Abstract:
A method for producing an electronic component module prevents a space from collapsing. The method includes a step of preparing an electronic component including an element substrate, a drive device formed on a principal surface of the element substrate, and a protection device covering the drive device so as to form a space around the drive device; a step of fixing the electronic component on a common substrate such that a principal surface of the common substrate and another principal surface of the element substrate face each other; a step of fixing a reinforcing plate on the protection device of the electronic component; and a step of forming a resin layer on the principal surface of the common substrate such that the electronic component is contained therein.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic component module including an electronic component, such as a SAW (surface acoustic wave) element or a BAW (bulk acoustic wave) element, contained in a resin layer. 
     2. Description of the Related Art 
     As an electronic component such as an existing SAW (surface acoustic wave) element or BAW (bulk acoustic wave) element, for example, an electronic component described in Japanese Unexamined Patent Application Publication No. 2009-159124 is known. In the electronic component, as shown in  FIG. 6 , a drive device  112  is provided on a piezoelectric substrate  110 . In addition, vibration protection films  116  and  118  are formed around the drive device  112 . The vibration protection films  116  and  118  serve to protect the drive device  112 . 
     Furthermore, a space  138  is formed by a protection device  130 . The space  138  is provided so as to ensure a space when an elastic wave or an acoustic wave propagates. The protection device  130  is composed of a first protection film  132 , a second protection film  134 , and a third protection film  136 . 
     Meanwhile, when the electronic component in Japanese Unexamined Patent Application Publication No. 2009-159124 is mounted, the space may be collapsed. In other words, when an electronic component module including the electronic component is produced, after the electronic component is mounted on a common substrate, a resin layer is formed so as to cover the electronic component. When the resin layer is formed by means of molding, relatively-high pressure is applied to resin. Thus, depending on the resin, there is a concern that the protection device is deformed and the space is collapsed. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problems, preferred embodiments of the present invention provide a method for manufacturing an electronic component module and an electronic component module in which a space is prevented from collapsing. 
     A method for manufacturing an electronic component module according to a preferred embodiment of the present invention includes a step of preparing an electronic component including an element substrate, a drive device located on a principal surface of the element substrate, and a protection device arranged to define a space around the drive device and covering the drive device; a step of preparing a common substrate, and mounting and fixing the electronic component on the common substrate by using a mounter such that a principal surface of the common substrate and another principal surface of the element substrate face each other; a step of mounting and fixing a reinforcing plate on the protection device of the electronic component by using a mounter; and a step of forming a resin layer on the principal surface of the common substrate such that the electronic component is contained therein. 
     In the method for manufacturing the electronic component module according to a preferred embodiment of the present invention, in the step of fixing the reinforcing plate, preferably, an adhesive layer is previously formed on a surface of the reinforcing plate, and the reinforcing plate is fixed such that the adhesive layer is located between the protection device and the reinforcing plate. 
     In the method for manufacturing the electronic component module according to a preferred embodiment of the present invention, the reinforcing plate is preferably made of Si. 
     In the method for manufacturing the electronic component module according to a preferred embodiment of the present invention, preferably, the element substrate is a piezoelectric substrate and the drive device includes an interdigital transducer electrode. 
     In the method for manufacturing the electronic component module according to a preferred embodiment of the present invention, preferably, the element substrate is an insulating substrate and the drive device includes a piezoelectric thin film on both surfaces of which electrodes are formed. 
     In the method for manufacturing the electronic component module according to a preferred embodiment of the present invention, preferably, the element substrate is an insulating substrate and the drive device includes a vibrating device made of Si. 
     According to another preferred embodiment of the present invention, an electronic component module includes a common substrate; an electronic component fixed on the common substrate, the electronic component including an element substrate, a drive device located on a principal surface of the element substrate, and a protection device arranged to define a space around the drive device and covering the drive device, the electronic component being mounted and fixed by using a mounter such that a principal surface of the common substrate and another principal surface of the element substrate face each other; a reinforcing plate mounted and fixed on the protection device of the electronic component by using a mounter; and a resin layer located on the principal surface of the common substrate so as to contain the electronic component therein. 
     In the electronic component module according to a preferred embodiment of the present invention, preferably, an adhesive layer is previously formed on the reinforcing plate and the reinforcing plate is fixed such that the adhesive layer is located between the protection device and the reinforcing plate. 
     In various preferred embodiments of the present invention, it is possible to prevent collapse of the space due to the presence of the reinforcing plate. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are a top view and a cross-sectional view showing an electronic component module according to a preferred embodiment of the present invention. 
         FIGS. 2A-2C  are cross-sectional views showing a method for manufacturing the electronic component module according to a preferred embodiment of the present invention. 
         FIG. 3D  is a cross-sectional view showing the method for manufacturing the electronic component module according to a preferred embodiment of the present invention and showing a continuation of  FIGS. 2A-2C . 
         FIG. 4  is a cross-sectional view showing an electronic component used in a preferred embodiment of the present invention. 
         FIG. 5  is a cross-sectional view showing an electronic component used in a preferred embodiment of the present invention. 
         FIG. 6  is a cross-sectional view showing an existing electronic component. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described. 
     First Preferred Embodiment 
       FIGS. 1A and 1B  are a top view and a cross-sectional view showing an electronic component module according to a preferred embodiment of the present invention.  FIG. 1A  is a top view, and  FIG. 1B  is an A-A cross-sectional view of  FIG. 1A . 
     An electronic component module  1  includes a common substrate  46 , an electronic component  10   a , and a resin layer  48 . In the present preferred embodiment, the electronic component module  1  may include an IC element  30 . The electronic component  10   a  and the IC element  30  are fixed on the common substrate  46 . In addition, the resin layer  48  is arranged on a principal surface of the common substrate  46  so as to contain the electronic component  10   a  and the IC element  30  therein. 
     The electronic component  10   a  and the IC element  30  are electrically connected to lands  42  via wires  44 . The lands  42  are provided to electrically connect the electronic component module  1  to an external circuit, and at least some of the lands  42  are exposed on a bottom surface of the electronic component module  1 . 
     Next, a method for manufacturing the electronic component module according to a preferred embodiment of the present invention will be described with reference to cross-sectional views of  FIGS. 2A-2C and 3D . The present preferred embodiment is an example where the electronic component  10   a  is a SAW element. 
     First, as shown in  FIG. 2A , the electronic component  10   a  is prepared. The electronic component  10   a  includes an element substrate  12 , a drive device  16   a , a protection device  18 , a wire  22   a , and a terminal electrode  24 . 
     In the present preferred embodiment, the element substrate  12  is a piezoelectric substrate. A surface acoustic wave propagates on a surface of the piezoelectric substrate. Examples of the material of the piezoelectric substrate include LiTaO 3  and the like. 
     The drive device  16   a  is located on a principal surface of the element substrate  12 . In addition, in the present preferred embodiment, the drive device  16   a  includes an interdigital transducer electrode. Examples of the material of the interdigital transducer electrode include Al and the like. 
     The protection device  18  is arranged to define a space  14  around the drive device  16   a , and covers the drive device  16   a . The protection device  18  has, for example, a three-layer structure. In this case, first, a photosensitive polyimide resin is applied to the entirety of a principal surface of the piezoelectric substrate, such that a resin film is provided. Next, of the resin film, a portion covering the drive device  16   a  and the surrounding thereof is removed by a photolithographic technique. Next, a composite layer of a photosensitive polyimide resin and a sheet material is provided on the resin film. 
     The terminal electrode  24  is formed on the principal surface side of the element substrate  12 . In addition, the wire  22   a  is provided so as to electrically connect the drive device  16   a  to the terminal electrode  24 . It is preferred if the interdigital transducer electrode of the drive device  16   a  and the wire  22   a  are formed by the same process, since it is possible to produce them at a low cost. Examples of a method for forming the interdigital transducer electrode and the wire  22   a  include methods using a thin film process such as a sputtering method. 
     Next, as shown in  FIG. 2B , the common substrate  46  is prepared, and the electronic component  10   a  is fixed on the principal surface of the common substrate  46 . At that time, the electronic component  10   a  is fixed such that the principal surface of the common substrate  46  and another principal surface of the element substrate  12  face each other. First, the electronic component  10   a  is mounted on the common substrate  46  by using a mounter. At that time, the mounter retains the electronic component  10   a  that is previously disposed at a predetermined location, with a suction mechanism or the like. Then, the mounter transfers the electronic component  10   a  onto the common substrate  46  in a state of retaining the electronic component  10   a . Then, the mounter releases the retention of the electronic component  10   a  and mounts the electronic component  10   a  on the common substrate  46 . 
     If an adhesive layer is interposed between the common substrate  46  and the electronic component  10   a , the adhesive layer may be previously provided on the common substrate  46 , or may be provided on a surface of the electronic component  10   a  that faces the common substrate  46 . Then, the electronic component  10   a  is fixed by a solidification process such as heating. Examples of the common substrate  46  include a printed circuit board and a lead frame. 
     Next, although not shown, the terminal electrode and a land are connected to each other via a wire through wire bonding. 
     Next, as shown in  FIG. 2C , a reinforcing plate  28  is fixed on the protection device  18  of the electronic component  10   a.    
     In the present preferred embodiment, an adhesive layer  26  is previously formed on a surface of the reinforcing plate  28 . In this case, it is unnecessary to individually form the adhesive layer  26  on the protection device  18 , and thus it is possible to conduct the manufacture by a simpler process. Examples of the combination of the reinforcing plate  28  and the adhesive layer  26  include one in which a die attach film is formed on a surface of a Si plate, and one in which an adhesive is screen-printed on a Si plate. If the reinforcing plate  28  is made of Si, the reinforcing plate  28  has an advantage that the reinforcing plate  28  is easily processed and the reinforcing plate  28  is easily thinned. 
     Then, the reinforcing plate  28  that has been cut into an appropriate size is mounted on the protection device  18  by using a mounter such that the adhesive layer  26  is located between the protection device  18  and the reinforcing plate  28 . Then, the adhesive layer  26  is solidified by a solidification process such as heating, such that the reinforcing plate  28  is fixed. 
     In this process, it is possible to mount the reinforcing plate  28  by using the mounter that is used when the electronic component  10   a  is mounted. In addition, if the electronic component  10   a  in which the thickness of the protection device  18  is previously increased is prepared, it is hard to increase the thickness of the photosensitive polyimide resin, and there is a problem that the cost is further increased. However, in the case of various preferred embodiments of the present invention, it is possible to fix the reinforcing plate  28  at a lower cost. 
     Next, as shown in  FIG. 3D , the resin layer  48  is formed on the principal surface of the common substrate  46  on which the electronic component  10   a  is fixed. At that time, the resin layer  48  is formed so as to contain the electronic component  10   a . Examples of a method for forming the resin layer  48  include laminate and a resin molding method. At that time, the space  14  is prevented from collapsing due to the presence of the reinforcing plate  28 . 
     At the last, although not shown, the common substrate may be divided and individual electronic component modules may be taken out. In this manner, the electronic component module is produced. 
     It should be noted that in the present preferred embodiment, the electronic component  10   a  and the land are connected to each other via the wire, but may be connected to each other by another connection method such as flip chip bonding. 
     Second Preferred Embodiment 
       FIG. 4  is a cross-sectional view showing an electronic component used in a preferred embodiment of the present invention, and is an example where the electronic component is a BAW element. A drive device and some of wires are omitted. 
     When an electronic component  10   b  is a BAW element, an element substrate  12  is an insulating substrate of Si or the like, and a drive device  16   b  includes a piezoelectric thin film on both surfaces of which electrodes are located. The drive device  16   b  is acoustically isolated from the element substrate  12  via an acoustic isolation layer. Alternatively, a void may be formed in the element substrate  12  instead of the acoustic isolation layer. 
     Third Preferred Embodiment 
       FIG. 5  is a cross-sectional view showing an electronic component used in a preferred embodiment of the present invention, and is an example where the electronic component is an MEMS (Micro Electro Mechanical Systems) element. A drive device and some of wires are omitted. 
     When an electronic component  10   c  is an MEMS element, an element substrate  12  is an insulating substrate of Si or the like, and a drive device  16   c  includes a vibrating device made of Si. Then, the vibrating device is formed by MEMS processing. 
     It should be noted that the present invention is not limited to the above-described preferred embodiments, and it is possible to make various modifications without departing from the gist of the present invention. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.