JP2010093212A - Surface mounting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately correct a mounting displacement of an electronic component caused by inclination of an attraction nozzle mounted on a mounting head. <P>SOLUTION: A substrate recognition camera recognizes a mark on an arbitrary straight line in a jig substrate where a plurality marks are arranged and formed on straight lines arranged longitudinally and laterally at predetermined intervals, and stores recognition shift amounts in X direction and in Y direction of each mark. There are extracted marks of respective 2 points where differences of the recognition shift amounts are maximum in respective X and Y directions, and an electronic component is actually mounted at mounting scheduling positions respectively set in the vicinity of the marks of the 4 points. The mark corresponding to each electronic component is captured by the substrate recognition camera in the same field, and acquires shift amounts of mounting the electronic component referring the mark from an image. Further, obtaining the maximum difference value of recognition shift amounts in X direction and in Y direction with respect to the marks of respective 2 points by the substrate recognition camera, and taking as a coefficient a ratio between the foregoing difference and the difference of the corresponding mounting shift amount, the coefficient is multiplied by each mark recognition shift amount on the foregoing straight line to estimate the mounting shift amount. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface mounting method, and more particularly to a surface mounting method suitable for application when improving the mounting accuracy of electronic components on a substrate.

  In general, in a surface mounting apparatus, an electronic component sucked and held by a suction nozzle mounted on a mounting head is moved by an XY robot to a target position on a substrate positioned in a predetermined mounting area. It is carried out.

  In this way, in an XY robot that moves the mounting head in the XY direction, in addition to distortion and deflection of the X-axis beam that guides the mounting head in the X direction, distortion of the Y-axis guide rail that guides the X beam in the Y direction. The collapse of linearity due to bending or bending is an error factor that prevents the electronic components from being uniformly mounted on the entire surface of the substrate.

  As a conventional technique for correcting an error due to such factors by the surface mounting apparatus itself, for example, in Patent Document 1, a mounting head is provided with a dummy substrate having a plurality of marks positioned at predetermined positions. The image is picked up by a substrate recognition camera such as a CCD camera for detecting the substrate mark, and the error amount of the XY robot is obtained from the error between the mark position on the picked-up image and the theoretical mark position, and is used as the correction amount. A method has been proposed.

  In Patent Document 2, a glass jig substrate provided with a plurality of marks is positioned over the entire mounting region, and electronic components are actually mounted on the glass jig substrate using a mounting head. A method has been proposed in which a mounted electronic component and a mark are simultaneously imaged by a substrate recognition camera to acquire a correction amount.

  However, the distortion and deflection of the XY robot usually do not only cause a planar error in the XY direction. Ideally, it is desirable that the suction nozzle mounted on the mounting head always maintain a perpendicular relationship with respect to the substrate plane at any XY coordinate. In some cases, the vertical relationship with respect to the substrate plane is distorted and tilted.

  If such a tilt component from the vertical direction exists in the suction nozzle, the theoretical deviation from the target coordinates observed by the board recognition camera and the mounting deviation when the electronic component is actually mounted on the target coordinates Therefore, if correction is performed only by the amount of mark deviation observed by the substrate recognition camera as in Patent Document 1, high-accuracy correction for the mounting position cannot be guaranteed. .

  Therefore, as in Patent Document 2, an electronic component is actually mounted on the entire surface of the glass jig substrate, and the mounted electronic component is observed with a substrate recognition camera, thereby obtaining a highly accurate correction amount for the mounting position. A method is needed.

JP 2001-136000 A JP 2001-244696 A

  However, in the method disclosed in Patent Document 2, it is necessary to actually mount the electronic components on the entire surface of the glass jig substrate and sequentially image all of the electronic components with the substrate recognition camera. There is a problem that it is necessary to prepare a large number of electronic components to be used and it takes time to acquire data.

  The present invention has been made to solve the above-mentioned conventional problems, and a large amount of electronic components is prepared for the amount of mounting position displacement of electronic components including errors caused by the inclination of the suction nozzle mounted on the mounting head. Accordingly, it is an object of the present invention to provide a surface mounting method capable of acquiring correction data in a short time and realizing high-precision correction.

  The present invention moves the mounting head having a substrate recognition camera that images the lower side together with a nozzle movable portion to which a suction nozzle can be attached at the lower end, and positions the electronic component sucked by the suction nozzle in the mounting region. In a surface mounting method for mounting on a substrate, a jig substrate in which a plurality of marks are arranged on a straight line at predetermined intervals in the vertical and horizontal directions is positioned on the mounting region, and is on an arbitrary straight line. The step of recognizing the mark by the substrate recognition camera and storing the recognized deviation amount in the X direction and the Y direction obtained for each mark, and the difference between the obtained recognition deviation amounts for each of the X direction and the Y direction are maximized. A total of four marks of two points are extracted, electronic components are actually mounted at the respective mounting positions set in the vicinity of the four marks, and corresponding to each mounted electronic component. Each of the marks is picked up by the board recognition camera within the same field of view, and a mounting deviation amount of the electronic component with reference to the mark is obtained based on the picked up images, and each of the two obtained in the X direction and the Y direction. A step of obtaining, as a coefficient, a ratio between a maximum difference in recognition deviation amount relating to a point mark and a corresponding difference in mounting deviation amount, and the obtained coefficient is stored for each mark on the straight line. By multiplying the amount of deviation and estimating the amount of mounting deviation on the straight line, and correcting the mounting position based on the estimated amount of mounting deviation and mounting the electronic component on the board, The problem is solved.

  In the present invention, the arbitrary straight line may be a straight line in each of the X direction and the Y direction.

  According to the present invention, a recognition deviation amount is obtained by a substrate recognition camera for one row of marks (arbitrary straight line marks) arranged on a lattice on a jig substrate, and the four marks among them are obtained. Only the electronic component is actually mounted, and the coefficient for the column is obtained based only on the mounting deviation amount, and the other marks are obtained by multiplying the recognition deviation amount by the coefficient. It is possible to estimate the mounting displacement amount with high accuracy in consideration of the inclination of the nozzle axis for all the marks. Thus, by obtaining the mounting displacement amount for a mark on one straight line, for example, a highly accurate correction for the corresponding position in the X direction can be realized, and the mark on a straight line orthogonal to the straight line is processed in the same manner. , High-accuracy correction for the corresponding position in the Y direction can be realized. Therefore, compared to the case where the electronic components are actually mounted on all the marks and the correction amount for each mark is acquired, the number of components can be reduced, so that data can be acquired in a short time. , High-precision correction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic plan view schematically showing a surface mounting apparatus according to an embodiment of the present invention.

  In this surface mounting apparatus, the mounting head 10 is guided and moved in the X direction (lateral direction) by the X axis beam 12 constituting the XY robot, and is integrated with the X axis beam 12 by the left and right Y axis guide rails 14. It is guided and moved in the Y direction (vertical direction).

  Further, in this surface mounting apparatus, the electronic components respectively supplied to the feeder composed of the front-side component supply unit 16 and the rear-side component supply unit 18 are held by the mounting head 10 and then positioned in the mounting region. Mount at the target position above.

  FIG. 2 shows an enlarged view of the mounting head 10 in FIG. 1 as viewed from the front. The mounting head 10 is provided with a plurality of head movable parts 20 as shown in the figure, and each of the electronic parts P is sucked and held by a suction nozzle 22 attached to the lower end of the mounting head 10 or released. An electromagnetic valve, a Z-axis servo motor for moving the suction nozzle 22 up and down, and a θ-axis servo motor for rotating the suction nozzle 22 are provided.

  Further, the mounting head 10 is provided with a component recognition device 24 having a function of detecting a shift of the component suction position with respect to the center of the nozzle based on a light shielding width when the laser is irradiated.

  The mounting head 10 is provided with a substrate recognition camera 26 formed of a CCD camera, and can recognize a reference mark (not shown) on the substrate S positioned by the substrate recognition camera 26. A mark on a jig substrate, which will be described later, can be recognized.

  Further, in the mounting head 10, the electronic component P is sucked from the front-side component supply unit 16 and the rear-side component supply unit 18, and is picked up by the component recognition device 24 while moving to the target mounting position of the substrate S. It is possible to recognize a deviation amount and an angular deviation of the electronic component P from the center of the nozzle, and the mounting head 10 corrects the deviation amounts of XY and θ recognized during the movement by the nozzle movable unit 20, so The electronic component P is mounted at the target position.

  FIG. 3 is a plan view schematically showing a jig substrate 30 used in the present embodiment. The jig substrate 30 is a plurality of glass substrates that can be recognized by the substrate recognition camera 26 vertically and horizontally. The marks M are arranged on a straight line with a constant interval.

  In the present embodiment, the jig substrate 30 shown in FIG. 3 is placed in place of the substrate S in the mounting area where the substrate S shown in FIG. Position.

  An arbitrary horizontal (or vertical) line M (on a straight line) of the marks M arranged on the jig substrate 30 is recognized by the substrate recognition camera 26, and a camera corresponding to each theoretical coordinate. Is stored as a correction value, and the difference between the two points where the difference in the X direction deviation amount is the maximum and the difference in the Y direction deviation amount. Extract a total of four marks, two of which are the maximum.

  Next, the electronic component P is actually mounted in the vicinity of the four extracted marks, and the amount of deviation from the theoretical coordinates of the mounted electronic component P is the same between the electronic component P and the mark M by the board recognition camera 26. Recognize by imaging in the field of view. Originally, the electronic component P should be mounted with the mark center at the target position. However, when mounted on the mark M, the positional relationship between the mark M and the mounted electronic component P can be grasped on the image. Since it cannot be performed, it is mounted on the theoretical coordinates (scheduled mounting position) in the vicinity of the mark M which is in a positional relationship with respect to the target mark M by a certain distance.

  In this way, the mounting displacement amount when the electronic component P is mounted on the coordinates near the mark M where the difference in the recognition displacement amount by the substrate recognition camera 26 is maximized is obtained, and as shown in the following formula (1) (mounting) The ratio of the difference in deviation amount / the maximum difference in recognition deviation amount is calculated as a coefficient, and the calculated coefficient is multiplied by each recognition deviation amount by the substrate recognition camera 26 on a straight line (or vertical line). Thus, the mounting correction amount in one horizontal row (or one vertical row) is estimated from the recognition results for the four representative marks, and is reflected in the correction when mounting the electronic component P on the board during production.

  Hereinafter, the present embodiment will be described in detail with specific examples.

  Here, a method for calculating a correction amount for a horizontal line will be described with the X direction as a representative.

  First, with respect to a method for obtaining correction data, an arbitrary horizontal row of marks on the jig substrate 30 shown in FIG. 3 is image-recognized by the substrate recognition camera 26, and the n-th theoretical coordinate obtained from each recognition result is obtained. Recognition deviation amount: (dXccd [0], dYccd [0]), (dXccd [1], dYccd [1]) .. (dXccd [n-1], dYccd [n-1]) It is stored as a correction value for deviation. Note that the subscript ccd of each deviation amount means that the substrate recognition camera 26 recognizes only the mark M.

  FIG. 4 schematically shows a mark recognition image. When the mounting head 10 is moved and stopped by the XY robot so that the center (the ccd recognition center in the figure) of the substrate recognition camera 26 coincides with the center (theoretical coordinates) of one mark M, there is a difference between the centers. This is the amount of recognition deviation referred to here.

  Next, from the stored n shift amounts, the mark M most shifted to the + side and the mark M most shifted to the − side are extracted in the X direction and the Y direction, respectively. FIG. 5 shows a graph image of the relationship between the recognition deviation amount and the maximum value and the minimum value of the mark M in a row in the X direction, taking the Y direction as an example. Although illustration is omitted, the amount of deviation in the X direction is similarly obtained for the mark M in the same row.

  As a result, a total of four marks M, that is, two points (dXccdMax, dXccdMin) where the difference in recognition deviation amount is maximum in the X direction and two points (dYccdMax, dYccdMin) where the difference in recognition deviation amount is maximum in the Y direction. Will be extracted. In FIG. 5, only the Y direction is shown.

  With respect to the four marks M extracted by the above method, the electronic component P is actually mounted at a planned mounting position (theoretical coordinates) separated by a certain distance that the board recognition camera 26 can image within the same field of view. Recognizes the distance from the center of each mark M to the center of the mounted electronic component P by the board recognition camera 26, and the actual mounting coordinates (scheduled mounting position of (X, Y) from the mark center) and actually The deviation amount (X ′, Y ′) from the position where the electronic component P is mounted (the actual mounting position of (X + X ′, Y + Y ′) from the mark center) is acquired. An image of component recognition for one mark M in this case is schematically shown in FIG.

  From the obtained deviation amounts, the X direction mounting deviation amounts: dXheadMax and dXheadMin corresponding to X ′ from the two point recognition results for the X direction correspond to Y ′ from the two point recognition results for the Y direction. Y direction mounting deviation amount: dYheadMax and dYheadMin are stored. FIG. 5 also shows a graph image of the mounting deviation amount with reference to the theoretical coordinates of the mark center taking the Y direction as an example.

  Next, a method for using the acquired correction data is described. The substrate recognition camera uses the result of a total of four points each consisting of two points maximum and minimum in the X and Y directions extracted by the above method. The coefficient Ky is obtained by calculating the ratio between the maximum difference in the recognition deviation amount due to No. 26 and the difference in the mounting deviation amount corresponding to these two points by the following equation.

    Ky = (dYheadMax−dYheadMin) / (dYccdMax−dYccdMin) (1)

  Then, the calculated coefficient Ky is first multiplied by the amount of deviation from the n theoretical coordinates stored as data for one horizontal row, thereby calculating a correction value for one horizontal row with respect to the mounting deviation amount. FIG. 7 shows a graph image of the shift amount corresponding to FIG. 5 calculated using the Y direction as an example. Here, for the sake of simplification, the method for one nozzle movable part has been described, but the coefficients need to be obtained for the number of nozzle movable parts 20 included in the surface mounting apparatus.

  Further, if the same method is applied to marks M in an arbitrary vertical line (on a straight line) in the Y direction of the jig substrate, a similar correction value for the Y direction can be obtained.

  Therefore, the mounting position of the electronic component P with respect to the entire mounting area can be accurately corrected by obtaining the coefficients in the same manner on any one straight line in the X direction and the Y direction.

  In addition, since the mounting deviation amount is obtained only from the mark having the largest difference in recognition deviation amount, the coefficient calculation accuracy can be improved.

  As described above in detail, according to the present embodiment, the following effects can be obtained.

(1) By obtaining two types of displacements of recognition by the substrate recognition camera 26 and mounting displacements due to actual mounting with respect to torsion and deflection of the X-axis beam 12, displacements by the XY robot and tilting of the nozzle movable part are obtained. It is possible to correctly correct the difference between the two and the deviation amount due to (tilt with respect to the vertical direction).

(2) The amount of deviation due to mounting corresponds to the maximum value of the difference in recognition deviation amount by the board recognition camera 26 by mounting the electronic component P only at the point where the difference in recognition deviation amount by the board recognition camera 26 is maximized. By obtaining the ratio of difference in mounting deviation as a coefficient and multiplying it by other recognized deviation amount on a straight line, a mechanism for estimating the deviation amount due to mounting in the straight line direction is provided. The number of parts used for mounting can be reduced, and therefore the time for acquiring correction data can be reduced.

1 is a schematic plan view schematically showing a surface mounting apparatus according to an embodiment of the present invention. The schematic front view which shows typically the mounting head with which the surface mounting apparatus of this embodiment is provided. The top view which shows typically the jig | tool board | substrate applied to this embodiment. Explanatory drawing showing the image of mark recognition by the board recognition camera Explanatory drawing which shows the image of the relationship between the mark arranged on the straight line and the amount of recognition deviation by the substrate recognition camera Explanatory drawing which shows the image image which recognizes the actual mounted component and the mark on the same image by the board recognition camera Explanatory drawing which shows the estimation image by the coefficient of deviation amount of the mounting position of electronic parts

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mount head 12 ... X-axis beam 14 ... Y-axis guide rail 16 ... Front side component supply part 18 ... Rear side component supply part 20 ... Head movable part 22 ... Adsorption nozzle 24 ... Component recognition apparatus 26 ... Board recognition camera 30 ... Jig board M ... Mark P ... Electronic component S ... Board

Claims (2)

A mounting head having a substrate recognition camera that images the lower side is moved XY together with a nozzle movable portion to which a suction nozzle can be mounted at the lower end, and the electronic component sucked by the suction nozzle is positioned on the substrate that is positioned in the mounting region. In the surface mounting method to be mounted on
With a jig substrate in which a plurality of marks are arranged on a straight line at predetermined intervals in the vertical and horizontal directions, a mark on an arbitrary straight line is recognized by the substrate recognition camera while being positioned in the mounting area. Storing the obtained recognition deviation amount in the X and Y directions;
A total of four marks are extracted, each having two points where the difference in the amount of recognition deviation obtained is maximum in each of the X and Y directions, and the electrons are actually placed at the planned mounting positions set in the vicinity of the four marks. In addition to mounting components, marks corresponding to each mounted electronic component are captured by the substrate recognition camera within the same field of view, and the mounting displacement amount of the electronic component with reference to the mark is acquired based on the captured image Steps,
Obtaining as a coefficient the ratio between the maximum difference between the recognized deviation amounts for the two marks acquired in the X direction and the Y direction and the corresponding difference between the mounting deviation amounts;
Multiplying the obtained coefficient by the recognized deviation amount stored for each mark on the straight line to estimate the mounting deviation amount on the straight line;
And mounting the electronic component on the substrate by correcting the mounting position based on the estimated mounting deviation amount.   The surface mounting method according to claim 1, wherein the arbitrary straight line is a straight line in each of the X direction and the Y direction.

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