Electromagnetic shields for sub-modules

Electromagnetic shields for sub-modules of electronic modules are disclosed. Electronic modules may include multiple sub-modules arranged on a substrate with an electromagnetic shield arranged to conformally cover the sub-modules as well as portions of the substrate that are uncovered by the sub-modules. Electromagnetic shields are disclosed that are configured to extend between sub-modules to form one or more divider walls. The one or more divider walls may be configured to extend below mounting surfaces of electronic components in the sub-modules to provide improved reduction of electromagnetic interference (EMI) or crosstalk between various sub-modules. Electromagnetic shields are also disclosed that form perimeter sidewalls that extend below mounting surfaces of electronic components of sub-modules to provide improved reduction of EMI from other modules or other external sources.

FIELD OF THE DISCLOSURE

The present disclosure relates to electromagnetic shields for electronic devices, and particularly to electromagnetic shields for sub-modules of electronic devices.

BACKGROUND

Electronic components have become ubiquitous in modern society. The electronics industry routinely announces accelerated clocking speeds and smaller integrated circuit modules. While the benefits of these devices are myriad, smaller and faster electronic devices create problems. In particular, high clock speeds inherently require fast transitions between signal levels. Fast transitions between signal levels create electromagnetic emissions throughout the electromagnetic spectrum. Such emissions are regulated by the Federal Communications Commission (FCC) and other regulatory agencies. Furthermore, fast speed transitions inherently mean higher frequencies. Higher frequencies mean shorter wavelengths, requiring shorter conductive elements to act as antennas to broadcast these electromagnetic emissions. The electromagnetic emissions radiate from a source and may impinge upon other electronic components. If the signal strength of the emission at the impinged upon electronic component is high enough, the emission may interfere with the operation of the impinged upon electronic component. This phenomenon is sometimes called electromagnetic interference (EMI) or crosstalk. Dealing with EMI and crosstalk is sometimes referred to as electromagnetic compatibility (EMC). Other components, such as transceiver modules, inherently have many radiating elements that raise EMI concerns. Thus, even electronic modules that do not have high clock speeds may need to address EMI issues.

One way to reduce EMI to comply with FCC regulations is to electromagnetically shield the electronic modules. Typically a shield is formed from a grounded conductive material that surrounds an electronic module. When electromagnetic emissions from the electronic module strike the interior surface of the conductive material, the electromagnetic emissions are electrically shorted through the grounded conductive material, thereby reducing emissions. Likewise, when emissions from another radiating element strike the exterior surface of the conductive material, a similar electrical short occurs, and the electronic module experiences reduced EMI from other electronic modules.

However, as electronic modules continue to become smaller from miniaturization, creating effective shields that do not materially add to the size of modules becomes more difficult. Thus, there is a need for an electromagnetic shield that is inexpensive to manufacture on a large scale, does not substantially increase the size of electronic modules, and effectively deals with EMI concerns.

SUMMARY

The present disclosure relates to electromagnetic shields for electronic devices, and particularly to electromagnetic shields for sub-modules of electronic modules. Electronic modules as disclosed herein may include multiple sub-modules arranged on a substrate with an electromagnetic shield arranged to conformally cover the sub-modules as well as portions of the substrate that are uncovered by the sub-modules. Electromagnetic shields are disclosed that are configured to extend between sub-modules to form one or more divider walls. In certain embodiments, the one or more divider walls are configured to extend into the substrate to provide improved reduction of electromagnetic interference (EMI) or crosstalk between the sub-modules. In certain embodiments, various electromagnetic shields may further form perimeter sidewalls that also extend into their corresponding substrates to provide improved reduction of EMI from other modules or other external sources.

In one aspect, an electronic module comprises: a substrate; a first sub-module and a second sub-module arranged on a mounting surface of the substrate; and an electromagnetic shield arranged on the first sub-module and the second sub-module, wherein a portion of the electromagnetic shield is configured to extend between the first sub-module and the second sub-module to form a divider wall that extends below the mounting surface. The substrate may comprise a plurality of metal layers and one or more dielectric layers. In certain embodiments, the portion of the electromagnetic shield that is between the first sub-module and the second sub-module is configured to extend through at least a portion of a first dielectric layer of the one or more dielectric layers. The first sub-module comprises one or more first electronic components within a first overmold body and the second sub-module comprises one or more second electronic components within a second overmold body. In certain embodiments, the electromagnetic shield is configured to be conformal with the first overmold body and the second overmold body. At least one of the one or more first electronic components may comprise a wirebond connection that at least partially extends into the first overmold body. In certain embodiments, the electromagnetic shield is conformal over the first sub-module, the second sub-module, and a portion of the mounting surface that is uncovered by the first sub-module and the second sub-module. In certain embodiments, the electromagnetic shield forms a perimeter sidewall that is configured to extend into a perimeter portion of the substrate. In certain embodiments, the perimeter sidewall may extend to a different horizontal plane within the substrate than the divider wall. In other embodiments, the perimeter sidewall extends to a same horizontal plane within the substrate as the divider wall. In certain embodiments, the electromagnetic shield forms a plurality of divider walls between the first sub-module and the second sub-module.

In another aspect, an electronic module comprises: a substrate; a first sub-module and a second sub-module arranged on a mounting surface of the substrate with an opening formed therebetween; an electromagnetic shield arranged on the first sub-module and the second sub-module, wherein a portion of the electromagnetic shield is configured to extend into the opening and along a portion of the substrate that is between the first sub-module and the second sub-module; and a fill material that is arranged on the portion of the electromagnetic shield that is in the opening. In certain embodiments, the fill material is configured to partially fill the opening. In certain embodiments, the fill material is configured to completely fill the opening. The fill material may comprise a conductive material. In certain embodiments, the first sub-module comprises one or more first electronic components within a first overmold body and the second sub-module comprises one or more second electronic components within a second overmold body. The fill material may comprise a same material as the first overmold body and the second overmold body. In certain embodiments, a plurality of openings are formed between the first sub-module and the second sub-module. In certain embodiments, the fill material at least partially fills the plurality of openings. In certain embodiments, the fill material is configured to extend below the mounting surface of the substrate.

In another aspect, a method comprises: mounting a plurality of electronic components to a mounting face of a substrate structure; depositing an overmold material to cover the plurality of electronic components; removing portions of the overmold material along a plurality of first separation lines that define a plurality of modules; removing portions of the overmold material along a plurality of second separation lines that at least partially define a plurality of sub-modules within each module of the plurality of modules, the removing along the plurality of second separation lines forming openings that are configured to extend below the mounting face; and depositing an electromagnetic shield to conformally coat the plurality of sub-modules and the openings. In certain embodiments, the method further comprises dicing the substrate structure to singulate the plurality of modules. In certain embodiments, each sub-module of the plurality of sub-modules comprises an overmold body and at least one electronic component of the plurality of electronic components. In certain embodiments, removing portions of the overmold material along the plurality of first separation lines and the plurality of second separation lines comprises at least one of cutting, drilling, or etching. In certain embodiments, a plurality of overmold bodies are formed by removing portions of the overmold material along the plurality of first separation lines and the plurality of second separation lines. In certain embodiments, depositing the electromagnetic shield comprises conformally coating the plurality of overmold bodies. The electromagnetic shield may form one or more divider walls between a first sub-module and a second sub-module of the plurality of sub-modules. In certain embodiments, the one or more divider walls may be configured to extend below the mounting surface of the substrate structure. In certain embodiments, depositing the electromagnetic shield comprises sequentially depositing a first seed layer, a second layer, and a third layer. In certain embodiments, the first seed layer is deposited by electroless plating, the second layer is deposited by electrolytic plating, and the third layer is deposited by electrolytic plating.

DETAILED DESCRIPTION

The present disclosure relates to electromagnetic shields for electronic devices, and particularly to electromagnetic shields for sub-modules of electronic modules. Electronic modules as disclosed herein may include multiple sub-modules arranged on a substrate with an electromagnetic shield arranged to conformally cover the sub-modules as well as portions of the substrate that are uncovered by the sub-modules. Electromagnetic shields are disclosed that are configured to extend between sub-modules to form one or more divider walls. In certain embodiments, the one or more divider walls are configured to extend into the substrate to provide improved reduction of electromagnetic interference (EMI) or crosstalk between the sub-modules. In certain embodiments, various electromagnetic shields may further form perimeter sidewalls that also extend into their corresponding substrates to provide improved reduction of EMI from other modules or other external sources.

The present invention may be used to form one or more electromagnetic shields for corresponding component areas of a given electronic module. In certain embodiments, a meta-module having circuitry for two or more modules is formed on a substrate structure, which may include a laminated substrate structure. As such, the circuitry for different modules is initially formed on the single meta-module. Each module will have one or more component areas in which the circuitry is formed. A metallic structure is formed on or in the substrate for each component area to be shielded on the substrate. The metallic structure may be formed from traces, vias, metallic layers, metallic components, plating materials, or the like, as well as any combination thereof. In one embodiment, each metallic structure extends about all or a portion of the periphery of each of the component areas to be shielded. A single body, such as an overmold body, is then formed over all of the modules on the meta-module. After the body is formed, at least a portion of the metallic structure for each component area to be shielded is exposed through the body by a cutting, drilling, or like operation. Next, an electromagnetic shield material is applied to an exterior surface of the body of each of the component areas to be shielded and in contact with the exposed portion of the metallic structures. The modules are then singulated from each other to form separate modules, each of which having one or more integrally shielded component areas.

In certain embodiments, the electromagnetic shield material is provided using an electroless plating process, which deposits a conductive seed layer on the overmold body and in contact with the exposed portions of the metallic structures. Then, an electrolytic plating process is used to deposit a second conductive layer onto the conductive seed layer. A final layer of a metallic material, such as nickel, is then deposited on top of the second conductive layer through an electrolytic plating process. In another embodiment, the electromagnetic shield is provided by applying a conductive epoxy or paint to the body and in contact with the exposed portion of the metallic structures. In other embodiments, the electromagnetic shield may be provided by metallized thin film-based processes, such as, for example physical vapor deposition, sputtering, evaporation, chemical vapor deposition, and/or atomic layer deposition, among others. In these embodiments, the conductive layers create an integrated electromagnetic shield for one or more component areas of a module to reduce electromagnetic interference (EMI).

For the following description, the preferred embodiments of the present invention are described. The scope of the invention and the claims that follow shall not be limited to these preferred embodiments. For example, the metallic structure in the preferred embodiments is formed in whole or in part from a metallic layer grid that resides on or in the surface of the substrate. Further, the metallic structure resides along all or a portion of the periphery of one or more component areas. These embodiments lend themselves to efficient processing; however, those skilled in the art will recognize that the metallic structure to which the integrated electromagnetic shield is connected need not reside along the periphery of the component area, or be part of a metallic layer grid. Importantly, the metallic structure may take virtually any form or shape, and may reside on or in the top surface of the substrate. The metallic structure may merely be a single point along the top surface of the module, as well as a continuous or segmented structure that extends along all or a portion of the one or more component areas to be shielded. Accordingly, the metallic layer grid used in the following embodiments to provide a metallic structure is merely provided to illustrate the preferred embodiments, and as such, shall not limit what constitutes a metallic structure or how a metallic structure is formed according to the present invention.

A module10is illustrated inFIG. 1AandFIG. 1Baccording to certain embodiments of the present invention. The module10has a substrate12, which may include a laminate structure that comprises a metallic structure formed from a metallic layer grid14on or in a top surface of the substrate12. In certain embodiments, the substrate12may comprise an epoxy laminate, such as FR-4 and the like. The substrate12may also be formed from other materials including ceramics and/or alumina. As indicated above, any metallic structure may be used; however, the preferred embodiment uses a portion of the metallic layer grid14to form a peripheral metallic structure. Only one section of the metallic layer grid14is depicted in these figures and the peripheral metallic structure is not separately labeled, as it is formed from the metallic layer grid14. The illustrated module10has a single component area16that lies within the peripheral metallic structure and in which circuitry for the module10is formed. The component area16may include one or more electronic components of various types depending on the application. For example, the electronic components may include an electronic circuit built on its own semiconductor substrate, such as a processor, volatile memory, non-volatile memory, a radio frequency circuit, or a micro-mechanical system (MEMS) device. In certain embodiments, electronic components may include one or more electrical devices such as filters, capacitors, inductors, resistors, amplifiers, low-noise amplifiers (LNA), switching devices, transmit/receive modules, or electronic circuits having combinations thereof. A body, such as an overmold body18or overmold material, which is formed from a dielectric material, resides over the substrate12and encompasses the component area16. As depicted inFIG. 1B, an electromagnetic shield20is integrally formed over the overmold body18and in contact with exposed portions of the peripheral metallic structure of the metallic layer grid14to provide shielding from electromagnetic emissions. In certain embodiments, the peripheral metallic structure of the metallic layer grid14is coupled to ground and accordingly, the electromagnetic shield20is electrically grounded. In this manner, electromagnetic emissions that strike the electromagnetic shield20are electrically shorted to ground, thereby reducing EMI.

A given module10may include any number of component areas16where one or more of the component areas16have a corresponding electromagnetic shield20. As illustrated inFIGS. 2A and 2B, two component areas16A and16B are positioned in the metallic layer grid14such that a peripheral metallic structure is provided for each of the component areas16A and16B. In certain instances, peripheral metallic structures for adjacent component areas16A and16B may share a common section of the metallic layer grid14.

The illustrated module10has two component areas16A and16B, which lie within corresponding peripheral metallic structures and in which circuitry (not illustrated) for the module10is formed. Overmold bodies18reside over the substrate12and encompass the respective component areas16A and16B. As depicted inFIG. 2B, one or more electromagnetic shields20are integrally formed over the overmold bodies18and in contact with exposed portions of the respective peripheral metallic structures of the metallic layer grid14. In particular, the one or more electromagnetic shields20encompass both component areas16A and16B and further extend between the component areas16A and16B. In the manner, EMI from outside sources and EMI between the component areas16A and16B may be reduced. Although the component areas16A and16B of the module10are illustrated as being adjacent one another, they may also be substantially separated from one another. In this manner, the module10is configured to include multiple sub-modules, each of which includes one of the component areas16A or16B as well as the corresponding overmold body18and the corresponding electromagnetic shield20or a portion of the electromagnetic shield20.

FIG. 3Ais a top view of a meta-module22at a certain state of fabrication according to embodiments disclosed herein. The meta-module22includes a plurality of components areas16A and16B mounted on a substrate12to form an array. Each of the component areas16A and16B are arranged to form a different area for a plurality of sub-modules24. One or more electronic components26as previously described may be mounted or otherwise arranged within each of the component areas16A and16B. The substrate12may comprise a strip or an otherwise larger form of a laminate structure. A plurality of fiducials28are arranged along a perimeter of the substrate12and outside of the plurality of sub-modules24. Fiducials28, or recognition marks, have many uses in the electronics industry, including the indication of mounting locations for various electronic components or to indicate the locations of separation lines for electronic components or electronic modules during fabrication. InFIG. 3A, the fiducials28are arranged to indicate the location of boundaries of each sub-module24. In other embodiments, groups of sub-modules24may form modules and the fiducials28may be arranged to indicate dicing lines for singulation of the modules.

FIG. 3Bis a top view of the meta-module22ofFIG. 3Aat a subsequent state of fabrication after an overmold material18has been applied to the component areas16A and16B. As illustrated, the overmold material18may be blanket deposited or otherwise formed over the substrate12to cover each of the component areas16A and16B. The overmold material18may comprise one or more insulating or dielectric materials. In this regard, the overmold material18may be configured to provide encapsulation and electrical isolation for the electronic components26that are mounted to the component areas16A and16B of the substrate12.

FIG. 3Cis a top view of the meta-module22ofFIG. 3Bat a subsequent state of fabrication where a plurality of overmold bodies18′ are formed from the overmold material18ofFIG. 3B. InFIG. 3C, a plurality of first separation lines30are illustrated that define locations where a plurality of modules32will later be divided or singulated from the meta-module22. A plurality of second separation lines34are illustrated that define locations for the sub-modules24within each of the modules32after singulation. For simplicity, only a few of the first separation lines30and the second separation lines34are illustrated. It is understood that in practice, the first separation lines30and the second separation lines34may be arranged across all of the meta-module22. The first separation lines30and the second separation lines34indicate lines where portions of the overmold material (18ofFIG. 3B) are subjected to a removal process. In certain embodiments, the removal process may include one or more of cutting, drilling, etching, or the like along each of the first separation lines30and the second separation lines34. In certain embodiments, the removal process may be referred to as sub-dicing as individual modules32are not yet separated from the meta-module22. Depending on the depth or amount of material to be removed, the removal process may be performed in one or more steps along the first separation lines30and the second separation lines34. For example, if the removal process is intended remove the same amount of material along each of the first separation lines30and the second separation lines34, then a sub-dicing process may be performed sequentially in rows and columns across the meta-module22that alternates between the first separation lines30and the second separation lines34. In another example, if the removal process is intended to remove differing amounts of material along each of the first separation lines30and the second separation lines34, then a first sub-dicing step may remove material along one of the first or second separation lines30,34, and a second sub-dicing step may remove material along the other of the first or second separation lines30,34. After the removal process is complete, each sub-module24includes one or more of the electronic components26and a separate overmold body18′ that is formed from the overmold material (18ofFIG. 3B). Additionally, openings that are formed along the first separation lines30and the second separation lines34may expose portions of the metallic layer grid (14ofFIG. 2B) that are electrically connected to ground. While two sub-modules24are illustrated for each module32, the first separation lines30and the second separation lines34may be configured in different locations to provide different numbers of sub-modules24for each module32according to embodiments disclosed herein. In certain embodiments, exposed surfaces of the overmold bodies18′ may be cleaned, such as by a plasma cleaning process, to remove wax or other organic compounds and materials that remain on the surface of each overmold body18′. The plasma cleaning process subjects the surface of each overmold body18′ to a reactive process gas, such as argon (Ar), oxygen (O), nitrogen (N), hydrogen (H), carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), nitrogen tri-fluoride (NF3), or the like, which effectively etches away contaminants on the exposed surface of each overmold body18′. In essence, the contaminants are vaporized, burned, or otherwise removed from the exposed surface of each overmold body18′ when exposed to the process gas. In certain embodiments, the cleaned surface of each overmold body18′ for each sub-module24may be roughened through an abrasion process, a desmear technique, or like process. In one embodiment, a chemical roughening process is provided. It should be appreciated that a mask (not shown) may be positioned on the underside of the substrate12so that the processes described in the steps below do not interfere with any electrical contacts (not shown) that may be present on the bottom side of each sub-module24. The mask helps prevent liquids and gases from reaching these electrical contacts, which may act as input/output contacts for the modules32. Alternatively, a seal structure may be employed.

FIG. 3Dis a top view of the meta-module22ofFIG. 3Cat a subsequent state of fabrication after the electromagnetic shield20has been blanket deposited over the sub-modules24. In certain embodiments, the electromagnetic shield20is deposited to conformally coat the plurality of sub-modules24. In particular, the electromagnetic shield20may be configured to be conformal on top surfaces and sidewalls of each overmold body18′ of each sub-module24as well as on portions of the substrate12that are between the sub-modules24. In certain embodiments, the electromagnetic shield20may be deposited as one or more layers of metal that are electrically grounded by way of exposed portions of the metallic layer grid (14ofFIG. 2B) between each of the overmold bodies18′. The electromagnetic shield20may comprise a single layer or a plurality of layers. In certain embodiments, the electromagnetic shield20may comprise a first layer comprising a seed layer followed by one or more additional layers. For example, the seed layer may comprise a conductive material such as copper (Cu), aluminum (Al), silver (Ag), gold (Au), or combinations thereof deposited by electroless plating or the like. A second layer may be subsequently formed on the seed layer comprising a metal such as Cu, Al, Ag, Au, or combinations thereof deposited by electrolytic plating or the like, followed by a third layer formed on the second layer, wherein the third layer comprises a less conductive material, such as nickel (Ni) or other metals, than the seed layer or the first layer. The third layer may also be formed by electrolytic plating. The third layer may be provided to protect the seed layer and the first layer from tarnishing, corrosion, or other environmental effects. Likewise, the third layer may contribute to shielding by absorbing some electromagnetic radiation. In an exemplary embodiment, the electromagnetic shield20may be formed with an approximate thickness in a range from about 10 microns (μm) to about 50 μm. Greater or lesser thicknesses may also be generated. For example, in certain embodiments, the thickness of the electromagnetic shield20may be reduced to a range from about 5 μm to about 10 μm. In certain embodiments, the electromagnetic shield20may be referred to as a microshield.

FIG. 3Eis a top view of two modules32that have been singulated from the meta-module22ofFIG. 3D. In certain embodiments, singulation includes dicing, sawing, or otherwise separating the substrate (12ofFIG. 3C) along the plurality of first separation lines (30ofFIG. 3C). In this manner, each module32may comprise a plurality of the sub-modules24, and each sub-module24may include one or more of the electronic components26and an overmold body18′. Each module32further includes an electromagnetic shield20that is arranged to cover each sub-module24as well as portions of the substrate12that are uncovered by each sub-module24. In this manner, each sub-module24is shielded from the other sub-module24as well as from external sources.

FIG. 4is a cross-sectional view of a representative module36according to embodiments disclosed herein. As illustrated, the module36includes a first sub-module24-1and a second sub-module24-2, although other numbers of sub-modules are possible without deviating from the present disclosure. As previously described, the first and second sub-modules24-1,24-2may each comprise one or more electronic components26mounted on the substrate12that are within a corresponding overmold body18′. The module36further includes the electromagnetic shield20that is conformal over each of the sub-modules24-1,24-2. In particular, the electromagnetic shield20conformally covers the overmold bodies18′ of each sub-module24-1,24-2as well as an opening38that is formed between the sub-modules24-1,24-2during the removal process of the overmold material (18ofFIG. 3B) performed along the second separation line34. As previously described, the substrate12may comprise a laminate structure that includes one or more metal layers40-1to40-3and one or more dielectric layers42-1to42-3. One or more vias43may also be provided to provide electrical connections between different ones of the metal layers40-1to40-3. In this regard, the substrate12may comprise a printed circuit board where the one or more metal layers40-1to40-3are laminated in an alternating configuration with the one or more dielectric layers42-1to42-3. While three metal layers40-1to40-3are illustrated, the substrate12may be configured with any number of metal layers. Generally, increasing the number of laminated metal layers corresponds to an increased number of electronic components that may be mounted and electrically connected on a particular laminate structure. This allows electrical connections to various electronic components26to be made at different horizontal planes within the substrate12. In certain embodiments, the one or more metal layers40-1to40-3may include Cu, copper foil, or the like while the one or more dielectric layers42-1to42-3may include fiber materials, glass, epoxy, glass-reinforced epoxy, ceramic materials, polymer materials and combinations thereof. Each of the metal layers40-1to40-3may comprise a pattern of continuous portions and discontinuous portions along the substrate12. As illustrated, certain ones of the electronic components26are mounted to different portions of the first metal layer40-1on a mounting surface44of the substrate12. In certain embodiments, one or more of the electronic components26may be flip-chip mounted on the mounting surface44. Notably, the opening38is configured to extend into the substrate12through the first metal layer40-1and the first dielectric layer42-1. In this regard, the electromagnetic shield20is arranged on the first sub-module24-1and the second sub-module24-2, and a portion of the electromagnetic shield20is configured to extend between the first sub-module24-1and the second sub-module24-2to form one or more divider walls20′ that extend below the mounting surface44. In particular, two divider walls20′ may be formed in the opening38where each of the divider walls20′ is conformal with one of the overmold bodies18′. By having a portion of the electromagnetic shield20extend below the mounting surface44where the electronic components26are mounted, the electronic components26may be further surrounded by the electromagnetic shield20to provide further reduction in EMI. InFIG. 4, the electromagnetic shield20is configured to extend through the first metal layer40-1and the first dielectric layer42-1to contact and electrically connect with a portion of the second metal layer40-2that is electrically connected to ground. As previously described, the opening38between the sub-modules24-1,24-2is formed by a removal process along the second separation line34. In certain embodiments, a width of the opening38measured as a distance from the first sub-module24-1to the second sub-module24-2may include a range from about 0.1 millimeters (mm) to about 3 mm, depending on the application and the removal process used to fabricate the opening38. For example, sawing with a saw blade of a particular width may provide an opening38with a width that is at least equal to the width of the saw blade.

FIG. 5is a cross-sectional view of an alternative configuration of the module36ofFIG. 4where one or more of the electronic components26comprise wirebond connections46. The module36includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. The wirebond connections46are configured to extend between corresponding ones of the electronic components26and corresponding portions of the first metal layer40-1. As illustrated, the wirebond connections46at least partially extend into the overmold bodies18′. In this regard, the wirebond connections46are formed prior to the overmold bodies18′ such that the overmold bodies18′ provide electrical insulation and mechanical support for the wirebond connections46. For cellphone handsets, wirebond connections46are often used in applications with higher power requirements. The wirebond connections46may provide electrical connection, thermal connection, or both between the electronic components26and the substrate12. In certain applications, the wirebond connections46can act as miniature antennas that facilitate undesirable leakage or interference of signals from the first sub-module24-1to the second sub-module24-2. As illustrated, the electromagnetic shield20including the divider walls20′ are arranged to reduce or prevent such crosstalk or EMI between the sub-modules24-1,24-2with the wirebond connections46. In certain embodiments, wirebond connections46and flip-chip mounting of different ones of the electronic components26may be provided in the same sub-module24-1,24-2or module36.

FIG. 6is a cross-sectional view of a module48where a perimeter sidewall20″ of the electromagnetic shield20is configured to extend into the substrate12according to embodiments disclosed herein. The module48includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. The overmold body18′ for each sub-module24-1,24-2is formed by the plurality of first separation lines30that define perimeter borders of the module48and the plurality of second separation lines34that define each of the sub-modules24-1,24-2. A portion of the electromagnetic shield20is configured to extend between the first sub-module24-1and the second sub-module24-2to form the one or more divider walls20′ that extend below the mounting surface44as previously described. In certain embodiments, the electromagnetic shield20forms one or more perimeter sidewalls20″ that surround the sub-modules24-1,24-2along a perimeter of the module48. Notably, at least one perimeter sidewall20″ is configured to extend into a perimeter portion of the substrate12. As previously described, the substrate12may comprise a laminate structure that includes the one or more metal layers40-1to40-3and the one or more dielectric layers42-1to42-3. In certain embodiments, at least one perimeter sidewall20″ of the electromagnetic shield20is configured to extend below the mounting surface44where the one or more electronic components26are mounted to the substrate12. As illustrated inFIG. 6, at least one of the perimeter sidewalls20″ is configured to extend through the first metal layer40-1, the first dielectric layer42-1, the second metal layer40-2, and the second dielectric layer42-2to contact a portion of the third metal layer40-3that is electrically connected to ground. In this manner, the perimeter sidewalls20″ are grounded such that electromagnetic emissions that strike the perimeter sidewalls20″ are electrically shorted to ground. By having one or more of the perimeter sidewalls20″ extend below the mounting surface44, the electronic components26may be further surrounded by the electromagnetic shield20to provide further reduction in EMI. In certain embodiments, one or more of the perimeter sidewalls20″ and one or more of the divider walls20′ are configured to extend below the mounting surface44. One or more of the perimeter sidewalls20″ and one or more of the divider walls20′ may be configured to extend to different horizontal planes within the substrate12depending on the application. InFIG. 6, the divider walls20′ are configured to extend to a horizontal plane defined by the second metal layer40-2while the perimeter sidewalls20″ are configured to extend to a different horizontal plane that is defined by the third metal layer40-3. In other embodiments, the different horizontal planes may be defined by different metal layers of the substrate12without deviating from the present disclosure.

FIG. 7is a cross-sectional view of a module50where one or more perimeter sidewalls20″ of the electromagnetic shield20extend below the mounting surface44of the substrate12, and one or more divider walls20′ of the electromagnetic shield20extend to the mounting surface44. The module50includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. Each of the sub-modules24-1,24-2may include one or more of the electronic components26that are mounted to the mounting surface44of the substrate12. The substrate12may comprise a laminate structure that includes the one or more metal layers40-1to40-3and the one or more dielectric layers42-1to42-3as previously described. In a similar manner toFIG. 6, one or more of the perimeter sidewalls20″ and one or more of the divider walls20′ ofFIG. 7are configured to extend to different horizontal planes of the substrate12. In particular, the perimeter sidewalls20″ are configured to extend through the first metal layer40-1, the first dielectric layer42-1, the second metal layer40-2, and the second dielectric layer42-2to contact a portion of the third metal layer40-3that is electrically connected to ground. The divider walls20′ are configured to extend between the sub-modules24-1,24-2to a portion of the first metal layer40-1that is at the mounting surface44of the substrate12. A portion of the first metal layer40-1in contact with the divider walls20′ may also be electrically connected to ground. In this manner, the divider walls20′ may not be configured to extend into the substrate12for certain applications.

FIG. 8is a cross-sectional view of a module52where one or more perimeter sidewalls20″ and one or more divider walls20′ of the electromagnetic shield20extend below the mounting surface44of the substrate12to the a same horizontal plane within the substrate12. The module52includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. Each of the sub-modules24-1,24-2may include one or more of the electronic components26that are mounted to the mounting surface44of the substrate12. The substrate12may comprise a laminate structure that includes the one or more metal layers40-1to40-3and the one or more dielectric layers42-1to42-3as previously described. InFIG. 8, the perimeter sidewalls20″ and the divider walls20′ are configured to extend through the first metal layer40-1, the first dielectric layer42-1, the second metal layer40-2, and the second dielectric layer42-2to contact portions of the third metal layer40-3that are electrically connected to ground. In this manner, the perimeter sidewalls20″ and the divider walls20′ may extend through the substrate12to a same horizontal plane that is within the substrate12. InFIG. 8, the same horizontal plane is defined by the third metal layer40-3. In other embodiments, the perimeter sidewalls20″ and the divider walls20′ may extend to a same horizontal plane that is defined by other metal layers (e.g.,40-2) of the substrate12.

FIG. 9is a cross-sectional view of a module54where a fill material56is applied in the opening38that is formed between the sub-modules24-1,24-2according to embodiments disclosed herein. The module54includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. Each of the sub-modules24-1,24-2may include one or more of the electronic components26that are mounted on the mounting surface44of the substrate12. As previously described, the electromagnetic shield20is arranged to conformally coat the overmold body18′ of each sub-module24-1,24-2as well as portions of the substrate12that are between and uncovered by the sub-modules24-1,24-2. In certain embodiments, the fill material56may be arranged in the opening38between each sub-module24-1,24-2to provide structural support. In this manner, the fill material56may be arranged on the portion of the electromagnetic shield20that is in the opening38and along one or more portions of the divider walls20′ of the electromagnetic shield20. In certain embodiments, the fill material56is configured to partially, but not fully fill the opening38and in other embodiments, the fill material56may completely fill the opening38. The fill material56may comprise one or more of an epoxy, a mold compound, and a thermoset material, among others. In certain embodiments, the fill material56comprises one or more insulating or dielectric materials. In certain embodiments, the fill material56may comprise the same material as the overmold bodies18′ of each sub-module24-1,24-2. The fill material56may be formed by dispensing, molding, transfer molding, or compression molding techniques, among others. In other embodiments, the fill material56may comprise a conductive material, such as conductive epoxy, or one or more metallized layers (not shown) formed by various plating or deposition techniques. In embodiments where the divider walls20′ of the electromagnetic shield20extend below the mounting surface44of the substrate12, the fill material56may also extend below the mounting surface44.

FIG. 10Ais a cross-sectional view of a module58where a plurality of openings38-1,38-2, as well as a plurality of divider walls20′-1to20′-4of the electromagnetic shield20are configured between the sub-modules24-1,24-2according to embodiments disclosed herein. The module58includes the first sub-module24-1and the second sub-module24-2on the substrate12, as well as the electromagnetic shield20as previously described. Each of the sub-modules24-1,24-2may include one or more of the electronic components26that are mounted on the mounting surface44of the substrate12. InFIG. 10A, the plurality of openings38-1,38-2are formed between the first sub-module24-1and the second sub-module24-2. The plurality of openings38-1,38-2may be formed by performing multiple removal processes that are adjacent to one another along the second separation line34. For example, a fabrication technique may comprise passing a narrow blade saw to cut two adjacent portions of the overmold material (18ofFIG. 3B) along the second separation line34between each of the sub-modules24-1,24-2. In this manner, the plurality of openings38-1,38-2are formed between the first and second sub-modules24-1,24-2. Additionally, another overmold body18″ may thereby be formed between the plurality of openings38-1,38-2and between the sub-modules24-1,24-2. After the plurality of openings38-1,38-2are formed, the electromagnetic shield20may be configured to conformally coat the overmold bodies18′ of each sub-module24-1,24-2as well as the overmold body18″ that is arranged between the sub-modules24-1,24-2. In this manner, the electromagnetic shield20may form the plurality of divider walls20′-1to20′-4between the sub-modules24-1,24-2. Accordingly, further reduction of crosstalk or EMI between sub-modules24-1,24-2may be provided. In certain embodiments, the plurality of divider walls20′-1to20′-4may extend into the substrate12and below the mounting surface44of the substrate12in any of the configurations previously described.

FIG. 10Bis a cross-sectional view of the module58ofFIG. 10Awhere the plurality of openings38-1to38-2are filled with the fill material56ofFIG. 9. As illustrated, the fill material56may be applied to partially or completely fill the plurality of openings38-1to38-2between each of the sub-modules24-1,24-2to provide structural support for the sub-modules24-1,24-2as well as the overmold body18″ that is arranged between the sub-modules24-1,24-2. In this manner, the fill material56may be arranged to partially or completely extend along each of the plurality of divider walls20′-1to20′-4of the electromagnetic shield20. For embodiments where the plurality of divider walls20′-1to20′-4extend into the substrate12and below the mounting surface44of the substrate12, the fill material56in each of the openings38-1,38-2may also extend below the mounting surface44.