JPH10144853A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device with an increased manufacturing yield by suppressing vertical movement of a bed fixing a semiconductor element in the case of resin molding a package. SOLUTION: A semiconductor element 16 is fixed on the top face of a square bed 13 formed on a lead frame 12 so as to resin mold a package 21 using a molding die to resin seal. Next, the lead frame 12 is continuously recessed in a specific depth so as to encircle the bed 13 to form an angle circular bed support protrusion 23 as well as making the outer bottom face of this protrusion 23 abut against the inner face of the molding die in the case of the resin molding so as to make the outer bottom face expose in the outer face of the package 21 after the molding step. Through these procedures, even if the bed 13 is moving in the vertical direction by the umbalanced state of the resin injected along the surface of the lead frame 12 in the case of molding the package 21, the movement is restricted and suppressed by the bed support protrusion 23 abutting against the inner face of the molding die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art As is well known, a semiconductor device has a semiconductor element fixed to a bed of a lead frame, and a thermosetting resin is injected into a molding die to form a package and perform resin sealing. is there. Hereinafter, a conventional resin-sealed semiconductor device will be described with reference to FIG. FIG. 7 is a sectional view. In FIG. 7, the semiconductor device 1 has a semiconductor element 4 fixed to the upper surface of the bed 3 of the lead frame 2, and a terminal 5 of the semiconductor element 4 and an inner end of the lead 6 of the lead frame 2. Are electrically connected by a bonding wire 7, and a package 8 is formed by resin molding using a thermosetting resin using a molding die (not shown). The outer ends of the extended leads 6 are cut to have a predetermined length, and at the same time, the extended leads 6 are formed into a predetermined shape.

[0003] In a molding step of performing resin molding of the package 8 using a molding die, the bed 3 to which the semiconductor element 4 is fixed is supported so as to be suspended in the molding die, and then the lead frame is placed in the molding die. A thermosetting resin is injected along the surface of No. 2. Then, the inside of the mold is filled with the thermosetting resin, and after a predetermined curing time, the lead frame 2 on which the package 8 is formed is taken out from the mold.

However, in the above prior art,
When the resin of the package 8 is molded, a thermosetting resin is injected into the molding die along the surface of the lead frame 2.
The semiconductor element 4 is provided between the upper and lower sides of the lead frame 2.
The flow resistance on the upper surface side where the resin is fixed is larger than that on the lower surface side, so that the resin does not easily flow, and the amount of the upper and lower thermosetting resin in the molding die divided by the lead frame 2 is reduced. If there is a difference, the semiconductor element 4 and the bed 3 are moved up and down due to the difference in the amount of resin. As a result, the bonding wires 7 are exposed on the outer surface of the package 8, voids are generated on the semiconductor element 4, and the bed 3 designed to be sealed in the package 8 is exposed on the lower surface, which is not preferable in appearance. There was a risk of becoming a state.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation. When a package is molded with a resin using a molding die, a bed of a lead frame and a semiconductor element fixed to the bed are vertically moved. It is an object of the present invention to provide a semiconductor device having an improved manufacturing yield by suppressing movement of the bonding wire in the direction, reducing exposure of a bonding wire to an outer surface of a package, generation of a void on a semiconductor element, and the like.

[0006]

According to the present invention, there is provided a semiconductor device comprising:
In a semiconductor device including a bed formed on a lead frame, a semiconductor element fixed to the bed, and a package in which the semiconductor element is resin-sealed together with the bed by resin molding using a molding die, A bed support projection formed to be exposed on the outer surface of the package,
Furthermore, the bed support projection is formed so as to be continuous with the periphery of the bed, and further, the bed support projection is provided between the suspension pins for suspending and supporting the bed in the lead frame. Wherein the bed support projection is formed so as to project in the direction of the back surface side with respect to the semiconductor element fixing surface of the bed. .

[0007]

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

First, a first embodiment will be described with reference to FIGS. 1 is a sectional view, FIG. 2 is a perspective view of a main part of a lead frame before resin sealing, and FIG. 3 is a rear view of the package. 1 to 3, a semiconductor device 11 has a semiconductor element 16 on an upper surface 15 located below a lead frame surface 14 of a bed 13 formed in a square shape of a lead frame 12 made of a metal material such as a 42 alloy. It is configured to be fixed by solder or silver paste brazing material. And the semiconductor element 16
The plurality of terminals 17 and the inner ends 19 of the plurality of leads 18 formed on the lead frame 12 are electrically connected to each other by bonding wires 20. The package 21 is formed on the lead frame 12 in which the semiconductor element 16 is fixed on the bed 13 by resin molding using a thermosetting resin such as an epoxy resin mixed with a silica filler and set in a molding die (not shown). Resin sealing such as 16 is performed.

On the other hand, around the bed 13, the lead frame 12 is recessed so as to have a predetermined depth so as to surround the bed 13, that is, the lead frame 12 is formed so as to be convex downward, so that the upper side of the bed 13 is formed. A bed support protrusion 23 formed so that the bottom surface 22 is located below the front surface 15 is provided in a rectangular ring shape, and the outer bottom surface 24 of the bed support protrusion 23 similarly forms a rectangular ring-shaped plane. Therefore, when the package 21 is formed by resin molding, the outer bottom surface 24 of the bed support projection 23 is
Exposed on the outer surface of At the upper part of the four corners of the outer wall of the bed support projection 23, suspension pins 25 extending radially outward from the corners are provided, the outer ends of which are connected to the lead frame 12, and The bed 13 surrounded by the bed support projections 23 is suspended and supported by an intermediate portion in the lead frame 12 by these suspension pins 25.

The lead frame 12 on which the package 21 is formed and sealed with resin is connected to the suspension pins 25 extending from the package 21 to the outside and the outer ends 2 of the leads 18.
6 are cut at predetermined positions, and the outer ends 26 of the leads 18 extending at the same time by a predetermined length are formed into, for example, a predetermined gull wing shape, and the semiconductor device 11 is formed.

In the above-described configuration, in the molding step of performing resin molding of the package 21 using a molding die, the outer bottom surface 24 of the bed support projection 23 is formed when the lead frame 12 is set in the molding die. Contact the inner surface of the mold. When the thermosetting resin is injected into the mold along the surface of the lead frame 12 in a state where the outer bottom surface 24 of the bed support projection 23 is in contact with the inner surface of the mold, the resin becomes It flows in a direction along the surface of the lead frame 12 under the influence of the semiconductor element 16 fixed to the bed 13. At this time, a force that pushes down the bed 13 is applied to the lead frame 12 toward the lower surface side where the resin injection is delayed due to the flow resistance by the bed support protrusion 23 and the resin amount is reduced. However, the bed 13 is prevented from moving in the vertical direction because the bed support projection 23 is in contact with the inner surface of the mold, and the semiconductor element 16 fixed to the bed 13 is resin-sealed at a predetermined position in the package 21. .

As described above, according to the present embodiment, since the bed support protrusion 23 is provided so that the outer bottom surface 24 is exposed to the outer surface of the package 21, the cross-sectional area of the flowing portion of the injected resin is small. Although a downward force acts on the lead frame 12, the lead frame 12 is not deformed even if a force such as pushing down the bed 13 does not move up and down, and the bonding wire 20 is exposed on the outer surface of the package 21. And the occurrence of voids on the semiconductor element 16 is reduced, and the outer bottom surface 24 of the bed support protrusion 23 is designed to be exposed on the outer surface of the package 21 so that appearance defects are reduced. Manufacturing yield is improved.

The ratio of the amount of resin on the upper and lower surfaces of the lead frame 12 can be changed by appropriately setting the shape of the bed support projection 23, and the like.
The amount of warpage can be easily adjusted, and the thickness of the package 21 can be reduced. Further, the heat generated by the semiconductor element 16 can be released to the outside from the outer bottom surface 24 of the bed support projection 23 exposed on the outer surface of the package 21. If the outer bottom surface 24 is configured to be in contact with a separately provided radiator, more effective cooling can be performed.

Next, a second embodiment will be described with reference to FIGS. 4 is a cross-sectional view of the suspension pin portion, FIG. 5 is a perspective view of a main part of the lead frame before resin sealing, and FIG. 6 is a rear view of the package. FIG.
In FIG. 6 to FIG. 6, a semiconductor device 31 is formed by soldering or mounting a semiconductor element 16 on an upper surface 15 located below a lead frame surface 33 of a bed 13 formed in a square shape of a lead frame 32 made of a metal material such as a 42 alloy. It is configured to be fixed by a brazing material of silver paste. The plurality of terminals 17 of the semiconductor element 16 and the inner ends 19 of the plurality of leads 18 formed on the lead frame 32
Means that the corresponding one is a bonding wire 20
Are electrically connected by In addition, the semiconductor element 1
6 is fixed on a bed 13, a lead frame 32 is set in a molding die (not shown), and a package 34 is formed by resin molding with a thermosetting resin such as an epoxy resin mixed with a silica filler. Sealing is performed.

On the other hand, the outer ends of the suspension pins 35 extending radially outward from the four corners of the bed 13 are connected to the lead frame 32, and the bed 13 is suspended and supported by an intermediate portion in the lead frame 32. It is in a state. Further, the suspension pin 35 is provided with a bed support convex portion 36 formed in a middle portion by forming a trapezoidal concave or concave process to have a predetermined depth, that is, by processing the convex portion downward. The bed support projection 36 has a bottom 37
When the package 34 is formed by resin molding, the outer bottom surface 38 of the bed support projection 36 is exposed to the outer surface of the package 34.

In the lead frame 32 in which the package 34 is formed and sealed with resin, the suspension pins 35 extending outside from the package 34 and the outer ends (not shown) of the leads 18 are cut at predetermined positions. At the same time, the outer ends of the leads 18 extending by a predetermined length are formed into, for example, a predetermined gull wing shape, and the semiconductor device 31 is formed.

With the above-described structure, in the molding step of performing resin molding of the package 34 using the molding die, the bed support projection 36 formed on the suspension pin 35 when the lead frame 32 is set in the molding die. Outer bottom surface 38
Abuts against the inner surface of the mold. And the bed support protrusion 36
When the thermosetting resin is injected into the molding die along the surface of the lead frame 32 in a state where the outer bottom surface 38 is in contact with the inner surface of the die, the resin becomes the shape of the lead frame 32 and the bed 13.
Flows in the direction along the surface of the lead frame 32 under the influence of the semiconductor element 16 fixed to the lead frame 32. At this time, a force that pushes down the bed 13 is applied to the lead frame 32 toward the lower surface side where the injection of the resin is delayed due to the flow resistance by the bed support protrusion 36 and the resin amount is reduced. But,
The bed 13 is prevented from moving up and down because the bed support projection 36 is in contact with the inner surface of the mold, and the semiconductor element 16 fixed to the bed 13 is sealed with a resin at a predetermined position in the package 34.

As a result, the same operation and effect as in the first embodiment can be obtained in this embodiment.

[0019]

As is apparent from the above description, according to the present invention, by providing the lead frame with the bed support protrusion so that the outer bottom surface is exposed on the outer surface of the package, there is a possibility that the package may be formed when the resin is molded. The vertical movement of a certain bed and a semiconductor element fixed to the bed can be suppressed, the exposure of bonding wires to the outer surface of the package and the occurrence of voids on the semiconductor element can be reduced, and the manufacturing yield can be improved. It works.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the lead frame before resin sealing according to the first embodiment of the present invention.

FIG. 3 is a back view of the package according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a suspension pin according to a second embodiment of the present invention.

FIG. 5 is a perspective view of a main part of a lead frame before resin sealing according to a second embodiment of the present invention.

FIG. 6 is a rear view of the package according to the second embodiment of the present invention.

FIG. 7 is a sectional view of a conventional technique.

[Explanation of symbols]

 12, 32 ... lead frame 13 ... bed 16 ... semiconductor element 21, 34 ... package 23, 36 ... bed support protrusion 24, 38 ... outer bottom surface 35 ... hanging pin

Claims (4)

[Claims] A bed formed on a lead frame;
In a semiconductor device comprising a semiconductor element fixed to the bed and a package obtained by sealing the semiconductor element with a resin by using a molding die together with the bed, the lead frame is exposed on an outer surface of the package. A semiconductor device comprising a bed support projection formed to perform the following. 2. The semiconductor device according to claim 1, wherein the bed support projection is formed so as to be continuous with the periphery of the bed. 3. The semiconductor device according to claim 1, wherein the bed support projection is formed at an intermediate portion of a suspension pin for suspending and supporting the bed in the lead frame. 4. The semiconductor device according to claim 1, wherein the bed supporting projection is formed so as to project toward the back surface side with respect to the semiconductor element fixing surface of the bed.