JP2009028728A - Ultrasonic vibration bonding method, device formed by the same, and ultrasonic vibration bonding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic vibration bonding method in which the workpieces can be stably and surely bonded with each other without breakage thereof in an ultrasonic vibration bonding apparatus for bonding a plurality of overlapped workpieces with each other by the ultrasonic vibration energy, and to provide the ultrasonic vibration bonding apparatus. <P>SOLUTION: The ultrasonic vibration energy is detected by an ultrasonic vibration energy control unit 31a. Before the ultrasonic vibration energy is rapidly reduced from the bonding start, the pressure applied to a workpiece is increased by a pressurization control unit 31c, and the voltage and the current applied to an oscillator 8 by the ultrasonic vibration energy control unit 31a are controlled by a resonance amplitude control unit 31b so that the amplitude of a resonator 7 is constantly maintained at the preset value. After the ultrasonic vibration energy is rapidly reduced, the amplitude of the resonator 7 is controlled to be damped to prevent damages to the workpiece. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic vibration bonding method and an ultrasonic vibration bonding apparatus for bonding a plurality of superposed objects by ultrasonic vibration.

  Conventionally, as a method of joining a plurality of objects to be joined, by applying predetermined ultrasonic vibration energy for a predetermined time while simultaneously pressurizing the objects to be joined together, There is a method called ultrasonic vibration bonding for bonding.

  In this method, ultrasonic vibration is applied to the object to be bonded, and "slip" is generated on the surface of the object to be rubbed to remove the oxide film and impurities on the surface of the object to be bonded, and the new surface is exposed to be exposed. This is a method of joining joined objects.

  As such a method, conventionally, by performing control to increase the pressure applied to the object to be bonded, sufficient “slip” necessary for bonding is generated between the objects to be bonded. A method of joining has been proposed.

  In this case, the ultrasonic vibration is sequentially transmitted to the first object to be bonded held by the resonator, the second object to be bonded held by the stage, and the stage. However, when the applied pressure is increased in this way, when the applied pressure is large from the beginning, the frictional force at each transmission interface from the resonator to the stage is large, so the first and second workpieces are joined. Since “slip” does not occur at the joint and a new surface does not appear on the surface of the joint, there is a possibility that both objects to be joined cannot be joined. In addition, when the applied pressure is small, the frictional force between the resonator and the first workpiece is small, so that “slip” occurs between the resonator and the first workpiece, and the ultrasonic vibration is the first. And it is not transmitted to a 2nd to-be-joined object, and a "slip" will not arise between to-be-joined objects.

  On the other hand, when the bonding area between the bonded portions of the first and second objects to be bonded increases in the bonding process, the bonding force between the objects to be bonded increases, and the bonding force between the objects to be bonded decreases between the resonator and the first object. Since the friction force between the joints is greater, if the pressure is kept constant for a predetermined time in the process during joining, a “slip” occurs between the resonator and the first work piece during that time. Therefore, there is a possibility that it cannot be joined well. In particular, when the base material of the second workpiece is soft, the ultrasonic vibration is absorbed, and similarly, no “slip” occurs between the first and second workpieces. It is also conceivable that the second workpiece cannot be joined.

  Therefore, in order to cause “slip” necessary for joining between the first and second objects to be joined, it is necessary to perform control to change the value of the set pressure according to the joining state of both objects to be joined. is there.

  As a specific example of performing ultrasonic vibration bonding by changing and controlling the value of the set pressure as described above, there is Patent Document 1. The specific method for controlling the applied pressure in the ultrasonic vibration welding apparatus of Patent Document 1 is that the operator operates the operation panel to set the welding start weight setting value, the parallel pressure setting value, the first weight pressure setting value, 2) the pressure setting value, the primary joining time of the vibrator, the slope of the pressure change until the second weighting pressure setting value is reached from the first weighting pressure setting value according to the physical properties of the part to be joined, such as the size and material, etc. Input and set. And ultrasonic vibration joining is performed under the load by the control according to the input set value.

Japanese Patent No. 3447798 (paragraphs 0009, 0017 to 0025, FIG. 2)

In the apparatus of Patent Document 1, an open loop control is performed in which an operator inputs and sets an appropriate pressure for each predetermined time from the start to the end of joining. Since this method is not feedback control in which the joining state in the joining process between the joined objects by the set value is fed back to the device, once the set value is set and input, the state and adsorption of the joined object flowing in mass production In the held condition, the effect of unstable factors such as surface contamination, foreign object biting, and resonator and stage wear cannot be absorbed, resulting in a high defect rate and a decrease in yield. is there.

  Further, in the case of the open loop control, since the end of joining of both objects to be joined is determined by a predetermined elapsed time from the start of joining, the actual factors such as the above unstable elements for each object to be joined are used. There is a possibility that the end of joining of the objects to be joined will deviate from the set end. In this case, if the actual joining end is slower than the set joining end, the joining of the objects to be joined is incomplete, and if the actual joining end is earlier than the set joining end, Extra ultrasonic vibration energy is applied to the object, which leads to destruction and damage of the object to be joined.

  Therefore, every time the new surface of the surface of the object to be bonded increases, the bonding area increases. If the bonding area increases, the bonding force between the objects to be bonded also increases. And if the joining force of to-be-joined objects increases, the magnitude | size of the "slip" between to-be-joined objects will attenuate | damp. Therefore, in order to generate “slip” of a predetermined magnitude between the objects to be joined, it is necessary to increase the applied ultrasonic vibration energy in order to keep the vibration amplitude of the resonator constant.

  However, if the ultrasonic vibration energy is continuously applied to cause the predetermined “slip” between the objects to be bonded even though the bonding between the bonding parts of both objects is sufficiently advanced, Excess ultrasonic vibration energy is applied to the bonded portion of the object and both objects to be bonded, and the bonded portion and objects to be bonded of both objects are broken or damaged. In particular, the damage is concentrated in a weak part. For example, if the joint is a semiconductor (Si) bump (electrode), a crack (crack) is formed in the vicinity of the under barrier metal at the boundary between Si and the bump. Such damage may occur.

Furthermore, in the apparatus of Patent Document 1, the pressure is controlled in order to cause “slip” between the objects to be bonded. However, the control only with the pressure is sufficient to stabilize the space between the objects to be bonded. It is difficult to cause “slip”, and it is also considered that optimum “slip” for joining is not generated between objects to be joined due to unstable elements for each object to be joined. Therefore, in order to generate a stable “slip” between the objects to be bonded, the pressing force is controlled according to the bonding state of both objects to be bonded, and the vibration amplitude of the objects to be bonded is held at a predetermined set value. In addition, it is necessary to control the ultrasonic vibration energy applied to the workpiece.

Then, an object of this invention is to provide the ultrasonic vibration joining method and ultrasonic vibration joining apparatus which can be joined stably and reliably, without damaging a to-be-joined object.

  In order to solve the above-described problems, an ultrasonic vibration bonding method according to the present invention includes ultrasonic vibration by applying ultrasonic vibration energy from a vibrator while pressing a plurality of stacked objects to be bonded by a pressing unit. In an ultrasonic vibration joining method for joining ultrasonic wave vibrations to a plurality of superposed objects to be joined to each other, the ultrasonic waves to the resonator by an energy amount detection means. While detecting vibration energy, the amplitude of the resonator is detected by a resonator amplitude detecting means, and from the start of bonding, while the pressure applied by the pressurizing means to the plurality of objects to be joined is monotonously increased, The amplitude of the resonator by the resonator amplitude detection unit is set in advance from the start of bonding until the ultrasonic energy by the energy amount detection unit suddenly decreases. Held in the set value, it is characterized by attenuating the amplitude of the resonator the after rapid decrease of the ultrasonic energy by said energy amount detecting means (claim 1).

  Further, the ultrasonic vibration joining method according to the present invention is characterized in that the set value of the amplitude of the resonator is obtained in advance for each kind of the object to be joined (Claim 2). .

  Further, the device formed by the ultrasonic bonding method according to claim 1 or 2 is characterized in that the bonded material is a substrate, a wafer, a chip obtained by dividing the substrate or the wafer, a semiconductor, or a MEMS device ( Claim 3).

  The ultrasonic vibration bonding apparatus according to the present invention includes a resonator that vibrates ultrasonically by applying ultrasonic vibration energy from a vibrator while pressurizing a plurality of objects to be joined by a pressurizing unit. In an ultrasonic vibration bonding apparatus that transmits ultrasonic vibrations to a plurality of objects to be bonded to bond the objects to be bonded together, a drive control unit that controls the pressurizing unit and the vibrator, and the vibrator Energy amount detecting means for detecting the ultrasonic vibration energy and resonator amplitude detecting means for detecting the amplitude of the resonator, wherein the drive control means is applied to the plurality of superimposed objects to be joined. A pressurizing control unit that controls the pressurizing unit so that the pressure monotonously increases, and the resonator amplitude detecting unit until the ultrasonic energy by the energy amount detecting unit rapidly decreases. And a vibrator control unit that controls the vibrator so that the amplitude of the resonator is attenuated after the ultrasonic energy is suddenly decreased by the energy amount detection unit by holding the amplitude of the resonator according to the preset value. (Claim 4).

  According to the first and fourth aspects of the present invention, it is possible to determine the end of bonding by detecting ultrasonic vibration energy. That is, when the bonding of the objects to be bonded is completed, the bonding force at the bonding surface between the objects to be bonded becomes large, and therefore, between the resonator and the first object to be bonded (or between the second object to be bonded and the stage). The ultrasonic vibration causes a force greater than the maximum static frictional force between the resonator and the first workpiece (or between the second workpiece and the stage) to be applied to the resonator and the first workpiece. The friction coefficient between the objects (or between the second workpiece and the stage) shifts from the static friction coefficient to the dynamic friction coefficient. As a result, a “slip” occurs between the resonator and the first workpiece (or between the second workpiece and the stage). Therefore, when ultrasonic vibration energy is monitored, when a “slip” between the resonator and the first object to be joined (or between the second object to be joined and the stage) starts to occur, the load applied to the resonator is reduced. Since it becomes smaller, the ultrasonic vibration energy decreases rapidly. Therefore, it can be determined that the end of joining is detected by detecting when the ultrasonic vibration energy suddenly decreases.

  In addition, the pressurizing force is increased from the start of joining, and the vibration amplitude of the resonator is maintained at a predetermined set value until the ultrasonic vibration energy, which is a signal from the start of joining to the end of joining, suddenly decreases. A stable “slip” large enough for joining can be produced between the joints. Therefore, a new surface appears between the joints, and both objects to be joined can be reliably joined.

  Furthermore, after the ultrasonic vibration energy suddenly decreases, the joining of the objects to be joined has been completed, so that it is possible to add extra ultrasonic vibration energy to the joint and the base material by attenuating the amplitude of the resonator. This can prevent the destruction of the object to be joined and the like.

  According to invention of Claim 2, since the amplitude of a resonator can be set for every kind of to-be-joined object, favorable joining can be performed for every kind of to-be-joined object.

  According to the invention of claim 3, it is possible to provide a novel device having the same effect as that of the invention of claim 1 or 2.

  An embodiment of the present invention will be described with reference to FIGS. 1 is a schematic configuration diagram of an ultrasonic vibration bonding apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are ultrasonic vibration energy, vibration amplitude of a resonator, from start to end of bonding of an object to be bonded, FIG. 2 is a state transition diagram of the magnitude of “slip” between the objects to be joined and the applied pressure. FIG. 2 shows a case where the vibration amplitude of the resonator is maintained at a predetermined value even after the ultrasonic vibration energy is lowered. This is a case where the vibration amplitude of the resonator is decreased after the vibration energy is lowered. In the present embodiment, an apparatus for bonding the chip 20 as the first object to be bonded and the substrate 22 as the second object to be bonded is taken as an example.

(Device configuration)
As shown in FIG. 1, the ultrasonic vibration bonding apparatus according to the present embodiment includes a bonding mechanism 27 including a vertical driving mechanism 25, a head unit 26, and a stage 10 that sucks and holds a substrate 22 that is a second bonded object, The alignment unit 28 includes the stage table 12 and the position recognition unit 29, the gantry 35, the column 13 standing on the gantry 35, the gantry frame 34 that moves up and down along the column 13, the conveyance unit 30, and the control device 31. The

The vertical drive mechanism 25 and the head part 26 of the joining mechanism 27 function as the “pressurizing means” of the present invention. The vertical drive mechanism 25 converts the rotation of the vertical drive motor 1 through the bolt / nut mechanism 2 to the head portion 26 guided by the vertical guide 3 by converting it into a vertical motion, and transmits the head portion 26 up and down. It is supposed to be moved. As the vertical drive motor 1, for example, a servo motor based on torque control is preferably used.

Further, in the head unit 26, the vibrator 8 is joined to the resonator 7 in order to efficiently apply ultrasonic vibration energy to the article to be joined when the vibrator 8 is vibrated by applying voltage and current. The resonator 7 includes a suction mechanism (not shown) for holding the chip 20 as the first bonded body, and holds the chip 20 by this suction mechanism. The resonator 7 is installed in the resonator holding portion 6 that can hold the resonator 7 without disturbing the vibration of the resonator 7, and is guided in the vertical direction by the head escape guide 5. The resonator 7 cancels its own weight and is applied to the pressure detection means 32 and the vertical drive mechanism 25 for detecting the pressure while being pulled by the head weight counter 4 for pressing against the pressure detection means 32. is set up.

The head unit 26 includes a head height detecting unit 24 so that the head height can be detected. The head height detection means 24 may be either a contact type sensor or a non-contact type sensor. Further, the vertical drive mechanism 25 is connected to the gantry frame 34.

Next, the alignment unit 28 will be described. The stage table 12 of the alignment unit 28 is configured by a translational and rotational movement axis for adjusting the position of the substrate 22 so that the metal pad 22a of the substrate 22 corresponds to a predetermined metal protrusion 20a of the chip 20. The Further, the stage 10 is provided with a suction mechanism (not shown) for holding the substrate 22. Here, as a suction mechanism of the resonator 7 and the stage 10, a mechanism using vacuum suction or electrostatic suction may be used.

The position recognizing unit 29 includes upper and lower mark recognizing means 14 for recognizing the position recognizing marks on the chip 20 and the substrate 22 respectively, and the recognizing means moving for moving the upper and lower mark recognizing means 14 horizontally and / or up and down. A table 15 is provided. A resonator amplitude detecting means 33 is provided at the tip of the upper and lower mark recognizing means 14, and it can be moved to an arbitrary position by the recognizing means moving table 15 and the vibration amplitude of the resonator 7 can be measured. For example, a laser Doppler measuring device can be used as the resonator amplitude detection unit 33. If the resonator amplitude detection unit 33 cannot be installed at the tip of the upper / lower mark recognition unit 14, it may be installed separately from the upper / lower mark recognition unit 14. .

The transport unit 30 includes a chip supply device 16 that transports the chips 20 and a chip tray 17, and a substrate transport device 18 that transports the substrate 22 and a substrate transport conveyor 19.

The control unit 31 controls the entire apparatus and includes an operation unit, and includes an ultrasonic vibration energy control unit 31a, a resonance amplitude control unit 31b, a pressurization control unit 31c, and a recording unit 31d.

  The ultrasonic vibration energy control unit 31a functions as the “ultrasonic vibration energy detection unit” of the present invention, the “drive control unit” that controls the vibrator 8, and the “vibrator control unit”. Since the ultrasonic vibration energy can be detected by the product of the applied voltage to the vibrator 8 and the current with respect to the applied voltage, the ultrasonic vibration energy is controlled by the ultrasonic vibration energy control unit 31a. May be performed, the applied current may be changed, and both the applied voltage and current may be controlled.

The resonance amplitude control unit 31b performs control so that the vibration amplitude of the resonator 7 detected by the resonator amplitude detection means 33 or the magnitude of “slip” between the objects to be joined is held at a predetermined value.

The pressurization control unit 31 c controls the torque of the vertical drive motor 1 by a signal from the pressurizing force detection unit 32 and controls the pressurizing force related to the joining. In addition, the recording unit 31d records the set value of the amplitude of the resonator 7 obtained in advance for each type of object to be bonded.

A plurality of metal protrusions 20 a are formed on the bonding surface of the chip 20, and a plurality of metal pads 22 a such as solder are formed at positions corresponding to the metal protrusions 20 a on the bonding surface of the substrate 22.

(Joining operation)
Next, a series of operations for joining the metal protrusions 20a of the chip 20 and the metal pads 22a of the substrate 22 by ultrasonic vibration in order to mount the chip 20 on the substrate 22 will be described below.

First, an object to be joined is installed. That is, the chip 20 is supplied from the chip tray 17 to the resonator 7 by the chip supply device 16 of the transport unit 30, and is sucked and held on the resonator 7 by vacuum suction or the like. In addition, the substrate 22 is supplied from the substrate transfer conveyor 19 to the stage 10 by the substrate transfer device 18 and is sucked and held on the stage 10 by vacuum suction or the like. Then, the upper / lower mark recognition means 14 is inserted by the recognition means moving table 15 between the chip 20 and the substrate 22 whose holding surfaces are opposed to each other, and the alignment marks of the opposing chip 20 and the substrate 22 are placed on the upper / lower mark recognition means. 14 to recognize. When the alignment mark between the chip 20 and the substrate 22 is shifted, the position of the substrate 22 is moved in the parallel movement direction and / or the rotational movement direction by the stage table 12 with the chip 20 as a reference, and the position adjustment is performed.

Next, in a state in which the joining positions of the chip 20 and the substrate 22 are aligned, the head unit 26 is lowered by the vertical drive mechanism 25, and the predetermined metal protrusion 20a of the chip 20 and the predetermined metal of the substrate 22 corresponding thereto. Adjustment is performed so that the pad 22a is brought into contact with the pad 22a and a predetermined pressure is applied. Here, the position of the head portion 26 in the height direction is detected by the head height detecting means 24. Further, the contact timing between the chip 20 and the substrate 22 is detected by the pressure detection means 32.

Then, ultrasonic vibration bonding is started in a state where a predetermined pressure is applied to the chip 20 and the substrate 22 by the vertical drive motor 1. During bonding, the ultrasonic vibration energy, the resonance amplitude of the resonator 7 and the applied pressure are monitored, and the control device 31 controls the ultrasonic vibration energy, the resonance amplitude of the resonator 7 and the applied pressure. The control method will be described with reference to FIGS.

2 and 3, A is the applied pressure, B is the vibration amplitude of the resonator 7, C is the magnitude of “slip” between the chip 20 and the substrate 22, and D is the ultrasonic vibration energy. Show. 2 and 3 are time (seconds). In the vertical axis, the unit of A applied pressure is (N), the vibration amplitude of the resonator 7 of B, and “ The unit of magnitude of “slip” is (μm), and the unit of ultrasonic vibration energy of D is (W). Moreover, time t = 0 in FIG. 2 and FIG. 3 shows a joining start time.

Since the bonding surfaces of the chip 20 and the substrate 22 have small unevenness and a difference in height at a plurality of bonding portions, the bonding area gradually increases in the process of bonding. Then, since the bonding force between the chip 20 and the substrate 22 gradually increases, when the magnitude of “slip” between the chip 20 and the substrate 22 is detected by the resonator amplitude detection unit 33, the gap between the chip 20 and the substrate 22 is detected. “Slip” gradually decreases. Then, the bonding force between the chip 20 and the substrate 22 becomes larger than the frictional force between the resonator 7 and the chip 20 (or between the substrate 22 and the stage 10), and the resonator 7 and the chip 20 (or the substrate). When a force greater than the maximum static frictional force between the resonator 7 and the chip 20 (or between the substrate 22 and the stage 10) is applied between the resonator 7 and the chip 20 between the resonator 7 and the chip 20 The friction coefficient (or between the substrate 22 and the stage 10) shifts from the static friction coefficient to the dynamic friction coefficient, and “slip” occurs between the resonator 7 and the chip 20 (or between the substrate 22 and the stage 10). Become. Therefore, the ultrasonic vibration energy is not sufficiently transmitted to the chip 20 and the substrate 22, and the bonding does not proceed.

Therefore, as shown by A in FIGS. 2 and 3, when the applied pressure is increased, the frictional force between the resonator 7 and the chip 20 (or between the substrate 22 and the stage 10) increases with time from the start of bonding. The “slip” between the resonator 7 and the chip 20 (or between the substrate 22 and the stage 10) is suppressed, ultrasonic vibration energy is transmitted to the chip 20, and the “slip” between the chip 20 and the substrate 22 is large. Therefore, a new surface appears on the bonding surface between the chip 20 and the substrate 22, and the bonding area becomes larger.

However, as described above, the “slip” between the chip 20 and the substrate 22 decreases as the bonding area increases. Accordingly, in order to increase the applied pressure and increase the ultrasonic vibration energy, the magnitude of “slip” between the chip 20 and the substrate 22 is maintained at a predetermined value as indicated by C in FIGS. Further, the ultrasonic vibration energy control unit 31a and the resonance amplitude control unit 31b are controlled so that the vibration amplitude of the resonator 7 is kept constant at a preset value as shown in B in FIGS. I do.

Specifically, the applied pressure is increased as indicated by A in FIGS. 2 and 3, a predetermined voltage is applied to the vibrator 8, and the phase of the voltage and the voltage are applied to the vibrator 8 when the voltage is applied. The phase of the flowing current is detected, the phase of the voltage applied to the vibrator 8 and the phase of the current match, and the vibration amplitude of the resonator 7 and the chip 20 as shown by B and C in FIGS. The current of the vibrator 8 is controlled so that the magnitude of the “slip” between the first and second substrates 22 is maintained at a predetermined value. As an example, the voltage applied to the vibrator 8 is set within the range of 0V to 10V. Further, although there are differences depending on the member, area, etc., as an example, the magnitude of “slip” between the chip 20 and the substrate 22 has an amplitude of about 0.1 μm to 0.5 μm.

The set value of the vibration amplitude of the resonator 7 is read from the recording unit 31d when the vibration amplitude of the resonator 7 is measured in advance according to the type of the object to be joined and is already recorded in the recording unit 31d. The vibration energy control unit 31a and the resonance amplitude control unit 31b can be set. Further, as described above, when the control is performed by changing the current while keeping the applied voltage constant, the optimum condition of the current with respect to the applied voltage value is measured in advance and recorded in the recording unit 31d. Even if the vibration amplitude of the resonator 7 is not controlled by the unit 31b, the applied voltage value and the optimum current value corresponding to the applied voltage value can be read and set from the recording unit 31d.

Further, when the control is performed so that the vibration amplitude of the resonator 7 is held at a preset value by applying a voltage to the vibrator 8 as described above, the ultrasonic vibration energy control unit 31a simultaneously performs the control. For example, when the ultrasonic vibration energy is detected by measuring the value of the current flowing through the vibrator 8, the ultrasonic vibration energy gradually increases as indicated by D in FIGS.

When the ultrasonic vibration energy is continuously monitored, it is possible to detect the end of bonding of the chip 20 and the substrate 22. When the bonding of the chip 20 and the substrate 22 is completed, the “slip” between the chip 20 and the substrate 22 does not occur as described above, and therefore, the resonator 7 and the chip 20 to be bonded (or the substrate 22 and the stage). 10)), the load applied to the resonator 7 is reduced, and the ultrasonic vibration energy rapidly decreases as indicated by D in FIG. Therefore, it can be determined that the time when the ultrasonic vibration energy is rapidly reduced is the end of the joining.

Even after the sudden decrease of the ultrasonic vibration energy, if the control to keep the vibration amplitude of the resonator 7 constant as shown in FIG. 2 is continued, an extra force is applied to the chip 20 and the substrate 22. Will cause destruction and damage. Therefore, after the sudden decrease of the ultrasonic vibration energy, in order to prevent damage and destruction to the chip 20 and the substrate 22, the ultrasonic vibration energy control unit 31a, the resonance amplitude control unit 31b, and the pressurization control unit 31c are shown in FIG. As shown, control is performed to reduce the vibration amplitude of the resonator 7. Further, control may be performed to reduce the vibration amplitude of the resonator 7 and reduce the applied pressure.

Then, after the ultrasonic vibration bonding is completed and the vibration amplitude and the applied pressure of the resonator 7 are reduced to predetermined values, when the adsorption of the chip 20 is released, the chip 20 is mounted on the substrate 22 side on the stage. Remain in. This is again discharged to the substrate transfer conveyor 19 by the substrate transfer device 18, and the series of operations ends.

Therefore, according to the above-described embodiment, before the ultrasonic vibration energy is suddenly reduced, the bonding force between the chip 20 and the substrate 22 is controlled by increasing the pressure and holding the vibration amplitude of the resonator 7 at a constant value. Since “slip” occurs between the two joints, a new surface appears between the joints, and both the objects to be joined can be joined.

Further, since the vibration amplitude of the resonator 7 is attenuated after the ultrasonic vibration energy is suddenly reduced, it is possible to prevent excessive ultrasonic vibration energy from being applied to the chip 20 and the substrate 22 that have been joined, and to destroy or damage the object to be joined. Can be avoided.

Furthermore, since the control unit 31 includes the recording unit 31d, the optimal vibration amplitude setting value of the resonator 7, the voltage value applied to the vibrator 8, and the optimum value corresponding to the voltage value are determined for each type of object to be joined. When the current value or the like is measured and recorded in advance, the setting value is read from the recording unit 31d and set. By using recording, good bonding can be easily performed.

In addition, according to the above-described embodiment, effective bonding can be performed even for a device such as a semiconductor device or a MEMS device that needs to bond electrodes composed of fine bumps with high accuracy. A good device can be provided.

The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the present invention.

For example, in order to obtain “slip” between the chip 20 and the substrate 22, a plurality of resonator amplitude detection means 33 may be provided to measure each vibration amplitude of the chip 20 and the substrate 22 at the same time. After the vibration amplitudes of the chip 20 and the substrate 22 are measured in order by the amplitude detecting means 33, the amplitude difference on the same time axis can be calculated. For example, when the chip 20 and the substrate 22 are thin and it is difficult to provide a plurality of resonator amplitude detection means 33 from one side, they can be individually installed from both sides.

The resonator amplitude detection means 33 is not limited to the laser Doppler measurement device described above, and may be an eddy current type, capacitance type, light irradiation type or sound wave type detection means. These methods may also be used for the upper and lower mark recognition means 14. Although the detection means of these methods are inferior in terms of resolution and speed compared to laser Doppler measuring instruments, the amplitude detection means of the present invention is accurate enough to determine whether or not the amplitude is the target value. Any method may be used. In addition, these methods are two orders of magnitude cheaper than laser Doppler measuring instruments, and are small detection means, so that measurement is possible even in complicated and complicated places.

Furthermore, the magnitude of the “slip” between the chip 20 and the substrate 22 is an unstable factor even if the actual “slip” is not measured by the resonator amplitude detection means 33 as in this embodiment. If not, it can be estimated by the following procedure. For example, if the second object to be bonded is stably adsorbed and held on the stage, the amplitude of the first object to be measured is measured as the vibration object to be measured without measuring the amplitude of the second object to be bonded. Can be achieved. Further, if the friction between the first object to be bonded and the resonator 7 is stable and vibration transmission is stable, this can be achieved by measuring the amplitude of the resonator 7 as the vibration object to be measured. Further, since the amplitude of the vibrator can be estimated from the return current value with respect to the output current applied to the piezoelectric element of the vibrator, the increase in the junction area can be achieved by reading the return current value with respect to the output current of the vibrator. In addition, the amplitude of the vibrator can be estimated from the voltage value and / or current value applied to the piezoelectric element of the vibrator, and the current value and voltage value to the vibrator are controlled using the result of the amplitude value. You may carry out by control.

  In the above-described embodiment, the torque control method of the vertical drive motor 1 is shown as the pressurizing unit. However, the pressurizing unit using the fluid pressure by the air cylinder may be used.

In the above-described embodiment, the stage table 12 on the alignment unit 28 side is provided with a translational and rotational movement axis for horizontal position adjustment, and the head unit 26 side is provided with a vertical axis for vertical position adjustment. However, the movement axis and the lifting axis of the parallel movement and the rotation movement may be combined in any way on the head part 26 side and the alignment part 28 side, or may overlap. Further, the arrangement direction may be appropriately changed, such as left and right arrangement or diagonal, without arranging the head unit 26 and the stage table 12 vertically.

  Further, the holding means for the chip 20 and the substrate 22 is not limited to suction holding such as electrostatic suction or vacuum suction, but may be clamp holding and grip holding, or may be held by mixing them. Moreover, in the case of a 2nd to-be-joined object, you may only put on the stage 10. FIG.

Further, the resonator heater 9 and the stage heater 11 may be incorporated in the resonator 7 and the stage 10 as shown in FIG. In this case, since ultrasonic vibration bonding can be performed while heating the object to be bonded, it is not necessary to give excessive ultrasonic vibration energy to the object to be bonded, and the destruction and damage of the object can be prevented more. it can.

In the joining process, the applied pressure may be increased in proportion to the joining area, or may be increased by an arbitrary curve. Moreover, you may hold | maintain to a predetermined value.

Further, the number of objects to be joined is not limited to two, and may be three or more. The objects to be bonded are not limited to semiconductors such as the chip 20 and the substrate 22 described above, but may be other materials. In addition, gold, aluminum, copper, or the like is suitable for the joint, but any other metal or other metal can be used as long as it can be joined by ultrasonic vibration.

Further, the chip 20 may have any form such as a wafer. Further, the metal protrusions may have a plurality of individual shapes, a shape in which a certain region is confined and connected, or the entire surface may be a bonding surface.

It is a schematic block diagram of the ultrasonic vibration joining apparatus in one embodiment of this invention. FIG. 2 is a state transition diagram in the case where the vibration amplitude of the resonator is kept constant even after a sudden decrease in ultrasonic vibration energy in the joining process by the apparatus of FIG. 1. FIG. 2 is a state transition diagram when the vibration amplitude of the resonator is decreased after the ultrasonic vibration energy is rapidly decreased in the joining process by the apparatus of FIG. 1.

Explanation of symbols

1 …… Vertical drive motor (pressurizing means)
2 ... Bolt / nut mechanism (pressurizing means)
3 …… Up and down guide (pressurizing means)
4 …… Head weight counter (pressurizing means)
5 …… Head escape guide (pressurizing means)
6 …… Resonator holder (pressurizing means)
7 …… Resonator (Pressurizing means)
8 …… Vibrator (pressurizing means)
20 …… Chip (first object to be joined)
22 …… Substrate (second object to be joined)
25 …… Up-down drive mechanism (pressurizing means)
26 …… Head (Pressurizing means)
31... Control device 31a... Ultrasonic vibration energy control section (energy amount detection means, drive control means, vibrator control section)
31b: Resonator amplitude control unit 31c: Pressurization control unit 31d: Recording unit 32: Applied pressure detection means 33: Resonator amplitude detection means

Claims (4)

From the resonator that ultrasonically vibrates by the application of ultrasonic vibration energy from the vibrator while holding and holding the plurality of stacked objects to be bonded by the pressurizing means, the ultrasonic waves are applied to the plurality of stacked objects to be bonded. In the ultrasonic vibration bonding method for transmitting vibration and bonding the objects to be bonded together,
While detecting the ultrasonic vibration energy to the resonator by the energy amount detection means,
Detecting the amplitude of the resonator by means of a resonator amplitude detector;
From the start of joining, while monotonously increasing the pressure applied by the pressurizing means to the superposed multiple joined objects,
From the start of bonding until the ultrasonic energy by the energy amount detection means rapidly decreases, the amplitude of the resonator by the resonator amplitude detection means is held at a preset setting value, and the energy amount detection means An ultrasonic vibration joining method, wherein the amplitude of the resonator is attenuated after the ultrasonic energy is suddenly reduced.   The ultrasonic vibration bonding method according to claim 1, wherein the set value of the amplitude of the resonator is obtained in advance for each type of the object to be bonded.   The device formed by the ultrasonic vibration bonding method according to claim 1, wherein the object to be bonded includes a substrate, a wafer, a chip obtained by dividing the substrate or the wafer, a semiconductor, or a MEMS device. device. From the resonator that ultrasonically vibrates by the application of ultrasonic vibration energy from the vibrator while holding and holding the plurality of stacked objects to be bonded by the pressurizing means, the ultrasonic waves are applied to the plurality of stacked objects to be bonded. In an ultrasonic vibration bonding apparatus that transmits vibration and bonds the objects to be bonded together,
Drive control means for controlling the pressurizing means and the vibrator;
Energy amount detecting means for detecting the ultrasonic vibration energy of the vibrator;
A resonator amplitude detecting means for detecting the amplitude of the resonator;
The drive control means includes
A pressurizing control unit that controls the pressurizing unit so that the pressurizing force to the plurality of objects to be joined is monotonously increased;
Until the ultrasonic energy by the energy amount detection unit rapidly decreases, the amplitude of the resonator by the resonator amplitude detection unit is held at a preset setting value, and the ultrasonic energy by the energy amount detection unit is maintained. And a vibrator control unit that controls the vibrator so that the amplitude of the resonator is attenuated after a sudden decrease.

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