JP2007198825A - Visual examination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect an inspection target by a simple and compact constitution in a visual examination device. <P>SOLUTION: The visual examination device 50 of a substrate 3 is equipped with a scanning mechanism for relatively moving the substrate 3, an illumination part 11 and an imaging part 12 and further equipped with the deflecting element 10, which is arranged on the optical path between the region of the illumination part 11 and the imaging part 12 and the substrate 3 to deflect the light from the linear inspection position M of the substrate 3 in a predetermined deflecting direction, and moving mechanisms 30 and 31 for relatively moving the illumination part 11 and the imaging part 12, in a direction orthogonal to the optical path and the line direction of the inspection position M. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an appearance inspection apparatus. For example, the present invention relates to an appearance inspection apparatus that performs an appearance inspection such as the presence or absence of scratches, defects, pattern abnormalities, dust adhesion, etc. on a semiconductor wafer substrate or a liquid crystal substrate.

Conventionally, illumination light from a predetermined direction is applied to a subject in order to inspect the subject, such as a semiconductor wafer substrate or a liquid crystal substrate, on which a periodic pattern is formed, such as scratches, defects, pattern abnormalities, and dust adhesion. Is used to image the diffracted light, specularly reflected light, scattered light, and the like from the subject, and image processing is performed on the captured image data to determine the presence or absence of defects.
For example, Patent Document 1 describes a substrate inspection apparatus that irradiates a subject with illumination light from a surface light source, captures a diffraction image of the subject with a camera, and detects a defect with an image processing unit. The emission direction of the diffracted light varies depending on the pattern pitch of the subject. Therefore, here, conditions are set for the apparatus so that a diffracted image can be captured by moving the camera or rotating the subject on a tilt stage in accordance with the direction of emission of the diffracted light.
Patent Document 2 discloses a line illumination unit that irradiates a subject with line-shaped illumination light, a one-dimensional imaging unit that images light from the subject, and the subject orthogonal to the line-shaped illumination region. A transfer unit that moves in a direction, and an image processing unit that reconstructs a two-dimensional image from image information captured by the one-dimensional imaging unit and performs defect determination. The line illumination unit and the one-dimensional imaging unit There is described a surface defect inspection apparatus in which specular reflection light and diffracted light from a subject can be imaged by a single one-dimensional imaging unit by varying an inclination angle.
Japanese Patent No. 3669101 (FIGS. 1 and 5) Japanese Patent No. 3668294 (FIGS. 1 and 2)

However, the conventional visual inspection apparatus as described above has the following problems.
In the technique described in Patent Document 1, although the subject image can be acquired collectively by irradiating the subject with a surface light source, the light source becomes larger and the apparatus becomes large as the subject size increases. There's a problem. In recent years, as semiconductor wafer substrates and liquid crystal substrates have been increased in size, it has been strongly required to make the appearance inspection apparatus compact. However, there is a problem that this technique cannot be made compact.
In the technique described in Patent Document 2, since the imaging range is a line and the subject is scanned to acquire a two-dimensional image, the apparatus can be downsized compared to the apparatus described in Patent Document 1, but the illumination light In order to change the incident angle and the imaging direction, it is necessary to rotate and move the line illumination unit and the one-dimensional imaging unit around the linear imaging range.
In this case, for example, if the diameter of the semiconductor wafer substrate is 300 mm, the linear imaging range of this length must be reduced and projected onto a one-dimensional image sensor of about 30 mm, for example, so that the optical path length is about 500 mm to 700 mm. Also become.
Therefore, in the case of rotational movement, it is necessary to provide at least this rotation radius, and the rotation mechanism becomes large, and an arrangement space corresponding to the rotation radius is required as a dead space, and the occupied space at the time of use is increased. There is a problem that it gets bigger.
In addition, when the rotation radius of the line illumination unit and the one-dimensional imaging unit is increased, there is a problem that the rotational driving load is increased, the moving time is increased, and the inspection efficiency is lowered.
Instead of the rotational movement mechanism, it is conceivable to tilt the subject as disclosed in Patent Document 1, but the tilt mechanism must be increased in accordance with the size of the subject, and the mechanism itself is expensive. There is a problem of end.

  The present invention has been made in view of the above problems, and an object thereof is to provide an appearance inspection apparatus that can inspect a subject with a simple and compact configuration.

In order to solve the above-described problems, in the present invention, an illuminating unit that generates illumination light that irradiates a subject or an imaging unit that forms an image by imaging light from a line-shaped inspection position of the subject on a line imaging device. A visual inspection apparatus for performing visual inspection of the subject by relatively moving at least one of the optical units and the subject to change the examination position, A deflecting element that is arranged on an optical path between an optical unit and the subject and deflects light from the line-shaped inspection position of the subject or light to the line-shaped inspection position of the subject in a predetermined direction And at least one of the optical units includes a moving mechanism that relatively moves in a direction orthogonal to the optical path direction inside the optical unit and the longitudinal direction of the linear inspection position.
According to the present invention, the deflection element that deflects light from the line-shaped inspection position of the subject in a predetermined direction is disposed on the optical path between the optical unit and the subject. It is possible to align the emission direction of the illumination light and / or the direction in which the light from the subject enters the imaging unit so as to be parallel to each other inside the optical unit, and further, at least one of the optical units is moved by the moving mechanism. Is relatively moved in a direction orthogonal to the longitudinal direction of the optical path and the line-shaped inspection position in the optical unit, so that the incident direction of the illumination light to the subject or It is possible to easily set the conditions of the apparatus in accordance with the light emission direction from the subject.
In addition, when there are a plurality of optical units arranged on the optical path passing through the deflecting element, the optical units are the same with the arrangement directions of the plurality of optical units aligned so that the optical paths in the optical units are parallel to each other. By moving along the direction, the incident direction of the illumination light and the direction of the light from the subject guided to the imaging unit can be varied.
Therefore, a simple configuration can be achieved without using a large rotating mechanism.

Note that the deflection direction of the deflection element can be any appropriate direction, but is preferably normal to the plane of the substrate that is the subject.
Further, as the deflecting element is brought closer to the subject, the light that spreads from the examination position within a certain angle range is deflected within a narrower width, and the amount of movement by the moving mechanism can be reduced.
Further, since the optical path between the deflecting element and the optical unit is formed in a predetermined direction by the deflecting element, for example, a deflecting means such as a plane mirror is arranged to deflect the light in a direction different from the deflecting direction and bend the optical path. be able to. Thereby, for example, it becomes easy to change the arrangement position and the moving direction of the optical unit according to the necessity of the apparatus layout.

In this specification, the optical unit is used as a term indicating an illuminating unit that generates illumination light to irradiate a subject or an imaging unit that performs imaging by imaging light from a subject on a line imaging element, Includes at least a light source or a line imaging device.
Therefore, the optical unit in this specification may actually be unitized as an apparatus configuration, but may not be unitized. Even in the case of unitization, the actual number of mechanical unit configurations does not necessarily correspond.

In the appearance inspection apparatus of the present invention, it is preferable that the deflection element is composed of a lens or a lens group having power only in one axial direction.
In this case, the light radiated from the inspection position can be converged in a uniaxial direction to be a parallel light, so that all the light radiated from the inspection position to the NA range of the lens or lens group is in a certain direction. Can be deflected.

In the appearance inspection apparatus of the present invention, it is preferable that the deflection element is formed of a concave mirror having power only in one axial direction.
In this case, since a concave mirror which is a reflection optical system is used, an image having no chromatic aberration can be taken.

In the appearance inspection apparatus of the present invention, the at least one optical unit is composed of two optical units including the illumination unit and the imaging unit, and the two optical units are independently moved. It is preferable that the structure be held by a possible moving mechanism.
In this case, the light from the optical unit comprising the illumination unit is deflected by the deflecting element and irradiated to the inspection position, and the light incident on the deflecting element among the light reflected, diffracted or scattered at the inspection position is deflected in the deflection direction. The optical unit can be deflected and imaged by an imaging unit. Then, the two optical units are appropriately moved independently along the same direction by the moving mechanism. As a result, the incident direction of the illumination light can be varied, or light from the subject traveling in different directions can be imaged. For this reason, by independently moving the positions of the two optical units, various specularly reflected light, diffracted light, and scattered light can be measured under optimum apparatus conditions.

In the appearance inspection apparatus of the present invention, the at least one optical unit is composed of two optical units, the illumination unit and the imaging unit, the two optical units and the deflection element. It is preferable that an optical path synthesizing unit that guides light traveling from the subject along the same optical path to which the illumination light from the illumination unit is directed to the subject is provided to the imaging unit.
In this case, the light path synthesizing unit can guide the light traveling from the subject along the same optical path as the illumination light from the optical unit including the illumination unit to the imaging unit, so that the incident and exit directions with respect to the subject are the same. An image of diffracted light that satisfies the Bragg condition can be taken.

Moreover, in the appearance inspection apparatus provided with the optical path synthesizing unit of the present invention, the incident direction of the illumination light by the illuminating unit or the imaging unit on any optical path between the two optical units and the subject It is preferable that the apparatus includes an optical path switching unit that switches an imaging direction of light from the subject to be imaged.
In this case, the optical path switching means uses the optical path synthesizing means to capture a diffraction image when the Bragg condition is satisfied, and captures a diffraction image other than the Bragg condition, a regular reflection image, or an image by scattered light. The inspection to be performed can be switched.

In the appearance inspection apparatus of the present invention, the at least one optical unit includes two optical units including the illumination unit and the imaging unit, and the deflection element includes the two optical units. It is preferable that the unit includes two deflection elements having different configurations depending on each unit.
In this case, since the deflection element is composed of two deflection elements having different configurations depending on the optical unit consisting of the illumination unit and the optical unit consisting of the imaging unit, each deflection element can be optimized according to each optical unit. it can.
For example, by setting each deflection direction deflected by each deflection element to a different direction, the arrangement position and movement direction of each optical unit can be changed, and the degree of freedom of device layout can be increased.
In addition, for example, illumination light that only needs to be able to illuminate the inspection position in a line shape is a deflection element that does not have power, such as a plane mirror, and only the deflection element on the optical unit side that is an imaging unit has power. Simplification of the deflection element can be achieved.

In the appearance inspection apparatus of the present invention, the at least one optical unit includes a plurality of optical units each including the imaging unit, and the illumination unit illuminates the subject without passing through the deflection element. A structure in which light is irradiated is preferable.
In this case, since the illumination light does not pass through the deflection element, it is possible to omit the arrangement space of the optical element formed of the illumination unit and to simplify the configuration of the deflection element.

  According to the appearance inspection apparatus of the present invention, the deflection element can be arranged on the optical path between the subject and the optical unit, and the optical unit can be arranged along the direction of the light passing through the deflection element. By moving the unit in one axis direction, it becomes possible to change the direction of illuminating the subject with the illumination light, or to always image the light from the subject having different emission directions depending on the subject. Compared to the case where the subject is rotated or the subject is tilted, an examination suitable for the subject can be performed with a simple and compact configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An appearance inspection apparatus according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic configuration diagram of an appearance inspection apparatus according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a deflection element that can be used in the appearance inspection apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram showing another example of the deflection element that can be used in the appearance inspection apparatus according to the first embodiment of the present invention.
The XYZ Cartesian coordinate system described in each figure (the same applies hereinafter) is drawn in common for each figure for convenience of reference of the direction, and the arrangement plane of the subject is the XY plane, and its normal is This is a coordinate system in the Z-axis direction.

A substrate appearance inspection apparatus 50 (appearance inspection apparatus) according to the present embodiment shown in FIG. 1 acquires, for example, scratches, by acquiring a two-dimensional image of the substrate 3 that is a flat specimen on which a periodic pattern is formed. This is to inspect for the presence of defects, pattern abnormalities, dust adhesion, and the like. As the substrate 3, for example, a semiconductor wafer substrate or a liquid crystal substrate can be employed.
The schematic configuration of the substrate appearance inspection apparatus 50 includes an illumination unit 11 (optical unit), a moving mechanism 30, a deflection element 10, an imaging unit 12 (optical unit), a moving mechanism 31, and a control unit 32.
A plane C in the drawing represents a plane perpendicular to the substrate 3 (a plane parallel to the YZ plane in the drawing) passing through the line-shaped inspection position M that is the longitudinal direction in the Y-axis direction in the drawing on the substrate 3 (hereinafter, each drawing). The same).
The substrate visual inspection apparatus 50 includes a substrate moving stage that supports the substrate 3 on the XY plane in the drawing and is relatively movable in the X-axis direction in the drawing, although not particularly shown. Then, the inspection position M is illuminated, and the substrate moving stage is driven so that the substrate 3 is relatively moved and can be scanned in the X-axis direction in the drawing.

  The illumination unit 11 is an optical unit in which, for example, a light source 1 that emits divergent light such as white light and a collimator lens 2 that converts the divergent light emitted from the light source 1 into parallel light are integrally held in a housing. The shaft is disposed above the deflection element 10 in a state along the Z-axis direction in the figure. The moving mechanism 30 is supported so as to be movable in the X-axis direction in the figure.

The collimating lens 2 is an optical element for making the divergent light emitted from the light source 1 into a parallel light beam, and is constituted by, for example, a cylindrical lens having power only in the longitudinal direction (YZ plane in the drawing) of the inspection position M.
With such a configuration, the illumination unit 11 can emit a line-shaped substantially parallel light beam having a longitudinal direction along the Y axis to the inspection position M.
The parallel light flux has a band shape because it has a width in the X-axis direction in the figure, but the width is a relative size, and in this specification, it is somewhat to the extent that it is not necessary to distinguish between them. Even if it has a width of 2 mm, it is referred to as a line shape if it can be regarded as being one-dimensional.

The moving direction of the moving mechanism 30 is set to the X-axis direction shown in the drawing, which coincides with the scanning direction of the substrate 3. As the configuration of the moving mechanism 30, an appropriate uniaxial moving stage mechanism such as a linear stage having a ball screw or a linear motor driving mechanism can be adopted.
The movement mechanism 30 is connected to the control unit 32, and the movement amount is controlled by the control unit 32 by a control signal.

  The deflecting element 10 is disposed between the illumination unit 11 and the imaging unit 12 and the substrate 3, and the illumination light emitted from the illumination unit 11 and traveling in the negative Z-axis direction is illustrated in the longitudinal direction of the linear inspection position M. Is an optical element for deflecting in the direction of the inspection position M within the ZX plane shown in the drawing. Therefore, conversely, when light emitted from the inspection position M into the illustrated ZX plane enters the deflecting element 10, it is deflected in the illustrated Z-axis positive direction. That is, the optical axis is deflected in a direction approaching the normal on the inspection position M of the substrate 3 that is the subject.

As such a deflection element 10, for example, a cylindrical lens 111 as shown in FIG. 2 can be adopted.
The cylindrical lens 111 is a lens having power only in the illustrated ZX plane, and is arranged such that its focal position coincides with the inspection position M of the substrate 3. That is, the cylindrical lens 111 is a lens that collects light incident on the substrate 3 from above the Z axis on the inspection position M.

  In FIG. 2, the cylindrical lens 111 is illustrated as a single lens, but may be configured by a lens group in which a plurality of lenses are arranged in the Z-axis direction.

As another example of the deflecting element 10 having the same deflecting action, for example, a concave mirror 112 as shown in FIG. 3 may be adopted.
The concave mirror 112 is an optical element that includes a reflecting surface that reflects and deflects light incident parallel to the surface C and has a uniaxial power for converging at the inspection position M in the ZX plane shown in the drawing. Although FIG. 3 shows an example using a surface reflecting mirror, a concave mirror having an internal reflecting surface may be used.
FIG. 3 shows an example in which the incident / exit light to the concave mirror 112 is provided on the same direction side with respect to the surface C, that is, an example using diffracted light or scattered light. If arranged at the position, the incident light and the outgoing light can be deflected on both sides of the surface C, respectively, and can be used for inspection of a regular reflection image.

The imaging unit 12 captures an image of the substrate 3 at the inspection position M with light emitted from the deflecting element 10, and the collimating lens 4, the imaging lens 5, and the line sensor 6 (line imaging element) are provided in the casing. The optical unit is integrally held, and is disposed above the deflecting element 10 in a state where the optical axis is along the Z-axis direction in the drawing. The moving mechanism 31 is supported so as to be movable in the X-axis direction in the figure.
The configuration of the moving mechanism 31 can be the same as that of the moving mechanism 30. The movement mechanism 31 is connected to the control unit 32, and the movement amount is controlled by the control unit 32 by a control signal. The moving amount and moving direction of the moving mechanism 31 can be set independently of the moving mechanism 30 as long as the illumination unit 11 and the imaging unit 12 do not interfere with each other.

The collimating lens 4 is an optical element for condensing the substantially parallel light beam emitted from the deflecting element 10 onto the imaging lens 5. In the present embodiment, the same configuration as that of the collimating lens 2 can be employed.
The imaging lens 5 is an optical element for imaging the light from the collimating lens 4 on the imaging surface of the line sensor 6.
The line sensor 6 is a one-dimensional image sensor for photoelectrically converting an image formed by the imaging lens 5, and for example, a one-dimensional CCD sensor can be used.
That is, in the present embodiment, the deflecting element 10, the collimating lens 4, and the imaging lens 5 constitute an imaging optical system in which a line image on the inspection position M is projected onto the line sensor 6 in a reduced manner.
The image signal photoelectrically converted by the line sensor 6 is output to the control unit 32.

  The control unit 32 includes a substrate visual inspection apparatus including movement control of the movement mechanisms 30 and 31, image processing of an image signal output from the line sensor 6, movement control of a substrate movement stage mechanism (not shown) that relatively moves the substrate 3. For example, it can be configured by appropriate hardware that performs each control or a computer including a CPU, a memory, an input / output device, and the like.

Next, the operation of the substrate appearance inspection apparatus 50 will be described focusing on the action of the deflection element 10.
The light emitted from the light source 1 is converted into a line-shaped parallel light flux extending in the longitudinal direction about the Y axis by the collimator lens 2 and enters the deflection element 10 as illumination light 70 as shown in FIG.

Illuminating light 70, for example, when entering from the position of x ₁ in the X-axis negative direction from the surface C to the deflection element 10, by the action of the cylindrical lens 111 is deflected toward the testing position M while being converged. For this reason, the illumination light 70 is irradiated to the inspection position M on the substrate 3 at an incident angle that forms an angle θ _i with respect to the surface C, as shown in FIG. That is, the inspection position M is illuminated with a linear illumination light condensed in the X-axis direction.
A part of this illumination light is reflected at the inspection position M as the specularly reflected light in the direction of the emission angle θ _i , and a part is diffracted in a direction according to the pattern pitch of the periodic pattern formed on the substrate 3. Further, some of the light is scattered in various directions by dust or scratches on the inspection position M. Therefore, the light from the substrate 3 becomes a plurality of lights traveling in various directions with the inspection position M as the center.
For example, as shown in FIG. 2, reference to the diffracted light exists in the direction of the exit angle theta _d when incident on the substrate 3 at an angle theta _i, at a distance x ₂ from the surface C to the X-axis positive direction, the detection The light 71 is emitted from the cylindrical lens 111. Thus, the imaging unit 12 is arranged to move at a distance x ₂ from the plane C, thereby detecting light 71 from the substrate 3 is incident on the imaging unit 12.

The detection light 71 incident on the imaging unit 12 is collected by the collimating lens 4, reduced and projected by the imaging lens 5, and imaged on the imaging surface of the line sensor 6.
For this reason, the line sensor 6 acquires image information of light that is incident on the inspection position M at the incident angle θ _i and travels in the direction of the emission angle θ _d and is sent to the control unit 32 as an image signal.
In this way, the image information on the substrate 3 is acquired for one line.

  Next, a substrate moving stage mechanism (not shown) is driven by the control unit 32, and the substrate 3 is moved in the X-axis direction by one pixel of the line sensor 6, for example. And the image information of an adjacent line is acquired by repeating said process. By repeating this, the substrate 3 is scanned in the X-axis direction in the figure, and two-dimensional image data of the substrate 3 is acquired.

The angles θ _i and θ _d are set to appropriate angles by driving the moving mechanisms 30 and 31, respectively, and appropriately setting the arrangement positions x ₁ and x ₂ of the illumination unit 11 and the imaging unit 12.
For example, in the inspection of specularly reflected light, x ₁ = x ₂ and θ _i = θ _d is set.
In the inspection of diffracted light, the distance between x ₁ and x ₂ is changed to set the direction in which diffracted light exists. The direction in which the diffracted light exists is determined from the relationship of the following equation where the pattern pitch of the substrate 3 is P.
m · λ = P · (sin θ _d −sin θ _i ) (1)
Here, m is an integer indicating the diffraction order, and λ is the wavelength of the illumination light 70.
Further, in the measurement of scattered light, the angle is set appropriately so that a dark field image can be obtained.

Next, if necessary, the angles θ _i and θ _d are changed, and the above inspection is repeated.
In this case, each angle is changed by moving the positions of the illumination unit 11 and the imaging unit 12 linearly in the X-axis direction shown in the drawing by the moving mechanisms 30 and 31. Therefore, compared with the case where the optical unit is rotated around the inspection position M, the movement range on the deflection element 10 can be suppressed to a much narrower range.
Moreover, since the angular position can be moved quickly, the inspection efficiency can be improved.
Further, the uniaxial moving mechanism has an advantage that a simple mechanism can be adopted as compared with the rotational moving mechanism.

[Second Embodiment]
An appearance inspection apparatus according to a second embodiment of the present invention will be described.
FIG. 4 is a schematic configuration diagram of an appearance inspection apparatus according to the second embodiment of the present invention.
The board appearance inspection apparatus 51 (appearance inspection apparatus) of the present embodiment replaces the illumination section 11 and the imaging section 12 which are two optical units of the board appearance inspection apparatus 50 of the first embodiment, and the first imaging section 22. (Optical unit), a second imaging unit 23 (optical unit), a control unit 33 instead of the control unit 32, and a line light source 101 (illumination unit) and a collimating lens 401 are added. Hereinafter, a description will be given focusing on differences from the first embodiment.

The line-shaped light source 101 is an illuminating unit for illuminating the inspection position M in a line shape, and irradiates the inspection position M with linear illumination light from a predetermined angle direction without passing through the deflection element 10. is there. For example, various light sources such as a configuration including light emitting elements arranged in a line or a configuration having a line-shaped light emitter can be employed. Further, if necessary, a reflecting plate, a condensing lens, an aperture stop, or the like for adjusting the linear range or adjusting the divergence angle may be provided, or the irradiation angle to the substrate 3 can be changed. A mechanism may be provided.
When a reflector or a condenser lens is not provided, a light source with a simple configuration can be obtained. In this case, in order to improve illumination efficiency, the line light source 101 is preferably arranged close to the inspection position M.

The first imaging unit 22 is obtained by deleting the collimating lens 4 from the imaging unit 12 of the first embodiment.
The second imaging unit 23 includes a line sensor 15 (line imaging element) having the same configuration as the line sensor 6 and the imaging lens 5, and an imaging lens 14 integrally held in a housing. Similarly to 22, the light incident along the direction parallel to the surface C is condensed by the imaging lens 14 and can be imaged on the line sensor 15. The line-shaped image information acquired by the line sensor 15 is sent to the control unit 33 as an image signal.
The second imaging unit 23 is supported by the moving mechanism 31 so as to be movable in the X-axis direction in the drawing.
That is, the first imaging unit 22 and the second imaging unit 23 can set their movement amount and movement direction independently within a range in which the movement mechanisms 30 and 31 do not interfere with each other.

The collimating lens 401 is disposed on the optical path between the first imaging unit 22 and the second imaging unit 23 and the deflecting element 10 and condenses a substantially parallel light beam emitted from the deflecting element 10 to the upper side in the drawing. That is, as a configuration similar to the collimating lenses 2 and 4 of the first embodiment, the lens thickness (dimension in the X-axis direction in the drawing) is sufficiently included in the movable range of the first imaging unit 22 and the second imaging unit 23. The set one is adopted.
That is, the deflection element 10, the collimating lens 401, and the imaging lens 5 (14) of the present embodiment are the same as the deflection element 10, the collimating lens 4 (2), and the imaging lens 5 (1) of the first embodiment. A simple imaging optical system.

  The control unit 33 has substantially the same configuration as that of the control unit 32, and copes with a difference in configuration such that the moving mechanism 30 moves the second imaging unit 23 and the line sensor 15 also sends an image signal. Thus, drive control and image processing are changed. Since these changes can be easily understood from the difference in the above configuration, detailed description thereof will be omitted.

According to such a substrate appearance inspection apparatus 51, the inspection position M is illuminated by the line light source 101 at a predetermined incident angle, and the light from the inspection position M is condensed along the surface C while being condensed by the deflection element 10. Is biased to. Then, the light emitted in the direction corresponding to the arrangement position of the first imaging unit 22 and the second imaging unit 23 is simultaneously imaged on the line sensors 6 and 15 by the imaging lenses 5 and 14, respectively.
For this reason, images of light traveling in two different directions from the inspection position M are simultaneously captured by the line sensors 6 and 15 and sent to the control unit 33 as image signals.
Therefore, a compact apparatus can be configured by simple uniaxial movement, and an apparatus with high inspection efficiency that simultaneously acquires two types of images can be obtained.
Further, since the collimating lens 401 can be fixed, the movable part becomes compact, and a cheaper and faster inspection apparatus can be configured. Also in the first embodiment, it is possible to configure with one collimating lens including the collimating lenses 2 and 4, and thus the same effect can be obtained in the first embodiment.

[Third Embodiment]
An appearance inspection apparatus according to a third embodiment of the present invention will be described.
FIG. 5 is a schematic configuration diagram of an appearance inspection apparatus according to the third embodiment of the present invention.
The substrate appearance inspection apparatus 52 (appearance inspection apparatus) of the present embodiment replaces the illumination unit 11, the imaging unit 12, and the control unit 32 of the substrate appearance inspection apparatus 50 of the first embodiment with the collimating lens 2 from the illumination unit 11. 120A (optical unit) from which the collimator lens 4 has been deleted from the imaging unit 12, and a control unit 35. The half mirror 17 (optical path synthesis means), the mirror 16, 18. A collimating lens 401 according to the second embodiment is added. The following description will focus on differences from the first and second embodiments.

  The illumination unit 120A and the imaging unit 120B are separated by a predetermined distance in the illustrated Z-axis direction by a moving mechanism 34 configured similarly to the moving mechanism 30, for example, and are integrated with each optical axis parallel to the illustrated X-axis direction. And is movable in the Z-axis direction in the figure under the control of the control unit 35.

The mirror 16 is for deflecting the illumination light emitted from the light source 1 in the negative X-axis direction toward the half mirror 17.
The half mirror 17 transmits light from the substrate 3 toward the imaging unit 120B, reflects the illumination light deflected by the mirror 16, and synthesizes the illumination light on an optical path along which the light from the substrate 3 travels. It is to lead to. For example, a configuration such as a half mirror that transmits and reflects illumination light and light from the substrate 3 by 50% can be employed.

The mirror 18 is for bending the optical path by deflecting the illumination light synthesized by the half mirror 17 and the light from the substrate 3. Therefore, in this embodiment, unlike the first and second embodiments, the optical axes of the illumination unit 120A and the imaging unit 120B are directed in a direction parallel to the arrangement direction of the substrate 3.
The collimating lens 401 is disposed on the optical path between the deflection element 10 and the mirror 18.

  The control unit 35 has substantially the same configuration as the control unit 32, and the diffracted light that satisfies the Bragg condition is output from the line sensor 6 when the moving mechanism 34 moves through the illumination unit 120A and the imaging unit 120B. The drive control and the image processing are changed corresponding to the difference in the configuration such as the image signal. Since these changes can be easily understood from the difference in the above configuration, detailed description thereof will be omitted.

According to such a configuration, as shown in FIG. 5, the divergent light emitted from the light source 1 of the illumination unit 120 </ b> A is deflected by the mirror 16, partially reflected by the half mirror 17, and directed toward the mirror 18. Then, the light is deflected by the mirror 18, travels on a plane separated from the surface C by a distance x ₃ toward the negative Z-axis direction, and enters the collimator lens 401. Then, into a parallel light flux by the collimator lens 401, while being focused by the deflection element 10, for example, be deflected from the surface C in a direction inclined by an angle theta _B, it is irradiated as illumination light linear at the test position M.
Of the light reflected at the inspection position M, the diffracted light emitted in the same direction as the angle θ _B returns to the reverse path of the illumination light, passes through the deflecting element 10, the collimating lens 401, and the mirror 18, and is half The mirror 17 is reached. Then, the light passes through the half mirror 17 and enters the imaging lens 5 and forms an image on the line sensor 6.
Therefore, the line sensor 6 can always acquire image information of diffracted light that satisfies the Bragg condition.
When the angle θ _B satisfying the Bragg condition is different, such as when measuring different types of substrates 3, or when searching for the angle θ _B satisfying the Bragg condition, the moving mechanism 34 is driven to illuminate the illumination light. the position x ₃ incident on the deflection element 10 and a variable, carried out by changing the angle theta _B.

  In this embodiment, since the optical path is bent by the mirror 18, the degree of freedom of the arrangement position of the optical unit with respect to the substrate 3 can be improved, and there is an advantage that downsizing and downsizing can be achieved. That is, since the optical path in the optical unit is parallel to the scanning direction X of the substrate 3, the volume of the apparatus can be reduced.

Also changing the angle theta _B, rather than to move the illumination unit 120A and the imaging unit 120B, instead, a mirror 18 may be moved in the X-axis direction.
In this case, since the movement load can be reduced, the apparatus can be reduced in size.

[Fourth Embodiment]
An appearance inspection apparatus according to a fourth embodiment of the present invention will be described.
FIG. 6 is a schematic configuration diagram of an appearance inspection apparatus according to the fourth embodiment of the present invention.
The substrate appearance inspection apparatus 53 (appearance inspection apparatus) of the present embodiment uses the substrate appearance inspection apparatus 52 of the third embodiment to observe diffracted light that satisfies the Bragg condition and other light, such as specular reflection light. Further, observation of other diffracted light, scattered light, etc. can be switched, and the mirror moving mechanism 38 (optical path switching means) and the mirror 19 are added to the substrate appearance inspection device 52 of the third embodiment. And a control unit 37 is provided in place of the control unit 35. Hereinafter, a description will be given focusing on differences from the first to third embodiments.

The mirror moving mechanism 38 is a mechanism for moving the mirror 16 of the third embodiment forward and backward with respect to the optical path of the illumination unit 120A. For example, an electromagnetic solenoid mechanism that is advanced and retracted by the control unit 37 can be adopted. . The advancing / retreating direction may be an appropriate direction, but in the present embodiment, it is the illustrated Z-axis direction.
Mirror 19, the illumination light when the mirror 16 is retracted from the optical path of the illumination unit 120A, and deflected toward the collimator lens 401, along the plane C into the plane of the distance x _1, the collimator lens 401, the deflecting element 10 It is made to enter.

  The control unit 37 has substantially the same configuration as the control unit 32, and the moving mechanism 34 moves the illumination unit 120A and the imaging unit 120B, and the mirror moving mechanism 38 switches the position of the mirror 16 according to the setting conditions. The configuration in which the image information output from the line sensor 6 according to the arrangement position of the mirror 16 is diffracted light that satisfies the Bragg condition, or other light such as specularly reflected light, diffracted light, and scattered light. Corresponding to these differences, drive control and image processing are changed. Since these changes can be easily understood from the difference in the above configuration, detailed description thereof will be omitted.

According to such a configuration, as illustrated in FIG. 6, when the mirror 16 is present on the optical path of the light source 1 of the illumination unit 120 </ b> A by the mirror moving mechanism 38, the substrate appearance inspection apparatus 52 of the third embodiment and A similar operation is performed, and a diffraction image satisfying the Bragg condition is acquired.
If the mirror moving mechanism 38 to retract the mirror 16 from the optical path, the illumination light emitted from the light source 1 is deflected by a mirror 19, at a distance x ₁ from the plane C, enters the collimator lens 401, the deflecting element 10 Then, the inspection position M is illuminated by being deflected to an angle that forms an angle θ _i with the surface C.
Therefore, light from the inspection position M, the angle theta _B direction of the light, deflecting element 10, a collimator lens 401, a mirror 18, is focused on the line sensor 6 by the imaging lens 5 passes through the half mirror 17.
As described above, the mirror 16 of this embodiment that is movably held by the mirror moving mechanism 38 constitutes an optical path switching means that changes the incident direction of the illumination light together with the mirror moving mechanism 38. Therefore, various light such as specularly reflected light, diffracted light, and scattered light can be selected according to the values of the angles θ _i and θ _B , and defect extraction and defect determination are performed according to the image information. Can do.
For example, when θ _i = θ _B , two types of image information of regular reflection light and diffracted light satisfying the Bragg condition can be easily and quickly switched and acquired. Therefore, the inspection efficiency can be improved and the functionality of the apparatus can be enhanced.

In the present embodiment, as in the third embodiment, when changing the angle theta _B, the illumination unit 120A by the moving mechanism 34 may be moved in synchronism with the imaging section 120B, moved independently, The distances x ₁ and x ₃ may be varied independently.

In the above description of each embodiment, an example in which there are two optical units has been described, but three or more optical units may be provided as necessary.
Further, it is sufficient that at least one optical unit moves relative to the subject. For example, a configuration in which any of the optical units in the above embodiments is deleted or a configuration in which the moving mechanism is deleted from one of the optical units is also included in the present invention.

  In the above description, the example in which the imaging direction is fixed and a two-dimensional image of the subject is acquired and then the angle of the imaging direction is changed to perform the next inspection has been described. It is also possible to change the imaging direction and change the imaging direction, store the image signal in the image memory, and then move the inspection position to repeat the imaging.

  In the description of the second embodiment, the incident angle of the illuminating unit without the deflection element is described as being constant. However, the linear light source 101 is held by a rotating mechanism so that the incident angle can be varied. Also good. In this case, since the line-shaped light source 101 is close to the substrate 3, even if a rotation mechanism is provided, a small device configuration can be obtained.

  In the description of the second to fourth embodiments, the description has been given of the example in which one collimator lens is disposed between two imaging units or between the imaging unit, the illumination unit, and the deflection element. As in the embodiment, two collimating lenses may be arranged in each optical path.

  In the description of the third and fourth embodiments, an example in which a half mirror is used as the optical path combining unit has been described. However, the optical path combining unit is not limited to this. For example, when the polarization directions of the illumination light and the light from the subject are different, for example, a polarization beam splitter that reflects the illumination light and transmits the light from the subject is employed corresponding to each polarization direction. You can also

  In the fourth embodiment, the example in which the optical path switching unit switches the incident direction of the illumination light has been described. However, the optical path switching unit is provided in the optical path between the deflection unit and the imaging unit, and an image is captured by the imaging unit. The imaging direction of light from the subject may be switched.

  In the above description, there is a portion described as if an infinite optical system is used. However, the present invention is not limited to this, and a finite system can be used if the numerical aperture is sufficiently small.

  Moreover, each component in said description can be implemented in combination as appropriate within the scope of the technical idea of the present invention, if technically possible. For example, the configuration of the illumination unit 11 may be replaced with the configuration of the line light source 101.

1 is a schematic configuration diagram of an appearance inspection apparatus according to a first embodiment of the present invention. It is a figure which shows an example of the deflection | deviation element which can be used for the external appearance inspection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the other example of the deflection | deviation element which can be used for the external appearance inspection apparatus which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of the external appearance inspection apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the external appearance inspection apparatus which concerns on the 3rd Embodiment of this invention. It is a schematic block diagram of the external appearance inspection apparatus which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1 Light source 2, 4, 401 Collimate lens 5, 14 Imaging lens 3 Substrate (subject)
6, 15 Line sensor (line image sensor)
10 Deflection element 11 Illumination unit (optical unit)
12, 120 Imaging unit (optical unit)
16 mirror (light path switching means)
17 Half mirror (light path combining means)
22 1st imaging part (optical unit)
23 Second imaging unit (optical unit)
30, 31, 34 Moving mechanism 38 Mirror moving mechanism (optical path switching means)
50, 51, 52, 53 Substrate visual inspection device 70 Illumination light 71 Detection light 101 Linear light source 111 Cylindrical lens (lens or lens group having power only in one axis direction)
112 concave mirror

Claims (8)

And at least one optical unit including an illuminating unit that generates illumination light to irradiate the subject, or an imaging unit that forms an image by imaging light from a line-shaped inspection position of the subject on a line imaging device, and the optical unit An appearance inspection apparatus for performing an appearance inspection of the subject by moving at least one of the units and the subject relative to each other and changing an inspection position,
A deflection that is arranged on an optical path between the optical unit and the subject and deflects light from the line inspection position of the subject or light to the line inspection position of the subject in a predetermined direction. An appearance inspection apparatus comprising: an element; and a moving mechanism that relatively moves at least one of the optical units in a direction orthogonal to an optical path direction in the optical unit and a longitudinal direction of the line inspection position.   The appearance inspection apparatus according to claim 1, wherein the deflecting element includes a lens or a lens group having power only in one axial direction.   The visual inspection apparatus according to claim 1, wherein the deflecting element is formed of a concave mirror having power only in one axial direction. The at least one optical unit is composed of two optical units of the illumination unit and the imaging unit,
The visual inspection apparatus according to claim 1, wherein the two optical units are held by moving mechanisms that can move independently. The at least one optical unit is composed of two optical units of the illumination unit and the imaging unit,
On the optical path between the two optical units and the deflection element, optical path synthesis that guides the light traveling from the subject along the same optical path as the illumination light from the illumination unit to the subject to the imaging unit. The visual inspection apparatus according to claim 1, further comprising means.   Optical path switching means for switching an incident direction of illumination light by the illuminating unit or an imaging direction of light from the subject imaged by the imaging unit on any optical path between the two optical units and the subject. The visual inspection apparatus according to claim 5, further comprising: The at least one optical unit is composed of two optical units of the illumination unit and the imaging unit,
The visual inspection apparatus according to claim 1, wherein the deflection element includes two deflection elements having different configurations according to the two optical units. The at least one optical unit is composed of a plurality of optical units each including the imaging unit,
The appearance inspection apparatus according to claim 1, wherein the illumination unit irradiates the subject with illumination light without passing through the deflection element.

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