WO1997048968A1 - Appareil optique confocal - Google Patents

Appareil optique confocal Download PDF

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Publication number
WO1997048968A1
WO1997048968A1 PCT/JP1997/001944 JP9701944W WO9748968A1 WO 1997048968 A1 WO1997048968 A1 WO 1997048968A1 JP 9701944 W JP9701944 W JP 9701944W WO 9748968 A1 WO9748968 A1 WO 9748968A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
amount
confocal optical
photodetector array
measured
Prior art date
Application number
PCT/JP1997/001944
Other languages
English (en)
Japanese (ja)
Inventor
Shigeyuki Tada
Hiroshi Tanaka
Takayoshi Endoh
Masato Moriya
Original Assignee
Komatsu Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Komatsu Ltd. filed Critical Komatsu Ltd.
Publication of WO1997048968A1 publication Critical patent/WO1997048968A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/0004—Microscopes specially adapted for specific applications
    • G02B21/002—Scanning microscopes
    • G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
    • G02B21/0036—Scanning details, e.g. scanning stages
    • G02B21/004—Scanning details, e.g. scanning stages fixed arrays, e.g. switchable aperture arrays

Definitions

  • the present invention relates to a confocal optic used in a three-dimensional shape inspection apparatus for quickly inspecting a three-dimensional shape, for example, a shape of an object to be measured, such as a solder bump for IC mounting, whose approximate surface shape is known. It concerns equipment. Background art
  • This type of confocal optical device is configured as shown in FIG.
  • the light from the light source 1 is reflected by the mirror 40, becomes parallel light via the magnifying lenses 2a and 2b, and enters the hologram 3 as reference light.
  • the hologram 3 reproduces light equivalent to a point light source emitted from each pinhole position of the pinhole array 4 in which pinholes are two-dimensionally arranged by diffracting the reference light.
  • Fig. 1 represents the light at one pinhole position.
  • ⁇ Reflected light with pinhole array 4 It shows how to form an image nearby. According to this, as shown in FIG. 3, the reflected light passes through the pinhole 4a of the pinhole array 4 only when the focal point and the surface of the object 6 are coincident (focused). That is, as shown in FIG. 2, the light spot is located after the reflecting surface (front surface) of the object 6 (rear pin), or as shown in FIG. In the case of), the reflected light is blocked by the pinhole array 4 and can hardly pass therethrough, so that a so-called light receiving aperture function is performed.
  • FIG. 1 has the confocal optical system described with reference to FIGS.
  • the first and second objective lenses 5a and 5b are both composed of a telecentric system (also referred to as an afocal system or a tandem arrangement optical system). Instead of moving the object 6 in the Z direction, move the first objective lens 5a in the Z direction and measure.
  • the light passing through the pinhole 4a is coupled to a photodetector array 8 for detecting two-dimensional light via first and second relay lenses 7a and 7b.
  • the light that is imaged and passes through each pinhole 4a is imaged and measured on an independent photodetector.
  • the control device 9 controls the XY position of the stage 10 on which the object 6 is placed (if necessary, the offset position in the Z direction), determines the measurement field of view, and determines the first objective lens. 5 Moves a in the Z direction and reads the measured value of the photodetector array 8 while detecting the position in the Z direction, performs peak processing, and displays, outputs, or records the result.
  • FIG. 5 shows a conventional peak processing device in a confocal optical device.
  • the amount of movement of the stage 10 (or the first objective lens 5 a) in the Z-axis (optical axis direction) is detected by the Z-axis encoder 13, and each movement from the photodetector array 8 is detected.
  • the detected values D11, D12, ... corresponding to the pixels are compared by the comparator 14 with the memory values Pll, P12, ... stored in the peak value memory 15. If the detected values Dll, D12, ... are higher than the memory values Pll, P12, ..., the value of the Z-axis encoder 13 is changed to Z by the data selector 16.
  • Reference numeral 18 denotes a data bus, which is used to transfer the values of the memories 15 and 17.
  • FIG. 6 shows a flowchart when one sampling is performed by the peak processing apparatus.
  • the memories of the Z value memory 17 and the peak value memory 15 are cleared, and the indices i, j, and x in the X, ⁇ , and Z directions are cleared. Clear k and initialize (Step 1).
  • the slice number k in the Z direction and one of the detected values D ll, D 12,... corresponding to each pixel of the photodetector array 8 The i and j are incremented in the pixels of step (steps 2 and 3), and the detection value D of one pixel in the photodetector array 8 is calculated.
  • Step 4 is read out (step 4), and is compared with the corresponding memory value P ij of the peak value memory 15 by the comparator 14 (step 5).
  • step 5 is input from the comparator 14 to the data selector 16, and the Z-axis encoder 13 at this time detects the signal.
  • the value is written into the Z value memory 17 and the value of the memory value P ij is updated to the value of the detected value D ij.
  • the writing and updating of the Z-value memory 17 are skipped.
  • L x M measurement field of view
  • N in step (8) indicates the number of slices in the Z-axis direction.
  • solder bump for mounting an IC as described above. It measures the height from the ground.
  • the object to be measured is a solder bump, as shown in FIG. 7, the solder bump 11 is higher than the surface of the IC substrate 12 and is opposed to the surface of the IC substrate 12. Then, the height of the solder bump 11 from the surface of the IC substrate 12 is measured by performing a peak treatment on the top surface of the solder bump 11.
  • the solder bumps 11 and the IC substrate 12 are different in material and manufacturing method, the light reflectance of the two differs. For example, the reflectivity of the surface of the solder bump 11 is low, and the reflectivity of the surface of the IC substrate 12 is higher than that of the solder bump 11.
  • the dynamic range for the amount of light received by the photodetector array 8 is finite.
  • An object of the present invention is to provide a confocal optical device that solves the above problems. Disclosure of the invention
  • the confocal optical system is arranged in one-dimensional or two-dimensional direction, and the reflected light from the object to be measured passes through the light-receiving pinhole array and is received by the photodetector array, and is received by the photodetector array Confocal optics that measures the height of the object to be measured by performing peak processing on the amount of light In the device,
  • the intensity of the reflected light in the portion where the amount of reflected light is larger than that of the solder bump portion of the IC substrate or the like exceeds the dynamic range of the photodetector array Peak processing of the reflected light is disabled, and then continues in the same field of view. Therefore, the height measurement by peak processing of the part that reflects the amount of light exceeding the dynamic range of the photodetector array becomes invalid, and the height is measured by the difference from the height of the surface of the IC substrate. In such a determination of the height of the solder bump, the amount of reflected light is not affected by a portion larger than a predetermined amount, and the determination of the height of the solder bump can be reliably performed.
  • the confocal optical system is arranged in one-dimensional or two-dimensional direction, and the reflected light from the object to be measured passes through the light-receiving pinhole array and is received by the photodetector array.
  • a confocal optical device that measures the height of an object to be measured by performing peak processing on the amount of received light
  • a shutter is provided between the photodetector array and the light source, and a shutter that changes the amount of transmitted and integrated light in accordance with the intensity of the reflected light from the object to be measured.
  • the integrated light amount of the reflected light incident on the photodetector array from the detected object is not changed by opening and closing the shutter.
  • the integrated transmitted light amount due to the opening and closing of the shutter can be changed during the peak processing, whereby the amount of light received by the photodetector array when the amount of reflected light from the measured object is large is a predetermined amount. Since the amount of light can be reduced, the peak processing by the reflected light of the portion having high light reflectance such as the IC substrate can be performed similarly to the portion having low reflectance of other light.
  • the confocal optical system is arranged in one-dimensional or two-dimensional direction, and the reflected light from the object to be measured passes through the light-receiving pinhole array, is received by the photodetector array, and is received by the photodetector array.
  • a confocal optical device that measures the height of an object to be measured by performing peak processing on the amount of light
  • light intensity modulation means for modulating the intensity of light from the light source.
  • the reflected light from the object to be measured can be changed by operating the light intensity modulating means to modulate the intensity of the light from the light source.
  • the amount of reflected light incident on the photodetector array from the object to be measured can be changed during peak processing, whereby the amount of reflected light from the object to be measured is increased when the amount of reflected light from the object to be measured is large.
  • the light intensity modulating means may be blinking means of the light source. No.
  • the light amount of the light source can be changed according to the ratio of turning on and off the light source, the light amount incident on the object to be measured can be easily changed by the blinking operation of the light source.
  • the light intensity modulating means may be a variable light amount adjusting means.
  • the light amount from the light source can be changed by changing the light transmittance of the variable light amount adjusting means.
  • variable light quantity adjusting means is made of a material that partially absorbs light
  • variable light quantity adjusting means can be composed of an optical element, and the configuration can be simplified.
  • FIG. 1 is an explanatory diagram showing a configuration of a conventional confocal optical device.
  • FIG. 2 is an explanatory diagram showing an image forming state of the reflected light in the vicinity of the pinhole in the conventional device E.
  • FIG. 3 is an explanatory view showing an image forming state of a reflected light near a pinhole in the conventional device.
  • FIG. 4 is an explanatory diagram showing an image forming state of a reflected light near a pinhole in the conventional device.
  • FIG. 5 is a configuration diagram showing a conventional peak processing device in a confocal optical device.
  • FIG. 6 is a flowchart showing conventional peak processing.
  • FIG. 7 is an explanatory diagram showing the difference in the amount of reflected light between the IC substrate and the solder bump.
  • FIG. 8 is an explanatory diagram showing a conventional peak process when the reflected light amount is higher than the effective received light amount.
  • FIG. 9 is an explanatory diagram showing the peak processing when the amount of reflected light is higher than the effective amount of received light in the present invention.
  • FIG. 10 is an explanatory diagram showing a peak processing device in the first embodiment of the confocal optical device of the present invention.
  • FIG. 11 is a flowchart showing the peak processing in the present invention.
  • FIG. 12 is a structural explanatory view showing a second embodiment of the confocal optical device of the present invention.
  • FIG. 13 is an operation explanatory view of the second embodiment.
  • FIG. 14 is a configuration explanatory view showing a third embodiment of the confocal optical device according to the present invention.
  • FIG. 15A, FIG. 15B, FIG. 15C, and FIG. 15D are explanatory diagrams each showing a different configuration of the transmittance variable filter.
  • the first embodiment of the present invention has the same configuration as the confocal optical device shown in FIG. have.
  • the set amount of received light Vc by the photodetector array 8 is equal to or smaller than the dynamic range Vs of the photodetector array 8. (VcVs).
  • VcVs the dynamic range of the photodetector array 8.
  • FIG. 10 shows an apparatus for performing the above processing according to the processing algorithm shown in FIG. 11 during the peak processing.
  • the peak processing will be described below with reference to both figures.
  • the memories of the Z value memory 17 and the peak value memory 15 are cleared, and the X, ⁇ , and Z directions are stored. Clear and initialize indexes i, j, and k (Step 1). Then, the slice number k in the Z-axis direction and the detection value (detected light amount) D i; j corresponding to each pixel of the photodetector array 8 are the inks of i and j in one pixel of j.
  • the detected light amount D ij at one pixel in the photodetector array 8 and the set received light amount Vc in the photodetector array 8 are compared with the first comparator 1 Compare at 4a (Step 4).
  • D ij> V c ⁇ and ⁇ 0 are selected in both the Z value memory 17 and the peak value memory 15 data selectors 16 and 16a, and these are selected as the respective memories.
  • Input to 17 and 15 Step 5).
  • ⁇ 0 is a special value, for example, peak value memory 15
  • the data is 8-bit data, select the maximum value of the data, such as 255, and once P0 is input to the peak value memory 15 and set Then, in the comparison between the detected light amount D ij in the second comparator 14 b described later and the memory value P ij of the peak value memory 15, P ij ⁇ D ij is always obtained. Writing to the value memory 17 and updating of the peak value memory 15 will never occur again. That is, the memory values of the Z value memory 17 and the peak value memory 15 are not updated. If the value of Z 0 is set to a special value such as 0, for example, whether the peak processing is enabled or disabled can be determined from the Z value memory 17 itself. That is, if the value of the Z value memory 17 is Z0, it can be determined that the peak processing of this pixel is invalid.
  • Peak processing in (7) becomes invalid.
  • step (4) if D ij ⁇ Vc, the detected light amount D ij and the memory from the peak value memory 15 in the second comparator 14 b are used.
  • the value P ij is compared with the value P ij (Step 8).
  • D ij> P ij the value Z ij of the Z-axis encoder 13 is written to the Z value memory 17 and the peak value memory 17 is written.
  • the memory value P ij of 15 is updated to the value of the detected light amount D ij (step 9). Thereafter, the process proceeds to steps (6) and (7) to perform peak processing.
  • a memory for recording data invalidity judgment is prepared, and data corresponding to each measurement point is prepared. You may try to set this The invalidation of the peak processing is continued for one field of view measurement, and the indexes i, j, k and the memories 15 and 17 are cleared (initialization of the peak value of another field of view (step 1)). ).
  • FIG. 12 shows a second embodiment of the confocal optical device according to the present invention.
  • a shutter 19 is interposed on the light receiving side of the photodetector array 8. Then, as shown in Fig. 13, when measuring the surface height of the IC substrate 12 and the surface height of the solder bump 11 by peak processing, the vicinity of the surface of the IC substrate 12 (Z 1 to Z 2), the opening time of the shutter 19 during the peak processing is shortened, and the integrated light amount of the reflected light R l incident on the photodetector array 8 is detected by light detection. Limit the amount of light that does not cause the detector array 8 to saturate.
  • the opening time of the shutter 19 at the time of peak processing near the top (Z 2 to Z 3) of the solder bump 11 having a lower light reflectance than the surface of the IC substrate 12 is set as described above. Only near the surface of IC substrate 1 and 2 By increasing the length, the integration time of the reflected light R2 incident on the photodetector array 8 is increased so that a sufficient amount of detected light can be obtained within a range where the photodetector array 8 is not saturated. I do.
  • the area of the measurement range Z is set more than the above-mentioned two divisions in accordance with the characteristics of the measurement object, and the reflected light of the object in each area is adjusted to the dynamic range V of the photodetector array. It may be possible to effectively observe within the range of s.
  • the configuration of the shutter 19 uses a conventionally known means, and the opening / closing operation thereof is controlled by the control device 9.
  • the shutter 19 may be placed anywhere between the photodetector array 8 and the object 6 and between the light source 1 and the hologram 3 in addition to the position shown in FIG. In particular, when the photodetector array 8 is a commercially available CCD camera, it is effective to use an electronic shutter.
  • the same effect can be obtained by blinking the light source 11 itself instead of the shutter. That is, by shortening the lighting time, the photodetector array 8 is prevented from being saturated in the portion where the amount of reflected light is large, and the lighting time is lengthened in the portion where the amount of reflected light is small, and this portion is used. A sufficient amount of light may be obtained in the photodetector array 8.
  • the timing of the shutter and the lighting of the light are performed so as to be synchronized with the movement of the photodetector array 8 or the stage 10 in the Z direction.
  • the light amount of the light source 1 may be changed.
  • an optical element capable of changing the amount of transmitted light in the light projection path from the light source 1 for example, a variable transmittance filter 20 is used as the light source 1.
  • hologram 3 It may be arranged between them, and the intensity of light to be projected on the object 6 may be adjusted according to Z 1 to Z 2 and ⁇ 2 to ⁇ 3 shown in FIG.
  • the transmittance variable filter 20 As an example of the transmittance variable filter 20, as shown in FIG. 15 ⁇ , the light from the light source 1 is converted into a linearly polarized light, and a polarizing plate 21 is used. In some cases, the amount of transmitted light is changed by rotating the polarizing plate 21.
  • a polarizing element 22 and a polarizing plate 21 are used for linearly polarized light, and the polarization direction is changed by the polarizing element 22 for the linearly polarized light.
  • the amount of light transmitted through 21 may be changed.
  • a 1/2 wavelength plate or the like may be used for the polarizing element 22 and this may be rotated by a motor, or a change in voltage or magnetic field, such as a liquid crystal or Faraday element.
  • the polarization plane may be rotated by the rotation.
  • the polarizing element 22 and the polarizing mirror 23 are used for the linearly polarized light, and the polarization direction is changed by the polarizing element 22 for the linearly polarized light.
  • the amount of light that reflects or transmits 3 may be changed.
  • filters 24 a, 24 b, 24 c, etc. having variously changed light transmittance are arranged on the disk 24, and the disk is rotated.
  • the amount of transmitted light may be changed by changing the value.
  • a filter whose transmittance continuously changes in the circumferential direction on the disk may be used.
  • the transmittance of these filters is determined by the absorption of light, and any of these filters may be used.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Microscoopes, Condenser (AREA)

Abstract

La présente invention concerne un système optique confocal se présentant selon une ou deux dimensions. En l'occurrence, une matrice photodétectrice (4) détecte au travers d'une matrice de trous d'épingle la lumière réfléchie par un objet (11, 12). Un traitement des pointes d'intensité de la lumière reçue par la matrice photodétectrice permet de mesurer la hauteur de l'objet. Si l'intensité lumineuse reçue par la matrice photodétectrice dépasse une énergie lumineuse fixée dans les limites d'une plage dynamique (Vs) de la matrice photodétectrice, le traitement des pointes d'intensité lumineuse n'est plus pris en considération.
PCT/JP1997/001944 1996-06-21 1997-06-06 Appareil optique confocal WO1997048968A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP16169396A JPH109825A (ja) 1996-06-21 1996-06-21 共焦点光学装置
JP8/161693 1996-06-21

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Publication Number Publication Date
WO1997048968A1 true WO1997048968A1 (fr) 1997-12-24

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WO (1) WO1997048968A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000033025A1 (fr) * 1998-11-30 2000-06-08 Olympus Optical Co., Ltd. Instrument de mesure

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004059526B4 (de) * 2004-12-09 2012-03-08 Sirona Dental Systems Gmbh Vermessungseinrichtung und Verfahren nach dem Grundprinzip der konfokalen Mikroskopie
KR100939537B1 (ko) * 2007-12-14 2010-02-03 (주) 인텍플러스 표면 형상 측정 시스템 및 그를 이용한 측정 방법
JP5412959B2 (ja) * 2009-02-02 2014-02-12 株式会社高岳製作所 光応用計測装置
JP6508992B2 (ja) * 2015-03-16 2019-05-08 株式会社ミツトヨ 光電式エンコーダ

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Publication number Priority date Publication date Assignee Title
JPS4838758A (fr) * 1971-09-14 1973-06-07
JPH02145904A (ja) * 1988-11-28 1990-06-05 Hitachi Ltd パターン検査方法およびそれに用いるパターン検査装置
JPH0413908A (ja) * 1990-05-08 1992-01-17 Fujitsu Ltd 高さ測定装置
JPH08152308A (ja) * 1994-09-30 1996-06-11 Komatsu Ltd 共焦点光学装置
JPH0961720A (ja) * 1995-08-29 1997-03-07 Olympus Optical Co Ltd 共焦点走査型光学顕微鏡及びこの顕微鏡を使用した測定方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4838758A (fr) * 1971-09-14 1973-06-07
JPH02145904A (ja) * 1988-11-28 1990-06-05 Hitachi Ltd パターン検査方法およびそれに用いるパターン検査装置
JPH0413908A (ja) * 1990-05-08 1992-01-17 Fujitsu Ltd 高さ測定装置
JPH08152308A (ja) * 1994-09-30 1996-06-11 Komatsu Ltd 共焦点光学装置
JPH0961720A (ja) * 1995-08-29 1997-03-07 Olympus Optical Co Ltd 共焦点走査型光学顕微鏡及びこの顕微鏡を使用した測定方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000033025A1 (fr) * 1998-11-30 2000-06-08 Olympus Optical Co., Ltd. Instrument de mesure
US6486964B2 (en) 1998-11-30 2002-11-26 Olympus Optical Co., Ltd. Measuring apparatus

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