JP5471500B2 - Electronic component joining apparatus and electronic component joining method - Google Patents

Description

  The present invention relates to an electronic component bonding apparatus and an electronic component bonding method, and relates to an electronic component bonding apparatus and an electronic component bonding method for mounting an electronic component on a substrate.

  When an electronic component such as a semiconductor chip is bonded to a substrate by an electronic component bonding apparatus, the electronic component to be bonded is held by a bonding head of the electronic component bonding apparatus, and the substrate is heated by a predetermined pressure while heating the held electronic component. Press to join. At this time, the electronic component and the substrate are joined by melting the solder balls disposed on the lower surface of the electronic component.

  The operation of the joining head in the process of joining the electronic component and the board by melting the solder ball is controlled based on the position until the solder ball placed on the lower surface of the electronic part comes into contact with the board. The load is controlled to be constant. A heater is embedded in the bonding head, and the electronic head is heated while pressing the electronic component against the substrate.

  When a certain amount of time has passed, the solder balls are sufficiently heated and melted. Even when the solder ball is melted, the bonding head is controlled so as to press the electronic component with a constant load. Therefore, the operation speed of the bonding head increases rapidly, and the solder ball is rapidly crushed. For this reason, there exists a possibility that an electronic component or a board | substrate may be destroyed. In addition, it is not known what the collapsed shape of the solder ball will be (ie, the collapsed shape cannot be controlled), so the collapsed shape has collapsed to other solder balls, wires, terminals, etc. near the solder ball. There is a risk that unintentional connection will occur due to the soldering, resulting in defects such as short circuits.

  In order to avoid this problem, for example, in the bonding apparatus disclosed in Patent Document 1, the pressing body portion (corresponding to the bonding head) holding the chip (corresponding to the electronic component) moves toward the substrate and is applied to the substrate. The chip is bonded to the substrate while keeping the pressure constant.

  The pressing body portion is controlled to move and press toward the substrate at a moving speed equal to or lower than a preset setting speed when the chip is bonded to the substrate. By controlling in this way, the chip and the substrate are not destroyed.

  However, in this method, since control is performed so as not to move at a speed higher than a preset speed, there is a possibility that it cannot be avoided from sufficient destruction of the chip and the substrate. In addition, since the rapid change in speed cannot be controlled, the solder ball cannot be sufficiently crushed.

  In order to avoid the above problem, for example, in the electronic component manufacturing apparatus disclosed in Patent Document 2, the mounting nozzle holding the electronic element moves toward the substrate, and the solder bump and the substrate arranged on the lower surface of the electronic element After the contact with the electrode, the electronic element is bonded to the substrate while controlling the pressing load to be a preset load. At this time, the solder bump is heated and melted during the control of the pressing load, and the electronic element is bonded to the substrate.

  Then, the mounting nozzle is rapidly lowered by the dissolution of the solder bump during the control of the pressing load. At this time, the mounting nozzle is controlled to stop the descent when it is lowered by a predetermined solder bump crushing distance. By controlling in this way, the electronic element will not suddenly collide with the substrate, and the electronic element and the substrate will not be destroyed.

  However, in this method, control is performed so that the descent is stopped when it is lowered by a predetermined solder bump crushing distance, so that the electronic element and the substrate are not destroyed by collision, but the crush-shaped control cannot be performed. .

JP 2007-141972 A JP 2003-179100 A

  Since the joining apparatus disclosed in Patent Document 1 described above only controls the pressing body portion not to move at a speed higher than a preset speed when joining the chip to the substrate, the chip and the substrate are sufficient. May be unavoidable from undue destruction. In addition, since a rapid change in the speed of the pressing body portion cannot be controlled, it is not possible to control the shape of the solder ball sufficiently crushed.

  Further, in the electronic component manufacturing apparatus disclosed in Patent Document 2 described above, when the electronic element is bonded to the substrate while controlling the pressing load, the mounting nozzle is rapidly lowered by the dissolution of the solder bump. At this time, the mounting nozzle is controlled to stop the descent when it is lowered by a predetermined solder bump crushing distance. For this reason, the electronic element and the substrate are prevented from being destroyed by collision, but the solder bumps cannot be crushed.

  The objective of this invention is providing the electronic component joining apparatus and electronic component joining method which solve the said subject.

  An electronic component bonding apparatus according to the present invention includes a bonding head that holds an electronic component and mounts the electronic component on a substrate, an actuator that moves the bonding head in a direction of approaching and separating from the substrate, and a movement by the actuator A position detector that detects the position of the bonding head, and a control unit that moves the bonding head by controlling the actuator based on a position signal of the bonding head from the position detector, The control unit starts load control for pressing the bonding head toward the substrate with respect to the actuator after the electronic component contacts the substrate when the electronic component is mounted on the substrate, and the speed of the bonding head is started. A load finger that is adjusted by a value corresponding to the speed of the joining head obtained from the position signal of the joining head in a direction to suppress the change. A value is output to the actuator, the actuator receives the load command value, presses the joining head toward the substrate based on the load command value, and the joining head is operated according to the operation of the actuator. The electronic component is pressed against the substrate and mounted via a bonding material provided in the electronic component.

  The electronic component bonding method of the present invention is an electronic component bonding method in which an electronic component is held on a substrate by holding the electronic component on a bonding head, and the electronic component contacts the substrate when the electronic component is mounted on the substrate. After that, load control for pressing the bonding head toward the substrate is started, and a load command value that is adjusted by a value corresponding to the speed of the bonding head in a direction to suppress a change in the speed of the bonding head is created. The bonding head is pressed in the direction of the substrate based on the value, and the bonding head presses the electronic component against the substrate and is mounted via a bonding material provided in the electronic component.

  According to the present invention, when an electronic component is mounted on a substrate, load control for pressing the bonding head toward the substrate is started after the electronic component contacts the substrate. Then, create a load command value that is adjusted according to the speed of the bonding head in a direction to suppress the speed change of the bonding head, press the bonding head toward the board based on this load command value, and press the electronic component against the board It is mounted via a bonding material.

  For this reason, after the load control is started, the electronic component is pressed against and mounted on the substrate while suppressing a change in the speed of the bonding head, so that the electronic component does not move rapidly toward the substrate. For this reason, an electronic component does not collide with a board | substrate and destruction of an electronic component and a board | substrate can be avoided. In addition, since the electronic component is mounted on the substrate in a state where the electronic component does not move suddenly toward the substrate, the collapsed shape of the bonding material is similar to the shape of the original bonding material.

It is a figure which shows 1st Embodiment of the electronic component joining apparatus of this invention. It is a figure which shows 2nd Embodiment of the electronic component joining apparatus of this invention. It is a flowchart which shows an example of the operation | movement of the 2nd Embodiment of this invention. It is a figure which shows an example of the load control by the control part of the electronic component joining apparatus of this invention. It is a figure which shows an example of the relationship between the control system of the electronic component joining apparatus of this invention, and the position of a joining head. It is a figure which shows an example of the collapsed shape of a solder ball.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a first embodiment of an electronic component bonding apparatus according to the present invention.

  In this embodiment, the joining head 1, the actuator 2, the position detector 3, and the control unit 4 are configured.

  The bonding head 1 has a suction function at the bottom. Then, the electronic component 6 such as a semiconductor chip having the bonding material 7 on the lower surface is sucked and held, the electronic component 6 is pressed against the substrate 5, and is mounted on the substrate 5 through the bonding material 7.

The actuator 2 is, for example, a linear motor having a servo function that moves the bonding head 1 in the direction in which the bonding head 1 approaches and separates from the substrate 5 (vertical direction).

  The position detector 3 detects the vertical position of the bonding head 1 that is moved by the actuator 2. That is, the position detector 3 is, for example, a linear encoder, and detects the position of the bonding head 1 that moves according to the operation of the actuator 2.

  The control unit 4 controls the actuator 2 based on the position signal of the bonding head 1 from the position detector 3 to move the bonding head 1.

  When the electronic component 6 is mounted on the substrate 5, the control unit 4 starts load control for pressing the bonding head 1 toward the substrate 5 with respect to the actuator 2 after the electronic component 6 contacts the substrate 5. At this time, since the electronic component 6 is pressed against the substrate 5, the bonding material 7 may be crushed and the bonding head 1 may approach the substrate 5 rapidly. In order to avoid this, the speed of the bonding head 1 is obtained from the position signal of the bonding head 1 detected by the position detector 3, and the value according to the speed of the bonding head 1 is set in a direction to suppress the speed change of the bonding head 1. The adjusted load command value is output to the actuator 2.

  The actuator 2 receives this load command value and presses the bonding head 1 toward the substrate 5 based on this load command value. The bonding head 1 presses the electronic component 6 against the substrate 5 in accordance with the operation of the actuator 2 and mounts it via the bonding material 7.

  Thus, when the electronic component 6 is mounted on the substrate 5, the electronic component bonding apparatus according to the present embodiment starts load control for pressing the bonding head 1 toward the substrate 5 after the electronic component 6 contacts the substrate 5. To do. Then, a load command value that is adjusted by a value corresponding to the speed of the bonding head 1 in a direction to suppress the speed change of the bonding head 1 is created, and the bonding head 1 is pressed in the direction of the substrate 5 based on the load command value. 6 is pressed against the substrate 5 and mounted via a bonding material 7.

  For this reason, after the load control is started, the bonding head 1, that is, the electronic component 6 is pressed against the substrate 5 and mounted while suppressing the speed change of the bonding head 1, so that the electronic component 6 moves rapidly toward the substrate 5. There is nothing to do. For this reason, the electronic component 6 does not collide with the board | substrate 5, and destruction of the electronic component 6 and the board | substrate 5 can be avoided. Further, since the electronic component 6 is mounted on the substrate 5 in a state where the electronic component 6 does not move suddenly in the direction of the substrate 5, the collapsed shape of the bonding material 7 is similar to the shape of the original bonding material 7.

  FIG. 2 is a diagram showing a second embodiment of the electronic component bonding apparatus according to the present invention.

  In this embodiment, the joining head 1, the mounting stage 10, the actuator 2, the position detector 3, and the control unit 4 are configured.

  The bonding head 1 has a suction function at the bottom and includes a heater unit 11. Then, an electronic component 6 (hereinafter, referred to as a chip 8) such as a semiconductor chip having a bonding material 7 (for example, solder balls, gold bumps, conductive paste, etc., which will be described below as solder balls 9) on the lower surface is adsorbed. The solder ball 9 is heated and melted via the chip 8 by the heater unit 11, and the chip 8 is pressed against the substrate 5 and mounted on the substrate 5.

  The mounting stage 10 holds the substrate 5 on which the chip 8 is mounted by vacuum suction or the like.

  The actuator 2 is, for example, a linear motor having a servo function that moves the bonding head 1 in a direction (vertical direction) to approach and separate the mounting stage 10.

  The position detector 3 detects the vertical position of the bonding head 1 that is moved by the actuator 2. That is, the position detector 3 is, for example, a linear encoder, and detects the position of the bonding head 1 that moves according to the operation of the actuator 2. Specifically, the position detector 3 detects the distance from the mounting stage 10 to the suction surface of the chip 8 of the bonding head 1, for example.

  The control unit 4 controls the actuator 2 based on the position signal of the bonding head 1 from the position detector 3 to move the bonding head 1.

  Next, the operation of the electronic component bonding apparatus according to the present embodiment will be described in detail with reference to FIGS. 3, 4, 5, and 6. FIG.

  FIG. 3 is a flowchart showing an example of the operation of the embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of load control by the control unit 4 of the electronic component bonding apparatus according to the present invention.
The control unit 4 differentiates the position signal (z [mm]) of the position detector 3 indicating the position of the bonding head 1 with time (dz / dt [mm / t]), and gain (C [Nt / mm] ]) To create a feedback value (C * dz / dt (unit is force, eg, N (Newton))) (damping term). Then, the control unit 4 subtracts a feedback value (damping term) from a predetermined load setting value (Fs: unit is force, for example, N (Newton)) to obtain a load command value (Fd: unit is force, for example, N (Newton). )) Is output to the actuator 2. Based on this load command value, the actuator 2 presses the bonding head 1 toward the substrate 5 so that the load applied to the bonding head 1 becomes this load command value. That is, the control unit 4 outputs a load command value obtained by subtracting the damping term from the load setting value to the actuator 2, thereby controlling the load on the joining head 1 in a direction in which the speed change is suppressed.

  Here, the load setting value (Fs) is a value serving as a reference for the force for pressing the chip 8 against the substrate 5 and is appropriately determined by an experiment or the like. The load command value (Fd) is a command value of a force for actually pressing the chip 8 against the substrate 5. The gain (C) is used to change the unit of the differential value of the position signal (z) from [mm / t] to [N] and determine the magnitude of the damping term, and is determined as appropriate through experiments or the like.

  FIG. 5 is a diagram illustrating an example of the relationship between the control method of the electronic component bonding apparatus according to the present invention and the position of the bonding head 1.

  The vertical axis (position) indicates, for example, the distance from the mounting stage 10 to the suction surface of the chip 8 of the bonding head 1. The controller 4 designates the position and speed of the actuator 2 to control the position of the bonding head 1, and causes the bonding head 1 to approach the substrate 5 at a constant speed until touch detection. Touch detection refers to detecting that the tip of the solder ball 9 of the bonding head 1 is in contact with an electrode on the substrate 5. In the touch detection, for example, the position signal of the bonding head 1 from the position detector 3 is time-differentiated to obtain the speed of the bonding head 1 and is detected when the change in the speed exceeds a predetermined range.

  When the touch is detected, the control unit 4 switches the control of the bonding head 1 by the actuator 2 from position control to load control for pressing in the direction of the substrate 5. Further, the heater unit 11 is controlled to heat the solder ball 9 via the chip 8. When the solder ball 9 is melted, the joining head 1 is pressed toward the substrate 5, so that the support by the solder ball 9 suddenly weakens and sinks rapidly toward the substrate 5. At this time, the control unit 4 subtracts the damping term from the load setting value and outputs the load command value to the actuator 2 as shown in FIG. As a result, sudden subsidence is suppressed (orbit in the present embodiment). On the other hand, when the load command value is output to the actuator 2 without subtracting the damping term from the load setting value, the joining head 1 sinks suddenly, the chip 8 collides with the substrate 5, or the collapsed shape of the solder ball 9 May be disturbed (orbit when there is no damping term).

FIG. 6 is a diagram illustrating an example of a collapsed shape of the solder ball 9 after the chip 8 is mounted on the substrate 5.
(A) is a figure which shows an example of the collapsed shape of the solder ball 9 after mounting the chip | tip 8 on the board | substrate 5 by control in case there is no damping term. An example of the collapsed shape of the solder ball 9 when the control unit 4 outputs the load command value to the actuator 2 without subtracting the damping term from the load setting value is shown. The size of the solder ball 9 after being crushed is considerably larger than the size of the original solder ball 9, and the shape of the solder ball 9 after being crushed is irregularly changed from a circle.
(B) is a figure which shows an example of the collapsing shape of the solder ball 9 after mounting the chip | tip 8 in the board | substrate 5 in this Embodiment. An example of the collapsed shape of the solder ball 9 when the control unit 4 subtracts the damping term from the load setting value and outputs the load command value to the actuator 2 is shown.
The size of the solder ball 9 after being crushed is slightly larger than the size of the original solder ball 9. Moreover, the shape of the solder ball 9 after being crushed is also nearly circular.

  Here, with reference to FIG. 3, the operation of pressing and mounting the chip 8 held by the bonding head 1 on the substrate 5 will be described.

  First, in step S <b> 1 of FIG. 3, the mounting stage 10 holds the substrate 5 on which the chip 8 is mounted by vacuum suction or the like under the control of the control unit 4. The chip 8 is held by vacuum suction or the like at a predetermined initial position.

  In step S <b> 2 of FIG. 3, under the control of the control unit 4, the substrate 5 held on the mounting stage 10 and the chip 8 mounted on the substrate 5 are set on the respective planes facing each other with a certain distance apart. . And it aligns in the horizontal direction so that the solder ball 9 of the chip 8 faces a predetermined position (for example, the position of the electrode) on the substrate 5. That is, when the bonding head 1 is lowered, the solder ball 9 of the chip 8 is aligned with the position of the electrode on the substrate 5.

  In step S <b> 3 of FIG. 3, the control unit 4 designates the position and speed of the actuator 2, moves the joining head 1 vertically toward the substrate 5 by the actuator 2, and moves the solder balls 9 of the chip 8 to the substrate 5. Contact the electrode. That is, as shown in FIG. 5, the control unit 4 controls the position of the actuator 2 so that the bonding head 1 approaches the substrate 5 at a constant speed, and performs touch detection.

  In step S <b> 4 of FIG. 3, after detecting the touch, the control unit 4 controls the heater unit 11 to heat the solder ball 9 via the chip 8 as shown in FIG. 5. Further, the control unit 4 switches to load control for pressing the bonding head 1 toward the substrate 5 with respect to the actuator 2.

  Then, as shown in FIG. 4, the control unit 4 differentiates (dz / dt) the position signal (z) of the position detector 3 indicating the position of the bonding head 1 received from the position detector 3 with respect to time. A feedback value (C * dz / dt), that is, a damping term is created by multiplying the gain (C). Then, the feedback value (damping term) is subtracted from the predetermined load setting value (Fs), and the load command value (Fd) is output to the actuator 2. Based on the load command value, the actuator 2 controls the load applied to the joining head 1 to be the load command value. As described above, the control unit 4 subtracts the damping term from the predetermined load setting value [N] to obtain the load command value. Therefore, when the speed of the bonding head 1 increases, the load command value decreases. In addition, when the speed decreases, the actuator 2 controls the load so that the load command value increases. That is, the load is controlled in a direction that suppresses the speed change. The solder ball 9 is heated by the heater unit 11 while being pressed against the substrate 5 by this load control. Then, as shown in FIG. 5, when a certain time elapses due to this heating, the solder ball 9 changes from a solid to a liquid and melts. When the solder ball 9 melts, the joining head 1 suddenly sinks in the direction of the substrate 5 because the support by the solder ball 9 suddenly weakens. At this time, since the load is controlled by the control unit 4 in a direction to suppress the speed change, the rapid subduction of the bonding head 1 is suppressed. As a result of such control by the control unit 4, the solder ball 9 is mounted on the substrate 5 with the size and shape as shown in FIG. 6B.

  In step S5 of FIG. 3, the control unit 4 releases the vacuum suction of the bonding head 1 and releases the chip 8 after a time determined to be sufficiently connected, and the bonding head 1 is brought to the initial position by the actuator 2. Transition.

  As described above, according to the present embodiment, when the chip 8 is mounted on the substrate 5, load control for pressing the bonding head 1 toward the substrate 5 is started after the chip contacts the substrate 5. Then, a load command value that is adjusted by a value corresponding to the speed of the bonding head 1 in a direction to suppress the speed change of the bonding head 1 is created, and the bonding head 1 is pressed toward the substrate 5 based on the load command value, and the solder ball 9 is melted and the chip 8 is pressed against the substrate 5 and mounted. For this reason, after the load control is started, the bonding head 1 is pressed toward the substrate 5 while suppressing the speed change of the bonding head 1, the solder ball 9 is melted, and the chip 8 is pressed against the substrate 5 for mounting. 8 does not move rapidly toward the substrate 5. For this reason, chip 8 does not collide with substrate 5, and destruction of chip 8 and substrate 5 can be avoided. Further, since the chip 8 is mounted on the substrate 5 without the chip 8 moving rapidly toward the substrate 5, the collapsed shape of the solder ball 9 is similar to the original shape of the solder ball 9. As a result, the quality of the substrate 5 on which the chip 8 is mounted is improved, and the defective product occurrence rate is reduced.

1 Joining head 1
DESCRIPTION OF SYMBOLS 2 Actuator 3 Position detector 4 Control part 5 Board | substrate 6 Electronic component 7 Joining material 8 Chip 9 Solder ball 10 Mounting stage 11 Heater part

Claims (10)

A joining head for holding an electronic component and mounting the electronic component on a substrate;
An actuator for moving the bonding head in a direction to approach and separate from the substrate;
A position detector for detecting the position of the joining head moved by the actuator;
A controller that controls the actuator based on a position signal of the bonding head from the position detector to move the bonding head;
The control unit starts load control for pressing the bonding head toward the substrate with respect to the actuator after the electronic component contacts the substrate when the electronic component is mounted on the substrate. A load command value that is increased or decreased by a value corresponding to the speed of the bonding head obtained from the position signal of the bonding head in a direction to suppress a speed change is output to the actuator.
The actuator receives the load command value, and presses the joining head toward the substrate based on the load command value.
The bonding head is mounted via a bonding material provided to the electronic component by pressing the electronic component against the substrate according to the operation of the actuator.
An electronic component joining apparatus characterized by the above. The control unit obtains a speed of the joining head from the position signal of the joining head from the position detector, and a damping value proportional to the speed serves as a reference value for pressing the joining head toward the substrate. Subtracting from a predetermined load setting value indicating the load command value,
The electronic component joining apparatus according to claim 1, wherein:   The controller controls the position of the actuator to move the bonding head in the direction of the substrate at a constant speed to bring the electronic component into contact with the substrate. After the contact, the control unit moves the bonding head toward the substrate in the direction of the substrate. 3. The electronic component bonding apparatus according to claim 1, wherein the load control is switched to the load control that is pressed against the electronic component.   4. The electronic component bonding apparatus according to claim 3, wherein the contact of the electronic component with the substrate is detected based on a change in speed of the bonding head. A mounting stage for holding the substrate for mounting the electronic component;
The electronic component has the bonding material on a lower surface, and the bonding head presses the bonding material onto an electrode of the substrate held on the mounting stage. 3. The electronic component joining apparatus according to 3, or 4. In an electronic component bonding method for holding an electronic component on a bonding head and mounting the electronic component on a substrate,
When mounting the electronic component on the substrate, after the electronic component contacts the substrate, start load control to press the bonding head toward the substrate,
Create a load command value that is adjusted by a value corresponding to the speed of the bonding head in a direction to suppress the speed change of the bonding head,
Based on the load command value, the bonding head is pressed toward the substrate,
The bonding head presses the electronic component against the substrate and is mounted via the bonding material included in the electronic component.
An electronic component joining method characterized by the above. The speed of the bonding head is obtained, and a damping term proportional to the speed is subtracted from a predetermined load setting value indicating a load value serving as a reference for pressing the bonding head in the substrate direction to obtain the load command value.
The electronic component joining method according to claim 6.   The bonding head is moved in the substrate direction at a constant speed by position control, the electronic component is brought into contact with the substrate, and after the contact, the bonding head is switched from the position control to the load control for pressing in the substrate direction. 8. The electronic component joining method according to claim 6, wherein the electronic component is joined.   9. The electronic component bonding method according to claim 8, wherein the contact of the electronic component with the substrate is detected based on a change in speed of the bonding head.   The electronic component has the bonding material on a lower surface, and the bonding head presses the bonding material onto an electrode of the substrate held on a mounting stage. The electronic component joining method according to 8 or 9.

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