The present invention relates to an electronic component mounting apparatus and electronic component mounting method for mounting electronic components of, for example, semiconductor bare chips, electronic circuit packages and the like on a board.
Conventionally, in mounting an electronic component such as a semiconductor bare chip with bumps on a board, there has been adopted a method for bonding the bumps to electrodes on the board by applying a load to the electronic component against the electrodes. According to this method, it is required to control the value of the load applied to each bump within a prescribed range, and therefore, mounting of the electronic component has been carried out while measuring the load applied to the electronic component by means of a load sensor such as a load cell.
The lower end portion of the first movement block 110 is provided with a shaft 113 whose central axis is arranged in the Z-direction and a holding head 115 for sucking and holding an electronic component 101 by a negative pressure, in this order. Moreover, a table 140 movable in an X-direction and a Y-direction is provided below the holding head 115, and a board 102 is placed on the table 140. An output of the load cell 130 is inputted to a control section 160, and the control section 160 controls the driving of the motor 150 while monitoring the output of the load cell 130.
When mounting the electronic component 101 on the board 102, the motor 150 is rotationally driven in a prescribed direction to move down the second movement block 120 and the first movement block 110 in the Z-direction. When the electronic component 101 is brought in contact with the board 102, the load detected by the load cell 130 gradually increases, and the electronic component 101 is pressurized. At this time, by applying, for example, ultrasonic waves while pressurizing the electronic component 101 with a prescribed load, bumps 101a provided at the bottom of the electronic component 101 are connected to the wiring pattern on the board 102 and then mounted. Subsequently, the holding head 115 is separated from the electronic component 101, and the second movement block 120 and the first movement block 110 are moved up in the Z-direction.
As a prior art relevant to the conventional electronic component mounting apparatus, Japanese unexamined patent publication No. 10-163273 discloses an electronic component mounting apparatus in which the first movement block and the second movement block are joined together via an air cylinder instead of joining the first movement block and the second movement block together by means of a spring. Japanese unexamined patent publication No. 08-203966 discloses an electronic component mounting apparatus in which a voicecoil motor is employed in place of the motor and screw feed mechanism in order to move the movement block in the Z-direction, and the holding head is attached to a shaft driven in the Z-direction by the voicecoil motor. Further, in Japanese unexamined patent publication No. 08-203966, a pressurizing force is estimated from a current applied to the voicecoil motor using no load sensor like the load cell.
Japanese unexamined patent publication No. 11-297764 discloses an electronic component mounting apparatus in which the electronic component and the board surface are made parallel to each other by detecting a pressure during bonding by means of load sensors provided in a plurality of places on the holding head side and adjusting the inclination of the lower surface of the holding head so that the value of the pressure becomes uniform.
Japanese unexamined patent publication No. 04-94553 discloses an electronic component mounting apparatus in which, in a bonding device for carrying out bonding by pressurizing a tape board against an electronic component placed on a table with the bumps directed upward, the inclination of the table is adjusted so that the pressurizing surface of the bonding tool and the bonding surface of the electronic component become parallel to each other on the basis of pressurizing forces detected by strain gauges provided in a plurality of places of the bonding tool that holds the tape board. Japanese unexamined patent publication No. 04-223349 discloses an electronic component mounting apparatus in which the inclination of a stage is adjusted on the basis of outputs of load sensors provided in a plurality of places of a table. Further, Japanese unexamined patent publication No. 04-223349 discloses a technique for making the pressurizing force of the bonding tool coincide with the pressurizing pattern by carrying out feedback control on the basis of an output of another load sensor provided for the bonding tool.
In the conventional electronic component mounting apparatus 100 shown in
Moreover, since only the load in the Z-direction is detected by the load cell 130 in the electronic component mounting apparatus 100, if the electronic component 101 is inclined with respect to the surface of the board 102, then the load is not uniformly applied to the bumps 101a at the bottom of the electronic component 101, possibly causing the contact failure of some bumps and the collapse of some bumps. Such an issue occurs similarly in the electronic component mounting apparatus of Japanese unexamined patent publication No. 10-163273. Moreover, the load applied to the electronic component is detected only in the Z-direction also in the electronic component mounting apparatus of Japanese unexamined patent publication No. 08-203966, and the measurement is carried out indirectly. Accordingly, there are the possibilities of the contact failure between the electronic component and the board, the collapse of bumps and the damage of the electronic component itself.
In the electronic component mounting apparatuses of Japanese unexamined patent publication Nos. 11-297764, 04-94553 and 04-223349, it is possible to detect the inclination of the electronic component and the board by means of a plurality of load sensors arranged in the horizontal detection. However, it is required to separately provide the load sensors in a plurality of places of the apparatus in order to appropriately measure the load. Conversely, if the load sensors are separated from the mounting position, regions occupied by the load sensors are disadvantageously increased. That is, according to the technique of arranging the plurality of load sensors in the horizontal direction, there is a limit to the accuracy of the sensor sections in detecting the inclination of the electronic component with respect to the board surface, and it becomes difficult to accurately detect the mounting failure.
Moreover, in order to remove the above issue that when the electronic component 101 is inclined with respect to the surface of the board 102, the load is not uniformly applied to the bumps 101a at the bottom of the electronic component 101, possibly causing the contact failure of some bumps and the collapse of some bumps, it is possible to use, for example, an air bearing in order to reduce the sliding resistance when the movement block is moved in the Z-direction. However, although the load can be supported by the air bearing when the load applied to the electronic component is small (e.g., about 300 gf), the air bearing cannot be used when a load that exceeds a prescribed limit is applied. Such the issue occurs similarly in the electronic component mounting apparatus of Japanese unexamined patent publication No. 10-163273.
In the electronic component mounting apparatus of Japanese unexamined patent publication No. 08-203966, the holding head is moved while being attached to the shaft driven in the Z-direction by the voicecoil motor, and therefore, a sliding resistance is generated similarly to the case of
Likewise, in the electronic component mounting apparatuses of Japanese unexamined patent publication Nos. 11-297764, 04-94553 and 04-223349, the load applied-to the electronic component is indirectly measured by an inclination adjustment mechanism or the like, and therefore, it is difficult to accurately measure the load actually applied to the electronic component. Therefore, it is difficult to accurately carry out the adjustment of the inclination of the electronic component with respect to the board surface on the basis of outputs from the load sensors, and there is a limit to the prevention of the mounting failure of the electronic component with an improvement in accuracy. Moreover, it is required to separately provide load sensors in a plurality of places of the apparatus in order to improve the measurement accuracy of the load, and it is difficult to detect the load in the neighborhood of the mounting position.
The present invention has been accomplished to solve the aforementioned conventional issues and has an object to provide an electronic component mounting apparatus capable of accurately detecting the mounting failure of the electronic component by detecting the load in the neighborhood of the mounting position.
Another object of the present invention is to solve the aforementioned conventional issues and provide an electronic component mounting apparatus capable of accurately measuring the load actually applied to the electronic component by eliminating the influence of an error due to sliding resistance when the movement block moves.
In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided an electronic component mounting apparatus for mounting an electronic component on a board, the apparatus comprising:
According to a second aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the first aspect, further comprising:
According to a third aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the first or second aspect, wherein
According to a fourth aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the third aspect, wherein
According to a fifth aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the first or second aspect, wherein
According to a sixth aspect of the present invention, there is provided an electronic component mounting method for mounting an electronic component on a board, the method comprising of:
According to a seventh aspect of the present invention, there is provided an electronic component mounting apparatus for mounting an electronic component on a board, the apparatus comprising:
According to an eighth aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the seventh aspect, further comprising:
According to a ninth aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the eighth aspect, further comprising:
According to a 10th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in any one of the seventh through ninth aspects, wherein
According to an 11th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the 10th aspect, wherein
According to a 12th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the 11th aspect, wherein
According to a 13th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in the 10th aspect, wherein
According to a 14th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in any one of the seventh through ninth aspects, wherein
According to a 15th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in any one of the seventh through ninth aspects, wherein
According to a 16th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in any one of the seventh through ninth aspects, wherein
According to a 17th aspect of the present invention, there is provided the electronic component mounting apparatus as defined in any one of the seventh through ninth aspects, wherein
According to an 18th aspect of the present invention, there is provided an electronic component mounting method for mounting an electronic component on a board, the method comprising of:
These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:
Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
Embodiments of the present invention will be described in detail below on the basis of the drawings.
The present invention is related to an electronic component mounting apparatus capable of accurately detecting the mounting failure of an electronic component by detecting the load in the neighborhood of the mounting position and accurately measuring a load applied to the electronic component by eliminating the influence of the sliding resistance of a guide mechanism with a load sensor provided in the neighborhood of a holding head. An electronic component mounting apparatus according to one embodiment of the present invention will be described below with reference to the drawings.
In the electronic component mounting apparatus 10, a nut section 21 provided in a movement block 20 that moves in the Z-direction is meshed with a feed screw 51 that is rotationally driven by a motor 50. A slider 11 is provided on a side surface of the movement block 20 and slides on a guide rail 12 directed in the Z-direction. The slider 11 and the guide rail 12 serve as a guide mechanism for movably guiding the movement block 20 in the mounting direction of the electronic component 1. Moreover, the motor 50, the feed screw 51 and the nut section 21 of the movement block 20 constitute a drive mechanism for driving the movement block 20 in the mounting direction of the electronic component 1.
At the lower end portion of the movement block 20 are provided a shaft 13 whose central axis is arranged in the Z-direction, a load sensor 30 that has a piezoelectric element for measuring the load applied to the electronic component 1, a block 141 to which a ultrasonic vibrator 14 is attached, and a holding section 15 for sucking and holding the electronic component 1 by a negative pressure, which are arranged in this order. The holding section 15, the block 141, and members provided between the holding section 15 and the block 141 are assembled as a holding head 15a that is an integrated block of high rigidity. Piping 16 connected to a vacuum pump (not shown) is connected to the holding section 15, and the electronic component 1 is sucked by carrying out suction from a suction port formed on the lower surface of the holding section 15. An optical system (optical interference system) linear scale 70, which is a displacement sensor for detecting the displacement amount in the Z-direction of the holding head 15a (mounting direction of the electronic component 1), is provided on the (+X) side of the shaft 13. Outputs of the linear scale 70 and the load sensor 30 are inputted to a control section 60.
A table 40, which can be moved in the X-direction and the Y-direction, is provided below the holding head 15a, and the board 2 is placed and held on the table 40. It is to be noted that a mechanism for feeding the electronic component 1 and a camera for detecting the relative position of the electronic component 1 with respect to the board 2 and so on are not shown in the figures.
In the load sensor 30, flat-plate-shaped three piezoelectric elements 31, 32 and 33 are stacked in layers in the Z-direction (mounting direction of the electronic component 1). For example, the direction of polarization of the piezoelectric element 31 located in the uppermost layer is determined so that a voltage is generated upon receiving a load (load in the direction perpendicular to the board 2, hereinafter referred to as a “vertical load”) in the direction roughly parallel to the mounting direction of the electronic component 1 (Z-direction shown in
The load sensor 30 has an attachment face 30b to which the holding head 15a is directly attached and another attachment face 30c that is parallel to the attachment face 30b and attached to the shaft 13 of the movement block 20. With this arrangement, it is achieved to attach to and detach the load sensor 30 and from the shaft 13 by means of one bolt 35 easily in a prescribed posture.
Next, the motor 50 is rotationally driven in a prescribed direction to move down the holding section 15 together with the movement block 20 in the (−Z)-direction (step S14), so that the electronic component 1 is brought in contact with the board 2. The contact of the electronic component 1 with the board 2 is accurately detected by a contact detection section 61 of the control section 60 shown in
When the contact of the electronic component 1 with the board 2 is detected in step S15, the driving of the movement block 20 is controlled by the control section 60 according to the load profile 601, and the pressurization of the electronic component 1 is started (step S16). Then, in a state in which the electronic component 1 is pressurized with a prescribed load as a consequence of a gradual increase in the load detected by the load sensor 30, the ultrasonic vibrator 14 is activated by a signal from the control section 60 to apply ultrasonic waves to the electronic component 1. Consequently, the bumps 1a provided at the bottom of the electronic component 1 are bonded to the wiring pattern on the board 2, so that mounting is carried out concurrently with placement (step S17)
Subsequently, a valve (not shown) provided for the piping 16 is opened with blow effected from the holding section 15 via the piping 16, and the holding section 15 is separated from the electronic component 1. Then, the motor 50 is rotationally driven in the reverse direction to move up the movement block 20 (and the holding head 15a) in the (+Z)-direction, completing the mounting of the electronic component 1 (step S18).
In the electronic component mounting apparatus 10, if some trouble occurs in the load applied to the electronic component 1 or the displacement of the electronic component 1 in mounting the electronic component 1 on the board 2 (steps S16 and S17), then the mounting failure (abnormality) of the electronic component 1 is detected by the control section 60 on the basis of outputs from the load sensor 30 and the linear scale 70.
First of all, if the contact of the electronic component 1 with the board 2 is detected and the pressurization of the electronic component 1 is started, then the load applied to the electronic component 1 is detected by the load sensor 30 and transferred to the control section 60 (step S21). The vertical load detected by the piezoelectric element 31 is compared with the load profile 601 stored in the storage section 62 to confirm whether or not the load is within the tolerance range (range between the lines 6021 located above and below the load profile 601) 602 of the load profile 601 shown in
If it is determined that the vertical load is outside the tolerance range 602 of the load profile 601 by a mounting failure detection section 63 (see
If it is determined that the vertical load is within the tolerance range 602 of the load profile 601, then the horizontal load detected by the piezoelectric elements 32 and 33 are next compared with the tolerance range of the horizontal load preparatorily stored in the storage section 62.
In the mounting failure detection section 63 of the control section 60, a position, in which the horizontal load values in the X-direction and the Y-direction detected by the load sensor 30 are served as the coordinate values, is compared with the tolerance range 603 (step S23). When the position is outside the tolerance range 603, the operator is informed of the detection of the mounting failure of the electronic component 1 by lighting the warning lamp 64 (step S30). As the case of the mounting failure detected in step S23, it can be considered, for example, the case where the electronic component 1 is held inclined with respect to the board 2 due to suction failure of the holding section 15, intrusion of a foreign object or the like and the case where a foreign object intrudes between some bumps 1a and the board 2.
In the electronic component mounting apparatus 10, the position in the space 604 that expresses the horizontal load applied to the electronic component 1 due to the intrusion of the foreign object 80 or the like is outside the tolerance range 603 when the position deviates not only in the (+X) direction but also in another direction, and the mounting failure is detected by the mounting failure detection section 63.
If it is determined that the horizontal load is within the tolerance range 603 by the mounting failure detection section 63, then it is confirmed whether or not the mounting of the electronic component 1 is ended by the control section 60 (step S24). If the mounting is not ended, the program flow returns to step S21 to repeat the measurement of the load and the detection of the mounting failure (steps S21 through S23) until the mounting of the electronic component 1 (pressurization of the electronic component 1 carried out in accordance with the load profile 601) ends (step S24).
If the mounting of the electronic component 1 is ended, then the displacement amount of the holding head 15a from the start of the mounting of the electronic component 1 (at the time of detection of the contact of the electronic component 1 with the board 2) to the end (end of the pressurization of the electronic component 1) is detected by the linear scale 70, transferred to the control section 60 (step S25) and compared with a displacement amount that becomes a reference (hereinafter referred to as a “reference displacement amount”) preparatorily stored in the storage section 62 (step S26).
If the detected displacement amount is outside the tolerance range preparatorily related to the reference displacement amount, then the operator is informed of the detection of the mounting failure of the electronic component 1 by lighting the warning lamp 64 by means of the mounting failure detection section 63, and the detection operation of the mounting failure ends (step S30). For example, if the electronic component 1 comes close to the board 2 more than necessary as a consequence of the collapse of the bump 1a of the electronic component 1 at the time of mounting or for another reason, then the detected displacement amount takes a great value outside the tolerance range, and such the mounting failure is detected by the mounting failure detection section 63.
Moreover, if the displacement amount detected by the linear scale 70 is within the tolerance range of the reference displacement amount, then it is determined that the placement (and mounting) of the electronic component 1 on the board 2 has been normally ended, and the detection operation of the mounting failure ends. As described above, in the electronic component mounting apparatus 10, by comparing the detection results of the load sensor 30 and the linear scale 70 with the tolerance range preparatorily stored in the storage section 62, the mounting failure of the electronic component 1 is detected by the mounting failure detection section 63. In the electronic component mounting apparatus 10, the mounting operation of the electronic component 1 is continued when the degree of the mounting failure is negligible even if the mounting failure is detected in steps S22 and S23, and the detection of the load and the displacement by the load sensor 30 and the linear scale 70 is continued until the mounting operation sequence ends, consequently obtaining the measurement results in the steps (steps S22, S23 and S26) for detecting the mounting failure.
In mounting the electronic component 1, a thermosetting anisotropic conductive resin film (ACF (Anisotropic Conductive Film)) (hereinafter referred to as an “ACF”) 2a is preparatorily stuck on the board 2, and the holding section 15 is preheated by the heat block 142. Therefore, when the electronic component 1 is held by the holding section 15, the electronic component 1 is heated via the holding section 15. Then, the holding section 15 is moved down to pressurize the electronic components 1 on the board 2 via the ACF 2a, and the conductive particles in the ACF 2a are collapsed to electrically bond the electrodes 1b of the electronic component 1 to the electrodes on the board 2. Concurrently with the bonding, the ACF 2a is heated and hardened via the electronic component 1, so that the electronic component 1 is fixed on the board 2. After the bonding ends, the holding section 15 releases suction and moves up.
Materials suitable for the piezoelectric element for the load sensor 30 will be described next. Table 1 shows relations between the materials of the piezoelectric element and various constants.
For example, the crystal, of which dielectric constant and piezoelectric distortion constant are low and the sensitivity is low, has high Curie point and excellent stability. Therefore, when the bonding is carried out by means of a heater as shown in
As described above, in the electronic component mounting apparatus 10, by detecting the horizontal load utilizing the piezoelectric elements 32 and 33 provided in a stack in the mounting direction of the electronic component 1 and detecting the vertical load utilizing the piezoelectric element 31 provided superposed on the piezoelectric elements 32 and 33, it is possible to reduce the size in the horizontal direction of the load sensor 30 and detect the load applied in the three directions to the electronic component 1 at the neighborhood of the mounting position of the electronic component 1. As a result, it is possible to more accurately measure the load applied to the electronic component 1.
Moreover, the load sensor 30 is directly attached to the holding head 15a that is the integrated block of high rigidity, and therefore, the load value detected by the load sensor 30 can be regarded as equivalent to the load applied to the electronic component 1. In particular, the load sensor 30 is arranged on the holding head 15a side with respect to the sliding portion of the slider 11 and the guide rail 12 in the Z-direction that is the mounting direction of the electronic component 1, and therefore, the load value detected by the load sensor 30 does not receive the influence of the sliding resistance between the slider 11 and the guide rail 12. Therefore, in comparison with the conventional electronic component mounting apparatus, a measurement value close to the real load actually applied to the electronic component 1 can be obtained, and the load applied to the electronic component 1 in mounting the electronic component 1 can be more accurately measured.
In the electronic component mounting apparatus 10, by comparing the vertical load applied to the electronic component 1 with the load profile 601 and detecting the deviation of the horizontal load applied to the electronic component 1 and/or the abnormality in the displacement amount of the electronic component 1 at the time of mounting, the mounting failure at the time of mounting the electronic component 1 can be accurately detected. Then, by removing the board 2 of which the mounting failure is detected as a defective component from the mass production process, the occurrence of defective electronic equipment as a finished product can be prevented in advance.
In the electronic component mounting apparatus 10, it is acceptable to execute by the control section 60 feedback control of the motor 50 that pressurizes the electronic component 1 against the board 2 by driving the holding head 15a on the basis of the result of comparison between the measurement value of the vertical load detected by the load sensor 30 and the load profile 601. As described above, in the electronic component mounting apparatus 10, the vertical load applied to the electronic component 1 can be accurately measured. Therefore, accurate control of the motor 50 can be executed, and it becomes possible to make variations in the vertical load applied to the electronic component 1 fall within a range of several grams. As a result, the defective bonding of the electronic component 1 to the board 2, the damage of the bumps 1a and the electrodes 1b at the bottom of the electronic component 1, the damage of the electronic component 1 itself, or the like can be prevented from occurring.
In the electronic component mounting apparatus 10, the position, in which the horizontal load values in the X-direction and the Y-direction are served as the coordinate values in the two-dimensional space 604, is compared with the tolerance range 603 that is a circular or elliptic region centered around the origin of the two-dimensional space 604. That is, the tolerance range 603 is determined with respect to the synthetic vector of the weight vectors in the X-direction and the Y-direction, and therefore, the detection of the mounting failure can be carried out by taking the deviations of the load in the X-direction and the Y-direction comprehensively into account. Moreover, by virtue of the elliptic tolerance range 603, the major axis and the minor axis of the ellipse can be changed in correspondence with the configuration of the electronic component 1, a difference in sensitivity between the piezoelectric element 32 in the X-direction and the piezoelectric element 33 in the Y-direction, or the like, and the tolerance range 603 can be appropriately set.
The load sensor, which employs the piezoelectric element, has a wider measurable range of the load than that of the load cell that employs a strain gauge. Moreover, both the crystal and piezoelectric ceramics, which are the materials of the piezoelectric element, have almost no hysteresis of elastic deformation since they have higher rigidity and a smaller amount of deformation than the metallic elastic body that constitutes the load cell. Therefore, the load applied to the electronic component 1 can be more accurately measured. Furthermore, the load sensor, which employs the piezoelectric element, has a high response speed than when a load cell is employed. Therefore, the contact of the electronic component 1 with the board 2 can be more accurately detected, and the load applied to the electronic component 1 can be accurately measured even when the electronic component is mounted at high speed. Therefore, by employing the piezoelectric elements 31 through 33 for the load sensor 30, an electronic component mounting apparatus 10 of higher versatility can be provided.
In the electronic component mounting apparatus 10a, when the electronic component 1 held by the holding section 15 is mounted on the board 2 while being pressurized, the load applied to the board 2 (i.e., the load applied to the electronic component 1) is measured by the load sensor 30 arranged vertically below the holding section 15.
The mounting operation of the electronic component 1 by the electronic component mounting apparatus 10a is similar to that of the first embodiment. First of all, the board 2 is placed and held on the table 40, and the electronic component 1 sucked and held by the holding section 15 is moved down to the mounting position on the board 2, and the contact of the electronic component 1 with the board 2 is detected by the contact detection section 61 of the control section 60. Subsequently, the pressurization of the electronic component 1 is started in accordance with the load profile 601 (see
Even in the electronic component mounting apparatus 10a, the mounting failure of the electronic component 1 is detected by the mounting failure detection section 63 on the basis of the outputs from load sensor 30 and the linear scale 70 at the time of mounting the electronic component 1. The detection operation of the mounting failure is also similar to that of the first embodiment. First of all, the vertical load and the horizontal load are detected by the piezoelectric elements 31 through 33 of the load sensor 30 (
If the vertical load is within the tolerance range 602, then the position, in which the horizontal load values in the X-direction and the Y-direction are served as the coordinate values in the two-dimensional space 604 in which the X-direction and the Y-direction of the load are served as the X-axis and the Y-axis, is compared with the tolerance range 603 of the horizontal load (step S23). If the position is outside the tolerance range 603, the mounting failure of the electronic component 1 is detected (step S30). In the electronic component mounting apparatus 10a, the detection of the mounting failure is repeated until the mounting of the electronic component 1 ends (step S24).
If the mounting of the electronic component 1 ends, then the displacement amount in the Z-direction of the holding head 15a from the start to the end of the mounting of the electronic component 1 is detected by the linear scale 70 and compared with the reference displacement amount (steps S25 and S26). The mounting failure of the electronic component 1 is detected when the displacement amount falls outside the tolerance range of the reference displacement amount (step S30), and the detection operation of the mounting failure ends when the displacement amount falls within the tolerance range.
As described above, the electronic component mounting apparatus 10a is able to detect the load applied to the electronic component 1 at the neighborhood of the mounting position of the electronic component 1 while reducing the size in the horizontal direction of the load sensor 30 by means of the piezoelectric elements 31 through 33 provided in a stack in the mounting direction of the electronic component 1 similarly to the first embodiment. Moreover, the load sensor 30 is provided just under the mounting position of the electronic component 1 in the position in which the influence of the sliding resistance of the slider 11 and the guide rail 12 is not exerted, and therefore, the load applied to the electronic component 1 can be more accurately measured.
In the electronic component mounting apparatus 10a, by comparing the vertical load applied to the electronic component 1 with the load profile 601 or detecting the deviation of the horizontal load applied to the electronic component 1 and the abnormality in the displacement amount of the electronic component 1 at the time of mounting, the mounting failure at the time of mounting the electronic component 1 can be accurately detected. Furthermore, by comparing the deviation of the horizontal load with the tolerance range 603 appropriately set in correspondence with the configuration of the electronic component 1 and so on, the detection of the mounting failure can be carried out taking the deviations in the X-direction and the Y-direction comprehensively into account.
Moreover, by employing the piezoelectric elements 31 through 33 for the load sensor 30, the electronic component mounting apparatus 10a of higher versatility can be provided.
Although the embodiments of the present invention have been described above, the present invention is not limited to the aforementioned embodiments but allowed to be modified in a variety of ways.
For example, a ball spline may be employed as a mechanism for guiding the movement of the movement block 20. In this case, the direction of the electronic component may be made changeable by pivoting the entire ball spline around the central axis.
Moreover, although the piezoelectric element has been employed as the load sensor in the aforementioned embodiments, a load cell may be employed similarly to the conventional case depending on the magnitude of the load and the load detection accuracy. Even in the above case, a measurement value close to the real load actually applied to the electronic component can be obtained since no error component ascribed to the sliding resistance of the guide mechanism or the like is included in the load detected by the load sensor, and the load to be applied to the electronic component at the time of mounting the electronic component can be more accurately controlled.
The electronic component mounting apparatus can be utilized for various cases of mounting various electronic components. For example, it is acceptable to preparatorily mount (temporary bond) an electronic component to, for example, solder bumps on a board by means of the electronic component mounting apparatus and bond the electronic component to the board by melting and solidifying the solder by reflow in the next process. Moreover, it is acceptable to temporarily pressure-bond an electronic component onto a board on which a thermosetting resin film has been stuck and use the electronic component mounting apparatus for the main pressure bonding to be carried out separately with pressurization and heating.
The electronic component to be mounted by the electronic component mounting apparatus may be, for example, an electronic component other than a semiconductor light-emitting element of an LED chip, a semiconductor laser, or the like, a packaged IC, a fine semiconductor chip of a resistor, a capacitor, or the like, or an SAW (Surface Acoustic Wave) filter other than semiconductor. The board may be formed of a material of glass, semiconductor, or the like other than resin. The electronic component may be held in the mounting stage by a mechanical chuck or an electrostatic chuck besides the suction with a negative pressure of the aforementioned embodiments.
The present invention can be utilized for the electronic component mounting apparatus that mounts an electronic component on a circuit board.
According to the present invention, by detecting the horizontal load by means of the piezoelectric elements, the size in the horizontal direction of the load sensor can be reduced, and the load can be detected at the neighborhood of the mounting position. Moreover, the mounting failure of the electronic component can be accurately detected from the deviation of the horizontal load. According to the second aspect of the present invention, the mounting failure of the electronic component can be accurately detected from the vertical load.
According to the third aspect of the present invention, the tolerance range corresponding to the load profile can be set for the horizontal load. According to the fourth aspect of the present invention, the mounting failure can be detected by taking the deviations of the load in the X-direction and the Y-direction comprehensively into account.
According to the present invention, the load applied to the electronic component is measured by the load sensor provided between the movement block and the holding head. Therefore, the load applied to the electronic component at the time of mounting the electronic component can be more accurately measured without receiving the influence of the sliding resistance or the like due to the guide mechanism for guiding the movement block. According to the 10th aspect of the present invention, the load applied to the electronic component can be more accurately measured.
According to the eighth aspect of the present invention, the mounting failure of the electronic component can be accurately detected from the vertical load. According to the ninth aspect of the present invention, the mounting failure of the electronic component can be accurately detected from the deviation of the horizontal load. According to the 12th aspect of the present invention, the mounting failure of the electronic component can be accurately detected from the displacement amount of the electronic component.
According to the 17th aspect of the present invention, the load sensor can easily be attached and detached in a prescribed posture.
By properly combining the arbitrary embodiments of the aforementioned various embodiments, the effects possessed by the embodiments can be produced.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
Number | Date | Country | Kind |
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2003-157937 | Jun 2003 | JP | national |
2004-103755 | Mar 2004 | JP | national |
2004-103756 | Mar 2004 | JP | national |