Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2000-01-27
2003-04-29
Paladini, Albert W. (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S261000, C174S255000, C029S846000
Reexamination Certificate
active
06555755
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flexible interconnecting substrate and a method of fabrication thereof, a film carrier, a tape-shaped semiconductor device, a semiconductor device, a circuit board, together with electronic equipment.
2. Description of the Related Art
Tape automated bonding (TAB) is known in the art for mounting semiconductor chips onto a flexible interconnecting substrate. This flexible interconnecting substrate often comprises a flexible base substrate of a polyimide and an interconnecting pattern formed by machining a foil copper material on top thereof. Warping is likely to occur in a prior-art flexible interconnecting substrate, due to heating that is applied during heating steps partway through the fabrication. If the base substrate becomes bent, a problem will occur in that the reliability of connections with semiconductor chips or mounting substrates will deteriorate.
SUMMARY OF THE INVENTION
The present invention was devised to solve these problems and has as an objective thereof the provision of a flexible interconnecting substrate and a method of manufacturing the same, a film carrier, a tape-shaped semiconductor device, a semiconductor device, a circuit board, and electronic equipment that make it possible to reduce warping of a base substrate.
(1) A flexible interconnecting substrate in accordance with the present invention comprises a tape-shaped base substrate and a plurality of interconnecting patterns formed on the base substrate, wherein:
each of the interconnecting patterns has a plurality of interconnects, and
each of interconnects has a portion extending in a direction of a first side edge of a widthwise direction of the base substrate, and a portion extending in a direction of a second side edge of the widthwise direction of the base substrate, the directions of the first and second side-edges crossing with a longitudinal axis of the base substrate.
Note that in this aspect of the invention, “interconnect” indicates a portion in contact with at least two electrical contact points and “interconnecting pattern” indicates all of a plurality of interconnects comprised within one final product (such as a semiconductor device). A flexible interconnecting substrate in accordance with the present invention comprises a plurality of interconnecting patterns for manufacturing a plurality of final products.
With this aspect of the invention, interconnects have portions that extend in the directions of first and second side edges, so that the interconnects provide support in a plurality of directions even if the base substrate expands or contracts, thus making it possible to reduce warping of the base substrate.
(2) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have a plurality of interconnect portions aligned along an extending direction of the interconnecting patterns, the interconnecting portions comprising regions of plurality types of width being disposed on the base substrate.
This ensures a configuration in which the interconnecting pattern goes obliquely with respect to the direction of extension of the interconnecting pattern, within the region between the interconnecting portions having different width of disposed region. The strength of the material that forms the interconnecting pattern can therefore be increased in directions other than the direction of extension of the interconnecting pattern, and also the bending strength of the base substrate can also be increased. As a result, it is possible to prevent the generation of warping in the base substrate because the interconnecting pattern provides support even when a force that causes warping is applied to the base substrate. Since the interconnecting pattern goes obliquely with respect to the extending direction of the interconnecting pattern, even when the material of the interconnecting pattern and the material of the base substrate have different coefficients of thermal expansion, stress is applied in a direction that the base substrate is difficult to be warped. It is therefore possible to reduce the amount of warping generated in the base substrate.
(3) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have a plurality of interconnect portions aligned along a longitudinal direction of the base substrate, the interconnecting portions comprising regions of plurality types of width being disposed on the base substrate.
This ensures a configuration in which the interconnecting pattern goes obliquely with respect to the longitudinal direction of the base substrate, within the region between the interconnecting portions having different width of disposed region.
The strength of the material that forms the interconnecting pattern can therefore be increased in directions other than the longitudinal direction of the base substrate, and also the bending strength of the base substrate itself can also be increased. As a result, it is possible to prevent the generation of warping in the base substrate because the interconnecting pattern provides support even when a force that causes warping is applied to the base substrate. Since the interconnecting pattern goes obliquely with respect to the longitudinal direction of the base substrate, even when the material of the interconnecting pattern and the material of the base substrate have different coefficients of thermal expansion, stress is applied in a direction that the base substrate is difficult to be warped. It is therefore possible to reduce the amount of warping generated in the base substrate.
(4) With the above described flexible interconnecting substrate,
one of the interconnect portions may be a wide portion that expands the width of a region disposed on the base substrate between the first and second side edges, and
another of the interconnect portions may be a narrow portion that narrows the width of the region disposed on the base substrate between the first and second side edges.
(5) With the above described flexible interconnecting substrate,
the wide portion may be a maximum of the width of the region disposed on the base substrate, and
the narrow portion may make the width of the region disposed on the base substrate narrower than the width of the wide portion.
(6) With the above described flexible interconnecting substrate,
the narrow portion may have a plurality of direction-changing portions for changing the direction of each of the interconnecting patterns.
(7) With the above described flexible interconnecting substrate,
the width of a portion of each of the interconnects positioned at the wide portion may be wider than the width of a portion thereof positioned at the narrow portion.
This makes it possible to vary the pitch of interconnects, utilizing a configuration for preventing warping of the base substrate.
(8) With the above described flexible interconnecting substrate,
a pitch of the interconnects adjoining each other at the wide portions may be wider than the pitch thereof at the narrow portions.
This makes it possible to vary the pitch of interconnects, utilizing a configuration for preventing warping of the base substrate.
(9) With the above described flexible interconnecting substrate,
a slit may be formed in the base substrate so as to extend in the widthwise direction thereof.
This configuration ensures that the formation of a slit makes it easy to bend the base substrate.
(10) With the above described flexible interconnecting substrate,
the slit may be formed in a region where the wide portion is formed.
This configuration ensures that the slit is formed in a region where a wider portion of the interconnect is formed, in other words, where a portion of the interconnect that is stronger is formed. Therefore, forming the slit ensures that breakages are prevented by the increased strength of the interconnect itself, even if the strength of the base substrate or the strength that supports the interconnect should decrease.
(11) With the above described flexi
Norris Jeremy
Paladini Albert W.
Seiko Epson Corporation
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