JP2002016184A - Thermal deformation preventing structure of bga package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal deformation preventing structure of a BGA package wherein, related to connection between the BGA package and a printed board, cracking at a soldered connection is prevented which is caused by thermal deformation of a BGA main body and the printed board which can occur after passing through a reflow furnace for mounting the BGA package. SOLUTION: The thermal deformation preventing structure of the BGA package is provided which comprises a beam member 3 for covering the entire surface of a BGA main body 1 when the BGA package is mounted on a printed board 5, a pin member 2 which is buried in the BGA main body 1 and protrudes above a bottom surface, and a through hole 6 through which, the pin member 2 of the BGA package penetrates and which is formed at the printed board from a material of melting point about 1000 deg.C or above. The beam member 3 of the BGA package may be arranged in lattice while the through hole 6 of the printed board 5 may be formed by copper plating or gold plating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing thermal deformation of a BGA (ball grid array) package, and more particularly to a structure for preventing thermal deformation that may occur when soldering a BGA package to a printed circuit board. Regarding the structure.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Application Publication No. 11-19567
No. 8 discloses a surface mount module mounting structure for the purpose of reducing the manufacturing cost and improving the reliability of the device.

In this surface mounting module mounting structure, solder bumps are provided in a region near the periphery of the lower surface of a substrate on which semiconductor components are mounted, and pins of a press-fit pin structure are fixed to a portion from the center. In the printed circuit board, pads are formed in a region near the periphery of the region where the surface module is mounted, and a plurality of through holes are formed in an inner region. Furthermore, the surface module is mounted with solder bumps soldered to pads and press-fit pins pressed into the through holes.

On the other hand, in a semiconductor integrated circuit disclosed in Japanese Patent Application Laid-Open No. 10-98073, a lead portion of a wiring formed on a wiring board is electrically connected to an external terminal on a main surface of a semiconductor chip. A semiconductor integrated circuit in which a land portion of a wiring formed on a substrate is electrically connected to a bump electrode, wherein external terminals of the semiconductor chip are arranged in a peripheral portion of the semiconductor chip, and external terminals of the semiconductor chip include Are connected via the wiring formed on the wiring board. The bump electrodes are arranged in two rows around the outer region from the outer periphery of the semiconductor chip, and the reinforcing member is arranged on the back surface of the wiring board at a portion extending from the vicinity of the outer periphery to the periphery of the semiconductor chip.

[0005]

However, the above-mentioned conventional semiconductor integrated circuit or the like has a structure in which only the solder connection is performed by the solder balls arranged on the lower surface of the BGA main body, and the heat of the BGA main body and the printed circuit board is reduced. Since no measures have been taken to prevent the solder joints from being broken due to thermal deformation in consideration of the coefficient of expansion, cracks in the solder ball portions due to thermal deformation of the BGA body during reflow cannot be prevented.

Accordingly, the present invention has been made in view of the above-mentioned problems in the conventional semiconductor integrated circuit and the like.
In the connection between the BGA package and the printed circuit board, B
To provide a BGA package thermal deformation prevention structure capable of preventing cracks in a solder connection portion due to thermal deformation of a BGA main body and a printed circuit board which may occur after passing through a reflow furnace for mounting a GA package. With the goal.

[0007]

According to one aspect of the present invention, there is provided a structure for preventing thermal deformation when a BGA package is mounted on a printed circuit board.
A beam member covering the entire surface of the main body, a pin member embedded in the BGA main body and protruding from the bottom surface, and a printed board made of a material through which the pin member of the BGA package can penetrate and has a melting point of approximately 1000 ° C. or higher And a through-hole formed in the hole.

According to the first aspect of the present invention, the BGA package is mounted on the printed circuit board by pressing before the reflow, and the beam member covering the surface of the BGA package reduces the thermal deformation at the time of the reflow and reduces the pin size. The member holds the printed circuit board by friction, forcibly synchronizes the deformation of the printed circuit board with the deformation of the BGA package,
By keeping the height interval between the BGA package and the printed circuit board constant and preventing the destruction of the connection between the pin member and the through hole due to thermal deformation, it is possible to reduce the thermal stress applied to the solder ball solder connection part, This prevents cracks in the solder ball portion, thereby improving the connection reliability of the BGA package with the printed circuit board and extending the life of the product.

At this time, since the through holes are formed on the printed circuit board with a material having a melting point of about 1000 ° C. or more,
Unlike the conventional solder plating, the printed circuit board can be reliably held by the pin member without melting the solder at the time of reflow and losing the fixing effect by the pin member.

[0010] The invention according to claim 2 is a method according to claim 1, wherein
In a preferred embodiment of the thermal deformation preventing structure of the GA package, the beam members of the BGA package are arranged in a lattice.

[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
In a preferred embodiment of the thermal deformation preventing structure of the BGA package described above, the through hole of the printed circuit board is formed by copper plating or gold plating which is currently used.

[0012]

Next, a specific example of an embodiment of a thermal deformation preventing structure for a BGA package according to the present invention will be described with reference to the drawings.

The present invention relates to a thermal deformation preventing structure for mounting a BGA package on a printed circuit board. FIGS. 1 and 2 show an embodiment of a BGA package to which the thermal deformation preventing structure is applied.

The BGA package includes a lattice-shaped beam member 3 that covers the entire surface of the BGA main body 1 and a pin member 2 that is embedded in the BGA main body 1 and protrudes from the bottom surface of the BGA main body 1.

The pin member 2 is fixed to the BGA main body 1 so as to be embedded in the BGA main body 1. This pin member 2
Are arranged from the center of the BGA main body 1 and on an extension line from the center. Further, solder balls 4 are provided on the bottom surface of the BGA main body 1 in order to obtain electrical connection.

On the other hand, as shown in FIG.
Is provided with a through hole 6 into which the pin member 2 is press-fitted. As a material for forming the through hole 6, plating other than solder plating, that is, copper plating or gold plating is used. The reason why the material forming the through hole 6 is a plating other than the solder plating is that in the solder plating finish used in the conventional through hole, the solder plating is melted at the time of reflow, and the pin member 2 having the press-fit structure can be fixed. Gone, pin member 2
This is to prevent the mechanical deformation preventing structure from being used.

Next, the operation of the structure for preventing thermal deformation of the BGA package having the above configuration will be described with reference to FIG.

The BGA main body 1 is mechanically fixed by pressing a pin member 2 into a through hole 6 by pressing a printed circuit board 5. At this time, the BGA body 1 mechanically fixed is aligned with the foot pattern 7 of the printed circuit board 5. Thereafter, by passing the fixed BGA main body 1 and the printed board 5 through a reflow furnace, the solder balls 4 are melted and solder-connected to the foot patterns 7 to obtain electrical connection.

Here, the BGA body 1 and the printed board 5 having a mechanical connection structure undergo thermal deformation during reflow. However, the connection between the pin member 2 and the printed board 5 forces the BGA body 1 or the printed board 5. The deformation can be synchronized to the one of the printed circuit boards 5 on the side where the degree of deformation is strong. At this time, as a function of reducing the degree of deformation of the BGA main body 1, a lattice-shaped beam member 3 is added to the entire surface of the BGA to reduce the amount of deformation in the deformation direction. In addition to the mechanical connection using No. 2, it is characterized in that a structure for preventing connection portion breakage due to double thermal deformation is formed.

In the above embodiment, the BGA body 1
Although the beam member 3 that covers the entire surface is formed in a lattice shape, it is sufficient if the beam member 3 functions as a beam member as in the case where a punched hole is formed in one metal plate, even if it is not lattice-shaped.

In the above embodiment, the through-hole 6 of the printed circuit board 5 is formed by copper plating or gold plating. However, the through-hole 6 may be formed of another material having a melting point of about 1000 ° C. or higher which does not melt during reflow. .

[0022]

As described above, according to the present invention,
Thermal deformation of the BGA package that can prevent cracks in the solder connection part due to thermal deformation of the BGA body and the printed circuit board that may occur after passing through the reflow furnace when connecting the BGA package and the printed circuit board A prevention structure can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a structure for preventing thermal deformation of a BGA package according to the present invention, wherein (a) is a plan view,
(B) is a sectional view taken along line AA of (a).

FIG. 2 is a bottom view of the thermal deformation preventing structure of the BGA package of FIG. 1;

FIG. 3 is a cross-sectional view showing a state in which the BGA package having the thermal deformation preventing structure of FIG. 1 is mounted on a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 BGA main body 2 Pin member 3 Beam member 4 Solder ball 5 Printed circuit board 6 Through hole 7 Foot pattern

Claims (3)

[Claims] 1. A structure for preventing thermal deformation when a BGA package is mounted on a printed circuit board, comprising: a beam member covering the entire surface of the BGA body; a pin member embedded in the BGA body and protruding from a bottom surface; A BG through which the pin member of the BGA package is penetrable and which is formed of a material having a melting point of approximately 1000 ° C. or higher on a printed circuit board
A package thermal deformation prevention structure. 2. The beam member of the BGA package,
2. The structure for preventing thermal deformation of a BGA package according to claim 1, wherein the structure is arranged in a lattice. 3. The structure for preventing thermal deformation of a BGA package according to claim 1, wherein said through-hole of said printed board is formed by copper plating or gold plating.