JP2017156182A - Hole diameter measurement apparatus and measurement method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure a minute hole diameter being less than or equal to 1 mm, of a minute through-hole included in an object to be measured, without using a probe to be inserted into the hole.SOLUTION: A hole diameter measurement apparatus 100 is used for measuring a minute through-hole 71 which is included in an object 70 to be measured, and of which an inner diameter is less than or equal to 1 mm. The hole diameter measurement apparatus comprises: a white light source 12 having a continuous spectrum; a prism 14 for refracting white light emitted from the light source; placement means 60 on which the object to be measured is placed; positioning means 20 for positioning the light refracted by the prism, at a position near the hole of the object to be measured; light detection means 40 that is disposed at the back of the placement means, and which detects light passed through the hole; and computing means 50 for obtaining an upper limit wavelength λa' and a lower limit wavelength λb' of the light passed through the hole, on the basis of signals detected by the light detection means, and computing a hole diameter d using the obtained upper limit wavelength and lower limit wavelength.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hole diameter measuring apparatus and a measurement method using the same, and more particularly to a hole diameter measuring apparatus that measures a hole diameter using a spectral spectrum for a minute diameter through hole and a measurement method using the same.

  For accurate measurement of the hole diameter, contact and non-contact measurement using a probe and measurement using an optical or electronic microscope are known. For example, in the measurement of the minute inner diameter described in Patent Document 1, the probe is inserted into the minute hole of the object to be measured, the probe or the object to be measured is moved while the probe is inserted into the minute hole, and the probe comes into contact with the minute hole. The contact position at the time is stored. Then, the probe is brought into contact with the minute hole at a plurality of positions, a circle is identified from information on three or more contact points, and the hole diameter of the minute hole is calculated.

  In Patent Document 2, a chromatic point sensor (CPS) is used to measure a geometric characteristic such as a hole diameter without rotating the optical pen. Specifically, the CPS device having the optical pen provided with the beam splitting deflection element is provided, the optical pen is inserted into the hole, and the measurement light is simultaneously irradiated in three measurement directions orthogonal to the central axis of the optical pen. The reflected light is received through the confocal aperture of the optical pen. Then, the distance between the optical pen and the hole wall is obtained from the spectrum of the received reflected light, and the geometric characteristics such as the hole diameter are measured.

  Furthermore, although it is not a hole diameter, patent document 3 describes obtaining the outer diameter of a steel material using a laser. In this publication, the outer diameter of the steel material is measured over the entire length by using a laser scanning dimension measuring device composed of a projector and a light receiver. At that time, the optical axis of the dimension measuring device is arranged in two stages in the front and rear in the circumferential direction, and is installed in a direction perpendicular to the flow direction of the steel material conveying table, and the outer diameter position having different measurement timings in the two stages in the front and rear is the same cross section. Arithmetic processing is performed to obtain an outer diameter value on the circumference.

JP 2003-4433 A JP2015-114326A JP 2006-153545 A

  In the hole diameter measuring devices using the probes described in Patent Documents 1 and 2, the probe diameter is smaller than the hole diameter for convenience of inserting the probe into the hole. Therefore, in order to ensure the rigidity of the probe, whether it is a contact type or non-contact type, and in the case of an optical type, an outer diameter larger than a predetermined value is required for light irradiation and reflection detection, and the probe is small. There are restrictions on the conversion. For example, when the object to be measured is measuring a minute hole of 1 mm or less and further sub-mm or less, in the case of a contact type, the probe diameter becomes too small, and there is a risk that the rigidity is insufficient and it is difficult to ensure the function. Moreover, in the thing of patent document 3, since the objective is an outer diameter measurement, it is not considered about the measurement of a micropore diameter.

  On the other hand, when trying to measure the micropore diameter using an optical microscope, in order to clarify the edge of the hole, the contrast has to be increased, and inconvenience such as halation may occur. In addition, the influence of diffraction cannot be ignored. Furthermore, since it is calculated | required that a measurement target object is a magnitude | size mounted on a microscope etc., the measurement target object which can be used is limited. In the case of an electron microscope (SEM), it is necessary to put an object to be measured in a vacuum container, and pretreatment of the object to be measured may be required.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to accurately measure the diameter of a measurement object having a minute through hole having a hole diameter of 1 mm or less. Another object of the present invention is that, in addition to the above-described object, for a micro hole in which it is difficult to insert a probe, it is not necessary to insert the probe into the hole, and the micro hole diameter can be reduced without performing pretreatment for measurement. It is to measure.

  In order to achieve the above object, the present invention is characterized in that, in a hole diameter measuring apparatus for measuring the hole of a measurement object having a minute through hole, a white light source having a continuous spectrum and white light emitted from the light source A prism to be refracted, a placing means for placing the measurement object, a positioning means for positioning the light refracted by the prism in the vicinity of the hole of the measurement object, and a back side of the placement means. The light detection means for detecting the light that has passed through the hole, and the upper limit wavelength and the lower limit wavelength of the light that has passed through the hole are determined from the signal detected by the light detection means, And calculating means for calculating the hole diameter of the hole. The hole diameter measuring apparatus of the present invention can measure a minute through hole having an inner diameter of 1 mm or less, and is suitable for measuring such a minute through hole.

  In this feature, a mask having an opening having a larger diameter than the hole of the measurement object may be disposed on the lower surface side of the measurement object on the upper surface of the placing object, and holds the prism. Preferably, the holding means or the positioning means has a holding means, and a mechanism for holding the distance between the holding means and the measurement object constant is provided in the holding means or the positioning means.

  Further, a parallel light lens and a slit plate are arranged in this order from the prism side between the prism and the measurement object so that the slit plate can be moved in a direction perpendicular to the optical axis of the parallel light lens. The light detection means may be a CMOS, a CCD, a direct image sensor, or a color separation photodiode, and is arranged between the prism and the measurement object in order from the prism side and a parallel light lens. A slit plate is disposed, a condenser lens is disposed between the placing means and the light detection means, the slit plate is movable in a direction perpendicular to the optical axis of the parallel light lens, and the light detection means May be a photomultiplier tube.

Further, in the above feature, an upper limit wavelength used for measurement of light refracted by the prism is λa, a lower limit wavelength is λb, and a spread width of the light exiting the prism at a position corresponding to the upper surface of the measurement object is D. When the upper limit wavelength of the light detected by the light detection means is λa ′ and the lower limit wavelength is λb ′, the calculation means sets the diameter d of the hole as follows:
d = D × (λa′−λb ′) / (λa−λb) (Formula 1)
It is better to ask from.

Another feature of the present invention that achieves the above object is a method for measuring a hole diameter of a through hole having a hole diameter of 1.0 mm or less, in which white light emitted from a light source having a continuous spectrum is refracted by a prism. In what irradiates the measurement object, the spread range of light exiting the prism in a state where the reference height, which is the distance between the upper surface of the mounting means for placing the measurement object and the prism, is H D, a calibration step for obtaining the upper limit wavelength λa and the lower limit wavelength λb at that time, and placing the measurement object on the mounting means, and determining the distance between the upper surface of the measurement object and the prism as a reference height H A measurement step for obtaining an upper limit wavelength λa ′ and a lower limit wavelength λb ′ of light passing through the hole, and a calculation step for calculating the hole diameter d of the hole from the obtained values according to the following equation.
d = D × (λa′−λb ′) / (λa−λb) (Formula 1)

  In this feature, in the measurement step, a slit plate interposed between the prism and the measurement object may be moved in a direction substantially parallel to the upper surface of the measurement object.

  According to the present invention, the dispersed light is made to enter a minute hole having a diameter of 1 mm or less, which is an object to be measured, and the wavelength of the light passing through the hole is detected to measure the minute hole diameter. The microhole diameter can be measured. In addition, it is not necessary to insert the probe into the hole for the minute hole in which the probe is difficult to insert, and the diameter of the minute hole can be easily measured without performing pretreatment for measurement.

It is front sectional drawing of one Example of the hole diameter measuring apparatus which concerns on this invention, (a) shows the state at the time of calibration, (b) shows the state at the time of measurement. It is a figure explaining the measurement principle of a microhole diameter, (a) is an apparatus outline | summary, (b) is a spectrum range, (c) is a figure which shows the example of the gain of a detection means. It is a figure explaining Example 1 of this invention, (a) is a schematic front view, (b) is a figure which shows the detail of a mask part. It is front sectional drawing of the modification of the hole diameter measuring apparatus which concerns on this invention. It is front sectional drawing of the other modification of the hole diameter measuring apparatus which concerns on this invention.

  Hereinafter, several embodiments of a hole diameter measuring apparatus for micro holes according to the present invention will be described with reference to the drawings. In the following examples, the hole diameter of the target minute hole is 1 mm or less, and the hole is a through hole. In the present invention, the spectrum of light is used for measuring the hole diameter.

  FIG. 1 is a front sectional view of an embodiment of a hole diameter measuring apparatus 100 according to the present invention. FIG. 1 (a) shows a state during calibration of the hole diameter measuring apparatus 100, and FIG. The state at the time of measuring the hole diameter d of the hole 71 (it is also called a measurement hole or a measurement object hole) formed in the thing 70 is shown. First, the state at the time of calibration will be described with reference to FIG.

  The hole diameter measuring apparatus 100 includes a white light source 12 having a continuous spectrum, a prism 14 that refracts light emitted from the white light source 12 to generate a light spectrum, and a positional relationship between the white light source 12 and the prism 14. Prism holding means 10 having a casing 16 that holds the lamp while holding it. The white light source 12 includes a deuterium lamp having a continuous spectrum from a wavelength of 180 nm to 400 nm, a tungsten light having a continuous spectrum from a wavelength of 350 nm to 300 nm, or a xenon lamp having a continuous spectrum from a wavelength of 185 nm to 2000 nm. Etc. are used. As the prism 14, a prism made of normal dispersion glass having a refractive index of about 15 is used, but the prism is not limited to this, and various prisms can be used.

  In this embodiment, the white light source 12 is disposed on the upper left side of the casing 16 and radiates white light from the upper left side to the lower right side. The radiated light 81 radiated from the white light source 12 is incident on the prism 14 disposed below the white light source 12, and the refraction at the prism 14 changes according to the wavelength of the radiated light 81. And the upper wavelength side refracted light 83 on the long wavelength side, a light spectrum is formed.

  On the other hand, in order to place the measuring object 70, a table-like placing means 60 is disposed below the prism holding means 10. The placing means 60 is divided into a right part for measurement, which is covered with the prism holding means 10, and a left part where the positioning means 20 for moving the prism holding means 10 in the vertical direction is arranged. . An opening 61 having a sufficiently larger diameter than the measurement object hole 71 formed in the measurement object 70 is formed in the measurement portion of the mounting means 60.

  The opening 61 is an opening or a transparent plate is fitted therein, so that the spectrum of the light emitted from the prism 14, which will be described in detail later, can be detected. A mask 30 in which an opening 32 having a diameter approximately equal to or slightly smaller than the opening 61 formed in the measurement portion of the mounting means 60 is formed is disposed on the upper surface of the opening 61. The mask 30 is used to determine the spectrum of light that serves as a reference for the hole diameter measuring apparatus 100.

  The positioning means 20 includes a base 25 placed on the placing means 60, a rail 22 extending vertically upward from the base 25, and a slider 21 fitted to the rail 22. The rail 22 and the slider 21 may be linear motion means such as a ball spline or a linear motor, and may be configured to drive the slider 21 or the rail 22 with a stepping motor or the like, or may be manually moved up and down in the vertical direction. You may make it make it. When the slider 21 is moved manually, the rotary knob 23 attached to the slider 21 is rotated. The rotary knob 23 is also used to stop and hold the slider 21.

  The slider 21 is connected to the casing 16 of the prism holding means 10 by a support arm 24. When the slider 21 moves up and down, the prism 14 moves up and down together with the slider 21. A contact 18 is provided at a position on the lower surface of the prism holding means 10 that faces the upper surface of the mask 30, and the height from the upper surface of the mask 30 to the radiation position of the light exiting the prism 14 at the time of calibration. It is possible to keep H constant. In this embodiment, the contact 18 is used to make the height H from the upper surface of the mask 30 to the refractive light radiation position of the prism 14 constant at the time of calibration. It goes without saying that a distance device can be provided and the height H can be made constant by using it.

  On the lower surface side of the mounting means 60, a light detection means 40 that detects light that has passed through the opening 32 of the mask 30 at the time of calibration is provided at a portion of the opening 61 provided in the mounting means 60. As the light detection means 40, a photodiode 41 [described in FIG. 4A] such as a CCD, a CMOS, a direct image sensor, a color separation photodiode, or FOVEON manufactured by FOVEON, USA can be used. The detection signal of the light detection means 40 is sent to the calculation means 50.

  When calibrating the hole diameter measuring apparatus 100 configured as described above, first, the mask 30 is positioned so that the opening 32 thereof is positioned on the opening 61 of the mounting means 60. Next, the contact 18 provided on the lower surface of the prism holding means 10 is brought into contact with a portion other than the opening 32 of the mask 30, and the distance from the refracted light emitting surface of the prism 14 to the upper surface of the mask 30 is determined in advance. Set to the defined height H. Next, the light detection means 40 detects the spectrum of light originating from the white light source 12 that has passed through the opening 32 of the mask 30 and the opening 61 of the mounting means 60. At that time, the light detection means 40 limits the wavelength λb and the length of the lower limit side refracted light 82 on the short wavelength side of the spectrum passing through the opening 32 of the mask 30 having the inner diameter or the width D, which is blocked by the mask 30. The wavelength λa of the upper-side refracted light 83 on the wavelength side is detected. This completes the calibration.

  Next, the inner diameter of a hole (measuring hole) 71 actually formed in the measuring object 70 is measured. In the same state as at the time of calibration, the prism holding means 10 is moved upward, and the measuring object 70 is placed on the upper surface of the mask 30. At that time, the hole 71 of the measurement object 70 is positioned in the opening 32 of the mask 30. Next, the contact 18 attached to the lower surface of the prism holding unit 10 is brought into contact with the upper surface of the measuring object 70 using the positioning unit 20. Thereby, the height H from the refractive light radiation position of the prism 14 to the upper surface of the measuring object 70 can be matched with the height H at the time of calibration.

  When light having a continuous spectrum is emitted from the white light source 12 in this state, the radiated light 81 enters the prism 14 and is refracted to form a light spectrum. The radiated light 81 passes through the prism 14 and spreads in the same wavelength region between the lower limit side refracted light 82 and the upper limit side refracted light 83 as at the time of calibration, but the spectrum of light passing through the measurement hole 71 of the measurement object 70 is , The wavelength range between the hole entry lower limit light 85 and the hole entry upper limit light 86 is narrowed. The light detection means 40 disposed on the lower surface of the placing means 60 detects the wavelength λb ′ of the hole entry lower limit light 85 and the wavelength λa ′ of the hole entry upper limit light 86.

Since the data λa, λb, and D at the time of calibration are stored in the computing unit 50, the measurement hole of the measurement object 70 is obtained by using the data and the wavelengths λb ′ and λa ′ obtained by the current measurement. The inner diameter d of 71 is obtained by the following equation.
d = D × (λa′−λb ′) / (λa−λb) (Formula 1)

  The above measurement principle will be further described with reference to FIG. FIG. 2A is a diagram showing the main part of the hole diameter measuring device 100 extracted, and FIG. 2B is a diagram showing the spectrum of light generated by the prism 14 and the measurement object 70 on the spectrum. It is the figure which showed the position 110 of the hole 71 typically. FIG. 2C is a diagram schematically showing the magnitude Amp of the detection signal detected by the light detection means 40 as the vertical axis and the horizontal axis as the wavelength λ. In FIG. 2A, the mask 30 is omitted. In the case of calibration not using the mask 30, the reference position of the reference height H is the upper surface of the mounting means 60, and instead of the inner diameter of the opening 32 of the mask 30, the inner diameter of the opening 61 of the mounting means 60 is D. By using this, the above formula can be applied.

  When the light source 12 is a white light source having a continuous spectrum, the spectrum of the light that has been refracted by the prism 14 and passed through the opening 62 formed in the mounting means 60 is, for example, as shown in FIG. If a xenon lamp is used as the light source 12, it includes ultraviolet light λb to infrared light λa. That is, in addition to the visible light region, a region outside visible light is also included. In short, it is sufficient that a continuous spectrum from a short wavelength to a long wavelength can be used. This corresponds to the gain 112 detected by the light detection means 40 during calibration.

  On the other hand, since it can be visually confirmed at the time of measurement, the position 110 of the hole 71 of the measuring object 70 is set to be in the visible light range of the spectrum. In this embodiment, the short wavelength side is a purple range, and the long wavelength side is a yellow range. At this time, in the gain 111 of the light detection means 40, λb ′ is about 450 nm and λa ′ is about 550 nm.

  Next, a more specific example is shown in Example 1 with reference to FIG. FIG. 3A is a schematic front view of the measuring apparatus, and FIG. 3B is a view in which only the mask portion is taken out.

  A tungsten light source or a light source capable of emitting daylight light is used as the white light source 12. The light source 12 emits continuous light including a spectrum i line (365.01 nm) on the short wavelength side to a spectrum t line (1013.98 nm) on the long wavelength side. The prism 14 uses a HOYA-C7 (trade name) equivalent product that serves as a reference for normal dispersion glass. The apex angle μ formed by the incident side surface 1 and the output side surface 2 of the prism 14 is μ = 60 °.

First, a mask 30 having a known opening diameter or slit width is calibrated. The opening diameter or the aperture width of the mask 30 is _{D 1,} the three-dimensional measurement or the like using a _probe, which is D 1 = 2 mm. The radiated light 81 from the light source 12 incident on the prism 14 at the incident angle θ ₁ passes through the prism 14, due to the difference in the refractive index n of the spectrum of the light, the ultraviolet side (lower limit side) refracted light 5 and the infrared side ( The upper side is split between the refracted light 6. The spectrum of the split light is emitted from the prism 14 as a spectrum between the lower limit side refracted light 82 (λa = 365.01 nm) and the upper limit side refracted light 83 (λb = 1013.38 nm). The height H from the emission side surface 2 of the prism 14 to the upper surface of the mask 30 is H = 80 mm. Since the refractive index n for each spectrum of the prism 14 is known, the angle of deviation ε in each spectrum is obtained from (Expression 2) from Snell's law and the like.
Therefore, the difference [Delta] [epsilon] of the deflection angle epsilon ₁ of declination epsilon ₂ and lower side refracted light 82 of the upper side refracted light 83 is obtained in Δε = ε ₁ -ε _2. Since the reference width D is a function D = f (Δε, H) of the deviation difference Δε and the height H, the calibration is completed by comparing it with the reference width D obtained by (Equation 3). The reference width D was D = 2.76854 mm.

D ₁ = D × (λa ₁ −λb ₁ ) / (λa−λb) (Formula 3)
Since the light detection means 40 has detected that the spectrum of the light that has passed through the opening 32 of the mask 30 is 455.086 nm to 923.903 nm, D ₁ = 2.00 mm is obtained.

  Next, the measuring object 70 in which the hole 71 is formed is placed on the mask 30 with the height H from the prism 14 to the upper surface set to 80 mm. Similarly to the measurement of the mask 30, the light detection means 40 that radiates the emitted light 81 from the light source 12 to the prism 14 and is disposed on the back side of the mask 30 causes the light that has passed through the hole 71 and the opening 32 of the mask 30. Detect the spectrum. At this time, the wavelength λa ′ of the hole entry lower limit light 85 was λa ′ = 500 nm, and the wavelength λb ′ of the hole entry upper limit light 86 was λb ′ = 680 nm. Using (Expression 1), the diameter d of the hole 71 is obtained as d = 0.769 mm.

When the above calculation is performed assuming that there is an error of ± 0.05 mm as the measurement error in the width D ₁ of the opening 32 of the mask 30, the error Δd of the hole diameter d is about Δd = ± 0.0187 mm. It was. Therefore, it was confirmed that the micropore diameter can be measured with high accuracy by the method of this example.

  Next, a modification of the above embodiment of the present invention will be described with reference to FIGS. The modification shown in FIG. 4 is significantly different from the above-described embodiment in that a parallel light lens 15 and a slit plate 90 that can move in the horizontal direction are provided between the prism 14 and the measurement object 70. In FIG. 4A, the other components are the same as those of the embodiment shown in FIG. 1, but in FIG. 4B, a condensing lens 42 is further provided on the light detection means 40 side.

  These are intended to more accurately measure the spectrum by guiding the light split by the prism 14 to the measurement object 70 as parallel light and allowing only a predetermined spectrum of light to pass vertically through the hole 71. It is. Therefore, the slit plate 90 is formed with a slit 95 having a spectral width only. The width of the slit 95 is preferably as narrow as possible, but is about 50 μm in consideration of workability.

  In order to make the slit plate 90 movable in the horizontal direction, the casing 16 is provided with a hole for moving the slit plate 90 and a slide bearing 17 that supports the slit plate 90 so as to be able to move linearly. A rack 91 is attached to the outside of the casing 16 of the slit plate 90 and meshes with a pinion 92 connected to a servo motor 93 (a stepping motor may be used instead of the servo motor). The movement of the slit plate 90 is controlled by controlling the servo motor 93. In this embodiment, the slit plate is moved by the servo motor. However, for example, a variable slit made by Sigma Kogyo may be provided below the condenser lens.

  In the light detection means 40 of FIG. 4B, a casing 43 is provided below the placement means 60 in order to hold the condenser lens 42 and the photomultiplier tube 44 that detects the light that has passed through the condenser lens 42. ing. The spectrum of the light that has passed through the minute hole 71 is collected by the condenser lens 42 and amplified by the photomultiplier tube 44 to improve the detection accuracy. 4A and 4B, the spectrum passing through the minute hole 71 is measured in synchronization with the movement of the slit plate 90.

  In FIG. 5, a grating 47 and a line sensor 48 are provided in the light detection means 40 in the embodiment shown in FIG. 1. The spectrum that has passed through the minute holes 71 is detected by a line sensor (photodiode or the like) 48 that is arranged in large numbers up and down, changing its traveling direction with a grating 47. The hole entry lower limit light (short wavelength side) 45 is detected by the sensor above the line sensor 48, and the hole entry upper limit light (long wavelength side) 46 is detected by the sensor below the line sensor 48, so that each wavelength (spectrum) ) The strength of each can be understood and the hole diameter can be measured. Instead of the light detection means 40 shown in this modification, for example, a spectroscope BW-T6 manufactured by Konica Minolta Co., Ltd. having the same function is connected to the back side of the mounting means 60 for detection. You may do it.

  In short, in the present invention, the diameter of a minute hole is accurately measured only by detecting the wavelength of the light that has passed through the hole by allowing the dispersed light to enter a minute hole having a diameter of 1 mm or less, which is an object to be measured. All embodiments within the spirit of the invention are within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Incident side surface 2 ... Outgoing side surface 5 ... Ultraviolet side (lower limit side) refracted light, 6 ... Infrared side (upper limit side) refracted light, 10 ... Prism holding means, 12 ... White light source, 14 ... Prism (refractive means) 15 ... Parallel light lens, 16 ... Casing, 17 ... Slide bearing, 18 ... Contact, 20 ... Positioning means, 21 ... Slider, 22 ... Rail, 23 ... Rotating knob, 24 ... Support arm, 25 ... Base, 30 ... Mask: 32 ... Aperture, 40 ... Photodetection means, 41 ... CCD or CMOS, 42 ... Condenser lens, 43 ... Case, 44 ... Photomultiplier tube, 45 ... Hole entry lower limit light, 46 ... Hole entry upper limit light, 47 ... Grating, 48 ... Line sensor (photodiode), 50 ... Calculation means, 60 ... Placing means, 61 ... Opening or transparent part, 70 ... Measurement object, 71 ... Measurement hole (microhole), 81 ... Radiation light , 82 ... Limit side refracted light, 83 ... Upper limit side refracted light, 85 ... Hole entry lower limit light, 86 ... Hole entry upper limit light, 90 ... Slit plate, 91 ... Rack, 92 ... Pinion, 93 ... Servo motor, 95 ... Slit, 100 ... Hole diameter measuring device 110: Measurement hole position, 111: Refraction light gain, 112: Hole entry light gain, d: Hole diameter, D: Reference width (expansion width), D ₁ : Mask opening diameter or opening width, H: Reference height, θ ₁ ... Incident angle, ε ... Declination, λ ... Wavelength, λa ... Refraction light upper limit wavelength, λa '... Hole entry light upper limit wavelength, λb ... Refraction light lower limit wavelength, λb' ... Hole entry light Lower limit wavelength, μ ... Vertical angle

Claims (8)

In the hole diameter measuring device for measuring the diameter of the hole of the measurement object having a through hole,
A white light source having a continuous spectrum;
A prism that refracts white light emitted from the light source;
Mounting means for mounting the measurement object;
Positioning means for positioning the light refracted by the prism in the vicinity of the hole of the measurement object;
A light detecting means arranged on the back side of the placing means for detecting light passing through the hole;
An arithmetic means for obtaining an upper limit wavelength and a lower limit wavelength of light that has passed through the hole from a signal detected by the light detection means, and calculating a hole diameter of the hole using the obtained upper limit wavelength and lower limit wavelength;
A hole diameter measuring device comprising:   2. The hole diameter measurement according to claim 1, wherein a mask having an opening larger in diameter than the hole of the measurement object is disposed on the lower surface side of the measurement object on the lower surface side of the measurement object. apparatus.   The holding means or the positioning means has a holding means for holding the prism, and a mechanism for holding a distance between the holding means and the measurement object constant is provided in the holding means or the positioning means. The hole diameter measuring device described.   A parallel light lens and a slit plate are arranged in order from the prism side between the prism and the measurement object, and the slit plate is movable in a direction perpendicular to the optical axis of the parallel light lens, 4. The hole diameter measuring apparatus according to claim 1, wherein the light detection means is any one of a CMOS, a CCD, a direct image sensor, and a color separation photodiode.   A parallel light lens and a slit plate are arranged in this order from the prism side between the prism and the measurement object, and a condenser lens is arranged between the placing means and the light detecting means, and the slit The hole diameter measurement according to any one of claims 1 to 3, wherein a plate is movable in a direction perpendicular to the optical axis of the parallel light lens, and the light detection means is a photomultiplier tube. apparatus. The upper limit wavelength used for measurement of the light refracted by the prism is λa, the lower limit wavelength is λb, the spread width of the refracted light at the position corresponding to the upper surface of the measurement object is D, and the light detecting means When the upper limit wavelength of the detected light is λa ′ and the lower limit wavelength is λb ′, the calculation means sets the hole diameter d of the hole,
d = D × (λa′−λb ′) / (λa−λb)
The hole diameter measuring device according to any one of claims 1 to 5, wherein the hole diameter measuring device is obtained from: A method for measuring the diameter of a through hole,
In what irradiates a measurement object by refracting white light emitted from a light source having a continuous spectrum with a prism,
The spread range D of the refracted light from the prism and the upper limit wavelength λa and the lower limit wavelength λb at that time, with the distance between the upper surface of the mounting means for mounting the measurement object and the prism being H, The desired calibration step,
A measurement step of placing the measurement object on the placing means, and determining an upper limit wavelength λa ′ and a lower limit wavelength λb ′ of light passing through the hole, where H is a distance between the upper surface of the measurement object and the prism; ,
And a calculation step of calculating the hole diameter of the hole from the obtained values according to the following equation.
d = D × (λa′−λb ′) / (λa−λb)   The hole diameter according to claim 7, wherein in the measurement step, a slit plate interposed between the prism and the measurement object is moved in a direction substantially parallel to the upper surface of the measurement object. Measurement method.