JPH09166653A - Coil for magnetic-flux detection and magnetic-flux detection probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a magnetic flux with high spatial resolution by arranging one pair of loops, in which very small loop-shaped parts and two terminal parts each are brought close, on the face of an insulating wafer so as to be symmetric with respect to a line and forming them as conductive thin-film patterns. SOLUTION: One pair of loops by a first loop in which a very small loop-shaped part 15 in a diameter of about 0.1 to several mm or lower and terminal parts 15A, 15B are brought close and by a second loop in which a very small loop-shaped part 16 in the same manner as the loop-shaped part 15 and terminal parts 16A, 16B are brought close are arranged in such a way that they are brought close to each other in a congruence shape and that they are arranged so as to be symmetric with respect to a line, and they are formed on the face of an insulating wafer as conductive thin-film patterns. Then, the terminal parts 15A, 16A and a differential circuit 18 are impedance-matched by resistances 20, 20', the difference between respective interminal voltages across the terminal parts 15A, 15B and across the terminal parts 16A, 16B is set by the differential circuit 18, and only an electromagnetic inductive component by a magnetic flux is obtained. It is amplified by an amplifier circuit 19, a frequency is decomposed, and change in a magnetic flux density can be detected for every frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic flux detecting coil and a magnetic flux detecting probe.

[0002]

2. Description of the Related Art Detecting a magnetic flux using electromagnetic induction is widely carried out including measures against EMI (electro-magnetic interference). "Magnetic flux detection coil" for detecting magnetic flux
For example, those disclosed in Japanese Utility Model Laid-Open No. 6-40885 and Japanese Patent Laid-Open No. 62-106379 are known.

However, the magnetic flux detecting coil disclosed in Japanese Utility Model Laid-Open No. 6-40885 detects the influence of the electric field as well as the magnetic flux, and it is not easy to correct the influence of the electric field. The magnetic flux detecting coil disclosed in Japanese Patent Laid-Open No. 62-106379 can remove the influence of the electric field and detect only the magnetic flux, but it is difficult to "make the loop of the magnetic flux detecting coil small". It is difficult to increase the spatial resolution, and it is not suitable for the purpose of detecting leakage magnetic flux from a circuit board such as a surface-mounted LSI, and magnetic flux is detected three-dimensionally including its direction. Is also difficult.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, it is an object of the present invention to eliminate the influence of an electric field in a magnetic flux detecting coil and to enable magnetic flux detection with high spatial resolution (claims 1 and 2). 2).

Another object of the present invention is to enable three-dimensional detection of magnetic flux in a magnetic flux detecting coil with a high spatial resolution by eliminating the influence of an electric field (claim 3). Another object of the present invention is to eliminate the influence of an electric field in a magnetic flux detection probe and enable magnetic flux detection with high spatial resolution (claims 4 to 7).

[0006]

A magnetic flux detecting coil according to a first aspect of the present invention has a pattern of "a pair of loops" formed on a surface of an insulating wafer as a "conductive thin film pattern". Each of the pair of loops has “a minute loop-shaped portion and two terminal portions connected to this”, and the two terminal portions are close to each other.

The pair of minute loops are arranged "axisymmetrically in close proximity to each other".

In the magnetic flux detecting coil according to the second aspect, the "loop pattern" is formed as a "conductive thin film pattern" on the surface of the insulating wafer. "Loop pattern"
Has "a minute loop-shaped portion and a terminal portion connected to this" on both sides of the linear portion connected to the common terminal portion and having the linear portion as a common portion and line-symmetrically with respect to the linear portion.

Each terminal portion connected to the minute loop-shaped portion constitutes "two pairs of terminals" with the common terminal portion as a counterpart.

In the magnetic flux detecting coils according to claims 1 and 2, "the loop portion is minute" means that the "diameter" in the loop portion is about 0.1 mm to several mm or less. . Since the loop-shaped portion is small as described above, the magnetic flux can be detected with an extremely high spatial resolution.
Since the coil is formed as a "thin film pattern", it can be formed easily and surely by the film forming technique and the patterning technique such as etching although it is extremely minute.

A magnetic flux detecting coil according to claims 1 and 2 is
Since the pair of loop-shaped portions are formed “close to each other and line-symmetrical”, when the difference between the voltages generated in each of the two pairs of terminals is taken, it is generated in each pair of terminals due to the influence of the electric field. The voltages can be canceled out from each other, and the influence of the electric field can be removed to effectively detect only the induced voltage due to the magnetic flux.

A magnetic flux detecting coil according to a third aspect is formed by integrating three magnetic flux detecting coils according to the first or second aspect so that "the conductive thin film pattern forming surfaces are orthogonal to each other". In this way, the three orthogonal components of the magnetic flux can be detected by the three coils that are orthogonal to each other, so that the magnetic flux can be three-dimensionally detected by combining them.

A magnetic flux detecting probe according to a fourth aspect includes the magnetic flux detecting coil according to the first aspect, a differential circuit, and an amplifying circuit.

The "differential circuit" is a circuit which receives the voltage between the terminals of the two pairs of terminals in the magnetic flux detecting coil according to claim 1 and outputs the difference between the voltage between these terminals. The "amplifier circuit" is a circuit that amplifies the output of the differential circuit.

A magnetic flux detecting probe according to a fifth aspect includes the magnetic flux detecting coil according to the second aspect, a differential circuit, and an amplifying circuit.

The "differential circuit" is a circuit which receives a voltage between terminals of two pairs of terminals in the magnetic flux detecting coil according to claim 2 and outputs a difference between the voltage between the terminals. The "amplifier circuit" is a circuit that amplifies the output of the differential circuit.

The magnetic flux detecting probe according to claim 6 is characterized in that in the magnetic flux detecting probe according to claim 4 or 5, it has "a pair of impedance resistors".

The pair of "impedance resistors" are resistors for impedance matching the voltage between the terminals of the two pairs of terminals to the differential circuit. The magnetic flux detection probe according to claim 6 can detect "high frequency magnetic flux".

A magnetic flux detecting probe according to a seventh aspect is a probe for three-dimensionally detecting a magnetic flux, which has three magnetic flux detecting probes according to the fourth, fifth or sixth aspects, and three magnetic flux detecting probes. Probes are combined so that the conductive thin film pattern forming surfaces of the magnetic flux detecting coils of each magnetic flux detecting probe are orthogonal to each other.

In the magnetic flux detecting probe according to any one of claims 4 to 7, the output of the amplifier circuit is "spectrum
By inputting into the analyzer, the relative intensity of the magnetic flux for each frequency can be detected.

[0021]

Embodiments of the present invention will be described below.

FIG. 1A is a plan view showing an embodiment of the magnetic flux detecting coil according to the present invention.

"A minute loop-shaped portion 15 and a first loop in which two terminal portions 15A and 15B connected to the minute loop are close to each other" and "A minute loop-shaped portion 16 and two terminal portions 16A and 16B connected to the minute loop-shaped portion 16. A pair of loops that are adjacent to each other and have a congruent shape, and are arranged in line symmetry with respect to a “symmetry line” shown by a chain line in the figure, and have insulating properties. It is formed on the surface of the wafer 17 as a “conductive thin film pattern”.

The pattern formed by the pair of loops may be "each loop is close to each other and is line-symmetric with each other".
Various pattern configurations are possible. Pattern form 3
An example is shown in FIGS.

The pattern shown in FIG. 1 (b) is a semi-circle or semi-elliptical micro-loop portion 150, a first loop in which two terminal portions 150A and 150B connected to the micro loop portion 150 are in close proximity, and a semi-circle. Alternatively, a semi-elliptical minute loop-shaped portion 160 and two terminal portions 160 connected to the minute loop-shaped portion 160.
A and 160B are a pattern in which a pair of loops including a second loop adjacent to each other and A and 160B are adjacent to each other and are arranged line-symmetrically.

The pattern shown in FIG. 1C is "triangular".
A small loop-shaped portion 151 and a first loop in which two terminal portions 151A and 151B connected to the minute loop-shaped portion 151 are close to each other,
This is a pattern in which a pair of loops including a minute loop-shaped portion 161 having a triangular shape and a second loop in which two terminal portions 161A and 161B connected to the triangular loop portion are adjacent to each other and arranged line-symmetrically.

The pattern shown in FIG. 1D is a first pattern in which a minute loop-shaped portion 152 having a "circular or elliptical shape" and two terminal portions 152A and 152B connected to the minute loop-shaped portion 152 are close to each other.
Loop, a minute loop-shaped portion 162 having a circular or elliptical shape, and two terminal portions 162A, 1 connected to this
62B is a pattern in which a pair of loops including a second loop and a second loop 62B are arranged close to each other and are arranged line-symmetrically.

FIG. 2 is a diagram showing one embodiment of the magnetic flux detecting probe according to the present invention.

Terminal portions 15A, 15 of "conductive thin film pattern" constituting the magnetic flux detecting coil shown in FIG.
B, 16A and 16B are connected to the differential circuit 18. In this embodiment, the magnetic flux to be detected contains a high frequency component, and between the terminal portions 15A and 16A and the differential circuit 18,
Impedance resistors 20 and 20 'are respectively interposed. The output of the differential circuit 18 is input to the amplifier circuit 19.
The output of the amplifier circuit 19 is input to the "spectrum analyzer". Of course, the impedance between the differential circuit 18 and the amplifier circuit 19 is matched.

The loop-shaped portions 15 and 16 shown in FIG.
Are linearly symmetric with respect to each other, so that when the magnetic flux density of the detected magnetic flux changes in each loop, the inductive potential according to that changes, the terminals 15A and 16A have the same polarity, and the terminal 15
B and 16B have the same polarity. The potentials generated by the action of the electric field have the same polarity between the terminal portions 15A and 16B and the same polarity between the terminal portions 15B and 16A.

Voltage between terminals by the terminals 15A and 15B:
The [Delta] V _15, components of the electromagnetic induction caused by magnetic flux: [Delta] V _15M and components due to the influence of the electric field: Separating the [Delta] V _15E "[Delta] V ₁₅ = [Delta] V
_15M + ΔV _15E ”, and the inter-terminal voltage by the terminal portions 16A and 16B: ΔV ₁₆ and the electromagnetic induction component by the magnetic flux: ΔV
_16M and component due to the influence of electric field: ΔV _16E
16 = ΔV _16M + ΔV _16E ”.

Since the loop-shaped portions 15 and 16 are minute, close to each other, and arranged in line symmetry, after impedance matching is performed by the impedance resistors 20 and 20 ', -ΔV _15M = ΔV _16M , And ΔV _15E = Δ
It is V _16E .

Therefore, in the differential circuit 18, the voltage between terminals: ΔV
_If the difference between ₁₅ and ΔV ₁₆ : ΔV ₁₅ −ΔV ₁₆ is taken, this is “(ΔV _15M + ΔV _15E ) − (ΔV _16M + ΔV _16E )”, and the above relation: −ΔV _15M = ΔV _16M , ΔV _15E = ΔV
Considering _16E , ΔV ₁₅ −ΔV ₁₆ = 2ΔV _15M ,
Since only the electromagnetic induction component due to the magnetic flux is amplified by the amplifier circuit 19 and frequency-resolved by the spectrum analyzer, the change in magnetic flux density can be detected for each frequency. The impedance resistors 20 and 20 ′ may be omitted when it is known that “the magnetic flux to be detected does not include a high frequency component”.

FIG. 3A is a plan view showing an embodiment of the magnetic flux detecting coil according to the present invention.

A linear portion 230 connected to the common terminal portion 23
"Loop pattern" having linear loop portions 230 as common portions and having minute loop-shaped portions 24A and 24B and terminal portions 21 and 22 connected to these portions on both sides of the Was formed as a "conductive thin film pattern" on the surface of the insulating wafer 17 similar to that in the form of FIG. 1 (a). Terminal 21 and common terminal 2
3 constitutes "one terminal pair", and the terminal portion 22 and the common terminal portion 23 constitute "other terminal pair".

The loop pattern only needs to be "the portions on both sides of the common linear portion are line-symmetric with respect to the linear portion", and various pattern forms are possible. Three examples of the form of the loop pattern are shown in FIGS.

In the loop pattern shown in FIG. 3B, the linear portion 231 connected to the common terminal portion 23A is used as a common portion, and the linear portion 231 is used as a symmetry line to form a "circular or elliptical shape". Loop-shaped portion 241A,
241B and terminal portions 21A and 22A that are continuous with these.

The loop pattern shown in FIG. 3C is a minute loop which forms a "quadrilateral shape" with the straight line portion 232 connected to the common terminal portion 23B as a common portion and the straight line portion 232 as a symmetry line. Shaped portions 242A, 242B
And a pattern having terminal portions 21B and 22B connected to these.

The loop pattern shown in FIG. 3D is a minute loop having a "circular or elliptical shape" with the straight line portion 233 connected to the common terminal portion 23C as a common portion and the straight line portion 233 as a symmetry line. Portion 243A, 24
3B and a pattern having terminal portions 21C and 22C continuous with these.

FIG. 4 is a diagram showing one embodiment of the magnetic flux detecting probe according to the fifth and sixth aspects.

The terminals 21 and 22 are connected to the differential circuit 18 together with the common terminal portion 23 of the conductive thin film pattern forming the magnetic flux detecting coil shown in FIG. In this embodiment also, the magnetic flux to be detected contains high frequency components,
Between the terminal portions 21 and 22 and the differential circuit 18, the impedance resistors 20 similar to those in the embodiment of FIG.
20 'is interposed. The output of the differential circuit 18 is the amplifier circuit 1.
Input to 9. The output of the amplifier circuit 19 is input to the "spectrum analyzer". Of course, the impedance between the differential circuit 18 and the amplifier circuit 19 is matched.

The loop-shaped portions 24A and 2 shown in FIG.
4B is line-symmetric with respect to the common straight line portion 230, so that when the magnetic flux density of the detected magnetic flux changes in each loop, the induced potential according to it changes between the terminals 21 and 23 with respect to the common terminal 23. Becomes Further, the potential generated by the action of the electric field has the same polarity in the terminal portions 21 and 22 with respect to the common terminal portion 23.

Since the loop-shaped portions 24A and 24B are minute and are arranged close to each other and line-symmetrically,
The absolute values of the magnetic flux component and the electric field component of the voltage generated in each loop portion are equal to each other.

Therefore, when the voltage between the two terminals whose impedance is matched is subtracted in the differential circuit 18, only the electromagnetic induction component due to the magnetic flux remains as in the embodiment of FIG.・ If the frequency is decomposed by an analyzer, the change in magnetic flux density can be detected for each frequency. If it is known that the magnetic flux to be detected does not contain high frequency components, the impedance resistors 20 and 20 'may be omitted.

In the embodiment shown in FIGS. 2 and 4, the coil portion is a “balanced circuit”, whereas the amplifier circuit 19 and the spectrum analyzer are generally an “unbalanced circuit”, and therefore the differential circuit 18 is used. Has a function of "balun for performing subtraction calculation of two input signals (voltage between two terminals) and connecting a balanced circuit and an unbalanced circuit".

5 and 6 show an embodiment of the magnetic flux detecting coil according to claim 3.

In the embodiment shown in FIG. 5, the cube-shaped block 25 has "three planes orthogonal to each other".
The magnetic flux detecting coil 26 having the form described in accordance with (a).
This is a configuration in which insulating wafers A, 26B, and 26C are attached.

In the embodiment shown in FIG. 6, the cube-shaped block 25 has three "planes orthogonal to each other" as shown in FIG.
The magnetic flux detecting coil 27 having the form described in accordance with (a).
This is a configuration in which insulating wafers A, 27B, and 27C are attached.

Instead of the cube-shaped block 25 in the embodiment of FIGS. 5 and 6, a block having another shape may be used. In principle, the three magnetic flux detection coils should have their "normal vectors" independent of each other.
That is, it may be combined so as not to be "on the same plane", but in order to detect the magnetic flux three-dimensionally with high accuracy, the normal vector is set to three orthogonal axes even from the viewpoint of easy calculation. It is rational to combine.

In the embodiment shown in FIGS. 5 and 6, if two terminal pairs of each magnetic flux detecting coil are respectively connected to an amplifier circuit via a differential circuit, a magnetic flux detecting probe capable of three-dimensionally detecting magnetic flux is provided. It can be configured (claim 7). Of course, impedance matching is performed by an impedance resistor as needed, and impedance matching between the amplifier circuit and the differential circuit is also performed.

In the above-described embodiment, the conductive thin film pattern is formed by using a known appropriate thin film deposition technique (sputtering, vacuum deposition, etc.) and thin film patterning technique (dry etching or wet etching). Can be formed. The material of the thin film is only required to be conductive, and aluminum, stainless steel, copper, various alloys, and the like can be favorably used. Further, as the insulating wafer, wafers made of various insulating materials such as a quartz wafer described later can be used.

[0052]

【Example】

Example 1 A magnetic flux detecting coil of the embodiment shown in FIG. 1 was manufactured as follows.

As the insulating wafer 17, 2 mm × 2 mm
"Quartz wafer" of the size of was prepared. On top of that, an aluminum thin film is formed by "sputtering" to a thickness of 1 μm.
Formed.

On this aluminum thin film, the pattern shown in FIG. 1 (a) was patterned by photolithography using a photoresist, and then CCl ₄ was used with the patterned photoresist pattern as a mask.
Dry etching was performed using gas as an etching gas to remove the aluminum thin film portion not covered by the mask.

Then, the photoresist mask was removed to obtain a conductive thin film pattern having a shape as shown in FIG. Each rectangular loop portion of the conductive thin film pattern has a longitudinal direction of 1 mm and a lateral direction of:
It is 0.7 mm.

The magnetic flux detecting coil thus obtained is used to construct a magnetic flux detecting probe having the structure as shown in FIG. 2, and an LSI having a pin pitch or wiring pitch of 1 mm or less is used.
It was possible to detect the leakage magnetic flux noise of the circuit board on which was mounted with extremely high spatial resolution.

Example 2 A magnetic flux detecting coil of the embodiment shown in FIG. 3 was produced as follows.

As the insulating wafer 17, 2 mm × 2 mm
"Quartz wafer" of the size of was prepared. On top of that, an aluminum thin film is formed by "sputtering" to a thickness of 1 μm.
Formed.

On this aluminum thin film, the pattern shown in FIG. 3A was patterned by photolithography using a photoresist, and then CCl ₄ was used with the patterned photoresist pattern as a mask.
Dry etching was performed using gas as an etching gas to remove the aluminum thin film portion not covered by the mask.

After that, the photoresist mask was removed to obtain a conductive thin film pattern having a shape as shown in FIG. Each rectangular loop-shaped portion in the conductive thin film pattern has a longitudinal direction of 1 mm and a lateral direction of 0.
7 mm.

Using the magnetic flux detecting coil thus obtained, a magnetic flux detecting probe having a constitution as shown in FIG. 4 is constituted, and the leakage flux of the circuit board on which the LSI is mounted with a pin pitch or wiring pitch of 1 mm or less. Noise detection was realized with extremely high spatial resolution.

[0062]

As described above, according to the present invention, the magnetic flux detecting coil and the magnetic flux detecting probe can be provided.

The magnetic flux detecting coils according to the first and second aspects and the magnetic flux detecting probe according to the fourth and fifth aspects eliminate the influence of the electric field in the magnetic flux detection and enable the magnetic flux detection with high spatial resolution.

The magnetic flux detecting coil according to the third aspect and the magnetic flux detecting probe according to the seventh aspect eliminate the influence of the electric field in the magnetic flux detection and enable three-dimensional magnetic flux detection with high spatial resolution.

The magnetic flux detection probe according to the sixth aspect can detect a high-frequency magnetic flux with a high spatial resolution by removing the influence of the electric field.

Of course, the magnetic flux detecting probe according to the present invention can be suitably used for detecting leakage magnetic flux from OA equipment and the like.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of a magnetic flux detecting coil according to claim 1;

FIG. 2 is a diagram for explaining an embodiment of a magnetic flux detection probe according to claims 4 and 6;

FIG. 3 is a diagram for explaining an embodiment of a magnetic flux detecting coil according to claim 2;

FIG. 4 is a diagram for explaining an embodiment of a magnetic flux detection probe according to claims 5 and 6;

FIG. 5 is a diagram for explaining one embodiment of the magnetic flux detecting coil according to claim 3;

FIG. 6 is a diagram for explaining another embodiment of the magnetic flux detecting coil according to claim 3;

[Explanation of symbols]

 15, 16 Minute loop-shaped portion 15A, 15B Terminal portion 16A, 16B Terminal portion 17 Insulating wafer

Claims (7)

[Claims] 1. A conductive thin film on a surface of an insulating wafer, in which a pair of minute loop-shaped portions and a pair of loops in which two terminal portions connected to the minute loop-shaped portions are arranged close to each other are arranged line-symmetrically. A coil for magnetic flux detection, which is formed as a pattern. 2. On both sides of a linear portion connected to the common terminal portion,
A loop pattern having this linear portion as a common portion and a minute loop-shaped portion which is line-symmetric with respect to the linear portion and a terminal portion connected to this is formed into a conductive thin film pattern on the surface of the insulating wafer. A magnetic flux detecting coil characterized by being formed as. 3. A magnetic flux detecting coil formed by combining three magnetic flux detecting coils according to claim 1 or 2 so that the conductive thin film pattern forming surfaces are orthogonal to each other, and for three-dimensionally detecting a magnetic flux. Magnetic flux detection coil. 4. A magnetic flux of the magnetic flux detecting coil according to claim 1, which has a differential circuit for outputting a difference in voltage between terminals of two pairs of terminals, and an amplifier circuit for amplifying the output of the differential circuit. Detection probe. 5. A magnetic flux of the magnetic flux detecting coil according to claim 2, which has a differential circuit for outputting a difference in voltage between terminals of two pairs of terminals and an amplifier circuit for amplifying an output of the differential circuit. Detection probe. 6. The magnetic flux detection probe according to claim 4 or 5, further comprising a pair of impedance resistors for impedance-matching the voltage between the terminals of the two pairs of terminals to the differential circuit. Flux detection probe that can detect the magnetic flux of. 7. A magnetic flux obtained by combining three magnetic flux detecting probes according to claim 4 or 5 or 6 such that the conductive thin film pattern forming surfaces of the magnetic flux detecting coils of each magnetic flux detecting probe are orthogonal to each other. Magnetic flux detection probe for dimensionally detecting.