JP2008249368A - Circuit board inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate probing to each probing point. <P>SOLUTION: This device includes a storage part 7 for storing probing position information Dp on four or more mark points specified on a circuit board 10 and on a probing point to be probed by probes 4a, 4b; a camera 8 for acquiring image data Dc on each mark point on the circuit board 10; and a control part 9 for calculating position conversion parameters A-F based on the probing position information Dp on three mark points corresponded beforehand to a probing point among each mark point and on the image data Dc, when the probing point on the circuit board 10 placed on a placing stand 2 are probed by the probes 4a, 4b, and performing position conversion processing using the calculated position conversion parameters A-F to the probing position information Dp on the probing point, to thereby calculate actual position information Dpr on the probing point. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a circuit board inspection apparatus for probing a probe at each probing point to electrically inspect a board.

  As this type of circuit board inspection apparatus, a circuit board inspection apparatus disclosed in Japanese Patent Application Laid-Open No. 8-262114 is known. In this circuit board inspection apparatus, design data such as CAD data used when designing a standard model board (reference board) of a circuit board is stored in advance in a memory as reference position coordinate data (reference position information). Each time necessary correction processing is performed so that the correspondence between the reference position coordinate data for the board inspection apparatus placed at the position and the actually measured position coordinate data at the corresponding position of the circuit board is obtained, and obtained after correction The probe is moved based on the corrected position coordinate data. Specifically, a pattern matching method based on the reference correlation data acquired in advance from the reference position mark of the standard model board and the position corresponding to the reference position mark on the circuit board using the normalized correlation coefficient by the position correction camera. Substrate position conversion parameters are obtained using the actual measurement values obtained by measurement, and the movement position is corrected by performing substrate position correction processing based on the substrate position conversion parameters, and the probe is moved to the measurement point (probing). Point) accurately.

As a result, according to this circuit board inspection apparatus, even if the circuit board is displaced at a predetermined position or the circuit board itself is distorted due to expansion / contraction, the probe can be It becomes possible to contact the measurement point accurately.
JP-A-8-262114 (2nd page)

  However, this conventional circuit board inspection apparatus has the following problems to be improved. That is, in the conventional circuit board inspection apparatus, generally, a measurement point of the entire circuit board is obtained using one board position conversion parameter obtained by using three reference position marks defined at the corners of the circuit board. Correction processing is performed. However, the distortion due to expansion / contraction generated on the circuit board itself is not uniform over the entire circuit board on which the components are mounted, and the density of the wiring pattern is high or the mounting density is low when electronic components are mounted. This is different for each area of the circuit board. Therefore, since the conventional circuit board inspection apparatus uses only one board position conversion parameter, the probe is used as a measurement point for boards that are small in size or that are made of a material that has little distortion due to expansion / contraction. Although it is possible to accurately contact the probe, it is difficult to accurately contact the probe with the measurement point for a large-sized substrate or a substrate made of an inexpensive material having a large distortion due to expansion / contraction. There is a problem that a region may occur.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a circuit board inspection apparatus that can enable accurate probing for each probing point.

  To achieve the above object, a circuit board inspection apparatus according to claim 1 includes a storage unit that stores reference position information about four or more mark points defined on a circuit board and a probing point for probing a probe, and an inspection. When probing the probe to the probing point on the circuit board disposed at the inspection position and a camera that acquires measured position information about each mark point on the circuit board disposed at the position The position conversion parameter is calculated based on the reference position information and the measured position information for the three mark points previously associated with the probing point among the mark points, and the calculated position conversion parameter is calculated. Probing is performed by performing position conversion processing using the reference position information on the probing point. And a calculator for calculating the actual position information.

  The circuit board inspection apparatus according to claim 2, wherein the calculation unit includes three mark points that are closer to the probing point among the mark points. The three mark points correspond to the probing points.

  In the circuit board inspection apparatus according to claim 1, when the probe is probed to the probing point on the circuit board disposed at the inspection position, the arithmetic unit previously corresponds to the probing point among the mark points. Probing is performed by calculating position conversion parameters based on the reference position information and the measured position information for the three marked points, and performing position conversion processing using the calculated position conversion parameters on the reference position information for the probing points. Real position information about the point is calculated. Therefore, according to this circuit board inspection apparatus, a large-sized board and distortion due to expansion / contraction are large by associating in advance the three mark points close to the probing point with respect to the probing point. Reference position information of mark points that are close to the probing point where the probe is actually probed even for circuit boards where the generated distortion is not uniform throughout, such as circuit boards made of inexpensive materials And the actual position information of the probing point using the position conversion parameter for the local area (area defined by three mark points adjacent to the probing point in the circuit board) calculated based on the measured position information As a result, the error of the position conversion parameter can be reduced, so that the probe can be set to the desired probing point. It can be a layer accurately contact.

  According to the circuit board inspection apparatus of the second aspect, the calculation unit has three mark points that are closer to the probing point Pt among the mark points (the closest mark point, Local mark closest to the probing point for probing the probe by identifying the adjacent mark point and the next closest mark point) and making these three mark points correspond to this probing point. Since the actual position information of the probing point can be calculated using the position conversion parameter for a specific region, the error of the position conversion parameter can be further reduced. As a result, the probe can be more accurately contacted with the desired probing point. Can be made.

  The best mode of a circuit board inspection apparatus according to the present invention will be described below with reference to the accompanying drawings.

  First, the configuration of the circuit board inspection apparatus 1 will be described with reference to the drawings.

  A circuit board inspection apparatus 1 shown in FIG. 1 includes a mounting table 2, XYZ moving mechanisms 3a and 3b, probes 4a and 4b, a measuring unit 5, an operation unit 6, a storage unit 7, a camera 8, and a control unit 9. In addition, the circuit board 10 to be inspected can be electrically inspected. The mounting table 2 is configured to be able to mount a circuit board 10 having a rectangular outer shape. Actually, a clamp mechanism or the like for fixing the circuit board 10 to the mounting table 2 is provided, but illustration and description thereof are omitted. The XYZ moving mechanisms 3a and 3b (hereinafter also referred to as “moving mechanisms 3a and 3b”) move the probe 4a and the moving mechanism 3b moves the probe 4b according to the control of the control unit 9. As a result, the probes 4a and 4b are probed to a plurality of probing points Pt (see FIG. 2) defined in advance on the surface of the circuit board 10. In this case, the X coordinate axis and the X coordinate axis are orthogonal coordinate axes in a virtual plane including the circuit board 10 mounted on the mounting table 2, and the Z coordinate axis is a coordinate axis in a direction orthogonal to the virtual plane. is there. In this example, the probes 4a and 4b are configured as contact-type inspection probes. The probe in the present invention is not limited to a contact type inspection probe, and includes a non-contact type inspection probe.

  The measurement unit 5 outputs an inspection signal to the circuit board 10 through the probes 4a and 4b according to the control of the control unit 9, for example, the insulation state (presence of short circuit) of the conductor pattern on the circuit board 10 An electrical inspection is performed to electrically inspect the conduction state (the presence or absence of disconnection). The operation unit 6 includes an inspection start switch (not shown). The storage unit 7 includes reference position information (probing position information Dp indicating a relative position (x coordinate value, y coordinate value) in the circuit board 10) for each probing point Pt defined on the surface of the circuit board 10, and Mark points Pm defined on the surface of the corner of the circuit board 10 (in this example, the circuit board 10 is rectangular, so four points Pm1, Pm2, Pm3, and Pm4: hereinafter referred to as “mark point Pm” unless otherwise specified) And the reference position information (mark position information Dm indicating the relative position (x coordinate value, y coordinate value) in the circuit board 10). In this case, each position information Dp, Dm is determined based on design data such as CAD data used when designing the circuit board 10, and is based on predetermined orthogonal coordinates defined on the circuit board 10. It is expressed by the coordinate value at. The camera 8 captures an image of the circuit board 10 mounted on the mounting table 2, acquires image data Dc of the circuit board 10, and outputs the image data Dc to the control unit 9.

  The control unit 9 is composed of a CPU and also functions as a calculation unit in the present invention, and specifies three mark points Pm from the four mark points Pm1, Pm2, Pm3, and Pm4 based on the probing position information Dp of the probing point Pt. Mark position specifying process to be performed, parameter calculation process to calculate the position conversion parameter, and actual position information for calculating the actual position information Dpr of the probing point based on the calculated position conversion parameter and the probing position information Dp stored in the storage unit 7 An information calculation process and a moving process for moving the probes 4a and 4b to the probing point by performing control on the moving mechanisms 3a and 3b are executed. Further, the control unit 9 controls the operations of the moving mechanisms 3a and 3b and the measuring unit 5.

  Next, the inspection operation for the circuit board 10 of the circuit board inspection apparatus 1 will be described with reference to FIG. It is assumed that the circuit board 10 to be inspected is set in advance on the mounting table 2 as shown in FIG.

  In this state, when an operation on the inspection start switch of the operation unit 6 is performed, the control unit 9 starts an inspection process on the circuit board 10. Specifically, first, the control unit 9 performs probing position information Dp (xpa, ypa) for the probing point Pt (Pta) for probing the probe 4a and probing position information for the probing point Pt (Ptb) for probing the probe 4b. Dp (xpb, ypb) is read from the storage unit 7 (step 51), and then a mark point specifying process is executed to specify mark points corresponding to the probing points Pta and Ptb (step 52).

  In this mark point specifying process, the control unit 9 first calculates the position conversion parameter by comparing the read probing position information Dp with the mark position information Dm of each mark point Pm stored in the storage unit 7. Three mark points Pm to be used for the determination are specified. Specifically, among the four mark points Pm, three mark points Pm that are closer to the probing point Pt (the closest mark point Pm, the next closest mark point Pm, and The next closest mark point Pm) is specified. Thereby, for example, as shown in FIG. 2, when the circuit board 10 is divided into ½ in the width direction (up and down direction in the figure) and the length direction (left and right direction in the figure), respectively. A probing point Pt is included in a region Q1 (hatched region) among the two regions (local regions) Q1, Q2, Q3, Q4 (hereinafter also referred to as “region Q” unless otherwise specified). 3, the mark points Pm 1, Pm 2, and Pm 3 surrounded by the alternate long and short dash line are specified. As shown in FIG. When three mark points Pm2, Pm3, and Pm4 surrounded by a chain line are specified and the probing point Pt is included in the region Q3 (the hatched region), as shown in FIG. Pm3, P 4, three of Pm1 is identified, as shown in FIG. 5, when it contains probing point Pt in the region Q4 (the hatched regions), although three mark points Pm4, Pm1, Pm2 are identified. Thereby, the mark point specifying process is completed.

  Subsequently, as shown in FIG. 6, the control unit 9 executes a parameter calculation process for calculating a position conversion parameter in each region Q including the probing points Pta and Ptb (step 53). This parameter calculation process will be described by taking a probing point Pta for probing the probe 4a as an example. In this process, the control unit 9 firstly measures actual position information Dma related to three specified mark points Pm for the circuit board 10 on the mounting table 2 based on image data Dc as actual position information output from the camera 8. Is identified. In the following, as an example, as shown in FIG. 2, a case where the probing point Pta is included in the region Q1 and the mark points Pm1, Pm2, and Pm3 are specified as the three mark points Pm will be described as an example. In this case, the mark position information Dm of each mark point Pm1, Pm2, Pm3 is (x1, y1), (x2, y2), (x3, y3), respectively, and the mark points Pm1, Pm2, Pm3 are specified. The measured position information Dma is (X1, Y1), (X2, Y2), and (X3, Y3), respectively.

The control unit 9 has the following formula (1) and formula (2):
X = Ax + By + E (1)
Y = Cx + Dy + F (2)
(X1, y1) and (X1, Y1), (x2, y2) and (X2, Y2), (x3, y3) and (X3, Y3) Six position conversion parameters A, B, C, D, E, and F of the above equations (1) and (2) are calculated by solving six equations, and the position conversion for the region Q1 including the probing point Pta is performed. Parameters A1, B1, C1, D1, E1, and F1 are stored in the storage unit 7. Further, the control unit 9 also uses the probing point Ptb for the region Q including the probing point Ptb (as an example, included in the region Q2 shown in FIG. 3) in the same manner as the probing point Pta described above. The position conversion parameters A2, B2, C2, D2, E2, and F2 are calculated and stored in the storage unit 7. Thereby, the parameter calculation process is completed.
X1 = Ax1 + By1 + E
Y1 = Cx1 + Dy1 + F
X2 = Ax2 + By2 + E
Y2 = Cx2 + Dy2 + F
X3 = Ax3 + By3 + E
Y3 = Cx3 + Dy3 + F

  Next, the control unit 9 executes the actual position information calculation process to calculate the actual position information Dpr of the probing point Pt and store it in the storage unit 7 (step 54). In this actual position information calculation process, the control unit 9 reads the calculated parameters A1 to F1 from the storage unit 7, and applies the probe parameters to x and y in the above formulas (1) and (2) to which the parameters A1 to F1 are applied. The actual position information Dpr (Xpa, Xpa) is calculated for the probing point Pta by substituting the probing position information Dp (xpa, ypa) for the probing point Pta for probing 4a and calculating X and Y. Further, the control unit 9 reads the calculated parameters A2 to F2 from the storage unit 7, and probing points for probing the probe 4b to x and y in the above formulas (1) and (2) to which the parameters A2 to F2 are applied. The actual position information Dpr (Xpb, Xpb) is calculated for the probing point Ptb by substituting the probing position information Dp (xpb, ypb) for Ptb and calculating X and Y. Further, the control unit 9 stores the calculated actual position information Dpr in the storage unit 7. Thereby, the actual position information calculation process is completed.

  Subsequently, the control unit 9 executes a moving process to cause the probes 4a and 4b to probe the probing points Pta and Ptb on the circuit board 10, respectively. In this moving process, the control unit 9 first controls the moving mechanism 3a based on the calculated actual position information Dpr (Xpa, Xpa) to move the probe 4a above the probing point Pta, and then moves the probe 4a to the circuit board. By moving the probe 4a by a predetermined distance in 10 directions, the probe 4a is brought into contact with the probing point Pta. Further, the control unit 9 controls the moving mechanism 3b based on the calculated actual position information Dpr (Xpb, Xpb) to move the probe 4b above the probing point Ptb, and then moves the probe 4b toward the circuit board 10 by a predetermined distance. By moving the probe 4b only, the probe 4b is brought into contact with the probing point Ptb. Thereby, the movement process is completed.

  Next, the control unit 9 controls the measurement unit 5 to perform an electrical inspection, and stores the inspection result in the storage unit 7 (step 55). Thereby, the inspection for the pair of probing points Pta and Ptb is completed. The controller 9 determines whether or not the electrical inspection has been completed for all probing points Pt (Pta, Ptb) associated with the probes 4a and 4b stored in the storage unit 7 (step 56). Steps 51 to 56 are repeated, and all electrical inspection processes are completed when electrical inspection is completed for all probing points Pta and Ptb. In step 53, when the position conversion parameters A to F for the region Q including the probing point Pt are already calculated, the position conversion parameters A to F are read from the storage unit 7 and used, and the probing point Pt is used. When the position conversion parameters A to F for the region Q including the number are not yet calculated, the position conversion parameters A to F are calculated and stored in the storage unit 7 according to the procedure described above.

  Thus, in this circuit board inspection apparatus 1, when probing the probes 4a and 4b at the probing points Pta and Ptb on the circuit board 10 mounted on the mounting table 2, the control unit 9 uses each mark. Position conversion parameters A to F are calculated based on the mark position information Dm and the measured position information Dma for the three mark points Pm previously associated with the probing points Pta and Ptb among the points Pm1 to Pm4. The position conversion process using the calculated position conversion parameters A to F is performed on the probing position information Dp for the probing point Pt to calculate the actual position information Dpr for the probing point Pt, and the calculated actual position information Dpr Based on this, the moving mechanism 3b is controlled to bring the probe 4b into contact with the probing point Pt. Therefore, according to this circuit board inspection apparatus 1, a large board can be obtained by associating in advance three mark points Pm close to each probing point Pta, Ptb with each probing point Pta, Ptb. In addition, a probing point Pt for actually probing the probes 4a and 4b even on a circuit board in which the generated distortion is not uniform throughout, such as a circuit board made of an inexpensive material having a large distortion due to expansion / contraction. A local region calculated based on the mark position information Dm and the measured position information Dma of the mark point that is close to (a region defined by three mark points close to the probing point Pt in the circuit board 10) ), The actual position information Dpr of the probing point Pt can be calculated using the position conversion parameters A to F. It results it is possible to reduce an error of the transformation parameters to F, the probe 4a, 4b and can be more accurately contacted to the desired probing point Pt.

  Further, according to the circuit board inspection apparatus 1, the control unit 9 has three mark points Pm (the closest mark points Pm that are closest to the probing point Pt among the mark points Pm1 to Pm4). The next closest mark point Pm and the next closest mark point Pm) are specified, and the three mark points Pm are made to correspond to the probing point Pt, thereby probing the probes 4a and 4b. Since the actual position information Dpr of the probing point Pt can be calculated using the position conversion parameters A to F for the local region closest to the probing point Pt to be corrected, the error of the position conversion parameters A to F is further increased. As a result, the probes 4a and 4b can be brought into contact with the desired probing point Pt even more accurately.

  In addition, this invention is not limited to said structure. As an example, an example in which a total of four mark points Pm are defined at each corner of the rectangular circuit board 10 has been described above. For example, as shown in FIG. The number of mark points Pm can be specified to be five or more, such as defining mark points Pm5 to Pm9. Thus, by further increasing the number of mark points Pm, the area of the region Q when the three mark points closer to the probing point Pt are specified can be defined smaller as shown in FIG. As a result, errors in the position conversion parameters A to F can be further reduced, and as a result, the probes 4a and 4b can be brought into contact with the desired probing point Pt more accurately. Further, when the position conversion parameters A to F are calculated, the error contained in the position conversion parameters A to F can be further reduced by using the least square method.

  Further, the example in which the three mark points Pm corresponding to each probing point Pt are specified prior to the calculation of the position conversion parameters A to F has been described above, but the circuit board 10 is divided into a plurality of regions Q in advance and the regions Q It is also possible to adopt a configuration in which the three mark points Pm for the probing points Pt included in each region Q are associated in advance by defining three mark points Pm in advance for each. According to this configuration, the time required for inspection can be shortened by the amount of time and effort required to specify the three mark points Pm corresponding to each probing point Pt. Further, since the position conversion parameters A to F corresponding to the three specified mark points Pm can be obtained in advance prior to the inspection, the calculation of the position conversion parameters A to F for every probing position is omitted. be able to. Further, the circuit board 10 may be a multi-sided circuit board configured by combining a plurality of boards as a single circuit board, or may be a single-sided circuit board. In this case, in the case of a multi-sided circuit board, the configuration is not limited to specifying only the mark points in one circuit board, but three of a plurality of mark points defined on two or more circuit boards are specified. You can also Further, the example in which each mark point Pm is defined at the corner of the circuit board 10 has been described above as a preferred example. However, the position of each mark point Pm can be arbitrarily defined, for example, a site where a large distortion occurs locally. Can be defined inside the circuit board 10 so as to surround the portion of the circuit board 10 that is known in advance.

  Further, of the plurality of mark points Pm, the probing point Pt is closest to the probing point Pt, next to the probing point Pt, and next to the probing point Pt. A preferred example of calculating and using the position conversion parameters A to F for the local region closest to the probing point Pt by associating the mark point Pm has been described above, but other than the closest local region Three mark points Pm that define a local region can also be made to correspond. For example, the probing points Pt included in the region Q shown in FIG. 7 are associated with three mark points Pm1, Pm5, and Pm8, thereby probing defined by these mark points Pm1, Pm5, and Pm8. It is preferable to calculate and use the position conversion parameters A to F for the local region closest to the point Pt (the region surrounded by the alternate long and short dash line), but the three mark points Pm close to the probing point Pt may be used. For example, the probing is performed when the circuit board 10 shown in the figure is divided into two in the vertical direction (with straight lines including the mark points Pm6 and Pm8) or in the horizontal direction (with straight lines including the mark points Pm5 and Pm7). Any three mark points Pm included in the same area as the point Pt can be made to correspond to the probing point Pt. For example, three mark points Pm1, Pm2, Pm8, three mark points Pm1, Pm5, Pm9 included in the same region when the circuit board 10 is divided into two in the vertical direction with respect to the probing point Pt shown in FIG. Alternatively, three mark points Pm1, Pm2, Pm9, etc. can be made to correspond.

  Similarly, when the circuit board 10 is divided into two in the horizontal direction, three mark points Pm1, Pm8, Pm9, three mark points Pm1, Pm4, Pm9, and three mark points Pm1, Pm4 included in the same region. Pm5 or the like can also be used. Thus, even if the other three mark points Pm close to the probing point Pt are associated with the probing point Pt, one set of position conversion parameters A to F for the entire region of the circuit board 10 is calculated. Compared with the configuration in which the actual position information Dpr for all probing points Pt in the circuit board 10 is calculated using the position conversion parameters A to F, the error of the position conversion parameters A to F can be made sufficiently small. As a result, the probing accuracy of the probes 4a and 4b can be sufficiently improved.

1 is a configuration diagram showing a configuration of a circuit board inspection device 1. FIG. It is a top view of the circuit board 10 which shows the positional relationship of each mark point Pm1-Pm4 and each area | region Q1-Q4, and the area | region Q1 in which the probing point Pt is contained. It is a top view of the circuit board 10 which shows the positional relationship of each mark point Pm1-Pm4 and each area | region Q1-Q4, and the area | region Q2 in which the probing point Pt is contained. It is a top view of the circuit board 10 which shows the positional relationship of each mark point Pm1-Pm4 and each area | region Q1-Q4, and the area | region Q3 where the probing point Pt is contained. It is a top view of the circuit board 10 which shows the positional relationship of each mark point Pm1-Pm4 and each area | region Q1-Q4, and the area | region Q4 where the probing point Pt is contained. 4 is a flowchart for explaining inspection processing by the circuit board inspection apparatus 1; It is a top view of the circuit board 10 which shows the positional relationship of each mark point Pm1-Pm9 and the area | region Q where the probing point Pt is contained.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board inspection apparatus 3a, 3b Moving mechanism 4a, 4b Probe 5 Measuring part 7 Storage part 8 Camera 9 Control part 10 Circuit board A-F Position conversion parameter Dma Actual position information Dpr Actual position information Pm1-Pm4 Mark point Pt Probing point

Claims (2)

A storage unit for storing reference position information about four or more mark points defined on the circuit board and a probing point for probing the probe;
A camera for acquiring measured position information about each mark point on the circuit board disposed at an inspection position;
When probing the probe to the probing point on the circuit board disposed at the inspection position, the three mark points previously associated with the probing point among the mark points. A position conversion parameter is calculated based on the reference position information and the measured position information, and a position conversion process using the calculated position conversion parameter is performed on the reference position information for the probing point, and the probing point is calculated. A circuit board inspection apparatus comprising a calculation unit that calculates actual position information.   The circuit board inspection apparatus according to claim 1, wherein the arithmetic unit associates three mark points closer to the probing point among the mark points as the three mark points.

Images