JPH0969535A - Sealing die for resin sealed semiconductor device and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the production process while enhancing the reliability and lowering the cost by inserting a movable rod into an upper die to press the surface of a mounting piece against a lower die with a specified pressure and securing the the mounting piece thereby preventing the rear surface thereof from burring. SOLUTION: A semiconductor chip 6 is die bonded to each mounting piece 2 and a lead frame 1, where the semiconductor chip 6 is wire bonded to lead terminals 3, 5, is set in a sealing die. A movable rod 17 is then lowered to press the mounting piece 2 against a lower die 12 and a sealing resin is introduced from a resin injection gate 14 through a gate 15 to fill the cavity 13. In this regard, the mounting piece 2 is secured while being pressed by the movable rod 17 with such pressure as correcting the warp, bend, waving. etc., of the mounting piece 2 itself and eliminating the subtle clearance between the rear surface of mounting piece 2 and the surface of lower die 12. Consequently, the sealing resin does not intrude between the mounting piece 2 and the lower die 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing metal for a resin-sealed semiconductor device having a heat dissipation structure in which the back surface of a mounting piece having a semiconductor chip mounted on the front surface is exposed from the sealing resin surface. The present invention relates to a mold and a manufacturing method using the mold.

[0002]

2. Description of the Related Art A conventional mold for sealing a resin-sealed semiconductor device and a manufacturing method using the same will be described below with reference to FIGS.

7A and 7B are views for explaining a die bonding and wire bonding process of a semiconductor chip to a lead frame, FIG. 7A is a plan view, and FIG. 7B is an enlarged view of a broken line portion. 8A and 8B are views for explaining a conventional resin sealing step and a sealing mold, FIG. 8A is a side sectional view, and FIG. 8B is a perspective view from the upper surface side. FIG. 9 is a diagram showing a conventional lead frame after resin encapsulation.
Is a plan view and (b) is a side view. 10A and 10B are diagrams showing a conventional resin-encapsulated semiconductor device which is a finished product, in which FIG. 10A is a plan view and FIG. 10B is a side view.

First, the structure of the sealing die of the resin-sealed semiconductor device will be described below.

As shown in FIG. 8, a conventional sealing die is
An upper surface molding die 11 and a lower surface molding die 12 are provided, and recesses are formed at predetermined positions of both the molding dies 11 and 12, and the recesses are opposed to each other.
Are stacked, the cavity (sealing space) 13, the resin injection gate 14, and the gate port 15 are formed.

Next, a method of manufacturing the resin-sealed semiconductor device will be described below.

In the lead frame 1 shown in FIG. 7, a plurality of mounting pieces 2 and a plurality of lead terminals 3, 4, and 5 are integrally formed in a unidirectional manner in a multi-striped manner. The lead terminal 4 and the lead terminal 4 are directly connected to each other, and a bending process (not shown) is performed in the vicinity of the connecting portion of the lead terminal 4. Such a lead frame 1
First, the semiconductor chip 6 is die-bonded to each mounting piece 2 with solder, silver paste or the like, and the semiconductor chip 6 and the lead terminals 3 and 5 are internally connected by the bonding wires 7 to form a circuit. In the figure, 8 is a first support tie bar, 9 is a lead tie bar, and 10 is a second support tie bar.

Next, the lead frame 1 on which the semiconductor chip 6 is mounted is placed in a sealing mold as shown in FIG. That is, the lead terminals 3, 4, 5 of the lead frame 1
And each of the tie bars 8, 9 and 10 except the portion corresponding to the resin injection gate 14 of the first support tie bar 8 is sandwiched between the upper surface mold die 11 and the lower surface mold die 12, and the mounting piece 2 is placed on both sides. The molds 11 and 12 are placed in the cavity 13 formed by superimposing them.
Here, the mounting piece 2 is arranged with its back surface in contact with the front surface of the lower surface molding die 12.

After this, a sealing resin (not shown) made of epoxy resin, polyimide resin, or the like is applied from the resin injection gate 14
Is introduced into the cavity 13 through the gate port 15 and is filled.

After the sealing resin is hardened, the resin-sealed lead frame 1 is taken out from the sealing mold. FIG. 9 shows the lead frame 1 after the resin sealing. In the figure, 16 is a sealing resin body.

Finally, the tie bar 8 of the lead frame 1,
By cutting predetermined portions of 9 and 10 and performing lead forming, a resin-sealed semiconductor device as shown in FIG. 10 is completed.

[0012]

However, in the conventional manufacturing method and the molding die, when the mounting piece 2 of the lead frame 1 has a large amount of warp, bending, waviness or surface roughness, the lower surface molding die 12 is used. When foreign matter adheres to the surface or when the mounting piece 2 moves up and down in the sealing space 13 due to the resin injection pressure of the sealing resin, as shown in FIG. A thin resin burr 16a is generated on the back surface.

In this resin-encapsulated semiconductor device, the back surface of the mounting piece 2 is directly soldered to the printed circuit board by a surface mounting device. Therefore, if there is a thin resin burr 16a in this portion, soldering failure with the printed circuit board occurs. Therefore, heat radiation failure from the back surface of the mounting piece 2 will occur.

Therefore, conventionally, in order to remove the thin burr 16a, a thin burr removing step such as a physical removing method or a chemical removing step is added after the resin sealing step. The thin burr removal process causes an increase in cost and a decrease in reliability of the resin-sealed semiconductor device.

In view of the above problems, the present invention prevents the occurrence of thin burrs on the back surface of the mounting piece in the resin sealing step,
An object of the present invention is to provide a mold for encapsulating a resin-encapsulated semiconductor device that can simplify the manufacturing process, improve reliability, and reduce cost, and a manufacturing method using the same.

[0016]

According to a first aspect of the present invention, there is provided a mold for sealing a resin-sealed semiconductor device, wherein a lead is provided with a mounting piece having a semiconductor chip mounted on its surface and a lead terminal. The above-mentioned mounting piece of a frame and a semiconductor chip are sealed with a sealing resin and the back surface of the mounting piece is sealed so as to be exposed from the surface of the sealing resin. A sealing space is formed between the upper and lower molds by overlapping the upper mold and the lower mold, and the placing piece is arranged in the sealing space and the lead terminal is provided. A mold for sealing a resin-sealed semiconductor device, in which the upper mold and the lower mold are sandwiched, and the space for sealing is filled with a sealing resin to seal the mounting piece and the semiconductor chip. In the above, the upper surface mold is inserted, and the surface of the placing piece is pressed against the lower surface mold with a predetermined pressure to perform the mounting. And it is characterized in that formed by providing a moveable plate that presses and fixes the strip.

Further, a sealing die of a resin-sealed semiconductor device according to a second aspect of the present invention is characterized in that the tip of the movable rod has a conical shape.

Further, a method of manufacturing a resin-encapsulated semiconductor device according to a third aspect of the present invention is a method of manufacturing a resin-encapsulated semiconductor device using the encapsulating mold, in which a semiconductor chip is mounted. Placing the placed mounting piece in a sealing space formed between the upper surface mold and the lower surface mold, and sandwiching the lead terminal between the upper surface mold and the lower surface mold; A step of pressing the piece against the lower surface mold with a movable rod to press and fix it; a step of filling the sealing space with a sealing resin in the pressed and fixed state; And a step of separating it from the surface of the mounting piece.

According to the above structure, the resin-molded semiconductor device according to claim 1 of the present invention has a mold for encapsulation, in which the upper mold is inserted, and the surface of the mounting piece is under-molded at a predetermined pressure. Since the movable rod for pressing the mounting piece against the mounting piece is fixed to the mounting piece, the mounting piece is pressed by the movable rod to correct warpage, bending, undulation, etc. of the mounting piece itself and to mount the mounting piece. A mold for encapsulating a resin-encapsulated semiconductor device capable of eliminating a gap generated between a back surface and a surface of a lower surface mold, thereby suppressing a thin burr generated in a resin encapsulation process. can do. Further, in the sealing die of the resin-encapsulated semiconductor device according to claim 2 of the present invention, since the tip of the movable rod is formed into a pyramid shape, the surface of the mounting piece is exposed from the trace of the movable rod of the sealing resin. It is possible to reduce the area to be used.

Further, in the method of manufacturing a resin-encapsulated semiconductor device according to claim 3 of the present invention, a step of pressing the mounting piece against the lower surface mold with a movable rod and pressing and fixing the mounting piece, Since the structure includes a step of filling the sealing space with the sealing resin and a step of separating the movable rod from the surface of the mounting piece after the sealing resin is cured, before the resin is injected into the movable rod. By pressing and fixing the mounting piece to
It is possible to correct warping, bending, waviness, etc. of the mounting piece and to eliminate a gap generated between the back surface of the mounting piece and the front surface of the lower surface mold, and resin filling and resin curing are performed in this state, so that the resin It is possible to suppress the formation of thin burrs on the back surface of the mounting piece that occurs in the sealing step. As a result, it is possible to reduce the physical or chemical thin burr removal process that was conventionally required in the subsequent process of the resin sealing process, simplifying the manufacturing process,
It is possible to improve reliability and reduce cost.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A mold for encapsulating a resin-encapsulated semiconductor device according to an embodiment of the present invention and a manufacturing method using the same will be described below with reference to FIGS. Only the points of this embodiment different from the conventional example will be described.

FIG. 1 is a view for explaining the resin sealing process and the structure of a sealing die of the embodiment, and FIG. 1A is a sectional view showing a state before the mounting piece is pressed and fixed. And (b) is a cross-sectional view showing a state in which the mounting piece is pressed and fixed, and (c).
[Fig. 4] is a perspective view from the upper surface side showing a state where the placing piece is pressed and fixed. 2A and 2B are views showing the lead frame after resin sealing of the embodiment, where FIG. 2A is a plan view and FIG. 2B is a side view. 3A and 3B are diagrams showing a finished product of the resin-encapsulated semiconductor device manufactured in the same example, FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. It is a figure. 4A and 4B are comparison diagrams of manufacturing process flowcharts of the same embodiment and the conventional example. FIG. 4A shows the same embodiment and FIG. 4B shows the conventional example.

First, the structure of the sealing die of the resin-sealed semiconductor device will be described below.

As shown in FIG. 1, the sealing die of the present embodiment is configured such that the upper surface molding die 11 is further inserted into the conventional sealing die so that the inside of the sealing space 13 is closed. It has a structure in which a movable rod 17 that moves up and down is provided.

The movable rod 17 is for forcibly pressing the mounting piece 2 described later from the surface thereof to the surface of the lower mold 12 and is driven and controlled by hydraulic pressure, spring pressure or motor control.

The operation of the movable rod 17 will be described in the manufacturing process described later.

Next, a method of manufacturing the resin-sealed semiconductor device will be described below.

In the manufacturing method of this embodiment, the resin sealing method using the above-mentioned sealing mold is different from the resin sealing method in the conventional manufacturing method.

The resin sealing method will be described below with reference to FIG. 1. As shown in FIG. 7, the semiconductor chips 6 are die-bonded to the mounting pieces 2, respectively, and the semiconductor chips 6 are connected to the lead terminals 3 and 5 by wires. First, the bonded lead frame 1 is placed in a sealing mold as shown in FIG. That is, the tie bars 8, 9, 10 except for the lead terminals 3, 4, 5 of the lead frame 1 and the portion of the first support tie bar 8 corresponding to the resin injection gate 14 are connected to the upper mold die 11 and the lower mold die 12, respectively. And placing the mounting piece 2 in a state in which the back surface of the mounting piece 2 is in contact with the surface of the lower surface molding die 12 in a cavity 13 formed by overlapping the molding dies 11 and 12 with each other. To do. At this time, the movable rod 17 is placed at a position where it does not protrude from the surface of the upper surface molding die 11 in consideration of work efficiency.

Next, as shown in FIGS. 1 (b) and 1 (c),
The movable rod 17 is lowered, and the mounting piece 2 is pressed against the lower surface molding die 12 by the movable rod 17, and the mounting piece 2 is moved.
7 and the lower surface mold 12 are pressed and fixed. Here, as the pressure applied to the mounting piece 2 by the movable rod 17,
A pressure capable of correcting warping, bending, undulation, etc. of the mounting piece 2 itself and pressure capable of eliminating a delicate clearance between the back surface of the mounting piece 2 and the surface of the lower surface molding die 12 are required.

Next, while the mounting piece 2 is being pressed and fixed, a sealing resin (not shown) made of epoxy resin, polyimide resin or the like is guided from the resin injection gate 14 into the cavity 13 through the gate port 15. To fill.

Here, the mounting piece 2 has a pressure capable of correcting warping, bending, undulation, etc. of the mounting piece 2 itself by the movable rod 17, and a slight difference between the back surface of the mounting piece 2 and the surface of the lower surface molding die 12. Since it is pressed and fixed with a pressure that can eliminate such a clearance, there is no gap between the back surface of the mounting piece 2 and the surface of the lower surface mold 12 and there is a seal between the mounting piece 2 and the lower surface mold 12. Stop resin does not enter.

After the sealing resin is hardened, the movable rod 17 is raised to a position where it does not project from the surface of the upper surface molding die 11, and subsequently both molding dies 11 and 12 are opened for resin sealing. The lead frame 1 is taken out.
The lead frame 1 after resin sealing is shown in FIG. In the figure, 1
Reference numeral 6 is a sealing resin body, and 17a is a movable rod mark which is a trace of the movable rod 17.

The resin-sealed lead frame 1 is completed as a resin-sealed semiconductor device as shown in FIG. 3 through tie bar cutting and forming steps. As described above, according to the sealing mold, the mounting piece 2
Can be pressed to correct warpage, bending, undulation, etc. of the mounting piece 2 itself, and to eliminate a gap generated between the back surface of the mounting piece 2 and the surface of the lower surface molding die 12, thereby making it possible to seal the resin. It is possible to suppress thin burrs generated in the stopping process.

Further, according to the above resin sealing step, the thin burr on the back surface of the mounting piece 2 which has been generated in the conventional resin sealing step is not generated, and thus, after the conventional resin sealing step. The thin burr removal step, which was necessary as a processing step, becomes unnecessary.

Therefore, the manufacturing method of the resin-encapsulated semiconductor device according to this embodiment is as shown in FIG. 4 (a), which is different from the conventional manufacturing process shown in FIG. 4 (b). It is possible to simplify the manufacturing process.

Further, since the physical or chemical conventional thin burr removing step is eliminated, the reliability and cost of the resin-sealed semiconductor device can be improved.

The sealing die according to the present invention is not limited to the above embodiment, but may have the following structure. FIG. 5 and FIG. 6 are views showing a finished product of a resin-encapsulated semiconductor device formed by a sealing die according to another embodiment, respectively. In FIG. 5, (a) is a plan view, (b) is a side view, and (c) is a back view. Further, in FIG. 6, (a)
Is a plan view and (b) is a side view. In the figure, 17
b and 17c are movable rod marks.

That is, the movable die of the sealing die may be four (see the movable rod mark 17b in FIG. 5), or the tip of each movable rod may be in the shape of a cone (the movable rod in FIG. 6). Trace 17c).

Here, by making the tip of the movable rod into a cone shape, the exposure of the surface of the mounting piece becomes point exposure, and it is possible to reduce the exposed area of the surface of the mounting piece as compared with the case where the tip is flat. Therefore, it is possible to prevent moisture from entering the resin-encapsulated semiconductor device and prevent the moisture resistance from being lowered.

Besides, the movable rod may be a polygonal column instead of the column.

[0042]

As described above, according to the first aspect of the present invention.
According to the molding die for the resin-encapsulated semiconductor device described above, the mounting piece is pressed by the movable rod to correct warpage, bending, undulation, etc. of the mounting piece itself, and the back and bottom surfaces of the mounting piece. It is possible to eliminate a gap generated between the mold surface and the mold surface, thereby providing a mold for sealing a resin-sealed semiconductor device capable of suppressing thin burrs generated in a resin sealing process. Further, according to the sealing die of the resin-encapsulated semiconductor device according to claim 2 of the present invention, since the tip of the movable rod is formed in a pyramid shape, the surface of the mounting piece is separated from the trace of the movable rod of the sealing resin. It is possible to reduce the exposed area, and it is also possible to prevent deterioration of the moisture resistance of the resin-sealed semiconductor device.

Further, according to the method of manufacturing a resin-sealed semiconductor device according to claim 3 of the present invention, the movable rod corrects warp, bending, undulation, etc. of the mounting piece, and the back and bottom surfaces of the mounting piece. It is possible to eliminate the gap generated between the mold surface and the resin injection and resin curing in this state, so it is possible to suppress the formation of thin burrs on the back surface of the mounting piece that occurs in the resin sealing process. it can. As a result, it is possible to reduce the physical or chemical thin burr removal step that was conventionally required in the subsequent step of the resin sealing step, and to simplify the manufacturing step, improve the reliability, and reduce the cost. .

[Brief description of drawings]

FIG. 1 is a diagram for explaining a sealing die and a sealing method for a resin-sealed semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a lead frame after resin sealing of the embodiment.

FIG. 3 is a diagram showing a finished product of a resin-encapsulated semiconductor device manufactured in the same example.

FIG. 4 is a comparison diagram of the manufacturing process of the resin-encapsulated semiconductor device of the same example and the conventional example, FIG. 4A is the same example;
(B) is a conventional example.

FIG. 5 is a view showing a resin-sealed semiconductor device manufactured by another sealing die.

FIG. 6 is a view showing a resin-sealed semiconductor device manufactured by still another sealing die.

FIG. 7 is a diagram for explaining a die bonding process and a wire bonding process of a semiconductor chip on a lead frame.

FIG. 8 is a diagram for explaining a conventional mold and method for sealing a resin-sealed semiconductor device.

FIG. 9 is a view showing a conventional lead frame after resin sealing.

FIG. 10 is a diagram showing a completed product of a conventional resin-encapsulated semiconductor device.

FIG. 11 is a diagram for explaining a conventional problem.

[Explanation of symbols]

 1 Lead Frame 2 Mounting Piece 3, 4, 5 Lead Terminal 6 Semiconductor Chip 7 Bonding Wire 8 First Support Tie Bar 9 Lead Tie Bar 10 Second Support Tie Bar 11 Top Mold Die 12 Bottom Mold Die 13 Cavity (Sealing Space) Part) 14 resin injection gate 15 gate opening 16 sealing resin body 17 movable rod

Claims (3)

[Claims] 1. A lead frame comprising a mounting piece having a semiconductor chip mounted on the front surface and a lead terminal, wherein the mounting piece and the semiconductor chip are sealed with a sealing resin and the back surface of the mounting piece is Sealing is to be exposed from the surface of the sealing resin, and has an upper surface mold and a lower surface mold, and by sealing the upper surface mold and the lower surface mold, a seal is provided between both molds. A space portion is formed, the placing piece is arranged in the sealing space portion, and the lead terminal is sandwiched between an upper surface mold and a lower surface mold, and the sealing space portion is filled with a sealing resin. In a mold for sealing a resin-sealed semiconductor device that seals the mounting piece and the semiconductor chip, the upper surface mold is inserted, and the surface of the mounting piece is pressed against the lower surface mold with a predetermined pressure. A resin-encapsulated semiconductor device comprising a movable rod for pressing and fixing the mounting piece. Sealing mold. 2. The mold for encapsulating a resin-encapsulated semiconductor device according to claim 1, wherein the tip of the movable rod has a conical shape. 3. A method of manufacturing a resin-encapsulated semiconductor device using the encapsulating mold, wherein a mounting piece on which a semiconductor chip is mounted is formed between an upper mold and a lower mold. It is placed in the sealed space and
The step of sandwiching the lead terminal between the upper surface mold and the lower surface mold, the step of pressing the placing piece against the lower surface mold with the movable rod, and pressing and fixing the above-mentioned mounting piece in the sealing space portion in the pressed and fixed state. A method of manufacturing a resin-encapsulated semiconductor device, comprising: a step of filling an encapsulating resin; and a step of separating the movable rod from the surface of the mounting piece after the encapsulating resin is cured.