JP2017107955A - Electronic device and method of manufacturing electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability by enhancing the strength of a joint part between electronic components.SOLUTION: An electronic device 1 includes: an electronic component 10 provided with an electrode 11; an electronic component 20 provided with an electrode 21 facing the electrode 11; and a joint part 30 joining the electrode 11 and the electrode 21. The joint part 30 comprises a portion 31 provided on a surface of the electrode 11, a portion 32 provided on a surface of the electrode 21, and a portion 33 provided between the portion 31 and the portion 32. The portion 31 contains a first solder having a first melting point. The portion 32 contains a second solder having a second melting point lower than the first melting point. The portion 33 contains a third solder containing respective components of the first solder and the second solder. The joint part 30 comprising the portion 31, the portion 32, and the portion 33 has a spherical outer shape.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electronic device and a method for manufacturing the electronic device.

  A technique for joining electronic components such as a semiconductor device and a circuit board using solder is known. For example, a solder bump is provided on the electrode on the semiconductor device side, a solder layer (solder paste) having a melting point lower than that of the solder bump is provided on the electrode on the circuit board side, and reflow is performed at a predetermined temperature. The technique of joining is known.

JP 2002-76605 A

  In the above technique, the reflow temperature is set to be higher than the melting point of the relatively high melting point solder bump provided on the electrode on the semiconductor device side, and the solder bump and the relatively low melting point provided on the circuit board side electrode. There is a technique in which the solder layers are fused together and joined together. However, in this method, a fragile compound is formed at the interface between the bonding portion and the electrode formed between the semiconductor device and the circuit board, and the strength of the bonding portion is insufficient with respect to shear stress, impact, or the like. is there.

  In the above technique, the solder layer provided on the electrode on the circuit board is selectively melted with respect to the solder bump provided on the electrode on the semiconductor device at the time of reflow. There is a technique of joining by a joining part having a shape in which the part is constricted. However, in such a joint, the force tends to concentrate on the constricted portion, and the strength of the joint may be insufficient with respect to shear stress or impact.

  The above-described insufficient strength of the joint portion is not limited to the joint portion between the semiconductor device and the circuit board, and can similarly occur at the joint portion between various electronic components. Insufficient strength of the joint between electronic components may reduce the reliability of the electronic device including them.

  According to an aspect of the present invention, a first electronic component including a first electrode, a second electronic component including a second electrode facing the first electrode, and the first electrode and the second electrode are joined. The bonding portion is provided on a surface of the first electrode, and is provided on a surface of the second electrode, a first portion including a first solder having a first melting point, and the first electrode. A second part including a second solder having a second melting point lower than the first melting point, and the first part and the second part, provided between the first part and the second part; There is provided an electronic device having a spherical outer shape, and a third portion including a third solder containing.

  According to another aspect of the present invention, a method for manufacturing the electronic device as described above is provided.

  According to the disclosed technology, a highly reliable electronic device with high strength at the joint between electronic components is realized.

It is a figure showing an example of junction between electronic parts concerning one form. It is a figure which shows an example of the electronic device which concerns on one form. It is a figure which shows an example of the joining between electronic components which concern on another form. It is a figure which shows an example of the electronic device which concerns on another form. It is a figure which shows an example of the joining between electronic components which concerns on 1st Embodiment. It is a figure which shows an example of the electronic device which concerns on 1st Embodiment. It is explanatory drawing of the junction part between electronic components which concerns on 1st Embodiment. It is a figure which shows the 1st example of the joining between electronic components which concerns on 2nd Embodiment. It is a figure which shows the 2nd example of the joining between electronic components which concerns on 2nd Embodiment. It is a figure which shows the 1st example of joining between electronic components which concerns on 3rd Embodiment. It is a figure which shows the 2nd example of the joining between electronic components which concerns on 3rd Embodiment. It is a figure which shows the structural example of a semiconductor chip. It is a figure which shows the structural example of a semiconductor package. It is a figure which shows another structural example of a semiconductor package. It is a figure which shows the structural example of a circuit board. It is a figure which shows an example of an electronic device.

First, one embodiment of the joint between electronic components and the electronic device will be described.
FIG. 1 is a diagram illustrating an example of the joining between electronic components according to one embodiment. FIG. 1A schematically illustrates an example of a cross-section of a main part before joining, and FIG. 1B schematically illustrates an example of a cross-section of a main part after joining.

An electronic component 110 and an electronic component 120 as shown in FIG. 1A are prepared.
The electronic component 110 has an electrode 111 on its surface. Solder bumps 112 are provided on the surface of the electrode 111. The solder bump 112 has a spherical outer shape.

The electronic component 120 has an electrode 121 on its surface. A solder layer 122 is provided on the surface of the electrode 121. For the solder layer 122, for example, a solder paste is used.
Solder having a predetermined melting point is used for the solder bump 112 provided on the surface of the electrode 111 of the electronic component 110 and the solder layer 122 provided on the surface of the electrode 121 of the electronic component 120. In this example, a solder having a melting point lower than that of the solder used for the solder bump 112 on the electronic component 110 side is used for the solder layer 122 on the electronic component 120 side.

  For the solder bump 112, for example, Sn—Ag—Cu based solder containing at least tin (Sn), silver (Ag) and copper (Cu) as components is used. As an example, the melting point of Sn-3.0Ag-0.5Cu solder having an Ag content of 3.0 wt% and a Cu content of 0.5 wt% is 217 ° C.

  When Sn-Ag-Cu solder is used for the solder bump 112, the solder layer 122 includes, for example, Sn-Bi solder containing at least Sn and bismuth (Bi) as components, or at least Sn and indium (as components). Sn-In solder containing In) is used. As an example, the melting point of Sn-57Bi solder having a Bi content of 57% by weight is 139 ° C. As an example, the melting point of Sn-52In solder having an In content of 52% by weight is 117 ° C.

  For the electronic component 110 and the electronic component 120, a semiconductor element (semiconductor chip), a semiconductor device (semiconductor package) including the semiconductor chip, a circuit board, or the like is used. For example, a semiconductor package is used for the electronic component 110 and a circuit board is used for the electronic component 120.

As shown in FIG. 1A, the electronic component 110 and the electronic component 120 having the above-described configuration are arranged to face each other with their electrodes 111 and 121 aligned.
Then, as shown in FIG. 1B, a solder bump 112 provided on the surface of the electrode 111 of the electronic component 110 and a solder layer 122 provided on the surface of the electrode 121 of the electronic component 120 are brought into contact with each other. Reflow is performed at a temperature of.

  In this example, reflow is performed on the solder bump 112 using a relatively high melting point solder at a temperature that selectively melts the solder layer 122 using a relatively low melting point solder. For example, reflow is performed at a temperature (peak temperature) about 20 ° C. higher than the melting point of the solder used for the solder layer 122. If Sn-3.0Ag-0.5Cu solder (melting point 217 ° C.) is used for the solder bump 112 and Sn-57Bi solder (melting point 139 ° C.) is used for the solder layer 122, reflow is performed at a temperature of about 160 ° C. Done.

  Sn-3.0Ag-0.5Cu solder has a melting point that is about 34 ° C. higher than that of Sn—Pb eutectic solder containing Sn and lead (Pb), and only Sn-3.0Ag-0.5Cu solder is used. When bonding is performed, reflow is performed at a temperature of about 240 ° C. Taking a semiconductor package as an example of the electronic component 110, the semiconductor package tends to increase in size from 30 mm to 50 mm as the integration density of semiconductor chips increases and the mounting density of chip components increases. When such a semiconductor package is bonded to a bonding partner electronic component 120, for example, a circuit board, by using a solder bump 112 of Sn-3.0Ag-0.5Cu solder provided thereon, during reflow at about 240 ° C. , The stress and strain generated at the joints are increased. As a result, there is an increased possibility that cracks and breaks will occur at the joint. On the other hand, a solder paste of Sn-57Bi solder having a melting point lower than that of Sn-3.0Ag-0.5Cu solder is provided on the circuit board as the solder layer 122, and is selectively melted at a temperature of about 160 ° C. According to the above reflow method, bonding at a temperature as low as about 80 ° C. is possible. The above-described method of joining the solder bumps 112 using the solder layer 122 using solder having a lower melting point has an advantage that such low-temperature joining is possible.

In the case where a solder paste is used for the solder layer 122, the solder layer 122 causes the volatilization of the resin and the like as the contained solder melts due to heating during reflow.
By performing reflow at a predetermined temperature, the electronic component 110 and the electronic component 120 are mechanically and electrically bonded by the bonding portion 130a including the solder bump 112 and the solder layer 122 as shown in FIG. The electronic device 100a is obtained.

FIG. 2 illustrates an example of an electronic device according to one embodiment. FIG. 2 schematically shows an enlarged portion X of FIG.
In the electronic device 100a obtained by the method shown in FIG. 1A and FIG. 1B, the solder bumps that are not melted at the time of reflow are formed in the joint portion 130a that joins the electronic component 110 and the electronic component 120. 112 and a melted solder layer 122 are included.

  In the joint portion 130 a, the solder bump 112 that remains in a spherical shape without being melted is joined to the melted solder layer 122. The melted solder layer 122 has a shape in which the width (diameter) increases from the solder bump 112 side toward the electrode 121 side. That is, the melted solder layer 122 forms a fillet 131 at the tip of the spherical solder bump 112. For this reason, the joint portion 130a has a partially constricted shape as shown in FIG.

  In such a joint 130 a, a narrowed portion with a narrow width exists between the electrode 111 of the electronic component 110 and the electrode 121 of the electronic component 120. Further, in the joint portion 130a, physical property values such as an elastic modulus and a linear expansion coefficient of the solder bump 112 and the solder layer 122 that are joined are different. Due to these points, the joint 130a becomes weak against high strain due to shear stress, impact, etc., and the strength as a mechanical and electrical joint between the electronic component 110 and the electronic component 120 is insufficient. Sometimes. For example, due to the difference in the constricted shape and physical properties, the constricted part or the joint interface between the solder bump 112 and the solder layer 122 cannot withstand high strain due to shear stress, impact, etc. Breakage (disconnection) occurs.

  In the method according to this embodiment, low-temperature bonding is possible as described above. However, on the other hand, the joint portion 130a between the electronic component 110 and the electronic component 120 has a constricted shape with the solder bump 112 and the solder layer 122 (fillet 131), resulting in insufficient strength of the joint portion 130a. Cracks and breaks may occur. Insufficient strength of the joint 130a between the electronic component 110 and the electronic component 120, and cracks and fractures resulting from the strength cause a decrease in the reliability of the electronic device 100a, such as a desired operation not being realized in the electronic device 100a.

Subsequently, another embodiment of the bonding between electronic components and the electronic device will be described.
FIG. 3 is a diagram illustrating an example of the joining between electronic components according to another embodiment. FIG. 3A schematically illustrates an example of a cross-section of a main part before joining, and FIG. 3B schematically illustrates an example of a cross-section of a main part after joining.

  As shown in FIG. 3B, the electronic component 110 and the electronic component 120 as described above are arranged to face each other with their electrodes 111 and 121 aligned as shown in FIG. 3A. , Reflowed at a predetermined temperature and joined.

  In this example, the reflow is performed at a temperature at which the solder bump 112 using a relatively high melting point solder and the solder layer 122 using a relatively low melting point solder are melted together. For example, reflow is performed at a temperature (peak temperature) that is equal to or higher than the melting point of the solder used for the solder bump 112 and about 20 ° C. higher than the melting point of the solder. If Sn-3.0Ag-0.5Cu solder (melting point 217 ° C.) is used for the solder bump 112, reflow is performed at a temperature of about 240 ° C.

In the case where a solder paste is used for the solder layer 122, the solder layer 122 causes the volatilization of the resin and the like as the contained solder melts due to heating during reflow.
By performing reflow at a predetermined temperature, an electronic device 100b in which the electronic component 110 and the electronic component 120 are mechanically and electrically bonded by the bonding portion 130b as shown in FIG. 3B is obtained.

FIG. 4 is a diagram illustrating an example of an electronic apparatus according to another embodiment. FIG. 4 schematically shows an enlarged Y portion of FIG.
In the electronic device 100b obtained by the method shown in FIGS. 3A and 3B, the joint 130b that joins the electronic component 110 and the electronic component 120 has the solder bump 112 and the solder layer 122 by reflow. Are melted together and have an integrated structure. The joint portion 130b becomes spherical (also called a sphere-like shape or a drum shape) due to the surface tension of the melted solder bump 112 and solder layer 122.

At the time of reflow in which such a joining part 130b is formed, a relatively fragile compound 132 is formed at the interface between the joining part 130b and the electrode 111 of the electronic component 110, for example, as shown in FIG. In the case where Sn-Ag-Cu solder is used for the solder bump 112 and Sn-Bi solder is used for the solder layer 122, Cu ₃ Sn or Sn is present at the interface with the electrode 111 of the joint 130b obtained by reflow. An intermetallic compound such as Cu ₆ Sn ₅ is formed. Furthermore, Bi diffusion and precipitation of Sn—Bi solder melted by reflow can occur at the interface between the bonding portion 130 b and the electrode 111. As a result, a relatively fragile compound 132 is formed at the interface between the bonding portion 130b and the electrode 111.

  The joint 130b in which the relatively fragile compound 132 is formed is weak against high strain due to shear stress, impact, or the like, and the strength as a mechanical and electrical joint between the electronic component 110 and the electronic component 120 is increased. There may be a shortage. For example, the relatively weak compound 132 of the joint 130b cannot withstand high strain due to shear stress, impact, or the like, and the joint 130b is cracked or broken.

  In the method according to another embodiment, the joint 130b between the electronic component 110 and the electronic component 120 is not a constricted shape like the joint 130a (FIGS. 1 and 2) described in the above embodiment, but a spherical shape. It becomes possible to do. However, on the other hand, since the relatively fragile compound 132 is formed at the bonding interface, there is a possibility that the strength of the bonding portion 130b is insufficient, and cracks and breaks due to the strength are generated. Insufficient strength of the joint portion 130b between the electronic component 110 and the electronic component 120, and cracks and breaks resulting from the strength cause a decrease in the reliability of the electronic device 100b, such as a desired operation not being realized in the electronic device 100b.

In view of the above points, here, a technique as exemplified below is used to suppress the insufficient strength of the joint between electronic components.
First, the first embodiment will be described.

  FIG. 5 is a diagram illustrating an example of bonding between electronic components according to the first embodiment. FIG. 5A schematically illustrates an example of a cross-section of a main part before joining, and FIG. 5B schematically illustrates an example of a cross-section of a main part after joining.

An electronic component 10 and an electronic component 20 as shown in FIG. 5A are prepared.
The electronic component 10 has an electrode 11 on its surface (one main surface). Various conductive materials are used for the electrode 11. For example, the electrode 11 is made of Cu or a material containing Cu, or aluminum (Al) or a material containing Al. On the surface layer portion of the electrode 11, a layer (underlayer) such as a laminate (Ni / Au) of nickel (Ni) and gold (Au), a laminate of Ni, palladium (Pd) and Au (Ni / Pd / Au), or the like. A bump metal (UBM) layer may be provided.

  Solder bumps 12 are provided on the surface of the electrode 11 of the electronic component 10. The solder bumps 12 have a spherical shape, that is, an outer shape like a rounded sphere. Such a spherical solder bump 12 is formed by, for example, a method of mounting a solder ball on the electrode 11 and reflowing, a method of forming a solder on the electrode 11 using a plating method, and reflowing. .

  The electronic component 20 which is a bonding partner of the electronic component 10 has an electrode 21 on the surface (one main surface). Various conductive materials are used for the electrode 21. For example, the electrode 21 is made of Cu or a material containing Cu, or Al or a material containing Al. On the surface layer portion of the electrode 21, a layer such as Ni / Au or Ni / Pd / Au may be provided as a UBM layer.

  A solder layer 22 is provided on the surface of the electrode 21 of the electronic component 20. The solder layer 22 is formed by, for example, a method of applying a solder paste (a resin composition containing solder particles in a predetermined resin such as a flux) on the electrode 21 using a printing method or the like.

  Solder having a predetermined melting point is used for the solder bump 12 provided on the surface of the electrode 11 of the electronic component 10 and the solder layer 22 provided on the surface of the electrode 21 of the electronic component 20. In this example, a solder having a melting point lower than that of the solder used for the solder bump 12 on the electronic component 10 side is used for the solder layer 22 on the electronic component 20 side. Various solders having a melting point of 200 ° C. or higher are used for the solder bumps 12, and various solders having a melting point of 150 ° C. or lower are used for the solder layer 22.

  For example, the solder bump 12 is made of Sn—Ag—Cu solder containing at least Sn, Ag and Cu as components. In addition to Sn, Ag, and Cu, a small amount of antimony (Sb), zinc (Zn), Bi, In, or the like may be added to the Sn—Ag—Cu based solder. As an example, the melting point of Sn-3.0Ag-0.5Cu solder having an Ag content of 3.0 wt% and a Cu content of 0.5 wt% is 217 ° C.

  When Sn-Ag-Cu solder is used for the solder bumps 12, the solder layer 22 includes, for example, Sn-Bi solder containing at least Sn and Bi as components, or Sn containing at least Sn and In as components. -In solder is used. In addition to Sn and Bi, a trace amount of Cu, Zn, Ag, Sb, In, or the like may be added to the Sn—Bi series solder. In addition to Sn and In, a trace amount of Sn, In, or Bi may be added. Cu, Zn, Ag, Sb, Bi, or the like may be added. As an example, the melting point of Sn-57Bi solder having a Bi content of 57% by weight is 139 ° C. As an example, the melting point of Sn-52In solder having an In content of 52% by weight is 117 ° C. Note that when a certain amount of Ag or Sb is added to the Sn—Bi solder or Sn—In solder, the ductility of the solder layer 22 and the joint 30 described later is enhanced.

  As the electronic component 10 and the electronic component 20, a semiconductor chip, a semiconductor package including the semiconductor chip, a circuit board, or the like is used. For example, a semiconductor package is used for the electronic component 10 and a circuit board is used for the electronic component 20. Configuration examples of semiconductor chips, semiconductor packages, and circuit boards used as the electronic component 10 and the electronic component 20 will be described later (FIGS. 12 to 15).

As shown in FIG. 5A, the electronic component 10 and the electronic component 20 as described above are disposed so as to face each other with the electrodes 11 and 21 aligned.
Then, as shown in FIG. 5B, the solder bump 12 provided on the surface of the electrode 11 of the electronic component 10 and the solder layer 22 provided on the surface of the electrode 21 of the electronic component 20 are brought into contact with each other. Reflow is performed at a temperature of. In this example, reflow is performed at a temperature (peak temperature) that is lower than the melting point of the solder used for the solder bump 12 and about 40 ° C. higher than the melting point of the solder used for the solder layer 22.

  For example, if Sn-3.0Ag-0.5Cu solder (melting point: 217 ° C.) is used for the solder bump 12 and Sn-57Bi solder (melting point: 139 ° C.) is used for the solder layer 22, from about 180 ° C. to 216 ° C. Reflow is performed at a temperature within the range of. If Sn-3.0Ag-0.5Cu solder (melting point 217 ° C.) is used for the solder bump 12 and Sn-52In solder (melting point 117 ° C.) is used for the solder layer 22, the range from about 160 ° C. to 216 ° C. Reflow is performed at the temperature inside. The upper limit of the reflow temperature is set according to the melting point of the solder used for the solder bump 12, and the lower limit of the reflow temperature is set according to the melting point of the solder used for the solder layer 22. Since the upper limit of the temperature at the time of reflow is less than the melting point of the solder used for the solder bumps 12, low-temperature bonding is possible as compared with the case where only the solder bumps 12 are bonded without using the solder layer 22.

When a solder paste is used for the solder layer 22, the solder layer 22 is heated during reflow, and the contained solder melts and the resin volatilizes.
By performing reflow at a predetermined temperature, the electronic device 1 in which the electronic component 10 and the electronic component 20 are mechanically and electrically bonded by the bonding portion 30 as shown in FIG. 5B is obtained.

FIG. 6 is a diagram illustrating an example of the electronic apparatus according to the first embodiment. FIG. 6 schematically shows an enlarged Z portion in FIG.
In the electronic device 1 obtained by the method shown in FIGS. 5A and 5B, the joint 30 that joins the electronic component 10 and the electronic component 20 may be, for example, FIG. 6 (and FIG. 5 ( B)), three parts 31, 32 and 33 are included.

  The part 31 is provided on the surface of the electrode 11 on the electronic component 10 side. The part 31 is a part (core) where the solder bump 12 remains without being melted during reflow. The portion 31 contains components of the solder bump 12 (Sn, Ag, Cu, etc.). The portion 31 is smaller in size (diameter) than the solder bump 12 before reflow because the surface layer portion of the solder bump 12 is melted during reflow.

  The part 32 is provided on the surface of the electrode 21 on the electronic component 20 side. The part 32 is a part formed by melting the solder layer 22 during reflow. The part 32 contains components (Sn, Bi, In, etc.) of the solder layer 22 before reflow. The part 32 may further contain components of the electrode 21 (Cu, Ni, Au, Pd, etc.).

  The part 33 is provided between the part 31 on the electrode 11 side and the part 32 on the electrode 21 side. The part 33 is a part formed by mutually diffusing the mutual components of the solder layer 22 melted during reflow and the surface layer part of the solder bump 12. The part 33 contains the components (Sn, Bi, In, etc.) of the solder layer 22 before reflow and the components (Sn, Ag, Cu, etc.) of the solder bumps 12. The portion 33 can further contain components of the electrode 21 (Cu, Ni, Au, Pd, etc.) diffused into the solder layer 22 that is melted during reflow.

  In the joint portion 30, the portion 33 containing the mutual components of the solder layer 22 melted during reflow and the surface layer portion of the solder bump 12 is arranged to surround the portion 31 where the solder bump 12 remains without being melted during reflow. Become. The part 32 formed by melting the solder layer 22 during reflow is arranged to further surround the part 33 surrounding the part 31.

  The joint part 30 including the part 31, the part 32, and the part 33 has a spherical shape, that is, an outer shape like a rounded sphere. The shape of the joint portion 30 as shown in FIG. 6 is such that the width (diameter) of the intermediate portion is larger than the width (diameter) of both end portions (both joint interfaces between the electrode 11 and the electrode 21) on the electrode 11 and electrode 21 side. ) Is also called a drum shape.

The junction 30 of the electronic device 1 will be further described.
FIG. 7 is an explanatory diagram of a joint part between electronic components according to the first embodiment. For comparison, FIG. 7A schematically illustrates a cross section of an essential part of an electronic device having a constricted joint, and FIG. 7B illustrates an essential part of the electronic device having a spherical joint. A partial cross section is schematically shown.

First, a constricted joint 30a as shown in FIG.
Of the solder bumps 12 and the solder layer 22, in reflow at a temperature at which the solder layer 22 is selectively melted, for example, at a temperature of about 160 ° C. when Sn-57Bi solder is used for the solder layer 22, The fillet 35 is formed by selectively melting the solder layer 22. A constricted joint portion 30a is formed by the fillet 35 and the solder bump 12 remaining without being melted.

  In the process of forming the constricted joint portion 30a, the solder bump 12 comes into contact with the solder layer 22 to be melted, so that the components of the surface layer portion can be dissolved into the solder layer 22. However, since the reflow temperature is much lower than the melting point of the solder bump 12, for example, 217 ° C. when Sn-3.0Ag-0.5Cu solder is used for the solder bump 12, The portion that remains in the solid phase without being melted becomes relatively large.

In a range where the size R _B of the solid phase portion of the solder bump 12 exceeds a predetermined reference size R _S (R _B > R _S ), the molten solder layer 22 becomes solid phase of the solder bump 12 due to surface tension. I can't scoop up the club. As a result, the melted solder layer 22 remains below the solid phase portion of the solder bump 12 to form a fillet 35, and the joint 30a obtained after reflow has a constricted shape as shown in FIG. Become.

Subsequently, a spherical joint 30 as shown in FIG. 7B will be described.
When forming the joint 30 as shown in FIG. 7B, reflow is performed at a temperature lower than the melting point of the solder used for the solder bumps 12 and higher than the melting point of the solder used for the solder layer 22. Done. However, the reflow is performed at a higher temperature than when forming the constricted joint portion 30a as described above, for example, at a higher temperature of 180 ° C. or higher if Sn-57Bi solder is used for the solder layer 22. For example, if Sn-3.0Ag-0.5Cu solder (melting point 217 ° C.) is used for the solder bump 12 and Sn-57Bi solder (melting point 139 ° C.) is used for the solder layer 22, the range is 180 ° C. to 216 ° C. Then, reflow is performed.

When reflowing is performed under such conditions, the component (mainly Sn) of the surface portion of the solder bump 12 that comes into contact with the molten solder layer 22 and has a higher temperature than the inside melts into the molten solder layer 22, The surface layer portion of the solder bump 12 is melted. By surface layer portion of the solder bump 12 is melted, the size R _B of the solid phase portion of the solder bumps 12 that remains without being melted it becomes smaller. Further, the component of the surface layer portion (mainly Sn) to be melted is melted into the molten solder layer 22 to increase the amount of liquid phase solder. When the solid phase portion of the solder bump 12 is reduced to a reference size R _S or less (R _B ≦ R _S ), the increased amount of liquid phase solder crawls up to the upper portion of the solder bump 12 due to surface tension. To cover the solid phase part.

  The solid phase portion of the solder bump 12 remains on the surface of the electrode 11 even after reflow, and the remaining solid phase portion becomes the portion 31 shown in FIG. 7B and FIG. Around that, a part containing the mutual components of the solder bump 12 (surface layer part) and the solder layer 22 (liquid phase solder in which Sn is melted) melted at the time of reflow is formed, and this part is shown in FIG. And the region 33 shown in FIG. A part containing the component of the solder layer 22 melted at the time of reflow is formed around and on the surface of the electrode 21, and this part becomes the part 32 shown in FIG. 7B and FIG.

Thus, the size R _B of the solid phase portion of the solder bumps 12, the liquidus solder is less crawling Agareru such reference size R _S by the surface tension, the junction of the constricted shape as shown in FIG. 7 (A) Instead of 30a, a spherical joint 30 as shown in FIG. 7B and FIG. 6 is formed. That is, the temperature of the size R _B of the solid phase portion has a shape change such that below a predetermined reference size R _S of the solder bumps 12 occurs, for example, reflow is carried out at a temperature such 180 ℃ ~216 ℃ described above, spherical A junction 30 is formed.

If the solder layer 22 provided on the electrode 21 in advance is below a certain amount, the solder bump 12 is reduced in size by melting of the surface layer portion at the time of reflow, and the components of the surface layer portion are dissolved in the solder layer 22 to cause liquid phase soldering. Even if the amount is increased, there is a possibility that no creeping due to surface tension occurs. Therefore, in order to form the spherical joint 30, in addition to the temperature at the time of reflow and the change in the shape of the solder bump 12 due to the reflow (size R _B of the solid phase portion that remains unmelted), The amount (thickness) of the solder layer 22 to be provided is also taken into consideration.

  As described above, the spherical joint 30 including the part 31, the part 32, and the part 33 is more resistant to high strain due to shear stress, impact, or the like than the constricted joint 30a. That is, in the constricted joint portion 30a, the constricted portion where the force tends to concentrate is unable to withstand shear stress, impact, or the like, and there is a risk of cracking or breaking. On the other hand, in the spherical joint portion 30, the concentration of local forces that can occur in the constricted joint portion 30a is suppressed, and it is possible to effectively suppress the occurrence of cracks and fractures due to shear stress, impact, and the like. it can.

  Further, in the spherical joint 30, the solid phase part of the solder bump 12 that is not melted at the time of joining by reflow remains on the surface of the electrode 11 of the electronic component 10 as a part 31. Therefore, it is possible to suppress the formation of a relatively fragile compound at the interface between the electrode 30 and the bonding portion 30 formed at the time of bonding by reflow, and to effectively cause cracks and breakage due to such a compound. Can be suppressed. Furthermore, the core portion 31 containing the component of the solder bump 12 is surrounded by the portion 33 containing both the component of the solder bump 12 and the solder layer 22, and these are further surrounded by the portion 32 containing the component of the solder layer 22. This contributes to improving the strength of the joint 30 against shear stress, impact, and the like.

  By joining the electronic component 10 and the electronic component 20 mechanically and electrically with the spherical joint 30 including the part 31, the part 32, and the part 33 as described above, the strength of the joint 30 is insufficient, and the cause thereof. Thus, the highly reliable electronic device 1 can be realized.

Specific examples of the manufacture and configuration of the electronic device 1 including the joint 30 as described in the first embodiment are shown as Examples 1 to 10 below.
[Example 1]
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 11 of the semiconductor package. After applying flux on the electrode 11 on which the UBM layer is formed, a solder ball of Sn-3.0Ag-0.5Cu solder (Ag: 3.0 wt%, Cu: 0.5 wt%) is applied to a metal mask. It was arranged by the method of transferring to the opening. Then, reflow was performed in a nitrogen (N ₂ ) atmosphere (oxygen (O ₂ ) concentration of 100 ppm or less) under a peak temperature of 240 ° C., solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi solder (Bi: 57 wt%) was disposed as the solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The joint portion 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds and contains Sn and Bi. It was confirmed by elemental analysis to include the portion 32 on the electrode 21.

[Example 2]
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Pd / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi solder was disposed as a solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The joint portion 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds and contains Sn and Bi. It was confirmed by elemental analysis to include the portion 32 on the electrode 21.

Example 3
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi-1Ag solder (Bi: 57 wt%, Ag: 1 wt%) was disposed as a solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds the portion 31 and includes Sn, Bi, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

Example 4
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Pd / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi-1Ag solder was disposed as a solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds the portion 31 and includes Sn, Bi, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

Example 5
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi-0.4Ag solder (Bi: 57 wt%, Ag: 0.4 wt%) is applied to the solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask. Arranged as.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds the portion 31 and includes Sn, Bi, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

Example 6
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Pd / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-57Bi-0.4Ag solder was disposed as the solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 180 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, Bi, Ag, and Cu, and further surrounds the portion 31 and includes Sn, Bi, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

Example 7
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-52In solder (In: 52% by weight) was disposed as the solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 160 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, In, Ag, and Cu, and further surrounds and contains Sn and In. It was confirmed by elemental analysis to include the portion 32 on the electrode 21.

Example 8
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Pd / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-52In solder was disposed on the electrode 21 of the circuit board as the solder layer 22 by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 160 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The junction 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, In, Ag, and Cu, and further surrounds and contains Sn and In. It was confirmed by elemental analysis to include the portion 32 on the electrode 21.

Example 9
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-52In-0.3Ag solder (In: 52% by weight, Ag: 0.3% by weight) is applied onto the electrode 21 of the circuit board by a printing method using a metal mask. Arranged as.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 160 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The joint portion 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, In, Ag, and Cu, and further surrounds the portion 31 and includes Sn, In, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

Example 10
As an electronic component 10 (FIG. 5), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 11 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Pd / Au UBM layer was formed on the electrode 11 of the semiconductor package. After the flux was applied on the electrode 11 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) under a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 11, and solder bumps 12 were formed.

  As the electronic component 20 (FIG. 5), an FR-4 circuit board having a planar size of 110 mm × 110 mm in width and provided with Cu electrodes 21 corresponding to the electrodes 11 of the electronic component 10 (semiconductor package) was prepared. A solder paste containing Sn-52In-0.3Ag solder was disposed as the solder layer 22 on the electrode 21 of the circuit board by a printing method using a metal mask.

The electronic component 10 (semiconductor package) in which the solder bumps 12 are provided on the corresponding electrode 11 is temporarily fixed on the electronic component 20 (circuit board) having the solder layer 22 disposed on the electrode 21 by positioning. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature of 160 ℃ ~216 ℃. Thereby, the electronic device 1 (FIG. 5 and FIG. 6) in which the electronic component 10 and the electronic component 20 were joined by the spherical joining part 30 was obtained.

  About the spherical joining part 30 of the obtained electronic device 1, the cross section was observed and evaluated. The joint portion 30 includes a portion 31 on the electrode 11 containing Sn, Ag, and Cu, and surrounds the portion 31 containing Sn, In, Ag, and Cu, and further surrounds the portion 31 and includes Sn, In, and Ag. It was confirmed by elemental analysis that it contains the part 32 on the electrode 21 containing.

In addition to the electronic device 1 as shown in Examples 1 to 10 above, for comparison, an electronic device 100a as shown in the following Comparative Example 1 and an electronic device 100b as shown in Comparative Example 2 were obtained.
[Comparative Example 1]
As an electronic component 110 (FIG. 1), a semiconductor package having a planar size of 42.5 mm long × 42.5 mm wide, a Cu electrode 111 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 111 of the semiconductor package. After applying flux on the electrode 111 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) at a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 111, and the solder bumps 112 were formed.

  As an electronic component 120 (FIG. 1), an FR-4 circuit board having a planar size of 110 mm × width 110 mm and provided with Cu electrodes 121 corresponding to the electrodes 111 of the electronic component 110 (semiconductor package) was prepared. A solder paste containing Sn-57Bi solder was disposed as a solder layer 122 on the electrode 121 of the circuit board by a printing method using a metal mask.

An electronic component 110 (semiconductor package) in which solder bumps 112 are provided on a corresponding electrode 111 is positioned and temporarily fixed on an electronic component 120 (circuit board) having a solder layer 122 disposed on the electrode 121. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature 160 ° C.. As a result, an electronic device 100a (FIGS. 1 and 2) was obtained in which the electronic component 110 and the electronic component 120 were joined by the constricted joint 130a.
[Comparative Example 2]
As an electronic component 110 (FIG. 3), a semiconductor package having a plane size of 42.5 mm long × 42.5 mm wide, a Cu electrode 111 (pad) diameter of 0.76 mm, a pitch of 1.27 mm, and a number of 1089 Prepared. A Ni / Au UBM layer was formed on the electrode 111 of the semiconductor package. After applying flux on the electrode 111 on which the UBM layer was formed, a solder ball of Sn-3.0Ag-0.5Cu solder was placed by a method of swinging into the opening of the metal mask. Then, reflow was performed in an N ₂ atmosphere (O ₂ concentration of 100 ppm or less) at a peak temperature of 240 ° C., the solder balls were mounted on the electrodes 111, and the solder bumps 112 were formed.

  As an electronic component 120 (FIG. 3), an FR-4 circuit board having a planar size of 110 mm × width 110 mm and provided with Cu electrodes 121 corresponding to the electrodes 111 of the electronic component 110 (semiconductor package) was prepared. A solder paste containing Sn-57Bi solder was disposed as a solder layer 122 on the electrode 121 of the circuit board by a printing method using a metal mask.

An electronic component 110 (semiconductor package) in which solder bumps 112 are provided on a corresponding electrode 111 is positioned and temporarily fixed on an electronic component 120 (circuit board) having a solder layer 122 disposed on the electrode 121. . Then, N ₂ atmosphere (O ₂ concentration 100ppm or less) were reflow conditions a peak temperature 240 ° C.. Thereby, the electronic device 100b (FIG. 3 and FIG. 4) with which the electronic component 110 and the electronic component 120 were joined by the spherical junction part 130b was obtained.

Next, the results of evaluating the reliability of the electronic device 1 will be described.
About the electronic device 1 obtained in Examples 1-10, after confirming that there was no problem in electrical performance, a repeated temperature cycle test of −40 ° C. to 105 ° C. was performed 1000 cycles. In any of the electronic devices 1 of Examples 1 to 10, it was confirmed that the resistance increase was as good as 10% or less.

  Moreover, after confirming that there was no problem in electrical performance, the electronic device 1 obtained in Examples 1 to 10 was left in an environment of a temperature of 100 ° C. and a humidity of 85% for 1000 hours. In any of the electronic devices 1 of Examples 1 to 10, it was confirmed that the resistance increase was as good as 10% or less.

  Moreover, the drop impact test was implemented about the electronic device 1 of Examples 1-10, the electronic device 100a of the comparative example 1, and the electronic device 100b of the comparative example 2. FIG. The drop impact test was performed up to 100 times under the condition of an impact acceleration of 1500 G by a method in accordance with JEDEC (Joint Electron Device Engineering Council) JESD22-B111. As electronic device 1 of Examples 1-10, what is obtained by reflow of peak temperature 180 ° C and what is obtained by reflow of peak temperature 200 ° C are prepared, these, electronic device 100a of comparative example 1, and comparison The electronic device 100b of Example 2 was subjected to the drop impact test. As a result, the electronic devices 1 having the peak temperatures of 180 ° C. and 200 ° C. of Examples 1 to 10 both showed a drop impact life of 30 times or more, whereas the electronic devices 100a and 2 of Comparative Example 1 Both the drop impact lives of the electronic device 100b were 30 times or less.

  As described above, in the first embodiment, the solder bump 12 and the solder layer 22 are reflowed at a predetermined temperature to form the spherical joint 30 including the part 31, the part 32, and the part 33. To do. Thereby, the joint part 30 with high strength is realized. By joining the electronic component 10 and the electronic component 20 by such a joining part 30, the highly reliable electronic device 1 is implement | achieved.

Next, a second embodiment will be described.
FIG. 8 is a diagram illustrating a first example of bonding between electronic components according to the second embodiment. FIG. 8A schematically illustrates an example of a cross-section of a main part before joining, and FIG. 8B schematically illustrates an example of a cross-section of a main part after joining.

  For example, an electronic component 10 and an electronic component 20 as shown in FIG. 8A are prepared. The electrode 21 of the electronic component 20 has a size (width) equal to or smaller than the electrode 11 of the electronic component 10. Here, as an example, the case where the size of the electrode 21 of the electronic component 20 is smaller than the size of the electrode 11 of the electronic component 10 is illustrated.

  Solder bumps 12 using relatively high melting point solder are provided on the surface of the electrode 11 of the electronic component 10, and solder layers 22 using relatively low melting point solder are provided on the surface of the electrode 21 of the electronic component 20. It is done. Thus, the electrode 21 of the electronic component 20 provided with the solder layer 22 containing a relatively low melting point solder is sized so as not to exceed the size of the corresponding electrode 11 of the electronic component 10.

  8B, the solder bumps 12 provided on the surface of the electrode 11 of the electronic component 10 and the solder layer 22 provided on the surface of the electrode 21 of the electronic component 20 are brought into contact with each other. Reflow is performed at a predetermined temperature as described in the first embodiment. Thereby, as shown in FIG. 8B, an electronic device 1a in which the electronic component 10 and the electronic component 20 are mechanically and electrically bonded with high reliability at the spherical bonding portion 30 is obtained. In this example, the size of the bonding interface between the bonding portion 30 and the electrode 21 is the same as or smaller than the size of the bonding interface between the bonding portion 30 and the electrode 11.

  Here, at the time of reflow when joining the electronic component 10 and the electronic component 20, the lateral spread of the solder layer 22 to be melted is defined by the size of the electrode 21. The larger the size of the electrode 21, the larger the range in which the melted solder layer 22 spreads sideways. When the range in which the melted solder layer 22 spreads laterally increases, fillets may be formed, thereby forming a constricted joint.

  Therefore, as described above, the size of the electrode 21 is set so as not to exceed the size of the corresponding electrode 11. Thereby, since the spread of the melted solder layer 22 can be suppressed within the size range of the electrode 21, formation of fillets and formation of a constricted joint can be effectively suppressed.

  FIG. 9 is a diagram illustrating a second example of bonding between electronic components according to the second embodiment. FIG. 9A schematically illustrates an example of a cross section of a main part before joining, and FIG. 9B schematically illustrates an example of a cross section of a main part after joining.

  The lateral spread of the solder layer 22 melted during reflow can be defined by the size (width) of the electrode 21 itself as in the first example. In addition, the lateral spread of the solder layer 22 melted during reflow can be defined by the opening size (opening width) of a protective film such as a solder resist provided on the surface of the electronic component 20. That is, the opening of the protective film provided so that the electrode 21 is exposed is made to be the same size as the electrode 11 of the electronic component 10 or smaller than the electrode 11 of the electronic component 10.

  As an example, FIG. 9A illustrates a case where the size of the opening 23 a of the protective film 23 provided on the surface of the electronic component 20 is smaller than that of the electrode 11 of the electronic component 10. By setting the opening 23a of the protective film 23 to such a size, the size of the electrode 21 exposed from the opening 23a is set so as not to exceed the size of the electrode 11 of the electronic component 10 corresponding thereto.

  As a result, as described in the first example, the spread of the solder layer 22 melted at the time of reflow is suppressed to the size range of the electrode 21 exposed from the opening 23a of the protective film 23. Even with the method as in the second example, the formation of fillets and the formation of a constricted joint can be effectively suppressed, and a spherical joint 30 as shown in FIG. An electronic device 1b in which the electronic component 20 is mechanically and electrically joined with high reliability is obtained. Also in this example, the size of the bonding interface between the bonding portion 30 and the electrode 21 is the same as or smaller than the size of the bonding interface between the bonding portion 30 and the electrode 11.

  Here, an example of adjusting the size of the electrode 21 of the electronic component 20 or the size of the electrode 21 exposed from the protective film 23 provided on the surface of the electronic component 20 in order to obtain the spherical joint 30 has been shown. In addition, in order to obtain the spherical joint 30, the size of the electrode 11 of the electronic component 10 or the size of the electrode 11 exposed from the protective film provided on the surface of the electronic component 10 can be adjusted.

Next, a third embodiment will be described.
FIG. 10 is a diagram illustrating a first example of bonding between electronic components according to the third embodiment. In FIG. 10, an example of the principal part cross section at the time of joining is typically shown.

  For example, when the electronic device 1 described in the first embodiment is obtained, the solder bump 12 provided on the surface of the electrode 11 of the electronic component 10 and the surface of the electrode 21 of the electronic component 20 are provided. The solder layer 22 is contacted and reflow is performed at a predetermined temperature.

At the time of this reflow, for example, the electronic component 10 and the electronic component 20 can be heated as a whole so that the solder bump 12 and the solder layer 22 have a desired temperature.
In addition, at the time of reflow, as shown in FIG. 10, heating 40 can be performed from the electronic component 20 side. For example, using a heater such as a heater, heating 40 is performed from the surface of the electronic component 20 opposite to the surface on which the electrode 21 is disposed.

  When heating 40 is performed from the electronic component 20 side, the solder layer 22 provided on the surface of the electrode 21 of the electronic component 20 and the surface layer portion of the solder bump 12 provided on the surface of the electrode 11 of the electronic component 10 are melted by the temperature rise. On the other hand, the temperature rise inside the solder bump 12 can be suppressed. By suppressing the temperature rise inside the solder bump 12, it is relatively fragile at the interface between the solid portion of the solder bump 12 that remains without being melted and the electrode 11 of the electronic component 10 in the joint 30 to be formed. Formation of such a compound (compound 132 shown in FIG. 4 above) is more effectively suppressed.

Thus, the spherical joint 30 including the part 31, the part 32, and the part 33 may be obtained by performing the heating 40 from the electronic component 20 side.
FIG. 11 is a diagram illustrating a second example of bonding between electronic components according to the third embodiment. FIG. 11 schematically shows an example of a cross-section of the main part at the time of joining.

  At the time of reflow when joining the electronic component 10 and the electronic component 20, as shown in FIG. 11, the heating 40 can be performed from the electronic component 20 side and the cooling 50 can be performed from the electronic component 10 side. For example, using a heater such as a heater, heating 40 is performed from the surface of the electronic component 20 opposite to the surface where the electrode 21 is disposed, and a cooling device such as a fan is used to heat the electrode 11 of the electronic component 10. Cooling 50 is performed from the side opposite to the arrangement surface.

As described above, the spherical joint 30 including the portion 31, the portion 32, and the portion 33 may be obtained by performing the heating 40 from the electronic component 20 side and the cooling 50 from the electronic component 10 side.
In the electronic component 10 and the electronic component 20 according to the first to third embodiments described above, the electrode 11 and the electrode 21 can be used as pads, and can be fixed from the surface of the electronic component 10 and the electronic component 20. It can also be a post (pillar) protruding at a height.

  Moreover, a semiconductor chip, a semiconductor package, a pseudo SoC (System on a Chip), a circuit board, etc. can be used for the electronic component 10 and the electronic component 20 which concern on the 1st-3rd embodiment described above. Examples of these configurations will be described with reference to FIGS. 12 to 15 below.

FIG. 12 is a diagram illustrating a configuration example of a semiconductor chip. FIG. 12 schematically shows a cross section of the main part of an example of the semiconductor chip.
A semiconductor chip 200 illustrated in FIG. 12 includes a semiconductor substrate 210 provided with circuit elements such as transistors, and a wiring layer 220 provided on a surface 210 a of the semiconductor substrate 210.

  As the semiconductor substrate 210, a substrate such as gallium arsenide (GaAs) or indium phosphide (InP) is used in addition to a substrate such as silicon (Si), germanium (Ge), or silicon germanium (SiGe). Such a semiconductor substrate 210 is provided with circuit elements such as transistors, capacitors, and resistors. FIG. 12 shows a MOS (Metal Oxide Semiconductor) transistor 230 as an example.

  The MOS transistor 230 is provided in an element region defined by an element isolation region 211 provided in the semiconductor substrate 210. The MOS transistor 230 has a gate electrode 232 formed on the semiconductor substrate 210 via a gate insulating film 231, and a source region 233 and a drain region 234 formed in the semiconductor substrate 210 on both sides of the gate electrode 232. An insulating film spacer 235 (side wall) is provided on the side wall of the gate electrode 232.

  A wiring layer 220 is provided on the semiconductor substrate 210 provided with such a MOS transistor 230 and the like. The wiring layer 220 includes a conductor portion 221 (wiring, via, etc.) electrically connected to the MOS transistor 230 or the like provided on the semiconductor substrate 210 and an insulating portion 222 that covers the conductor portion 221. Various conductor materials such as Cu are used for the conductor portion 221. For the insulating part 222, an inorganic insulating material such as SiO or an organic insulating material such as resin is used.

  The wiring layer 220 is provided with an electrode 221 a that is electrically connected to the conductor portion 221. Here, a pad is illustrated as the electrode 221a, but the electrode 221a may be a post. The solder bump 12 or the solder layer 22 is provided on the surface of the electrode 221a.

FIG. 13 is a diagram illustrating a configuration example of a semiconductor package. FIG. 13A and FIG. 13B each schematically show a cross section of an essential part of an example of a semiconductor package.
A semiconductor package 300A illustrated in FIG. 13A and a semiconductor package 300B illustrated in FIG. 13B include a package substrate 310, a semiconductor chip 320 mounted on the package substrate 310, and a seal for sealing the semiconductor chip 320. Layer 330.

  For example, a printed circuit board is used as the package substrate 310. The package substrate 310 includes a conductor portion 311 (wiring, via, etc.) and an insulating portion 312 that covers the conductor portion 311. Various conductor materials such as Cu are used for the conductor portion 311. For the insulating portion 312, a resin material such as a phenol resin, an epoxy resin, or a polyimide resin, a composite resin material in which such a resin material is impregnated with glass fiber or carbon fiber, or the like is used.

  In the semiconductor package 300 </ b> A of FIG. 13A, the semiconductor chip 320 is bonded and fixed to the surface 310 a of the package substrate 310 with a die attach material 341 such as resin or conductive paste, and wire-bonded with a wire 350. The semiconductor chip 320 and the wire 350 are sealed with a sealing layer 330. Further, in the semiconductor package 300B of FIG. 13B, the semiconductor chip 320 is flip-chip connected to the surface 310a of the package substrate 310 by the solder bumps 321. An underfill resin 342 is filled between the package substrate 310 and the semiconductor chip 320. The semiconductor chip 320 is sealed with a sealing layer 330. For the sealing layer 330, a resin material such as an epoxy resin, a material in which an insulating filler is contained in such a resin material, or the like is used.

  An electrode 311 a electrically connected to the conductor portion 311 is provided on the back surface 310 b of the package substrate 310. Here, a pad is illustrated as the electrode 311a, but the electrode 311a may be a post. The solder bump 12 or the solder layer 22 is provided on the surface of the electrode 311a.

  A plurality of semiconductor chips 320 of the same type or different types may be mounted on the package substrate 310 of the semiconductor package 300A and the semiconductor package 300B. In addition to the semiconductor chip 320, other electronic components such as a chip capacitor may be included. It may be mounted.

FIG. 14 is a diagram showing another configuration example of the semiconductor package. FIG. 14 schematically shows a cross section of a main part of another example of the semiconductor package.
A semiconductor package 400 shown in FIG. 14 is provided on the resin layer 410, a plurality of semiconductor chips 420 of the same type or different types (two as an example here) embedded in the resin layer 410, and the surface 410a of the resin layer 410. And a wiring layer 430 (rewiring layer). The semiconductor package 400 is also referred to as pseudo SoC or the like.

  The semiconductor chip 420 is embedded in the resin layer 410 so that the arrangement surface of the terminal 421 is exposed. The wiring layer 430 includes a conductor portion 431 (rewiring, via, etc.) such as Cu and an insulating portion 432 such as a resin material that covers the conductor portion 431.

  The wiring layer 430 is provided with an electrode 431 a that is electrically connected to the conductor portion 431. Here, a pad is illustrated as the electrode 431a, but the electrode 431a may be a post. The solder bump 12 or the solder layer 22 is provided on the surface of the electrode 431a.

  In addition, one semiconductor chip 420 or three or more semiconductor chips 420 of the same kind or different kinds may be embedded in the resin layer 410 of the semiconductor package 400. In addition to the semiconductor chip 420, other than a chip capacitor or the like. The electronic component may be embedded.

FIG. 15 is a diagram illustrating a configuration example of a circuit board. FIG. 15 schematically illustrates a cross-section of an essential part of an example of a circuit board.
FIG. 15 illustrates a multilayer wiring board including a plurality of wiring layers as the circuit board 500. The circuit board 500 includes a conductor portion 511 (wiring, via, etc.) such as Cu and an insulating portion 512 such as a resin material that covers the conductor portion 511.

  An electrode 511 a electrically connected to the conductor portion 511 is provided on the surface of the circuit board 500. Here, a pad is illustrated as the electrode 511a, but the electrode 511a may be a post. The solder bump 12 or the solder layer 22 is provided on the surface of the electrode 511a.

  Various electronic components such as the semiconductor chip 200 shown in FIG. 12, the semiconductor packages 300 </ b> A, 300 </ b> B, and 400 shown in FIGS. 13 and 14, and the circuit board 500 shown in FIG. 15 are electronic devices according to the first to third embodiments. It can be used for the component 10 and the electronic component 20.

  The electronic devices 1, 1a, 1b and the like according to the first to third embodiments described above can be used for various electronic devices (also referred to as electronic devices). For example, it can be used for various electronic devices such as computers (personal computers, supercomputers, servers, etc.), smart phones, mobile phones, tablet terminals, sensors, cameras, audio devices, measuring devices, inspection devices, and manufacturing devices.

FIG. 16 illustrates an example of an electronic device. FIG. 16 schematically illustrates an example of an electronic device.
As shown in FIG. 16, for example, the electronic device 1 as shown in FIGS. 5 and 6 is mounted (built in) in various electronic devices 60 as exemplified above. In the electronic device 1, the electronic component 10 and the electronic component 20 are mechanically and electrically joined to each other by the spherical joint 30 including the part 31, the part 32, and the part 33 and having high strength and reliability. As a result, a highly reliable electronic device 1 is realized, and a highly reliable electronic device 60 equipped with such an electronic device 1 is realized.

Regarding the embodiment described above, the following additional notes are further disclosed.
(Additional remark 1) The 1st electronic component provided with the 1st electrode,
A second electronic component comprising a second electrode facing the first electrode;
A joining portion for joining the first electrode and the second electrode;
The joint is
A first portion provided on a surface of the first electrode and including a first solder having a first melting point;
A second portion including a second solder provided on a surface of the second electrode and having a second melting point lower than the first melting point;
A third portion provided between the first portion and the second portion and including a third solder containing the components of the first solder and the second solder and having a spherical outer shape; An electronic device characterized by that.

(Supplementary Note 2) The third part surrounds the first part,
The electronic device according to appendix 1, wherein the second part surrounds the third part surrounding the first part.

(Supplementary Note 3) The first melting point is 200 ° C or higher,
The electronic device according to appendix 1 or 2, wherein the second melting point is 150 ° C or lower.

(Supplementary Note 4) The first solder includes tin, silver, and copper.
The electronic device according to any one of appendices 1 to 3, wherein the second solder contains tin and bismuth, or tin and indium.

(Supplementary note 5) The electronic device according to supplementary note 4, wherein the second solder further contains silver.
(Supplementary Note 6) The second size of the bonding interface between the bonding portion and the second electrode is the same as or smaller than the first size of the bonding interface between the bonding portion and the first electrode. The electronic device according to any one of appendices 1 to 5, characterized in that:

  (Additional remark 7) The said junction part is an intermediate part of a said 1st electrode and a said 2nd electrode rather than the 1st size of the junction interface with a said 1st electrode, and the 2nd size of the junction interface with a said 2nd electrode. The electronic device according to any one of appendices 1 to 6, wherein the third size is a large drum shape.

(Additional remark 8) The process of joining the 1st electrode of a 1st electronic component and the 2nd electrode of the 2nd electronic component facing the said 1st electrode by a junction part,
The joint is
A first portion provided on a surface of the first electrode and including a first solder having a first melting point;
A second portion including a second solder provided on a surface of the second electrode and having a second melting point lower than the first melting point;
A third portion provided between the first portion and the second portion and including a third solder containing the components of the first solder and the second solder and having a spherical outer shape; A method for manufacturing an electronic device.

(Supplementary Note 9) The third part surrounds the first part,
The method of manufacturing an electronic device according to appendix 8, wherein the second part surrounds the third part surrounding the first part.

  (Additional remark 10) The process of joining the said 1st electrode and the said 2nd electrode by the said junction part is provided in the surface of the said 1st electrode, the solder bump containing the said 1st solder, and the surface of the said 2nd electrode 10. The electron according to appendix 8 or 9, comprising a step of contacting the solder layer including the second solder and heating at a temperature higher than the second melting point and lower than the first melting point. Device manufacturing method.

  (Supplementary Note 11) The step of heating at a temperature above the second melting point and less than the first melting point includes a step of heating at a temperature that is 40 ° C. higher than the second melting point and less than the first melting point. Item 11. The method for manufacturing an electronic device according to Item 10, wherein:

  (Additional remark 12) The 2nd size of the area | region in which the said solder layer of the said 2nd electrode is provided is the same as the 1st size of the area | region in which the said solder bump is provided in the said 1st electrode, or is more than the said 1st size. Item 12. The method for manufacturing an electronic device according to Item 10 or 11, wherein the method is small.

  (Supplementary Note 13) The step of heating at a temperature above the second melting point and less than the first melting point is performed from the second electronic component side of the first electronic component and the second electronic component. 13. The method for manufacturing an electronic device according to any one of appendices 10 to 12, further comprising a step of heating at a temperature exceeding the melting point and less than the first melting point.

(Supplementary Note 14) The first melting point is 200 ° C or higher,
14. The method for manufacturing an electronic device according to any one of appendices 8 to 13, wherein the second melting point is 150 ° C. or lower.

(Supplementary Note 15) The first solder includes tin, silver, and copper.
15. The method of manufacturing an electronic device according to any one of appendices 8 to 14, wherein the second solder includes tin and bismuth, or tin and indium.

1, 1a, 1b, 100a, 100b Electronic device 10, 20, 110, 120 Electronic component 11, 21, 111, 121, 221a, 311a, 431a, 511a Electrode 12, 112, 321 Solder bump 22, 122 Solder layer 23 Protection Membrane 23a Opening 30,30a, 130a, 130b Joint 31,32,33 Site 35,131 Fillet 40 Heating 50 Cooling 60 Electronic device 132 Compound 200, 320, 420 Semiconductor chip 210 Semiconductor substrate 210a, 310a, 410a Surface 211 element Isolation region 220, 430 Wiring layer 221, 311, 431, 511 Conductor portion 222, 312, 432, 512 Insulating portion 230 MOS transistor 231 Gate insulating film 232 Gate electrode 233 Source region 234 Drain region 235 Spa Sa 300A, 300B, 400 semiconductor package 310 package substrate 310b back surface 330 sealing layer 341 die attach material 342 underfill resin 350 wire 410 resin layer 421 terminal 500 circuit board

Claims (8)

A first electronic component comprising a first electrode;
A second electronic component comprising a second electrode facing the first electrode;
A joining portion for joining the first electrode and the second electrode,
The joint is
A first portion provided on a surface of the first electrode and including a first solder having a first melting point;
A second portion including a second solder provided on a surface of the second electrode and having a second melting point lower than the first melting point;
A third portion provided between the first portion and the second portion and including a third solder containing the components of the first solder and the second solder and having a spherical outer shape; An electronic device characterized by that. The third part surrounds the first part;
The electronic device according to claim 1, wherein the second part surrounds the third part surrounding the first part. The first melting point is 200 ° C. or higher,
The electronic device according to claim 1, wherein the second melting point is 150 ° C. or lower. The first solder includes tin, silver and copper,
The electronic device according to claim 1, wherein the second solder contains tin and bismuth, or tin and indium. Joining the first electrode of the first electronic component and the second electrode of the second electronic component facing the first electrode by a joint portion;
The joint is
A first portion provided on a surface of the first electrode and including a first solder having a first melting point;
A second portion including a second solder provided on a surface of the second electrode and having a second melting point lower than the first melting point;
A third portion provided between the first portion and the second portion and including a third solder containing the components of the first solder and the second solder and having a spherical outer shape; A method for manufacturing an electronic device. The third part surrounds the first part;
The method of manufacturing an electronic device according to claim 5, wherein the second part surrounds the third part surrounding the first part.   The step of bonding the first electrode and the second electrode by the bonding portion includes a solder bump provided on the surface of the first electrode and including the first solder, and provided on the surface of the second electrode. The method for manufacturing an electronic device according to claim 5, further comprising a step of contacting a solder layer including the second solder and heating at a temperature above the second melting point and less than the first melting point. Method.   The step of heating at a temperature above the second melting point and less than the first melting point includes a step of heating at a temperature that is 40 ° C. or more higher than the second melting point and less than the first melting point. An electronic device manufacturing method according to claim 7.

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