JP2016045019A - Teaching device for substrate inspection device, and teaching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a teaching device by which an image-capturing condition for inspecting various types of objects to be inspected that are on a substrate is set easily for a substrate inspection device.SOLUTION: A teaching device 2 has: an image acquisition unit 110 for acquiring a plurality of images corresponding to each of a plurality of image-capturing conditions which are obtained from the process of capturing the images of a plurality of objects 150, 151 to be inspected that are on a substrate 15, the process being executed by a substrate inspection device 1 while switching the image-capturing conditions that are conditions for pattern light PL to be projected; and an image-capturing condition setting unit for selecting, on the basis of the plurality of images acquired by the image acquisition unit, an optimum image-capturing condition for each object to be inspected from among the plurality of image-capturing conditions, and setting the selected image-capturing condition for each object to be inspected to the substrate inspection device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a board inspection apparatus for inspecting a printed circuit board, and more particularly to a technique for teaching operation during inspection in a board inspection apparatus.

  In a surface mounting line for printed circuit boards, board inspection apparatuses for inspecting the state of components and solder on the board are widely used. In the board inspection apparatus, various indicators related to the shape of the component and the solder are measured from an image obtained by photographing the board, and the float of the component, the solder bonding state, and the like are inspected based on the measured values. At this time, since it is necessary to inspect the three-dimensional shape of the object using an image which is two-dimensional information, an imaging system using special illumination is often used.

  For example, a technique called a phase shift method is known. The phase shift method is one of methods for obtaining height information of an object by projecting striped pattern light onto the surface of the object and analyzing the distortion (change in phase) of the pattern. In the method using this kind of special illumination, there is a problem that the measurement accuracy is likely to be lowered unless the imaging condition (illumination condition) is set appropriately. However, since various types of electronic components having different sizes (heights), colors, and materials are generally mounted on the substrate, all such various electronic components can be measured with high accuracy. Thus, it is extremely difficult to adjust the imaging conditions.

  In Patent Document 1, when measuring cream solder printed on a substrate using a phase shift method, the average luminance of the background region deviates from the target luminance in order to separate the solder region and the background region. In such a case, a method of re-imaging after correcting the luminance of the illumination light has been proposed. Although this method has an advantage that an appropriate amount of light is selected in accordance with an actual inspection substrate, adaptively correcting the luminance during the inspection has a disadvantage that it causes an increase in processing load. In particular, when there are a wide variety of parts on the substrate, such as post-mount inspection and post-reflow inspection, the processing time becomes enormous, which is not realistic.

JP 2006-3000539 A (Patent No. 48274431)

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the technique for test | inspecting the various kinds of test target object on a board | substrate accurately.

  A further object of the present invention is to provide a technique for easily setting an imaging condition for accurately inspecting various types of inspection objects on a substrate with respect to the substrate inspection apparatus.

In order to achieve the above object, the present invention employs the following configuration. That is, the teaching device according to the present invention operates when imaging a substrate with respect to a substrate inspection device having a function of measuring the height of an inspection object on the substrate using an image captured by projecting pattern light. Obtained by performing a process of imaging a plurality of inspection objects on a substrate by the substrate inspection apparatus a plurality of times while switching an imaging condition that is a condition of a pattern light to be projected. An image acquisition unit that acquires a plurality of images corresponding to each of a plurality of imaging conditions, and an optimum of the plurality of imaging conditions for each inspection object based on the plurality of images acquired by the image acquisition unit An imaging condition setting unit that selects an imaging condition and sets an imaging condition for each selected inspection object in the substrate inspection apparatus. We are a teaching device location.

  According to such a configuration, an optimum imaging condition for each inspection object on the substrate can be set in advance by the teaching device. Then, when inspecting with the substrate inspection apparatus, the pattern light is projected and imaged under the optimal imaging conditions for each inspection object, thereby inspecting according to the characteristics (size, color, reflection characteristics, etc.) for each inspection object. Since a working image can be obtained, it is possible to accurately inspect various types of inspection objects. In addition, since the imaging condition for each inspection object is automatically determined using a plurality of images captured by the substrate inspection apparatus, teaching can be performed extremely simply and efficiently. The substrate used for capturing a plurality of images may be a substrate manufactured for teaching or a substrate manufactured on an actual surface mounting line.

  It is preferable that the plurality of imaging conditions include a plurality of conditions in which height measurement ranges of the substrate inspection apparatus are different from each other. This is because inspection objects of various sizes (heights) may exist on the substrate. The plurality of conditions having different measurement ranges are, for example, a plurality of conditions having different pattern light patterns to be projected.

  At this time, the imaging condition setting unit calculates the height of the inspection object using an image corresponding to the imaging condition having the widest measurement range among the plurality of images, and the inspection is performed from the plurality of imaging conditions. It is preferable to select an imaging condition having a measurement range suitable for the height of the object. By adopting such a procedure, it is possible to set an appropriate measurement range for inspection objects of various sizes from short to tall, and high-precision height measurement is possible regardless of size. Become.

  The plurality of imaging conditions preferably include a plurality of conditions in which the amount of pattern light to be projected is different from each other. This is because inspection objects having various colors and reflection characteristics may exist on the substrate.

  The plurality of images include a patternless image captured in a state where light having a uniform luminance is projected, and the imaging condition setting unit is configured to select the plurality of images based on the patternless image of the inspection target at each light amount. It is preferable to select an imaging condition with a light amount suitable for the inspection object from the imaging conditions. If an image without a pattern is used, the overall luminance of the inspection object can be grasped with only one image, and the occurrence of overexposure or underexposure can be easily detected, so that the light quantity selection processing logic can be simplified.

  Based on the imaging condition for each inspection object selected by the imaging condition setting unit, the imaging procedure setting unit further sets an imaging procedure setting unit that sets up a plurality of imaging areas to be imaged when inspecting the substrate. It is preferable to set the position of the imaging area so that a plurality of inspection objects under the same imaging condition fall within the same imaging area. By making a plurality of inspection objects under the same imaging conditions fall within the same imaging area, the number of imaging areas, that is, the number of imaging operations during inspection can be reduced, so that the inspection time can be shortened.

  The imaging condition setting unit is configured to capture the two imaging areas when the imaging conditions of the two imaging areas are similar and all of the plurality of inspection objects included in the two imaging areas fit in one imaging area. It is preferable to set a single imaging area by integrating the areas. By performing such integration processing, the number of imaging areas, that is, the number of times of imaging at the time of inspection can be further reduced, so that the inspection time can be further shortened.

The present invention can be understood as a teaching device that includes at least a part of the above means or functions. Moreover, this invention can also be grasped | ascertained as a board | substrate inspection system which has the said teaching apparatus and a board | substrate inspection apparatus. The present invention can also be understood as a teaching method for a substrate inspection apparatus, a computer program for causing a computer to execute each step of the method, or a computer-readable storage medium that stores the program in a non-temporary manner. . Each of the above configurations and processes can be combined with each other as long as no technical contradiction occurs.

  According to the present invention, imaging conditions for accurately inspecting various types of inspection objects on a substrate can be easily set for the substrate inspection apparatus.

The schematic diagram which shows the hardware constitutions of a board | substrate inspection system. The block diagram which shows the function structure of a board | substrate inspection system. The flowchart which shows the procedure of construction | assembly of teaching image DB. An example of an image data set acquired from a sample substrate. The flowchart which shows the flow of the production | generation process of a test | inspection program. The flowchart (1) which shows the flow of a light quantity selection process. The flowchart (2) which shows the flow of a light quantity selection process. The flowchart which shows the flow of a pattern selection process. The flowchart which shows the flow of an imaging procedure determination process. The figure which shows the example of a setting of an imaging procedure typically. The flowchart which shows the flow of an inspection process. The example of the phase image imaged by projecting pattern light.

  Preferred embodiments for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified.

(Hardware configuration of board inspection system)
With reference to FIG. 1, the overall configuration of a substrate inspection system according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing a hardware configuration of a substrate inspection system. The board inspection system includes a board inspection apparatus 1 that inspects the state of components and solder on a printed board using an image captured by a camera, a teaching apparatus 2 that creates an inspection program used by the board inspection apparatus 1 during inspection, And a storage device 3. The substrate inspection apparatus 1 is preferably used for substrate appearance inspection (for example, component float inspection after reflow) in a surface mounting line.

  The substrate inspection apparatus 1 includes a stage 10, a measurement unit 11, a control device 12, an information processing device 13, and a display device 14 as main components. The measurement unit 11 includes a camera (image sensor) 110, an illumination device 111, and a projection device (projector) 112.

  The stage 10 is a mechanism for holding the substrate 15 and aligning the component 150 and the solder 151 to be inspected with the field of view of the camera 110. As shown in FIG. 1, when the X axis and the Y axis are taken in parallel to the stage 10 and the Z axis is taken perpendicular to the stage 10, the stage 10 can translate at least two axes in the X direction and the Y direction. The camera 110 is arranged so that the optical axis is parallel to the Z axis, and images the substrate 15 on the stage 10 from above. Image data captured by the camera 110 is taken into the information processing apparatus 13.

  The illumination device 111 (111R, 111G, 111B) is an illumination unit that irradiates the substrate 15 with illumination light (red light RL, green light GL, blue light BL) of different colors (wavelengths). FIG. 1 schematically shows an XZ cross section of the illuminating device 111. Actually, the illuminating device 111 has an annular shape so that light of the same color can be illuminated from all directions (all directions around the Z axis). Or it has a dome shape. The projection device 112 is a pattern projection unit that projects pattern light PL having a predetermined pattern onto the substrate 15. Projection device 112 projects pattern light PL through an opening provided in the middle of illumination device 111. The number of the projection devices 112 may be one, but a plurality of projection devices 112 may be provided in order to eliminate the blind spot of the pattern light PL. In the present embodiment, the two projectors 112 are arranged in different directions (diagonal positions). As the projection device 112, a DLP (Digital Light Processing) projector using a digital mirror device can be preferably used. The illumination device 111 and the projection device 112 are both illumination systems used when photographing the substrate 15 with the camera 110, but the illumination device 111 is illumination used for shape measurement by the color highlight illumination method, and the projection device 112. Is illumination used for shape measurement by the phase shift method.

  The control device 12 is a control unit that controls the operation of the substrate inspection apparatus 1. The movement control of the stage 10, the lighting control of the illumination device 111, the lighting control of the projection device 112, the pattern / light quantity change, and the imaging control of the camera 110. It is responsible for.

  The information processing apparatus 13 acquires various measurement values related to the component 150 and the solder 151 using the image data captured from the camera 110, and the state of solder bonding to the electrode of the component 150 and the land (pad) on the board It is a device having a function of inspecting. The display device 14 is a device that displays measurement values and inspection results obtained by the information processing device 13. The storage device 3 is a database in which an inspection program used in the substrate inspection apparatus 1 and data (images, measurement results, inspection results, etc.) obtained by the substrate inspection apparatus 1 are stored. The inspection program includes information on the inspection object existing on the substrate (product number, position, size, etc.), imaging conditions (setting values of the illumination device 111 and the projection device 112, etc.), the imaging area, the imaging order, and the inspection object. Each inspection item, determination reference value (threshold or value range for determining good / bad), and the like are defined. Prior to the inspection, the inspection program is created by the teaching device 2 and registered in the storage device 3 (this operation is called teaching).

  The information processing device 13 can be configured by, for example, a general-purpose computer having a CPU (Central Processing Unit), a memory, an auxiliary storage device (such as a hard disk drive), and an input device (such as a keyboard, mouse, and touch panel). The teaching device 2 can also be constituted by a general-purpose computer having a CPU, a memory, an auxiliary storage device, and an input device, for example. In FIG. 1, the control device 12, the information processing device 13, the display device 14, the teaching device 2, and the storage device 3 are shown as separate blocks, but these may be configured as separate devices, or simply. You may comprise with one apparatus.

(Phase shift method and its problems)
In the board inspection apparatus 1 of this embodiment, a phase shift method is used to measure the three-dimensional shape of an inspection object such as a component.

The phase shift method is one of methods for measuring three-dimensional information (height information) on the object surface by analyzing pattern distortion when pattern light is projected onto the object surface. Specifically, using the projection device 112, shooting is performed with the camera 110 in a state where a predetermined pattern (for example, a striped pattern whose luminance changes in a sine wave shape) is projected onto the substrate. Then, as shown in FIG. 11, pattern distortion corresponding to the unevenness appears on the object surface. By repeating this process a plurality of times (for example, four times) while changing the phase of the luminance change of the pattern light, a plurality of images having different luminance characteristics (hereinafter referred to as phase images) are obtained as shown in FIG. It is done. Since the brightness (luminance) of the same pixel in each image should change at the same cycle as the change in the striped pattern, the phase of each pixel can be obtained by applying a sine wave to the change in brightness of each pixel. I understand. The distance (height) from the reference position can be calculated by obtaining a phase difference with respect to the phase of a predetermined reference position (table surface, substrate surface, etc.).

  By the way, in the phase shift method, in principle, it is impossible to measure a height at which the phase change exceeds 2π (because phase folding occurs). Therefore, the measurement range of the phase shift method (the range of the measurable height) depends on the period size of the striped pattern. Therefore, in the conventional substrate inspection apparatus, it is general to set a required measurement range based on the assumed maximum height and determine the period of the striped pattern so as to ensure the required measurement range. However, the measurement range and the distance resolution are in a trade-off relationship, and there is a problem that the measurement accuracy decreases as the measurement range is expanded. Recently, there are parts with a thickness of about 100 um due to downsizing and thinning of parts, but there are also parts with a height exceeding 1 inch, and these various parts types can be combined in a single measurement range. It is difficult to measure accurately.

  Further, in a conventional substrate inspection apparatus, pattern light is usually projected with a light amount setting that matches a general substrate or component. However, studies by the present inventors have revealed that it is not appropriate to image all types of parts with the same amount of light. For example, in the case of a highly specular part, the gradation information of the striped pattern may be lost due to luminance saturation (saturation). Conversely, in the case of a black part or the like, the striped pattern becomes unclear due to insufficient light quantity. Because there are cases. In either case, it is difficult to accurately detect the phase of the striped pattern, leading to a decrease in measurement accuracy.

  In view of the problems as described above, in the substrate inspection apparatus 1 of the present embodiment, various types on the substrate are optimized by optimizing the imaging conditions (for example, the period of the pattern light to be projected and the amount of light) for each inspection object. All of the inspection objects can be accurately measured.

  Further, when such a function is mounted on the board inspection apparatus 1, the following new problem arises from a practical viewpoint. The first problem is related to teaching of the substrate inspection apparatus 1. If it is necessary to manually teach the optimal imaging conditions for each inspection object, the operator changes the setting of the projection device, images the inspection object, and confirms the obtained image and the measured height on the screen. However, it is necessary to repeat the work of correcting the inspection program, which takes a lot of time. In addition, there is also a problem that an operator needs knowledge about the principle of the phase shift method in order to determine whether the imaging conditions are optimal. Therefore, it is desired to provide a teaching method capable of automatically (or only by extremely simple work) setting an optimum imaging condition for each inspection object. The second problem is related to the inspection time. When the imaging condition is changed for each inspection object, the number of times of imaging increases accordingly, so that it is inevitable that the inspection time becomes longer than the conventional imaging method under a single condition. Therefore, it is practically extremely important to shorten the inspection time as much as possible by improving the efficiency of the process by devising the imaging procedure.

  Hereinafter, specific examples of the teaching process of the inspection program by the teaching device 2 and the inspection processing by the substrate inspection device 1 will be described with respect to the shape measurement using the phase shift method. In the substrate inspection system of this embodiment, measurement and inspection using the color highlight illumination method is also performed, but a description thereof is omitted because a known method can be used.

(Functional configuration of board inspection system)
FIG. 2 is a block diagram showing a functional configuration of the board inspection system. The board inspection system functions as an imaging control unit 130, an image capture unit 131, a phase information analysis unit 132, an image data set creation unit 133, an inspection unit 134, an inspection result output unit 135, and a teaching image DB (database). 30, inspection program DB 31, inspection result DB 32, teaching image acquisition unit 20, inspection object setting unit 21, imaging condition setting unit 22, feature setting unit 23, imaging procedure setting unit 24, and the like.

  The imaging control unit 130 has a function of controlling lighting / extinction of the projection device 112 and imaging conditions (pattern presence / absence, pattern period / phase, light amount, etc.) via the control device 12. The image capturing unit 131 has a function of capturing image data from the camera 110. The phase information analysis unit 132 has a function of analyzing a plurality of phase images to obtain the height of each pixel. The image data set creation unit 133 has a function of creating an image data set for each imaging condition and registering it in the teaching image DB 30. The inspection unit 134 has a function of inspecting an inspection object according to an inspection program stored in the inspection program DB 31. The inspection result output unit 135 has a function of outputting the measurement values and inspection results obtained by the inspection unit 134 to the screen.

  The teaching image acquisition unit 20 has a function of reading an image data set for each imaging condition used for teaching from the teaching image DB 30. The inspection object setting unit 21 has a function of setting the position and size of the inspection object on the substrate. The imaging condition setting unit 22 has a function of selecting and setting an optimal imaging condition for each inspection object. The feature setting unit 23 has a function of extracting and setting features (height, shape, color, etc.) of the inspection object. The imaging procedure setting unit 24 has a function of setting the imaging procedure of the board at the time of inspection.

  In the present embodiment, functional units 130 to 135 are provided by the information processing device 13, functional units 30 to 32 are provided by the storage device 3, and functional units 20 to 24 are provided by the teaching device 2. The However, since all of these functional units are realized by software by executing a necessary program by the CPU, the logical configuration and execution subject of each function are not limited to the configuration of FIG. Alternatively, all or some of the functions can be configured by a circuit such as an ASIC or FPGA.

(Teaching)
Teaching of the present embodiment is roughly divided into three steps: (1) construction of a teaching image DB, (2) determination of optimum imaging conditions for each inspection object, and (3) determination of imaging procedure of the board. Become. Hereinafter, the specific processing content of each process is demonstrated.

(1) Construction of teaching image DB First, the substrate inspection apparatus 1 captures a teaching sample substrate under various imaging conditions, and performs processing for acquiring an image data set for each imaging condition. The necessary data can be obtained at the first stage and collected into a database, so that subsequent teaching can be performed efficiently.

3 and 4 show the procedure for constructing the teaching image DB.
The operator sets the teaching sample substrate 40 on the stage 10 of the substrate inspection apparatus 1 (step S300), and inputs an instruction to start teaching imaging to the substrate inspection apparatus 1 (information processing apparatus 13) (step S300). S301). As the sample substrate 40, a non-defective substrate on which all components to be inspected are mounted in a correct state may be used. This is for teaching the correct height and position of each inspection object.

  In step S <b> 302, the imaging control unit 130 controls the stage 10 and moves the imaging area 41 on the sample substrate 40 within the field of view of the camera 110. Note that each time the processing of step S302 is executed, the imaging control unit 130 sequentially switches the imaging areas as indicated by the broken-line arrows in FIG. 4 so that the entire substrate can be imaged without omission.

In step S <b> 303, the imaging control unit 130 sets a pattern to be projected on the projection device 112. In the present embodiment, every time the process of step S303 is executed, the following three types of patterns are sequentially switched.
-Pattern A: Period: Large, Measurement range: 30 mm
Pattern B: Period: Medium, Measurement range: 15 mm
Pattern C: Period: small, measurement range: 7 mm
The pattern A is a pattern suitable for a tall part, and the pattern C is a pattern suitable for a thin part.

In step S <b> 304, the imaging control unit 130 sets the light amount for the projection device 112. In the present embodiment, every time the process of step S304 is executed, the following five types of light quantities are sequentially switched.
・ Light quantity 1… Bright light ・ Light quantity 2 ・ Slightly bright light ・ Light quantity 3 ... Standard light quantity ・ Light quantity 4 ... Slightly dark light ・ Light quantity 5 ... Dark light Light quantities 1 and 2 are suitable for black parts. The light amount 4 and the light amount 5 are light amounts suitable for parts having specularity or white parts.

  In step S305, the imaging control unit 130 turns on the projection device 112 with the pattern set in step S303 and the light amount set in step S304, and the camera 110 performs imaging. The captured image data is captured by the information processing device 13 by the image capturing unit 131. In the present embodiment, in step S305, four imaging operations are performed while changing the phase of the pattern by 90 degrees, and four phase images are acquired. Reference numeral 42 in FIG. 4 indicates four phase images obtained from the imaging area 41.

  In step S306, the phase information analysis unit 132 calculates the height of each pixel by analyzing the phase of the luminance change of each pixel from the four phase images obtained in step S305. The calculated height information is stored in the form of image data (referred to as height data) in which the height (Z position) is expressed by a pixel value. Reference numeral 43 in FIG. 4 is an example of the height data of the imaging area 41, and the higher portion is indicated by brighter (closer to white) pixels.

In step S307, the phase information analysis unit 132 calculates the reliability of the phase information of each pixel. In this embodiment, for each pixel, the amount of change in luminance (difference between minimum luminance and maximum luminance) between the four phase images is calculated,
・ Pixels whose luminance change is equal to or greater than the threshold → Reliability = 1 (high)
・ Pixels whose luminance change is smaller than the threshold → Reliability = 0 (low)
Thus, the reliability of the phase information is determined. This is because the amount of change in luminance increases as the pattern light becomes brighter. In the present embodiment, the reliability is obtained as a binary value of 1 (high) / 0 (low). For example, by normalizing the amount of change in luminance of each pixel with the maximum value of the amount of change, 1. The reliability may be calculated with a continuous value of 0 (high) to 0.0 (low). As with the height information, the reliability information is also stored in the form of image data called a reliability map. 44 of FIG. 4 is an example of the reliability map of the imaging area 41, and a portion with low reliability of the phase information is indicated by a bright (white) pixel.

In step S <b> 308, the imaging control unit 130 projects illumination with no pattern (illumination with uniform luminance) from the projection device 112 with the light amount set in step S <b> 304, and the camera 110 performs imaging. The imaged patternless image is captured by the information processing device 13 by the image capturing unit 131. Reference numeral 45 in FIG. 4 shows an example of an image without a pattern. This patternless image is used for selecting a light amount condition and setting an inspection window, which will be described later.

  In step S309, the image data set creation unit 133 creates an image data set 46 including “four phase images 42”, “height data 43”, “reliability map 44”, and “patternless image 45”. The image data set 46 is created and registered in the teaching image DB 30 in association with the imaging conditions (pattern, light amount).

  By executing the above processing for all combinations of the patterns A to C and the light amounts 1 to 5, 15 sets of image data corresponding to 15 types of imaging conditions are prepared in the teaching image DB 30. When the sample substrate 40 is imaged by dividing it into a plurality of imaging areas 41, the data of the plurality of imaging areas 41 is included in the image data set of each group (each imaging condition). After the completion of teaching imaging, the operator takes out the sample substrate 40 from the substrate inspection apparatus 1 and the construction of the teaching image DB is completed.

  Note that the above-described image area classification, pattern type / number, light quantity type / number, and the like are merely examples. Variations in the pattern and light quantity can be set as appropriate according to the need for subsequent teaching and inspection. Further, the division of the imaging area, the pattern, and the variation of the light amount may be automatically set by the substrate inspection apparatus 1 or the teaching apparatus 2 based on CAD information or the like, or may be manually set by an operator.

(2) Determination of Optimal Imaging Conditions for Each Inspection Object Next, an optimal imaging condition determination process performed by the teaching device 2 will be described with reference to the flowcharts of FIGS. FIG. 5 is a flowchart showing the flow of inspection program generation processing, FIGS. 6A and 6B are flowcharts showing the flow of light quantity selection processing, and FIG. 7 is a flowchart showing the flow of pattern selection processing.

  When the operator instructs the teaching apparatus 2 to create a new inspection program, the teaching image acquisition unit 20 reads the image data set of the corresponding board from the teaching image DB 30 (step S500). In the present embodiment, as described above, 15 image data sets corresponding to 15 imaging conditions are read.

  Next, the inspection object setting unit 21 sets an inspection window for each of the plurality of inspection objects on the substrate (step S501). The inspection window is information for specifying the position and size of the inspection object, and is set by, for example, a circumscribed rectangle of the inspection object. The inspection window may be set automatically by the inspection object setting unit 21 based on CAD information or may be manually set by an operator. In the case of manual setting, the operation is simple if an image without a pattern in the image data set is displayed on the screen and the region of the inspection window can be designated on the image using a mouse or the like. A typical inspection object is a part, but an object other than a part (for example, a part of a part such as an electrode, land, solder, wiring, or the like) may be set as the inspection object.

  Thereafter, the processes in steps S502 to S505 are individually performed on all inspection objects for which the inspection window is set. Hereinafter, the inspection object which is the object of processing is referred to as “target object”.

(2-1) Selection of light quantity condition In step S502, the imaging condition setting unit 22 selects a light quantity condition optimal for the target object. Details of the processing in step S502 are shown in FIGS. 6A and 6B.

  The imaging condition setting unit 22 reads out an image without a pattern from the image data set of the standard light quantity (light quantity 3) (in this embodiment, as the image data set of light quantity 3, the light quantity 3 + pattern A, the light quantity 3 + pattern B, and the light quantity 3 + pattern. There are three types of image data sets of C, but the images without pattern are the same, so any one of the image data sets may be used.) Within the inspection window of the target object from the images without pattern Are cut out (step S600). In the following description, the image cut out in this way is expressed as “an image without a pattern of the target object with the light amount xx” or simply “an image with the light amount xx”.

  The imaging condition setting unit 22 determines whether or not a whiteout region exists in the patternless image of the target object with the standard light amount (light amount 3) obtained in step S600 (step S601). For example, when the pixel value takes a value of 0 (black) to 255 (white), if the ratio of “the number of pixels with a pixel value of 250 or more” to the “total number of pixels of the image” is equal to or greater than a threshold, What is necessary is just to determine with it. If there is a whiteout area (step S601; YES), the process proceeds to step S602. If there is no whiteout area (step S601; NO), the process proceeds to step S606.

  In step S602, the imaging condition setting unit 22 acquires a pattern-less image of the target object with a light amount darker than the standard light amount (light amount 4 and light amount 5 in this embodiment). Then, the imaging condition setting unit 22 checks whether there is a whiteout region in the image with the respective light amounts 4 and 5, and when a light amount in which no whiteout region is generated is found (step S603; YES), The light quantity is selected as one of the light quantity conditions of the target object (step S604). In step S603, when a plurality of light quantities that do not generate a whiteout area are found, the brightest light quantity is selected from them (for example, if there is no whiteout area in any of the light quantities 4, 5) Choose the method.) On the other hand, in step S603, when there is no light amount that does not have a whiteout region (when whiteout occurs even if shooting is performed with any light amount), the darkest light amount among all the light amounts (this embodiment) Then, the light quantity 5) is selected as one of the light quantity conditions of the target object (step S605).

  In step S606, the imaging condition setting unit 22 again uses the pattern-less image of the target object with the standard light amount (light amount 3), and determines whether or not a blackout region exists in the image. For example, when the pixel value takes a value from 0 (black) to 255 (white), if the ratio of “the number of pixels having a pixel value of 10 or less” to the “total number of pixels in the image” is equal to or greater than a threshold, What is necessary is just to determine with it. When there is a blackout area (step S606; YES), the process proceeds to step S607, and when there is no blackout area (step S606; NO), the process proceeds to step S611.

  In step S607, the imaging condition setting unit 22 acquires a pattern-less image of the target object with a light amount brighter than the standard light amount (in this embodiment, light amount 1 and light amount 2). Then, the imaging condition setting unit 22 checks whether there is a blacked-out area in the image with the respective light amounts 1 and 2, and when a light quantity that does not generate the blacked-out area is found (step S608; YES), The light amount is selected as one of the light amount conditions of the target object (step S609). In step S608, when a plurality of light amounts that do not generate a blacked-out area are found, the darkest light quantity may be selected (for example, if there is no blacked-out area in any of the light quantities 1 and 2) Choose the method.) On the other hand, in step S608, when there is no light amount without the blacked-out area (when blacked-out occurs regardless of the amount of light taken), the brightest light amount among all the light amounts (this embodiment) Then, the light quantity 1) is selected as one of the light quantity conditions of the target object (step S610).

In step S611, the imaging condition setting unit 22 reads the reliability map from the image data set of the standard light quantity (light quantity 3), and each pixel of the image of the target object with the standard light quantity (however, the whiteout area and the blackout area) (Excluding the pixel of.) Is obtained. In the following description, the reliability map obtained in this way is expressed as “reliability map of the target object with the light quantity xx” or simply “reliability map with the light quantity xx”. By the way, in the present embodiment, there are three types of image data sets of light amount 3 + pattern A, light amount 3 + pattern B, and light amount 3 + pattern C as the light amount 3 image data set, but the reliability of any one of the image data sets Only a map may be used, or a reliability map of a plurality of image data sets may be used.

  In step S612, the imaging condition setting unit 22 evaluates the reliability of the phase information with the light amount based on the reliability map of the target object with the standard light amount obtained in step S611. For example, the average value of the reliability in the reliability map of the target object is calculated, and when the average value is larger than a predetermined threshold, “reliability is high”, otherwise “reliability is low”, Can be determined. When the reliability is high (step S612; YES), the standard light amount (light amount 3) is selected as one of the light amount conditions of the target object (step S613). On the other hand, when the reliability is low (step S612; NO), the process proceeds to step S614.

  In step S614, the imaging condition setting unit 22 acquires a reliability map of the target object with a light amount brighter than the standard light amount (in this embodiment, light amount 1 and light amount 2). Then, the imaging condition setting unit 22 evaluates the reliability of the phase information at each of the light amounts 1 and 2 and checks whether there is a light amount with high reliability (step S615). If a light amount with high reliability is found (step S615; YES), the light amount is selected as one of the light amount conditions of the target object (step S616). In step S615, when a plurality of light amounts with high reliability are found, the darkest light amount may be selected (for example, if both the light amounts 1 and 2 are high in reliability, the light amount 2 is selected). .) On the other hand, in step S615, when there is no light with high reliability (when the reliability of phase information is low regardless of the amount of light taken), pay attention to the light with the highest reliability among all the light. One of the light quantity conditions for the object is selected (step S617).

  In step S618, the imaging condition setting unit 22 registers the light amount condition selected in steps S604, S605, S609, S610, S613, S616, and S617 as the optimum light amount condition of the target object in the inspection program. As can be seen from the flowcharts of FIGS. 6A and 6B, the present embodiment also allows a case where a plurality of light quantity conditions are selected for one target object. For example, in a component in which a black portion and a portion having specularity are mixed, height information of the entire component may not be accurately measured under a single light amount condition. In that case, a plurality of light quantity conditions may be set, imaging and measurement may be performed under each light quantity condition at the time of inspection, and a highly reliable measurement value (height information) may be synthesized.

(2-2) Selection of Pattern Condition Returning to the flow of FIG. 5, in step S503, the imaging condition setting unit 22 selects a pattern condition optimal for the target object. Details of the processing in step S503 are shown in FIG.

  The imaging condition setting unit 22 acquires height data from the image data set corresponding to the pattern having the widest measurement range among the image data sets corresponding to the light amount condition selected in step S502 (step S700). For example, if “light quantity 3” is selected in step S502, the height data of the image data set of light quantity 3 + pattern A is used. Here, the reason why the height data of the pattern A having the widest measurement range is used is that the height of the target object is unknown at this stage. If a plurality of light amount conditions are selected in step S502, for example, if “light amount 2” and “light amount 3” are selected, the image data of light amount 2 + pattern A and light amount 3 + pattern A, respectively. It is advisable to obtain the height data of the set and use the height data obtained by combining or averaging them.

In step S701, the imaging condition setting unit 22 performs reference plane correction on the height data acquired in step S700. Specifically, the height of each pixel in the height data is corrected so that the height of the reference surface (for example, the surface of the substrate) becomes zero. Then, the imaging condition setting unit 22 calculates the height of the target object (the height from the reference plane) based on the corrected height data (step S702). For example, an average value of the heights of all the pixels in the part area within the inspection window of the target object may be calculated.

  Next, the imaging condition setting unit 22 selects a pattern condition having a measurement range most suitable for the height of the object of interest from among a plurality of pattern conditions (patterns A to C), and registers the pattern condition in the inspection program (step) S703). For example, a pattern having the narrowest measurement range may be selected as the optimum pattern condition among patterns in which the height of the target object is within the measurement range.

  Through the above processing, the optimum imaging conditions (light quantity condition and pattern condition) of the target object are automatically set.

  Thereafter, returning to the flow of FIG. 5, the feature setting unit 23 extracts and learns various features of the target object. Specifically, in step S504, the feature setting unit 23 uses the height data of the image data set corresponding to the imaging conditions set in steps S502 and S503, and uses the height of the target object (from the reference plane). Calculate the height. Since this process is the same as that described in steps S701 and S702, a description thereof will be omitted. The reason why the height of the target object is calculated again in step S504 is that a more accurate value of the height of the target object is obtained by performing recalculation using the height data corresponding to the optimum measurement range. Because it can. The feature setting unit 23 registers the height of the target object obtained in step S504 in the inspection program as the correct answer height of the target object. In step S505, the feature setting unit 23 extracts various parameters related to the color and shape of the target object using a pattern-less image of the target object, and the parameters and the determination reference value obtained from the parameters. Etc. are registered in the inspection program.

  By performing the processing of steps S502 to S505 described above individually for all inspection objects on the substrate, it is possible to automatically set optimal imaging conditions, determination reference values, and the like for each inspection object. . When the setting of all the inspection objects is completed, the process proceeds to an imaging procedure determination process in step S506.

(3) Determination of Imaging Procedure for Substrate In step S506, the imaging procedure setting unit 24 determines the position of each imaging area to be imaged at the time of inspection based on the imaging conditions for each inspection object set in steps S502 and S503. An imaging condition and an imaging order (moving route of the imaging area) are set. Details of the processing in step S506 are shown in FIG. FIG. 9 is a diagram schematically illustrating an example of setting an imaging procedure.

  First, the imaging procedure setting unit 24 sets an imaging area 92 for capturing an image for alignment with respect to the fiducial mark on the substrate (step S800). FIG. 9A shows a state in which imaging areas 92a and 92b are set for two fiducial marks 91a and 91b at diagonal positions of the substrate 90, respectively. The size of the imaging area is set to be the same as or smaller than the field of view of the camera 110 of the substrate inspection apparatus 1.

Thereafter, the imaging procedure setting unit 24 extracts the inspection object in which the same imaging condition is set for each imaging condition (combination of the pattern and the light amount) (step S801), and the extracted inspection object is imaged as much as possible. The imaging area is set so as to enter the area (in other words, to cover all inspection objects with as few imaging areas as possible) (step S802). FIG. 9B shows a state in which one imaging area 94 is set so as to include two parts 93a and 93b in which the imaging condition “pattern B + light quantity 4” is set. FIG. 9C shows a state where four imaging areas 96a to 96d are set for each of the four components 95a to 95d for which the imaging condition of “pattern B + light quantity 3” is set. Note that the problem of how to divide a plurality of extracted inspection objects may be solved by a full search with the maximum size of the imaging area as a constraint, or a known area division algorithm may be applied. May be.

  After the imaging area setting process (steps S801 to S802) is executed for each of the 15 imaging conditions, the imaging procedure setting unit 24 performs the imaging area integration process (step S803). The imaging area integration process is a process for reducing the total number of imaging areas by integrating (replacing) imaging areas with different imaging conditions into one imaging area. The imaging conditions of the two imaging areas are similar (that is, the imaging conditions of one imaging area can be replaced by the imaging conditions of the other imaging area), and a plurality of inspection objects included in the two imaging areas When all of the objects fit in one imaging area, the two imaging areas can be integrated. For example, imaging areas that have the same pattern but differ in light amount by one step can be integrated. FIG. 9D shows an example in which the imaging area 94 of “pattern B + light quantity 4” and the imaging area 96d of “pattern B + light quantity 3” are integrated and replaced with an imaging area 97 including three parts 93a, 93b, and 95d. is there.

  Subsequently, the imaging procedure setting unit 24 determines the order (movement route) for imaging the imaging area so that the moving distance of the stage 10 is the shortest (step S804). The moving route may be determined by full search or a known shortest path problem algorithm may be applied.

  The imaging procedure setting unit 24 registers the position and imaging conditions of each imaging area and information on the imaging order (hereinafter referred to as imaging procedure information) in the inspection program (step S805). By optimizing the imaging procedure as described above, the number of imaging operations can be reduced as much as possible, and the number of stage movements and the total movement distance can also be reduced as much as possible, thereby shortening the inspection time. Become.

  Finally, returning to the flow of FIG. 5, the teaching device 2 stores the generated inspection program in the inspection program DB 31 and ends the processing (step S507). Thereby, teaching for the substrate inspection apparatus 1 is completed, and preparation for inspection processing is completed.

(Inspection process)
An example of inspection processing in the substrate inspection apparatus 1 will be described with reference to the flowchart of FIG.

  First, the imaging control unit 130 reads an inspection program used from the inspection program DB 31 (step S100). The imaging control unit 130 images the fiducial mark on the substrate according to the imaging procedure information in the inspection program, and aligns the substrate (step S101).

The imaging control unit 130 moves the first imaging area within the field of view of the camera 110 according to the imaging procedure information (step S102), and then switches to the imaging conditions (pattern and light amount) set in the imaging area (step S103). ). Then, the imaging control unit 130 turns on the projection device 112 with the pattern / light quantity set in step S103, and the camera 110 captures a plurality of phase images (step S104). The captured phase image is captured by the information processing device 13 by the image capturing unit 131. Then, the phase information analysis unit 132 analyzes the phase image and generates the height data of the imaging area (step S105), and the inspection unit 134 determines the height of the inspection object included in the imaging area according to the inspection program. (3D shape) is calculated and compared with the judgment reference value to inspect the quality of the inspection object (step S10).
6). The inspection result of the inspection unit 134 is displayed on the screen by the inspection result output unit 135 or stored in the inspection result DB 32 (step S107).

  When the processes in steps S102 to S107 described above are executed for all imaging areas, the inspection process ends. In the flowchart of FIG. 10, the imaging process (steps S102 to S104) and the information processing (steps S105 to S107) are described as serial processes. However, the imaging process and the information processing may be executed in parallel. .

(Advantages of the substrate inspection system of this embodiment)
According to the substrate inspection system of the present embodiment, the optimal imaging conditions for each inspection object on the substrate can be set in advance by the teaching device 2. At the time of inspection by the substrate inspection apparatus 1, the pattern light is projected and imaged under an optimal imaging condition for each inspection object, so that the characteristics (size, color, reflection characteristics, etc.) of each inspection object are met. Since an inspection image can be obtained, it is possible to accurately inspect various types of inspection objects. In addition, since the imaging condition for each inspection object is automatically determined using a plurality of images of the sample substrate previously captured by the substrate inspection apparatus 1, teaching can be performed extremely simply and efficiently.

  Further, since two conditions of a pattern (period) and a light amount can be set as imaging conditions, it is possible to cope with inspection objects of various sizes (heights), colors, and reflection characteristics. In particular, since an appropriate measurement range according to the height of the inspection object is set, high-precision height measurement is possible regardless of the size.

  Furthermore, since the imaging procedure is optimized based on the imaging conditions for each inspection object, the number of imaging areas, that is, the number of imaging operations during inspection can be reduced, and the inspection time can be shortened.

<Other embodiments>
The description of the above embodiment is merely illustrative of the present invention, and the present invention is not limited to the above specific form. The present invention can be variously modified within the scope of its technical idea.

  For example, although the phase shift method is used in the above embodiment, other methods may be used as long as the object height information can be obtained from the image projected with the pattern light. Examples of methods for obtaining height information by projecting striped or grid pattern light onto an object and analyzing the image of the pattern distortion include a fringe analysis method and a spatial coding method.

  Moreover, in the said embodiment, although two conditions, a pattern (period) and a light quantity, were set, you may set only one of conditions.

  Moreover, although the board | substrate inspection apparatus used for the inspection after reflow was illustrated in the said embodiment, this invention can also be applied with respect to the board | substrate inspection apparatus utilized at the other processes of a surface mounting line. Further, the substrate inspection apparatus of the above embodiment has a measurement function by the color highlight illumination method, but this function is not essential, and this substrate inspection apparatus has only a measurement function by pattern light such as a phase shift method. The invention can also be applied.

1: substrate inspection device, 2: teaching device, 3: storage device 10: stage, 11: measurement unit, 12: control device, 13: information processing device, 14: display device,
20: Teaching image acquisition unit, 21: Inspection object setting unit, 22: Imaging condition setting unit, 23: Feature setting unit, 24: Imaging procedure setting unit 30: Teaching image DB, 31: Inspection program DB, 32: Inspection result DB
110: camera, 111: illumination device, 111B: blue light source, 111G: green light source, 111R: red light source, 112: projection device 130: imaging control unit, 131: image capturing unit, 132: phase information analysis unit, 133: Image data set creation unit, 134: inspection unit, 135: inspection result output unit RL: red light, BL: blue light, GL: green light, PL: pattern light

Claims (11)

A teaching device that teaches an operation when imaging a substrate with respect to a substrate inspection device having a function of measuring the height of an inspection object on the substrate using an image captured by projecting pattern light,
Corresponding to each of the plurality of imaging conditions obtained by executing the process of imaging a plurality of inspection objects on the substrate by the substrate inspection apparatus a plurality of times while switching the imaging conditions that are the conditions of the pattern light to be projected. An image acquisition unit for acquiring a plurality of images to be performed;
Based on the plurality of images acquired by the image acquisition unit, an optimum imaging condition is selected from the plurality of imaging conditions for each inspection object, and the imaging condition for each selected inspection object is selected from the substrate inspection apparatus. An imaging condition setting unit to be set for
A teaching apparatus for a substrate inspection apparatus, comprising: 2. The teaching apparatus of a substrate inspection apparatus according to claim 1, wherein the plurality of imaging conditions include a plurality of conditions in which a height measurement range of the substrate inspection apparatus is different from each other. The teaching apparatus for a substrate inspection apparatus according to claim 2, wherein the plurality of conditions with different height measurement ranges of the substrate inspection apparatus are a plurality of conditions with different patterns of pattern light to be projected. The imaging condition setting unit calculates the height of the inspection object using an image corresponding to the imaging condition having the widest measurement range among the plurality of images, and the inspection object is calculated from the plurality of imaging conditions. 4. The teaching apparatus for a substrate inspection apparatus according to claim 2, wherein an imaging condition having a measurement range suitable for the height is selected. 5. The teaching device of a substrate inspection apparatus according to claim 1, wherein the plurality of imaging conditions include a plurality of conditions in which light amounts of pattern light to be projected are different from each other. The plurality of images include a patternless image captured in a state of projecting light of uniform brightness,
The imaging condition setting unit selects an imaging condition of a light amount suitable for the inspection object from the plurality of imaging conditions based on an image without a pattern of the inspection object at each light amount. Item 6. A teaching apparatus for a substrate inspection apparatus according to Item 5. Based on the imaging conditions for each inspection object selected by the imaging condition setting unit, the imaging procedure setting unit further sets an imaging area to be imaged when inspecting the substrate,
The imaging procedure setting unit sets the position of the imaging area so that a plurality of inspection objects having the same imaging condition fall within the same imaging area. Teaching apparatus for the substrate inspection apparatus described. The imaging condition setting unit is configured to capture the two imaging areas when the imaging conditions of the two imaging areas are similar and all of the plurality of inspection objects included in the two imaging areas fit in one imaging area. The teaching apparatus for a substrate inspection apparatus according to claim 7, wherein areas are integrated to set one imaging area. The teaching device according to any one of claims 1 to 8,
In accordance with the imaging conditions for each inspection object set by the teaching device, the substrate inspection apparatus that images the inspection object on the substrate and inspects the inspection object using the obtained image;
A board inspection system comprising: A teaching method for teaching an operation when imaging a substrate for a substrate inspection apparatus having a function of inspecting the height of an inspection object on the substrate using an image captured by projecting pattern light,
Computer
Corresponding to each of the plurality of imaging conditions obtained by executing the process of imaging a plurality of inspection objects on the substrate by the substrate inspection apparatus a plurality of times while switching the imaging conditions that are the conditions of the pattern light to be projected. Acquiring a plurality of images to be performed;
A step of selecting an optimum imaging condition from among the plurality of imaging conditions for each inspection object based on the plurality of acquired images and setting the imaging condition for each selected inspection object in the substrate inspection apparatus. When,
The teaching method of the board | substrate inspection apparatus characterized by performing this.   A program for causing a computer to execute each step of the teaching method for a substrate inspection apparatus according to claim 10.

Images