Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-01-26
2004-03-02
Talbott, David L. (Department: 2827)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S793000, C361S795000, C257S700000, C257S724000
Reexamination Certificate
active
06700796
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a transponder provided with an integrated circuit, an antenna, and a first capacitor provided with a dielectric and a first and a second capacitor electrode, which transponder comprises a stack of layers, i.e.:
a first layer of a dielectric material,
a first patterned electrically conductive layer of which the antenna forms part,
a second layer of a dielectric material, and
a second patterned electrically conductive layer.
The invention further relates to an appliance provided with a transponder which comprises an integrated circuit, an antenna, and a first capacitor.
BACKGROUND OF THE INVENTION
Such a transponder is known from EP-A-840251. The second layer of dielectric material in the known transponder is the dielectric of the capacitor and at the same time the substrate. The transponder comprises an electrically conductive connection which is passed through the second layer of dielectric material. This connection is present in the form of a metal-filled hole in the second layer. The integrated circuit—also referred to hereinafter as IC—of the known transponder is separately manufactured and is provided on the second patterned layer in an assembling step. To protect the second patterned layer and the IC, the known transponder comprises a top layer of dielectric material. The antenna of the known transponder is present in the first patterned layer which is manufactured separately from the second patterned layer on the first layer of dielectric material. The two halves of the transponder are subsequently assembled together.
A disadvantage of the known transponder is that its cost price is high, as an assembling step of the IC is necessary.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a transponder of the kind described in the opening paragraph which can be manufactured at a low cost price. A second object of the invention is to provide an appliance of the kind mentioned in the second paragraph which comprises a transponder which can be integrated in the appliance in a simple manner.
The first object is achieved in that the second patterned layer comprises a first electrode of the integrated circuit and the second capacitor electrode.
The second patterned layer does not only comprise the second capacitor electrode, as in the cited application, but also the first electrode of the IC. Instead of assembling an IC, the IC is processed onto the second layer or a further layer of dielectric material. An additional advantage of said processed IC is that bonding problems are absent. Such problems include a bad electrical connection, a bad adhesion to the second layer of dielectric material. Further on, the flexibility of the IC is enhanced in that a processed IC can be flexible whereas an assembled IC is not. Another advantage is that in the design the condition of ease of assemblage of the IC is absent. This condition being absent, the design can be optimized to have large capacitor electrodes and large contact surfaces, if present. In the case that in the manufacture of the transponder two halves are processed independently and assembled during a later step, the large size of electrodes and contact surfaces facilitates an easy assembly of both halves.
The processed IC further comprises other parts such as a semiconductor and a second electrode. These parts may be present in the form of doped regions in a layer of a semiconducting material such as silicon. The IC may alternatively comprise a layered structure. The first electrode of the IC may form part of a first transistor or of a first diode. Preferably, the IC comprises several transistors as well as interconnect lines between the transistors. Said interconnect lines can be present in the second patterned electrically conductive layer. Preferably, the IC further comprises one or several memory elements.
It is advantageous that the second layer of dielectric material is the dielectric of the first capacitor and comprises a first interconnection between the antenna and the integrated circuit. In this case, the second layer of dielectric material is not only the dielectric of the first capacitor, but it also has the functions of an insulator between and of a protective layer for the first and the second patterned layer. Preferably, the dielectric material of the second layer has a relative dielectric constant ∈
&tgr;
of approximately 3 to 30. A semiconducting layer may be in contact with the layer of dielectric material. Preferably, the semiconducting layer is thinner than the second layer of dielectric material.
By preference, the first patterned layer comprises not only the antenna, but also the first capacitor electrode. This layer may in addition comprise a first contact surface which is in contact with or forms part of a first connection. Preferably, the integrated circuit is connected to the antenna by means of this first interconnection.
There are various embodiments of the transponder according to the invention which differ from one another in the nature of the interconnection between the antenna and the IC. The number of connections is at least two, because the antenna and IC form part of a closed electric circuit. In a first embodiment, there is a connection between the first and the second patterned layer through the second layer of dielectric material, which second layer is patterned. There are various methods for the manufacture of a hole in the second layer which is then to be filled—a connection which is known to those skilled in the art as a vertical interconnect area or via—, for example, a mechanical and a photochemical method.
In a second embodiment, there is an interconnection between the first and the second patterned layer which extends outside the layer of dielectric material. This embodiment has the advantage that no through hole need be filled, which would be an additional step in the manufacture. In a third embodiment, there is a connection at the outside of the transponder. Such a connection comprises roughly a U-shaped part.
In a fourth, favorable embodiment of the transponder, the first capacitor constitutes the interconnection. A first advantage of the use of capacitors as interconnect members is that this saves a patterning of the second layer of dielectric material. A second advantage is that no problems can arise as regards positioning of the second patterned layer with respect to the first.
The antenna in the transponder according to the invention serves for communication with a base station. At least three techniques are known by which such a communication can take place. The first technique is inductive coupling, where the communication takes place magnetically. When this technique is used, a coil is present in the pattern of the first layer on the transponder, and a capacitor is present in a tuned circuit. The second technique is capacitive coupling, where the communication takes place electrically. In this case, two capacitor plates are present on the transponder, which plates communicate with one or several capacitor plates in the base station. A diode is further present in the tuned circuit. The third technique makes use of radiation, i.e. communication takes place by electromagnetic means.
The integrated circuit in the transponder according to the invention is present in an electric circuit which is usually operated with direct current. Since the tuned circuit is usually operated with alternating current, a diode and a capacitor will mostly be present in the current path of the integrated circuit. Preferably, the diode is integrated into the IC. The diode may be present in the form of a field effect transistor provided with a gate, a source, and a drain electrode, the gate electrode being short-circuited with the source or drain electrode. The capacitor referred to above has a smoothing function. Said capacitor may be integrated into the IC, the dielectric between the gate electrode and the semiconducting layer being at the same time the dielectric of this capacitor. Said capacitor may alternatively be integrat
Bordes Bente Adriaan
De Leeuw Dagobert Michel
Detcheverry Celine Juliette
Hart Cornelis Maria
Lifka Herbert
Koninklijke Philips Electronics , N.V.
Piotroski Daniel J.
Talbott David L.
Vigushin John B.
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