JPH07290513A - Mold for sealing semiconductor device with resin - Google Patents

Abstract

PURPOSE:To seal a semiconductor device with resin without generating short circuit and disconnection in metal fine lines or inclination and foam in a semiconductor chip. CONSTITUTION:At an opening 6, a movable member 2 slidable up and down and a gate 4b for injecting a melting resin into a space 3 which has a depth made by descent from an open face to be formed by the descent of the movable member 2 are provided. Firstly, the opening 6 of a lower mold 1b and an opening of the gate 4b are closed, a recess for covering a semiconductor chip of an upper mold is filled with a resin, the side of the semiconductor chip of a lead frame is sealed with the resin. After the resin filling the recess is cured, the movable member 2 is made to descend, the opening of the gate 4b is opened, the desired space 3 is formed, the space 3 is filled with the resin, and the resin sealing is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device resin for resin-sealing a semiconductor device composed of a semiconductor chip mounted on the surface of an island portion of a lead frame and a lead portion of the lead frame. The present invention relates to a sealing die.

[0002]

2. Description of the Related Art In recent years, as semiconductor chips of semiconductor devices have become more highly integrated and have a higher density, the number of pins has been increased, and the number of thin metal wires to be connected to the semiconductor chip and the lead portion of the lead frame has become long. Various problems such as disconnection of metal thin wires and short circuit of adjacent metal thin wires due to the flow of resin occurred during resin sealing. As measures against this, various resin sealing methods and resin sealing molds have been proposed. Japanese Unexamined Patent Publication (Kokai) No. 4-58540 discloses a resin-sealing mold that solves this kind of problem.

FIGS. 3A to 3C are partial cross-sectional views showing the operation sequence of a semiconductor device resin-sealed mold in a conventional example. As shown in FIG. 3, this semiconductor device resin-sealed mold has a concave main mold surface 22 that can move vertically from the bottom of the concave of the lower mold 22 that forms a cavity with the recess 23 of the upper mold 21.
a is provided.

When the semiconductor device is resin-sealed with this mold, first, as shown in FIG. 3A, the recess main mold surface 22a is formed.
The lead frame 2 with the lead frame close to the lead frame.
The semiconductor chip is mounted on the island portion 25 of No. 4 and wired with the fine metal wire 27, and the upper die 21 and the lower die 22 are sandwiched and clamped. Next, as shown in FIG.
The molten resin 29a is injected from 8 and the resin 29a is poured toward the recess 23 having no flow resistance, and the resin 29a is filled in the recess 23 of the upper mold 21 without giving an excessive force to the thin metal wire 27. Then, as shown in FIG. 3C, the concave main mold surface 2
2a is lowered to a desired position, and resin 29 is poured under the lead frame 24 to complete the resin sealing.

As described above, the resin flow direction is regulated to prevent the fine metal wire from flowing or breaking due to the flow pressure of the resin.

[0006]

However, in the above-mentioned semiconductor device resin-sealed mold, although the fine metal wire is not flowed or broken, the resin is injected from the gap between the semiconductor chip and the lead frame. Occurs, and the pressure on the semiconductor chip due to the flow of resin at that time is biased, which often causes the semiconductor chip to tilt. This problem causes the thin metal wires to be exposed from the surface of the resin body even if the semiconductor chip is not exposed from the molded resin shell. In particular, in recent years, there has been a demand for thinner packages, and this problem has come to the forefront.

The molten resin injected from the gate is
Flow not only from above the island, but also directly from below the island from the gate. Then, the resin from the gate receives a large resistance, but the flow velocity becomes slower than the flow velocity of the resin from above the island. As a result, there is a problem that bubbles and unfilled portions are generated at the interface where both resins join together due to the difference in the degree of progress of resin curing.

Therefore, it is an object of the present invention to provide a semiconductor device resin-sealing mold capable of resin-sealing a semiconductor device without short-circuiting or breaking of fine metal wires, inclination of a semiconductor chip, or bubbles. .

[0009]

A feature of the present invention is to seal a semiconductor device, which is composed of a lead portion of a lead frame and a semiconductor chip mounted on the surface of an island portion of the lead frame, with a fine metal wire. In the semiconductor device resin sealing mold, the upper mold having a recess for covering the semiconductor chip and having the first gate for injecting the molten resin into the recess is the same as the opening shape of the recess of the upper mold. A lower die having a second gate having a second gate for injecting the molten resin into the opening, the opening having a shape corresponding to the depression is formed, and the island of the island portion is slid in the opening of the lower die. It is a resin device mold for a semiconductor device, which includes a movable member that can be retained at a position in contact with the back surface and at a position that forms a space apart from the back surface by a predetermined distance. Further, it is desirable that the second gate be closed by the side surface of the movable member at a position where the movable member comes into contact with the back surface of the island portion. Furthermore, in order to increase the contact area between the semiconductor chip and the tip of the movable member, if necessary, only the surface of the tip of the movable member that comes into contact with the island portion should be a flat surface. .

Another feature of the present invention is that the semiconductor chip mounted on the lead frame is housed in the recess of the upper mold, and the movable member is positioned substantially flush with the opening surface of the lower mold. The lead frame is placed on the tip surface of the mold, the mold is clamped, the molten resin is filled into the recess from the first gate, and the filled resin is cured, and then the movable member is moved into the opening. Is a resin sealing method for a semiconductor device using a mold in which a desired space portion is formed by sliding the island portion and the movable member away from each other, and a molten resin is injected into the space portion from the second gate. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A to 1D are sectional partial views showing the operation sequence of a semiconductor device resin-sealed mold in one embodiment of the present invention. As shown in FIG. 1, this resin mold for semiconductor device has an upper mold 1a having a recess 8 for covering a semiconductor chip 26 and a gate 4a for injecting a molten resin into the recess 8.
And a lower mold 1b having an opening 6 having the same shape as the opening of the recess 8 of the upper mold 1a and corresponding to the recess 8 and having a gate 4b for injecting a molten resin into the opening 6, and a lower mold 1b. The movable member 2 is provided which slides in the opening 6 of the mold 1b and comes into contact with the back surface of the island portion 25 and which can be retained at a position where the space portion 3 is formed apart from the back surface by a predetermined distance.

Here, there are two paths for supplying the molten resin to the gate 4a and the gate 4b, and a switching valve (not shown) for switching each path is provided. Further, it is desirable that the side surface of the movable member 2 closes the gate 4b at a position where the movable member 2 contacts the back surface of the island portion 25. The reason for this is that the supply of the molten resin is stopped by the switching valve to prevent the molten resin from flowing out of the gate 4b, but the resin discharged from the gate 4a is prevented from blocking the opening of the gate 4b. That is, the movable member 2 covers the opening 6 of the lower mold 1b and the gate 4b. Furthermore, in order to increase the contact area between the semiconductor chip 26 and the tip of the movable member 2, if necessary, only the surface of the tip of the movable member 2 that comes into contact with the island portion 25 may be a flat surface. is there.

Next, the resin sealing operation of the semiconductor device of this semiconductor device resin sealing mold will be described. First, Fig. 1
As shown in (a), the semiconductor chip 26 is mounted and the lead frame 24 after wire bonding is placed on the movable member 2 whose tip portion is substantially flush with the upper surface of the lower mold 1b.
The upper die 1a and the lower die 1b are clamped. In this state, the opening 6 of the lower mold 1b is closed by the movable member 2 that stays at the upper position, and the opening of the gate 4b is also moved.
It is blocked by the side wall.

Next, as shown in FIG. 1B, the gate 4
The resin is injected from a and the resin 7 a is filled in the recess 8. At this time, since the opening of the gate 4b and the opening 6 of the lower mold 1b are closed by the movable member 2, the molten resin does not flow into the lower mold 1b and the opening of the gate 4b is not closed. Therefore, all the pressure due to the resin flow is received by the tip of the movable member 2.

Next, after the resin filled in the depression 8 is cured,
As shown in FIG. 1C, the movable member 2 is housed in the lower mold 1b to a desired position to form the space 3. And FIG.
As shown in (d), the switching valve is switched to switch the gate 4
A resin that has been heated and melted in advance is injected into the space 3 through b to fill the cavity with the resin 7.

It is necessary to delay the hardening of the resin filling the depression 8 so that the resin filling the depression 8 and the resin filling the opening 6 can be easily bonded. For this purpose, it is desirable to change the cross-linking material contained in the resin of the depression 8. For example, at the time of injecting the resin into the opening 6, if the cross-linking rate of the resin in the depression 8 is about 40%, the resin is surely adhered without dropping to the lower mold 1b.

FIG. 2 is a sectional view showing a modification of the movable member shown in FIG. Since the corner portions of the resin-sealed package body in the above-described embodiment are sharp, chipping easily occurs. Therefore, as shown in FIG. 2, only the mounting surface of the island portion 25 of the lead frame 24 has a flat surface, and the distal end portion of the movable member 2a is formed in a round shape along the peripheral edge portion. If this movable member 2a is loaded into the lower mold 1b of FIG. 1 and sealed with resin, the corners of the package body are rounded and no chipping occurs. Further, if the outer shape of the recess 8 of the upper mold 1a is made the same as the shape of the space 3 formed by the movable member 2a and the opening 6 of the lower mold 1b, the outer appearance of the molded package body is the same as the conventional one. It has a well-balanced shape.

[0019]

As described above, according to the present invention, the movable member capable of sliding vertically in the opening of the lower die and the space portion having the depth due to the lowering from the opening surface formed by the lowering of the movable member. A gate for injecting the molten resin is provided, and first, the opening of the lower die and the opening of the gate are closed, and the resin is filled in the recess that covers the semiconductor chip of the upper die, and the semiconductor chip side of the lead frame is sealed with resin. , After the filled resin is cured,
Since the movable member is lowered to open the gate opening, a desired space is formed, the space is filled with resin, and the back side of the lead frame is resin-sealed, the resin sealing is completed. Unlike the mold, there is no resin that escapes from the upper mold to the lower mold, so that there is no bias pressure. Furthermore, since the semiconductor chip is supported by the tip of the movable member, there is an effect that the semiconductor chip does not tilt. Of course, the short circuit and the wire breakage of the thin metal wire caused by the pressure due to the resin passing through can be similarly eliminated.

Further, since the lead frame side on which the semiconductor chip is mounted and the lead frame side without the semiconductor chip are separately filled with resin, there is no flow resistance member for changing the flow rate of the resin, so that the resin is dented. There is also an effect that it is possible to prevent the generation of bubbles and defects due to the difference in flow velocity that has conventionally occurred in the interior.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an operation sequence of a semiconductor device resin-sealed mold according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a modified example of the movable member of FIG.

FIG. 3 is a cross-sectional partial view showing an operation sequence of a semiconductor device resin-sealed mold in a conventional example.

[Explanation of symbols]

 1a, 21 Upper mold 1b, 22 Lower mold 2, 2a Movable member 3 Space part 4a, 4b, 28 Gate 6 Opening part 7, 7a, 29, 29a Resin 8, 23 Dimple 9 Flat surface 24 Lead frame 25 Island part 26 Semiconductor Chip 27 fine metal wire

Claims (4)

[Claims] 1. A semiconductor device resin encapsulation mold for resin encapsulating a semiconductor device comprising a semiconductor chip mounted on a surface of an island portion of a lead frame and a lead portion of a lead frame, the method comprising: An upper mold having a recess for covering the semiconductor chip and having a first gate for injecting a molten resin into the recess, and an opening having the same shape as the opening of the recess of the upper mold correspond to the recess. A lower mold having a second gate for injecting the molten resin into the opening, and a position that slides in the opening of the lower mold and comes into contact with the back surface of the island portion and a predetermined position from the back surface. A semiconductor device resin-sealed mold, comprising: a movable member that can be retained at a position spaced apart by a distance to form a space. 2. The semiconductor device resin encapsulation mold according to claim 1, wherein the second gate is closed by a side surface of the movable member at a position where the movable member comes into contact with the back surface of the island portion. . 3. The semiconductor device resin-sealed mold according to claim 1, wherein only a surface of the tip end portion of the movable member that contacts the island portion is flat. 4. The semiconductor chip mounted on the lead frame is housed in the recess of the upper mold, and the lead is provided on the tip end surface of the movable member positioned substantially flush with the opening surface of the lower mold. After the frame is placed and the mold is clamped, molten resin is filled into the recess from the first gate, and after the filled resin is cured, the movable member is slid in the opening and the island. And a movable member are separated from each other to form a desired space portion, and a molten resin is injected into the space portion from the second gate.