Semiconductor device

Details Semiconductor device Semiconductor device

2002-04-26

2003-11-18

Potter, Roy (Department: 2822)

Active solid-state devices (e.g., transistors, solid-state diode

Lead frame

C257S676000, C257S692000

Reexamination Certificate

active

06650004

ABSTRACT:

TECHNICAL FIELD
This invention relates to a surface mount type semiconductor device usable as a diode, transistor and so on.
BACKGROUND ART
Up to now, surface mount type semiconductor devices have been proposed to be used as diodes, transistors and so on. One example of such semiconductor devices is shown in
FIG. 16
to
FIG. 18
of the accompanying drawings. The semiconductor device S may be a transistor, comprising an internal lead
91
as a base terminal, an internal lead
92
as a collector terminal, and an internal lead
93
as an emitter terminal.
The internal terminals
91
,
92
and
93
are juxtaposed and are flush with one another. A substantially rectangular island
94
is formed at one end of the internal lead
91
. A semiconductor chip
95
(also called a “pellet”) is die-bonded onto the island
94
using a gold wire W or the like, and is electrically connected to the internal leads
92
and
93
. The semiconductor chip
95
, gold wire W and internal leads
91
-
93
are housed in a resin package
97
made of thermosetting epoxy resin or the like. The internal leads
91
to
93
are folded and are respectively connected to external leads
11
to
13
on the outer surface of the resin package
97
.
The semiconductor chip
95
generates heat as the semiconductor device S is operated. Especially, if the semiconductor device S is used as a power transistor, the generated heat should be efficiently radiated to the exterior of the resin package
97
in order to assure reliable operation of the semiconductor chip
95
.
With the semiconductor device S, the semiconductor chip
95
is mounted on the island
94
, which functions as a radiator for dissipating heat via the internal lead
91
or via the resin package
97
in contact with the internal lead
91
. In this case, the island
94
preferably has a large upper surface area in order to promote heat radiation. Further, there has been a demand to enlarge the semiconductor chip
95
in order to improve the performance of electronic circuits integrated therein. Therefore, the island
94
is required to have a large upper surface area.
In order to increase the plane area of the island
94
, it is conceivable to make the internal leads
92
and
93
juxtaposed on the island
94
smaller. However, both the island
94
and the internal leads
92
and
93
are positioned to be substantially flush with one another so that they are connected by gold wires W or the like. Naturally it is impossible to enlarge the island
94
without limit. At present, the upper surface area of the internal lead
91
occupies approximately 40% of the area of base of the resin package
97
at the most. As a result, it has been requested to increase the foregoing occupancy ratio in order to promote heat radiation.
DISCLOSURE OF THE INVENTION
It is an object of the invention to provide a semiconductor device which can overcome the foregoing problems of the related art or at least reduce those problems.
According to a first aspect of the invention, there is provided a semiconductor device comprising: a semiconductor chip; a chip-mounting internal lead having the semiconductor chip mounted thereon; chip-connecting internal leads which are electrically connected to an upper surface of the semiconductor chip; and a rectangular resin package which houses the semiconductor chip and the internal leads. In the semiconductor device, the chip-mounting internal lead includes one end which is rectangular or substantially rectangular along the length of the resin package.
An upper surface area of the chip-mounting lead is preferably equal to or larger than approximately 50% of an area of base of the resin package.
In this arrangement, the semiconductor device has a so-called wireless structure in which the chip-connecting internal leads are connected to the upper surface of the semiconductor chip on the chip-mounting internal lead. One end of the chip-mounting internal lead is rectangular or substantially rectangular along the length of the rectangular resin package. The upper surface area of the chip-mounting internal lead can be increased as desired. Therefore, heat generated by the semiconductor chip can be dissipated outward via the enlarged chip-mounting internal lead or via the resin package in contact with the chip-mounting internal lead. This improves the heat radiation of the semiconductor device. Further, the chip-connecting internal leads are directly connected to the semiconductor chip. For this reason it is possible to dissipate heat from the semiconductor chip through the chip-connecting internal leads, which contributes to improvement of heat radiation.
In a preferred embodiment of the invention, the semiconductor chip is mounted at the center of the chip-mounting internal lead extending along the length of the resin package.
In this arrangement, heat generated by the semiconductor chip is radiated widely along the length of the resin package (to the right and left) via the chip-mounting internal lead, compared with a case where the semiconductor chip is eccentrically mounted on the chip-mounting internal lead.
With a further preferred embodiment of the invention, a width of a non-end portion of the chip-mounting lead is equal to a width of the end.
This structure promotes heat radiation from the chip-mounting lead to the exterior.
According to a second aspect of the invention, there is provided a semiconductor device comprising: first and second semiconductor chips; first and second chip-mounting internal leads having the first and second semiconductor chips, respectively, mounted thereon; a plurality of chip-connecting internal leads which are electrically connected to upper surfaces of the first and second semiconductor chips; and a rectangular resin package housing the first and second semiconductor chips and the first and second internal leads. Each of the first and second chip-mounting internal leads includes one end which is rectangular or substantially rectangular along the length of the resin package.
It is preferable that an upper surface area of each end of the chip-mounting leads is equal to or larger than approximately 50% of an area of base of the resin package.
When a plurality of semiconductor chips are provided in the resin package, the chip-mounting internal leads for the semiconductor chips have ends thereof which are rectangular or substantially rectangular along the length of the resin package. The semiconductor device of the second aspect can have the wireless structure similarly to that of the first aspect. Therefore, the upper surface area of each end of the chip-mounting internal leads can occupy approximately 50% or more of the area of the base of the resin package. This is effective in dissipating heat generated by the semiconductor chips to the exterior of the semiconductor device.
In a still further embodiment, ends of the first and second chip-mounting internal leads are positioned to be flush with each other, so that the first and second semiconductor chips are juxtaposed in the resin package.
When a plurality of semiconductor chips are juxtaposed to be flush with one another, the semiconductor device can have a large upper surface area. However, the wireless structure effectively suppresses the enlargement of the upper surface area of the semiconductor device even when the semiconductor chips are juxtaposed in the resin package. This can substantially downsize the semiconductor device.
In a further embodiment of the invention, one end of either the first or second chip-connecting internal lead extends over the two upper surfaces of the first and second semiconductor chips, to thereby connect these upper surface together.
The ends of the chip-mounting internal leads are positioned to be flush with one another, which enables the semiconductor chips to be juxtaposed. This means that the upper surfaces of the semiconductor chips are positioned on the chip-mounting internal leads, so that the chip-connecting internal leads can extend over the upper surface of the semiconductor chips, and the upper surfaces of the semiconduc

Affiliated with

Also associated with

Rating

Semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3166697