Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
1998-02-24
2003-08-19
Talbott, David L. (Department: 1763)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C257S691000, C257S666000, C257S690000
Reexamination Certificate
active
06608368
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a semiconductor device.
2. Description of Related Art
In recent years, semiconductor devices in which a flexible circuit substrate and a semiconductor chip are coupled to one another and sealed by resin are used. A method of lowering the power source impedance of such a semiconductor device and reducing electrical noise is described, for example, in Japanese Laid-open Patent Application HEI 5-82585 at column 9 and FIG. 2 thereof. The conventional structure of the semiconductor device will be described below with reference to FIG.
9
.
A semiconductor chip
1
has a plurality of signal pads (signal electrodes)
4
, power source pads (power source electrodes)
7
and grounding pads (grounding electrodes)
9
provided on an active surface of the chip
1
. These pads are treated with a bump forming process. A TAB tape
2
defines a device hole
5
, and has a plurality of signal leads
3
protruding into the device hole
5
, and a power source common lead
6
and a grounding common lead
8
extending across the device hole
5
. The signal leads
3
are electrically, directly connected to predetermined ones of the signal pads
4
Further, the power source common lead
6
is electrically, directly connected to all of the plurality of power source pads
7
, and the grounding common lead
8
is also electrically, directly connected to all of the plurality of grounding pads
9
. The leads
3
,
6
and
8
and the pads
4
,
7
and
9
are electrically connected by a package connecting method using heat and pressure.
However, in the above-described conventional semiconductor device, each of the power source common lead and the grounding common lead is narrower than the width of each of the bumps formed for the power source pads and the grounding pads, and therefore the power source impedance cannot be sufficiently reduced. Furthermore, when these common leads are electrically connected to the corresponding pads by heat-and-pressure bonding, stress is generated by the heat and the pressure applied to the common leads. As a result, cracks are likely generated in the common leads, and the cracks may develop after the device is assembled in an electronic device and may eventually result in the snapping of the common leads.
Also, when an electronic device is provided with the conventional semiconductor device, the power source impedance cannot be sufficiently lowered. As a result, the electronic device with high-frequency operation or with high current consumption is suffered from problems in which electrical noise cannot be improved. Moreover, since line-breaking problems are likely to occur in the power source line and the grounding line, it is difficult to secure long-term reliability.
Also, in the above-described semiconductor device, the power source common lead
6
and the grounding common lead
8
, that protrude into the device hole
5
of the TAB tape
2
, are supported only by their own ends, respectively. As a result, the leads
6
and
8
slacken by their own weight, and therefore, positioning of the leads with respect to the power source pads
7
and the grounding pads
9
is difficult.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a semiconductor device which has a sufficiently low power source impedance, and eliminates line-snapping problems that may occur in a power source common lead and a grounding common lead.
Furthermore, it is another object of the present invention to facilitate positioning of a power source common lead or a grounding common lead with respect to power source electrodes or grounding electrodes, respectively.
It is also another object of the present invention to provide an electronic device that reduces electrical noise and assures a long-term reliability.
To achieve the above-described objects, a semiconductor device of a first aspect of the present invention is formed, for example, from a semiconductor chip, a circuit substrate including a flexible insulation substrate and conductor patterns formed thereon, and sealing resin. The conductor patterns that protrude into an opening defined in the flexible insulation substrate are coupled to the semiconductor chip, and the coupling section is sealed by the sealing resin. It is preferred that at least one of the conductor patterns is formed to extend across the opening and has a specified width wider than a pad for connecting to the semiconductor chip.
In accordance with the invention thus structured, the conductor pattern that defines a common lead extending across the opening has a width wider than the pad for connecting to the semiconductor chip. As a consequence, the current carrying capacity is increased and the power source impedance is substantially lowered.
In a semiconductor device of a second aspect of the present invention, the conductor pattern formed to extend to across the opening preferably has a bent section at least one location.
In accordance with this embodiment, the bent section reduces the stress generated in the conductor pattern when it is electrically connected to the corresponding pads so that generation of cracks in the conductor pattern can be prevented. Consequently, it is effective in preventing the line-snapping resulting from cracks which may grow after assembled in an electronic device.
An electronic device of a third aspect of the present invention includes a semiconductor device as described above, and one of a display device, a printing device and a computer device which is driven by the semiconductor device
In accordance with the above-described invention, the power source impedance is substantially lowered and the electrical noise is improved because of the provision of a semiconductor device set forth in the first aspect. Also, the line-snapping of the power source line is eliminated and a substantially long-term reliability is secured because of the provision of a semiconductor device set forth in the second aspect.
A semiconductor device of a fourth aspect of the present invention is preferably formed from a semiconductor chip, a circuit substrate including a flexible insulation substrate and conductor patterns formed thereon, and sealing resin. The conductor patterns that protrude into an opening defined in the flexible insulation substrate are coupled to the semiconductor chip, and the coupling section is sealed by the sealing resin. It is preferred that at least one of the conductor patterns is formed to extend across the opening and has at least one or more connection branch, wherein the connection branch has a specified width narrower than a pad for connecting to the semiconductor chip.
In accordance with the above-described invention, the connection branch branching out the conductor pattern and having a width narrower than the pad is used to electrically connect the pad to the conductor pattern. As a result, the width of the conductor pattern can be made wider without making the post-connection examination difficult, and therefore the power source impedance can be substantially lowered.
In a semiconductor device of a fifth aspect of the present invention, the conductor pattern formed to extend across the opening in the semiconductor device described above preferably has a specified width wider than the pad. As a result, the current carrying capacity of the conductor pattern is made larger and the power source impedance is substantially lowered.
In a semiconductor device of a sixth aspect of the prevent invention, the conductor pattern formed to extend across the opening in the semiconductor device set forth above preferably has a bent section at least one location thereof. This results in the same effect obtained by the invention set forth in the second aspect.
An electronic device of a seventh aspect of the present invention preferably includes a semiconductor device described above, and one of a display device, a printing device and a computer device which is driven based on the semiconductor device. In accordance with this invention, the power sourc
Oliff & Berridg,e PLC
Seiko Epson Corporation
Talbott David L.
Thai Luan
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