Patent Application
20250087604
Embodiments of the subject matter described herein relate to structures and devices for coupling millimeter-wave signals generated by electronic devices to external antenna structures.
Miniaturized integrated circuits for millimeter-wave communications and other applications often must be coupled to antenna structures to function as intended. In some applications a launcher configured to couple millimeter-wave radiation is integrated in a device package or other assembly along with one or more millimeter-wave integrated circuits. In other applications, millimeter-wave integrated circuits are coupled to printed circuit boards that are provided with integrated millimeter-wave launchers that are designed to couple to millimeter-wave antenna structures.
In an example embodiment, a device assembly includes a first electronic device coupled to a carrier substrate, an enclosed cavity, an antenna structure, and an electrically conductive reflector within the enclosed cavity. The enclosed cavity has a first portion formed within the carrier substrate and a second portion formed within a volume of molding material. The antenna structure is electrically coupled to a first electronic device and disposed adjacent to the enclosed cavity and oriented toward an interior of the enclosed cavity. The electrically conductive reflector within the enclosed cavity is configured to direct electromagnetic signals toward or away from the antenna structure.
In another example embodiment, a method of forming a device assembly includes receiving a carrier substrate with a first open cavity. The carrier substrate has a first surface, a second surface opposite the first surface, and a first open cavity having electrically conductive walls. The first open cavity extending from the first surface of the carrier substrate toward the second surface. The method also includes disposing an electrically conductive structure that defines a second open cavity above the first open cavity; and bonding the conductive structure to the top surface of the carrier substrate such that the first open cavity forms a first portion of an enclosed cavity and the second open cavity forms a second portion of an enclosed cavity. The method also includes encapsulating the enclosed cavity within a volume of molding material disposed on the top surface of the carrier substrate. An antenna structure is electrically coupled to a first electronic device disposed on the carrier substrate and the antenna structure is disposed adjacent to the enclosed cavity and oriented toward an interior of the enclosed cavity. The enclosed cavity includes a conductive reflector that is configured to direct electromagnetic signals toward or away from the antenna structure.
The present disclosure is illustrated by way of examples, embodiments and the like and is not limited by the accompanying figures, in which like reference numbers indicate similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. The figures along with the detailed description are incorporated and form part of the specification and serve to further illustrate examples, embodiments and the like, and explain various principles and advantages, in accordance with the present disclosure, wherein:
The following detailed description provides examples for the purposes of understanding and is not intended to limit the invention or the application and uses of the same. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, or the following detailed description.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements or regions in the figures may be exaggerated relative to other elements or regions to help improve understanding of embodiments of the invention.
The terms “first,” “second,” “third,” “fourth” and the like in the description and the claims, if any, may be used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “comprise,” “include,” “have” and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or non-electrical manner. As used herein the terms “substantial” and “substantially” mean sufficient to accomplish the stated purpose in a practical manner and that minor imperfections, if any, are not significant for the stated purpose.
Directional references such as “top,” “bottom,” “left,” “right,” “above,” “below,” and so forth, unless otherwise stated, are not intended to require any preferred orientation and are made with reference to the orientation of the corresponding figure or figures for purposes of illustration.
Unless explicitly stated otherwise, the use of terms “approximately,” “substantially” and similar terms in connection with dimensions, relative positioning, or orientation of various features indicates that the dimensions, positioning, or orientation of those features are subject to tolerances and/or expected process variations of equipment and processes chosen to form the described features. Unless explicitly stated otherwise, the use of terms “approximately,” “substantially” and similar terms in connection measurable values or characteristics is subject to the expected measurement accuracy of equipment and methods used to measure those values or characteristics and/or within tolerance limits specified by technical standards applicable to the technologies described.
It will be appreciated that the steps of various processes described herein are non-limiting examples of suitable processes according to embodiments and are for the purposes of illustration. Embodiments herein may use any suitable processes including those that omit steps described herein, perform those steps and similar steps in different orders, and the like. It will also be appreciated that well-known features and techniques may be omitted for clarity.
It will be appreciated that although reference may be made to particular frequency ranges such as radio frequencies (“RF”), microwave frequencies (“MW”), and mm-Wave frequencies, that nothing herein is intended to limit embodiments to operation at any particular frequency range.
Miniaturization of radiofrequency and microwave electronics for generating and receiving wireless signals presents challenges because of the need for structures such as antennae to couple signals from packaged components (e.g., individual chips, systems on a chip, multichip packages, and the like) to free space. While it can be desirable to integrate such structures directly into a chip package doing so can significantly increase the package size because the minimum dimensions of an antenna and/or associated structures such as waveguides, transitions, and launchers are often comparable or significantly larger than the effective wavelength of the signals being transmitted. This can increase production costs and introduce undesirable geometric constraints on component placement within larger systems and devices. Some of these constraints are mitigated at higher frequencies such as the 30-300 GHz range (“millimeter waves”, having free-space wavelengths between 1-10 mm) because the of the reduced size requirements of components such as antennae and waveguides in the millimeter-wave regime compared to lower frequency regimes (e.g., in the MHz range and lower). However, integration of millimeter-wave launchers and other structures can still significantly increase minimum package sizes relative to the size of individual integrated circuits.
Accordingly, embodiments herein enable the integration of structures for wireless communications into molded device assemblies (or “packages”) while reducing overall package thickness when compared to other approaches. For example, the minimum package thickness required to include a reflecting cavity usable as a launcher for a millimeter-wave antenna structure can be reduced by forming a first portion of the cavity in a carrier substrate (e.g., a printed circuit board) and forming a second portion of the cavity within encapsulating material that forms the rest of a device package, as opposed to forming the cavity within only the substrate or within only the encapsulating material.
The package 100A includes an electronic device 105 bonded to the carrier substrate 110 (i.e., mechanically and electrically coupled to bond pads or similar structures patterned on or within the top surface of the layer 110c), an enclosed cavity 150, and an antenna structure 160 electrically coupled to the electronic device 105 that is configured to radiate or receive wireless signals. A volume of molding material 180 overlies the electronic device 105, the carrier substrate 110, and the enclosed cavity 150. In one or more embodiments, the enclosed cavity 150 may be filled with a dielectric material that is a solid, porous, and/or a gel material. In one or more such embodiments, the enclosed cavity is filled with a material having a dielectric constant that is lower than the dielectric constant(s) of the surrounding materials that form the carrier substrate 110 and the volume of molding material 180. It will be appreciated that the term “enclosed” is used herein to indicate that the enclosed cavity 150 is substantially surrounded by electrically conductive materials which confine and/or reflect electromagnetic signals within the cavity.
The enclosed cavity 150 has two portions. A first portion 150a is formed within the carrier substrate 110 as shown, while a second portion 150b extends above the carrier substrate 110 into the volume of molding material 180, as shown. In the example of
The second substrate 120 can be formed similarly to the carrier substrate 110 (e.g., another printed circuit board which is solder bonded or otherwise bonded to the carrier substrate 110). In the example of
An enclosed cavity such as the enclosed cavity 150 can be formed by bonding a substrate such as the substrate 120 to a carrier substrate such as the carrier substrate 110 using any suitable methods including soldering, sintering, bonding with conductive adhesive, or the like. As shown, in
A reflector such as the reflector 165 can be formed by depositing metal over a previously-formed cavity in a substrate such as the substrate 120. A reflector such as the reflector 165 can also be formed using existing techniques for forming conductive vias in printed circuit boards and conductive pads and traces on or within printed circuit boards, followed by selective removal of a portion of the substrate via etching, sawing, or any other suitable processes.
As shown, the antenna structure 160 is disposed opposite and adjacent to the ‘U’ shaped reflector 165. It will be appreciated that electromagnetic signals radiated from the antenna structure toward the reflector 165 will be reflected and redirected “downward” (i.e., toward the bottom of
For purposes of illustration, the electronic device 105 is depicted as a semiconductor device with conductive pillars 107 in
It will be understood that in
In the package 200A, the relative positions of the antenna structure 260 and the reflector 265 are reversed compared to the positions of the antenna structure 160 and the reflector 165 in the packages 100A, 100B. That is, the antenna structure 260 is disposed “over” the enclosed cavity 250 rather than “under” it (i.e., the antenna structure 260 is positioned directly adjacent to the second portion 250b of the enclosed cavity 250 rather than directly adjacent to the first portion 250a of the enclosed cavity 250). As illustrated by the wireless signal 299, the package 200A is configured such that electrical signals applied to the antenna structure 260 are directed “upward” as opposed to “downward” in the packages 100A, 100B.
It will be appreciated that, in one or more embodiments, a package includes multiple hollow cavities, each with a corresponding reflector and antenna structure and that each antenna structure (and the corresponding cavity and reflector) can be configured to direct wireless signals in either upward or downward directions perpendicular to the thickness of the package. It will also be appreciated that although antenna structures (and associated structures such as hollow cavities and conductive reflectors) may be described herein as radiating or directing signals in a particular direction that such structures can also be used to direct externally-generated wireless signals toward an antenna structure. For example, an antenna structure that is configured to direct signals “upward” or “downward” can also be said to be configured to receive signals propagating in the opposite direction.
It will be understood than an antenna structure according to embodiments herein (e.g., an antenna structure 160 or 260) can have any suitable design. For example, an antenna structure such as an antenna structure 160 or 260 may be configured as a dipole antenna, a folded dipole antenna, a patch antenna, or an array of one more types of antenna elements, as nonlimiting examples. Along these lines, it will be understood that the dimensions of hollow cavities such as the enclosed cavity 150 or the enclosed cavity 250 can be chosen to achieve desired performance characteristics which will depend on an intended operating frequency of a corresponding antenna structure. For example, it can be desirable for a distance between an antenna structure (e.g., an antenna structure 160 or 260) and a conductive reflector (e.g., a reflector 165 or 265) in the direction of signal propagation to be equal to one-fourth the signal wavelength within the enclosed cavity
where ∈r is the relative electric permittivity within the cavity (i.e., 1 for vacuum) As an example, the height of an enclosed cavity intended for use at a signal frequency of 77 GHz, can be as small as approximately 1 millimeter if the cavity is filled with air having a dielectric constant close to 1 and smaller if the cavity is filled with a dielectric material with a larger dielectric constant.
At step 310, the carrier substrate 110 is received with the antenna structure 160 and the interconnect 108 formed as shown using any suitable techniques including well-known printed circuit board manufacturing methods The metal features 312 on the substrate 110 will form part of the reflector 165 as described below. At step 320, the first portion 150a of the enclosed cavity 150 is formed in the carrier substrate 110 by selectively removing the portions of the substrate 110 between the locations indicated by the arrows 312. For example, in one or more embodiments, the interconnect 108, the antenna structure 160, and the conductive features that will form part of the reflector 165 are formed as conductive surface traces and conductive vias of the carrier substrate 110, followed by selective removal of layers of the carrier substrate 110 to expose the first portion 150a of the enclosed cavity 150. Meanwhile, in one or more other embodiments, the carrier substrate 110 is selectively patterned to form the first portion 150a of the enclosed cavity 150 before formation of the antenna structure 160 and/or the portions of the reflector 165 disposed within the first portion 150a of the enclosed cavity 150. In one more such embodiments, all or part of the reflector 165 in the first portion 150a of the enclosed cavity 150 is formed by metallization of the exposed cavity (i.e., at step 320 or after step 320).
The first portion 150a of the enclosed cavity 150 may be formed using any suitable processes. For example, a lithographic process in which a masking material (e.g., photoresist) is patterned on the carrier substrate 110 and exposed portions of the carrier substrate 110 are selectively removed with one or more etchants, followed by a plating process may be used. In another example, all or part of the reflector 165 within the carrier substrate 110 can be formed via processes used for creation of vias, followed by removal of the portions of the carrier substrate 110 surrounded by the reflector 165 to form the first portion 150a of the enclosed cavity 150.
In the example process 300 as depicted in
At step 330, the structure forming the second portion 150b of the enclosed cavity 150 (e.g., the second substrate 120) is bonded to the carrier substrate 110 forming the first portion 150a of the enclosed cavity 150. In the example of
It will be appreciated that the example process 300 or similar processes can be used to form packages according to embodiments herein such as the packages 100B, 200A, or 200B. For example, the package 100B can be formed using the process 300 by replacing the second substrate 120 with the conductive structure 130. Similarly, the package 200A can be formed using the process 300 by altering the locations of the conductive material forming the reflector 165, the antenna structure 160, and the electrical interconnect 108, and related structures to instead form the reflector 265, the antenna structure 260, and the electrical interconnect 208 of the package 200A. Similarly, the package 200B can be formed by replacing the additional substrate 220 with the conductive structure 230.
It will be further appreciated that embodiments herein are not limited to the “horizontally” oriented antennae 160, 260 (i.e., antennae with vertically-oriented radiation directions). Accordingly,
In the package 400, the relative positions of the antenna structure 460 and the reflector 465 are rotated compared to the positions of the antenna structure 160 and the reflector 165 in the packages 100A, 100B. That is, the antenna structure 460 is disposed along a vertical sidewall of the enclosed cavity 450 rather than “under” or “over” the enclosed cavity 450 and, as illustrated by the wireless signal 499, the package 400 is configured such that electrical signals applied to the antenna structure 460 are directed “sideways” as opposed to “downward” in the packages 100A, 100B or “upward” in the packages 200A, 200B.
In the example of
As above, it will be appreciated that various features are not drawn to scale. For example, the size of the solder bumps 490 are exaggerated in
It will also be appreciated that, in some embodiments, an antenna structure such as the antenna structure 460 (or an antenna structure 160 or 260 may differ from the structures shown and can include any suitable antenna structures. For instance, an antenna structures according to embodiments herein can include segmented antenna structures with more than one connection point or multiple segments (e.g., folded dipole antenna structures or segmented loop antenna structures), nonlimiting examples. Antenna structures according to embodiments herein can also include, as further non-limiting examples, antenna structures that include additional conductive elements such as ground planes (e.g., microstrip-based antenna structures or strapline-based antenna structures) and the like.
It will also be appreciated that the routing of an interconnect such as the interconnect 408 may take different paths than the one shown in
Features of embodiments may be understood by way of one or more of the following examples:
Example 1: A method or device that includes a first electronic device coupled to a carrier substrate, an enclosed cavity, an antenna structure, and an electrically conductive reflector within the enclosed cavity. The enclosed cavity has a first portion formed within the carrier substrate and a second portion formed within a volume of molding material. The antenna structure is electrically coupled to a first electronic device and disposed adjacent to the enclosed cavity and oriented toward an interior of the enclosed cavity. The electrically conductive reflector within the enclosed cavity is configured to direct electromagnetic signals toward or away from the antenna structure.
Example 2: The device or method of Example 1 that also includes an aperture in the carrier substrate that forms an open path between the interior of the enclosed cavity and an external environment surrounding the device.
Example 3: The device or method of Example 1 or Example 2, where electrically conductive reflector is formed by electrically conductive material lining the enclosed cavity and oriented opposite the antenna structure.
Example 4: The device or method of any of Examples 1-3, where the electrically conductive material is configured to reflect electromagnetic signals toward the antenna structure.
Example 5: The device or method of Examples 1-4 where the electrically conductive material lining the enclosed cavity includes a first section disposed within the first portion of the enclosed cavity and a second section disposed within the second portion of the enclosed cavity that is electrically contiguous with the first section.
Example 6: The device or method of Examples 1, that also includes an additional substate bonded to a first surface of the carrier substrate. The second portion of the enclosed cavity is formed within a cavity within the additional substate; and the additional substate is encapsulated within the volume of molding material.
Example 7: The device or method of any of Examples 1-6, where the antenna structure is formed by a conductive trace on or within an additional substrate. The antenna structure is separated from the electrically-conductive material in the second portion of the enclosed cavity by a layer of electrically-insulating material that forms part of the additional substrate.
Example 8: The device or method of any of Examples 1-7, where the antenna structure is disposed within the volume of molding material and is immediately adjacent to the second portion of the enclosed cavity.
Example 9: The device or method of any of Examples 1-7, where the antenna structure is disposed within the carrier substrate and is immediately adjacent to the first portion of the enclosed cavity.
The preceding detailed description and examples are merely illustrative in nature and are not intended to limit the embodiments of the subject matter or the application and uses of such embodiments. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no Intention to be bound by any expressed or implied theory presented in the preceding technical field, background, or detailed description.
It should be understood that this invention is not limited in its application to the details of construction and the arrangement of components set forth in the preceding description or illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The preceding discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The preceding detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The Figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.
The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in one or more embodiments of the subject matter. In addition, certain terminology may also be used herein for the purpose of reference only, and thus are not intended to be limiting, and the terms “first,” “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context.
The foregoing description refers to elements or nodes or features being “connected” or “coupled” together. As used herein, unless expressly stated otherwise, “connected” means that one element is directly joined to (or directly communicates with) another element, and not necessarily mechanically. Likewise, unless expressly stated otherwise, “coupled” means that one element is directly or indirectly joined to (or directly or indirectly communicates with, electrically or otherwise) another element, and not necessarily mechanically. Thus, although the schematic shown in the figures depict one exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in one or more embodiments of the depicted subject matter.
