JPH03231105A - Method and apparatus for appearance inspection of soldered part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soldering part appearance inspection method and apparatus for inspecting a soldered part of a printed circuit board or the like.

[Conventional technology]

As a conventional appearance inspection device for soldered parts, there is a
A device such as that shown in Japanese Patent No.-60593 has been known. In this method, a dot-shaped spot is illuminated on the soldered part, and the optical cutting line of the soldered part is extracted by scanning this spot.

With this method, the cross-sectional shape of the solder can be measured regardless of the condition of the solder surface, so there is no need for solder.

Defects such as excessive solder can be inspected.

Also, in JP-A-61-121022.

A device that can measure three-dimensional shapes using a confocal optical system has been introduced. This method is based on the light intensity signal detected by scanning the light beam in the x and y force directions in a plane perpendicular to the traveling direction.
A dimensional image is created, and the stage on which the sample is placed is scanned in the Z direction to find the Z value that maximizes the detected light intensity for each (x, y) coordinate. It detects the directional profile.

[Problem to be solved by the invention]

In the former conventional technique, since only the cross-sectional shape of the solder surface is used, the amount of solder cannot be measured, and there is a problem in that it is not possible to accurately evaluate whether there is too much or too little solder.

Furthermore, the latter conventional technique is a microscope that takes advantage of the high resolution of a confocal optical system, and therefore has the problem of a small measurement range. Since the solder surface is close to a mirror surface, the reflected light may not return to the detector depending on the angle of the measurement surface, and depending on the angle, almost 100% of the reflected light may return to the detector. Therefore, there was a problem in that the detector required a dynamic range of several orders of magnitude.

The purpose of the present invention is to solve the above problems by determining the three-dimensional shape of soldered parts and inspecting defects such as no solder, too much or too little solder, and short circuits in soldered parts at high speed and with high reliability. An object of the present invention is to provide a method and apparatus for visually inspecting a soldered part.

[Means to solve the problem]

In order to achieve the above object, the present invention places a board having a soldering part on a stage, and directs a minute spot of linearly polarized light (a minute spot laser beam of linearly polarized light) onto the soldering part. The light is irradiated through the objective lens while scanning dimensionally, and among the light reflected from the surface of the soldering part,
The specularly reflected light image formed through the objective lens is blocked by a polarizing element, the scattered light image is received by a photoelectric conversion means and detected as a signal, and the minute spot light is relatively moved in the height direction. The height value Z at which the above signal is maximum
Find (x, y) for two-dimensional coordinates (x, y),
The method is characterized in that the soldered portion is inspected based on the determined height value Z(x, y).

That is, the present invention focuses on the fact that although the solder surface to be inspected is close to a mirror surface, there are minute irregularities of about 0.01 μm to 0.5 μm on the surface, and uses linearly polarized light (
A polarizing filter is installed on the detection side to block the polarized light in the same direction as the incident light, blocking the specularly reflected light generated from the solder surface, and selectively blocking the scattered light generated from minute irregularities. The reason is that the three-dimensional shape of the solder can be measured by detecting the three-dimensional shape of the solder.

Further, in the present invention, a substrate having a soldered part is placed on a stage, and a minute spot of laser light is irradiated through an objective lens while scanning the soldered part two-dimensionally, and the soldered part is Of the light reflected from the surface of the lens, the image of specularly reflected light formed through the objective lens is blocked by a spatial filter, and the image of the scattered light is received by a photoelectric conversion means and detected as a signal. is relatively moved in the height direction to find the height value Z (x, y) at which the above signal is maximum with respect to the two-dimensional coordinates (x, y), and the value of this found height is The method is characterized in that the soldered portion is inspected based on the value Z (x, y).

In addition, in the present invention, N and A of an optical scanning microscope using a confocal optical system are limited (N, A are 0. 2 or less) The objective lens is used to further scan in two directions to change the condensing position of the light.

[Effect]

By the way, the surface of the solder sample 14 has minute irregularities, and in the scattered reflected light from the solder sample surface, 10 to 20% of the linearly polarized light (S polarized light) has a polarized light component rotated by 90''. (P-polarized light).Since there are minute irregularities on the surface of the solder sample 14, there is light scattered up to a direction of =180° with respect to the incident direction.In the present invention, low N, A By utilizing polarized light using an objective lens of Therefore, when scanning in two directions, the intensity of the light detected from the solder sample can be increased even when the surface of the solder sample is close to a mirror surface, and the peak position of the signal obtained from the sensor can be inspected. The means can be determined correctly, and as a result, the three-dimensional shape of the surface of the solder sample can be calculated correctly.

Moreover, the blocking of specularly reflected light can also be achieved by using a spatial filter instead of using a polarizing element.

When detecting the surface shape of a solder sample, it is necessary to increase the intensity of scattered light generated from minute irregularities on the surface of the solder sample and reduce the specularly reflected light component.

It is desirable that the wavelength of the illumination light is shorter than visible light (700 nm or less), including visible light (700 to 400 nm).

[Embodiment] An embodiment of the soldering visual inspection method and apparatus thereof according to the present invention will be described below with reference to FIGS. 1 and 2. That is, the soldering appearance inspection method and apparatus of the present invention can be roughly divided into stage parts 10. Scanning light generation section 30, optical system section 50, detection section 70. and a detection signal processing section 9o. The stage 10 has a sample 14 having a three-dimensional soldering part.
A sample support stand 11. An X-Y-Z stage 12 on which the sample support table 11 is placed and moves in the x, y, and z directions, and an x-y stage 12 that controls the x-y-z stage 12.
- Consists of a z stage controller 13. x-y
-z stage controller 13 includes detection signal processing section 90
The optical system section 50 detects a preprogrammed inspection point on the sample 14 according to a signal from the microcomputer 91 in the optical system section 50.
automatically transport (position) it to the inspection area. The scanning light generating section 3o is a 1, for example, a He-Ne laser beam 1fi3.
1° beam expander 32, X scanning drive system (x, scanning motion source and its control device 36-
, polarizing beam splitter 34. The Y-scan driving system (Y-scan parking source and its control device!) is composed of 37 and Y-scan mirror 35.Here, for example, the He-Ne laser light source 31 is
In addition, it is desirable to use a laser light source that emits short wavelength laser light, such as an Ar laser light source or a He-Cd laser light source. That is, the laser light source 31 uses visible light (700 to 400 nm).
), it is desirable to emit a laser beam with a wavelength shorter than visible light (700 nm or less). However, when inspecting the three-dimensional shape of a soldered part as in the present invention,
He-Ne laser light (633 nm) is also sufficient. Furthermore, the beam expander 32 is for sending a light beam with a specific spread to the optical system section 50. The spread of this luminous flux is determined by the N, A, (Numerical Aperture) of the incident light, which is the core of the idea of the present invention.
This is what determines the The X-scan drive system 36, the Y-scan drive system 37, the X-scan mirror 33, and the Y-scan mirror 35 are galvano mirrors, but they do not necessarily have to be galvano mirrors, and may be polygon mirrors, holographic scanners, or acoustic mirrors. Other optical scanning means such as an optical element may also be used. Further, in order to enlarge the scanning range and the field of view, a Y scanning mirror 35 that is long in the X direction is used. This can also be made shorter in other scanning directions. Also, as shown in FIG.
This method may have a configuration in which the
High reproducibility of the X-scan drive system 36 is required. On the contrary.

The method shown in FIG. 1 has the advantage that the X-scan drive system 36 is not required to have high reproducibility because the X coordinate is determined by the CCD linear sensor.

The optical system section 50 includes a condenser lens 51 and a field lens 5.
2. It is composed of an objective lens 53, a Z-direction scanning lens 54, and a Z-direction scanning drive system 55 that moves and scans the two-direction scanning lens 54 in the Z direction.

The light scanned in the X and Y directions by the scanning light generator 3o is
The light is focused onto a field lens 52 by a focusing lens 51 . This image is formed near the solder sample 14 by the objective lens 53 and the bidirectional scanning lens 54.

Here, the light beam between the objective lens 53 and the bidirectional scanning lens 54 is designed to be a parallel light beam. Thereby, the distance from the Z-direction scanning lens 54 to the focal point near the sample is always kept constant. That is, by scanning the bidirectional scanning lens 54 in the Z direction, the relative position of the solder sample 14 and the focal point in the Z direction can be scanned (moved).

However, scanning in the Z direction does not necessarily need to use this Z direction scanning lens 54;
The direction scanning lens 54 is fixed as one lens, and scanning (movement) in the Z direction is performed by the x-y-z stage 12.
A Z stage may also be used.

The condensing lens 51 and field lens 52 are used to obtain a necessary observation field of view. However, it is clear that the light may be made to directly enter the objective lens 53 without using the condenser lens 51 and the field lens 52 as long as the field of view is sufficiently large.

The detection unit 70 includes an imaging lens 71 and a -dimensional linear sensor 7.
Consists of 2. Here, the imaging lens 71 includes a Z-direction scanning lens 54, an objective lens 53, and a field lens 5.
2. It is combined with a condensing lens 51, and the condensing position near the sample and the light receiving surface of the detector (-dimensional linear sensor) 72 have a conjugate relationship, that is, an imaging relationship. That is, the above optical system forms a confocal optical system. The -dimensional linear sensor 72 is arranged in a direction that matches the scanning direction of the X scanning mirror 33. By the way, as shown in FIG. 2, when the same scanning mirror 38 is used as the X scanning mirror 35,
- Detects pinhole 73 instead of dimensional linear sensor 72! j! 74 is used.

Furthermore, the polarizing beam splitter 34 separates the light returning from the solder sample 14 from the polarizing beam splitter 34.
This has the effect of suppressing interference with light that is reflected by and enters the one-dimensional linear sensor 72.

The detection signal processing unit 9o includes a microcomputer 91, a detection signal storage means 92. It is composed of a comparator 93, a Z coordinate storage means 74, and the like.

The detection signal storage means 92 stores the values of the signals detected by the one-dimensional linear sensor 72 corresponding to the respective x and y coordinates in accordance with the X and Y scanning of the luminous flux, and outputs them from the comparator 93. This is a frame memory that updates and stores the value. The comparator 93 detects the -dimensional linear sensor 72 for each XeY coordinate every time it scans (moves) in the Z direction.
Each detection signal detected by the detection signal storage means 92 is compared with the value of the signal corresponding to the same X+3' coordinate stored in the detection signal storage means 92, and the larger value is outputted. At the same time as rewriting the value, the Z at that time
The (x, y) coordinates are output to the Z coordinate storage means 94. Thereby, the Z (x, y) coordinate at which the detection signal is maximum is stored in the Z coordinate storage means 94 for each Xt'j coordinate. Therefore, -Xt' is stored in the two coordinate storage means 94.
The stored Z (x, y) coordinates for each / coordinate directly indicate the three-dimensional profile of the solder sample 14.

Therefore, Z(
If the x, y) coordinates are integrated as shown in the following equation, it becomes the volume V, that is, the amount of solder in the soldered part.

V = fJ Z (x, y) dxdy or more The present invention
It takes advantage of the fact that there are minute irregularities on the surface of the soldered part. Therefore, the more microscopic irregularities there are, the more accurate the inspection can be. Therefore, immediately after the soldering process, oxygen gas is sent to oxidize the surface during soldering, thereby increasing the unevenness of the surface due to the oxide film and making it easier to inspect the solder. By oxidizing the solder surface in this way, minute irregularities increase, the solder surface changes from a mirror-like state to a dull state, and scattering light becomes more likely to occur.

Further, as a method of promoting oxidation of the surface of the solder, there is a method of mixing an oxidizing agent into the solder. By mixing an oxidizing agent into the solder in this way, the solder surface can be easily oxidized to form minute irregularities, thereby making it easier to generate scattered light.

Next, the function and operation of the above embodiment will be specifically explained. That is, the solder sample 14 is placed on the stage section 10.

At this time, the microcomputer 91 gives commands to the X-Y-Z stage controller 13 according to a program created and input in advance based on design data, etc.
The y-z stage controller 13 controls the stage 10 to move the solder sample 14 to the programmed X+'/l z
position (position for each solder sample 14), and the microcomputer 91 sends the drive command to the X-scan drive system 36.
and the X-scan drive system 37, the X-scan drive system 36 rotates the X-scan mirror 33, and the X-scan drive system 37 rotates the Y-scan mirror 35. - For example, the He-Ne laser beam oscillated from the He-Ne laser light source 31 is
The beam expander 32 produces a light beam with a specific spread (
Only the laser beam linearly polarized in a specific direction passes through the polarizing beam splitter 34 and is scanned in the X direction by the X scanning mirror 33.
The light is scanned in the direction and enters the optical system section 50.

An incident linearly polarized (for example, S-polarized) laser beam is focused onto a field lens 52 by a condensing lens 51, and this image is focused near the solder sample 14 by an objective lens 53 and a bidirectional scanning (moving) lens 54. is imaged. Here, since the linearly polarized laser light flux (beam) between the objective lens 53 and the Z-direction scanning (moving) lens 54 is formed to be a parallel light flux, the solder is emitted from the two-direction scanning (moving) lens 54. The distance to the focal point on the sample 14 is always kept constant. Specularly reflected light and scattered reflected light are generated from the surface of the solder sample 14. However, the specularly reflected light returns as linearly polarized light (for example, S-polarized light) that has been irradiated and focused.

The scattered reflected light returns having the above-mentioned linearly polarized light component (for example, S-polarized light) and a polarized light component (for example, P-polarized light) perpendicular to the linearly polarized light. Therefore, the image of the light reflected from the surface of the solder sample and returned is formed on the field lens 52, reflected and scanned by the Y scanning mirror 35 through the condensing lens 51, and S-polarized light, which is specularly reflected light, is transmitted by the polarization beam splinter 34. is blocked, and only the P-polarized light included in the scattered reflected light is reflected and enters the detection unit 70, and is imaged on the one-dimensional linear sensor 72 by the imaging lens 71, and then the -dimensional linear sensor 72
An optical image is received by the -dimensional linear sensor 72, and a signal is detected by the -dimensional linear sensor 72.

The reflected light from the solder sample 14 is detected and stored in the detection signal storage means 92.

Further, the two-direction scanning drive system 55 scans the focal point one step in the Z direction, and performs the above-mentioned X and Y scanning. At this time, the detection signal and the already stored detection signal are compared by the comparator 93, and the larger value is selected by the detection signal storage means 9.
At the same time, the value Z(x+y) of 2 at that time is stored in the Z coordinate storage means 94.

Thereafter, this operation is repeated while scanning 2 one step at a time. From the three-dimensional shape created in this way, the amount of solder in a predetermined defect is calculated by integration.

The optical scanning microscope section using the confocal optical system formed in the scanning light generating section 30 and the optical system section 5o has a numerical aperture (N, A,: Numerical Apertu) of the illumination light beam.
re) determines the depth of focus. When the solder sample surface moves away from the focal position in either positive or negative directions, the detection signal becomes weaker. Therefore, if the solder sample 14 and the optical focal position are scanned (moved) relative to each other in the Z direction and the Z coordinate of the position where the detection signal is maximized is detected in the detection signal processing section 90, the position l1z on the surface of the solder is detected. (x, y) 0 When inspecting a solder material part as in the present invention, it is sufficient to have a resolution of about 10 μm in the Xyy direction and several μm in two directions, and depending on the size of the object to be inspected, it is sufficient to have a resolution of several μm to several meters. A line-of-sight field of view is required.

In order to obtain this field of view and resolution, the objective lens 53 is not an objective lens for a microscope, but a lens for film transfer. Specifically, for example, the wavelength λ=633
Depth of focus Δ when using a He-Ne laser of nm and using a lens with N, A, = 0.15 as the 5 objective lens 53
Z can be calculated using the following equation (1).

ΔZ=0.5X(λc,A,)2:8.9(u+)
(1) Next, because the solder surface is close to a mirror surface, there are cases in which specularly reflected light enters the detector and cases in which it does not enter the detector.
A He-N e laser light source 31. to solve the problem of requiring a dynamic range of several orders of magnitude. Polarized illumination consisting of a beam expander 32 and a polarized beam splitter 34, and a two-way scanning lens 54. Objective lens 53. Field lens 52, condensing lens 51, polarizing beam splitter 34. Imaging lens 71. The interaction with the polarization detection system consisting of the and -dimensional linear sensor 72 will be explained. That is, when the illuminated surface is an ideal mirror surface, the reflected light is polarized and reflected in a direction determined by the incident and exit angles and the refractive index of the material.

Let's calculate this polarization angle for the above example. When the angle of incidence is θi, the angle between the plane of incidence and the plane of polarization of the incident beam is αi, and the refractive index of the solder is ns, the angle α between the plane of polarization of the reflected beam and the plane of incidence is α. can be calculated using the following equation (2).

S = sin a i・(-sin (θi−θi'
)/5in(θi+θ1l)p = cos a i+(
tan(θi-θi')/1an(θi+θ1j)n
sinθi' = sinθ1 tanαo ” S / p ・ ・ ・ ・ (2) Therefore, if the objective lens 53 has N, A, = 0.15, the maximum value of θj at which the specularly reflected light returns into the lens is 8.6. °
It is. At this time, the refractive index of the solder is assumed to be 4.0. −αi is maximum when αj=45°, and α. −
αi=0.32''. This angle change is expressed by the following formula (
The polarized light is disturbed by the component shown in 3).

5in (α.-αi) #0.0055 ・ ・ ・ ・
(3) That is, the component that disrupts polarization is only 0.5%. Focusing on this fact, if the polarizing filter 34 is installed on the detection optical system side, up to 99.5% of the specularly reflected light can be blocked. Here, in equation (2), when θi is, for example, 60'.

α. −α1=20@sin (α0−α1)=0.34, and considering that even if a polarizing filter is included, only 66% of the specularly reflected light can be blocked, the present invention can also reduce N and A of the illumination optical system. Special conditions taken into consideration (from the above relationship, the field of view is expanded as the objective lens 53, and the N of the objective lens 53 is
, A, was set to about 0.2 or less. ), it can be seen that it holds true when. In other words, the surface of solder sample 14 has minute irregularities, and experiments have shown that in the scattered reflected light from the solder sample surface, 10 to 20% of linearly polarized light (S-polarized light) has a direction rotated by 90''. The polarization component of (
P-polarized light). Since there are minute irregularities on the surface of the solder sample 14,
There is light that is scattered in the direction of . (E, 1lolf et al.: Pr1nciples of 0ptics pp9
50-962) As in the above embodiment, when polarized light is used, the dynamic range between when the specularly reflected light reflected from the surface of the solder sample 14 enters the detection section 70 and when it does not enter the detection section 70 can be increased by 3 to 4 orders of magnitude. can be reduced. Therefore, the intensity of the light detected from the surface of the solder sample 14 when scanning in two directions can be increased, and the comparing means 93 can correctly determine the peak position of the signal obtained from the sensor 72, and as a result, the memory 94 can correctly calculate the three-dimensional shape of the surface of the solder sample 14.

When detecting the surface shape of the solder sample 14, it is necessary to shorten the wavelength of the illumination light (visible It is preferable to increase the intensity of the scattered light by making the wavelength shorter than that of the light (<700 nm or less), which is expressed by the above formula (2).
and (EJolf et al.: Pr1ciples of 0
ptics pp950-962).

Next, an example of an algorithm for inspecting solder based on the three-dimensional shape of the solder sample 14 detected as described above will be explained with reference to FIGS. 5 to 7.

FIG. 5 is a perspective view of the solder sample 14. Normal part 121
, a small amount of solder portion 122, a large amount of solder portion 123, and a defective solder portion 124 are present. FIG. 6 is a side view of FIG. 5. Windows 125, 126, 127, and 128 and cutting lines 129, 130, 131, and 132 are shown overlapping each other. FIG. 7(a) is a sectional view of the normal part 121, and FIG. 7(b)
) is a cross-sectional view of the small amount of solder portion 122, (c) is a cross-sectional view of the large amount of solder portion 123, and (d) is a cross-sectional view of the solder defective portion 12.
4 is a sectional view of FIG. In addition, FIG. 8 shows the cut line 129.
These are the detection results of 130.131.132 parts according to the present invention. FIG. 9 shows the differential values of FIG. This is the threshold 133
It is possible to judge whether it is good or bad.

Consider the case where the solder sample 14 shown in FIG. 5 is to be inspected. The positions of the soldered parts to be inspected are programmed in advance in the microcomputer 91 from design data of the printed circuit board.

3 generated on the memory 94 according to this program.
Windows 125 to 128 are provided at predetermined positions in the dimensional shape, and the volume within the window is calculated by integrating zmz(x, y).

If this value is within a predetermined range, the product is considered non-defective. Furthermore, the shapes of the cutting lines 129 to 132 within the window are determined, and the differential values thereof are shown in FIGS. 8(b) and 8(c).

If it changes discontinuously like (d), it is considered defective.
As shown in FIG. 5(a), a case where the change is smooth is considered to be a good product.

FIG. 3 shows a third embodiment of the present invention. In the first embodiment, specularly reflected light is blocked by a polarizing plate, whereas in the third embodiment, specularly reflected light is actively taken in. That is, as shown in FIG.
The beam is set to coincide with the focal point 57 of the objective lens 58 on the surface of the solder sample 14, and the light beam emitted in a direction that does not enter the objective lens 58 is reflected toward the focal point 57 by the spherical mirror 56. The structure is such that it returns to the field of view of the objective lens 58. With this configuration, the dynamic range with respect to the surface orientation of the solder sample 14 is relaxed. That is,
Almost all of the diffusely reflected light enters the field of view of the objective lens 58 without being affected by the orientation of the surface of the solder sample 14, allowing the three-dimensional shape of the solder sample surface to be detected with high sensitivity. Here, the condensing point 57 is fixed to the sample support stand 11, which is a wiring board having the solder sample 14, in the X and Y directions.
- It is necessary to drive and control the Z stage 12 to scan (move) it. Therefore, the X scan drive rfX36, the Y scan drive system 37. The Z scanning drive system 55 can be omitted. Further, the objective lens 53 and the Z direction scanning lens 54 can be combined into an objective lens 58. This method uses solder sample 1
The sample support stand 11 on which the wiring board with 4 is placed is
This x-
The Y.2 stage 12 is required to be large and highly accurate.

FIG. 4 shows a fourth embodiment of the present invention. That is, in the fourth embodiment, specularly reflected light is blocked by a spatial filter 59 instead of the polarizing element (polarized beam splinter 34) shown in the first and second embodiments. This allows the sensor (
It is detected by a detector) 74 and has the same effect as the device shown in FIGS. 1 and 2. That is, for example, He-
The beam diameter of the laser beam emitted from the Ne laser light source 31 is expanded by a beam expander 32, and a mirror (also serving as a spatial filter) is installed between the objective lens 53 and the Z-direction scanning lens 54.

) 59 and is focused on the surface of the solder sample 14 via the Z-direction scanning lens 54 which is scan-driven by the Z-scanning drive system 55. Here, a He-Ne laser 31, a beam expander 32. Mirror 59, objective lens 53. and Z direction scanning lens 54 two-dimensionally (x, direction, and
It is clear that the x-y-z stage 12 may be scanned in the X direction and the Y direction if the stage 12 is fixed in the X direction and the Y direction.

Further, the detection system 70 uses a pinhole 73 and a sensor 74, similar to the embodiment shown in FIG. It is clear that this sensor 74 need not also be a one-dimensional linear sensor.

〔Effect of the invention〕

According to the present invention, when inspecting the appearance of soldered parts on a board, a microscope having a confocal optical system using a low N, A objective lens is used to block specularly reflected light with a polarizing element or a spatial filter. Since the three-dimensional shape of the solder sample surface, which is close to a mirror surface, is measured, the amount of solder can be calculated, and the soldered portion can be inspected with high reliability and at high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the soldering part visual inspection apparatus of the present invention, FIG. 2 is a block diagram showing a second embodiment of the soldering part visual inspection apparatus of the present invention, FIG. 3 is a configuration diagram showing a third embodiment of the soldering part visual inspection apparatus of the present invention, and FIG. 4 is a configuration diagram showing the third embodiment of the soldering part visual inspection apparatus of the present invention. 5 is a perspective view showing a solder sample according to the present invention, FIG. 6 is a plan view of FIG. 5, and FIG.
The figure is a side view showing the solder sample according to the present invention, Figure 8 is a diagram showing the shape signal waveform calculated by the present invention for the solder sample shown in Figure 7, and Figure 9 is the shape signal waveform shown in Figure 8. It is a figure which shows the differential signal waveform obtained by differentiating. 10... Stage section 11... Sample support stand 12
-X -Y -Z stage l 3-X -Y -ZX
Chip controller 14...Solder sample 30...Scanning light generator 31
...Laser light source 32...Beam expander 3
3...X scanning mirror 34...Polarizing beam splitter 35...Y scanning mirror 50...Optical system section 51.
Condensing lens 52...Field lens 53...
・Objective lens 54...2-direction scanning lens 7o・
・Detection unit 71...imaging lens 72...-
Dimensional linear sensor 90...Detection signal processing unit 91...Microcomputer Kyo 2 R force number G number (b) Otsu (C) (d)

Claims (18)

[Claims] 1. A board having a soldered part was placed on a stage, and a minute spot of linearly polarized light was irradiated through an objective lens while scanning the soldered part two-dimensionally, and reflected from the surface of the soldered part. Among the light, the image of specularly reflected light that is formed through the objective lens is blocked by a polarizing element, and the image of the scattered light is received by a photoelectric conversion means and detected as a signal. The height value Z (x, y) at which the above signal becomes maximum when moving in the direction is determined for the two-dimensional coordinates (x, y), and this determined height value Z (x, y ) A method for inspecting the appearance of a soldered part, characterized by inspecting the soldered part. 2. N. of the above objective lens. A. 2. The method for visually inspecting a soldered part according to claim 1, wherein: 0.2 or less. 3. Claim 1 further characterized in that a spherical reflecting mirror reflects light that has expanded beyond the field of view of the objective lens, out of the light reflected from the surface of the soldering part, to the irradiation condensing point.
Appearance inspection method for soldered parts described. 4. 2. The method for visually inspecting a soldered part according to claim 1, wherein the irradiation light is a laser beam having a wavelength shorter than that of visible light. 5. A board with a soldered part is placed on a stage, and a minute spot of laser light is irradiated through an objective lens while scanning the soldered part two-dimensionally, and the light reflected from the surface of the soldered part is detected. The specularly reflected light image formed through the objective lens is blocked by a spatial filter, and the scattered light image is received by a photoelectric conversion means and detected as a signal. The height value Z (x, y) at which the above signal is maximum when moving in the direction
is determined for two-dimensional coordinates (x, y), and the soldered portion is inspected from the determined height value Z(x, y). . 6. N. of the above objective lens. A. 6. The method for visually inspecting a soldered part according to claim 5, wherein: 0.2 or less. 7. Claim 5, further comprising a spherical reflecting mirror that reflects light that has expanded beyond the field of view of the objective lens, out of the light reflected from the surface of the soldering part, to the irradiation condensing point.
Appearance inspection method for soldered parts described. 8. 6. The method for visually inspecting a soldered part according to claim 5, wherein the irradiation light is a laser beam having a wavelength shorter than that of visible light. 9. a stage on which a board having a soldering part is placed and positioned; an irradiation means for irradiating the soldering part with a minute spot of linearly polarized light while scanning the soldering part two-dimensionally through an objective lens; a detection means for blocking a specularly reflected light image formed through an objective lens out of the light reflected from the surface of the object with a polarizing element and receiving a scattered light image by a photoelectric conversion means and detecting it as a signal; a moving means for relatively moving the light spot in the height direction, and a height value Z( x, y) with respect to the two-dimensional coordinates (x, y), and the height value Z(x, y) found by the height detection means for the soldering part. 1. An appearance inspection device for a soldered part, comprising an inspection means for inspection. 10. N of the objective lens of the irradiation means and detection means. A
．． 10. The apparatus for inspecting the appearance of a soldered part according to claim 9, wherein the soldering part is formed with a value of 0.2 or less. 11. Furthermore, among the light reflected from the surface of the soldering part,
10. The soldering part visual inspection apparatus according to claim 9, further comprising a spherical reflecting mirror that reflects light spread out from the field of view of the objective lens to the irradiation condensing point. 12. 10. The soldering part visual inspection apparatus according to claim 9, wherein the irradiation means is a laser beam having a wavelength shorter than that of visible light. 13. 10. The soldering part external appearance inspection apparatus according to claim 9, wherein the inspection means is configured to set a window based on design data and inspect the inside of the window. 14. a stage on which a board having a soldered part is placed and positioned; an irradiation means for irradiating the soldered part with a minute spot laser beam through an objective lens while scanning the soldered part two-dimensionally; and a surface of the soldered part. A detection means for blocking a specularly reflected light image through an objective lens with a spatial filter and detecting the scattered light image by a photoelectric conversion means and detecting it as a signal; a moving means for moving in the horizontal direction; and a height value Z (x, y) at which the signal detected by the detecting means is maximum when the moving means relatively moves the minute spot laser beam in the height direction. is the two-dimensional coordinate (x, y)
A soldering device characterized by comprising: a height detecting means for determining the height of the soldering portion; and an inspecting means for inspecting the soldered portion from the height value Z(x, y) determined by the height detecting means. department's visual inspection equipment. 15. N of the objective lens of the irradiation means and detection means. A
．． 15. The soldering part visual inspection apparatus according to claim 14, wherein the soldering part appearance inspection apparatus is formed with a value of 0.2 or less. 16. Furthermore, among the light reflected from the surface of the soldering part,
15. The soldering part visual inspection apparatus according to claim 14, further comprising a spherical reflecting mirror that reflects light spread out from the field of view of the objective lens to the irradiation condensing point. 17. 15. The soldering part visual inspection apparatus according to claim 14, wherein the irradiation means is a laser beam whose wavelength is shorter than that of visible light. 18. 15. The soldering part visual inspection apparatus according to claim 14, wherein the inspection means is configured to set a window based on design data and inspect the inside of the window.