PATENT DOCUMENT

Publication Number: US-11765838-B2
Application Number: US-202117407670-A
Country: US
Kind Code: B2

Title: Right angle sidewall 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; 
 a first lateral interconnect bonded to the first side of the routing substrate, wherein the first lateral interconnect extends through and is encapsulated in the first molding compound layer, and is exposed along a first side surface of the first molding compound layer; and 
 
 a flexible circuit mounted on the first side surface of the first molding compound layer, wherein 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. 
 
     
     
       2. The electronic module of  claim 1 , wherein the system-in-package further includes:
 a second electronic component mounted on a second side of the routing substrate and encapsulated in a second molding compound layer; and 
 a second lateral interconnect bonded to the second side of the routing substrate, encapsulated in the second molding compound layer, and exposed along a second side surface of the second molding compound layer. 
 
     
     
       3. The electronic module of  claim 2 , wherein the flexible circuit is mounted on the second side surface of the second molding compound layer, wherein a second landing pad of the flexible circuit is in electrical contact with the second lateral interconnect exposed along the second side surface of the second molding compound layer. 
     
     
       4. The electronic module of  claim 1 , wherein the first lateral interconnect comprises a metal pin or wirebond wire. 
     
     
       5. The electronic module of  claim 4 , wherein the first lateral interconnect has a maximum width of 25-75 μm where exposed along the first side surface of the first molding compound layer. 
     
     
       6. The electronic module of  claim 4 , wherein the first lateral interconnect has a maximum width of 250-500 μm where exposed along the first side surface of the first molding compound layer. 
     
     
       7. The electronic module of  claim 1 , wherein the first lateral interconnect comprises a metal stud bump. 
     
     
       8. The electronic module of  claim 1 , wherein the first lateral interconnect comprises a solder bump. 
     
     
       9. The electronic module of  claim 1 , wherein the flexible circuit is mounted on the first side surface of the first molding compound layer with a cured anisotropic conductive film. 
     
     
       10. The electronic module of  claim 1 , wherein the flexible circuit is mounted on the first side surface of the first molding compound layer with a cured self-alignment paste. 
     
     
       11. The electronic module of  claim 1 , wherein the flexible circuit is mounted on the first side surface of the first molding compound layer with a solder bump. 
     
     
       12. The electronic module of  claim 1 , wherein the first lateral interconnect protrudes from first side surface of the first molding compound layer. 
     
     
       13. The electronic module of  claim 12 , further comprising a solder material bonding the first lateral interconnect to the flexible circuit. 
     
     
       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 integrated 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:
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, 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 forma 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. 
         FIGS.  11 A- 11 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 a 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 naphthalate, 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 maybe 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 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 , 160  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 , 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 . 
     Referring now to  FIGS.  11 A- 11 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.  11 A- 11 B  is the inclusion of one or more vertical interconnects  195  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: 20210820
Publication Date: 20230919
Grant Date: 20230919
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
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Family ID: 85227715