JP2001148552A - Mounting structure and mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure and a mounting method, which can maintain flexibility of printed board mounting area array components and improve service life, even when a mounting structure is made into a two-stage structure. SOLUTION: In a mounting structure 1, a module board 4 as a printed board, on which area array components 6 are mounted with a plurality of solder balls 5 for connecting components is mounted on a mother board 2. A plurality of solder balls 3 for connecting the boards are gathered in the central part of the module board 4. Thereby the flexibility of the module board 4 mounting the area array components 6 can be ensured, even when the mounting structure 1 is made into a two-stage structure, so that shearing strain due to the difference in coefficients of thermal expansion can be reduced, and the service life of the mounting structure 1 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mounting structure and a mounting method, and more particularly, to a mounting structure and a mounting method for appropriately connecting even when a substrate is warped or uneven.

[0002]

2. Description of the Related Art In general, printed circuit boards are formed by forming solder balls in an array on one printed circuit board and mounting them on electrodes of opposite positions on the other printed circuit board.
The connection is made by fusion connection.

Conventionally, as shown in FIG. 14, a printed circuit board connected to a mother board 101 is a CSP.
In the case of the module substrate 102 on which the area array component 103 having a (chip size package) or BGA (ball grid array) structure is mounted, the array connection is performed in a two-stage structure, and the connection is performed in a two-stage structure. However, there is a problem that solder reflow is repeated at least twice, and a failure such as breakage of a connection portion occurs due to a difference in thermal expansion coefficient between the mounted component 103 such as CSP or BGA and the module substrate 102. .

That is, for example, as shown in FIG.
FIG.
As shown by the arrow in Fig. 5, according to the difference between thermal expansion and contraction,
Since the warpage occurs moderately, the distortion between the CSP 105 and the module substrate 106 is reduced.

[0005] However, as shown in FIG.
The board on which the area array component 107 is mounted, that is,
In the two-stage structure in which the module substrate 108 is mounted on the mother substrate 109, since the intermediate module substrate 108 is connected to the mother substrate 109, the degrees of freedom are restricted as shown by arrows in FIGS. There was a possibility that an appropriate warpage did not occur, a shear strain was increased, and a failure such as breakage of a connection portion occurred. In particular, module substrate 1
08 and the mother board 109, the solder balls 11
17 is arranged around the module substrate 108 and fixed, as shown in FIG. 17, the module substrate 108 becomes rigid, that is, in a constrained state. It's easy to do.

Therefore, in order to solve the above problem, a semiconductor device in which a substrate is mounted in an L-shape to reduce shear strain due to a difference in linear expansion coefficient has been conventionally known (Japanese Patent Laid-Open No. 7-201916).
And circuit components to be mounted on a printed circuit board are formed by solder bumps having a high melting point, and the components mounted on the printed circuit board are joined by solder having a lower melting point than the solder bumps, and the difference in the coefficient of thermal expansion is increased. (See Japanese Patent Application Laid-Open No. 8-64717) has been proposed.

[0007]

However, such a conventional method of connecting a printed circuit board is not an appropriate solution and has a problem to be solved.

That is, in the semiconductor device described in Japanese Patent Application Laid-Open No. 7-201916, since the substrate is mounted in an L-shape, it is difficult to route the wiring on the intermediate substrate.
There have been problems that the number of lead wires is limited and the structure of the connection part is complicated.

In the method of mounting a circuit component described in Japanese Patent Application Laid-Open No. 8-64717, the circuit component is formed by solder bumps having a high melting point, and mounting on a printed circuit board is performed at a lower temperature than the solder bumps. Since the bonding is performed using the melting point solder, it is necessary to change the material of the solder to be bonded to the solder bump of the circuit component, and there has been a problem that the cost is increased.

In view of the above, according to the first aspect of the present invention, a plurality of board connection solder balls for mounting a printed board on which an area array component is mounted on a mother board with a plurality of component connection solder balls are provided. By maintaining the degree of freedom of the module substrate on which the area array components are mounted and reducing the shear strain due to the difference in the thermal expansion coefficient even when the mounting structure is a two-stage structure, It is another object of the present invention to provide a mounting structure capable of extending the life.

According to a second aspect of the present invention, a printed circuit board on which an area array component is mounted with a plurality of component connecting solder balls arranged in an array is mounted on a mother board with a plurality of board connecting solder balls. In this case, the area array components and the solder balls for board connection are arranged in a state of being displaced from each other in a vertical positional relationship, so that even when the mounting structure is a two-stage structure, the module for mounting the area array components is mounted. While maintaining the flexibility of the board, simplifying the arrangement of the solder balls for connecting the board, reducing the shear strain due to the difference in thermal expansion coefficient, extending the service life, and making the wiring on the mother board easier. It is an object of the present invention to provide a mounting structure that can perform the following.

According to a third aspect of the present invention, a supporting solder ball for supporting a printed circuit board is disposed on a portion of the mother board where the board connecting solder ball is not located, and the supporting solder ball is reflowed to be wet. By spreading it away from the printed circuit board, the printed circuit board tilts during mounting due to the imbalance in the solder ball layout, preventing soldering errors between the printed circuit board and the mother board due to the solder balls for board connection, and area array components. The purpose of the present invention is to provide a mounting structure that reduces the shear strain due to the difference in thermal expansion coefficient while maintaining the degree of freedom of the module board on which the board is mounted, and ensures the bonding between the printed board and the mother board and prolongs the service life. And

According to a fourth aspect of the present invention, a supporting electrode having a surface area larger than a surface area of an electrode for connecting a solder ball for connecting a substrate is formed at a position where a solder ball for supporting a mother board is arranged, and the supporting electrode is formed. No electrode is formed on the printed circuit board at the position facing the electrode, and the supporting solder balls are placed on the supporting electrode and reflowed to spread the support electrode and spread it away from the printed circuit board. The printed circuit board tilts during mounting due to the imbalance in the layout of the solder balls, preventing solder balls for connection between the printed circuit board and the mother board from being erroneously joined and maintaining the flexibility of the module board on which the area array components are mounted. To reduce the shear strain due to the difference in the coefficient of thermal expansion, ensure the connection between the printed circuit board and the motherboard, and extend the service life. And its object is to provide a mounting structure capable of Kusuru.

According to a fifth aspect of the present invention, there is provided a supporting solder ball, wherein a through-hole is formed at a position where the supporting solder ball of the mother board is arranged, and no electrode is formed on the printed circuit board at a position facing the through-hole. Is placed on the through-hole and reflowed so that it spreads in the through-hole and separates it from the printed circuit board, causing the printed circuit board to tilt during mounting due to the imbalance in the solder ball layout. To prevent mistakes in joining the printed circuit board and mother board due to
A mounting structure that maintains the flexibility of the module board on which the area array components are mounted, reduces the shear strain due to the difference in thermal expansion coefficient, ensures the connection between the printed board and the mother board, and extends the service life. It is intended to provide.

According to a sixth aspect of the present invention, a plurality of board-connecting solder balls for mounting a printed board on which an area array component is mounted on a mother board with a plurality of component-connecting solder balls are provided at the center of the printed board. By disposing them close to each other, even when the mounting structure is a two-stage structure, the flexibility of the module board on which the area array components are mounted is maintained, and the shear strain due to the difference in the thermal expansion coefficient is reduced, and the life is shortened. The purpose is to provide an implementation method that can lengthen the time.

According to a seventh aspect of the present invention, a printed board on which an area array component is mounted by a plurality of component connection solder balls arranged in an array is mounted on a mother board by a plurality of board connection solder balls. In this case, the area array components and the solder balls for board connection are arranged in a state of being displaced from each other in a vertical positional relationship, so that even when the mounting structure is a two-stage structure, the module for mounting the area array components is mounted. While maintaining the flexibility of the board, simplifying the arrangement of the solder balls for connecting the board, reducing the shear strain due to the difference in thermal expansion coefficient, extending the service life, and making the wiring of the mother board easier. The purpose is to provide an implementation method that can do this.

According to an eighth aspect of the present invention, a supporting solder ball for supporting a printed circuit board is disposed on a portion of the mother board where the board connecting solder ball is not located, and the supporting solder ball is reflowed. By spreading it away from the printed circuit board, the printed circuit board tilts during mounting due to the imbalance in the solder ball layout, preventing soldering errors between the printed circuit board and mother board due to the solder balls for connecting the board, and the area array. Keeping the flexibility of the module board on which components are mounted,
It is an object of the present invention to provide a mounting method capable of reducing a shear strain due to a difference in thermal expansion coefficient, securely connecting a printed board and a mother board, and extending a life.

According to a ninth aspect of the present invention, a supporting electrode having a surface area larger than a surface area of an electrode for connecting a solder ball for connecting a substrate is formed at a position where a solder ball for supporting a mother board is arranged, and No electrodes are formed on the printed circuit board at the position facing the electrodes, and the supporting solder balls are placed on the supporting electrodes and reflowed so that they spread on the supporting electrodes and separate from the printed circuit board. The printed circuit board tilts during mounting due to the imbalance in the layout of the solder balls, preventing solder balls for connection between the printed circuit board and the mother board from being erroneously joined and maintaining the flexibility of the module board on which the area array components are mounted. To reduce the shear strain due to the difference in the coefficient of thermal expansion, ensure the connection between the printed circuit board and the mother board, And its object is to provide a mounting method capable of lengthening.

According to a tenth aspect of the present invention, a through hole is formed at a position where a supporting solder ball of a mother board is arranged,
No electrode is formed on the printed circuit board at the position facing the through-hole, and the supporting solder balls are arranged on the through-hole and reflowed so that they are spread in the through-hole and separated from the printed circuit board. The printed circuit board tilts during mounting due to the imbalance in the layout of the solder balls, preventing solder balls for connection between the printed circuit board and the mother board from being erroneously joined and maintaining the flexibility of the module board on which the area array components are mounted. Reduce the shear strain due to the difference in thermal expansion coefficient,
It is an object of the present invention to provide a mounting method for reliably joining a printed board and a mother board and extending the life.

[0020]

According to a first aspect of the present invention, there is provided a mounting structure, wherein a printed circuit board on which an area array component is mounted by a plurality of component connecting solder balls arranged in an array is used. In the mounting structure in which the solder balls are mounted on the mother board, the above-described object is achieved by disposing the board connecting solder balls near the center of the printed board.

According to the above configuration, a plurality of board connection solder balls for mounting the printed circuit board on which the area array components are mounted on the mother board with the plurality of component connection solder balls are provided at the center of the printed board. Since they are arranged close to each other, even when the mounting structure is a two-stage structure, the degree of freedom of the printed circuit board on which the area array components are mounted can be maintained, and the shear strain due to the difference in the thermal expansion coefficient can be reduced. Thus, the life of the mounting structure can be extended.

According to a second aspect of the present invention, there is provided a printed circuit board on which an area array component is mounted by a plurality of component connecting solder balls arranged in an array, and a plurality of board connecting solder balls on a mother board. In the mounting structure mounted in the above, the above-mentioned object is achieved by disposing the area array components and the board connection solder balls so as to be displaced from each other in a vertical positional relationship.

According to the above arrangement, when the printed circuit board on which the area array components are mounted by the plurality of component connection solder balls arranged in an array is mounted on the mother board by the plurality of substrate connection solder balls. Since the area array components and the solder balls for board connection are arranged in a state of being displaced from each other in a vertical positional relationship, the mounting structure is
Even in the case of a stepped structure, the degree of freedom of the printed circuit board on which the area array components are mounted can be maintained, the arrangement of the solder balls for connecting the boards can be simplified, and the shear strain due to the difference in thermal expansion coefficient can be reduced. By reducing the length, the life can be prolonged and the wiring on the mother substrate side can be easily arranged.

In each of the above cases, for example, as described in claim 3, the mother board is provided with a supporting solder ball for supporting the printed board at a portion where the board connecting solder ball is not located. The supporting solder ball may be wet and spread by being reflowed, and may be separated from the printed circuit board.

According to the above arrangement, the supporting solder balls for supporting the printed circuit board are arranged on the portion of the mother board where the board connecting solder balls are not located, and the supporting solder balls are reflowed so as to be spread. The printed circuit board is separated from the printed circuit board, so the printed circuit board tilts during mounting due to the imbalance in the layout of the solder balls. Maintaining the degree of freedom of the module board on which the array components are mounted, reducing the shear strain due to the difference in thermal expansion coefficient, ensuring the connection between the printed board and the mother board, and extending the life. Can be.

For example, as set forth in claim 4, the mother board has a surface area larger than a surface area of an electrode for connecting the board connection solder balls at a position where the support solder balls are arranged. A supporting electrode is formed, and no electrode is formed on the printed circuit board at a position facing the supporting electrode, and the supporting solder ball is disposed on the supporting electrode and reflowed. Thus, the support electrode may be wet and spread, and may be separated from the printed circuit board.

According to the above configuration, a supporting electrode having a surface area larger than the surface area of the electrode for connecting the substrate connecting solder ball is formed at the position where the supporting solder ball of the mother substrate is arranged, and the supporting electrode is formed. Since no electrodes are formed on the printed circuit board facing the position, the solder balls for support are arranged on the support electrodes and reflowed, so that the support electrodes are wetted and spread and separated from the printed circuit board. The printed circuit board tilts during mounting due to the imbalance in the solder ball layout, which prevents the printed circuit board and mother board from being bonded incorrectly by the solder balls for connecting the boards, and the degree of freedom of the module board on which the area array components are mounted. And the shear strain due to the difference in thermal expansion coefficient can be reduced, and the printed board and mother board can be securely bonded. It is possible, it is possible to increase the life.

Further, for example, as set forth in claim 5, the mother board has a through hole formed at a position where the supporting solder ball is disposed, and the mother board has a through hole formed at a position facing the through hole. No electrodes are formed, and the supporting solder balls are arranged on the through holes and reflowed, so that they spread in the through holes and are separated from the printed circuit board. Good.

According to the above configuration, a through hole is formed at the position where the supporting solder ball of the mother board is arranged, and no electrode is formed on the printed board at a position facing the supporting electrode. The printed circuit board is placed on the through hole and reflowed so that it spreads in the through hole and separates it from the printed circuit board. In addition to preventing the bonding error between the printed board and the mother board due to the balls, the degree of freedom of the module board on which the area array components are mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced. This ensures that the substrate and the mother substrate can be joined, and also extends the life.

According to a sixth aspect of the present invention, there is provided a mounting method, wherein a printed circuit board on which an area array component is mounted by a plurality of component connecting solder balls is arranged on a mother board by a plurality of board connecting solder balls. The above object is achieved by disposing the board connection solder balls close to the center of the printed circuit board.

According to the above arrangement, a plurality of board connection solder balls for mounting the printed circuit board on which the area array components are mounted on the mother board with the plurality of component connection solder balls are provided at the center of the printed board. Since they are arranged close to each other, even when the mounting structure is a two-stage structure, the degree of freedom of the module substrate on which the area array component is mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced. , The service life can be extended.

According to a seventh aspect of the present invention, in the mounting method, a printed circuit board on which an area array component is mounted with a plurality of component connecting solder balls arranged in an array is placed on a mother board with a plurality of board connecting solder balls. The above object is achieved by disposing the area array components and the board connection solder balls in a vertically displaced relationship with each other.

According to the above configuration, when the printed circuit board on which the area array components are mounted by the plurality of solder balls for connecting the components arranged in an array is mounted on the mother board by the plurality of solder balls for connecting the substrates. Since the area array components and the solder balls for board connection are arranged in a state of being displaced from each other in a vertical positional relationship, the mounting structure is
Even in the case of a stepped structure, the degree of freedom of the module board on which the area array component is mounted can be maintained, and the arrangement of the solder balls for board connection can be simplified,
It is possible to reduce the shear strain due to the difference in the thermal expansion coefficient, prolong the service life, and to facilitate the wiring of the wiring on the mother substrate side.

In each of the above cases, for example, as set forth in claim 8, the mounting method includes a step of supporting the printed board on a portion of the mother board where the board connecting solder balls are not located. A solder ball may be arranged, and the supporting solder ball may be wet-spread by reflowing and separated from the printed circuit board.

According to the above configuration, the supporting solder balls for supporting the printed circuit board are arranged on the portions of the mother board where the board connecting solder balls are not located, and the supporting solder balls are reflowed to spread the solder balls. Since the printed circuit board is separated from the printed circuit board, the printed circuit board is inclined at the time of mounting due to the imbalance in the layout of the solder balls, and it is possible to prevent the bonding error between the printed circuit board and the mother board due to the solder balls for board connection, and
The degree of freedom of the module board on which the area array components are mounted can be maintained, the shear strain due to the difference in thermal expansion coefficient can be reduced, the printed board and the mother board can be securely joined, and the life is prolonged. be able to.

Also, for example, in the above mounting method, the mounting method may be such that a surface area of an electrode for connecting the board connecting solder ball is provided at a position on the mother board where the supporting solder ball is arranged. Forming a supporting electrode having a larger surface area, forming no electrode on the printed circuit board at a position facing the supporting electrode, disposing the supporting solder ball on the supporting electrode, and The solder balls for use may be reflowed so as to wet and spread on the supporting electrodes and be separated from the printed circuit board.

According to the above configuration, a supporting electrode having a surface area larger than the surface area of the electrode for connecting the substrate connecting solder ball is formed at the position of the supporting solder ball on the mother substrate. Since no electrodes are formed on the printed circuit board at the position opposite to, the supporting solder balls are arranged on the supporting electrodes and reflowed, so that the supporting electrodes are spread over the supporting electrodes and separated from the printed circuit board.
The printed circuit board tilts during mounting due to the imbalance in the solder ball layout, which prevents the printed circuit board and mother board from being bonded incorrectly by the solder balls for connecting the boards, and the degree of freedom of the module board on which the area array components are mounted. , The shear strain due to the difference in the coefficient of thermal expansion can be reduced, the printed board and the mother board can be reliably joined, and the life can be prolonged.

Further, for example, as set forth in claim 10, in the mounting method, a through hole is formed at a position where the supporting solder ball is arranged on the mother board, and the through hole is formed at a position facing the through hole. No electrodes are formed on the printed circuit board, the supporting solder balls are arranged on the through holes, and the supporting solder balls are reflowed so as to be wet-spread in the through holes and from the printed circuit board. May be separated.

According to the above configuration, a through hole is formed at the position where the supporting solder ball of the mother board is arranged, and no electrode is formed on the printed board at a position facing the through hole, and the supporting solder ball is used. Since it is placed on the through hole and reflowed, it spreads in the through hole and separates it from the printed circuit board, so the printed circuit board is inclined at the time of mounting due to the imbalance of the solder ball layout, and the solder ball for board connection In addition to preventing the bonding error between the printed board and the mother board, the degree of freedom of the module board on which the area array components are mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced. The mother substrate can be securely bonded and the life can be prolonged.

[0040]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 and 2 show a first embodiment of a mounting structure and a mounting method of the present invention. FIG. 1 shows a first embodiment of a mounting structure and a mounting method of the present embodiment. FIG. 3 is a front view of a mounting structure 1 showing the embodiment.

In FIG. 1, the mounting structure 1 has a solder ball (solder ball for board connection) on the upper surface of the mother board 2.
A module substrate 4 is bonded and mounted by 3, and an area array component 6 such as BGA or CSP is bonded and mounted on the module substrate 4 by a solder ball (solder ball for component connection) 5.

As shown in FIG. 2, the solder balls 3 joining the module substrate 4 to the mother substrate 2 are sequentially laid out from the center of the module substrate 4, and all the solder balls 3 are connected to the center of the module substrate 4. It is formed in a state where it is gathered in a part (closed state).

On the module substrate 4, as described above,
Four area array components 6 are joined and mounted by the solder balls 3, and the four area array components 6
It is mounted near four corners of the module substrate 4.

Therefore, most of the area array components 6 mounted on the module substrate 4 are located outside the area of the solder balls 3 joining the module substrate 4 to the mother substrate 2.

As described above, the mounting structure 1 of the present embodiment
A module board 4, which is a printed board on which an area array component 6 is mounted with a plurality of component connecting solder balls 5, is mounted on a mother board 2 by a plurality of board connecting solder balls 3. It is arranged near the center of the substrate 4.

Therefore, even when the mounting structure 1 has a two-stage structure, the degree of freedom of the module substrate 4 on which the area array component 6 is mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced. The life of the mounting structure 1 can be extended.

That is, even when the difference in the coefficient of thermal expansion during mounting is large between the mother board 2 and the module board 4,
The area array component 6 replaces the module substrate 4 with the mother substrate 2
Since the majority of the solder balls 3 are located outside the area of the solder balls 3 bonded thereon, the degree of freedom of the module substrate 4 can be maintained, the shear strain due to the difference in thermal expansion coefficient can be reduced, and the life of the mounting structure 1 can be extended. Can be extended.

FIG. 3 is a diagram showing a mounting structure and a mounting method according to a second embodiment of the present invention. FIG. 3 is a diagram showing a mounting structure and a mounting method according to a second embodiment of the present invention.
0 is a perspective plan view of FIG.

In FIG. 3, the mounting structure 10 has a single area array component 12 mounted on a module substrate 11 by joining with solder balls (solder balls for component connection) 13. No solder ball on mother board (solder ball for board connection)
14 and are mounted.

The area array component 12 is mounted near one corner of the module substrate 11, and the solder balls 14 for mounting the module substrate 11 on the mother board are located outside the area of the area array component 12. Are located in

As described above, the mounting structure 10 of the present embodiment
Mounts a module board 11 which is a printed board on which an area array component 12 is mounted with a plurality of component connecting solder balls 13 arranged in an array on a mother board with a plurality of board connecting solder balls 14. At this time, the area array component 12 and the solder balls 14 for connecting the board are arranged in a state of being displaced from each other in a vertical positional relationship.

Therefore, even when the mounting structure 10 has a two-stage structure, the degree of freedom of the module substrate 11 on which the area array components 12 are mounted can be maintained, and the arrangement of the solder balls 14 for connecting the substrates can be simplified. It is possible to reduce the shear strain caused by the difference in the coefficient of thermal expansion, prolong the life of the mounting structure 10, and to facilitate the routing of the wiring on the mother board side.

FIG. 4 is a view showing a third embodiment of the mounting structure and the mounting method of the present invention, and is a mounting structure 2 showing the third embodiment of the mounting structure and the mounting method of the present embodiment.
0 is a perspective plan view of FIG.

Referring to FIG. 4, the mounting structure 20 has two area array components 22 and 23 mounted on a module substrate 21 by bonding them with solder balls (solder balls for component connection) 24, respectively.
Are mounted on a mother board (not shown) by bonding with solder balls (solder balls for board connection) 25.

The area array components 22 and 23 are mounted on the opposite corners of the module substrate 21 respectively. Solder balls 25 for mounting the module substrate 21 on the mother substrate are mounted on the area array component 22. , 2
3 is arranged outside the region.

As described above, the mounting structure 20 of the present embodiment
The module board 21 which is a printed board on which the area array components 22 and 23 are mounted is mounted on the mother board with the solder balls 24 for connecting a plurality of components arranged in an array. In mounting, the area array components 22, 23 and the solder balls 25 for board connection are arranged so as to be displaced from each other in a vertical positional relationship.

Therefore, even when the mounting structure 20 has a two-stage structure, the degree of freedom of the module substrate 21 on which the area array components 22 and 23 are mounted can be maintained, and the arrangement of the solder balls 25 for connecting the substrates can be reduced. It is possible to simplify the structure, reduce the shear strain due to the difference in the coefficient of thermal expansion, prolong the life of the mounting structure 20, and facilitate the wiring of the mother board. .

FIG. 5 is a view showing a fourth embodiment of the mounting structure and the mounting method according to the present invention. The mounting structure 3 showing the fourth embodiment of the mounting structure and the mounting method according to the present embodiment.
0 is a perspective plan view of FIG.

In FIG. 5, the mounting structure 30 has four area array components 32, 33, 3 on a module board 31.
4 and 35 are bonded and mounted by solder balls (solder balls for component connection) 36, respectively, and the module board 31 is mounted on a mother board (not shown) by bonding with solder balls (solder balls for board connection) 37. Have been.

Area array components 32, 33, 34, 35
Are mounted on the four corners of the quadrangular module board 31, respectively. Solder balls 37 for mounting the module board 31 on the mother board are provided on the area array components 32, 33, 34, 35. It is located outside the area.

As described above, the mounting structure 30 of the present embodiment
Is a method of mounting a module substrate 31 which is a printed board on which four area array components 32 to 35 are mounted with a plurality of component connection solder balls 36 arranged in an array, using a plurality of board connection solder balls 37. When mounting on the board, the area array components 32 to 35 and the solder balls 37
Are displaced from each other in a vertical positional relationship. That is, the area array components 32 to 35 are arranged at the four corners of the module substrate 31 and the solder balls 37 are provided.
Are removed from the area array components 32 to 35 and arranged in a cross shape.

Therefore, even when the mounting structure 30 has a two-stage structure, the degree of freedom of the module substrate 31 on which the area array components 32 to 35 are mounted can be maintained, and the arrangement of the solder balls 37 for connecting the substrates can be reduced. It is possible to simplify the structure, reduce the shear strain due to the difference in the coefficient of thermal expansion, extend the life of the mounting structure 30, and facilitate the wiring of the wiring on the mother board side. .

FIGS. 6 to 9 are views showing a fifth embodiment of the mounting structure and the mounting method of the present invention. In this embodiment, when a module substrate is joined to a mother substrate by soldering, FIG. In addition, a supporting solder ball for supporting a module substrate is provided on a mother substrate, and the supporting solder ball is separated from the module substrate after soldering.

FIG. 6 is a front view of a mother board 41 of a mounting structure 40 to which the fifth embodiment of the mounting structure and the mounting method of the present embodiment is applied. The structure 40 is provided with a solder ball (solder ball for board connection) 43 for joining a module board 42 (see FIG. 7) mounted on the mother board 41 to the center.

That is, an electrode 44 having a predetermined surface area for soldering the module substrate 42 is formed on the mother substrate 41 so as to be brought close to the center of the mother substrate 41. The solder balls 43 are arranged.

On the mother substrate 41, a plurality of supporting electrodes 45 having a surface area larger than the electrodes 44 by a predetermined amount are formed at peripheral positions of the mother substrate 41. On the supporting electrodes 45, supporting solder balls are provided. 46 are arranged. The supporting solder ball 46 has the same size as the solder ball 43 on the electrode 44. Although not shown, an electrode is formed on the module substrate 42 at a position facing the solder ball 43, and an electrode is formed at a position facing the supporting solder ball 46, that is, at a position facing the supporting electrode 45. No electrode is formed.

In this way, the solder balls 43 are arranged on the electrodes 44, and the supporting solder balls 46 are arranged on the supporting electrodes 45. As shown in FIG. The module substrate 42 mounted with the solder balls 48 for connection is mounted, and FIG.
Reflow as shown in FIG.

Upon reflow, the solder balls 43 and the supporting solder balls 46 are melted, and the solder balls 43 connect the electrodes 44 on the mother board 41 with the electrodes of the module substrate 42 formed at positions facing the solder balls 43. The module board 42 can be mounted on the mother board 41 by bonding with the ball 43.

On the other hand, no electrode is formed on the module substrate 42 at a position facing the supporting solder ball 46, and the area of the supporting electrode 45 is larger than that of the electrode 44. , Supporting solder balls 46
As shown in FIG. 8 and FIG. 9, the surface of the support electrode 45 spreads over the entire large surface of the support electrode 45, becomes lower than the solder ball 43 formed on the electrode 44, and separates from the module substrate 42.

Therefore, it is possible to easily and easily form the mounting structure 40 in which the degree of freedom of the module substrate 42 is improved.

As described above, the mounting structure 40 of the present embodiment
A solder ball 46 for supporting a module substrate 42 which is a printed circuit board is arranged on a portion of the mother substrate 41 where the solder ball 43 for substrate connection is not located;
The supporting solder balls 46 are made to wet and spread by being reflowed and separated from the module substrate 42.

Accordingly, the module substrate 42 is tilted at the time of mounting due to the imbalance in the layout of the solder balls 43, so that it is possible to prevent the bonding error between the module substrate 42 and the mother substrate 41 due to the substrate connection solder balls 43, and to reduce the area. The degree of freedom of the module substrate 42 on which the array components 37 are mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced.
2 and the mother substrate 41 can be reliably bonded, and the life can be prolonged.

Further, the mounting structure 40 of the present embodiment is provided at the position where the supporting solder balls 46 of the mother board 41 are arranged.
Electrode 4 for connecting solder ball 43 for substrate connection
The supporting electrode 45 having a surface area larger than the surface area of the supporting electrode 4 is formed. No electrode is formed on the module substrate 42 at a position facing the supporting electrode 45, and the supporting solder balls 46 are formed.
Are arranged on the supporting electrode 45 and are reflowed so that the supporting electrode 45 wets and spreads and is separated from the module substrate 42.

Accordingly, the module substrate 42 is inclined at the time of mounting due to the imbalance of the layout of the solder balls 43, so that the bonding error between the module substrate 42 and the mother substrate 41 due to the substrate connection solder balls 43 can be prevented, and the area can be reduced. The degree of freedom of the module substrate 42 on which the array component 47 is mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced.
2 and the mother substrate 41 can be reliably bonded, and the life can be prolonged.

FIGS. 10 to 13 are views showing a sixth embodiment of the mounting structure and the mounting method of the present invention. In this embodiment, when a module substrate is joined to a mother substrate by soldering, FIG. In addition, a supporting solder ball for supporting the module substrate is provided after forming a through hole in the mother substrate, and after the soldering, the supporting solder ball is spread over the through hole and separated from the module substrate.

FIG. 10 is a front view of a mother board 51 of a mounting structure 50 to which a sixth embodiment of the mounting structure and the mounting method according to the present embodiment is applied. The structure 50 is provided in a state where a solder ball (solder ball for board connection) 53 for joining a module substrate 52 (see FIG. 11) mounted on a mother substrate 51 is brought to the center.

That is, an electrode 54 having a predetermined surface area for soldering the module substrate 52 is formed on the mother substrate 51 so as to be brought close to the center of the mother substrate 51. A solder ball 53 for connecting a substrate is provided.

On the mother substrate 51, a through hole 5 having a protruding portion serving as a mounting portion is provided around the mother substrate 51.
5 are formed, and a supporting solder ball 56 is arranged on the through hole 55. The supporting solder ball 56 has the same size as the solder ball 53 on the electrode 54. Although not shown, electrodes are formed on the module substrate 52 at positions opposed to the solder balls 53, and the module substrate 52 at positions opposed to the supporting solder balls 56, that is, at positions opposed to the through holes 55. No electrodes are formed.

In this manner, the solder balls 53 are arranged on the electrodes 54 and the supporting solder balls 56 are arranged on the through holes 55, and as shown in FIG. Solder balls) 5
8. Mount the module board 52 mounted in 8,
As shown in FIG.

Upon reflow, the solder balls 53 and the supporting solder balls 56 are melted, and the electrodes 54 on the mother board 51 and the electrodes of the module substrate 52 formed at positions facing the solder balls 53 are soldered by the solder balls 53. The module board 52 can be mounted on the mother board 51 by bonding with the balls 53.

On the other hand, no electrodes are formed on the module substrate 52 at positions opposed to the supporting solder balls 56, and the supporting solder balls 56
As shown in FIGS. 12 and 13, most of the molten supporting solder balls 56 are wet-spread in the through-holes 55 and have a height of the electrode 5.
4 is lower than the solder ball 53 formed on
Move away from module substrate 52.

Therefore, it is possible to easily and easily form the mounting structure 50 in which the degree of freedom of the module substrate 52 is improved.

As described above, the mounting structure 50 of the present embodiment
Forms a through-hole 55 at the position where the supporting solder ball 56 is arranged on the mother board 51, and
No electrode is formed on the module substrate 52 at a position facing the substrate, and the supporting solder balls 56 are arranged on the through-holes 55, and are reflowed so as to be wet-spread in the through-holes 55 and separated from the module substrate 52. Let me.

Therefore, the module board 52 is inclined at the time of mounting due to the imbalance of the layout of the solder balls 53, and it is possible to prevent the bonding error between the module board 52 and the mother board 51 by the solder balls 53 for board connection, and to reduce the area. The degree of freedom of the module substrate 52 on which the array components 57 are mounted can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced.
2 and the mother substrate 51 can be reliably joined, and the life can be prolonged.

As described above, the invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

[0087]

According to the mounting structure of the first aspect of the present invention, a plurality of board connecting solders for mounting a printed board on which an area array component is mounted with a plurality of component connecting solder balls on a mother board. Since the balls are arranged close to the center of the printed circuit board, the flexibility of the printed circuit board on which the area array components are mounted can be maintained even when the mounting structure is a two-stage structure, and the thermal expansion coefficient , And the life of the mounting structure can be prolonged.

According to the mounting structure of the second aspect of the present invention,
When mounting a printed circuit board on which an area array component is mounted with a plurality of solder balls for connecting parts in an array on a mother board with a plurality of solder balls for connecting the board, the area array component and the solder for connecting the board are mounted. Since the balls are arranged so as to be displaced from each other in the vertical positional relationship, the flexibility of the printed circuit board on which the area array components are mounted can be maintained even when the mounting structure is a two-stage structure. , Which can simplify the arrangement of the solder balls for board connection, reduce the shear strain due to the difference in thermal expansion coefficient, prolong the service life, and facilitate the wiring of the wiring on the mother board side. It can be.

According to the mounting structure of the third aspect of the present invention,
Since the supporting solder balls that support the printed circuit board are placed on the part of the mother board where the solder balls for connecting the board are not located, and the supporting solder balls are reflowed, they are spread and spread away from the printed circuit board. The printed circuit board tilts during mounting due to the imbalance in the layout of the solder balls. This prevents solder balls for connection between the printed circuit board and the mother board from being mistaken, and frees the module board on which the area array components are mounted. While maintaining the degree, the shear strain due to the difference in the coefficient of thermal expansion can be reduced, and the bonding between the printed board and the mother board can be surely performed, and the life can be prolonged.

According to the mounting structure of the invention described in claim 4,
A support electrode having a surface area larger than the surface area of the electrode for connecting the board connection solder ball is formed at the position of the support solder ball on the mother board, and the printed circuit board at a position facing the support electrode is formed on the printed circuit board. The electrodes are not formed, and the solder balls for support are placed on the support electrodes and reflowed to wet the support electrodes and spread away from the printed circuit board. Sometimes the printed circuit board tilts, preventing soldering errors between the printed circuit board and the mother board due to the solder balls for connecting the boards, and maintaining the degree of freedom of the module board on which the area array components are mounted, and the difference in thermal expansion coefficient. Shear strain can be reduced, and the printed circuit board and mother board can be securely joined, and the service life can be extended. Can Kusuru.

According to the mounting structure of the invention described in claim 5,
A through hole is formed at the position where the supporting solder ball of the mother board is arranged, and no electrode is formed on the printed board at a position facing the supporting electrode, and the supporting solder ball is disposed on the through hole, Since the reflow causes the printed circuit board to wet and spread inside the through hole and separate from the printed circuit board, the printed circuit board tilts during mounting due to the imbalance of the solder ball layout, and the printed circuit board and the mother board due to the solder balls for board connection In addition to preventing joining errors, the degree of freedom of the module board on which the area array component is mounted can be kept low, the shear strain due to the difference in thermal expansion coefficient can be reduced, and the printed board and mother board can be joined. And the service life can be prolonged.

According to the mounting method of the invention described in claim 6,
Since a plurality of board connection solder balls for mounting the printed circuit board on which the area array components are mounted on the mother board with a plurality of component connection solder balls are arranged near the center of the printed circuit board, Even when the mounting structure is a two-stage structure, the degree of freedom of the module substrate on which the area array component is mounted can be maintained, the shear strain due to the difference in thermal expansion coefficient can be reduced, and the life can be prolonged.

According to the mounting method of the invention described in claim 7,
When mounting a printed circuit board on which an area array component is mounted with a plurality of solder balls for connecting parts in an array on a mother board with a plurality of solder balls for connecting the board, the area array component and the solder for connecting the board are mounted. Since the balls are arranged so as to be displaced from each other in a vertical positional relationship, even when the mounting structure is a two-stage structure, the degree of freedom of the module substrate on which the area array components are mounted can be maintained. The arrangement of the solder balls for connecting the boards can be simplified, the shear strain due to the difference in the coefficient of thermal expansion can be reduced, the service life can be extended, and the wiring on the mother board side can be easily arranged. It can be.

According to the mounting method of the present invention, the supporting solder balls for supporting the printed circuit board are arranged on the portions of the mother board where the board connecting solder balls are not located, and the supporting solder balls are reflowed. This prevents the printed circuit board from tilting during mounting due to the imbalance in the layout of the solder balls, and prevents the printed circuit board and mother board from being bonded incorrectly due to the solder balls for board connection. While maintaining the degree of freedom of the module board on which the area array components are mounted, it is possible to reduce the shear strain due to the difference in the coefficient of thermal expansion, and it is possible to securely join the printed board and the mother board. , The service life can be extended.

According to the mounting method of the ninth aspect, the supporting electrode having a surface area larger than the surface area of the electrode for connecting the board connecting solder ball is formed at the position where the supporting solder ball of the mother board is arranged. No electrode is formed on the printed circuit board at a position opposed to the supporting electrode, and the supporting solder balls are arranged on the supporting electrode and reflowed, so that the supporting electrode wets and spreads and separates from the printed circuit board. Since the printed circuit board is tilted during mounting due to the imbalance in the layout of the solder balls, it is possible to prevent bonding errors between the printed circuit board and the mother board due to the solder balls for connecting the boards, and to mount area array components. The flexibility of the module board can be maintained, and the shear strain due to the difference in thermal expansion coefficient can be reduced. It is possible to reliably perform bonding, it is possible to prolong the life.

According to the mounting method of the present invention, a through-hole is formed at the position where the supporting solder ball of the mother board is arranged, and no electrode is formed on the printed board at a position opposed to the through-hole. The solder balls are placed on the through-holes and reflowed so that they spread out in the through-holes and separate from the printed circuit board. It is possible to prevent the bonding error between the printed board and the mother board due to the solder balls for connection, and to maintain the flexibility of the module board on which the area array components are mounted, and to reduce the shear strain due to the difference in the coefficient of thermal expansion. It is possible to securely connect the printed board and mother board and extend the life. Kill.

[Brief description of the drawings]

FIG. 1 is an enlarged front view of a main part of a mounting structure to which a first embodiment of a mounting structure and a mounting method according to the present invention is applied.

FIG. 2 is a partially transparent plan view of a module substrate having the mounting structure of FIG. 1;

FIG. 3 is a partial perspective plan view of a module substrate having a mounting structure to which a second embodiment of the mounting structure and the mounting method of the present invention is applied.

FIG. 4 is a partially transparent plan view of a module substrate having a mounting structure to which a third embodiment of the mounting structure and the mounting method of the present invention is applied.

FIG. 5 is a partially transparent plan view of a module substrate having a mounting structure to which a fourth embodiment of the mounting structure and the mounting method of the present invention is applied.

FIG. 6 is a front view of a mother board having a mounting structure to which a fifth embodiment of the mounting structure and the mounting method according to the present invention is applied;

7 is a front view showing a state where a module substrate is arranged on the mother substrate of FIG. 6 via solder balls and supporting solder balls.

FIG. 8 is a front view showing a state where the mother board and the module board of FIG. 7 are being reflowed;

FIG. 9 is a front view of the mother board and the module board after the reflow of FIG. 8;

FIG. 10 is a front partial cross-sectional view of a mother board having a mounting structure to which a sixth embodiment of the mounting structure and the mounting method of the present invention is applied.

11 is a partial front sectional view showing a state where a module substrate is arranged on the mother substrate of FIG. 10 via solder balls and supporting solder balls.

FIG. 12 is a front partial sectional view showing a state where the mother board and the module board of FIG. 11 are being reflowed;

FIG. 13 is a front partial cross-sectional view of the mother board and the module board after the reflow of FIG.

FIG. 14 is a front view of a mother board and a module board having a conventional mounting structure.

FIG. 15 is a front view showing a state where the module board having the conventional mounting structure of FIG. 14 is warped.

FIG. 16 is a front view showing a state in which the degree of freedom of the module substrate is restricted in the conventional mounting structure of FIG. 14;

17 is a plan view showing a state in which the degree of freedom of the module substrate is restricted in the conventional mounting structure of FIG.

[Description of Signs] 1 Mounting structure 2 Mother substrate 3 Solder ball 4 Module substrate 5 Solder ball 6 Area array component 7 Semiconductor package 10 Mounting structure 11 Module substrate 12 Area array component 13, 14 Solder ball 20 Mounting structure 21 Module substrate 22, 23 Area Array Components 24, 25 Solder Ball 30 Mounting Structure 31 Module Board 32 to 35 Area Array Components 36, 37 Solder Ball 40 Mounting Structure 41 Mother Board 42 Module Board 43 Solder Ball 44 Electrode 45 Supporting Electrode 46 Supporting Solder Ball 47 Area array component 50 Mounting structure 51 Mother substrate 52 Module substrate 53 Solder ball 54 Electrode 55 Through hole 56 Supporting solder ball 57 Area array component 58 Solder ball

Claims (10)

[Claims] 1. A mounting structure in which a printed board on which an area array component is mounted by a plurality of component connecting solder balls arranged in an array is mounted on a mother board by a plurality of board connecting solder balls. The mounting structure, wherein the board connection solder balls are arranged near the center of the printed board. 2. A mounting structure in which a printed board on which an area array component is mounted with a plurality of component connecting solder balls arranged in an array is mounted on a mother board with a plurality of board connecting solder balls. The mounting structure, wherein the area array component and the solder ball for board connection are arranged so as to be displaced from each other in a vertical positional relationship. 3. The mother board is provided with a supporting solder ball for supporting the printed board at a portion where the board connecting solder ball is not located, and the supporting solder ball is reflowed. Spread wet with
The mounting structure according to claim 1, wherein the mounting structure is separated from the printed circuit board. 4. A support electrode having a surface area larger than a surface area of an electrode for connecting the solder ball for substrate connection is formed at a position where the solder ball for support is arranged on the mother substrate. No electrodes are formed on the printed circuit board at a position facing the electrodes for support, and the solder balls for support are spread on the support electrodes by being arranged on the support electrodes and being reflowed, 4. The mounting structure according to claim 3, wherein the mounting structure is separated from the printed circuit board. 5. The mother board has a through hole formed at a position where the supporting solder ball is disposed, and no electrode is formed on the printed circuit board at a position facing the through hole. 4. The mounting structure according to claim 3, wherein the solder balls are arranged on the through holes and reflowed, so that the solder balls spread out in the through holes and are separated from the printed circuit board. 5. 6. A mounting method for mounting a printed board on which an area array component is mounted with a plurality of component connection solder balls arranged in an array on a mother board with a plurality of board connection solder balls. A mounting method, wherein a solder ball for connection is arranged near a central portion of the printed circuit board. 7. A mounting method for mounting a printed circuit board on which an area array component is mounted with a plurality of component connection solder balls arranged in an array on a mother board with a plurality of substrate connection solder balls. A mounting method, wherein an array component and the solder ball for board connection are arranged so as to be displaced from each other in a vertical positional relationship. 8. The mounting method according to claim 1, further comprising: disposing a supporting solder ball for supporting the printed board on a portion of the mother board where the board connecting solder ball is not located, and reflowing the supporting solder ball. The mounting method according to claim 6, wherein the mounting is performed so as to be spread and wet and separated from the printed circuit board. 9. The mounting method according to claim 1, wherein a supporting electrode having a surface area larger than a surface area of an electrode for connecting the substrate connecting solder ball is formed at the position of the supporting solder ball on the mother substrate. An electrode is not formed on the printed circuit board at a position facing the supporting electrode, the supporting solder ball is disposed on the supporting electrode, and the supporting solder ball is reflowed to support the supporting solder ball. The mounting method according to claim 8, wherein the mounting electrode is wetted and spread and is separated from the printed circuit board. 10. The mounting method according to claim 1, wherein a through-hole is formed at a position where the supporting solder ball is arranged on the mother board, and no electrode is formed on the printed board at a position facing the through-hole. 9. The solder ball according to claim 8, wherein the solder ball for support is arranged on the through hole, and the solder ball for support is reflowed so as to be spread in the through hole and separated from the printed circuit board. Implementation method.