Wireless Ic Tag and Method for Manufacturing Same

• US 20070285254A1
• Filed: 02/24/2005
• Published: 12/13/2007
• Est. Priority Date: 02/24/2005
• Status: Active Grant

• Current Assignee: Hitachi America Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi America Limited (Hitachi, Ltd.)
• Inventors: Usami, Mitsuo
• Granted Patent: US 7,800,200 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: H01L 21/823425 manufacturing common source or drain regions between a plurality of conductor-insulator-semiconductor structures
• CPC Class Codes: H01L 21/823475 interconnection or wiring or contact manufacturing related aspects
• CPC Class Codes: H01L 23/49855 for flat-cards, e.g. credit cards cards per se G06K19/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A wireless IC tag 1 is provided with a memory circuit 304 including a ROM 307 in which an identification number is written, and a pulse width detection circuit 305 having divided resistors 111, 112, 113 and a capacitor 305 for detecting a signal waveform from a reader. In order to prevent the increase in the number of process steps and photomasks, a resistance value of the pulse width detection circuit 305 is adjusted by an electron beam writing method while utilizing a step of writing an identification number unique to the wireless IC tag 1 into the ROM (307) of the memory circuit 304.

Claims

1. A wireless IC tag comprising:

a semiconductor chip in which a memory circuit having a ROM in which a unique identification number is written and a pulse width detection circuit for detecting a plurality of clock signals having different pulse widths transmitted from a reader based on resistance and capacitance values are formed,

wherein the identification number is written into the ROM depending on the presence of a first through hole which conducts between upper and lower layer wirings connected to a transistor constituting the ROM,

the resistance value of the pulse width detection circuit is controlled by a position of a second through hole which conducts between upper and lower layer wirings connected to the resistor, and

the first through hole and the second through hole are formed in the same insulating layer on the semiconductor chip.

2. The wireless IC tag according to claim 1, further comprising:

an insulating film; and

an antenna made of a conductive film formed on one surface of the insulating film,

wherein the semiconductor chip is electrically connected to the antenna.

3. The wireless IC tag according to claim 2,

wherein the semiconductor chip is electrically connected to the antenna via bump electrodes and is sealed by resin.

4. The wireless IC tag according to claim 1,

wherein a frequency of the clock signal transmitted from the reader is 2.45 GHz.

5. The wireless IC tag according to claim 1,

wherein the resistance is made of a diffusion resistance.

6. A wireless IC tag comprising:

a semiconductor chip in which a memory circuit having a ROM in which a unique identification number is written and a pulse width detection circuit for detecting a plurality of clock signals having different pulse widths transmitted from a reader based on resistance and capacitance values are formed,

wherein the identification number is written into the ROM depending on the presence of a first through hole which conducts between upper and lower layer wirings connected to a transistor constituting the ROM,

the resistance value of the pulse width detection circuit is controlled by a position of a second through hole which conducts between upper and lower layer wirings connected to the resistor,

the capacitance value of the pulse width detection circuit is controlled by a position of a third through hole which conducts between upper and lower layer wirings connected to the capacitor, and

the first, second and third through holes are formed in the same insulating layer on the semiconductor chip.

7. A method for manufacturing a wireless IC tag, the wireless IC tag comprising:

a semiconductor chip in which a memory circuit having a ROM in which a unique identification number is written and a pulse width detection circuit for detecting a plurality of clock signals having different pulse widths transmitted from a reader based on resistance and capacitance values are formed,

wherein the identification number is written into the ROM depending on the presence of a first through hole which conducts between upper and lower layer wirings connected to a transistor constituting the ROM, and

the resistance value of the pulse width detection circuit is controlled by a position of a second through hole which conducts between upper and lower layer wirings connected to the resistor,

the method comprising the steps of;

(a) forming semiconductor devices including a transistor constituting the ROM of the memory circuit and a resistor constituting the pulse width detection circuit through a semiconductor wafer diffusion process;

(b) forming a first lower layer wiring connected to the transistor and a second lower layer wiring connected to the resistor on the transistor and the resistor;

(c) after forming an insulating film on the first and second lower layer wirings, forming a first through hole in the insulating film on the first lower layer wiring and a second through hole in the insulating film on the second lower layer wiring; and

(d) forming a first upper layer wiring connected to the first lower layer wiring via the first through hole and a second upper layer wiring connected to the second lower layer wiring via the second through hole, on the insulating film in which the first and second through holes are formed.

8. The method for manufacturing a wireless IC tag according to claim 7,

wherein the first and second through holes are formed by an electron beam writing method.

9. The method for manufacturing a wireless IC tag according to claim 7, further comprising the steps of:

before the step (c), measuring the resistance value; and

determining a position pattern of the second through hole based on the resistance value.

10. The method for manufacturing a wireless IC tag according to claim 7, further comprising the steps of:

after the step (d), (e) dicing the semiconductor wafer and dividing into a plurality of semiconductor chips; and

(f) connecting the respective semiconductor chips to an antenna made of a conductive film which is formed on one surface of an insulating film.

11. The method for manufacturing a wireless IC tag according to claim 7,

wherein a frequency of the clock signal transmitted from the reader is 2.45 GHz.

12. The method for manufacturing a wireless IC tag according to claim 7,

wherein the resistance is made of a diffusion resistance.