Patent Publication Number: US-2023163086-A1

Title: Module and method for manufacturing the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation of International Application No. PCT/JP2021/017894 filed on May 11, 2021 which claims priority from Japanese Patent Application No. 2020-098833 filed on Jun. 5, 2020. The contents of these applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a module and a method for manufacturing the same. 
     Description of the Related Art 
     A high-frequency module comprising a wiring board, a resin seal layer, and a shield film is described in International Publication WO2019/004332A1 (PTL 1). In the high-frequency module described in PTL 1, a conductive member is mounted on a major surface of the wiring board, the resin seal layer has a recess formed therein to expose a portion of the conductive member, and the shield film shields a wall surface of the recess and the exposed portion of the conductive member. 
     (PTL 1) International Publication WO2019/004332A1 
     BRIEF SUMMARY OF THE DISCLOSURE 
     However, generally, when a shield film is formed in a recess, the shield film tends to be small in thickness inside a recess provided in a resin seal. In particular, when the shield film is formed in the recess by sputtering, the shield film tends to be smaller in thickness. When the shield film is small in thickness inside the recess, the film may provide insufficient shielding performance. 
     Accordingly, a possible benefit of the present disclosure is to provide a module capable of ensuring sufficient shielding performance even in a recess provided in a resin seal, and a method for manufacturing the module. 
     In order to achieve the above possible benefit, a module according to the present disclosure comprises: a substrate having a first surface; first and second components mounted on the first surface; a conductive member mounted on the first surface between the first and second components; and a resin seal disposed to cover the first surface and the first and second components and also seal a portion of the conductive member, the resin seal having a recess that exposes at least a portion of the conductive member, inside the recess the resin seal and the conductive member having a side surface and a surface, respectively, covered with a first shield film, the first shield film inside the recess being covered with a second shield film smaller in thickness than the first shield film, the resin seal having a surface facing away from the first surface and covered with the second shield film. 
     The present disclosure can provide a module capable of ensuring sufficient shielding performance even in a recess provided in a resin seal. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    is a perspective view of a module according to a first embodiment of the present disclosure. 
         FIG.  2    is a plan view of the module according to the first embodiment of the present disclosure. 
         FIG.  3    is a cross section taken along a line III-III indicated in  FIG.  2   . 
         FIG.  4    is a diagram for illustrating a first step of a method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  5    is a diagram for illustrating a second step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  6    is a diagram for illustrating a third step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  7    is a diagram for illustrating a fourth step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  8    is a cross section of a composite sheet used in the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  9    is a diagram for illustrating a fifth step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  10    is a diagram for illustrating a sixth step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  11    is a diagram for illustrating a seventh step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  12    is a diagram for illustrating an eighth step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  13    is a diagram for illustrating a ninth step of the method for manufacturing the module according to the first embodiment of the present disclosure. 
         FIG.  14    is a partial cross section of a module according to a second embodiment of the present disclosure. 
         FIG.  15    is a partial cross section of a module according to a third embodiment of the present disclosure. 
         FIG.  16    is a partial cross section of a module according to a fourth embodiment of the present disclosure. 
         FIG.  17    is a diagram for illustrating a first step of a method for manufacturing the module according to the fourth embodiment of the present disclosure. 
         FIG.  18    is a diagram for illustrating a second step of the method for manufacturing the module according to the fourth embodiment of the present disclosure. 
         FIG.  19    is a partial cross section of a module according to a fifth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The figures indicate a dimensional ratio, which does not necessarily provide a representation which is faithful to reality, and may be exaggerated for the sake of illustration. In the following description, when referring to a concept of being upper or lower, it does not necessarily mean being absolutely upper or lower and may instead mean being relatively upper or lower in a position shown in a figure. 
     First Embodiment 
     A module according to a first embodiment of the present disclosure will now be described with reference to  FIGS.  1  to  3   .  FIG.  1    shows an external appearance of a module  101  according to the present embodiment. Module  101  has an upper surface and a side surface covered with a shield film  8 .  FIG.  2    is a plan view of module  101 . In  FIG.  2   , components  3   a,    3   b  etc. incorporated in module  101  are also indicated by broken lines. In  FIG.  2   , a recess  10  located at the upper surface of module  101  is visible. A conductive member  5  is located deep behind recess  10 .  FIG.  3    is a cross section taken along a line III-III indicated in  FIG.  2   . Shield film  8  includes a first shield film  81  and a second shield film  82 . 
     Module  101  according to the present embodiment includes a substrate  1  having a first surface  1   a,  first and second components  3   a  and  3   b  mounted on first surface  1   a,  conductive member  5 , and a resin seal  6 . Conductive member  5  is mounted on first surface  1   a  between first component  3   a  and second component  3   b.  Resin seal  6  is disposed to cover first surface  1   a  and first and second components  3   a  and  3   b  and also seal a portion of conductive member  5 . Resin seal  6  has a recess  6   r  that exposes at least a portion of conductive member  5 . Inside recess  6   r  provided in resin seal  6 , resin seal  6  and conductive member  5  have a side surface and a surface, respectively, covered with first shield film  81 . First shield film  81  inside recess  6   r  provided in resin seal  6  is covered with second shield film  82  smaller in thickness than first shield film  81 . Second shield film  82  covers a surface of resin seal  6  facing away from first surface  1   a.  In the present embodiment, first shield film  81  is not a sputtered film. 
     Substrate  1  has first surface  1   a  and a second surface  1   b.  First surface  1   a  and second surface  1   b  face away from each other. A pad electrode  13  and a ground electrode  14  are disposed on substrate  1  at first surface  1   a.  First component  3   a  is mounted via pad electrode  13 . A ground conductor pattern  16  is disposed inside substrate  1 . Ground electrode  14  and ground conductor pattern  16  are electrically connected by a conductor via  15 . Conductive member  5  is mounted so as to be electrically connected to ground electrode  14 . A connection terminal  17  is disposed on substrate  1  at second surface  1   b.  Connection terminal  17  is used to ensure electrical connection when module  101  is mounted on a mother board or the like. 
     In the present embodiment, shield film  8  has a two-layer structure of first shield film  81  and second shield film  82  inside recess  6   r  provided in resin seal  6 , and a module also capable of ensuring sufficient shielding performance in recess  6   r  in which the film would otherwise tend to be small in thickness can be provided. This is particularly effective when the film is formed in the recess by sputtering, as will be described hereinafter. For example, an electromagnetic wave  90  emitted from first component  3   a  is interrupted by shield film  8  located in recess  10 . This can reduce a degree of an effect that electromagnetic wave  90  emitted from first component  3   a  has on second component  3   b.    
     First shield film  81  is preferably a metal grain film. Adopting this configuration allows easy production through a process described hereinafter. 
     First shield film  81  preferably contains silver as a major ingredient. Adopting this configuration allows easy production through a process described hereinafter. 
     Conductive member  5  is preferably a Cu block. Adopting this configuration allows conductive member  5  to be easily implemented. 
     (Manufacturing Method) 
     A method for manufacturing a module according to the present embodiment will now be described with reference to  FIGS.  4  to  13   . 
     Initially, as shown in  FIG.  4   , substrate  1  is prepared. Substrate  1  has first surface  1   a  and second surface  1   b.  Substrate  1  has ground conductor pattern  16  incorporated therein. Subsequently, as shown in  FIG.  5   , first component  3   a,  second component  3   b,  conductive member  5 , etc. are mounted on substrate  1  at first surface  1   a.    
     As shown in  FIG.  6   , resin seal  6  is disposed. Resin seal  6  seals first component  3   a,  second component  3   b,  conductive member  5 , etc. as well as first surface  1   a.  As shown in  FIG.  7   , recess  6   r  is formed in resin seal  6 . Recess  6   r  can be formed by laser processing. Conductive member  5  is exposed at a bottom surface of recess  6   r.  The presence of conductive member  5  prevents laser light from reaching substrate  1 . 
     A film  70  shown in  FIG.  8    is prepared. Film  70  includes a conductive film  71  and a release film  72 . Film  70  is a composite sheet. Conductive film  71  includes metal grains. Conductive film  71  is a metal grain film. Release film  72  is a resin film. Film  70  may be a commercially available film. As shown in  FIG.  9   , film  70  is placed on resin seal  6 . Heating and compression are applied as indicated in  FIG.  10    by arrows  91 . As a result, as shown in  FIG.  10   , film  70  deforms along a shape of a surface of resin seal  6  and adheres to an inner surface of recess  6   r  provided in resin seal  6 . 
     Subsequently, by peeling release film  72 , a structure is obtained as shown in  FIG.  11   . By polishing an upper surface, the structure will be as shown in  FIG.  12   . At this stage, resin seal  6  has an upper surface exposed. Recess  6   r  provided in resin seal  6  has an inner surface covered with first shield film  81 . Sputtering is performed to form second shield film  82  as shown in  FIG.  13   . Note that, on the inner surface of recess  6   r  provided in resin seal  6 , a dual structure of first shield film  81  and second shield film  82  is provided. Resin seal  6  has the upper surface and a side surface covered with second shield film  82 . There is no first shield film  81  on the upper and side surfaces of resin seal  6 . Module  101  shown in  FIGS.  1  to  3    can thus be obtained. 
     Although a structure for a single product has been shown and described herein, a collective substrate corresponding to a plurality of products may be used and each process may collectively be performed. In that case, for example, second shield film  82  may be sputtered after the collective substrate is divided by a size of each individual product. 
     Second Embodiment 
     Referring to  FIG.  14   , a module according to a second embodiment of the present disclosure will now be described.  FIG.  14    is a partial cross section of a module  102  according to the present embodiment. 
     Module  102  has a basic configuration similar to that of module  101  described in the first embodiment except for a configuration of a film covering an upper surface of resin seal  6 . In module  102 , first shield film  81  extends to and on the upper surface of resin seal  6 . On the upper surface of resin seal  6 , shield film  8  has a dual structure of first shield film  81  and second shield film  82 . In other words, in the present embodiment, first shield film  81  is interposed between resin seal  6  and second shield film  82  on a surface of resin seal  6  facing away from first surface  1   a.    
     In the present embodiment, shield film  8  has a dual structure on the upper surface of resin seal  6 , which allows enhanced shielding performance in a direction perpendicular to first surface  1   a  of substrate  1 . 
     Third Embodiment 
     A module according to a third embodiment of the present disclosure will now be described with reference to  FIG.  15   .  FIG.  15    is a partial cross section of a module  103  according to the present embodiment. 
     Module  103  has a basic configuration similar to that of module  102  described in the second embodiment except for a configuration of a film covering a side surface of resin seal  6 . In module  103 , first shield film  81  extends to and on the side surface of resin seal  6 . In other words, in the present embodiment, first shield film  81  covers the side surface of resin seal  6 . On the side surface of resin seal  6 , shield film  8  has a dual structure of first shield film  81  and second shield film  82 . Further, first shield film  81  extends to a lower end of the side surface of substrate  1 . Substrate  1  also has a side surface covered with the dual structure of first shield film  81  and second shield film  82 . Ground conductor pattern  16  is exposed at the side surface of substrate  1 . Ground conductor pattern  16  is electrically connected to first shield film  81  at the side surface of substrate  1 . 
     In the present embodiment, shield film  8  has a dual structure not only on the upper surface of resin seal  6  but also on the side surface thereof, which allows enhanced shielding performance not only in the direction perpendicular to first surface la of substrate  1  but also laterally thereof. 
     As indicated in the present embodiment, preferably, first shield film  81  covers a side surface of substrate  1  and ground conductor pattern  16  as a ground conductor is disposed inside substrate  1  such that ground conductor pattern  16  is exposed at the side surface of substrate  1 , and first shield film  81  is connected to the ground conductor at the side surface of substrate  1 . First shield film  81  electrically connected to ground conductor pattern  16  at the side surface of substrate  1  allows shield film  8  to be sufficiently grounded. 
     Fourth Embodiment 
     A module according to a fourth embodiment of the present disclosure will now be described with reference to  FIG.  16   .  FIG.  16    is a partial cross section of a module  104  according to the present embodiment. 
     Module  104  has a basic configuration similar to that of module  103  described in the third embodiment except for a configuration of shield film  8  on a side surface of substrate  1 . 
     In module  104 , in a vicinity of an end of substrate  1 , first shield film  81  is electrically connected to an upper surface of ground conductor pattern  16 . Second shield film  82  is electrically connected to a side surface of ground conductor pattern  16 . 
     The present embodiment can also be as effective as the third embodiment. In the present embodiment, first shield film  81  and second shield film  82  included in shield film  8  are both directly connected to ground conductor pattern  16 , and shield film  8  can be more sufficiently grounded. 
     Module  104  indicated in the present embodiment can be manufactured as follows. After resin seal  6  is formed, recess  6   r  is formed, and furthermore, as shown in  FIG.  17   , a trench  11  is formed at a position corresponding to a boundary between individual products. At a bottom of trench  11 , an upper surface of ground conductor pattern  16  incorporated in substrate  1  is exposed. After film  70  shown in  FIG.  8    is placed on resin seal  6  and heated and compressed, release film  72  is peeled off. A structure is obtained as shown in  FIG.  18   . Further, each individual product is separated and sputtering or a like method is employed to form second shield film  82 . Thus, module  104  can be obtained. 
     Herein, a method for manufacturing a module can be represented as follows. The method for manufacturing the module comprises: preparing substrate  1  having first surface la, having first component  3   a  and second component  3   b  mounted on first surface  1   a,  and having conductive member  5  mounted between first component  3   a  and second component  3   b;  disposing resin seal  6  so as to cover first surface  1   a,  first component  3   a,  second component  3   b,  and conductive member  5 ; forming recess  6   r  in resin seal  6  so as to expose at least a portion of conductive member  5 ; placing film  70  as a composite sheet including a structure of at least two layers of a metal grain film and a resin film deposited one on the other on an upper side of resin seal  6  such that the metal grain film underlies the resin film, and heating and compressing film  70  to form first shield film  81  of the metal grain film so as to cover a side surface of resin seal  6  and a surface of conductive member  5  inside recess  6   r;  and after forming first shield film  81 , removing the resin film, and after removing the resin film, forming second shield film  82  by sputtering so as to cover an inner surface of recess  6   r.  Module  104  can thus be obtained. 
     Fifth Embodiment 
     A module according to a fifth embodiment of the present disclosure will now be described with reference to  FIG.  19   .  FIG.  19    is a partial cross section of a module  105  according to the present embodiment. 
     Module  105  according to the present embodiment has a so-called double-sided mounting structure. In module  105 , substrate  1  has second surface  1   b  as a surface opposite to first surface  1   a.  Module  105  comprises a third component  3   c  mounted on second surface  1   b.  In module  105 , a resin seal  6   a  is disposed so as to cover first surface  1   a  and first and second components  3   a  and  3   b.  A resin seal  6   b  is disposed so as to cover second surface  1   b  and third component  3   c.  Second shield film  82  also covers a side surface of resin seal  6   b.  A connection terminal  18 , which is a columnar conductor, is mounted on second surface  1   b.  Connection terminal  18  penetrates resin seal  6   b  and is exposed at a lower surface of module  105 . Connection terminal  18  may be covered with some conductor film. Alternatively, connection terminal  18  may be a solder bump. 
     Herein, while third component  3   c  is shown as an example to indicate that at least one component is mounted on second surface  1   b,  a component other than third component  3   c  may be mounted on second surface  1   b.  A plurality of components may be mounted on second surface  1   b.  Some of the plurality of components mounted on second surface  1   b  may have a lower surface exposed from resin seal  6   b.  While the example shown in  FIG.  19    shows third component  3   c  having a lower surface covered with resin seal  6   b,  third component  3   c  may have the lower surface exposed from resin seal  6   b.    
     In the present embodiment, module  105  has a double-sided mounting structure and third component  3   c  is also mounted on substrate  1  at second surface  1   b,  and more components can thus be mounted on substrate  1  having a limited area and it is thus easy to efficiently implement a highly functional module. 
     Note that a plurality of the above embodiments may be combined as appropriate and employed. It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in any respect. The scope of the present disclosure is defined by the terms of the claims, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims. 
       1  substrate,  1   a  first surface,  1   b  second surface,  3   a  first component,  3   b  second component,  5  conductive member  6 ,  6   a,    6   b  resin seal,  6   r  recess,  8  shield film,  10  recess,  11  trench,  13  pad electrode,  14  ground electrode,  15  conductor via,  16  ground conductor pattern,  17 ,  18  connection terminal,  70  film,  71  conductive film,  72  release film,  81  first shield film,  82  second shield film,  90  electromagnetic wave,  91  arrow,  101 ,  102 ,  103 ,  104 ,  105  module.