CN101604406A - A kind of manufacture method of passive RFID - Google Patents

Abstract

In order to be reduced in existing active RFID higher cost in the logistics field prior art, the invention provides a kind of manufacture method of passive RFID, this method may further comprise the steps: (1) cutting silicon is as the substrate of passive RFID; (2) in described substrate, attach and etched line around inductive antenna; (3) use the electrically conductive ink printing process in described substrate, to print printed circuit board (PCB); (4) described RFID is encapsulated.

Description

A kind of manufacture method of passive RFID

Technical field

[001] this paper relates to the manufacture method of a kind of RFID (radio-frequency (RF) identification), more specifically, relates to a kind of manufacture method of passive RFID.

Background technology

[002] the English full name of RFID is Radio Frequency Identification, the RFID radio-frequency (RF) identification says to be exactly a kind of contactless automatic identification technology simply, it is by the automatic recognition objective object of radiofrequency signal and obtains related data, whole identification work need not manual intervention, can work in various rugged surroundings.It mainly partly is made up of the electronic tag that has chip (chip), read write line (writer-reader), communication system etc.The groundwork principle is: after electronic tag enters the magnetic field of read write line launching electromagnetic wave, accept radio frequency signal, rely on the energy that induction current obtained to send out the data message that is stored in the chip, after read write line reads information and decoding, deliver to CIS and carry out the related data processing.

[003] country relies on the huge advantage of technical elements Europe, the United States, day etc., and they are in leadership in RFID Study on Technology and application facet.No matter be in the manufacturing and designing of professional equipment, still silicon wafer, the label antenna at the RFID label manufacture and design, encapsulation, read write line the aspect such as design and develop, all lead over other countries and area.Under giants' such as Wal-Mart, METRO, Pfizer, U.S. Department of Defense promotion, worldwide the development of RFID The Application of Technology is very swift and violent.

[004] along with the reduction of reader and sticker price and the expansion of world market, the application of radio frequency identification RFID (hereinafter to be referred as RFID) grows with each passing day.Label both can be powered by reader (passive label), also can be by power supply power supply (semi-active label and active label) on the plate of label.Because the cost of the passive CMOS label of submicron reduces, stock and other application increase sharply.Some assessments show, along with the price of passive label continues to descend, almost all will there be a RFID label each inside of selling product.Because the challenge of the Project Realization of the importance of passive RFID tags and uniqueness thereof, this paper is with the primary study passive tag systems.

[005] when the CW signal that receives from reader, passive label carries out rectification to radio frequency (hereinafter to be referred as RF) energy and keeps the required fraction energy of label work to generate, the absorption characteristics that changes its antenna then is with modulation signal, and reflects to reader by backscattering.Modulation technique that rfid system is easy to use usually and coding system.Yet the spectrum efficiency of simple modulation technology is low, and for a certain given data rate, its desired RF bandwidth is many.Before modulation, data must be encoded forms a continuous information flow.Available position coding body is shaped on a lot of types, and each class coding all has the unique advantage of its baseband frequency spectrum performance, the complicacy of encoding and decoding and the difficulty that writes data into storer under clock drives.Because timing source is difficult to the accuracy that reaches actual required on the tag board, and challenging bandwidth requirement and maximization RF power transfer be with to reasons such as label supplying energies, and passive label is shaped on unique requirement to employed coding body.At last, need certain anticollision protocol so that reader can read all labels in its coverage.

[006] passive RFID has occurred for some time on low frequency (125kHz) and high frequency (13.56MHz) market.Before 2003, multiple UHFRFID standard has appearred.The problem of multiple patent RFID standard has been recognized at Massachusetts Institute of Technology (MIT) automobile sign center (Massachusetts Instituteof Technology ' sAuto-ID Center) (being positioned at Cambridge, Massachusetts), recognizes that endemic consultation stops the development of RFID technology and popularizes.For building mutual usefulness and the international regulations of deferring to, just need single, open standard.They recommend UHFRFID of future generation---there are two meanings in the predecessor who is the Gen2 standard.In case single international standard places is got off, based on the system applies of UHFRFID will be faster, use is more convenient, price is more cheap, the multi-provider channel can occur.This automobile sign center proposes to start the work of Gen2 in June, 2003 in discussion of Zurich, SUI.They develop the most at last and the work of this standard of commercialization changes into EPCglobal, and be " 860MHz is to 960MHz second generation UHFRFID communications protocol " with this standard approval in Dec, 2004.

[007] from the RFIDIC design angle, there are two main design constraints in RFID: the complicacy of power availability/bandwidth and transponder.Passive UHFRFID transponder design requires the compromise factors such as power requirement, complicacy and chip size of considering, to obtain the performance of expectation.

[008] present, some major countries to spectrum allocation may, bandwidth and the radiation power of UHF industry, science and medical science (ISM) frequency range require widely different.Radiation power often is defined as effective isotropically radiated power (EIRP).According to " the EPC whole world " standard, the uhf band scope is from 860MHz to 960MHz, and the power level of permission is 4W.But different regions are to the requirement difference of UHFISM frequency range: in the North America, the UHFISM frequency range be 902MHz to 928MHz, maximum EIRP is 4W; In Europe, the UHFISM frequency range be 865MHz to 868MHz, maximum EIRP is 2W; In Japan, the UHFISM frequency range be 952MHz to 954MHz, maximum EIRP is 4W.

[009] passive RFID tags itself charged pool not, the electromagnetic energy work that relies on card reader to send.Because it is simple in structure, economical and practical, thereby obtain to use widely.Passive RFID tags is made up of RFID IC, resonant capacitance C and antenna L, and antenna and electric capacity are formed resonant tank, is tuned at the carrier frequency of card reader, to obtain optimum performance.

[010] production firm follows the standard of International Telecommunications Union (ITU) mostly, and the frequency that RFID uses has 6 kinds, is respectively 135KHz, 13.56MHz, 43.3-92MHz, 860-930MHz (being UHF), 2.45GHz and 5.8GHz.Passive RFID mainly uses the first two to plant frequency.

[011] though the China Logistics industry is in Rapid development stage, the strict demand of cost helps the rapid expansion of logistics company business.Existing RFID majority all is active RFID on the market, though this RFID has advantage at aspects such as the scope of applications, but for being in nascent numerous logistics company, its cost is higher, is unfavorable for this advanced person's of RFID logistlcs technology is used and is generalized in the modern logistics practice.

Summary of the invention

[012] in order to be reduced in existing active RFID higher cost in the logistics field prior art, the invention provides a kind of manufacture method of passive RFID, this method may further comprise the steps:

[013] (1) cutting silicon is as the substrate of passive RFID;

[014] (2) in described substrate, attach and etched line around inductive antenna;

[015] (3) use the electrically conductive ink printing process to print printed circuit board (PCB) in described substrate;

[016] (4) encapsulate described RFID.

[017] the electrically conductive ink printing in the described manufacture process can also substitute with offset printing, flexographic printing.

[018] attaching of described antenna be to use directly amplexiform, in wire bonds or the reverse installation process any one.

[019] form of described encapsulation use is the FPGA packing forms.

Description of drawings

[020] Fig. 1: the structural map of passive RFID of the present invention.

[021] Fig. 2: the method for attachment of MCRF355 among the present invention.

[022] Fig. 3: the method for attachment of MCRF360 among the present invention.

[023] Fig. 4: the manufacture method FB(flow block) of passive RFID.

Embodiment

[024] among the present invention, details are as follows for the structure of passive RFID:

[025] 1. label (Tag, i.e. radio-frequency card): be made up of coupling element and chip, label contains built-in aerial, is used for communicating with radio-frequency antenna.Each label has unique electronic code, attached to identifying destination object on the object.

[026] 2. reader (Reader): read the equipment of (can also write sometimes) label information, can be designed to hand-held or fixed.

[027] 3. antenna (Antemm): ask the transmission radiofrequency signal at label and reader.

[028] this passive RFID uses impression or printing rotten spiral antenna at quarter on medium silicon plate, have the bare chip COB that directly amplexiforms on antenna, and this bare chip amplexiforms directly on described antenna.

[029] reader of described passive RFID can be designed to hand-held or fixed.

[030] described COB adopts the IOA2 encapsulation.

[031] memory data of described passive RFID can entrust factory to programme before dispatching from the factory, also can be at the scene with the programming of contact programmable device.

[032] the groundwork flow process of rfid system is: reader produces induction current by the radiofrequency signal of emitting antenna transmission certain frequency when radio-frequency card enters the perform region of emitting antenna, radio-frequency card obtains energy and is activated; Radio-frequency card sends information such as self coding by the built-in aerial in blocking: the carrier signal of sending from radio-frequency card that system's receiving antenna receives, be sent to reader through the antenna adjustments device, reader carries out the demodulation sign indicating number to the signal that receives, and delivers to the backstage main system then and carries out relevant treatment; Main system is judged the legitimacy of this card according to logical operation, makes corresponding processing and control at different set, sends the action of command signal control executing mechanism.Some system also is connected with outer computer (host computer main system) by the RS232 or the RSR4855 interface of reader, carries out exchanges data.

[033] the RFID label antenna has two kinds of antenna forms: (1) wire-wound inductive antenna; (2) rotten spiral antenna is carved in impression or printing on medium substrate.Antenna form is determined by factors such as carrier frequency, tag package form, performance and assembly costs.Need mH level inductance value, this class antenna can only use the wire-wound inductance to make when for example, frequency is less than 400KHz; Frequency only needs several when 4～30MHz , several astragals are just passable around inductance, or corruption at the quarter on working medium substrate antenna.

[034] behind the selection antenna, next step is exactly how silicon IC to be amplexiformed on antenna.IC amplexiforms also two kinds of basic skills: (1) uses chip on board (COB); (2) bare chip directly amplexiforms on antenna.The former is usually used in the wire-wound antenna; And the latter is used to carve rotten antenna.CIB is encapsulated in resonant capacitance and RFID IC in the same shell together, antenna then with flatiron or welding process be connected COB 2 external connection end on.Because most of COB are used for the ISO card, the card of a kind of according to the ISO standard thickness (0.76) specification, so the typical thickness of COB is about 0.4mm.Two kinds of common COB packing forms are the IOA2 (MOA2) that adopts of IST and the World II of U.S. HEI Inc. employing.

[035] bare chip directly amplexiforms and has reduced intermediate steps, is widely used for low cost and high volume applications.Directly amplexiforming also has two kinds of methods available, (1) wire bonds; (2) reverse installation process.When adopting reverse installation process, need on the chip bonding pad to make special soldered ball, material is golden, highly about 25 Xie, then with solder-ball flip on the printing cabling of antenna.Wire bonds technology is simpler, and bare chip directly uses wire bonds on antenna, and the weld zone seals with black epoxy again.To small serial production, the cost of this technology is lower; And, preferably adopted reverse installation process for production in enormous quantities.

[036] the manufacture method following steps of the passive RFID described in the present invention:

[037] (1) cutting silicon is as the substrate of passive RFID;

[038] (2) in described substrate, attach and etched line around inductive antenna;

[039] (3) use the electrically conductive ink printing process to print printed circuit board (PCB) in described substrate;

[040] (4) encapsulate described RFID.

[041] the electrically conductive ink printing in the described manufacture process can also substitute with offset printing, flexographic printing.

[042] attaching of described antenna be to use directly amplexiform, in wire bonds or the reverse installation process any one.

[043] form of described encapsulation use is the FPGA packing forms.

[044] MCRF 355/360 is the 13.56MHz device that Microchip company produces.355 both can be used for COB, also can be used for directly amplexiforming; And there is 1 100pf electric capacity 360 inside, only need external inductors.This device is close to 100% modulation and sends data, and depth of modulation has determined the variation of coil voltage from " height " to " low " of label, that is distinguishes tuning state and de-tuned state.

[045] the outward element value is optimized at 1/3rd to 1/2nd places usually.For example, telefault is 3 circles between antenna A and antenna B, and that is not 1 circle between the antenna B to VSS.When MCRF 355 is made into COB, the 68Pf same capacitance of built-in 2 series connection.Capacitor C 1 is connected antenna A between the antenna B, and C2 is between antenna B to Vss.

[046] in order to reach the performance of design, label should be tuned at the carrier frequency of card reader exactly.Yet the element that uses is always devious, causes the variation of reading distance.The error of inductance can be controlled in 1～2%, so reading distance is mainly caused by capacitance error.The error of external capacitor should be in 5%, and the Q value is greater than 100.The internal capacitance of MCRF360R is made of monox, and the error on the same silicon chip is in 5%, and the error of different batches is about 10%.

[047] memory data of MCRF355/360 can entrust factory to programme before dispatching from the factory, also can be at the scene with the programming of contact programmable device.

[048] Fig. 2-3 shows the method for attachment of device.Fig. 2 designs for MCRF355, external 2 inductance and 1 electric capacity, and corresponding resonance frequency is:

[049] f (tuning)=1/2p

[050] f (de-tuned)=1/2p

[051]LT＝L1+L2+Lm

[052] in the following formula, Lm is coefficient of mutual inductance K; K is coupling coefficient between two inductance (0≤K≤1).

[053] Fig. 3 is the MCRF360 method of attachment, because there is an electric capacity its inside, so only need external 2 inductance just passable, the frequency computation part formula is identical with MCRF355.

Claims (4)

1. the manufacture method of a passive RFID, this method may further comprise the steps:

(1) the cutting silicon is as the substrate of passive RFID;

(2) in described substrate, attach and etched line around inductive antenna;

(3) use the electrically conductive ink printing process in described substrate, to print printed circuit board (PCB);

(4) described RFID is encapsulated.

2. according to the manufacture method of a kind of passive RFID of claim 1, the electrically conductive ink printing in the described manufacture process can also substitute with offset printing, flexographic printing.

3. according to the manufacture method of a kind of passive RFID of claim 1, the attaching of described antenna is to use directly and amplexiforms, in wire bonds or the reverse installation process any one.

4. according to the manufacture method of a kind of passive RFID of claim 1, the form that described encapsulation is used is the FPGA packing forms.

Images