CN101909408B - Method for implanting RFID (radio frequency identification) signal into PCB (printed circuit board) - Google Patents

Abstract

A method for implanting a radio frequency identification RFID tag in a printed circuit board relates to the field of printed circuit board manufacturing and the application field of ultra-high frequency RFID, and discloses a method for implanting an ultra-high frequency RFID in a printed circuit board to achieve anti-counterfeiting and tracer purposes. Different from directly embedding or surface-mounting the packaged RFID tags, the basic feature of the present invention is that the unpackaged RFID chip is directly embedded in the printed circuit board, and the antenna is manufactured in the printed circuit board, and the layer-up is used. This technology completes the interconnection between the antenna and the chip within the printed circuit board. The invention saves the primary packaging of the RFID chip and the antenna, and the embedding of the chip and the manufacture of the antenna are compatible with the processing technology of the printed circuit board, and the RFID tags can be produced in batches on the entire board at the same time, thereby reducing the application cost of embedding the RFID tags .

Description

A method of implanting radio frequency identification (RFID) signals in printed circuit boards

technical field

The present invention relates to the field of printed circuit board manufacturing and the field of UHF RFID application, mainly a structure of embedding UHF RFID in the printed circuit board, embedding and manufacturing the RFID chip and the antenna in the printed circuit board respectively, And complete the interconnection, so that the anti-counterfeiting and tracing functions can be completed.

Background technique

According to the idea of modern electronic assembly, printed circuit boards are divided into different types at different stages of the electronic assembly process. Different types of printed circuit boards (Printed Circuit Board, PCB) have slightly different functions and different application directions. Packaging substrates are used in the first level of electronic assembly. A single chip is directly mounted on this substrate to form a packaged substrate; conventional printed circuit boards are used in second and third-level electronic assembly, as the mother board that constitutes the system, and are used to assemble discrete devices and packaged integrated chips.

The structure of a printed circuit board is generally composed of a single-layer or multi-layer copper conductive pattern layer. The dielectric layer is used to support and insulate the conductive pattern layers. The interconnection between the layers is realized by the layer-up method. Affixed to the surface of the printed circuit board board.

Figure 1 is an example of a 4-layer PCB board. The 4-layer PCB board is made of 7 layers of material. 101 and 107 are signal layers, 103 is a power plane, 105 is a ground layer, between 103 and 105 is insulated and supported by 104, that is, a core board, between 101 and 103, and between 105 and 107, by a dielectric material (102, 106) Insulation.

RFID, or Radio Frequency Identification, is an automatic identification technology that emerged in the 1990s. Radio frequency identification technology uses radio frequency signals to realize non-contact information transmission through spatial coupling (alternating magnetic field or electromagnetic field) and achieve the purpose of identification through the transmitted information. Among them, UHF RFID is ultra-high frequency radio frequency identification technology. The working frequency is between 860MHz and 960MHz. The radio waves in this frequency band cannot pass through many materials, especially water, dust, fog and other suspended particulate matter. Compared with high-frequency RFID (working frequency 13.56MHz), UHF electronic tags do not need to be separated from metal. Another advantage of UHF RFID is the high data transmission rate, which can read a large number of electronic tags in a short time.

In the printed circuit board industry, there is a need for a suitable way to carry out anti-counterfeiting marks and confirm the whereabouts of the printed circuit board products produced. The initial method is to manually attach barcodes on the surface, and then to attach RFID tags that can automatically read data on the surface. As shown in FIG. 2 , on a mounted printed circuit board 201 , select a suitable space to mount a barcode or RFID label 202 . However, manual mounting is a waste of time, and the form of surface mounting cannot protect the label well, so as to ensure the anti-counterfeiting and traceability functions. Because the label attached to the surface may be damaged artificially or accidentally, such as peeling, scratching and so on. Therefore, people began to consider embedding RFID tags inside the substrate, because RFID tags have a certain reading distance, and embedding inside the substrate will not affect its data reading, and effectively protect the RFID tags. As shown in FIG. 3 , it is an existing structure of embedding RFID tags inside a printed circuit board. Taking a double-layer board as an example, an RFID tag 303 is embedded in the dielectric layer 302 between the signal layers 301 and 304 .

The invention proposes a new embedding method for embedding UHF RFID in a printed circuit board.

Contents of the invention

The purpose of the present invention is to provide a method for embedding UHF RFID tags in printed circuit boards, omitting the packaging of RFID tags, directly embedding unpackaged UHF RFID chips, and using the printed circuit board manufacturing process to complete the antenna The production and interconnection between chips and antennas, thereby reducing costs, and can complete different antenna production according to specific reading needs.

One of the characteristics of the present invention is that, for a four-layer printed circuit board, the two conductive signal layers with a dielectric layer in the middle of the top electrical signal layer and the power plane are selected, and there is no wiring and component mounting on the power plane, An unpackaged UHF RFID chip is bonded to the design reserved area located on the periphery of the wiring and component mounting area, and an antenna pattern is made in the top electrical signal layer vertically corresponding to the area of the unpackaged UHF RFID chip, On the unpackaged ultra-high frequency RFID chip, the interface of the antenna is drawn out by a build-up process, and is interconnected with the antenna through the medium layer. Not limited to the electrical signal layer described above, any two adjacent electrical signal layers in the printed circuit board and the dielectric layer in between can be implanted with unpackaged RFID chips and antennas to complete the interconnection.

The second feature of the present invention is: the four-layer printed circuit board includes a packaging substrate for the first level of electronic assembly and a conventional printed circuit board for the second and third level of electronic assembly.

The third feature of the present invention is that, for printed circuit boards with more than four layers, the second electrical signal layer and the third electrical signal layer are selected from top to bottom, and there is a dielectric layer between the two layers, and the third electrical signal layer There is no wiring and component mounting on the layer, and the unpackaged UHF RFID chip is bonded to the design reserved area on the periphery of the wiring and component mounting area, which is vertically corresponding to the unpackaged UHF RFID chip in the second signal layer. The antenna pattern is made in the UHF RFID chip area, and the interface of the antenna is drawn out on the unpackaged UHF RFID chip by a build-up process, and interconnected with the antenna through the dielectric layer. Not limited to the electrical signal layer described above, any two adjacent electrical signal layers in the printed circuit board and the dielectric layer in between can be implanted with unpackaged RFID chips and antennas to complete the interconnection.

The fourth feature of the present invention is: said printed circuit board with more than four layers includes a package substrate for the first-level electronic assembly and a conventional printed circuit board for the second and third-level electronic assembly.

The existing embedded RFID technology generally adopts the method of directly embedding a packaged RFID tag, and the package includes an RFID control memory chip and an antenna. The package itself increases the cost, and the chip area is very small. The area in the package is limited by the antenna design, and the antenna design is limited by the package shape, that is, within a certain proportion of the rectangular shape. The invention embeds an unpackaged RFID control memory chip in the printed circuit board, completes the manufacture of the antenna and the interconnection of the chip and the antenna in the printed circuit board, thereby forming a complete RFID label. While achieving the purpose of embedding RFID for anti-counterfeiting traces, it reduces the packaging cost of RFID tags, can be mass-produced on the entire board at the same time, and can design antennas more freely. The antenna is designed on the printed circuit board without wiring and components. Mounted, located in the design reserved area outside the wiring and component mounting area, with flexible antenna design to adapt to different RFID reading requirements.

Description of drawings

Figure 1 is a schematic diagram of a 4-layer printed circuit board;

Figure 2 is a schematic diagram of a barcode or RFID label mounted on the surface of a printed circuit board;

Figure 3 shows a structure in which RFID tags are embedded inside a printed circuit board;

Figure 4 is an illustration of the design reserved area located on the periphery of the wiring and component mounting area in the printed circuit board;

Fig. 5 is a description of the implanted structure in the present invention;

Fig. 6 is a schematic diagram of antenna production in the present invention, (a) is a zigzag antenna pattern, and (b) is a linear antenna pattern;

Figure 7 is an example of embedding an unpackaged RFID chip on a four-layer printed circuit board;

Figure 8 is an example of embedding an unpackaged RFID chip on a six-layer printed circuit board.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In the present invention, the RFID chip embedding and antenna fabrication are carried out by utilizing the design reserved area on the periphery of the wiring and component mounting area of the printed circuit board without wiring and component mounting.

1) Select a reserved area on one side of the printed circuit board, which is located on the periphery of the wiring and component mounting area, for chip embedding;

2) Select two adjacent conductive signal layers inside the printed circuit board;

3) Embed the RFID chip between the two signal layers during the fabrication of the printed circuit board;

4) The connection between the chip and the upper signal layer is formed by using the build-up process;

5) Complete the production of the antenna pattern on the upper signal layer.

The design reserved area located in the periphery of the wiring and component mounting area mentioned in the above scheme, that is, the area where there is no wiring or component mounting within a certain range from the edge of the board around the board, see Figure 4. In the printed circuit board 400 , the area 401 is the wiring and component placement area, and the surrounding area 402 is the area reserved in the design at the periphery of the wiring and component mounting area. 403 is the selected area where chip implantation is scheduled to be completed. Due to the small size of the RFID chip, within 0.5mm*0.5mm, the area reserved by the general printed circuit board at the periphery of the wiring and component mounting area can complete the chip embedding.

In the selected area 403, chip implantation is performed, as shown in FIG. 5 . A chip 502 is bonded on the signal layer 501 , a build-up process 503 is completed on the 502 , and then a dielectric layer 504 is added according to the printed circuit board manufacturing process, and then a signal layer 505 is pressed. The corresponding area of the signal layer 505 completes the fabrication of the antenna pattern. The antenna fabricated in the signal layer 505 is shown in FIG. 6 , but is not limited to the form shown in FIG. 6 .

In fact, since the UHF RFID frequency band signal will not be shielded by copper, the embedding position of the chip is not limited to the design reserved area outside the wiring and component mounting area. One area for die attach and another layer for antenna fabrication in a suitable separate location, provided no holes are drilled in the die attach area.

Taking a four-layer circuit board as an example, 701, 703, 705, and 707 are electrical signal layers, 702 and 706 are dielectric layers, 704 in the figure is a core board, and for a circuit board with a coreless structure, 704 is a dielectric layer. In the selected design reserved area located on the periphery of the wiring and component mounting area, select the top electrical signal layer 701 and the power plane 703 as the two signal layers needed for RFID embedding, and bond them in the determined area of 703 For the UHF RFID chip 708, an antenna pattern 709 is made at the vertical corresponding position of 701, and the port connected to the antenna is drawn out on the chip 708 by using the build-up process, and the interconnection is completed through the dielectric layer 702 and the antenna 709. After the lamination is completed, the surface of the signal layer 701 is covered with green oil to protect the circuit, and the antenna pattern is also protected by the green oil.

For printed circuit boards with more than four layers, taking a six-layer circuit board as an example, select the second and third signal layers from top to bottom in the selected design reserved area located outside the wiring and component mounting area. The two signal layers required for RFID implantation are bonded with the UHF RFID chip 808 in the determined area of 803, and the antenna pattern 809 is made at the vertical corresponding position of 801, and the antenna is drawn out on the chip 808 by using the layer-building method. The ports pass through the dielectric layer 802 and the antenna 809 to complete the interconnection. Since the antenna is made on the second signal layer, it is not in direct contact with the outside and is well protected.

Claims (4)

1. A method of implanting an RFID tag for radio frequency identification in a printed circuit board, characterized in that: for a four-layer printed circuit board, a conductive signal layer with a dielectric layer is selected in the middle of the top electrical signal layer and the power plane , there is no wiring and component mounting on the power plane, the unpackaged UHF RFID chip is bonded to the design reserved area outside the wiring and component mounting area, and the top electrical signal layer is vertically corresponding to The antenna pattern is made in the unpackaged UHF RFID chip area, and the interface of the antenna is drawn out on the unpackaged UHF RFID chip by using the build-up process, and interconnected with the antenna through the dielectric layer. 2. The basic feature of claim 1 is that the four-layer printed circuit board includes a packaging substrate for the first level of electronic assembly and a conventional printed circuit board for the second and third level of electronic assembly. 3. A method of implanting an RFID tag for radio frequency identification in a printed circuit board, characterized in that: for more than four layers of printed circuit boards, select the second electrical signal layer and the third electrical signal layer from top to bottom, There is a dielectric layer in the middle of the two layers. On the third electrical signal layer, there is no wiring and component mounting, and the unpackaged UHF RFID chip is bonded to the design reserved area outside the wiring and component mounting area. In the second signal layer, the antenna pattern is vertically corresponding to the area of the unpackaged UHF RFID chip, and the interface of the antenna is drawn out on the unpackaged UHF RFID chip by using a layer-up process, and passes through the UHF RFID chip. The dielectric layer and the antenna are interconnected. 4. According to claim 3, its basic feature is that: the printed circuit board with more than four layers includes a packaging substrate for the first level of electronic assembly and a conventional printed circuit for the second and third level of electronic assembly plate.

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