JPH1074787A - Method and device for wire bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide the optimum bonding condition of a wire bonding device by using the detected result of the sticking state between electronic components mounted on a substrate and the substrate after the bonding device detects the sticking state. SOLUTION: A wire bonding device is provided with a means which detects the sticking state of an adhesive S9 as to detect the sticking state of an electronic component 13 mounted on a substrate 11 to the substrate 11. Based on the detected result of the sticking state, the optimum wire bonding condition of the bonding device is decided and wire bonding is performed by controlling a bonding tool controller by feeding back the detected result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding method and a bonding apparatus for bonding leads to bonding terminals of electronic parts and semiconductor elements and pads.

[0002]

2. Description of the Related Art Conventionally, when a gold wire, a copper wire, or the like is connected to a bonding terminal, a pad, and a lead frame of an electronic component, a semiconductor element, etc., soldering (including a reflow method), ultrasonic bonding, thermocompression bonding, resistance, Bonding means such as bonding is used, and in particular, an ultrasonic bonding method, which is one method of ultrasonic bonding, is often used. It is important to ensure the bonding quality at the junction between the lead wire and the bonding terminal, the pad, and the lead frame, and various control and inspection methods for bonding conditions have been studied.

[0003] First, as a method of inspecting the quality of a bonded portion before bonding, for example, Japanese Patent Application Laid-Open
As in -160229, the quality of the bonding condition of the bonding surface such as scratches on the surface to be bonded such as bonding terminals, pads and lead frames, minute defects such as pinholes, surface roughness, oxide film, material change, etc. There is a method of making a judgment and feeding back this result to the bonding apparatus.

[0004] Various methods have been proposed for determining the quality of bonding during bonding. For example, JP-A-61-237438, JP-A-61-237438
JP-A-237440 and JP-A-62-76731, a method of detecting the waveform and current intensity of a high-frequency current from an ultrasonic oscillator to judge the quality of bonding.
There is a method of detecting the bonding state by measuring the vibration of a tool during bonding by an ultrasonic monitor as disclosed in Japanese Patent No. 2-293731.

Further, after bonding, there are a pull test for checking the bonding strength by pulling the bonded wire by a tension gauge, and a method for estimating the bonding strength from the wire deformation of the bonding portion.

[0006]

SUMMARY OF THE INVENTION Among the above prior arts,
Detecting the bonding state during or after work is effective for determining the quality of bonding.
The yield of finished products cannot be directly improved. Further, even if the inspection is performed before the bonding operation as in Japanese Patent Application Laid-Open No. 5-160229, it is only necessary to judge the quality of the bonding of the wire to the surface to be bonded. Is not taken into account.

In actual bonding, the bonding strength is not determined only by the state of the bonding surface, but is determined by various other factors. In particular, in wire bonding, the electronic components to be bonded are mounted on a substrate or the like with an adhesive before bonding, but the bonding state is naturally different for each substrate and electronic component. It is desirable to detect and bond under the bonding conditions suitable for the detection in order to perform a reliable bonding operation.

However, actually, for example, when the terminals of the electronic component are wire-bonded to the wiring on the substrate by an ultrasonic wire bonding apparatus on a substrate on which the electronic component is fixed with an adhesive, the wire bonding conditions, such as the pressing force of the bonding tool, Set the ultrasonic output, vibration time, etc. to the values empirically determined beforehand, perform wire bonding, observe the bonding state after the work is completed, change the conditions if bonding is insufficient Then, the next work is wire-bonded.

FIG. 1 shows a state of a substrate and electronic components before wire bonding. As shown here, the substrate 11 is fixed by a clamp means (not shown) provided on a sample stage (not shown), and the electronic component 13 (for example, silicon) is mounted on the substrate 11 (for example, resin, ceramic, or the like). (Metal or the like) with an adhesive 12. The adhesive 12 is applied to the substrate 11
Silicone adhesive or the like having elasticity to absorb the difference in thermal expansion between the electronic component 13 and the electronic component 13 is often used. In the ultrasonic wire bonding method, the bonding tool 6 is ultrasonically vibrated so that the bonding wire 9 and the electronic component 13 are relatively moved, and the bonding wire 9 and the electronic component 1 are moved.
The oxide film on the bonding surface of the bonding pad 15 provided on 3 is removed, and both are bonded. Thereafter, the bonding tool 6 is moved above the wiring pattern 14 on the substrate 11, and the bonding wire 9 is bonded to the wiring pattern 14 by the same method.

However, if the rigidity of the adhesive 12 does not reach an appropriate level due to poor curing of the adhesive 12, mixing of air, variation in the thickness of the adhesive, or the like, the electronic component 13 on the adhesive 12 is defective. Due to the wobble or similar defect, the resonance point of the vibration of the electronic component 13 and the adhesive 12 changes, and the natural frequency of the electronic component (the electronic component 13 and the adhesive 12) becomes close to the vibration frequency of the ultrasonic wave. When the electronic component 13 moves with the bonding tool 6 due to resonance,
Sufficient relative movement between the bonding wire 9 and the bonding pad 15 is not possible, resulting in poor bonding.

The difference in the rigidity of the adhesive 12 that causes such a bonding failure depends on each work.
By observing the bonding state with a microscope or the like after the conventional wire bonding and changing the next bonding condition if necessary, it is impossible to obtain the optimum wire bonding conditions according to the change in the rigidity of each adhesive 12. Met.

An object of the present invention is to inspect the bonding state between a mounting component to be bonded and a substrate before bonding so that reliable bonding is achieved for each bonding.
It is an object of the present invention to provide a bonding method and a bonding apparatus which obtain a bonding condition corresponding to each bonding state and feed it back to the bonding, thereby making it possible to manufacture a product of high quality, high reliability and high yield. .

[0013]

According to a first aspect of the present invention, there is provided a wire bonding method and apparatus for connecting a wire to an electronic component mounted on a substrate. In wire bonding for bonding by vibrating relative to a component, the bonding state of the electronic component mounted on a substrate is detected, and based on the detection result, the bonding strength between the electronic component and the wire is secured to a predetermined strength or more. A vibration condition is obtained, and the relative vibration is controlled based on the relative vibration condition.

In the wire bonding method and apparatus according to the present invention, the bonding state between the mounted electronic component and the substrate is detected before performing the wire bonding between the mounted electronic component and the substrate, and the result is fed back to the wire bonding conditions. I do. Therefore, since wire bonding can be performed in accordance with the bonding state of each electronic component, a highly reliable bonding result can be obtained.

According to a second aspect of the present invention, there is provided a wire bonding method and apparatus according to the first or fifth aspect.
The method is characterized in that the rigidity of an adhesive bonding the substrate and the electronic component is detected as the bonding state between the substrate and the electronic component.

In this wire bonding method and apparatus, attention is paid to the adhesive stiffness of the bonding portion as one of the bonding states between the electronic component and the substrate, the detection is performed, and the result is used to determine bonding conditions. Estimating the effect of the electronic components (electronic components and adhesive) on the vibration of the bonding tool from the results of the detection of the adhesive stiffness, determining and executing the optimal bonding conditions that enable reliable bonding, to achieve a more reliable wire Perform bonding.

According to a third aspect of the present invention, there is provided a wire bonding method and apparatus according to the second or sixth aspect.
The adhesive rigidity detected as the bonding state is determined from the amount of strain when the mounted electronic component is pressed against the bonding surface from the side.

In this wire bonding method and apparatus, the electronic component is pressed from the side against the bonding surface, and the rigidity of the adhesive is determined from the amount of strain. The relationship between the natural frequency of the electronic component, the rigidity of the bonded part, the amount of strain, and the output of the vibration wave is known in advance. , The necessary bonding conditions (vibration wave output, frequency, etc.) can be easily obtained.

According to a fourth aspect of the present invention, there is provided a wire bonding method and apparatus according to the first or fifth aspect.
The frequency and acceleration of the electronic component at the time of wire bonding are measured, and the bonding state between the substrate and the electronic component is determined from the result.

In this wire bonding method and apparatus, the frequency and acceleration of the electronic component at the time of wire bonding are measured, and the bonding state between the substrate and the electronic component is determined from the measurement result. Since the bonding state is determined from the vibration state of the electronic component generated during wire bonding, there is no need to externally pressurize and vibrate the electronic component, and a special device or the like necessary for it is not required.

[0021]

Embodiments of the present invention will be described with reference to the drawings.

[0022]

First Embodiment FIG. 1 shows a state in which an electronic component 13 is mounted on a substrate 11. Electronic component 1 on substrate 11
3 is bonded by an elastic adhesive 12 such as silicon. In the present embodiment, an ultrasonic wire bonding method is used as a wire bonding method for causing a wire to relatively vibrate with an electronic component, but a wire bonding method provided with another relative moving means can of course be used. Ultrasonic wire bonding to the electronic component 13 is performed by pressing and vibrating the bonding wire 9 with the bonding tool 6. When the bonding pad 15 provided on the electronic component 13 is bonded to the bonding wire 9, the bonding tool 6 is then moved to the substrate 11.
The wiring pattern 14 is moved above and the bonding between the wiring pattern 14 and the bonding wire 9 is similarly performed.

Next, FIG. 2 shows a configuration diagram of an ultrasonic wire bonding apparatus according to a first embodiment of the present invention. FIG.
As shown in FIG. 1, the ultrasonic wire bonding apparatus according to the first embodiment includes a work 10 on which wire bonding is performed.
(Comprising the substrate 11 and the mounted electronic components 13) are mounted on a sample table 4 including an XY stage 2 having a mechanism for moving the sample table in the horizontal direction and a rotary table 3 having a mechanism for mounting and rotating the sample table. It is configured to ride on the top and fixed to the gantry 1. The bonding tool driving device 5 includes:
The bonding tool 6 is attached, and the ultrasonic output, the frequency, the vibration time, the pressing force, and the like of the bonding tool 6 are controlled by a bonding tool control device (not shown). The bonding wire 9 is supplied with a bonding wire by a bonding wire supply device 7, and the wire is clamped. Further, an image pickup device 8 for checking a pattern is provided for checking an image of a wire bonding position, and an adhesive stiffness measuring device 20 for measuring a bonding state between the mounted electronic component 13 and the substrate 11 is provided. Have been.

FIG. 3 shows an embodiment of the mechanism of the adhesive stiffness measuring device 20. The adhesive rigidity measuring device 20 includes a pressing shaft 21,
The driving unit 22 includes a driving unit 22 and a holding unit 23. Pressing shaft 21
Is movable in the axial direction, and the electronic component 13 is pressed by the pressing shaft 21 with a predetermined pressing force P. Thereby, the electronic component 13 is displaced in the pressing direction in accordance with the rigidity of the adhesive 12, and the displacement δ is measured from the moving stroke of the pressing shaft 21.

FIG. 4 shows a detailed structure of the drive section 22 of the adhesive rigidity measuring device 20. The pressure shaft 21 is supported by a bearing portion 229, and is freely movable in the axial direction by a motor 221, a rack 222, and a pinion 223. The movement of the rack 222 is
Four. As the power for moving the pressurizing shaft 21, a mechanism using a pneumatic pressure and a piston in addition to the motor described above can also be used. The axial force of the pressure shaft 21 is measured by a load sensor 225, and the stroke of the pressure shaft 21 is measured by a lever 226 and a stroke sensor 227. The outputs of the load sensor 225 and the stroke sensor 227 are input to the controller 228, and the controller 228
It controls the output of current and voltage to and the like.

Next, the idea of controlling the bonding conditions from the rigidity of the adhesive 12 will be described. First, a shear strength is considered as a value indicating the bonding strength of the bonding wire 9. Normally, as shown in FIG. 5, the shear strength S is measured by pressing the wire bonding portion 33 bonded on the bonding pad 31 from the side with a measuring tool 32 and applying a pressure P when the wire bonding portion 33 is peeled off. FIG. 6 shows an ultrasonic output U and a shear strength S of a normal ultrasonic wire bonding apparatus.
Shows the relationship. Thus, generally, as the ultrasonic output U increases, the shear strength S also increases, and gradually decreases after reaching the peak.

Electronic component 13 and adhesive 12 mounted
The natural frequency f ₀ of the electronic component (hereinafter referred to as an electronic component) is obtained by considering the natural frequency as the vibration of the cantilever. As shown in FIG. 7, as the electronic component mass m, the adhesive longitudinal elastic modulus E, the second moment of area I of the adhesive 12 in the vibration direction of the bonding tool 6, and the adhesive height h, the natural frequency of the electronic component portion f ₀ and the natural angular frequency ω ₀ are obtained. Assuming that the thickness of the electronic component 13 is about 400 [μm] and the thickness of the adhesive is about 10 [μm], the mass of the adhesive 12 can be neglected. .

[0028]

(1) 2πf ₀ = ω ₀ = √ (3E · I / h ³ · m)) 1st formula f ₀ = ω ₀ / (2π) = 1 / (2π) × √ (3E · I / (h ³ · m)) ··· second equation

Here, the displacement δ of the electronic component 13 when the force P is applied to the electronic component 13 is given by the following formulas (3) and (4).

[0030]

## EQU2 ## δ = P · h ³ / (3E · I) Equation 3 P / δ = 3E · I / h ³ Equation 4

Therefore, the fifth equation is obtained from the second and fourth equations.

[0032]

F ₀ = 1 / (2π) × √ (P / (δ · m)) Formula 5

Here, P / δ is considered to be a value indicating the rigidity of the adhesive 12, and f ₀ is proportional to the square of the rigidity P / δ. This relationship is shown in FIG.

If the electronic component 13 moves at the time of bonding, a bonding failure occurs. The movement becomes maximum when the frequency of the bonding tool matches the natural frequency f ₀ of the electronic component. FIG. 9 shows the relationship between the amplitude A of the vibration of the electronic component 13 and the shear strength S of the bonding portion when the frequency f of the vibration applied to the bonding tool is changed. Here, the bonding conditions other than the frequency of the bonding tool 6 are assumed to be the same. Naturally, when the bonding tool 6 is vibrated at the natural frequency f ₀ of the electronic component portion, the electronic component resonates, the amplitude becomes maximum, and at the same time, the bonding strength of the bonding portion, that is, the shear strength S decreases. In order to suppress the decrease in the shear strength S, it is necessary to change other bonding conditions. As an example, a method of changing the ultrasonic output U will be described.

FIG. 10 is a combination of FIG. 8 and FIG. Since the natural frequency f ₀ of the electronic component varies depending on the cured state of the adhesive 12, the degree of air mixing, the thickness of the adhesive, etc., for example, the characteristic of the electronic component when the value of the rigidity P / δ becomes a The frequency becomes b from the P / δ-f ₀ curve, and the fA curves are superimposed so that b becomes the natural frequency from FIG. 9 (the peak of the amplitude is adjusted to the position of b). However, since the bonding is usually performed at a fixed frequency of the control frequency fb, the actual amplitude of the electronic component at this time is the amplitude Ab at the frequency; f = fb.

As shown in FIG. 11, when the value of P / δ is changed and the change of the amplitude value Ab of the electronic part is examined. Here, as shown in FIG. 9, the shear strength S decreases as the electronic component vibrates (increases in amplitude). Therefore, from FIG. 11, the corresponding change in the shear strength S is shown in FIG. Become like The adhesive rigidity P / in FIG.
From the relationship between δ and the shear strength S and the relationship between the shear strength S and the ultrasonic output U in FIG. 6, in order to secure the reference shear strength S ₀ according to the change in each adhesive stiffness P / δ, FIG. so as to satisfy the relationship may control the ultrasound output U _0.
Therefore, the value of the adhesive stiffness P / δ is calculated by
By controlling the ultrasonic output U _{0 so} that the shear strength S is equal to or higher than the reference shear strength S ₀ as shown in FIG. 13, the bonding strength can be improved.

In the above embodiment, the ultrasonic output U ₀
The method for controlling the bonding conditions has been described above. However, for example, a method for controlling the following bonding conditions may be considered.

<Control of Bonding Frequency> When the natural frequency f ₀ is obtained from the adhesive rigidity P / δ measured by the adhesive portion rigidity measuring device 20, the amplitude Ab at the bonding frequency fb is reduced ( By setting the bonding frequency fb to a value apart from the natural frequency f ₀ so that resonance vibration is suppressed), bonding failure due to resonance can be suppressed. (See FIG. 10) In this case, the allowable amplitude Ab for securing the shear strength S to a required value or more is:
What is necessary is just to determine from the relationship between the amplitude A and the shear strength S (FIG. 9).

<Control of Bonding Tool Pressing Force> The bonding tool pressing force Q is the force with which the bonding tool 6 presses the bonding wire 9 in the bonding tool axis direction during bonding. As with the ultrasonic output U, when the pressing force Q of the bonding tool increases, the shear strength S increases, reaching a peak at a certain point,
Then it gradually decreases. FIG. 14 shows an example of the relationship between the shear strength S and the pressure Q of the bonding tool. When the bonding is performed under the adhesive stiffness P / δ measured by the adhesive stiffness measuring device 20 and the shear strength S decreases, the shear strength S becomes equal to or more than the reference shear strength S ₀ based on the relationship in FIG. By controlling the bonding pressure Q as described above, the bonding strength can be improved.

<Control of Ultrasonic Oscillation Time> As with the ultrasonic output U, the ultrasonic oscillation time T increases as the ultrasonic oscillation time T increases, and the shear strength S increases. Decrease gradually. FIG. 15 shows an example of the relationship between the shear strength S and the ultrasonic oscillation time T. Therefore, as in the case of controlling the bonding tool pressing force Q, bonding is performed under the adhesive rigidity P / δ measured by the adhesive rigidity measuring device 20, and the shear strength S decreases. By controlling the ultrasonic oscillation time T so that the shear strength S becomes equal to or greater than the reference shear strength S ₀ based on the relationship 15, it is possible to improve the bonding strength.

The embodiments of controlling the bonding conditions described above may be used alone or in combination depending on the case. In order to ensure the bonding strength, other bonding conditions may be controlled without being limited to the above-described embodiment.

FIG. 16 shows a flowchart of a processing procedure from the work setting to the start of the wire bonding operation according to the embodiment of the present invention. As shown in the flowchart of FIG. 16, first, the work 10 is positioned and set on the sample table 4 (step 301). When the setting is completed, the current input to the control motor 221 for pressing the pressing shaft 21 is increased (step 302), and at the same time, the output of the load sensor 225 is checked (step 30).
3) increasing the current until the value reaches a predetermined value p ₁ (step 304). Predetermined value p ₁ is a value serving as a reference, but may be zero, in which case the pressure application shaft stops pressurization, and motor current supply at the time of contact with the workpiece.

[0043] At step 305, checks the output of the stroke sensor 227 when the load reaches a predetermined value p _1. This is the reference load and position.

After measuring the reference value, the control motor 22
Increasing the current supplied to the 1, in turn, increases the load to a predetermined load value p ₂ in the same control manner as in the step 302 to 308 (step 306-308).

In step 309, the stroke sensor 2 when the current output of the load sensor (predetermined value p ₂ ) is reached
Check the output of 27.

From the difference between the reference value load value p ₁ and the stroke s ₂ after loading the reference strokes s ₁ and p ₂ ,
The displacement amount δ (= s ₂ −) with respect to the pressing force P (= p ₂ −p ₁ )
s ₁ ) is calculated, and a value P / δ indicating the rigidity of the bonded portion is calculated from this (step 310).

From the relationship between P / δ and the bonding condition, a bonding condition is calculated such that the shear strength of the bonding portion becomes a predetermined value or more (step 311). FIG.
3, a method of calculating with a relationship as shown in FIGS. 14 and 15 is one example.

The apparatus is set to the bonding conditions calculated in step 311 (step 312), and the wire bonding operation is started based thereon (step 31).
3).

[0049]

Second Embodiment FIG. 17 shows an object to be wire-bonded used in the second embodiment. The difference from the one used in the first embodiment is that a test for test bonding is formed on an electronic component 13 separately from a bonding pad 15 which needs to be actually connected to a wiring pattern 14 on a substrate by a bonding wire 9. The point is that pads 16 are provided. In the second embodiment, the bonding state of the electronic component 13 is determined from the measurement result of the vibration state of the electronic component 13 by bonding the test pad 16 and the bonding wire 9 with the bonding tool 6.

Next, FIG. 18 shows a configuration diagram of an ultrasonic wire bonding apparatus according to a second embodiment of the present invention. The difference from the ultrasonic wire bonding device used in the first embodiment shown in FIG. 2 is that an electronic component acceleration measuring device 40 is provided instead of the adhesive rigidity measuring device 20.

FIG. 19 shows an embodiment of the mechanism of the electronic component acceleration measuring device 40. The contact measuring section 41 provided in the electronic component acceleration measuring device 40 contacts a part of the electronic component 13 with a predetermined load, and measures the vibration of the electronic component 13 caused by the vibration of the bonding tool 6 with the acceleration sensor 42. .
The contact measuring section 41 is held by a holding lever section 43, and the holding lever section 43 is balanced with a balance weight 46 attached to a balance weight shaft 45 connected to the other end using a lever fulcrum 44 as a support shaft. By adjusting the position of the balance weight 46, the load applied to the electronic component 13 is adjusted.

The vibration state of the electronic component 13 at the time of wire bonding is transmitted to the contact measuring section 41, measured by the acceleration sensor 42, and the output is sent to the controller 48. The controller 48 further inputs the input measurement value to a calculation means (not shown) to calculate the ultrasonic output, the vibration frequency, the vibration time, the pressing force, etc. of the bonding tool 6 and, at the end of the work, the tactile measurement. It also serves to issue a command to move the unit 41 to the control solenoid 47. Here, although a solenoid is used as a means for moving the contact measuring unit 41, the holding lever unit 43, and the like, a modified example using a piston or the like may be considered.

Next, a method of controlling the bonding condition from the vibration (acceleration) of the adhesive 13 will be described. As an expression of the bonding strength of the bonding wire 9, the shear strength is considered as in the first embodiment. When wire bonding is performed under the same bonding conditions, as shown in FIG. 20, as the vibration amplitude A of the electronic component 13 increases, the shear strength S, that is, the bonding strength decreases.

Here, the amplitude of the electronic component 13 at the time of bonding is A, the frequency is f, and the angular frequency is ω.
Assuming that the vibration of No. 3 is a sine vibration, the displacement x, velocity, v, and acceleration α are

[0055]

X = A sin ωt Equation 6 v = Aω cos ωt Equation 7 α = −Aω ² sin ωt Equation 8

Therefore, if the maximum acceleration is αm,

[0057]

Αm = Aω ² A = αm / ω ² = αm / (2πf) ² (9)

Therefore, by measuring the vibration frequency f of the electronic component and the maximum value αm of the vibration acceleration at the time of bonding in the electronic component acceleration measuring device 40, it is possible to know the amplitude A of the electronic component 13 from the relationship of the ninth formula. it can.

As shown in FIG. 6 in the first embodiment, the relationship between the ultrasonic output U and the shear strength S of the ordinary ultrasonic wire bonding apparatus generally indicates that the shearing power increases as the ultrasonic output U increases. The intensity S also increases, and gradually decreases after reaching the peak. Therefore, according to FIGS. 6 and 20, in order to secure the reference shear strength S ₀ according to the change in the amplitude A of each electronic component 13, the ultrasonic output U is adjusted so as to satisfy the relationship of FIG.
_It is better to control ₀ .

[0060] Thus, to measure the maximum value αm of the vibration acceleration and the vibration frequency f of the electronic component at the time of bonding, the reference shear strength ultrasonic output U ₀ shear strength S is as shown in FIG. 21 S
_By controlling to be ₀ or more, the bonding strength can be improved.

FIG. 22 shows a flowchart of a processing procedure from the test work set to the start of the wire bonding operation according to the embodiment of the present invention. As shown in the flowchart of FIG. 21, first, the work 10 is positioned and set on the sample table 4 (step 401). When the setting is completed, the controller 48 sets the control solenoid 4
7 to make the contact measuring section 41 contact the electronic component 13 (steps 402 and 403).

When the contact of the contact measuring section 42 to the electronic component 13 is completed, the bonding operation for the test pad 16 is started (steps 404 and 405). When the bonding operation starts, the acceleration sensor 42 measures the acceleration and the frequency (step 406). The maximum acceleration αm and the frequency f at that time are obtained from the measured acceleration and the frequency,
Based on this, the amplitude A is calculated (step 407), and the bonding condition such that the shear strength becomes a predetermined value or more is calculated from the relationship between the amplitude A and the bonding condition (step 408). One example is a method of calculating the control ultrasonic output based on the relationship shown in FIG.

The apparatus is set to the bonding conditions calculated in step 408 (step 409), and the control solenoid 47 tests the contact measuring section based on a command from the controller 48 to move the contact measuring section 41 upon completion of the measuring operation. Release from the pad 16 (Step 410,
411). Subsequently, the actual wire bonding operation is started (step 412).

Although not specifically exemplified, the present invention can be carried out in various modified and improved forms based on the knowledge of those skilled in the art without departing from the scope of the claims.

[0065]

According to the wire bonding apparatus according to the present invention, a detecting means for detecting an adhesion state between a substrate and a mounted electronic component, an optimum wire bonding condition is determined by using the result, and each wire bonding condition is determined. Since the bonding control device is equipped with a control unit that issues a feedback command, it is possible to perform bonding in accordance with the bonding state of individual electronic components, making it possible to manufacture high-quality, high-reliability, and high-yield products. become.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a relationship between a substrate and a mounted electronic component before wire bonding.

FIG. 2 is a configuration diagram of a wire bonding apparatus according to a first embodiment of the present invention.

FIG. 3 is a configuration diagram of an adhesive stiffness measuring device according to the first embodiment of the present invention.

FIG. 4 is a detailed view of an adhesive stiffness measurement control unit according to the first embodiment of the present invention.

FIG. 5 is a view showing a method for measuring a shear strength.

FIG. 6 is a diagram illustrating a relationship between a shear strength and an ultrasonic output of a bonding apparatus.

FIG. 7 is a diagram illustrating a relationship between a pressing force and a movement amount in an adhesive portion.

FIG. 8 is a diagram illustrating a relationship between a natural frequency of an electronic component and rigidity of an adhesive;

FIG. 9 is a diagram illustrating a relationship between a bonding frequency, an amplitude of an electronic component portion, and a bonding portion shear strength;

FIG. 10 is a diagram for explaining a method of superposing FIGS. 8 and 9 and obtaining a stiffness from the amplitude of an actual electronic component part.

FIG. 11 is a diagram illustrating a relationship between amplitude of an electronic component and rigidity of an adhesive;

FIG. 12 is a diagram illustrating a relationship between shear strength and rigidity of a bonding portion.

FIG. 13 is a diagram showing the relationship between the required ultrasonic output of the wire bonding apparatus and the rigidity of the adhesive.

FIG. 14 is a diagram illustrating a relationship between a shear strength of a bonding portion and a pressing force of a bonding tool;

FIG. 15 is a diagram illustrating a relationship between a shear strength of a bonding portion and an ultrasonic frequency of a bonding tool.

FIG. 16 is a flowchart showing a series of flows according to the first embodiment of the present invention.

FIG. 17 is a schematic view of an electronic component used in the second embodiment of the present invention.

FIG. 18 is a configuration diagram of a wire bonding apparatus according to a second embodiment of the present invention.

FIG. 19 is a configuration diagram of an electronic component acceleration measuring device according to a second embodiment of the present invention.

FIG. 20 is a diagram illustrating a relationship between amplitude of an electronic component and shear strength of a bonding portion;

FIG. 21 is a diagram illustrating a relationship between an amplitude of an electronic component and an ultrasonic output of a bonding tool.

FIG. 22 is a flowchart showing a series of flows according to the second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 4 Sample table 5 Bonding tool driving device 6 Bonding tool 8 Pattern recognition imaging device 9 Bonding wire 10 Work 11 Board 12 Adhesive 13 Electronic component 14 Wiring pattern 15 Bonding pad 16 Test pad 20 Adhesive rigidity measuring device 21 Adhesive rigidity measurement Pressing shaft 22 Adhesive stiffness measuring drive unit 23 Adhesive stiffness measuring device holding unit 221 Motor 225 Load sensor 226 Lever 227 Stroke sensor 228 Controller 229 Bearing 31 Bonding pad 32 Measurement tool 33 Wire joint 40 Electronic component acceleration measuring device 41 contact measuring unit 42 acceleration sensor 43 holding lever unit 44 lever fulcrum 45 balance weight shaft 46 balance weight 47 control solenoid 48 controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/66 H01L 21/66 R

Claims (8)

[Claims] In a wire bonding method for bonding a wire to an electronic component mounted on a substrate by relatively vibrating the wire with the electronic component, a bonding state of the electronic component mounted on the substrate is detected, and the detection result is obtained. A wire bonding method comprising: determining a relative vibration condition that ensures a bonding strength between an electronic component and a wire equal to or higher than a predetermined strength, and controlling the relative vibration based on the relative vibration condition. 2. The wire bonding method according to claim 1, wherein the rigidity of an adhesive bonding the substrate and the electronic component is detected as a bonding state between the substrate and the electronic component. 3. The wire according to claim 2, wherein the rigidity of the adhesive detected as the bonding state is determined from the amount of strain when the mounted electronic component is pressed from the side against the bonding surface. Bonding method. 4. The wire bonding method according to claim 1, wherein a frequency and an acceleration of the electronic component at the time of wire bonding are measured, and a bonding state between the substrate and the electronic component is determined from the result. 5. A wire bonding apparatus for bonding a wire to an electronic component mounted on a substrate by relatively vibrating the wire with the electronic component, wherein a bonding state detecting means for detecting a bonding state of the electronic component mounted on the substrate. A relative vibration condition determining unit that obtains a relative vibration condition in which the bonding strength between the electronic component and the wire is secured to a predetermined strength or more based on the detection result;
A wire bonding apparatus comprising a control unit for controlling relative vibration based on the relative vibration condition. 6. A wire bonding apparatus according to claim 5, wherein said bonding state detecting means detects the rigidity of an adhesive bonding the substrate and the electronic component. 7. The method according to claim 6, wherein the adhesive stiffness detected by the bonding state detecting means is determined from a strain amount when the mounted electronic component is pressed against the bonding surface from the side. Wire bonding equipment. 8. The wire bonding apparatus according to claim 5, wherein the frequency and acceleration of the electronic component during wire bonding are measured, and the bonding state between the substrate and the electronic component is determined from the result.