JP2004053413A - Measuring device and measuring method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device and a measuring method using it which can accurately measure the diameter of the inside part of a small hole even with a very small blind hole not penetrating an object being measured, groove width, roundness, surface roughness, etc. <P>SOLUTION: The device comprises a rod-shape microprobe 2 where styluses 8a and 8b contacting internal surface 1b of a pit being measured 1a of the object being measured 1 to tip section are provided, strain gauges 8a and 9b directly placed on the shell surface of the microprobe 2, a strain amplifier for detecting the variation of electric resitrance value of the strain gauges 8a and 8b, and a computer 5 executing various operation based on the detection results of the strain amplifier. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a measuring device capable of measuring a diameter of an inner portion of a micro hole, a width of a groove, a roundness, a surface roughness, and the like, and a measuring method using the same.
[0002]
[Prior art]
A vibro-scanning method using electrical contact detection is known as one of the methods for measuring the internal shape of a minute hole. In the vibro-scanning method, electricity is supplied to an object to be measured, and a probe formed of a conductor is inserted into a minute hole of the object to be measured. When the probe comes into contact with the inner surface of the minute hole, the probe and the object to be measured conduct, and electricity flows. Therefore, measurement is performed by detecting an electric signal at that time.
[0003]
However, in the vibro-scanning method, measurement cannot be performed when the object to be measured is not a conductor. As a method for measuring the minute hole of the non-conductive (insulating) object to be measured, two conductor probes are inserted into the minute hole of the object to be measured, and the two conductor probes are contacted with each other. A method of measuring by detecting continuity is known.
[0004]
Further, as described in JP-A-9-31015, light is projected from one of the minute holes of the object to be measured, and a reflection image from a wall surface (measurement surface) of the minute hole is observed. There is known an optical length measuring device for measuring the inner diameter of a lens with high accuracy.
[0005]
[Problems to be solved by the invention]
In a measurement method using electrical contact detection, such as a vibro-scanning method, a slight spark is generated when an object to be measured contacts a probe. Therefore, an electric force acts on the probe due to the generated spark to cause a measurement error, and thus an inaccurate measurement result may be output.
[0006]
In the measurement method using two conductor probes, it is necessary to insert two probes into a minute hole of an object to be measured. Therefore, even if the outer diameter of the probe is reduced, the minimum measurable inner diameter is limited to twice or more the outer diameter of the probe. Conventionally, the minimum inner diameter that can be measured by the electrical contact detection is about 100 μm.
[0007]
In an optical length measuring device, it is necessary to pass the light incident from one of the micro holes to the opposite side of the object to be measured, so it is possible to measure unless the hole to be measured penetrates the object to be measured. Can not. Also, measurement cannot be performed when there is a step or the like in the middle of the hole that impedes the passage of light.
[0008]
Therefore, in the present invention, even for a very small blind hole that does not penetrate the measured object, the diameter of the inner part of the minute hole, the width of the groove, the roundness, the surface roughness, and the like can be accurately determined. It is an object of the present invention to provide a measuring device capable of measuring and a measuring method using the same.
[0009]
[Means for Solving the Problems]
The measuring device of the present invention includes a rod-shaped probe provided with a contact at the tip thereof for contacting an inner wall surface of a measured hole of an object to be measured, a strain gauge provided directly on a body surface of the probe, and an electric resistance of the strain gauge. Detecting means for detecting a change in the value.
[0010]
According to the present invention, a change in the electric resistance value of a strain gauge provided directly on the body surface of the probe is detected in accordance with the displacement of the contact provided at the tip of the probe, and the contact of the contact based on the detection result is detected. From the displacement, the diameter of the inside portion of the measured hole of the measured object, the width of the groove, the roundness, the surface roughness, and the like can be calculated.
[0011]
Here, it is desirable that the contact point contact the inner wall surface. This is because the point of contact between the contact and the inner wall surface becomes clearer by making the shape of the contact point conical, pyramidal, or spherical so as to make point contact with the inner wall surface of the hole to be measured.
[0012]
It is desirable to provide a pair of strain gauges on a surface on the same side as the contactor and on a surface symmetrical with respect to the axis of the probe. As a result, the displacement of the contact is converted into both elongation deformation and contraction deformation of a pair of strain gauges provided on a surface symmetrical to each other with respect to the axis of the probe. Is detected as a larger change in.
[0013]
In the method for measuring the roundness of a hole to be measured using the measuring device of the present invention, the contact of the probe is brought into contact with the inner wall surface of the hole to be measured, and the object to be measured is rotated around the center line of the hole to be measured. The roundness of the hole to be measured is calculated based on the detection result of the detecting means at the time of making the hole.
[0014]
According to this measuring method, since the deviation of the measured hole from the perfect circle is detected as the displacement of the contact when the measured object is rotated, the roundness of the measured hole is calculated based on this. Is done.
[0015]
In the method for measuring the surface roughness of a hole to be measured using the measuring device of the present invention, the contact of the probe is brought into contact with the inner wall surface of the hole to be measured, and the probe is moved at a constant speed in the axial direction of the hole to be measured. The surface roughness of the hole to be measured is calculated based on the detection result of the detecting means at that time.
[0016]
According to this measuring method, the unevenness of the inner wall surface of the hole to be measured is detected as the displacement of the contact when the probe is moved at a constant speed in the axial direction of the hole to be measured. The surface roughness of the hole is calculated.
[0017]
In the measuring device of the present invention, the contact is provided in a pair on a surface on the same side as the strain gauge and on a surface symmetrical to this surface with respect to the probe axis. The inner diameter of the measurement hole can be measured.
[0018]
The method for measuring the inner diameter of the hole to be measured includes a first step of moving the probe toward the wall surface of the hole to be measured, and a position of a contact point when one contact of the probe contacts the wall surface of the hole to be measured. A second step of specifying based on the detection result of the detecting means, a third step of moving the probe in the direction of the other contact, and a position of a contact point when the contact comes into contact with a wall surface of the hole to be measured And a fifth step of calculating the distance between the contact points based on the positions of the two contact points specified by the second step and the fourth step, respectively. The measurement is performed at a plurality of measurement positions having different coordinates in the direction perpendicular to the movement directions of the first and second steps, and the maximum value of the distance between the contact points at each measurement position is determined as the inner diameter of the hole to be measured. It is.
[0019]
According to this measuring method, the position of the contact point when one of the contacts provided in a pair on the symmetrical surface is in contact with the wall surface of the hole to be measured, and the other contact is on the wall surface of the hole to be measured. The portion where the distance (the length of the chord) between the contact point and the position of the contact point is maximum is measured as the inner diameter of the measured hole.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic configuration diagram of a measuring device according to an embodiment of the present invention.
In FIG. 1, the measuring apparatus according to the present embodiment includes an object 1 to be measured and a microprobe 2 for measurement inserted into a hole 1a of the object 1 to be measured. In addition, the measuring apparatus includes an X table 3a and a Y table 3b that can move in the x direction (vertical direction with respect to the drawing) and the y direction (left and right direction in FIG. Prepare. The DUT 1 is mounted on a C table 3c which can be rotated on an X table 3a as an ultra-precise moving means of the DUT 1.
[0021]
The microprobe 2 is fixed to a Z table 3d that can move in the z direction (the vertical direction in FIG. 1) as an ultra-precision moving means. The Z table 3d is provided with a CCD camera 4 for imaging the DUT 1 on the C table 3c. The output of the CCD camera 4 is input to a computer 5. The operations of the X table 3a, the Y table 3b, the C table 3c, and the Z table 3d are controlled by the computer 5, respectively.
[0022]
FIG. 2A is a side view of the microprobe 2 and FIG. 2B is a front view.
In the present embodiment, the insertion portion 2a of the microprobe 2 into the measured hole 1a is a rod-shaped member having a square cross section with a side length of 14 μm. Further, on both side surfaces of the distal end portion 2b, a pair of diamond styluses 7a and 7b are provided symmetrically as contacts for contacting the inner wall surface of the hole to be measured 1a. The microprobe 2 is not limited to a square cross section, but may have a rectangular cross section or an elliptical cross section.
[0023]
3A is an enlarged view of a portion A in FIG. 2 as viewed from the right side, FIG. 3B is a view of FIG. 3A as viewed from below, and FIG. 4 is an enlarged view of the strain gauge.
The base 2c of the insertion portion 2a of the microprobe 2 is provided with a pair of strain gauges 8a, 8b on both side surfaces on the same side as the styluses 7a, 7b. Each of the strain gauges 8a and 8b is a 1 μm-wide copper pattern formed directly on the surface of the body of the microprobe 2 using a lithography technique. The strain gauges 8a and 8b are connected to the computer 5 via a strain amplifier 6. The microprobe 2 uses zirconia (zirconium oxide), which is an insulator. When a member that is not an insulator is used, a copper pattern is applied after coating with an insulator.
[0024]
5A is an enlarged view of a portion B in FIG. 2, and FIG. 5B is a view of FIG.
The styluses 7a and 7b shown in FIG. 5 are conical with a bottom surface having a diameter of 10 μm, and the apex angle is 90 °. The width between both vertices is 24 μm. The styluses 7a and 7b having such a shape make point contact with the inner wall surface 1b of the measured hole 1a. In order to measure the inner diameter and the like by the present measuring device, it is sufficient that the microprobe 2 can be inserted into the measured hole 1a. Therefore, the minimum inner diameter of the measured hole 1a that can be measured by the present measuring device is about 30 μm.
[0025]
FIG. 6 shows another example of a stylus.
The styluses 9a and 9b shown in FIG. 6 are square pyramids having a bottom surface width of 10 μm, and the apex angle is 90 °. In addition, in the case of the styluses 9a and 9b, since the tip 2b of the microprobe 2 is formed to be one step thinner to a square cross section with a width of 10 μm, the width between both vertices of the styluses 9a and 9b is 20 μm. The shape of the stylus may be hemispherical. In short, if the stylus and the inner wall surface 1b are in point contact with the inner wall surface 1b of the hole to be measured 1b, the contact area between the stylus and the inner wall surface 1b is narrowed, so that the contact point becomes clearer and high-precision measurement can be performed. .
[0026]
Here, the generation principle of the output signal in the microprobe 2 will be described with reference to FIGS. FIG. 7 is a schematic diagram showing a state in which the microprobe 2 is in contact with the inner wall surface 1b of the hole to be measured 1a, and FIG. 8 is a circuit diagram of the distortion amplifier 6.
[0027]
In FIG. 7, when the upper stylus 7a of the microprobe 2 contacts the inner wall surface 1b of the hole to be measured 1a, a tensile strain is generated on the strain gauge 8a (R ₁ ) on the same side as the stylus 7a, while A compressive strain is generated in the strain gauge 8b (R ₂ ) on the surface. In strain amplifier 6, by incorporating these two strain gauges 8a, 8b and _(R 1, _{R 2)} to the Wheatstone bridge shown in FIG. 8, for detecting a change in the strain gauges 8a, the electric resistance value of 8b.
[0028]
In FIG. 8, R ₃ and R ₄ are fixed resistors. In a state where the stylus 7a of the microprobe 2 is not in contact with the inner wall surface 1b of the hole 1a to be measured (balanced state), R ₁ × R ₄ = R ₂ × R ₃ and the output signal at this time G is zero. However, the stylus 7a is in contact with the inner wall surface 1b, the strain gauges 8a, 8b when the change in resistance (R 1, _{R 2)} occurs collapses this balance, resulting in a voltage proportional to the strain amount is outputted. This output signal (voltage) G (V) is input to the computer 5.
[0029]
Hereinafter, various measuring methods using the measuring device having the above configuration will be described.
(Inner diameter measurement)
FIG. 9 is a diagram of the measured hole 1a as viewed from the z direction, and FIG. 10 is a cross-sectional view taken along the line CC of FIG. The inner diameter measurement is performed according to the following procedure.
[0030]
Step 1: Image processing is performed by the computer 5 based on the image captured by the CCD camera 4, and the approximate position of the measured hole 1a is grasped.
Step 2: Based on the result of Step 1, move the X table 3a, the Y table 3b and the C table 3c to align the hole to be measured 1a immediately below the microprobe 2, and move the Z table 3d to move the hole to be measured to the hole 1a. Insert the microprobe 2.
[0031]
Step 3: By moving the Y table 3b, the microprobe 2 is moved in the y direction in the measured hole 1a, and the resistance of the strain gauges 8a, 8b when the stylus 7a contacts the inner wall surface 1b of the measured hole 1a. the Y table 3b stops signal change as a trigger, and stores the position of the stylus tip 7a at that time (y-coordinate y ₁₎ to the computer 5.
[0032]
Step 4: Similarly, the microprobe 2 is moved in the -y direction in the hole 1a to be measured by moving the Y table 3b in the opposite direction to that in step 3, and the stylus 7b contacts the inner wall surface 1b of the hole 1a to be measured. The Y table 3b is stopped by using the signal of the resistance change of the strain gauges 8a and 8b at this time as a trigger, and the position (y coordinate y ₂ ) of the tip of the stylus 7b at that time is stored in the computer 5.
[0033]
Step 5: The computer 5 calculates the distance between each of the contact points of the stylus _{7a, 7b (y 1 -y 2} ).
Step 6: Return the microprobe 2 to the position of (y ₁ + y ₂ ) / 2, move it by a small amount in the x direction, and repeat steps 1 to 5 to obtain the maximum value of (y ₁ −y ₂ ). Inside diameter.
[0034]
In this embodiment, when acquiring the positions of the tips of the styluses 7a and 7b, the position is corrected based on the graph shown in FIG. The horizontal axis of the graph in FIG. 11 is the amount of movement (μm) of the microprobe 2, and the vertical axis is the output signal (voltage V). In this measuring apparatus, when the output signal G reaches a preset threshold value, it is determined that the microprobe 2 has contacted the inner wall surface 1b of the measured hole 1a, and the position at that time is stored in the computer 5. . However, since the microprobe 2 actually moves while the output signal G increases from zero to the threshold value, the movement amount is corrected as the position correction amount.
[0035]
In addition to the above correction, it is also possible to perform a correction in consideration of the overtravel of the Y table 3b due to inertia, a delay of a signal, and the like in relation to the feed speed of the Y table 3b. These corrections can be performed by stopping the microprobe 2 when the output signal G reaches the threshold value in relation to the above-described threshold value. However, when the inertia is large or the moving speed is excessive, This is done to make 2 go too far.
[0036]
(Roundness measurement)
FIG. 12 is a diagram of the measured hole 1a as viewed from the z direction. The roundness measurement is performed according to the following procedure.
[0037]
Step 1: Image processing is performed by the computer 5 based on the image captured by the CCD camera 4, and the position of the measured hole 1a is accurately grasped.
Step 2: The X table 3a, the Y table 3b, and the C table 3c are moved based on the result of step 1 so that the hole to be measured 1a is directly below the microprobe 2. At this time, the center of the hole to be measured 1a coincides with the center of rotation of the C table 3c.
[0038]
Step 3: The microprobe 2 is inserted into the measured hole 1a by moving the Z table 3d, and the center axis of the microprobe 2 is aligned with the y-axis.
Step 4: By moving the Y table 3b, the microprobe 2 is moved in the y direction in the measured hole 1a, and the C table 3b is rotated while the stylus 7a is in light contact with the inner wall surface 1b of the measured hole 1a. Then, the output signal G (V) of the distortion amplifier 6 is recorded in the computer 5.
[0039]
FIG. 13 shows an example of an output signal of the distortion amplifier 6 recorded in the computer 5. The horizontal axis in FIG. 13 is the rotation angle of the C table 3b (the rotation angle of the DUT 1), and the vertical axis is the output signal G. The computer 5 calculates the roundness based on the result of FIG. Note that in calculating the roundness, it is necessary to clarify the relationship between the output signal G (V) and the displacement amount (μm) of the stylus 7a in advance.
[0040]
When measuring the roundness, the tip of the stylus 7a has a radius of r = 5 to 10 μm, and the tip of the stylus 7a is caught by the unevenness of the inner wall surface 1b of the hole 1a to be measured when the C table 3b rotates. It is desirable not to do so. This makes it easier for the tip of the stylus 7a to follow the irregularities of the inner wall surface 1b, and it is possible to more accurately measure the roundness.
[0041]
(Surface roughness measurement)
FIG. 14 is a view of the measured hole 1a as viewed from the z direction, and FIG. 15 is a sectional view taken along the y-axis of FIG. The surface roughness is measured according to the following procedure.
[0042]
Step 1: Image processing is performed by the computer 5 based on the image captured by the CCD camera 4, and the position of the measured hole 1a is accurately grasped.
Step 2: The X table 3a, the Y table 3b, and the C table 3c are moved based on the result of step 1 so that the hole to be measured 1a is directly below the microprobe 2.
[0043]
Step 3: The microprobe 2 is inserted into the measured hole 1a by moving the Z table 3d so that the contact point between the stylus 7a and the inner wall surface 1b of the measured hole 1a is on the y-axis.
Step 4: The Z table 3d is moved at a constant speed in the z direction, and the output signal G (V) of the distortion amplifier 6 at that time is recorded in the computer 5.
[0044]
FIG. 16 shows an example of an output signal of the distortion amplifier 6 recorded in the computer 5. The horizontal axis in FIG. 16 is the movement amount of the Z table 3d (the movement amount of the microprobe 2), and the vertical axis is the output signal G. The computer 5 calculates the surface roughness based on the result of FIG. In calculating the surface roughness, it is necessary to clarify the relationship between the output signal G (V) and the displacement amount (μm) of the stylus 7a in advance.
[0045]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0046]
(1) A rod-shaped probe provided with a contact at its tip for making contact with the inner wall surface of the hole to be measured, a strain gauge provided directly on the body surface of the probe, and a change in the electric resistance value of the strain gauge. With the provision of a detecting means for detecting, even if the measured hole is large enough to allow the contact at the tip of the probe to be inserted, if this probe is inserted, it will respond to the displacement of the contact provided at the tip. Thus, it is possible to measure the diameter, the width of the groove, the roundness, the surface roughness, and the like of the inner portion of the measured hole with high accuracy. Therefore, even a very small blind hole can be measured, and a smaller hole can be measured by making the probe and the contact small.
[0047]
(2) The point of contact between the contact and the inner wall surface is reduced by making the shape of the contact point conical, pyramidal, or spherical, and the contact range between the contact and the inner wall surface is narrowed. Highly accurate measurement can be performed.
[0048]
(3) Since the strain gauges are provided as a pair on a surface on the same side as the contact and on a surface symmetrical with respect to the axis of the probe, the displacement of the contact is Are converted into both extension and contraction deformations of a pair of strain gauges provided on a surface symmetrical to each other with respect to the axis of the axis, and detected as a larger change in the electrical resistance of the strain gauges. Accurate measurement can be performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a measuring device according to an embodiment of the present invention.
2A is a side view of a microprobe, and FIG. 2B is a front view.
3A is an enlarged view of a portion A in FIG. 2 as viewed from the right side, and FIG. 3B is a diagram of FIG. 2A as viewed from below.
FIG. 4 is an enlarged view of a strain gauge.
5A is an enlarged view of a portion B in FIG. 2, and FIG. 5B is a view of FIG.
6A and 6B are diagrams showing another example of the stylus, wherein FIG. 6A is an enlarged view of a portion B in FIG. 2, and FIG. 6B is a diagram of FIG.
FIG. 7 is a schematic diagram showing a contact state between a microprobe and an inner wall surface of a hole to be measured.
FIG. 8 is a circuit diagram of a distortion amplifier.
FIG. 9 is a diagram of a hole to be measured as viewed from the z direction when measuring the inner diameter.
FIG. 10 is a sectional view taken along the line CC of FIG. 9;
FIG. 11 is a diagram showing a graph of position correction.
FIG. 12 is a view of a hole to be measured as viewed from the z direction when measuring roundness.
FIG. 13 is a diagram illustrating an example of an output signal of a distortion amplifier when measuring roundness.
FIG. 14 is a diagram of a hole to be measured as viewed from the z direction when measuring the surface roughness.
15 is a cross-sectional view along the y-axis in FIG.
FIG. 16 is a diagram illustrating an example of an output signal of a distortion amplifier when measuring surface roughness.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measurement object 1a Measurement hole 1b Inner wall surface 2 Micro probe 2a Insertion part 2b Tip part 2c Root part 3a X table 3b Y table 3c C table 3d Z table 4 CCD camera 5 Computer 6 Strain amplifier 7a, 7b, 9a, 9b Stylus 8a, 8b Strain gauge

Claims (7)

A rod-shaped probe provided with a contact at the tip to contact the inner wall surface of the hole to be measured, a strain gauge provided directly on the body surface of the probe, and a change in the electric resistance value of the strain gauge detected A measuring device comprising: The measuring device according to claim 1, wherein the contact point contacts the inner wall surface. The measuring device according to claim 1, wherein the strain gauge is provided as a pair on a surface on the same side as the contactor and on a surface symmetrically positioned with respect to an axis of the probe. . 4. The contact according to claim 1, wherein the contact is provided in a pair on a surface on the same side as the strain gauge and on a surface symmetrically positioned with respect to an axis of the probe. 5. Measuring device. A rod-shaped probe provided with a contact at the tip that makes contact with the inner wall surface of the hole to be measured, a strain gauge provided directly on the body surface of the probe, and a change in the electrical resistance value of the strain gauge detected. A method of measuring the roundness of a hole to be measured using a measuring device having a detecting means,
The contact of the probe is brought into contact with the inner wall surface of the hole to be measured, and the measured object is measured based on a detection result of the detecting means when the object to be measured is rotated around a center line of the measured hole as a rotation axis. A measuring method for calculating the roundness of a hole. A rod-shaped probe provided with a contact at the tip that makes contact with the inner wall surface of the hole to be measured, a strain gauge provided directly on the body surface of the probe, and a change in the electrical resistance value of the strain gauge detected. A method for measuring the surface roughness of the hole to be measured using a measuring device having a detecting means to
The contact of the probe is brought into contact with the inner wall surface of the hole to be measured, and the probe is moved at a constant speed in the axial direction of the hole to be measured. A measuring method for calculating surface roughness. A rod-shaped probe provided with a contact at the tip that makes contact with the inner wall surface of the hole to be measured, a strain gauge provided directly on the body surface of the probe, and a change in the electrical resistance value of the strain gauge detected. Measuring device, wherein the contactor is provided in a pair on a surface on the same side as the strain gauge and a surface symmetrical to this surface with respect to the axis of the probe. A method for measuring the inner diameter of the measured hole used,
A first step of moving the probe toward a wall surface of the measured hole;
A second step of specifying a position of a contact point when one contact of the probe comes into contact with a wall surface of the hole to be measured based on a detection result of the detection unit;
A third step of moving the probe in the direction of the other contact;
A fourth step of specifying a position of a contact point when the contact is in contact with the wall surface of the hole to be measured based on a detection result of the detection unit;
A fifth step of calculating a distance between the contact points based on the positions of the two contact points specified in the second step and the fourth step,
Executing at a plurality of measurement positions having different coordinates in a direction perpendicular to the moving direction of the first and second steps;
A measurement method in which the maximum value of the distance between contact points at each measurement position is determined as the inner diameter of the measured hole.

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