Surface mounting machine

Abstract

To reduce tact loss by shortening the measuring time of the warpage of a substrate.SOLUTION: A surface mounting machine 10 for mounting a component E on a substrate PX includes a head unit 33, a measuring device 47 which is attached to the head unit 33 and measures a warpage amount of the entire substrate by measuring surface heights of a plurality of measurement points P on the substrate, and a control unit 100. The measuring device 47 is a laser measuring instrument that measures the surface height by irradiating a measurement point P of the substrate PX with a laser beam. The control part 100 reduces the number N of measuring points by the laser beam as the maximum warping amount Wmax of the substrate PX is smaller.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a technique for shortening the time required to measure the amount of warpage of an entire substrate. [Background technology]

[0002] A surface mounter is a device that mounts components onto a board. The surface mounter may adjust the amount of component pressing into the board depending on the warpage of the board. Patent Document 1 discloses this type of technology. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4185960 Summary of the Invention [Problem to be solved by the invention]

[0004] To measure the amount of warpage of the entire substrate, it is necessary to measure the surface height of the substrate at multiple locations (multiple measurement points), which takes time. An object of the present invention is to reduce the time required to measure the amount of warpage of the entire substrate. [Means for solving the problem]

[0005] (1) A surface mounter for mounting components on a substrate, comprising: a head unit; a measuring device attached to the head unit for measuring the amount of warpage of the entire substrate by measuring the surface height of a plurality of measurement points on the substrate; and a control unit. The measuring device is a laser measuring instrument for measuring the surface height by irradiating the measurement points on the substrate with a laser beam. The control unit reduces the number of measurement points using the laser beam as the maximum amount of warpage of the substrate decreases.

[0006] According to (1), the smaller the maximum amount of warpage of the substrate, the fewer the number of measurement points using the laser light is adjusted. Therefore, compared to when the number of measurement points is uniform, it is possible to shorten the measurement time for the amount of warpage of the entire substrate and reduce tact time loss.

[0007] (2) In the surface mounter described in (1), the control unit may measure the maximum amount of warpage of the substrate by irradiating a specific location where the warpage is expected to be maximum with a laser beam and measuring the surface height. According to (2), since the maximum amount of warpage of the substrate is actually measured, it is possible to obtain a measurement result with higher reliability than when an empirical value is used.

[0008] (3) In the surface mounter described in (2), the specific location may be the center of the board or its vicinity. According to (3), the board often has the greatest warpage at or near the center of the board, making it the optimum location for measuring the maximum amount of warpage.

[0009] (4) In the surface mounter described in (2), the specific location may be on a line passing through the center of the board or its vicinity. According to (4), when the warpage is maximum not only at the center of the board or its vicinity but also at a position away from the center of the board, it can be detected, thereby improving the measurement accuracy of the maximum amount of warpage of the board.

[0010] (5) In the surface mounter described in (2), the conveying direction of the board is defined as the X direction, and the direction perpendicular to the X direction is defined as the Y direction, and the specific location may be on a first straight line in the Y direction that passes through the center of the board or its vicinity, and on a second straight line in the X direction that passes through the center of the board or its vicinity. According to (5), when the warpage is maximum not only at the center of the board or its vicinity but also at a position off the center of the board, it can be detected, thereby improving the measurement accuracy of the maximum amount of warpage of the board.

[0011] (6) In the surface mounter described in any one of (1) to (5), the control unit may measure the surface height of each measurement point by irradiating the measurement points with laser light in order from the closest measurement point, starting from the measurement point used to measure the maximum amount of warpage of the substrate. According to (6), the measurement path for the surface height of the substrate is short, which reduces the movement time of the laser measuring device. Therefore, the measurement time for the amount of warpage of the entire substrate can be further reduced. [Effects of the Invention]

[0012] According to the present invention, it is possible to shorten the time required to measure the amount of warpage of the entire substrate, thereby reducing tact time loss. [Brief explanation of the drawings]

[0013] [Figure 1] Plan view of surface mounter [Figure 2] Head unit side view [Figure 3] Surface mounter block diagram [Figure 4] Diagram showing the component mounting operation [Figure 5] Diagram showing the operation of measuring the amount of warpage [Figure 6A] Plan view of a board without warpage [Figure 6B] Top view of warped board [Figure 7A] Diagram showing deviation from the real surface (N=3) [Figure 7B] Diagram showing deviation from the real surface (N=5) [Figure 7C] Diagram showing deviation from the real surface (N=7) [Figure 8] Graph showing the relationship between the number of measurement points and the measurement accuracy for the amount of warpage [Figure 9] Illustrative diagram of maximum warpage of board [Figure 10] Surface mounter work process flowchart [Figure 11A] Diagram showing the measurement points for the maximum amount of warpage [Figure 11B] Diagram showing the measurement points for the maximum amount of warpage [Figure 11C]Diagram showing the measurement points for the maximum amount of warpage [Figure 12] Reference Table [Figure 13] Diagram showing the procedure for determining the number of measurement points [Figure 14] Graph showing the relationship between the number of measurement points and measurement time DETAILED DESCRIPTION OF THE INVENTION

[0014] <Embodiment 1> 1. Surface Mounting Machine Description The surface mounter 10 is a device that mounts components E on a substrate PX (operations from component removal to mounting), and as shown in Figures 1 and 2, it is equipped with a base 31, a transport conveyor 32, a head unit 33, and a drive device 34. In the following description, the transport direction of the substrate PX is defined as the X direction, and the direction perpendicular to this is defined as the Y direction. The up-down direction (height direction) is defined as the Z direction.

[0015] The transport conveyor 32 is disposed in the center of the base 31. The transport conveyor 32 is equipped with a pair of transport belts 35, and sends the substrate PX in the X direction on the base 31 to transport it to a working position G. The substrate PX transported to the working position G by the transport conveyor 32 is fixed in a backed-up state by backup pins 57. Then, while the substrate PX is fixed at the working position G, the surface height of the substrate PX is measured by a laser measuring instrument 47.

[0016] A large number of feeders F for supplying components E are arranged side by side on the base 31 so as to surround a work position G in the center of the base. The components E are electronic components such as resistors and capacitors.

[0017] Furthermore, a component recognition camera 43 is installed on the base 31. The component recognition camera 43 has its imaging surface facing upward, and uses the head unit 33 to capture an image of the component E taken out from the feeder F.

[0018] At a work position G in the center of the base, a mounting process is performed by a head unit 33 to mount components E supplied by a feeder F onto a substrate PX.

[0019] The driving device 34 is a device that moves the head unit 33 in a planar direction (X and Y directions) on the base 31. The driving device 34 is made up of a Y-axis ball screw 36, a Y-axis motor 37, an X-axis ball screw 38, and an X-axis motor 39.

[0020] By driving the Y-axis motor 37, the X-beam 40 and the head unit 33 can be moved in the Y direction along the guide rails 41 (Y-axis servo mechanism).

[0021] By driving the X-axis motor 39, the head unit 33 can be moved in the X direction relative to the X-beam 40 (X-axis servo mechanism).

[0022] 2, the head unit 33 is equipped with a plurality of mounting heads 42. The mounting heads 42 are configured to be able to move up and down independently of the head unit 33 by a linear motion mechanism (for example, a screw mechanism) driven by a Z-axis motor 48. In addition, each mounting head 42 is able to rotate around the R axis.

[0023] A negative pressure is supplied to the mounting head 42 from a negative pressure means (not shown), which generates a suction force at the tip of the head. The mounting head 42 can hold the component E by the negative pressure.

[0024] The head unit 33 is also equipped with a board recognition camera 45 and a laser measuring instrument 47. The board recognition camera 45 is fixed to the head unit 33 with its imaging surface facing downward. The laser measuring instrument 47 is fixed to the front wall of the board recognition camera 45 with its measuring surface facing downward.

[0025] The laser measuring device 47 emits a laser beam to the substrate PX fixed at the work position G and receives the reflected light, thereby measuring the height of the substrate surface.

[0026] The substrate recognition camera 45 and the laser measuring instrument 47 can be moved to any position on the substrate PX together with the head unit 33, making it possible for the substrate recognition camera 45 to photograph the substrate surface and for the laser measuring instrument 47 to measure the height of the substrate surface.

[0027] 3, the surface mounter 10 includes a control unit 100, an X-axis motor 39, a Y-axis motor 37, a Z-axis motor 48, a component recognition camera 43, a board recognition camera 45, and a laser measuring instrument 47. The control unit 100 includes a CPU 110 and a memory 120.

[0028] The control unit 100 controls the X-axis motor 39, the Y-axis motor 37, and the Z-axis motor 48 in accordance with a mounting program recorded in the memory 120, and executes the process of mounting the component E on the board PX.

[0029] 2. Relationship between the amount of warpage across the board and the number of measurement points 4 is a diagram showing the support structure for the substrate PX, in which reference numeral 51 denotes a rail guide, reference numeral 52 denotes a substrate holder, reference numeral 55 denotes a backup base that can be raised and lowered, and reference numeral 57 denotes a backup pin that supports the substrate PX. When the substrate PX is not warped, as shown in FIG. 4, the upper surface of the substrate PX is substantially coincident with the upper surface 51A of the rail guide 51.

[0030] 5, the height position of the upper surface of the substrate changes, and the mounting height of the component E also changes. Therefore, the amount of warping of the substrate PX is measured by a laser measuring instrument 47, and the mounting height of the component E relative to the substrate PX is adjusted according to the amount of warping of the substrate PX.

[0031] The amount of warpage W of the substrate PX is the amount of displacement in the surface height of the substrate PX, and in this embodiment, is measured using the upper surface 51A of the rail guide 51 as a reference surface S (see FIG. 5).

[0032] Fig. 6A is a plan view of a substrate PX without warpage, and Fig. 6B is a plan view of a substrate PX with warpage. Fig. 7 is a cross-sectional view taken along line AA in Fig. 6B. P in Fig. 7 indicates the measurement point of the laser light.

[0033] The amount of warpage W of the entire substrate (meaning each position on the substrate) is found by complementing the measurements taken with laser light. Therefore, as shown in Figure 7, the fewer the number of measurement points N with laser light, the larger the deviation α from the actual curved surface C becomes, and the worse the accuracy becomes.

[0034] Figure 8 is a chart showing the relationship between the number of measurement points N and the measurement accuracy for the maximum amount of warpage Wmax. When the tolerance for measurement accuracy is 0.1 mm, the number of measurement points N required to maintain accuracy varies depending on the maximum amount of warpage Wmax, and is smaller as the maximum amount of warpage Wmax is smaller.

[0035] Specifically, when Wmax=3 mm, there are 49 points, when it is 2 mm, there are 36 points, and when it is 1 mm, there are 25 points. Note that the maximum warpage amount Wmax is the maximum value of the warpage amount W of the substrate PX (maximum displacement amount from the reference plane S), as shown in FIG.

[0036] If the maximum amount of warpage Wmax of the substrate PX can be predicted in advance, it is possible to maintain measurement accuracy even if the number of measurement points N is reduced according to the maximum amount of warpage Wmax.

[0037] In this embodiment, a laser beam is irradiated onto a specific location where the warpage is expected to be maximum, and the maximum warpage amount Wmax of the substrate PX is measured in advance.

[0038] Then, the number N of measurement points using laser light is reduced from the initial number N0 by thinning out in accordance with the maximum amount of warpage Wmax. The initial number N0 is the number of measurement points at which accuracy can be maintained regardless of the maximum amount of warpage Wmax, and in this example is 49 points. In this way, the number N of measurement points can be reduced while maintaining the measurement accuracy of the amount of warpage W of the entire substrate.

[0039] 3. Work flow of the surface mounter 10 FIG. 10 shows the flow of work performed by the surface mounter 10 for one board. The workflow is made up of ten steps S10 to S100. First, in S10, the substrate PX is carried into the work position G on the base 31 from the upstream device.

[0040] Thereafter, in S20, the control unit 100 fixes the substrate PX at the work position G, and in S30, moves the head unit 33 to above the substrate PX and photographs and recognizes the FID mark on the substrate PX with the substrate recognition camera 45. The position of the substrate PX can be recognized from the recognition result of the FID mark.

[0041] Thereafter, in S40, the control unit 100 measures the maximum amount of warpage Wmax of the substrate PX fixed at the work position G using the laser measuring device 47. In this example, the measurement is performed by one of the methods (1) to (3).

[0042] (1) The amount of displacement in surface height at one point Pc in the center of the substrate is measured (see FIG. 11A). (2) The amount of displacement of the surface height of the first straight line Ly passing through Pc is measured (see FIG. 11B). (3) The amount of displacement of the surface height of the second straight line Lx passing through Pc is measured (see FIG. 11C). The first straight line Ly is a straight line in the Y direction, and the second straight line Lx is a straight line in the X direction.

[0043] In the case of (1), the measurement result of the surface height of Pc is taken as the maximum amount of warpage. In the case of (2), the maximum amount of change in the surface height of the first straight line Ly is taken as the maximum amount of warpage. In the case of (3), the maximum amount of change in the surface height of the second straight line Lx is taken as the maximum amount of warpage. Furthermore, (2) and (3) may be combined to take the maximum amount of change in the surface height of the first straight line Ly and the surface height of the second straight line Lx as the maximum amount of warpage.

[0044] Thereafter, the process proceeds to step 50, where the control unit 100 determines the number of measurement points N using laser light by referring to the table shown in Fig. 12. For example, if the maximum warpage measured in S40 is Wmax = 0.5 mm, the number of measurement points N is determined to be 16.

[0045] Then, as shown in (a) to (c) of FIG. 13, the measurement points P are thinned out from the initial data of the measurement points P so that the number of measurement points N becomes 16 points.

[0046] As shown in Figure 13(a), the initial data for measurement points P are arranged at equal intervals in a grid pattern so that the distribution is even across the entire substrate. Even when thinning out measurement points P, it is desirable to maintain an even distribution across the entire substrate, so as shown in Figure 13(c), the pitch of measurement points P is widened and the grid is enlarged to maintain the distribution of measurement points P.

[0047] Thereafter, the process proceeds to S60, where the control unit 100 irradiates laser light onto each measurement point P on the substrate PX (in this example, 16 measurement points shown in FIG. 13(c)), and measures the surface height of each measurement point P.

[0048] At this time, it is advisable to set the movement path so that the movement distance of the laser measuring instrument 47 is the shortest. For example, the path may be set so that the measurement point of the maximum warpage amount Wmax is set as the starting position (start position) and the laser measuring instrument 47 moves in order from the closest measurement point to the furthest measurement point. In the example of Fig. 13(d), the center of the substrate is set as the starting position (start position) and a spiral movement path is adopted.

[0049] When the measurement of the surface height of each measurement point P is completed, the process proceeds to S70, where the control unit 100 calculates the amount of warpage W of the entire substrate based on the surface height of each measurement point P. The amount of warpage W of the entire substrate means the amount of warpage W at each position on the substrate, and is obtained by interpolating the measurement results of each measurement point P. The interpolation may be linear interpolation or curve interpolation.

[0050] Thereafter, in S80, the control unit 100 moves the head unit 33 above the feeder F and uses the mounting head 42 to pick up the component E from the feeder F. Then, in S90, the control unit 100 moves the picked up component E onto the board PX and places it on the mounting point on the board PX.

[0051] At this time, the control unit 100 corrects the mounting height of the component E relative to the board PX based on the warpage amount W of the entire board calculated in S70. The mounting height can be corrected by adjusting the stroke of the mounting head 42.

[0052] By correcting the mounting height of the component E, it becomes possible to appropriately press the component E into the substrate PX without depending on the warpage of the substrate PX, and the mounting accuracy of the component E can be maintained.

[0053] The pickup operation in S80 and the mounting operation in S90 are repeated until components E are mounted on all mounting points on the board PX. Then, when components E have been mounted on all mounting points, the process proceeds to S100, and the board PX is transported to a downstream device.

[0054] 4.Effects 14 is a graph showing the relationship between the number of measurement points and measurement time, and the more measurement points there are, the longer it takes to measure the amount of warpage of the entire board. According to the surface mounter 1, the smaller the maximum amount of warpage Wmax of the board PX, the fewer the number of measurement points N using laser light is changed to. Therefore, the time required to measure the amount of warpage of the entire board can be shortened, and tact time loss can be reduced.

[0055] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0056] (1) In the above embodiment, the warp of the substrate PX is convex upward. However, it may be convex downward.

[0057] (2) In the above embodiment, the maximum warpage amount Wmax was measured after the substrate PX was loaded into the surface mounter 10. The maximum warpage amount Wmax may be data measured before the substrate PX was loaded into the surface mounter 10. For example, inspection data from an inspection machine may be used.

[0058] (3) In the above embodiment, the point (specific location) where the amount of warpage of the substrate PX is expected to be maximum is the substrate center Pc. A location near the substrate center Pc may be used as the expected point. The same applies to the first line Ly and the second line Lx, and they may be lines passing near the substrate center Pc. Furthermore, for several substrates after the start of production, the surface height of the substrate PX may be measured at all measurement points using initial data, and the point (specific location) where the amount of warpage is expected to be maximum may be determined based on the trend. Alternatively, past measurement results of the same product type may be recorded, and the point (specific location) where the amount of warpage is expected to be maximum may be determined based on the trend. Furthermore, the user may be able to set this manually.

[0059] (4) In the above embodiment, the laser measuring device 47 is attached to the front wall of the board recognition camera 45. The laser measuring device 47 may be attached directly to the head unit 33. [Explanation of symbols]

[0060] 10 Surface Mounting Machine 33 Head Unit 42 Mounting head 47 Laser measuring instrument (measuring device) 100 control section Ly straight line (first straight line) Lx straight line (second straight line)

Claims

1. A surface mounter that mounts components on a substrate, A head unit and a measuring device attached to the head unit, which measures the amount of warpage of the entire substrate by measuring the surface height of a plurality of measurement points on the substrate; a control unit, the measurement device is a laser measurement instrument that measures the surface height by irradiating a measurement point on the substrate with laser light, The control unit is configured to reduce the number of measurement points using the laser light as the maximum amount of warpage of the substrate decreases.

2. 2. The surface mounter according to claim 1, The control unit measures the maximum amount of warpage of the substrate by irradiating a specific location where the amount of warpage is expected to be maximum with laser light and measuring the surface height.

3. 3. The surface mounter according to claim 2, The specific location is the center of the board or its vicinity.

4. 3. The surface mounter according to claim 2, The specific location is on a straight line passing through the center of the board or its vicinity.

5. 3. The surface mounter according to claim 2, The transport direction of the substrate is defined as an X direction, and the direction perpendicular to the X direction is defined as a Y direction, the specific location is on a first straight line in the Y direction that passes through the center of the board or its vicinity, and on a second straight line in the X direction that passes through the center of the board or its vicinity.

6. 3. The surface mounter according to claim 1, The control unit measures the surface height of each measurement point by irradiating the laser light sequentially from the closest measurement point, starting from the measurement point used to measure the maximum amount of warpage of the substrate.

Images