Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Assembly of plural semiconductive substrates each possessing...
Reexamination Certificate
2000-06-12
2002-08-27
Talbott, David L. (Department: 2827)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Assembly of plural semiconductive substrates each possessing...
Reexamination Certificate
active
06440773
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a thin semiconductor device, and especially a highly reliable IC card which has flexibility.
BACKGROUND ART
Conventional thin semiconductor devices, e.g., IC cards, are disclosed on pages 603 to 605 of “Electronics, Information and Communication Handbook” (second issue of the first edition, published on Apr. 30, 1990), edited by a corporation of the institute of electronics, information and communication engineers, printed by OHM Corporation and disclosed in Japanese Patent Publication No. Hei 7-99267.
FIG. 31
shows a sectional structure of a conventional contact-type IC card chip module. Bonding pads
3131
formed on a module substrate
3136
are connected to external terminals of a semiconductor chip
3134
through bonding wires
3132
. These components are molded with a molding resin
3133
. The bonding pads
3131
are connected through via holes
3137
formed in the module substrate
3136
, which is a hard substrate, to contact electrodes
3135
, which are for output and input of signals to and from the exterior and for the supply of electric power to an IC card.
FIG. 34
shows a process for manufacturing an IC card which includes the IC card chip module shown in FIG.
31
. The manufacturing process comprises an upper-side photoresist films forming step for patterning the bonding pads
3131
, etc. on an upper side of the module substrate
3136
, a lower-side photoresist films forming step for patterning the contact electrodes
3135
, etc., a conductive film etching step using a photoresist film as a mask, a step of forming via holes
3137
in the module substrate (a glass epoxy substrate)
3136
, a step of plating the interior of each via hole
3137
, a step of cutting a plurality of semiconductor chips
3134
(pellets), formed separately on a semiconductor wafer, a step of bonding each of the thus-cut semiconductor chips
3134
onto the module substrate
3136
, a step of bonding the electrode on the semiconductor chip and the bonding pads
3131
with each other through wires
3132
, a step of molding the semiconductor chip and bonding pads with resin to afford a molded chip (completion of an IC chip module), a step of milling a card substrate for mounting the molded chip thereon to form a recess, a step of applying an adhesive to the milled recess, and a step of bonding the molded chip into the recess.
FIG. 6
is a sectional view of a conventional non-contact type IC card. As shown in the same figure, a semiconductor chip
62
and the ceramic capacitors
61
and
64
are mounted on a hard substrate
66
. These are connected together through bonding wires and are molded with an epoxy resin
63
. The ceramic capacitor
64
is connected to a winding coil
67
, which is for output and input of signals and for the reception of energy. These components are mounted between two overcoating substrates
65
, which are softer than the substrate
66
.
FIG. 41
is a sectional view of an IC card in which a thin capacitor chip
4151
and a thin IC chip
4153
are mounted on a neutral surface. External terminals of the thin capacitor chip
4151
and the thin IC chip
4153
are connected, using an electrically conductive adhesive, to electrodes
4155
,
4157
, and
4158
, which are screen-printed on a flexible substrate
4156
. Further, spacers
4154
and
4159
are disposed in regions where the thin capacitor chip and the thin IC chip are not present, and an upper cover
4152
is provided opposedly to the substrate
4156
so as to cover those components.
In fabricating IC cards with the structures shown in
FIGS. 6 and 31
, certain problems arise. For example, the manufacturing process becomes long and the manufacturing cost increases, as explained above with reference to FIG.
34
. A further problem is involved therein such that the IC chip is as thick as several hundred microns and cracks upon the imposition of a bending stress thereon. A structure is known in which a reinforcing member is provided for the prevention of cracking against a bending stress. However, since this structure is for the prevention of bending, the reinforcing member used is thick and the IC card itself cannot be made thinner than 0.76 mm or so.
The IC card of the structure shown in
FIG. 41
is advantageous in that the manufacturing cost is low, and that the card is highly resistive to a bending stress because a thin IC chip is disposed on the neutral surface. However, it was found out for the first time by the inventor in the present case that the thin capacitor chip and the thin IC chip were easily broken under the action of a local compressive force (point pressure) with a ball-point pen or a pencil, and that the use of the IC card is limited.
It is an object of the present invention to provide a semiconductor chip-mounted card having a structure which permits a reduction in the manufacturing cost of semiconductor devices having various thicknesses.
It is another object of the present invention to provide a semiconductor device using the above semiconductor chip-mounted card.
It is a further object of the present invention to provide a highly reliable, card-like semiconductor device having an IC chip which is difficult to break even under a local pressure (point pressure), particularly a local pressure applied to a region not larger than 1 mm
2
.
It is another object of the present invention to provide a highly reliable, non-contact type IC card.
It is a still further object of the present invention to provide a highly reliable multi-function IC card which is easy to use.
DISCLOSURE OF THE INVENTION
The above objects are achieved by a card-like semiconductor device having a thin, flexible IC chip which is 0.1 to 110 microns in thickness, wherein a reinforcing plate harder than a card substrate is provided on at least one side of the IC chip for reinforcement against a local stress. Since a local stress to be imposed on the IC chip is dispersed by the reinforcing plate, the IC chip becomes difficult to break.
For the reinforcing plate a metallic or resinous plate may be used. The use of a metallic plate permits the formation of a thinner film than in the use of a resinous plate. A suitable thickness of the reinforcing plate is in the range of 1 to 110 microns. With such a degree of thickness, the reinforcing plate can be bent following a bending stress. The reinforcing plate may be provided on both sides of the IC chip.
A semiconductor device of a higher reliability can be obtained by using a shade film which intercepts light (electromagnetic wave) traveling to the IC chip.
For the shade film, a conductive paste may be used. The shade film can be formed simultaneously with the formation of the electrode or coil by printing onto a card substrate using a conductive paste. By selecting a suitable material, the reinforcing plate can be used as a shade film.
By using a master IC chip and a plurality of slave IC chips, a semiconductor device of a higher reliability can be obtained. The master and slave IC chips are connected with each other. The master IC chip has the function of exchanging data with the exterior, while the plural slave IC chips have the function of storing data of the same contents and issuing an “abnormal” signal upon the destruction of any chip. Even in the event of the destruction of any of the slave IC chips, it is possible to read out the stored data.
Printed coil may be formed on one side or both sides of the card substrate. It may be formed on only one side in the case of being used in close proximity to the IC card reader. By forming coils on both sides of the card substrate, it becomes possible to detect a weaker radio wave.
The use of an IC chip having a plastic resin-coated surface permits a further improvement of reliability. As a result, a stress onto the IC chip surface induced by conductive particles can be relaxed when external terminals of the IC chip are connected to substrate electrodes through an anisotropic conductive adhesive or film.
By using an IC chip with projection-like bumps formed at the portions of the connecting termi
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Talbott David L.
Zarneke David
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