JP2001127112A - Method for bonding semiconductor chip and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for bonding semiconductor chips by means of ultrasonic wave capable of materializing excellent management for quality control. SOLUTION: A bonding unit 20 of a flip-chip bonding apparatus 10 comprises a bonding head 24, a bonding tool 26 coming down from the bonding head 24, and an ultrasonic oscillator 28 integrally formed with the bonding tool 26. Further, the unit 20 has an ultrasonic wave outputting power and time setting circuit 30 and an ultrasonic wave oscillating circuit 32, and an ultrasonic wave oscillating mechanism is constituted with these circuits and the ultrasonic wave oscillator 28. A sensor 22 is a non-contact laser Doppler oscillator, and disposed in an optical sensitive manner to reflected light of the semiconductor chip 16. Bonding condition is judged by measuring difference in frequency of reflected light occurred by Doppler effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor chip bonding method and apparatus, and more particularly, to a semiconductor chip bonding method and apparatus capable of performing good bonding.

[0002]

2. Description of the Related Art A semiconductor device in which a semiconductor chip is mounted on a wiring board and further packaged is used for an electronic device. In this case, in a general mounting method of mounting a semiconductor chip on a wiring board with a pad (electrode) formation surface facing upward, the pad of the semiconductor chip is formed of an inner lead formed on the wiring board and, for example, Au. Wire bonding is performed using wires.

[0003] This wire bonding is performed using, for example, an automatic wire bonding apparatus. First, a wiring board on which a semiconductor chip is mounted is heated and pulled out from a tip end of a bonding wire drawing tool called a capillary. The Au wire is discharged by an electric torch to form an Au ball at the tip of the wire. Next, the Au ball is brought into contact with a pad on the semiconductor chip, and the capillary is compressed while applying ultrasonic energy to vibrate the capillary horizontally.

[0004] A wire bonding apparatus for performing wire bonding by applying ultrasonic energy is intended to always perform bonding in an optimum bonding state without being affected by surface conditions or disturbance of a semiconductor chip to be bonded. There has been proposed an ultrasonic oscillator for an ultrasonic bonder having a configuration in which an oscillation output waveform in the medium is monitored and feedback control is performed so as to obtain an optimum waveform (Japanese Patent Application Laid-Open No. 2-58844).

This ultrasonic oscillator for an ultrasonic bonder vibrates a vibrator by an ultrasonic oscillation output / time setting circuit and an ultrasonic oscillation circuit, and digitally samples an ultrasonic oscillation output waveform during bonding. A / D conversion circuit, an optimum waveform setting circuit for inputting and setting an optimum bonding output waveform in advance, and a comparison circuit for comparing the sampled ultrasonic oscillation output waveform during bonding with the optimum output waveform, Is fed back to the ultrasonic oscillation output / time setting circuit.

In this case, the detection of the output waveform during the progress of bonding is performed by the magnetostrictive element attached to the vibrator, and the output actually consumed for bonding can be detected. The specific configuration is not shown in the official gazette. For example, a mechanism for directly contacting a vibrator with a joint and detecting an output waveform of the vibrator,
In the case of the wedge bonding method, a mechanism is attached to the wedge that presses the wire and a mechanism for detecting the output waveform of the oscillator, or in the case of the above-described automatic wire bonding apparatus, the oscillator is attached to the capillary. A mechanism or the like for detecting the output waveform of the vibrator is assumed.

On the other hand, as a bonding method, there is a wireless bonding other than the wire bonding.
For example, so-called flip-chip bonding, in which a semiconductor chip is turned upside down and bumps are aligned with electrodes (pads) of a wiring board and mounted by face-down bonding, is widely used. Is performed. In this method, a plurality of formed bumps and pads are joined by a single bonding operation regardless of the number of the bumps and pads, without using wires as described above. Normally, a reflow method is used when a bump is formed from a solder material. However, when a bump is formed from an Au material as in the above-described wire bonding example, a heat welding method such as the reflow method cannot be adopted due to temperature conditions. Therefore, for example, a joining method using ultrasonic vibration has been proposed (JP-A-59-2088).
No. 44).

The flip-chip type semiconductor device manufactured in this manner can be said to be ideal from the viewpoint of miniaturization and high-density mounting of the device.

[0009]

In the above-described flip-chip bonding, it is conceivable to perform bonding using ultrasonic vibration as in the case of wire bonding. As described above, the heat welding method such as the reflow method is appropriate when a solder bump is used, but is not appropriate when a metal such as Au is used as a material for the bump, and even when a solder bump is used. This is because flip chip bonding also causes problems such as fatigue fracture of solder due to thermal stress.

However, techniques for monitoring the bonding state or controlling the bonding conditions to more optimum bonding conditions, such as the above-described ultrasonic oscillator for an ultrasonic bonder in wire bonding, have not yet been studied for flip chip bonding. Is the actual situation. Therefore, when the bonding operation is uniformly performed for a predetermined time, for example, the ultrasonic vibrator and the semiconductor chip are brought into contact with each other in a plane, so that the vibration of the ultrasonic vibrator is not completely transmitted to the semiconductor chip. This phenomenon becomes remarkable when the ultrasonic vibrator and the semiconductor chip slip, and the bonding operation is completed in a state where the bonding is insufficient and a defective product is generated. Or, conversely, if vibration continues for some reason even after the bonding is actually completed, stress will be generated at the joint and this will also lead to defective products.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when performing semiconductor chip bonding using ultrasonic waves, the bonding state is monitored and appropriate measures such as securing appropriate bonding conditions are ensured. Therefore, it is an object of the present invention to provide a semiconductor chip bonding method and apparatus using ultrasonic waves, which can realize good manufacturing quality control by adopting the method.

[0012]

SUMMARY OF THE INVENTION A semiconductor chip bonding method according to the present invention is a semiconductor chip bonding method for connecting a semiconductor chip to a member having a wiring pattern formed thereon using ultrasonic waves. The vibration waveform of the semiconductor chip is measured, and the bonding state is grasped from the measurement result (the invention according to claim 1). An apparatus used for such a semiconductor chip bonding method includes an ultrasonic oscillation output / time setting circuit for ultrasonically oscillating the semiconductor chip, an ultrasonic oscillation circuit and an ultrasonic oscillator (oscillation horn). A mechanism and a sensor for measuring a vibration waveform of the semiconductor chip are provided (the invention according to claim 7).

Here, the member on which the wiring pattern is formed broadly refers to not only a normal wiring board but also a wiring pattern formed product on which a semiconductor chip is mounted. For example, a suspension for mounting a head in a hard disk device corresponds to this, and a wiring pattern is formed on the suspension, and a head IC as a semiconductor chip is mounted.

By monitoring the vibration state of the semiconductor chip, for example, checking for changes in the vibration waveform between semiconductor device products, or comparing the vibration state with an ideal vibration state set in advance to determine whether the bonding state is good or bad. By grasping the situation and taking appropriate measures as necessary, good manufacturing quality control in the semiconductor device manufacturing process can be realized.

The sensor used for this purpose is not particularly limited. For example, when a change in the frequency of light reflected from a measurement object due to the Doppler effect is measured using a laser Doppler vibrometer as a non-contact vibrometer, It is preferable that the measurement can be performed without contacting the semiconductor chip to be measured. Alternatively, a piezoelectric element (piezo element) may be attached to a measurement object as a contact-type vibrometer, and a change in current generated from the piezoelectric element may be measured.

In this case, it is conceivable that the vibration state of the ultrasonic vibrator is detected by a sensor instead of the semiconductor chip. However, as described above, due to the configuration of the device,
The semiconductor chip does not directly receive the vibration of the ultrasonic vibrator, but the vibration generated by the ultrasonic vibrator while being pressed by the semiconductor chip suction and transfer tool is transmitted to the semiconductor chip via the semiconductor chip suction and transfer tool. At this time, the semiconductor chip suction and transfer tool and the semiconductor chip are both brought into contact with each other on flat surfaces, so that a slip may occur. Further, the object to which vibration is applied is, for example, in the case of a flip chip, not a base substrate of a semiconductor chip but a bump formed on the surface of the base substrate, so to speak, the vibration is applied to the bump via the base substrate. Will be communicated. Therefore, the vibration waveform of the ultrasonic vibrator cannot completely become the vibration waveform of the semiconductor chip. In particular, when the semiconductor chip suction and transfer tool and the semiconductor chip slip, the vibration waveforms of both of them are generated. It is conceivable that the gap becomes significant. In such a state, it is not appropriate to detect the vibration state of the ultrasonic vibrator by a sensor. On the other hand, it is difficult to directly measure the vibration of the bump as a joining portion due to the configuration of the apparatus, and the Since it is not possible to measure the vibration of all of the bumps to be formed, it is preferable to detect the vibration state of the semiconductor chip with a sensor as in the present invention in order to monitor the bonding state as accurately as possible.

Further, in the semiconductor chip bonding method and apparatus according to the present invention, instead of the semiconductor chip,
The member on which the wiring pattern is formed may be ultrasonically vibrated, and the vibration waveform of the member on which the wiring pattern is formed may be measured (the invention according to claims 2 and 8). For example, when it is not always preferable to apply ultrasonic vibration to the semiconductor chip for reasons such as a circuit configuration, the effects of the present invention can be suitably exhibited. In this case, when the vibration from the vibrator is primarily transmitted to a stage other than the member on which the wiring pattern is formed, for example, to a stage on which the member on which the wiring pattern is formed, the vibration state of the stage is detected. May be. Further, the vibration of the member or the stage on which the wiring pattern is formed may be detected by a sensor in a state where the ultrasonic vibration is applied to the semiconductor chip instead of the member on which the wiring pattern is formed by the ultrasonic vibrator. That is, at the end of bonding, the semiconductor chip and the member on which the wiring pattern is formed are joined and integrated, and the phenomenon in which the vibration state of the member on which the wiring pattern is formed or the stage is significantly changed is used. The bonding state is determined by monitoring the vibration state of the member or stage on which is formed.

In order to utilize the information of the vibration state monitored by the sensor as described above, the semiconductor chip bonding method according to the present invention sets the optimum vibration waveform corresponding to the optimum bonding state in advance, and A waveform is compared with the vibration waveform (the invention according to claim 3), and as an apparatus therefor, the ultrasonic vibration mechanism includes an A / D to which an analog vibration waveform obtained by the sensor is input. A conversion circuit, an optimal digital waveform setting circuit for presetting an optimal digital oscillation waveform corresponding to an optimal bonding state, and a comparison for comparing the digital oscillation waveform output from the A / D conversion circuit with the optimal digital oscillation waveform Circuit (claim 9), the digital vibration waveform can be compared with the optimal digital vibration waveform. Accordingly, it is possible to properly treat perform a more precise judgment for bonding state.

In this case, the semiconductor chip bonding method according to the present invention compares the optimum vibration waveform with the vibration waveform, displays the comparison result on a display device, and, when the comparison value deviates from a predetermined reference. The ultrasonic vibration mechanism displays a signal output from the comparison circuit and deviates from a preset reference as an apparatus for displaying an abnormality (the invention according to claim 4). In a case where the apparatus further includes a display device for displaying an abnormality in the case (the invention according to claim 10), the display of the display device enables a more accurate determination of the bonding state.

Further, in this case, the semiconductor chip bonding method according to the present invention further comprises stopping the semiconductor chip bonding apparatus (the invention according to claim 5). A control unit for controlling the operation / stop of the semiconductor chip bonding apparatus including the mechanism is further provided, and a signal indicating an abnormality of the display device is input to the control unit to stop the semiconductor chip bonding apparatus. Invention according to item 5), it is possible to avoid a situation in which defective products that are not completely bonded are continuously generated, and it is possible to perform an appropriate abnormality treatment while the apparatus is stopped.

Further, in this case, the semiconductor chip bonding method according to the present invention is to feedback-control the vibration waveform based on a result of comparison between the optimum vibration waveform and the vibration waveform (the invention according to claim 6). As a device therefor, the signal output from the comparison circuit is further fed back to the ultrasonic oscillation output / time setting circuit to perform feedback control of the oscillation waveform (the invention according to claim 12). By always maintaining the bonding state appropriately, it is possible to suppress the occurrence of a product having a bonding failure.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a semiconductor chip bonding method and apparatus according to the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings by taking a flip chip as an example. explain. First, as shown in FIG. 1, a flip-chip bonding apparatus 10 according to a first example of the present embodiment has a wiring board (a member on which a wiring pattern is formed) with a surface on which pads 11 are formed facing upward. A stage 14 on which the semiconductor chip 12 is mounted, and a semiconductor chip 16
A bonding unit 20 for transporting with the surface on which the bumps 18 are formed face down and the back side adsorbed and held from above, and abutted against the wiring board 12 for bonding, with the bonding unit 20 turned upside down; , And a control unit (not shown) for controlling the above operation, and a sensor 22.

The bonding unit 20 includes a bonding head 24, a bonding tool 26 hanging from the bonding head 24, and an ultrasonic transducer 28 provided integrally with the bonding tool 26. The bonding unit 20 has a suction and transfer mechanism (not shown) for sucking and transferring the semiconductor chip 16, and presses the bonding tool 26 to release the semiconductor chip 1.
6 has a pressure mechanism (not shown) for contacting the wiring board 12 with the wiring board 12 and pressurizing the pressure to a predetermined pressure.

An ultrasonic oscillation output / time setting circuit 30 for ultrasonically oscillating the semiconductor chip 16 and an ultrasonic oscillation circuit 32 are provided as units in the control section. The ultrasonic oscillation output / time setting circuit 30 and the ultrasonic oscillation circuit 32
And the above-described ultrasonic vibrator 28 constitute an ultrasonic vibration mechanism. In this case, the sensor 22 is a laser Doppler vibrometer, which is a non-contact vibrometer, and the semiconductor chip 16
Are arranged so as to be able to receive the reflected light from the side surface 16a of the light-emitting device, and measure the change in the frequency of the reflected light due to the Doppler effect.

A flip-chip bonding method using the flip-chip bonding apparatus 10 according to the first example of the present embodiment configured as described above will be described below.
First, a predetermined ultrasonic oscillation output and time are preset using an input mechanism (not shown).
Enter and set. Next, the wiring board 12 is placed on the stage 14, the semiconductor chip 16 is sucked by the bonding unit 20, transported to a predetermined position, and the bonding tool 26 is pressed to release the semiconductor chip 1.
The bumps 18 formed on the wiring board 6 and the pads 11 formed on the wiring board 12 are positioned so as to be in contact with each other. In this state, the bonding tool 26 is further pressed to press the semiconductor chip 16 to a predetermined pressure. Then, the ultrasonic oscillation circuit 32 is operated by the ultrasonic oscillation output / time setting circuit 30, and the ultrasonic transducer 28 is ultrasonically vibrated. As a result, the vibration of the ultrasonic transducer 28 is transmitted to the semiconductor chip 16, the semiconductor chip 16 vibrates in the horizontal direction (the direction of the arrow in FIG. 1), and the bump 18 and the pad 11 are welded and bonded.

In the process of bonding the ultrasonic vibrator 28 by ultrasonic vibration, the vibration waveform of the semiconductor chip 16 is detected by the sensor 22 and monitored. Then, for example, the change of the vibration waveform between the bonded semiconductor device products is checked, or the quality of the bonding state is grasped by judging by comparing it with an ideal vibration state set in advance, and further, if necessary, the appropriate By taking appropriate measures, good manufacturing quality control in the semiconductor device manufacturing process can be realized.

Next, a flip chip bonding apparatus 34 according to a second example of the present embodiment will be described with reference to FIG. In the following examples, the same components as those of the flip-chip bonding apparatus 10 of the first example of the present embodiment are given the same reference numerals as those of the first example of the present embodiment. , The description of which may be omitted.

The flip chip bonding apparatus 34 according to the second example of the present embodiment is constituted by substantially the same components as the flip chip bonding apparatus 10 of the first example of the present embodiment. The points are different. That is, the ultrasonic vibrator 28 includes a support member 36 for supporting the stage 14 on which the wiring board 12 is mounted on a base (not shown).
Therefore, the wiring board 12 vibrates in the horizontal direction (the direction of the arrow in FIG. 2) via the support member 36.

The sensor 38 is a contact-type vibrometer, in which a piezoelectric element (piezo element) 40 is attached to the vibrating wiring board 12, and a change in current generated from the piezoelectric element 40 is measured. The second embodiment of the present embodiment configured as described above
According to the flip-chip bonding apparatus 34 and the method according to the example, the vibration waveform of the wiring board is detected and monitored by the sensor 38, and the quality of the bonding state is determined as in the case of the first example of the present embodiment. Is done.

Next, a flip chip bonding apparatus 42 according to a third embodiment of the present invention will be described with reference to FIG. The flip chip bonding apparatus 42 according to the third example of the present embodiment is similar to the flip chip bonding apparatus 42 of the present embodiment.
Although it is constituted by substantially the same components as the flip chip bonding apparatus 10 of the example, the following points are different.

That is, a rectangular semiconductor chip contact member 44 having a through hole 48 into which the bonding tool 26 is loosely inserted is provided separately from the bonding unit 20,
An ultrasonic vibrator 28 is provided to vibrate the semiconductor chip contact member 44. Semiconductor chip contact member 44
The through hole 48 is formed in a step shape, is enlarged and opens downward, and the opening is tapered (reference numeral 48a).
Formed. When the semiconductor chip 16 is pressed by the bonding tool 26, the semiconductor chip contact member 44 is configured to be urged by an operating mechanism (not shown) to lightly contact the outer periphery of the semiconductor chip 16 to grip the semiconductor chip 16.

Therefore, there is no possibility that the semiconductor chip 16 will be damaged due to excessive force acting on the outer periphery of the semiconductor chip 16. At this time, the semiconductor chip contact member 44
Of the semiconductor chip 1 is formed in a tapered shape.
6 can be smoothly accommodated in the opening, and the same bonding unit 20 and semiconductor chip contact member 44 can be used for different lots having different semiconductor chip dimensions.

The sensor 46 is a contact-type vibrometer, similar to the second example of the present embodiment, in which the piezoelectric element 40 is attached to the semiconductor chip contact member 44 which receives vibration, and the piezoelectric element 4
It is configured to measure a change in current emanating from zero. In this case, since the semiconductor chip 16 is gripped by the semiconductor chip contact member 44 as described above, the semiconductor chip 16 vibrates integrally with the semiconductor chip contact member 44 without slipping. Therefore, the first embodiment of the present embodiment
Also, as compared with the second example, the vibration waveform of the semiconductor chip contact member 44 corresponding to the actual bonding state can be detected and monitored.

According to the flip chip bonding apparatus 42 and the method according to the third example of the present embodiment configured as described above, the vibration waveform of the semiconductor chip contact member 44 is detected and monitored by the sensor 46, The quality of the bonding state is suitably determined. Next, a flip chip bonding apparatus 50 according to a fourth example of the present embodiment will be described with reference to FIGS.

The flip-chip bonding apparatus 50 according to the fourth embodiment of the present embodiment shown in FIG. 4 has the same configuration as the flip-chip bonding apparatus 10 of the first embodiment of the present embodiment and the bonding unit 20 and the like. However, the configurations of the ultrasonic vibration mechanism and the sensor 52 are different. That is, the ultrasonic vibration mechanism includes the ultrasonic vibrator 28, the ultrasonic oscillation output / time setting circuit 30, and the ultrasonic oscillation circuit 32, similarly to the flip chip bonding apparatus 10 of the first example of the present embodiment. In addition, it further has an optimum vibration waveform setting circuit 54, an A / D conversion circuit 56, a comparison circuit 58, and a display device 60. Here, the optimum vibration waveform setting circuit 54 accumulates and analyzes the data of the vibration waveform in each case of good or bad bonding condition from abundant operation results and finds the optimum vibration waveform immediately before the end of bonding when the bonding condition is good. , For inputting and setting the optimum vibration waveform. The control unit 62 controls the ultrasonic vibration mechanism and controls the entire operation of the flip chip bonding apparatus 50, the automatic loading of the wiring board 12 into the flip chip bonding apparatus 50, and the automatic unloading of the completed semiconductor device. Is provided.

A flip chip bonding method using the flip chip bonding apparatus 50 according to the fourth example of the present embodiment configured as described above will be described with reference to FIG. A predetermined ultrasonic oscillation output and time are previously input to an ultrasonic oscillation output / time setting circuit 30 using an input mechanism (not shown) and set (S10). Similarly, the optimum vibration waveform (optimal digital vibration waveform) is input to the optimum vibration waveform setting circuit 54 and set (S12).

Next, the control power supply is turned on to start the operation (S14). After the wiring board 12 is placed on the stage 14 by an automatic loading device (not shown) (S16), the semiconductor chip 16 is sucked by the bonding unit 20, transported to a predetermined position, and the bonding tool 26 is pressed down to the semiconductor chip 16. The bumps 18 to be formed and the pads 11 formed on the wiring board 12 are positioned so as to be in contact with each other (S18). In this state, the bonding tool 26 is further pressed to press the semiconductor chip 16 to a predetermined pressure.

Then, the ultrasonic oscillation output / time setting circuit 3
When 0, the ultrasonic oscillation circuit 32 is operated to ultrasonically vibrate the ultrasonic transducer 28 (S20). Thereby, the vibration of the ultrasonic transducer 28 is transmitted to the semiconductor chip 16, the semiconductor chip 16 vibrates in the horizontal direction (the direction of the arrow in FIG. 4), and the bump 18 and the pad 11 are welded and bonded.

In the process of bonding by ultrasonically oscillating the ultrasonic vibrator 28, when a predetermined time elapses immediately before the completion of the predetermined bonding, the vibration waveform of the semiconductor chip 16 is detected and monitored ( S22). The monitored vibration waveform is sent from the sensor 52 to the A / D conversion circuit 56 as an analog signal, and the digital vibration waveform output from the A / D conversion circuit 56 is further sent to the comparison circuit 58. On the other hand, the optimum digital vibration waveform output from the optimum vibration waveform setting circuit 54 is also sent to the comparison circuit 58, where the comparison circuit 58 compares the digital vibration waveform with the optimum digital vibration waveform, and outputs the result. This output is input to the display device 60 to display the digital vibration waveform and the optimal digital vibration waveform. If the difference between the digital vibration waveform and the optimal digital vibration waveform is within a preset allowable value, the bonding state is normal. On the other hand, if it exceeds the allowable value, it is determined that the bonding state is abnormal (S24).

When it is determined that the bonding state is normal, the bonding is terminated when a predetermined time has elapsed until the completion of the bonding, and the semiconductor device as a product is carried out of the flip chip bonding apparatus 50 and transferred to the product yard. (S26). Then, the new wiring board 12 is placed on the stage 14 (S16),
The bonding operation is repeated (S16 to S24).

On the other hand, if the bonding state is determined to be abnormal, the abnormal state is recorded and an alarm is issued (S
28). The output signal of the comparison circuit 58 is
The setting time of the optimum vibration waveform output / time setting circuit 54 is changed to a predetermined value, for example, twice the normal bonding time or the like, by a control signal from the control unit 62 (S29). The bonding operation is continued. When the extended bonding time elapses, the bonding is terminated, and the semiconductor device is carried out to the work-in-process yard for quality judgment (S30), and the quality of the bonding of the semiconductor device is separately tested and evaluated, and is classified into a good product and a defective product. Next, the control unit 6 receiving the signal from the comparison circuit 58
By 2, the control power supply is turned off, and all devices including the transport system are stopped (S32). Prior to the next bonding operation, the abnormal recording of the bonding state is analyzed, and the vibration output and time are changed to appropriate values (S3).
4) The control power is turned on (S14), and the next bonding operation is performed (S16 to S24).

In the above operation flow and the configuration of the corresponding device, it is most preferable to execute all the steps, but the present invention is not limited to this. For example, after the abnormal state is recorded and the alarm is issued without extending the bonding time (S28), after the normal bonding time elapses, the semiconductor device having the bonding failure is carried out to a defective (off-product) yard ( S30) The configuration may be adopted. In addition, even if the apparatus does not shift to the step of changing the vibration output / time to an appropriate value (S34) after all the apparatuses are stopped (S32) after abnormal operation, for example, the apparatus is inspected. As a result, if the cause of the abnormality is determined and the cause of the abnormality can be removed, there is an effect that a situation in which defective products are continuously generated can be avoided.

According to the flip chip bonding apparatus 50 and the method according to the fourth example of the present embodiment, the vibration waveform of the semiconductor chip 16 is detected and monitored by the sensor 52 and compared with the optimum vibration waveform.
The quality of the bonding state is determined. Also, by displaying the vibration waveform and the optimal vibration waveform on a display device,
More accurate judgment can be made on the bonding state. In addition, when a bonding failure occurs, an alarm is issued, and all the devices are temporarily stopped, so that a situation in which defective products are continuously generated can be avoided. Further, prior to the next bonding operation, the abnormal recording of the bonding state is analyzed, and the vibration output and time are set and changed to appropriate values, so that appropriate manufacturing quality control can be realized.

Next, a flip chip bonding apparatus 64 according to a fifth example of the present embodiment will be described with reference to FIG. Flip chip bonding device 64
Is composed of substantially the same components as the flip-chip bonding apparatus 50 of the fourth example of the present embodiment, except for the following points.

That is, the monitoring of the vibration waveform of the semiconductor chip 16 by the sensor 52 is performed at predetermined monitoring (sampling) intervals after the start of the bonding operation. The difference signal output from the comparison circuit 58 is sequentially input to the ultrasonic oscillation output / time setting circuit 30, and the ultrasonic oscillation output / time set value is changed by a preset amount according to the difference signal level. Is changed, and the bonding operation is feedback-controlled. In this case, the optimum vibration waveform to be compared is the fourth vibration waveform of the present embodiment.
7 is a vibration waveform when the bonding state immediately before the end of bonding is good.

In this case, the display device 60 of the fourth example of the present embodiment may be provided side by side or may not be provided. Further, similarly to the fourth example of the present embodiment, a signal line for inputting a signal from the comparison circuit 58 to the control unit 62 may be provided. According to the flip chip bonding apparatus 64 and the method configured as described above, the bonding operation is feedback-controlled, so that the occurrence of defective products can be avoided as much as possible. In this case, for example, if the vibration waveform greatly deviates from the optimum waveform even when the ultrasonic oscillation time is changed to several times the normal case, unexpected control errors or abnormal bump formation conditions may occur. Is considered, and continuing the bonding work is inconvenient for safety and is not efficient, so for example,
When a time three times as long as the normal bonding time has elapsed, the sequence for terminating the bonding of the product and shifting to the next bonding operation is set (not shown).
However, if the cause of the abnormality is not specific to the product but due to the device, there is a possibility that more defective products will occur. In this case, all devices are stopped without shifting to the next bonding operation. When the system is configured as
It is preferable because appropriate post-treatment can be taken.

Finally, the change in the vibration waveform of the semiconductor chip during the progress of good bonding, the optimum vibration waveform immediately before the end of bonding, and the vibration waveform in the state of poor bonding will be described with reference to FIG.
Consider below. First, the change in the vibration waveform during the progress of bonding will be discussed. In the initial stage of bonding, no welding phenomenon occurs, and thus the semiconductor chip and the ultrasonic vibrator vibrate integrally, so that the reflected wave from the semiconductor chip has a sine wave similar to that of the ultrasonic vibrator. (See FIG. 7A).

As the bonding progresses, the bump and the pad are welded to each other. At the time when the amplitude is maximum, that is, at the time when the horizontal movement is folded, a phenomenon occurs in which the joint is partially cut off. For this reason,
A delay occurs in the vibration of the vibrating semiconductor chip, and the vibration waveform approaches a triangular wave (see FIG. 7B), and substantially becomes a triangular wave at the stage where bonding is successfully completed or immediately before the completion (FIG. 7). (See (c).)

The substantially triangular wave in FIG. 7C corresponds to the optimum vibration waveform described in each of the above embodiments. Next, a vibration waveform in a state where bonding is in a poor state will be examined. First, considering the cause of the bonding failure, firstly, it is conceivable that a slip may occur between the bonding tool and the semiconductor chip. At this time, the bonding tool is contaminated and foreign matter is present between the bonding tool and the semiconductor chip. When slippage occurs, the slip becomes remarkable, and vibration is not reliably transmitted to the bumps. Second, a similar phenomenon occurs when, for example, the tightening of the ultrasonic vibrator and the semiconductor chip is loose.

When such a phenomenon occurs, the amplitude of the vibration waveform becomes smaller than the optimum vibration waveform in any case, and becomes zero in an extreme case (not shown). The quality of the bonding state is determined by monitoring the vibration waveforms different for each of the bonding states during the bonding operation and making a comparison.

[0051]

According to the semiconductor chip bonding method according to the present invention, there is provided a semiconductor chip bonding method for connecting a semiconductor chip to a member on which a wiring pattern is formed by using ultrasonic waves. According to the apparatus used in such a semiconductor chip bonding method, to measure the vibration waveform of the semiconductor chip and grasp the bonding state from the measurement result, the ultrasonic oscillation output and time setting for ultrasonically oscillating the semiconductor chip are set. Circuit, an ultrasonic oscillation mechanism composed of an ultrasonic oscillation circuit and an ultrasonic transducer, and a sensor for measuring a vibration waveform of a semiconductor chip that is ultrasonically vibrated, so that a vibration state of the semiconductor chip is monitored. To achieve good manufacturing quality control in the semiconductor device manufacturing process by taking appropriate measures It can be.

Further, in the semiconductor chip bonding method and apparatus according to the present invention, instead of the semiconductor chip,
When the member on which the wiring pattern is formed is ultrasonically vibrated and the vibration waveform of the member on which the wiring pattern is formed is measured, the effect of the present invention is suitable even when it is not always preferable to apply ultrasonic vibration to the semiconductor chip. Can be played.

According to the semiconductor chip bonding method of the present invention, the optimum vibration waveform corresponding to the optimum bonding state is preset in order to utilize the information on the vibration state monitored by the sensor as described above. , To compare the optimal vibration waveform with the vibration waveform,
As an apparatus therefor, an ultrasonic vibration mechanism includes an A / D conversion circuit to which an analog vibration waveform obtained by a sensor is input, an optimal digital waveform setting circuit for presetting an optimal digital vibration waveform corresponding to an optimal bonding state. ,
A comparison circuit that compares the digital vibration waveform output from the A / D conversion circuit with the optimal digital vibration waveform is further provided, so that the digital vibration waveform and the optimal digital vibration waveform are compared to more accurately determine the bonding state. And make appropriate decisions.

Further, in this case, according to the semiconductor chip bonding method of the present invention, the optimum vibration waveform and the vibration waveform are compared and displayed on the display device, and when the comparison value deviates from a preset reference. In order to display abnormalities, and as a device therefor, the ultrasonic vibration mechanism,
In addition to displaying a signal output from the comparison circuit, the display device further includes a display device that displays an abnormality when the value deviates from a predetermined reference. Therefore, the display of the display device enables more accurate determination of the bonding state. .

In this case, according to the semiconductor chip bonding method according to the present invention, the operation of the semiconductor chip bonding apparatus including the ultrasonic vibration mechanism is further stopped for stopping the semiconductor chip bonding apparatus. A control unit for controlling the stop is further provided, and a signal indicating an abnormality of the display device is input to the control unit to stop the semiconductor chip bonding apparatus, thereby avoiding a continuous occurrence of defective products with incomplete bonding. In addition, it is possible to perform an appropriate abnormality treatment while the apparatus is stopped.

In this case, according to the semiconductor chip bonding method of the present invention, the vibration waveform is feedback-controlled based on the comparison result between the optimum vibration waveform and the vibration waveform. Since the signal output from the comparison circuit is fed back to the ultrasonic oscillation output / time setting circuit and the oscillation waveform is feedback-controlled, the bonding state is always maintained properly, and the occurrence of defective bonding products occurs. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a flip chip bonding apparatus according to a first example of the present embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a flip chip bonding apparatus according to a second example of the present embodiment.

FIG. 3 is a diagram showing a schematic configuration of a flip chip bonding apparatus according to a third example of the present embodiment.

FIG. 4 is a diagram showing a schematic configuration of a flip chip bonding apparatus according to a fourth example of the present embodiment.

FIG. 5 is a flowchart illustrating a flip-chip bonding method according to a fourth example of the present embodiment.

FIG. 6 is a diagram showing a schematic configuration of a flip chip bonding apparatus according to a fifth example of the present embodiment.

FIG. 7 is a diagram for explaining a relationship between a bonding state and a vibration waveform.

[Explanation of symbols]

10, 34, 42, 50, 64 Flip chip bonding apparatus 12 Wiring board 16 Semiconductor chip 20 Bonding unit 22, 38, 46, 52 Sensor 24 Bonding head 26 Bonding tool 28 Ultrasonic transducer 30 Ultrasonic oscillation output / time setting circuit Reference Signs List 32 ultrasonic oscillation circuit 40 piezoelectric element 44 semiconductor chip contact member 54 optimal vibration waveform setting circuit 56 A / D conversion circuit 58 comparison circuit 60 display device 62 control unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norio Uinuma 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Tohru Okada 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Limited F term (reference) 5F044 KK01 LL00 PP15

Claims (12)

[Claims] 1. A semiconductor chip bonding method for connecting a semiconductor chip to a member on which a wiring pattern is formed by using ultrasonic waves, comprising: measuring a vibration waveform of the semiconductor chip which is ultrasonically vibrated;
A bonding method for a semiconductor chip, wherein a bonding state is grasped from the measurement result. 2. A semiconductor chip bonding method for connecting a semiconductor chip to a member on which a wiring pattern is formed by using ultrasonic waves, wherein a vibration waveform of the member which is ultrasonically vibrated is measured, and from the measurement result, A semiconductor chip bonding method characterized by grasping a bonding state. 3. The semiconductor chip bonding method according to claim 1, wherein an optimum vibration waveform corresponding to an optimum bonding state is set in advance, and the optimum vibration waveform is compared with the vibration waveform. 4. The apparatus according to claim 3, wherein said optimum vibration waveform and said vibration waveform are compared and displayed on a display device, and an abnormality is displayed when the comparison value deviates from a preset reference. Semiconductor chip bonding method. 5. The semiconductor chip bonding method according to claim 4, further comprising stopping the semiconductor chip bonding apparatus. 6. The semiconductor chip bonding method according to claim 3, wherein a feedback control of the vibration waveform is performed based on a comparison result between the optimum vibration waveform and the vibration waveform. 7. A semiconductor chip bonding apparatus for connecting a semiconductor chip to a member having a wiring pattern formed thereon using ultrasonic waves, comprising: an ultrasonic oscillation output / time setting circuit for ultrasonically vibrating the semiconductor chip; A semiconductor chip bonding apparatus, comprising: an ultrasonic vibration mechanism including an ultrasonic oscillation circuit and an ultrasonic vibrator; and a sensor for measuring a vibration waveform of the semiconductor chip which is ultrasonically vibrated. 8. A semiconductor chip bonding apparatus for connecting a semiconductor chip to a member on which a wiring pattern is formed using an ultrasonic wave, comprising: an ultrasonic oscillation output / time setting circuit for ultrasonically vibrating the member; A semiconductor chip bonding apparatus, comprising: an ultrasonic vibration mechanism including an oscillation circuit and an ultrasonic vibrator; and a sensor for measuring a vibration waveform of the member that is ultrasonically vibrated. 9. The ultrasonic vibration mechanism includes an A / D conversion circuit to which an analog vibration waveform obtained by the sensor is input, and an optimal digital waveform setting for presetting an optimal digital vibration waveform corresponding to an optimal bonding state. 9. The semiconductor chip bonding apparatus according to claim 7, further comprising: a circuit; and a comparison circuit that compares the digital vibration waveform output from the A / D conversion circuit with the optimal digital vibration waveform. . 10. The ultrasonic vibration mechanism further comprises a display device that displays a signal output from the comparison circuit and displays an abnormality when a comparison value deviates from a preset reference. 10. The semiconductor chip bonding apparatus according to claim 9, wherein: 11. A semiconductor chip bonding apparatus further comprising a control unit for controlling operation / stop of the semiconductor chip bonding apparatus including the ultrasonic vibration mechanism, wherein a signal indicating an abnormality of the display device is input to the control unit. 11. The semiconductor chip bonding apparatus according to claim 10, wherein the semiconductor chip bonding apparatus is configured to stop. 12. The semiconductor chip according to claim 9, wherein a signal output from said comparison circuit is fed back to said ultrasonic oscillation output / time setting circuit to perform feedback control of an oscillation waveform. Bonding equipment.