JP2002181731A - Method for inspecting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an inspection process speed increasingly becomes unable to meet diversification and speed-up of a manufacturing process. SOLUTION: A visual inspection apparatus 10 includes a main unit 12 and a test unit 14. A support stage 22 where a substrate 1 as a body to be inspected is held, a stepping motor 20, a line sensor 34, etc., are set to the test unit 14. A memory 44, an analysis unit 46, etc., are set to the main unit 12. The analysis unit 46 analyzes images on the basis of criteria or an inspection file. A history- recording unit 51 records a history of the inspection file.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a component inspection method. The present invention particularly relates to a technique for inspecting a state of an electronic component mounted on an object to be inspected such as a printed circuit board.

[0002]

2. Description of the Related Art In recent years, with the rapid development of the information society, personal computers and mobile phones have exploded. In addition to simply lowering the price of these products, one of the important factors behind the spread is the diversified designs and the downsizing of the equipment for realizing them. The downsizing of electronic devices has a great influence on the portability of the devices, and further accelerates the development competition for higher integration of electronic components.

To support high-density design of electronic components,
It is indispensable to realize not only the component mounting technology itself but also a technology for inspecting the mounting state. As one of such technologies, an ICT (In-Circuit Tester) for performing a contact-type test has been used for the appearance inspection of a printed circuit board (hereinafter, simply referred to as a “board”) after component mounting.
For example, BGA (Ball Grid Array) and CSP (Chip Si
As technologies such as ze Package and Chip Scale Package have emerged, the mounting method has changed and the density has been further increased, and as a result, it is becoming difficult to respond by a contact-type inspection device. Therefore, the demand for a non-contact type appearance inspection apparatus, particularly using an image recognition technique, is increasing.

Conventional appearance inspections are often performed at the final stage, such as after solder reflow. However, in this case, all inspections are performed when a component mounting method such as the BGA or CSP described above is used. It was difficult to do. Therefore, a method of detecting a cause of a failure early by performing an inspection for each process at a stage before reflow, such as when a component is mounted, has come to be used.

[0005]

However, when the inspection of a component is incorporated at an early stage in the manufacturing process, the subsequent manufacturing process cannot proceed unless the inspection is completed. Moreover,
As a result of the increase in the speed of automatic component mounting machines, the inspection process has not been able to keep up with this speed, and in fact, situations have arisen that can be hindered in shortening the overall manufacturing time.

The present inventor has made the present invention based on the above recognition, and an object of the present invention is to provide an efficient component inspection technology by enabling an inspection with a flexible standard according to a manufacturing situation. is there.

[0007]

One embodiment of the present invention relates to a component inspection method. This method analyzes the photographed image of the object to be inspected based on an inspection file in which the normal state of the object to be inspected is recorded according to the type of the inspected object, so that the mounting state of the component to be mounted on the object to be inspected is analyzed. A method of judging pass / fail, in which a flag is provided for each component in the inspection file, and a value indicating which of the mounted and unmounted states of these components is normal is set in the flag in advance, By referring to the flag in the inspection of the component mounting state, when the component is not mounted, it is possible to output a shortage determination result indicating that the state is normal.

[0008] The "inspected object" herein refers to a substrate on which various electronic components are mainly mounted. The reason for “according to the model” is that even for boards of the same type or the same type, the types of components to be mounted, the number of components, the arrangement, and the like differ depending on the model. The “out-of-stock determination result” is a result of a missing item inspection for determining whether or not a component to be mounted is already mounted. The missing item inspection is positioned as one of the appearance inspections of the substrate.

According to this component inspection method, for example, even if there is a part missing in the manufacturing process, the inspection can be performed in a state where other parts except the part are mounted, so that the inspection flexibly corresponds to the manufacturing process. Can be realized.

According to another aspect of the present invention, there is provided a component inspecting method for analyzing a photographed image of an inspected object based on an inspection file in which a normal state of the inspected object is recorded according to the type of the inspected object. This is a method for determining whether or not a mounting state of a component to be mounted on a body is acceptable, and a flag provided for each component in an inspection file indicates which of the mounted and unmounted as a component status is normal Setting a value, taking a picture of the object to be inspected, specifying a location where the component is to be mounted from the image, recognizing whether or not the component is mounted at the location where the component is to be mounted, and setting a flag. And output the missing part judgment result to pass if the mounted part is normal, or to pass if the unmounted part is normal. And a process.

A component inspection method according to still another aspect of the present invention analyzes a photographed image of an object to be inspected based on an inspection file in which a normal state of the object to be inspected is recorded according to the type of the object. This is a method of determining whether or not a mounting state of a component to be mounted on an inspection object is acceptable. The process of setting the indicated value, the process of referring to the value of the flag at the start of the inspection, the process of removing from the inspection target the component for which mounting is normal, and whether the component for which mounting is normal is mounted Checking whether the product is mounted and outputting a shortage determination result that is acceptable when the device is mounted.

Further, the component inspection method may further include a step of generating a history file in which a value set in a flag of the inspection file is recorded for each component. As a result, it is possible to flexibly perform an inspection that can respond to a manufacturing situation that changes every day.

A component inspection method according to still another aspect of the present invention analyzes a photographed image of an object to be inspected on the basis of a predetermined inspection file in which details regarding inspection are recorded.
A method for determining whether or not a mounting state of a component to be mounted on an inspection object is acceptable, wherein a flag provided for each component in the inspection file sets a value indicating whether or not to be inspected, This includes a step of referring to the value of the flag at the start of the inspection, a step of limiting the inspection target based on the value of the flag, and a step of generating a history file in which the value of the flag is recorded in units of parts. The method may further include a step of calling an arbitrary history from the history file, and a step of reproducing and examining a flag state of the called history.

Any combination of the above components,
What replaced the components and expressions of the present invention among methods, apparatuses, systems, computer programs, and the like is also effective as an aspect of the present invention.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) The appearance inspection apparatus of this embodiment is intended to realize a further efficient and high-speed whole manufacturing process by a component inspection method capable of flexibly responding to a manufacturing situation. Things. Specifically, in a missing item inspection that detects whether a component is mounted on a board,
A flag for each component is prepared in the inspection file, and a value indicating whether mounted or unmounted is normal is set in the flag. Then, this flag is referred to at the time of inspection, and an inspection result corresponding to the value of the flag is output. As a result, when a component for which “unmounted is normal” is actually not mounted, a “passed” inspection result can be output.

Nowadays, the mode of small-scale production of many models has increased, and it is not unusual to switch and manufacture substrates of different models in one production line. in this case,
Since electronic components (hereinafter, simply referred to as “components”) mounted on these components are also of various types, a situation in which some components suddenly run out of stock may frequently occur. However, in the past, in order to set a temporary inspection standard for parts that were temporarily in short supply and to proceed with inspection or manufacturing, it was necessary to rewrite the entire data defining the inspection contents Was. In addition, when it is necessary to return the settings to the original state, the entire data defining the inspection contents must be rewritten in the same manner, so that the operation is complicated. That point,
In the component inspection method according to the present embodiment, it is possible to set a temporary inspection criterion by a simple operation of setting a value of a flag and inspect other components without waiting for mounting of a missing component, and thereafter easily perform the original setting. , The time required for the entire manufacturing process can be reduced.

In addition, since the manufacturing situation changes every day as described above, there may be a request on the site side, for example, "I want to return to the setting several days ago." In the present embodiment, since the above-mentioned flag setting values are accumulated as a history, by referring to this, the same conditions as in the past can be easily read and executed. In addition, since various sets of setting values are stored in one file called a history file, the management is not complicated and the management is easy.

As described above, according to the component inspection method of the present embodiment, it is possible to flexibly respond to the manufacturing situation, so that the inspection can be performed at various timings in the manufacturing process, and the entire process can be efficiently controlled.

FIG. 1 shows the configuration of a visual inspection apparatus. This apparatus scans an inspection surface of an object to be inspected by a line sensor to form an image, and determines whether the component mounting state is acceptable or not by image recognition. By driving the scanning head perpendicular to the scanning direction by the line sensor, images for each line are sequentially obtained, and the inspection is completed by one-dimensional movement of the scanning head. Another type of visual inspection device is to move the inspection surface two-dimensionally, stop it, and repeat this process to take spots one after another. In that case, however, the mechanism system is generally complicated, and the inspection time is generally increased. Is often long. In that respect,
It is more advantageous to use a one-dimensional sensor as in the present embodiment.

The appearance inspection apparatus 10 includes a main unit 12
And a test unit 14. A support table 22 is provided below the test unit 14, and holds the substrate 1 as an object to be inspected. A scanning head 16 and a stepping motor 20 for driving the scanning head 16 are provided above the test unit 14.
A guide 18 such as a linear guide for supporting the scanning head 16
Is provided.

The scanning head 16 has an illumination unit 30, a lens 32 and a line sensor 34. These members are fixed on a frame 36. Lighting unit 30
Incorporates a half mirror and the like. Light reflected vertically upward from the substrate 1 is guided to the lens 32 by the half mirror, passes through the lens 32, and is input to the line sensor 34, which is a one-dimensional CCD sensor. The line sensor 34 scans the substrate 1 line by line and outputs the image data 54 thereof.

The main unit 12 controls the whole of the apparatus as a whole, and can be realized by a CPU, a memory, or other LSI of any computer in terms of hardware, and is loaded into the memory in terms of software. It is realized by a program having an appearance inspection function or the like. Here, functional blocks realized by their cooperation are illustrated. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

The head control unit 40 of the main unit 12 first outputs a lighting control signal 50 to the lighting unit 30 to realize different lighting states according to the contents of the test.
The head control unit 40 further includes a motor control signal 52
To the stepping motor 20 and the test start signal 56 to the memory control unit 42. Step control of the stepping motor 20 is performed by the motor control signal 52, and when the inspection is started, the scanning head 16
Move to the end of. Thereafter, each time one line is scanned, the scanning head 16 advances by one line by the motor control signal 52. On the other hand, with reference to the test start signal 56, the memory control unit 42 controls the writing of the image data 54 to the memory 44, and thereafter, the image data 54 is recorded line by line.

The analysis unit 46 reads out the image data 54 from the memory 44 in parallel with the scanning or after the scanning is completed, and judges pass / fail of each inspection item based on a judgment criterion previously recorded in a judgment criterion storage unit 48. I do. Inspection items include determination of misalignment of parts, missing parts, and missing solder, presence / absence of a solder bridge, incorrect mounting parts, and determination of polarity reversal. In the criterion storage unit 48, a criterion or a reference image regarding pass / fail in the inspection of the mounted components of the board 1 is recorded, and the pass / fail judgment is performed by applying the criterion or the image to the image actually acquired by the line sensor 34. Will be

The inspection file storage unit 47 holds an inspection file in which the normal state of the object to be inspected is recorded according to the model. Hereinafter, the inspection file will be described as being mainly used for a missing item inspection. In the present embodiment, a flag for each component is provided in the inspection file. The inspection file setting unit 49 sets, in each corresponding flag, a value indicating which of the mounted state and the unmounted state of each component to be mounted on the model is normal. The operator of the inspection apparatus sets a value corresponding to the parts procurement status in each flag before the inspection. The inspection file setting unit 49 may record the value of the flag and the name of the operator who has set the value of the flag in the inspection file.

The analysis unit 46 makes a pass / fail judgment according to the value set in the flag with reference to the inspection file.
For example, when the mounting of a certain component is normal, a result is passed if the component is actually mounted, and a reject result is obtained if the component is not mounted. For example, if the unmounted component is normal for a certain component, the result is passed if the component is not actually mounted, and rejected if the component is incorrectly mounted.

As a method of analyzing an image, for example, data relating to characteristics unique to the component such as the color of the surface of the component, the size of the component, the electrode size, and the position of the polar mark are used as analysis reference data as the inspection file storage unit 47 or the judgment reference storage unit 48. In advance. The presence or absence of a component is determined by image processing based on the analysis reference data. In addition, in the case where an erroneous component is mounted, the analysis reference data at the time of non-mounting may be stored in advance so that it is not determined that the component is not mounted. The analysis reference data in this case may be, for example, data on the color, diameter, arrangement, and the like of the cream solder used for the BGA, and data on the color of the elementary board, the color and position of the surface wiring, characters on the surface, and the like. . Thus, even if an erroneous component is mounted when the setting of “not mounted is normal” is not detected as “mounted”, erroneous determination can be prevented. Further, an allowable range of an error in the analysis may be set in advance.

The history recording unit 51 generates a history file in which the value set in the flag of the inspection file is recorded in a set of parts. The history recording unit 51 records the history file in the history file storage unit 53. afterwards,
Each time the inspection is performed, or each time the inspection file setting unit 49 rewrites the inspection file, the history recording unit 51
Updates the history file and adds a new set of flag settings. The history recording unit 51 may further record the name of the operator who has set the value of the flag of the inspection file in the history file. The inspection file setting unit 49 may set the same value set in the past in the inspection file by referring to the history file stored in the history file storage unit 53. This makes it possible to reproduce the inspection performed when the history was recorded.

FIG. 2 exemplifies values set in the flags of the inspection file. The inspection file 80 shown in the figure includes a component name column 82 and a flag 84 corresponding to each component. In the part name column 82, data specifying a part such as “part a” and “part b” is set. The flag 84 is provided corresponding to each component. For example, 1 is set for the flag of the component a, 0 is set for the flag of the component b, 1 is set for the flag of the component c, and 1 is set for the flag of the component d. When the flag is set to 1, the result is “pass” when the component is mounted, and when the flag is set to 0, the result is “pass” when the component is not mounted.

FIG. 3 shows an example of data recorded in the history file. As shown in the table of this figure, the date column 60 records the history update date and time, that is, the date when new data was input to the inspection file. The operator name column 62 records the name of the operator who has input new data into the examination file. In the flag setting columns 63 to 68, the component a
The set values of the flags corresponding to .about.d are respectively recorded.
For example, the operator on December 1, 2000 is "Mr. A"
And the flag setting values of the parts a to d on that day are “1”, “0”, “1”, and “1”, respectively. Further, for example, when the history file is referred to on December 4 of the same year and the set value of December 3, which is the previous day, is used as it is, a simplified setting 70 as shown in the figure may be recorded.

FIG. 4 is a flowchart showing the procedure of the component inspection method according to the embodiment. First, the model of the inspection object is specified, and an inspection file corresponding to the model is set (S10). Then, a value corresponding to the component mounting schedule at the time of the inspection is set to the flag provided for the shortage inspection in the inspection file (S12). Next, the whole image captured by scanning the subject is acquired (S14). After the image is captured, the location where the component is to be mounted is specified (S1).
6). For example, a specific method of generating a close-up image by enlarging a part location included in a captured image may be used. After specifying the component location, the actual component mounting state is detected by image analysis (S18).

Next, when it is detected that the device is already mounted (S20Y), 1 is set to the detection flag a (S22).
If it is detected that the device is not mounted (S20N), 0 is set to the detection flag a (S24). Next, the flag of the inspection file is referred to (S26). Next, the value of this flag is compared with the value of the detection flag a (S28). If the values match, a pass result is output, and if they do not match, a reject result is output (S30). If other parts to be inspected still remain (S32Y), the processes from S16 to S30 are repeated. After all parts have been inspected (S32
N), and output the entire inspection result (S34).

If the result of the determination in S30 is unacceptable, a method may be adopted in which the inspection of the remaining parts is stopped there. Further, after the missing item inspection, the entire inspection result may be output after other inspection items for detecting misregistration, solder slippage, and the like are completed.

(Second Embodiment) In this embodiment,
As a criterion used for the pass / fail judgment of the missing item inspection, not the analysis reference data but the reference image is stored in the inspection file storage unit 4.
7 or that stored in the criterion storage unit 48,
Different from the embodiment. Then, the mounting state of the component is determined by pattern matching between the component image obtained from the captured image and the reference image. The configuration of the visual inspection device according to the present embodiment is substantially the same as the configuration of the same device according to the first embodiment.

FIG. 5 shows an example of a reference image used for a missing item inspection. In the present embodiment, a reference image of each component to be mounted is stored in advance in the determination reference storage unit 48 as a reference used for analyzing the component image acquired in the inspection. The mounted image 90 as a reference image example includes a CPU 9
2 is shown. The unmounted image 94 shows a BGA cream solder 96 used for mounting the CPU 92. As the non-mounted image 94, an image of the elementary substrate may be prepared. Either of these reference images is used for inspection as a determination criterion for analysis according to the flag setting value of the inspection file. For example, an image obtained by scanning a component whose mounting is normal is determined to be acceptable or unacceptable by pattern matching with the mounted image 92. For example, an image obtained by scanning a component whose mounting is normal is determined to be acceptable or unacceptable by pattern matching with the unmounted image 94.
The allowable range of the matching error may be set in the test file storage unit 47 or the criterion storage unit 48 in advance.

FIG. 6 is a flowchart showing the procedure of the component inspection method according to the embodiment. The process from S40 to S46 is the same as the process from S10 to S16 of the first embodiment shown in FIG.

After specifying the part location, a value corresponding to the part is acquired by referring to the flag of the inspection file (S4).
8). As a result of the reference, if the mounted state is set to be normal (S50Y), the mounted image is selected from the determination criterion storage unit 48 as the reference image (S52). If the non-mounted image is set to be normal (S50N), the unmounted image is selected as the reference image (S54).

Next, the image is analyzed by pattern matching between the component image obtained from the photographed image and the reference image (S56). Next, the pass / fail of the missing item inspection is determined, and the result is output (S58). If other components to be inspected still remain (S60Y), the inspection steps from S46 to S58 are repeated. After all parts have been inspected (S
60N), and outputs the entire inspection result (S62).

(Third Embodiment) In the present embodiment,
This is different from the first or second embodiment in that when a value indicating that the non-mounting is normal is set in the flag of the inspection file, the missing item inspection for the component is skipped. The configuration of the visual inspection device according to the present embodiment is substantially the same as the configuration of the same device according to the first embodiment.

FIG. 7 is a flowchart showing the procedure of the component inspection method according to the embodiment. The processes from S70 to S76 are the same as the processes from S10 to S16 of the first embodiment shown in FIG.

After specifying the part location, the flag of the inspection file is referred to (S78). Next, if the mounted state is set to be normal (S80Y), the mounted state of the component is detected by image analysis as in the first embodiment (S82), and the pass / fail regarding the part missing inspection is performed. Is determined and the result is output (S88). When it is set that the non-mounting is normal (S80N), the inspection step of the pass / fail judgment by the image analysis is skipped (S84). The steps from S76 to S88 are repeated until all parts have been inspected (S90), and finally the entire inspection result is output (S92).

(Fourth Embodiment) In the present embodiment,
The third embodiment is different from the first to third embodiments in that a value indicating whether or not to be inspected for each component is set in a flag of the inspection file. As a result, it is possible to set a part to be temporarily removed from the inspection target in accordance with the manufacturing situation, and then easily return the setting. Inspection is skipped for components that are not inspected, as in the third embodiment.

The analysis unit 46 refers to the value of the flag provided in the inspection file at the start of the inspection, and limits the inspection target based on the value. The value of the flag is recorded in the history file for each component. Then, an arbitrary history is called from the history file, and the flag state is reproduced by referring to the value of the flag. This makes it possible to reproduce the inspection performed when the history was recorded. It should be noted that the inspection file may be set not only with a value indicating whether or not the component is to be inspected, but also with a value indicating whether the component is mounted or not, which is normal.

The present invention has been described based on several embodiments. These embodiments are exemplifications, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and that such modifications are also within the scope of the present invention. is there. Less than,
Modifications will be described.

In the component inspection method of this embodiment, it is mainly assumed that the component mounting process is performed before the reflow of the mounted component, but this may be performed as a process after the reflow. In this case, the order with other inspection items may be set arbitrarily.

[0046]

According to the present invention, an electronic component mounted on a substrate can be inspected by a more efficient method.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a visual inspection device.

FIG. 2 is a diagram exemplifying values set in a flag of an inspection file.

FIG. 3 is a diagram illustrating data recorded in a history file.

FIG. 4 is a flowchart illustrating a procedure of a component inspection method according to the first embodiment.

FIG. 5 is a diagram illustrating an example of a reference image used for a missing item inspection.

FIG. 6 is a flowchart illustrating a procedure of a component inspection method according to a second embodiment.

FIG. 7 is a flowchart illustrating a procedure of a component inspection method according to a third embodiment.

[Explanation of symbols]

10 Appearance inspection device, 12 Main unit, 14
Test unit, 46 analysis unit, 47 inspection file storage unit, 48 judgment criterion storage unit, 49 inspection file setting unit, 51 history recording unit,
53 history file storage unit.

Claims (6)

[Claims] 1. A mounting state relating to a component to be mounted on the inspection object by analyzing a photographed image of the inspection object based on an inspection file in which a normal state of the inspection object is recorded according to the type of the inspection object. A flag is provided for each component in the inspection file, and a value indicating in advance whether the mounted or unmounted state of the component is normal is set in the flag. A component out-of-stock judgment result indicating that the state of the component is normal even when the component is not mounted, by referring to the flag in the inspection of the mounting state of the component. Inspection methods. 2. A mounting state relating to a component to be mounted on the object to be inspected by analyzing a photographed image of the object to be inspected based on an inspection file in which a normal state of the object to be inspected is recorded according to the type of the object. A step of setting a value indicating which of the mounted or unmounted is normal as the status of the component, in a flag provided for each component in the inspection file, Photographing the object to be inspected, specifying a location where the component is to be mounted from the image thereof; recognizing whether the component is mounted at the location where the component is to be mounted; and The process of outputting a missing part determination result to be referred to when the mounted component is normal when the component is mounted, and to be passed when the mounted component is normal, or when the component that is not mounted normally is not mounted. Including Parts inspection method and butterflies. 3. A mounting state relating to a component to be mounted on the inspection object by analyzing a photographed image of the inspection object based on an inspection file in which a normal state of the inspection object is recorded according to the type of the inspection object. A step of setting a value indicating which of the mounted or unmounted is normal as the status of the component, in a flag provided for each component in the inspection file, A process of referring to the value of the flag at the start of the inspection, a process of removing a component whose mounting is normal from the inspection target, and checking whether a component whose mounting is normal is mounted or not, Outputting a shortage determination result that is acceptable when the component is mounted. 4. The component inspection method according to claim 2, further comprising a step of generating a history file in which a value set in a flag of the inspection file is recorded for each component. 5. A method for judging whether or not a mounting state of a component to be mounted on the object to be inspected by analyzing a photographed image of the object to be inspected based on a predetermined inspection file in which contents relating to the inspection are recorded. Setting a value indicating whether or not to be inspected in a flag provided for each component in the inspection file; a step of referring to the value of the flag together with the start of inspection; A component inspection method, comprising: limiting an inspection target based on the information; and generating a history file in which the value of the flag is recorded in component units. 6. The method according to claim 4, further comprising: calling an arbitrary history from the history file; and reproducing and checking a flag state of the called history. Part inspection method described.