JP2021117085A - Probe, measurement device, and measurement method - Google Patents

Abstract

To provide a probe capable of suppressing variations in measurements.SOLUTION: A probe for measuring an electrical property of an object under measurement has a contact surface to be brought into contact with the object under measurement. The contact surface has a maximum height Rz in a range of 3 to 8 μm, inclusive.SELECTED DRAWING: Figure 5

Description

The present invention relates to probes, measuring devices, and measuring methods.

The strain gauge manufacturing process includes a measurement process for measuring the input resistance, output resistance and output voltage of the strain gauge. This measuring step is performed to check whether the strain gauge has the designed electrical properties. The same measurement process is also performed when mounting the circuit board on the product.

In the above measurement step, for example, a probe is brought into contact with a strain gauge or a terminal of a circuit board to pass a test current. Patent Document 1 shows an example of a probe.

JP-A-2009-210443

When the probe is brought into contact with the terminal of the object to be measured (strain gauge, circuit board, etc.) and the electrical characteristics of the object to be measured are measured, the measured values may vary. That is, the results of a plurality of measurements performed on the same object under the same conditions under the same conditions may not be the same. Such variations in measured values are not desirable because they affect the reliability of the measured results.

An object of the present invention is to provide a probe capable of suppressing variation in measured values, a measuring device provided with the probe, and a measuring method using the probe.

According to the first aspect of the present invention,
A probe for measuring the electrical characteristics of an object to be measured.
It has a contact surface that comes into contact with the object to be measured, and has a contact surface.
A probe having a maximum height Rz of the contact surface of 3 μm or more and 8 μm or less is provided.

In the probe of the first aspect, an oxide film may be formed on a portion of the object to be measured that comes into contact with the contact surface.

In the probe of the first aspect, the object to be measured may be a strain gauge.

According to the second aspect of the present invention,
A measuring device for measuring the electrical characteristics of an object to be measured.
The probe of the first aspect and
A jig that holds the probe and
Provided is a measuring device including a measuring object moving mechanism that holds the measured object and brings the measured object into contact with the contact surface of the probe.

In the measuring device of the second aspect, the object to be measured moves the object to be measured so that the contact pressure between the contact surface of the probe and the object to be measured is 850 to 1150 gf / mm ^2. It may be brought into contact with the contact surface of the probe.

In the measuring device of the second aspect, a roughening member moving mechanism that holds a roughening member for roughening the contact surface of the probe and brings the roughening member into contact with the contact surface is provided. You may prepare.

In the measuring device of the second aspect, the jig may be configured to hold a plurality of the probes in a matrix, and the object moving mechanism to be measured may be configured to hold the plurality of probes in a matrix. The probe may be configured to come into contact with the object to be measured at the same time.

According to the third aspect of the present invention,
It is a measuring method for measuring the electrical characteristics of an object to be measured.
To measure the electrical characteristics of the object to be measured by bringing the contact surface of the probe of the first aspect into contact with the object to be measured.
A measuring method including roughening the contact surface is provided.

In the measurement method of the third aspect,
The roughening treatment may be performed every time a predetermined number of the objects to be measured are measured, or every time a predetermined time elapses.

According to the probe of the present invention, a measuring device provided with the probe, and a measuring method using the probe, variations in measured values can be suppressed.

FIG. 1A is a top view of the strain gauge strip. FIG. 1B is a top view of the strain gauge included in the strain gauge strip. FIG. 1C is a circuit diagram of a Wheatstone bridge configured in a strain gauge. FIG. 2 is a side view of the measuring device according to the embodiment of the present invention. FIG. 3 is a perspective view of a table included in the measuring device. FIG. 4 is a top view of the measuring device according to the embodiment of the present invention, in which a part is omitted. FIG. 5 is a side view of the probe according to the embodiment of the present invention. FIG. 6 is a flowchart of the measurement method according to the embodiment of the present invention. 7 (a) to 7 (d) are diagrams illustrating the operation of the measuring device. FIG. 7A shows a state in which the table is in the work exchange position. FIG. 7B shows a state in which the table is in the standby position. FIG. 7C shows a state in which the table is in the work measurement position. FIG. 7D shows a state in which the table is in the marking position. FIG. 8 is a table showing the determination results of the maximum height Rz and the variation for the probes of Examples 1 to 11 and the probes of Comparative Examples 1 to 3. 9 (a), 9 (b), and 9 (c) are explanatory views for explaining the influence of the change in the contact state between the contact surface of the probe and the terminal on the contact resistance. 10 (a), 10 (b), and 10 (c) are explanatory views for explaining the influence of the change in the contact state between the contact surface of the probe and the terminal on the contact resistance.

<Embodiment>
Regarding the probe 50 and the measuring device (in-circuit tester) 100 according to the embodiment of the present invention, the electrical characteristics (input resistance, output resistance, output voltage) of a plurality of strain gauges included in the strain gauge strip 900 (FIG. 1 (a)). Etc.) will be described as an example.

[Strain gauge strip 900]
As shown in FIG. 1A, the strain gauge strip 900 to be measured includes a gauge base 910 having a substantially rectangular shape in a plan view and a wiring layer 920 formed on the gauge base 910.

The gauge base 910 can be a film-like sheet formed of an insulating resin, for example, a PI (polyimide) resin, an epoxy resin, a PET (polyethylene terephthalate) resin, or the like. The thickness of the gauge base 910 can be, for example, about 20 μm to 30 μm. Alignment holes 910h that penetrate the gauge base 910 in the thickness direction are formed at each of the four corners of the gauge base 910.

The wiring layer 920 is formed of a copper-nickel alloy as an example. The wiring layer 920 includes a plurality of gauge patterns GP _{11 to GP 54} arranged in a matrix of 5 rows × 4 columns. The thickness of the wiring layer 920 may be, for example, about 3 μm to 5 μm.

Each gage patterns _GP 11 _{~GP 54} is FIG. 1 (b), the as shown in FIG. 1 (c), four resistors _{R 1, R 2, R 3} , R 4, 4 two terminals _T A, T including _{B, T} C, and _{T D,} a wire W for connecting them. _A Wheatstone bridge circuit is composed of _four resistors R _{1 to} R 4, four terminals TA to T _{D, and wiring W.}

A part of the gauge base 910 and gauge patterns GP _{11 to GP 54} formed on the part form strain gauges SG _{11 to SG 54} , respectively. Hereinafter, the gauge patterns GP _{11 to GP 54} are collectively referred to as a gauge pattern GP _mn, and the strain gauges SG _{11 to SG 54} are collectively referred to as a strain gauge SG _mn .

[Measuring device 100]
As shown in FIG. 2, the measuring device 100 includes a base 10, a drive mechanism 20 built in the base 10, a table 30 movably supported by the drive mechanism 20, and a probe holding arranged on the upper surface of the base 10. It includes a mechanism 40. The probe holding mechanism 40 holds a plurality of probes 50.

The measuring device 100 further controls the measurement executing unit 60 connected to each of the plurality of probes 50 by wiring (not shown), the marking mechanism 70 adjacent to the probe holding mechanism 40, and the overall operation of the measuring device 100. It is provided with a control unit CONT.

In the following, the left-right direction of FIG. 2 is referred to as the slide direction of the measuring device 100, and the depth direction of FIG. 2 (the direction orthogonal to the paper surface) is referred to as the width direction of the measuring device 100. The slide direction is the direction in which the drive mechanism 20 slides the table 30 along the horizontal plane, and the width direction is the direction orthogonal to the slide direction in the horizontal plane. Further, the vertical direction of FIG. 2, that is, the direction orthogonal to the slide direction and the width direction is referred to as a vertical direction. In the slide direction, the side where the table 30 is located is called the work installation side in FIG. 2, and the side where the probe holding mechanism 40 is located is called the work measurement side.

The base 10 has a hollow box shape and has a top plate 10t extending along a horizontal plane. The top plate 10t is formed with a long opening 10A (FIGS. 2 and 4) extending in the sliding direction.

The drive mechanism 20 is a mechanism for moving the table 30 in the sliding direction and the vertical direction. The drive mechanism 20 has a main body portion 21 and a support portion 22 moved by the main body portion 21.

The main body 21 is housed inside the base 10 and is located in the vicinity of the top plate 10t. The main body 21 may be any mechanism that can move the support 22 in the sliding direction and the vertical direction. As an example, the main body 21 is composed of a power generation mechanism including a motor and a piezo actuator, and a power transmission mechanism including a gear, a belt, a chain, a pulley, and the like.

The support portion 22 has a columnar structure extending in the vertical direction. The support portion 22 extends from the upper surface of the main body portion 21 through the opening 10A of the top plate 10t to the upper side of the top plate 10t.

As shown in FIG. 3, the table 30 is a flat plate having a substantially square plan view.

Each of the four corners of the upper surface 30u of the table 30 is provided with a columnar alignment pin 30p that stands upright from the upper surface 30u. A plurality of intake holes 30h arranged along each side are provided on the peripheral edge of the upper surface 30u of the table 30. Each of the plurality of intake holes 30h is an intake device via an air flow path inside the table 30 (not shown) and a flexible intake hose (not shown) connected to the table 30 and communicated with the air flow path. It is connected to (not shown).

The lower surface of the table 30 is fixed to the upper end of the support portion 22 of the drive mechanism 20. As a result, the table 30 is supported by the drive mechanism 20 in a state where it can be moved in the sliding direction and the vertical direction.

The probe holding mechanism 40 has a rectangular parallelepiped jig 41 that holds a plurality of probes 50, and four support columns 42 that support the jig 41.

As shown in FIG. 4, the jig 41 is formed with a plurality of holding holes 41h penetrating the jig 41 in the vertical direction in a matrix shape. In the present embodiment, 80 plurality of holding holes 41h (5 rows in the width direction × 16 columns in the slide direction) are formed.

The four support columns 42 extend upward from the upper surface of the top plate 10t and are connected to the four corners of the lower surface of the jig 41. The two support columns 42 arranged in the width direction sandwich the opening 10A in the width direction.

Each of the plurality of probes 50 (FIG. 5) is made of a metal such as tungsten, copper, platinum, or gold as an example. Each of the plurality of probes 50 has a cylindrical shape as an example. One end portion of the probe 50 is a contact surface 50c that contacts the terminal _T A through T _D of strain gauge _{SG mn} during measurement.

The contact surface 50c has a circular shape as an example. The diameter of the contact surface 50c can be, for example, about 0.1 mm to 1.2 mm. The surface roughness (maximum height Rz) of the contact surface 50c is preferably 3 μm ≦ Rz ≦ 8 μm. As a result, variation in the measured value is suppressed, and damage to the strain gauge during measurement is prevented. The reason will be described later. In the present specification and the present invention, "maximum height Rz" means the maximum height Rz defined and measured in accordance with JIS B 0601-2001.

Each of the plurality of probes 50 is inserted into the plurality of holding holes 41h of the jig 41 and arranged in a matrix. As shown in FIG. 2, each of the plurality of probes 50 is housed inside the holding hole 41h with the contact surface 50c facing downward and penetrating the jig 41 up and down.

As shown in FIG. 4, the jig 41 holds 80 probes 50 and arranges them in a matrix of 5 rows × 16 columns. Further, assuming that the four probes 50 arranged in the width direction are regarded as the probe set 50S (FIG. 4), the jig 41 holds the 20 probe sets 50S and arranges them in a matrix of 5 rows × 4 columns. Four probes 50 of each probe set 50S is the time of measurement, in contact with the four terminals _T A through T _D of the strain gauge _{SG mn} (details below).

The measurement execution unit 60 is a portion that measures the input resistance, output resistance, and output voltage of _{the strain gauge SG mn using the probe 50.} The measurement execution unit 60 is arranged inside the base 10 and is connected to each of the plurality of probes 50 by a wiring (not shown).

The measurement execution unit 60 includes a power supply 61, a digital multimeter (DMM) 62, and a relay circuit (measurement circuit) 63. The power supply 61 supplies an input voltage for measurement. The DMM 62 measures the input resistance, output resistance, output voltage, etc. of the strain gauge SG _mn. The relay circuit 63 is a circuit that connects each of the power supply 61, the DMM 62, and the plurality of probes 50. The configuration of the relay circuit 63 can be switched (changeable) according to the measurement content.

The marking mechanism 70 is a mechanism for marking a predetermined strain gauge SG _mn based on the result of measurement performed by the measurement executing unit 60. The marking mechanism 70 is arranged on the work installation side of the jig 41 in the slide direction.

The marking mechanism 70 includes a pen 71 having a pen tip 71t and a pen holding mechanism 72 that holds the pen 71 so as to be movable in the width direction and the vertical direction. The marking mechanism 70 is not limited to the one using a pen, and may be one that marks with a needle or a cutter.

The pen 71 is held by the pen holding mechanism 72 with the pen tip 71t facing downward. The pen holding mechanism 72 may be any mechanism capable of moving the pen 71 in the width direction and the vertical direction. An example of the pen holding mechanism 72 is an air slider.

The control unit CONT is housed inside the base 10. The control device CONT is connected to the drive mechanism 20, the measurement execution unit 60, and the marking mechanism 70, and can communicate with these.

[Measuring method]
As shown in the flowchart of FIG. 6, the measurement of the electrical characteristics (input resistance, output resistance, output voltage, etc.) of _{the strain gauge SG mn} using the probe 50 and the measuring device 100 is performed in the work installation process S1, the measurement process S2, and the marking. The step S3 is included.

In the work installation step S1, the strain gauge strip 900, which is the object to be measured, is installed on the table 30 of the measuring device 100. Specifically, the work installation step S1 is performed as follows, for example.

First, the table 30 is moved to the position farthest from the jig 41 (FIG. 7 (a), hereinafter referred to as “work installation position”), and the strain gauge strip 900 is installed on the table 30. At this time, by arranging the alignment pins 41p at the four corners of the table 30 inside the alignment holes 910h at the four corners of the gauge base 910, the strain gauge strip 900 can be easily aligned with the table 30.

Next, the strain gauge strip 900 is sucked by sucking air through the intake hole 30h of the table 30, and the strain gauge strip 900 is fixed to the table 30. In addition to, or in place of, suction through the intake hole 30h, a weight can also be used. Specifically, for example, a weight having a resin attached to the bottom surface of a frame-shaped metal frame may be placed on the peripheral edge of the strain gauge strip 900, and the peripheral edge of the strain gauge strip 900 may be pressed from above.

By adhering the strain gauge strip 900 on the upper surface 30u of the table 30, by gauge strip 900 strain in other words it is held such that a flat, terminal T _A ~ of the probes 50 a plurality of strain gauges SG _mn It can be brought into contact with the T _{D in a uniform state.} As a result, the accuracy of measurement in the measurement step S2 can be further improved.

_{In the measurement step S2, the electrical characteristics of each of the strain gauge SG mn} included in the strain gauge strip 900 are mainly performed by using the plurality of probes 50 and the measurement execution unit 60. Specifically, the measurement step S2 is performed as follows, for example.

First, the table 30 is slid to a position directly below the jig 41 (FIG. 7 (b), hereinafter referred to as a “standby position”). After that, the table 30 is raised to a position where the contact surfaces 50c of the plurality of probes 50 come into contact with the strain gauge strip 900 (FIG. 7 (c), hereinafter referred to as “measurement position”) and stopped.

With the table 30 stopped at the measurement position, each of the plurality of probes 50 contacts each of _{the plurality of strain gauges SG mns of the strain gauge strip 900.} Specifically, four probes 50 included in each probe set 50S is in contact to terminals _T A through T _D of each of the strain gauges _{SG mn.} The contact pressure (probe pushing pressure) can be, for example, about 60 to about 80 gf (about 850 to about 1150 gf / mm ² ) per probe 50.

Next, the measurement execution unit 60 measures the input resistance, the output resistance, and the output voltage for each of the _{strain gauges SG mn.} The specific measurement method is as follows as an example.

First, the measurement execution unit 60 measures the strain gauge SG ₁₁ by the following steps.

(1) using the relay circuit 63, power supply 61, the probe 50 in contact with the terminal _{T A,} constitute the terminal _{T A,} terminal _{T C,} the closed circuit connecting the probe 50, and DMM62 contacts the terminal _{T C,} strain Measure the input resistance of the gauge SG _11.
(2) using the relay circuit 63, power supply 61, constitute a probe 50 in contact with the terminal _{T B,} the terminal _{T B,} terminal _{T D,} the closed circuit connecting the probe 50, DMM62 in contact with the terminal _{T D,} strain gauge Measure the output resistance of SG _11.
(3) using the relay circuit 63 and the probe 50, and connect the power unit 61 terminal _T A, the _{T C,} connects the DMM62 terminal _T B, the _{T D.} In a state that provides an input voltage _{V in} to the strain gauge _{SG 11} by the power supply unit 61 measures the output voltage _{V out} of _the gauge _{SG 11} strain in DMM62 (Measurement of zero balance).

The measurement execution unit 60 sends the measured input resistance, output resistance, and output voltage of _{the strain gauge SG 11 to the control unit CONT.}

After the measurement of the strain gauge SG ₁₁ is completed, the measurement execution unit 60 switches the relay circuit 63 to perform the same measurement on _{the strain gauge SG 12.} The measurement execution unit 60 performs the same measurement in order for all _{20 strain gauges SG mn.} The input resistance, output resistance, and output voltage of each of the measured strain gauges SG _{mn are sent to the control unit CONT.}

In the marking step S3, the marking mechanism 70 marks a predetermined strain gauge in the _{strain gauge SG mn according to the measurement result in the measuring step S2.} Specifically, the marking step is performed as follows, for example.

First, the table 30 is lowered from the measurement position to the standby position and slid to a position directly below the marking mechanism 70 (FIG. 7 (d), hereinafter referred to as “marking position”).

On the other hand, the control unit CONT compares each measured value (input resistance, output resistance, output voltage) of _{the strain gauge SG mn} received from the measurement executing unit 60 in the measurement step S2 with a predetermined reference value, and each measured value. Determines if is within the permissible tolerance.

When the measured value is out of the allowable tolerance in any of the plurality of strain gauges SG _{mn, the control unit CONT arranges the strain gauge directly under the pen 71.} The alignment in the slide direction is performed by moving the table 30, and the alignment in the width direction is performed by moving the pen holding mechanism 72.

Next, the control unit CONT lowers the pen 71 using the pen holding mechanism 72, and marks the strain gauge determined that the measured value is not within the allowable tolerance.

The control unit CONT returns the table 30 to the work installation position after marking all the strain gauges whose measured values are not within the allowable tolerance.

After that, the measured strain gauge strip 900 is removed from the table 30, and the work installation step S1, the measurement step S2, and the marking step S3 are repeated.

[Dressing method]
Here, a dressing method (roughening method) in which the contact surface 50c of the probe 50 is dressed (roughened) to give a desired surface roughness to the contact surface 50c will be described.

When the strain gauge strip 900 is continuously measured using the measuring device 100, it is observed that the surface roughness of the contact surface 50c is reduced (the maximum height Rz is reduced) in the probe 50 of the measuring device 100. Has been done. This is pressed by the terminal T _A through T _D of the contact surface 50c contacts the time of measurement, in order to smooth the contact surface 50c is caused.

Therefore, the contact surface 50c is dressed every measurement of a predetermined number of strain gauge strips 900 or every predetermined time (periodically), and the maximum height Rz of the contact surface 50c is in the range of 3 μm ≦ Rz ≦ 8 μm. It is preferable to return to.

Specifically, dressing is performed as follows, for example.

First, the table 30 is moved to the work installation position, and sandpaper (roughening member) having a rectangular shape in a plan view is installed on the table 30. Alignment holes may be provided at the four corners of the sandpaper so that alignment using the alignment pin 30p is possible. The sandpaper may have the same dimensions and thickness as the strain gauge strip 900.

Next, the table 30 on which the sandpaper is installed is moved to the standby position and raised. As a result, the sandpaper is pressed against the contact surface 50c at a predetermined pressure (for example, about 60 gf to about 80 gf per probe), the roughness of the sandpaper is transferred to the contact surface 50c, and the contact surface 50c Dressing is done. The sandpaper may be pressed against the contact surface 50c a plurality of times by repeating the ascent and descent of the table 30 a plurality of times.

After that, the table 30 is returned to the work installation position, the sandpaper is replaced with a clean cloth (cleaning cloth), and the table 30 is pressed against the contact surface 50c once or a plurality of times in the same manner as the sandpaper. The clean cloth may be impregnated with ethanol or the like.

After the cleaning is completed, the table 30 is returned to the work installation position, the clean cloth is replaced with the next object to be measured (strain gauge strip 900), and the measurement of the electrical characteristics of the _{strain gauge SG mn is restarted.}

[Significance of setting the surface roughness (maximum height Rz) to 3 μm ≦ Rz ≦ 8 μm]
Next, in the probe 50 of the present embodiment, the reason why it is preferable that the maximum height Rz of the contact surface 50c is 3 μm or more and 8 μm or less will be described.

First, the reason why it is preferable to set the maximum height Rz of the contact surface 50c to 3 μm or more is as follows.

The inventor of the present invention has diligently studied a method of suppressing variations in measured values that occur when measuring the electrical characteristics of a strain gauge using a probe, and the surface roughness (maximum height Rz) of the contact surface of the probe. I paid attention to. According to the findings of the inventor of the present invention, the variation in the measured values is such that the contact state between the contact surface of the probe and the terminal of the strain gauge is slightly different for each measurement, and thus between the contact surface and the terminal. This is due to the change in the contact resistance that occurs. Further, the inventor of the present invention can stabilize the contact state between the contact surface of the probe and the terminal of the strain gauge by setting the maximum height Rz of the contact surface of the probe to 3 μm or more, and can change the contact resistance. It was found that it can be sufficiently suppressed.

The inventor of the present invention conducted the following tests based on the above findings.

First, the contact surfaces of the same type of probes are treated with files of different counts, and the probes of Examples 1 to 11 having a maximum height Rz of the contact surface of about 3 μm or more and the maximum height Rz of the contact surface are about. Four probes of Comparative Examples 1 to 3 having a size of less than 3 μm were prepared. In addition, one sample strain gauge was prepared.

The probes of Examples 1 to 11 and the probes of Comparative Examples 1 to 3 are both formed of tungsten, and the contact surface is circular with a diameter of 0.3 mm.

The maximum height Rz of each contact surface of the probes of Examples 1 to 11 and the probes of Comparative Examples 1 to 3 is as shown in FIG.

The maximum height Rz of the probes of Examples 1 to 11 and the probes of Comparative Examples 1 to 3 was measured according to JISB 0601-2001.

Further, the sample strain gauge was assumed to have the structure shown in FIG. 1 (b). The material of the wiring layer of the sample strain gauge was copper-nickel alloy, and the thickness was about 5 μm. The material of the gauge base of the sample strain gauge was PI (polyimide), and the thickness was about 25 μm.

Next, the probe of the first embodiment is held by the jig 41 of the measuring device 100 so as to form one probe set 50S, and the input resistance and the output resistance of the sample strain gauge are measured by using the measuring device 100. Each was done 3 times. In the three measurements, the probe pressing pressure was constant (70 gf per probe). Then, the variation (difference between the maximum value and the minimum value) of the three measured values obtained by the three measurements for each of the input resistance and the output resistance was determined.

Further, for each probe of Examples 2 to 11 and each probe of Comparative Examples 1 to 3, the input resistance and output resistance of the sample strain gauge were measured three times each in the same manner as in Example 1, and the input resistance was determined. The variability of the three measured values was determined for each of the output resistors. In the measurement of each Example and each Comparative Example, a common sample strain gauge was used.

The measurement results are shown in FIG. In FIG. 8, the variation between the three measured values for both the input resistance and the output resistance is less than ± 1Ω, which is indicated by ◯. On the other hand, the variation between the three measured values for both the input resistance and the output resistance is ± 1Ω or more, which is indicated by ×. As shown in FIG. 8, in Examples 1 to 11 in which the maximum height Rz is 3 μm or more, the variation of the measured values is within ± 1 Ω, and in Comparative Examples 1 to 3 in which the maximum height Rz is less than 3 μm. The variation of the measured value is ± 1Ω or more.

According to the findings of the inventor of the present invention, one of the reasons why the variation in the measured values becomes large when the maximum height Rz of the contact surface of the probe is small is as follows.

FIG. 9A shows a simplified cross-sectional view of the contact surface CS1 of the probe, and FIG. 10A shows a simplified cross-sectional view of the contact surface CS2 of the probe. The maximum height Rz of the contact surface CS1 is smaller than the maximum height Rz of the contact surface CS2. In FIGS. 9 (a) and 10 (a), the dotted lines L ₁₁ and L ₂₁ indicate the positions of the surfaces of the terminals of the strain gauge. In the portion where the contact surfaces CS1 and CS2 are located below the dotted lines L ₁₁ and L ₂₁ , the contact surfaces CS1 and CS2 push down the surface of the terminal and are buried inside the terminal. That is, the contact surfaces CS1 and CS2 are engaged with the surface of the terminal.

As shown in FIGS. 9 (b) and 10 (b), when the probe is tilted with respect to the terminal by a _{minute angle θ 0 and} the surface of the terminal moves to the position indicated _{by the dotted lines L 12} and L _{22, the contact surface CS1} , The width of the contact surface between the CS2 and the surface of the terminal changes by an amount corresponding to the length of the thick line shown in FIGS. 9 (b) and 10 (b). As can be read from FIGS. 9 (b) and 10 (b), when the angle with respect to the terminal of the probe changes, the contact area changes significantly on the contact surface CS1 having a small maximum height Rz, and the contact resistance also changes. It tends to be big.

Further, in the contact surface CS1 having a small maximum height Rz, when the probe is _{tilted beyond the minute angle θ 13} with respect to the terminal, a part of the contact surface CS1 is removed from the surface of the terminal at the position indicated _{by the dotted line L 13.} It will be separated and the contact area will be smaller. Even on the contact surface CS2 having a large maximum height Rz, when the probe is _{tilted beyond the minute angle θ 23} with respect to the terminal, a part of the contact surface CS2 is completely removed from the surface of the terminal at the position indicated _{by the dotted line L 23.} Although they are separated, the angle θ ₂₃ is larger than the angle θ _13.

In this way, when the angle of the probe with respect to the terminal changes, the contact area of the contact surface CS1 having a relatively small maximum height Rz changes more significantly than that of the contact surface CS2 having a relatively large maximum height Rz. , Contact resistance tends to change more.

Further, as shown in FIGS. 9 (c) and 10 (c), when the probe _{moves away from the terminal by a minute distance d 0} and the surface of the terminal _{moves to the position indicated by the dotted lines L 14} and L ₂₄ , the contact surfaces CS1 and The contact surface between the CS2 and the surface of the terminal changes by an amount corresponding to the length of the thick line shown in FIGS. 9 (c) and 10 (c). As can be read from FIGS. 9 (c) and 10 (c), even when the distance to the terminal of the probe changes, the contact area changes significantly and the contact resistance changes significantly on the contact surface CS1 having a small maximum height Rz. It tends to be.

In this way, when the maximum height Rz of the contact surface of the probe is small, the contact area according to the change in the contact state with respect to the terminal, and thus the amount of change in the contact resistance tends to be large, and the variation in the measured value tends to be large. be.

The terminal of the strain gauge made of copper-nickel alloy usually has an oxide film of about 3 μm or thinner. According to the findings of the inventor of the present invention, when the maximum height of the contact surface is larger than 3 μm, the convex portion of the contact surface (the portion forming a micro peak in the cross-sectional view of the contact surface) forms an oxide film. Breakthrough, more areas of the contact surface come into direct contact with the terminals of the strain gauge. In this way, even if more regions of the contact surface are brought into direct contact with the terminals without passing through the oxide film, the contact state is stabilized and the amount of change in contact resistance in response to changes in the contact state is suppressed. Will be done.

From the above, the maximum height Rz of the contact surface 50c is preferably 3 μm or more. As a result, variations in measured values can be satisfactorily suppressed.

Next, the reason why the maximum height Rz of the contact surface 50c is preferably 8 μm or less is as follows.

Strain gauges generally have a structure in which a conductive wiring layer including a resistor is formed on a gauge base formed of a flexible dielectric, and is a conductor such as metal when used. Attach the gauge base to the strain. That is, the gauge base functions to insulate the wiring from the strain-causing body.

Here, in order to satisfactorily measure the strain using the strain gauge, it is necessary to expand and contract the resistor of the wiring layer satisfactorily according to the expansion and contraction of the strain-causing body. Therefore, it is not realistic to thicken the gauge base only in consideration of insulation.

In consideration of the above points, the strain gauge generally has a wiring layer thickness of about 3 to 5 μm and a gauge base thickness of about 25 μm.

According to the knowledge of the inventor of the present invention, when the maximum height of the contact surface of the probe is 8 μm or less, when the contact surface of the probe is brought into contact with the terminal of the strain gauge, the convex portion of the contact surface of the probe forms the gauge base. Does not hurt excessively. Therefore, damage to the gauge base prevents the insulation performance of the gauge base from deteriorating and the performance of the strain gauge from deteriorating.

From the above, the maximum height Rz of the contact surface 50c is preferably 8 μm or less.

The effects of the probe 50, the measuring device 100, and the measuring method of the present embodiment are summarized below.

Probe 50 of the present embodiment, the contact surface roughness of the contact with the terminal _T A through T _D strain gauges _{SG mn} to be measured (maximum height Rz) of is 3μm or more. Therefore, _{the change in the contact resistance according to the change in the contact state with respect to the terminals T A to} T _D is small, and it is possible to suppress the variation in the measured value when a plurality of measurements are performed.

Further, the terminal T _A through T _D strain gauges SG _mn, since generally thin oxide film than this or is about 3μm is formed, the maximum height of the contact surface by a least 3μm , breaking through the oxide film, the contact surface 50c and the terminal _T a through T _D can be good contact. As a result, it is possible to suppress the amount of change in the contact resistance according to the change in the contact state and suppress the variation in the measured value.

In the probe 50 of the present embodiment, the surface roughness (maximum height Rz) of the contact surface 50c is 8 μm or less. Accordingly, damage to the gauge base 910 is prevented by contact between the contact surface 50c and the terminal _T A through T _D. Further, also suppressed to mark contact with the terminal _T A through T _D remains.

That probe 50 of the present embodiment, by surface roughness of the contact surface 50c (the maximum height Rz) not less than 3 [mu] m, the measurements to stabilize the contact state of terminals T _A through T _D of the contact surface 50c By suppressing the variation and setting the surface roughness (maximum height Rz) of the contact surface 50c to 8 μm or less, it is possible to prevent damage to the _{strain gauge SG mn that may occur during measurement.}

Since the measuring device 100 of the present embodiment includes the probe 50 in which the variation in the measured values is suppressed (that is, the measured values are highly reliable), the reliability is only one measurement per _{strain gauge SG mn.} High measurement value can be obtained. Therefore, the measurement time can be greatly shortened as compared with the conventional measuring device which needs to improve the reliability of the measured value by performing a plurality of measurements on one strain gauge and obtaining the average value. ..

Since the measuring method of the present embodiment uses the measuring device 100, the same effect as that of the measuring device 100 is produced. In addition, the contact surface 50c of the probe 50 is dressed (roughened) at a predetermined timing to maintain the maximum height Rz of the contact surface 50c at 3 μm or more and 8 μm or less, so that highly reliable measurement can be performed for a long period of time. It can be done continuously.

<Modification example>
The following modifications can also be used in the probe 50, the measuring device 100, and the measuring method of the above embodiment.

The probe 50 of the above embodiment may be used independently of the measuring device 100. Specifically, for example, by contacting a probe to the terminal T _A through T _D gauge SG _mn strain worker operates the probe 50 may be measuring the electrical characteristic of the strain gauge SG _mn.

The probe 50 of the above embodiment has a cylindrical shape, and the contact surface 50c is circular, but the present invention is not limited to this. The shapes of the probe 50 and the contact surface 50c are arbitrary. For example, the shape of the contact surface 50c may be a square or a polygon.

Further, the object to be measured is not limited to the _{strain gauge SG mn.} Specifically, for example, the probe 50 can be used in measuring the electrical characteristics (circuit resistance, etc.) of PCBA (printed circuit board assembly). The terminals of the PCBA are also generally formed of a copper-nickel alloy, and an oxide film of about 3 μm or thinner is formed.

The object to be measured may be any other electrical component, electronic component, or the like whose electrical characteristics need to be measured.

In the measuring device 100 of the above embodiment, the jig 41 is formed with 80 plurality of holding holes 41h (5 rows in the width direction x 16 columns in the slide direction), but the present invention is not limited to this. The number and arrangement of the holding holes 41h of the jig 41, that is, the number and arrangement of the probes 50 held by the jig 41 can be arbitrarily set according to the design of the measuring device 100.

The measuring device 100 of the above embodiment can be appropriately modified to be a measuring device for measuring any electrical component, electronic component, or the like that needs to measure electrical characteristics. Specifically, for example, the configuration of the table 30 and the configuration of the jig 41 can be modified.

As long as the features of the present invention are maintained, the present invention is not limited to the above-described embodiment, and other modes considered within the scope of the technical idea of the present invention are also included within the scope of the present invention. ..

10 base, 20 drive mechanism, 30 table, 40 probe holding mechanism, 50 probe, 60, measurement execution unit, 70 marking mechanism, 100 measuring device, 900 strain gauge strip, SG _mn strain gauge

Claims (9)

A probe for measuring the electrical characteristics of an object to be measured.
It has a contact surface that comes into contact with the object to be measured, and has a contact surface.
A probe having a maximum height Rz of the contact surface of 3 μm or more and 8 μm or less. The probe according to claim 1, wherein an oxide film is formed on a portion of the object to be measured that comes into contact with the contact surface. The probe according to claim 1 or 2, wherein the object to be measured is a strain gauge. A measuring device for measuring the electrical characteristics of an object to be measured.
The probe according to any one of claims 1 to 3 and
A jig that holds the probe and
A measuring device including a measuring object moving mechanism that holds the measured object and brings the measured object into contact with the contact surface of the probe. The object moving mechanism brings the object to be measured into contact with the contact surface of the probe so that the contact pressure between the contact surface of the probe and the object to be measured is 850 to 1150 gf / mm ^2. The measuring device according to claim 4. 4. measuring device. The jig is configured to hold a plurality of the probes in a matrix, and the object moving mechanism so as to bring the plurality of probes held in a matrix into contact with the object to be measured at the same time. The measuring device according to any one of claims 4 to 6, which is configured. It is a measuring method for measuring the electrical characteristics of an object to be measured.
To measure the electrical characteristics of the object to be measured by bringing the contact surface of the probe according to any one of claims 1 to 3 into contact with the object to be measured.
A measuring method including roughening the contact surface. The measuring method according to claim 8, wherein the roughening treatment is performed every time a predetermined number of the objects to be measured are measured, or every time a predetermined time elapses.

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