JP2003069111A - Sensitivity evaluation device of magnetic resistance element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensitivity evaluation device of a magnetic resistance element which is excellent in possibility of highly accurate evaluation of sensitivity of a magnetic resistance element when sensitivity property of a magnetic resistance element is evaluated highly precisely. SOLUTION: A sensitivity evaluation device of a magnetic resistance element has an electromagnet unit 42 with two electromagnets. A pair of magnetic poles of each electromagnet are formed at a tip of a yoke 56 extending from a pair of cores of the electromagnet, and are positioned at a wafer table 12 side, whereon a wafer W is mounted, from an outer circumference of a solenoid of an electromagnet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaluation device for evaluating the sensitivity characteristic of a magnetoresistive element formed by being integrated on a wafer made of, for example, a semiconductor.

[0002]

2. Description of the Related Art This type of magnetoresistive element changes its electrical resistance depending on the transverse direction of an external magnetic field with respect to the internal magnetization direction. Therefore, by making the internal magnetization direction correspond to binary information, Random access memory (MRAM)
Is expected to be applied as a single memory cell. This type of MRAM can exhibit superior performance to internal memory such as so-called DRAM and external memory such as a hard disk, and MRAM has been actively developed in recent years.

A TMR element utilizing a spin-dependent tunnel effect (TMR effect) is used for this type of magnetoresistive element.
The element mainly has a three-layer structure of a ferromagnetic layer, an insulating layer and a ferromagnetic layer. Since the TMR elements that compose one memory cell of the MRAM are integrated and formed on the wafer made of semiconductor, the individual TMR elements are inspected, that is, the sensitivity characteristics are evaluated by forming the TMR elements on the wafer. M of the stage
It is preferable to implement this during the manufacturing of the RAM.
Defective TMR elements can be eliminated early and the yield of MRAM can be improved.

An example of the above-mentioned TMR element sensitive characteristic evaluation device is disclosed in Japanese Patent Laid-Open No. 9-283578, and this known evaluation device is formed between magnetic poles by a pair of solenoids. It only specifies the placement of the probe that extracts the output from the TMR element with respect to the magnetic field.

[0005]

Therefore, in the known evaluation apparatus, an X having a table on which a wafer is placed is used.
The relationship between the YZ stage and the solenoid is not concrete and its feasibility is poor. That is, in order to perform the sensitive characteristic evaluation of the TMR element with high accuracy,
It is necessary to form a uniform magnetic field across the TMR element.To this end, a pair of magnetic poles must be horizontally opposed to each other directly above the wafer, and a large magnetic gap between these magnetic poles must be secured. I have to.

However, with the expansion of the magnetic gap, a large-diameter solenoid is indispensable for stably generating a uniform magnetic field having a desired magnetic field strength between the magnetic poles. , Solenoid and X
This causes interference with the wafer on the YZ stage and greatly restricts the movement range of the wafer. As a result, it is very difficult to perform the sensitivity characteristic evaluation on all the TMR elements on the wafer with the known sensitivity characteristic evaluation device.

Further, in order to evaluate the sensitive characteristics with high accuracy, it is necessary to accurately form a magnetic field that traverses the TMR element and ensure the contact of the probe with the TMR element. With respect to the devising for this, no publicly-known sensitive characteristic evaluation device is disclosed. The present invention has been made based on the above-mentioned circumstances, and an object thereof is to evaluate the sensitivity characteristic of a magnetoresistive element, which has high feasibility in highly sensitively evaluating the sensitivity characteristic of the magnetoresistive element. To provide a device.

[0008]

In order to achieve the above object, the present invention provides a wafer table on which a wafer on which a large number of magnetoresistive elements are formed is placed, and which wafer can be heated to a predetermined temperature, and a wafer. The table is moved in the horizontal plane in the front, rear, left, right, up, and down directions, and is rotated in a horizontal plane, thereby arranging any magnetoresistive element of the wafer at the inspection position to be the element to be inspected, and the table moving means and arranged above the inspection position. Is
It has an electromagnet unit that forms a horizontal external magnetic field that crosses the element to be inspected in an arbitrary direction, and a plurality of probes that can electrically contact the input / output terminals of the element to be inspected. The evaluation device according to claim 1 is characterized in that the input device can be applied and the probe holder that extracts the sensitive output of the element to be inspected with respect to an external magnetic field is provided.

That is, the electromagnet unit according to claim 1 is
An electromagnet having a pair of cores facing each other and solenoids attached to the cores, which are arranged on a horizontal plane above the inspection position, and extend from each core toward the inspection position. An extended magnetic path forming member that closely faces and faces as a magnetic pole immediately above the inspection position beyond the outer circumference is included.

According to the above-mentioned sensitive characteristic evaluation apparatus, since the pair of magnetic poles of the electromagnet are positioned closer to the wafer table side than the outer circumference of the solenoid, the wafer on the wafer table moves without interfering with the solenoid. The means makes it possible to position an arbitrary magnetoresistive element on the wafer at the inspection position. Specifically, the electromagnet unit (claim 2) further includes a Hall element that is provided on one magnetic pole of the electromagnet and that measures the magnetic field strength between the magnetic poles, and a cooling unit that cools the Hall element. .

Since the output of the Hall element changes due to the temperature rise, the Hall element is cooled by the cooling means, so that the output of the Hall element accurately indicates the strength of the magnetic field formed by the electromagnet. Specifically, the cooling means (claim 3) is a cooling block which is in close contact with the distal end portion of the extended magnetic path forming member having a Hall element and has a refrigerant passage therein,
And a heat transfer path for transferring heat of the Hall element to the cooling block. In this case, the Hall element is cooled by the cooling block via the heat transfer path, and its temperature rise is suppressed.

More preferably, the cooling block (claim 4) is mounted so as to straddle between the tips of the respective extension magnetic path forming members, and has a shape having an insertion hole for allowing the insertion of the probe holder. In this case, a large heat capacity of the cooling block is ensured, and the cooling block efficiently cools the Hall element. Further, the cooling means (claim 5) preferably includes a heat insulating layer between the magnetic pole and the Hall element. In this case, the heat insulating layer blocks the heat transferred from the extended magnetic path forming member to the Hall element and prevents the Hall element from being heated.

The probe holder (claims 6 and 7) has a hollow probe insert body extending in the magnetic gap formed between the magnetic poles or the insertion hole of the cooling block and having a probe at the lower end surface thereof. According to such a probe insert, the probe on the lower end surface can be brought into contact with the input / output terminal of the inspection target element regardless of the presence of the extension magnetic path forming member and the cooling block.

Further, the sensitive characteristic evaluation apparatus can further comprise an image pickup means for picking up an image of the element to be inspected and the tip of the probe through the probe insertion body, and the image pickup means (claim 8) is arranged above the probe holder. Is
A camera unit having a lens barrel coaxial with the probe insertion body and a CCD camera, and a mounting arm (rotating arm) that supports the camera unit at one end and allows the camera unit to horizontally rotate about the other end. ) And.

When the camera unit is arranged in this way, when the probe insert body, that is, the probe holder is replaced, the camera unit is horizontally rotated through the mounting arm and retracted from above the probe holder, This allows access to the probe holder regardless of the presence of the camera unit. The sensitive characteristic evaluation device (claim 9) includes a device base, a support column that connects the device base and the electromagnet unit, and supports the electromagnet unit, and is supported by the device base via a vibration absorbing member. And a mounting table for receiving the load of the probe holder. In this case, the vibration of the electromagnet unit during energization is blocked by the vibration absorbing member, and the vibration of the electromagnet unit is not transmitted to the mounting table.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a magnetoresistive element sensitivity characteristic evaluation apparatus is provided with a base 2 as an apparatus base, and the base 2 is provided with a plurality of extendable legs 4 on a floor. It is located on F. A plurality of casters 6 are attached to the lower surface of the base 2, and the casters 6 are grounded on the floor F when the legs 4 are contracted, and the evaluation device can be moved.

Six air cushions 8 are arranged on the base 2 as vibration absorbing members, and a stage base 10 as a mounting base is supported on the air cushions 8. A wafer table 12 is arranged above the stage table 10, and the upper surface of the wafer table 12 is formed as a suction surface having a large number of suction holes (not shown).

The wafer table 12 is a table moving mechanism 1.
It is supported by the stage base 10 via the unit 4. More specifically, the table moving mechanism 14 has a XY stage 1 at the bottom thereof.
6, the XY stage 16 is arranged on the stage base 10. The XY stage 16 has movable stages 18 and 20 on its upper side and lower side, respectively, and the lower movable stage 18 is provided with a stage guide 1 via a linear guide 24.
On the other hand, the upper movable stage 20 is supported on the movable stage 18 via a linear motion guide 26 that is orthogonal to the linear motion guide 24.

Further, the movable stages 18 and 20 have feed screws 2 extending parallel to the linear motion guides 24 and 26.
8 and 30 (see FIG. 2), these feed screws 28 and 30 are connected to step motors 32 and 34, respectively. The step motors 32 and 34 rotate the feed screws 28 and 30 in the forward and reverse directions, and the rotations of the feed screws 28 and 30 cause the upper and lower movable stages 18 and 20 to be orthogonal to each other in two directions in a horizontal plane. That is, the movable stages 18 and 20 can be moved independently in the XY directions.
Of the upper movable stage 2
It is possible to position 0 at the desired position.

A Z-axis stage 36 and a θ-axis stage 38 are sequentially arranged on the upper movable stage 20, and the above-mentioned wafer table 12 is mounted on the θ-axis stage 38 via an adsorption / heater unit 40. ing. The Z-axis stage 36 has a built-in jack mechanism and can move the θ-axis stage 38 up and down within a predetermined range.
On the other hand, the θ-axis stage 38, together with the suction / heater unit 40, can rotate the wafer table 12 within a predetermined rotation angle range. Further, the suction / heater unit 40 has a suction chamber and an electric heater (neither shown) built therein, and the suction chamber supplies suction pressure to the suction holes of the wafer table 12, while
The electric heater moves the wafer table 12 to a predetermined temperature, for example, 2
It can be heated to 00 ° C.

The table moving mechanism 14 described above is electrically connected to a measurement controller (not shown), and each stage 18, 20, 3 is connected by this measurement controller.
The operations of 6, 38 and the adsorption / heater unit 40 are controlled. As shown in FIG. 2, the wafer table 12 is supplied with the wafer W made of semiconductor on its upper surface at the position P ₁ . The wafer W is suction-held on the upper surface of the wafer table 12, that is, the suction surface, and the wafer table 1
It is heated to 200 ° C. via 2, for example. After this, X
In response to the operation of the Y stage 16, the wafer table 12 moves together with the wafer W in a substantially L-shaped movement path from the P ₁ position to the P ₂ position to the P ₃ position. While the wafer W is moving, the Z-axis stage 36 lowers the θ-axis stage 38, that is, the wafer table 12, but by raising the wafer table 12 at the P ₃ position, the wafer W is moved.
The upper surface of the can be positioned at the inspection position level.

Here, on the wafer W, magnetoresistive elements, that is, the above-mentioned TMR elements are formed in an integrated manner, and these TMR elements are arranged in a lattice pattern. More specifically, as shown in FIG. 3, each TMR element E has, for example, four input / output terminals T in the vicinity thereof according to a predetermined array pattern, and these input / output terminals T are exposed on the upper surface of the wafer W. Is in a state. The formation region of each TMR element E including the input / output terminal T is accommodated within a region of 0.4 × 0.4 mm, for example.

Directly above the wafer table 12 at the P ₃ position is a box-shaped electromagnet unit 42 as shown in FIG.
Are arranged, and the electromagnet unit 42 is supported by four columns 44 standing from the base 2 via a square frame 46. As shown in FIG. 2, the electromagnet unit 42 is located substantially in the center between the above-described P ₂ position and P ₃ position, and can apply a magnetic field to all points of the wafer W on the wafer table 12.

As shown in FIGS. 4 and 5, the electromagnet unit 42 includes a square frame 48 made of a magnetic material.
The core 50 projects from each inner wall of the frame 48. These cores 50 are arranged in the same horizontal plane, and solenoids 52 are attached to each core 50. That is, the cores 50 facing each other and the solenoids 52 mounted on these cores 50 constitute an electromagnet, and the electromagnet unit 42 includes two electromagnets.

Further, the solenoid 52 of each electromagnet is surrounded by a cooling jacket 54 composed of a cooling pipe, and the cooling jacket 54 is supplied with cooling water as a refrigerant, so that the corresponding solenoid 52 can be operated. Cooling. In each electromagnet, an extension magnetic path forming member, that is, a yoke 56 extends from each core 50 toward the center of the frame 48, and the tips of these yokes 56 are paired with a pair of magnetic poles 58 that closely oppose each other in the center of the frame 48. And a pair of magnetic poles 58 of each electromagnet have their facing directions orthogonal to each other. Here, a magnetic gap of, for example, 30 mm is formed between each pair of magnetic poles 58.
In addition, each electromagnet is electrically connected to the above-described measurement controller, and the measurement controller controls the energization of each electromagnet. The magnetic poles 58 are arranged in orthogonal positions with two opposing magnetic poles as a set, and a total of two magnetic poles are applied to the surface of the wafer W to change the ratio of the magnetic field strengths generated by the two magnetic poles. , A magnetic field can be generated in any direction.

In detail regarding the yokes 56, each yoke 56 is a vertical portion 56 that vertically descends from the core 50 to the outer periphery of the solenoid 52, that is, beyond the lower surface of the frame 48.
_V and a horizontal portion 56 _H extending horizontally from the lower end of the vertical portion 56 _V toward the center of the frame 48. As is clear from FIG. 5, the horizontal portion 56 _H is tapered toward the center of the frame 48. It is in a state. Therefore, when the magnetic pole 58 described above is viewed in the radial direction of the solenoid 52,
Is located below the outer circumference of the.

A degaussing coil 60 is attached to each core 50 at the end on the yoke 56 side, and these degaussing coils 60 are used to remove the residual magnetic field of the yoke 56. Further, a receiving surface 62 (FIG. 4) which is inclined downward toward the magnetic pole 58 is formed on the top surface of each yoke 56, and a cooling block 64 (FIG. 5) is closely attached to the receiving surface 62 of these yokes 56. It is installed in the state.

The cooling block 64 is made of brass having excellent heat conductivity and has a downward facing truncated pyramid shape as shown in FIG. A square insertion hole 66 is formed in the center of the cooling block 64, and the insertion hole 66 penetrates the cooling block 64 vertically. Sensor holders 68 are attached to a pair of inner walls adjacent to each other in the insertion hole 66.
These sensor holders 68 have an elongated plate shape, extend from the upper surface of the cooling block 64 over the lower surface, and project below the cooling block 64.

Further, a cooling medium passage 70 is formed in the cooling block 64, and the cooling medium passage 70 is formed in the cooling block 6.
Inlet 72 opening at each corner located on the diagonal of 4
And an outlet 74. More specifically, as shown in FIG. 7, the refrigerant passage 70 sequentially passes from the inlet 72 in the vicinity of the pair of sensor holders 68 and then extends toward the outlet 74.

In FIG. 7, reference numeral 76 indicates an insertion hole of a bolt for fixing the cooling block 64 to the receiving surface 62 of the yoke 56, and reference numeral 78 closes the hole used for forming the refrigerant passage 70. Shows the plug. At the inlet 72 and the outlet 74 of the refrigerant passage 70, a coolant introduction pipe 80 is provided.
And a discharge pipe 82 (see FIG. 5) are connected to each other, and the introduction pipe 80 and the discharge pipe 82 are connected to a cooling liquid circulation device (not shown). Therefore, the cooling block 64 is cooled by receiving the supply of the cooling liquid circulated by the cooling liquid circulation device.

As shown in FIG. 8, a cooling block 64
Is attached to the receiving surface 62 of each yoke 56, the upper surface of the cooling block 64 is flush with the upper surface of the yoke 56, and the lower end portions of the pair of sensor holders 68 protruding from the lower surface of the cooling block 64 correspond to each other. Magnetic pole 58 of the yoke 56
Located adjacent to. As is clear from FIG. 9, each sensor holder 68 has a brass holder plate 84 having excellent thermal conductivity, and the holder plate 84 is the cooling block 6.
It is in close contact with the magnetic pole 58 of the yoke 56 from the inner surface of 4, and is fixed to the cooling block 64 via mounting screws (not shown). The holder plate 84 is covered with a heat-resistant cover 86, and the cover 86 and the holder plate 8 are
4 and an insertion space for the element substrate 88 are formed between them. The element substrate 88 is made of a material having excellent thermal conductivity, and has a Hall element 90 at its lower end. Hall element 90
Measures the magnetic field strength formed between the magnetic poles 58, and the measurement result is output to the measurement controller via the element substrate 88. As a result, the measurement controller causes the hall element
On the basis of the output from, the energization of each electromagnet in the electromagnet unit 42 is controlled to form a desired horizontal magnetic field between the magnetic poles 58.

Further, as shown in FIG. 9, a heat insulating sheet 92 made of ceramic is disposed between the magnetic pole 58 and the holder plate 84, and this heat insulating sheet 92 is used for the magnetic pole 58.
Pasted on. On the other hand, a ceramic probe holder 94 is inserted through the insertion hole 66 of the cooling block 64. More specifically, the probe holder 94 has a probe insert 96 that can be inserted into the insert hole 66, and this probe insert 96 has a through hole 97 in the center thereof and is hollow. The upper end of the probe insert 96 projects from the cooling block 64, and the mounting flange 98 is attached to this upper end.
Are integrally formed. The lower end surface of the blow insert 96 is positioned flush with the lower surface of the yoke 56, that is, the lower edge of the magnetic pole 58, and a plurality of tungsten probes 100 are projected from this lower end surface. These probes 10
The number of 0s is the same as the number of the input / output terminals T in the TMR element E described above, and the array pattern thereof is also the same as the array pattern of the input / output terminals T.

The probe 100 is electrically connected to the measurement controller via the probe holder 94, and also shown in FIG.
In the figure, the reference symbol G indicates an enlarged gap between the tips of the probe 100. As is apparent from FIG. 8, the probe holder 94 is attached to the stepped mounting hole of the mounting plate 102 through its mounting flange 98, and
The mounting plate 102 is arranged on a plurality of support fingers 104. More specifically, the mounting flange 98 is positioned on the mounting plate 102 via locating pins 106 and is retained on the mounting plate 102 via clips 110 by screwing in the tightening bolts 108.

On the other hand, each of the supporting fingers 104 extends horizontally toward the mounting plate 102 from the outside of the electromagnet unit 42 while avoiding the yoke 56, and its base end is a horizontal supporting frame 112 as shown in FIG. Installed on. The support frame 112 is supported by the stage base 10 via, for example, four support rods 114. Furthermore, FIG.
The camera unit 116 is arranged above the probe holder 94 as shown in FIG.
Reference numeral 6 includes a zoom lens barrel 118 and a CCD camera 120 attached to the upper end of the zoom lens barrel 118. The zoom lens barrel 118 is surrounded by the yoke 56 while being positioned coaxially with the through hole 97 of the probe insert 96, and the CCD camera 120 displays the image captured through the zoom lens barrel 118 on a monitor (not shown). Output is possible.

Further, as shown in FIG. 10, the camera unit 116 has the upper part of the zoom lens barrel 118 attached to the tip of the rotary arm 122, and the base end of the rotary arm 122 is mounted on the bracket 124 in a horizontal plane. Is rotatably attached. The bracket 124 is the electromagnet unit 4
The column 1 that extends directly above the column 2 and is arranged beside the electromagnet 42
It is attached to the upper end of 26.

According to the above-mentioned sensitive characteristic evaluation device, P ₃
The wafer W positioned at the position is moved to the desired TMR element E through the operation of the XY stage 16 and the θ axis stage 38.
Is positioned as an inspection target element immediately below the probe 100 of the probe holder 94, that is, immediately below the inspection position. Thereafter, the wafer W, that is, the inspection target element is raised to the inspection position by the Z-axis stage 36, and at this inspection position, each probe 100 of the probe holder 94 is respectively connected to the corresponding input / output terminal T of the inspection target element. Contact,
The electrical connection between the probe 100 and the input / output terminal T is established.

At this time, in the CCD camera 120 of the camera unit 116 described above, the contact state between the probe 100 and the input / output terminal T is determined by the through hole 97 of the probe holder 94.
The image is output through the monitor and the image is output to the monitor. From the output image of this monitor, the probe 100 and the input / output terminal T
When it is determined that the contact state between the wafer W and the substrate is incomplete, the wafer W is once lowered via the measurement controller, and the XY stage 16 or the θ-axis stage 38 is moved to complete the contact state. The position of the wafer W is finely adjusted to accurately position the inspection target element at the inspection position.

In this state, a required input is applied to a predetermined input / output terminal T of the element to be inspected through the probe 100, while one of the electromagnets of the electromagnet unit 42 is energized. In response to this energization, a magnetic field is formed between the pair of magnetic poles 58 of the electromagnet, and the magnetic field traverses the element to be inspected in the desired horizontal direction. Here, the magnetic field strength formed between the magnetic poles 58 is measured by the Hall element 90 of the corresponding sensor holder 68, and the output from the Hall element 90 controls the energization of the electromagnet. Magnetic field can be generated.

When such an external magnetic field crosses the element to be inspected, the characteristics such as the magnetic resistance in the element to be inspected change, and this change is caused from the predetermined input / output terminal T to the probe 100.
To the measurement controller. As a result, the measurement controller can evaluate the sensitivity characteristic of the device under test based on the output result from the probe 100.

The above-mentioned sensitive characteristic is the table moving mechanism 1
All the TMR elements E of the wafer W are moved by moving the wafer W by 4 and positioning each TMR element E at the inspection position.
Will be carried out against. Here, since the TMR elements E are accurately arranged in a grid pattern, the camera unit 116 is used to position the first TMR element E at the inspection position, and thereafter, the TMR elements E are moved by the table moving mechanism 14. E can be accurately positioned at the inspection position.

The magnetic pole 58 of each electromagnet described above is a yoke 56.
Is formed at the tip of the solenoid 52 and is positioned below the outer circumference of the solenoid 52. Therefore, even if the wafer W is moved, the solenoid 52 does not interfere with the wafer W, and the sensitivity characteristics of all the TMR elements E of the wafer W can be easily evaluated. Further, as described above, since the wafer W is heated to a high temperature of 200 ° C. during the evaluation of the sensitive characteristic, the Hall element 90 of the sensor holder 68 is also exposed to the heat from the wafer W. However, while the Hall element 90 is covered by the cover 86 of the sensor holder 68, and the element substrate 88 thereof is in close contact with the cooling block 64 via the holder plate 84, the Hall element 90 moves from the cooling block 64 to the holder. It is cooled via the plate 84. As a result, the temperature of the Hall element 90 on the sensor substrate 88 can be maintained constant, so that the magnetic field strength formed between the magnetic poles 58 can be accurately measured. As a result, the element to be inspected can be placed in a desired magnetic field, and the sensitive characteristics of the element to be inspected can be evaluated with high accuracy.

Since the cooling block 64 has a downwardly-facing quadrangular truncated pyramid shape mounted on the receiving surface 62 formed at the tip of each yoke 56, it can be easily arranged near the Hall element 90, and It is possible to secure a large heat capacity. Therefore, the cooling effect of the Hall element 90 by the cooling block 64 is high. Moreover, since the heat insulating sheet 92 is interposed between the magnetic pole 58 and the sensor holder 68, even if the yoke 56 is heated by the heat from the wafer W, the heat transfer from the yoke 56 to the Hall element 90 is reduced. be able to.

The probe holder 94 includes the cooling block 64.
Since it has the probe insert 96 extending through the insertion hole 66 of the probe 100, the probe 100 is attached to the lower end surface of the probe insert 96.
By providing the, the probe 100 can be easily brought into contact with the input / output terminal T of the element to be inspected regardless of the presence of the yoke 56 and the cooling block 64. Further, since the electromagnet unit 42 is supported by the base 2 via the pillars 44, the weight of the electromagnet unit 42 is less than that of the stage base 10.
Do not join. Therefore, a small air cushion 8 that supports the stage base 10 can be used.

Further, each electromagnet of the electromagnet unit 42 vibrates as the solenoid is energized, but this vibration is interrupted by the air cushion 8 and the vibration of the electromagnet unit 42 is transmitted to the wafer W and the probe holder 94. There is no. Furthermore, the probe holder 94 has the type of the magnetoresistive element whose sensitivity characteristic is to be evaluated, that is, the probe 100 according to the number of its input / output terminals and the arrangement pattern, and the type of the magnetoresistive element is different. In some cases, it is necessary to replace with a corresponding probe holder 94. Here, since the camera unit 116 located above the probe holder 94 is rotatable in a horizontal plane, when the probe holder 94 is replaced, the camera unit 116 is rotated so that the camera unit 116 is moved from above the probe holder 94 to the side. The probe holder 94 can be easily and quickly replaced.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in one embodiment, the yoke 56 extending from the core 50 has an L-shaped cross section, but the yoke 56 is not limited to this L-shaped cross section, and the yoke 56 extends straight from the core 50 toward the inspection position. Good. Further, the shape of the cooling block 64 is not limited to the downward facing truncated pyramid shape.

[0046]

As described above, according to the sensitive characteristic evaluation device for a magnetoresistive element of the present invention (claim 1), the electromagnet of the electromagnet unit is provided at the tip of the extended magnetic path forming member extending from the pair of cores. Since the magnetic poles are formed, the pair of magnetic poles of the electromagnet can be positioned closer to the wafer table side than the outer circumference of the solenoid, and as a result, the wafer can move without interfering with the solenoid,
By easily positioning the individual magnetoresistive elements on the wafer at the inspection position, the sensitive characteristics of the magnetoresistive elements can be accurately evaluated.

Further, since the sensitive characteristic evaluation device is provided with the cooling means for the hall element (claims 2 to 4), the hall element can accurately measure the magnetic field strength and accurately generate the desired magnetic field between the magnetic poles. be able to. Further, if the cooling means is provided with the cooling block mounted across the tips of the respective extension magnetic path forming members, a large heat capacity of this cooling block can be secured and the Hall element can be effectively cooled.

Further, if the heat insulating layer is interposed between the magnetic pole and the Hall element (claim 5), the temperature rise of the Hall element can be prevented more effectively. If the probe holder has a hollow probe insert (claim 6,
7) The probe can be accurately brought into contact with the input / output terminals of the magnetoresistive element regardless of the presence of the extended magnetic path forming member and the cooling block.

If the camera unit arranged above the probe holder can be retracted laterally (claim 8), the probe holder can be easily replaced. Furthermore, the electromagnet unit is supported separately from the wafer table and probe holder side, and
If the vibration absorbing member is interposed between these supporting systems (claim 9), not only the vibration absorbing member can prevent the vibration from being transmitted from the electromagnet unit to the wafer table and the probe holder, but also the vibration can be prevented. Since the weight of the electromagnet unit is not added to the absorbing member, a small vibration absorbing member can be used.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a sensitive characteristic evaluation device of an example.

FIG. 2 is a plan view of a table moving mechanism in the sensitivity characteristic evaluation device of FIG.

FIG. 3 is an enlarged plan view of a TMR element.

FIG. 4 is a sectional view of an electromagnet unit.

FIG. 5 is a plan view of an electromagnet unit.

FIG. 6 is a side view of a cooling block.

FIG. 7 is a bottom view of the cooling block.

FIG. 8 is a cross-sectional view around a probe holder.

9 is an enlarged cross-sectional view of the IX portion in FIG.

FIG. 10 is a view of the camera unit seen from above.

[Explanation of symbols]

2 bases 10 stage stand 12 Wafer table 14 Table moving mechanism (table moving means) 42 Electromagnet unit 50 cores 52 solenoid 56 Yoke (extended magnetic path forming member) 58 magnetic pole 64 cooling block 66 insertion hole 68 Sensor holder 70 Refrigerant passage 84 Holder plate 86 cover 90 Hall element 92 Heat insulation sheet (heat insulation layer) 94 probe holder 96 probe insert 100 probes 116 camera unit 122 Rotating arm (mounting arm) E TMR element (magnetoresistive element) T input / output terminal W wafer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/66 H01L 43/06 U 43/06 43/08 Z 43/08 G01R 33/06 R (72) Inventor Takaaki Kawai 10 Ryugu-cho, Minato-ku, Aichi Prefecture Daido Special Steel Co., Ltd., Tsukiji Plant (72) Inventor Kazuhiko Okita Nishigataoka, Murata-cho, Shibata-gun, Miyagi Prefecture 23 F-term in Tohoku Special Steel Co., Ltd. Reference) 2G003 AA00 AA10 AG03 AG16 AH05 2G017 AA01 AD55 CB24 CB26 4M106 AA01 AB07 BA01 BA14 BA20 CA10 DD30

Claims (9)

[Claims] 1. A wafer table on which a large number of magnetoresistive elements are mounted and which can heat the wafer to a predetermined temperature, and the wafer table is added in front, rear, left, right, up, and down three axial directions,
By rotating in the horizontal plane, table moving means for positioning an arbitrary magnetoresistive element of the wafer at an inspection position to be an inspection target element, and arranged above the inspection position, the inspection target element in an arbitrary direction. And an electromagnet unit that forms a horizontal external magnetic field that traverses each other, and a plurality of probes that can electrically contact the input / output terminals of the element to be inspected, and a desired input can be applied to the element to be inspected through these probes. And a probe holder for taking out the sensitive output of the element to be inspected to the external magnetic field, wherein the electromagnet unit is arranged on a horizontal plane above the inspection position, and is attached to a pair of cores facing each other and these cores, respectively. An electromagnet having a solenoid, and extending from each core toward the inspection position, respectively, in a radial direction of the solenoid. A magnetoresistive element sensitivity characteristic evaluation device, characterized in that it includes an extended magnetic path forming member whose ends are opposed to each other as magnetic poles immediately above the inspection position beyond the outer circumference of the solenoid. 2. The electromagnet unit further includes a Hall element that is provided on one magnetic pole of the electromagnet and that measures a magnetic field strength between the magnetic poles, and a cooling unit that cools the Hall element. The sensitive characteristic evaluation device for a magnetoresistive element according to claim 1. 3. The cooling means is a cooling block which is in close contact with a tip end portion of the extension magnetic path forming member having the hall element and has a refrigerant passage therein, and heat of the hall element to the cooling block. 3. The sensitive characteristic evaluation device for a magnetoresistive element according to claim 2, further comprising a heat transfer path for transfer. 4. The cooling block is mounted so as to straddle between the tips of the extension magnetic path forming members, and has a shape having an insertion hole that allows insertion of the probe holder. Item 5. The magneto-resistive element sensitivity characteristic evaluation device according to Item 3. 5. The magnetoresistive element sensitivity characteristic evaluation device according to claim 2, wherein the cooling unit further includes a heat insulating layer between the magnetic pole and the Hall element. 6. The probe holder according to claim 1, wherein the probe holder has a hollow probe insert body extending in a magnetic gap formed between the magnetic poles and having the probe on a lower end surface thereof. Sensitive characteristic evaluation device for magnetoresistive element. 7. The probe holder has a hollow probe insert body that extends in the insertion hole of the cooling block and has the probe on the lower end surface thereof.
The magneto-resistive element sensitivity characteristic evaluation device according to. 8. An image pickup means for picking up an image of the element to be inspected and the tip of the probe through the probe insert body, wherein the image pickup means is arranged above the probe holder and coaxial with the probe insert body. A camera unit having a tube and a CCD camera, and an attachment arm that supports the camera unit at one end and allows the camera unit to rotate in the horizontal direction about the other end. Item 6. The sensitive characteristic evaluation device for a magnetoresistive element according to Item 6 or 7. 9. A device base, and a connection between the device base and the electromagnet unit,
The column further comprises: a support column that supports the electromagnet unit; and a mounting table that is supported by the apparatus base via a vibration absorbing member and receives a load of the table moving unit and the probe holder.
The magneto-resistive element sensitivity characteristic evaluation device according to.