JP2822448B2 - Electronic component mounting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention automatically detects and corrects nozzle misalignment caused by expansion and contraction of a machine due to a change in environmental temperature, bending of a nozzle, and the like. The present invention relates to a method for mounting an electronic component on a substrate with high accuracy.

(Prior Art) FIG. 5 is a plan view showing a state in which electronic components are mounted on a substrate by a conventional electronic component mounting apparatus. 101,
102 is an XY direction moving device, 103 is a transfer head provided in the Y direction moving device 102, 104 is its nozzle, OA is the origin of movement of the nozzle 104, OB is the center of the nozzle 104, and 105 is the electronic component P
Observation device for observing the positional shift of the camera, 106 and 107 are the stage and camera, OC is the optical axis of the camera 107, and OD is the stage 106.
The center 108 of the electronic component P mounted on the substrate is a substrate.

Next, the operation will be described. First, an electronic component P provided in a toilet or the like is moved to a stage 106 by means (not shown).
Then, the camera 107 observes the optical axis OC, that is, the displacement △ x, △ y of the center OD from the coordinate origin on the camera 107 side, which is the reference point of the displacement of the electronic component P. Next, the XY direction moving devices 101 and 102 are driven, and the nozzle 104
The center OB of the electronic component P to the center OD,
The lower end of the nozzle 104 lands on the upper surface of the electronic component P, and the electronic component P is taken up and transferred to a predetermined position on the substrate 108.

In this case, the coordinate position XC, Y of the optical axis OC with respect to the movement origin OA
C is known in advance. Therefore, the above positional deviation △ x, △ y
Is added to the command value (XC ± △ x, YC ± △ y).
Is moved in the X and Y directions so that the center OB of the nozzle 104 coincides with the center OD of the electronic component P to take up the iron.

However, a displacement of the center OB of the nozzle 104 occurs due to expansion and contraction of the machine due to a change in the environmental temperature, bending of the nozzle 104, or assembling due to long-time operation. Therefore, the above command values (XC ± Cx), (YC ± △
y) to drive the XY-direction moving devices 101 and 102, the center OB of the nozzle 104 does not match the center OD of the electronic component P correctly, lands at a position deviated from the center OD and takes up, and Since the transfer is carried to 108, an error in the XY direction occurs at the mounting position, and the mounting accuracy is reduced.

Conventionally, there has been no device that automatically detects and corrects the positional shift of the nozzle 104, and thus the following operation has been performed. That is, the board 108 on which the electronic component P is mounted is sometimes extracted, and the worker observes the board 108 with a microscope or the like. Therefore, when a displacement (constant error) having the same tendency is observed in a large number of electronic components, the displacement is determined to be a mechanical error based on the displacement of the nozzle 104, and the displacement is eliminated. , The whole device was readjusted.

(Problems to be Solved by the Invention) However, the above-mentioned conventional means requires a great deal of labor and time.

Therefore, an object of the present invention is to provide a means for automatically detecting and correcting a nozzle position shift and mounting an electronic component on a substrate with high accuracy.

(Means for Solving the Problems) For this purpose, according to the present invention, an electronic component provided in an electronic component supply unit is transferred onto a stage of an observation device by a sub-transfer head, and provided in the observation device. Camera detects the center of this electronic component, and then moves the transfer head
The electronic component is moved upward by driving the XY-direction moving device, the center of the nozzle of the transfer head is made to coincide with the center of the electronic component, and the electronic component is taken up. During the mounting process of the electronic component to be transferred and mounted on the positioned substrate, the following nozzle misalignment correction process is performed: (i) A sample is placed on the stage, and the sample is provided on this stage. (Ii) Next, the XY direction moving device is driven by driving the XY direction moving device so that the center of the nozzle of the transfer head coincides with the center of the sample. Work to take up this sample by this nozzle (iii) Then, the nozzle is moved to its axis by the motor provided on the transfer head. After having allowed a certain angle rotated about,
The operation of placing the sample on the stage again and detecting the coordinates of the center again (iv) The operation of calculating the positional deviation of the center of the nozzle from the coordinates of the center of the sample detected twice as described above. This is to intervene a nozzle misalignment detection process.

(Operation) During the process of repeatedly mounting the electronic components on the stage on the substrate by the transfer head, the nozzle misalignment detecting process of (i) to (iv) is intervened to reduce the misalignment of the nozzle. The electronic component is mounted on the substrate by driving the XY-direction moving device so that the positional deviation is corrected after that.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an electronic component mounting apparatus.
Is a table, on both upper sides of which are provided a supply section 3 for a first electronic component P composed of a magazine 2 and a supply section 5 for a second electronic component composed of a tape unit 4. A substrate 6 comprising clamping means is provided between the supply units 3 and 5.
Are provided. Reference numeral 8 denotes a conveyor for carrying the substrate 6 into and out of the positioning unit 7, and reference numeral 9 denotes a toilet for storing the electronic components P mounted on the magazine 2.

Numeral 12 denotes a drive box erected on the side of the table 1, on which XY direction moving devices 13 and 14 are disposed. Reference numerals 15 and 16 denote drive motors. Reference numeral 17 denotes a mounting portion mounted on the lower surface of the XY direction moving device 13, and reference numerals 18 and 19 denote the mounting portions 1
Camera and transfer head integrated into 7, 20 is its nozzle, 21 is the LED mounted on the front of the mounting part 17
This is a light source composed of a surface light emitter.

Reference numeral 22 denotes a θ-direction driving device including a motor 22a and a belt 22b.The rotation device 22 rotates the nozzle 20 around an axis so as to correct the positional deviation in the θ direction of the electronic component sucked to the lower end of the nozzle 20. Do. Reference numeral 30 denotes an observation position of the electronic component P provided between the supply unit 3 and the positioning unit 7, and reference numeral 26 denotes a sub-transfer head for transferring the electronic component P on the tray 9 to the observation device 30. Reference numerals 27 and 28 denote driving motors and tow wires for moving the sub-transfer head 26 in the XY direction, and constitute a device for moving the sub-transfer head 26 in the XY direction.

FIG. 2 shows the details of the observation device 30. The observation device 30 includes a stage 30a on which the electronic component P is placed.
And a camera 30b for observing the displacement of the electronic component P on the stage 30a. Electronic components P are provided on the stage 30a.
A reflection plate 32 is obliquely provided below a translucent stage plate 31 such as a glass plate on which a camera 30 is placed, and a camera 30 is provided beside the reflection plate 32.
b is provided. Numeral 34 is a light-transmitting plate disposed immediately below the stage plate 31, and a space 35 is secured between the two plates 31, 34. An intake hole 36 is provided at the center of the stage plate 31.
The electronic component P is fixed on the seat 38 by negative pressure on the stage plate 31 by sucking air in the space 35 from a suction hole 37 by a pump (not shown),
In this state, the light source 21 moves above the stage 30a and irradiates the light downward, thereby observing the electronic component P as a silhouette with the camera 30b and detecting the positional shift of the electronic component P in the XYθ direction.

Numeral 40 denotes a mounting portion for the electronic component sample S provided integrally with the observation device 30 on the observation device 30. This sample S
As will be described in detail later, this is transferred onto the stage 30a, and the position of the nozzle 20 in the XY direction is corrected while observing with the camera 30b. As the sample S, for example, an electronic component having a good external shape is selected. If not so high accuracy is required for correcting the positional deviation of the nozzle 20, the mounting portion 40 is not provided, and an arbitrary electronic component P in the tray 9 is selected as a sample, and the electronic component P is transferred to the stage 30a. It may be transferred and mounted on the top.

This device has the above configuration, and the mounting operation will be described next.

First, the XY direction moving devices 13 and 14 are driven to transfer the camera 18 above the substrate 6, and the camera 18 observes a print pattern printed on the substrate 6 to detect a displacement in the XYθ direction. . The sub-transfer head 26 transfers the electronic component P on the tray 9 to the stage 30a of the observation device 30, and
The position shift of the electronic component P in the XYθ direction is recognized based on 0b.

FIG. 3 shows the situation, where OA is the nozzle 20
The origin of movement, P is the electronic component placed on the stage 30a, O
C is the optical axis of the camera 30b, OD is the center of the electronic component P, XC, Y
C is the coordinate position of the optical axis OC in the coordinate system of the movement origin OA, and as shown in the partially enlarged view, the electronic component P is displaced by △ x, △ y, △ θ in the XYθ direction. The electronic component P is a QFP having leads L in four directions, and requires high mounting accuracy.

Next, the command value (XC ± △
x) and (YC ± △ y), the XY-direction moving devices 13 and 14 are driven to land the center OB of the nozzle 20 at the center OD of the electronic component P that is displaced and take up the electronic component. The position shift Δx, Δy of P is corrected. The means for correcting △ x and △ y as described above is the same as the conventional means described with reference to FIG.

Next, while the electronic component P on the stage 30a is being taken up by the nozzle 20 and transferred to the substrate 6, the motor
By driving the nozzle 22a to rotate the nozzle 20 about the axis, the displacement of the electronic component P and the printed pattern of the substrate 6 in the θ direction is corrected, and the substrate detected as described above is further corrected. The electronic components P are mounted on the substrate 6 by driving the XY direction moving devices 13 and 14 in order to compensate for the positional deviation of the print pattern 6 in the XY direction. Control of the motors 15, 16, 22a and the like is performed by a control device such as a computer (not shown). The electronic component P of the tape unit 4 is mounted on the board 6 by means different from the above-described means, but the description is omitted.

By the way, as mentioned above, the above-mentioned means
Observing the displacement of the electronic component P on the stage 30a in the XYθ direction, and then moving the nozzle 20 to the center OD of the electronic component P.
The electronic component P is taken up by the nozzle 20 while the center OB of the electronic component P is made coincident with the center OB, thereby correcting the displacement of the electronic component P in the XY direction. Therefore, this means includes a movement origin OA of the nozzle 20 by the XY direction movement devices 13 and 14.
There is a first coordinate system having the origin as the origin and a second coordinate system having the optical axis OC of the camera 30b as the origin. Then, the coordinate values XC and YC of the optical axis OC with respect to the origin OA (see FIG. 3), that is, the positional relationship between the first coordinate system and the second coordinate system are known,
Therefore, as described above, the command values (XC ± △ x), (YC ± △) obtained by adding the above-mentioned positional deviations △ x, △ y to the coordinate values XC, YC.
If the XY direction moving devices 13 and 14 are driven by y), the nozzle 2
The center OB of 0 can be matched with the center OD of the electronic component P. However, misalignment of the nozzle 20 is likely to occur due to expansion and contraction of members due to changes in the environmental temperature, bending of the nozzle 20, and assembling of the apparatus during long-time operation. When it becomes scratched, the nozzle
Even if 20 is moved in the XY direction, its center OB does not coincide with the center OD of the electronic component P.

Therefore, in this means, as described above, the stage 30a
While the process of repeatedly transferring and mounting the electronic component P on the substrate 6 is being repeated, the following process of detecting the positional deviation of the nozzle 20 is appropriately interposed.

That is, first, the sample S of the mounting section 40 is transferred to the stage 30a by the transfer head 19, and the coordinates (図 x1, △ y1) of the center OS1 are detected by the camera 30b as shown in FIG. Then, the XY direction moving devices 13 and 14 are driven so that the center OB of the nozzle 20 coincides with the center OS1, and the sample S is taken up by the nozzle 20. Next, the motor 22a is driven to rotate the nozzle 20 around an axis thereof at an arbitrary angle (for example, 180 °). Next, the sample S is mounted on the stage 30a again, and the coordinates (△ x2, △ y2) of the center OS2 are detected again by the camera 30b (see the chain line in the figure).

Here, if the first center OS1 matches the second center OS2, it is determined that there is no displacement of the nozzle 20. However, as shown in FIG.
If the center moves from OS1 to OS2 by rotating by 180 °, the nozzle 20 is displaced, and the center OB has the coordinates of the first center OS1 (△ x1,
Δy1) and the coordinates of the second center OS2 (Δx2, Δy2)
At the midpoint of Therefore, the coordinates of the center OB of the nozzle 20 And the center OB displacement Is calculated. Thereafter, by driving the XY-direction moving devices 13 and 14 while correcting this positional deviation, the center OB of the nozzle 20 is made coincident with the center OD of the electronic component P, and the substrate 6 is transferred. Mount.

As described above, according to the present means, during the electronic component mounting process, the above-described misalignment detection process of the nozzle 20 is appropriately interposed to detect the misalignment of the nozzle 20 and to correct the misalignment of the nozzle 20 in the XY direction. By driving the moving devices 13 and 14, a decrease in mounting accuracy can be prevented.

Note that the center OB is misaligned as described above. Is calculated, this misalignment is corrected and the nozzle
It is desirable to confirm that the detection and correction of the displacement have been performed correctly by taking up the sample S by 20 and rotating it 180 ° to confirm that the center does not move.

(Effects of the Invention) As described above, according to the present invention, nozzle misalignment caused by expansion and contraction of a machine due to a change in environmental temperature, bending of a nozzle, or looseness in assembly due to long-term operation, etc., is detected. This can be corrected and the electronic component can be accurately mounted on the board. In addition, the present invention does not require a special position for detecting a nozzle position shift or correcting the detected position shift, and has an advantage that it can be easily handled by a computer out process.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a perspective view of an electronic component mounting apparatus, FIG. 2 is a sectional view of an observation apparatus, FIG. 3 is a plan view during observation, and FIG. Plan view during correction, fifth
The figure is a plan view of the conventional means. 3. Electronic part supply section 6. Substrate 7. Positioning section 13, 14 XY moving device for transfer head 18 Camera 19 Transfer head 20 Nozzle 22a Motor 30 … Observation device 30a… Stage 30b… Camera P… Electronic components S… Sample OB… Nozzle center OD… Electronic component center OS1… First sample center coordinates OS2… Second Sample center coordinates

Claims (1)

(57) [Claims] An electronic component provided in a supply section of the electronic component is transferred onto a stage of an observation device by a sub-transfer head, and a center of the electronic component is detected by a camera provided in the observation device. Then, the transfer head is moved above the electronic component by driving the XY direction moving device, the center of the nozzle of the transfer head is made to coincide with the center of the electronic component, and the electronic component is taken up. During the mounting process of the electronic component in which the electronic component is transferred and mounted on the substrate positioned at the positioning portion, the following nozzle misalignment detecting process is performed: (i) a sample is placed on the stage, and Observing the sample with a camera provided on this stage and detecting the coordinates of the center of this sample (ii) Next, the center of the nozzle of the transfer head To move the nozzle to its center by driving the XY-direction moving device so that the sample coincides with the center of the sample, and taking up the sample by the nozzle. After rotating a fixed angle around the heart,
The operation of placing the sample on the stage again and detecting the coordinates of the center again (iv) The operation of calculating the positional deviation of the center of the nozzle from the coordinates of the center of the sample detected twice as described above. A method for mounting an electronic component, comprising intervening a nozzle displacement detection step.