JP2001189600A - Method for mounting electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mounting electronic parts by which the attitude of electronic parts can be detected accurately. SOLUTION: In the method for mounting electronic parts 7 in which a transfer head is used for picking up the parts 7 and mounting the parts 7 on a substrate, the height H of the lower surface of the parts 7 is measured a plurality of times at prescribed time intervals p by horizontally moving a light shielding type height detecting section provided with a light emitting section and a light receiving section against the parts 7 on a thickness measurement station on which the thickness of the parts 7 is measured while the parts 7 is held by a vacuum nozzle 6 and the attitude of the parts 7 is decided by comparing the maximum value Tmax of the measured thickness values with reference data. Therefore, the attitude of the parts 7 can be detected with accuracy even when the parts 7 has such a shape that is apt to be held in an inclined attitude and a small size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting an electronic component on a substrate.

[0002]

2. Description of the Related Art When mounting an electronic component, it is necessary to inspect whether or not a correct electronic component is picked up by a transfer head in a correct posture. For this reason, in the path for moving the electronic component picked up from the electronic component supply unit to the substrate, an inspection for detecting the size and posture of the electronic component is performed. Hereinafter, measurement of the thickness of an electronic component in a conventional electronic component mounting method will be described.

FIG. 5 is an explanatory diagram of thickness measurement in a conventional electronic component mounting method. In FIG. 5A, a thickness measuring unit using a line sensor is provided on a path along which the electronic component 7 held by the suction nozzle 6 of the transfer head is transported from the supply unit to the substrate. . When the electronic component 7 is positioned on the line connecting the light projecting portion A and the light receiving portion B, when light is emitted from the light projecting portion A, the portion where the electronic component 7 is located is blocked, and Only the light passing through the portion is received by the light receiving section B. Thereby, the height position H of the lower end of the electronic component 7 is detected, and from this height position, the electronic component 7 is detected.
Can be determined.

[0004]

However, since electronic components have been miniaturized with the miniaturization of electronic equipment, FIG.
As shown in (b), there is a case where the corner part of the electronic component 7 partially enters the suction hole of the suction nozzle 6 and is transported in a state where the electronic component 7 is sucked by the suction nozzle 6 in an oblique posture. Since the electronic component 7 sucked in such a posture cannot be mounted normally and causes a mounting failure, it must be removed without being mounted on the substrate.

However, when the above-described thickness measurement is performed in such a state, the result of measuring the height of the lower surface of the electronic component at the center position of the suction nozzle 6 is almost the same as when the electronic component is normally sucked. In some cases, a measured value H ′ may be given. For this reason, even when the pickup is performed in a state of a poor posture, it is determined to be normal in the thickness measurement result, and there is a problem that a mounting failure occurs after mounting on the board.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for mounting an electronic component that can correctly detect the attitude of the electronic component.

[0007]

According to a first aspect of the present invention, there is provided a method of mounting an electronic component, wherein the electronic component is picked up by a transfer head from a supply section of the electronic component and mounted on a substrate. The thickness dimension of the electronic component held in the transfer head is measured a plurality of times while moving the electronic component relative to the thickness measuring means, and the largest one of the measured values obtained by these measurements is determined. The posture of the electronic component is determined by comparing with the reference data.

According to the present invention, the thickness of the electronic component held by the transfer head is measured a plurality of times while moving the electronic component relative to the thickness measuring means, and the measurement obtained by these measurements is performed. By comparing the largest thickness measurement value among the values with the reference data, the posture of the electronic component can be accurately detected.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a plan view of an electronic component mounting apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a thickness measuring station of the electronic component mounting apparatus, and FIG. 3 shows a configuration of a control system of the electronic component mounting apparatus. FIG. 4A is a block diagram, and FIG. 4A is an explanatory diagram of thickness measurement of the electronic component, and FIG. 4B is a graph showing a thickness measurement result of the electronic component.

First, the structure of the electronic component mounting apparatus will be described with reference to FIGS. In FIG. 1, a plurality of parts feeders 2 for supplying electronic components are provided in parallel in a supply unit 1 for electronic components. The parts feeder 2 is mounted on a feeder base (not shown), and moves in the lateral direction by rotating the feed screw 3.

A rotary head 4 is provided in front of the supply unit 1. The rotary head 4 rotates in an index around the main axis O, and a plurality of transfer heads 5 are provided on the circumference thereof. The transfer head 5 has a plurality of suction nozzles 6 (see FIG. 2). The electronic component is picked up from the parts feeder 2 by the lifting / lowering operation of the transfer head 5 while being located at the pickup position P of the suction station. At this time, a desired electronic component can be picked up by moving the parts feeder 2 laterally with the feed screw 3.

The transfer head 5 is a spindle O of the rotary head 4.
The transfer head 5 is rotated around its axis (head rotation center) by a drive mechanism (not shown). By this rotation, a plurality of suction nozzles 6 provided on the transfer head 5 are selected, and the angle of the electronic component held by the suction nozzle 6 in the horizontal rotation direction is set.

The electronic components 7 picked up at the pick-up position P are sequentially moved in the direction of arrow a by the index rotation of the rotary head 4. A thickness measuring station 8 is provided during the movement. The thickness measuring station 8 is provided with a height detecting section 8a as shown in FIG. Hereinafter, the configuration of the height detection unit 8a will be described.

A height detecting section 8a is provided with a table 8b in which a light projecting section A for irradiating light by an LED and a light receiving section B for converting light received by a CCD into an electronic signal are opposed to each other.
It has. The table 8b includes a motor 8c, a nut 8
It can be moved in the horizontal direction by a feed mechanism consisting of d and a feed screw 8e.

With the suction nozzle 6 holding the electronic component 7 positioned between the light projecting section A and the light receiving section B, the light projecting section A
By receiving light emitted from the light receiving unit B, the height position H of the lower end portion at the measurement position of the electronic component 7 held by the suction nozzle 6 is detected. At this time, FIG.
As shown in the figure, by detecting the height position H while moving the table 8b horizontally with respect to the electronic component 7, the height position at a plurality of measurement positions along the length direction of the electronic component 7 is detected. H can be detected.

The height position H0 of the lower end of the suction nozzle 6 in a state where the electronic component 7 is not held is stored in advance by teaching, and the detected height position H of the lower end of the electronic component 7 is stored. By comparing the measured height position H0 of the lower end portion of the suction nozzle 6, the thickness dimension T of the electronic component 7 at the height position measurement position can be obtained. Therefore, the height detecting section 8a serves as a thickness measuring means for measuring the thickness dimension of the electronic component 7.

A component recognition station 9 is provided adjacent to the thickness measuring station 8. The electronic component 7 held by the suction nozzle 6 is imaged from below by a camera at the component recognition station 9. Then, by performing image processing on the imaging result, the dimensions of the electronic component 7 in plan view, that is, the length and width dimensions are detected.

A movable table 11 for positioning a substrate 12 is provided in front of the rotary head 4, and the transfer head 5 moved from the component recognition station 9 is mounted on the substrate 1.
The electronic component 7 is mounted on the substrate 12 by reaching the mounting position M of the mounting station located on the upper surface 2 and performing a lifting operation there.

Next, the configuration of the control system of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 3, a CPU 20 is an overall control unit that controls operations and arithmetic processing of the entire electronic component mounting apparatus. The mechanism drive section 21 drives each mechanism section such as the rotary head 4 for rotating the index and the transfer head 5 for performing the elevating operation. The height detection unit 8a measures the thickness T of the electronic component 7 by detecting the height of the electronic component 7 held by the suction nozzle 6. The image recognition unit 22 recognizes the electronic component 7 held by the suction nozzle 6 and calculates the length and width dimensions and the displacement of the electronic component 7 with respect to the suction nozzle 6.

The allowable value storage unit 23 stores allowable range data such as the thickness dimension T and the width dimension of the electronic component 7 for each electronic component to be mounted. The determination unit 24 compares the thickness T, width, and the like of the electronic component obtained by the image recognition unit 22 and the height detection unit 8a with the reference value data stored in the allowable value storage unit 23 to determine the electronic component. Part 7
Of the electronic component 7 held by the suction nozzle 6 is determined.

This electronic component mounting apparatus is configured as described above. Next, thickness measurement in the thickness measuring station 8 will be described with reference to FIG. First, the electronic component 7 to be measured will be described. As shown in FIG. 4A, the electronic component 7 is a chip having a rectangular parallelepiped shape. When the electronic component 7 is sucked by the suction nozzle, it is necessary to suck the electronic component 7 in a correct posture such that the lower surface is positioned in the horizontal direction. The corner portion of the electronic component 7 has such a shape that it can easily enter the inside of the suction hole.

For this reason, the electronic component 7 may be conveyed while being held by the suction nozzle 6 in an inclined state. The height measurement value of the electronic component 7 at the center of the nozzle detected in this state is almost equal to the height measurement value in the normal posture, and therefore, the conventional thickness measurement cannot correctly detect such a posture defect. Therefore, in this embodiment,
The thickness is measured by the following method.

FIG. 4A shows a state in which the suction nozzle 6 holding the electronic component 7 in the inclined position as described above is stopped at the thickness measuring station 8. In this state, FIG.
The light receiving unit B receives the irradiation light from the light projecting unit A while horizontally moving the table 8b shown in FIG.
Height measurement values H at a plurality of measurement positions are obtained. (A), (b), and (c) of FIG. 4A show a state in which the table 8b is sequentially moved to change the relative position between the light receiving unit B and the electronic component 7.

The graph shown in FIG. 4B shows the change in the height measurement value H in the process of changing the relative position, that is, the height measurement value H at every predetermined pitch p on the horizontal axis indicating the moving distance.
Is plotted, and shows the results of a plurality of measurements performed at each predetermined pitch. As can be seen from the graph, the measurement result obtained here conforms to the shape of the lower surface of the electronic component 7 in a tilted state, and from this measurement result, the lowest height measurement value Hmin of the electronic component 7 is obtained.
(A height measurement value at a measurement position corresponding to (b) shown in FIG. 4A) can be obtained, and the height measurement value Hm
The largest thickness measurement value Tmax is obtained from in and H0.

By comparing the measured thickness value Tmax with the reference value stored in the allowable value storage unit 23,
It can be determined whether or not the electronic component 7 is held in a correct posture. That is, here, the electronic component 7
Is measured a plurality of times while the electronic component 7 is relatively moved with respect to the height detecting unit 8a as the thickness measuring means, and the largest thickness measured value Tmax among the measured values obtained by these measurements is used as the reference data. By comparing with, the attitude of the electronic component 7 is determined.

The measured thickness T of the electronic component 7 in a tilted state
Since the max is always larger than the reference value indicating the thickness dimension of the electronic component in the correct posture, the adoption of such a posture determination method does not cause the inclined state to be erroneously determined to be the correct posture. .

In this embodiment, an electronic component mounting apparatus having a rotary head for rotating an index has been described as an example. However, the present invention is not limited to this. The present invention can be applied to an electronic component mounting apparatus having a transfer mechanism as long as the apparatus has electronic component thickness measuring means.

[0028]

According to the present invention, the thickness of the electronic component held by the transfer head is measured a plurality of times while moving the electronic component relative to the thickness measuring means. The largest thickness measurement value among the measured values is compared with the reference data, so even if the target is a micro-sized electronic component that is likely to be held in a tilted position, the position of the electronic component can be accurately detected. It is possible,
It is possible to prevent the mounting failure from being mounted on the board while maintaining the posture.

[Brief description of the drawings]

FIG. 1 is a plan view of an electronic component mounting apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a thickness measuring station of the electronic component mounting apparatus according to the embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of a control system of the electronic component mounting apparatus according to the embodiment of the present invention;

FIG. 4A is a diagram illustrating a thickness measurement of an electronic component according to an embodiment of the present invention. FIG. 4B is a graph illustrating a thickness measurement result of the electronic component according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of thickness measurement in a conventional electronic component mounting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Supply part 2 Parts feeder 4 Rotary head 5 Transfer head 6 Suction nozzle 7 Electronic component 8 Thickness measuring station 8a Height detection part 12 Substrate T Thickness dimension

Claims (1)

[Claims] An electronic component mounting method for picking up an electronic component from a supply section of the electronic component by a transfer head and mounting the electronic component on a substrate, wherein the electronic component held by the transfer head has a thickness dimension. The attitude of the electronic component is determined by measuring the electronic component a plurality of times while moving the electronic component relative to the measuring means, and comparing the largest thickness measurement value among the measurement values obtained by these measurements with reference data. A method for mounting an electronic component, comprising: