JPH11284122A - Resin-sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the warpage of a semiconductor element and die pad after die-bonding, avoid poor bond or poor loop due to the warp and defects due to the poor injection of resin to avoid deteriorating the adhesion of the seal resin to the die pad. SOLUTION: A frame-like metal plate 5 bonded through an adhesive layer 4 to the back side of a die pad 3 is made of a metal material having approximately the same metal as the metal of a frame or equal thermal expansion coefficient to thereof and here the frame 11 and metal plate 5 are made of Cu or Cu alloy. For bonding the frame-like metal plate 5 to the die pad 3 there are methods using adhesive materials or welding methods. Adequate no. of metal plates 5 may be bonded or bridge may be provided across the frame-like metal plate 5 according to the warp degree due to the pattern difference of the die pad 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device using a copper frame.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view showing a structure of a conventional resin-encapsulated semiconductor device using a copper-based frame after die bonding. In the figure, reference numeral 1 denotes a semiconductor element, 3 denotes a die pad made of copper or a copper alloy to which the semiconductor element 1 is fixed using a die bonding material 2, 6 a is disposed around the die pad 3, and the electrode of the semiconductor element 1 and a thin metal wire Is a semiconductor frame composed of the die pad 3, the inner lead 6a and the like. In recent years, with an increase in the speed and integration of the semiconductor element 1, the amount of heat generated from the semiconductor element 1 tends to increase, and it is important to increase the heat radiation of a package surrounding the semiconductor element 1. Therefore, recently, as a material for the frame 11, a copper-based frame made of copper and a copper alloy having high thermal conductivity has been increasingly used in place of the conventional iron-based frame.

[0003]

However, since the copper frame has lower strength and a larger thermal expansion coefficient than the conventional iron frame, as shown in FIG. 8, the semiconductor element 1 and the die pad are bonded after die bonding. 3 tends to warp upward. As described above, when the semiconductor element 1 and the die pad 3 are warped upward, there is a gap between the die pad 3 and the heat block 7 at the time of the next wire bonding as shown in FIG. When the semiconductor element 1 and the die pad 3 vibrate up and down when they come into contact with the electrode 9 on the element 1, there is a problem that the bonding of the thin metal wires 10 becomes unstable and a bonding failure such as peeling of the bonding portion occurs.
Further, as shown in FIG. 10, after bonding the electrode 9 on the semiconductor element 1 and the thin metal wire 10 and moving the thin metal wire 10 to the inner lead 6a, the semiconductor element 1 and the die pad Vertical vibration remains, and this vibration is transmitted from the electrode 9 to the thin metal wire 10, causing a problem of a loop defect in which the thin metal wire 10 is broken.

On the other hand, as a method for preventing a package from warping or cracking due to a difference in thermal expansion coefficient between a semiconductor element, a lead frame and a sealing resin, for example, Japanese Patent Application Laid-Open No.
In JP-A-83551, as shown in FIG. 11, a resin sealing type in which a metal plate 13 having a smaller thermal expansion coefficient than that of the lead frame 11 is bonded to the back side of the semiconductor element 1 mounting portion of the lead frame 11 by an adhesive 14. Semiconductor devices have been proposed. According to this method, it is considered that the strength can be improved even in the above-described copper-based frame, and the warpage can be suppressed. However, in the current resin-encapsulated semiconductor device, the thickness of the encapsulation resin 12 tends to be reduced due to the reduction in the thickness of the package. In particular, the thickness of the encapsulation resin 12 below the lead frame 11 is about 0. 2m
m. Joining the metal plate 13 to the back side of the lead frame 11 in such a state of thinning increases the volume of the contents of the package. There is a problem in that the sealing resin 12 cannot be sufficiently wrapped around, and a failure due to the non-injection of the sealing resin 12 occurs. In addition, there are cases where a large number of holes are provided in the semiconductor element mounting portion (the die pad 3 in FIG. 8) of the lead frame 11 mainly for improving the adhesion to the sealing resin 12, and in this case, the metal plate The hole is closed by joining 13
There is also a problem that the adhesion between the lead frame 11 and the sealing resin 12 is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and suppresses warpage of a semiconductor element and a die pad after die bonding, and prevents bonding failure and loop failure due to warpage. It is an object of the present invention to provide a resin-sealed semiconductor device that prevents defects due to non-injection of a sealing resin and does not impair the adhesion between the sealing resin and a die pad.

[0006]

In a resin-sealed semiconductor device according to the present invention, a semiconductor element is fixed using a die bond material on a die pad of a frame in which leads are arranged in a peripheral portion, and the semiconductor element is sealed with a resin. And a frame-shaped metal plate is joined to a peripheral portion of the back surface of the die pad. Further, a bridge for reinforcing the frame is provided in the frame of the metal plate. Further, a resin-sealed semiconductor device in which a semiconductor element is fixed using a die bonding material on a die pad of a frame in which leads are arranged in a peripheral portion, and is resin-sealed. Are bonded together.

The metal plate is made of the same metal material as the frame or a metal material having a coefficient of thermal expansion substantially equal to that of the metal of the frame. Further, the frame and the metal plate are made of copper or a copper alloy. The metal plate is bonded to the die pad using an adhesive. The metal plate is joined to the die pad by welding.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a structure after die bonding of a resin-sealed semiconductor device according to a first embodiment of the present invention, and FIG. 2 is a plan view. In the figure, 1 is a semiconductor element, 3 is a die pad made of copper or a copper alloy to which the semiconductor element 1 is fixed using a die bonding material 2, 5 is bonded to the peripheral portion of the back surface of the die pad 3 via an adhesive layer 4. The frame-shaped metal plate 6a is disposed in the periphery of the die pad 3 and is connected to an electrode (not shown) of the semiconductor element 1 by a thin metal wire (not shown), and 11 is the die pad 3 and the inner lead 6a. It is a frame for a semiconductor configured from the above. In the semiconductor device according to the present embodiment, the semiconductor element is fixed on the die pad 3 of the frame 11 in which the inner leads 6a are arranged in the peripheral portion using the die bonding material 2, and is sealed with a resin in a later sealing step. And a frame-shaped metal plate 5 is bonded to the back surface of the die pad 3 using an adhesive. The metal plate 5 is made of the same metal material as the frame 11 or a metal material having a thermal expansion coefficient substantially equal to that of the metal of the frame 11. In the present embodiment, the frame 11 and the metal plate 5 are made of copper or a copper alloy. is there.

FIG. 3 is a sectional view showing a resin-sealed semiconductor device after resin sealing according to the present embodiment. In the figure, 6b is an outer lead, and 12 is a sealing resin. In recent years, packages are becoming thinner, and their thickness is about 1
mm. Among them, the thickness of the semiconductor element 1 is about 0.3 mm, the thickness of the frame 11 is about 0.125 mm, and the thickness of the sealing resin 12 is smaller at the lower part (L ₂ ) than at the upper part (L ₁ ). ing. In the present embodiment, the thickness of the metal plate 5 is about 0.125 m, which is almost the same as that of the frame 11.
m, and the shape is a frame shape that reinforces only the peripheral portion of the back surface of the die pad 3, so that the sealing resin 12
The space around the lower part is ensured, and the occurrence of a failure due to the non-injection of the sealing resin 12 is prevented. Further, the die pad 3 may be provided with a large number of holes mainly for improving the adhesion to the sealing resin 12, and even in such a case, the frame-shaped metal plate 5 according to the present embodiment may be provided. Then, the die pad 3 can be reinforced without impairing the effect of the hole of the die pad 3.

As described above, according to the present embodiment, by bonding the frame-shaped metal plate 5 to the peripheral portion of the back surface of the die pad 3, the warpage of the semiconductor element 1 and the die pad 3 after die bonding is suppressed. Vibration in the vertical direction of the semiconductor element 1, which has conventionally occurred at the time of wire bonding in the next step, can be eliminated, and bonding failure and loop failure due to this vibration can be prevented. Also, by forming the metal plate 5 in a frame shape,
A space around the sealing resin 12 can be secured, and defects due to the non-injection of the sealing resin 12 can be prevented. Further, even when a large number of holes for improving the adhesion with the sealing resin 12 are provided in the die pad 3, all the holes are not closed, so that the die pad 3 is reinforced without impairing the adhesion. It is possible.

In this embodiment, the frame-shaped metal plate 5
Was bonded to the back surface of the die pad 3, but a frame-shaped metal plate 5 may be bonded to the surface of the die pad 3 as shown in FIGS. Further, the number of metal plates 5 to be joined is not limited to one, and the size of the semiconductor element 1 and
An appropriate number of metal plates 5 may be overlapped and joined depending on the degree of warpage due to the difference in pattern of the die pad 3.
As described above, the frame-shaped metal plate 5 according to the present embodiment has a high versatility because the number of metal plates 5 can be changed according to the amount of warpage. Further, several kinds of frame-shaped metal plates 5 having different thicknesses may be prepared.

Embodiment 2 FIG. FIG. 6 is a sectional view showing a structure after die bonding of the resin-encapsulated semiconductor device according to the second embodiment of the present invention. In the drawings, the same or corresponding parts have the same reference characters allotted, and description thereof will not be repeated. The present embodiment is characterized in that, when joining the frame-shaped metal plate 5 to the back surface of the die pad 3, the joining is performed by welding without using the adhesive layer 4 used in the first embodiment. Also in the present embodiment,
The same effect as in the first embodiment can be obtained, and further, since the thickness of the adhesive layer 4 is eliminated, space can be saved, which is advantageous for the encapsulation resin 12 to go around, and a defect due to the non-injection of the encapsulation resin 12. Can be prevented. In addition, when the frame-shaped metal plate 5 is joined to the surface of the die pad 3, the joining by welding according to the present embodiment can be applied, and the same effect can be obtained.

Embodiment 3 FIG. 7 is a plan view showing a shape example of a metal plate used in the resin-sealed semiconductor device according to the third embodiment of the present invention. In the figure, 5a is a metal plate provided with two parallel bridges on a frame-shaped metal plate, and 5b is a metal plate provided with two bridges crossing diagonally of the frame-shaped metal plate. In the first and second embodiments, instead of the frame-shaped metal plate 5 that reinforces only the peripheral portion of the die pad 3, a metal plate 5 provided with a bridge as shown in the present embodiment is used.
a and 5b may be used, and a stronger effect of suppressing warpage of the semiconductor element 1 and the die pad 3 can be obtained. However, the metal plates 5 a and 5 b provided with the bridge are bonded only to the back surface of the die pad 3. The number and positions of the crosslinks are not limited to the above. Also, a plurality of crosslinked metal plates 5a and 5b may be overlapped and joined according to the amount of warpage of the semiconductor element 1 and the die pad 3.

[0014]

As described above, according to the present invention, a semiconductor element is fixed on a die pad of a frame in which leads are arranged in a peripheral portion by using a die bonding material, and is resin-sealed. In a semiconductor device, by joining a frame-shaped metal plate to the peripheral portion of the rear surface or the front surface of the die pad,
Conventionally, warpage of a semiconductor element and a die pad which has occurred after die bonding can be suppressed, and bonding failure and loop failure due to vibration generated at the time of wire bonding in the next step can be prevented.

Further, by forming the metal plate joined to the back surface of the die pad into a frame shape, a space where the sealing resin goes around the lower portion of the die pad is secured, and a defect due to the non-injection of the sealing resin is prevented.
In addition, a resin-sealed semiconductor device that does not impair the adhesion between the die pad and the sealing resin can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure after die bonding of a resin-sealed semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a structure after die bonding of the resin-encapsulated semiconductor device according to the first embodiment of the present invention;

FIG. 3 is a sectional view showing a resin-sealed semiconductor device according to the first embodiment of the present invention;

FIG. 4 is a sectional view showing a structure after die bonding of another resin-encapsulated semiconductor device according to the first embodiment of the present invention;

FIG. 5 is a plan view showing a structure after die bonding of another resin-encapsulated semiconductor device according to the first embodiment of the present invention;

FIG. 6 is a cross-sectional view showing a structure after die bonding of a resin-encapsulated semiconductor device according to a second embodiment of the present invention;

FIG. 7 is a plan view showing a shape example of a metal plate used in a resin-sealed semiconductor device according to a third embodiment of the present invention;

FIG. 8 is a cross-sectional view showing a structure after die bonding of a conventional resin-encapsulated semiconductor device.

FIG. 9 is a cross-sectional view for explaining a problem of the conventional resin-encapsulated semiconductor device after die bonding.

FIG. 10 is a cross-sectional view for explaining a problem of a conventional resin-encapsulated semiconductor device after die bonding.

FIG. 11 is a cross-sectional view showing a conventional resin-encapsulated semiconductor device in which a metal plate is joined to the back surface of a lead frame.

[Explanation of symbols]

1 semiconductor device, 2 die bonding material, 3 die pad,
4 adhesive layer, 5, 5a, 5b metal plate, 6a inner lead, 6b outer lead, 7 heat block, 8 tool, 9 electrode, 10 metal thin wire, 11 frame, 12 sealing resin, 13 metal plate, 14 adhesive .

Claims (7)

[Claims] 1. A resin-sealed semiconductor device in which a semiconductor element is fixed using a die bonding material on a die pad of a frame in which leads are arranged in a peripheral portion, and is resin-sealed. A resin-encapsulated semiconductor device, wherein a frame-shaped metal plate is joined to the portion. 2. The resin-encapsulated semiconductor device according to claim 1, wherein a bridge for reinforcing the frame is provided in the frame of the metal plate. 3. A resin-sealed semiconductor device in which a semiconductor element is fixed using a die bonding material on a die pad of a frame in which leads are arranged in a peripheral portion, and is resin-sealed. A resin-encapsulated semiconductor device, wherein a frame-shaped metal plate is joined to the portion. 4. The resin according to claim 1, wherein the metal plate is made of the same metal material as the frame or a metal material having a thermal expansion coefficient substantially equal to that of the metal of the frame. Sealed semiconductor device. 5. The resin-sealed semiconductor device according to claim 4, wherein the frame and the metal plate are made of copper or a copper alloy. 6. The resin-encapsulated semiconductor device according to claim 1, wherein the metal plate is bonded to the die pad using an adhesive. 7. The resin-encapsulated semiconductor device according to claim 1, wherein the metal plate is joined to the die pad by welding.