JP4043391B2 - Electronic component mounting method and mounting apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting method for bonding an electronic component onto a substrate and a mounting apparatus for the same.
[0002]
[Prior art]
Conventionally, as a method of mounting an electronic component on a substrate, a solder paste made of solder powder and a flux (flux) is transferred onto an electrode of the substrate by a screen printer, and the terminals of the electronic component are soldered by a mounter. After mounting on the electrode of the substrate coated with the paste, heating in a reflow furnace, melting the solder paste, and electrically and mechanically bonding between the terminal of the electronic component and the electrode of the substrate, It is still used for manufacturing electrical and electronic equipment products.
[0003]
This heating mounting method has problems of electrical damage due to the melting material and reduced reliability due to thermal strain because the joints have become finer as electronic devices and semiconductor devices become smaller and more functional. ing.
[0004]
Based on this background, new mounting methods are being studied.
[0005]
For example, there is a mounting method in which the contact area between the protruding electrode and the mounting pad is deformed so as to expand from a point to a surface, and then the sealing resin is cured and bonded (for example, see Patent Document 1).
[0006]
In addition, there is a mounting method in which gold-gold bonding, gold-aluminum bonding, or solder bonding is performed by solid-phase diffusion using ultrasonic vibration or ultrasonic vibration and heating without using a melting material (see, for example, Patent Document 2).
[0007]
Furthermore, there is a mounting method in which bonding surfaces are activated by energy wave irradiation and then bonded at normal temperature (see, for example, Patent Document 3).
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-97816 (page 3-4, FIG. 1)
[0009]
[Patent Document 2]
Japanese Patent Laid-Open No. 10-335373 (page 3-4, FIG. 1)
[0010]
[Patent Document 3]
JP 2001-351892 A (page 3-4, FIG. 1)
[0011]
[Problems to be solved by the invention]
The mounting method developed in place of the conventional general-purpose mounting method using a reflow furnace has the following problems.
[0012]
In the case of the protruding electrode described in Patent Document 1, usually, a bump having a protruding portion at the center called a gold stud bump is applied to the electrode terminal portion of the electronic component one by one by a method applying gold wire bonding technology. Need to be formed. This is a time-consuming method for forming terminals, and is expensive for a semiconductor device for high-speed information processing.
[0013]
Further, as described in the example of Patent Document 1, in order to sufficiently deform the gold stud bump, a load of 30 g per bump is required, and heat treatment at 270 ° C. is performed to cure the resin. Generation of distortion is inevitable.
[0014]
Basically, the mounting method of Patent Document 1 uses the shrinkage stress of the sealing resin as the basis of reliability in the mechanical connection, and thus has a problem of reliability reduction due to stress relaxation of the resin.
[0015]
Furthermore, application to joining of soft solder alloy or the like is impossible because the oxide film on the metal surface cannot be removed.
[0016]
Next, in the mounting of electronic components using ultrasonic vibration described in Patent Document 2, solder bonding is realized without using a melting material. This is a method of solid phase diffusion.
[0017]
However, this method requires heating near or above the melting point of the joining member, and the problem of thermal strain is not solved.
[0018]
Furthermore, miniaturization of the junction terminal part and reduction of the dielectric constant of the semiconductor device make the mechanical strength of the terminal part fragile, so that damage to the terminal part due to ultrasonic vibration is in danger.
[0019]
Next, the method described in Patent Document 3 removes oxides and impurities by cleaning the bonding metal surface by energy wave irradiation, and activates the bonding metal surface, thereby heating the metal terminal portion without heating. This is based on the technique of diffusion bonding.
[0020]
However, since this method basically does not plastically deform the electrode portion, the terminal surface provided on the electronic component and the terminal surface on the substrate side are smooth and Small variation in height It requires state and its control is extremely difficult.
[0021]
Furthermore, energy wave irradiation requires a high-cost apparatus from the viewpoint of using a vacuum processing technique, and is not versatile.
[0022]
Further, the bonding material is not limited to gold when not heated, and heating is required for bonding with copper. Furthermore, it cannot be applied to soft solder alloys.
[0023]
The present invention has been made in view of these points, and has various problems associated with conventional mounting methods by deformation of protruding electrodes, solid-phase diffusion methods by ultrasonic vibration, and surface activation treatment methods by energy wave irradiation. It is an object of the present invention to provide an electronic component mounting method and a mounting apparatus capable of solving the problem.
[0024]
[Means for Solving the Problems]
The invention described in claim 1 is formed in a protruding shape. An oxide film can be formed on the surface Electronic components with metal terminals on the board Projecting Been formed An oxide film can be formed on the surface When mounting on a metal terminal for bonding, the load is applied by offsetting the terminal position of the electronic component with respect to the terminal position on the board by 40% or more of the terminal diameter. Then, the metal terminals of the electronic component and the substrate are plastically deformed and metal-bonded. Electronic component mounting method for electronic components and substrates Formed in a protruding shape Apply load by offsetting each metal terminal from their center position by 40% or more of the terminal diameter Plastic deformation By each It is possible to make enough plastic deformation to destroy the oxide film on the surface of the metal terminal, and the stress on the terminal surface accompanying the plastic deformation at this time becomes the driving force of solid phase diffusion, and the intermetallic bond is obtained. In addition, by applying a load by offsetting each metal terminal of the electronic component and the substrate, it is possible to cope with variations in height that vary depending on the metal terminal, and the conventional mounting method by deformation of the protruding electrode and fixation by ultrasonic vibration. Various problems that the phase diffusion method and the surface activation treatment method by energy wave irradiation have can be solved.
[0025]
Contract Claim 2 The invention described in claim 1 1 At least one of the electronic component and the metal terminals of the board to be joined by the mounting method of the electronic component described above is at least one of a soft solder alloy and a low-rigidity metal such as tin, lead, indium, and indium alloy. The selected mounting method is a soft solder alloy or a metal terminal made of low-rigidity metal such as tin, lead, indium, or indium alloy, and its surface is easily plastically deformed. Is suitable.
[0026]
Claim 3 The invention described in claim 1 Or 2 The electronic component mounting method described is a mounting method in which a load is applied after the electronic component is positioned with respect to the substrate, and a force that plastically deforms the metal terminal is reliably applied by applying the load after the electronic component is positioned with respect to the substrate. Can do.
[0027]
Claim 4 The invention described in claim 1 to claim 1 3 In the electronic component mounting method according to any one of the above, since the load is applied only in the vertical direction, and the load is applied only in one direction in the vertical direction, the mechanical strength between the metal terminals is deteriorated. And non-contact or poor contact can be prevented.
[0028]
Claim 5 The invention described in claim 1 to claim 1 4 The electronic component mounting method described in any one of the above is a mounting method in which the electronic component is mounted on the substrate in a non-heated state, and the reliability in the thermal strain can be prevented by mounting in the non-heated state.
[0029]
Claim 6 The invention described in claim 1 to claim 1 5 The electronic component mounting method according to any one of the above, wherein the mounting of the electronic component on the substrate is performed in a non-melting material state, and the mounting of the electronic component on the substrate is performed in a non-melting material state. Therefore, electrical damage due to the melt can be prevented.
[0030]
Claim 7 The invention described in claim 1 to claim 1 6 The electronic component mounting method according to any one of the above, wherein the electronic component mounting includes a step of filling an underfill material into the gap between the electronic component and the substrate by capillary action after mounting the electronic component on the substrate. Later, the underfill material is filled in the gap between the electronic component and the substrate by capillary action, so the underfill material is caught between the electronic component and the metal terminal of the substrate by applying the underfill material before mounting the electronic component. Can be prevented, and high bonding reliability can be secured.
[0031]
Claim 8 The invention described in claim 1 to claim 1 7 At least one of the electronic component and the substrate used in the electronic component mounting method described in any of the above is a mounting method selected from at least one of organic materials, ceramic materials, semiconductor materials, and composites thereof Even if at least one of the electronic component and the substrate is an organic material, a ceramic material, a semiconductor material, or a composite thereof, the metal-to-metal bonding by solid phase diffusion between these electronic components and each metal terminal of the substrate can get.
[0032]
Claim 9 The electronic component holding mechanism for holding the electronic component, the substrate holding mechanism for holding the substrate on which the electronic component is mounted, and the projection of the electronic component are formed. An oxide film can be formed on the surface Metal terminal and board Projecting Been formed An oxide film can be formed on the surface Positioning mechanism for positioning metal terminals by offsetting the terminal position of the electronic component with respect to the terminal position on the substrate by 40% or more of the diameter of the metal terminal, and moving the electronic component relative to the substrate only in the vertical direction And applying a load between the metal terminal of the electronic component and the metal terminal of the substrate and controlling the load to connect the metal terminal of the electronic component and the metal terminal of the substrate. Plastically deformed An electronic component mounting apparatus including a load control mechanism for metal bonding, and includes an electronic component holding mechanism, a substrate holding mechanism, and a positioning mechanism. Formed in a protruding shape With each metal terminal positioned and offset by 40% or more of the metal terminal diameter from the center position, the load is controlled by moving the electronic component relative to the board only in the vertical direction. Plastic deformation By each Since it is possible to make enough plastic deformation to destroy the oxide film on the metal terminal surface, the stress on the terminal surface accompanying the plastic deformation at this time becomes the driving force of solid phase diffusion, and the intermetallic bond is obtained, In addition, by applying a load by offsetting each metal terminal of the electronic component and the substrate, it is possible to cope with variations in height that differ depending on the metal terminal, a conventional mounting method by deformation of the protruding electrode, and a solid phase by ultrasonic vibration. Various problems that the diffusion method and the surface activation treatment method by energy wave irradiation have can be solved.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.
[0034]
FIG. 1 shows an electronic component mounting apparatus, in which a substrate holding mechanism 22 for holding a substrate 21 is provided so as to be movable in a plane direction, that is, an XY direction by a positioning mechanism 23 having an XY positioning stage. .
[0035]
An electronic component holding mechanism 25 that holds the electronic component 24 so as to face the substrate 21 is installed below the load control mechanism 26.
[0036]
As shown in FIG. 2A, the positioning mechanism 23 includes a metal terminal 24a formed on the electrode portion of the electronic component 24 and a metal terminal 21a formed on the substrate 21 on which the electronic component 24 is mounted. The terminal position of the electronic component 24 is offset from the terminal position on the terminal 21 by 40% or more of the metal terminal diameter.
[0037]
As shown in FIGS. 2B to 2C, the load control mechanism 26 moves the electronic component 24 relative to the substrate 21 only in the vertical direction and is positioned in the offset state. A load in only the vertical direction is applied between the terminal 24a and the metal terminal 21a of the substrate 21, and the load is controlled to metal-bond the metal terminal 24a of the electronic component 24 and the metal terminal 21a of the substrate 21. is there.
[0038]
At least one of the substrate 21 and the electronic component 24 handled by this mounting apparatus is selected from at least one of an organic material, a ceramic material, a semiconductor material, and a composite thereof.
[0039]
The electronic component 24 includes not only a semiconductor device but also a subassembly substrate on which a circuit is formed.
[0040]
Further, the metal terminal 24a of the electronic component 24 to be metal-bonded and the metal terminal 21a of the substrate 21 are bumps formed in a protruding shape, and at least one of these metal terminals 24a and 21a to be metal-bonded is a soft solder. It is selected from at least one of an alloy and a low-rigidity metal such as tin, lead, indium, and an indium alloy.
[0041]
Next, an electronic component mounting method performed using such an electronic component mounting apparatus will be described.
[0042]
As shown in FIGS. 2A and 2B, when the electronic component 24 having the protruding metal terminals 24a is mounted on the bonding metal terminals 21a formed on the substrate 21. The positioning mechanism 23 of the mounting apparatus positions the terminal position of the electronic component 24 with respect to the terminal position on the substrate 21 by offsetting 40% or more of the terminal diameter.
[0043]
After such positioning of the electronic component 24 with respect to the substrate 21, as shown in FIG. 2C, the electronic component 24 is moved downward by the load control mechanism 26 and in an offset state with respect to the metal terminal 21a of the substrate 21. A load in the vertical direction is applied to the metal terminal 24a of the electronic component 24 in contact therewith. At this time, at least one surface of each of the metal terminals 21a and 24a of the substrate 21 and the electronic component 24, which are positioned by offsetting the terminal position by 40% or more of the terminal diameter, is plastically deformed.
[0044]
That is, in this mounting method, when mounting the electronic component 24 having the metal terminal 24a formed in a protruding shape on the bonding metal terminal 21a formed on the substrate 21, the substrate 21 and the electronic component 24 are In this mounting method, a load is applied so as to plastically deform at least one surface of each of the metal terminals 21a, 24a. However, the load is applied only in the vertical direction after the electronic component 24 is positioned with respect to the substrate 21.
[0045]
At this time, the electronic component 24 is mounted on the substrate 21 in a non-heated state, that is, at room temperature. Further, the electronic component 24 is mounted on the substrate 21 in a non-melt material state in which a flux, that is, a flux is not used.
[0046]
In this way, by applying a load by offsetting the metal terminals 21a, 24a of the substrate 21 and the electronic component 24, the amount of plastic deformation of the metal terminals 21a, 24a increases, so that the metal terminals 21a, 24a It is possible to cope with variations in different heights, and reliable metal bonding between the metal terminals 21a and 24a becomes possible.
[0047]
As shown in FIG. 2D, after the electronic component 24 is mounted on the substrate 21, there is a step of filling the gap between the substrate 21 and the electronic component 24 with the underfill material 31 by capillary action.
[0048]
The filling of the underfill material 31 is performed in the mounting method of the substrate 21 and the electronic component 24 having significantly different thermal expansion coefficients in order to ensure mounting reliability against thermal strain caused by mismatch of the thermal expansion coefficients. The underfill material 31 is injected and cured between the electronic component 24 and the electronic component 24 to reinforce the mechanical strength.
[0049]
The underfill material 31 is preferably a thermosetting resin, that is, a thermosetting epoxy material, but may be an ultraviolet curable material.
[0050]
When the electronic component (semiconductor device) 24 is mounted on the resin substrate 21 by flip-chip bonding, the epoxy resin, which is the main material of the underfill material 31, has a low elastic modulus and a large coefficient of thermal expansion. Therefore, it is desirable to add a filler such as silica and adjust the physical property value to match that of the semiconductor.
[0051]
Also, the supply method of the underfill material 31 is divided into first-in and last-in, for example, in the case of a small semiconductor device of about 5 mm square, a mechanical stress due to thermal strain is small, and a device with a small number of terminals using gold bumps In mounting, an underfill material that does not include a filler is applied in advance on the substrate. However, in the case of a semiconductor device of 10 mm or more, since mechanical stress due to thermal strain is large, a filler is included. An underfill material 31 is used.
[0052]
In this case, in the first-in method, the filler in the underfill material 31 bites into the metal joint between the metal terminals 21a and 24a, and the joining reliability is lowered. Therefore, after mounting the electronic component 24 on the substrate 21, A post-insertion method in which an underfill material 31 is injected into the gap is desirable. The underfill material 31 flows between the electronic component 24 and the substrate 21 by a capillary phenomenon.
[0053]
Then, after the underfill material 31 is supplied between the electronic component 24 and the substrate 21, the underfill material 31 is heated to about 150 ° C. and cured to firmly bond the electronic component 24 and the substrate 21 to the machine. Provides effective reinforcement effect.
[0054]
In this way, by applying a load by offsetting the metal terminals 21a, 24a of the substrate 21 and the electronic component 24 by 40% or more of the terminal diameter from their center positions, the surface of these metal terminals 21a, 24a is oxidized. It is possible to cause sufficient plastic deformation to break the film, and the stress on the terminal surface accompanying the plastic deformation at this time becomes a driving force for solid phase diffusion, and an intermetallic bond is obtained. By applying a load by offsetting the metal terminals 21a, 24a of the electronic component 24, it is possible to cope with variations in height that differ depending on the metal terminals 21a, 24a. Various problems that the solid phase diffusion method using vibration and the surface activation processing method using energy wave irradiation have can be solved.
[0055]
For example, there are problems with strong activity, high costs for protecting the global environment, points that require a cleaning process, poor production efficiency, difficult control, and high cost equipment It is possible to solve the problems that are not universal and the bonding material is limited to gold.
[0056]
Further, by applying a load so as to plastically deform at least one surface of each of the metal terminals 21a, 24a of the substrate 21 and the electronic component 24, the oxide films on the surfaces of these metal terminals 21a, 24a are destroyed, The stress on the terminal surface due to plastic deformation becomes the driving force for solid phase diffusion, and the metal-to-metal bond is obtained, so the conventional mounting method by deformation of protruding electrodes, solid phase diffusion method by ultrasonic vibration, surface activity by energy wave irradiation It is possible to solve various problems that the processing method has.
[0057]
The metal terminals 21a, 24a made of soft solder alloy or low-rigidity metal such as tin, lead, indium and indium alloy are easy to plastically deform on the surface and are suitable for destroying the oxide film on the surface. .
[0058]
In addition, by applying a load after positioning the electronic component 24 with respect to the substrate 21, a force for plastic deformation of the metal terminals 21a and 24a can be reliably applied.
[0059]
Further, since the load is applied only in one direction in the vertical direction, it is possible to prevent deterioration of the mechanical strength between the metal terminals 21a and 24a, non-contact or poor contact.
[0060]
In addition, reliability reduction due to thermal strain can be prevented by mounting in an unheated state.
[0061]
In addition, since the electronic component 24 is mounted on the substrate 21 in a non-melt material state that does not use a flux, that is, a flux, electrical damage due to the melt can be prevented.
[0062]
In addition, since the underfill material 31 is filled in the gap between the substrate 21 and the electronic component 24 by capillary action after the electronic component 24 is mounted, the substrate 21 and the electronic device can be obtained by applying the underfill material before the electronic component 24 is mounted. The underfill material 31 can be prevented from biting between the metal terminals 21a and 24a of the component 24, and high joint reliability can be secured.
[0063]
Further, even if at least one of the substrate 21 and the electronic component 24 is an organic material, a ceramic material, a semiconductor material, or a composite thereof, the metal terminals 21a and 24a between the substrate 21 and the electronic component 24 Intermetallic bonds are obtained by solid phase diffusion.
[0064]
Further, the substrate holding mechanism 22, the positioning mechanism 23, and the electronic component holding mechanism 25 are used to offset the metal terminals 21a, 24a of the substrate 21 and the electronic component 24 from their central positions by 40% or more of the metal terminal diameter. The plastic deformation sufficient to destroy the oxide film on the surface of the metal terminal by applying the load by moving the electronic component 24 relative to the substrate 21 only in the vertical direction by the load control mechanism 26 in the positioned state. Since the stress on the terminal surface due to plastic deformation at this time becomes a driving force for solid phase diffusion and an intermetallic bond is obtained, each of the metal terminals 21a, 24a of the substrate 21 and the electronic component 24 is also obtained. By applying a load with offset, it is possible to cope with variations in height that differ depending on each metal terminal 21a, 24a, mounting method by deformation of conventional protruding electrode, solid phase by ultrasonic vibration METHOD dispersion, various problems surface activation treatment methods have not have by energy wave irradiation can be solved.
[0065]
【Example】
Next, in contrast to the electronic component mounting form of the present invention shown in FIG. 2, FIG. 3 shows a conventional electronic component mounting form in which the electronic component 12 is placed on the metal terminal 11a for bonding formed on the substrate 11. When the metal terminals 12a are mounted, these metal terminals 11a, 12a are not offset at all. In this case, as shown in the following measured data, the metal terminals 11a, The amount of plastic deformation on the surface of 12a is small.
[0066]
On the other hand, as shown in the following actual measurement data, the electronic component mounting form of the present invention can obtain large plastic deformation even with the same load as compared with the conventional method without an offset amount.
[0067]
The metal terminal 21a on the substrate 21 side used for the actual measurement is a solder bump on the bonding electrode side that has been subjected to fluttering (flattening) treatment with a glass plate, as shown in FIG. 4 (a). In the state where the flatness on the substrate 21 side is ensured, the terminal surface is a flat surface 21b having a certain area. However, as shown in FIG. It is also possible to do.
[0068]
Figure 5 shows 45 kg (per bump) 112.5 This is actual measurement data showing the correlation between the offset amount and the bump plastic deformation amount when the electronic component 24 is mounted on the substrate 21 by the mounting method of the present invention in which the vertical load of g) is applied.
[0069]
At this time, the metal terminal 21a on the substrate 21 side is a soft solder alloy represented by a metal composition of Sn-3.0Ag-0.5Cu, and the metal terminal 24a on the electronic component 24 side is represented by Sn-3.5Ag. It is a soft solder alloy, each of which has a terminal dimension of approximately 100 μm, and a silicon chip having 400 terminals is used as the electronic component 24.
[0070]
From the relationship between the bump plastic deformation amount and the offset amount shown in FIG. 5, it can be seen that the plastic deformation amount is saturated at an offset amount of 50 μm or more.
[0071]
Moreover, FIG. 6 is actual measurement data showing the correlation between the offset amount, the dichroic strength, and the electrical jointability. As for the load condition, a vertical load of 45 × 9.8 N is applied for 5 minutes, and the die shear speed is applied at 300 μm / second.
[0072]
It can be seen from the relationship of the dyshear strength with respect to the offset amount shown in FIG.
[0073]
Furthermore, it can be seen from the relationship of the electrical connection property to the offset amount shown in FIG. 6 that electrical conduction can be obtained with an offset amount of 40 μm or more.
[0074]
Next, FIG. 7 to FIG. 14 are micrographs for comparing the deformation state of the surface of the solder bumps, that is, the metal terminals 21a subjected to the flattening process when the offset amount is changed, and FIG. 7 shows the offset amount of 0 μm. 8 shows a case where the offset amount is 10 μm, FIG. 9 shows a case where the offset amount is 20 μm, FIG. 10 shows a case where the offset amount is 30 μm, and FIG. 11 shows an offset amount. 12 is a case where the offset amount is 50 μm, FIG. 13 is a case where the offset amount is 60 μm, and FIG. 14 is a case where the offset amount is 70 μm.
[0075]
【The invention's effect】
According to the first aspect of the present invention, the electronic component and the substrate Formed in a protruding shape Apply load by offsetting each metal terminal from their center position by 40% or more of the terminal diameter Plastic deformation By each It is possible to make enough plastic deformation to destroy the oxide film on the surface of the metal terminal, and the stress on the terminal surface accompanying the plastic deformation at this time becomes the driving force of solid phase diffusion, and the intermetallic bond is obtained. In addition, by applying a load by offsetting each metal terminal of the electronic component and the substrate, it is possible to cope with variations in height that vary depending on the metal terminal, and the conventional mounting method by deformation of the protruding electrode and fixation by ultrasonic vibration. Various problems that the phase diffusion method and the surface activation treatment method by energy wave irradiation have can be solved.
[0076]
Contract Claim 2 According to the described invention, a soft solder alloy or a metal terminal made of a low-rigidity metal such as tin, lead, indium, or an indium alloy is easily deformable on the surface and is suitable for destroying the oxide film on the surface. ing.
[0077]
Claim 3 According to the described invention, a force for plastic deformation of the metal terminal can be reliably applied by applying a load after positioning the electronic component with respect to the substrate.
[0078]
Claim 4 According to the described invention, since the load is applied only in one direction in the vertical direction, it is possible to prevent deterioration of mechanical strength between the metal terminals, non-contact or poor contact.
[0079]
Claim 5 According to the described invention, a decrease in reliability due to thermal strain can be prevented by mounting in a non-heated state.
[0080]
Claim 6 According to the described invention, since the electronic component is mounted on the substrate in a non-melting material state, electrical damage due to the melting material can be prevented.
[0081]
Claim 7 According to the described invention, since the underfill material is filled in the gap between the electronic component and the substrate by capillary action after the electronic component is mounted, the metal of the electronic component and the substrate can be obtained by the method of applying the underfill material before mounting the electronic component. The underfill material can be prevented from biting between the terminals, and high bonding reliability can be secured.
[0082]
Claim 8 According to the described invention, even if at least one of the electronic component and the substrate is an organic material, a ceramic material, a semiconductor material, or a composite thereof, a solid phase between these electronic components and each metal terminal of the substrate Intermetallic bonds by diffusion are obtained.
[0083]
Claim 9 According to the described invention, the electronic component holding mechanism, the substrate holding mechanism, and the positioning mechanism can Formed in a protruding shape With each metal terminal positioned and offset by 40% or more of the metal terminal diameter from the center position, the load is controlled by moving the electronic component relative to the board only in the vertical direction. Plastic deformation By each Since it is possible to make enough plastic deformation to destroy the oxide film on the metal terminal surface, the stress on the terminal surface accompanying the plastic deformation at this time becomes the driving force of solid phase diffusion, and the intermetallic bond is obtained, In addition, by applying a load by offsetting each metal terminal of the electronic component and the substrate, it is possible to cope with variations in height that differ depending on the metal terminal, a conventional mounting method by deformation of the protruding electrode, and a solid phase by ultrasonic vibration. Various problems that the diffusion method and the surface activation treatment method by energy wave irradiation have can be solved.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of an electronic component mounting apparatus according to the present invention.
2A and 2B show an embodiment of a method for mounting an electronic component according to the present invention, in which FIG. 2A is a plan sectional view showing a state in which the metal terminals of the substrate and the electronic component are offset and positioned; ) Is a side view thereof, (c) is a side view of a state where each metal terminal is metal-bonded, and (d) is a cross-sectional view of a state where an underfill material is filled in a gap between a substrate and an electronic component.
3A and 3B show a conventional electronic component mounting method, in which FIG. 3A is a plan sectional view showing a state in which the metal terminals of the substrate and the electronic component are positioned, FIG. 3B is a side view thereof, and FIG. It is a side view in the state where each metal terminal was metal-joined.
4A and 4B are side views showing offset amounts between metal terminals in the electronic component mounting method according to the present invention, in which FIG. 4A is a metal terminal that has been flattened and FIG. 4B is a metal that is not flattened. This is the case with terminals.
FIG. 5 is a graph of measured data showing the correlation between the offset amount and the bump plastic deformation amount.
FIG. 6 is a graph of actual measurement data showing the correlation between the offset amount, the dichroic strength, and the electrical jointability.
FIG. 7 is a photomicrograph showing the deformation state of the solder bump when the offset amount is 0 μm.
FIG. 8 is a photomicrograph showing the deformation state of the solder bump when the offset amount is 10 μm.
FIG. 9 is a photomicrograph showing the deformation state of the solder bump when the offset amount is 20 μm.
FIG. 10 is a micrograph showing a deformation state of a solder bump when the offset amount is 30 μm.
FIG. 11 is a photomicrograph showing the deformation state of the solder bump when the offset amount is 40 μm.
FIG. 12 is a micrograph showing a deformation state of a solder bump when the offset amount is 50 μm.
FIG. 13 is a photomicrograph showing the deformation state of the solder bump when the offset amount is 60 μm.
FIG. 14 is a micrograph showing a deformation state of a solder bump when the offset amount is 70 μm.
[Explanation of symbols]
21 Board
21a Metal terminal
22 Board holding mechanism
23 Positioning mechanism
24 electronic components
24a Metal terminal
25 Electronic component holding mechanism
26 Load control mechanism
31 Underfill material

Claims (9)

An electronic component having a metal terminal oxide film formed on the surface in the projection shape can be formed, when mounting on a metal terminal for bonding the oxide film on the surface formed with the protrusion shape on the substrate can be formed Applying a load by offsetting the terminal position of the electronic component with respect to the terminal position on the substrate by 40% or more of the terminal diameter ,
A method for mounting an electronic component, wherein the metal terminals of the electronic component and the substrate are plastically deformed to perform metal bonding . At least one of the electronic parts and each metal terminal of the substrate is
And the soft solder alloy, tin, lead, indium, mounting method of the electronic component of claim 1 Symbol mounting, characterized in that it is selected from at least one among the low-rigidity metal such as indium alloy. Electronic part mounting method according to claim 1 or 2, wherein the applying a load after the positioning of the electronic component to the substrate. Load, electronic part mounting method according to any one of claims 1 to 3, characterized in that it is applied only in the vertical direction. The electronic component mounting method according to any one of claims 1 to 4 , wherein the electronic component is mounted on the substrate in an unheated state. The electronic component mounting method according to any one of claims 1 to 5 , wherein the electronic component is mounted on the substrate in a non-melting material state. The electronic component mounting method according to any one of claims 1 to 6 , further comprising a step of filling an underfill material in a gap between the electronic component and the substrate by a capillary phenomenon after mounting the electronic component on the substrate. . The electronic component and at least one of the substrates, organic material, ceramic material, semiconductor material, an electronic component according to any one of claims 1 to 7, characterized in that it is selected from at least one among these complexes Implementation method. An electronic component holding mechanism for holding the electronic component;
A substrate holding mechanism for holding a substrate on which electronic components are mounted;
And a metal terminal electronic component oxide film formed on the surface in the protruding a projection shape formed surface to the metal terminal and the substrate having an oxide film may be formed of may be formed, electrons to the terminal position on the substrate A positioning mechanism for positioning the terminal position of the component by offsetting 40% or more of its metal terminal diameter;
The electronic component is moved relative to the substrate only in the vertical direction to apply a load between the metal terminal of the electronic component and the metal terminal of the substrate, and the load is controlled to control the load. An electronic component mounting apparatus comprising: a load control mechanism that plastically deforms a terminal to perform metal bonding.

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