JP2008047647A - High frequency module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency module which can suppress a residual inductance generated by variations in the mounted height of a high frequency component even when the high frequency component is made compact. <P>SOLUTION: A high frequency module 50 comprises (a) a circuit board 52 having a signal electrode pad formed thereon, (b) connection conductors 54a to 54f formed on the signal electrode pad to be extruded from the circuit board 52, and (c) a high frequency component 56 having terminal pads 58a to 58f (58a and 58b not shown) connected to the connection conductors 54a to 54f to be mounted on the circuit board 52. The module also includes (i) a grounding electrode pad formed around a high frequency component mount region 56a for the high frequency component 56 of the circuit board 52 to be mounted thereon, and (ii) grounding conductors 55a to 55f formed on the grounding electrode pad to be extruded from the circuit board 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-frequency module, and more particularly to a high-frequency module configured by mounting high-frequency components on a circuit board.

  For example, as schematically shown in an exploded perspective view of FIG. 1A and a plan view of FIG. 1B, a chip component of a SAW (surface acoustic wave) duplexer is mounted on the circuit board 12 as the high-frequency component 16. A high frequency module 10 is provided. On the upper surface 12a of the circuit board 12, connection conductors 14a to 14f such as solder are formed on electrode pads (not shown) in the high frequency component mounting region 16a on which the high frequency component 16 is mounted, and the connection conductors 14a to 14f are formed. Are connected to terminal pads 18a to 18f (18a and 18b are not shown) of the high-frequency component 16, respectively. The connection conductors 14a, 14c, and 14e are electrically connected to a reception terminal, a transmission terminal, and an antenna terminal (not shown) formed on the lower surface 12b of the circuit board 12 through a lead electrode 15 formed inside the circuit board 12. It is connected. The hatched connection conductors 14b, 14d, and 14f are electrically connected to a ground terminal (not shown) formed on the lower surface 12b of the circuit board 12 via a lead electrode (not shown).

Patent Document 1 discloses a high-frequency component 1 shown in FIGS. 9 to 11. As shown in the cross-sectional view of FIG. 11, the high-frequency component 1 includes electrodes 8 a to 8 e that constitute capacitors and inductors, through-holes 7, and the like in the multilayer body 2, and terminal pads 4 on the side surface and the back surface of the multilayer body 2. Is formed. A chip component 9 such as a chip capacitor or a diode is mounted on the surface of the multilayer body 2, and this chip component 9 is covered with a metal cap 3 as shown in the perspective view of FIG. 9. As shown in the rear view of FIG. 10, mounting auxiliary pads 6 including partial mounting auxiliary pads 6 a and 6 b connected to a ground terminal of a circuit board (not shown) are formed on the rear surface of the laminate 2. As shown in FIG. 11, the auxiliary mounting pad 6 is connected to the ground electrodes g <b> 1 and g <b> 2 in the multilayer body 2 through the through hole 7. Thereby, the circuit performance of the high-frequency component 1 is improved by obtaining the absolute ground potential of the ground electrodes g1 and g2.
JP2004-222087

  When the high-frequency module 10 shown in FIG. 1 is downsized, the influence of variations in the mounting height of the high-frequency component 16 (that is, variation in residual inductance) on the characteristics of the high-frequency component 16 increases.

  For example, the variation in the mounting height is caused by a variation in the amount of solder applied by screen printing to form the connection conductors 14a to 14f. When the mounting height varies, the apparent L value of the high-frequency component 16 also varies. Since the L value of the high-frequency component 16 such as a conventional SAW duplexer is sufficiently large and the influence of the variation in the L value due to the mounting height is small, the variation in the mounting height has not been a problem. However, as the size and the frequency increase, the L value of the high-frequency component 16 such as a SAW duplexer becomes smaller. Therefore, even if the mounting height variation (that is, the residual inductance variation) is the same, it is given to the characteristics of the high-frequency component 16 The impact will increase.

  In order to suppress variation in the L value, it may be possible to mount the mounting auxiliary pad disclosed in Patent Document 1 on a high frequency component and mount it on a circuit board. The space to be provided cannot be secured.

  That is, if a space for providing the mounting auxiliary pad can be secured, the high frequency module 20 shown in FIG. 2 can be configured. As shown in the exploded perspective view of FIG. 2A and the plan view of FIG. 2B, the high-frequency component 20 includes terminal pads 28a to 28f (28a and 28b are not shown) similar to the conventional ones, Auxiliary mounting pads 28g to 28i (28g and 28h are not shown) electrically connected to the ground electrode inside the high-frequency component 20 through a through hole are added, and the circuit board 22 is also similar to the conventional one. In addition to the connection conductors 24a to 4f, connection conductors 24g to 24i facing the mounting auxiliary pads 28g to 28i (28g and 28h are not shown) of the high-frequency component 20 are added to suppress the occurrence of residual inductance. Conceivable.

  However, when the high-frequency component becomes smaller due to the chip size packaging, as shown in the exploded perspective view of FIG. 3A and the plan view of FIG. In addition to the connection conductors 34a to 34f, the mounting auxiliary pads can be secured in the high frequency circuit component mounting area 38a on the circuit board 32. It becomes impossible to provide an electrode pad or a ground conductor corresponding to the pad.

  In view of such circumstances, the present invention is intended to provide a high-frequency module that can suppress a residual inductance that occurs due to variations in the mounting height of a high-frequency component even if the high-frequency component is downsized.

  In order to solve the above problems, the present invention provides a high-frequency module configured as follows.

  The high-frequency module includes: (a) a circuit board on which a signal electrode pad is formed; (b) a connection conductor formed on the signal electrode pad and protruding from the circuit board; and (c) a terminal pad on the connection conductor. And a high-frequency component that is connected and mounted on the circuit board. The high-frequency module includes: (i) a ground electrode pad formed around a high-frequency component mounting region on which the high-frequency component of the circuit board is mounted; and (ii) formed on the ground electrode pad and protruding from the circuit board. And a ground conductor.

  In the above configuration, when a high-frequency current flows through the connection conductor interposed between the circuit board and the high-frequency component, a magnetic field is generated around the connection conductor and self-inductance is generated. At this time, a current in a direction that prevents a change in the magnetic field flows through the ground conductor formed on the ground electrode pad of the circuit board, and a new magnetic field is generated in a direction that cancels the magnetic field generated around the connection conductor. As a result, a current that cancels the self-inductance due to the high-frequency current is generated in the connection conductor, and the self-inductance of the connection conductor is reduced.

  In other words, by forming a ground conductor on the ground electrode pad of the circuit board, the self-inductance of the connection conductor is canceled by electromagnetic induction, and variation in electrical characteristics due to variations in the height of the connection conductor is reduced. However, a stable high frequency module can be obtained.

  The ground electrode pad and the ground conductor can be formed with a space around the high-frequency component mounting area even if the high-frequency component is downsized. Can be suppressed.

  Preferably, the ground electrode pad is formed adjacent to the signal electrode pad.

  In this case, the effect of canceling the magnetic field generated around the connection conductor can be further enhanced, and a high-frequency module with more stable electrical characteristics can be obtained.

  Preferably, the ground conductor protrudes from the circuit board rather than the connection conductor.

  In this case, the effect of canceling out the magnetic field generated around the connection conductor can be further enhanced, and a high-frequency module with more stable electrical characteristics can be obtained.

  According to the present invention, even if the high-frequency component is downsized, it is possible to suppress residual inductance that occurs due to variations in the mounting height of the high-frequency component.

  Examples of the present invention will be described below with reference to FIGS.

  <Example 1> The high frequency module 50 of Example 1 is demonstrated, referring FIG. 4, FIG.

  As schematically shown in the exploded perspective view of FIG. 4A, the high-frequency module 50 has a SAW duplexer chip component mounted as a high-frequency component 56 on a circuit board 52 of a laminate in which an electric circuit is formed. Is done.

  As shown in the plan views of the circuit board 52 in FIGS. 4A and 4B, the high-frequency component mounting region 56a in which the high-frequency component 56 is mounted on the upper surface 52a of the circuit board 52 as in the conventional example. Connection conductors 54a to 54f such as solder are formed on the inner electrode pads (not shown), and the high frequency component 56 and the circuit board 52 are electrically connected by reflow or the like. That is, as shown in FIG. 4A, connection conductors 54a to 54f are formed facing the terminal pads 58a to 58f (58a and 58b are not shown) of the high frequency component 56, and the terminal pads 58a of the high frequency component 56 are formed. ˜58f (58a and 58b are not shown) are electrically connected to electrode pads (not shown) of the circuit board 52 via connection conductors 54a to 54f, respectively.

  Specifically, via a lead electrode 55 formed inside the circuit board 52, they are electrically connected to a reception terminal, a transmission terminal, and an antenna terminal (not shown) formed on the lower surface 52 b of the circuit board 52, respectively. Connection conductors 54a, 54c, and 54e are formed on the electrode pads (that is, signal electrode pads). In addition, diagonal lines are provided on electrode pads (ground electrode pads) that are electrically connected to a ground terminal (not shown) formed on the lower surface 52b of the circuit board 52 via a lead electrode (not shown). Connection conductors 54b, 54d, and 54f are formed.

  Unlike the conventional example, a ground electrode pad (not shown) electrically connected to a ground terminal (not shown) formed on the lower surface 52b of the circuit board 52 is also formed around the high-frequency component mounting region 56a. Ground conductors 55a to 55f are formed thereon. The ground conductors 55a to 55f are formed simultaneously with the connection conductors 54a to 54f using the same material as the connection conductors 54a to 54f. This is preferable because the process becomes simple. However, the ground conductors 55a to 55f may be formed independently of the connection conductors 54a to 54f.

  When the high frequency component 56 is mounted on the circuit board 52 and the high frequency module 50 is completed, the connection conductors 54a to 54f and the ground conductors 55a to 55f protrude from the circuit board 52. Since the ground electrode pad is disposed in a region adjacent to the signal electrode pad, the hatched ground conductors 55a to 55f and the connection conductors 54b, 54d, and 54f formed on the ground electrode pad are connected through which signals pass. Adjacent to the conductors 54a, 54c, 54e.

  That is, as schematically shown in FIG. 5, the connection conductor 60 and the ground conductors 62 and 64 protrude from the circuit board 52 (see FIG. 4) in the height direction indicated by the arrow 68. When a high-frequency current flows through the connection conductor 60 in the direction indicated by the arrow 60b, a magnetic field in the direction indicated by the arrow 60a is generated around the connection conductor 60, and self-inductance is generated.

  At this time, as shown in FIG. 5B, if there are ground conductors 62 and 64 around the connection conductor 60, arrows 62a and 62 are connected around the ground conductors 62 and 64 that are connected to the ground terminal and are at the ground potential. A new magnetic field is generated in the direction indicated by 64a, that is, in the direction to cancel the magnetic field in the direction indicated by the arrow 60b. Therefore, the magnetic field is canceled around the connection conductor 60, the inductance itself is reduced, and the variation in inductance due to the variation in the height of the connection conductor 60 is also suppressed.

  Since high-frequency current flows through the connection conductors 54a, 54c, and 54e, the self-inductance fluctuates due to variations in the height of the solder. However, as shown in FIG. 4, since the ground conductors 55a to 55f are arranged around the connection conductors 54a, 54c, and 54e, the inductance of the connection conductors 54a, 54c, and 54e is reduced, and the variation in inductance is also suppressed. Is done.

  Therefore, variation in electrical characteristics of the high-frequency component 56 is reduced, and the high-frequency module 50 stable in electrical characteristics can be obtained.

  <Example 2> The high-frequency module 70 of Example 2 will be described with reference to FIGS.

  The high-frequency module 70 of Example 2 shown in FIG. 7A is configured in substantially the same manner as in Example 1, and can be manufactured by substantially the same method.

  As shown in the perspective view of FIG. 6A, solder is printed on the electrode pads 71 a to 71 f and 73 a to 73 f formed on the upper surface 72 a of the circuit board 72 using a mask 90. By at least one printing using the mask 90, as shown in the perspective view of FIG. 6B, solders 96a to 96f for connecting conductors are applied on the electrode pads 71a to 71f (see FIG. 6A). Then, the ground conductor solders 97a to 97f are applied on the electrode pads 73a to 73f (see FIG. 6A). As shown in the perspective view of FIG. 7A, the high frequency module 76 is completed by mounting and reflowing the high frequency component 76.

  As shown in the plan view of the circuit board 72 in FIG. 7B, connection conductors 74a to 74f are formed in the high-frequency component mounting portion 76a on the upper surface 72a of the circuit board 72, and a ground is formed around the high-frequency component mounting area 76a. Conductors 75a to 75f are formed. The electrode pads 71a, 71b, 71e (see FIG. 6A) on which the connection conductors 74a, 74c, 74e are formed are respectively connected to the circuit board 72 via the lead electrodes 75 formed inside the circuit board 72. The signal electrode pad is electrically connected to a receiving terminal, a transmitting terminal, and an antenna terminal (not shown) formed on the lower surface 72b (see FIG. 6A). The hatched connection conductors 74b, 74d, and 74f and the ground conductors 75a to 75f are formed on the hatched ground electrode pads 71b, 71d, 71f, and 73a to 73f in FIG. The ground electrode pads 71b, 71d, 71f, 73a to 73f hatched in FIG. 6A are formed on the lower surface 72b of the circuit board 72 (see FIG. 6A) via lead electrodes (not shown). It is electrically connected to a ground terminal (not shown). As shown to Fig.6 (a), the area of each electrode pad 71a-71f and 73a-73f is the same.

  Unlike Example 1, as shown in FIG. 6A, a mask 90 used for solder printing has openings 94a to 94f for forming connecting conductor solders 96a to 96f (see FIG. 6B). The opening areas of the openings 95a to 95f for forming the ground conductor solders 97a to 97f (see FIG. 6B) are larger than the opening area. Therefore, as shown in FIG. 6B, the amount of solder applied to the ground conductor solders 97a to 97f is larger than the amount of solder applied to the connecting conductor solders 96a to 96f.

  By reflowing in this state, as shown in the perspective view of FIG. 7A, the high-frequency module 70 has the ground conductors 75a to 75f (75a not shown) connected to the connection conductors 74a to 74f (74a). 74b are not shown). That is, the protrusion height from the upper surface 72a of the circuit board 72 is such that the ground conductors 75a to 75f (75a not shown) arranged outside the high frequency component mounting region 76a are located inside the high frequency component mounting region 76a. It becomes larger than the arranged connection conductors 74a to 74f (74a and 74b are not shown).

  As schematically shown in FIG. 8, when a current flows through the connection conductor 80 in the direction indicated by the arrow 80b, a magnetic field is generated in the direction indicated by the arrow 80a, and the ground conductor 82 is connected to the ground terminal and is at the ground potential. , 84 generates a magnetic field in the direction indicated by arrows 82a, 84a. At this time, the ground conductors 82 and 84 have a larger protruding height from the upper surface 72a of the circuit board 72 than the connection conductor 80 in the height direction indicated by the arrow 88, so that the effect of canceling out the inductance is further increased. In addition, the shielding effect is further enhanced by the ground conductors 82 and 84 having a protruding height higher than the connection conductor 80 from the upper surface 72 a of the circuit board 72.

  <Summary> The high-frequency modules according to the first and second embodiments described above can suppress inductance components generated due to variations in the height of connection conductors connecting the circuit board and the high-frequency components. As a result, the electrical characteristics of the high-frequency component are stabilized, the yield is improved, and mass production of the high-frequency module is facilitated. In this embodiment, an example in which the ground conductor is equal to or higher than the connection conductor is shown. However, even when the ground conductor is lower than the connection conductor, if the ground conductor is formed, an inductance component is formed. Can be suppressed.

  Since it is not necessary to increase the number of terminal pads for high-frequency components, it is easy to reduce the size of high-frequency components. It is possible to suppress the inductance component generated due to the variation.

  Further, since it is not necessary to route the ground electrode inside the high frequency component, the high frequency component can be reduced in height.

  Furthermore, by forming a ground conductor around the high-frequency component mounting region, it is possible to reduce the interaction with other components and enhance the shielding effect.

  The present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

  For example, the connection conductor and the ground conductor may be formed by a method other than solder reflow.

(A) It is a disassembled perspective view of a high frequency module, (b) It is a top view of a circuit board. (Conventional example 1) (A) It is a disassembled perspective view of a high frequency module, (b) It is a top view of a circuit board. (Reference Example 1) (A) It is a disassembled perspective view of a high frequency module, (b) It is a top view of a circuit board. (Reference Example 1) (A) It is a disassembled perspective view of a high frequency module, (b) It is a top view of a circuit board. (Example 1) It is explanatory drawing of generation | occurence | production of a magnetic field. (Example 1) (A) It is explanatory drawing of the manufacturing process of a high frequency module, (b) It is a perspective view of a circuit board. (Example 2) (A) Perspective view of high-frequency module, (b) Plan view of circuit board. (Example 2) It is explanatory drawing of generation | occurence | production of a magnetic field. (Example 2) It is a perspective view of a high frequency component. (Conventional example 2) It is a reverse view of a high frequency component. (Conventional example 2) It is sectional drawing of a high frequency component. (Conventional example 2)

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 High frequency module 52 Circuit board 54a-54f Connection conductor 55a-55f Ground conductor 56 High frequency component 56a High frequency component mounting area 70 High frequency module 72 Circuit board 71a, 71c, 71f Signal electrode pad 71b, 71d, 71e Ground electrode pad 73a-73f Ground Electrode pads 74a to 74f Connection conductor 75a to 75f Ground conductor 76 High frequency component 76a High frequency component mounting area 96a to 96f Solder 97a to 97f Solder

Claims (3)

A circuit board on which signal electrode pads are formed;
A connection conductor formed on the signal electrode pad and protruding from the circuit board;
In a high-frequency module comprising a high-frequency component mounted on the circuit board with a terminal pad connected to the connection conductor,
A ground electrode pad formed around a high-frequency component mounting region on which the high-frequency component is mounted on the circuit board;
A ground conductor formed on the ground electrode pad and protruding from the circuit board;
A high-frequency module comprising:   The high-frequency module according to claim 1, wherein the ground electrode pad is formed adjacent to the signal electrode pad.   The high frequency module according to claim 1, wherein the ground conductor protrudes from the circuit board rather than the connection conductor.

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