JP4449460B2 - Electronic device manufacturing method and thermocompression bonding apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing an electronic device such as a non-contact type individual identification device equipped with an IC chip, and a thermocompression bonding apparatus for manufacturing such an electronic device by thermocompression bonding.

  In recent years, construction of a non-contact type individual identification system using an RFID (Radio Frequency Identification) tag has been promoted for the purpose of distribution of large quantities of goods, article management, product history management, and the like. In logistics management, in order to attach RFID tags not only to containers and pallets, but also to individual products, tag cost reduction and mass productivity are issues. For this reason, inexpensive IC chips, transmission / reception antennas, Therefore, packaging technology with excellent productivity and low cost is required.

  As a proposal to realize an inexpensive RFID tag, a dipole antenna is connected to the electrodes on each side of a double-sided IC chip in which two external electrodes of the IC chip are provided on the front and back sides of the chip by Usami of Hitachi, Ltd. An inlet having a glass diode package structure is proposed and disclosed in Patent Document 1. Furthermore, Usami et al. Developed a sandwich antenna structure inlet that sandwiches the front and back electrodes of an IC chip with an antenna when a double-sided electrode IC chip is mounted on an excitation slit type dipole antenna. Yes.

  In order to obtain good communication characteristics in a dipole antenna structure having an excitation slit, it is necessary to connect the signal terminal of the IC chip and the ground terminal to the antenna across the slit, so that these two terminals are formed in the same plane. In some cases, as IC chips are miniaturized, high precision is required for alignment between the slit and terminal connection, but in the sandwich antenna structure, the chip is placed with rough positional accuracy on one side of the slit. However, similarly, it is only necessary to connect to the opposite side of the slit with rough positional accuracy, and this structure is suitable for realizing high productivity and cost reduction associated therewith. An example of a sandwich antenna structure is shown in FIG. 8, and an example of a structure when two terminals are in the same plane is shown in FIG.

  In the sandwich antenna structure inlet shown in FIG. 8, (a) is a plan view and (b) is a cross-sectional view taken along line AA ′ of (a). The IC chip 110 in which the electrodes 112 and 113 are formed on the front and back surfaces of the IC chip body 111 has an anisotropic conductive adhesive on the antenna substrate 120 constituted by the base substrate 122 and the antenna circuit 121 by the electrode 112 in the connection portion E. 140 is connected via the conductive particles 142 contained therein, and similarly connected at the connection portion F by the electrode 113 and the short-circuit plate 130 composed of the base substrate 132 and the metal foil 131, and at the connection portion C, the short-circuit plate 130. And the antenna substrate 120 are connected. The connection part F of the upper surface electrode 13 of the IC chip 110 and the connection part C of the antenna substrate 120 are connected across the slit D formed in the antenna circuit 121. The space between the antenna substrate 120 and the short-circuit plate 130 is sealed with a matrix resin 141 of anisotropic conductive adhesive.

9A is a plan view, and FIG. 9B is a cross-sectional view taken along line BB ′ of FIG. The IC chip 111 provided with the two terminals 112 in the same plane has the antenna by the electrode 112 so as to straddle the slit D formed in the antenna circuit 121 of the antenna substrate 120 composed of the base substrate 122 and the antenna circuit 121. It is connected to the substrate 120 and sealed with a sealing material 141.
JP 2002-269520 A ISSCC Digest of Technical Papers, pp.398-399, 2003

  In order to increase productivity and reduce costs when forming a sandwich antenna structure, in FIG. 8, the IC chip 110 and the antenna substrate 120, the IC chip 110 and the short circuit plate 130, and the short circuit plate 130 and the antenna substrate are used. It is desirable to connect 120 simultaneously. In general, a conductive or anisotropic conductive or non-conductive adhesive or a gold-tin alloy is used as a connection material, and thus a thermocompression bonding apparatus is used as a connection tool. However, the connection parts E and F of the IC chip 110 are short-circuited. Since a step corresponding to the thickness of the IC chip 110 occurs in the connection portion C between the plate 130 and the antenna substrate 120, in order to perform thermocompression at the same time, as shown in FIG. It is necessary to form a corresponding step or protrusion 151.

  However, when thermocompression bonding is performed with the pressure-bonding head 150 provided with the step or the protrusion 151, it is necessary to prepare the pressure-bonding head 150 for each thickness of the IC chip 110. Further, when variations occur in the thickness of the IC chip 110 and the thickness of the connection material, pressure variations occur in the two connection portions E, F, and C, which causes a decrease in the reliability of the connection portions. . When thermocompression bonding a plurality of inlets at once in order to increase productivity, the area of the thermocompression bonding head 150 has to be increased as the number of the inlets is increased, and in order to suppress pressure variations among the inlets. Therefore, it is necessary to strictly control the parallelism between the stage and the head of the thermocompression bonding apparatus. Furthermore, when the anisotropic conductive adhesive 140 is used to seal between the antenna substrate 120 and the short-circuit plate 130 at the same time as the electrical connection as shown in FIG. 8, two connections are provided as shown in FIG. Voids 152 are likely to be generated in the matrix resin 141 at portions where the pressure between the portions E, F and C cannot be sufficiently applied. Such voids 152 not only reduce the adhesive strength, but also cause a decrease in reliability from the viewpoint that water tends to accumulate when moisture is absorbed.

  Therefore, the present invention is proposed to solve the above-described problems, and a manufacturing method and an electronic device that can manufacture an electronic device such as an RFID tag inlet having excellent reliability at low cost. An object is to provide a thermocompression bonding apparatus manufactured by thermocompression bonding.

  In order to solve such a problem, the present invention is characterized in that by using a heat conductive medium having flexibility, the device can be changed between two connecting portions having different heights regardless of the thickness of the IC chip. And thermocompression bonding with uniform pressure at the same time.

  That is, according to the present invention, the electrode on one side of the IC chip having electrodes formed on both the front and back sides is connected to one side of the excitation slit on the antenna substrate, and the electrode on the other side of the IC chip and the excitation slit are connected. In the RFID tag inlet manufacturing method in which the antenna substrate portion on the opposite side is connected through a short-circuit plate and the connection portion is formed by thermocompression bonding, the connection between the front and back terminals of the IC chip having different connection heights In order to perform thermocompression bonding at the same time and at a uniform pressure on the connecting portion between the short circuit plate and the antenna substrate, a flexible heat conduction medium (thermocompression head or thermocompression bonding means) is used on the surface of the adherend. It is to thermocompression.

  As a specific method, by using a thermocompression bonding device having a soft rubber having a thickness at least larger than that of the IC chip on the surface of the thermocompression bonding head or a soft foamable rubber, the pressure applied to the two connecting portions can be reduced. It can be made uniform.

  As a more preferred method, a thermocompression bonding head provided with a bag-like container filled with a substance having fluidity at least at the pressure bonding temperature can be used. Here, the fluid substance may be a fluid such as a gas or a liquid, or may be a gel substance such as a silicone resin or agar. The bag-like container may be a fluorine resin excellent in heat resistance, an organic resin rubber obtained by applying a fluorine resin coating to a silicone resin, or a metal plate having a thickness that does not impair the ability to follow a step.

  In addition, by inserting a rubber sheet with a thickness of about 0.05mm to 3mm between the flexible thermocompression bonding head and the object to be bonded, the follow-up to the shape of the object to be bonded is further improved and the pressure is uniform. It is possible to prevent the connection material such as an adhesive from adhering to the thermocompression bonding head. The rubber sheet hardness (Hs JIS A) is preferably about 40 to 90 degrees, and the rubber material is nitrile rubber, chloroprene rubber, ethylene rubber, propylene rubber, butyl rubber, polyurethane rubber, silicon rubber, fluorine Rubber or the like is preferred.

  The flexible heat transfer medium does not need to be fixed to the thermocompression bonding head, and a fluid material is filled inside between a metal block that is a general thermocompression bonding head material and the object to be bonded. The same effect can be obtained by inserting the bag-shaped container.

  As the connecting material for the IC chip, the antenna substrate, the short-circuit plate, and the short-circuit plate and the antenna substrate, a thermosetting adhesive such as a conductive adhesive, an anisotropic conductive adhesive, or a non-conductive adhesive can be used. Among them, the anisotropic conductive adhesive is electrically connected through conductive particles, and the matrix resin is mechanically fixed. However, the excess resin can simultaneously provide a sealing effect between the antenna substrate and the short-circuit plate. High reliability can be expected in this respect, and it is a suitable material.

  It is also possible to form metal bumps on the terminals of the IC chip and to perform metal bonding with a metallized layer different from the antenna material or the antenna material formed on the antenna circuit. As an example of metal bonding, gold-tin bonding can be obtained by applying gold bumps on the IC chip electrodes and tin plating on the copper antenna circuit and thermocompression bonding.

  In the present invention, it is not necessary to define these connection materials as one type, and it is possible to use a combination of the above connection materials in each connection portion.

  According to the present invention, an RFID tag inlet having excellent reliability can be produced at low cost.

  Hereinafter, examples of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1A is a first embodiment of the present invention, and is a schematic view of an RFID tag inlet to which the manufacturing method of the present application is applied, as viewed from the short-circuit plate surface. Moreover, FIG.1 (b) is a cross-sectional schematic of the AA 'part of Fig.1 (a). The structure of the RFID tag will be briefly described with reference to FIGS. In the IC chip 10, electrodes 12 and 13 are formed on the front and back surfaces of the IC chip body 11. The IC chip 10 is connected to the antenna substrate 20 composed of the base substrate 22 and the antenna circuit 21 by the electrode 12 through the conductive particles 42 contained in the anisotropic conductive adhesive 40 at the connection portion E. . Similarly, the short-circuit plate 30 formed of the base substrate 32 and the metal foil 31 and the electrode 13 of the IC chip 10 are connected at the connection portion F, and the short-circuit plate 30 and the antenna substrate 20 are connected at the connection portion C. They are connected by an adhesive 40. That is, the connection portion F of the upper surface electrode 13 of the IC chip and the connection portion C on the antenna substrate are connected across the slit D formed in the antenna substrate 21. The gap between the antenna substrate 20 and the short-circuit plate 30 is sealed with a matrix resin 41 of an anisotropic conductive adhesive 40.

  The first embodiment of the present invention will be described below with reference to the process diagram of FIG.

First, an antenna substrate 20 comprising a base substrate 22 made of polyethylene terephthalate having a thickness of 50 μm and an antenna circuit 21 made of aluminum foil having a thickness of 30 μm was prepared. The size of the antenna substrate 20 is 150 mm in length and 60 mm in width, and 50 antenna circuits 21 having a length of 2.5 mm and a length of 53 mm are formed therein. (Fig. 2 (a))
Next, an anisotropic conductive adhesive film 45 (AC-7106U-25 (Hitachi Chemical Industry) having a width of 2 mm to be the anisotropic conductive adhesive 40 in FIG. 1 is attached to the IC chip mounting portion on the antenna circuit 21 of the antenna substrate 20. The product was laminated at 80 ° C., and the separator film was peeled off. (Fig. 2 (b))
Next, the IC chip 10 having a vertical and horizontal length of 0.48 mm and a thickness of 0.15 mm was temporarily fixed on the anisotropic conductive film 45 using a chip mounter. (Fig. 2 (c))
Next, an anisotropic conductive adhesive having a width of 2 mm is attached to a metal foil surface 31 of a tape-like short-circuit plate 30 having a width of 2 mm, which includes a base substrate 32 made of polyethylene terephthalate having a thickness of 50 μm and a metal foil 31 made of aluminum having a thickness of 30 μm. Film 45 (AC-7106U-25 (manufactured by Hitachi Chemical Co., Ltd.)) was laminated at 80 ° C., and the separator film was peeled off. (Fig. 2 (d))
Next, the short-circuit plate 30 with the anisotropic conductive adhesive film 45 facing the IC chip 10 side and the antenna substrate 20 were aligned and temporarily fixed. Next, the above-described configuration is placed on the stage of a thermocompression bonding apparatus, a rubber sheet is placed thereon, the thermocompression bonding head is lowered from above, and 50 pieces under conditions of a pressure of 5 MPa, a temperature of 180 ° C., and a heating time of 15 seconds. The inlets were thermocompression bonded together. (Fig. 2 (e))
FIG. 3 shows a schematic diagram of the thermocompression bonding head used. A gel-like silicone resin 2 having fluidity is filled inside, and a bag-like container 3 made of a silicone resin processed with a fluororesin is mounted on a hot plate 1 made of SUS. Further, a support 4 is provided around the hot plate to prevent the bag-like container 3 from falling off and to define the effective crimping area. The rubber sheet used was a nitrile rubber sheet having a thickness of 1 mm and a hardness (Hs JIS A) of 75 degrees. FIG. 4 schematically shows a part of the cross section during thermocompression bonding. G in FIG. 4 is a region for one inlet. In the figure, a rubber sheet 5 is sandwiched between the bag-like container 3 and the short-circuit plate 30.

Next, the continuous antenna board | substrate 20 and the short circuit board 30 were cut | disconnected using the press cutting machine, and it divided | segmented for every one, and obtained the inlet. (Fig. 2 (f))
The 50 inlets produced by the above method all obtained normal communication characteristics. Further, three of them were extracted and subjected to cross-sectional observation. As a result, no void was found in the adhesive at all the inlets.

  In order to confirm that electrical connection is obtained at each connection portion E, F, and C of the antenna substrate 20 and the IC chip 10, the IC chip 10 and the short-circuit plate 30, and the short-circuit plate 30 and the antenna substrate 20, the following experiment was performed. Carried out.

  First, a bare silicon chip having the same size as the IC chip 10 of Example 1 and having a vertical and horizontal length of 0.48 mm and a thickness of 0.15 mm is prepared, and electroless nickel is formed on the entire surface with a thickness of about 5 μm. -Gold plating was applied.

  Next, an aluminum circuit 25 having a width of 2.5 mm and a length of 53 mm, which is the same size as the antenna circuit 20 of the first embodiment, is processed into a shape in which the slit is disconnected at the H portion as shown in FIG. In the same arrangement as in Example 1, 50 sheets were formed in a sheet having a length of 150 mm and a width of 60 mm.

  Next, in the process shown in FIGS. 2B to 2F of Example 1, the bare silicon chip plated on the entire surface of the circuit 25 and the short-circuit plate 30 are bonded to the anisotropic conductive adhesive film (AC-7106U). -25 (manufactured by Hitachi Chemical Co., Ltd.)).

  The 50 test pieces produced by the above method have the configuration shown in FIG. 6, and by measuring the electrical resistance between II ′ in FIG. 6A, one of the circuits 25, the silicon chip 15, It can be confirmed that electrical connection is obtained at each of the connection portions E, F, and C of the silicon chip 15 and the short-circuit plate 30 and the short-circuit plate 30 and the other 24 of the circuit 25. In the figure, plating 17 is applied to the entire surface of the silicon chip body 16. As a result of the measurement, a resistance value of 1Ω or less was obtained for all 50 test pieces. Moreover, as a result of extracting three pieces and performing cross-sectional observation, no void was found in the matrix resin 41 of the anisotropic conductive adhesive 40 in all the test pieces.

  The test was performed in the same manner as in Example 2 except that the thickness of the IC chip body 15 was changed to 0.05 mm. As a result, a resistance value of 1Ω or less was obtained for all 50 test pieces. Moreover, as a result of extracting three pieces and performing cross-sectional observation, no void was found in the matrix resin 41 of the anisotropic conductive adhesive 40 in all the test pieces.

[Comparative Example 1]
The IC chip 10, the antenna substrate 20, and the short-circuit plate 30 were prepared in the steps shown in FIGS.

  Next, the antenna substrate 20 on which the IC chip 10 was temporarily fixed and the short-circuit plate 30 with the anisotropic conductive adhesive film 45 facing the IC chip were aligned and temporarily fixed. Next, the above configuration is placed on the stage of a thermocompression bonding apparatus, the rubber sheet used in Example 1 is placed thereon, the thermocompression bonding head is lowered from above, and the pressure is 5 MPa, the temperature is 180 ° C., and the heating time is 15 50 inlets were collectively thermocompression bonded under the conditions of seconds.

  As shown in FIG. 7, the thermocompression bonding apparatus used was equipped with a thermocompression bonding head 50 made of aluminum nitride on which 50 protrusions 51 having the same height as the IC chip 10 and having a height of 0.15 mm were formed.

  Next, the continuous antenna board | substrate 20 and the short circuit board 30 were cut | disconnected using the press cutting machine, and it divided | segmented for every one, and obtained the inlet.

  The 50 inlets produced by the above method all obtained normal communication characteristics. However, three of them were extracted and subjected to cross-sectional observation. As a result, voids were observed in the adhesive with two test pieces.

[Comparative Example 2]
In order to confirm that the electrical connection is obtained at the connection portions E, F, and C of the antenna substrate 20 and the IC chip 10, the IC chip 10 and the short-circuit plate 30, and the short-circuit plate 30 and the antenna substrate 20, in Comparative Example 1 The test was performed in the same manner as in Example 2 except that the thermocompression bonding apparatus used was used. As a result, a resistance value of 1Ω or more was obtained with 5 of the 50 test pieces. However, three of them were extracted and subjected to cross-sectional observation. As a result, voids were observed in the adhesive with two test pieces.

[Comparative Example 3]
When using the IC chip body 11 having a thickness of 0.05 mm, the thermocompression bonding apparatus used in Comparative Example 1 was used to confirm whether or not the connection of each connection portion could be obtained without replacing the thermocompression bonding head. The test was performed in the same manner as in Example 3 except that it was used. As a result, open defects occurred in all 50 specimens. As a result of extracting three of them and observing the cross section, in all the test pieces, connection failure due to insufficient adhesion was observed in the connection portions E, F and C between the IC chip body 11, the antenna substrate 20 and the short circuit plate 30. It was.

The results of Examples 1 to 3 and Comparative Examples 1 to 3 are summarized in Table 1.

  The following effects can be obtained by the present invention. In a method for manufacturing an inlet for a sandwich antenna structure using an IC chip with double-sided electrodes, two inlets having different heights are heated at a uniform pressure by a method in which the inlet is thermocompression bonded through a flexible heat conduction medium. It is possible to crimp. Therefore, it is not necessary to make or replace the thermocompression bonding head every time the thickness of the IC chip is changed, and even when a large area head is used for thermocompression bonding of a plurality of inlets at once, the mounting stage and the head Therefore, it is not necessary to strictly manage the parallelism, so that high productivity can be realized. In addition, stable electrical connection can be obtained by thermocompression bonding each connection portion with a uniform pressure, and excellent connection reliability can be realized. Furthermore, when an anisotropic conductive adhesive is used as the connection material and electrical connection and sealing of the gap between the antenna substrate and the short-circuit plate are performed at the same time, voids inside the adhesive can be suppressed and excellent reliability can be achieved. It is possible to get sex.

The structure of the inlet obtained from Example 1 of this invention is shown, (a) is a top view, (b) is AA 'sectional drawing of (a). It is a figure for demonstrating this invention. It is a figure for demonstrating the thermocompression-bonding head of this invention. It is a figure for demonstrating the state at the time of the thermocompression bonding of this invention. It is a figure for demonstrating the board | substrate used in Example 2 of this invention. It is a figure for demonstrating the structure of the test piece of Example 2 of this invention, (a) is a top view, (b) is JJ 'sectional drawing of (a). It is a figure which shows the thermocompression-bonding head shape used in the comparative example 1. The structure of the conventional inlet is shown, (a) is a top view, (b) is AA 'sectional drawing of (a). The conventional inlet structure is shown, (a) is a top view, (b) is BB 'sectional drawing of (a). It is a figure which shows the conventional thermocompression-bonding head shape. It is a figure for demonstrating the state at the time of the conventional thermocompression bonding.

Explanation of symbols

1: Hot plate 2: Gel-like resin 3: Bag-like container 4: Support 5: Rubber sheet 6: Mounted stage 10: IC chip with double-sided electrode 11: IC chip body 12, 13: External electrode 15: Silicon for measuring connection resistance Chip 16: Bare silicon chip 17: Electroless nickel-gold plating layer 20: Antenna substrate 21: Antenna circuit 22: Base substrate 23, 24: Aluminum circuit 25: Circuit 30: Short-circuit plate 31: Metal foil 32: Base substrate 40: Anisotropic conductive adhesive 41: Matrix resin 42: Conductive particle 45: Anisotropic conductive film 50: Crimp head 51: Protrusion 110: IC chip 111: Conventional IC chip 112: Gold bump 113: Electrode 120: Antenna Substrate 121: Antenna circuit 122: Base substrate 130: Short-circuit plate 131: Metal foil 132: Base substrate 140: Anisotropic conductive adhesive 41: Sealing material 142: Conductive particles 150: Thermocompression bonding head 151: Projection 152: Voids AA ′, BB ′, JJ ′: Cut surfaces C, E, F: Connection part D: Excitation slit G : Range of one inlet H: Disconnection I, I ': Resistance measurement point

Claims (5)

An IC chip formed on a pair of surfaces facing external electrodes; a transmitting / receiving antenna connected to an external electrode on one surface of the IC chip; and an external electrode on the other surface of the IC chip; a short-circuiting plate to electrically connect the IC chip and said receiving antenna, said IC chip and the connecting member for connecting the transmitting and receiving antenna and the short-circuiting plate, for connecting the shorting plate and the receiving antenna In the manufacturing method of the electronic device including the connection member of
The connection between the IC chip and the transmission / reception antenna and the short-circuit plate and the connection between the transmission / reception antenna and the short-circuit plate are simultaneously performed by a thermocompression bonding apparatus having a flexible thermocompression bonding surface at least at a compression temperature. A method for manufacturing an electronic device. In the manufacturing method of the electronic device according to claim 1,
A thermocompression bonding head comprising: a bag-like container filled with a substance having fluidity at least at a crimping temperature at the connection between the IC chip and the transmitting / receiving antenna and the shorting plate; and the connection between the transmitting / receiving antenna and the shorting plate. A method for manufacturing an electronic device, which is performed simultaneously by a thermocompression bonding device provided on the thermocompression bonding surface. In the manufacturing method of the electronic device according to claim 1 or 2,
Insert a sheet-like substance having flexibility at least at the compression temperature into at least one side between the thermocompression bonding surface of the thermocompression bonding apparatus, the constituent material of the electronic device as the object to be bonded, and the thermocompression bonding stage. A method for manufacturing an electronic device. In the manufacturing method of the electronic device according to claim 1,
The connection between the IC chip and the transmission / reception antenna and the short-circuit plate, and the connection between the transmission / reception antenna and the short-circuit plate are a thermocompression bonding head of a thermocompression bonding apparatus, and a constituent material of the electronic device that is a body to be bonded, Manufacturing of an electronic device characterized by being simultaneously performed by inserting a bag-like container filled with a substance having fluidity at least at a pressure bonding temperature between at least one side between the thermocompression bonding stages. Method. In the manufacturing method of the electronic device according to any one of claims 1 to 4,
The connection between the IC chip and the transmission / reception antenna and the short-circuit plate, and the connection between the transmission / reception antenna and the short-circuit plate are at least a conductive adhesive, an anisotropic conductive adhesive, a non-conductive adhesive, or a metal joint. A method of manufacturing an electronic device, which is performed by one or a combination of two or more.

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