JP4315284B2 - Ultrasonic bonding head and ultrasonic bonding method - Google Patents

Description

  The present invention relates to an ultrasonic bonding head and an ultrasonic bonding method, and more particularly to an ultrasonic bonding head and an ultrasonic bonding method for applying ultrasonic vibration energy and thermal energy to an object to be bonded.

  In the ultrasonic bonding method, it has been conventionally known to ensure an efficient and highly reliable bonding state by applying both ultrasonic vibration energy and thermal energy to a bonding object. As an ultrasonic bonding head for realizing such an ultrasonic bonding method, an ultrasonic transducer 21 is coupled to one end of a resonator 22 as shown in FIG. An action part 23 that abuts the object to be joined is provided at the part, a support part 24 that supports the resonator 22 is provided at a pair of nodes of the vibration mode, and a heater 25 that heats the resonator 22 at the part of the node. Is known (for example, see Patent Document 1).

In addition, as shown in FIG. 6, a heating body 33 incorporating a heater 34 is disposed in a non-contact state on both sides of the resonator 31 in the vicinity of the action portion 32, and the action portion 32 is heated by radiant heat from the heater 33. Something that is supposed to do is also considered.
JP-A-9-122934

  However, in the configuration of the ultrasonic bonding head shown in FIG. 5, the resonator 22 is directly heated by the heater 25. However, since the heater 25 is heated at the node position of the resonator 22, The distance to 23 is long, so that the thermal efficiency is poor, and conversely the distance to the ultrasonic transducer 21 is short, and the ultrasonic transducer 21 is likely to be exposed to high temperatures, which may adversely affect the vibration system. There is.

  In order to solve such a problem, it is conceivable to arrange the heater 25 in the vicinity of the action portion 23. However, since the vicinity of the action portion 23 is subjected to ultrasonic vibration, the heater 25 and its wiring are extremely There is a problem of damage in a short time, which is not feasible. Therefore, although an ultrasonic bonding head having the configuration shown in FIG. 6 is considered, since it is indirect heating by radiant heat from the heating body 33, the thermal efficiency is poor and the temperature of the action portion 32 is accurately controlled. In addition, there is a problem that it is difficult to stably obtain a highly reliable bonding state.

  In view of the above-described conventional problems, the present invention provides an ultrasonic bonding head and an ultrasonic bonding method capable of effectively applying thermal energy without adversely affecting the vibration system, and capable of bonding efficiently and with high reliability. The purpose is to do.

  An ultrasonic bonding head according to the present invention includes an ultrasonic vibration generating means, a resonator having an action portion coupled to the ultrasonic vibration generating means and imparting ultrasonic vibration energy to an object to be joined, and an action portion of the resonator. Or the heating body arrange | positioned so that contact / separation movement is possible with respect to the vicinity, and the drive means which moves a heating body between the position which contacted the resonance body, and the separated position are provided. Here, the vicinity of the action part is preferably a position as close as possible to the action part, and may be a position at least between the action part and the node of the resonator closest to the action part.

  According to this configuration, before the joining operation of the objects to be joined, the heating body is brought into contact with the action part of the resonator or the vicinity thereof by the driving means, so that the vibration system is not adversely affected and efficient by direct heat transfer. After the heating body is moved away from the resonator immediately before joining to eliminate the possibility of damaging the heating body, the ultrasonic vibration generating means is operated to input the ultrasonic vibration to the resonator. Thus, ultrasonic vibration energy and thermal energy can be applied to the objects to be bonded, and bonding can be performed efficiently and with high reliability.

  In addition, if the temperature detecting means is disposed so as to be able to contact and separate from the working surface of the resonator or the vicinity thereof together with the heating member, the heating temperature of the resonator can be controlled appropriately, and a highly reliable bonding state can be achieved. It can be obtained stably.

  Further, the ultrasonic bonding method of the present invention is an ultrasonic bonding method in which ultrasonic vibration energy and thermal energy are applied to an object to be bonded from an action part of a resonator coupled to ultrasonic vibration generating means. A step of heating a heating body in contact with or near the action part of the resonator, a step of pressing the object to be joined via the action part of the resonator, and a step of separating the heating body from the resonator in a pressurized state. And a step of inputting ultrasonic vibrations from the ultrasonic vibration generating means to the resonator and joining them in a state in which they are made.

  According to this configuration, the heating body is brought into contact with or in the vicinity of the action portion of the resonator so that the vibration system is not adversely affected and is efficiently heated by direct heat transfer. The heating object by applying ultrasonic vibration to the resonator in a state where the heating object is separated from the resonator so that the heating object is not damaged by receiving the ultrasonic vibration. The ultrasonic vibration energy and the thermal energy can be applied to the object to be bonded without fear of damaging the substrate, and the bonding can be performed efficiently and with high reliability.

  According to the ultrasonic bonding head and the ultrasonic bonding method of the present invention, the resonator can be efficiently heated by direct heat transfer from the heating body, and then the heating body is separated from the resonator to the resonator. By inputting the ultrasonic vibration, it is possible to apply the thermal energy together with the ultrasonic vibration energy to the object to be bonded with high thermal efficiency without causing the damage to the heating body and to perform the bonding efficiently and with high reliability.

  Hereinafter, an ultrasonic bonding head according to an embodiment of the present invention and an ultrasonic bonding method using the same will be described with reference to FIGS.

  1 and 2, reference numeral 1 denotes an ultrasonic bonding head, which is configured by disposing a resonator 3 at a lower end portion of a head frame 2. The resonator 3 is mounted by fixing to the head frame 2 mounting protrusions 3a that protrude from both sides of the node position of the resonance mode. The lower end portion of the resonator 3 projects downward from the lower end surface of the head frame 2, and the electronic component 14 (see FIG. 3) as an object to be bonded is held on the lower end surface of the resonator body 3 so as to generate ultrasonic vibration energy. And an ultrasonic vibrator 5 (see FIG. 3) as an ultrasonic vibration generating means at an appropriate position of the resonator 3 so that the action portion 4 is ultrasonically vibrated substantially parallel to the surface thereof. ) Are combined.

  At the lower end of the head frame 2, the heating body 6 incorporating the heater 7 is disposed so as to be opposed to both sides of the lower end portion of the resonator 3 so as to be movable between a position contacting the resonator 3 and a position spaced apart from the position. ing. Further, the middle portion of the swing arm 9 is pivotally supported by pivot brackets 8 projecting on both lower sides of the head frame 2, and the lower end portion 9 a of the swing arm 9 is the resonance body 3 of the heating body 6. A telescopic actuator 10 such as a cylinder device is interposed between the upper end portion 9b of the swing arm 9 and the head frame 2 as a driving means, which is coupled to a coupling portion 6a provided at the opposite end. Thus, by the expansion / contraction operation of the expansion / contraction actuator 10, the heating body 6 is moved between the position where it contacts the resonator 3 and the position where it is separated.

  As the resonator 3, the heat capacity between the contact portion of the heating body 6 and the action portion 4 is large and the thermal conductivity is high, while the portion on the opposite side of the contact portion of the heating body 6 from the action portion 4 is What was comprised so that heat conductivity might become low is suitable.

  A temperature detecting means 11 such as a thermocouple is extended from one heating body 6 toward the action portion 4 of the resonator 3, and the tip of the temperature detecting means 11 is in a state where the heating body 6 is in contact with the resonator 3. Is configured to be fitted into and contacted with a measurement hole provided in the action portion 4 to measure the temperature. When the heating body 6 is separated from the resonator 3, the temperature detection means 11 is also separated from the action portion 4. Further, a pressurizing unit 12 (see FIG. 3) presses the head frame 2 downward and pressurizes the electronic component 14 (see FIG. 3) via the action part 4 of the resonator 3. ) Is arranged.

  Next, an operation of ultrasonically bonding the bumps of the electronic component 14 as an object to be bonded to the electrodes of the circuit board 13 by the ultrasonic bonding head 1 having the above configuration will be described with reference to FIGS.

  First, as shown in FIG. 3A, prior to ultrasonic bonding, the electronic component 14 is sucked and held by the action part 4 of the resonator 3, and the telescopic actuator 10 is extended as shown in FIG. Then, the heating element 6 is brought into contact with the vicinity of the action part 4 to heat the action part 4 of the resonator 3. At this time, the temperature of the action part 4 is detected by the temperature detection means 11, and the temperature of the action part 4 is accurately controlled so that the action part 4 reaches a predetermined temperature by performing energization control on the heater 7 of the heating body 6 according to the detected temperature. Is done. In FIG. 4, only heating is ON and pressurization and ultrasonic waves are OFF.

  Next, as shown in FIG. 3B, the pressurizing means 12 is operated, the head frame 2 is lowered, and the electronic component 14 is brought into contact with the circuit board 13 via the action part 4 of the resonator 3. The pressurizing force is increased, and when the predetermined pressurizing force is reached, the pressurizing force is maintained. At the time of entering the pressurizing step, as shown by a solid line in FIG. 4, the heating body 6 may be separated to turn off the heating, but as shown in FIG. 3B and as shown by a broken line in FIG. In addition, heating ON may be continued by bringing the heating element 6 into contact with the resonator 3 until the applied pressure reaches a predetermined value.

  Next, as shown in FIG. 3 (c), the heating body 6 is separated from the resonator 3 by contracting the telescopic actuator 10 as shown in FIG. By operating the vibrator 5, ultrasonic vibration is input to the resonator 3 to resonate, and ultrasonic vibration energy is applied to the electronic component 14 via the action unit 4. Further, heat energy is also given simultaneously by heat transfer from the heated resonator 3. Thus, the bumps of the electronic component 14 and the electrodes of the circuit board 13 are bonded efficiently and with high reliability by applying ultrasonic vibration energy and thermal energy to their bonding surfaces. In FIG. 4, heating is OFF and pressurization and ultrasonic waves are ON.

  By the way, the pressurizing step for applying the ultrasonic vibration is usually about 0.1 to 0.5 sec. Therefore, the temperature drop of the resonator 3 due to the heat radiation during that time is so small that it can be ignored, and the heated resonator 3 is heated. The heat energy from can be sufficiently applied.

  In addition, as shown with a broken line in FIG. 4, it is not made to maintain a fixed pressurization force in a pressurization process, but it is made to increase a pressurization force gradually from the initial stage of a pressurization process to the completion time of a joining process. Anyway.

  When the joining is completed, the operation of the ultrasonic vibrator 5 is stopped and the pressurizing means 12 is restored, the pressurization and the ultrasonic wave are turned off, the heating body 6 is brought into contact with the resonator 3 and the heating is turned on. It becomes.

  According to the present embodiment, the heating body 6 is brought into contact with the vicinity of the action portion 4 of the resonator 3 as described above, so that it can be efficiently heated by direct heat transfer without adversely affecting the vibration system. In this state, the electronic component 14 is pressurized via the action part 4 of the resonator 3, and the ultrasonic vibrator 5 is operated in a state where the heating body 6 is separated from the resonator 3, and the resonator 3 is ultrasonicated. By applying vibration, there is no fear of damaging the heating element 6 by ultrasonic vibration, and heat transfer is performed directly and efficiently, so that ultrasonic vibration energy and heat energy are applied to the electronic component 14 efficiently and with high reliability. It can be joined to the circuit board 13 with good performance.

  In the description of the above embodiment, the example in which the heating body 6 is brought into contact with the vicinity of the action portion 4 of the resonator 3 is shown, but the heating portion 6 may be brought into direct contact with the action portion 4.

  In the ultrasonic bonding head and the ultrasonic bonding method of the present invention, the heating body can be efficiently heated by direct heat transfer by bringing the heating body into contact with the resonator, and then the resonance is performed while the heating body is separated from the resonator. By inputting ultrasonic vibration to the body, bonding with ultrasonic vibration energy and thermal energy can be performed efficiently without fear of damaging the heating body, such as when bonding bumps of electronic components to electrodes on the substrate, etc. This is useful for ultrasonic bonding of mounting objects with a small heat capacity.

It is a front view of the principal part of the ultrasonic bonding head of the heating state in one embodiment of the present invention. It is a front view of the principal part of the ultrasonic joining head of the heating body separation state in the embodiment. It is explanatory drawing of the ultrasonic joining process in the embodiment. It is a timing diagram of the ultrasonic bonding process in the same embodiment. It is a schematic block diagram of the ultrasonic bonding head of a prior art example. It is a schematic block diagram of the ultrasonic joining head of another prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic bonding head 3 Resonator 4 Action part 5 Ultrasonic transducer (ultrasonic vibration generating means)
6 Heating body 10 Telescopic actuator (drive means)
DESCRIPTION OF SYMBOLS 11 Temperature detection means 12 Pressurization means 14 Electronic component (joining object)

Claims (3)

  Resonance body having ultrasonic vibration generating means, an action portion coupled to ultrasonic vibration generation means and applying ultrasonic vibration energy to the object to be joined, and contact or separation with respect to or near the action portion of the resonance body An ultrasonic bonding head comprising: a heating body movably disposed; and a driving unit that moves the heating body between a position in contact with the resonator and a position separated from the resonance body.   2. The ultrasonic bonding head according to claim 1, wherein temperature detecting means is disposed so as to be able to contact and separate from the working surface of the resonator or the vicinity thereof together with the heating body. An ultrasonic joining method in which ultrasonic vibration energy and thermal energy are applied to an object to be joined from an action part of a resonator coupled to an ultrasonic vibration generating means, and heating is performed on or near the action part of the resonator. Resonating from the ultrasonic vibration generating means in a state where the body is contacted and heated, a step where the object to be joined is pressurized via the action part of the resonator, and a state where the heating body is separated from the resonator And a step of joining the body by inputting ultrasonic vibration.

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