Tape carrier package having stacked semiconductor elements,...

Details Tape carrier package having stacked semiconductor elements,... Tape carrier package having stacked semiconductor elements,...

2002-04-19

2003-12-16

Williams, Alexander O. (Department: 2826)

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

Lead frame

With bumps on ends of lead fingers to connect to semiconductor

C257S666000, C257S686000, C257S685000, C257S723000, C257S684000, C257S796000, C257S698000, C257S696000, C257S777000, C174S254000, C174S261000, C174S255000, C029S846000

Reexamination Certificate

active

06664618

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tape carrier package (TCP) which is a thin semiconductor device, a fabrication method thereof, and a tape carrier.
2. Description of the Related Art
A conventional IC packaging is used for protecting an IC body from external substances and mounting on a circuit board. In recent years, because IC products have an even wider range of applications, and material, size and configuration of packages have become diversified, and as the demand to mount a larger number of pins at an even higher density has increased, the demand to add higher values to the package itself has increased even more.
One such package configuration is a TOP (tape carrier package). A tape carrier herein is a semiconductor device fabricated in the following manner. A device hole is first formed in a flexible base tape, leads (wiring patterns) are formed by, for example, photolithography, and then a solder resist is formed to protect the leads. The TOP is a package in which semiconductor elements are mounted on the tape carrier and sealed by, for example, a resin. A package in which semiconductor element(s) are mounted on a tape carrier but are not sealed by a molding is referred to as a structure.
In a conventional tape carrier, on a photographic film-like base tape made of, for example, polyimide, device holes are formed along the longitudinal direction of the base tape. Many sprocket holes are provided in the vicinity of and along the both width direction edges of the base tape so as to be parallel to the device holes, to facilitate conveyance of the base tape during manufacturing thereof, or the like. A plurality of leads is formed as inner lead portions which protrude toward each device hole. These leads are generally formed of a conductive metal, such as aluminum, copper, or the like. A solder resist is formed on the leads to protect the wiring pattern at a portion of the leads that are on the base tape. The entire surface of each of the leads is plated with Sn (tin), Au (gold), solder, or the like for protection and for bonding the leads.
To mount semiconductor elements on the tape carrier, the semiconductor elements are bonded to the inner lead portions by, for example, eutectic reaction or thermo-compression. Then, a mold is formed by a resin, or the like. Finally, the base tape is cut out to form each package. The package is surface mounted on, for example, a printed wiring board by bonding outer lead portions thereof to the printed wiring board.
A conventional TCP is shown in
FIGS. 15A and 15B
.
FIG. 15A
is a plan view of the conventional TCP and
FIG. 15B
is a sectional view of the conventional TCP taken along line C-C′ of
FIG. 15A. A
base film
101
is made of, for example, polyimide. Sprocket holes
102
are formed on the base film
101
for conveyance of the base film
101
. A semiconductor element
110
includes protruding electrodes
111
which are connected to terminals
103
via inner lead portions
105
. The terminals
103
are connected to external circuits. The inner lead portions
105
and the terminals
103
are made of copper, formed by etching and plated with Sn, Au, or solder. The terminals
103
are wider than the inner lead portions
105
. A solder resist
106
is formed on the inner lead portions
105
to protect the copper-made pattern except the terminals
103
. A sealing resin
112
is provided to cover and protect the semiconductor element
110
and the inner lead portions
105
.
Another conventional TCP is shown in
FIGS. 16A and 16B
, which is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 5-21703.
FIG. 16A
is a plan view of an IC package and
FIG. 16B
is a sectional view taken along line C-C′ of FIG.
16
A. This TCP is fabricated in the following manner. Device holes
104
are formed on a tape base
102
. Leads
108
are provided on the tape base
102
at the periphery of the device hole
104
. Several semiconductor chips
106
are stacked in the device hole
104
. Tips of the leads
108
are formed as inner lead portions
108
a
, which are connected to bumps
110
disposed on the semiconductor chips
106
. Then, the semiconductor chips
106
and the device hole
14
are sealed by, for example, a sealing resin
112
. This conventional structure has drawbacks in that, because the semiconductor chips
106
are stacked with chip surfaces on which leads
108
are to be bonded facing each other, it is necessary to overturn the package during bonding of the leads
108
. Further, because only the leads extending in opposed two directions are connected to each semiconductor chip
106
, there are limits to increasing packaging density of semiconductor chips.
For several years, an IC package, known as a BGA (i.e., ball grid array) package which can be mounted at a high density on a printed wiring board, has been developed. In the BGA package, metal balls for connecting to external circuits are disposed in a grid-like pattern at the bottom of the IC package. In this configuration, because terminals for external connection are disposed in a two-dimensional plane, the number of pins can be increased without changing the dimensions of the package very much.
FIGS. 17A and 17B
illustrate a BGA structure disclosed in JP-A No. 8-148526, which uses a tape carrier.
FIG. 17A
is a sectional elevation view, and
FIG. 17B
is a bottom view, of a BGA type IC package. The BGA semiconductor device has excellent moisture resistance property, and can be fabricated at a low cost, and can be produced in large quantities. In the BGA semiconductor device, a device hole
102
a
is formed in the center of a flexible resin substrate made of, for example, polyimide film. Leads
103
formed of a copper foil are provided at a surface of the substrate, and the substrate is used as a TCP substrate. Tips of the leads
103
are formed as inner lead portions
103
a
, which are connected to electrodes
101
a
of a semiconductor chip
101
. Each lead
103
is connected to a corresponding bump
105
, such as a solder ball disposed at the bottom surface of the package.
In such conventional tape carriers, only one semiconductor element can be mounted on a single tape carrier, and it is difficult to mount several semiconductor elements, particularly semiconductor elements having different sizes, on a single tape carrier at a high density to improve functions of the semiconductor package.
In the package configuration which employs a combination of the tape carrier and the BGA, a larger number of external terminals may be extended from a package of the same size as those of conventional ones. However, it is very difficult to improve functions of the package itself by densely mounting several semiconductor elements on a single tape carrier.
SUMMARY OF THE INVENTION
In view of the aforementioned, an object of the present invention is to improve functions of and to add further values to a semiconductor package by mounting several semiconductor elements (particularly semiconductor elements of different sizes) in a single device hole of a tape carrier without losing TCP advantages of being compact and thin.
A semiconductor package of the present invention comprises: a tape carrier; a first semiconductor element having a surface and a first electrode, on which surface the first electrode is provided; a longer lead which is provided on the tape carrier and connected to the first electrode; a second semiconductor element having a surface and a second electrode, on which surface the second electrode is provided, and the first semiconductor element is stacked; a shorter lead which is provided on the tape carrier and connected to the second electrode and is shorter than the longer lead; and a resin material which seals the first semiconductor element, the second semiconductor element, the longer lead and the shorter lead.
In this structure, two semiconductor elements can be stacked and accommodated in a single TCP and the semiconductor device can be made thinner. Therefore, functions of the TCP can be improved

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