JP2715965B2 - Resin-sealed semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device, and more particularly to a resin-sealed semiconductor device suitable for preventing resin cracks.

[0002]

2. Description of the Related Art Conventionally, in a resin-encapsulated semiconductor device, a semiconductor element is fixed on a tab (element mounting portion), and a plurality of leads are arranged around the tab. Are electrically connected by a thin metal wire,
A structure in which the periphery is sealed with a resin is employed.

In recent years, however, there has been a tendency for the dimensions of the semiconductor device to be increased due to the high integration of the semiconductor device. Tend. However, in the conventional structure where the semiconductor element is mounted on the tab, if the dimensions of the semiconductor element are increased while keeping the external dimensions constant,
The length of the portion where the lead is fixed to the resin (the distance between the resin embedded portion of the inner lead portion) is insufficient, and there has been a problem that the lead cannot be provided with sufficient fixing strength.

Therefore, in order to avoid such a problem,
A method of bonding a plurality of inner leads to a circuit forming surface of a semiconductor element with an insulating member interposed therebetween, electrically connecting the inner leads and the semiconductor element with a thin metal wire, and sealing the periphery thereof with a resin. And Japanese Patent Application Laid-Open No. 61-241959. This structure is sometimes called a lead-on-chip. A structure that does not use a tab for the same purpose is a reverse structure of a lead-on-chip, that is, a chip-on-lead. Examples of the chip-on-lead include techniques described in JP-A-1-154545 and JP-A-1-143344.

[0005]

The lead-on-chip is more suitable for high density than the chip-on-lead, but the device for insulating the circuit forming surface of the semiconductor element from each lead. Is required, and Japanese Unexamined Patent Publication No. 61-241959
In the technique typified by Japanese Patent Application Laid-Open No. H11-163, an insulating film is interposed between an inner lead and a circuit formation surface as an electrical insulator.

A polyimide or the like is used as a substrate for this insulating film, but the insulating film substrate generally lacks adhesiveness with a sealing resin.

On the other hand, since it is necessary to electrically connect the circuit formation surface of the semiconductor element and each lead with a wire or the like, the insulating film is usually provided at a necessary portion, that is, in a region where the inner lead is mounted on the upper surface of the semiconductor element. Only used.

In a resin-encapsulated semiconductor device, since the semiconductor elements, inner leads, insulating film, and encapsulating resin which constitute the semiconductor device usually have different coefficients of linear expansion, the process of manufacturing the device and the process of using the device are different. In this case, thermal stress is generated inside the device due to the temperature change of the device. In particular, there is a large difference in the coefficient of linear expansion between the inner lead and the sealing resin. Since the inner lead material and the sealing resin also lack adhesion (adhesion), interface delamination easily occurs for some reason in a situation where thermal stress is applied.

[0009] If the inner lead is tightly adhered and fixed to the circuit forming surface via an insulating film, interfacial peeling should not occur or should be minimized. However, since the adhesive strength between the end surface of the insulating film serving as the adhesive base and the sealing resin also lacks as described above, the end face of the insulating film and the sealing resin are separated by the force separating the inner lead and the sealing resin. Interfacial delamination also occurs during
More and more interfacial delamination will grow.

[0010] Such interfacial peeling causes a resin crack at the upper end of the inner lead, which impairs the appearance of the semiconductor device and causes disconnection of fine metal wires. Particularly, the inner lead in which this danger is large is an inner lead for electrical connection, also called a common (bus) bar.

According to the present invention, a resin-encapsulated semiconductor device capable of preventing the occurrence of a resin crack from the upper end of an inner lead for electrical connection and mounting a semiconductor element as large as possible under a limited external dimension. The purpose is to provide.

[0012]

The object of the present invention is to remove the peeling generated at the interface between the electrical connection (common) lead and the sealing resin.
This is achieved by providing a means for preventing peeling growth so as not to grow to the interface between the end portion of the insulating film and the sealing resin.

The present inventor proposes the following means as a means for preventing peeling growth. Wherein the interface between the first lead and the resin to an extent not cracks occur in the resin first lead
The insulating film interposed under the width of the first lead
Projecting from the end in the
To extend. The insulating film interposed under the first lead is extended on one main surface of the semiconductor element on both sides in the width direction of the first lead, and the insulating film interposed under the second lead is connected to the end of the semiconductor element. Terminate on the inner main surface. Two of the plurality of leads are disposed so as to face each other along the longitudinal direction of one main surface of the semiconductor element, and an insulating film interposed under the two leads is provided with one insulating film between the two opposing leads. To extend on the main surface respectively.

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

By devising as described above, the separation starting from the separation at the interface between the inner lead (shared inner lead for electrical connection) and the sealing resin reaches the interface between the insulating film and the sealing resin. Has a curved point, the straight line cannot travel straight, and at least there is an effect that growth is prevented so that the two are separated from each other. Also under the second lead
Insert the intervening insulating film inside the edge of the semiconductor device.
By terminating on the main surface, the sealing resin
Effect of preventing resin cracks caused by differences in expansion coefficients
There is. That is, the expansion coefficient of the sealing resin and the semiconductor element is
Due to the difference, thermal stress is generated at the end of the semiconductor element.
There is an insulating film at the place where this thermal stress is generated
Because the insulating film does not bear much stress,
Thermal stress concentrates on the resin in contact with the edge, causing resin cracks
Live. Therefore, insulate the insulating film from the end of the semiconductor element.
Termination on the inner main surface, and from the point where thermal stress occurs
Prevent resin cracks by keeping film away
be able to.

The separation of the resin interface generated around the common inner lead and the side surface of the insulating member is separated by the above-described device, so that the amount of deformation of the resin at the upper portion of the common inner lead does not increase. Since no large stress is generated at the upper end of the common inner lead, it is possible to prevent the occurrence of resin cracks from this portion,
Even if a large semiconductor element is mounted, a highly reliable resin-encapsulated semiconductor device can be obtained.

[0021]

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a partial cross-sectional perspective view of a resin-sealed semiconductor device according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along a first line II.

In the drawing, the common inner lead 3 and the signal inner lead 4 have one ends thereof connected to outer leads 5.
The outer leads 5 are disposed in two directions (longitudinal surfaces) of the resin-encapsulated semiconductor device.

The common inner lead 3 has a central portion of the semiconductor element 1 extended in parallel with its long side, and is electrically connected to the semiconductor element 1 on the circuit forming surface 1 a of the semiconductor element 1 by a thin metal wire (wire) 7. Has been done. Although the circuit forming surface 1a is mostly covered with a passivation film such as polyimide, the circuit forming surface is exposed without the passivation film in the area of the electric connection portion.

The signal inner lead 4 extends across each of the long sides of the elongated semiconductor element 1.
The semiconductor element 1 and its tip are electrically connected by a thin metal wire 7 on the circuit forming surface 1 a of the semiconductor element 1. Thus, the main portions of the two common inner leads 3 face each other substantially parallel to each other as opposing surfaces.

The lower surface of the common inner lead 3, the lower surface of the signal inner lead 4, and the circuit forming surface 1 of the semiconductor element 1
A sheet-like insulating member (insulating film) 2 for electrically insulating the common inner lead 3 and the signal inner lead 4 from the semiconductor element 1 is provided between the insulating members 2a. The semiconductor element 1 and the adhesive 9 are bonded together. In the present embodiment, two insulating members 2 are used, and the longitudinal portions of the two shared inner leads 3 are positioned substantially parallel to each other along the opposing side surfaces of the insulating members 2. As shown in FIG. 2, the side surfaces of the member 2 are formed such that the insulating member 2 protrudes from the side surface of the longitudinal portion of the common inner lead 3. In this embodiment, the semiconductor device is formed by sealing the semiconductor element 1, the insulating member 2, the common inner lead 3, the signal inner lead 4, and the thin metal wire 7 with the resin 8.

Bonding between the circuit forming surface 1a of the semiconductor element 1 and the insulating member 2, bonding between the insulating member 2 and the common inner lead 3, bonding between the insulating member 2 and the signal inner lead 4, and bonding between the insulating member 2 and the supporting inner lead 6. Are bonded by an adhesive 9 as shown in FIG. The bonding of the common inner lead 3 and the insulating member 2 may be performed on the entire surface thereof,
It may be a part.

Next, the common inner lead 3, the signal inner lead 4, and the supporting inner lead 6 are
A method of bonding the semiconductor element 1 to the circuit forming surface 1a using the adhesive 9 will be described. Semiconductor element 1
The sheet-shaped insulating member 2 is divided and bonded with an adhesive 9 on positions of the circuit forming surface 1a facing the common inner lead 3, the signal inner lead 4, and the supporting inner lead 6, respectively. Next, the common inner lead 3,
The signal inner lead 4 and the supporting inner lead 6 are bonded and fixed to the circuit forming surface 1a of the semiconductor element 1 via the insulating member 2 with an adhesive 9.

The insulating member 2 is made of a material mainly composed of an epoxy resin, a bismaleimide triazine resin, a phenol resin, a polyimide resin, and the like, to which an inorganic filler, various additives and the like are added. Further, as the adhesive 9, for example, a material such as epoxy, polyetheramide, polyimide precursor, or epoxy-modified polyimide is used.

The common inner lead 3, the signal inner lead 4 and the supporting inner lead 6 are connected to each other until sealed by the resin 8, and form a series of lead frames. It is later cut, separated and molded. The lead frame is made of, for example, Fe-N
It is formed of an i-alloy (such as Fe-42Ni), Cu, or the like.

As the thin metal wire 7, a thin wire such as aluminum (Al), gold (Au) or copper (Cu) is used. ◆
As the sealing resin 8, an epoxy resin to which a phenolic curing agent, silicone rubber and a filler are added is used.

The directions in which the outer leads 5 are drawn out of the resin 8 are not limited to the two directions shown in FIG. 1, that is, the long side of the resin-encapsulated semiconductor device, but may be one direction or The directions may be three or more. Further, the outer leads 5 may be drawn not only from the side surfaces of the resin 8 but also from the upper surface or the lower surface of the resin 8. Further, in the drawing, a J-bend type in which the outer lead 5 is bent downward and its tip is bent to the lower surface of the resin 8 is shown as an example, but the outer lead 5 may be bent in any direction and shape. It is not necessary to bend.

In the above embodiment, the common inner lead 3
And the signal inner lead 4 are distinguished from each other, but a semiconductor device in which the shared inner lead 3 and the signal inner lead 4 are not distinguished, or the shared inner lead 3
However, the present invention can be applied to a semiconductor device having no semiconductor device without departing from the scope of the present invention.

The present embodiment is characterized in that the insulating member 2 protrudes from the side of the main part of the common inner lead 3 to form an extension 2a. By doing so, even if the interface between the resin 8 and the semiconductor element 1 should be separated at the base of the end of the insulating member 2, the interface between the end of the insulating member 2 and the side of the main part of the common inner lead 3 is not flush. However, the peeling action is diffused and attenuated without going straight.

FIG. 3 is a partial cross-sectional perspective view of a conventional tabless resin-sealed semiconductor device to which the present invention is directed, and FIG. 4 is a cross-sectional view taken along a roll line in FIG. A common inner lead (also called a bus bar inner lead) 3 and a signal inner lead 4 are electrically connected to the semiconductor element 1 on the circuit forming surface 1a of the semiconductor element 1 supported (adhered and fixed) by the supporting inner lead 6. The common inner lead 3, the signal inner lead 4, and the semiconductor element are electrically connected to each other by a thin metal wire 7. These are sealed with the resin 8 to form a package.

A noble metal film such as gold (Au) or (Ag) is provided at the joint between the common inner lead 3 and the signal inner lead 4 in order to improve the joint between the inner lead and the thin metal wire. Have been. However, since the adhesion between the noble metal film and the sealing resin is poor, the interface between the inner lead provided with the noble metal film and the sealing resin is easily peeled off. Therefore, the area of the signal inner lead 4 where the noble metal coating 14 is provided is limited to only the thin metal wire joint at the tip of the signal inner lead 4.

However, the common inner lead 3 has a large number of thin metal wires joined and extends over a wider range, so that the noble metal coating 14 is applied to the entire surface of the common inner lead 3 existing above the insulating member 2. FIG.
A hatched portion indicates a region where the noble metal film 14 is provided.

In a resin-encapsulated semiconductor device, the semiconductor elements, inner leads, insulating members, and the encapsulating resin that constitute the semiconductor device usually have different coefficients of linear expansion. Occurs. In particular, when the interface between the common inner lead and the insulating member is separated from the sealing resin, high stress is generated at the upper end of the common inner lead, and a resin crack is generated from this portion.

FIG. 5 is a cross-sectional view schematically showing the mechanism of occurrence of resin cracks. Common inner lead (linear expansion coefficient 5 × 10 ⁶ / ° C) and sealing resin (thermal linear expansion coefficient about 20 × 10
⁶ / ° C.), the interface between the common inner lead 3 and the sealing resin 8 having poor adhesion can be easily formed by cooling after sealing the resin of the semiconductor device or lowering the temperature during the temperature cycle test. Peeling 12 is performed. Incidentally, the thickness of the semiconductor element 1 is, for example, about 0.4 mm, the thickness of the insulating member 2 is about 0.15 to 0.2 mm, and the thickness of each inner lead is about 0.2 mm. When this peeling 12 occurs, the resin contracts in the center direction as shown by the arrow in FIG. For this reason, peeling 12 also occurs at the interface between the insulating member side surface 2d and the resin at the same position as the common inner lead side surface 3d. Since the length of the peeled portion 12 increases the amount of deformation of the resin at the upper portion of the common inner lead, a large stress is generated at the upper end of the common inner lead 3, and a resin crack 13 occurs at this portion.

When the resin crack 13 occurs from the upper end of the common inner lead 3, not only does the appearance of the semiconductor device deteriorate, but also the metal that electrically connects the common inner lead 3 or the signal inner lead 4 and the semiconductor element 1 is formed. Thin line 7
The problem that the wire is broken also occurs. In the above embodiment of the present invention, the occurrence and growth of such interface delamination can be reliably prevented.

[0041]

According to the present invention, since a large stress is not generated due to cooling after resin sealing of a semiconductor device or a decrease in temperature during a temperature cycle test, generation of a resin crack can be prevented. Further, it is possible to obtain a resin-encapsulated semiconductor device capable of mounting as large a semiconductor element as possible under limited external dimensions.

[Brief description of the drawings]

FIG. 1 is a partial sectional perspective view showing one embodiment of a resin-sealed semiconductor device of the present invention.

FIG. 2 is a sectional view taken along the line II in FIG.

FIG. 3 is a partial sectional perspective view showing an example of a conventional tabless semiconductor device.

FIG. 4 is a sectional view taken along the line 2-2 of FIG. 3;

FIG. 5 is a partial cross-sectional view for explaining a mechanism of generation of a resin crack.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor element, 1a ... Circuit formation surface of a semiconductor element, 2 ...
Insulating member, 3 ... common inner lead, 4 ... inner lead for signal, 7 ... thin metal wire, 8 ... resin.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ryuji Kono 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. Inside the laboratory (72) Inventor Ichiro Yasui 5-2-1, Kamimizuhonmachi, Kodaira-shi, Tokyo Inside the Semiconductor Design & Development Center, Hitachi, Ltd. (72) Gen Murakami 5-2-1, Kamimizuhonmachi, Kodaira-shi, Tokyo No. Hitachi Semiconductor Co., Ltd. Semiconductor Design & Development Center (56) References JP-A-61-241959 (JP, A) JP-A-63-208255 (JP, A)

Claims (3)

(57) [Claims] 1. A semiconductor device having one main surface, a first lead having a region along one direction on the one main surface of the semiconductor device, and a direction intersecting the region of the first lead. A plurality of second leads, an insulating film interposed between the two leads and the semiconductor element, and a resin sealing the one main surface of the semiconductor element , the semiconductor device, From the interface between the first lead and the resin so that cracks do not occur in the resin.
The insulating film interposed under the first lead is
The semiconductor which protrudes beyond the widthwise end of the first lead;
A semiconductor device characterized by being extended on one main surface of an element . 2. A semiconductor device having one main surface, a first lead having a region along one direction on the one main surface of the semiconductor device, and a direction intersecting the region of the first lead. A plurality of second leads, an insulating film interposed between the two leads and the semiconductor element, and a resin sealing the one main surface of the semiconductor element , the semiconductor device, The insulating film interposed under the first lead extends on the one main surface of the semiconductor element on both sides in the width direction of the first lead, and the insulating film interposed under the second lead. A semiconductor device, wherein an insulating film is terminated on a main surface inside an end of the semiconductor element. 3. A semiconductor element having one main surface of a rectangle;
A plurality of leads wire-bonded to the semiconductor element; an insulating film interposed between the leads and the one main surface of the semiconductor element ;
And a resin for sealing the main surface , wherein two of the plurality of leads are provided.
The two leads are disposed so as to face each other along the longitudinal direction of the one main surface of the semiconductor element, and an insulating film interposed under the two leads is connected to the main part of the semiconductor element between the two opposing leads. A semiconductor device characterized by being extended on a surface.