JPH0845982A - Semiconductor device mounting structure and method - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the quality by eliminating the warp of the MCM substrate and the mother board and the connection failure caused by the variation in the height of the BGA ball when the MCM is solder-melt bonded to the mother board by BGA. And [Structure] The LSI 1 and other electronic components are mounted on the surface of the MCM substrate 2. On the back surface of the substrate 2 on which these components are mounted, a conductor pad 3 and a solder ball for connection are formed thereon. And pad 7
Is supplied with an amount of solder that is as high as the solder ball formed on the pad 3. The pad 9 on the substrate 6 side has a larger area than the pad 7. The substrate 2 is mounted on the substrate 6 at a predetermined position and reflow heated to obtain a structure of solder fusion connection between the MCM substrate 2 and the substrate 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device mounting structure and method, and more particularly to a multi-chip module (MC).
The present invention relates to a mounting structure and method for solder-melt connection between substrates with a ball grid array (BGA) using solder balls such as M).

[0002]

2. Description of the Related Art FIG. 3A shows a sectional view of a conventional MCM. This MCM has a BGA connection pad 3 on the back surface of an MCM substrate 2 on the front surface of which an LSI 1 and other electronic components are mounted.
Solder balls 12 are formed on the top. FIG. 3 (B)
3A is mounted on the wiring board 6 and then the solder balls 12 are reflow-heated together with the other electronic components mounted on the board 6 so that the solder connection portion 4 can be formed.
Adheres to the BGA connection pad 3 and the pad 5 on the substrate 6 to complete the solder fusion connection. As a mounting structure of a semiconductor device using such a BGA, there are USP 5241133 and USP 5216278.

When the BGA having such a structure is connected to the wiring board, warpage of the MCM board 2 and the wiring board 6 and BG
Due to variations in the height of the solder balls 12 formed on the A pads 3, there are places where the solder balls 12 are not connected to the pads 5 on the wiring board 6 side. Further, the solder connection portion 4 has a solder shape shown in FIG.
As shown in (B), the central portion is a bulged sphere, and the portion joined to the pad 3 on the MCM substrate 2 side and the pad 5 on the wiring substrate 6 side is constricted and the cross-sectional area is the smallest. It becomes a part. For this reason, when thermal strain occurs, stress concentrates on the constricted portion of the solder joint portion 4, causing a fatigue fracture.

In order to solve this problem, as shown in FIG. 4, the solder connecting portion 14 has a structure in which it is stretched into a drum shape or a column shape. As a method for obtaining the connecting portion 14 as shown in FIG. 4, there is one described in, for example, JP-A-57-118650, which is shown in FIG. This is a method for forming solder bumps on the silicon chip 11 and connecting them to the wiring board 6. In this method, solder bumps are formed in advance around the chip 11 and the solder bumps are formed on the wiring board 6. After being temporarily attached to No. 5, the solder is melted by putting them in a heating furnace and heating them to fuse the solder to the pads 5 on the substrate 6, and then when the solder is melted, a vacuum chuck type tool Using 10, the chip 11 is lifted so that the shape of the solder connection portion 14 is cylindrical. By cooling the solder in this state, the connection portion 14 having a desired shape is obtained. When such a construction method is used in the case of MCM, the MC to be adsorbed by the tool 10
Since the components are mounted on the surface of the M substrate, there is a drawback that the tool has to be processed into a shape that does not hit these components.

Another method for obtaining the connecting portion 14 as shown in FIG. 4 is disclosed in Japanese Patent Laid-Open No. 163852/55, which is shown in FIG. This is chip 1
1 is a solder connection portion 1 connected to the pad 5 of the wiring board 6
7 is provided with a pad 3 on which a solder bump to be formed is formed, and a pad 16 having a size different from that of the pad 3,
Solder bumps 18 different from those of the solder connection portion 17 are formed. When connecting the two substrates 11 and 6, the bumps and 18 to be the solder connecting portions 17 are melted and the pads 3 and 5 are connected by the solder connecting portions 17. At this time, since the solder amount of the solder bump 18 is larger than that of the solder connection portion 17, the surface tension of the solder bump 18 widens the space between the substrates 11 and 6. In this way, the shape of the solder connection part 17 of FIG. 6 is obtained, and the connection failure due to the bulge of the connection part is prevented. However, according to this method, when the tips of the solder bumps and the pads on the board are not in contact with each other due to the warp of the boards 11 and 6 and the variation in the height of the solder bumps (or solder balls), unconnected defects are said to occur. There are drawbacks.

[0006]

In any of the above-described conventional semiconductor device mounting structures and methods, warpage of the substrate,
There are problems that it is difficult to reduce connection failure caused by non-contact between the solder connection portion and the pad due to variations in the height of the solder balls, and it is difficult to obtain highly reliable solder connection.

[0007]

A semiconductor device connection structure according to the present invention comprises a first substrate, a second substrate, a first pad provided on the first substrate, and the second substrate. A solder connection portion formed of a solder ball fused and connected to a second pad provided on the first substrate, and a first solder provided on the first substrate.
And a board-interval-controlling solder connection portion, which is provided on the second board and has a larger area than the first board-interval control pad, and is fused and connected to the second board-interval control pad. The second substrate may be provided with a projection with which the first substrate abuts.

According to the method of connecting a semiconductor device of the present invention, a solder ball is formed on a first pad provided on a first substrate, and a first substrate gap control pad provided on the first substrate. Substrate soldering control solder having the same height as the solder balls is supplied to the second pad provided on the second substrate and the first substrate spacing control pad to the second pad. The first board is mounted on the second board by aligning with the second board spacing control pad which is provided on the board and has a larger area than the first board spacing control pad. Each of the substrate spacing control solders is reflow-heated to be melted and connected to the corresponding second pad and second substrate spacing control pad.

[0009]

When the first and second substrates are connected using the solder balls, the solder balls are provided on the first substrate separately from the original solder balls for the purpose of conduction between the circuits of the first and second substrates. Solder is supplied to the first board gap control pad,
The second substrate has a second
The pad for controlling the substrate spacing is arranged. When these two substrates are combined and reflow heated, the solder supplied to the first substrate gap control pad melts and wets and spreads on the pad having a large area. At this time, since both boards are attracted,
The warp of the board and the variation of the height of the solder balls are absorbed to eliminate the occurrence of the connection failure due to the non-contact between the solder balls and the pads, and the solder spread on the second board gap control pad spreads in a fillet shape. Since the connection portion is formed, the connection strength is increased. This will increase the reliability of the connection.

[0010]

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

FIG. 1A is a sectional view showing a solder melting connection structure of a semiconductor device according to a first embodiment of the present invention. This embodiment will be described according to the manufacturing process.
The LSI 1 is bonded to the substrate 2 face down or face up. Still other electronic components (eg chip resistors, chip capacitors, etc.)
Is also installed. Conductor pads 3 are provided on the back surface of the substrate 2 on which these components are mounted, and solder balls for connection are formed thereon. Further, a pad 7 is provided on the back surface of the substrate 2, and the pad 7 is provided on the pad 7.
The amount of solder supplied is the same as the height of the solder balls formed above.

The board 2 is mounted on the board 6 at a predetermined position, and by reflow heating, the solder ball on the pad 3 is fixed to the pad 5 on the board 6 to form the solder connection portion 4, and the solder on the pad 7 is soldered. Is fixed to the pad 9 on the substrate 6 to become the solder connection portion 8 for controlling the substrate gap, and FIG.
The connection structure shown in is formed. Here, the pad 7 and the pad 9 may have a circular shape, a square shape, or another shape, but the area of the pad 9 is larger than that of the pad 7.
When the solder on the pad 7 is heated and spreads wet and spreads on the pad 9, the substrates 2 and 6 are attracted to each other, so that all the solder connecting portions 4 are reliably connected to the pad 5 and a highly reliable solder can be obtained without increasing the number of working steps. The connection was obtained, and the yield in connecting the semiconductor devices was improved.

FIG. 1B is a sectional view of the second embodiment of the present invention. Since the main constituent elements are the same as those in the first embodiment, their explanations are omitted here and only the differences are extended. Board 6
An insulating (for example, solder resist) protrusion 15 having a predetermined height is previously formed on the substrate 2. The substrate 2 has the same configuration as that of the first embodiment. The substrate 2 is mounted on the substrate 6 at a predetermined position. Reflow heat. At this time, the board 2 and the board 6 are attracted to each other by the solder on the pad 7, and the distance between the boards 2 and 6 is narrowed until the board 2 comes into contact with the projections 15. Finally, the height interval of the projections 15 is secured between them. .

FIG. 2A is a sectional view of the third embodiment of the present invention. The main constituent elements are the same as in the first embodiment, and the difference is that in the first embodiment, the pads 7 and 9 and the solder connection portion 8 for controlling the substrate spacing are provided only at one location. In the third embodiment, the substrates 2, which are arranged at a plurality of locations,
6 are connected. As a result, the two substrates 2 and 6 are
It is possible to deal with boards with large warpage and solder balls with large height variations compared to the above example, and such boards and solder balls can be purchased at low cost, further reducing the price. Can be achieved.

FIG. 2B shows a fourth embodiment of the present invention. Main constituent elements are common to the first to third embodiments. The difference from these is that electronic components such as the LSI 1 are mounted on the back surface of the substrate 2 as well as the front surface at a high density.

[0016]

As described above, the present invention has a larger area than the first substrate spacing control pad provided on the first substrate and the first substrate spacing control pad provided on the second substrate. By melt-connecting the solder connection portion for controlling the board space to the second board space control pad, the first board and the second board are attracted to each other by utilizing the wetting at the time of the solder fusion joining, and By making it narrower, we can reduce the connection failure caused by the warp of the board and the non-contact between the solder ball and the pad due to the variation of the height of the solder ball, and the highly reliable solder connection and the improvement of the yield without increasing the man-hours. There is an effect that can be achieved. Furthermore, since the board-spacing-controlling solder connection section forms a fillet-shaped connection section on the second pad, the connection strength between the first and second boards is increased, which also improves reliability.

[Brief description of drawings]

FIG. 1A is a sectional view of a first embodiment of the present invention, and FIG. 1B is a sectional view of a second embodiment of the present invention.

FIG. 2A is a sectional view of a third embodiment of the present invention, and FIG. 2B is a sectional view of a fourth embodiment of the present invention.

FIG. 3A is a sectional view of an MCM used in a conventional semiconductor device connection structure, and FIG. 3B is a sectional view of a conventional semiconductor device connection structure.

FIG. 4 is a cross-sectional view of another conventional semiconductor device mounting structure.

FIG. 5 is a cross-sectional view showing the manufacturing process of the conventional semiconductor device mounting structure shown in FIG. 4;

FIG. 6 is a sectional view of a mounting structure of still another conventional semiconductor device.

[Explanation of symbols]

 1 LSI 2,6 Board 3,5,7,9,16 Pad 4,14 Solder Connection Section 8 Board Spacing Control Solder Connection Section 10 Tool 11 Chip 12 Solder Ball 15 Protrusion 17,18 Solder Bump

Claims (5)

[Claims] 1. A first substrate, a second substrate, and the first substrate.
A first pad provided on the first substrate and a first pad provided on the first substrate, and a solder connection portion including a solder ball melt-connected to a first pad provided on the second substrate and a second pad provided on the second substrate. A board space control pad, and a board space control solder connection portion fused to a second board space control pad provided on the second board and having a larger area than the first board space control pad. A semiconductor device mounting structure characterized by the above. 2. The mounting structure for a semiconductor device according to claim 1, wherein a protrusion with which the first substrate contacts is provided on the second substrate. 3. The mounting structure for a semiconductor device according to claim 1, wherein a plurality of sets of a first board space control pad, a second board space control pad and a board space control solder connection portion are provided. 4. The semiconductor device according to claim 1, 2 or 3, wherein an electrical component is mounted on a surface of the first substrate or the second substrate between the first substrate and the second substrate. Mounting structure. 5. A solder ball is formed on a first pad provided on a first substrate, and the same height as the solder ball is formed on a first substrate gap control pad provided on the first substrate. The substrate spacing control solder is supplied, the first pad is provided on the second substrate on the second pad, and the first substrate spacing control pad is provided on the second substrate. The first board is mounted on the second board in alignment with a second board spacing control pad having a larger area than that of the board spacing control pad, and the solder balls and the board spacing controlling solder are respectively attached. A method of mounting a semiconductor device, characterized by performing reflow heating and melting and connecting to the corresponding second pad and the second substrate gap control pad.