JP2011007710A - Inspection device, inspection method and inspection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly inspect an inspecting object having a plurality of protrusions.SOLUTION: The inspection device includes a transparent table 12 mounted with an inspecting object A, a light irradiation section for radiating a light pattern, where light intensity varies periodically from a lower surface of the table 12; an imaging section 22 for photographing the inspecting object A irradiated with the light pattern from the lower surface of the table 12; an image processing section 103 for processing an image of the inspecting object A and generating surface shape data, indicating a three-dimensional shape of the surface of the inspecting object A; a center value determining section 102 for determining the center value of the values, indicating a position to the top surface of the table 12 in each of the plurality of protrusions in the inspecting object A, indicated by the surface shape data; and a determination section 101 for determining whether the distribution of respective central values in the plurality of protrusions establishes a preset reference.

Description

  The present invention relates to an inspection apparatus that inspects an inspection object including a plurality of protrusions, such as an electronic component including a plurality of terminals.

  Conventionally, various shape inspection apparatuses that measure the shape of an inspection object such as an electronic component and determine whether it is acceptable have been proposed. For example, an apparatus that scans the surface of an inspection object with a laser beam using a laser displacement sensor and measures the undulations on the surface of the inspection object is known (for example, see Patent Document 1). According to this apparatus, when measuring the shape of the inspection object over a wide range, the laser light is scanned over the inspection range of the surface of the inspection object, and the inspection object is detected by changing the distance between the laser displacement sensor and the measurement spot. Pass / fail judgment is performed by detecting the deformation of the object.

  In the shape inspection apparatus using the laser described above, it is necessary to scan the laser beam over the entire surface of the inspection object, and thus it takes time to acquire surface information of the inspection object. In view of this, a shape measuring apparatus using a pattern projection method has been proposed that generates surface shape data of an inspection object from an image taken by applying light whose intensity changes periodically to the inspection object (for example, Patent Document 2). According to this apparatus, a wide range of surface information of the inspection object can be instantaneously acquired from an image.

JP-A-7-19822 JP 2008-261679 A

  However, for example, when a large number of inspection objects are continuously inspected as in an inspection of an electronic component production line, further reduction in time required for measurement and determination is required. Further, for example, when determining the quality of a complicated and fine shape as in the shape inspection of a terminal of an electronic device, both the inspection accuracy and the inspection speed must be improved. Therefore, an object of the present invention is to provide an inspection apparatus, an inspection program, or an inspection method capable of quickly inspecting an inspection object having a plurality of protrusions.

  An inspection apparatus disclosed in the present application is an inspection apparatus that inspects an inspection object including a plurality of protrusions arranged in at least one direction, and is placed on a transparent table on which the inspection object is placed and an upper surface of the table From the lower surface of the table, the light irradiation unit that irradiates the inspection object with a light pattern in which light intensity periodically changes from the lower surface of the table, and the inspection object irradiated with the light pattern. An image capturing unit that captures an image, an image processing unit that processes an image of the inspection object captured by the image capturing unit, and generates surface shape data representing a three-dimensional shape of the surface of the inspection object, and the image processing A representative for determining a representative value of a value indicating a position with respect to the upper surface of the table in each of the plurality of protrusions in the inspection object represented by the surface shape data generated by the section A determination unit includes a determination section for determining the distribution of the representative value satisfies the predetermined standard in the plurality of protrusions, respectively.

  In the above configuration, the surface shape data is generated based on the image photographed from the lower surface in a state where the inspection target placed on the upper surface of the transparent table is irradiated with the light pattern from the lower surface. Therefore, the three-dimensional shape of the surface of the inspection object represented by the surface shape data can be captured with the upper surface of the table as a reference. Using this, the representative value determining unit determines a representative value of a value indicating a relative position with respect to the upper surface of the table for each of the plurality of protrusions. The determination unit determines whether or not the distribution of distances from the upper surface of the table at the representative points of the protrusions satisfies a predetermined criterion. Thereby, the quality of the formation degree of the several projection part in a test target object can be determined by a simple process. As described above, the pattern projection and photographing through the transparent table, and the determination and determination of the representative point based on the table upper surface enable quick determination with simple processing.

  In the inspection apparatus, the light irradiation unit includes a phase change unit that changes a phase of the intensity change in the light pattern irradiated onto the inspection target, and the imaging unit emits a plurality of light patterns having different phases. Each of the inspected inspection objects is photographed, and the image processing unit obtains height information of the inspection object using a phase shift method according to patterns appearing in a plurality of images having different phases photographed by the imaging unit. The aspect which calculates and produces | generates the said surface shape data may be sufficient.

  In the inspection apparatus, the representative value determining unit uses a point included in an area where the distance from the upper surface of the table in the protrusion is smaller than the surrounding area as a representative point, and the representative point from the upper surface of the table. The distance may be the representative value.

  In the inspection apparatus, the representative value determination unit uses a point included in a region where the surface of the protrusion is in contact with the upper surface of the table as a representative point in the protrusion, and the distance from the upper surface of the table to the representative point. May be the representative value.

  In the inspection apparatus, the representative value determination unit may calculate an average value of distances from the upper surface of the table in the protrusion, and may use the average value as the representative value of the protrusion.

  In the inspection apparatus, the determination unit calculates a difference between a maximum value and a minimum value as a flatness in the distribution of the representative values in a plurality of protrusions, and compares the flatness with a preset reference value. By this, the aspect which performs the said determination may be sufficient.

  In the inspection apparatus, the determination unit may further calculate a distance between the plurality of protrusions from the surface shape data, and further determine whether the distance satisfies a preset criterion.

  In the inspection apparatus, the determination unit may further determine whether the shape of the main body that supports the plurality of protrusions represented by the surface shape data satisfies a preset criterion.

  In the inspection apparatus, the determination unit further calculates an inclination angle of the plurality of protrusions with respect to the upper surface of the table from the surface shape data, and further determines whether the inclination angle satisfies a preset criterion. You may judge.

  An inspection method disclosed in the present application is an inspection method for inspecting an inspection object including a plurality of protrusions arranged in at least one direction, and the inspection object is placed on the upper surface of a transparent table. A light irradiation step of irradiating a light pattern whose light intensity periodically changes from the lower surface, an imaging step of photographing the inspection object irradiated with the light pattern from the lower surface of the table, and a computer An image processing step for processing the image of the inspection object photographed in a process to generate surface shape data representing a three-dimensional shape of the surface of the inspection object; and the computer is generated in the image processing step. In each of the plurality of projections represented by the surface shape data, a representative value determining step for determining a representative value indicating a position with respect to the upper surface of the table; Computer, and a determination step of determining whether the distribution of the representative values in the plurality of protrusions satisfies a predetermined standard.

  An inspection program disclosed in the present application is an inspection program for inspecting an inspection object including a plurality of protrusions arranged in at least one direction, and the transparent table on which the inspection object is placed, and the upper surface of the table. The light irradiation unit that irradiates the inspection object with a light pattern in which the intensity of light periodically changes from the lower surface of the table, and the inspection object irradiated with the light pattern is imaged from the lower surface of the table. An image processing unit that processes an image of the inspection object photographed by the image capturing unit and generates surface shape data representing a three-dimensional shape of the surface of the inspection object. In each of the input processing for receiving the surface shape data and the plurality of protrusions represented by the surface shape data, the position of the protrusion relative to the upper surface of the table A representative value determining process for determining a representative value of the values indicating the distribution of the representative values in the plurality of protrusions to perform the determination processing of determining meets preset criteria into the computer.

  According to the present disclosure, it is possible to quickly inspect an inspection object including a plurality of protrusions.

The figure which shows the outline of a structure of the test | inspection apparatus concerning 1st Embodiment. The figure which shows the further detailed structural example of the measurement part in FIG. A diagram schematically showing the projection and imaging of a striped light pattern onto the inspection object Flowchart showing an example of processing for three-dimensional measurement of an inspection object A graph representing a phase change of brightness at position (z, y) Functional block diagram showing an example of the configuration of the computer 1 Flow chart showing an example of inspection processing Diagram showing examples of inspection objects Histogram showing an example of the distribution of the distance h from the sample surface at the terminal Diagram showing representative points at terminals The flowchart which shows another example of the process which performs the three-dimensional measurement of a test target object The figure for demonstrating the example of the inclination-angle determination of a terminal

  Embodiments of the present invention will be specifically described below with reference to the drawings.

(First embodiment)
[Configuration of inspection system]
FIG. 1 is a diagram schematically illustrating the configuration of the inspection apparatus according to the first embodiment. An inspection apparatus 100 illustrated in FIG. 1 includes a measurement unit 5 that measures the shape of an inspection object, a control unit 4 that controls the measurement unit 5, and a computer 1 that is connected to the measurement unit 5 and the control unit 4. The computer 1 is connected to a monitor 2 and an input device 3 (a mouse 3a and a keyboard 3b). An inspection apparatus 100 shown in FIG. 1 is an apparatus that measures the shape of an inspection object and determines the quality of the shape. The measuring unit 5 is controlled by the control unit 4 to measure the surface shape of the inspection object, and the computer 1 determines the quality of the inspection object based on the measurement data, and stores or outputs the result (inspection result). . For example, the inspection apparatus 100 can be used to determine the quality of a completed electronic component in an electronic component production line. Hereinafter, although the case where the inspection apparatus 100 is used for shape determination of an electronic component will be described, the inspection object of the inspection apparatus 100 is not limited to the electronic component.

  FIG. 2 is a diagram illustrating a more detailed configuration example of the measurement unit 5 of FIG. In the example illustrated in FIG. 2, the measurement unit 5 includes a projection projector 21 (an example of a light irradiation unit), an imaging unit 22, a table 12, and a drive unit 13 that moves the table 12. The table 12 is a transparent glass plate and is provided on the upper surface of the housing of the measurement unit 5. An inspection object A is placed on the upper surface of the table 12. Under the table 12, a projection projector 21 and an imaging unit 22 are provided. The projection projector 21 irradiates the inspection object A with a striped light pattern from the lower surface of the table 12. The imaging unit 22 images the light pattern projected onto the inspection object A from the lower surface of the table 12.

  The inspection apparatus 100 shown in FIG. 2 uses a lattice projection method classified as triangulation for acquiring a three-dimensional shape. When the striped light pattern is projected onto the inspection object A, the stripe pattern is deformed in accordance with the shape of the inspection object A. Therefore, by measuring the deformation amount of the stripe pattern in the image of the inspection object A The shape can be measured. Hereinafter, each part of the inspection apparatus 100 will be described in detail. The upper surface of the table 12 is a surface on which the inspection object A is set (hereinafter referred to as a sample surface 12a). Here, the axes orthogonal to each other in the sample surface 12a are defined as the XY axes, and the axis perpendicular to the sample surface 12a is defined as the Z axis. The drive unit 13 may include an XY drive unit 13 that moves the table 12 in the X-axis direction and the Y-axis direction, and a Z drive unit 13 that moves the table 12 in the Z-axis direction. Moreover, it can also be set as the structure which moves the projection project 21 and the imaging part 22 instead of the structure to which the table 12 is moved.

  The projection projector 21 is a unit that irradiates the inspection object A beyond the sample surface 12a with a striped light pattern in which the intensity of light periodically changes. Therefore, in the projection projector 21, the light source 6, the condenser lens 7, the grid 8, and the telecentric lenses 9 and 10 are arranged in order.

  For the light source 6, for example, an LED is preferably used from the viewpoint of cost. In addition, a halogen lamp, a laser light source, or the like can be used as the light source 6. The condensing lens 7 condenses the light from the light source 6 and brings it close to parallel light. The grid 8 turns the light close to the parallel light into striped light whose intensity changes periodically.

  The grid 8 includes a film having a sine wave or cosine wave pattern, for example. As the film, for example, a lattice film having a sine wave pattern with a wavelength of about 50 μm to 500 μm can be used.

  The grid pattern of the grid may be a grid pattern in which two types of intensity of light and dark appear alternately, or has light intensity corresponding to a cosine wave or a sine wave when changing from light to dark and from dark to light. It may be a pattern. By projecting light having a cosine wave or sine wave intensity change onto the inspection object A in this way, height analysis can be performed on all the pixels photographed by the imaging unit 22. The light pattern may be a multiple ring pattern or a checkered pattern.

  The means for generating the light pattern is not limited to the above film. For example, a striped light pattern whose intensity periodically changes can be generated using a liquid crystal panel.

  Further, by providing a stepping motor on the grid 8, the position of the stripe of the light pattern can be moved (shifted). The driving of the grid 8 by the stepping motor is controlled by a signal from the control unit 4, for example. For example, the control unit 4 or the measurement unit 5 can be provided with a microstepping driver that drives a microstepping motor. By using the microstepping driver, it is possible to shift the optical pattern with high resolution. The computer 1 can set the driving conditions of the grid 8 for the control unit 4.

  The striped light pattern that has passed through the grid 8 passes through the telecentric lens unit 11 and is applied to the inspection object A on the sample surface 12a. The telecentric lens unit 11 forms a telecentric optical system by the telecentric lenses 9 and 10. The telecentric optical system formed by the telecentric lenses 9 and 10 can be an image side telecentric optical system, an object side telecentric optical system, or a both side telecentric optical system. For example, in the case of a bilateral telecentric optical system, the telecentric lenses 9 and 10 are arranged so that the main intersection line is parallel to the lens optical axis K on both the object side and the image side.

  In the image by the light exiting the telecentric lens unit 11, the subject size hardly changes within the depth of field. That is, the stripe interval in the light emitted from the telecentric lens unit 11 hardly changes in the light traveling direction. Therefore, in the subsequent process of the image of the inspection object A that has been irradiated with the light pattern, the process of correcting the fringe interval change becomes unnecessary.

  The imaging unit 22 includes a CCD camera 15 and a telecentric lens unit 17. The telecentric lens unit 17 includes telecentric lenses 16 and 18. The CCD camera 15 photographs the inspection object A irradiated with the striped light pattern. Note that the imaging apparatus is not limited to the CCD camera 15, and for example, a CMOS sensor, a line sensor, or the like can be used. Since the CCD camera 15 captures an image by light passing through the telecentric lens unit 17, an image that does not require correction of the fringe interval can be obtained.

  As described above, the measurement unit 5 of this embodiment is configured by combining the projection projector 21 including the light source 6, the grid 8, and the telecentric lens unit 11 with the imaging unit 22 including the CCD camera 15 and the telecentric lens unit 17. It becomes possible to acquire high-resolution three-dimensional information with resolution and height resolution of several microns. For this reason, the measurement unit 5 can obtain, for example, three-dimensional shape data (surface shape data) suitable for evaluation of terminals of electronic components. In addition, the structure of the measurement part 5 is not restricted to the structure shown in FIG. For example, it may be configured to include a plurality of projection projectors that irradiate light patterns from different directions. The imaging unit 22 does not necessarily need to use a telecentric optical system. For example, the imaging unit 22 can take a wide projection surface by irradiating a light pattern whose width increases in the light traveling direction. Further, the imaging unit 22 may be configured to perform tilt projection in which the light pattern is projected without tilting the grid with respect to the projection plane.

[Surface shape data calculation example]
Next, a method for calculating the surface shape data of the inspection object A using the grid projection method will be described. FIG. 3 is a diagram schematically illustrating the state of projection and photographing of a striped light pattern onto the inspection object A in the measurement unit 5. As shown in FIG. 3A, the projection projector 21 irradiates the inspection object A with a striped light pattern whose intensity periodically changes in the direction of the arrow D. FIG. 3B is a diagram illustrating an example of a striped pattern. On the sample surface, a striped pattern whose intensity changes periodically in the Y-axis direction is projected. On the surface of the inspection object A, the striped pattern is deformed according to the surface shape of the inspection object A. FIG. 3C is a diagram illustrating an example of an image captured by the imaging unit 22. A state in which the stripe pattern is deformed in accordance with the surface shape of the inspection object A appears in the image. The relationship between the stripe pattern deformation amount x and the height h of the inspection object A is calculated as h = x / tan α where α represents each projection of light onto the sample surface 12a (FIG. 3D).

  Here, in order to perform measurement with higher accuracy, a phase shift method can be applied to the phase analysis. In the measurement by the phase shift method, the fringe pattern projected by the projection projector 21 is shifted by ¼ period, and four fringe images are taken to perform phase analysis.

  FIG. 4 is a flowchart illustrating an example of processing in which the inspection apparatus 100 illustrated in FIGS. 1 and 2 performs three-dimensional measurement of the inspection object A using the phase shift method. In the example shown in FIG. 4, when the inspection object A is set on the sample surface 12 a (S 1), the measurement object 5 irradiates the inspection object A with light in a striped pattern (lattice pattern) from under the table 12. Thereby, the lattice pattern is projected onto the inspection object A. An image of the inspection object A onto which the lattice pattern is projected is taken from the lower surface of the table 12 by the imaging unit 22 (S2). Here, the case where the light of the striped pattern which shows the change equivalent to a cosine wave is irradiated is demonstrated. In this photographed image, a striped pattern deformed according to the surface shape of the inspection object A is shown. Further, the projection projector 21 projects light obtained by shifting a cosine wave stripe pattern by ¼ period, and the imaging unit 22 takes an image of a stripe pattern in which four phases are shifted by ¼ period. To do. Here, image data captured by the measurement unit 5 is sent to an image processing unit (described later) of the computer 1. The image processing unit of the computer 1 performs phase analysis by processing the image data (S3). In the phase analysis, the phase θ of the light pattern projected at the position (coordinates (x, y)) of each pixel in the image is calculated. The brightness at the position (x, y) is represented by the following formula (1).

a is a coefficient indicating the amplitude of the brightness of the stripes at that position, and b is a coefficient indicating the brightness offset amount b at that position. FIG. 5 is a graph showing the above formula (1). As shown in FIG. 5, the brightness at the same position (x, y) on the four images is represented by the following formula (2): I ₀ , I ₁ , I ₂ , I ₃

Therefore, the phase θ at (x, y) can be calculated by the following equation (3).

  The phase θ shown in the above equation (3) does not depend on the coefficients a and b. Thus, since the amplitude a term of the brightness of the fringe and the offset amount b term of the brightness are canceled in the calculation formula, it is difficult to be influenced by disturbance light, and highly accurate measurement is possible. Therefore, by using the phase shift method, it is possible to perform measurement with accuracy suitable for fine inspection such as shape inspection of terminals of electronic components.

In this way, the phase θ of each position (x, y) is calculated. In a line (equal phase line) obtained by connecting points having the same phase θ, a variation corresponding to the shape of the inspection object A appears as in the striped pattern shown in FIG. Therefore, the deformation amount (phase difference) of the phase θ at each position is calculated (
By converting this phase difference into height units (S5 in FIG. 5), a value indicating the height of the inspection object A at each position is obtained. That is, data indicating the three-dimensional shape of the surface of the inspection object A is obtained.

  In the process S4, reference phase data recorded in advance in the computer 1 is used when calculating a phase difference indicating how much the phase θ of each position changes depending on the inspection object A. For example, an image when a striped pattern of the same cosine wave is projected onto the sample surface 12a on which the inspection object A is not placed is taken in advance, and data indicating the phase θ of each position on the sample surface 12a is calculated, and the reference It can be recorded as phase data. The computer 1 calculates the phase difference by calculating the difference between the reference phase data representing the phase θ at each position on the sample surface 12a and the data representing the phase θ at each position when the inspection object A is placed. Can be calculated. Since the phase difference at each position is a value corresponding to the distance (height) between the surface of the inspection object A and the sample surface 12a, it can be converted into data indicating the height (S5).

  In the present embodiment, since the light pattern is projected and photographed in a state where the inspection object A is placed on the upper surface of the table 12, the floating amount from the upper surface of the table 12 can be obtained as height information. Therefore, for example, assuming that the upper surface of the table 12 is the mounting substrate, it is possible to determine the floating amount when mounting the electronic component.

  As described above, in the phase shift method, the phases of intensity changes in the light pattern irradiated onto the inspection object A are made different, and data of a plurality of images corresponding to the respective phases are acquired. Using the brightness at the same position (x, y) of the plurality of images, the phase θ of the light pattern projected at the position (x, y) is obtained, and the principle of triangulation is used based on the phase θ. To calculate the height.

  Note that the method for acquiring height information using the phase shift method is not limited to the above example. For example, the number of images to be captured is not limited to four. If three images are taken, the phase θ can be calculated, and four or more images can be taken to improve accuracy. The above formulas (1) to (3) used for calculating the phase θ are also examples, and the phase θ can be calculated using other formulas.

  The computer 1 processes the data indicating the three-dimensional shape of the surface of the inspection object A obtained by using the phase shift method in this way, thereby inspecting the inspection object A (S6). .

[Computer configuration]
FIG. 6 is a functional block diagram showing an example of the configuration of the computer 1 for executing this inspection process. In the configuration illustrated in FIG. 6, the computer 1 includes a determination unit 101, a representative value determination unit 102, an image processing unit 103, a measurement unit 104, and a user interface unit (UI unit) 105. These functional units are realized, for example, when the processor of the computer 1 executes a predetermined program stored in the memory. From the viewpoint of executing processing at high speed, for example, the function of the image processing unit 103 is realized by hardware (image processing board) dedicated to image data processing provided separately from the processor of the computer 1. You can also. Examples of such hardware include a GPU (Graphics Processing Unit), a VPU (Visual Processing Unit), a geometry engine, and other ASIC (Application Specific Integrated Circuit).

  The image processing unit 103 receives the image captured by the imaging unit 22 and generates data indicating the three-dimensional shape of the inspection object A. The surface shape data is represented by, for example, a value indicating a height (for example, a distance from the sample surface 12a) at each position (x, y) on the XY plane. For example, the image processing unit 103 executes the phase analysis (S3), phase difference calculation (S4), and height unit conversion (S5) processing of FIG. 4 on the image data sent from the imaging unit 22. Thus, surface shape data can be generated. The image processing unit 103 can store the generated surface shape data in a memory on the computer 1 so that the representative value determining unit 102 and the determining unit 101 can use the surface shape data.

  The representative value determination unit 102 determines the position of the protrusion with respect to the upper surface (sample surface 12a) of the table 12 for each of the plurality of protrusions included in the inspection object A represented by the surface shape data generated by the image processing unit 10. A representative value of the indicated value is determined. Here, the inspection object A is, for example, an electronic component with a plurality of terminals, and when it is determined whether or not all the terminals are securely in contact with the substrate when the electronic component is mounted on the substrate, By using the representative value of the position with respect to the sample surface 12a for each protrusion of the representative value determining unit 102 for the determination, it is possible to make a quick determination. In addition, since the relative position with respect to the sample surface 12a can be compared between the protrusions, it is possible to determine the degree of variation in the formation positions of the plurality of protrusions on the basis of the sample surface 12a.

  For example, the representative value may be a representative value of the distance from the sample surface 12a, or may include information in the XY directions in addition to the distance from the sample surface 12a. Also, one point on the surface of the protrusion may be a representative point, the coordinates of the representative point may be a representative value, or a statistically calculated value such as the average distance from the sample surface 12a on the surface of the protrusion may be representative. It may be a value.

  The representative value determination unit 102 specifies a rough area of each protrusion using area data indicating an area in which each protrusion is included in the surface shape data, performs data analysis for each area, and performs the protrusion analysis. A representative value for each can be determined. The area data indicating the area including each protrusion can be acquired from, for example, design data of the inspection object such as CAD data, or can be acquired by inputting the position of the protrusion from the user.

  For example, when the surface shape data is image data indicating the distance from the sample surface 12a at each position (x, y) on the XY plane, the area data is data representing an area where each protrusion is arranged on the XY plane. It can be. In this case, for example, the image data or the area data may be adjusted (aligned) by pattern recognition processing such as template matching so that each protrusion represented by the image data enters each area of the area data.

  The representative value determining unit 102 determines the representative value of the relative position between the sample surface 12a and the protrusion surface for each protrusion. The representative value determining unit 102 can calculate the representative value using, for example, the sample surface 12a and the distance distribution in the protrusion. Specifically, for each protrusion, the coordinates of the representative point in the protrusion are determined based on the distribution of the distance from the sample surface 12a in the protrusion, and the distance from the sample surface 12a at the representative point is a representative value. Can do. In determining the representative point, the representative value determining unit 102 determines a point included in the region where the distance from the sample surface 12a is smaller than the surrounding in the protrusion or the region where the surface of the protrusion is in contact with the sample surface 12a. It can be a representative point. As an example, the representative value determining unit 102 can calculate the coordinates of the center of gravity of such a region or the point that becomes the center, and can use this coordinate as the representative point. Alternatively, the representative point can be determined from the region having the highest frequency (frequency) in the distribution of the distance between the sample surface 12a and the surface of the protrusion in the protrusion. Furthermore, without determining a representative point, an average value, an intermediate value, or the like of the distance between the sample surface 12a and the protrusion surface in the protrusion can be calculated as a representative value. Thus, the representative value calculated here is a value that represents the distance from the sample surface 12a on the surface of the protrusion for each protrusion.

  The determination unit 101 determines the quality of the shape of the plurality of protrusions using the representative value of each protrusion determined by the representative value determination unit 102. For example, the determination unit 101 calculates a value indicating the relative positional relationship between the plurality of protrusions or a value indicating the positional relationship with respect to the sample surface 12a from the representative value of each protrusion. The determination unit 101 can determine pass / fail based on whether or not the calculated value is within a predetermined range. It is preferable that the data indicating the predetermined range serving as a determination reference of the determination unit 101 is recorded in advance in the memory of the computer 1. Alternatively, it is possible to accept a range of values serving as a criterion for pass / fail determination from the user via the UI unit 105.

  The value indicating the relative positional relationship between the plurality of protrusions and the value indicating the positional relationship between the plurality of protrusions with respect to the sample surface 12a can be calculated from the representative value of each protrusion. For example, the relative positional relationship between the plurality of protrusions is indicated by a value indicating the distribution of the representative values such as the difference between the maximum value and the minimum value of the representative values of the plurality of protrusions, the average value, and the variance. Further, the positional relationship of the plurality of protrusions with respect to the sample surface 12a is indicated by the average, intermediate value, etc. of the representative values in the plurality of protrusions.

  The UI unit 105 is an interface unit that enables information exchange between the user and the computer 1. For example, the UI unit 105 outputs a determination result by the determination unit 101 to the monitor 2 or receives a control instruction of the measurement unit 5 or an instruction of a determination condition of the determination unit 101 from the user via the input device 3.

  The measurement unit 104 outputs a control signal indicating a measurement start instruction, a measurement end instruction, a measurement condition, and the like to the control unit 4. Further, the measurement unit 104 can control the control unit 4 based on a user instruction input via the UI unit 105.

[Inspection processing example 1]
Next, an operation example of the representative value determination unit 102 and the determination unit 101 will be described. FIG. 7 is a flowchart illustrating an example of inspection processing performed by the representative value determination unit 102 and the determination unit 101. Here, as an example, a case will be described in which the inspection object A is an electronic component 30 having a plurality of terminals 32a to 32e as shown in FIGS. 8 (a) to 8 (c). The electronic component 30 shown in FIGS. 8A to 8C includes a plurality of terminals 32a to 32e on the side surface of the main body 31, and these terminals 32a to 32e are bent and extend below the bottom surface. . For example, the electronic component 30 has a structure often found in an FPC connector. When such an electronic component 30 is mounted on a substrate, the lower surfaces of the terminals 32a to 32e are connected to the substrate. Therefore, the bottom surfaces of the terminals 32a to 32e are required to be uniform. Therefore, in the present embodiment, processing for determining the degree of alignment is executed.

  FIG. 8B is a side view of the electronic component 30 as the inspection object A placed on the sample surface 12a of the table 12 with the terminals 32a to 32e facing down. The terminals (32a to) 32e and the terminal 32f are in contact with the sample surface 12a. FIG. 8C is a view of the electronic component 30 placed on the table 12 as viewed from the lower surface of the table 12. As described above, by performing measurement in a state where the electronic component 30 is supported on the table 12 by the terminals 32a to 32e which are the protrusions, it is possible to perform inspection in a state close to the mounted state.

  A light pattern is projected by the projection projector 21 onto the electronic component 30 in the state shown in FIG. 8A and FIG. The captured image is processed by the image processing unit 103, and surface shape data indicating the lower surface shape of the electronic component 30 is generated.

  In S61 of FIG. 7, the representative value determining unit 102 inputs the surface shape data generated by the image processing unit 103. For each of the plurality of terminals 32a to 32e of the electronic component 30 represented by the surface shape data generated by the image processing unit 10, the representative value determining unit 102 represents the representative value of the distance h from the sample surface 12a to the terminal surface. Determine (S62).

  The representative value determination unit 102 refers to, for example, region data indicating the region including each of the protrusions, and determines a representative value for the region of each protrusion in the surface shape data based on the distance h from the sample surface 12a. To do. Regions Ra to Rf surrounded by dotted lines in FIG. 8B indicate regions of the respective protrusions indicated by the region data. Here, as an example, a description will be given of a process in which the representative value determining unit 102 determines the coordinates of the representative point from the region where the distance h from the sample surface 12a is the minimum at each terminal. FIG. 8D is an enlarged view of a portion where the terminal 32e of FIG. 8B is in contact with the sample surface 12a. In the example shown in FIG. 8D, a part of the surface of the terminal 32e is in contact with the sample surface 12a. Here, if the resolution of the height direction measurement by the measurement unit 5 is Δk, in the regions R1 and R2 where the distance h from the sample surface 12a is smaller than Δk, the distance h is all the same value (here, the surface shape data). h = 0). FIG. 9 is a histogram showing an example of the distribution of the distance h at the terminal 32e. In the histogram shown in FIG. 9, since the distance h = 0 is the smallest, the representative value determining unit 102 selects a representative point from the region where the distance h = 0. FIG. 10A is a diagram illustrating an example of the region R where the distance h = 0 at the terminal 32e and the representative point D1. The representative value determining unit 102 calculates, for example, the coordinates of the center of gravity of the region R where the distance h = 0. The coordinates of the center of gravity are the representative point D1.

  Here, the representative value determination unit 102 selects a representative point from an area having the smallest distance h, but the selection of the representative point is not limited to this. For example, the representative point can be selected from a region (for example, W shown in FIG. 9) where the distance h from the sample surface 12a is smaller than a predetermined value. In addition, the representative point can be selected from the distance h having the highest frequency. Further, an average value of the distance h in the region R3 where the distance h from the sample surface 12a is within a predetermined range may be calculated, and this average value may be used as the representative value. A region R3 illustrated in FIG. 10B is an example of a region where the distance h from the sample surface 12a is within a predetermined range. Thus, the average value of the distance h in the region R3 can be used as the representative value.

  The representative value determining unit 102 calculates the coordinates of the representative points for all the terminals 32a to 32e. The determination unit 101 calculates the distribution of the distance h between these representative points (S63 in FIG. 7). Here, as an example of the distribution, the determination unit 101 calculates the flatness (coplanarity) of the terminals 32a to 32e. The flatness is expressed by, for example, the difference between the maximum value and the minimum value of the distance h at the representative points of the terminals 32a to 32e. The determination unit 101 can determine whether the flatness is within a predetermined range or not (S64). Thereby, quick determination processing becomes possible.

[Inspection processing example 2]
FIG. 11 is a flowchart illustrating an example of another inspection process performed by the representative value determination unit 102 and the determination unit 101. In FIG. 11, the processing of S61 to S64 is executed in the same manner as S61 to S64 in FIG. In S65, the representative value determining unit 102 performs edge detection at each of the terminals 32a to 32e, and determines the coordinates of the representative point based on the edge. FIG. 10C is a diagram illustrating an example of detected edges and representative points. Edge detection is, for example, a process of detecting a portion where the distance h changes significantly (where discontinuities are connected in a line) in the surface shape data. When the contours of the terminals 32a to 32e are detected by the edge detection, the representative value determining unit 102 is on the center line of the terminal width M, for example, as shown in FIG. The coordinates of the point D2 at the distance L are calculated and set as the coordinates of the representative point.

  The determination unit 101 calculates the pitch of the terminals 32a to 32e (S66). For example, the determination unit 101 calculates, for each of the terminals 32a to 32e, the distance (pitch) between the representative point of the terminal, the adjacent terminal, and the representative point. The determination unit 101 determines whether the pitch is within a predetermined range (S67).

  The determination unit 101 further makes a comprehensive determination based on the pitch determination result in S67 and the flatness determination result in S64 (S68). For example, the determination unit 101 can determine that both the pitch and the flatness are within a predetermined range and that it is OK, and at least one of them is out of the predetermined range as NG. Thereby, it is possible to make a determination in consideration of the pitch in addition to the flatness. Note that the determination results of the pitch and flatness can be output as they are.

  As described above, the operation example for determining the pitch in addition to the flatness has been described with reference to FIG. 11, but the determination items are not limited thereto. Examples of other determination items will be described below.

[Determination of tilt angle]
The determination unit 101 can also calculate the inclination of the surface of each protrusion indicated by the surface shape data with respect to the sample surface 12a and further determine whether the calculated inclination satisfies a predetermined criterion. The determination unit 101 obtains the contour (edge) of each projection of the surface shape data by, for example, edge detection, selects at least two points in the projection based on this contour, and the line connecting these selected points The angle with respect to the sample surface 12a can be calculated.

  Here, as an example, a calculation example of the inclination of the terminal 32f having a shape as shown in FIG. 12A shows the cross-sectional shape of the terminal 32f on a plane (XZ plane) perpendicular to the sample surface 12a, and FIG. 12B shows a region including the terminal 32f of three-dimensional data (region on the XY plane). It is a figure which shows the example of the edge Ef of the terminal 32f detected in (). In the example shown in FIG. 12B, a rectangular edge Ef is detected as the shape of the terminal 32f on the XY plane. The determination unit 101 is on a line that bisects in the width direction of the terminal 32f, a position P2 that is a predetermined distance L1 from the tip of the terminal 32f, and a position that is on this line and is further away from the point P2 by a predetermined distance L2. And select the point P1 at. The determination unit 101 acquires three-dimensional coordinates including height information at the points P1 and P2 from the surface shape data. The determination unit 101 calculates an angle θ between a line connecting the three-dimensional coordinates of the points P1 and P2 and the sample surface 12a. The determination unit 101 determines pass / fail based on whether the angle θ exceeds a preset reference range.

[Determination of body displacement and deformation]
The determination unit 101 can further determine whether the shape of the main body 31 that supports the plurality of terminals 32a to 32e represented by the surface shape data satisfies a preset criterion. For example, the determination unit 101 determines whether the distance from the sample surface 12a at each point on the surface of the main body 31 facing the sample surface 12a indicated by the three-dimensional shape data is within a predetermined range. Specifically, the determination unit 101 calculates the difference between the distance from the sample surface 12a at each point of the predetermined reference plane and the distance from the sample surface 12a at each point of the main body 31, and the difference is calculated. It can be determined whether the number of points exceeding the threshold, the difference value, etc. are within a predetermined range.

  The process for determining the area of the main body 31 in the three-dimensional shape data can be the same as the process for determining the area of the protrusion.

  As described above, according to the present embodiment, the above-described inspection process of the computer 1 can quickly execute a precise determination such as the determination of the flatness of a terminal in an electronic component. Therefore, the inspection apparatus 100 can be used for terminal shape determination of an electronic component in an electronic equipment production line.

  Further, by using a three-dimensional shape measuring instrument using the grid projection method represented by the measuring unit 5 as a measuring instrument, three-dimensional measurement suitable for inspection of terminals of electronic components can be performed. For example, non-contact measurement is possible by using a lattice projection method. In addition, since data is acquired by surface measurement in which an image including the entire measurement target region is acquired by one imaging operation, measurement can be performed faster than a scanning measurement apparatus using a laser or the like.

  Furthermore, by using the phase shift, the height information can be processed efficiently and quickly, and a highly accurate analysis result can be obtained. As described above, according to the present embodiment, for example, a measuring instrument and a calculation process having a structure suitable for inspection in a production line of an electronic device are provided.

  The application range of the present invention is not limited to the above embodiment. For example, the inspection object is not limited to an electronic component. Moreover, although the case where the three-dimensional shape measuring device using the lattice projection method was used as the measuring device has been described in the above embodiment, the measuring device may be, for example, a pattern projection method other than the above (for example, a gray scale pattern). Or a method of projecting a color pattern), a moire, a focus method, a stereo method, or other methods.

DESCRIPTION OF SYMBOLS 1 Computer 2 Monitor 3 Input device 4 Control part 5 Measurement part 6 Light source 7 Condensing lens 8 Grid 9 Telecentric lens 10 Image processing part 11 Telecentric lens unit 12 Table 12a Sample surface 13 Drive part 15 Camera 16 Telecentric lens 17 Telecentric lens unit 21 Projection projector 22 Imaging unit 30 Electronic component 31 Main body 32a-32e Terminal 100 Inspection apparatus 101 Determination unit 102 Representative value determination unit 103 Image processing unit 104 Measurement unit

Claims (11)

An inspection apparatus that inspects an inspection object including a plurality of protrusions arranged in at least one direction,
A transparent table for placing the inspection object;
A light irradiation unit that irradiates a light pattern in which the intensity of light periodically changes from the lower surface of the table to the inspection object placed on the upper surface of the table;
An imaging unit that photographs the inspection object irradiated with the light pattern from a lower surface of the table;
An image processing unit that processes an image of the inspection object imaged by the imaging unit and generates surface shape data representing a three-dimensional shape of the surface of the inspection object;
A representative value determining unit that determines a representative value of a value indicating a position with respect to the upper surface of the table in each of the plurality of protrusions in the inspection object represented by the surface shape data generated by the image processing unit;
An inspection apparatus comprising: a determination unit that determines whether a distribution of the representative value in each of the plurality of protrusions satisfies a preset criterion. The light irradiation unit includes a phase change unit that changes a phase of the intensity change in the light pattern to be irradiated to the inspection object,
The imaging unit photographs each of the inspection objects irradiated with a plurality of light patterns having different phases,
The image processing unit generates the surface shape data by calculating the height information of the inspection object using a phase shift method according to a pattern appearing in a plurality of images having different phases photographed by the imaging unit, The inspection apparatus according to claim 1.   The representative value determining unit uses a point included in an area where the distance from the upper surface of the table is smaller than the surrounding area in the projection as a representative point, and the distance from the upper surface of the table to the representative point is the representative value. The inspection apparatus according to claim 1 or 2.   The representative value determination unit uses a point included in a region where the surface of the protrusion is in contact with the upper surface of the table in the protrusion as a representative point, and the distance from the upper surface of the table to the representative point is the representative value. The inspection apparatus according to any one of claims 1 to 3.   The said representative value determination part calculates the average value of the distance from the upper surface of the said table in the said projection part, The said average value is made into the said representative value of the said projection part, The any one of Claims 1-4 The inspection device described in 1.   The determination unit calculates the difference between the maximum value and the minimum value of the representative values in a plurality of protrusions as flatness, and performs the determination by comparing the flatness with a preset reference value. The inspection apparatus according to any one of claims 1 to 5.   The inspection according to claim 1, wherein the determination unit further calculates a distance between the plurality of protrusions from the surface shape data, and further determines whether the distance satisfies a preset criterion. apparatus.   The determination unit according to any one of claims 1 to 7, wherein the determination unit further determines whether a shape of a main body that supports the plurality of protrusions represented by the surface shape data satisfies a preset criterion. The inspection device described.   The determination unit further calculates an inclination angle of the plurality of protrusions with respect to the upper surface of the table from the surface shape data, and further determines whether the inclination angle satisfies a preset criterion. The inspection apparatus according to any one of 1 to 8. An inspection method for inspecting an inspection object having a plurality of protrusions arranged in at least one direction,
A light irradiation step of irradiating the inspection object placed on the upper surface of the transparent table with a light pattern in which the intensity of light periodically changes from the lower surface of the table;
An imaging step of photographing the inspection object irradiated with the light pattern from the lower surface of the table;
An image processing step in which a computer processes the image of the inspection object imaged in the imaging step to generate surface shape data representing a three-dimensional shape of the surface of the inspection object;
A representative value determining step in which the computer determines a representative value of a value indicating a position with respect to the upper surface of the table in each of the plurality of protrusions represented by the surface shape data generated in the image processing step;
And a determination step of determining whether a distribution of the representative values in the plurality of protrusions satisfies a preset criterion. An inspection program for inspecting an inspection object having a plurality of protrusions arranged in at least one direction,
A transparent table for placing the inspection object;
A light irradiation unit that irradiates a light pattern in which the intensity of light periodically changes from the lower surface of the table to the inspection object placed on the upper surface of the table;
An imaging unit that photographs the inspection object irradiated with the light pattern from a lower surface of the table;
The surface shape data from a measuring device comprising: an image processing unit that processes an image of the inspection object imaged by the imaging unit and generates surface shape data representing a three-dimensional shape of the surface of the inspection object Input processing that accepts
In each of the plurality of protrusions represented by the surface shape data, representative value determination processing for determining a representative value indicating a position of the protrusion with respect to the upper surface of the table;
An inspection program that causes a computer to execute a determination process for determining whether a distribution of the representative values in the plurality of protrusions satisfies a preset criterion.

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