JPH1050877A - Semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor package in which reliability of mechanical and electrical connection can be improved by dispersing and absorbing occurring thermal stress. SOLUTION: A BGA type semiconductor package has a rectangular tape carrier 10. A number of soldering balls 16 are provided on the under face of the tape carrier and a semiconductor chip 18 is mounted on the top face. A rectangular stiffener sticks on the top face of the tape carrier so as to surround the semiconductor chip. Further, a rectangular cover plate 30 sticks on the top face of the stiffener and on the top face of the semiconductor chip. A plurality of slits 26 for absorbing and dispersing thermal stress occurring owing to changes in temperature are opened in corner parts of the stiffener.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package such as a ball grid array type and a pin grid array type, and more particularly to a semiconductor package using a tape carrier package.

[0002]

2. Description of the Related Art In recent years, ball grid array type (hereinafter referred to as BGA type) and pin grid array (hereinafter referred to as PGA type) semiconductor packages have been widely used as semiconductor devices in electronic equipment. As these semiconductor packages, for example, those using a tape carrier package (hereinafter, referred to as TCP) on which a semiconductor chip is mounted are known.

For example, a BGA type semiconductor package of this type is soldered to a rectangular tape carrier, a semiconductor chip mounted on one surface of the tape carrier, and an electrode formed on the other surface of the tape carrier. And a large number of solder balls. Then, on the one surface of the tape carrier, a metal stiffener, that is, a reinforcing plate is adhered and fixed so as to surround the semiconductor chip in order to maintain the flatness of the tape carrier, and further, on this stiffener, A cover for heat dissipation and protection is adhered and fixed in contact with the upper surface of the semiconductor chip.

[0004] The BGA type semiconductor package thus configured is mounted on a printed circuit board by soldering solder balls to pads on the printed circuit board. Such a BGA type semiconductor package is capable of disposing solder balls functioning as electrodes over the entire bottom surface of the tape carrier, such as a pin grid array type having a large number of lead terminals derived from side edges of the resin package. As compared with the semiconductor package of (1), there is an advantage that the electrode interval can be set wider and the mounting density can be improved.

[0005]

However, the above-mentioned BGA type semiconductor package is constituted by laminating, for example, a tape carrier made of polyimide, a stiffener made of stainless steel or the like, and a cover made of copper or the like. That is, the BGA type semiconductor package is formed by laminating members made of different kinds of materials, and these members also have different coefficients of thermal expansion. Further, a BGA type semiconductor package is mounted on a printed circuit board made of a different material.

Therefore, when a temperature change occurs in the semiconductor package due to turning on / off of a power supply, a tape carrier,
The stiffener and the cover thermally expand by different amounts, and the semiconductor package and the printed circuit board also differ in the amount of thermal expansion. As a result, thermal stress is generated in the semiconductor package, and a load acts on the connection portion of the solder ball. Then, due to this load, there is a possibility that the connection portion of the solder ball is peeled off or a crack is generated in the solder ball. Therefore, the BGA type semiconductor package has a problem that reliability is deteriorated in long-term use.

The present invention has been made in view of the above points, and has as its object to disperse and absorb the generated thermal stress, thereby improving the reliability of mechanical and electrical connections. To provide a package.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor package according to the present invention, comprising a tape carrier having a conductor pattern, and a tape carrier provided on one surface of the tape carrier. A plurality of conducting electrodes, a semiconductor chip mounted on the other surface of the tape carrier and connected to the conductor pattern, and a reinforcing plate fixed on the other surface of the tape carrier so as to surround the semiconductor chip. A cover plate fixed on the reinforcement in contact with the semiconductor chip, wherein the reinforcement plate has a plurality of slits or holes for absorbing and diffusing thermal stress generated due to a temperature change. It is characterized by being formed.

According to the semiconductor package of the present invention, the tape carrier, the reinforcing plate, and the cover plate are formed in a rectangular shape having substantially equal dimensions, and the slits or holes are formed in the reinforcing plate. It is characterized in that it is formed at a corner.

According to the semiconductor package having the above configuration, for example, when the semiconductor chip generates heat during operation, the tape carrier, the reinforcing plate, and the cover thermally expand by different amounts from each other, and as a result, thermal stress is generated in the semiconductor package.
However, the generated thermal stress is absorbed and diffused by slits or holes formed in the reinforcing plate.

Therefore, the deformation of the semiconductor package due to the thermal stress, the peeling of the solder ball connecting portion, the occurrence of cracks, and the like are prevented. Further, by providing slits or holes in the reinforcing plate, it is possible to reduce the weight of the entire semiconductor package.

According to a third aspect of the present invention, there is provided a semiconductor package comprising: a tape carrier having a conductor pattern;
A plurality of electrodes provided on one surface of the tape carrier and electrically connected to the conductor pattern, a semiconductor chip mounted on the other surface of the tape carrier and connected to the conductor pattern, and surrounding the semiconductor chip. A reinforcing plate fixed on the other surface of the tape carrier to maintain the flatness of the tape carrier, and a cover plate fixed on the reinforcing plate in contact with the semiconductor chip; The plate is formed in a lattice shape, and is characterized by absorbing and diffusing thermal stress generated due to a temperature change.

Further, according to the semiconductor package of the present invention, the cover plate has a plurality of slits or holes for absorbing and diffusing thermal stress generated due to a temperature change. Features.

According to the above construction, the thermal stress is absorbed and diffused by the slits or holes formed in the cover plate in addition to the reinforcing plate, so that the semiconductor package is deformed due to the thermal stress, and the solder ball connection portion is formed. Peeling, cracks and the like are more reliably prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a BGA type semiconductor package according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1 and FIG.
The A-type semiconductor package has a rectangular tape carrier 10 made of, for example, polyimide. A conductive pattern 14 having a large number of pads 12 is formed on the lower surface of the tape carrier 10, and forms a mounting surface 10a. A solder ball 16 is soldered to each pad 12 to form an electrode of a semiconductor package.

At the center of the upper surface of the tape carrier 10, a semiconductor chip 18 is mounted while being connected to the conductor pattern 14. The semiconductor chip 18 and the tape carrier 10 are configured as a tape carrier package. In addition, the peripheral portion and the bottom surface of the semiconductor chip 18 are sealed with the sealing resin 21 to protect the connection portion of the semiconductor chip.

On the upper surface of the tape carrier 10, a reinforcing plate for maintaining the flatness of the tape carrier 10, that is, a stiffener 20 is fixed by an adhesive 22.
The stiffener 20 is formed in a flat plate shape from, for example, stainless steel.

The stiffener 20 is formed in a rectangular shape having the same size as the tape carrier 10.
At its center, a rectangular opening 24 having an outer shape larger than the semiconductor chip 18 is formed. The stiffener 20 is bonded and fixed on the tape carrier 10 in a state where the semiconductor chip 18 is housed in the opening 24, that is, so as to surround the semiconductor chip 18. The stiffener 20 is formed to have a thickness such that the upper surface thereof is at the same level as the upper surface of the semiconductor chip 18.

Further, a plurality of bent slits 26 are formed in the stiffener 20. In particular, these slits 26 are formed in the stiffener 20 at the most distant portions from the semiconductor chip 18, that is, at each corner of the stiffener 20. And these slits 26
As described later, it functions to absorb and diffuse thermal stress generated in the semiconductor package.

The top surface of the stiffener 20 and the top surface of the semiconductor chip 18 are covered with an adhesive 28 by a cover plate 3.
0 is fixed. The cover plate 30 is formed, for example, of copper into a rectangular shape having the same dimensions as the tape carrier 10, and is adhered and fixed on the stiffener and the semiconductor chip 18 while being aligned with the stiffener 20.
The cover plate 30 has a function of radiating heat generated from the semiconductor chip 18 to the outside and a function of protecting the entire semiconductor package.

The BGA type semiconductor package configured as described above is mounted on the mounting surface of the printed wiring board 32. The printed wiring board 32 has an insulating substrate 34 formed of, for example, a glass epoxy resin.
A conductive pattern (not shown) having a large number of pads 36 is formed on the surface of No. 4. The BGA type semiconductor package is electrically and mechanically connected to the printed wiring board 32 by soldering the solder balls 16 to the corresponding pads 36.

In the BGA type semiconductor package having the above structure, when the semiconductor chip 18 generates heat during operation, part of the heat is radiated to the outside via the cover plate 30. At the same time, the tape carrier 10, the stiffener 20, and the cover plate 30 are also heated and thermally expanded. At this time, since these members are formed of materials having different thermal expansion coefficients from each other, the amount of thermal expansion also differs, and a thermal stress is generated in the BGA type semiconductor package. In particular, a relatively large thermal stress is generated at the corner of the semiconductor package that is farthest from the semiconductor chip 18.

However, the BGA according to the present embodiment
According to the type semiconductor package, a plurality of slits 26 are formed at each corner of the stiffener 20, and the thermal stress generated in the BGA type semiconductor package is absorbed and diffused by these slits 26. Therefore, BGA due to thermal stress
Deformation and distortion of the mold package are reduced.

Accordingly, the load acting on each solder ball 16 is reduced, and the connection portion of the solder ball 16, that is, the connection portion between the solder ball 16 and the tape carrier 10, and the connection between the solder ball 16 and the printed wiring board 23 are reduced. Of the solder ball and the occurrence of cracks in the solder ball can be prevented.

Thus, the BG for the printed wiring board is
The reliability of the electrical and mechanical connection of the A-type semiconductor package can be maintained for a long time. In addition, by providing a plurality of slits 26 in the stiffener 20,
The weight of the entire GA type semiconductor package can be reduced.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, as shown in FIG. 3, the stiffener 20 may be provided with a plurality of holes 40 instead of the slits, and the shape of the holes can be variously selected as needed.
Also, as shown in FIG.
0 may be formed uniformly over the entire surface, and the stiffener may be formed in a lattice shape.

In these cases, as in the above-described embodiment, the thermal stress generated in the BGA type package can be absorbed and diffused. Further, as shown in FIG.
A plurality of slits 26 or holes may be provided not only in the stiffener 20 but also in the cover plate 30. In this case, absorption and diffusion of thermal stress and reduction in the weight of the BGA type semiconductor package are more reliably performed. Can be.

In addition, the materials of the tape carrier, the stiffener, and the cover plate are not limited to the above-described embodiments, but can be variously selected as needed. In addition,
4 and FIG. 5, the other configuration is the same as the BG shown in FIG.
The configuration is the same as that of the A-type semiconductor package, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

The present invention is not limited to the BGA type semiconductor package. For example, as shown in FIG. 6, a pin grid array type semiconductor package, or as shown in FIG. The present invention can also be applied to other types of semiconductor packages such as a quad flood type semiconductor package.

In the semiconductor package shown in FIG. 6, lead pins 44 are soldered to the respective pads 12 of the tape carrier 10 instead of the solder balls, and project almost vertically from the bottom surface of the tape carrier. FIG.
According to the semiconductor package shown in FIG.
A part of the conductor pattern 10a extends from a side edge of the tape carrier and forms an electrode 46, respectively.

In the semiconductor package shown in FIGS. 6 and 7, the other structure is the same as the structure of the BGA type semiconductor package shown in FIG. 1, and the same portions are denoted by the same reference characters and are described in detail. Detailed description is omitted.

[0032]

As described above in detail, according to the present invention, a slit or a hole is provided in the stiffener to absorb and diffuse thermal stress, so that the reliability of mechanical and electrical connection is improved. It is possible to provide a semiconductor package which has high reliability for long-term use. Further, by providing a slit or a hole in the stiffener, the weight of the entire semiconductor package can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a BGA type semiconductor package according to an embodiment of the present invention.

FIG. 2 is a sectional view of the BGA type semiconductor package.

FIG. 3 is a perspective view showing a stiffener having a plurality of holes.

FIG. 4 is an exploded perspective view of a BGA type semiconductor package according to another embodiment of the present invention.

FIG. 5 is an exploded perspective view of a BGA type semiconductor package according to still another embodiment of the present invention.

FIG. 6 is a sectional view of a semiconductor package according to another embodiment of the present invention.

FIG. 7 is a sectional view of a semiconductor package according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Tape carrier 10a ... Mounting surface 12 ... Pad 12a ... Mounting surface 14 ... Conductor pattern 16 ... Solder ball 18 ... Semiconductor chip 20 ... Stiffener 26 ... Slit 30 ... Cover plate 32 ... Printed wiring board 40 ... Hole

Claims (5)

[Claims] A tape carrier having a conductor pattern; a plurality of electrodes provided on one surface of the tape carrier and electrically connected to the conductor pattern; and a plurality of electrodes mounted on the other surface of the tape carrier. A connected semiconductor chip, a reinforcing plate fixed on the other surface of the tape carrier so as to surround the semiconductor chip, and maintaining a flatness of the tape carrier; and a reinforcing plate in contact with the semiconductor chip. A cover plate fixed thereon, wherein the reinforcing plate is formed with a plurality of slits or holes for absorbing and diffusing thermal stress generated due to a temperature change. . 2. The tape carrier, the reinforcing plate, and the cover plate are formed in a rectangular shape having substantially equal dimensions, and the slit or hole is formed at a corner of the reinforcing plate. The semiconductor package according to claim 1. 3. A tape carrier having a conductor pattern, a plurality of electrodes provided on one surface of the tape carrier and electrically connected to the conductor pattern, and connected to the conductor pattern mounted on the other surface of the tape carrier. A semiconductor chip, a reinforcing plate fixed on the other surface of the tape carrier so as to surround the semiconductor chip, and maintaining the flatness of the tape carrier; and a reinforcing plate in contact with the semiconductor chip. And a cover plate fixed to the semiconductor package, wherein the reinforcing plate is formed in a lattice shape, and absorbs and diffuses thermal stress generated due to a temperature change. 4. The cover plate according to claim 1, wherein said cover plate has a plurality of slits or holes for absorbing and diffusing thermal stress generated due to a temperature change. A semiconductor package according to claim 1. 5. A tape carrier having a mounting surface on which a plurality of electrodes are formed and a wiring pattern; a plurality of solder balls attached to the electrodes; and a wiring pattern mounted on the other surface of the tape carrier. A semiconductor chip connected to the semiconductor chip; a reinforcing plate fixed on the other surface of the tape carrier so as to surround the semiconductor chip; and a reinforcing plate for maintaining the flatness of the tape carrier; and the reinforcing member in contact with the semiconductor chip. And a cover plate fixed on the plate, wherein the reinforcing plate has a plurality of slits or holes formed therein for absorbing and diffusing thermal stress generated due to a temperature change. package.