JP4039222B2 - Electronic component mounting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting method for mounting electronic components on a substrate.
[0002]
[Prior art]
In electronic component mounting for mounting electronic components on a substrate, a pickup operation for picking up an electronic component stored in a component supply unit by a mounting head and a predetermined mounting point on the substrate by a mounting head moved onto the substrate The component mounting operation for landing is performed. In this component mounting operation, it is necessary to lower the suction nozzle holding the electronic component by the elevating means provided in the mounting head and to stop the electronic component correctly at the height position of the upper surface of the substrate.
[0003]
Conventionally, the height position of the upper surface of the substrate is given in advance as mounting height data, and in the mounting operation, a method of controlling the above-described lifting means based on the mounting height data is common. On the other hand, when mounting a board of a type whose plane accuracy is not ensured due to swell or warp, the board warpage is measured in advance, and the mounting height data is used as the mounting height data during the mounting operation. A method using a warp data is used (see, for example, Patent Document 1). Due to this, when the substrate surface is in a downwardly concave state, the electronic component does not reach the substrate surface yet and is in a distant position so that it can be released, etc. Can be prevented.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-269692
[Problems to be solved by the invention]
However, in the above method, since it is necessary to measure the substrate to be mounted in advance to obtain warpage data, it is necessary to repeat the measurement work for each lot when targeting multiple types of substrates, It was not necessarily a practical method. Moreover, even when the measurement data is obtained, if there is a mistake in data input or the like, a failure cannot be avoided.
[0006]
Therefore, an object of the present invention is to provide an electronic component mounting method that can eliminate mounting defects caused by mounting height.
[0007]
[Means for Solving the Problems]
The electronic component mounting method according to claim 1 is an electronic component mounting method in which an electronic component is picked up from a component supply unit by a mounting head having a suction nozzle and mounted on a substrate, and the suction is performed by lowering the mounting head. In the component mounting operation for landing the electronic component held by the nozzle on the substrate, the component contact timing at which the electronic component contacts the substrate is detected by the contact detection means provided in the mounting head, and this component contact timing The vacuum suction means for vacuum suction from the suction nozzle and the lifting means for raising and lowering the mounting head are controlled based on the above, and the contact detection means is provided in a nozzle holder provided in the mounting head. A contact member, a probe provided facing the upper surface of the contact member, and the contact member and the probe are connected to each other. The continuity detecting unit detects that the abutment member and the probe are in contact with each other when an upward force is applied to the lower end of the suction nozzle, and is held by the suction nozzle. It was detected that the electronic component touched the surface of the substrate .
[0008]
The electronic component mounting method according to claim 2 is the electronic component mounting method according to claim 1, wherein the suction nozzle at the component contact timing is based on the component contact timing detected by the contact detection means. obtains the height position, as compared to the normal height position range previously stored look et the height position, only if the height is within the normal height position range, the component placing operation Continue to run.
[0009]
According to the present invention, the abutting detection means provided in the mounting head detects the component abutting timing when the electronic component abuts on the substrate, and the elevating means for raising and lowering the mounting head based on the component abutting timing; By controlling the vacuum suction means for vacuum suction from the suction nozzle, it is possible to secure an appropriate mounting height and reduce mounting defects.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will 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 diagram illustrating a configuration of a transfer head of the electronic component mounting apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a configuration of a control system of an electronic component mounting apparatus according to an embodiment of the present invention, and FIG. 4 is a block diagram showing a configuration of a control system of the electronic component mounting apparatus according to an embodiment of the present invention. FIG. 6 is a flowchart of the electronic component mounting operation by the electronic component mounting apparatus according to the embodiment of the present invention. FIG. 6 is a process explanatory diagram of the electronic component mounting operation in the electronic component mounting method of the embodiment of the present invention. 7 is an explanatory diagram of mounting height determination in the electronic component mounting method according to the embodiment of the present invention.
[0011]
First, the structure of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 1, a transport path 2 is disposed in the center of the base 1 in the X direction. The conveyance path 2 conveys the board 3 and positions it at the mounting position of the electronic component. On both sides of the conveyance path 2, component supply units 4 are arranged, and each component supply unit 4 has a large number of tape feeders 5 arranged in parallel. The tape feeder 5 stores chips (electronic components) held on the tape and supplies the tape by pitch feeding.
[0012]
Y-axis tables 6A and 6B are disposed on both ends of the upper surface of the base 1, and two X-axis tables 7A and 7B are installed on the Y-axis tables 6A and 6B. By driving the Y-axis table 6A, the X-axis table 7A moves horizontally in the Y direction, and by driving the Y-axis table 6B, the X-axis table 7B moves horizontally in the Y direction. The X-axis tables 7A and 7B are equipped with a transfer head 8 and a camera 9 that moves integrally with the transfer head 8, respectively.
[0013]
When the Y-axis table 6A, the X-axis table 7A, the Y-axis table 6B, and the X-axis table 7B are driven in combination, the transfer head 8 moves horizontally, and the chip is picked up from each component supply unit 4 by the suction nozzle. And mounted on the substrate 3 positioned in the transport path 2. The camera 9 that has moved onto the substrate 3 captures and recognizes the substrate 3.
[0014]
A line camera 11 and a nozzle stocker 12 are disposed on the path from the component supply unit 4 to the conveyance path 2. The line camera 11 captures an image of the chip held by each transfer head 8 from below. The nozzle stocker 12 accommodates various types of suction nozzles corresponding to the suction target chip, and the suction heads can be replaced when the transfer head 8 accesses the nozzle stocker 12.
[0015]
Next, the transfer head 8 will be described with reference to FIG. As shown in FIG. 2, the transfer head 8 is multi-type and includes a plurality of suction heads 10 as mounting heads. These suction heads 10 move integrally with the camera 9. Each suction head 10 includes an elevating mechanism 10a provided at the upper end portion, a shaft mechanism portion 10b extending downward from the elevating mechanism 10a, and a nozzle holder 10c provided at the lower end portion of the shaft mechanism portion 10b. The nozzle holder 10c is detachably mounted with a suction nozzle 14 that sucks and holds the chip, and is exchanged according to the type of chip.
[0016]
Each suction nozzle 14 can be moved up and down individually by a lifting mechanism 10a which is a lifting means, and can be rotated around a shaft by a common θ-axis motor 13. Each of the elevating mechanisms 10a is provided with a Z-axis motor (not shown), and the height position detector 15 receives a pulse signal from an encoder provided in the Z-axis motor, and is attached to the nozzle holder 10c. The height position of the lower end of the suction nozzle 14 can be detected.
[0017]
Here, with reference to FIG. 3, the attachment of the suction nozzle 14 to the suction head 10 and the vacuum suction system will be described. The nozzle holder 10c provided at the lower end portion of the shaft mechanism portion 10b is mounted so as to be allowed to move up and down by a predetermined stroke with respect to the shaft mechanism portion 10b, and is always mounted by an urging means incorporated in the shaft mechanism portion 10b. It is biased downward. A connection hole 10d for external connection is provided on the side surface of the shaft mechanism portion 10b. A vacuum valve 16 is connected to the connection hole 10d, and the vacuum valve 16 is further connected to a vacuum pump 17.
[0018]
The suction nozzle 14 has a configuration in which a shaft-shaped main body portion 14a and a disc-shaped flange portion 14c are provided below a tapered fitting locking portion that fits into the mounting hole of the nozzle holder 10c. The collar part 14c functions as a reflecting plate that reflects the illumination light emitted from the illumination part attached to the line camera 11.
[0019]
The main body portion 14a is provided with a suction hole 14b penetrating vertically. When the suction nozzle 14 is clamped by the clamp member 10e and attached to the nozzle holder 10c, the suction hole 14b is connected to the shaft mechanism portion 10b. The vacuum valve 16 communicates with the hole 10d. In this state, the vacuum pump 17 is driven, and the vacuum valve 16 is opened and vacuum suction is performed from the suction nozzle 14 to suck and hold the chip in the suction hole 14b. Then, by closing the vacuum valve 16 and stopping the vacuum suction, the chip is released from the suction and detached from the suction nozzle 14. The vacuum pump 17 and the vacuum valve 16 serve as vacuum suction means for vacuum suction from the suction nozzle 14.
[0020]
Next, contact detection means for detecting that the chip held by the suction nozzle 14 has contacted the substrate will be described. The nozzle holder 10c is provided with a disk-like contact member 18, and a probe 19 provided so as to extend downward from the shaft mechanism portion 10b is opposed to the upper surface of the contact member 18. The contact member 18 and the probe 19 are connected to the continuity detection unit 20.
[0021]
The probe 19 is provided with a buffer spring. Even if an upward force is applied to the lower end of the probe 19, the probe 19 is allowed to be displaced upward by the amount of bending of the spring to prevent damage. It has become. When an upward external force acts on the lower end portion of the suction nozzle 14, the nozzle holder 10 c is displaced upward together with the suction nozzle 14, and the contact member 18 contacts the probe 19.
[0022]
The contact between the probe 19 and the contact member 18 is electrically detected by the continuity detection unit 20, thereby detecting that an upward force is applied to the lower end portion of the suction nozzle 14. By executing the upward force acting on the suction nozzle 14 during the chip mounting operation by the suction head 10, it is detected that the chip held by the suction nozzle 14 has come into contact with the surface of the substrate. The That is, the contact member 18, the probe 19, and the continuity detection unit 20 serve as contact detection means.
[0023]
Next, the configuration of the control system of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 4, a CPU 21 is a calculation unit, and performs various processes and calculations by executing a program stored in the program storage unit 22 using data stored in the data storage unit 23. The program storage unit 22 stores various programs such as an electronic component mounting operation by the transfer head 8 and an operation program for substrate transport operation. The data storage unit 23 stores mounting data 23 a indicating the mounting position and chip size of a chip mounted on the substrate 3 and mounting height data 23 b indicating the height position of each mounting point on the substrate 3.
[0024]
The continuity detection unit 20 detects that the chip held by the suction nozzle 14 has come into contact with the substrate by detecting that the probe 19 is in conduction with the contact member 18 in the suction head 10. The height position detection unit 15 detects the height position of the lower end portion of the suction nozzle 14 based on the pulse signal from the lifting mechanism 10 a of the suction head 10.
[0025]
In the mounting operation in which the suction nozzle 14 holding the chip is lowered with respect to the substrate 3 to land the chip on the substrate 3, a mounting height determination described later is performed. That is, by detecting the height position of the suction nozzle 14 at the timing when the contact of the chip is detected by the continuity detection unit 20, and comparing the detected height position with the above-described mounting height data 23b, It is determined whether or not the mounting operation has been performed normally.
[0026]
The mechanism drive unit 24 drives mechanism units such as the X-axis tables 7A and 7B, the X-axis tables 6A and 6B, and the transfer head 8. The image recognition unit 25 recognizes the position of the substrate 3 by recognizing image data obtained by imaging of the camera 9, and recognizes the image data obtained by imaging of the line camera 11, thereby performing suction. The position of the chip held by the nozzle 14 is recognized. The suction control unit 26 controls the suction holding / release of the chip by the suction nozzle 14 by controlling the opening and closing of the vacuum valve 16.
[0027]
This electronic component mounting apparatus is configured as described above, and the mounting operation in the electronic component mounting method will be described below with reference to FIG. 6 along the mounting operation flow of FIG. First, the transfer head 8 is moved to the component supply unit 4, and the suction head 10 is moved up and down with respect to the tape feeder 5, thereby sucking the chip P by the suction nozzle 14 as shown in FIG. (ST1). Next, the transfer head 8 passes above the line camera 11 and moves above the substrate 3. At this time, the chip P held by the suction nozzle 14 is imaged by the line camera 11, and thereby the chip P is recognized (ST2).
[0028]
Thereafter, the transfer head 8 moves to the substrate mounting position (ST3), and aligns the suction head 10 with respect to the mounting point. Next, as shown in FIG. 6B, the suction head 10 is lowered (ST4). Thereby, the chip P held by the suction nozzle 14 comes into contact with the upper surface of the substrate 3. When the suction head 10 is slightly lowered from this state, as shown in FIG. 6C, the probe 19 is brought into contact with the contact member 18c to be conducted, whereby the contact of the chip P with the substrate 3 is prevented. It is detected (ST5).
[0029]
In response to this conduction detection, the suction control unit 26 controls the vacuum valve 16 to stop the vacuum suction from the suction nozzle 14. As a result, the adsorption of the chip P is released, and the chip P is mounted on the substrate 3 (ST6). Next, as shown in FIG. 6D, after the chip P is detached from the substrate 3, the suction head 10 moves up (ST7). Thereby, the mounting operation of the chip P is completed.
[0030]
In the electronic component mounting method, in the component mounting operation in which the chip P held by the suction nozzle 14 is landed on the substrate 3 by lowering the suction head 10, the chip P is mounted by the contact detection means provided in the mounting head 10. The component contact timing contacted with the substrate 3 is detected, and on the basis of this component contact timing, the lifting mechanism 10a for lifting and lowering the suction head 10 and the vacuum valve 16 of the vacuum suction means for vacuum suction from the suction nozzle 14 are controlled. It has a form.
[0031]
Next, detection of contact of the chip P with the substrate 3 and mounting height determination in the mounting operation will be described with reference to FIG. In (ST5) in the flow of FIG. 6, the contact of the chip P held by the suction nozzle 14 is detected. In this contact detection, the chip P is not necessarily in the normal state on the upper surface of the substrate 3. It is not guaranteed that they have come into contact with each other. For example, when foreign matters such as dropped parts are present at the mounting point on the substrate 3, the chip P comes into contact with these foreign matters when the suction nozzle 14 is lowered.
[0032]
If the mounting operation is continued in such an abnormal state, not only a mounting error occurs but also a machine trouble such as nozzle breakage is induced. In the electronic component mounting method shown in the present embodiment, The mounting height described below is determined at the contact detection timing to determine whether a normal mounting operation is being performed.
[0033]
FIG. 7 shows a normal height position range of the mounting height in the component mounting operation. The substrate to be mounted does not always have a good planar accuracy, and the surface height may vary due to undulation or warpage. Even in the case of targeting such a substrate, in the mounting operation by the electronic component mounting apparatus shown in the present embodiment, the contact of the chip P to the substrate 3 is detected by the contact detection means. Regardless of whether the height of the substrate surface varies or not, the suction nozzle 14 can perform suction release at the correct timing.
[0034]
However, when the degree of height variation is locally significant, or when a foreign object is present at the mounting point, the mounting operation cannot be continued as it is, and some countermeasure is required. For this reason, in the electronic component mounting method of the present embodiment, as shown in FIG. 7, the upper allowable height HU and the lower allowable height from the normal position of the surface 3a of the substrate 3 upward and downward, respectively. The upper limit U and the lower limit L separated by HL are set as a normal height position range in which the mounting operation can be normally performed, and are stored in the data storage unit 23 as mounting height data 23b. The upper allowable height HU and the lower allowable height HL are allowable heights at which the chip P can be normally mounted on the upper convex substrate 3 and the lower concave substrate 3, respectively.
[0035]
Based on the component contact timing detected by the above-described contact detection means, the height position of the lower end portion of the suction nozzle 14 at the component contact timing is obtained by the height detection unit 15 and the obtained height position is obtained. Is compared with the normal height position range included in the pre-stored mounting height data 23b, and the component mounting operation is continuously executed only when the detected height position is within the normal height position range. Like to do. In the mounting height data 23b, the height position including the thickness dimension t of the chip P is stored for each mounting point, and even when different parts having different thickness dimensions are erroneously mounted, It is possible to detect erroneous mounting as a deviation from the above.
[0036]
That is, when the detected height position is out of the above-described normal height position range, it is determined that the mounting operation is not performed normally, the mounting operation is stopped, and the notification means notifies that effect. Inform. Examples in which the mounting operation is not normally performed include a case where the substrate is excessively warped and deformed, a foreign object is present at a mounting point on the substrate, and the above-described erroneous mounting of different parts.
[0037]
As described above, in the electronic component mounting method shown in the present embodiment, the component contact timing when the chip contacts the substrate is detected, and the suction release of the suction nozzle and the suction head are based on the component contact timing. Trying to make a rise. As a result, even when the board to be mounted is warped, the proper mounting height can be secured without performing complicated operations such as pre-measurement of the board and input of measurement data required by the conventional method. Mounting defects such as chip misalignment can be reduced.
[0038]
【The invention's effect】
According to the present invention, the abutting detection means provided in the mounting head detects the component abutting timing when the electronic component abuts on the substrate, and the elevating means moves the mounting head up and down based on the component abutting timing. And by controlling the vacuum suction means for vacuum suction from the suction nozzle, it is possible to secure an appropriate mounting height and reduce mounting defects.
[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 diagram illustrating a configuration of a transfer head of the electronic component mounting apparatus according to an embodiment of the present invention. The block diagram which shows the structure of the control system of the electronic component mounting apparatus of one Embodiment of this invention. [FIG. 4] The block diagram which shows the suction head with which the transfer head of the electronic component mounting apparatus of one Embodiment was equipped. FIG. 6 is a flowchart of the electronic component mounting operation performed by the electronic component mounting apparatus according to the embodiment of the present invention. FIG. 6 is a process explanatory diagram of the electronic component mounting operation in the electronic component mounting method according to the embodiment of the present invention. FIG. 7 is an explanatory diagram of mounting height determination in the electronic component mounting method according to the embodiment of the present invention.
3 Substrate 8 Transfer Head 10 Suction Head 14 Suction Nozzle 15 Height Position Detection Unit 16 Vacuum Valve 17 Vacuum Pump 18 Contact Member 19 Probe 20 Conduction Detection Unit

Claims (2)

An electronic component mounting method in which an electronic component is picked up from a component supply unit by a mounting head equipped with a suction nozzle and mounted on a substrate, and the electronic component held by the suction nozzle is landed on the substrate by lowering the mounting head In the component mounting operation to be performed, the component contact timing when the electronic component contacts the substrate is detected by the contact detection means provided in the mounting head, and vacuum suction is performed from the suction nozzle based on the component contact timing. A vacuum suction means and / or a lifting means for raising and lowering the mounting head ;
The contact detection means includes a contact member provided in a nozzle holder provided in the mounting head, a probe provided to face the upper surface of the contact member, and the contact member and the probe connected to each other. The continuity detection unit, and when the upward force acts on the lower end portion of the suction nozzle, the continuity detection unit detects that the contact member and the probe are in contact with each other. A method of mounting an electronic component, wherein the detected electronic component is detected as contacting the surface of the substrate . It obtains the height position of the suction nozzle in the component contact timing on the basis of the detected parts contact timing by the abutment detection means, normal height position range previously stored look et the height 2. The electronic component mounting method according to claim 1, wherein the component mounting operation is continuously executed only when the height position is within a normal height position range.

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