JP2006270064A - High-frequency device mounting substrate and characteristics evaluating method of high frequency device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency device mounting substrate capable of attaching/detaching a coaxial connector in a short time without applying an excessive aging on a high-frequency device which is mounted, or without damaging a central conductor of the coaxial connector and a signal electrode, while assuring rigid connection during measurement. <P>SOLUTION: In a high-frequency device mounting substrate 1, a plurality of through holes 5 penetrating a circuit board 10 are formed, being arranged along the outer periphery at the part of outer peripheral side of the circuit board 10 of the high-frequency device mounting substrate 1, on a ground electrode 4 of the high-frequency device mounting substrate 1 to which the outer peripheral conductor of the coaxial connector is connected using solder, which are connected to an internal ground conductor layer 13 by way of a conductor layer 7 coating the inner surface of the through hole 5. Since the parasitic inductance of the ground electrode 4 can be decreased while the solder continues from the inside of the through hole 5 to the outer periphery conductor of the coaxial connector, the high frequency device mounting substrate 1 is rigidly connected to the coaxial connector. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate on which a high-frequency device is mounted, and is particularly suitable for mounting a filter or a transmission / reception demultiplexing circuit (hereinafter referred to as a demultiplexer or duplexer) that is a high-frequency device used in mobile communication equipment. The present invention relates to a high frequency device mounting substrate and a method for evaluating characteristics of a high frequency device mounted on the high frequency device mounting substrate.

  In recent years, high-frequency filters such as surface acoustic wave filters used in mobile communication devices such as mobile phones are small and lightweight, have low loss in the passband, and have a large attenuation outside the passband. In addition, there is a strong demand for satisfying the characteristic that the characteristic change from the passband to the outside of the passband is steep.

  In addition, the duplexer that separates a signal in a transmission side frequency band (for example, a frequency band on a relatively low frequency side) and a signal in a reception side frequency band (for example, a frequency band on a relatively high frequency side) is also small and lightweight. The transmission filter used in the duplexer is required to have low loss in the transmission band and high attenuation in the reception band, and the reception filter must have low loss in the reception band and high attenuation in the transmission band. . Also, the duplexer is required to have good isolation characteristics from the transmission terminal to the reception terminal in order to prevent the transmission signal from leaking from the transmission terminal to the reception terminal. Further, as a duplexer, there is a demand for a smaller element in which a transmission high-frequency filter such as a low-frequency band side high-frequency filter and a reception high-frequency filter such as a high-frequency band side high-frequency filter are integrated.

  If a high-frequency device that does not satisfy the above requirements is used for communication equipment, unnecessary radio signals will be transmitted or received, and the quality of the received radio signals will deteriorate, or interference with other radio communication equipment will occur. Or other problems may occur.

  Among them, conventionally, a duplexer using a dielectric has been used. However, the dielectric duplexer could not be made small in principle in the frequency band of the current communication standard.

  Therefore, in recent years, attempts have been made to use a filter using a surface acoustic wave element for a duplexer.

  A surface acoustic wave element is usually configured by forming a plurality of excitation electrodes having comb-like electrodes on a piezoelectric substrate. The period of the electrode fingers of the comb-like electrode is substantially determined by the sound speed of the piezoelectric material of the piezoelectric substrate and the frequency band in which the surface acoustic wave element is used. For example, in the case of producing a surface acoustic wave filter used in the 800 MHz band using a lithium tantalate single crystal as a piezoelectric substrate, the period of the electrode fingers is about 4 μm, and one of the electrode fingers of the comb-like electrode Both the contact width and the distance (gap) between adjacent electrode fingers are about 1 μm.

  Conventionally, a material mainly composed of aluminum has been used as the electrode material of the comb-like electrode because of ease of handling in manufacturing and high conductivity. On the other hand, in recent years, it is necessary to devise a kind of additive element to aluminum, or to make a laminated structure of a material mainly composed of aluminum and another conductor material, so that the power durability necessary for a duplexer is thin even if it is thin. It has become possible to realize an electrode finger having

  On the other hand, surface acoustic wave elements are being reduced in size and weight. Conventionally, a surface acoustic wave device is mounted in a recess of a package body, the electrode pattern of the surface acoustic wave device and the terminal portion of the package are connected by wire bonding technology, and then the recess is hermetically sealed with a cap or the like. Thus, it is common to produce a surface acoustic wave device. On the other hand, in order to further reduce the size and weight in recent years, CSP (Chip Size Package) technology has been actively utilized, and surface acoustic wave devices have been mounted on a circuit board by flip chip mounting. It has also been proposed to reduce the space and height required for wire bonding.

  In order to evaluate the characteristics of high-frequency devices such as surface acoustic wave filters and duplexers as described above, the out-of-band attenuation characteristics and isolation characteristics of circuit boards used in mobile phones and other devices that are actually equipped with these high-frequency devices are measured. Since these must be satisfied, these high frequency devices are mounted on a mounting substrate for evaluation, and it is measured and evaluated whether or not desired characteristics are obtained. The high-frequency device mounting substrate for that purpose is required not to affect the measurement / evaluation of desired characteristics so that the measurement / evaluation cannot be performed correctly due to the mounting substrate.

  Since the measurement and evaluation must be performed accurately, the coaxial connector is usually used to connect the high-frequency device and the high-frequency device mounting board, or the high-frequency device mounting board and the coaxial cable connected to the measuring instrument. And a high-frequency device mounting substrate need to be firmly and securely connected using solder.

  FIG. 10 shows a schematic perspective view of a general high-frequency device mounting substrate, a high-frequency device connected thereto, and a coaxial connector.

  The high-frequency device mounting substrate 1 is formed by forming a necessary electric circuit with a conductor on the surface of a circuit board 10 in which a plurality of insulator layers 12 (not shown) are stacked and a ground conductor layer (not shown) is formed inside. It is.

  This electric circuit is used to connect a terminal electrode (not shown) for mounting the high-frequency device 11 to be evaluated and a coaxial connector attached to connect the cable connected to the measuring instrument and the high-frequency device mounting substrate 1. The signal electrode 3 and the ground electrode 4, and the signal line 6 that connects the terminal electrode of the high-frequency device 11 and the signal electrode 3.

  Further, by providing a through hole 17 penetrating the insulator layer of the circuit board 10 and providing a conductor layer on the inner surface of the through hole 17, the internal ground conductor layers are electrically connected to each other, and the parasitic inductance of the ground electrode 4 The grounding effect may be increased by decreasing the height.

  The coaxial connector normally includes a central conductor 14 for transmitting a signal, an outer peripheral conductor 15 surrounding and grounding the central conductor 14, and an insulating member for insulating them. The central conductor 14 is connected to the signal electrode 3 of the high-frequency device mounting substrate 1. A shape that protrudes from the insulating member so as to be connected and has a thickness that matches the width of the signal electrode 3 is used.

  In order to assemble each member as shown in FIG. 10, first, a cream solder is applied to a terminal electrode formed on the circuit board 10, and a high frequency device 11 in which an electrode is provided at a position corresponding to the terminal electrode is provided. After the high-frequency device mounting substrate 1 and the high-frequency device 11 are connected by mounting and reflowing, the signal electrode 3 and the ground electrode 4, and the central conductor 14 and the outer peripheral conductor 15 of the coaxial connector are respectively connected to the thread solder and the soldering iron. Use soldering to connect with solder.

Then, the coaxial connector is connected to the coaxial cable connected to the measuring instrument, and the characteristics of the high-frequency device 11 are measured.
JP 2002-257878 A

  By the way, the surface of the conductor portion (the central conductor 14 and the outer conductor 15) of the coaxial connector used in the example shown in FIG. Since it looks worse, it is usually protected by oxidation by gold plating. For this reason, such a component is expensive, and there has been a demand for removing it from the high-frequency device mounting substrate instead of being disposable even after one measurement and reusing it until it is damaged.

  The high-frequency device mounting substrate 1 is usually designed electrically according to the characteristics of the high-frequency device 11 to be mounted (see, for example, Patent Document 1). When it is necessary to evaluate the designed high frequency device mounting substrate 1, the high frequency device 11 is removed and the high frequency device mounting substrate 1 is reused so that the characteristic variation of the high frequency device 11 does not affect the evaluation result. There was a request to do.

  Conversely, when it is desired to evaluate the characteristic difference between the high-frequency devices 11 of different designs without being affected by the characteristic variation of the high-frequency device mounting substrate 1, it is also desired to remove the high-frequency device 11 and reuse the high-frequency device mounting substrate 1. There was a request.

  In order to implement these requirements, it is necessary to heat the high frequency device mounting substrate 1 to a temperature (200 ° C. to 300 ° C.) at which the solder melts, and to remove the high frequency device 11 with tweezers or the like. At this time, if the coaxial connector remains connected to the high frequency device mounting substrate 1, in order to remove the high frequency device 11, it is necessary to heat the entire configuration shown in FIG. 10 to a temperature at which the solder melts. There is a problem with work safety. Further, at a temperature at which the high-frequency device 11 is detached, the connection of the coaxial connector becomes very unstable, and workability is poor.

  Therefore, normally, when removing the high frequency device 11 from the high frequency device mounting substrate 1, the coaxial connector is once removed using a soldering iron, and then the solder melts the high frequency device mounting substrate 1 on a hot plate or the like. And the high frequency device 11 is removed with tweezers or the like.

  Here, if it takes a long time to remove the coaxial connector from the high-frequency device mounting substrate 1 using a soldering iron, or if the tip of the soldering iron approaches the vicinity of the high-frequency device 11, the high-frequency device 11 is heated. Will be transmitted and undesirable aging will occur.

  For example, when the high-frequency device 11 is a surface acoustic wave element, since the comb-like electrode in which many thin electrode fingers as described above are arranged with a narrow gap is used, the electrode material of the comb-like electrode by heating is used. May cause migration, and aluminum atoms move through the grain boundaries to generate protrusions (hillocks) and voids (voids) in the electrodes, which may cause short-circuit defects between comb-like electrodes of IDT electrodes. there were. In addition, even though migration does not occur, aluminum is a material with a low melting point. Therefore, recrystallization and alloying with materials that come into contact with aluminum have progressed due to heating for a long time even at the melting temperature of the solder. In some cases, the resistance increased and the power durability decreased.

  In addition, since the piezoelectric substrate has pyroelectricity, if there is a rapid temperature change due to the approach of the soldering iron, sparks may be generated between the narrow electrode fingers and the element may be destroyed. In particular, even if the soldering iron does not approach the high-frequency device 11 itself such as a surface acoustic wave element, the terminal electrode of the high-frequency device 11 is connected via the signal electrode 3 and the signal line 6 that are in direct contact with the soldering iron. The heat propagates through the signal line 6 having a high thermal conductivity because of its high conductivity, and further the heat propagated through the connection conductor in the high-frequency device 11 reaches the electrode on the piezoelectric substrate, and the temperature between the electrode and the surroundings. There was a case where a spark occurred due to the pyroelectric effect.

  In recent years, the high-frequency device 11, particularly the surface acoustic wave element, has been reduced in size and weight, and the heat capacity of the device itself is reduced accordingly, so that the heat resistance is further deteriorated. When it is necessary to remove the coaxial connector as described above, there has been a demand to complete the removal in a shorter heating time than the conventional work time.

  Thus, there has been a demand for removing the coaxial connector connected to the high frequency device mounting substrate 1 so as not to affect the high frequency device 11 mounted on the high frequency device mounting substrate 1 by heat as much as possible. However, the high-frequency device mounting board 1 and the coaxial connector are connected so that the main surface of the high-frequency device mounting board 1 and the outer peripheral conductor 15 of the coaxial connector are in contact with each other almost vertically as shown in FIG. The molten solder flows in, but there is a part where the soldering iron is difficult to reach, and it is difficult to convey the temperature of the soldering iron, so it was necessary to heat the vicinity for a long time.

  Further, in order to reduce the contact resistance by reliably connecting the outer peripheral conductor 15 of the coaxial connector and the high-frequency device mounting substrate 1, or to measure the characteristics of the high-frequency device 11 by applying a bias for a long time. In order to prevent the coaxial connector and the high-frequency device mounting substrate 1 from coming off during measurement, a ground electrode is also provided on the back surface of the high-frequency device mounting substrate 1, and this portion is also connected to the outer peripheral conductor 15 of the coaxial connector. It may be necessary to ensure a strong and reliable connection by joining with solder.

  In such a case, when removing the coaxial connector, the solder on both the main surface (front surface) and the back surface of the high-frequency device mounting substrate 1 must be removed. However, since there is an insulator layer having a low thermal conductivity between the ground electrode 4 on the main surface and the ground electrode on the back surface, the solder on both surfaces cannot be removed at the same time, and after the solder on one surface is removed If the solder on the other surface is to be removed, when the solder on the other surface is removed, the melted solder firstly passes through the gap between the coaxial connector and the contact portion of the outer peripheral portion of the high-frequency device mounting substrate 1. In some cases, it flows into the removed surface, and the ground electrode 4 on the surface and the outer peripheral conductor 15 of the coaxial connector are connected again. In particular, when solder is flowing into the gap when the coaxial connector and the high-frequency device mounting substrate 1 are first connected for measurement, the solder on the other side is gradually removed even if the solder on one side is removed. In some cases, it takes a very long time to remove the coaxial connector. In such cases, the high frequency device mounting substrate 1 is turned over and removed many times, but in that case, the connection on one side is in an unstable state with a small amount of solder connected. For this reason, a load is applied to the thin center conductor 14 of the coaxial connector, so that the center conductor 14 is broken or the signal electrode 3 of the high-frequency device mounting substrate 1 is pulled by the center conductor 14 and peeled off. was there.

  Furthermore, not only when performing measurement / evaluation as described above, but also when mounting a high-frequency device mounting board in a communication device such as a base station or a terminal and actually operating it, the high-frequency device mounting board and other circuit components It is required that the coaxial connector for connecting the connector and the high-frequency device mounting substrate be firmly connected using solder. If the connection is weak, the certainty of conductivity is lost, and the reliability of the operation of the high-frequency device is lowered.

  The present invention has been devised in view of the above-described problems in the prior art, and its purpose is to give excessive aging to the mounted high-frequency device or to provide signal electrodes and coaxial connectors on the high-frequency device mounting substrate. It is an object of the present invention to provide a high-frequency device mounting substrate that can remove a coaxial connector in a short time without damaging the central conductor of the semiconductor device and that can ensure a strong connection during measurement.

  Another object of the present invention is to provide a high-frequency device mounting substrate that can ensure a strong connection with a coaxial connector and that can be easily removed when removed.

  Still another object of the present invention is to provide a method for evaluating the characteristics of a high-frequency device that can evaluate the characteristics of the high-frequency device mounted on the high-frequency device mounting substrate with high reliability.

  The high-frequency device mounting substrate of the present invention includes a circuit board having a conductor layer on the back surface or inside of an insulator layer, a terminal electrode mounted on the surface of the circuit board for mounting a high-frequency device, and the circuit board. A signal line installed on the surface and connected to the terminal electrode, a signal electrode arranged at a peripheral portion of the surface of the circuit board, connected to the signal line and connected to a central conductor of the coaxial connector, and a surface of the circuit board A ground electrode for connecting the outer peripheral conductor of the coaxial connector using solder, penetrating the circuit board in a region to which the solder adheres and having a conductor layer deposited on the inner surface And a ground electrode having a through hole formed therein.

  The high-frequency device mounting substrate of the present invention has the above-described configuration, and the circuit substrate is a laminated substrate in which a plurality of insulator layers are laminated, and an internal conductor layer is formed therein, and is formed on the inner surface of the through hole. The conductor layer is connected to the inner conductor layer.

  The high-frequency device mounting board of the present invention has the above-described configuration, wherein the circuit board is formed with a second ground electrode at a portion corresponding to the ground electrode on the back surface, and the second ground electrode is formed of the through hole. It is connected to the ground electrode on the surface of the circuit board through the conductor layer formed on the inner surface.

  The high-frequency device mounting substrate of the present invention has the above-described configuration, in which a plurality of the through holes are arranged in a portion of the ground electrode along the outer periphery of the circuit board.

  The high-frequency device mounting substrate of the present invention has the above-described configuration, wherein the through hole is disposed at a portion of the ground electrode opposite to the signal line from the outer periphery to the center portion of the circuit substrate. .

  In the high-frequency device mounting board of the present invention, a surface ground conductor layer formed along the signal line on the surface of the circuit board is connected to the ground electrode.

  The method for evaluating the characteristics of a high-frequency device according to the present invention is a method for evaluating the characteristics of a high-frequency device mounted on a high-frequency device mounting substrate, the step of mounting the high-frequency device on the high-frequency device mounting substrate according to the present invention having the above-described configuration, And a coaxial connector connecting step of connecting a coaxial connector to the high frequency device mounting substrate using solder, and a characteristic inspection step of performing a characteristic inspection of the high frequency device mounted on the high frequency device mounting substrate.

  According to the high-frequency device mounting substrate of the present invention, a circuit board having a conductor layer on the back surface or inside of the insulator layer, a terminal electrode for mounting a high-frequency device installed on the surface of the circuit board, and the circuit A signal line installed on the surface of the substrate and connected to the terminal electrode; a signal electrode disposed in a peripheral portion of the surface of the circuit board; connected to the signal line and connected to a central conductor of a coaxial connector; and the circuit board And a ground electrode for connecting the outer peripheral conductor of the coaxial connector using solder, and the ground electrode penetrates the circuit board in a region to which the solder adheres. A through hole is formed, and a conductor layer is deposited on the inner surface of the through hole.

  According to this high-frequency device mounting substrate, when the outer peripheral conductor of the coaxial connector is attached using solder, the solder flows into the through hole formed in the ground electrode. As a result, the outer peripheral conductor of the coaxial connector can be firmly joined to the ground electrode of the circuit board.

  Further, the internal ground conductor layer is connected to the ground potential of the measuring instrument in a state where the parasitic inductance is smaller than when the through hole 17 is provided in the portion closer to the high frequency device 11 of the circuit board 10 as shown in FIG. Therefore, the characteristics of the high frequency device can be measured more accurately.

  The circuit board is a laminated board in which a plurality of insulator layers are laminated, an internal conductor layer is formed therein, and the conductor layer formed on the inner surface of the through hole is connected to the internal conductor layer. May be.

  Further, a second ground electrode is formed at a portion corresponding to the ground electrode on the back surface of the circuit board, and the second ground electrode is interposed through the conductor layer formed on the inner surface of the through hole. It is preferable to be connected to the ground electrode.

  In this structure, as described above, when the second ground electrode on the back surface of the circuit board is also connected to the outer peripheral conductor of the coaxial connector, the solder existing on the upper surface of the ground electrode on the front surface and the second ground electrode on the back surface, respectively. Since the solder in the through hole penetrating between the ground electrode and the ground electrode can be continuously connected to the outer peripheral conductor of the coaxial connector, the coaxial connector is more firmly connected. At the same time, when soldering, the heat of the soldering iron quickly passes from the solder existing on one surface (for example, the front surface) to the solder existing on the other surface (for example, the back surface) through the solder in the through hole. Since the solder on both sides can be melted at the same time through the through-holes, the amount of solder on both sides is equalized through the through-holes. Therefore, the load applied to the central conductor of the coaxial connector and the signal electrode of the high-frequency device mounting board Can be reduced.

  Similarly, when removing the coaxial connector, the solder on both sides can be melted at the same time, so that the removal operation can be completed easily in a short time without causing various problems as in the prior art. Therefore, the mounted high frequency device can be removed without deteriorating its characteristics. Further, they can be reused without damaging the coaxial connector or the high-frequency device mounting substrate by heat.

  A plurality of through-holes for connecting the ground electrode and the ground conductor layer through the conductor layer are disposed along the outer periphery of the circuit board in a portion on the outer peripheral side of the circuit board in a region where the solder of the ground electrode adheres. In this case, the electrical path of the outer peripheral conductor of the coaxial connector connected by solder, the conductor layer in the through-hole, and the inner-layer conductor can be minimized, so that the parasitic inductance caused by the conductor layer in the through-hole is minimized. Can be small. In addition, since solder can be continuously present from the through hole of the ground electrode to the outer peripheral conductor of the coaxial connector, the high-frequency device mounting board and the coaxial connector can be connected more firmly and coaxially during measurement. The probability that the connector is detached from the high-frequency device mounting board can be extremely reduced.

  Further, when the through hole is further arranged from the outer periphery of the circuit board toward the central portion at a portion of the ground electrode opposite to the signal line, the following effects are obtained.

  In conventional high-frequency device mounting boards, if the amount of solder is increased in order to achieve a strong joint when connecting the coaxial connector, the signal electrode and the ground electrode that are placed close to each other may be short-circuited via the solder. According to the high-frequency device mounting substrate of the present invention, when the through hole is further arranged from the outer periphery of the circuit board toward the central portion at a portion opposite to the signal line of the ground electrode, When soldering, the excessive solder with respect to the ground electrode on the front surface flows to the second ground electrode on the back surface through the further disposed through hole, so that the shape of the solder is slightly opposite to the signal line of the ground electrode. Become. For this reason, it is possible to make it difficult for the solder to be used to flow to the signal electrode side, so that it is possible to effectively prevent the signal electrode and the ground electrode from being short-circuited via the solder.

  Furthermore, when a surface ground conductor layer formed along the signal line is connected to the surface of the circuit board to the ground electrode, the surface ground conductor layer is grounded with the smallest parasitic inductance. Since it can be connected to an electrode, the potential of the grounded electrode among the signal terminals of the high-frequency device can be made closer to the ground potential of the measuring instrument.

  The method for evaluating characteristics of a high-frequency device according to the present invention includes a step of mounting a high-frequency device on a high-frequency device mounting board on which the coaxial connector can be attached, and connecting the coaxial connector to the high-frequency device mounting board using solder. And a characteristic inspection step of performing a characteristic inspection of the high-frequency device mounted on the high-frequency device mounting substrate. According to this method, the coaxial connector can be securely connected to the high-frequency device mounting substrate to evaluate the characteristics of the high-frequency device, and can be easily removed when removing the high-frequency device.

  The effect of attaching the coaxial connector in the high-frequency device mounting board of the present invention as described above to the high-frequency device mounting board is that the coaxial connector and the high-frequency device mounting board are temporarily connected and the coaxial connector is removed after measurement. Of course, it is also effective when connecting a so-called motherboard (main board) that requires a permanent connection and a connector that connects this motherboard to an external circuit, and is within the technical scope of the present invention. . The effect of removing the coaxial connector from the high-frequency device mounting board is also effective when repair is required in the connection between the motherboard and the connector that requires permanent connection.

  Below, the example of embodiment of the high frequency device mounting substrate of this invention is demonstrated in detail based on drawing shown typically. In the drawings described below, the same parts and the same parts are denoted by the same reference numerals.

<Example 1 of embodiment>
FIG. 1 is a top view showing an example of an embodiment of a high-frequency device mounting substrate of the present invention. FIG. 2 is a cross-sectional view of the main part taken along the line AA ′ of FIG.

  The high-frequency device mounting substrate 1 is a terminal on which a high-frequency device is mounted at the center of the surface (upper surface) of the circuit board 10 having a structure in which insulator layers 12, 19 and 21 and ground conductor layers 13 and 20 are laminated. An electrode 2 is provided. An electronic component 30 such as a resistor, a capacitor, or an integrated circuit is mounted on the surface of the circuit board 10.

  A signal electrode 3 to which a central conductor (not shown) of the coaxial connector is connected and a ground electrode 4 to which an outer peripheral conductor (not shown) of the coaxial connector is connected using solder at the periphery of the surface of the circuit board 10. Is formed.

  The terminal electrode 2 and the signal electrode 3 are connected by signal lines that extend radially from the center of the circuit board 10.

  Here, a through hole 5 is formed along the outer periphery of the circuit board 10 at a portion of the ground electrode 4 on the outer periphery side of the circuit board 10. As shown in FIG. 2, a conductor layer 7 is attached to the inner surface of the through hole 5. The conductor layer 7 electrically connects the ground electrode 4 and the ground conductor layers 13 and 20.

  A predetermined terminal to be grounded among the terminal electrodes 2 is connected by forming a via conductor (not shown) filled with a conductor in the ground conductor layer 13 immediately below the terminal electrode 2.

  When measuring the characteristics of a high-frequency device (not shown) using the high-frequency device mounting substrate 1 of the present invention, first, cream solder or the like is applied to the terminal electrode 2 and this corresponds to the high-frequency device. A terminal (not shown) is brought into contact and heated above the melting temperature of the cream solder. As a result, the high frequency device is mounted on the high frequency device mounting substrate 1.

  Next, a coaxial connector (not shown) is joined to the signal electrode 3 and the outer peripheral conductor of the coaxial connector to the ground electrode 4 using a thread solder and a soldering iron.

  At that time, due to the presence of the through hole 5, the melted solder flows from the ground electrode 4 into the through hole 5 and enters the through hole 25. In this way, solder is continuously formed from the inside of the through hole 5 to the outer peripheral conductor 15 of the coaxial connector.

  For this reason, since the strong connection between the high frequency device mounting substrate 1 and the coaxial connector can be ensured, even if a physical load is applied from a cable or the like connected during measurement, the central conductor of the coaxial connector and the signal electrode 3 The probability of deviating can be made extremely small.

  Further, the outer peripheral conductor of the coaxial connector and the ground conductor layer 13 are connected to each other at a position closest to the ground electrode of the measuring instrument through the ground electrode 4 and the conductor layer 7 in the through hole 5 in the high-frequency device mounting substrate 1. Therefore, the parasitic inductance caused by the physical distance between the ground electrode of the measuring instrument and the ground conductor layer 13 can be reduced. Therefore, the characteristics of the high frequency device can be measured more accurately.

<Example 2 of embodiment>
Next, still another example of the embodiment of the present invention will be described. In this example, the top view of the high-frequency device mounting substrate 1 is the same as that in FIG. 1, but the second ground electrode 8 is provided in a portion corresponding to the ground electrode 4 on the back surface of the circuit board 10.

  FIG. 3 shows a top view of the back surface of the high-frequency device mounting substrate 1 of this example. Further, FIG. 4 shows a cross-sectional view of the main part of this example cut along the line AA ′ of FIG. 4 is different from FIG. 2 in that the second ground electrode 8 is provided on the back surface of the high-frequency device mounting substrate 1 in FIG.

  The second ground electrode 8 on the back surface is electrically connected to the ground electrode 4 on the main surface (front surface) and the ground conductor layer 13 inside through the conductor layer 7 on the inner surface of the through hole 5.

  Further, FIG. 5 shows a cross-sectional view of the main part taken along the line BB ′ of FIG. 1 when the high-frequency device mounting substrate 1 of this example and the coaxial connector are connected by solder.

  As shown in FIG. 5, the solder 16 is continuously present from the back surface side of the high-frequency device mounting substrate 1 through the through hole 5 to the outer peripheral conductor on the main surface side with respect to the outer peripheral conductor (not shown) of the coaxial connector. Therefore, the ground electrode 4 of the high-frequency device mounting substrate 1 and the outer peripheral conductor of the coaxial connector can be connected more firmly.

  Further, when the ground electrode 4 and the outer peripheral conductor of the coaxial connector are connected by the solder 16, the heat of the soldering iron is transferred from the solder 16 existing on one surface to the other surface via the solder 16 in the through hole 5. Therefore, the solder 16 on both sides can be melted at the same time. As a result, the amount of solder on both sides is equalized, so that the stress and load applied to the central conductor 14 of the coaxial connector and the signal electrode 3 of the high-frequency device mounting substrate 1 can be reduced.

  Also, when removing the coaxial connector, the solder 16 on both sides can be melted at the same time, so that the removal operation can be completed easily in a short time. Therefore, the mounted high frequency device can be removed without deteriorating its characteristics. Moreover, these can be reused without damaging the coaxial connector or the high-frequency device mounting substrate 1.

  Further, the outer peripheral conductor of the coaxial connector is grounded at a position closest to the ground electrode of the measuring instrument via the ground electrode 4, the second ground electrode 8 and the conductor layer 7 in the through hole 5 in the high-frequency device mounting substrate 1. Since the conductor layer 13 can be connected, the parasitic inductance due to the physical distance between the ground electrode of the measuring instrument and the ground conductor layer 13 can be reduced. Therefore, the characteristics of the high-frequency device can be measured more accurately. This can be done in the same manner as in Example 1 of the embodiment.

<Example 3 of embodiment>
Next, still another example of the embodiment of the present invention will be described.

  6A and 6B are top views (plan views) of the main surface of the high-frequency device mounting substrate 1 of this example. In this example of FIG. 6A, the through hole 5 is formed in the outer peripheral side portion of the circuit board 10 of the ground electrode 4 on the surface of the high-frequency device mounting substrate 1, and the side opposite to the signal line 6 of the ground electrode 4. A through hole 5 ′ is further arranged at the part from the outer periphery of the circuit board 10 toward the center. In this example of FIG. 6B, the through hole 5 is not formed, and instead, the through hole 5 is formed on the opposite side of the ground electrode 4 from the signal line 6 from the outer periphery of the circuit board 10 toward the center. ′ Was placed.

  In addition, when the coaxial connector is connected to the high-frequency device mounting substrate 1 of this example with a large amount of solder 16 in order to make a strong connection, it is necessary to cut along the CC 'line in FIGS. 6 (a) and 6 (b). A partial cross-sectional view is shown in FIG.

  Further, FIG. 8 shows a cross-sectional view of the main part similar to FIG. 7 when the through hole 5 ′ is not provided as a comparative example.

  When the through hole 5 ′ is not provided for the ground electrode 4, the distribution of the solder 16 existing on the upper surface of the ground electrode 4 and the upper surface of the signal electrode 3 is represented by the surface tension of the solder 16 as shown in FIG. Therefore, there is a case where a short circuit occurs depending on the amount of solder.

  On the other hand, in the case of this example, as the distribution of the solder 16 is as shown in FIG. 7, the solder 16 flows into the through hole 5 ′, so that the solder 16 existing on the upper surface of the ground electrode 4 is slightly removed from the signal electrode 3. The signal electrode 3 and the ground electrode 4 can be made difficult to be short-circuited via the solder 16.

  In addition, although the case where there is no second ground electrode 8 on the back surface is shown here, the second ground electrode 8 may be provided on the back surface of the high-frequency device mounting substrate 1 as in the examples shown in FIGS. Absent.

<Example 4 of embodiment>
Next, still another example of the embodiment of the present invention will be described.

  FIG. 9 shows an upper surface of the main surface of the high-frequency device mounting substrate 1 of this example in which the surface ground conductor layer 9 is provided along the signal line 6 on the main surface (front surface) of the circuit board 10 and is connected to the ground electrode 4. It is a figure (plan view).

  By adopting such a configuration, the surface ground conductor layer 9 can be connected to the ground electrode of the measuring instrument with the smallest parasitic inductance, so that the potential of the grounded terminal among the signal terminals of the high frequency device can be Thus, it can be brought close to the ground potential of the measuring instrument with a smaller parasitic inductance.

  The high-frequency device mounting substrate 1 of the present invention can be applied to communication equipment. That is, the high-frequency device mounting substrate 1 of the present invention can be used in a communication device including one or both of a receiving circuit and a transmitting circuit. The transmission circuit is, for example, a circuit that places a transmission signal on a carrier frequency with a mixer, attenuates an unnecessary signal with a bandpass filter, then amplifies the transmission signal with a power amplifier, and transmits it from an antenna through a duplexer. is there. The receiving circuit receives the received signal with an antenna, amplifies the received signal that has passed through the duplexer with a low noise amplifier, then attenuates an unnecessary signal with a bandpass filter, and separates the signal from the carrier frequency with a mixer. A circuit for extracting a signal. By mounting the duplexer or band-pass filter on the high-frequency device mounting substrate 1 of the present invention and incorporating the duplexer or the band-pass filter into the communication device, a communication device having excellent characteristics on which the high-frequency device mounting substrate 1 of the present invention is mounted can be realized.

  Next, a method for evaluating a high frequency device using the high frequency device mounting substrate 1 will be described.

  The high-frequency device mounting substrate 1 is used for the purpose of performing non-defective product determination in the characteristic inspection process of the high-frequency device mass production process and for the purpose of evaluating the characteristics of the developed product.

  Specifically, in the case of a duplexer using a piezoelectric filter as a high-frequency device, a large number of piezoelectric filters are collectively formed on a wafer made of a piezoelectric material, and then the piezoelectric filter is cut into individual pieces. Then, each piezoelectric filter is flip-chip mounted on a predetermined circuit board in a flip-chip manner to obtain a duplexer, and the obtained duplexer is mounted on the high-frequency device mounting board 1 to determine non-defective products. Since the duplexer cannot be bonded to the high frequency device mounting substrate 1 with solder in the characteristic inspection process for determining the non-defective product, the connection between the duplexer and the high frequency device mounting substrate 1 is a terminal electrode on the high frequency device mounting substrate 1. This is done via a contact pin or the like. In this case, in order to stably measure the characteristics, the high frequency device mounting substrate 1 is fixed on a base such as brass or aluminum together with a jig for fixing the contact pin and a guide for fixing the mounting position of the duplexer, and the upper part of the duplexer. By pressing with a more constant pressure, the connection with the contact pin is made constant.

  In this state, as described above, the coaxial cable is connected to the signal electrode 23 and the ground electrode 24 of the high-frequency device mounting substrate 1 by soldering, and the characteristics of the high-frequency device are evaluated.

  According to the above-described method for evaluating the characteristics of a high-frequency device of the present invention, the coaxial connector can be securely connected to the high-frequency device mounting substrate 1 to evaluate the characteristics of the high-frequency device, and even when the high-frequency device is removed, Can be removed.

<First embodiment>
Next, a first embodiment in which the high-frequency device mounting substrate of the present invention is more concrete will be described.
The positions and shapes of the signal line 6, the signal electrode 3, and the ground electrode 4 of the high-frequency device mounting substrate 1 are the same as the example shown in FIG. That is, the signal line 6 extends radially from the terminal electrode 2, and the structure of the region D to which the coaxial connector is connected is as shown in FIG. The number and positions of the through holes 5 are as shown in FIG. FIG. 11 is an enlarged view of a region D indicated by a broken line in FIG. As shown in FIG. 9, there are three portions to which the coaxial connector is connected, including the region D, and all of them have the shape shown in FIG.

  Further, FIG. 12 shows an enlarged view of the back surface of the portion corresponding to FIG. 11 of the circuit board 10. The second ground electrode 8 at a portion corresponding to the two ground electrodes 4 on the surface was formed as a continuous one. In FIG. 12, reference numeral 9 ′ denotes a back surface ground conductor layer formed on the back surface of the circuit board 10. In this embodiment, three portions for connecting the coaxial connector to the high-frequency device mounting substrate 1 are provided as shown in FIG. 9, but all of them are formed in the shape shown in FIG. Moreover, the principal part sectional view is the same as FIG.

  As a material of the insulator layers 12, 19, and 21 of the circuit board 10, FR-4 (glass epoxy resin), ground conductor layers 13 and 20, the ground electrode 4, the second ground electrode 8, and the back surface ground conductor layer are used. Copper was used as the material for 9 '.

The thickness of the insulator layer 12 and the insulator layer 21 is 0.1 mm, respectively, and the thickness of the insulator layer 19 is 1 mm. Moreover, the thickness of the ground conductor layer 13 and the ground conductor layer 20 is 0.035 mm, respectively. The thicknesses of the ground electrode 4 and the second ground electrode 8 are each 0.06 mm. The width of the signal line 6 on the main surface of the circuit board 10 is 0.13 mm, the width w ₁ of the signal electrode 3 to which the central conductor 14 of the coaxial connector is connected is 0.6 mm, the lateral width w ₂ of the ground electrode 4 is 5 mm, and the signal The gap w ₃ between the electrode 3 and the ground electrode 4 was 0.85 mm.

The characteristic impedance of the signal line 6 was designed to be 50Ω. Vertical width _{w 4} of the ground electrode 4 was set to 3mm. Further, the lateral width w ₅ of the second ground electrode 8 on the back surface of the circuit board 10 was 13 mm, and the longitudinal width w ₆ was 3 mm. Further, a through hole 5 having a radius of 0.3 mm that penetrates the circuit board 10 and the second ground electrode 8 on the back surface of the circuit board 10 is formed in the ground electrode 4 by 0.6 mm from the inside of the ground electrode 4. 6 pieces were provided at intervals of 0.8 mm from a position of 0.3 mm from the outer peripheral portion (the outer peripheral side of the circuit board 10). Each through-hole 5 is provided with a conductor layer 7 made of copper on the inner surface, and the surface ground conductor layer 9 connected to the ground electrode 4 and the surface ground conductor layer 9 ′ connected to the second ground electrode 8 are grounded. The potential was stabilized.

  Further, as a comparative example, a conventional high-frequency device mounting substrate having the same design as this example except that the through hole 5 is not provided was manufactured.

  For the examples and comparative examples of the present invention thus produced, each mounted with a high frequency device, and after attaching a coaxial connector, after measuring the high frequency characteristics via the signal line 6, and then removing the coaxial connector, The high frequency characteristics were measured again.

  The measurement at this time was performed by bringing a high-frequency probe (product name: Picoprobe 40A-GS-600-DP) directly into contact with the terminal electrode of the high-frequency device.

  In addition, as a high frequency device, the size of the surface connected to the terminal electrode 2 is 2.5 mm × 2.0 mm, and a 800 MHz using a small high frequency filter (surface acoustic wave filter) having a height of 0.6 mm. A band duplexer was used.

  First, for both the example and the comparative example, cream solder was applied to the terminal electrode 2 and this high frequency device was mounted. And the cream solder was melted using a hot plate, and the terminal of the high frequency device and the terminal electrode 2 were connected.

  Next, a coaxial connector was attached. In both the example and the comparative example, thread solder (Sn—Cu—Ag: melting point 217 ° C.) is melted to the signal electrode 3, the ground electrode 4, and the second ground electrode 8 using a soldering iron, and high frequency A coaxial connector was attached to the device mounting board 1.

  In the case where the comparative example is used, even if heat is applied to the thread solder for the same time, the amount of melting is not constant, and the solder between the ground electrode 4 and the second ground electrode 8 cannot directly flow. It was very difficult to make the amount of solder between 4 and the ground electrode 8 uniform.

  On the other hand, in the embodiment, when the solder 16 of the signal electrode 3 and the ground electrode 4 is melted by using a soldering iron, the solder 16 on the second ground electrode 8 is also heated through the through hole 5. Therefore, the solder 16 on the second ground electrode 8 can be melted at the same time, and the melted solder 16 flows to each other through the through hole 5, so that the ground electrode 4 and the second ground electrode The deviation of the solder amount between 8 and 8 could be eliminated.

  Next, the coaxial connector connected to the high frequency device mounting substrate 1 and the measuring device were connected by a cable, and the high frequency characteristics of the high frequency device were measured.

  During this measurement, in the comparative example, the coaxial connector was disconnected due to the force applied by the cable connecting the coaxial connector and the measuring device, but in the example, as shown in FIG. On the other hand, the solder 16 can be continuously present from the second ground electrode 8 side on the back surface of the high-frequency device mounting substrate 1 through the through hole 5 to the outer peripheral conductor on the ground electrode 4 side of the main surface. The high frequency device mounting substrate 1 and the coaxial connector could be connected to each other, and the coaxial connector was never detached.

  Next, the coaxial connector was removed from the high frequency device mounting substrate 1.

  In the case of the comparative example, in order to remove the coaxial connector, first, the solder of the second ground electrode 8 is removed using a solder sucker (manufacturer: manufactured by Hakko Co., Ltd., product name: solder removal station 24V474). And the high-frequency device mounting substrate 1 are held only by the solder on the signal electrode 3 and the ground electrode 4, the solder between the signal electrode 3 and the ground electrode 4 is melted, and the coaxial connector is mounted on the high-frequency device. It was removed from the substrate 1.

  On the other hand, in the case of the embodiment, when the solder 16 of the signal electrode 3 and the ground electrode 4 is melted by using a soldering iron, the solder 16 on the second ground electrode 8 through the through hole 5. Further, since heat is conducted, the solder 16 on the second ground electrode 8 can be melted at the same time. For this reason, the coaxial connector was able to be removed very easily in a short time as compared with the comparative example.

  In this way, the embodiment does not require the use of a solder sucker as compared with the comparative example, and by simply applying heat to the solder 16 on one side using a soldering iron, the solder 16 on the other side is melted to form a coaxial connector. And the time during which heat is applied to the high-frequency device mounting substrate 1 and the high-frequency device can be extremely shortened.

  Next, the high frequency device was removed. Both the example and the comparative example were placed on a hot plate and heated to melt the cream solder, and the high frequency device was removed using tweezers.

  Thereafter, the high frequency characteristics of the removed high frequency device were measured. As a result, when the high-frequency device mounting substrate 1 of the example of the present invention was used, there was no high-frequency device whose characteristics deteriorated before and after the above series of operations, but when the high-frequency device mounting substrate of the comparative example was used. High-frequency devices with deteriorated high-frequency characteristics were generated by heat applied during installation and removal of the coaxial connector.

<Second embodiment>
Next, a second embodiment in which the high-frequency device mounting substrate of the present invention is embodied more specifically will be described. Although the top view of the main surface of the high-frequency device mounting substrate 1 is the same as that of the first embodiment, the end of the ground electrode 4 opposite to the signal electrode 3 is shown in FIG. 13 as an enlarged view similar to FIG. The difference is that two through-holes 5 ′ having the same dimensions as the through-holes 5 are installed from the outer peripheral part of the circuit board 10 toward the center part from the through-holes 5 </ b> A located in the part. The sectional view is the same as that of the first embodiment.

  In the first embodiment, as shown in FIG. 8, the distribution of the solder 16 existing on the upper surface of the ground electrode 4 and the upper surface of the signal electrode 3 is close due to the surface tension of the solder 16. Sometimes short-circuited through these solders 16.

  By providing the through hole 5 'in the ground electrode 4 as in this embodiment, the solder 16 flows into the through hole 5' as shown in FIG. 7, so that the solder 16 existing above the ground electrode 4 is used as the signal electrode. Therefore, the signal electrode 3 and the ground electrode 4 were not short-circuited through the solder 16.

  In addition, this invention is not limited to the example of the above embodiment, A various change may be added in the range which does not deviate from the summary of this invention. The scope of the present invention also extends to any combination of the configurations of the claims.

  For example, the material of the insulator layer of the circuit board is not limited to the materials given in the examples, and for example, organic materials such as tetrafluoroethylene and BT resin, ceramics such as alumina, or alumina as a main component Inorganic materials such as glass ceramics may be used.

  Further, the number of laminated layers of the insulator layer, the conductor layer covering the back surface of the insulator layer, and the ground conductor layer may be arbitrary. In the above example, the ground conductor layer 20 is further provided on the back side in addition to the ground conductor layer 13, but the ground conductor layer 20 may be omitted.

  Moreover, although the shape of the through-hole 5 is circular in FIG. 1 and the like, the shape may be arbitrary. In addition, the position is provided in a region slightly entering the central portion side from the outer periphery of the circuit board 10 toward the central portion. The inner surface of the circuit board 10 is formed by opening a through hole in the length direction. The conductor layer 7 may be attached to the ground electrode 4 as a so-called castellation conductor, and the ground electrode 4, the ground conductor layers 13, 20 and the second ground electrode 8 may be connected via the outer peripheral side surface of the circuit board 10. .

  Further, the characteristic impedance of the signal line 6 is not limited to 50Ω, and may be set according to the characteristic impedance of the system using the high frequency device.

  In the above description, the signal lines 6 are arranged on the surface of the high-frequency device mounting substrate 1, but as shown in FIG. 14, some of the signal lines are arranged inside the insulator layer. It does not matter. In this case, by providing the signal lines in different layers, the signal lines do not face each other in the thickness direction, so that it is possible to further improve the isolation characteristics between the signal lines. The influence on the characteristics can be further reduced, or the characteristics can be exhibited better.

  In the figure used for explanation, the case where there are three terminals (a set of the signal electrode 3 and the ground electrode 4) to which the high-frequency device mounting substrate 1 and the coaxial connector are connected is shown. It may be arbitrary according to the number of terminals.

  Moreover, you may protect the part which does not need to contact solder among the surfaces of the high frequency device mounting substrate 1 with a soldering resist etc. By doing so, it is possible to make the solder exist only in the portion where the solder is desired to be in contact, and it is possible to prevent the conductors such as the signal line 6 from being short-circuited through the extra solder.

  Furthermore, high frequency devices are not limited to piezoelectric filters and duplexers, but are applicable to high frequency signal processing applications such as mobile communication devices, wireless LAN, ETC, and main boards (motherboards). Is possible.

It is a top view which shows an example of embodiment of the high frequency device mounting board | substrate of this invention. It is principal part sectional drawing cut | disconnected by the AA 'line of the example shown in FIG. It is a back view which shows the other example of embodiment of the high frequency device mounting board | substrate of this invention. FIG. 4 is a cross-sectional view of a main part taken along the line AA ′ of FIG. 1 in the example shown in FIG. 3. FIG. 4 is a cross-sectional view of an essential part taken along line BB ′ of FIG. 1 when the example shown in FIG. 3 is connected to a coaxial connector by solder. (A), (b) is the top view of the main surface which shows the further another example of embodiment of the high frequency device mounting board | substrate of this invention. It is principal part sectional drawing cut | disconnected by CC 'line of the example shown in FIG. It is principal part sectional drawing similar to FIG. 7 of the high frequency device mounting board | substrate of a comparative example. It is a top view which shows the further another example of embodiment of the high frequency device mounting board | substrate of this invention. It is a schematic perspective view of the conventional general high frequency device mounting substrate, the high frequency device connected to it, and a coaxial connector. FIG. 10 is an enlarged view of a region D in FIG. 9. It is an enlarged view of the back surface of the area | region D in the example of the high frequency device mounting substrate of this invention. It is an enlarged view of the area | region D in the example of the high frequency device mounting board | substrate of this invention. It is sectional drawing which shows the high frequency device mounting substrate of this invention which formed the signal wire | line in the circuit board.

Explanation of symbols

1: High-frequency device mounting substrate 2: Terminal electrode 3: Signal electrode 4: Ground electrode 5, 5 ′, 5A: Through hole 6: Signal line 7: Conductor layer 8: Second ground electrode 9: Surface ground conductor layer 9 ′ : Back surface ground conductor layer 10: Circuit board 11: High frequency device 12, 19, 21: Insulator layer 13, 20: Ground conductor layer 14: Center conductor of coaxial connector 15: Outer conductor of coaxial connector 16: Solder 17: Through hole 23: Signal electrode 24: Ground electrode 25: Through hole 30: Electronic component

Claims (8)

A circuit board having a conductor layer on the back surface or inside of the insulator layer;
Terminal electrodes installed on the surface of the circuit board for mounting a high-frequency device;
A signal line installed on the surface of the circuit board and connected to the terminal electrode;
A signal electrode disposed in a peripheral portion of the surface of the circuit board, connected to the signal line, and connected to a central conductor of a coaxial connector;
A ground electrode disposed on a peripheral portion of the surface of the circuit board for connecting the outer peripheral conductor of the coaxial connector using solder, penetrating the circuit board in an area where the solder adheres and on the inner surface A high-frequency device mounting substrate comprising: a ground electrode having a through hole formed with a conductor layer deposited thereon. The circuit board is a laminated board in which a plurality of insulator layers are laminated, and an internal conductor layer is formed therein,
The high frequency device mounting substrate according to claim 1, wherein a conductor layer formed on an inner surface of the through hole is connected to the inner conductor layer. The circuit board has a second ground electrode formed in a portion corresponding to the ground electrode on the back surface thereof,
3. The high-frequency device according to claim 1, wherein the second ground electrode is connected to the ground electrode on the surface of the circuit board through the conductor layer formed on the inner surface of the through hole. Mounting board.   4. The high-frequency device mounting substrate according to claim 1, wherein a plurality of the through holes are arranged in a portion of the ground electrode along a periphery of the circuit board.   5. The high-frequency device mounting substrate according to claim 4, wherein the through-hole is further disposed from a periphery of the circuit substrate toward a central portion at a portion of the ground electrode opposite to the signal line.   The said through-hole is arrange | positioned from the outer periphery of the said circuit board toward the center part in the site | part on the opposite side to the said signal wire | line of the said ground electrode. High frequency device mounting board.   The high-frequency device mounting substrate according to claim 1, wherein a surface ground conductor layer formed along the signal line is connected to the surface of the circuit substrate to the ground electrode. A method for evaluating characteristics of a high-frequency device mounted on a high-frequency device mounting substrate,
A step of mounting the high-frequency device on the high-frequency device mounting substrate according to any one of claims 1 to 7,
A coaxial connector connecting step of connecting a coaxial connector to the high-frequency device mounting substrate using solder;
A characteristic evaluation method for a high frequency device, comprising: a characteristic inspection step for performing a characteristic inspection of the high frequency device mounted on the high frequency device mounting substrate.

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