JP5382005B2 - Paste application method - Google Patents

Description

  The present invention relates to a paste application method for applying a paste for mounting an electronic component on a workpiece such as a substrate.

  As a mounting method for mounting an electronic component on a workpiece such as a substrate, a method is known in which a paste is applied to a predetermined position of a workpiece by a coating head, and the electronic component is mounted on the paste applied by the mounting head (Patent Literature). 1). The application head has a built-in syringe for storing the paste. By applying a discharge pressure such as air pressure to the paste in the syringe, the paste is discharged from the lower end of the nozzle provided in the lower part of the application target. It is designed to be applied to.

JP-A-11-28406

  In the above method, first, it is required that the amount of paste applied by being discharged from the nozzle of the coating head is an appropriate amount. Therefore, conventionally, it is known to adjust the application amount to an appropriate amount by adjusting the discharge pressure such as air pressure applied to the paste stored in the syringe of the application head.

  Second, it is required that the paste application position accuracy can be maintained high. The paste application position accuracy greatly depends on the position accuracy of the center position of the syringe or the nozzle that discharges the paste (in general, the center position of the syringe is the same as the center position of the nozzle). In addition, this center position accuracy is also distorted due to the change over time of the paste application equipment including the application head due to the influence of heat generated by the linear motor employed in the movement mechanism of the application head. Therefore, it is required that the inspection of the paste application position be performed easily and accurately at any time. However, a paste coating method that can satisfy such requirements has not yet been proposed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paste application method that can easily and accurately perform an inspection of a paste application position.

  The present invention is a paste application method using an application head that has a paste storage part and discharges the paste from a nozzle by a discharge pressure applied to the paste storage part and applies the paste to a workpiece. Based on the recognition result of the first recognition process, the recognition process for recognizing the paste applied in the first shape to the disposal stage by the recognition means, and the recognition result of the recognition process A step in which the control device calculates the discharge pressure, a determination step in which the control device determines whether the calculated discharge pressure is within a specified range, and a determination result in the determination step is No. Adjusting the discharge pressure and repeating the first discarding step and the recognition step until the determination result is Yes, and if the determination result is Yes, the coating process is repeated. A second discarding step in which the paste is applied to the discarding stage in the second shape by the head, and the paste applied in the second shape to the discarding stage is recognized by the recognition means, and the position from the target position A misregistration correction value calculation step of calculating a deviation amount as a correction value by the control device; and a step of correcting the paste application position of the application head by the correction value and applying the paste to the workpiece.

  In the present invention, the paste is applied in the first shape to the discarding stage, and this is recognized by the recognition means to judge whether the discharge pressure is good or not, and if the determination result is Yes (ie, the discharge pressure is good). If appropriate, apply paste in the second shape to the abandoned stage, recognize this paste by the recognition means, and calculate the amount of displacement from the target position as a correction value. The paste application position of the application head is corrected by the corrected value, and the paste can be applied to the correct position of the workpiece. In particular, since the second shape paste whose discharge pressure is appropriately adjusted is recognized, the second shape does not become unstable due to excessive or insufficient discharge pressure. As a result, since the second shape is stabilized, the center position of the second shape can be accurately calculated by image analysis, and a more accurate correction value can be obtained. Can be corrected.

  In addition, the paste application position is likely to be distorted due to changes over time of the paste application equipment including the application head due to the influence of heat generated by the linear motor employed in the application head moving mechanism. According to this, since the inspection for updating the correction value of the paste application position can be executed at an arbitrary timing, the paste application position accuracy can be maintained with high accuracy.

1 is an overall view of an electronic component mounting apparatus according to an embodiment of the present invention. The fragmentary top view of the substrate holding stage in one embodiment of the present invention The top view of the paste of the 1st shape apply | coated to the discard stage in one embodiment of this invention The top view of the paste of the 2nd shape apply | coated to the discarding stage in one embodiment of this invention The flowchart of operation | movement of the syringe center position correction value detection in one embodiment of this invention The flowchart of the operation | movement which mounts the electronic component in one embodiment of this invention on a board | substrate

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an electronic component mounting apparatus including a paste application apparatus.

  A substrate 1 that is a workpiece that is an object of paste application and electronic component mounting is positioned and held on a table unit 10. The table unit 10 is a movable table, and is configured by stacking an X-axis table 11 and a Y-axis table 12 and installing a substrate holding stage 13 on the Y-axis table 12. The substrate 1 is held on the substrate holding stage 13. At the side of the substrate holding stage 13, a throwing stage 14 is provided. The discard stage 14 may be provided on a side portion on the substrate holding stage 13. An electronic component supply unit 15 is provided on the side of the table unit 10. An electronic component P is provided on the electronic component supply unit 15.

  The application head 20 includes a syringe 21 that is a paste reservoir, and a nozzle 22 that discharges the paste stored in the syringe 21 at a lower portion thereof. The paste discharge mechanism 24 and the coating head moving mechanism 25 of the coating head 20 are controlled by a control device 26. In response to a command from the control device 26, the paste discharge mechanism 24 applies a discharge pressure to the paste liquid level in the syringe 21, whereby the paste is discharged from the nozzle 22. The amount of paste applied is adjusted by adjusting the magnitude of the discharge pressure.

  The coating head moving mechanism 25 is composed of a moving mechanism using a linear motor such as an X-axis table, a Y-axis table, or a Z-axis table as a drive source, and moves the coating head 20 in the X, Y, and Z directions according to commands from the control device 26. The paste discharged from the nozzle 22 is applied to a predetermined position on the substrate 1.

  The mounting head 30 includes a nozzle 31 that vacuum-sucks and holds the electronic component P at its lower end, and a camera as a recognition means for recognizing a paste applied to a predetermined portion of the substrate 1 or the throwing stage 14. 32. The mounting head moving mechanism 33 includes a moving mechanism using a linear motor such as an X-axis table, a Y-axis table, and a Z-axis table as a drive source. The mounting head 30 is moved in the X, Y, and Z directions according to commands from the control device 26. The electronic component P of the electronic component supply unit 15 is picked up and mounted at a predetermined position on the substrate 1.

  In FIG. 2, the discarding stage 14 has a first area 141 and a second area 142. The first area 141 is a paste discharge pressure inspection area, and the second area 142 is a syringe center position inspection area.

  Next, a syringe center position correction value detection method will be described with reference to the flowchart of FIG. The flowchart of FIG. 5 is composed of ST1 to ST7, among which ST1 to ST4 are steps for setting the discharge pressure to a predetermined pressure (appropriate pressure for paste application), and ST5 to ST7 are discharge pressures. Is a step of obtaining a positional deviation amount (correction value) from the center position of the syringe 21 and its target position after the pressure is set to a predetermined pressure. Note that the center positions of the syringe 21 and the nozzle 22 can be regarded as the same.

  First, in ST1, the coating head 20 is moved onto the first area 141 (FIG. 2), where the paste is applied in a first shape by a predetermined drawing procedure (first discarding step). FIG. 3 shows an example of this drawing. In this example, the X shape is drawn with the paste 23 in a square (area S1) with one side of Lmm, but other shapes may be used as long as the discharge pressure can be easily calculated. Next, in ST2, the coating head 20 is moved away from the first area 141, the camera 32 of the mounting head 30 is moved to the first area 141, and the drawn paste 23 is recognized as an image. The control device 26 is based on the recognition result. The discharge pressure is calculated. The camera 32 is a CCD camera, and the control device 26 calculates a drawn x-shaped area S2 from the captured image. Then, the discharge pressure is calculated from the ratio between the area S1 and the area S2.

  Next, the controller 26 determines whether or not the discharge pressure calculated in step ST3 is within a specified range. If No (defective), the discharge pressure is adjusted in ST4, and steps ST1 to ST3 are performed. repeat. If the determination result in ST3 is Yes (good), the discharge pressure adjustment operation ends, and the process proceeds to steps ST5 and subsequent steps. It is known that the ratio of the areas as described above is calculated and an appropriate discharge pressure is obtained from the calculated result, and the second shape is set to a shape that facilitates adjustment of the discharge pressure.

In step ST5, the paste is applied to the second area 142 in a second shape (in this example, a point shape) by the application head 20 whose discharge pressure is adjusted to an appropriate pressure. FIG. 4 shows the paste 23 applied in a dot shape. The second shape is a shape in which the center position is easily obtained by image analysis such as a point shape. Next, the coating head 20 is moved away from the second area 142, the camera 32 of the mounting head 30 is moved above the point-shaped paste 23, the paste 23 is image-recognized, and the control device 26 is based on the image recognition result. Calculates the center position (X, Y coordinate position) O ₂ of the point-shaped paste 23 (ST6).

Then, in ST7, the central position O ₁ on the control data of the syringe 21 when the center position O ₂ and paste calculated point shape of the paste 23 was _applied, i.e. compares the target position, the position deviation from the target position The amount, that is, the amount of displacement between both positions is acquired as a correction value (Δx, Δy). This completes the syringe center position correction value detection operation. The center position of the syringe (nozzle) can be regarded as the paste application position.

  Prior to acquiring the correction values (Δx, Δy) in ST5 to ST7, the discharge pressure is adjusted in ST1 to ST4 for the following reason. That is, when the paste is applied in the second shape (point shape) with an appropriate discharge pressure, the paste is applied around the center of the syringe (nozzle), so the center of the applied paste is regarded as the center of the syringe. be able to. Of course, ST5 to ST7 may be repeated a plurality of times, and the average value may be used as the correction value.

  However, when the discharge pressure is excessive, the paste applied in a spot shape spreads greatly, but does not necessarily spread in a circular shape around the center of the nozzle, but tends to spread in a deformed shape. Therefore, even if the center of the paste that is deformed and spreads out is found, this includes a big madness. The same is true when the discharge pressure is too low, and the applied paste does not necessarily shrink in a circular shape centered around the center of the nozzle (syringe), but easily deforms and shrinks in an irregular shape. The same tendency as the above-mentioned excessive case is likely to occur. For the above reasons, after adjusting the discharge pressure to an appropriate pressure (discharge pressure that makes it easy to find the correct center position of the syringe from the applied paste) in ST1 to ST4, ST5 to ST7 are executed to obtain the correction value. It is.

  Next, the positional deviation amount (Δx, Δy) from the target position of the center position of the syringe 21 obtained in this way is used as the correction amount of the paste application device at the time of mounting the electronic component to the electronic component supply unit 15. A method of mounting the provided electronic component P at a predetermined coordinate position of the substrate 1 will be described with reference to the flowchart of FIG.

  First, the substrate 1 is positioned on the table unit 10 (ST11). Next, it is determined whether or not it is necessary to update the position correction value of the syringe 21 (ST12). If Yes, the above-described flowchart of FIG. 5 is executed to detect the correction value (Δx, Δy) of the syringe center position (ST13).

  The center position or correction value of the syringe 21 is detected in the flowchart of FIG. 5, but the center position of the syringe 21 is influenced by the heat generated by the linear motor employed in the application head moving mechanism as described above. Due to the time-dependent change of the paste application equipment caused by the Therefore, it is necessary to appropriately execute steps ST12 and ST13 during mounting of the electronic component. These ST12 and 13 may be executed every time the coating head 20 performs paste application a predetermined number of times (for example, 10 times), or may be executed every predetermined time (for example, once every 10 minutes). The frequency and timing of execution can be freely determined.

  Next, in ST14, a paste is applied onto the substrate 1 by the coating head 20, and in ST15, the mounting head 30 picks up the electronic component P of the electronic component supply unit 15, and in ST16, the electronic component P is placed on the paste applied in ST14. Is implemented. This mounting operation is repeated until the mounting of all electronic components is completed (ST17).

  As described above, the present invention applies the paste in the first shape to the discard stage, recognizes this by the recognition means, determines whether the discharge pressure is good, and if the determination result is Yes (i.e., good) When the discharge pressure is appropriate), the paste is applied in the second shape to the discarding stage, the paste is recognized by the recognition means, and the amount of displacement from the target position is calculated as a correction value. Thus, the paste application position of the application head can be corrected with the correction value obtained in this way, and the paste can be applied to the correct position of the workpiece. In particular, since the second shape paste whose discharge pressure is appropriately adjusted is recognized, the second shape does not become unstable due to excessive or insufficient discharge pressure. As a result, since the second shape is stabilized, the center position of the second shape can be accurately calculated by image analysis, and a more accurate correction value can be obtained. Can be corrected.

  In the embodiment of the present invention, the camera 32 as the recognition unit is configured to be included in the mounting head 30, but the camera 32 as the recognition unit is fixed above the table unit 10 for recognition. The table unit 10 may be moved in the X direction and the Y direction so that the paste applied on the discard stage 14 is below the camera 32.

  According to the present invention, the correction value of the paste application position can be obtained, the paste can be applied to the correct position of the workpiece by the application head, and the inspection for updating the correction value of the paste application position can be performed at an arbitrary timing. Since it can be performed, the paste application position accuracy can be maintained with high accuracy, which is particularly useful in the field of electronic component mounting.

DESCRIPTION OF SYMBOLS 1 Board | substrate 14 Discarding stage 20 Application | coating head 21 Syringe 22 Nozzle 23 Paste 26 Control apparatus 30 Mounting head 31 Nozzle 32 Camera

Claims (2)

It has a paste reservoir, and is a method of applying a paste by an application head that discharges paste from a nozzle by a discharge pressure applied to the paste reservoir and applies it to a workpiece.
A first discarding step of applying a paste in a first shape to a discarding stage by the application head;
A recognition step of recognizing the paste applied in the first shape on the discarding stage by the recognition means;
A control device calculating the discharge pressure based on a recognition result of the recognition step;
A determination step in which the control device determines whether or not the calculated discharge pressure is within a specified range; and
If the determination result of the determination step is No, the step of adjusting the discharge pressure and repeating the first discarding step and the recognition step until the determination result is Yes,
If the determination result is Yes, a second discarding step of applying paste to the discarding stage in a second shape by the application head;
A step of calculating a misalignment correction value by recognizing the paste applied in the second shape on the discard stage by a recognition unit, and calculating a misalignment amount from the target position as a correction value by a control device;
Correcting the paste application position of the application head by the correction value and applying the paste to the workpiece;
A paste application method comprising:   The paste application method according to claim 1, wherein the first shape is an X shape and the second shape is a point shape.

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