TW201445109A - Three-dimensional profile acquisition device, pattern inspection apparatus, and three-dimensional profile acquisition method - Google Patents

Abstract

A three-dimensional profile acquisition device includes: a light source (43) emitting light with broader spectrum width, an interferometer (42) having a scanning part (55) and an imaging part (41), the scanning part (55) being configured to scan at a crisscross direction along the inspected plane (12a), wherein the scanning part (55) divides the light emitted from the light source (43) into a measuring light beam and a reference light beam, the inspected plane (12a) reflecting the measuring light beam, a reference mirror (49) reflecting the reference light beam, such that the first reflected light from the inspected plane (12a) and the second reflected light from the reference mirror (49) are converged to generate an interference fringe, the imaging part (41) using the exposure time above the cycle of the interference fringe to image the first reflected light and the second reflected light as a plurality of images; a control part (60) for controlling the scanning part (55) to perform scanning at a crisscross direction along the inspected plane (12a), and controlling the light source (43) to blink as the same cycle as the interference fringe; and an image resolving part (32) for inspecting the peak position of the interference fringe at the scanning direction of the scanning part (55) according to the plurality of images imaged by the imaging part (41) for each pixel of the images, and generating three-dimensional profile according to the peak position of each pixel inspected.

Description

Three-dimensional contour acquisition device, pattern detection device and three-dimensional contour acquisition method

The present invention relates to a three-dimensional contour acquiring device that optically measures a height distribution of a surface to be measured, obtains a three-dimensional contour, a pattern detecting device including a three-dimensional contour acquiring device, and a three-dimensional contour acquiring method.

As such a three-dimensional contour acquisition device, a foreign matter detecting device using an interferometer (for example, Patent Document 1), a depth measuring device using an interferometer (for example, Patent Document 2), and a surface shape measuring device using an interferometer are known. (for example, Patent Document 3).

For example, the foreign matter detecting device described in Patent Document 1 includes an interferometer including a laser light source, and the foreign matter is inspected by a laser interference method. Therefore, when there are two laser beams with different optical paths converging, the optical path difference between the two laser beams is not changed, but the interference grating is often generated, which makes it difficult to carry out the height distribution of the inspection object surface. Measurement.

In contrast, the measurement device described in Patent Document 2 and Patent Document 3 includes an interferometer that emits a white light source, and measures the depth or the surface shape by a white light interference method. That is, in the depth measuring device described in Patent Document 2, the spectroscope divides the white light beam into a measuring beam for projecting to the sample through the object lens, and a reference beam for reflecting to the reference mirror. The raster scanning means changes the relative optical path length difference between the measuring beam and the reference beam. An interference beam is generated by converging the reflected light from the sample with the reflected light from the reference mirror. Light detection means (for example, line sensor) for receiving an interference beam and generating a raster scan signal number. The signal processing circuit generates depth information of the concave portion based on the displacement information of the raster scanning signal from the light detecting means (for example, the line sensor) and the relative position information between the receiving lens and the sample.

Further, in the surface shape measuring apparatus described in Patent Document 3, the white light from the white light source is limited to a specific frequency spectrum by a band pass filter, and the white light is irradiated to a relative distance by the driving portion. The changed reference surface and the measurement target surface. The reflected light from the reference surface and the reflected light from the surface of the measurement target are combined, and an interference grating is generated in response to the optical path difference of the two reflected light beams. The CCD camera performs imaging of the measurement target surface together with the interference grating. The CPU samples the intensity value of the interference light that changes at a specific portion of the measurement target surface at a predetermined sampling interval. Furthermore, the CPU estimates a specific function having a peak position that coincides with the peak position of the interference light based on the spectral width of the specific frequency spectrum. By determining the height of the peak position of the characteristic function, the CPU can measure the uneven shape of the object surface.

[First technical literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei 10-293100.

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2009-36563.

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2001-66122.

However, when the measuring device of the white light interferometry described in Patent Document 2 is used, the short sampling frequency (the scanning distance is 100 nm or less) of 1/3 or less of the interference grating wavelength (5 nm in the example of Patent Document 2) And caused by the use of light detection means, Multiple (more than three) imaging processes are performed between single cycles of the interference grating. In this case, when the scanning distance to be scanned in the direction perpendicular to the surface to be measured is set to, for example, 50 μm, the scanning operation of one time must image an image of several hundred to 1000 degrees, and have The problem that the measurement time becomes quite lengthy exists.

Further, in the surface shape measuring apparatus using the white light interferometry described in Patent Document 3, since the sampling can be performed at a time interval longer than the period of the interference grating, the image imaged by the camera is performed in one scanning operation. The number of sheets can be reduced. However, since it takes time to estimate the calculation of the specific function, even if the number of samplings can be reduced, the surface shape measurement processing cannot be speeded up.

It is an object of the present invention to provide a three-dimensional contour acquisition device, a pattern detection device, and a three-dimensional contour acquisition method that can obtain a three-dimensional contour indicating a height distribution of a surface to be measured by a relatively simple process.

An aspect of the present invention provides a three-dimensional contour acquisition device including: a light source having a wide spectral width; and an interferometer including a scanning portion and an imaging portion, the scanning portion being configured to be along the pair Scanning in a direction in which the measurement surface intersects, wherein the scanning unit separates the light from the light source into a measurement beam and a reference beam, and the measurement surface reflects the measurement beam, and the reference beam is reflected by the reference mirror. The first reflected light from the surface to be measured is merged with the second reflected light from the reference mirror to generate an interference grating, and the imaging portion is formed by imaging the first reflection at an exposure time of a period equal to or longer than the period of the interference grating The light and the image of the second reflected light are a plurality of images; and the control unit controls the scanning unit to scan in a direction intersecting the measurement surface, and to cause the light to be The source is controlled to perform dot-off flicker in a state in which the period of the interference grating is the same period; and an image analyzing unit that is respectively formed in the image according to the plurality of images imaged by the image forming unit The pixel detects the peak position of the interference grating in the scanning direction of the scanning unit, and generates a three-dimensional contour in accordance with the detected peak position of each pixel.

In the above configuration, the control unit is configured to reciprocate the scanning unit in a direction intersecting the measurement surface, and to shift the light source between the scanning unit and the returning time. The phase is preferred.

In the above configuration, the three-dimensional contour acquiring device further includes a photo sensor that receives the first reflected light and the second reflected light that partially face the imaging portion, and generates the first reflected light and the second reflected light. Preferably, the control unit is configured to cause the light source to blink in the same phase as the interference grating according to the received light signal of the photo sensor.

In the above configuration, the exposure time of the image forming portion is preferably set to a value within a range of 1/4 to 1/3 of the period during which the interference grating is generated.

An aspect of the present invention provides a pattern detecting device including a pattern inspection unit that detects whether a wiring is defective based on an image on which a wiring pattern of a wiring board is formed, and includes the three-dimensional contour acquiring device and verification The part verifies the authenticity of the defect detected by the pattern inspection unit based on the three-dimensional contour generated by the three-dimensional contour acquisition device.

One aspect of the present invention provides a method for obtaining a three-dimensional contour, comprising the steps of: an interference forming step of scanning a scanning portion of the interferometer along a direction intersecting the surface to be measured, and having a light source Wide spectrum width of light, separated into measuring beams And the reference beam, the measuring beam is reflected by the surface to be measured, and the reference beam is reflected by the reference mirror, and the first reflected light from the surface to be measured is merged with the second reflected light from the reference mirror to generate an interference grating; The controlling step is such that the light source is flash-off at the same period as the period of the interference grating; and the imaging step is to image the exposure time of the period of the interference grating by the imaging portion of the interferometer The image of the first reflected light and the second reflected light is a plurality of images; and the contour generating step is detected in each pixel of the image based on the plurality of images imaged by the imaging unit The peak position of the interference grating in the scanning direction of the scanning unit generates a three-dimensional contour based on the peak position of each pixel obtained by the detection.

According to the present invention, it is possible to obtain a three-dimensional contour indicating the height distribution of the surface to be measured with relatively simple processing and at a relatively high speed.

11‧‧‧Model test device

12‧‧‧Wiring substrate

12a‧‧‧Measured surface

21‧‧‧3D contour acquisition device

31‧‧‧The type inspection department as an example of the inspection department

32‧‧‧Image Analysis Department

33‧‧‧Verification Department

36‧‧‧Wiring

41‧‧‧A camera as an example of the imaging department

42‧‧‧Interferometer

43‧‧‧Light source

48‧‧‧Half mirror

49‧‧‧ reference mirror

50‧‧‧Actuator

55‧‧‧Scanning Department

56‧‧‧Light sensor

60‧‧‧Control Department

65‧‧‧Lighting control unit constituting one example of the control unit

IF‧‧ interference grating

Te‧‧‧Exposure time

A, B‧‧ ‧ pixels

Za, Zb‧‧·peak position

PD‧‧‧3D contour

Fig. 1 is a perspective view showing a pattern detecting device in an embodiment.

Fig. 2 is a schematic partial cross-sectional view showing a wiring board.

Fig. 3 is a schematic view showing a three-dimensional contour acquisition device.

The schematic diagram shown in Figure 4 illustrates the principle of white light interferometry in a three-dimensional optical unit.

The graph shown in Fig. 5 is an interference grating which is caused by the optical path difference.

Fig. 6 is a perspective view showing a wiring board having a step.

The graph shown in Figure 7 is two pixels on the opposite side of the imaging height. Compare the peak position of the interference grating.

The graph shown in Fig. 8 shows the relationship between the interference waveform, the LED drive waveform, the camera input light waveform, and the camera output.

The graph shown in FIG. 9 shows the relationship between the scanning position, the interference waveform, the LED driving waveform, and the imaging brightness of the camera at the time of measurement.

Fig. 10 (a) is a graph showing the relationship between the interference waveform, the LED drive waveform, the camera input light waveform, and the camera output at one of the scanning positions during the feed scanning and the return scanning, Fig. 10 (b) ) is the chart for the other party.

The flowchart shown in Fig. 11 is a step showing the three-dimensional contour acquisition processing.

In the following, a pattern detecting device including a three-dimensional contour acquiring device (a planar measuring device for measuring a surface) will be described with reference to FIG. 1 to FIG.

As shown in FIG. 1, the pattern detecting device 11 checks whether or not a wiring pattern formed on the wiring substrate 12 is defective. The pattern detecting device 11 includes a support base 13, a movable pedestal 14 provided on the support base 13, a sill-type support frame 15 spanned across the pedestal 14, a rail 16 fixed to the crossbar 15a of the support frame 15, and The wiring substrate 12 can be imaged and suspended to the imaging unit 17 of the track 16. For example, the support base 13 has a rectangular box shape.

The imaging unit 17 includes a high resolution lens 18 and a camera 19. For example, the camera 19 is a face camera. The pattern detecting device 11 performs pattern inspection for checking whether or not there is a defect in the wiring of the wiring substrate 12 based on the image of the wiring substrate 12 imaged by the camera 19. However, the defect detection accuracy of the type inspection has its limit, because This wiring which is detected as a defect candidate by the pattern inspection must verify the authenticity of the defect based on the height distribution information of the wiring substrate 12.

In the pattern detecting device 11 of the present embodiment, the three-dimensional optical unit 20 is mounted in order to perform the above verification. The image formed by the three-dimensional optical unit 20 is used to measure the height distribution of the surface to be measured 12a of the wiring substrate 12.

When the measurement surface 12a is set to the XY plane, the three-dimensional optical unit 20 is formed with a part of the three-dimensional contour acquisition device 21 to obtain a three-dimensional contour ((x, y,) indicating the height distribution of the measured surface 12a. z) Coordinate group). The image formed by the three-dimensional optical unit 20 is used to acquire a three-dimensional contour indicating a height distribution on the surface to be measured 12a (two-dimensional plane) in the inspection target region of the wiring substrate 12.

The pattern detecting device 11 includes, for example, a controller 23 which is provided in the support base 13 and drives and controls each component. The controller 23 is configured to perform, for example, movement control of the pedestal 14, control of pattern inspection by the camera 19, and control of driving of the three-dimensional optical unit 20.

Further, the pattern detecting device 11 includes a computer 25 such as a personal computer. The computer 25 includes a main body 26, an input device 27 composed of a keyboard, a mouse, and the like, and a monitor 28. In a hard disk (not shown) in the main body 26, various programs for performing wiring pattern inspection and defect candidate verification of the wiring substrate 12 are stored. Further, the main body 26 includes an image processing circuit that measures the height distribution of the surface to be measured 12a of the wiring substrate 12 in accordance with the imaged image supplied from the camera 19. The main body 26 includes the inspection unit 31, the image analysis unit 32, the verification unit 33 (calibration unit), and the like shown in FIG. 1 as a functional portion of the CPU and the image processing circuit.

The pattern inspection performed by the inspection unit 31 shown in Fig. 1 is such that the wiring pattern of the wiring substrate 12 is inspected for defects in accordance with the image formed by the camera 19. The inspection unit 31 performs the known processing such as pattern matching processing or delayed self-comparison processing for performing image processing for pattern inspection, and detects defects. The image analysis unit 32 analyzes a plurality of images imaged by the three-dimensional optical unit 20, and calculates a height distribution of the measured surface 12a, thereby generating a height distribution of the measured surface 12a as a three-dimensional coordinate. profile. In addition, the verification unit 33 verifies (verifies) the authenticity of the defect candidate which is suspected in the authenticity based on the three-dimensional contour acquired by the image analysis unit 32 in the inspection by the inspection unit 31.

As shown in FIG. 2, the wiring board 12 includes a substrate 35 and a plurality of wirings 36 formed on the surface 12a to be measured of the substrate 35. Since the density of the wiring 36 is required to be increased, the aspect ratio of the height ratio of the width of the wiring 36 is increased. In the pattern inspection for analyzing the two-dimensional image of the surface to be measured 12a and detecting the defect, as shown in FIG. 2, it is difficult to recognize the oxide film 36a formed on the upper end surface of the wiring 36, the concave portion 36b located at the upper end portion of the wiring 36, The defect portion 36c is half or more of the wire 36 in the height direction. For example, since the oxide film 36a ensures that the electrical impedance of the wiring 36 is equal to or greater than a predetermined value, it is not a defect. Further, if the concave portion 36b is relatively shallow, it will not be regarded as a defect. However, when the concave portion 36b has a certain depth or more, the concave portion 36b causes an increase in the electrical impedance of the wiring 36, which further becomes a defect. On the other hand, the defective portion 36c significantly increases the electrical impedance of the wiring 36, and further becomes a defect. Therefore, in the pattern inspection of the present embodiment, the three-dimensional contour obtained by measuring the height distribution of the surface to be measured 12a by the white light interferometry is used, so that the defect candidates of the oxide film 36a, the recess 36b, and the defect portion 36c which are difficult to recognize can be obtained. Verify its authenticity.

Next, the detailed structure of the three-dimensional contour acquiring device 21 will be described with reference to Fig. 3 .

As shown in FIG. 3, the three-dimensional contour acquisition device 21 includes a three-dimensional optical unit 20 and a control device 40. The control device 40 is constituted by a part of the controller 23 that controls the three-dimensional optical unit 20 and a part of the computer 25 that performs necessary processing in the three-dimensional contour operation.

As shown in FIG. 3, the interferometer 42 included in the three-dimensional optical unit 20 has a camera 41 as an example of an image forming unit. As an example, the interferometer 42 is a Michelson Interferometer. The interferometer 42 includes a light source 43 (for example, a white light source) that emits light having a wide spectral width (for example, a white light source), a collecting lens 44, an optical filter 45, a half mirror 46, a receiver lens 47, and a half The mirror 48, the reference mirror 49, the piezoelectric actuator 50, the imaging lens 51, and the aforementioned camera 41. In the lower portion of the camera 41, a lens barrel 52 having a coaxiality with the optical axis of the camera 41 is provided. In the lens barrel 52, the target lens 47, the half mirror 46, the imaging lens 51, and the half mirror 53 are disposed at predetermined intervals in the optical axis direction.

The light source 43 shown in Fig. 3 includes, for example, an ultra-high luminance LED. The white light emitted from the light source 43 is condensed by the condensing lens 44, and the condensed light is filtered by the optical filter 45 into light of a specific wavelength region (light having a wide spectral width). The filtered light is reflected by the lower surface of the half mirror 46, and is irradiated to the to-be-measured surface 12a of the wiring board 12 by the contact lens 47 and the half mirror 48. Further, the optical filter 45 has a function of adjusting a period (interference possible distance) at which an interference grating is generated to an appropriate value. Moreover, especially when the light emitted by the light source 43 has a relatively wide spectral width, the frequency near the peak of the interference grating will be different from the frequency around the peak. Therefore, the optical filter 45 is disposed in the light source The purpose between the interferometer 42 and the interferometer 42 is to limit the color of the light from the source 43 to some extent such that the frequency of the interference grating approaches a predetermined frequency throughout the region during which it occurs (interferable distance). In particular, the optical filter 45 may be omitted in the case where such adjustment is not required.

The half mirror 48 is disposed between the object lens 47 and the wiring substrate 12, and is framed so as to be movable in the Z direction together with the object lens 47. The position at which the local ray from the objective lens 47 is reflected on the direction in which the upper surface of the half mirror 48 is reflected (leftward in FIG. 3) may be moved along the Z direction together with the half mirror 48. The reference mirror 49 is configured. Further, the reference mirror 49 is supported by a support member 54 fixed to the objective lens 47. The scanning unit 55 is configured such that the objective lens 47, the half mirror 48, and the reference mirror 49 are integrally movable in the Z direction. The scanning unit 55 is formed to be driven by the piezoelectric actuator 50 so as to be in a specified micro stroke along the height direction (Z direction) perpendicular to the measurement surface 12a of the wiring substrate 12 (for example, 20 to 100 μm). Move within the specified value within the range).

The light from the portion of the objective lens 47 is reflected by the half mirror 48 and reflected on the surface 12a of the wiring substrate 12, and the first reflected light from the surface to be measured 12a is again transmitted through the half mirror 48, and is directed from the lower side. The contact lens 47 is incident. In addition, other portions of the light from the upper surface of the half mirror 48 that are reflected from the objective lens 47 are reflected by the reference mirror 49, and the second reflected light from the reference mirror 49 is again reflected by the upper surface of the half mirror 48. The lower side faces the entrance lens 47. The first reflected light and the second reflected light merge on the upper surface of the half mirror 48. The optical path difference between the first and second reflected lights changes depending on the scanning position of the scanning unit 55. When the optical path difference between the first and second reflected lights is equal to or less than a predetermined value At this time, an interference grating (interference fringe) is formed by the first and second reflected lights.

Further, a photo sensor 56 is provided in the three-dimensional optical unit 20 shown in FIG. 3 for receiving the partial first and second reflected lights that are merged on the upper surface of the half mirror 48. The first and second reflected lights of the merged portion are reflected by the lower surface of the half mirror 53 disposed between the imaging lens 51 and the camera 41, and are incident on the photo sensor 56. The received light signal generated by the photo sensor 56 shows a value proportional to the amount of light received. Therefore, when the interference grating occurs, the received light signal of the photo sensor 56 includes a waveform corresponding to the brightness of the interference grating.

The control device 40 shown in FIG. 3 includes the above-described image analysis unit 32, a control unit 60 that controls the three-dimensional optical unit 20, a light-emitting drive unit 61, and a piezoelectric drive unit 62. The control unit 60 includes an imaging control unit 63 that controls the camera 41, an interference monitoring unit 64 that monitors the period and phase of the interference grating based on the received light signal from the photo sensor 56, and an emission control unit 65 that controls the light source 43.

The click-off blinking period of the light source 43 of the present embodiment is the same as the period of the interference grating. Therefore, the light source 43 continues to emit light during the half cycle of the interference grating. When the scanning unit 55 scans and the light source 43 emits light, the interference monitoring unit 64 samples the waveform of the light receiving signal of the photo sensor 56, and at least acquires a phase between the period and the phase of the interference grating. At least the phase of the interference grating IF obtained is transmitted from the interference monitoring unit 64 to the light emission control unit 65.

The illumination control unit 65 shown in FIG. 3 generates an LED driving pulse having a period and a phase matching the period and phase of the interference grating according to the period and phase data of the interference grating or the received light signal from the photo sensor 56. Signal (lighting drive signal), supply to the hair Light drive unit 61. The light emission control unit 65 has, for example, a phase locked loop (PLL). The phase locked loop is based on the period and phase data of the interference grating to produce a pulse signal having the same phase as the phase of the interference grating. Alternatively, during the period in which the interference grating is generated and the light source 43 is illuminated, the phase locked loop is feedback-controlled according to the received light signal of the photo sensor 56 to generate an LED driving pulse signal having a signal from an unillustrated The received light signal of the vibrator performs a phase pulse waveform of the same period. In this case, the light emission control unit 65 generates a half cycle digital LED driving pulse signal according to the half cycle of the light receiving signal during the lighting period of the light source 43 to generate the remaining half cycle LED driving pulse signal, which is generated with the half. The phases of the LED driving pulse signals of the periodic portions are of the same phase.

The light-emitting drive unit 61 generates an LED drive voltage pulse to be supplied to the light source 43 in accordance with the LED drive pulse signal from the light-emission control unit 65. The LED drive voltage pulse has a period and a phase in which the interference grating period and phase are matched. As a result, the light source 43 blinks in the same cycle and phase as the interference grating IF.

Further, in order to scan the scanning unit 55, the piezoelectric driving signal generated by the control unit 60 is defined in accordance with the voltage value applied to the actuator 50. The piezoelectric driving unit 62 supplies (applies) a voltage to the piezoelectric actuator 50 in accordance with the piezoelectric driving signal from the control unit 60. The actuator 50 is configured to laminate a plurality of piezoelectric elements (for example, PZT elements) in a telescopic direction. The actuator 50 is elongated and contracted by the electrostrictive action of the piezoelectric element in accordance with the supplied voltage. The actuator 55 is moved and contracted to move the scanning unit 55 in the Z direction. In the present embodiment, an example of a designated stroke for moving the scanning unit 55 in the Z direction can be set to about 50 μm. Thereby, the so-called specified stroke has a distance far greater than the depth of the recess to be measured in the wiring substrate 12 And the maximum measured length in the Z direction, such as the step height (for example, the height of the wiring 36). Further, in the present embodiment, in the primary height distribution measurement, the scanning unit 55 is moved twice or more (one to one). In this example, the scanning unit 55 is moved twice (one to one).

Further, the imaging control unit 63 shown in FIG. 3 performs imaging control of the camera 41. In such imaging control, the imaging control section 63 controls the exposure time Te when imaging one image, that is, the imaging time interval at the time of imaging one image. The image data imaged by the camera 41 is sequentially transmitted to the image analysis unit 32 of the control device 40. The image analysis unit 32 analyzes a plurality of images imaged by the camera 41, and detects the peak position of the interference grating at each pixel. From the peak position of each pixel, the z coordinate of the pixel corresponding position (x, y) in the surface to be measured 12a is calculated.

Next, the principle of obtaining the height distribution of the surface to be measured 12a will be briefly explained by using the interferometer 42.

As shown in FIG. 4, the light emitted from the light source 43 passes through the condensing lens 44 and the optical filter 45, is reflected downward by the lower surface of the half mirror 46, and is split downward into two beams by the half mirror 48. The partial light (measuring light beam) that has passed through the half mirror 48 is reflected by the surface to be measured 12a of the wiring substrate 12, and is returned to the half mirror 48. On the other hand, the other portion of the light (reference beam) reflected by the upper surface of the half mirror 48 is reflected by the reference mirror 49 and returned to the half mirror 48. The measuring beam of the distinct optical path merges with the reference beam above the half mirror 48. In the scanning unit 55, there is a certain distance Zm between the half mirror 48 and the reference mirror 49 (hereinafter also referred to as "reference distance Zm"), and the distance Zs between the half mirror 48 and the surface to be measured 12a ( Hereinafter, it is also called "measuring distance Zs".) The change is made in accordance with the scanning of the scanning unit 55 in the Z direction. The optical path difference of the two reflected lights scanned by the scanning unit 55 is formed to be 2 (Zs - Zm).

In the present embodiment, the white light that has passed through the optical filter 45 has a wide spectral width. Therefore, the measuring beam and the reference beam are such that only the optical path difference 2 (Zs-Zm) between the interfering measuring beam and the reference beam is formed to a minimum range (Zs ≒ Zm) below a predetermined value. With such characteristics, the control unit 60 causes the scanning unit 55 to scan in the Z direction so that the optical path difference 2 (Zs-Zm) changes. The image analyzing unit 32 is a scanning position (Z when Zs=Zm) occurs when Zs≒Zm and the occurrence of the occurrence of the interference grating occur in a plurality of images. Position), and each pixel is obtained as a peak position. At this time, the color of the light from the light source 43 is somewhat limited by the optical filter 45, and the frequency of the interference grating is adjusted to be slightly constant in the entire region during the occurrence of the interference grating (interference distance). shape. The imaging range of the camera 41 in the measurement surface 12a of the wiring substrate 12 is known from the known information such as the position (X, Y) of the three-dimensional optical unit 20 in the X direction and the Y direction, and the magnification of the camera 41. . The pixel within the imaging range can correspond to the position on the surface to be measured 12a within the imaging range. The image analysis unit 32 obtains a height (z coordinate) distribution of a plurality of positions (x, y) in the measurement target surface 12a corresponding to each of the plurality of pixels, based on the Z position of the plurality of pixels of the camera 41 (x). , y, z) three-dimensional outline.

Figure 5 shows the relationship between the optical path difference and the brightness of each pixel. As shown in the graph, when the optical path difference (=2 (Zs - Zm)) is formed within a range equal to or less than a predetermined predetermined value (interference possible distance Lf), the interference grating IF is generated. The amplitude of the luminance waveform of each pixel changes according to the optical path difference. When the optical path difference is zero (that is, Zs=Zm), the wave of the interference grating IF The peak forms the largest.

In the present embodiment, for example, the reference distance Zm is matched with the focal length of the objective lens 47. When the focal point of the objective lens 47 and the surface to be measured 12a of the wiring substrate 12 (for example, the upper surface of the wiring 36 which is free of defects) are combined, the measurement distance Zs and the reference distance Zm almost coincide with each other, and the interference grating IF appears. Thereby, the scanning unit 55 moves the focus of the objective lens 47 by only a certain distance, which is, for example, a designated stroke when the position to be measured is the center of the surface to be measured 12a (for example, 50 μm).

As an example, as shown in FIG. 6, a case where the Z-direction position (height) of the wiring substrate 12 having the step 12b is measured will be described. For example, the wiring substrate 12 is a low surface PA and a high surface PB having a step 12b interposed therebetween.

As shown in FIG. 7, when the difference between the measured distance Zs between the half mirror 48 and the low surface PA and the reference distance Zm is twice the optical path difference 2 (Zs-Zm) shown in the prescribed range, In the case of the light of the low-surface PA (referred to as "pixel A" in Fig. 7) among the plurality of pixels in which the camera 41 is imaged, the interference grating IF appears. Therefore, in the generation region of the interference grating IF, the brightness of the light abutting on the pixel A changes in accordance with the scanning position. At this time, the interference grating IF does not appear in the light of the pixel (referred to as "pixel B" in Fig. 7) of the high-surface PB in the plurality of pixels on which the camera 41 is imaged.

Further, when the optical path difference 2 (Zs-Zm) indicated by the difference between the measured distance Zs between the half mirror 48 and the high surface PB and the reference distance Zm is formed within a prescribed range, the image is abutted The light of the pixel B of the high side PB will appear as an interference grating IF. Therefore, in the generation region of the interference grating IF, the brightness of the light abutting the pixel B will correspond to the scanning position. And change. At this time, the interference grating IF does not appear at the light that abuts the pixel A of the imaging low surface PA.

The scanning position Za of the scanning portion 55 when the interference grating IF appears in the light abutting the pixel A, and the distance 2 Δ between the scanning position Zb of the scanning portion 55 when the interference grating IF appears in the light abutting the pixel B Z is twice the height ΔZ of the step 12b. To determine the peak positions Za and Zb in the Z direction of the interference grating that abuts the light of each of the pixels A and B, the distance between the two peak positions Za and Zb can be set to 1/2 of the distance ΔZ. It is obtained with respect to the height ΔZ of the surface PB of the surface PA.

However, in the sampling method in which the interference grating is described in Patent Document 2, in the sampling method of performing the complex point in each cycle, in order to obtain the peak of the interference grating, the interference grating IF pitch is at least 1/3 or In the sampling of 1/4 of 100 nm (nano) or less, it is necessary to obtain a large number of images. In this case, in the case where image data is acquired within a range of 50 μm of the movement stroke of the scanning unit 55, it is necessary to have 500 or more images. In this case, although the accuracy of the nanometer (nm) level can be obtained, it will be very time consuming in the imaging operation, and the required memory size will be quite large. In addition, the peak position of each pixel is calculated. The processing time will also become quite long and not practical. Further, in the sampling step of 100 nm or less in scanning the scanning unit 55 in the Z direction, it is difficult to suppress the vibration in the exposure time caused by obtaining a fine and large image, and it is also difficult. It is mounted to the pattern detecting device 11. On the other hand, when the imaging speed of the camera 41 is increased, and the influence of the vibration is to be alleviated, the image is darkened and the peak position detection accuracy is lowered.

On the other hand, the shortage of the wiring substrate 12 performed in the pattern detecting device 11 In terms of verification, there is no need for a nanometer (nm) level, and the accuracy of the 100 nm level is sufficient. Therefore, it is preferable to increase the exposure time by reducing the number of images to be imaged. However, since the interference grating IF has a waveform that periodically appears in the bright portion and the dark portion, when the light source 43 is continuously emitted, and the pixel of the camera 41 receives light at a certain exposure time Te of the period of the interference grating IF or more, The bright portion and the dark portion of the interference grating IF that causes the light that abuts each pixel are averaged. This will make it difficult to detect the peak of the interference grating IF.

Here, as shown in FIG. 8, in the present embodiment, the light source 43 is made to have the same period (in other words, the same frequency) and phase as the waveform of the interference grating IF (hereinafter also referred to as "interference waveform"). LED) flashes off. For example, the selective imaging of the camera 41 corresponds to the bright portion during the lighting of the light source 43 in the interference waveform (in FIG. 8, the portion located further on the upper side than the center line of the input light waveform). In the example of Fig. 8, the waveform of the light incident on each pixel of the camera 41 is approximately equivalent to the waveform of the bright portion selected at the exposure time Te. Therefore, the luminance value of the output of the pixel of the camera 41 (the camera output in FIG. 8) corresponds to the integrated value (integral value) of the amount of light received by the pixel between the exposure times Te. In the example of Fig. 8, the luminance value of the pixel corresponding to the image that has been imaged has a value corresponding to the amount of received light of the selective integrated portion. In this case, since the amount of light of the input light of the camera 41 when the light source 43 is turned off is often maintained at a very low constant value, the camera output value (the luminance value of the pixel as the integral value of the amount of received light of the pixel in the exposure time Te) ) is almost proportional to the height of the envelope EV of the interference grating IF (the two-point chain line in Fig. 5). The image analysis unit 32 performs an interpolation calculation between two luminance values of pixels corresponding to the different images according to the plurality of images, and calculates a complex number placed on the envelope EV with a positional accuracy smaller than the imaging interval. The luminance value, by which the peak position of the envelope EV is calculated to obtain the interference grating I The peak position of F. In addition, in FIG. 8, the camera output value (luminance value) is shown by a dot, and the time change of the pixel light-receiving amount of the camera 41 between exposure time Te is shown by the solid line.

Further, as shown in FIG. 8, the LED driving waveform in which the light source 43 (LED) is set is an exposure time Te of one cycle or more. For example, the exposure time Te is set to a multiple of the natural number of one cycle of the LED drive waveform. In the example of FIG. 8, the exposure time Te is equivalent to one cycle of the LED drive waveform. Of course, it is not limited to this, and the exposure time Te may be set to a multiple of the natural number of the light source 43 click-off period. For example, the exposure time Te may be 2 or 3 times the period of the LED drive waveform. Further, since the exposure time is increased without requiring special processing, when the scanning portion 55 is moved in the section where the interference distance Lf of the interference grating IF occurs, the value of the set exposure time Te is desirably three or more images that can be imaged. image. That is, it is preferable to set the exposure time Te to a value within a range of 1/4 to 1/3 of the period during which the interference grating IF is generated (in other words, the time for scanning the interferenceable distance Lf). Of course, the exposure time Te can also be set such that when the peak of the interference grating IF can be detected, it exceeds a value of 1/3 of the period during which the interference grating IF occurs. In this case, it is also possible to use an operation (wave peak detection analysis process or the like) in which the peak detection of the interference grating is performed and the exposure time Te is set to be as long as possible. For example, when the required accuracy is not so high, the exposure time Te above the period during which the interference grating IF is generated may be set.

However, in the example shown in FIG. 8, although the bright portion of the interference waveform and the LED driving waveform are almost coincident, and the phase of the interference waveform is almost the same as the phase of the LED driving waveform, there is still a limitation in control. This causes a phase shift. For example, as shown in FIG. 10(a), when the phase of the LED driving waveform is shifted by about 90 degrees with respect to the phase of the interference waveform, the lighting period of the LED driving waveform during the exposure time Te is In the middle, there are slightly more than half of the interference waveform in the bright and dark portions of the camera input light waveform. In this case, even if the amplitudes of the waveforms are different, since the difference from the center of the amplitude of the bright portion is approximately equal to the difference from the center of the amplitude of the dark portion, the bright and dark portions are averaged. The amount of light received in the exposure time Te between the corresponding pixels in the plurality of images imaged by the camera 41 will not be different. As a result, it is difficult to calculate the peak position of the interference grating IF by the luminance value of each pixel of the camera 41. Here, in the present embodiment, the following control is employed.

The graph shown in FIG. 9 sequentially displays the scanning position (Z position) of the scanning unit 55, the interference waveform in the pixels of the camera 41, the LED driving waveform, and the camera imaging luminance (camera output). The luminance value indicated by the camera imaging luminance is the amount of light received by the camera 41 in response to the measurement (imaging). As shown in FIG. 9, the scanning unit 55 performs one-to-one scanning for one measurement area. The light emission control unit 65 shifts only the phase of the LED drive waveform by 90 degrees during the feed motion process and the return motion process. In the feed scanning process in which the scanning portion 55 is moved from the origin (position 0 μm) as the scanning start position to the scanning upper limit position Zo (position 50 μm), the phase of the LED driving waveform forms a preset phase, and is returned to the scanning process. The phase of the LED drive waveform is formed such that the phase of the feed scanning process is shifted by 90 degrees.

For example, in the feed scan process as shown in FIG. 10(a), if the phase between the interference waveform and the LED drive waveform is shifted by about 90 degrees, it is difficult to perform the peak of the interference grating IF as described above. The calculation of the position. Even in this case, in the return scanning process shown in FIG. 10(b), the phase between the interference waveform and the LED driving waveform is formed to be the same, and since only the bright portion in the exposure time Te is accumulated, According to the luminance value of the pixel The calculation of the peak position of the interfering grating IF. As described above, at the time of feeding and returning of the scanning unit 55, by shifting the light source 43 by blinking, the phase is shifted by 90 degrees, and the peak position of the interference grating IF at least one of the feed timing and the return timing can be calculated. Here, the image analysis unit 32 is configured to use the luminance values of the pixels in the plurality of images imaged by the camera 41 in the scanning of the scanning unit 55, and the two luminance values of the corresponding pixels in the different images. Interpolation calculations are performed to calculate the peak position of the envelope EV of the interference grating IF. Further, the peak position detecting process of the interference grating of each pixel by the image analyzing unit 32 is performed at a high speed by the image processing circuit in the computer 25.

Next, the roles of the pattern detecting device 11 and the three-dimensional contour acquiring device 21 will be described.

First, pattern inspection is performed on all the wirings 36 that have been formed on the wiring substrate 12. The inspection unit 31 performs pattern inspection based on the image of the surface to be measured 12a imaged by the camera 19 of the image forming unit 17, and when detecting a defect candidate having doubts about authenticity, it is required to perform verification processing. For example, the oxide film 36a, the recessed portion 36b, and the defective portion 36c on the wiring 36 shown in FIG. 2 are detected as defect candidates in the pattern inspection, and are verified. The control unit 60 that receives the verification request command moves the pedestal 14 at a position in the X direction in which the defect candidate can be imaged, and moves the three-dimensional optical unit 20 at a position in the Y direction in which the defect candidate can be imaged.

When the light source 43 is caused to emit light before the start of scanning, the calibration operation is performed so that the scanning unit 55 performs at least one scanning, and the phase is obtained based on at least the period and phase of the interference grating according to the received light signal of the photo sensor 56. . With this calibration operation, the phase of the interference grating with respect to the scanning position of the scanning unit 55 is obtained.

The control device 40 is a three-dimensional contour acquisition processing routine implemented in FIG. Program. Hereinafter, the three-dimensional contour acquisition processing routine will be described based on the flowchart of FIG. Further, in the processing of FIG. 11, control by the control unit 60 in the controller 23, and image analysis by the light emission control of the light source 43, the scanning control of the scanner unit 55, and the imaging control of the camera 41 are included. The processing performed by the unit 32. Further, in the control performed by the control unit 60, the partial processing or the entire processing can be performed by the computer 25. Further, an image analysis unit 32 may be provided in the controller 23.

In step S1, the scanning unit 55 is caused to perform a feed motion. In other words, the control unit 60 supplies the piezoelectric driving signal to the piezoelectric driving unit 62, and changes the voltage applied to the actuator 50 to cause the scanning unit 55 to be scanned at a certain speed (origin). The position is 0 μm) to the end position of scanning (position 50 μm) for the feed motion.

In step S2, the light source is caused to blink at the same period as the period of the interference grating. That is, the light emission control unit 65 generates an LED drive pulse signal of the same period as the period of the interference grating IF, supplies the pulse signal to the light emission drive unit 61, and applies a pulse voltage to the light source 43, thereby causing the light source 43 to interact with the interference grating. The period of the IF is blinking for the same period.

In step S3, the surface to be measured 12a is imaged by the camera at an exposure time which is a multiple of the natural number of the period of the interference grating. That is, the imaging control unit 63 performs imaging at each exposure time Te in the camera 41. The image data imaged by the camera 41 is sequentially transmitted to the image analyzing unit 32.

In the next step S4, a plurality of images are analyzed, and the Z position at which the peak of the interference grating appears is detected for each pixel. In other words, the image analysis unit 32 stores the luminance of the pixel on the surface to be measured 12a when the interference grating is not displayed as the reference luminance value. Save to memory. On the other hand, the image analysis unit 32 calculates the difference ΔB between the luminance value and the reference luminance value in each pixel of the image data, and sequentially stores the difference ΔB of each pixel in the memory. On the other hand, the image analysis unit 32 performs the interpolation calculation using the difference ΔB of each of the plurality of pixels, and is respectively at a position (scanning position) where the imaging interval moved by the scanning unit 55 between the one imaging is narrow. The difference on the envelope EV (see FIG. 5) of the interference grating IF of each pixel is successively obtained. The image analysis unit 32 sequentially compares the difference on the envelope EV, and detects the scanning position at the maximum value as the peak position (Z position).

In the appearance section of the interference grating IF, since the waveform of the interference grating is included in the received light signal during the lighting period of the photo sensor 56, the interference monitoring unit 64 can detect the period and phase of the interference grating. The light emission control unit 65 generates an LED drive pulse signal according to the received light signal of the light sensor 56 and the phase of the interference grating. Therefore, in the generation section of the interference grating IF, the phase of the click-off waveform of the light source 43 is aligned with the phase of the interference grating, and a relatively large difference ΔB is obtained, thereby improving the peak position detection sensitivity.

It is determined in step S5 whether or not the feed motion of the scanning portion has been ended. The control unit 60 is configured to determine whether the value of the piezoelectric driving signal has reached a value when the scanning unit 55 only ends the movement of the designated stroke (for example, 50 μm) and is located at the scanning upper limit position Zo. If it is before the end of the feeding operation of the scanning unit 55, the process returns to step S3, and the imaging process of step S3 and the peak position detection process by the image analysis of step S4 are repeated until the feed motion is determined in step S5. End it.

For example, when the measurement surface 12a of the wiring substrate 12 shown in FIG. 6 is measured, during the feeding movement of the scanning portion 55, in the scanning position Za shown in FIG. 7, the low surface is abutted. The peak of the interference grating IF appears in the light of the pixel A of the PA, in the scanning bit In Zb, the peak of the interference grating IF appears in the light of the pixel B abutting on the imaging high plane PB. Therefore, in step S4, two peak positions Za and Zb corresponding to the heights of the two faces PA and PB on the surface to be measured 12a are detected. On the other hand, when the feeding motion of the scanning unit 55 is ended, the process proceeds to step S6.

In step S6, the scanner unit 55 is caused to perform a return operation. That is, the control unit 60 supplies the piezoelectric driving signal to the piezoelectric driving portion 62, and by changing the voltage applied to the actuator 50 to be reversed at the time of feeding, the scanning portion 55 is caused by the scanning speed at a certain speed. The scanning end position (position 50 μm) is returned to the scanning start position (origin = position 0 μm).

In step S7, the light source is caused to blink at a phase different from the interference grating and different from the scanning unit 55 by 90 degrees. That is, the interference grating period monitored by the previous interference monitoring unit 64 is known, and the LED driving is performed by shifting the output time point of the LED driving pulse signal by 1/4 cycle for the output time point when the scanning portion 55 is fed. The phase of the pulse signal is shifted by 90 degrees with respect to the feed, and the output time point of the LED drive pulse signal is generated by the light emission control unit 65 with respect to the scanning position of the scanning unit 55. Then, the LED driving pulse signal having the same period of the interference grating IF period shifted by 90 degrees from the phase is supplied to the light-emitting driving portion 61 so as to be the same period as the interference grating IF period and when the scanning portion 55 is fed. The 90 degree phase is different, causing the light source 43 to flash off.

The respective processes of the subsequent steps S8 and S9 are the same processes as the respective processes of steps S2 and S3. That is, in step S8, the surface to be measured 12a is imaged by a camera at an exposure time which is a multiple of the natural number of the interference grating period. The image data imaged by the camera 41 is sequentially transmitted to the image analysis unit 32. And in step S9, the plurality of images are analyzed, and the Z of the peak of the existing interference grating is detected in each pixel. position.

In step S10, it is determined whether or not the return movement of the scanning unit has ended. That is, the control unit 60 determines whether or not the value of the piezoelectric driving signal has reached the value when the scanning unit 55 is at the scanning start position. If the return motion of the scanning unit 55 is before the end, the process returns to step S8, and the peak position detection processing by the imaging processing of step S8 and the image analysis of S9 is repeatedly performed until the end of the return motion is determined in step S10. until. When the return movement of the scanning unit 55 is completed, the process proceeds to step S11. For example, at the time of the feeding and returning of the scanning unit 55, even if the phase of the click-off waveform of the light source 43 is slightly shifted by 90 degrees with respect to the phase of the interference grating IF, on the other hand, with respect to the interference grating IF The phase of the click-off waveform of the light source 43 is formed to be slightly uniform or slightly offset by 180 degrees. Therefore, when scanning is performed on the other side, the peak position (Z position) of the envelope EV of the interference grating IF can be detected based on the difference ΔB.

In step S11, a three-dimensional contour is generated in accordance with the Z position detected by each pixel. In other words, the image analysis unit 32 uses a peak having a larger peak as the peak detected when the scanning unit 55 is fed and the peak detected when the scanning unit 55 returns. Z position. In this case, it is also possible to compare the peaks at the time of the feed and the peaks at the time of return to the local pixels in the entire pixel, and determine whether or not the adopted peak position has been detected when the scanning unit 55 is fed, or has It is detected at the time of return, and the peak position of the judgment side is used. When determining the Z position of each pixel to be employed, the three-dimensional contour PD is generated in accordance with the z coordinate of the Z position.

In this manner, when the three-dimensional contour PD in which each pixel is represented by a coordinate (x, y, z) is generated, the three-dimensional contour PD is transmitted to the verification unit 33. The verification section 33 is composed of a three-dimensional contour P D obtains the height distribution of the defect surface with doubts about authenticity, and verifies the authenticity of the defect based on the height. For example, in the case of the oxide film 36a shown in FIG. 2, since the height of the upper surface of the wiring 36 has exceeded a predetermined height, the defect verification is negative. In the case of the recess 36b as shown in FIG. 2, if the height of the upper surface of the wiring 36 has exceeded a predetermined height, the defect verification is negative, and if the predetermined height is not reached, the defect verification is affirmative. Further, in the case of the defective portion 36c shown in Fig. 2, since the height of the upper surface of the wiring 36 is less than the predetermined height, it is verified as affirmation in the defect verification.

Further, the calculation of the peak position of the interference grating of each pixel is detected based on the plurality of images in steps S4 and S9, and the imaging by the camera 41 may be performed in the scanning of the scanning unit 55 in step S10 (in step S10). In the affirmative judgment, the whole number is finished. That is, in the above example, the calculation processing of the peak position is performed in the imaging of the outward and return paths of the scanning unit 55. However, in the outbound and backhaul of the scanning unit 55, after the full imaging by the camera 41 is completed, the respective pixels are calculated in the forward and the return according to the plurality of images stored in the memory so far. The peak position of the interference grating can be used to detect the peak position of each pixel in the forward and return strokes of the same pixel.

As described in detail above, according to the first embodiment, the following effects can be obtained.

(1) The light source 43 is blinked to be synchronized with the period of the interference grating IF generated by the interferometer 42. Therefore, when the camera 41 images the image of the reflected light passing through the interferometer 42 at an exposure time Te of the interference grating IF period or more, the light of the interference grating is every half cycle, that is, during the lighting of the light source 43. Within, it abuts the pixels of the camera 41. Therefore, the pixel of the camera 41 is such that the interference grating IF is every half cycle. The way of the period is to receive light. At this time, for example, only the bright portion of the interference grating IF is imaged, or only the dark portion thereof is imaged. As a result, the pixel of the image data has a luminance value reflecting the envelope EV of the interference grating IF, and the image analyzing unit 32 can detect the peak position of the interference grating IF in each pixel based on the plurality of images. Thereby, the image analysis unit 32 obtains the height distribution of the surface to be measured 12a from the peak position of the interference grating IF measured in each pixel, and generates the three-dimensional contour PD.

(2) The scanning unit 55 is reciprocally scanned to cause the light source 43 to blink at the time of feeding and returning of the scanning unit 55, and to shift the phase by about 90 degrees, thereby at least at the time of feeding and returning. Either side, the peak position of the interference grating IF can be detected. For example, even if the phase between the light source 43 and the interference grating are not closely aligned, the peak position of the interference grating IF can be detected in each pixel, and the three-dimensional contour PD can be generated. Further, the three-dimensional contour PD can be generated with higher precision than the configuration in which the scanning portion 55 is scanned only once.

(3) The optical sensor 56 is configured to receive the reflected light partially passing through the interferometer 42. According to the received signal of the photo sensor 56, the phase of the interference grating IF can be used to flash the light source 43. . Therefore, it is possible to reduce the detection of the peak position of the interference grating IF caused by the averaging of the bright portion and the dark portion of the interference grating IF during the exposure time Te at the time of imaging.

(4) The value set by the exposure time Te of the camera 41 is within a range of 1/4 to 1/3 of the period during which the interference grating IF is determined by the scanning speed of the scanning unit 55. Therefore, the peak position of the interference grating IF can be detected by using a smaller number of patterns of one-tenth to one-tenth of a degree, for example, in the case of detecting a peak by a sampling method. In addition, The memory size required for image data storage can also be solved with less capacity. In addition, the image analysis unit 32 does not need to use a plurality of images to perform special processing such as peak position detection processing (complex peak detection analysis processing, etc.), and it is only necessary to perform simple processing. Since the method can be solved, the image analysis unit 32 can speed up the acquisition process of the three-dimensional contour PD.

(5) The three-dimensional contour acquisition device 21 is applied to the pattern detecting device 11, and the authenticity of the defect candidate detected by the pattern inspection of the wiring substrate 12 is verified by the verification portion 33 in accordance with the three-dimensional contour acquisition device 21. The contour PD is used for verification. As a result, in the inspection of the wiring substrate 12 including the wiring 36 having a high aspect ratio due to the demand for miniaturization of the wiring 36, it is possible to accurately detect defects due to insufficient height of the wiring 36.

(6) The dot-off blinking period of the light source 43 is set to be the same as the period of the interference grating IF. Therefore, according to the light receiving signal of the photo sensor 56 in the scanning operation of the scanning unit 55, the waveform can be detected every half period of the interference grating IF, and the phase of the LED driving pulse signal can be adjusted to match the interference grating IF. The phase. Therefore, the peak detection sensitivity of the interference grating IF is improved, and a high-precision three-dimensional contour PD can be obtained. For example, the verification accuracy of the defect candidate by the verification unit 33 can be improved.

The embodiment is not limited to the above-described aspect, and may be changed to the following state.

. In the above embodiment, the scanning unit 55 is reciprocated in the Z direction perpendicular to the surface to be measured 12a, but it is also possible to perform one-way scanning with only a feed motion or only a return motion. For example, when the phase-locked loop in the light-emission control unit 65 of the light-receiving signal input to the photosensor 56 outputs an LED drive pulse signal having the same phase as the phase of the interference grating, even one-way of the scanning unit 55 Scan, still get the necessary essence The three-dimensional contour of the degree PD. Further, when the phase information of the interference grating IF obtained by the sampling of the waveform of the interference grating is corrected by the photo sensor 56 and the interference monitoring unit 64, only the scanning unit 55 can correct the phase of the LED driving waveform. In one scan, the peak position of the interference grating IF can be detected with better precision, and a three-dimensional contour PD having a certain degree of precision can be obtained.

. The number of scans of the scanning unit 55 when measuring the height distribution of the same area of the measurement surface is not limited to one round-trip motion (two scans), but may be one-to-five round trips (three scans), plural Round trips (for even scans of more than four times) or odd scans of five or more times. In such cases, it is preferred to slightly shift the phase of the different feed motion or the return motion, and the phase that has been offset includes at least one offset by 90 degrees. The phase is better. Of course, it is also possible to configure a phase that does not shift the blinking of the light source 43.

. The photo sensor 56 and the interference monitoring unit 64 may not be provided. Even in such a configuration, when the phase of the blinking of the light source 43 is changed by 90 degrees during the feeding and returning of the scanning unit 55, since the peak position of the interference grating IF can be detected, a three-dimensional contour can be generated.

. The light source 43 is not limited to white light as long as it emits light having a wide spectral width. As long as the spectrum from the light source has a certain width and the interference grating IF can be generated in a range in which the optical path difference is narrow, and it can be used for white light interference. Further, the light source 43 is not limited to an LED, and may be a bulb, an organic EL illuminator, or a fluorescent lamp. In addition, the light of the light source 43 may partially include infrared light or ultraviolet light that can be received by the camera 41.

. The light source 43 is fitted to the dark portion of the interference grating, and the phase of the illumination is blinked, and the peak position of the interference grating may be obtained based on the luminance value obtained by integrating the dark portion of the interference grating.

. The angle of the blinking phase of the offset light source 43 at the time of the feed scanning and the return scanning is not limited to only 90 degrees, and may be set to other angles. For example, it is better to use a value in the range of 80 to 100 degrees, but even if the angle is shifted by a small angle, the peak position detection accuracy can be improved by the motion of either the feed motion or the return motion. Further, in the case of shifting the phase, the phase at the time of return with respect to the feeding of the scanning portion 55 can be advanced or delayed. Even in such a configuration, the scanning unit 55 can reliably detect the peak position of the interference grating by at least one of the feeding and returning.

. The configuration of controlling the phase of the phase when the light source 43 is turned off and the interference grating may not be performed. The detection of the peak position of the interference grating can be performed even without phase control.

. A Miruau interferometer can also be used instead of a Mikeson interferometer, which mounts a very small reference mirror (mirror) on the center surface of the lens, and places the half mirror on the way to the focal plane. Interfering with light from the surface being measured and reflected light from a reference mirror on the lens.

. At least a part of the control unit 60 may be formed of a soft body, a hard body, or a combination of a soft body and a hardware. The image analyzing unit 32 may be configured by software or may be configured by cooperation between a software and a hardware.

. The wiring board 12 may be a wiring board on which a wiring pattern such as a package, a TAB tape, or an IC chip is implemented, or a wiring board for a flat panel display. For example, it can also be liquid crystal Flat panel wiring board for display, organic electroluminescence (organic EL), and plasma display. Further, the wiring board may be a glass wiring board or a plastic wiring board. The type of the surface to be inspected to be inspected is not limited to the wiring 36, and may be a bump. The pattern detecting device 11 can be used to inspect the bump pattern of the wiring board.

. The three-dimensional contour acquisition device is not limited to being applied to the pattern detecting device. The measurement target is not limited to the wiring substrate, and any one of the concave surface, the convex portion, and the step of the measurement surface may be used as the inspection target. In this case, the inspection may be performed to treat the object whose fine recess or convex portion does not reach the specified depth or height as a defect, or to check whether there is a fine recess or convex portion where it should be a flat surface. Inspection of defects. Further, it is also possible to use the foreign matter inspection as described in Patent Document 1, or the perforation inspection as described in Patent Document 2. Furthermore, it can also be applied to a built-in wafer bump detecting device for inspecting the height or volume of microbumps on a semiconductor wafer. It can also be applied to the FC bump detecting device for checking the height or volume of the bump of a single-chip or frame-shaped IC package mounted on a bump of a flip chip (FC). In addition, it can also be applied to a laminated substrate plating thickness monitoring device for monitoring the plating thickness of a two-dimensional type of a laminated substrate. Further, it is also applicable to a high-precision printing monitoring device that performs precise monitoring, feedback soldering, or coating thickness (printing thickness) of conductive ink.

. The object to be measured by the three-dimensional contour acquisition device is not limited to an electronic component such as a wiring board, and may be any material that requires precise measurement and detection of the height distribution. For example, the height distribution in MEMS (Micro Electro Mechanical Systems) can also be measured. For example, a micromachine, a display device, a sensor, and an actuator can be applied as measurement targets. Furthermore, management of the micro-groove depth in the biochip (eg, DNA wafer) to achieve sensor function can also be performed. In addition, the so-called crimping of the original to the base The plate and the nanoimprint which realizes microfabrication by transfer can also be applied to the high-speed and precise detection of the transfer fine structure. In addition, it can also be applied to optical communication devices or depth distribution inspections such as optical ICs and optical waveguides.

11‧‧‧Model test device

12‧‧‧Wiring substrate

12a‧‧‧Measured surface

21‧‧‧3D contour acquisition device

31‧‧‧Inspection Department

32‧‧‧Image Analysis Department

33‧‧‧Verification Department

Claims (6)

A three-dimensional contour acquiring device comprising: a light source having a wide spectral width; and an interferometer including a scanning unit and an imaging unit, wherein the scanning unit is configured to be along the opposite measuring surface Scanning in the intersecting direction, the scanning unit separates the light from the light source into a measuring beam and a reference beam, and the measuring surface reflects the measuring beam, and the reference beam is reflected by the reference mirror to obtain the surface to be measured. The first reflected light merges with the second reflected light from the reference mirror to generate an interference grating, and the imaging portion images the first reflected light and the second reflection by an exposure time of a period equal to or longer than the period of the interference grating The image of the light is a plurality of images, and the control unit controls the scanning unit to scan in a direction intersecting the surface to be measured, and to control the period of the light source and the interference grating to be the same period. And an image analysis unit that is respectively based on the plurality of images imaged by the image forming unit The pixels detect the peak position of the interference grating in the scanning direction of the scanning portion, and generate a three-dimensional contour according to the detected peak position of each pixel. The three-dimensional contour acquiring device according to claim 1, wherein the control unit is configured to reciprocate the scanning unit in a direction intersecting the measurement surface, and to cause the light source to be fed and returned when the scanning unit is driven. Between the two, the phase of the aforementioned light source is turned off. The three-dimensional contour acquisition device according to claim 1 or claim 2, wherein the three-dimensional contour acquisition device further includes a photosensor that receives the first reflected light and the second reflection partially directed toward the imaging portion. Light, which produces the first reflected light and the second And a light receiving signal of the partial light receiving amount of the reflected light; the control unit causes the light source to blink at the same phase as the interference grating based on the received light signal of the light sensor. The three-dimensional contour acquiring device according to claim 1 or claim 2, wherein the exposure time of the image forming unit is set to a value within a range of 1/4 to 1/3 of a period in which the interference grating is generated. A pattern detecting device including a pattern inspection unit that detects whether or not a wiring is defective based on an image on which a wiring pattern of a wiring board is imaged, and is characterized by including the item 1 or the request item 2 The three-dimensional contour acquisition device; and a verification unit that verifies the authenticity of the defect detected by the pattern inspection unit based on the three-dimensional contour generated by the three-dimensional contour acquisition device. A method for obtaining a three-dimensional contour, comprising: an interference forming step of scanning a scanning portion of the interferometer along a direction intersecting the surface to be measured, and emitting light having a wider spectral width by the light source, Separating into a measurement beam and a reference beam, and reflecting the measurement beam by the measurement surface, and reflecting the reference beam by a reference mirror, and merging the first reflected light from the surface to be measured with the second reflected light from the reference mirror Generating an interference grating; the illuminating control step is such that the light source is flash-off at a period equal to the period of the interference grating; and the imaging step is performed by the imaging portion of the interferometer in an exposure time above a period of the interference grating And imaging the image of the first reflected light and the second reflected light into a plurality of images; the contour generating step is based on the plurality of images imaged by the imaging unit, respectively In each pixel of the image, a peak position of the interference grating in the scanning direction of the scanning portion is detected, and a three-dimensional contour is generated according to the detected peak position of each pixel obtained by the detection.