Wireless IC tag and manufacturing method of the same
First Claim
1. A wireless IC tag comprising a support sheet, an antenna formed on one surface of the support sheet, an IC chip mounted on the support sheet, and a pressure sensor built in the IC chip, wherein the IC chip includes SOI structure having a silicon sheet layer, a silicon device layer, and a silicon oxide layer formed between the silicon sheet layer and the silicon device layer, and wherein the pressure sensor includes a capacitive element comprising a pair of wirings at least one of which contacts the silicon oxide layer, and a gap formed between the pair of wiring, wherein the capacitive element changes capacity of the gap by pressure applied from outside to the IC chip.
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Accused Products
Abstract
A compact wireless IC tag incorporating a pressure sensor in an IC chip. The IC chip of the wireless IC tag has SOI structure comprising a silicon sheet layer, a silicon device layer which is formed on the upper side of the silicon sheet layer, and a thin silicon oxide layer having about 0.01 μm to 5 μm thickness sandwiched between the silicon sheet layer and silicon device layer. In the silicon device layer, a capacitive element of a pressure sensor comprising of a gap, and a first metal wiring and a second metal wiring respectively disposed on the upper and lower sides of the gap, is formed. In the silicon sheet layer on the lower side of the capacitive element, an aperture filled with rubber-like elastic material is formed.
18 Citations
9 Claims
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1. A wireless IC tag comprising a support sheet, an antenna formed on one surface of the support sheet, an IC chip mounted on the support sheet, and a pressure sensor built in the IC chip,
wherein the IC chip includes SOI structure having a silicon sheet layer, a silicon device layer, and a silicon oxide layer formed between the silicon sheet layer and the silicon device layer, and wherein the pressure sensor includes a capacitive element comprising a pair of wirings at least one of which contacts the silicon oxide layer, and a gap formed between the pair of wiring, wherein the capacitive element changes capacity of the gap by pressure applied from outside to the IC chip.
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5. A wireless IC tag comprising a support sheet, an antenna formed on one surface of the support sheet, and an IC chip mounted on the support sheet,
wherein the IC chip includes SOI structure having a silicon sheet layer, a silicon device layer, and a silicon oxide layer formed between the silicon sheet layer and the silicon device layer, an pressure sensor that senses pressure applied from outside to the IC chip, and a ROM that stores an identification number specific to the wireless IC tag, wherein the pressure sensor includes a capacitive element having a pair of wirings at least one of which contacts the silicon oxide layer, and a gap formed between the pair of wirings, the capacitive element changing capacity of the gap by pressure applied from outside to the IC chip, wherein the wireless IC tag is activated by electromagnetic energy supplied from outside thereto, and transmits the identification number stored in the ROM, and the change in the capacitance value of the capacitive element, to outside.
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8. A manufacturing method of a wireless IC tag comprising a support sheet, an antenna formed on one surface of the support sheet, an IC chip mounted on the support sheet, and a pressure sensor built in the IC chip, wherein
the IC chip includes SOI structure having a silicon sheet layer, a silicon device layer, and a silicon oxide layer formed between the silicon sheet layer and the silicon device layer, and the pressure sensor includes, a capacitive element having a pair of wirings at least one of which contacts the silicon oxide layer, and a gap formed between the pair of wiring, the capacitive element changing capacity of the gap by the pressure applied from outside to the IC chip, the method comprising: -
(a) etching a part of the silicon device layer to form a groove and expose the silicon oxide layer at the bottom of the groove;
(b) subsequent to the step (a), forming a pattern on a metal film deposited on the upper side of the silicon device layer to form a pair of wirings at least one of which contacts the silicon oxide layer, and a gap between the pair of wirings; and
(c) subsequent to the step (b), etching the silicon sheet layer to form an aperture reaching the silicon sheet layer, and filling the aperture with medium comprising rubber-like elastic material. - View Dependent Claims (9)
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Specification