direction. The arrangement of (5a, 6a) is generally radial (it can also be referred to as a C-shape).

The configuration of the invention device according to claim 3 is as follows (see FIG. 2B).
An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set the orthogonal 2-axis XY parallel to the wafer surface and the Z-axis perpendicular to the wafer surface, and align the arrangement direction of the pads with the X-axis,
One of the two probe pins (for example, 5a, 6a) to be brought into contact with the same pad (for example, 2a) (for example, 6a) is substantially parallel to the Y axis,
The other of the two probe pins (for example, 5a) is substantially in the Z-axis direction or an oblique direction (for example, 5a ') including a component in the Z-axis direction.

The configuration of the invention method according to claim 4 (see FIG. 1),
A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set two orthogonal axes XY parallel to the wafer surface, and align the arrangement direction of the pads with the X axis.
A current application probe pin (for example, 5a) is extended from the + Y side of the pad (for example, 2a), and the tip is brought into contact with the pad (for example, 2a).
A voltage measurement probe pin (for example, 6a) is extended from the -Y side of the pad (for example, 2a), and a tip thereof is brought into contact with the pad (for example, 2a) to reduce parasitic capacitance around the probe pin. To do.

The configuration of the inventive method according to claim 5 (see FIG. 2),
A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
An orthogonal two-axis XY parallel to the wafer surface is set so that the arrangement direction of the pads is aligned with the X-axis, and the angle formed by the straight line passing through the coordinate origin O and the Y-axis is ± θ. Assuming direction,
A current application probe pin (for example, 5a) is extended from the + θ side of the pad (for example, 2a) toward the pad, and the tip of the probe is brought into contact with the pad.
A voltage measuring probe pin (for example, 6a) is extended from the -θ side of the pad (for example, 2a) toward the pad, and the tip thereof is brought into contact with the pad so that the probe pin (in this case, 5a, 6a) It is characterized by reducing the parasitic capacitance.

The configuration of the inventive method according to claim 6 is as follows (see FIG. 3).
A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set the orthogonal two-axis XY parallel to the wafer surface and the Z-axis perpendicular to the wafer surface, and align the pad arrangement direction with the X-axis,
A voltage measurement probe pin (for example, 6a) is extended from the Y side of the pad (for example, 2a), and its tip is brought into contact with the pad.
The current application probe pin (for example, 5a) is extended from a location where the Z coordinate value is different from that of the pad (for example, 2a), and the tip thereof is brought into contact with the pad,
Alternatively, the parasitic capacitance around the probe pin is reduced by replacing the voltage measuring probe pin (for example, 6a) and the current application probe pin (for example, 5a), and bringing the respective tips into contact with the pads. And

When the inventive device of claim 1 is applied, the current application probe pin and the voltage measurement probe pin are located on the opposite sides of the pad, and the parasitic capacitance between them is so small that it can be regarded as almost zero. It is. Therefore, the inductance measurement error due to the parasitic capacitance can be completely prevented in practice.
Moreover, since all the probe pins are all arranged in the Y-axis direction, there is no possibility of causing interference between the probe pins, and the inductances of a large number of magnetic heads can be measured at the same time, and the efficiency of the measurement work is high. .

  When the invention device of claim 2 is applied, the two probe pins brought into contact with one pad are inclined in opposite directions with respect to the Y axis, and generally form a radial quotient shape. There is very little parasitic capacitance between the probe pins. For this reason, the inductance measurement error due to the parasitic capacitance is small enough to be ignored in practice.

When the invention apparatus according to claim 3 is applied, one of the two probe pins brought into contact with one pad is in the Y-axis direction and the other intersects the XY plane. There is very little parasitic capacitance between the probe pins. For this reason, the inductance measurement error due to the parasitic capacitance is reduced to such an extent that it can be ignored in practice.
In addition, since the arrangement of a large number of probe pins is not limited to the XY plane, but is arranged in a three-dimensional intersection, the probe pin density per space is low. For this reason, there is no possibility of causing interference between probe pins, and the expected effect of being able to cope with further miniaturization of a magnetic head expected in the near future is also valuable.

When the invention method of claim 4 is applied,
Since the current application probe pin and the voltage measurement probe pin which are brought into contact with the same pad are positioned on the opposite sides with respect to the pad, the parasitic capacitance between them is so small that it can be regarded as almost zero. Therefore, the inductance measurement error due to the parasitic capacitance can be completely prevented in practice.
In addition, since all the many probe pins are arranged in the Y-axis direction, there is no possibility of causing interference between the probe pins, and the inductances of many magnetic heads can be measured at the same time, and the efficiency of measurement work is high.

When the invention method of claim 5 is applied,
The two probe pins contacting one pad are tilted in opposite directions with respect to the axis, and generally form a radial quotient, so that the parasitic capacitance between the two probe pins is very small. For this reason, the inductance measurement error due to the parasitic capacitance is reduced to such an extent that it can be ignored in practice.

When the invention method of claim 6 is applied,
Since one of the two probe pins brought into contact with one pad has a posture in the Y-axis direction and the other crosses the XY plane, the parasitic capacitance between both probe pins is very small. For this reason, the inductance measurement error due to the parasitic capacitance is reduced to such an extent that it can be ignored in practice.
In addition, the arrangement of a large number of probe pins is not limited to the XY plane, and the large number of probe pins are arranged in a three-dimensional manner, so that the probe pin density per space is low. For this reason, there is no possibility that the probe pins will interfere with each other, and the expected effect of being able to cope with further miniaturization of the magnetic head expected in the near future is also valuable.

FIG. 1 is a schematic view corresponding to one embodiment of the apparatus of the present invention, which is an improvement of the above-described FIG. 5 (conventional measuring apparatus) by applying the inventive apparatus of claim 1.
The four magnetic heads 1A, 1B, 1C, 1D are formed on the surface of the wafer and are not yet separated.
Since each magnetic head has four pads 2a, 2b, 2c and 2d, a total of 4 × 4 = 16 pads are used for the measurement, and four magnetic heads will be described as described below. It is configured so that the inductance can be measured simultaneously.

As described in the principle of inductance measurement with reference to FIG. 4, one current application probe pin and one voltage measurement probe pin must be brought into contact with one pad. Therefore, 16 current application probe pins and 16 voltage measurement probe pins must be arranged for 4 magnetic heads (16 pads).
Compared to the conventional example shown in FIG. 5 described above, this embodiment (FIG. 1) is the same in terms of the number of magnetic heads, the number of pads, and the number of probe pins. What is different is the arrangement. In other words, an arrangement has been created in which harmful parasitic capacitance does not occur. This will be described in detail below.

Orthogonal coordinates XY along the surface of the magnetic head are set. For convenience of explanation, the directionality of the Y axis is assumed to be + and −. Since this is for convenience of explanation, + and-may be replaced. That is, the constituent requirements of the present invention are not substantially restricted.
In order to consider the configuration of the present embodiment, “two pads indicated by reference numerals 2a and 2b and four probe pins in contact with them” are regarded as one unit. This embodiment (FIG. 1) consists of eight units.

The pads 2a and 2b are arranged in the X-axis direction. Four probe pins are arranged parallel to the Y axis.
Of the four probe pins, two current application probe pins are arranged on the + Y side of the pad, and two voltage measurement probe pins are arranged on the -Y side of the pad. Details are as follows.
The current application probe pin 5a is extended in the −Y direction from the + Y side of the pad 2a, and the tip thereof is brought into contact with the pad 2a. Similarly, the current application probe pin 5b is extended in the −Y direction from the + Y side of the pad 2b, and the tip thereof is brought into contact with the pad 2b.
On the other hand, the voltage measurement probe pin 6a is extended in the + Y direction from the −Y side of the pad 2a, and the tip thereof is brought into contact with the pad 2a. Similarly, the voltage measurement probe pin 6b is extended in the + Y direction from the −Y side of the pad 2b, and the tip thereof is brought into contact with the pad 2b.

The above is the configuration of the unit including the pads 2a and 2b. Next, the configuration of the unit including the pads 2c and 2d is the same as described above. That is,
The current application probe pin 5c is extended in the −Y direction from the + Y side of the pad 2c, and the tip thereof is brought into contact with the pad 2c. Similarly, the current application probe pin 5d is extended in the −Y direction from the + Y side of the pad 2d, and the tip thereof is brought into contact with the pad 2d.
On the other hand, the voltage measurement probe pin 6c is extended in the + Y direction from the −Y side of the pad 2c, and the tip thereof is brought into contact with the pad 2c. Similarly, the voltage measurement probe pin 6d is extended in the + Y direction from the −Y side of the pad 2d, and the tip thereof is brought into contact with the pad 2d.

As described above, two sets of units are arranged for the magnetic head 1A, and the inductance of the magnetic head 1A can be measured.
If two sets of units are provided for the other magnetic heads 1B, 1C, 1D, and 1E, the inductances of the four magnetic heads can be measured as shown in FIG.
As can be easily understood from FIG. 1, since the current application probe pin 5a and the voltage measurement probe pin 6a are located on the opposite sides with respect to the pad 2a, the parasitic capacitance Cc between them is very small.

That is, as shown in FIG. 5 (conventional example), since the “current application probe pin 5a and the voltage measurement probe pin 6a are not opposed in parallel”, the capacitance formed is very small.
Therefore, the error that the parasitic capacitance has on the inductance measurement is so small that it can be ignored in practice.
In the present embodiment, the current application probe pin 5a and the current application probe pin 5b face each other in parallel, but the influence of the parasitic capacitance existing between them on the inductance measurement is so small that it can be ignored. There is no risk of other problems.

As is clear from the structure and function described above, the constituent requirement that the probe pin in this embodiment is “parallel to the Y axis” does not need to be geometrically strict. That is, it is sufficient if it is almost parallel.
In addition, as described in paragraph 0003 describing the background art, the coordinate axes in the present invention can mutually convert X, Y, and Z, and the directionality (+, −) of the coordinate axes can be interchanged. (This applies not only to FIG. 1 already described, but also to FIG. 2 described later).
When the configuration described above with reference to FIG. 1 is viewed as an apparatus, it corresponds to the invention of claim 1.
Further, when viewed as a method, this corresponds to the invention of claim 4.

FIG. 2A shows a different embodiment from the above. The orthogonal coordinate XY added to FIG. 2A is the same as the orthogonal coordinate in FIG. 1 described above, but in this figure, an auxiliary axis obtained by rotating the Y axis in the coordinate plane is further illustrated. Suppose.
The rotation direction of the auxiliary axis represented by a chain line passing through the coordinate origin 0 is defined as + θ, and the rotation direction of the auxiliary axis represented by a dotted line passing through the coordinate origin 0 is defined as −θ. This ± is also for convenience of explanation.

In FIG. 2A, the periphery of the pad 2a and the pad 2b provided in the magnetic head 1A is drawn in an enlarged manner. The same is true for other magnetic heads and pads (both not shown).
The four probe pins 5a to 6b are generally positioned on the + Y side as compared to the pad, as in the previous example (FIG. 1), but the probe pins in this embodiment are parallel to the Y axis. Not
Inclined in the + θ and −θ directions. However, the entire probe pins do not have to be inclined, and as long as the vicinity of the portion in contact with the pad is inclined with respect to the Y axis as shown in the figure.

The current application probe pin 5a to be brought into contact with the pad 2a is not parallel to the Y axis and is inclined in the + θ direction. That is, the current application probe pin 5a is extended from the + θ direction with respect to the pad 2a, and The tip is in contact with the pad 2a.
On the other hand, the voltage measurement probe pin 6a is inclined in the −θ direction. That is, the voltage measuring probe pin 6a is extended from the -θ direction with respect to the pad 2a, and the tip thereof is in contact with the pad 2a.
Further, with respect to the pad 2b, the voltage measuring probe pin 6b is extended from the + θ direction with respect to the pad 2b, and the tip thereof is in contact with the pad 2b.
The current application probe pin 5b is inclined in the -θ direction. That is, the current application probe pin 5b is extended from the −θ direction with respect to the pad 2b, and the tip thereof is in contact with the pad 2b.
In carrying out the present invention, the inclination angle in the −θ direction and the inclination angle in the + θ direction are not necessarily the same angle.

When the probe pins are arranged as in the present embodiment (FIG. 2A), the two probe pins brought into contact with one pad form a radial shape (C shape), and the average distance between them is growing. Therefore, the parasitic capacitance between these probe pins is reduced, and the inductance measurement error is reduced.
The configuration of FIG. 2A described above corresponds to claim 2 when viewed as a device invention, and corresponds to claim 5 when viewed as a method invention.

FIG. 2B is a schematic perspective view of an embodiment further different from the above, and similarly to FIG. 2A, the periphery of the pad 2a and the pad 2b provided in the magnetic head 1A is extracted. Enlarged and drawn. The same is true for other magnetic heads and pads (both not shown).
In the present embodiment, in addition to the orthogonal coordinate XY described above, a Z axis perpendicular to the surface of the wafer is added to set an orthogonal three axis XYZ.
The voltage measurement probe pin 6a is extended in the −Y direction from the + Y side to the pad 2a, and the tip is brought into contact with the pad 2a.
The current application probe pin 5a is extended in the −Z direction from the + Z side of the pad 2a, and its tip is brought into contact with the pad 2a. That is, in FIG. 2B, the current application probe pin 5a is projected downward from above the magnetic head 1A, and the tip thereof is brought into contact with the pad 2a.
Similarly, with respect to the pad 2b, the voltage measurement probe pin 6b is extended in the −Y direction from the + Y side, and the tip is brought into contact with the pad 2b.
The current application probe pin 5b is extended in the −Z direction from the + Z side of the pad 2b, and the tip thereof is brought into contact with the pad 2b.

When configured as shown in FIG. 2B described above, the current application probe pins and the voltage measurement probe pins, which are densely arranged in the vicinity of the XY plane (near the magnetic head surface) in the prior art, are converted into XYZ. The probe pin density per space (unit volume) is reduced.
Even in the latest technology, making the eight probe pins in contact with a magnetic head, which is a minute member of 1.2 mm × 0.3 mm, requires high-precision manufacturing technology. If the three-dimensional arrangement is avoided as in (), design and manufacture are facilitated in terms of dimensional accuracy, and the degree of freedom in design increases.
Furthermore, it is predicted that the miniaturization of the magnetic head will be further advanced with the technical progress of electronic equipment. Placing probe pins in three dimensions is valuable as a technology that can cope with the miniaturization of magnetic heads.

As a modification of the embodiment shown in FIG. 2 (B), the current application probe pin 5a can be inclined with respect to the Z axis as shown by a virtual line 5a 'without being parallel to the Z axis. Even if it comprises in this way, the same effect can be obtained about reducing parasitic capacitance and improving inductance measurement precision.
As described above, the configuration of inclining with respect to the Z-axis basically means that the arrangement of the probe pins has a Z-axis direction component.

As shown in FIG. 2B, there is no need to worry about whether the entire inductance measuring device becomes large and heavy by giving the probe pin a Z-axis direction component. The reason is as follows.
As previously described in FIG. 4 as an example of the actual size, the size of the magnetic head is as small as 1.2 mm × 0.3 mm, and eight probe pins are brought into contact with each other. Therefore, the average interval between the probe pins in the X-axis direction is about 40 to 100 microns. That is, in the prior art, a large number of probe pins are densely packed on the XY plane and are overcrowded in the X-axis direction. Even if such a probe pin arrangement form is improved and the arrangement has a Z-axis direction component, the overall shape and size of the inductance measuring apparatus is practically unchanged.
Further, even if the probe pin has a Z-axis direction component, the weight of the probe pin hardly changes. In addition, the number of probe pins does not change due to the application of the present invention.

  The configuration described above with reference to FIG. 2B corresponds to claim 3 when viewed as an apparatus invention, and corresponds to claim 6 when viewed as a method invention.

1 is a schematic plan view showing an embodiment of the present invention and corresponding to claims 1 and 4. (A) shows an embodiment different from the above, and is a schematic plan view corresponding to claim 2 and claim 5, and (B) shows a further different embodiment, and a pattern corresponding to claim 3 and claim 6. Perspective view 1A and 1B are schematic views of a magnetic head, and FIG. 2B is a partially broken plane illustrating a state in which a number of magnetic heads are formed on a wafer. Figure Illustration of the principle of measuring the inductance of a magnetic head FIG. 2 is a diagram illustrating a conventional inductance measurement technique and its problems, and is a schematic plan view illustrating a state in which the inductance of a magnetic head is measured, with a parasitic capacitance added thereto.

Explanation of symbols

  1A, 1B, 1C, 1D ... Magnetic head, 2a, 2b, 2c, 2d ... Pad, 3 ... Write coil, 4 ... Wafer, 5a, 5b, 5c, 5d Current application probe pin, 6a, 6b, 6c, 6d … Voltage measurement probe pin.

Claims (6)

An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set two orthogonal axes XY parallel to the wafer surface, and align the arrangement direction of the pads with the X axis.
For one pad, one probe pin with the tip directed in the + Y direction and parallel to the Y axis, and one probe pin with the tip directed in the −Y direction and parallel to the Y axis are provided. An inductance measuring apparatus for a magnetic head. An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
An orthogonal two-axis XY parallel to the wafer surface is set to align the pad arrangement direction with the X-axis, and the angle between the straight line passing through the coordinate origin and the Y-axis is ± θ,
One of the two probe pins contacting the same pad is inclined in the + θ direction and the other is inclined in the −θ direction, respectively, and the arrangement of the two probe pins is generally radial. , Magnetic head inductance measuring device. An apparatus for measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set the orthogonal 2-axis XY parallel to the wafer surface and the Z-axis perpendicular to the wafer surface, and align the arrangement direction of the pads with the X-axis,
One of the two probe pins that make contact with the same pad is almost parallel to the Y axis,
2. The magnetic head inductance measuring apparatus according to claim 1, wherein the other of the two probe pins is substantially in the Z-axis direction or a direction including a component in the Z-axis direction. A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set two orthogonal axes XY parallel to the wafer surface, and align the arrangement direction of the pads with the X axis.
Extend the current application probe pin from the + Y side of the pad and bring its tip into contact with the pad.
A method of measuring an inductance of a magnetic head, comprising: extending a voltage measuring probe pin from the -Y side of a pad and bringing a tip thereof into contact with the pad to reduce a parasitic capacitance around the probe pin. A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
An orthogonal two-axis XY parallel to the wafer surface is set to align the pad arrangement direction with the X-axis, and the angle between the straight line passing through the coordinate origin and the Y-axis is ± θ,
The current application probe pin is extended from the + θ side of the pad toward the pad, and the tip is brought into contact with the pad.
A method of measuring an inductance of a magnetic head, characterized in that a voltage measuring probe pin is extended from the -θ side of the pad toward the pad and the tip of the voltage measuring probe pin is brought into contact with the pad to reduce parasitic capacitance around the probe pin. . A method of measuring the inductance of a magnetic head by bringing a probe pin for applying a current and a probe pin for measuring a voltage into contact with each of a plurality of magnetic head pads formed on a wafer. In
Set the orthogonal 2-axis XY parallel to the wafer surface and the Z-axis perpendicular to the wafer surface, and align the arrangement direction of the pads with the X-axis,
Extend either the current application probe pin or the voltage measurement probe pin from the Y side of the pad, and make the tip contact with the pad.
The other of the current application probe pin or the voltage measurement probe pin is extended from a position away from the pad in the Z-axis direction, and the tip thereof is brought into contact with the pad to reduce the parasitic capacitance around the probe pin. , Magnetic head inductance measurement method.

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