JPH1056110A - Plastic package for semiconductor and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic package for a semiconductor which is light and thin and does not warp by a temperature change. SOLUTION: A plastic package 10 for semiconductor comprises a square heat spreader 54 on one surface of which a die attaching part 52 is formed and a circuit substrate 58 of synthetic resin which is adhered to the same surface of the heat spreader 54 and on which a hole 56 for exposing the die attaching part 52 is formed. A reinforcing frame 12 of synthetic resin is adhered to the other surface of the heat spreader 54 for preventing the plastic package 10 for semiconductor from warping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plastic package for a semiconductor and a semiconductor device.

[0002]

2. Description of the Related Art In a plastic package for semiconductors, especially a PGA type or BGA type plastic package, the thermal conductivity of a synthetic resin material itself is low, so that the heat generated from a semiconductor element mounted on the package has conventionally been dissipated. Plastic package for semiconductor 5
0 as shown in FIG. 13, one surface (lower surface in FIG. 13)
And a synthetic resin circuit board 5 having a square heat spreader 54 having a die attach portion 52 formed at the center and a through hole 56 exposing the die attach portion 52 at the center portion.
8, a circuit board 58 is adhered to the heat spreader 54, and the semiconductor element 60 is mounted on the die attach portion 52 to improve the heat dissipation from the semiconductor element 60. . The circuit board 58
In the PGA type plastic package, metal pins are mounted as external terminals 66, and in the BGA type plastic package, solder balls are mounted as external terminals 66. In FIG. 13, it is formed as a BGA type plastic package as an example. Then, using the plastic package for semiconductor 50, the semiconductor element 60 is mounted on the die attach part 52,
After connecting the mounted semiconductor element 60 to the wiring of the circuit board 58 with a wire 62 such as a gold wire, the through hole 56 of the circuit board 58 is formed.
The semiconductor device 68 is manufactured by filling and sealing the inside with a thermosetting sealing resin 64.

[0003]

However, the above-mentioned conventional plastic packages for semiconductors have the following problems. The material of the heat spreader 54 is copper (coefficient of thermal expansion: about 17) having both low material cost and good thermal conductivity.
× 10 ^-6 / ° C) or aluminum (coefficient of thermal expansion: about 24 × 10 ^-6 /
° C) has been used. On the other hand, silicon (thermal expansion coefficient: about 3.5 × 10 ⁻⁶ / ° C.) is used for the semiconductor element 60 bonded to the die attach part 52 of the heat spreader 54, and the heat spreader 5 is surrounded by the semiconductor element 60.
4 is usually made of BT resin or FR.
It is formed of a synthetic resin material reinforced with glass fibers such as 4 (thermal expansion coefficient: about 13 to 15 × 10 ⁻⁶ / ° C.).

As described above, since the coefficient of thermal expansion of the heat spreader 54 is larger than the coefficient of thermal expansion of the semiconductor element 60 and the circuit board 58, when the semiconductor element 60 is mounted on the die attach portion 52 and then sealed with a resin, For example, when the element 60 is energized and generates heat to increase the temperature of the semiconductor device 68, the plastic spread package 50 for the semiconductor tends to warp toward the circuit board 58 as shown in FIG. There was a problem that. Therefore, conventionally, the heat spreader 54 itself is thickened to have rigidity, and even when the temperature increases, the heat spreader 54 is prevented from being warped toward the circuit board 58 by being pulled by the circuit board 58 or the semiconductor element 60 with a small extension. Was.

However, in recent years, electronic devices such as computers in which semiconductor devices are built have become lighter and thinner and smaller.
Accordingly, the weight and thickness of the semiconductor device and the plastic package for the semiconductor itself have been required to be reduced. For this reason, the conventional structure in which the heat spreader 54 is thickened to increase rigidity and prevent warpage is not applicable to the weight reduction and thickness reduction of the semiconductor device and the semiconductor plastic package itself, and thus has a problem that it cannot be adopted.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a plastic package for a semiconductor and a semiconductor device which achieves a reduction in weight and thickness and which is less warped due to a change in temperature while solving the above problems. It is in.

[0007]

According to a first aspect of the present invention, there is provided a plastic package for a semiconductor according to the first aspect of the present invention, comprising: a rectangular heat spreader having a die attach portion on one surface; A plastic package for a semiconductor having a circuit board made of a synthetic resin having a through hole that is bonded to a surface and exposing the die-attached portion, wherein a reinforcing frame made of a synthetic resin is provided on the other surface of the heat spreader. It is characterized by being adhered. Thereby, since the reinforcement frame suppresses the warpage of the heat spreader, the heat spreader can be made thin. In addition, since the reinforcing frame does not have a shape that covers the entire surface of the heat spreader, a decrease in the heat dissipation of the heat spreader due to the attachment of the reinforcing frame can be reduced.

[0008] Specifically, it is preferable that the reinforcing frame has a shape which connects four corners or four sides of the heat spreader and is point-symmetrical. Thereby, it is possible to effectively prevent the warp over the entire area of the heat spreader. The same effect can be obtained even if the reinforcing frame is formed in a cross shape in which at least a part thereof intersects and communicates with the other four corners or four sides facing the four corners or four sides of the heat spreader.

Further, a part of the reinforcing frame may be formed in a square or a circle surrounding the back surface of the die attach portion. According to this, when the semiconductor element mounted on the die attach portion is sealed with a resin, the warp force generated in the heat spreader due to shrinkage due to the hardening of the sealing resin can be locally suppressed, and the warp force It is possible to effectively prevent the entire heat spreader from warping. In addition, since the reinforcing frame is not located on the back surface side of the die attach portion area of the heat spreader, it is possible to attach a radiation fin to this portion.

The reinforcing frame may be formed in a rectangular shape along an edge of the other surface of the heat spreader.

According to a sixth aspect of the present invention, there is provided a plastic package for a semiconductor, wherein a square heat spreader having a die attach portion formed at the center of one surface is bonded to the one surface, and the die attach portion is attached to the central portion. In a plastic package for a semiconductor having a circuit board made of a synthetic resin having a through hole to be exposed, the other surface of the heat spreader is centered on the die attach portion,
A circular concave portion that gradually becomes shallower toward the peripheral edge is formed. When a concave portion is formed in the heat spreader by pressing, cutting, or the like, the heat spreader warps on the concave side when the concave portion is processed. The present invention makes use of this warpage and forms a heat spreader that is flat due to the rigidity of the circuit board when the circuit board is bonded, so that the circuit board always receives a force that tends to warp toward the concave side of the heat spreader. Therefore, the warping force generated by the difference in the coefficient of thermal expansion is canceled, and the warpage of the semiconductor device can be prevented.

A semiconductor device according to a seventh aspect of the present invention is mounted on the plastic package for a semiconductor according to the first, second, third, fourth, fifth or sixth aspect and the die attach portion of the plastic package for a semiconductor. And a plurality of external terminals attached to the circuit board of the plastic package for semiconductor. Since this semiconductor device uses a plastic package for a semiconductor that does not warp even when it is thinned as described above, the warping force acting on the heat spreader due to shrinkage during curing of the resin material that seals the semiconductor element is locally generated. This makes it possible to reduce the thickness of the entire apparatus, and to make it lightweight, without warpage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. (First Embodiment) First, the basic structure of a plastic package for semiconductor 10 and its effects will be described with reference to FIGS. The same components as those of the conventional example are denoted by the same reference numerals. Plastic package for semiconductor 1
As shown in FIG. 2, the characteristic portion 0 is a configuration of a conventional plastic package for semiconductor 50 (see FIG. 13), that is, a square (a die attach portion 52 is formed in the center of one surface (the lower surface in FIG. 2)). In the present embodiment, a heat spreader 54 having a substantially square planar shape and a circuit board 58 made of a synthetic resin having a through-hole 56 formed in the center thereof and exposing the die attach portion 52 are adhered to one surface of the heat spreader 54. In addition to the above configuration, the other surface of the heat spreader 54 (the back surface of the surface on which the die attach portion 52 is formed, the upper surface in FIG. 2) is bonded with a rigid synthetic resin reinforcing frame 12. . As an example of this synthetic resin material, BT resin or F
A synthetic resin material reinforced with glass fiber such as R4 may be used.

With this structure, the heat spreader 54
When the semiconductor element 60 is mounted on the plastic package for semiconductor 10 and sealed with a resin as shown in FIG. Body 12 suppresses,
A planar shape can be maintained. Further, even after the semiconductor device 18 is formed as shown in FIG. 11, the warp force acting on the heat spreader 54 due to the difference in the thermal expansion coefficient between the heat spreader 54 and the circuit board 58 and the heat spreader 54 and the semiconductor element 60 due to the temperature change is suppressed. it can. Also, the reinforcing frame 1
Reference numeral 2 is a so-called frame, so that its shape is not a plane shape that covers the entire area of the other surface of the heat spreader 54. Therefore, a decrease in the heat dissipation of the heat spreader 54 due to the attachment of the reinforcing frame 12 can be minimized.

Next, the specific shape of the reinforcing frame 12 will be described. The warpage generated in the plastic package for semiconductor 10 extends over the entire area of the heat spreader 54. For this reason, the reinforcing frame 12 in the present embodiment has a shape that connects the four corners or four sides of the other surface of the heat spreader 54 and is point-symmetric with respect to the center of the surface.
More specifically, the center of the reinforcing frame 12 is located at the center of the other surface of the heat spreader 54, and the tip extending from the center is located at the periphery (four sides) of the heat spreader 54,
It is formed in a shape that comes into contact with the peripheral edge at right angles, that is, in a cross shape. As shown in FIG. 3, even in the same cross shape, as shown in FIG. 3, a shape extending from the center of the other surface of the heat spreader 54 to reach the four corners of the other surface, that is, the other four corners or four sides facing the four corners or four sides. It may be in a cross shape to cross and contact.
By forming the reinforcing frame 12 in the above shape and bonding the reinforcing frame 12 to the other surface of the heat spreader 54, it is possible to effectively prevent the warp occurring along the vertical and horizontal directions of the heat spreader 54 and the warpage occurring along the diagonal line. Becomes possible. In addition, by combining FIGS. 1 and 3, the tip may extend radially from the center of the other surface of the heat spreader 54 to four sides and four corners of the heat spreader 54.

(Second Embodiment) The basic structure and effect of the plastic package for semiconductor 10 are the same as those of the first embodiment, and the specific shape of the reinforcing frame 12 is different. ing. The shape of the reinforcing frame 12 is the cross-shaped portion 1 described in the first embodiment.
2a is further formed by adding a square portion 12b along the edge of the other surface of the heat spreader 54, as shown in FIGS. Thus, the heat spreader 54
A portion 12b along the edge of the other surface of the reinforcing frame 1
By providing it in a part of 2, it is possible to effectively reinforce warpage and distortion along the peripheral edge portion. In the case where the amount of warpage due to a rise in temperature generated in the heat spreader 54 is small, without combining the above-mentioned cross-shaped shapes,
As shown in FIG. 6, the reinforcing frame 12 may be constituted only by the square portion 12b along the edge of the other surface of the heat spreader 54.

(Third Embodiment) The basic configuration of a plastic package for semiconductor 10 and its effects are the same as those of the first embodiment, and the specific shape of the reinforcing frame 12 is different. ing. As shown in FIGS. 7 and 8, the reinforcing frame 12 has a square (or circular) shape that at least partially surrounds the back surface of the die attach portion 52 (the back surface region of the die attach portion 52 region of the heat spreader 54).
It has a portion 12c. In this embodiment, the shape of the reinforcing frame described in the first embodiment and the second embodiment is also provided. That is, the heat spreader 54 has four corners or four sides 12a on the other surface of the heat spreader 54 centered on the square portion 12c surrounding the die attach portion 52, and a square portion 12b along the edge of the surface. The shape is point-symmetric with respect to the center of the surface.

According to this, when the semiconductor element 60 mounted on the die attach portion 52 is sealed with a resin, the stress generated in the heat spreader 54 due to shrinkage due to the hardening of the sealing resin (this stress becomes a warping force). ) Can be locally suppressed, and the warping force can effectively prevent the entire heat spreader 54 from warping. Further, the reinforcing frame 12 is provided on the rear surface side of the die attach portion 52 of the heat spreader 54.
Is not located, it is also possible to attach a radiation fin (not shown) to this portion. In the present embodiment, the reinforcing frame 12 has a rectangular portion 12b along the edge of the heat spreader 54 in a part thereof, but when the amount of warpage of the heat spreader 54 is small, the rectangular 12b is removed and a portion 12a extending from the central portion of the heat spreader 54 toward four sides or four corners is removed.
May be simply extended further so that the tip of each reaches each side or each corner.

(Fourth Embodiment) First, the basic structure of the plastic package for semiconductor 10 and its effects will be described with reference to FIGS. 9 and 10. FIG. As shown in FIG. 10, the characteristic portion of the plastic package for semiconductor 14 is as follows.
The configuration of the conventional plastic package for semiconductor 50 (see FIG. 13), that is, a square (in the present embodiment, the planar shape is substantially square) in which the die attach portion 52 is formed at the center of one surface (the lower surface in FIG. 10). Heat spreader 5
4 and a circuit board 58 made of synthetic resin, which is bonded to one surface of the heat spreader 54 and has a through hole 56 formed in the center to expose the die attach portion 52, and the other side of the heat spreader 54 On the surface (the upper surface in FIG. 10), as shown in FIGS. 9 and 10, the depth gradually becomes shallower toward the peripheral direction of the heat spreader 54 with respect to the back surface of the die attach portion 52, that is, the cross-sectional shape is The point is that a circular concave portion 16 having an arc shape is formed as shown in FIG.

When the recess 16 is formed in the heat spreader 54 by pressing or cutting, the heat spreader 54 is normally warped toward the recess 16 when the recess is formed. Therefore, by forming the heat spreader 54 to be flat by the rigidity of the circuit board 58 when the circuit board 58 is bonded, the heat spreader 5 is always attached to the circuit board 58.
4 is acting on the concave portion 16 side,
When the temperature rises, the heat spreader 54 and the circuit board 5
8, heat spreader 54 and die attach unit 52
To cancel the warping force caused by the difference in the coefficient of thermal expansion of the semiconductor element 60 bonded to the heat spreader 54, and the warping force generated in the heat spreader 54 due to shrinkage due to the hardening of the sealing resin 64 when the semiconductor element 60 is sealed with a resin. Warpage of the entire semiconductor device 20 can be prevented. By changing the size and depth of the recess 16, the amount of warpage generated in the heat spreader 54 can be adjusted, and when the semiconductor element 60 is mounted and sealed with a resin to form a semiconductor device, the heat spreader 5
4. The circuit board 58 and the external connection terminal 66 can be set so as to be flat.

Further, the semiconductor element 60 is bonded and mounted on the die attach part 52 by using the semiconductor plastic package 10 of the first to fourth embodiments described above.
When the semiconductor devices 18 and 20 are configured as shown in FIG.
When the semiconductor element 60 mounted on the die attach portion 52 is sealed with a resin, the warping force generated in the heat spreader 54 due to shrinkage due to the hardening of the sealing resin 64 can be suppressed. In addition, it is also possible to effectively suppress warpage caused by a difference in coefficient of thermal expansion between the heat spreader 54 and the circuit board 58 and between the heat spreader 54 and the semiconductor element 60 due to a rise in the temperature of the semiconductor device. In particular, in a BGA type plastic package in which the external terminals 66 are formed of solder balls, it is possible to eliminate poor connection of the external terminals 66 due to warpage.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the circuit board and the heat spreader are formed in a rectangular shape as in a multichip module. The present invention can be applied to a case where the shape is formed or a case where the shape is formed in a polygon. The shape of the reinforcing frame is not limited to the point-symmetrical shape as described above, but may be a polygonal shape such as a honeycomb shape or a mesh-like shape formed by a circle. Of course, many modifications can be made.

[0023]

The use of the plastic package for semiconductor according to the present invention reduces the warping force generated in the semiconductor device due to shrinkage due to the curing of the sealing resin when the semiconductor element adhered to the die attach portion is sealed with resin. To prevent warpage. Further, in the semiconductor device using the plastic package for a semiconductor, when the temperature rises, the warping force caused by the difference in the coefficient of thermal expansion between the heat spreader and the circuit board and between the heat spreader and the semiconductor element is effectively suppressed by the reinforcing frame. It has the effect that can be done.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of a plastic package for a semiconductor according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a plan view showing another example of the first embodiment.

FIG. 4 is a plan view of a second embodiment of the plastic package for a semiconductor according to the present invention.

FIG. 5 is a plan view showing another example of the second embodiment.

FIG. 6 is a plan view showing another example of the second embodiment.

FIG. 7 is a plan view of a third embodiment of the plastic package for a semiconductor according to the present invention.

FIG. 8 is a plan view showing another example of the third embodiment.

FIG. 9 is a plan view of a fourth embodiment of the plastic package for a semiconductor according to the present invention.

FIG. 10 is a sectional view taken along line BB of FIG. 9;

FIG. 11 is a sectional view showing a configuration of a semiconductor device using the plastic package for semiconductor according to the first to third embodiments.

FIG. 12 is a sectional view showing a configuration of a semiconductor device using a plastic package for semiconductor according to a fourth embodiment;

FIG. 13 is a sectional view showing an example of a conventional plastic package for a semiconductor.

FIG. 14 is a cross-sectional view illustrating a general configuration of a semiconductor device using a plastic package for a semiconductor;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plastic package for semiconductors 12 Reinforcement frame 52 Die attach part 54 Heat spreader 56 Through-hole 58 Circuit board

Claims (7)

[Claims] 1. A square heat spreader having a die attach portion formed on one surface, the heat spreader being bonded to the one surface,
In a plastic package for a semiconductor having a circuit board made of a synthetic resin having a through hole for exposing the die attach portion, a reinforcing frame made of a synthetic resin is adhered to the other surface of the heat spreader. A plastic package for a semiconductor characterized by the above-mentioned. 2. The plastic package for a semiconductor according to claim 1, wherein the reinforcing frame has a point-symmetrical shape connecting four corners or four sides of the heat spreader. 3. The reinforcing frame body is formed in a cross shape in which at least a part thereof intersects and connects from four corners or four sides of the heat spreader to other four corners or four sides opposed thereto. The plastic package for semiconductor according to the above. 4. The plastic package for a semiconductor according to claim 2, wherein a part of the reinforcing frame is formed in a square or a circle surrounding a back surface of the die attach portion. 5. The plastic package for semiconductor according to claim 2, wherein at least a part of the reinforcing frame is formed in a rectangular shape along a peripheral edge of the heat spreader. 6. A rectangular heat spreader having a die attach portion formed on one surface, the heat spreader being bonded to the one surface,
In a plastic package for a semiconductor having a circuit board made of a synthetic resin having a through hole for exposing the die attach portion, a peripheral direction of the heat spreader is provided on the other surface of the heat spreader with the back surface of the die attach portion as a center. A plastic package for semiconductors, wherein a circular concave portion that gradually becomes shallower toward the substrate is formed. 7. The semiconductor plastic package according to claim 1, 2, 3, 4, 5, or 6, a semiconductor element mounted on the die attach portion of the semiconductor plastic package and sealed, and the semiconductor. And a plurality of external terminals attached to the circuit board of the plastic package.