JP4974982B2 - Mounting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solder jointing method controlling the height of molten solder between a mounting member and a mounted member to reduce a difference in final height between the members after solidification of the solder and a mounted member. <P>SOLUTION: In the solder jointing method of solidifying the molten solder (a solder bump 17a of a bumped bare IC 17) interposed between the bumped bare IC 17 as the mounting member and a substrate 18 as the mounted member to join the bumped bare IC 17 and the substrate 18, a load exerted onto the molten solder bump 17a between the bumped bare IC 17 and the substrate 18 is controlled to be a target load determined in advance from its desired height between the bumped bare IC 17 and the substrate 18 and the volume of the solder bump 17a. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention, the mounting member and with the molten solder intervening solidifying between the mounted member, to implement device you join the mounting member and the mounting member.

  In recent years, a technology for flip chip mounting a bumped bare IC in which solder bumps are respectively formed on a plurality of pads arranged on one main surface on a substrate has been developed. The construction method is known. As a typical bare IC with bumps, there are one in which pads (bumps) are arranged on the periphery of one main surface, and one in which pads (bumps) are arranged in a lattice pattern on one main surface. is there.

  FIG. 5 shows a configuration of a main part of a conventional component mounting apparatus for flip-chip mounting a bumped bare IC by a solder bonding method. The bumped bare IC as a mounting member is sucked and held, and the sucked and held bumped IC is attached. The configuration of a mounting head for mounting the bare IC with bumps on the substrate by bonding the solder bumps of the bare IC to the land of the substrate which is a mounted member held on the mounting stage is shown.

  In this conventional component mounting apparatus, as shown in FIG. 5, the bumped bare IC 204 is sucked and held by the suction nozzle 203 provided at the tip of the mounting head 202 that is moved up and down by the lifting drive unit 201, and the mounting head 202 is lowered. The solder bump 204a of the bare IC 204 with bumps held by suction at the front end surface of the suction nozzle 203 is brought into contact with a land (not shown) of the substrate 205, and bumps are made by the ceramic heater 206 provided on the back surface of the suction nozzle 203. After the solder ICs 204a are heated to melt the solder bumps 204a, a cooling air is blown from the blow nozzle 207 to the bare ICs 204 with bumps, and the melted solder bumps 204a are solidified and bonded to the lands of the substrate 205. The bare IC 204 is mounted on the substrate 205. The heat insulating portion 208 blocks heat so that the heat of the ceramic heater 206 does not transfer to the mounting head main body side.

  In addition, the tool including the suction nozzle 203, the ceramic heater 206, the blow nozzle 207, the heat insulating portion 208, and the support shaft 209 is thermally expanded by the heat of the ceramic heater 206, and the mounting stage is also transmitted through the bumped bare IC. When the bare IC 204 with bumps is cooled by the cooling air from the blow nozzle 207 while being thermally expanded by the heat of the heated ceramic heater 206, the thermally expanded tool and the mounting stage are contracted.

Therefore, in the conventional component mounting apparatus, when the thermal expansion amount and contraction amount of the tool and the mounting stage are predicted and the solder bump 204a is melted, the tool is raised according to the predicted thermal expansion amount, and the solder bump is When solidifying 204a, the tool is lowered in accordance with the predicted amount of contraction (see, for example, Patent Document 1).
JP 2005-353696 A

  As described above, in the conventional component mounting apparatus, the thermal expansion amount and the contraction amount of the mounting stage that holds the substrate that is the mounting member and the tool that holds the bumped bare IC that is the mounting member are predicted. The tool was moved up and down according to the predicted amount.

  However, as in the conventional component mounting apparatus described above, only by controlling the position of raising and lowering the tool by predicting the thermal expansion amount and contraction amount of the tool and the mounting stage, due to the influence of the ambient temperature and the temperature of the cooling air, Variations occur in the amount of expansion and contraction, resulting in variations in the final height (gap) between the bare IC with bumps after the solder bumps are solidified and the substrate. This variation hindered yield improvement.

In view of the above problems, the present invention controls the load applied to the molten solder interposed between the mounting member and the mounted member, so that the molten solder between the mounting member and the mounted member By controlling the height between the mounting member and the mounted member in an intervening state, it is possible to suppress the occurrence of variations in the final height (gap) between the mounting member and the mounted member after the solder is solidified. it is an object of the present invention to provide an implementation system Do that enables.

Mounting apparatus according to claim 1 of the present invention includes a movable portion for holding the mounting member, by elevating the elevating shaft, across a drive unit for vertical movement of the movable part on the elevator shaft and coaxially, the fulcrum On the other hand, on the same axis as the raising / lowering shaft of the drive unit, the movable part whose lifting operation is guided by an air bearing is supported, and on the other side, a weight is supported, and the fulcrum is the movable part. And a balance mechanism that compensates for gravity so as to cancel at least the weight in the weight direction of the movable part, and between the movable part and the drive part, the same axis as the lift axis of the drive part is disposed above the load detection unit for detecting a load applied to the solder interposed between the mounting member and the mounting member, said movable by the drive unit based on the load detected by the load detection unit Control to control the lifting and lowering of In the state where the mounting member held by the movable part and the mounted member are in contact with each other via the molten solder, the molten solder is cooled and solidified, wherein a mounting device for mounting the mounting member to be mounted member, said in a state where said mounting member and the mounting member is contacted via solder the melted, the load detected by the load detection unit as the objectives load, and controlling the vertical movement of the movable portion by the drive unit.

  According to a preferred embodiment of the present invention, the height of the molten solder interposed between the mounting member and the mounted member is controlled, and the final height between the mounting member and the mounted member after the solder is solidified. It is possible to suppress the occurrence of variation in the length (gap), and the yield can be improved.

Hereinafter, embodiments of the implementation apparatus according to the present invention will be described sprinkled with drawings. Here, a component mounting apparatus for mounting a bumped bare IC as a mounting member on a substrate as a mounted member will be described as an example. The invention is not limited to this example, implementation device of the present invention, the mounting member and with the molten solder intervening solidifying between the mounted member, applying a mounting member that equipment be joined to the mounted member can do. For example, the present invention can be applied to a case where a bumped bare IC is mounted on an IC substrate.

  FIG. 1 shows a configuration of a main part of a component mounting apparatus according to an embodiment of the present invention, in which a bare IC with bumps is held by suction, and solder bumps of the bare IC with bumps held by suction are held on a mounting stage. A configuration of a mounting head for mounting a bare IC with bumps on a substrate by bonding to a land (electrode) of the substrate is shown.

Of course, the mounting apparatus of the present invention is not limited to the configuration of the component mounting apparatus. Also, mounting device of the present invention is not limited to the component mounting apparatus for mounting a bare IC with bus amplifier.

  In FIG. 1, the moving body 1 is supported by a mounting head base 2 so as to be movable up and down. For example, the moving body 1 may be supported by the mounting head base 2 via a linear guide.

  The moving body 1 is driven in the vertical direction by a driving means (not shown). The driving means may be constituted by, for example, a motor provided on the mounting head base 2, a ball screw provided on the output shaft of the motor, a nut fixed to the moving body 1 and screwed to the ball screw. . With this configuration, the mounting head can be positioned in the vertical direction according to the rotation angle amount of the motor. In addition, the raising / lowering operation | movement of this mounting head is controlled by the control part 3 of a component mounting apparatus.

  On the other hand, the mounting head base 2 is supported so as to be movable in the horizontal direction by an XY movement mechanism (not shown). With this XY movement mechanism, the mounting head is held along the XY plane (horizontal plane) above the receiving position of the bumped bare IC supplied from the component supply unit (not shown) and by the mounting stage (not shown). It is transported between above the mounting position on the substrate 18. The parallel movement of the mounting head is controlled by the control unit 3 of the component mounting apparatus.

  With the above configuration, the mounting head moves above the receiving position of the bumped bare IC, holds the bumped bare IC 17 by suction and lifts, and then moves above the mounting position on the substrate 18 held by the mounting stage. The bare IC 17 with bumps can be mounted at the mounting position on the substrate 18 by the lifting and lowering operation.

  The lower part of the moving body 1 is a casing 4. A rotating member 6 is attached to the inside of the casing 4 via bearings 5a and 5b. A gear 7 is attached to the upper surface of the rotating member 6 with the center thereof aligned with the center of the rotating member 6. The gear 7 meshes with a gear 9 attached to the output shaft of a motor 8 attached to the ceiling portion of the casing 4. With such a configuration, the rotating member 6 is rotated with respect to the casing 4 (moving body 1) while being guided by the bearings 5a and 5b by the drive of the motor 8.

  The rotary member 6 has a concave portion 6a that opens downward, and the suction bit portion 10 is inserted into the concave portion (internal space of the rotary member 6) 6a. A first support shaft 11 a is attached to the lower end of the suction bit portion 10, and the tip (lower end) side of the first support shaft 11 a protrudes outward from a hole 12 a formed in the lower portion of the casing 4. Yes.

  A heating head 13, a heat insulating part 14, and a blow nozzle 15 are provided on the distal end side of the first support shaft 11 a protruding from the lower part of the casing 4. A nozzle 16 is attached to the heating head 13, and the upper surface of the bumped bare IC 17 is adsorbed to the tip of the nozzle 16. A plurality of pads (electrodes) (not shown) are formed on the lower surface of the bare bear IC 17 with bumps, and solder bumps 17a are respectively formed on these pads.

  In order to join the solder bump 17a of the bare IC 17 with bump and the land (not shown) of the substrate 18, first, the bare IC 17 with bump held by the nozzle 16 is heated by the heat generated by the heating head 13. Then, the solder bumps 17a are melted. Thereafter, by blowing cooling air from the blow nozzle 15 to the heated bare IC 17 with bumps, the bare IC 17 with bumps is cooled and the molten solder bumps 17a are solidified. The heat insulating portion 14 prevents heat from the heating head 13 from being transferred to the first support shaft 11a side. The heating operation of the heating head 13 and the operation of blowing cooling air from the blow nozzle 15 are controlled by the control unit 3 of the component mounting apparatus.

  In the present embodiment, the hole 12a is arranged such that the outer peripheral portion of the lower end of the suction bit portion 10 that moves up and down with respect to the moving body 1 (casing 4) contacts the inner wall surface of the casing 4 around the hole 12a. The inner wall surface of the casing 4 around the hole 12a is used as a stopper.

  An annular air supply chamber 19 is formed on the inner periphery of the casing 4, and the air supply chamber 19 is connected to an air supply hole 20 that opens to the outer surface of the casing 4. Corresponding to the annular air supply chamber 19, the rotary member 6 is formed with a plurality of air supply holes 21 communicating with the recess (internal space) 6a. Between the inner peripheral surface of the casing 4 and the outer peripheral surface of the rotating member 6, an air seal 22 a as a sealing means is provided so that air can be sent from the annular air supply chamber 19 to the air supply hole 21 of the rotating member 6 in an airtight state. 22b are arranged apart from each other in the vertical direction. Here, O-rings are used as the air seals 22a and 22b, but they can also be configured by Y packing.

  With the above configuration, the air supplied from the open end of the air supply hole 20 disposed on the outer surface of the casing 4 is supplied to the airtight area of the air supply chamber 19 sandwiched between the air seals 22a and 22b. From the airtight area of the rotating member 6 to the gap between the inner peripheral surface of the rotating member 6 and the outer peripheral surface of the suction bit portion 10 through the air supply hole 21 of the rotating member 6. An air bearing is formed between them. With this air bearing, it is possible to support the suction bit portion 10 with respect to the moving body 1 so as to be movable up and down.

  As shown in FIG. 1, an air holding chamber 21 a that covers the entire periphery of the rotating member 6 may be provided in the middle of the air supply hole 21. The air holding chamber 21 a has a larger cross-sectional area than the opening end inside the air supply hole 21 (on the suction bit portion 10 side), and ensures a stable pressure between the rotating member 6 and the suction bit portion 10. it can.

  A second support shaft 11 b is connected to the upper end of the suction bit portion 10, and the second support shaft 11 b includes a hole 12 b formed in the upper part of the rotating member 6, and a hole 12 c formed in the gear 7. Then, it extends outside the casing 4 through the hole 12d formed in the ceiling portion of the casing 4, and is inserted into a recess (internal space of the holder portion 23) 23a that opens below the holder portion 23. The holder portion 23 supports the second support shaft 11b via the bearing 24 so as to be rotatable.

  In the above configuration, the concave section 6a of the rotating member 6 has a quadrangular horizontal cross-sectional shape, and the suction bit portion 10 that engages the concave section 6a with a gap for air bearings also has a quadrangular horizontal sectional shape. The suction bit unit 10, the support shafts 11a and 11b, the heating head 13, the heat insulating unit 14, the blow nozzle 15 and the nozzle 16 can be rotated together with the rotation of the member 6. Therefore, based on the output of an encoder (not shown) that detects the rotation angle of the output shaft of the motor 8, the control unit 3 of the component mounting apparatus causes the output shaft of the motor 8 to rotate by a predetermined angle amount. By controlling the rotational drive of the motor 8, it is possible to adjust the orientation of the bare IC 17 with bumps held by suction at the tip of the nozzle 16.

  In addition, the horizontal cross-sectional shape of the recessed part 6a of the rotation member 6 and the adsorption | suction bit part 10 is not limited to a rectangle, The horizontal cross-sectional shape of the recessed part 6a of the rotation member 6 and the adsorption | suction bit part 10 should just be a polygonal shape. . Further, the recess 6a of the rotating portion 6 and the horizontal cross-sectional shape of the suction bit portion 10 may both be circular, and a protrusion engaging with a groove provided on the other of the rotating member 6 and the suction bit portion 10 may be formed.

  In addition, although an air bearing is configured between the rotating member 6 and the suction bit portion 10, a linear guide such as a ball spline bearing is disposed between the rotating member 6 and the suction bit portion 10, so that the rotating member 6 It is good also as a structure which supports the adsorption | suction bit part 10 through a linear guide so that an up-down movement is possible. FIG. 2 shows a configuration in which a ball spline bearing 41 is disposed between the rotating member 6 and the suction bit portion 10.

  Air suction holes 25 are formed in the suction bit portion 10, the support shafts 11 a and 11 b, the heating head 13, the heat insulating portion 14, the blow nozzle 15, and the nozzle 16. The air suction hole 25 opens at the tip of the nozzle 16 and the upper end of the second support shaft 11 b and communicates with the recess 23 a of the holder portion 23. In addition, the holder portion 23 is formed with an air suction hole 26 communicating with the internal space (recess 23a), and a vacuum generator (not shown) is connected to the opening end outside the air suction hole 26. . In addition, an air seal 27 is disposed between the outer peripheral surface of the second support shaft 11b and the inner peripheral surface of the holder portion 23 as sealing means for making the inner space of the holder portion 23 airtight. Since it comprised in this way, the front-end | tip of the nozzle 16 can be evacuated with a vacuum generator, and the bare IC 17 with a bump can be adsorb | sucked to the front-end | tip of the nozzle 16. FIG.

  In addition, although an O-ring is used as the air seal 27 here, it can also be comprised with Y packing. Further, the position of the opening end of the air suction hole 25 on the holder portion 23 side is not limited to the upper end of the second support shaft 11b. The opening end of the air suction hole 25 on the holder portion 23 side may be provided at a position where the tip of the nozzle 16 and the internal space of the holder portion 23 can communicate with each other, and is provided on the outer peripheral surface of the second support shaft 11b. Also good. Moreover, it is not limited to the structure which attracts | sucks air from the opening end of the air suction hole 25 formed in the 2nd support shaft 11b, for example, sucks air from the outer surface of the mobile body 1 (casing 4), A vacuum is generated at the tip of the nozzle via the gap between the inner surface of the moving body 1 (casing 4) and the outer surface of the rotating member 6 and the gap between the inner surface of the rotating member 6 and the outer surface of the suction bit portion 10. A configuration may be adopted. In this case, the flow rate of the air to be sucked is made larger than the flow rate of the air supplied to constitute the air bearing.

  A third support shaft 11 c is connected to the upper surface of the holder portion 23. As described above, since the third support shaft 11c is connected to the upper surface of the holder portion 23 that rotatably supports the second support shaft 11b, the third support shaft 11c responds to the rotation of the rotating member 6. Even if the suction bit unit 10 or the like rotates, it does not rotate.

  The upper end of the third support shaft 11 c is connected to the pressure sensitive part of the load cell 29 via the compression spring 28. When the suction bit unit 10 is in contact with the stopper of the moving body 1 (casing 4), the load cell 29 detects a load applied to the stopper by driving a voice coil motor, which will be described later. When the solder bump 17a of the bumped bare IC 17 adsorbed to the tip of the nozzle 16 is in contact with the land of the substrate 18, the bare IC 17 with bump is driven by driving a voice coil motor described later. The load applied to is detected.

  In the present embodiment, as will be described later, a load obtained by dividing the load applied to the bare IC 17 with bumps by the number of the solder bumps 17a by driving the voice coil motor is applied to each solder bump 17a. It becomes a load. That is, in the present embodiment, the load cell 29 realizes a load detection unit that detects a load applied to the solder bump 17a.

  The compression spring 28 is for protecting the load cell 29. Here, the compression spring is used as a protection means for the load cell. However, it is only necessary to have a mechanism capable of protecting the load cell when a high load is applied thereto, and the means for protecting the load cell is not limited to the compression spring.

  The moving body 1 is provided with a voice coil motor (hereinafter referred to as VCM) 30 that drives the load cell 29 in the vertical direction with respect to the moving body 1. The VCM 30 includes a rod 31, a magnet 32 attached to the rod 31, and a coil 33 provided on the peripheral side of the magnet 32. The casing of the VCM 30 is fixed to a first holding part 34 a provided on the moving body 1. The first holding portion 34a supports the rod 31 so as to be slidable in the axial direction. In such a configuration, the rod 31 can be driven in the vertical direction by controlling the current flowing through the coil 33.

  The rod 31 is connected to the surface of the load cell 29 opposite to the pressure-sensitive portion, and the load cell 29 also moves up and down according to the lifting and lowering operation of the rod 31. Therefore, according to the raising / lowering operation of the rod 31, the adsorption | suction bit part 10 and the movable parts which consist of the support shafts 11a-11c, the heating head 13, the heat insulation part 14, the blow nozzle 15, the nozzle 16, and the holder part 23 also raise / lower. . As described above, in the present embodiment, the VCM 30 is provided as a drive unit that moves the movable unit that holds and holds the bumped bare IC 17 that is a mounting member.

  The operation of the VCM 30 is controlled by the control unit 3 of the component mounting apparatus. Specifically, the control unit 3 passes a current based on a deviation between a detected value of the load cell 29 and a set load described later through the coil 33 of the VCM 30 and passes the rod 31 so that the detected value of the load cell 29 becomes the set load. Then, the load cell 29 is moved up and down.

  The configuration for controlling the operation of the VCM is not limited to this. For example, a position detector that detects the position of the rod of the VCM is mounted on the VCM main body, and the deviation between the detected value of the load cell and the set load is calculated. It is good also as a structure which converts into the target position of a rod and operates a rod so that the detected value of a position detector may become a target position. In addition, here, a case where a VCM is used to move the load cell up and down will be described. However, the present invention is not limited to this. For example, a linear motor or a cylinder may be used instead of the VCM.

  In the present embodiment, the oscillating body 35 is engaged with the third support shaft 11c on one side of the fulcrum, and is engaged with a balance weight (weight) 36 on the other side. A bearing 38 supported by a support base 37 fixed to the moving body 1 is disposed at the fulcrum, and the bearing 38 supports the swinging body 35 so as to be swingable.

  The balance mechanism composed of the oscillating body 35, the balance weight 36, and the bearing 38 is engaged with the movable portion to compensate the total weight of the movable portion and the bare IC 17 with bumps held by the movable portion. Thus, a balance mechanism that generates a force corresponding to the total weight is configured.

  By providing such a balance mechanism, the total weight of the movable part and the bumped bare IC 17 attracted and held by the movable part is compensated, so that the VCM 30 is driven to be applied to the bumped bare IC 17. A load obtained by dividing the load by the number of solder bumps 17a is a load applied to each solder bump 17a.

  Further, by providing the balance mechanism, it is possible to reduce the impact force applied to the pressure sensitive part of the load cell when the bumped bare IC is brought into contact with the substrate. Therefore, a load cell with high resolution capable of detecting a minute force can be used, and even when the load applied to the bare IC with bumps is low by driving the VCM, the load can be accurately detected. Thus, it becomes possible to mount the bare IC with bumps on the substrate with a low load. For example, the load applied to the bare IC with bumps can be maintained at about 1 gf.

  In addition, the structure which the rocking | fluctuation body 35 engages with the 3rd support shaft 11c should just be a structure which does not become the obstacle of the vertical movement of the 3rd support shaft 11c. Further, here, a balance weight (weight) is used to compensate the total weight of the movable part and the bumped bear IC 17 attracted and held by the movable part, but a constant force that can be arbitrarily set is generated. It is not limited to the weight as long as it can be done. That is, it is only necessary to generate a force corresponding to the total weight of the movable part and the bumped bear IC 17 attracted and held by the movable part to compensate the total weight.

  Further, when the influence of the weight of the bare IC 17 with bumps on the impact force applied to the pressure sensitive part of the load cell 29 when the bare IC 17 with bumps is brought into contact with the substrate 18, only the weight of the movable part is compensated. It may be. In this case, a load obtained by adding the weight of the bumped bare IC 17 to the load given to the bumped bare IC 17 by driving the VCM 30 and dividing the load by the number of solder bumps 17a is given to each solder bump 17a. Load.

  As described above, the component mounting apparatus supports the movable portion on one side across the fulcrum and the balance weight on the other side as a gravity compensation mechanism for compensating for gravity so as to cancel the weight of the movable portion in the gravity direction. A balance mechanism for supporting the (weight) 36 is provided.

  In the present embodiment, a tension spring 39 is provided as an urging means for increasing the load applied to the VCM 30. One end of the tension spring 39 is engaged with the second holding portion 34 b provided on the movable body 1, and the other end is engaged with the holding member 40 that holds the load cell 29.

  Therefore, the load detected by the load cell 29 is the difference between the load applied by the VCM 30 to the rod 31 and the tensile load of the tension spring 39. Therefore, for example, when the tensile load of the tension spring 39 is 200 gf, the VCM 30 applies a downward load of 202 gf to the rod 31 when the load applied to the bumped bare IC 17 is controlled to about 2 gf. By doing so, the load detected by the load cell 29 is 2 gf, and the load applied to the bare IC 17 with bumps can be 2 gf.

  As described above, in the VCM 30, it is necessary to generate a force that cancels the tensile load by the tension spring 39. Therefore, even when the load applied to the bumped bare IC 17 is small, the amount of current flowing through the coil 33 of the VCM 30 can be increased. it can. Therefore, the responsiveness of the VCM 30 can be improved, and a minute load can be controlled with high accuracy.

  With the configuration described above, the movable body 1 can support the movable portion so as to be movable up and down. Further, by controlling the current flowing through the coil 33 of the VCM 30, the rod 31 connected to the surface (upper surface) opposite to the pressure-sensitive portion of the load cell 29 is driven in the vertical direction so that the stopper and the nozzle 16 The load applied to the bare IC 17 with bumps held by suction can be controlled.

  The operation of the VCM 30 is controlled based on the load detected by the load cell 29 by the control unit 3 of the component mounting apparatus. Specifically, the control unit 3 controls the lifting and lowering operation of the movable unit by the VCM 30 so that the load detected by the load cell 29 becomes a set load obtained in advance. That is, force control is performed.

  As described above, in the present embodiment, by providing the balance mechanism, the load applied to the bare IC with bumps can be controlled to a low value. Therefore, since the force control can be performed even when the solder bump 17a is melted, the height of the melted solder bump can be controlled by the force control, as will be described later.

  The set load described above is obtained in advance from the desired height between the bare IC 17 with bumps and the substrate 18, the volume of the solder bumps 17a, the number of solder bumps 17a, and the land area of the substrate 18 (area of the solder bump mounting region).

  Specifically, for each combination of the volume of solder (solder amount) interposed between the mounting member and the mounted member and the area of the region on which the solder is mounted (solder mounting region), A result of simulating the relationship between the height of the melted solder interposed between the mounting member and the mounted member and the load applied to the melted solder is stored in advance in a storage area (not shown), and the controller 3 However, the load to be applied to each solder bump using the result of the above simulation with the desired height between the bare IC 17 with bump 17 and the substrate 18, the volume of the solder bump 17a, and the land area of the substrate 18 as parameters. (Target load) is obtained, and the set load is obtained by multiplying the target load by the number of solder bumps 17a.

  In the present embodiment, as described above, the balance mechanism compensates for the total weight of the movable part and the bare IC with bump held by the movable part, so that the target to be given per solder bump A value obtained by multiplying the load by the number of solder bumps is set as the set load.

  The volume of the solder bump 17a of the bare IC 17 with bump can be obtained from the shape data of the solder bump 17a. For example, it can be obtained by calculation from the height and radius of the solder bump disclosed by the manufacturer of the bare IC 17 with bump. Alternatively, the height and radius of the solder bump 17a may be measured and obtained from the measured values by calculation. Alternatively, the height and radius of the solder bump 17a or the volume of the solder bump 17a may be obtained from the method of forming the solder bump 17a. For example, when the solder bumps 17a are formed by a plating method, the height and radius of the solder bumps 17a deposited on the pads or the solder bumps 17a are determined from the thickness of the photoresist and the diameter of the pads exposed from the photoresist. The volume can be determined.

  Therefore, for example, the control unit 3 calculates the volume of the solder bump 17a based on the solder bump shape data such as the height and radius of the solder bump 17a input from an input unit such as a keyboard (not shown). It may be configured to store in a storage area (not shown), or the volume of the solder bumps 17a input from an input unit such as a keyboard (not shown) may be stored in the storage area (not shown).

  Moreover, the land area of the board | substrate 18 can be calculated | required by calculation from the land radius which the manufacturer of the board | substrate 18 discloses, for example. Or the radius of the land of the board | substrate 18 may be measured, and it may obtain | require by calculation from the measured value, and the area of the land of the board | substrate 18 may be measured.

  Therefore, for example, the control unit 3 may calculate a land area based on a land radius input from an input unit such as a keyboard (not shown), and store the calculation result in a storage area (not shown). The land area input from the input unit such as the control unit 3 may be stored in a storage area (not shown).

  The number of solder bumps 17a of the bare IC 17 with bumps may be, for example, the number of solder bumps disclosed by the manufacturer of the bare IC 17 with bumps, or the number of solder bumps 17a may be measured.

  When only the weight of the movable part is compensated by the balance mechanism, a value obtained by subtracting the weight of the bumped bare IC from the value obtained by multiplying the target load per solder bump by the number of solder bumps is set. It may be set as a load, or when the influence of the weight of the bumped bare IC on the control of the height of the melted solder bump is small, the target load to be applied per solder bump is multiplied by the number of solder bumps The value obtained may be set as the set load.

  As described above, the control unit 3 automatically sets the target based on the desired height between the bumped bare IC 17 and the substrate 18 input from the input unit, the shape data of the solder bumps 17a, the number of the solder bumps 17a, and the like. Calculate the load and set load. By applying the calculated set load to the bare IC 17 with bumps, the target load can be applied to the solder bumps 17a.

  Next, an example of the above simulation will be described. In this simulation, the model is melted solder interposed between a pad (solder mounting area on the mounting member side) and a land (solder mounting area on the mounted member side).

  FIG. 3 shows a longitudinal sectional view of an example of a solder model used in this simulation. As shown in FIG. 3, in this simulation, the longitudinal sectional shape of the side surface 103 a of the molten solder 103 interposed between the circular pad 101 and the circular land 102 becomes an arc shape, and the load on the solder 103 is reduced. In the initial state of “0”, the center point of the circular arc is located at the center of the solder 103, and as the load on the solder 103 increases from the initial state to the positive side, the center point of the circular arc is “b”. By shifting to the arc side, the radius R of the arc is reduced and the height of the solder 103 (the height between the pad 101 and the land 102) h is reduced, while the load on the solder 103 is shifted from the initial state to the negative side. As the number increases, the center point of the arc moves away from the arc side by 'b', the radius R of the arc increases, and the height of the solder 103 (the height between the pad 101 and the land 102) h increases. It is assumed that becomes model.

  In FIG. 3, “a” is the distance between the center of the solder 103 and the pad 101 or the land 102, and is half the height h of the solder 103. “Ro” is the radius of the land 102. In this simulation, it is assumed that the radii of the pad 101 and the land 102 are equal. That is, it is assumed that the pad area (the area of the solder mounting area on the mounting member side) and the land area (the area of the solder mounting area on the mounted member side) are equal.

  As described above, as the load increases to the positive side, the radius R of the arc of the side surface 103a of the solder 103 decreases, and the height of the solder 103 (the height between the pad 101 and the land 102) h decreases. Assuming a model, the radius R of the arc of the side surface 103a of the solder 103 and the volume V of the solder 103 can be calculated using equations with (ro, a, b) as variables.

  In this simulation, the load applied to the molten solder interposed between the pad and the land is obtained based on the Young Laplace equation. Specifically, as described above, the longitudinal cross-sectional shape of the side surface 103a of the melted solder 103 is an arc shape having a radius R, and therefore the pressure difference ΔP between the external pressure and the internal pressure on the side surface 103a is used as the variable. Obtained from Young Laplace's equation. Further, as described above, the radius R decreases as the load on the solder 103 increases to the positive side, so that the pressure difference between the external pressure and the internal pressure when the load on the solder 103 is “0” is ΔPo. Then, as the load on the solder 103 increases from the initial state to the positive side, the pressure difference ΔP between the external pressure and the internal pressure on the side surface 103a increases from ΔPo, and as the load on the solder 103 increases from the initial state to the negative side. The pressure difference ΔP between the external pressure and the internal pressure on the side surface 103a decreases from ΔPo. Therefore, an increase / decrease value “ΔP−ΔPo” from the pressure difference ΔPo in the initial state is calculated, and an area of the upper surface of the solder 103, that is, a pad area (here, equal to a land area having the radius ro as a variable) is calculated. By multiplying, the load applied to the molten solder is obtained.

  As described above, the pressure difference ΔP can be calculated by an expression using the radius R as a variable, and the radius R can be calculated by an expression using (ro, a, b) as a variable. The applied load can also be calculated by an expression having (ro, a, b) as variables.

  As described above, the volume V of the melted solder interposed between the pad and the land and the load applied to the melted solder can be calculated by an expression having (ro, a, b) as variables. Therefore, by giving the land radius ro and the volume V of the solder as conditions, the relationship between the height of the molten solder and the load applied to the molten solder can be simulated for each combination. The present inventor confirmed that the simulation result and the experimental result of reflowing in a state where a low load (a load in a direction of pressing the bumped bare IC against the substrate) was applied from above the bumped bare IC were almost equal.

  Therefore, the desired load between the bumped bare IC and the substrate, the volume of the solder bumps, the number of solder bumps, and the land area is used as a parameter to determine the set load using the simulation results described above and applied to the bare IC with bumps. The height of the melted solder bumps can be controlled to the above-described desired height by controlling the lifting and lowering operation of the movable part by the VCM, that is, by controlling the force so that the load to be set becomes the set load.

  The solder model described above is for a case where the outer peripheral portion of the land of the substrate is covered with a resist, and a part of the land exposed from the resist is a solder bump mounting region. The solder model is appropriately assumed according to the state of the register based on the above-described simulation concept.

  In this embodiment, the case where the height of the melted solder bump is controlled using the result of the simulation will be described. However, a part or all of the calculation formulas used in the simulation may be used.

  Next, an example of a mounting method for mounting the bumped bare IC 17 on the substrate 18 using the mounting head described above will be described with reference to the flowchart shown in FIG. The control operation described below is executed by the control unit 3 provided in the component mounting apparatus. FIG. 4 shows an example of a control procedure by the control unit 3 when one bare IC 17 with bumps is flip-chip mounted on one substrate 18. In addition, when mounting the bare IC 17 with bumps on the substrate 18, an example of pressurizing the bare IC 17 with bumps from above (applying a load in a direction of pressing the bare IC 17 with bumps against the substrate 18, that is, applying a positive load). Show.

  First, in step S1, the control unit 3 obtains the volume of the solder bump 17a based on the height and radius of the solder bump 17a input from an input unit such as a keyboard (not shown), and calculates the obtained volume of the solder bump 17a. Store in a storage area (not shown). Further, the control unit 3 obtains a land area from the land radius of the substrate 18 input from an input unit such as a keyboard (not shown), and stores the obtained land area in a storage area (not shown). The control unit 3 stores the number of solder bumps 17a input from an input unit such as a keyboard (not shown) and the desired height between the bumped bare IC 17 and the substrate 18 in a storage area (not shown).

  Next, in step S2, the control unit 3 uses a simulation result stored in advance in a storage area (not shown) as a parameter using the volume of the solder bump 17a stored in the storage area in step S1 as a parameter. The value Fa is calculated, the calculated force command value Fa is stored in a storage area (not shown), and the VCM 30 is driven so that the detected value of the load cell 29 matches the force command value Fa. Thereby, the suction bit unit 10 comes into contact with the stopper of the moving body 1 with a load (set load) of the force command value Fa.

  Next, in step S3, the control unit 3 moves the mounting head to a position above the receiving position of the bumped bare IC 17 supplied from the component supply unit by an XY moving mechanism (not shown), and driving means (not shown). The mounting head (moving body 1) is moved up and down to attract and hold the bumped bare IC 17 to the tip of the nozzle 16, and then the XY moving mechanism moves the mounting head onto the substrate held by the mounting stage. Is moved above the mounting position.

  Next, in step S4, the controller 3 lowers the mounting head (moving body 1) by the driving means, and in step S5 detects that the mounting head (moving body 1) has been lowered by a predetermined amount. The lowering operation of the mounting head (moving body 1) is stopped. At this time, the mounting head (moving body 1) further descends and stops from a position where the solder bumps 17a of the bare IC 17 with bumps held by suction and the lands of the substrate 18 come into contact.

  As a result, the suction bit portion 10 moves away from the stopper, and the bumped bare IC 17 can be freely moved up and down. Further, the load applied to the bumped bare IC 17 can be detected by the load cell 29.

  When the mounting head is lowered, it is preferable to accelerate the lowering speed of the mounting head and decelerate the solder bump 17a and the land of the substrate 18 in contact with each other in order to increase the speed of component mounting.

  Next, in step S <b> 6, the control unit 3 increases the heating temperature of the heating head 13. The heating head 13 is energized at least before the solder bumps 17a of the bare IC 17 with bumps and the lands of the substrate 18 come into contact with each other, and preheated so that the solder bumps 17a have a predetermined temperature that does not melt. Is preferred.

  Next, in step S7, when the control unit 3 detects that the heating temperature has risen to a predetermined temperature at which the solder bump 17a can be melted, the control unit 3 proceeds to step S8 after a predetermined waiting time has elapsed, Is stopped and cooling blow is started in step S9. Cooling blow is performed by blowing cooling air from the blow nozzle 15 to the bare IC 17 with bumps. The cooling may be natural cooling regardless of the cooling air from the blow nozzle.

  Next, in step S10, when the control unit 3 detects that a predetermined time has elapsed since the start of the cooling blow, in step S11, the controller 16 releases the suction of the bumped bare IC 17 by the nozzle 16, and in step S12, The mounting head (moving body 1) is raised and the mounting of the bumped bare IC 17 on the substrate 18 is completed.

  Here, the predetermined time is set to a time from when the cooling blow is started until the solder bump 17a is completely solidified and the solder bump 17a and the land of the substrate 18 are reliably joined. Instead of detecting only the elapsed time since the start of cooling blow, the temperature of the nozzle 16, the bare IC 17 with bumps or the solder bumps 17a is monitored, and the temperature of the solder bumps 17a becomes below the freezing point. After a predetermined waiting time elapses from when this is detected, the process may move to the next step.

  As described above, in the present embodiment, in a state where the solder bumps 17a before the start of the cooling blow are melted, the control unit 3 sets the current based on the deviation between the detected value of the load cell 29 and the force command value Fa to the VCM 30. The load cell 29 is moved up and down via the rod 31 so that the detected value of the load cell 29 matches the force command value (set load) Fa. That is, the force control is executed so that the load applied to the bumped bare IC 17 is maintained at the load (set load) of the force command value Fa. Thus, by controlling the force on the melted solder bump 17a before the start of cooling blow, the height of the melted solder bump 17a can be controlled. Thermal expansion amount and solder bump solidification (solder bump) when the solder bumps of the mounting stage holding the movable part and the substrate holding the bare IC are melted (from the start of the temperature rise of the heating head to the completion of melting of the solder bumps) Even if there is a variation in the amount of shrinkage between the start of cooling and the completion of solidification of the solder bumps), the final height (gap) between the bumped bare IC 17 and the substrate 18 after the solidification of the solder bump 17a is obtained. It becomes possible to suppress the occurrence of variation, and the yield can be improved.

  In this embodiment, force control is executed from the start of the temperature rise of the heating head to the completion of solidification of the solder bump. However, it is sufficient that force control can be executed on the melted solder bump before the start of cooling blow. For example, during the period from the start of the temperature rise of the heating head to the completion of melting of the solder bump, position control is performed to raise the movable portion in accordance with the predicted thermal expansion amount of the movable portion and the mounting stage, and the solder bump You may switch to force control after the completion of melting. However, due to the influence of the ambient temperature, when the solder bump that has melted due to insufficient rise of the movable part is crushed and a bridge is generated, the temperature of the heating head starts from the start as in this embodiment. It is preferred to perform force control. Further, for example, position control for lowering the movable part in accordance with the shrinkage amount of the movable part and the mounting stage predicted in advance from the start of cooling blow (at the start of cooling of the solder bumps) may be executed. However, due to the influence of the ambient temperature and cooling air, when the moving part descends with respect to the contraction speed and a force to tear the solder bumps occurs, an open defect occurs, or conversely When the moving part descends faster than the speed, the force to crush the solder bumps works, and when cracks occur, force control is performed even when the solder bumps are cooled, as in this embodiment. Is preferably performed. In the present embodiment, when the position of the movable part is controlled, a mechanism for fixing and supporting the movable part is provided on the movable body 1, and the position of the movable part in the height direction is determined by the lifting and lowering operation of the movable body 1. Control. As a mechanism for fixing and supporting the movable part on the movable body 1, for example, a structure for generating a negative pressure in a gap between the inner surface of the rotating member 6 and the outer surface of the suction bit unit 10 may be provided. When the position of the movable portion is controlled from the start of the temperature rise of the heating head to the completion of melting of the solder bump, the height of the movable portion at the time when the solder bump 17a and the land of the substrate 18 come into contact with each other. Position control is performed with the position in the direction as the origin. Similarly, when the position of the movable portion is controlled from the start of the cooling of the solder bump 17a, the position control is performed with the position in the height direction of the movable portion at the time when the melting of the solder bump 17a is completed as the origin.

  Further, as in the present embodiment, if force control is executed during the melting of the solid-state solder bumps 17a by heating and during the cooling and solidification of the melted solder bumps 17a, There is no need to predict the amount of thermal expansion and contraction of the mounting stage.

  In addition, when the solder bumps 17a in the solid state are melted by heating, when the position control for raising the movable part according to the predicted thermal expansion amount of the movable part and the mounting stage is performed, the predicted solder bump is used. It is necessary to start raising the movable part at the melting start timing, but if the rise start timing is late with respect to the actual melting start timing, solder splatters, and if it is early, the solder bumps are pulled up in an unmelted state. Open failure occurs.

  On the other hand, if force control is performed while the solid-state solder bumps 17a are melted by heating as in the present embodiment, it is not necessary to predict the melting start timing of the solder bumps, and the predicted melting It is possible to avoid solder splattering and open defects due to a difference between the start timing and the actual melting start timing.

  In the present embodiment, since the balance mechanism is provided, even when the mounting head is lowered, even if acceleration / deceleration is performed, the force based on the weight compensated by the balance mechanism, for example, the movable part and the bumped bear IC When the total weight is compensated, the force based on the total weight (F = ma) is not applied to the load cell, so that the accuracy of force control is improved. Further, the acceleration when the mounting head is lowered can be increased, and the speed of component mounting can be increased.

  In this embodiment, the solder bumps 17a of the bare IC 17 with bumps and the lands of the substrate 18 are joined. However, solder is also supplied onto the lands of the substrate 18, and the substrate 18 side is connected. The same can be done when the solder and the solder bump 17a of the bare IC 17 with bump are joined.

  In the present embodiment, since the tension spring 39 is provided, it is necessary to always generate a force for canceling the tension load of the tension spring 39 in the VCM 30. In the case where the tension spring 39 is not provided, the force control may be turned on when the suction bit unit 10 is brought into contact with the stopper of the moving body 1 with the load of the force command value Fa (set load).

  In this embodiment, the solder bumps 17a of the bumped bare IC 17 and the lands of the substrate 18 are brought into contact with each other with a load (set load) of the force command value Fa. Are brought into contact with a load of a force command value different from 'Fa', and after contacting the solder bump 17a and the land of the substrate 18, the VCM 30 is adjusted so that the load detected by the load cell 29 becomes the force command value Fa. It may be driven. Further, the suction bit portion 10 may be brought into contact with the stopper of the moving body 1 with a load “0”.

  In the present embodiment, the mounting head (moving body 1) is lowered by a predetermined amount. However, the suction bit unit 10 is applied to the stopper of the moving body 1 with a load with a force command value larger than “Fa” (contact load). ), And the contact load is detected by the load cell 29 when the solder bump 17a and the land of the substrate 18 contact each other, thereby detecting the contact between the solder bump 17a and the land of the substrate 18 and detecting the contact. The mounting head may be further lowered by a predetermined pushing amount from the position at which it is done.

  In this embodiment, force control is executed when the solder bump 17a is cooled. For example, when cooling of the solder bump 17a is started, the force control is turned off or the load on the bumped bare IC 17 is set to “0”. Alternatively, the value may be set in the vicinity thereof, the suction of the bare IC 17 with bumps may be released, and the mounting head (moving body 1) may be raised. In this way, it is possible to avoid the occurrence of open failures and cracks due to the influence of the ambient temperature and cooling air.

  In the present embodiment, the case where the force control by the force command value Fa is executed after the solder bump 17a is melted until the cooling of the solder bump 17a is started has been described. For example, the solder bump 17a After melting, the force control by the force command value Fb different from the force command value Fa is started, and during the force control, the force command value is changed from Fb to Fa, and then the cooling of the solder bump 17a is started. May be.

  Further, in the present embodiment, when mounting the bumped bare IC 17 on the substrate 18, the bumped bare IC 17 is pressurized from above (a load (positive load) in a direction in which the bumped bare IC 17 is pressed against the substrate 18 is applied). However, after the solder bumps 17a are melted, a negative set load (a load in the direction in which the bare IC 17 with bumps is separated from the substrate 18 (negative load)) is applied to the bare ICs 17 with bumps. The attached bare IC 17 may be pulled upward to change the shape of the solder bump 17a into a vertically long shape. However, when force control is executed after the solder bump 17a is pulled upward, the negative set load is maintained. As described above, by forming the solder bumps 17a in a vertically long shape, even if the substrate 18 or the like is thermally deformed during use of the electronic device on which the substrate 18 on which the bumped bare IC 17 is mounted is used, the edge of the solder bump 17a. The stress concentration on can be relaxed.

  In the present embodiment, the case where the total weight of the movable portion and the bare IC 17 with bumps adsorbed to the movable portion is compensated by the balance mechanism has been described. However, a force larger than the force corresponding to the total weight is described. May be generated so that an upward force is applied to the movable portion. In this case, the force command value (set load) Fa calculated in step S2 may be corrected by adding the load applied to the pressure sensitive part of the load cell 29 by the balance mechanism.

  In this embodiment, the solder bump 17a in the solid phase is brought into contact with the land of the substrate 18 and then the solder bump 17a is melted. However, after the solder bump 17a is melted, the solder bump 17a is melted onto the land of the substrate 18. You may make it contact. In this case, the descending speed of the mounting head when the solder bumps 17a are in contact with the lands of the substrate 18 is made sufficiently low so that the solder does not scatter.

  As described above, by bringing the melted solder bumps 17 a into contact with the lands of the substrate 18, even if the solder bumps 17 a on the bare IC 17 with bumps vary in height (amount of solder), the solder bumps 17 a are attached to the substrate 18. When it comes into contact with the land, it spreads naturally. When the solid-state solder bumps 17a are brought into contact with the lands of the substrate 18, if the solder bumps 17a have a height variation, the solder bumps having a low height may be insufficiently wet. By bringing the bumps 17a into contact with the lands of the substrate 18, it is possible to avoid such a problem.

  Further, in this case, the suction bit portion 10 is brought into contact with the stopper of the moving body 1 with a load of a force command value Fb different from the force command value Fa, and the melted solder bump 17a contacts the land of the substrate 18. Sometimes, force control is performed using the force command value Fb, and during the force control, the force command value may be changed from Fb to Fa, and then the cooling of the solder bumps 17a may be started. If the load of the command value Fa (set load) is brought into contact with the stopper of the moving body 1, the height of the melted solder bump 17 a becomes a desired height when the solder bump 17 a contacts the land of the substrate 18. It becomes.

  In this case, since it is difficult to detect the contact load when the molten solder bump 17a contacts the land of the substrate 18, the mounting head (moving body 1) is lowered by a predetermined amount to melt the solder. The bumps 17 a are brought into contact with the lands of the substrate 18.

  Further, when a negative set load (a load in the direction of separating the bumped bare IC 17 from the substrate 18) is applied to the bumped bare IC 17 to change the shape of the solder bump 17a into a vertically long shape, the melted solder bump 17a. After the contact with the land of the substrate 18, force control may be executed with the force command value Fa.

Implementation device, final height between the mounting member and by controlling the solder height melted interposed between the mounted member, the mounting member after solidifying the solder and the mounted members of the present invention It is possible to suppress the occurrence of variation in (gap), improve the yield, and solidify the melted solder interposed between the mounting member and the mounted member to join the mounting member and the mounted member. It is useful for technology, and is useful for technology for flip-chip mounting of bare ICs with bumps, technology for manufacturing package-on-package ICs, and the like.

The figure which shows the outline | summary of a structure of the mounting head with which the component mounting apparatus in embodiment of this invention comprises. The figure which shows the outline | summary of a structure of the other example of the mounting head with which the component mounting apparatus in embodiment of this invention comprises. The figure which shows an example of the solder model used for the simulation in embodiment of this invention The flowchart figure which shows an example of operation | movement of the component mounting apparatus in embodiment of this invention The figure which shows the outline | summary of a structure of the mounting head which the conventional component mounting apparatus comprises.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile body 2 Mounting head base 3 Control part 4 Casing 5a Bearing 5b Bearing 6 Rotating member 6a Concave part 7, 9 Gear 8 Motor 10 Adsorption bit part 11a-11c Support shaft 12a-12d Hole 13 Heating head 14 Heat insulation part 15 Blow nozzle 16 Nozzle 17 Bumped bear IC
17a Solder bump 18 Substrate 19 Air supply chamber 20, 21 Air supply hole 21a Air holding chamber 22a, 22b Air seal 23 Holder portion 23a Recess 24 Bearing 25, 26 Air suction hole 27 Air seal 28 Compression spring 29 Load cell 30 Voice coil motor (VCM)
DESCRIPTION OF SYMBOLS 31 Rod 32 Magnet 33 Coil 34a, 34b Holding part 35 Oscillator 36 Balance weight 37 Support stand 38 Bearing 39 Tension spring 40 Holding member 41 Ball spline bearing 101 Pad 102 Land 103 Molten solder 103a Side face 201 Lifting drive part 202 Mounting head 203 Suction nozzle 204 Bare IC with bump
204a Solder bump 205 Substrate 206 Ceramic heater 207 Blow nozzle 208 Heat insulation part 209 Support shaft

Claims (1)

A movable part for holding the mounting member;
A drive unit that raises and lowers the lifting shaft and moves the movable portion on the same axis as the lifting shaft; and
On one side across the fulcrum, on the same axis as the elevating shaft of the drive unit, the movable unit that supports the elevating operation is supported by an air bearing, and on the other side, a weight is supported. A balance mechanism that is arranged facing the movable part and compensates for gravity so as to cancel at least the weight in the weight direction of the movable part;
A load that is disposed between the movable part and the drive part on the same axis as the lift axis of the drive part, and detects a load applied to the solder interposed between the mounting member and the mounted member. A detection unit;
A control unit that controls the lifting and lowering operation of the movable unit by the drive unit based on the load detected by the load detection unit;
The mounted member held by the movable part and the mounted member are in contact with each other via the molten solder, and the molten solder is cooled and solidified, thereby A mounting device for mounting the mounting member on a member,
Wherein in a state where said mounting member and the mounting member is contacted via solder the melted, as load detected by the load detection unit is goals load, lifting of the movable portion by the drive unit A mounting apparatus for controlling operation.

Images