PATENT DOCUMENT

Publication Number: US-12148741-B2
Application Number: US-202217806412-A
Country: US
Kind Code: B2

Title: Sidewall connections and button interconnects for molded SiPs

Abstract:
Electronic modules and methods of fabrication are described. In an embodiment, an electronic module includes a molded system-in-package, and a flexible circuit mounted on a side surface of a molding compound layer such that the flexible circuit is in electrical contact with a lateral interconnect exposed along the side surface of the molding compound layer.

Claims:
What is claimed is: 
     
       1. An electronic module comprising:
 a system-in-package including:
 a routing substrate; 
 a first electronic component mounted on a first side of the routing substrate and encapsulated in a first molding compound layer; and 
 a socket connector housing mounted on the routing substrate and within a cavity in the first molding compound layer, the socket connector housing including a side receptacle opening; 
 wherein the cavity is exposed along a first side surface of the first molding compound layer; 
 
 a flexible circuit extending into the cavity from outside the first molding compound layer and connected inside the side receptacle opening of the socket connector housing. 
 
     
     
       2. The electronic module of  claim 1 , further comprising a shield can over the socket connector housing and embedded within the first molding compound layer. 
     
     
       3. The electronic module of  claim 2 , wherein the cavity is defined by the shield can. 
     
     
       4. The electronic module of  claim 3 , comprising an open space separating a top surface of the socket connector housing and a lid of the shield can. 
     
     
       5. The electronic module of  claim 3 , wherein a lid of the shield can is directly on a top surface of the socket connector housing. 
     
     
       6. The electronic module of  claim 2 , wherein the socket connector housing is laterally offset from the first side surface of the first molding compound layer. 
     
     
       7. The electronic module of  claim 1 , further comprising an adhesive applied around the flexible circuit and adjacent the side receptacle opening to secure the flexible circuit inside the side receptacle opening. 
     
     
       8. The electronic module of  claim 1 , wherein the socket connector housing includes a plurality of spring compression contacts. 
     
     
       9. The electronic module of  claim 8 , wherein the plurality of spring compression contacts includes a top group of spring compression contacts and a bottom group of spring compression contacts. 
     
     
       10. The electronic module of  claim 9 , wherein the flexible circuit includes a top group of contacts directly connected to the top group of spring compression contacts and a bottom group of contacts directly connected to the bottom group of spring compression contacts. 
     
     
       11. The electronic module of  claim 1 , wherein the flexible circuit includes a plurality of spring compression contacts inserted into the socket connector. 
     
     
       12. The electronic module of  claim 1 , further comprising a shield can over the socket connector housing and embedded within the first molding compound layer, wherein the shield can is electrically conductive. 
     
     
       13. The electronic module of  claim 1 , further comprising a shield can over the socket connector housing and embedded within the first molding compound layer, wherein the shield can is electrically insulating. 
     
     
       14. The electronic module of  claim 1 , further comprising an integrated electronic component mounted on the flexible circuit, wherein the integrated electronic component is electrically connected with the routing substrate. 
     
     
       15. The electronic module of  claim 14 , wherein the electronic component comprises a sensor. 
     
     
       16. The electronic module of  claim 15 , wherein the system-in-package and the flexible circuit are secured in a housing, and the sensor is oriented adjacent an opening in the housing.

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 17/407,670 filed Aug. 20, 2021, which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Field 
     Embodiments described herein relate to electronic modules, and methods of connecting various systems or subsystems. 
     Background Information 
     The current market demand for portable and mobile electronic devices such as mobile phones, personal digital assistants (PDAs), digital cameras, portable players, gaming, wearables, and other mobile devices requires the integration of more performance and features into increasingly smaller spaces where available module substrate area may be restricted. 
     Flexible printed circuit boards (PCB), also referred to as flexible circuits, flex boards, or flexible printed circuits, are becoming more common, where unlike traditional rigid PCBs, the flexible PCBs can be bent, folded or twisted during use or to meet design objectives. Such flex boards commonly include a flexible substrate (e.g. polymer such as polyimide, polyester, polyethylene naphthalate, etc.) with laminated circuit pattern (e.g. metal foil pattern such as copper) on one or both sides of the flexible substrate. In one implementation, electronic modules include various systems or subsystems mounted onto areas of a flexible circuit. For wearable devices in particular, various systems or subsystems, such as sensors, may be secured in a specific location for interaction with the user or environment. This may be accomplished by manipulating the flexible circuit to adjust location of the target system or subsystem. 
     SUMMARY 
     Electronic modules and methods of assembly are described. In an embodiment, an electronic module includes a flexible module routing substrate and a plurality of systems mounted on the flexible module routing substrate. A system-in-package (SiP) is also mounted on the flexible module routing substrate. The SiP may include a lateral interconnect encapsulated in a molding compound, and a flexible circuit is mounted on a side surface of the molding compound layer where the lateral interconnect is exposed such that a landing pad of the flexible circuit is in electrical contact with the lateral interconnect. In this manner a right angle sidewall interconnection can be made. 
     In an embodiment, an electronic module includes a SiP including a routing substrate, and a first electronic component mounted on a first side of the routing substrate and encapsulated in a first molding compound layer. A first lateral interconnect may be bonded to the first side of the routing substrate and also encapsulated in the first molding compound layer. In an embodiment, the first lateral interconnect is exposed along a side surface of the first molding compound layer. A flexible circuit can be mounted on the first side surface of the first molding compound layer such that a first landing pad of the flexible circuit is in electrical contact with the first lateral interconnect exposed along the first side surface of the first molding compound layer. 
     In another embodiment, side surface interconnection for an SiP is accomplished with a socket connector housing. An electronic module can include an SiP that includes a routing substrate and a first component mounted on a first side of the routing substrate and encapsulated in a first molding compound layer. A socket connector housing can also be mounted on the routing substrate and within a cavity in the first molding compound layer, where the cavity is exposed along a first side surface of the first molding compound layer. The socket connector housing can include a side receptacle opening to receive a flexible circuit, which can be inserted into the cavity from outside the first molding compound layer and connected inside the side receptacle opening of the socket connector housing. 
     In another embodiment, an electronic module includes a SiP that includes a routing substrate and a first component mounted on a first side of the routing substrate and encapsulated in a first molding compound layer. A vertical interconnect may be bonded to the first side of the routing substrate and also encapsulated in the first molding compound layer. In an embodiment, a portion of the first vertical interconnect protrudes form a top exterior surface of the first molding compound layer, and an electronic assembly is bonded to the vertical interconnect of the SiP with a solder material. For example, this may be facilitated by placing a reflowable button around the vertical interconnect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic cross sectional side view illustration of an electronic module including a module routing substrate and a plurality of components and systems or subsystems mounted on the module routing substrate in accordance with an embodiment. 
         FIG.  2 A  is a cross-sectional side view illustration of an electronic module including a pin or wirebond wire lateral interconnect in accordance with an embodiment. 
         FIG.  2 B  is a cross-sectional side view illustration of an electronic module including a stud or solder bump stack lateral interconnect in accordance with an embodiment. 
         FIG.  3 A  is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP with a continuous bonding layer film in accordance with an embodiment. 
         FIG.  3 B  is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP with a plurality of separate bonding layer films in accordance with an embodiment. 
         FIG.  4 A  is a close-up cross-sectional side view illustration for bonding a flexible circuit to SiP with an anisotropic conductive film in accordance with an embodiment. 
         FIG.  4 B  is a close-up cross-sectional side view illustration for bonding a flexible circuit to SiP with a self-alignment paste in accordance with an embodiment. 
         FIG.  5    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP with a plurality of separate solder bumps in accordance with an embodiment. 
         FIG.  6    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP with a plurality of separate button joints in accordance with an embodiment. 
         FIG.  7    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP through a side via in accordance with an embodiment. 
         FIGS.  8 A- 8 C  are cross-sectional side view illustrations of method of forming an electronic module including a pin or wirebond wire lateral interconnect in accordance with an embodiment. 
         FIGS.  9 A- 9 C  are cross-sectional side view illustrations of method of forming an electronic module including a stud or solder bump stack lateral interconnect in accordance with an embodiment. 
         FIGS.  10 A- 10 C  are cross-sectional side view illustrations of method of forming an electronic module including a flexible circuit bonded to an SiP through a side via in accordance with an embodiment. 
         FIG.  11    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP through a socket connector housing in accordance with an embodiment. 
         FIG.  12    is an isometric view illustration of a flexible circuit and socket connector housing in accordance with an embodiment. 
         FIGS.  13 A- 13 D  are cross-sectional side view illustrations of method of forming an electronic module including socket connector housing for receiving a flexible circuit in accordance with an embodiment. 
         FIGS.  14 A- 14 B  are cross-sectional side view illustrations of method of forming an electronic module including a 3D molded stack and button joints in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe electronic modules and methods of assembly. In an embodiment, an electronic module includes a system-in-package (SiP) and flexible circuit connected with the SiP. The SiP may include a routing substrate, such as a flexible or rigid printed circuit board (PCB), a first electronic mounted on a first side of the routing substrate and encapsulated in a first molding compound layer, and a first lateral interconnected bonded to the first side of the routing substrate and encapsulate din the first molding compound layer, and exposed along a first side surface of the first molding compound layer. In accordance with embodiments, the flexible circuit can be mounted on the first side surface of the first molding compound layer, where a first landing pad of the flexible circuit is in electrical contact with the first lateral interconnect exposed along the first side surface of the first molding compound layer. In this manner, the first lateral interconnect can form a right angle interconnection connection of a flexible circuit to the SiP. 
     In one aspect, side surface lateral interconnects (such as a right angle interconnect) for SiP may be incorporated due to constrained space on top or bottom sides of a molded SiP. Such configurations thus can leverage previously unused sidewall space for forming SiP to SiP or other peripheral assembly or subassembly interconnections for efficient space utilization. In addition, routing for the SiP routing substrate can be simplified. Furthermore, the SiP top and bottom sides can then be utilized for functions such as electromagnetic interference (EMI) shielding or an antenna in the constrained space available, while the connected peripheral SiP, assembly, or subassembly can be located with less interference that an overlying an EMI shielding or antenna could otherwise potentially cause. 
     In accordance with embodiments, an electronic module is fabricated using the application of solder button joints onto an exposed vertical interconnect feature, such as a wire bond pillar, copper pillar or pin, solder ball stack, etc., that protrudes from a molding compound. Such a fabrication technique can be leveraged for electronic assemblies including lateral interconnects, as well as for fabricating three-dimensional 3D molded stacks. This may allow for miniaturization without substantial changes at system level as the button joint features can be part of an assembly or subassembly that is mounted onto another assembly or subassembly that is not redesigned. 
     In various embodiments, description is made with reference to figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions and processes, etc., in order to provide a thorough understanding of the embodiments. In other instances, well-known semiconductor processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the embodiments. Reference throughout this specification to “one embodiment” means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     The terms “over”, “to”, “between”, and “on” as used herein may refer to a relative position of one layer with respect to other layers. One layer “over”, or “on” another layer or bonded “to” or in “contact” with another layer may be directly in contact with the other layer or may have one or more intervening layers. One layer “between” layers may be directly in contact with the layers or may have one or more intervening layers. 
     Referring now to  FIG.  1    a schematic cross sectional side view illustration of an electronic module including a module routing substrate  220  and a plurality of components  215  and systems or subsystems  225  and system-on-packager (SiP)  125  mounted on the module routing substrate  220 . In an embodiment, SiP  125  is mounted adjacent an end or edge of the module routing substrate  220 . As shown the module routing substrate  220  may be flexible, and bent into a variety of shapes in order to fit into an irregular shaped housing. For example, the module routing substrate  220  may include flexible dielectric layers (e.g. polymer such as polyimide, polyester, polyethylene nphthalate, etc.) with laminated circuit patterns (e.g. metal foil pattern such as copper) on one or both sides of the flexible dielectric layers. Multiple layer module routing substrates  220  can include multiple layers of laminated metal foil layers including metal routing layers, as well as top and bottom side passivation (e.g. polyimide). 
     In accordance with embodiments, a system or subsystem  145  can be mounted onto a side surface of SiP  125  utilizing a flexible circuit  140  and lateral interconnects  130 ,  150 . The flexible circuit  140  may be formed of similar materials as the module routing substrate  220 , though of smaller scale. As shown, the SiP  125  may include electronic components  110 ,  111 ,  112  on both sides of a routing substrate  101 , and be molded on both sides. The electronic components  110 ,  111 ,  112  may be attached using a suitable manner, such as solder bumps  115  (or micro bumps), conductive films, conductive pastes, wirebonding, etc. 
     Additionally, the routing substrate  101  may be electrically connected to the module routing substrate  220  through an interposer  210  including interconnects  212 . In accordance with embodiments, an additional system or subsystem  145  can be directly connected to a side surface of the SiP  125  using one or more lateral interconnects  130 ,  150  and flexible circuit  140 . In this manner, routing complexity of the module routing substrate  220  can be reduced. Additionally, total thickness of the module may be reduced. 
     Referring now to  FIGS.  2 A- 2 B ,  FIG.  2 A  is a cross-sectional side view illustration is provided of an electronic module  100  including a pin or wirebond wire lateral interconnect  130 ,  150  in accordance with an embodiment;  FIG.  2 B  is a cross-sectional side view illustration of an electronic module  100  including a metal stud bump or solder bump stack lateral interconnect  130 ,  150  in accordance with an embodiment. The lateral interconnects of  FIG.  2 B  may each include a single metal stud bump (e.g. copper stud) or solder bump, or a stack thereof. As shown in each of  FIGS.  2 A- 2 B , the electronic module  100  includes a system-in-package (SiP)  125  and flexible circuit  140  mounted on the SiP  125 . The flexible circuit  140  can include landing pads  142  (e.g. copper pads) in electrical connection with the lateral interconnects  130 ,  150 . The flexible circuit  140  can additionally be secured in place with a mechanical stiffener  170  on a side opposite the SiP  125 . The flexible circuit  140  may be a part of a separate system or subsystem  145 , and can include one or more additional integrated electronic components  141 . In an embodiment, the integrated electronic component  141  includes a sensor oriented adjacent an opening  202  in a housing  200  within which the electronic module  100  is secured. 
     In the illustrated embodiment the SiP  125  can include a routing substrate  101 , such as a flexible or rigid PCB, a first electronic component  110  mounted on a first side  102  of the routing substrate (e.g. with solder bumps  115 , etc.) and encapsulated in a first molding compound layer  120 , and a first lateral interconnect  130  bonded to the first side  102  of the routing substrate  101 . The first lateral interconnect  130  is also encapsulated in the first molding compound layer  120  and is exposed along a first side surface  122  of the first molding compound layer  120 . For example, this may be accomplished using a singulating/cutting operation or patterning (e.g. etching, drilling, etc.) of the first molding compound layer  120  to expose the first lateral interconnect  130 . As shown, a flexible circuit  140  is mounted on the first side surface  122  of the first molding compound layer  120  such that a first landing pad  142  of the flexible circuit  140  is in electrical contact with the first lateral interconnect  130  that is exposed along the first side surface  122  of the first molding compound layer  120 . 
     The routing substrate  101  in accordance with embodiments can be a rigid substrate or flexible substrate. In an embodiment, the routing substrate  101  is a laminate. For example, the routing substrate  101  can be a composite of woven fiberglass cloth and polymer (e.g. resin) and metal routing layers. The routing substrate  101  may be formed of a variety of suitable printed circuit board materials including FR4, prepreg, polyimide, etc. The routing substrate  101  may be rigid or flexible. 
     The SiP  125  may include components mounted on both sides of the routing substrate  101 . A second electronic component  111  can also be mounted on a second side  104  (e.g. opposite the first side  102 ) of the routing substrate  101  and encapsulated in a second molding compound layer  160 . Similarly, a second lateral interconnect  150  can be bonded to the second side  104  of the routing substrate  101 , encapsulated in the second molding compound layer  160 , and exposed along a second side surface  162  of the second molding compound layer  160 . The second side surface  162 , and first side surface  122  may be co-planar, and created with the same singulating or cutting operation. The flexible circuit  140  may also be mounted on the second side surface  162  of the second molding compound layer  160 , with a second landing pad  142  of the flexible circuit  140  in electrical contact with the second lateral interconnect  150  exposed along the second side surface  162  of the second molding compound layer  160 . 
     It is to be appreciated that while only a single first electronic component  110  is illustrated as being mounted on the first side  102  of the routing substrate  101 , a plurality of first electronic components  110  can be mounted. Similarly, a plurality of second electronic components  111  can be mounted on the second side  104  of the routing substrate  101 . Both possibilities are illustrated generally with additional electronic components  112  in  FIG.  2 A  mounted on both sides of the routing substrate  101 . The electronic components in accordance with embodiments can be dies ranging from system-on-chip (SOC) to memory, passive components (resistors, capacitors, inductors, etc.), micro-electromechanical systems (MEMS), sensors, etc. A variety of configurations of different electronic components is understood. 
     The flexible circuits  140  in accordance with embodiments can be attached to the SiP  125  using a suitable material to provide adhesion and electrical connection with landing pads  142 .  FIG.  3 A  is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit  140  bonded to an SiP  125  with a continuous bonding layer film  180  in accordance with an embodiment.  FIG.  3 B  is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit  140  bonded to an SiP  125  with a plurality of separate bonding layer films  180  in accordance with an embodiment. For example, a separate bonding layer film may be applied for each landing pad  142 . It is to be appreciated that while separate bonding layer films  180  are illustrated for different lateral interconnects  130 ,  150  in  FIGS.  3 A- 3 B , this is applicable for either configuration, which can be partly dependent on surface area of the exposed lateral interconnects  130 ,  150  and bonding alignment capabilities. It may additionally be possible to form wider lateral interconnects  130 ,  150  with U-shaped copper pins than wirebond wires, for example, with better alignment. For example, a wirebond wire in accordance with an embodiment can have a maximum width of 25-75 μm where exposed along the first side surface of the first molding compound layer. In an embodiment, a copper pin can have a maximum width of 250-500 μm where exposed along the first side surface of the first molding compound layer. Larger areas can be provided with metal stud bumps, solder bumps, etc. 
       FIG.  4 A  is a close-up cross-sectional side view illustration for bonding a flexible circuit  140  to SiP  125  with an anisotropic conductive film in accordance with an embodiment. As shown, an anisotropic film (bonding layer film) can include an adhesive matrix  182  such as epoxy, and a conductive filler such as metal particles  184 . Upon application of heat and pressure, particles sandwiched between the landing pads  142  and lateral interconnects  130 ,  150  provide an electrically conductive path, and the adhesive matrix is cured. 
       FIG.  4 B  is a close-up cross-sectional side view illustration for bonding a flexible circuit  140  to SiP  125  with a self-alignment paste in accordance with an embodiment. As shown, a self-alignment paste (bonding layer film) can include an adhesive matrix  182  such as epoxy, and a conductive filler such as solder particles  186 . Upon application of heat the solder particles coalesce and form solder joints  185  between the landing pads  142  and lateral interconnects  130 ,  150  provide an electrically conductive path, and the adhesive matrix is cured. 
     Referring now to  FIG.  5   , a close-up cross-sectional side view illustration is provided of an electronic module including a flexible circuit  140  bonded to an SiP  125  with a plurality of separate solder bumps  115  (bonding layer films) in accordance with an embodiment. 
       FIG.  6    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit  140  bonded to an SiP  125  with a plurality of separate button joints in accordance with an embodiment. In the illustrated embodiment, the lateral interconnects  130 ,  150  may protrude from the side surfaces  122 ,  162  of the molding compound layers  120 ,  160 . A solder material (bonding layer film  180 ) bonds the lateral interconnects to the flexible circuit  140 . As shown, this can be accomplished by first placing buttons  187  around the protruding lateral interconnects, and optional top solder paste  188 . In an embodiment the buttons include a center hole that fits around the protruding lateral interconnect. For example, the buttons may be ring shaped. The buttons  187  may be formed of a reflowable solder material. Upon applying heat and pressure the buttons  187  and solder paste  188  can reflow to create a solder joint. 
     Referring now to  FIG.  7    is a close-up cross-sectional side view illustration is provided for an electronic module including a flexible circuit  140  bonded to an SiP  125  through a side via  127 ,  167  formed in the molding compound layer  120 , 1   60  in accordance with an embodiment. As shown the lateral interconnects  130 ,  150  can include a vertical interconnect of one or more solder bumps  135 ,  155  metal stud bumps, wire, etc. and a side solder bump  190  or other conductive filler within side vias  127 ,  167 . As shown, side vias  127 ,  167  are formed in the side surfaces  122 ,  162  of the molding compound layers  120 ,  160  and a solder bumps  190  can be used to bond the flexible circuit  140 . The solder bumps  190  may at least partially, or fully, fill the side vias  127 ,  167  after reflow. 
       FIGS.  8 A- 8 C  are cross-sectional side view illustrations of method of forming an electronic module including a pin or wirebond wire lateral interconnect in accordance with an embodiment. Specifically, the process flow of  FIGS.  8 A- 8 C  can be used to fabricate the electronic module of  FIG.  2 A . Initially the one or more electronic components  110 ,  111  and additional electronic components  112  are surface mounted on the routing substrate  101  as shown in  FIG.  8 A . 
     Additionally, the lateral interconnects  130 ,  150  can be added. For example, copper pins can be surface mounted in a U-shape loop structure. Similarly wire bond wire loops can be bonded in a U-shape loop structure. 
     One or both sides of the routing substrate  101  can then be overmolded (encapsulated) with molding compound layers  120 ,  160  as shown in  FIG.  8 B . The U-shape loop structures, molding compound layer, and routing substrate can then be cut (e.g. singulation process) to expose a portion of the lateral interconnects along the side surfaces of the molding compound layers, resulting in the structure illustrated in  FIG.  8 C . The extension section which has been singulated may be a part of another SiP, or a dummy feature. A flexible circuit  140  can then be bonded to the singulated side surfaces  122 ,  162  of the molding compound layers  120 ,  160  with exposed lateral interconnects  130 ,  150  using a suitable bonding layer film such as previously described with regard to  FIGS.  3 A- 5   . 
     In an alternative process flow, the molding operation does not entirely cover the U-shaped loop structures. Thus, after molding, and singulation the lateral interconnects  130 ,  150  may extend from the side surfaces  122 ,  162  of the molding compound layers. Button joints may then be used for bonding with the flexible circuit  140  as described with regard to  FIG.  6   . 
       FIGS.  9 A- 9 C  are cross-sectional side view illustrations of method of forming an electronic module including a stud or solder bump stack lateral interconnect in accordance with an embodiment. Specifically, the process flow of  FIGS.  9 A- 9 C  can be used to fabricate the electronic module of  FIG.  2 B . Initially the one or more electronic components  110 ,  111  and additional electronic components  112  are surface mounted on the routing substrate  101  as shown in  FIG.  8 A . Additionally, the lateral interconnects  130 ,  150  can be added. For example, lateral metal stud bumps or solder bumps can be added. Metal stud bumps can be mounted using a solder or conductive material. Additionally, stacks of metal stud bumps or solder bumps can be added. 
     One or both sides of the routing substrate  101  can then be overmolded with molding compound layers  120 ,  160  as shown in  FIG.  9 B . The lateral interconnects  130 ,  150  can then be singulated, for example, in a wafer sawing operation, resulting in the structure illustrated in  FIG.  9 C . The extension section which has been singulated may be a part of another SiP, or a dummy feature. A flexible circuit  140  can then be bonded to the singulated side surfaces  122 ,  162  of the molding compound layers  120 ,  160  with exposed lateral interconnects  130 ,  150  using a suitable bonding layer film such as previously described with regard to  FIGS.  3 A- 5   . 
       FIGS.  10 A- 10 C  are cross-sectional side view illustrations of method of forming an electronic module including a flexible circuit bonded to an SiP through a side via in accordance with an embodiment. Specifically, the process flow of  FIGS.  10 A- 10 C  can be used to fabricate the electronic module of  FIG.  7   . Initially the one or more electronic components  110 ,  111  and additional electronic components  112  are surface mounted on the routing substrate  101  as shown in  FIG.  10 A . Additionally, the lateral interconnects  130 ,  150  can be added. For example, lateral metal stud bumps or solder bumps can be added similarly as described with regard to  FIG.  9 A . Metal stud bumps can be mounted using a solder or conductive material. Additionally, stacks of metal stud bumps or solder bumps can be added. 
     One or both sides of the routing substrate  101  can then be overmolded with molding compound layers  120 ,  160  as shown in  FIG.  10 B . With the stacks of metal stud bumps or solder bumps encapsulated inside the molding compound layers. Side vias  127 ,  167  are then formed in the side surfaces  122 ,  162  of the molding compound layers  120 ,  160  to expose the stacks of metal stud bumps or solder bumps. As shown in FIG.  9 C 10 C, solder bumps  190  can be added to the side vias  127 ,  167 . A flexible circuit  140  can then be bonded directly to the solder bumps  190 . 
     In an alternative process flow, rather than forming and aligning sidewall interconnects directly with a singulated side surface of a molding compound a socket connector housing can be mounted on the routing substrate, and subsequently exposed with singulation. In this manner, size and alignment of connections can be precisely and repeatably controlled. 
       FIG.  11    is a close-up cross-sectional side view illustration of an electronic module including a flexible circuit bonded to an SiP through a socket connector housing in accordance with an embodiment.  FIG.  12    is an isometric view illustration of a flexible circuit and socket connector housing in accordance with an embodiment. Referring now to both  FIGS.  11 - 12   , in an embodiment an electronic module  100  includes a SiP  125  similar to previous descriptions. The primary difference of the embodiments illustrated in  FIGS.  11 - 12    is with the integration of the socket connector housing  260  for sidewall interconnection to the SiP  125 . In interest of clarity and conciseness, similarities with previously described embodiments are not repeated in the following description. 
     As shown, the SiP  125  includes a routing substrate  101  and a first electronic component  110  mounted on a first side  102  of the routing substrate  101  and encapsulated in a first molding compound layer  120 . A socket connector housing  260  is also mounted on the routing substrate  101  and within a cavity  272  in the first molding compound layer  120 . For example, the socket connector housing  260  may be surface mounted with solder bumps  115  to facilitate bonding and electrical connection with the routing substrate  101 . As shown in more detail in  FIG.  12   , the socket connector housing  260  can include a side receptacle opening  265  for receiving a flexible circuit  240 . The cavity  272  can be exposed along a first side surface  122  of the first molding compound layer  120 , with the side receptacle openings  265  facing the cavity  272  opening in the first side surface  122 . In this manner, a flexible circuit  140  can extend into the cavity  272  from outside the first molding compound layer  120  and connect inside the side receptacle opening  265  of the socket connector housing  260 . 
     In accordance with embodiments, a shield can  270  can be located over the socket connector housing  260  and embedded within the first molding compound layer  120 . The shield can  270  can be electrically conductive (e.g. metal) or insulating, and may be bonded to the routing substrate  101  with a suitable adhesive material (including solder) to secure the shield can  270  on the routing substrate  101 . Prior to singulation the shield can  270  may completely laterally surround the socket connector housing  260  so as to prevent the influx of molding compound  120  during overmolding. As such, the cavity  272  may be defined by the shield can  270 , which can facilitate unabated access to the side receptacle opening  265  of the socket connector housing  260 . 
     The shield can  270  can be a separate component from the socket connector housing  260 , or a part of socket connector housing  260 . In the exemplary embodiment illustrated in  FIG.  11    and open space separates the top surface  264  of the socket connector housing a lid  274  of the shield can  270 . The lid  274  of the shield can  270  can also be directly on the top surface  264  (or form the top surface  264 ) of the socket connector housing  260 . A back side of the socket connector housing  260  (opposite the side receptacle opening  265 ) can be located close to or in contact with a sidewall of the shield can  270  for increased packing density of the SiP. Similarly, side surfaces of the socket connector housing  260  can be located close to or in contact with sidewalls of the shield can  270 . In some embodiments, the socket connector housing  260 , and entrance to the side receptacle opening  265  is laterally offset form the first side surface  122  of the first molding compound layer  120 . This may protect the socket connector housing  260 , for example, during singulation of the SiP  125 . 
     Following singulation of the SiP  125  to expose the cavity  272  and socket connector housing  260 , a flexible circuit  140  can be inserted into the side receptacle opening  265  and connected. For example, this may be achieved by a plurality of spring compression contacts on the flexible circuit  140  and/or within the socket connector housing  260 . In the embodiment illustrated in  FIG.  12    the socket connector housing  260  includes a plurality of spring compression contacts  262 , which can be located on a top side and/or bottom side of the side receptacle opening  265  to make contact with corresponding contacts  144  on the top and/or bottom sides of the flexible circuit  140 . It is to be appreciated that the location of spring compression contacts an alternatively, or additionally, located on the flexible circuit  140 . Alternatively, or in addition, various latches can be included within the socket connector housing  260  to help secure the flexible circuit  140  in place. In the illustrated embodiment an adhesive  280  can be applied around the flexible circuit  140  and adjacent the side receptacle opening  265  to secure the flexible circuit  140  inside the side receptacle opening  265 . 
     Referring again to  FIG.  11   , similar to previous descriptions an electronic component  141  may be mounted on the flexible circuit, which can be bent or folded around a side edge of the SiP  125 . The electronic component  141  may additionally be electrically connected to the routing substrate  101  via the socket connector housing  260 . The electronic component  141  can be a variety of components, such as a sensor that is oriented adjacent an opening  202  in a housing  200  of the electronic module  100 . 
       FIGS.  13 A- 13 D  are cross-sectional side view illustrations of method of forming an electronic module including socket connector housing for receiving a flexible circuit in accordance with an embodiment._Specifically, the process flow of  FIGS.  13 A- 13 C  can be used to fabricate the electronic module of  FIG.  11   . Initially the one or more electronic components  110 ,  111  and additional electronic components  112  are surface mounted on the routing substrate  101  as shown in  FIG.  13 A . In the illustrated embodiment, a socket connector housing  260  is mounted on the first side of the routing substrate  101 , followed by mounting a shield can  270  on the same side of the routing substrate  101  and over the socket connector housing  260 . While a single socket connector housing  260  and shield can  270  are illustrated, multiple socket connector housing and shield cans can be mounted on one or more sides of the routing substrate  101 . Furthermore, the shield can may be a portion of the socket connector housing. 
     One or both sides of the routing substrate  101  can then be overmolded (encapsulated) with molding compound layers  120 ,  160  as shown in  FIG.  13 B . As shown, the shield can  270  can prevent flow into the socket connector housing  260 . The molding compound layers, shield can  270 , and routing substrate can then be cut (e.g. singulation process) to expose side surfaces  122 ,  162  of the molding compound layers  120 ,  160  as well as side surfaces  279  of the shield can  270  and side surface  109  of the routing substrate  101  resulting in the structure illustrated in  FIG.  13 C , with exposed cavity  272  including the socket connector housing  260 . When singulating multiple SiPs from a reconstituted structure multiple socket connector housings  260  can be mounted within the same shield can  270  (with side receptacle opening  265  facing one another), and singulation can be performed between the socket connector housings  260 , thus utilizing a single shield can for multiple SiPs. A flexible circuit  140  can then be inserted through the cavity  272  in the first molding compound layer  120  and int the side receptacle opening  265  as shown in  FIG.  13 D . This may optionally be followed by application of an adhesive  280  around the flexible circuit  140  and adjacent the side receptacle opening  265  to secure the flexible circuit inside the side receptacle opening. In accordance with embodiments, the flexible circuit  140  may be inserted with minimal insertion force needed to compress the spring compression contacts or latches, and a separate actuator is not present on the socket connector housing  260  to retain contact. 
     Referring now to  FIGS.  14 A- 14 B  cross-sectional side view illustrations are provided for a method of forming an electronic module  100  including a 3D molded stack and button joints in accordance with an embodiment. The assembly process is similar to that illustrated and described with regard to  FIG.  6   , with a difference being that button joints are used to form vertical 3D stacked structures. As shown, the electronic module  100  includes an SiP  125  similar to those previously described herein. For example, the SiP  125  includes a routing substrate  101 , a first electronic component  110  mounted on a first side  102  of the routing substrate and encapsulated in a first molding compound layer  120 . The primary structural difference for the SiP  125  in  FIGS.  14 A- 14 B  is the inclusion of one or more vertical interconnects  195   5 bonded to the first side  102  of the routing substrate  101  (e.g. with solder) and encapsulated in the first molding compound layer  120 . Furthermore, a portion of the vertical interconnect  195  protrudes from a top exterior surface  126  of the first molding compound layer  120 . As shown an electronic assembly  300  can then be bonded to the vertical interconnect(s)  195  of the SiP  125  with a solder material. 
     In an embodiment, the electronic assembly  300  includes a circuit board  340  and a second electronic component  345  mounted on a first side  302  of the circuit board. Additional electronic components  312  may also be mounted on the first side  302  of the circuit board. A second side  304  of the circuit board  340  including landing pads  342  is bonded to the vertical interconnect(s)  195 . Similar to the description of  FIG.  6   , buttons  187  can be placed over the exposed vertical interconnects  195 , followed by optional dispensing of a solder paste  188 . Upon applying heat and pressure the buttons  187  and solder paste  188  can reflow to create a solder joint. 
     Such a configuration may allow for miniaturization without substantial changes at the system level. Furthermore the solderable buttons  187  can allow for fine pitch interconnection between molded assembly, with fine pitch of less than 300 μm. 
     In utilizing the various aspects of the embodiments, it would become apparent to one skilled in the art that combinations or variations of the above embodiments are possible for forming an electronic module. Although the embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the specific features or acts described. The specific features and acts disclosed are instead to be understood as embodiments of the claims useful for illustration.

Metadata:
Filing Date: 20220610
Publication Date: 20241119
Grant Date: 20241119
Priority Date: 20210820
Inventors: KANI, BILAL MOHAMED IBRAHIM
ERGUN, ALI N.
RENJAN, KISHORE N.
KIM, KYUSANG
VADEENTAVIDA, MANOJ
GRENA, BENJAMIN J.
KINDLON, DAVID M.
HOANG, LAN H.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01L23/315", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/592", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R43/205", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L21/56", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/62", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D11/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/6581", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/4985", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L25/165", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/3426", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K3/323", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/189", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/181", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/141", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/5387", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2225/06548", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L25/0657", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2223/6677", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L23/552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L2225/107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L25/165", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L25/16", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2225/1064", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L25/105", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/3121", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R12/79", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L25/162", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L25/162", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R43/205", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/6581", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/62", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/592", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L25/165", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/4985", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L23/315", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L21/56", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01D11/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L25/162", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 85229347