Abstract:
A module includes a first multilayer wiring board, a second multilayer wiring board having an upper surface facing a lower surface of the first multilayer wiring board, a component mounted on an upper surface of the first multilayer wiring board, a first terminal electrode provided on the lower surface of the first multilayer wiring board, a second terminal electrode provided on the upper surface of the second multilayer wiring board and connected to the first terminal electrode, and a terminal electrode provided on a lower surface of the second multilayer wiring board. This module is manufactured at a preferable yield rate.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a module including a component mounted on a multilayer wiring board. 
       BACKGROUND ART 
       [0002]    Wireless communication devices, such as mobile phones, has been recently demanded to have small sizes. In order to meet this demand, modules used for the wireless communication devices needs to have small sizes and more functions. 
         [0003]      FIG. 5  is a sectional view of conventional module  5001 . In module  5001 , surface-mounted component  103  is mounted onto a land pattern provided on a top surface of multilayer wiring board  101 . Grounding electrodes  104  arranged at multiple positions on the top surface of multilayer wiring board  101  is connected to shield case  105 . A bottom surface of multilayer wiring board  101  has terminal electrode  102  for external connection arranged thereon. 
         [0004]    Inductors and capacitors are provided from patterns in an inner layer portion of multilayer wiring board  101  provides plural functional circuits, such as a filter and a balanced-unbalanced transformer. Functional circuits  107 A and  107 B are arranged laterally adjacently to each other in the inner layer portion of multilayer wiring board  101 . Functional circuits  107 A and  107 B are separated to ensure isolation between them. Functional circuits  107 A and  107 C are arranged adjacently to each other in a thickness direction. Grounding surface  108  provided between functional circuits  107 A and  107 C prevents circuits  107 A and  107 C from electrically coupling to each other. 
         [0005]    Multilayer wiring board  101  including a large number of functional circuits adjacent to each other in its thickness direction includes a large number of layers. In order to simultaneously satisfy desired characteristics of the functional circuits in board  101 , module  5001  decreases its manufacturing yield. 
       SUMMARY OF THE INVENTION 
       [0006]    A module includes a first multilayer wiring board, a second multilayer wiring board having an upper surface facing a lower surface of the first multilayer wiring board, a component mounted on an upper surface of the first multilayer wiring board, a first terminal electrode provided on the lower surface of the first multilayer wiring board, a second terminal electrode provided on the upper surface of the second multilayer wiring board and connected to the first terminal electrode, and a terminal electrode provided on a lower surface of the second multilayer wiring board. 
         [0007]    This module is manufactured at a preferable yield rate. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a sectional view of a module according to Exemplary Embodiment 1 of the present invention. 
           [0009]      FIG. 2A  is a top view of a multilayer wiring board of the module according to Embodiment 1. 
           [0010]      FIG. 2B  is a bottom view of the multilayer wiring board shown in  FIG. 2A . 
           [0011]      FIG. 2C  is a top view of another multilayer wiring board of the module according to Embodiment 1. 
           [0012]      FIG. 2D  is a bottom view of the multilayer wiring board shown in  FIG. 2C . 
           [0013]      FIG. 3  is a sectional view of a module according to Exemplary Embodiment 2 of the invention. 
           [0014]      FIG. 4A  is a top view of a multilayer wiring board of the module according to Embodiment 2. 
           [0015]      FIG. 4B  is a bottom view of the multilayer wiring board shown in  FIG. 4A . 
           [0016]      FIG. 4C  is a top view of another multilayer wiring board of the module according to Embodiment 2. 
           [0017]      FIG. 4D  is a bottom view of the multilayer wiring board shown in  FIG. 4C . 
           [0018]      FIG. 5  is a sectional view of a conventional module. 
       
    
    
     REFERENCE NUMERALS 
       [0000]    
       
           1 A Multilayer Wiring Board (First Multilayer Wiring Board) 
           1 B Multilayer Wiring Board (Second Multilayer Wiring Board) 
           3  Component 
           6 A Terminal Electrode (First Terminal Electrode) 
           6 B Terminal Electrode (Second Terminal Electrode) 
           9 A Top Surface of Multilayer Wiring Board  1 A (First Surface) 
           9 B Bottom Surface of Multilayer Wiring Board  1 A (Second Surface) 
           9 C Top Surface of Multilayer Wiring Board  1 B (Third Surface) 
           9 D Bottom Surface of Multilayer Wiring Board  1 B (Fourth Surface) 
           9 E Exposing Portion 
           11 A Multilayer Wiring Board (First Multilayer Wiring Board) 
           19 A Top Surface of Multilayer Wiring Board  11 A (First Surface) 
           19 B Bottom Surface of Multilayer Wiring Board  11 A (Second Surface) 
           15  Shield Case 
       
     
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Exemplary Embodiment 1 
       [0033]      FIG. 1  is a sectional view of module  1001  according to Exemplary Embodiment 1 of the present invention. Module  1001  includes multilayer wiring board  1 A, and multilayer wiring board  1 B arranged under bottom surface  9 B of multilayer wiring board  1 A. Multilayer wiring board  1 A has top surface  9 A and bottom surface  9 B opposite to top surface  9 A. Multilayer wiring board  1 B has top surface  9 C and bottom surface  9 D opposite to top surface  9 C. 
         [0034]    Multilayer wiring boards  1 A and  1 B are ceramic laminated circuit boards, such as low temperature co-fired ceramic (LTCC) boards. 
         [0035]    Multilayer wiring board  1 A has functional circuits  7 A and  7 B formed therein with a pattern in an inner layer portion of board  1 A. Top surface  9 A of multilayer wiring board  1 A has component  3  mounted thereon. Grounding electrode  4  arranged on top surface  9 A has shield case  5  arranged thereon. Shield case  4  covers component  9 A and is connected to grounding electrode  4 . Terminal electrode  6 A for external connection is provided on bottom surface  9 B of multilayer wiring board  1 A. 
         [0036]    Multilayer wiring board  1 B has functional circuit  7 C formed therein with a pattern in an inner layer portion of board  1 B. Top surface  9 C of multilayer wiring board  1 B faces bottom surface  9 B of multilayer wiring board  1 A. Terminal electrode  6 B is provided on top surface  9 C of multilayer wiring board  1 B. Terminal electrode  2  for external connection is provided on bottom surface  9 D of board  1 B. 
         [0037]    Module  1001  is a front end module connected to an input port of a tuner receiving circuit. In this case, functional circuit  7 A is a band-pass filter connected to an output port of an antenna. Component  3  is an amplifier connected to an output portion of the band-pass filter. Functional circuit  7 B is a low-pass filter connected to an output port of the amplifier. Functional circuit  7 C is a balun connected to an output port of the low-pass filter. 
         [0038]    Conductor patterns formed on top surface  9 A and bottom surface  9 B of multilayer wiring board  1 A and on top surface  9 C and bottom surface  9 D of multilayer wiring board  1 B will be described.  FIGS. 2A and 2B  are top and bottom views of multilayer wiring board  1 A of module  1001 , respectively. Grounding electrodes  4  are arranged on four corners of top surface  9 A of multilayer wiring board  1 A. Components  3  are mounted at positions other than grounding electrode  4 . Terminal electrodes  6 A including plural electrodes provided along the four sides of bottom surface  9 B of multilayer wiring board  1 A and electrodes provided on bottom surface  9 B from a central portion of bottom surface  9 B to the four corners of bottom surface  9 B. 
         [0039]      FIGS. 2C and 2D  are top and bottom views of multilayer wiring board  1 B of module  1001 , respectively. Terminal electrodes  6 B are provided on top surface  9 C of multilayer wiring board  1 B at positions arranged to contact terminal electrodes  6 A on bottom surface  9 B of multilayer wiring board  1 A shown in  FIG. 2B , respectively. 
         [0040]    Multilayer wiring boards  1 A and  1 B are manufactured separately. Terminal electrodes  6 A on multilayer wiring board  1 A is electrically connected to terminal electrodes  6 B on multilayer wiring board  1 B with conductive adhesives, such as solder, respectively. This method allows multilayer wiring boards  1 A and  1 B can be inspected separately, namely, functional circuits  7 A and  7 C can be inspected separately, and functional circuits  7 B and  7 C can be inspected separately. Non-defective boards of multilayer wiring boards  1 A and  1 B are connected, thereby allowing module  1001  to be manufactured at a higher yield rate than a conventional multilayer wiring board  1  shown in  FIG. 5 . 
         [0041]    If functional circuit  7 C in multilayer wiring board  1 B is not required, terminal electrodes  6 A of multilayer wiring board  1 A may be used as terminal electrodes for external connection. Module  1001  is thus easily changed in its functions and is mounted into various devices. 
         [0042]    Module  1001  according to this embodiment includes two of multilayer wiring boards  1 A and  1 B, however, may be include three or more of the boards with the same effects. 
       Exemplary Embodiment 2 
       [0043]      FIG. 3  is a sectional view of module  1002  according to Exemplary Embodiment 2 of the present invention. In  FIG. 3 , the same components as those of module  1001  according to Embodiment 1 shown in  FIG. 1  are denoted by the same reference numerals, and their description will be omitted. Module  1002  includes multilayer wiring board  11 A instead of multilayer wiring board  1 A of module  1001  shown in  FIG. 1 , and shield case  15  instead of shield case  5 . Multilayer wiring board  11 A has top surface  19 A and bottom surface  19 B opposite to top surface  19 A. Multilayer wiring board  11 A has an area smaller than that of multilayer wiring board  1 B. Top surface  9 C of multilayer wiring board  1 B thus has exposing portion  9 E exposing outside multilayer wiring board  11 A. In module  1002 , grounding electrode  14  is provided on exposing portion  9 E of top surface  9 C of multilayer wiring board  1 B. Shield case  15  covers component  3  and multilayer wiring board  11 A is arranged and connected. 
         [0044]    Conductor patterns provided on top surface  19 A and bottom surface  19 B of multilayer wiring board  11 A and on top surface  9 C and bottom surface  9 D of multilayer wiring board  1 B will be described.  FIGS. 4A and 4B  are top and bottom views of multilayer wiring board  11 A of module  1002 , respectively. Component  3  is mounted on top surface  19 A of multilayer wiring board  11 A. 
         [0045]      FIGS. 4C and 4D  are top and bottom views of multilayer wiring board  1 B of module  1002 , respectively. Terminal electrodes  6 B are provided on top surface  9 C of multilayer wiring board  1 B. Terminal electrodes  6 B contact terminal electrodes  6 A provided on bottom surface  19 B of multilayer wiring board  11 A shown in  FIG. 4B . Grounding electrodes  14  are provide on a periphery of terminal electrodes  6 B. Grounding electrodes  14  is provide at exposing portion  9 E on top surface  9 C of multilayer wiring board  1 B. 
         [0046]    In module  1002 , multilayer wiring boards  11 A and  1 B are manufactured separately, similarly to module  1001  according to Embodiment 1 shown in  FIG. 1 . Terminal electrodes  6 A on multilayer wiring board  11 A is electrically connected to terminal electrodes  6 B on multilayer wiring board  1 B with conductive adhesives, such as solder, respectively. This method allows multilayer wiring boards  11 A and  1 B, namely, functional circuits  7 A and  7 C are inspected separately, and functional circuits  7 B and  7 C are inspected separately. Non-defective boards of multilayer wiring boards  11 A and  1 B are connected, thereby allowing module  1002  to be manufactured at higher yield rate than a conventional multilayer wiring board  101  shown in  FIG. 5 . 
         [0047]    If functional circuit  7 C in multilayer wiring board  1 B is not required, terminal electrodes  6 A provided on multilayer wiring board  1 A may be used as terminal electrodes for external connection. Module  1002  is thus easily changed in its functions and is mounted into various devices. 
         [0048]    Module  1002  suppresses noises input into functional circuits  7 A and  7 B in multilayer wiring board  11 A from sides of multilayer wiring board  11 A. Shield case  15  is connected to grounding electrode  14  provided on top surface  9 C of multilayer wiring board  1 B, hence necessitating a grounding electrode on top surface  19 A of multilayer wiring board  11 A, thus allowing multilayer wiring board  11 A to have a small size. 
       INDUSTRIAL APPLICABILITY 
       [0049]    A module according to the present invention can be manufactured at a high yield rate, and is useful for wireless communication devices, such as mobile phones, having high functions.