JP2771475B2 - 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 semiconductor device, and more particularly, to a semiconductor element sealed with a resin.

[0002]

2. Description of the Related Art Referring to FIG. 3, which shows a cross section of a conventional resin-encapsulated semiconductor device, a semiconductor element 32 is fixed on the surface of an island 31, and an internal lead 30 and a semiconductor element 32 are formed.
Are electrically connected to pads on the surface of the semiconductor device by thin wires 29 of gold, aluminum, or the like. These islands 31, semiconductor elements 32, thin metal wires 29, and internal leads 30 are sealed with a resin 24, and from the inside of the resin 24 to the outside. An external lead 30 'is led out.

Here, the island 31, and a large number of external leads 30 'are made of a lead frame (not shown), and are integrated with each other during manufacture. The external lead 30 'is completed. The suspension lead supporting the island 31 is also cut, but may be exposed on the surface of the resin 24 (not shown).

FIG. 4 shows a cross section of a semiconductor substrate used in such a resin-sealed semiconductor device.
Various semiconductor regions 22 having desired circuit functions are formed on a semiconductor substrate 21, an insulating film 23 is formed on the surface thereof, and an internal semiconductor region 22 is formed on the insulating film 23.
Is formed.

The metal wiring 25 is covered with a passivation film 26 except for the bonding pad 27. Such a semiconductor substrate 21 has a scribe region 28.
Are cut and separated from each other by 10.0mm in height and 0.6mm in thickness.
mm, and a semiconductor chip 32 of FIG.
Used as

[0006] In recent years, the surface mounting of this type of resin-sealed semiconductor device has progressed, and a smaller and thinner resin package has been demanded. When a semiconductor element having the above-mentioned predetermined size is incorporated in such a small and thin package, a new problem has occurred, which has not occurred in the related art.

That is, when this type of semiconductor device is surface-mounted on a wiring board of various devices, soldering is performed. At this time, it has been found that peeling occurs along the interface between the resin of the package and the semiconductor element. did. This peeling phenomenon occurs when a stress is generated in a direction along an interface between the resin and the semiconductor element due to a difference in thermal expansion caused by an applied heat in a rapid transition period of 200 ° C. to 350 ° C. at the time of soldering. 200 ° C
It has been found that the more the residual components such as water and cleaning liquid, which are already in a vaporized state, are contained in the resin, the more easily they are generated. It has also been found that the higher the applied heat during soldering, the more easily the heat is generated.

When peeling of the interface occurs, the function of the semiconductor device is hardly affected immediately, but the characteristics gradually deteriorate with the passage of time and reach a level where normal function cannot be achieved. is there.

When such interface peeling occurs, the peeling phenomenon is not limited to the interface but extends to the fragile portion when the resin is thin, reaches the surface of the resin, and communicates with the external atmosphere and the interface. It is considered to be. This is troublesome because it is not immediately visible from the surface of the resin. Therefore, without such an accident being recognized, moisture in the air and the like gradually enters through the peeled portion, causing an electrochemical reaction on the bond pad, the metal wiring, and the like, thereby causing corrosion.

In order to prevent the above-described peeling phenomenon, there is a method of soldering at a relatively low temperature using low-melting solder. However, this method not only reduces the fixing force of the solder but also quickly solders the solder. There is a disadvantage that you can not do the attaching work,
There is also a problem that the amount of water in the resin after resin sealing must be strictly controlled.

Japanese Patent Application Laid-Open No. 3-224 aims to reduce the number of occurrences of resin cracks in a semiconductor device sealed with resin.
With reference to Japanese Patent Application Publication No. 65-65, there is described a technique for preventing concentration of stress by forming a polyimide resin film on the front surface of a semiconductor element and the back surface of an island.

However, such a technique not only adds a step of coating the polyimide resin, but also
There is a problem in that the heat radiation effect is reduced, and there is no effect unless the back surface of the island is coated.

Japanese Patent Application Laid-Open No. 3-233945 discloses a technique for forming an insulating film on the edge of the substrate so that the semiconductor element does not come into contact with the bonding wire.
It has been found that this has only the effect of preventing the electrical contact accident of the wire, and that such an insulating film does not have the effect of preventing the interface peeling reduction.

[0014]

In view of the above problems, the present invention has the following problems. (1) To prevent separation at the interface between the resin of the package and the semiconductor element. (2) There is no need to strictly control the temperature during soldering, and the temperature may be rapidly increased. (3) To withstand stress particularly in the direction along the interface between the resin and the semiconductor element. (4) Avoid being affected by moisture contained in the atmosphere. (5) To prevent the characteristics of the semiconductor device from deteriorating. (7) Soldering work of external leads can be performed quickly. (8) It is not necessary to add a resin coating step.

[0015]

Configuration of the present invention According to an aspect of the bonding pads and inner leads of the main surface of the semiconductor element is electrically connected by metal wires, the semiconductor device obtained by encapsulating in a resin, the bonding Between the pad and the peripheral end of the main surface of the semiconductor element, a band-shaped convex part having a predetermined thickness and width is formed according to the average thickness of the insulating film on the main surface of the semiconductor element.
It is characterized in that it is formed thicker than 1 μm .

In particular, the projection is characterized by comprising an insulating film and a passivation film formed on the surface thereof.

Further, the semiconductor device is characterized in that the convex portion is formed on a surface having a predetermined size inward from a side surface of the semiconductor element.

[0018]

An example of the embodiment of the present invention FIG. 1, theory with reference to FIG. 2
I will tell . The semiconductor substrate 1 of this embodiment has a second insulating film 4
3 and 4 are common to the prior art shown in FIGS. 3 and 4 except for the convex portion 15 formed near the scribe region 8, and the description of the common configuration will be omitted.

[0019] The convex portion 15 is composed of a passivation film covering the surface with an insulating film, the edge of the region to be the scribe region 8 i.e. later semiconductor element 13 of the semiconductor substrate 1
It is formed on the surface at a predetermined dimension from the part . Although the cross section of the convex portion 15 is rectangular, it has a band shape along the peripheral end portion of each region on the main surface of the semiconductor substrate, which will be the semiconductor element 13 later . That is, when viewed from the main surface of the semiconductor substrate, the semiconductor substrate has a rectangular band shape.

On the surface of the first insulating film 3, a second insulating film 4
And metal wiring 5 are formed. The second insulating film 4 is formed with a thickness and a width of about 1 μm to 10 μm on the first insulating film 3 about 100 μm to 200 μm inside the scribe region 8. Although not shown, the second insulating film 4 is formed over the entire surface of each of the rectangular regions which will be the semiconductor element 13 later . The inner surface of the second insulating film 4 is in contact with the side surface of the metal wiring 5 and the outer surface is the first insulating film 3.
On the surface and reaches the scribe area 8.

The surface of the second insulating film 4 and the surface of the first insulating film 3 between the second insulating film 4 and the scribe region 8;
The surface of the metal wiring 5 excluding the bonding pad 7 is covered with a passivation film 6 for protection. The second insulating film 4 which can be formed by known CVD and photolithography techniques is made of polyimide resin, plasma CVDS
iN film, plasma CVD SiON film, or CVDSi
It is formed of an O ₂ film.

The semiconductor substrate 1 formed as described above
The semiconductor element 13 is cut and separated at the scribe region 8 and fixed to the surface of the island 11 as the semiconductor element 13 shown in FIG.
Next, the bonding pad 7 and the internal lead 10
Gold or aluminum thin metal wire 9 of about 0 to 30 μm
Are bonded by thermocompression bonding or ultrasonic thermocompression bonding.

Thereafter, the thermosetting resin material that has been heated and fluidized in advance is injected into a molding die and molded. When the resin material is injected, the resin material uniformly adheres to the surface of the semiconductor element, and the convex portion 1 formed by the second insulating film 4 is formed.
5, and the projections 15 are in a state of being fitted into the resin 12 in a wedge-like manner. To prevent.

That is, the lateral direction 14 of the interface between the sealing resin 12 and the semiconductor element 1 caused by the rapid heat of about 200 ° C. to 350 ° C. applied when the external lead is connected to the wiring board.
Slip can be suppressed. Therefore, the sealing resin 1
No peeling or cracking occurs up to the surface of No. 2; therefore, there is no fear that moisture or the like in the atmosphere may enter and cause a corrosion accident or the like.

Here, the properties of the sealing resin 12 to be used are not particularly limited. For example, an epoxy resin is used, and in addition, a curing agent, a curing accelerator and the like may be contained.

The thickness (height) of the insulating film 4 in this embodiment is:
It must be at least 1.0 μm or more, preferably 2.0 μm or more thicker than the average thickness of the main surface of the semiconductor substrate 1. Further, the width of the insulating film 4 is preferably substantially equal to the thickness.

According to this embodiment, the internal leads 10
When the distance between the pad and the pad 7 is as long as 3 to 5 mm, even if the thin metal wire 9 bends and comes into contact with the semiconductor element 13, even if the thin metal wire 9 comes into contact with the semiconductor element 13, the thin metal wire 9 contacts the convex portion 15 formed by the second insulating film 4. There is no problem to touch. Island 1
When the semiconductor element 13 is fixed to the semiconductor device 1, there is a concern that the mount solder may go up from the side surface. Further, when the semiconductor element 13 is determined to be defective, the ink is picked up or applied as a mark, and the protrusion 15 also functions to prevent the ink from flowing out of the surface of the semiconductor element 13. .

Further, in this embodiment, since only one material is used for the sealing resin 12, there is an advantage that the injection step and the like can be remarkably simplified as compared with the case where two kinds of sealing resins are used.

In this embodiment, a small, surface-mounted
It is not limited to thin flat packages,
In addition, SOP (Small Out-line Pa)
cage), SOJ (Small Out-line)
J-lead), PLCC (Plastic Le)
Also, the present invention can be applied to an added chip carrier.

[0030]

As described above, according to the present invention, each of the above-mentioned problems (1) to (8) can be solved by forming a convex portion on the surface of the semiconductor element which is inside the scribe region by a predetermined dimension. It is not affected by the soldering temperature when mounting the semiconductor device and the moisture in the resin after resin encapsulation, so the management of the soldering temperature and the amount of moisture in the resin becomes unnecessary, and the reliability is further improved. The effect of obtaining a high semiconductor device can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductor substrate according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a sealed state of a semiconductor element obtained from a semiconductor substrate according to one embodiment.

FIG. 3 is a sectional view showing a conventional resin-sealed semiconductor device.

FIG. 4 is a cross-sectional view showing a conventional semiconductor substrate to be sealed with a resin.

[Explanation of symbols]

 1, 21 semiconductor substrate 2, 22 semiconductor region 3 first insulating film 4 second insulating film 5, 25 metal wiring 6, 26 passivation film 7, 27 bonding pad 8, 28 scribe region 9, 29 thin metal wire 10, 30 Internal lead 10 ', 30' External lead 11, 31 Island 12, 24 Sealing resin 13, 32 Semiconductor element 14 Lateral direction 15 Convex part 23 Insulating film

Claims (1)

(57) [Claims] In a semiconductor device in which a bonding pad on a main surface of a semiconductor element and an internal lead are electrically connected by a thin metal wire and sealed with a resin, the bonding pad and a periphery of the main surface of the semiconductor element are provided. Between end portions, a band-shaped convex portion having a predetermined thickness and width is formed to be 1 μm or more thicker than the average thickness of the insulating film on the main surface of the semiconductor device ,
The protruding part is the insulating film and the passive base formed on this surface.
A semiconductor device, comprising a semiconductor film .