Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
2000-02-28
2002-01-29
Williams, Alexander O. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C257S669000, C257S662000, C257S666000, C257S672000, C257S678000, C257S673000, C257S797000, C257S674000, C257S670000, C257S727000, C361S813000
Reexamination Certificate
active
06342727
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a tape carrier for TAB for mounting an integrated circuit component, an integrated circuit device packaged with an integrated circuit component mounted therein, a method of making the same, and an electronic device.
2. Description of Related Art
Recent liquid crystal display devices use an integrated circuit device having a driver integrated circuit component mounted thereon for the purpose of connecting the LCD cell to its driver circuit. Such an integrated circuit device generally adopts either the TAB method using a so-called TAB package (also known as a TCP (Tape Carrier Package)), or the COG (Chip On Glass) method in which the driver integrated circuit component is directly connected to the glass substrate. Particularly a TAB package has many advantages, being more compact and thinner than other packages, and appropriate for high-density mounting, allowing electrical testing on a tape carrier, and also permitting mounting in a flexed position; for these reasons it has been widely adopted not only for liquid crystal display devices, but also for other electronic devices.
A conventional TAB package, as shown in
FIG. 14
, has a tape carrier
131
formed of polyimide or the like, in which is formed a device hole
133
of dimensions larger than the dimensions of an integrated circuit component
132
to be mounted thereon. Inner leads
134
projecting within the device hole
133
are connected by way of bumps
135
to electrodes of the integrated circuit component
132
. Moreover, to prevent short-circuits between inner leads
134
or contact of the inner leads
134
with the integrated circuit component
132
, and to improve reliability, a protective resin
136
covers the inner leads
134
and the surface of the integrated circuit component
132
. The electrodes and bumps
135
are normally disposed along the periphery of the integrated circuit component
132
, in order that the lengths of the inner leads
134
are as short as possible in the one-sided holding state (that is, in the state where one side only of the inner leads
134
is supported by the tape carrier
131
). Additionally, as disclosed in Japanese patent Application Laid-Open No. 63-95639, a construction is also known in which in order to mount an integrated circuit component of large scale and having a large number of electrodes, a lead support portion extending into the device hole is provided on the tape carrier, and some of the leads extend thereover.
However, a conventional TAB package as described above has a gap between the peripheral edges forming the device hole
133
and the peripheral edges of the integrated circuit component
132
, and the protective resin
136
is provided in order not to expose the inner leads
134
in this gap. As a result, the outer dimensions of the package are considerably larger than the outer dimensions of the integrated circuit component
132
and the mounting area is increased. Additionally, with the miniaturization of the integrated circuit component
132
, and a closer pitch for the electrodes and inner leads
134
, connecting leads
134
a
supported on the tape carrier
131
are required to be finer, and a large area is required to bring out the connecting leads
134
a
since the wiring distance is increased. For this reason, the area of tape carrier used for mounting a single integrated circuit component
132
is increased, the overall package dimensions are further increased, and the mounting area is increased, resulting in a problem of going against the requirement to make the electronic apparatus more compact.
In particular, in the case of a liquid crystal display, as shown in
FIG. 15
, a plurality of TAB packages
138
(only one of which is shown in the figure), each having a driver integrated circuit component
137
mounted thereon, is connected along the periphery of an LCD cell
139
, and further on the outer side thereof is connected a printed circuit board
140
forming a drive circuit. With respect to the overall dimensions of the liquid crystal display device, to increase the liquid crystal display area, it is necessary to reduce the width W of the so-called frame portion. For this purpose, it is necessary, while reducing each of the width w
1
of the outer periphery
141
of the LCD cell
139
connected to the TAB package
138
and the width w
2
of the printed circuit board
140
, to make the TAB package
138
smaller, and thus to reduce its width w
3
. For this purpose, it is possible first to consider making the driver integrated circuit component
137
smaller, and reducing the corresponding width as much as possible, but in a TAB package of the above-described conventional construction, it is difficult to go smaller than the current size, and there is a problem that the width W of the frame portion cannot be adequately reduced. On the other hand, with the COG method, the connection leads are also formed at the periphery of the LCD cell
139
in addition to a driver integrated circuit component being directly mounted, and it is therefore more difficult to reduce the width W of the frame portion than in the TAB method.
Additionally, with the increasing compactness of electronic apparatus another problem arises. For example, with the move to fine high output pin counts, one of integrated circuit components, employed in a liquid crystal display device or the like, has an elongated shape and electrodes disposed in two rows along its long dimension with wires a lead-out in two directions. Such an integrated circuit component and tape carrier are shown in FIG.
16
. In this figure, an integrated circuit component
142
, and inner leads
144
formed on a tape carrier
143
are connected by thermal bonding by a bonding tool (thermal bonding tool) not shown in the drawing. Here the tape carrier
143
has a large coefficient of thermal expansion with respect to the integrated circuit component
142
. For this reason, when the two are subjected to thermal bonding, the tape carrier
143
is thermally bonded in the extended state to the integrated circuit component
142
. However, after the thermal bonding, since the tape carrier
143
shrinks with the fall in temperature, the tape carrier
143
pulls the inner leads
144
, and the tape carrier
143
is deformed in an arc shape in the vicinity of the integrated circuit component
142
. Moreover, as the tape carrier
143
pulls the inner leads
144
, there is a possibility of breakage of the inner leads
144
.
SUMMARY OF THE INVENTION
The object of the invention is to provide a tape carrier, integrated circuit device, a method of making the same, and an electronic device, enabling miniaturization of electronic apparatus, solving the problems occurring with the miniaturization of electronic apparatus.
(1) The tape carrier of the invention for TAB comprises a base material having an insulating property and an elongated shape. The base material has peripheral edges defining an opening for disposing an integrated circuit component. A first pair of portions of the peripheral edges face each other. A second pair of portions of the peripheral edges face each other. A plurality of connection leads extend from the first pair of portions into the opening. At least one dummy lead extends from the second pair of portions into the opening.
According to the invention, after the integrated circuit component is mounted, the base material which has been heated tries to contract, but the dummy lead provided projecting in the direction of contraction supports the base material. As a result, breakage of the connection leads by shrinkage of the base material can be prevented.
Here, the term “dummy lead” refers to any part which is not used for transmitting or receiving signals or the like, and has no electrical function, and is not particularly concerned with whether or not there is a connection to an electrode of the integrated circuit component.
(2) Some dummy leads may extend from each of the second pair of portions.
(3) The dummy lead may have a width na
Oliff & Berridg,e PLC
Seiko Epson Corporation
Williams Alexander O.
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