JPH08139117A - Formation of enclosure for semiconductor device - Google Patents

Abstract

PURPOSE: To obtain a method for forming an enclosure of semiconductor device using a die having simple structure which can easily deal with an enclosure of different shape. CONSTITUTION: The sealed part of a semiconductor chip 27 or the like, mounted on a lead frame 28 is surrounded by upper and lower elastic frames 31, 24. A sealing resin 26 is fed to the inside and fused and then it is pressed and hardened by means of upper and lower dies 34, 23 while deforming the upper and lower elastic frames 31, 24 elastically in the vertical direction. When the supply of sealing resin 26 fluctuates, elastic deformation of the upper and lower elastic frames 31, 24 varies to absorb the fluctuation without requiring a die having intricate structure. Furthermore, an enclosure having different shape can be dealt with easily by replacing the upper and lower elastic frames 31, 24 with corresponding ones.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an envelope of a semiconductor device by resin sealing.

[0002]

2. Description of the Related Art Conventionally, in a resin-sealed semiconductor device, a semiconductor die is mounted on a lead frame, a glass epoxy resin substrate, or a film substrate, and electrical connection is made, and then an envelope uses a molding die. It was formed by transfer molding or compression molding.

That is, in transfer molding, as shown in FIG. 6, for example, the semiconductor chip 1 is mounted on the mount portion 3 of the lead frame 2 and electrically connected to the corresponding lead portion 4. Next, the lead frame 2 on which the semiconductor chip 1 is mounted is set in the molding die 5 in which the envelope shape of the transfer molding machine is cut.

Thereafter, the molten resin 6 is poured into the molding die 5
It is supplied from the injection section 7 of the molding machine and cured. Then, the molding is performed so that the envelope is molded and the resin-sealed semiconductor device is taken out from the molding die 5.

In the compression molding, as shown in FIG. 7, the molding die 8 of the compression molding machine is fixed to the molding machine, and the upper die 9 and the lower die 10 which form the upper and lower surfaces of the envelope and the molding machine. Spring 1
An upper die 12 and a lower die 13 which are attached via 1 and form the side surface of the envelope are formed.

Then, the lead frame 2 on which the semiconductor chip 1 is mounted and electrically connected is set in the lower mold 10 and the lower mold 13 of the molding die 8 filled with the sheet-shaped resin 14. Subsequently, after covering the semiconductor chip 1 or the like with the sheet-shaped resin 14, the lower mold 10 and the lower mold 13 are raised to match the upper mold 9 and the upper mold 12 to form a predetermined envelope shape. Get it.

Next, the sheet-shaped resin 14 is heated and melted, and then pressed and cured. At this time, the variation in the weight of the sheet-shaped resin 14 filled is absorbed by adjusting the interval between the upper mold 9 and the lower mold 10. Then, the molding is performed so that the envelope is molded and the resin-sealed semiconductor device is taken out from the molding die 8.

However, in each of the above-mentioned conventional techniques, a dedicated molding die 5 is required in accordance with the shape of the envelope of the semiconductor device in the transfer molding, and the molding die 5 has a complicated shape and is difficult to manufacture. It took many days and the mold cost was high. Further, since the molding die 5 is used while being constantly heated to a temperature of around 180 degrees, when the type of the semiconductor device to be manufactured has a different envelope shape and is switched to another molding die 5, it is removed from the molding machine. Replacing the mold 5 with the cooling of the mold and the heating after mounting was a difficult task and required a long replacement time.

Also in compression molding, a dedicated molding die 8 is required depending on the shape of the envelope of the semiconductor device. Further, since the molding die 8 has a structure that absorbs the variation in weight of the sheet-shaped resin 14 to be filled by changing the thickness of the envelope, the molding die 8 has a more complicated structure than the molding die 5 for transfer molding. The mold cost was also high.

[0010]

As described above, in the conventional technique, the molding die for forming the envelope of the semiconductor device requires a dedicated molding die corresponding to the shape, and its structure is complicated. It was. The present invention has been made in view of such circumstances, and an object thereof is a semiconductor having a simple mold structure and capable of easily coping with a case where a semiconductor device to be manufactured has a different envelope shape. It is to provide a method of forming an envelope of a device.

[0011]

According to a method of forming an envelope of a semiconductor device of the present invention, a sealing portion including a semiconductor chip is sealed with an envelope having a predetermined shape by molding a sealing resin. At this time, the sealing part is surrounded by a frame made of an elastic material, and the sealing resin is supplied to the inner part surrounded by the frame to be in a molten state, and the mold is provided so as to confine the sealing resin in the frame. It is characterized in that the frame is elastically deformed and the sealing resin is cured under pressure.
The frame is characterized in that it is formed by arranging a plurality of frame bodies made of an elastic material in an annular shape, and a sealing resin is provided inside the lower elastic frame arranged on the upper surface of the lower mold. After filling with, the lead frame on which the semiconductor chip is mounted is placed on the lower elastic frame so that the sealing portion is located inside, and the upper elastic frame is placed so as to surround the upper side of the sealing portion. After filling the sealing resin inside the upper elastic frame and melting the sealing resin, the lower surface of the upper mold is brought into contact with the upper surface of the upper elastic frame, and then the lower elastic frame is formed by the lower mold and the upper mold. The upper elastic frame is compressed and elastically deformed, and the sealing resin is cured under pressure.

[0012]

According to the method of forming the envelope of the semiconductor device having the above structure, the sealing portion including the semiconductor chip is surrounded by the frame made of the elastic material, and the sealing resin is supplied to the inner portion of the frame. Then, it is melted, and the sealing resin in the frame is pressure-cured while the frame is elastically deformed by a mold. If the amount of the sealing resin supplied varies, the elastic deformation of the frame The variation can be absorbed by changing the quantity, and it is not necessary to have a complicated mold structure. Also, when the shape of the envelope changes due to the change of the type of semiconductor device, it corresponds to the envelope. Since it is only necessary to switch to the frame to be used, it is possible to cope with various different envelope shapes by using only the frame that is easy to manufacture. Further, the development period of the envelope can be shortened and the development cost can be reduced, and the type change can be easily performed without requiring a long time.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, a method of forming an envelope by compression molding according to the first embodiment will be described with reference to FIGS. 1 is a side view showing the first step, FIG. 2 is a view showing the second step, FIG. 2 (a) is a top view, and FIG. 2 (b) is a side view of a main part. 3 is a side view showing the third step, and FIG. 4 is a side view showing the fourth step.

The formation of the envelope will be described below in the order of steps.
In the first step shown in FIG. 1, the lower substrate 2 of the compression molding machine
The lower elastic frame 24 formed in a square ring shape is arranged on the lower mold 23 of the molding die 22 fixed to 1. The lower elastic frame 24 is made up of four heat-resistant resins, such as a polyimide resin, having a rectangular vertical cross-section according to the shape of the lower portion of the envelope of the target semiconductor device, that is, the shape of the sealing portion. The elastic frame member 25 is formed by arranging small gaps at four corners and arranging in a square ring shape.

Then, the inner portion surrounded by the lower elastic frame 24 is filled with a predetermined amount of a sheet-shaped sealing resin 26a made of, for example, an epoxy resin or the like in accordance with the volume of the lower portion of the envelope. The lower die 23 forms the lower surface of the envelope of the semiconductor device, and the lower elastic frame 24 on the lower die 23 forms the lower side surface of the envelope.

On the other hand, the semiconductor chip 27 is mounted on the mount portion 29 of the lead frame 28 and electrically connected to the corresponding lead portion 30. After that, the lead frame 28 on which the semiconductor chip 27 is mounted is placed inside the sheet-shaped sealing resin 2
The lead portion 30 is placed on the lower elastic frame 24 filled with 6a.

Next, in the second step shown in FIG. 2, the upper portion of the envelope is made to correspond to the lower elastic frame 24 on the lead portion 30 of the lead frame 28 placed on the upper surface of the lower elastic frame body 24. An upper elastic frame 31 formed in a square ring shape is arranged according to the shape of the portion, that is, the shape of the sealing portion including the semiconductor chip 27. The upper elastic frame 31 forms the upper side surface of the envelope, and like the lower elastic frame 24, four elastic frame members 32 made of heat-resistant resin such as polyimide resin are provided with small gaps at the four corners. It is formed by arranging in a square ring shape. In addition, between the upper surface of the lower elastic frame 24 and the lower surface of the upper elastic frame 31, as shown in FIG.
As shown in (b), a gap corresponding to the thickness of the lead portion 30 is formed in a portion where the lead portion 30 is not sandwiched.

Next, in a third step shown in FIG. 3, a sheet-shaped sealing resin 26b made of, for example, an epoxy resin is formed in the inner portion surrounded by the upper elastic frame 31 in accordance with the volume of the upper portion of the envelope. Is filled with a predetermined amount. Then, the sheet-like sealing resin 26a, 2 filled inside the lower elastic frame 24 and the upper elastic frame 31 by being irradiated with infrared rays or exposed to a high temperature atmosphere.
6b is heated to form the molten sealing resin 26.

Next, in the fourth step shown in FIG. 4, the heating of the sealing resin 26 is stopped, the lower base 21 of the compression molding machine is raised, and the upper die of the molding die 22 fixed to the upper base 33. The lower surface of 34 is brought into contact with the upper surface of the upper elastic frame 31. As a result, the lead frame 28 having the semiconductor chip 27 is held between the lower mold 23 and the upper mold 34 to hold the lower elastic frame 24.
The upper elastic frame 31 is clamped. The upper mold 34 is the lower mold 2
The upper surface of the envelope of the semiconductor device is formed corresponding to 3.

Subsequently, the lower mold 23 is further raised to compress and elastically deform the lower elastic frame 24 and the upper elastic frame 31 until a predetermined envelope shape is obtained. And
The sealing resin 26 in the lower elastic frame 24 and the upper elastic frame 31 is pressed and cured.

After that, the lower base 21 of the compression molding machine is lowered, and the lower elastic frame 24 and the upper elastic frame 31 are moved from the molding die 22.
The molded product with and is attached is taken out, and the lower elastic frame 24 and the upper elastic frame 31 are removed from the molded product. Thus, a semiconductor device in which the envelope is molded and resin-sealed is obtained.

Although the envelope of the semiconductor device is molded through the above-described steps, in the process of elastically deforming the lower elastic frame 24 and the upper elastic frame 31 in the fourth step, the lower elastic frame 24 is formed. The air taken into the upper elastic frame 31 corresponds to the small gaps at the four corners of the lower elastic frame 24 and the upper elastic frame 31 and the thickness of the lead portion 30 between the lower elastic frame 24 and the upper elastic frame 31. It is released to the outside from the gap. In addition, the respective gaps are closed due to the lower elastic frame 24 and the upper elastic frame 31 being elastically deformed and closely contacted with each other, or the gaps become minute gaps and the melted sealing resin 26 flows in and is closed.

When the amount of the sheet-shaped sealing resin 26a, 26b filled inside the lower elastic frame 24 and the upper elastic frame 31 is varied, the variation is caused by the lower elastic frame 24 and the upper elastic frame. The frame 31 is deformed, and the lower elastic frame 24 and the upper elastic frame 31, and the inner volumes of the lower mold 23 and the upper mold 34 are changed to be absorbed.

Further, when the shape of the envelope is different for different types of semiconductor devices, the same lower mold 23 and upper mold 34 that form the upper and lower surfaces of the envelope are used as they are. The lower elastic frame 24 and the upper elastic frame 31 which are made of a heat-resistant resin and which form the side surfaces of the above are formed and used according to the target product type. Then, the distance between the lower mold 23 and the upper mold 34 is adjusted according to the thickness of the envelope, and a predetermined amount of the sheet-shaped sealing resin is filled, and molding is performed by the same process as above.

As a result, the molding die 22 forming the envelope is composed of the lower mold 23 and the upper mold 34 having a simple shape, the lower elastic frame 24 and the upper elastic frame 31 which can be easily processed, and further the sheet-like sealing. Since the variation in the filling amount of the stopping resins 26a and 26b is absorbed by the deformation of the lower elastic frame 24 and the upper elastic frame 31, the structure does not become complicated and the die cost becomes low.

By preparing the lower elastic frame 24 and the upper elastic frame 31 variously according to the shape of the envelope of the semiconductor device to be manufactured, different envelope shapes can be accommodated, and the envelope development This saves time and effort, and shortens the development period and development costs. Further, even when the manufacturing type is changed, it is only necessary to change the lower elastic frame 24 and the upper elastic frame 31 corresponding to the type, the switching can be easily performed without requiring a long time, and the type can be quickly switched during the manufacturing. .

The semiconductor chip 27 is used in the above embodiment.
Although the above is described as being mounted on the lead frame 28, it may be mounted on a glass epoxy substrate or a film substrate. Furthermore, in the above embodiment, the sheet-shaped sealing resins 26a and 26b were filled and then melted to form the envelope, but a powdery or granular sealing resin may be used.

Next, a method of forming an envelope by transfer molding according to the second embodiment will be described with reference to FIG. FIG. 5 is a side view showing the step of injecting the sealing resin.

In FIG. 5, 41 is a lower mold 42 and an upper mold 4.
The lower mold 42 and the upper mold 43 are formed with recesses 44 and 45, respectively.
These recesses 44 and 45 form a cavity 46 for molding the envelope when the lower mold 42 and the upper mold 43 are combined.

In the space 46, a lower elastic frame 47 formed in a square ring shape according to the shape of the envelope of the semiconductor device to be manufactured.
And the upper elastic frame 48 are arranged in the recesses 44 and 45, respectively. The lower elastic frame 47 and the upper elastic frame 48 are made of a heat resistant resin such as a polyimide resin, and the height dimension thereof is the recesses 44, 4
It is larger than the depth dimension of 5.

Therefore, when the lower mold 42 and the upper mold 43 are combined, the lead frame 28 having the semiconductor chip 27 mounted between the upper surface of the lower elastic frame 47 and the lower surface of the upper elastic frame 48.
The lead portion 30 is pressed and held.

Further, an injection part 50 is connected to the space 46 via a gate 49, and the lower elastic frame 4 provided in the space 46 through the gate 49 from the injection part 50 at the time of molding the envelope.
A molten sealing resin 51 made of, for example, an epoxy resin or the like is injected into the inner portion of the upper elastic frame 7 and the upper portion 7.

Then, transfer molding by the molding die 41 having such a mold structure is performed as follows. First, the lower elastic frame 47 and the upper elastic frame 48 according to the target envelope shape are set in the recesses 44 and 45 of the lower mold 42 and the upper mold 43 of the molding die 41.

Next, the lead frame 28 on which the semiconductor chip 27 is mounted is set between the upper surface of the lower elastic frame 47 and the lower surface of the upper elastic frame 48. Subsequently, the lower mold 42 and the upper mold 43 are combined, and the lead portion 30 is sandwiched so as to be pressed and held at a predetermined temperature.

Thereafter, the sealing resin 51 in a molten state is injected from the injection section 50 through the gate 49 into the inner portions of the lower elastic frame 47 and the upper elastic frame 48, and is surrounded by the lower elastic frame 47 and the upper elastic frame 48. The encapsulating resin 51 filled in the filled inner portion is cured. Then, the lower mold 42 and the upper mold 43 are separated, and the lower elastic frame 47
Take out the molded product with the upper elastic frame 48 attached and
Further, the lower elastic frame 47 and the upper elastic frame 48 are removed from the molded product.
Thus, a semiconductor device in which the envelope is molded and resin-sealed is obtained.

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

In the above embodiment, the sealing resin 51 was formed of epoxy resin or the like. However, a thermoplastic resin is used, and the melted resin is injected into the mold to fill it, and then the mold temperature is cooled. The resin may be cured to obtain a resin-sealed semiconductor device.

[0038]

As is apparent from the above description, according to the present invention, the sealing portion including the semiconductor chip is surrounded by a frame made of an elastic material, and the sealing resin is supplied to the inner portion of the frame to be in a molten state. In addition, since the sealing resin in the frame is pressure-cured while the frame is elastically deformed by a mold, the mold structure is simple and easy to mold envelopes of different shapes. There is an effect such as being able to cope.

[Brief description of drawings]

FIG. 1 is a side view showing a first step in the first embodiment of the present invention.

FIG. 2 is a diagram showing a second step in the first embodiment of the present invention, FIG. 2 (a) is a top view and FIG. 2 (b) is a side view of a main part.

FIG. 3 is a side view showing a third step in the first embodiment of the present invention.

FIG. 4 is a side view showing a fourth step in the first embodiment of the present invention.

FIG. 5 is a side view showing a step of injecting a sealing resin in the second embodiment of the present invention.

FIG. 6 is a diagram showing an outline of conventional transfer molding.

FIG. 7 is a diagram showing an outline of conventional compression molding.

[Explanation of symbols]

 22 ... Mold die 23 ... Lower mold 24 ... Lower elastic frame 26 ... Sealing resin 27 ... Semiconductor chip 28 ... Lead frame 31 ... Upper elastic frame 34 ... Upper mold

Claims (3)

[Claims] 1. When a sealing portion including a semiconductor chip is sealed with an envelope having a predetermined shape by molding a sealing resin, the sealing portion is surrounded by a frame made of an elastic material, and The sealing resin is supplied to the inner portion surrounded by the frame to be in a molten state, and the frame is elastically deformed by a mold provided so as to confine the sealing resin in the frame and the sealing resin is pressure-cured. A method of forming an envelope of a semiconductor device, comprising: 2. The method for forming an envelope of a semiconductor device according to claim 1, wherein the frame is formed by arranging a plurality of frame bodies made of an elastic material in an annular shape. 3. A lower elastic frame disposed on the upper surface of the lower mold is filled with a sealing resin, and then a lead frame having a semiconductor chip mounted on the lower elastic frame is sealed inside. And then the upper elastic frame is placed so as to surround the upper side of the sealing portion, the inside of the upper elastic frame is filled with the sealing resin, and the sealing resin is melted. The lower surface of the upper mold is brought into contact with the upper surface, and thereafter, the lower mold and the upper mold are compressed and elastically deformed by the lower mold and the upper mold, and the sealing resin is pressure-cured. A method of forming an envelope of a semiconductor device, comprising: