JPH01220464A - Resin-encapsulated semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the yield of resin cracks and to make a device thin, by using a temporary intermediate indirect material on the surface of a lead frame, mounting an element, bonding the element and the frame with a bonding resin, and sealing the device with a sealing resin. CONSTITUTION:A piece of heat resisting adhesive tape 5 is attached to the surface of a lead frame. A bonding resin 3 is applied on an element mounting part 5a. Thereafter, an element 1 is mounted. When vertical external force is applied on the element 1, the resin 3 is pushed to the outer part of te element 1 and attached to the side surface of the frame 2. After the resin 3 is hardened, the tape 5 is removed, and ultrasonic bonding is performed. At this time, since temperature is low, the resin 3 an sufficiently withstand the temperature. Thereafter, the surrounding part of the device is sealed with a sealing resin 4 and molded. Sine there is no place where the stress is concentrated in the sealing resin at high temperature during reflow, cracks are not yielded in the resin. Furthermore, the device can be made thin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure and manufacturing method of a resin-sealed semiconductor device, and particularly to a structure of the device suitable for preventing resin cracks and reducing the thickness of the device. , and a manufacturing method.

[Conventional technology]

In the conventional device, as shown in a cross-sectional view in the width direction in FIG. 17, the cord 1 is mounted and glued onto a tab 2y of a lead frame consisting of an assembly of leads 2z and an element mounting portion 2y called a tab. , a method was used in which the circumference of the circuit was sealed with a sealing resin 4.

In addition, a structure in which the element and leads are embedded in a resin sheet provided separately from the sealing resin was disclosed in Japanese Patent Application Laid-open No. 60-9764.
It is stated in No. 5.

[Problem to be solved by the invention]

In the above conventional technology, in order to solder an IC to a board,
One method is used: irradiating the solder with infrared rays or exposing it to steam to melt the solder.
C will be directly exposed to high temperatures. Therefore, I
Moisture inside C generates vapor pressure, and as a result, stress concentrates at the bottom corner of the tab (where the anti-element mounting surface of the tab intersects with the side surface of the tab), causing cracks in the sealing resin from the turning section. It is a problem to do so.

In addition, in recent years, due to the demand for high-density packaging of semiconductor devices,
There is a trend toward thinner devices, but with conventional technology,
As mentioned above, this was prevented due to the two-layer construction in which the elements were mounted on top of the tab.

For this reason, if the tab can be eliminated from a resin-sealed semiconductor device, the occurrence of resin cracks in the device can be prevented, and at the same time, the device can be made thinner.

By the way, the Tathagata technology involves a method of placing a somewhat soft resin sheet in a mold for embedding elements and leads, and a method of mounting the element ( There was a lack of consideration in the manufacturing process, such as positioning accuracy during embedding. In addition, the resin sheet is basically intended for mounting elements on it, and is merely a dub made of a different material. Therefore, it is difficult to make the entire device thinner than the conventional type.

Furthermore, in the above-mentioned structure, even if the resin sheet and the sealing resin are made of the same material, the process is different and an interface between the two remains, resulting in the use of a dub with a wider area than the conventional type. Eggplant does not take into consideration the concentration of internal moisture at the interface during reflow, and resin cracks are likely to occur.

In addition, by embedding the tip of the internal lead in the resin sheet, the actual length of the internal lead (distance from the outer edge of the resin sheet to the outer edge of the surrounding sealing resin) is shortened, which reduces moisture absorption. , or reliability at high temperatures may decrease.

An object of the present invention is to overcome the drawbacks of the prior art and provide a resin-sealed semiconductor device that is thin, suitable for mass production, and highly reliable when mounted on a substrate.

[Means to solve the problem]

Among the above objectives, in order to improve the reliability of the device, that is, to prevent the occurrence of resin cracks, and to reduce the thickness of the device, tabs or similar cable mounting parts found in conventional lead frames are eliminated, and the elements and leads are This is achieved by joining the side surfaces and arranging both sides in the same plane.

In addition, in order to manufacture and mass-produce the same device, we temporarily applied an intermediary material such as heat-resistant adhesive tape (hereinafter referred to as tape) to the surface of the lead frame in the direction opposite to the element mounting direction.
By using a manufacturing method in which the tape is removed after the elements are mounted and bonded.

achieved.

[Effect]

According to the method for manufacturing a resin-sealed semiconductor device of the present invention, since the tape is removed after the bonding resin has hardened, the sides of the element and the lead can be bonded with their lower portions being formed on the same surface. Can be done.

Furthermore, according to the resin-sealed semiconductor device of the present invention, since the tab is omitted, there is no lower corner of the tab where stress is concentrated during mounting. Also, since the bottom corner part is filled with the resin for bonding with the lead, it has a structure that is integrated with the lead on the same surface, and there is no concentration of stress at the peripheral edge, so no resin cracks occur. The device becomes thinner.

〔Example〕

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

FIG. 1 is a partial cross-sectional perspective view of a resin-sealed semiconductor device of the present invention, and FIG. 2 is a cross-sectional view of the same in the width direction.

Conventionally, the dove (first
7-2y) is removed, and the element 1 is mounted directly on the same part, and its side surface and the side surface of the tip end of the internal lead 2 surrounding the element 1 are joined with the bonding resin 3, and the element 1 The lower surface and the lower surface of the lead 2 are formed on the same surface. After completing other necessary steps, they are sealed and molded with a sealing resin 4.6 As shown in Figure 2 above, by eliminating the tab, the bottom corner of the tab (171st fi. -8) no longer exists, and therefore, the occurrence of resin cracks can be prevented, and at the same time, the device can be made thinner by at least the width of the tab II.

Next, the outline of the manufacturing method of this device will be explained with reference to FIGS. 3 to 7. A tape 5 such as a heat-resistant adhesive tape is attached to the lead frame 2 prepared in advance for temporarily fixing the lead frame 2 and the element (FIG. 3).

Next, apply the bonding resin 3 to the element mounting part 5a of the tape 5 (Fig. 4). Next, mount the element 1 on the same part (Fig. 5).
. At this time, by applying an external force in the mounting direction of the element,
The bonding resin 3 applied directly under the element is pushed out toward the outer periphery of the element by the pressure, so that it is removed from directly below the element and adheres to the side surfaces of the leads around 1 (FIG. 6). At this time, even if a certain amount of bonding resin remains directly under the cord due to manufacturing reasons, the thickness of the resin is overwhelmingly thinner than that of conventional tabs, so it is possible to make the device thinner. There is no problem in this respect, and there is no difference in the fact that the lower surface from the lead to the resin is formed on the same surface, so there is no problem in preventing the occurrence of resin cracks. After the resin 3 is cured, the tape 5 is removed and wire bonding is performed. As for the wire bonding method, if a thermosonic bonding method or an ultrasonic bonding method is used, a temperature of 150° C. or lower may be used, so that a bonding resin of, for example, epoxy resin can be used. Furthermore, at that time, the heating jig comes into direct contact with the back surface of the element, which has good thermal conductivity, so a preheating process leading up to that point is not necessary. Thereafter, the periphery of the device is sealed and molded with a sealing resin 4 (FIG. 7).

Experiments have demonstrated that the tape removal at this time is not a process that requires particular caution, as the bonding strength from the element to the lead is sufficient if the bonding resin is cured. In addition, by applying a release agent such as vaseline to the tape or to the element or lead frame in advance, the tape can be removed more easily, or the tape can be dissolved and removed using chemicals, heat, etc. You may do so. By the way, the tape is not limited to adhesive tape; for example, cellophane may be attached to the lead frame using static electricity or the like.

In addition, regarding the order of the manufacturing process for one piece, for example, after placing the lead frame and element on the tape, the bonding resin is injected between the adjacent parts of the lead frame and element, etc. Even if there are some changes, the final Generally speaking, the same effect can be obtained.

FIG. 8 to FIG. 10 show the resin-sealed semiconductor MIF of the present invention.
? This is an application example mainly for lead frames, and is particularly aimed at increasing the bonding area of the bonding resin and increasing the bonding strength between the lead and the element.

First, FIG. 8 shows an inclined 2a on the tape attachment side of the internal lead.
However, the round part is not necessarily flat. In FIG. 9, the tip of the internal lead is curved in the direction opposite to the tape attachment direction. However, the round part is not necessarily a curved surface. Figure 10 shows the thickness of the tip of the internal lead (
height) is the same as that of the element. However, the two do not necessarily have to be the same.

In FIG. 11, the application range of the bonding resin is limited to only the adjacent portions of the element 1 and the leads 2, and 6 represents the outer shape of the element, and 7 represents the outer shape of the device. By adopting this coating shape, when element 1 is mounted while applying an external force,
This has the effect of limiting the adhesion range of the bonding resin 3a to only the necessary areas, and at the same time, since the element 1 is directly attached to the adhesive part of the tape surface, the positioning accuracy of the element 1 is improved compared to mounting it in soft resin. Moreover, the residual resin directly below the element can be reduced. FIG. 12 shows the state of the bonding resin at that time, and the broken line portion 3a-2 is the residual resin portion, which does not have any particular influence as described above.

FIG. 14 and FIG. 16 show the above manufacturing method.

8 is a cross-sectional view in the width direction of a resin-sealed semiconductor device in which a tape 5 is individually attached to each device and sealed and molded without the removal step shown in FIG. 7. FIG. Figure 13.

FIG. 15 shows the attachment shape of the tape in each case.

Generally, this tape is much thinner than conventional tabs, so like the residual resin mentioned above, there is no particular problem in achieving the purpose.

In addition, in each of the above examples, SOJ (Small
l 0utline J-bend package)
Although only the types are listed, there are other types, such as D.I.P.
(Dual Line Package), or Q F P (Quad Line Package) with external leads in four directions.
Needless to say, the present invention can be easily applied to flat packages, etc.

〔Effect of the invention〕

According to the present invention, there is no part of the sealing resin where stress is concentrated at the peripheral edge even at high temperatures during reflow, so it is possible to prevent the occurrence of resin cracks and to reduce the thickness by 10% or more compared to conventional types. Become.

Further, according to the method of manufacturing the above-mentioned device of the present invention, the above-mentioned device can be easily manufactured in large quantities with high precision.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional perspective view of an embodiment of the resin-sealed semiconductor device of the present invention, FIG. 2 is a cross-sectional view in the same width direction, and FIGS. 3, 4, 5, 6, and 7 are 8, 9 and 10 are cross-sectional views in the width direction of an applied example of the lead-related relationship of the same device, and FIGS. 11 and 12 respectively show an applied example of the same device's bonding resin coating shape. Figures 13 and 15 are plan views of a lead frame showing an example and the shape of the resin after mounting an element, Figures 13 and 15 are plan views of a lead frame showing examples of tape-related applications of the device, and Figures 14 and 16 are in the width direction of the device. Cross-sectional view, No. 17
The figure is a cross-sectional view in the width direction of a conventional resin-sealed semiconductor device. DESCRIPTION OF SYMBOLS 1...Element, 2...Lead or lead frame, 2a...Internal lead inclined part, 2b...Same curved surface part, 2c...Same thickness part, 2y...Tab, 2z. ...Lead, 3゜3a...Joining resin, 3a-1, 3a-2
... Resin shape after mounting the element, 4... Sealing resin, 5
, 5a. 5b...Tape, 6...Element outer shape, 7...Device outer shape. Fig. 13 Member, 4 Fig. 15 Fig. 16m 5 long, b-, -4 stitches 4 pieces (7: Boots゛Fig. 17 3z--One stamp 3--7)゛T code 7 Shu

Claims (1)

[Claims] 1. Equipped with a semiconductor element (hereinafter referred to as an element), an assembly of leads for electrical connection between the element and the outside, and wires for electrical connection between the element and the leads, and sealed with resin. A resin-sealed semiconductor device molded by bonding the sides of an element and a lead frame using a bonding resin, and sealing and molding the semiconductor device with the sealing resin. Semiconductor equipment.