Electricity: conductors and insulators – Conduits – cables or conductors – Insulated
Reexamination Certificate
2000-05-19
2003-10-14
Mayo, III, William H. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Insulated
C174S1170FF, C174S255000
Reexamination Certificate
active
06633002
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a tape carrier in which wiring patterns are formed on an insulating base film, and a method of manufacturing such a tape carrier. More particularly, the present invention relates to a tapes carrier with high density wiring patterns which is bent easily and which has a high reliability, and a method of manufacturing such a tape carrier. The present invention also relates to a tape carrier package (TCP) which is fabricated by attaching a semiconductor chip on such tape carrier, and a liquid crystal display device having such a TCP.
2. Description of the Related Art
A tape carrier package (TCP) used in a liquid crystal display and the like is often used in condition it is bent or folded at predetermined portion or portions thereof. Conventionally, TCP's having various structures are used to obtain good bending characteristics such as easiness of bending and the like.
For example, there is known a tape carrier structure disclosed in Japanese patent laid-open publication No. 7-28866.
FIG. 4
is a cross sectional view showing schematically the tape carrier structure disclosed in Japanese patent laid-open publication No. 7-28866. The tape carrier shown in
FIG. 4
comprises an insulating base film
31
, and a wiring pattern portion
35
bonded to the insulating base film
31
with glue
34
. On the wiring pattern portion
35
, there is formed a solder resist layer or film
37
. Also, a device hole
32
for mounting a semiconductor device is formed in the base film
31
. Further, slits
33
are formed in the base film
31
along bending portions thereof. By forming such slits
33
, it becomes possible to easily bend the tape carrier
38
along the slits
33
. Further, in order to protect the wiring pattern portion
35
exposed via the slits
33
, and to avoid disconnection or break of the wiring pattern portion
35
, a protective resin film
36
made of polyimide and the like is formed on portions of the wiring pattern portion
35
exposed via the slits
33
.
There is also known a tape carrier structure disclosed in Japanese patent laid-open publication No. 8-306741.
FIG. 5
is a cross sectional view showing schematically the tape carrier structure disclosed in Japanese patent laid-open publication No. 8-306741. The tape carrier of
FIG. 5
comprises an insulating base film
41
made of flexible and soft material, and a wiring pattern portion
44
bonded on the base film
41
with glue
43
. A surface of the wiring pattern portion
44
opposite to the base film
41
is coated with a solder resist layer
48
. Also, in the base film
41
, a device hole
42
is formed for mounting a semiconductor device. In this structure, no slit is formed in the base film
41
to facilitate bending of the base film
41
. However, a film for reinforcement
45
which is somewhat rigid and which has a slit
47
is bonded onto the base film
41
with glue
46
on the surface opposite to the wiring pattern portion
44
. Thereby, the tape carrier
49
can be easily foldable along the slit
47
.
However, in the structure described in Japanese patent laid-open publication No. 7-28866 and shown in
FIG. 4
, it is necessary to apply the protective resin film
36
of polyimide onto the portions of the wiring pattern portion
35
exposed via the slit
33
. Therefore, process steps for manufacturing such a tape carrier become complicated, and throughput of manufacturing is also deteriorated.
In the structure described in Japanese patent laid-open publication No. 8-306741 and shown in
FIG. 5
, it is necessary to use the film
45
for reinforcement in addition to the base film
41
. Thus, it needs many kinds of materials used for fabricating such tape carrier, and it results in increase of the cost.
Further, in the tape carrier structure disclosed in Japanese patent laid-open publication No. 4-342148, wiring patterns made of copper (Cu) foil which is plated with tin (Sn) are formed on an upper surface of a base film which is a plastic film made of polyimide, polyester or the like. In a bending region of the base film, slit shaped openings for bending are formed by wet etching. The slit shaped openings are parallel with the wiring patterns respectively and are formed between adjacent wiring patterns such that wiring patterns are not exposed via the slit shaped openings. Each of the slit shaped openings has a width of 60 &mgr;m (micrometers) and a length of 4 mm, and has a tapered cross section which becomes wider toward the bottom side of the base film at an angle of 30-60 degrees. The slit shaped openings are formed at a pitch of 200 &mgr;m.
In the tape carrier described in Japanese patent laid-open publication No. 4-342148, elongated slit shaped openings are formed parallel with the wiring patterns and formed between the wiring patterns throughout the bending area. Therefore, when the tape carrier is bent or a stress is applied to the tape carrier from the outside, the stress is concentrated at portions near end portions of the slit shaped openings so that there is a possibility that the base film is damaged. In order to avoid such disadvantage, it is necessary to increase the thickness of the base film to enhance the strength thereof. However, when the thickness of the base film is increased, it becomes difficult to bend the tape carrier, and it results in increase of weight and the cost of the tape carrier.
In Japanese patent laid-open publication No. 4-342148, another structure of a tape carrier is disclosed in which many and small round openings are formed by wet etching in a bending area of a base film on which wiring patterns are formed. Each of the round openings is formed between the wiring patterns such that the wiring patterns are not exposed via the round openings.
However, in this structure, since the round openings are formed between adjacent wiring patterns, when respective spaces between adjacent wiring patterns are small, it is difficult to form appropriately the round openings in the base film such that sufficient flexibility of the base film is obtained. Therefore, it is not appropriate to use this structure when spaces between wiring patterns are small. Recently, it is required that wiring patterns are formed in high density on a base film of a tape carrier, so that spaces between the wiring patterns on the base film must be very small. Thus, this structure does not suit such recent tape carrier in which wiring patterns are formed in high density.
Also, in this structure, since small round openings are formed between respective wiring patterns, it is impossible to enlarge the proportion of areas of openings in the bending area of the tape carrier sufficiently. Therefore, it is impossible to obtain good bending characteristics, such as sufficient flexibility at desired portion or portions of a tape carrier.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to obviate the above-mentioned disadvantages of the prior art.
It is another object of the present invention to provide: a tape carrier which has a simple structure, improved bending characteristics and high mechanical strength; a method of manufacturing such a tape carrier; a TCP using such a tape carrier; and a liquid crystal display device comprising such a TCP.
It is still another object of the present invention to provide: a tape carrier which can be bent easily and appropriately at a desired bending region; a method of manufacturing such a tape carrier; a TCP using such a tape carrier; and a liquid crystal display device comprising such a TCP.
It is still another object of the present invention to provide: a tape carrier which can be manufactured at low cost and which can be bent easily and appropriately at a desired bending region; a method of manufacturing such a tape carrier; a TCP using such a tape carrier; and a liquid crystal display device comprising such a TCP.
It is still another object of the present invention to provide at low cost: a tape carrier which can be bent easily and appropriately at a desi
Mayo III William H.
NEC LCD Technologies Ltd.
Scully Scott Murphy & Presser
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