KR200169834Y1 - Semiconductor package - Google Patents

Abstract

This invention relates to a semiconductor package, which improves the bonding force between the conductive wire and the inner lead in the semiconductor package using heat sinks, lead frames, etc., enhances the adhesive force between the heat sink and the encapsulant, and fixes a fixed window size. In order to use an adhesive tape having a lead in various sizes, a semiconductor chip is bonded to an adhesive on a heat sink, and a lead frame having an inner lead is bonded to an adhesive tape on a heat sink of the outer periphery of the semiconductor chip. The semiconductor chip and the inner lead are bonded with conductive wires, and the semiconductor chip, the conductive wire, and the inner lead on the heat sink are encapsulated with an encapsulant. The window size formed by the adhesive tape as a distance is based on the semiconductor chip. A semiconductor package which is formed to be larger than a window size formed by an inner lead as a predetermined distance facing each other.

Description

Semiconductor Package {semiconductor package}

The present invention relates to a semiconductor package, and in more detail, in a semiconductor package using a heat sink, a lead frame, etc., the bonding strength between the conductive wire and the inner lead is improved, and the adhesion between the heat sink and the encapsulant is improved. At the same time, the present invention relates to a semiconductor package capable of using adhesive tapes having fixed window sizes for leadframes of various sizes.

The resin encapsulated semiconductor package, which is generally known in the art, has a structure in which one semiconductor chip is encapsulated with an encapsulant such as an epoxy molding compound, and is used for mounting on a main board. A structure called a lead frame with leads is used to form a delivery system. In addition, in order to efficiently dissipate heat generated from the semiconductor chip, a heat sink is attached to one surface of the semiconductor chip.

A typical example of such a semiconductor package is shown in FIG. 3, which is briefly described as follows.

Figure is a cross-sectional view showing the structure of a resin-encapsulated semiconductor package using a conventional lead frame and heat sink, in the drawing reference numeral 1 is a semiconductor chip, 2 is a semiconductor chip using an adhesive (3, usually epoxy adhesive, after curing Heat sink which is easily hardened by heat dissipation, and is attached to the top surface of the heat sink, which is the outer circumference of the semiconductor chip. And a lead frame that is electrically connected to the outside of the semiconductor chip 1, and 5 is electrically connected and connected to the inner lead 4a of the lead frame 4 and the semiconductor chip 1. The conductive wires shown in Fig. 6 each show a body which seals and seals the semiconductor chip 1 on the heat sink 2, the inner lead 2a of the lead frame 4, the conductive wire 3, and the like with an encapsulant. .

As shown, the semiconductor chip 1 and the lead frame 4 are attached and fixed on the heat sink 2 with the adhesive 3 and the adhesive tape 7 interposed therebetween. The inner lead 4a of the lead frame 4 is electrically connected and connected by the conductive wire 3. The predetermined area including the semiconductor chip 1, the inner lead 4a of the lead frame 4, and the conductive wire 5 is sealed with an encapsulant to form a substantially rectangular body 6. In addition, on both sides of the body 6, the out lead 4b for mounting on the main board is protruded and formed while maintaining a predetermined interval.

Such a conventional semiconductor package has a lead frame attaching process for attaching the lead frame 4 to the heat sink 2 via an adhesive tape 7, and the semiconductor chip 1 on the heat sink 2 with an adhesive 3. A die bonding step of attaching the semiconductor chip, a wire bonding step of electrically connecting the semiconductor chip 1 and the inner lead 4a of the lead frame 4 with the conductive wires 5, and the semiconductor A molding process of encapsulating a predetermined area including the chip 1, the inner lead 2a, and the conductive wire 5 with an encapsulant to form the body 6, and each lead of the lead frame 4; Through a trim / forming process of cutting a dambar (not shown) that supports the bent and bending the out lead 4b protruding to both sides of the body 6 into a predetermined shape. The semiconductor package thus manufactured has its out lead 4b on its main board. Lower ripple by matching the pattern (pattern) that is mounted by soldering (soldering reflower) is a function such that the input and output electrical signals.

However, in such a semiconductor package and its manufacturing process, some problems arise due to the adhesive tape for adhering the lead frame (particularly the inner lead portion) onto the heat sink. That is, since the adhesive tape has some degree of elasticity after curing, the bonding force between the conductive wire and the inner lead is reduced in the process of bonding the inner chip of the semiconductor chip and the lead frame with the conductive wire.

More specifically, the wire bonding process is usually performed by a mechanism called capillary, which first bonds conductive wires to the semiconductor chip, and then continuously ultrasonically vibrates the other end of the conductive wires on the inner lead. Bonding is done using energy. At this time, since the adhesive tape is elastic, the inner lead vibrates finely up, down, left, and right, resulting in a decrease in the bonding force of the bonding portion between the inner lead and the conductive wire.

The problem is that the conductive wire is easily short-circuited in the pull strength test for testing the bonding force of the conductive wire, or the bonding portion of the inner lead and the conductive wire is formed by a high-pressure encapsulant in a molding process. This breaks easily and causes many defects in the semiconductor package manufacturing process.

Therefore, the present invention was devised to solve the conventional problems as described above, and improves the bonding force between the conductive wire and the inner lead in the semiconductor package using the heat sink, lead frame, etc., and the adhesive force between the heat sink and the encapsulant. At the same time to provide a semiconductor package that can be used for the lead frame of various sizes, the adhesive tape having a fixed window size.

Figure 1a is a plan view showing a state in which the adhesive tape is bonded to the lower inner lead of the lead frame according to the present invention, Figure 1b is a cross-sectional view showing a semiconductor package according to a first embodiment of the present invention, Figure 1c is a wire It is a state diagram which shows the bonding state.

2 is a cross-sectional view showing a semiconductor package according to a second embodiment of the present invention.

3 is a cross-sectional view showing a conventional semiconductor package.

-Description of the main symbols in the drawings-

One; Semiconductor chip 2; Heat sink

3; Adhesive 4; Lead frame

4a; Inner lead 4b; Out lead

4c; Bend 5; Conductive wire

6; Body 7; Adhesive tape

8; Insulating material 20; Capillary

30; Clamping w; Window

a, b; Window size

In order to achieve the above object, in the semiconductor package according to the present invention, a lead frame having an inner lead is bonded to the inner circumference of the heat sink top surface with an adhesive tape, and a semiconductor chip is bonded to the center of the heat sink top surface with an adhesive. A semiconductor chip and an inner lead are bonded with a conductive wire, and a semiconductor package in which the semiconductor chip, the conductive wire, and the inner lead on the heat sink are encapsulated with an encapsulant, wherein an upper peripheral surface of the heat sink around the semiconductor chip The adhesive tape positioned at is characterized in that the adhesive is bonded to the outside of the bonding region of the inner lead to which the wire is connected.

Here, the inner lead region in contact with the end portion of the adhesive tape facing the semiconductor chip is bent at an angle so that the remaining inner lead region is in contact with the heat sink.

In addition, the upper portion of the heat sink is preferably coated with an insulating material so that the short between the inner lead does not occur.

As described above, according to the semiconductor package according to the present invention, wire bonding is performed while the inner lead is directly supported on the heat sink to improve the bonding force between the inner lead and the conductive wire. In addition, since the insulating material is coated on the heat sink, the adhesion between the encapsulant and the heat sink may be further increased. In addition, the window size of the adhesive tape is significantly larger than the window size of the lead frame, so that it can be applied to all lead frames within a certain range, thereby lowering the manufacturing cost of the semiconductor package.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

FIG. 1A is a plan view showing a state in which an adhesive tape 7 is adhered to an inner lead 4a of the lead frame 4, and FIG. 1B is a cross-sectional view showing a semiconductor package according to a first embodiment of the present invention. 1C is a state diagram showing a wire bonding state.

First, referring to FIG. 1A, the lead frame 4 has a window w of a predetermined space in a central portion thereof, and a plurality of inner leads 4a are formed to extend radially about the window w. The outlead 4b is formed to extend to the inner lead 4a. A dam bar is formed between the inner lead 4a and the out lead 4b to prevent the encapsulant from flowing out during the molding process.

An adhesive tape 7 having a window size b larger than the window size a of the lead frame 4 is bonded to the bottom of the inner lead 4a of the lead frame 4. That is, the adhesive tape 7 is bonded to the bottom surface of the inner lead 4a near the dam bar, and the width thereof is also significantly smaller than in the prior art, thereby reducing the expensive adhesive tape 7. Therefore, the adhesive tape 7 is not positioned on the bottom surface of the inner lead 4a in the region bonded with the conductive wire.

Subsequently, referring to FIG. 1B, a portion of the inner lead 4a is adhered to the upper surface of the heat sink 2 by the adhesive tape 7, and the remaining inner lead 4a portion. Is spaced apart from the upper surface of the heat sink 2 by a predetermined distance. The adhesive tape 7 temporarily attaches the lead frame 4 to the heat sink 2 until the molding process, and also prevents the inner lead 4a from contacting the heat sink 2 and shorting each other. do.

The semiconductor chip 1 is bonded to the window w formed by the lead frame 4 on the upper surface of the heat sink 2 by the adhesive 3, and the adhesive 3 has a property of hardening after curing. As a result, the bonding force between the conductive wire and the semiconductor chip 1 will not be reduced.

The inner lead 4a of the semiconductor chip 1 and the lead frame 4 is bonded with a conductive wire, and a predetermined region of the semiconductor chip 1, the conductive wire, the lead frame 4 and the heat sink 2 is bonded. Silver is to be protected from the external environment by the body (6) sealed with a sealing material.

The outlead 4b of the lead frame 4 protrudes outside the body 6 to be mounted on the main board, and the bottom surface of the heat sink 2 is exposed to the outside to the outside of the semiconductor chip 1. Easily dissipate heat to the outside.

Referring to the wire bonding state in more detail in the semiconductor package as described above are as follows.

As shown in FIG. 1C, during the wire bonding process, the inner clamp 4a of the lead frame 4 is brought into close contact with the heat sink 2 so that the fixed clamp 30 is lowered so that the inner lead 4a does not move. All are fixed on the heat sink (2). In this state, the capillary 20 ball-bonds one end of the conductive wire to a predetermined portion of the semiconductor chip 1, and then stitches the other end of the conductive wire to a predetermined region of the inner lead 4a. It will be stitch bonding. Of course, the ultrasonic vibration energy is transmitted to the capillary 20 during the ball bonding or the stitch bonding, and bonding is performed by the energy.

Here, the elastic adhesive tape 7 is not positioned below the inner lead 4a and the area where the conductive wires are bonded, and the hard heat sink 2 is directly positioned, so that the wires are bonded to each other. Likewise, the inner lead 4a moves up and down and does not absorb the bonding force, thereby improving the bonding force between the inner lead 4a and the conductive wire.

On the other hand, if the fixing clamp 30 is removed on the inner lead 4a after the wire bonding process is completed, the inner lead 4a is returned to its original position, and the inner lead 4a is as shown in FIG. Is positioned horizontally.

Here, in order to completely block the electrical short between the inner lead 4a and the heat sink 2, it is preferable to coat the insulating material 8 on the upper surface of the heat sink 2, but the present invention is limited to this. no.

2 is a cross-sectional view showing a semiconductor package according to a second embodiment of the present invention.

As shown in the second embodiment of the present invention, the window size b of the adhesive tape 7 is larger than the window size a of the inner lead 4a of the lead frame 4. Therefore, the elastic adhesive tape 7 is not positioned on the bottom of the inner lead 4a bonded to the conductive wire, and the heat sink 2 made of a hard material is directly contacted. In addition, since the bent portion 4c bent downward is formed in the inner lead 4a portion of the lead frame 4, that is, the inner lead 4a portion that is the boundary area with the adhesive tape 7, the semiconductor chip 1 The remaining inner lead portion 4a facing) is completely in contact with the upper surface of the heat sink 2.

Therefore, when the inner lead 4a is more firmly adhered to the heat sink 2 during wire bonding, the bonding force is improved, and as shown in the first embodiment, the inner lead 4a moves upward after completion of the wire bonding. By not returning, there is an advantage that the bonding state of the conductive wire is also maintained well.

Meanwhile, in the first embodiment, the coating of the insulating material 8 on the heat sink 2 was optional. In the second embodiment, the insulating material 8 should be coated. This is because the inner lead 4a is always in contact with the upper surface of the heat sink 2 by the bent portion 4c, so that a short may occur between the inner leads 4a. In addition, when the insulating material 8 is coated as described above, adhesion to the encapsulant is also improved, and thus, an interface peeling phenomenon between the body 6 and the heat sink 2 may be reduced.

In addition, the conventional lead frame 4 has to adjust the window size (b) of the adhesive tape 7 for each window size, in the present invention, the window size (b) of the adhesive tape 7 is By being much larger than the window size (a), the adhesive tape 7 of the same size can be used for the lead frame 4 in a relatively wide range, thereby lowering the manufacturing cost of the semiconductor package.

As described above, although the present invention has been described with reference to the above embodiments, the present invention is not limited thereto, and various modified embodiments may be possible without departing from the scope and spirit of the present invention.

Therefore, according to the semiconductor package according to the present invention, wire bonding is performed while the inner lead is directly supported on the heat sink, thereby improving the bonding force between the inner lead and the conductive wire.

In addition, since the insulating material is coated on the heat sink, the adhesive force between the encapsulant and the heat sink is further increased to reduce the interfacial peeling phenomenon.

In addition, the adhesive tape can be applied to all leadframes regardless of the window size formed by the inner lead of the leadframe, thereby reducing the manufacturing cost of the semiconductor package.

Claims (3)

A lead frame having an inner lead is bonded to the inner circumference of the heat sink top surface with an adhesive tape, and a semiconductor chip is bonded to the center of the heat sink top surface with an adhesive, and the semiconductor chip and the inner lead are bonded with conductive wires. In a semiconductor package in which a semiconductor chip, a conductive wire, and an inner lead on a sink are encapsulated with an encapsulant, The adhesive tape positioned on the upper surface of the heat sink around the semiconductor chip is bonded to the outside of the bonding region of the inner lead to which the wire is connected. The semiconductor package according to claim 1, wherein the inner lead region in contact with an end portion of the adhesive tape facing the semiconductor chip is bent at an angle so that the remaining inner lead region is in contact with the heat sink. The semiconductor package according to claim 1 or 2, wherein an upper portion of the heat sink is coated with an insulating material so that short circuits between inner leads do not occur.