JP2019083285A - Circuit substrate, wireless communication device, and fabricating method for circuit board - Google Patents

Abstract

To prevent, in a circuit board having conductor patterns on a main surface opposite to another main surface on which an electronic component is mounted, mounted failure of the electronic component while providing the conductor patterns highly densely.SOLUTION: A circuit board 12 comprises: a base board 26 having first and second main surfaces 26a, 26b opposite each other in a thickness direction; a conductor pattern 28 provided on the first main surface 26a of the base board 26; a plurality of electrode pads 44Aa, 44Ba provided on the second main surface 26b of the base board 26; and an electronic component 16 having a plurality of to-be-mounted electrodes 16a, 16b respectively connected opposite to the plurality of electrode pads 44Aa, 44Ba. The conductor pattern 28 has a portion overlapping a portion of the electronic component 16 so as not to overlap the plurality of to-be-mounted electrodes 16a, 16b, in a plan view of the base board 26.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a circuit board on which electronic components are mounted, a wireless communication device provided with the circuit board, and a method of manufacturing the circuit board.

  The smaller the device having the circuit board, the smaller the size and thickness of the circuit board, and the conductor patterns formed on the circuit board are provided with high density. Therefore, as described in, for example, Patent Document 1, part of the conductor pattern overlaps the electronic component mounted on the circuit board in plan view (view in the thickness direction) of the circuit board.

International Publication No. 2016/098379

  A conductor pattern may be provided with high density on the main surface opposite to the main surface of the circuit board on which the electronic component is mounted. However, in this case, mounting failure of the electronic component may occur depending on the pattern layout of the conductor pattern and the relationship with the mounting method.

  Therefore, according to the present invention, in a circuit board having a conductor pattern formed on the main surface opposite to the main surface on which the electronic component is mounted, occurrence of mounting failure of the electronic component while providing the conductor pattern at high density To reduce the problem.

In order to solve the above technical problems, according to one aspect of the present invention,
A substrate comprising first and second major surfaces opposed in the thickness direction;
A conductor pattern provided on the first main surface of the substrate;
A plurality of electrode pads provided on the second main surface of the substrate;
An electronic component provided with a plurality of mounting electrodes respectively connected to be opposed to the plurality of electrode pads;
A circuit board is provided, wherein the conductor pattern does not overlap any of the plurality of mounting electrodes in a plan view of the substrate, and has a portion overlapping the portion of the electronic component.

Also, according to another aspect of the present invention,
Circuit board,
And an antenna mounted on the circuit board,
The circuit board is
A substrate comprising first and second major surfaces opposed in the thickness direction;
A conductor pattern provided on the first main surface of the substrate;
A plurality of electrode pads provided on the second main surface of the substrate;
An electronic component provided with a plurality of mounting electrodes respectively connected to be opposed to the plurality of electrode pads;
The conductor pattern does not overlap any of the plurality of mounting electrodes in a plan view of the substrate, and has a portion overlapping the portion of the electronic component,
A wireless communication device is provided, characterized in that the conductor pattern is part of the antenna.

Furthermore, according to a different aspect of the invention,
A method of manufacturing a circuit board on which an electronic component having a plurality of mounting electrodes is mounted, comprising:
A substrate having first and second main surfaces opposed in the thickness direction, a conductor pattern provided on the first main surface, and a plurality of electrode pads provided on the second main surface Prepare
The electronic component is disposed on the substrate such that the plurality of mounting electrodes face the electrode pad,
The plurality of mounting electrodes are crimped to the electrode pad by pressing the electronic component toward the substrate.
In the method of manufacturing a circuit board, the conductor pattern does not overlap any of the plurality of mounting electrodes in plan view of the substrate, and has a portion overlapping the portion of the electronic component. Ru.

  According to the present invention, in a circuit board on which a conductor pattern is formed on the main surface opposite to the main surface on which the electronic component is mounted, occurrence of mounting failure of the electronic component while providing the conductor pattern at high density Can be suppressed.

A perspective view of a wireless communication device according to an embodiment of the present invention Sectional view of wireless communication device along line A-A of FIG. 1 Equivalent circuit diagram of wireless communication device A perspective view showing an internal configuration of a terminal block of a wireless communication device A perspective view of a circuit board of a wireless communication device as viewed from the first main surface side The perspective view of the circuit board seen from the 2nd principal surface side A perspective view of the circuit board with the resist removed, viewed from the first main surface side Top view of circuit board showing application position of molten resin bonding terminal block and circuit board A perspective view of the circuit board with the resist removed, viewed from the second main surface side Top view of a portion of the second major surface of the substrate A diagram showing how an RFIC chip is ultrasonically pressed to a substrate in the present embodiment. The figure which shows the circuit board of a comparative example The figure which shows a mode that ultrasonic bonding is carried out to a board | substrate in a comparative example in a RFIC chip. Partial cross-sectional view of a circuit board according to another embodiment of the present invention A partial cross-sectional view of a circuit board according to still another embodiment of the present invention

  A circuit board according to one aspect of the present invention includes a substrate including first and second main surfaces opposed in a thickness direction, a conductor pattern provided on the first main surface of the substrate, and a second of the substrate A plurality of electrode pads provided on the main surface of the substrate, and an electronic component provided with a plurality of mounting electrodes respectively facing and connected to the plurality of electrode pads, the conductor pattern being the substrate The semiconductor device is characterized in that it has a portion which does not overlap with the plurality of mounting electrodes and which overlaps with the portion of the electronic component.

  According to this aspect, in the circuit board in which the conductor pattern is formed on the main surface opposite to the main surface on which the electronic component is mounted, occurrence of mounting failure of the electronic component while providing the conductor pattern at high density Can be suppressed.

  For example, the conductor pattern includes a first linear conductor portion and a second linear conductor portion, and the plurality of mounting electrodes include a first mounting electrode, and the first mounting electrode However, in the plan view, it may be located between the first linear conductor portion and the second linear conductor portion.

  For example, the conductor pattern further includes a third linear conductor portion, the plurality of mounting electrodes further include a second mounting electrode, and the second mounting electrode is viewed in plan view, The first linear conductor portion is located between the first linear conductor portion and the third linear conductor portion, and the first linear conductor portion is the first mounting electrode and the second in a plan view. And the mounting electrode.

  A wireless communication device according to another aspect of the present invention includes a circuit board and an antenna mounted on the circuit board, wherein the circuit board includes first and second main surfaces opposed in the thickness direction. A conductor pattern provided on the first main surface of the substrate, a plurality of electrode pads provided on the second main surface of the substrate, and a plurality of electrode pads facing each other. Component having a plurality of mounting electrodes, and the conductor pattern does not overlap the plurality of mounting electrodes in a plan view of the substrate, and has a portion overlapping the portion of the electronic component The conductor pattern is a part of the antenna.

  According to this aspect, in the circuit board in which the conductor pattern is formed on the main surface opposite to the main surface on which the electronic component is mounted, occurrence of mounting failure of the electronic component while providing the conductor pattern at high density Can be suppressed.

  A method of manufacturing a circuit board according to another aspect of the present invention is a method of manufacturing a circuit board on which an electronic component including a plurality of mounting electrodes is mounted, the first and second main surfaces facing each other in the thickness direction A substrate provided with a conductive pattern on the first main surface and provided with a plurality of electrode pads on the second main surface, the plurality of mounting electrodes being opposed to the electrode pad The electronic components are disposed on the substrate so that the plurality of mounting electrodes are crimped to the electrode pads by pressing the electronic components toward the substrate, and the conductor pattern is the substrate. In a plan view, the plurality of mounting electrodes do not overlap each other, and have a portion overlapping the portion of the electronic component.

  According to this aspect, in the circuit board in which the conductor pattern is formed on the main surface opposite to the main surface on which the electronic component is mounted, occurrence of mounting failure of the electronic component while providing the conductor pattern at high density Can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a wireless communication device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA shown in FIG. And FIG. 3 is an equivalent circuit diagram of the wireless communication device. In the drawings, the X-Y-Z coordinate system is for the purpose of facilitating the understanding of the invention, and does not limit the invention.

  In the case of the present embodiment, the wireless communication device 10 is, for example, an RFID (Radio-Frequency Identification) tag that performs wireless communication at a frequency of the HF band, and includes the circuit board 12 and the coil antenna 14. Although details will be described later, an RFIC (Radio-Frequency Integrated Circuit) chip 16 as an electronic component is mounted on the circuit board 12. Further, in the case of the present embodiment, the capacitor chip 18 is mounted on the circuit board 12 in order to achieve impedance matching between the RFIC chip 16 and the coil antenna 14, which will be described in detail later. In the case where impedance matching can be performed by the internal capacitance of the RFIC chip 16, the capacitor chip 18 can be omitted.

  Such a wireless communication device 10 communicates with an external wireless communication device (for example, a reader / writer device) through the magnetic field coupling via the coil antenna 14. For example, when a magnetic flux from an external wireless communication device links the coil antenna 14, an electromotive force is generated, and the RFIC chip 16 is driven by the electromotive force. The driven RFIC chip 16 transmits the data stored in the storage unit via the coil antenna 14.

  From here, details of the configuration of the wireless communication device 10 will be described.

  As shown in FIG. 1, in the case of the present embodiment, the wireless communication device 10 includes a circuit board 12 and a terminal block 20 attached to the circuit board 12.

  FIG. 4 is a perspective view showing an internal configuration of the terminal block. 5 and 6 are perspective views of the circuit board 12.

  As shown in FIG. 4, the terminal block 20 includes a block-shaped main body 22 made of, for example, a resin material, and a plurality of conductor members 24 A to a part of the coil antenna 14 embedded in the main body 22. It has 24F. Each of the plurality of conductor members 24A to 24F is a gate-shaped member made of a conductor such as copper, for example. The plurality of conductor members 24A to 24F are arranged in a spaced state (arranged in the Y-axis direction). Each of the plurality of conductor members 24A to 24F includes one end 24Aa to 24Fa and the other end 24Ab to 24Fb for connection to the conductor pattern on the circuit board 12, which will be described in detail later.

  As shown in FIGS. 5 and 6, the circuit board 12 has a substrate 26 provided with a first major surface 26a and a second major surface 26b opposed in the thickness direction (Z-axis direction). In the case of the present embodiment, the substrate 26 is a thin substrate such as, for example, an FR4 substrate. The substrate 26 may be a resin substrate. In the case of the present embodiment, the substrate 26 has a thickness of, for example, 200 μm.

  As shown in FIG. 5, a conductor pattern 28 connected to the plurality of conductor members 24A to 24F of the terminal block 20 is provided on the first main surface 26a of the substrate 26. The conductor pattern 28 is a circuit pattern manufactured from a conductor such as copper or gold, for example. For example, the conductor pattern 28 is formed on the first main surface 26 a of the substrate 26 by pattern printing or the like. In the case of the present embodiment, the conductor pattern 28 is formed with a thickness of 35 μm. In the case of the present embodiment, the conductor pattern 28 is partially covered and protected by the resist 30.

  Specifically, as shown in FIG. 7 in which the resist is omitted, the conductor pattern 28 includes a plurality of linear conductor portions 32A to 32G. Each of the plurality of linear conductors 32A to 32G is a part of the coil antenna 14 and extends in the longitudinal direction (X-axis direction) of the circuit board 12. Each of the plurality of linear conductors 32A to 32G includes one end 32Aa to 32Ga and the other end 32Ab to 32Gb. These one end and the other end are exposed without being covered by the resist 30 in order to connect with the conductor members 24A to 24F of the terminal block 20 as shown in FIG.

  4 and 7, the other end 32Ab of the linear conductor portion 32A in the conductor pattern 28 is connected to the other end 24Ab of the conductor member 24A in the terminal block 20. One end 24Aa of the conductor member 24A is connected to one end 32Ba of the linear conductor portion 32B in the conductor pattern 28.

  The other end 32Bb of the linear conductor portion 32B is connected to the other end 24Bb of the conductor member 24B in the terminal block 20. One end 24Ba of the conductor member 24B is connected to one end 32Ca of the linear conductor portion 32C in the conductor pattern 28.

  The other end 32Cb of the linear conductor portion 32C is connected to the other end 24Cb of the conductor member 24C in the terminal block 20. One end 24Ca of the conductor member 24C is connected to one end 32Da of the linear conductor portion 32D in the conductor pattern 28.

  The other end 32Db of the linear conductor portion 32D is connected to the other end 24Db of the conductor member 24D in the terminal block 20. One end 24Da of the conductor member 24D is connected to one end 32Ea of the linear conductor portion 32E in the conductor pattern 28.

  The other end 32Eb of the linear conductor portion 32E is connected to the other end 24Eb of the conductor member 24E in the terminal block 20. One end 24Ea of the conductor member 24E is connected to one end 32Fa of the linear conductor portion 32F in the conductor pattern 28.

  The other end 32Fb of the linear conductor portion 32F is connected to the other end 24Fb of the conductor member 24F in the terminal block 20. One end 24Fa of the conductor member 24F is connected to one end 32Ga of the linear conductor portion 32G in the conductor pattern 28.

  By thus connecting the plurality of linear conductor portions 32A to 32G in the conductor pattern 28 and the plurality of conductor members 24A to 24F in the terminal block 20, it is possible that the current flows helically as shown in FIG. A helical coiled coil antenna 14 is formed which comprises six possible loops. Note that one end 32Aa of the linear conductor portion 32A and the other end 32Gb of the linear conductor portion 32G in the conductor pattern 28 function as both ends of the coil antenna 14.

  In order to maintain the connection between the plurality of linear conductor portions 32A to 32G in the conductor pattern 28 and the plurality of conductor members 24A to 24F in the terminal block 20, the terminal block 20 is joined to the circuit board 12. Specifically, as shown in FIG. 2, the terminal block 20 and the circuit board 12 are joined via a resin material (for example, a resin-based adhesive) 34.

  FIG. 8 shows the application area AR of the resin material (melted resin material) 34 on the circuit board 12 (substrate 26). By applying the resin material 34 to the application area AR and bringing the terminal block 20 into contact with the circuit board 12, the resin material 34 is spread over the entire gap between the circuit board 12 and the terminal block 20. Thereafter, the resin material 34 is cured to bond the circuit board 12 and the terminal block 20.

  In the case of the present embodiment, as shown in FIG. 8, the resist 30 for protecting the conductor pattern 28 does not cover the first main surface 26 a in the entire width direction (Y-axis direction) of the substrate 26. Specifically, it is provided on the first main surface 26 a of the substrate 26 in a size that can cover the conductor pattern 28 as necessary. Therefore, both end side portions in the width direction of the first main surface 26 a are exposed without being covered by the resist 30. The application area AR of the resin material 34 includes not only the resist 30 but also the first major surface 26 a of the substrate 26. Thereby, the resin material 34 can be in direct contact with the first major surface 26 a of the substrate 26. As a result, the terminal block 20 has its central portion in the width direction joined to the resist 30 through the resin material 34, and its both lateral portions on the first major surface 26 a of the substrate 26 through the resin material 34. It is joined. As a result, the terminal block 20 is firmly joined to the circuit board 12.

  In the case of the present embodiment, as shown in FIG. 8, each of the plurality of linear conductor portions 32B to 32F in the conductor pattern 28 goes from the both ends in the longitudinal direction (X axis direction) of the circuit board 12 toward the center. It extends straight in the longitudinal direction and cranks at the longitudinal center of the circuit board 12. Therefore, two regions SS in which the conductor pattern 28 does not exist appear in central symmetry of the first major surface 26a. These areas SS are larger than other areas where the conductor pattern 28 does not exist. Therefore, by joining these regions SS to the terminal block 20 via the resin material 34, the terminal block 20 is joined to the circuit board 12 with uniform joint strength.

  As shown in FIG. 6, the RFIC chip 16 and the capacitor chip 18 are mounted on the second main surface 26 b of the substrate 26.

  Conductor patterns 40 connected to the RFIC chip 16 and the capacitor chip 18 are provided on the second main surface 26 b of the substrate 26. The conductor pattern 40 is also partially covered and protected by the resist 42, similarly to the conductor pattern 28 on the first major surface 26a.

  As shown in FIG. 9 in which the resist (and the RFIC chip etc.) is omitted, the conductor pattern 40 is a circuit pattern made of a conductor such as copper or gold in the same manner as the conductor pattern 28 on the first main surface 26a. It is. For example, the conductor pattern 40 is formed on the second major surface 26 b of the substrate 26 by pattern printing or the like. In the case of the present embodiment, the conductor pattern 40 is formed with a thickness of 35 μm.

  Further, in the case of the present embodiment, the conductor pattern 40 includes the connection conductor portions 44A and 44B.

  The connection conductor portions 44A and 44B in the conductor pattern 40 are conductors for connecting the RFIC chip 16 and the capacitor chip 18 to the coil antenna 14.

  The connection conductor portion 44A includes an electrode pad 44Aa for connecting to the RFIC chip 16 and an electrode pad 44Ab for connecting to the capacitor chip 18. The connection conductor portion 44A is connected to one end 32Aa of the linear conductor portion 32A in the conductor pattern 28 on the first major surface 26a via the interlayer connection conductor 46 such as a via hole conductor. That is, the connection conductor portion 44A is connected to one end of the coil antenna 14.

  The connection conductor portion 44 B includes an electrode pad 44 Ba for connection to the RFIC chip 16 and an electrode pad 44 Bb for connection to the capacitor chip 18. The connection conductor portion 44B is connected to the other end 32Gb of the linear conductor portion 32G in the conductor pattern 28 on the first main surface 26a via the interlayer connection conductor 48 such as a via hole conductor. That is, the connection conductor portion 44B is connected to the other end of the coil antenna 14.

  As shown in FIG. 10, which is a top view of a portion of the second main surface 26b of the substrate 26, the RFIC chip 16 includes four mounting electrodes 16a to 16b. Among the four mounting electrodes, as shown in FIG. 2, the mounting electrode 16a is connected to be opposed to the electrode pad 44Aa, and the mounting electrode 16b is connected to be opposed to the electrode pad 44Ba. As shown in FIG. 10, the remaining mounting electrodes 16c and 16d are connected to the dummy electrode 50 independent of the connection conductor portions 44A and 44B in the case of the present embodiment.

  As shown in FIGS. 1 and 2, the RFIC chip 16 and the capacitor chip 18 connected to such connection conductor portions 44A and 44B are covered and protected by a protective layer 52 of resin.

  From here, a connection method between the mounting electrodes 16 a to 16 d of the RFIC chip 16 and the electrode pads 44 Aa and 44 Ba of the conductor pattern 40 and the dummy electrode 50 will be described.

  In the case of the present embodiment, the connection between the mounting electrodes 16a to 16d of the RFIC chip 16 and the electrode pads 44Aa and 44Ba of the conductor pattern 40 and the dummy electrode 50 is established by ultrasonic pressure bonding. In the case of the present embodiment, the capacitor chip 18 and the electrode pads 44Ab and 44Bb are connected via solder.

  FIG. 11 shows how an RFIC chip is mounted on a substrate. As shown in FIG. 11, ultrasonic pressure bonding between the RFIC chip 16 and the substrate 26 is performed using the ultrasonic welding apparatus 100.

  The ultrasonic welding apparatus 100 has an anvil 102 for supporting the substrate 26 and a horn 104 that vibrates while pressing the RFIC chip 16 against the substrate 26. The horns 104 vibrate at a predetermined amplitude stroke WS and at a predetermined frequency while pressing the RFIC chip 16 with a predetermined pressing force PF, whereby the mounting electrodes 16a to 16d of the RFIC chip 16 are electrode pads 44Aa, 44Ba, and Ultrasonic pressure is applied to the dummy electrode 50. For example, the horn 104 vibrates at an amplitude stroke WS of 1.40 to 1.67 μm and a frequency of 60 Hz while pressing the RFIC chip 16 with a pressing force PF of 4.0 to 7.5N. In the case of the present embodiment, the horn 104 of the ultrasonic welding apparatus 100 vibrates in the width direction (Y-axis direction) of the substrate 26 which is the short direction, but the extension direction of the substrate 26 which is the longitudinal direction ( It may vibrate in the X axis direction).

  The mounting electrodes 16a to 16d of the RFIC chip 16 and the conductor patterns 40 (that is, the electrode pads 44Aa and 44Ba) to be ultrasonically press-bonded are preferably made of the same material in order to obtain higher bonding strength. . For example, both the mounting electrode and the electrode pad are made of gold or copper. If different, the electrode pad may be plated with the same material as that of the mounting electrode. For example, the electrode pad is made of copper, nickel, silver, or aluminum, and a gold or copper plating layer is formed on the surface thereof.

  In order to properly mount the RFIC chip 16 on the substrate 26, that is, to suppress the occurrence of mounting failure of the RFIC chip 16, the first main surface opposite to the second main surface 26b on which the RFIC chip 16 is mounted The pattern layout of the conductor pattern 280 provided on the main surface 26a is taken into consideration.

  Specifically, as shown in FIG. 10, with respect to the plurality of mounting electrodes 16 a to 16 d of the RFIC chip 16 in plan view of the substrate 26 (view in the thickness direction of the substrate 26 (view in the Z-axis direction)), The conductor patterns 28 on the first major surface 26a do not overlap. However, in order to provide the conductor pattern 28 at a high density, the portion of the conductor pattern 28, that is, the linear conductor portion 32D does not overlap the plurality of mounting electrodes 16a to 16d, and the RFIC chip excluding these mounting electrodes Overlapping 16 parts. In the case of this embodiment, the remaining linear conductors other than the linear conductor 32D do not overlap the RFIC chip 16.

  In the case of the present embodiment, in order to realize such a layout of the conductor patterns 28, the width W1 of the portion 32Dc of the linear conductor portion 32D overlapping the RFIC chip 16 is smaller than the width W0 of the other portions. It is done. Thus, the linear conductor portion 32D can overlap the RFIC chip 16 while avoiding the plurality of mounting electrodes 16a to 16d in a plan view of the substrate 26 (view in the Z-axis direction). In addition, the pitch distance between the linear conductor 32D overlapping the RFIC chip 16 and the adjacent linear conductors 32C and 32E is partially different. That is, in order to avoid the plurality of mounting electrodes 16a to 16d, the pitch interval p1 of one portion is made larger than the pitch interval p0 of the other portion. Thus, the mounting electrodes 16b and 16c are positioned between them without overlapping the linear conductors 32D and 32E in plan view of the substrate 26, and the mounting electrodes 16a and 16d are linear conductors 32C and 32D. Can be located between them without overlapping.

  As described above, the reason for laying out the conductor pattern 28 on the first main surface 26 a so as not to overlap the plurality of mounting electrodes 16 a to 16 d of the RFIC chip 16 in plan view of the substrate 26 (view in the Z-axis direction) will be described. Do. The reason will be described with reference to the circuit board of the comparative example.

  FIG. 12 shows a circuit board of a comparative example in which an RFIC chip is mounted on the substrate of the comparative example. The circuit board of the comparative example is substantially the same as the circuit board 12 of the present embodiment except that the pattern layout of the conductor patterns provided on the first main surface of the board is different.

  As shown in FIG. 12, unlike the circuit board 12 of the present embodiment, in the case of the circuit board 212 of the comparative example, in the conductor pattern 228 provided on the first main surface 26 a of the board 26, a linear conductor portion While 232 B overlaps the mounting electrode 16 a of the RFIC chip 16 in a plan view of the substrate 26 (view in the Z-axis direction), the linear conductor portion 232 C overlaps the mounting electrode 16 b.

  In the case of the circuit board 212 of the comparative example, as shown in FIG. 13, when the horn 104 of the ultrasonic welding apparatus 100 presses the RFIC chip 16 toward the substrate 26, the electrode pads 44Aa, 44Ba facing the mounting electrodes 16a, 16b. The local force is applied to Depending on the thickness of the substrate or mounting electrode, it may be bent. As a result, a mounting failure of the RFIC chip 16 occurs without the mounting electrodes 16a and 16b being properly crimped to the electrode pads 44Aa and 44Ba. For example, a defect in which the mounting electrode is not crimped to the electrode pad over the whole, or a defect in which the distribution of bonding strength is not uniform even if the mounting electrode is crimped to the electrode pad over the whole. If such mounting failure occurs, the resistance value between the RFIC chip and the conductor pattern deviates from the designed value, and as a result, the wireless communication device can not have the designed communication characteristics.

  Specifically, such a mounting failure is caused by the linear conductor portions 232A to 232D being pushed toward the substrate 26 by the reaction force from the anvil 102 corresponding to the pressing force of the horn 104 of the ultrasonic welding apparatus 100. Thus, the local force is applied to the substrate 26 (that is, the substrate is not supported by a uniform force throughout). Such local force is generated because the first main surface 26 a side of the substrate 26 is not a flat surface but an uneven surface due to the presence of the plurality of linear conductor portions 232A to 232D. In the case of the circuit board 212 of the comparative example, the surface 30a of the resist 30 has unevenness due to the presence of the linear conductor portions 232A to 232D.

  In particular, since the linear conductor portions 232B and 232C overlap the mounting electrodes 16a and 16b of the RFIC chip 16 in a plan view of the substrate 26 (view in the Z-axis direction), they are crimped opposite to the mounting electrodes 16a and 16b. Due to the fact that a local force is applied (transferred) to the electrode pads 44Aa and 44Ba, a mounting failure occurs. Furthermore, it is because the linear conductor portions 232B and 232C overlap with parts of the mounting electrodes 16a and 16b in plan view of the substrate 26.

  Also in the circuit board 12 of the present embodiment shown in FIG. 11, the linear conductors 32B to 32F are pushed toward the substrate 26 by the reaction force from the anvil 102 corresponding to the pressing force of the horn 104 of the ultrasonic welding apparatus 100. , Thereby applying a local force to the substrate 26. However, since there is no linear conductor portion overlapping the mounting electrodes 16a and 16b of the RFIC chip 16 in a plan view of the substrate 26 (view in the Z-axis direction), the electrodes crimped to face the mounting electrodes 16a and 16b Substantially no local force is applied to the pads 44Aa, 44Ba. Therefore, mounting defects such as those occurring in the circuit board 212 of the comparative example shown in FIGS. 12 and 13 are unlikely to occur, and the mounting electrodes 16a, 16b are appropriately crimped to the electrode pads 44Aa, 44Ba.

Table 1 shows the mounting defect rate which occurs in the circuit board 12 (example) of the present embodiment shown in FIG. 11 and the mounting defect which occurs in the circuit board 212 (comparative example) of the comparative example shown in FIG. 12 and FIG. It shows the rate. The frequency of the horn in the ultrasonic welding apparatus at this time is 60 Hz, and the amplitude is 1.45 μm. Moreover, the pressure of a horn is 5.0N and 6.0N. Furthermore, the number of samples of each of the example and the comparative example is 96.

  As shown in Table 1, mounting defects that do not occur in the circuit board 12 of the present embodiment occur in the case of the circuit board 212 in the comparative example, three in the pressing force of 5.0 N and five in the pressing force of 6.0 N. ing. Also, the higher the pressure on the horn, the higher the mounting failure rate.

  From the results shown in Table 1, as in the present embodiment, the first main is not to overlap the mounting electrodes 16 a and 16 b of the RFIC chip 16 on the second main surface 26 b in plan view of the substrate 26. By providing the conductor pattern 40 on the surface 26a, it is apparent that the occurrence of the mounting failure of the RFIC chip 16 is suppressed.

  In the circuit board 212 of the comparative example shown in FIG. 12, the resist 30 for protecting the conductor pattern 228 is thickened until its surface 30a becomes flat to suppress the local force from being applied to the substrate 26, thereby It is also conceivable to suppress the occurrence of mounting defects of the RFIC chip. However, in that case, the overall thickness of the circuit board 212 is increased, and the miniaturization of the electronic device provided with the circuit board 212 is hindered.

  According to the present embodiment, in the circuit board 12 in which the conductor pattern 28 is formed on the first main surface 26 a opposite to the second main surface 26 b on which the RFIC chip 16 is mounted, While providing the conductor patterns 28 at a high density, it is possible to suppress the occurrence of the mounting failure of the RFIC chip 16.

  As mentioned above, although the present invention was described with the above-mentioned embodiment, the embodiment of the present invention is not limited to this.

  For example, in the case of the first embodiment described above, as shown in FIG. 1, the wireless communication device 10 has a helical coiled coil antenna 14 having six loops, but the embodiment of the present invention Not exclusively. For example, it may be a coil antenna having seven or more or five or less loops.

  FIG. 14 shows a circuit board used for a wireless communication device having a coil antenna having two loops according to another embodiment of the present invention.

  As shown in FIG. 14, in the case of a wireless communication device having a coil antenna comprising two loops, the conductor pattern 328 on the first major surface 26 a of the substrate 26 of the circuit board 312 is a line that is a part of the coil antenna Conductor portions 332A, 332B. In this case, one of the linear conductor portions 332A is a plurality of mounting electrodes 16a and 16b of the RFIC chip 16 (in addition to the mounting electrodes 16c and 16d (not shown) in a plan view of the substrate 26 (view in the Z-axis direction)). It does not overlap with respect to FIG. The other linear conductor portion 332 B does not overlap the RFIC chip 16.

  As shown in FIG. 14, the resist 30 covering the two linear conductors 332A and 332B is formed on all of the plurality of mounting electrodes 16a to 16d of the RFIC chip 16 in plan view of the substrate 26 (view in the Z-axis direction). Preferably, they are provided on the substrate 26 so as to overlap. Thus, the RFI chip 16 is supported by the resist 30 when pressed by the horn of the ultrasonic welding apparatus. For example, when there is no resist overlapping the mounting electrode 16a, the electrode pad 44Aa facing the mounting electrode 16a bends toward the anvil so as to escape from the horn, and the contact pressure between the mounting electrode 16a and the electrode pad 44Aa is It may be short. As a result, mounting failure may occur.

  Further, the antenna of the wireless communication device according to the embodiment of the present invention is not limited to the coil antenna used in the frequency of the HF band. For example, it may be a loop antenna (antenna equipped with one loop) used at frequencies in the UHF band, or a pole antenna such as a dipole antenna.

  FIG. 15 shows a circuit board for use in a wireless communication device having a loop antenna according to another embodiment of the present invention.

  As shown in FIG. 15, in the case of a wireless communication device having a loop antenna, the conductor pattern 428 on the first main surface 26a of the substrate 26 of the circuit board 412 is a linear conductor portion 428A that is a part of the coil antenna. Including. In this case, the linear conductor portion 428A is a plurality of mounting electrodes 16a and 16b of the RFIC chip 16 (in addition to the mounting electrodes 16c and 16d (not shown) in a plan view of the substrate 26 (viewing in the Z-axis direction)). Do not overlap))), located between them.

  In the case of a wireless communication device having a pole antenna, the linear conductor portion 428A constitutes the entire pole antenna. In this case, the terminal block shown in FIG. 3 is not necessary.

  Furthermore, in the case of the above-described embodiment, the conductor pattern 28 on the first main surface 26a of the substrate 26 is protected by the resist 30, and the conductor pattern 40 on the second main surface 26b is protected by the resist 42. . However, the embodiment of the present invention is not limited to this. If the circuit board is housed, for example, in a casing or a housing of a wireless communication device, the resist for protecting the conductor pattern may be omitted.

  Furthermore, in the case of the above-described embodiment, as shown in FIG. 10, the RFIC chip 16 includes the four mounting electrodes 16a to 16d, but the embodiment of the present invention is not limited to this. The plurality of mounting electrodes provided in the RFIC chip may be two, six or more, or any other number.

  In addition, in the case of the above-described embodiment, as shown in FIG. 10, linear shapes positioned between the plurality of mounting electrodes 16a to 16d of the RFIC chip 16 in a plan view of the substrate 26 (view in the Z-axis direction). Although the number of conductors is one, the embodiment of the present invention is not limited to this. A plurality of linear conductors may be located between the plurality of mounting electrodes in a plan view of the substrate.

  In addition, in the case of the above-described embodiment, as shown in FIG. 11, the plurality of mounting electrodes 16a to 16d of the RFIC chip 16, the electrode pads 44Aa and 44Ba of the substrate 26, and the dummy electrode 50 are ultrasonically crimped. Although crimped, the embodiment of the present invention is not limited thereto. For example, the mounting electrode and the electrode pad may be pressure bonded via a conductive adhesive or a thermocompression bonding adhesive.

  Furthermore, the wireless communication device according to the above-described embodiment is a so-called RFID tag, and includes an RFIC chip as an electronic component, but the embodiment of the present invention is not limited thereto. Moreover, the circuit board of the above-mentioned embodiment can be used also by devices other than a wireless communication device.

  That is, in a broad sense, the circuit board according to the embodiment of the present invention includes a substrate provided with first and second main surfaces opposed in the thickness direction, and a conductor provided on the first main surface of the substrate It has a pattern, a plurality of electrode pads provided on the second main surface of the substrate, and an electronic component provided with a plurality of mounting electrodes respectively facing and connected to the plurality of electrode pads. The conductive pattern does not overlap any of the plurality of mounting electrodes in a plan view of the substrate, and has a portion overlapping the portion of the electronic component.

  While several embodiments according to the present invention have been described above, further embodiments according to the present invention may be combined with at least one other embodiment as a whole or in part with one embodiment. It is clear to the person skilled in the art that it is possible.

  The present invention is applicable to a circuit board in which a conductor pattern is formed on the main surface opposite to the main surface on which the electronic component is mounted.

12 circuit board 16 electronic component (RFIC chip)
16a mounting electrode 16b mounting electrode 26 substrate 26a first main surface 26b second main surface 28 conductor pattern 44Aa electrode pad 44Ba electrode pad

Claims (5)

A substrate comprising first and second major surfaces opposed in the thickness direction;
A conductor pattern provided on the first main surface of the substrate;
A plurality of electrode pads provided on the second main surface of the substrate;
An electronic component provided with a plurality of mounting electrodes respectively connected to be opposed to the plurality of electrode pads;
A circuit board, wherein the conductor pattern does not overlap any of the plurality of mounting electrodes in plan view of the substrate, and has a portion overlapping the portion of the electronic component. The conductor pattern includes a first linear conductor portion and a second linear conductor portion;
The plurality of mounting electrodes include a first mounting electrode,
The circuit board according to claim 1, wherein the first mounting electrode is located between the first linear conductor portion and the second linear conductor portion in the plan view. The conductor pattern further includes a third linear conductor portion,
The plurality of mounting electrodes further include a second mounting electrode,
The second mounting electrode is located between the first linear conductor portion and the third linear conductor portion in the plan view;
The circuit board according to claim 2, wherein the first linear conductor portion is located between the first mounting electrode and the second mounting electrode in the plan view. Circuit board,
And an antenna mounted on the circuit board,
The circuit board is
A substrate comprising first and second major surfaces opposed in the thickness direction;
A conductor pattern provided on the first main surface of the substrate;
A plurality of electrode pads provided on the second main surface of the substrate;
An electronic component provided with a plurality of mounting electrodes respectively connected to be opposed to the plurality of electrode pads;
The conductor pattern does not overlap any of the plurality of mounting electrodes in a plan view of the substrate, and has a portion overlapping the portion of the electronic component,
The wireless communication device, wherein the conductor pattern is a part of the antenna. A method of manufacturing a circuit board on which an electronic component having a plurality of mounting electrodes is mounted, comprising:
A substrate having first and second main surfaces opposed in the thickness direction, a conductor pattern provided on the first main surface, and a plurality of electrode pads provided on the second main surface Prepare
The electronic component is disposed on the substrate such that the plurality of mounting electrodes face the electrode pad,
The plurality of mounting electrodes are crimped to the electrode pad by pressing the electronic component toward the substrate.
A method of manufacturing a circuit board, wherein the conductor pattern does not overlap any of the plurality of mounting electrodes in plan view of the substrate, and has a portion overlapping the portion of the electronic component.

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