JP6093507B2 - Electronic component mounting circuit board short inspection method - Google Patents

Description

  The present invention relates to an electronic component mounting circuit board short inspection method, and more particularly, to an electronic component mounting circuit board short inspection method for inspecting a short portion based on heat generation information from an electronic component mounting circuit board.

  The circuit board is checked for abnormalities in the wiring pattern or the like before the component is mounted, and the electronic component is mounted on the circuit board that does not have a defect such as a short circuit. For mounting electronic components for surface mounting, apply cream solder etc. to the pattern of the circuit board to be mounted, mount the electronic component on the applied solder, blow hot air on the circuit board and the mounting component, and melt the solder Join. In addition, after the circuit board is assembled, confirmation of the bonding state between the electronic component and the circuit board, and a short circuit inspection due to a soldering error or the like are performed.

  Patent Document 1 discloses an inspection apparatus that inspects a connection state between a plurality of electrodes of a semiconductor chip and a plurality of electrodes corresponding to the printed wiring board. According to Patent Document 1, by irradiating a laser beam, the electronic component is heated to a predetermined state by a heating unit that heats the electronic component from the outside, and then the temperature distribution of the heated electronic component is measured via the measurement unit. The connection state between each electrode of the electronic component and the corresponding electrode of the printed wiring board is inspected by the inspection means based on the measurement result obtained.

Japanese Patent Laid-Open No. 11-201926

  In recent years, since the pitch of a pattern is narrowed with high-density mounting of a circuit board, a short circuit is likely to occur due to a soldering error when electronic components are mounted on the circuit board. For this reason, the substrate immediately after being assembled with the SMD (Surface Mount Device) is mixed with a short-circuited substrate surface or the like, the main cause of which is the solder bridge during component mounting. This is due to a short circuit caused by the above. In addition to a short circuit due to a solder mistake, a short circuit due to a conductive foreign matter may occur.

  After mounting the electronic components on the circuit board, energize the electronic component mounting circuit board, measure the signal level etc. of each part of the electronic component mounting circuit board with a board tester etc., and check for any abnormalities such as short circuit Yes.

  However, it is necessary to confirm whether the power supply pattern is short-circuited before energizing the electronic component mounting circuit board. When the power supply pattern is short-circuited, it takes time and labor to visually check the entire substrate in order to find the short-circuited portion. Furthermore, when an electronic component is mounted at a shorted location, it is difficult to confirm visually.

  For this reason, the resistance value of the pattern was measured with a tester or the like while looking at the circuit diagram, and the short-circuited portion was found while the short-circuited portion was estimated from the change in the resistance value, and the repair was performed. For this reason, it takes time to identify the short-circuited portion, and the work efficiency is poor. Accordingly, there is a demand for efficiency in the repair work of the short circuit.

  Further, in order to detect a short portion, it is possible to identify a heat generation portion by thermography by imaging a circuit board on which a component is mounted using an infrared radiation thermometer. However, the heat generation location extracted by thermography may be different from the short-circuit location on the actual electronic component mounting circuit board. This is because, for example, the heat generated at the short portion becomes a heat sink by using a GND pattern having a large area adjacent to the short portion, and the short portion is radiated. This is because current flows in a thin pattern away from the shorted portion, and that portion generates heat. For this reason, it may take time because the short-circuited portion cannot be uniquely identified from the heat-generating portion.

  Therefore, the present invention applies a current that does not impose a burden on the electronic components mounted on the circuit board to cause the board to generate heat, detect the heat generation point by thermography, and short-circuit the database based on the heat generation point. It is an object of the present invention to provide a method for inspecting a short circuit of an electronic component-mounted circuit board that can perform inspection and repair work in a short time by estimating the location.

In order to achieve the above object, the present invention provides a method for inspecting a short circuit of an electronic component mounted circuit board for identifying a short circuit location after mounting the electronic component on the circuit board. Supplying a small current, imaging the temperature distribution of the electronic component mounting circuit board by supplying a current, extracting a heat generation point on the electronic component mounting circuit board by thermography, and setting the heat generation point to the preset electronic Corresponding to the area information indicating the position on the component mounting circuit board, the ID information for identifying the electronic component mounting circuit board, using the ID information of the electronic component mounting circuit board and the area information of the heat generation point as a key; For each ID information, past short locations based on one or more area information corresponding to heat generation locations on the electronic component mounting circuit board are stored. It was based on the database, and identifies the short portion from the heating portion of the electronic component mounting circuit board.

In addition, in the electronic component mounting circuit board short inspection method of the present invention, the short circuit location is specified as an estimated short circuit location estimated as a short circuit location from the heat generation location on the electronic component mounting circuit board. If it cannot be confirmed as the short-circuited portion, the heat-generating portion that is not caused as the short-circuited portion is selected and masked, the masked heat-generating portion is removed, and the area information of the reduced heat-generating portion is used as a key again to the database. The short portion is estimated based on the above, only the newly estimated short portion is displayed, and the short portion is identified by repeating the estimation and displaying the estimated short portion .

Also, short test method of the electronic component mounting circuit board of the present invention, the estimated short portions that match the previous conditions the mask, characterized in that it excluded the estimated short portion after the mask.

  Also, the electronic component mounting circuit board short inspection method of the present invention is characterized in that a step of cooling the electronic component mounting circuit board is provided before supplying current to the power supply pattern of the electronic component mounting circuit board. To do.

  According to the present invention, a current that does not impose a burden on an electronic component mounted on a circuit board is applied, a heat generation location on the electronic component mounting circuit board is extracted by thermography, and the position of the heat generation location is used as a key. By obtaining the short location from the database storing the short locations that have occurred in the past on the electronic component mounting circuit board, the short location can be found in a short time, and the efficiency of the repair work can be improved.

  Further, by cooling the electronic component mounting circuit board before supplying current to the power supply pattern of the electronic component mounting circuit board, it is possible to more reliably extract the heat generation location by thermography.

  In addition, similar accidents can be reduced by feeding back a report of a shorted portion of the circuit board to the manufacturing process.

(A) is a figure which shows the structure of the short test | inspection apparatus for carrying out the short test | inspection of the electronic component mounting circuit board which mounted the electronic component on the circuit board, (b) is an electronic component mounting circuit board via protection resistance It is the figure which connected the power supply device. It is a flowchart which shows the flow of the short test | inspection of an electronic component mounting circuit board. It is a figure which shows the example which divided | segmented the electronic component mounting circuit board vertically and horizontally, and displayed the divided area on the monitor screen by the grid. It is a figure which shows the heat_generation | fever location of the electronic component mounting circuit board displayed on the monitor. It is a figure which shows an example which displayed on the monitor the position of the short part estimated of the electronic component mounting circuit board. It is a figure which shows the example which masked a part of division area on a monitor.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment for carrying out an electronic component mounting circuit board short inspection method according to the present invention will be described with reference to the drawings. The present invention applies a current that does not burden the electronic component mounted on the electronic component mounted circuit board to the power supply pattern to heat the electronic component mounted circuit board, and extracts the heat generation location by thermography, The short part is estimated from the database based on the heat generation part, so that the inspection and repair work for the short circuit of the power supply can be performed in a short time.
[Configuration of short inspection equipment]

  FIG. 1A is a diagram showing a configuration of a short inspection apparatus for inspecting a short of an electronic component mounting circuit board in which an electronic component is mounted on a circuit board, and FIG. 1B is an electronic component through a protective resistor. It is the figure which connected the power supply device to the mounting circuit board. In the following description, a board before electronic component mounting is referred to as a circuit board, and an electronic component mounted circuit board is referred to as an electronic component mounting circuit board.

  As shown in FIG. 1, the short inspection apparatus 1 includes an infrared radiation thermometer 5 for imaging an electronic component mounting circuit board 3 to detect a heat generation point, and a temperature distribution by thermography from an imaging signal of the infrared radiation thermometer 5. Is converted into a color image, the image processing device 6 that extracts the heat generation portion by processing the temperature image data, the monitor 7 that displays the image data and the processing result of the image processing device 6, and the key information from the image processing device 6 And a database 10 for estimating and outputting a short portion based on the database. A power supply device 17 is also provided for supplying power to the electronic component mounting circuit board, which is the board to be inspected, via the connector 15.

  The electronic component mounting circuit board 3 is a circuit board on which SMD (surface mounted component) or the like is mounted by soldering, and a short circuit related to the power supply is found in the power supply short inspection immediately after the component mounting. is there. The electronic component mounting circuit board 3 is installed so as to be horizontal via the support column of the cradle 20 at the time of inspection.

  The infrared radiation thermometer 5 forms an image of infrared rays emitted from the electronic component mounting circuit board 3 with a lens, detects the infrared rays with an infrared detection element, and measures the temperature from the detected signal.

  The image processing device 6 converts an analog signal from the infrared radiation thermometer 5 into digital data, converts the converted digital data into a color corresponding to the level of temperature, and displays the two-dimensionally on the monitor 7 Is output. Further, the image processing device 6 stores in the memory the temperature data converted from the analog signal of the infrared radiation thermometer 5 into digital data, and processes the data stored in the memory to extract the heat generation temperature and its location (position). To do.

  The database 10 is a PC or the like in which software for managing the database is incorporated, accumulates information on fault locations that have occurred in the past for each electronic component mounting circuit board, and searches for short locations on the electronic component mounting circuit board using key information. It is something that can be done. The failure location information stored in the database 10 is obtained by associating the location of the short location detected from the heat generation location extracted by thermography with the heat generation location. The position on the thermography is determined by area information set by equally dividing the surface of the electronic component mounting circuit board vertically and horizontally.

  As described above, the database 10 stores short locations corresponding to the area information indicating the heat generation locations on the electronic component mounting circuit board for each ID information for specifying the electronic component mounting circuit board. The heat generation location extracted by thermography may be different from the short-circuit location on the actual electronic component mounting circuit board. Since these pieces of information are stored in the database 10, the heat generation is performed by searching the database 10. The short part can be specified from the part.

  Thereby, it is possible to search the database 10 for similar short locations that occurred in the past using the ID and heat generation location for specifying the electronic component mounting circuit board 3 as keys. A number of database configurations, search methods, and the like are disclosed, and these known databases can be used.

  The power supply device 17 applies a current that does not become a burden to the electronic components of the electronic component mounting circuit board 3 through the power supply pattern, and can gradually vary the magnitude of the current that flows. ing. As shown in FIG. 1B, the power supply device 17 supplies current to the electronic component mounting circuit board 3 through the protective resistor 19. Further, the power supply device 17 has a current limit function so as not to flow a predetermined current value or more.

  As described above, in the database 10 of the short inspection apparatus 1, the data of the short portion corresponding to the portion where the heat is generated is stored for each ID of the electronic component mounting circuit board 3. The data stored in the database 10 includes data originating from the pattern layout unique to the electronic component mounting circuit board and data originating from the mounting components. Will occur more frequently. For this reason, it is possible to search for a short portion with a high probability by accumulating data relating to past shorts and utilizing the accumulated data.

[Short inspection procedure]
Next, the procedure for short inspection of the electronic component mounting circuit board will be described with reference to FIGS. FIG. 2 is a flowchart showing a flow of a short inspection of an electronic component mounting circuit board, and FIG. 3 shows an example in which the electronic component mounting circuit board is divided vertically and horizontally and the divided areas are displayed on the monitor screen with grids. FIG. 4 is a diagram showing a heat generation location of the electronic component mounting circuit board displayed on the monitor, and FIG. 5 is a diagram showing an example of displaying on the monitor the position of the estimated short location of the electronic component mounting circuit board. FIG. 6 is a diagram showing an example in which a part of the divided area on the monitor is masked.

  First, it is confirmed by a tester or the like whether the power line of the electronic component mounting circuit board 3 on which the electronic component is mounted is short-circuited (step S1). If the power line of the electronic component mounting circuit board 3 is not short-circuited (Yes in step S2), the inspection is not necessary, and the inspection is terminated with the electronic component mounting circuit board 3 as a good product.

  If the power line of the electronic component mounting circuit board 3 is short-circuited (No in step S2), first, the surface of the electronic component mounting circuit board 3 is inspected (step S3). Before the inspection, the electronic component mounting circuit board 3 is placed on the column of the cradle 20 so that the optical axis of the lens of the infrared radiation thermometer 5 is perpendicular to the horizontally installed electronic component mounting circuit board 3. Install horizontally. At this time, the power supply device 17 is connected to the electronic component mounting circuit board 3 via the connector 15 (step S4). The infrared radiation thermometer 5 is connected to the image processing device 6.

  Next, the electronic component mounting circuit board 3 to be inspected is imaged by the infrared radiation thermometer 5 and adjusted so that the electronic component mounting circuit board 3 is projected on the monitor 7 in a predetermined orientation, position and size (step). S5). This board positioning adjustment is determined in advance for each electronic component mounting circuit board 3, and the same adjustment is performed for each electronic component mounting circuit board 3, whereby an image is picked up by the infrared radiation thermometer 5 under the same conditions. .

  Further, the ID of the electronic component mounting circuit board 3 to be inspected is input to the image processing apparatus 6. After inputting the ID of the electronic component mounting circuit board 3 to the image processing device 6, the image processing device 6 divides the electronic component mounting circuit board 3 vertically and horizontally from the size and shape of the electronic component mounting circuit board 3, as shown in FIG. The divided area shown is displayed on the monitor 7 screen in grit.

  As shown in FIG. 3, the electronic component mounting circuit board 3 on the screen of the monitor 7 is divided into five parts A to E in the horizontal direction and five parts 1 to 5 in the vertical direction. Thereby, the electronic component mounting circuit board 3 on the monitor 7 screen is divided into 25 areas from divided areas A1 to E5. In subsequent processing, each position of the electronic component mounting circuit board 3 is managed by an area number assigned to the divided area. The above-described divided areas are for explanation, and the number of vertical and horizontal divisions is not limited to this.

  Next, a current is supplied to the power supply terminal of the electronic component mounting circuit board 3 by the current regulator of the power supply device 17 via the connector 15 (step S6). The power supply device 17 applies a current that does not impose a burden on the electronic circuit components of the electronic component mounting circuit board 3, and can vary the magnitude of the current flowing through the electronic component mounting circuit board 3. ing. Further, the current regulator of the power supply device 17 has a current limit function so as not to flow a predetermined current or more. The current is gradually increased from 0 (zero) and a current of about 0.2 A to 0.3 A is applied.

  A current is applied to the electronic component mounting circuit board 3, and an image captured at that time is color-coded according to temperature by thermography and displayed on the monitor 7. Thereby, a temperature distribution image is obtained by thermography. The temperature distribution image is stored in the memory of the image processing device 6 (step S7). The address of the memory storing the temperature distribution image data and the position on the monitor 7 have a one-to-one correspondence. The memory data stores a numerical value indicating the temperature.

Next, the image processing device 6 processes the temperature distribution image data stored in the memory to extract the heat generation temperature and its location (position) (step S8).
FIG. 4 shows a portion where the electronic component mounting circuit board displayed on the monitor 7 is generating heat. The heat generation points shown in FIG. 4 are area numbers A2 and B3 indicated by circles and area numbers C1, C4 and D2 indicated by squares.

  The heat generation position is extracted from the memory storing the temperature data of the temperature distribution image in the order of the highest temperature. The extracted heat generation position is converted into an area number on the electronic component mounting circuit board 3. As another heat generation position extraction method, a threshold value may be set in advance, and a position where a temperature of heat generation equal to or higher than the threshold value is extracted may be set as the heat generation position.

  The image processing apparatus 6 of the short inspection apparatus 1 outputs the ID of the electronic component mounting circuit board 3 and the extracted heat generation position data to the database 10 as search conditions of the database 10 (step S9). The short location estimated from the database 10 is searched using the ID of the electronic component mounting circuit board 3 and the area number of the heat generation location as keys, and the search result is displayed on the monitor 7 (step S10). FIG. 5 shows an example of searching the database 10 and displaying the estimated position of the short part on the monitor. As shown in FIG. 5, an X mark indicating the short position is displayed in the area number D1.

  The estimated short part displayed on the monitor 7 is confirmed (step S11). When a short is observed (Yes in step S12), the short portion is repaired (step S13). Thereafter, the process proceeds to step S15.

  Further, when the estimated short-circuit location cannot be confirmed (No in step S12), for example, the divided area that is estimated to be a heat generation location not caused by the short visually confirmed on the monitor 7 by the operator The area number is masked so as to be excluded from the information on the heat generation point (step S14). FIG. 6 shows an example in which a part of the divided area on the monitor is masked. As shown in FIG. 6, the area number C1 indicated by diagonal lines is masked to be excluded from the heat generation point.

  The masked heat generation part is removed, the process proceeds to step S9, and the short part is estimated with reference to the database 10 again. At this time, since the area information of the heat generation portion is reduced, the estimated short portion is estimated to have more short portions than before masking, but as shown in FIG. In the area number D1 that is estimated to be a short place under the condition, the x mark indicating the short place is not displayed, and only the newly estimated short place is displayed with the x mark shown in the area numbers D4 and E4.

  If the estimated short part cannot be confirmed, the heat generation part selected by the operator is masked again, and the heat generation part masked at the time of accessing the database 10 is excluded, and the processes from step S9 are repeated. Like that.

  In step S15, when inspection of both sides of the electronic component mounting circuit board 3 is necessary, preparation for inspecting the back surface of the electronic component mounting circuit board 3 is performed (step S16), and the process proceeds to step S4 to mount the electronic component mounting. The other surface of the circuit board 3 is inspected. If the electronic component mounting circuit board 3 inspection is only on one side in step S15 (No in step S15), the inspection ends.

  As described above, current that does not impose a burden on the electronic components mounted on the circuit board is applied, the position of heat generation is extracted by thermography, and past short-circuited locations are stored using the position of heat generation as a key. By obtaining the short part from the database, the short part can be found in a short time and the efficiency of the repair work can be improved.

[Other Embodiments of Short Inspection]
In the above-described short inspection, the heat generation portion of the electronic component mounting circuit board 3 is extracted at room temperature. However, when the sensitivity of the thermography is low or the heat generation temperature from the electronic component mounting circuit board 3 is low, the power supply A step of cooling the electronic component mounting circuit board may be added before supplying current to the pattern. By cooling the electronic component mounting circuit board 3, it is possible to make the heat generation point stand out, and the accuracy of finding the short point is improved.

  The electronic component mounting circuit board 3 is cooled by cooling a case housing the electronic component mounting circuit board 3 or by providing a cooling mechanism in the cradle 20 shown in FIG. You may make it spray on the circuit board 3. FIG. Furthermore, in order to eliminate the influence of the indoor illumination lamp, the light may be turned off or the inspection may be performed in a dark room.

  As described above, before the current is supplied to the power supply pattern of the electronic component mounting circuit board 3, a process of cooling the electronic component mounting circuit board 3 is provided or the surroundings are darkened to generate heat in the electronic component mounting circuit board 3. Since the location can be easily extracted, the accuracy of finding the short location can be improved.

  As described above, according to the present invention, a current that does not cause a burden on the electronic component mounted on the circuit board is applied, and a heat generation location on the electronic component mounting circuit board 3 is extracted by thermography, By using the location information of the heat generation points as a key, the short locations are obtained from the database of the short locations that have occurred in the past on the electronic component mounting circuit board 3 so that the short locations can be found in a short time and the efficiency of the repair work Is achieved.

  Further, by cooling the electronic component mounting circuit board 3 before supplying current to the power supply pattern of the electronic component mounting circuit board, it is possible to more reliably extract the heat generation location by thermography.

In addition, similar accidents can be reduced by feeding back a report of a shorted portion of the circuit board to the manufacturing process.

  The present invention can be embodied in many forms without departing from its essential characteristics. Therefore, it is needless to say that the above-described embodiment is exclusively for description and does not limit the present invention.

DESCRIPTION OF SYMBOLS 1 Short inspection apparatus 3 Electronic component mounting electronic component 5 Infrared radiation thermometer 6 Image processing apparatus 7 Monitor 10 Database (computer)
15 Connector 17 Power supply 19 Protection resistance 20 Receiving base

Claims (4)

An electronic component mounting circuit board short inspection method for identifying a short circuit location after mounting an electronic component on a circuit board,
Supply less current than normal use to the power pattern of the electronic component mounting circuit board,
Supply a current to image the temperature distribution of the electronic component mounting circuit board and extract the heat generation location on the electronic component mounting circuit board by thermography,
The electronic component mounting is performed using the ID information of the electronic component mounting circuit board and the area information of the heat generating portion as keys, corresponding to the area information indicating the position on the electronic component mounting circuit board that is set in advance. Based on a database storing ID information for specifying a circuit board and past short locations based on one or more area information corresponding to heat generation locations on the electronic component mounting circuit board for each ID information,
A method for inspecting a short circuit of an electronic component mounting circuit board, wherein a short circuit portion is specified from a heat generation position of the electronic component mounting circuit board. The short part is identified as an estimated short part estimated as a short part from a heat generation part based on the database, on the electronic component mounting circuit board, and cannot be confirmed as the short part,
Select and mask the exothermic location that does not originate as the short location, remove the masked exothermic location, and use the area information of the reduced exothermic location as a key to again estimate the short location based on the database, 2. The electronic component mounting circuit according to claim 1, wherein only the newly estimated estimated short location is displayed, and the short location is specified by repeating confirmation of the estimated and displayed estimated short location. Substrate short inspection method.   3. The method for inspecting a short of an electronic component-mounted circuit board according to claim 2, wherein the estimated short portion that matches the condition before the masking is excluded from the target of the estimated short portion after the masking.   4. The method according to claim 1, further comprising a step of cooling the electronic component mounting circuit board before supplying a current to a power supply pattern of the electronic component mounting circuit board. 5. Short circuit inspection method for electronic component mounting circuit boards.

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