JPH1056032A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation and the like of wire and the occurrence of deflective connection, by constituting the device by lowering a die pad in the direction of the rear surface of the connecting surface so that the heights of a bonding wire ball is as high as the inner lead at the surface where the inner lead and the bonding wire are connected, become equal. SOLUTION: A die pad 4 is constituted by lowering the pad in the direction of the rear surface of the surface, where an inner lead 6 and a bonding wire 3 are connected, so that the height of the upper surface of the inner lead 6 at the surface, where the inner lead 6 and the bonding wire 3 are connected, agrees with the height of the upper surface of the bonding wire ball 3. Thus, the bonding wire 3 and the end part on the side of a semiconductor chip 1 on the side of the inner lead 6 do not become contact. That is to say, the trouble, wherein the electrode of the semiconductor chip 1, to which the bonding wire 3 is connected, and the semiconductor chip are electrically short-circuited and the inconvenience that the function required for the semiconductor chip 1 is not normally operated, does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor chip,
The present invention relates to a configuration of a semiconductor device electrically connected to a lead frame using a bonding wire.

[0002]

2. Description of the Related Art The structure of a conventional semiconductor device is shown in a sectional view of FIG. As shown in FIG.
A lead frame 5 having the semiconductor chip 1 attached thereto, inner leads 6, bonding wires 3, bonding wire balls 2, and molding resin 7. Generally, the die pad 4 is configured so as to be lowered in the back surface direction of the surface where the inner lead 6 and the bonding wire 3 are connected.

In such a structure, an electrode (not shown in FIG. 2) of the semiconductor chip 1 and an inner lead 6 are connected to a bonding wire 3 by a wire bonding apparatus.
This is performed in order to prevent a problem in which the bonding wire 3 and the end of the semiconductor chip 1 come into contact with each other when making an electrical connection.

FIG. 11 is a cross-sectional view showing a state where the bonding wire 3 and the end of the semiconductor chip 1 have come into contact with each other. As shown in FIG. 11, a lead frame 5 having a semiconductor chip 1 attached to a die pad 4
, Inner lead 6, bonding wire 3,
It comprises a bonding wire ball 2 and a mold resin 7.

The lead frame 5 has a surface on which the inner leads 6 are connected to the bonding wires 3 and a surface on which the semiconductor chip 1 is adhered is located on the same surface. The semiconductor chip 1 is attached to the die pad 4 of the lead frame 5 using a silver paste (not shown in FIG. 11).

Next, the inner leads 6 and the semiconductor chip 1 are electrically connected by bonding wires 3 using a wire bonding apparatus.

[0007]

However, at this time, the height of the upper surface of the semiconductor chip 1 on the side where the bonding wire 3 and the semiconductor chip 1 are connected is equal to the bonding wire 3.
Inner lead 6 on the side where the inner lead 6 is connected to
Above the upper surface of the semiconductor chip 1 from the die pad 4.

As a result, as shown in FIG. 11, a problem that the bonding wire 3 comes into contact with the end of the semiconductor chip 1 is likely to occur.

When the bonding wire 3 comes into contact with the end of the semiconductor chip 1 as described above, the electrode (FIG. 1) of the semiconductor chip 1 to which the bonding wire 3 is connected.
1 (not shown) and the end of the semiconductor chip 1 are electrically connected, and an electrical short circuit occurs. When such an electrical short-circuit occurs, a problem occurs that a function required for the semiconductor chip 1 does not operate normally.

As shown in FIGS. 2 and 11, the height of the upper surface of the bonding wire ball 2 on the side of the bonding wire 3 and the height of the upper surface of the inner lead 6 on the side where the bonding wire 3 and the inner lead 6 are connected are determined. Are different from each other, there is a problem that deformation of the bonding wire ball 2, deformation of the boundary between the bonding wire ball 2 and the bonding wire 3, or cutting may occur. Furthermore, there is a problem that a connection failure between the inner lead 6 and the bonding wire 3 may occur.

It is an object of the present invention to solve the above-mentioned problems and to provide a semiconductor device which does not cause deformation or cutting of a wire due to wire bonding or poor connection with an inner lead.

[0012]

Means for Solving the Problems To achieve the above object, the semiconductor device of the present invention employs the following configuration.

A semiconductor device according to the present invention includes a die pad, a semiconductor chip, a lead frame, and a molding resin. The upper surface of the inner lead is connected to the inner lead and the bonding wire. The die pad is lowered toward the back surface of the surface where the inner lead and the bonding wire are connected so that the height is the same.

In the semiconductor device according to the present invention, the upper surface of the inner lead on the side where the bonding wire and the inner lead are connected is the same as the upper surface of the bonding wire ball on the bonding wire side. Are lowered from the semiconductor chip toward the die pad.

Further, in the semiconductor device according to the present invention, the inner leads to which the bonding wires are connected are so arranged that the upper surface of the inner leads at the surface where the inner leads and the bonding wires are connected and the upper height of the bonding wire balls are substantially the same. Is thicker than the thickness of the inner lead other than the tip.

[Operation] Therefore, in the semiconductor device according to the present invention, in the electrical connection between the semiconductor chip and the inner lead, the bonding wire does not come into contact with the end of the semiconductor chip. The electrodes of the semiconductor chip and the ends of the semiconductor chip are not electrically short-circuited. For this reason, the problem that the function required for the semiconductor chip does not operate properly does not occur.

Further, in the semiconductor device according to the present invention, in the electrical connection between the semiconductor chip and the inner lead, there is no deformation or cutting of the bonding wire at the boundary between the bonding wires.

Further, in the semiconductor device according to the present invention,
No connection failure between the bonding wire and the inner lead occurs. For this reason, the cutting strength at the connection between the inner lead and the bonding wire, or the cutting strength at the connection between the semiconductor chip and the bonding wire ball, or the pull strength at the boundary between the bonding wire and the bonding wire ball Can be increased.

[0019]

Preferred embodiments for implementing a semiconductor device of the present invention will be described below with reference to the drawings. A configuration of a semiconductor device according to an embodiment for implementing the present invention will be described with reference to FIG. FIG. 1 is a sectional view showing a semiconductor device of the present invention.

[Description of Semiconductor Device: FIG. 1] As shown in FIG. 1, a lead frame 5 in which a semiconductor chip 1 is bonded to a die pad 4, an inner lead 6, and a semiconductor chip 1
And a bonding wire 3 for connecting the bonding wire ball 2 to the inner lead 6. For the lead frame 5, a material of a 42% Ni-Fe alloy is used. Further, a mold resin 7 for covering the semiconductor chip 1 and the bonding wires 3 is provided.

Further, the surface of the inner lead 6 on the side where the bonding wire 3 is connected to the inner lead 6 and the surface of the die pad 4 on the side where the semiconductor chip 1 is adhered are plated with silver. The semiconductor chip 1 is attached to the die pad 4 of the lead frame 5 using a silver paste (not shown in FIG. 1).

Next, the inner leads 6 and the semiconductor chip 1 are electrically connected by bonding wires 3 using a wire bonding apparatus. As the bonding wire 3, a gold (Au) wire having a purity of 99.99% or more is used. In the present invention, a wire having a diameter of 30 μmφ was used.

Next, a molding resin 7 is formed by a transfer molding method, and the semiconductor chip 1, the die pad 4, the inner leads 6, the bonding wires 3, and the bonding wire balls 2 are sealed. An epoxy resin for semiconductor encapsulation is used as the mold resin 7.

[Description of Electrical Connection Method of Semiconductor Device: FIGS. 3 to 6] The electrical connection method of the semiconductor device according to the present invention using the wire bonding apparatus will now be described with reference to FIGS.
This will be described with reference to FIG. As shown in FIG. 3, the capillary 31 for a wire bonding apparatus is inserted into a capillary mounting hole 37 penetrating a transducer 32 of the wire bonding apparatus, and is fixed by a capillary mounting bolt 38.

Capillary 3 for wire bonding equipment
A bonding wire hole 39 penetrates the center of 1 and a bonding wire 36 penetrates. Electric torch 33 and capillary 31 for wire bonding equipment
When electric discharge is performed between the bonding wire 36 and the bonding wire 36 protruding from the front end portion 35, a bonding wire ball 34 is formed at the front end of the bonding wire 36.

Next, as shown in FIG. 4, the capillary 31 for the wire bonding apparatus is lowered, and the bonding wire ball 34 is pressed against the electrode 42 provided on the semiconductor chip 1 which has been heated in advance.

Then, as shown in FIG. 5, the capillary 31 for the wire bonding apparatus is moved to the pre-heated inner lead 52. At this time, the bonding wire 36 is paid out from the bonding wire hole 39 penetrating the distal end portion 35 of the capillary 31 for the wire bonding apparatus.

Capillary 3 for wire bonding equipment
1 presses the bonding wire 36 to the inner lead 52. After the bonding of the bonding wire 36 and the inner lead 52 is completed, the capillary 31 for a wire bonding apparatus is raised as shown in FIG. 6, and the bonding wire 36 is cut off from the inner lead.

In this series of operations, in the semiconductor device according to the present invention, as shown in FIG. 1, the upper surface height of the inner lead 6 where the inner lead 6 and the bonding wire 3 are connected, and the height of the bonding wire ball 2 The inner lead 6 should be at the same height as the upper part.
The die pad 4 is lowered in the direction of the back surface of the surface where the bonding wire 3 and the bonding wire 3 are connected.

As a result, the bonding wire 3
And the end on the inner lead 6 side of the semiconductor chip 1 does not come into contact with each other. That is, bonding wire 3
The electrodes (not shown in FIG. 1) of the semiconductor chip 1 to which the electrodes are connected and the ends of the semiconductor chip 1 are electrically connected to each other, causing an electrical short circuit. The malfunction of not operating properly does not occur.

In the method of electrically connecting a semiconductor device according to the present invention using the wire bonding apparatus described above with reference to FIGS. 3 to 6, the raising and lowering operations of the wire bonding apparatus capillary 31 in this series of operations are described. However, the vertical and vertical movements with respect to the electrodes 42 and the inner leads 52 are not complete.

[Explanation of Capillary for Wire Bonding Apparatus: FIG. 7] As shown in FIG. 7 (a), the position of the capillary 31 for wire bonding apparatus is raised, and as shown in FIG. The operation up to the position when the use capillary 31 is lowered is an arc-shaped operation centered on the shaft 71 supporting the transducer 32.

That is, when the capillary 31 for the wire bonding apparatus is lowered to the electrode 42 in FIG. 4 or the inner lead 52 in FIG. 5, for example, only one point where the electrode surface is perpendicular to the capillary 31 for the wire bonding apparatus.

However, as shown in FIG. 1, in the semiconductor device according to the present invention, the upper surface of the inner lead 6 where the inner lead 6 and the bonding wire 3 are connected, and the upper height of the bonding wire ball 2 are different. The die pad 4 is lowered toward the back surface of the surface where the inner lead 6 and the bonding wire 3 are connected so as to be the same.

As a result, the bonding wire ball 2 is vertically pressed on the semiconductor chip 1 by a capillary. Therefore, the deformation of the bonding wire ball 2 at the time of the press bonding, the deformation of the boundary between the bonding wire ball 2 and the bonding wire 3, or the cutting does not occur.

Similarly, the bonding wire 3 is vertically pressed to the inner lead 6 by a capillary. Therefore, a connection failure between the inner lead 6 and the bonding wire 3 does not occur.

[Description of Method of Measuring Pull Strength of Bonding Wire: FIGS. 12 to 14] A method of measuring the pull strength of a bonding wire will be briefly described with reference to FIGS. As shown in FIG. 12, a bonding wire 3 electrically connecting the semiconductor chip 1 and the inner lead 6 is connected to a hook 14 provided on the load sensor 13.
Hook.

Next, as shown in FIG. 13, the load is applied to the bonding wire 3 by pulling up the load sensor 13 in the direction of the arrow shown in FIG. When the load sensor 13 is further pulled up in the direction of the arrow shown in FIG. 13, the bonding wire 3 is finally cut as shown in FIG. The value of the load indicated by the load sensor 13 at this time is the cutting strength of the bonding wire 3, that is, the pull strength. FIG. 14 shows a state of cutting at the boundary between the bonding wire ball 2 and the bonding wire 3.

As described above, when the bonding wire ball 2 is vertically pressed against the semiconductor chip 1 by the capillary, the bonding wire ball 2 is not deformed. Further, no deformation occurs at the boundary between the bonding wire ball 2 and the bonding wire 3.

Similarly, when the bonding wire 3 is vertically pressed against the inner lead 6 by a capillary,
No connection failure between the bonding wire 3 and the inner lead 6 occurs.

Thus, the pull strength at the connection between the bonding wire ball 2 and the semiconductor chip 1, the pull strength at the connection between the bonding wire ball 2 and the bonding wire 3, or the bonding strength between the bonding wire 3 and the inner lead 6 is obtained. And the pull strength at the connection with the wire increases.

[Explanation of Measurement Results of Pull Strength: FIG. 10] Graphs 1 and 2 in FIG. 10 are graphs showing measured values of the pull strength of the semiconductor device according to the present invention. The measurement of the pull strength of 12 bonding wires for one sample to be measured was performed for two samples to be measured. As a result, a pull strength of 11.8 [g] was obtained in both samples on average.

Graphs 3 and 4 in FIG. 10 are graphs showing measured values of the pull strength of the conventional semiconductor device. As with the pull strength measurement of the semiconductor device according to the present invention,
The measurement of the pull strength of 12 bonding wires for one sample to be measured was performed for two samples to be measured. As a result, the pull strengths were 6.5 [g] and 6.4 [g] on average, respectively.

As is clear from the results shown in FIG. 10, the semiconductor device according to the embodiment of the present invention has achieved a significant improvement in pull strength.

[Description of Another Embodiment: FIG. 8] FIG. 8 is a sectional view showing another embodiment of the semiconductor device according to the present invention. It comprises a lead frame 5 in which the semiconductor chip 1 is attached to the die pad 4, inner leads 6, bonding wires 3, bonding wire balls 2, and molding resin 7.

The upper surface of the inner lead 6 at the surface where the inner lead 6 and the bonding wire 3 are connected and the upper height of the bonding wire ball 2 on the bonding wire 3 side are the same.
The inner lead 6 is raised in the direction of the surface to be connected with the bonding wire 3.

The method of manufacturing the semiconductor device of FIG. 8 according to the present invention is the same as the method of manufacturing a semiconductor device configured by lowering the die pad described above.

Also, as shown in FIG.
The surface where the inner lead 6 and the bonding wire 3 are connected such that the upper surface height of the inner lead 6 at the surface where the bonding wire 3 is connected and the upper height of the bonding wire ball 2 at the side of the bonding wire 3 are the same. The inner lead 6 is raised in the direction of. For this reason, the inner lead 6 and the bonding wire 3 are vertically pressed by a capillary, and similarly, the semiconductor chip 1 and the bonding wire ball 2 are vertically pressed by a capillary.

Therefore, the deformation of the bonding wire ball 2 at the time of the pressure bonding, the deformation of the boundary between the bonding wire ball 2 and the bonding wire 3 and the cutting are not generated. Similarly, a connection failure between the inner lead 6 and the bonding wire 3 does not occur.

Therefore, in the semiconductor device according to the present invention, the deformation and cutting of the wire due to the wire bonding and the connection failure with the inner lead do not occur as compared with the semiconductor device of the prior art.

[Explanation of Still Another Embodiment: FIG. 9] FIG. 9 is a sectional view showing another embodiment of the semiconductor device according to the present invention. It comprises a lead frame 5 in which the semiconductor chip 1 is attached to the die pad 4, inner leads 6, bonding wires 3, bonding wire balls 2, and molding resin 7.

The bonding wire 3 is connected such that the upper surface of the inner lead 6 at the surface where the inner lead 6 and the bonding wire 3 are connected is the same as the upper height of the bonding wire ball 2 on the bonding wire 3 side. The thickness of the tip of the inner lead 6 is configured to be larger than the thickness of the inner lead 6 other than the tip.

The method of fabricating the semiconductor device of FIG. 9 according to the present invention is the same as the method of fabricating the semiconductor device constructed by lowering the die pad described above.

Further, as shown in FIG.
The tip of the inner lead 6 to which the bonding wire 3 is connected so that the upper surface height of the inner lead 6 at the surface to which the bonding wire 3 is connected is equal to the upper height of the bonding wire ball 2 at the bonding wire 3 side. The thickness of the inner lead 6 other than the tip is larger than the thickness of the inner lead 6. For this reason, the inner lead 6 and the bonding wire 3 are vertically pressed by a capillary, and similarly, the semiconductor chip 1 and the bonding wire ball 2 are vertically pressed by a capillary.

Therefore, the deformation of the bonding wire ball 2 at the time of the pressure bonding, the deformation of the boundary between the bonding wire ball 2 and the bonding wire 3 and the cutting are not generated. Similarly, a connection failure between the inner lead 6 and the bonding wire 3 does not occur.

Therefore, in the semiconductor device according to the present invention, the deformation and cutting of the wire due to the wire bonding and the connection failure with the inner lead do not occur as compared with the semiconductor device of the prior art.

[0057]

As apparent from the above description, in the semiconductor device according to the present invention, the height of the upper surface of the inner lead at the surface where the inner lead and the bonding wire are connected,
The bonding wire ball is configured to have the same upper surface height.

Therefore, in the electrical connection between the semiconductor chip and the inner lead according to the present invention, the deformation of the bonding wire ball and the deformation or cutting of the bonding wire at the boundary between the bonding wire and the bonding wire ball do not occur.

Further, no defective connection between the bonding wire and the inner lead occurs. Therefore, in the semiconductor device of the present invention, an increase in pull strength can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a semiconductor device according to a conventional technique.

FIG. 3 is a side view showing the structure of the wire bonding apparatus and explaining its operation.

FIG. 4 is a side view showing the structure of the wire bonding apparatus and explaining its operation.

FIG. 5 is a side view showing the structure of the wire bonding apparatus and explaining its operation.

FIG. 6 is a side view showing the structure of the wire bonding apparatus and explaining its operation.

FIG. 7 is a side view showing a capillary structure for a wire bonding apparatus of the wire bonding apparatus and explaining its operation.

FIG. 8 is a cross-sectional view illustrating a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 10 is a graph showing a comparison between the pull strength of the semiconductor device according to the embodiment of the present invention and the pull strength of the conventional semiconductor device.

FIG. 11 shows a structure of a semiconductor device according to the related art;
FIG. 3 is a cross-sectional view for explaining a problem with electrical wiring.

FIG. 12 is a side view for explaining a method of measuring the pull strength of a bonding wire.

FIG. 13 is a side view for explaining a method of measuring the pull strength of a bonding wire.

FIG. 14 is a side view for explaining a method of measuring the pull strength of a bonding wire.

[Explanation of symbols]

 Reference Signs List 1 semiconductor chip 2 bonding wire ball 3 bonding wire 4 die pad 6 inner lead

Claims (4)

[Claims] 1. A semiconductor device comprising a die pad, a semiconductor chip, a lead frame, a bonding wire, and a molding resin, wherein an upper surface height of an inner lead is approximately equal to an upper height of a bonding wire ball. Semiconductor device. 2. A semiconductor device comprising a die pad, a semiconductor chip, a lead frame, a bonding wire, and a molding resin, wherein the upper surface of the inner lead and the upper height of the bonding wire ball at the surface where the inner lead and the bonding wire are connected. Is a semiconductor device characterized in that a die pad is lowered toward a back surface of a surface where an inner lead and a bonding wire are connected so as to be substantially the same. 3. A semiconductor device comprising a die pad, a semiconductor chip, a lead frame, a bonding wire, and a molding resin, wherein the upper surface of the inner lead and the upper height of the bonding wire ball are connected to each other. A semiconductor device characterized in that the inner lead is raised in the direction of the surface where the inner lead and the bonding wire are connected so as to be substantially the same. 4. A semiconductor device comprising a die pad, a semiconductor chip, a lead frame, a bonding wire, and a molding resin, wherein an upper surface height of the inner lead and a top height of the bonding wire ball at a surface where the inner lead and the bonding wire are connected. Wherein the thickness of the tip of the inner lead to which the bonding wire is connected is greater than the thickness of the inner lead other than the tip so that the bonding wires are substantially the same.