Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
2002-09-19
2004-07-13
Nelms, David (Department: 2818)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C257S676000, C257S686000, C257S712000
Reexamination Certificate
active
06762490
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device and a method for producing the same.
2. Description of the Related Art
FIGS. 10 and 11
illustrate a QFP (Quad Flat Package) semiconductor device
100
, which is a typical IC package.
The semiconductor device
100
is formed by adhering a semiconductor element
104
into a die pad
102
with an adhesive, and connecting electrodes
108
of the semiconductor element
104
to Ag-plated electrodes
112
of lead frames
110
via wires
114
.
The wires
114
are connected to the electrodes
108
of the semiconductor element
104
by ball bonding (first bonding) and to the Ag-plated electrodes
112
of the lead frames
110
by wedge bonding (second bonding).
The semiconductor element
104
and the wires
114
are enclosed in a sealing resin
116
for protection against external stresses and environmental conditions.
The rows of the electrodes
108
are disposed near each edge of the upper surface of the semiconductor element
104
. Inner wires
114
B, which bond inner electrodes
108
B with the Ag-plated electrodes
112
, and outer wires
114
A, which bond outer electrodes
108
A with the Ag-plated electrodes
112
, are positioned at different heights.
Therefore, there is a risk that the inner wires
114
B and the outer wires
114
A may come into contact with each other. If the inner wires
114
B and the outer wires
114
A come into contact with each other, the semiconductor device may not function whereas signals for the respective electrodes
108
are different.
SUMMARY OF THE INVENTION
In view of the aforementioned problem, an object of the present invention is to provide a semiconductor device, wherein a member is placed between bonding wires to prevent the bonding wires from coming into contact with each other, and a method for producing the semiconductor device.
A first aspect of the present invention is a semiconductor device comprising a semiconductor element having arranged thereon rows of electrodes connected via bonding wires to electrodes of lead frames, wherein the bonding wires comprise inner bonding wires which connect to electrodes disposed at an inner side of the semiconductor element and outer bonding wires which connects to electrodes disposed at an outer side of the semiconductor element, and a member for preventing contact between the inner bonding wires and the outer bonding wires is placed on the outer bonding wires so as to be interposed between the inner bonding wires and the outer bonding wires.
Next, the operation and effects of the semiconductor device according to the first aspect are described.
The semiconductor device is provided with the inner bonding wires which connect to the electrodes disposed at the inner side of the semiconductor element and the outer bonding wires which connect to the electrodes disposed at the outer side of the semiconductor element. If the inner and outer bonding wires come into contact with each other, the semiconductor device will not function.
In the present invention, the contact prevention member is placed on the outer bonding wires so as to be interposed between the inner bonding wires and the outer bonding wires, thereby preventing the inner bonding wires and the outer bonding wires from coming into contact with each other.
Contact between the inner bonding wires and the outer bonding wires could also be prevented by providing a supporting rod between them. However, if the supporting rod is provided, a structure for fixing the supporting rod is necessary. This increases the number of production steps involved in as well as cost of producing the semiconductor device.
In the semiconductor device of the present invention, a looped contact prevention member is used instead of the supporting rod. The looped contact prevention member is stabilized merely by being placed on the outer bonding wires. Therefore, there is no need for an additional structure for fixing the contact prevention member, and increases in the number of required production steps and in production costs can be avoided.
The required strength of the outer bonding wires could present a problem since they support the contact prevention member placed thereon.
However, by forming the contact prevention member as a loop, the contact prevention member can be supported by all of the outer bonding wires when, for example, the outer bonding wires are connected to each side of the semiconductor element. Therefore, the load applied to each of the outer bonding wires is small. Thus, the required strength of the outer bonding wires can be kept from presenting a problem.
A second aspect of the present invention is a semiconductor device wherein the contact prevention member comprises a multiple loop structure and makes contact with each of the bonding wires at two or more points.
Accordingly, this structure effectively prevents the bonding wires from coming into contact with each other even when the lengths thereof are long.
A third aspect of the present invention is a semiconductor device wherein the contact prevention member has disposed on surfaces thereof protruding members for preventing mutually adjacent bonding wires from coming into contact with each other.
The protruding members formed on the contact prevention member function as guides for the wires and hold the bonding wires in their respective places. Thus, this structure prevents mutually adjacent bonding wires from coming into contact with each other.
Particularly, when a semiconductor package is sealed, the bonding wires may be pushed by a sealing resin. However, by providing the protruding members, the bonding wires can be held in their respective positions, thereby preventing mutually adjacent bonding wires from coming into contact with each other.
A fourth aspect of the present invention is a semiconductor device comprising: a semiconductor element having arranged thereon rows of electrodes; inner bonding wires for connecting electrodes disposed at an inner side of the semiconductor element and electrodes of lead frames; outer bonding wires for connecting electrodes disposed at an outer side of the semiconductor element and the electrodes of the lead frames; and a member for preventing contact between the bonding wires comprising a loop shaped base placed on the lead frames and a loop shaped supporting portion interposed between the inner bonding wires and the outer bonding wires, for supporting the inner bonding wires from below to suspend the semiconductor element and for preventing the inner bonding wires and the outer bonding wires from coming into contact with each other.
In the fourth aspect of the present invention, the contact prevention member is placed on the lead framed and on the outer bonding wires so as to be interposed between the inner bonding wires and the outer bonding wires, thereby preventing the inner bonding wires and the outer bonding wires from coming into contact with each other.
In a typical semiconductor device, a semiconductor element is disposed on a die pad in order to provide sufficient strength. However, if the die pad is provided, the semiconductor device must be thicker and this leads to an increase in the size of the semiconductor device.
If the size of the semiconductor device is increased, the size of an accommodating device, into which the semiconductor device is incorporated, must also be increased. This, in turn, increases the costs of producing the semiconductor device and the accommodating device.
In the present invention, the contact prevention member comprises the loop shaped base which is placed on the lead frames and the loop shaped supporting portion which support the inner bonding wires from below. Therefore, the semiconductor element is suspended via the inner bonding wires in this structure.
Since the supporting portion can support the weight of the semiconductor element and can also provide reinforcement, the die pad becomes unnecessary, allowing a die pad-less structure. As a result, the thickness of the semiconductor device can be reduced to m
Nelms David
Nguyen Dao H.
Oki Electric Industry Co. Ltd.
Volentine & Francos, PLLC
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