The present invention generally relates to semiconductor devices, and more specifically to interposers.
An RF module may include a die which is tuned by adjusting one or more properties of one or more passive devices. The passive devices may be discrete passive devices or components which are picked-and-placed on a printed circuit board. Following placement, the discrete passive devices may be soldered during reflow fabrication. The size of the discrete passive devices may be limited due to the pick-and-place fabrication and the reflow fabrication. In this regard, the machinery used to pick-and-place may include an accuracy at which the discrete passive device may be placed. Similarly, the machinery used to perform reflow fabrication may undesirably form bridges when the spacing between discrete passive devices is too small. Thus, a minimum spacing must be kept between the discrete passive devices to prevent accidental interconnection.
An important factor in the design of RF modules is size miniaturization. With 5G adoption and miniaturization trends, there is a need to reduce the dimensions of RF packages. Undesirably, the size of discrete passive devices is approaching a physical limit. In addition, due to footprint and spacing requirements, discrete passive components prohibit further package size reduction. However, such discrete passive devices may be indispensable to achieve the desired tuning of the die. Thus, the discrete passive devices may provide a limiting factor in reducing a size of the RF module. To integrate a die-based filter with a printed circuit board, the printed circuit board requires a large number of discrete passive devices. In some instances, the discrete passive devices may take up more space than the filter. Additionally, the discrete passive devices may not be placed on the printed circuit board under the die. Instead, the discrete passive devices are placed on the printed circuit board surrounding the die.
A package is disclosed, in accordance with one or more embodiments of the present disclosure. In one illustrative embodiment, the package includes a printed circuit board. In another illustrative embodiments, the package includes an interposer coupled to the printed circuit board. In another illustrative embodiment, the interposer includes a substrate including at least one via. In another illustrative embodiment, the interposer includes a multilayer structure disposed above the substrate. In another illustrative embodiment, the multilayer structure includes a top layer with an array including a plurality of passive devices integrated into at least one of the substrate or a dielectric of the multilayer structure. In another illustrative embodiment, the at least one via couples the plurality of passive devices to the printed circuit board. In another illustrative embodiment, the interposer includes a trace disposed above the multilayer structure and connecting at least one passive device of the plurality of passive devices to a pad disposed above the multilayer structure. In another illustrative embodiment, the array includes a property defined by the at least one passive device which is connected to the trace. In another illustrative embodiment, the package includes a die coupled to the pad.
An interposer is disclosed, in accordance with one or more embodiments of the present disclosure. In one illustrative embodiment, the interposer includes a substrate with at least one via. In another illustrative embodiment, the interposer includes a multilayer structure disposed above the substrate. In another illustrative embodiment, the multilayer structure includes a top layer with an array including a plurality of passive devices integrated into at least one of the substrate or a dielectric of the multilayer structure. In another illustrative embodiment, the at least one via couples the plurality of passive devices to a first pad on a bottom of the substrate by which the interposer is configured to couple to a printed circuit board. In another illustrative embodiment, the interposer includes a trace disposed above the multilayer structure and connecting at least one passive device of the plurality of passive devices to a second pad disposed above the multilayer structure by which the interposer is configured to couple to a die. In another illustrative embodiment, the array includes a property defined by the passive device which is connected to the trace.
A communication device is described, in accordance with one or more embodiments of the present disclosure. In one illustrative embodiment, the communication device includes a motherboard. In another illustrative embodiment, the communication device includes a radio frequency module. In another illustrative embodiment, the radio frequency module includes a printed circuit board coupled to the motherboard. In another illustrative embodiment, the radio frequency module includes an interposer coupled to the printed circuit board. In another illustrative embodiment, the interposer includes a substrate including at least one via. In another illustrative embodiment, the interposer includes a multilayer structure disposed above the substrate, the multilayer structure including a top layer with an array including a plurality of passive devices integrated into at least one of the substrate or a dielectric of the multilayer structure. In another illustrative embodiment, the at least one via couples the plurality of passive devices to the printed circuit board. In another illustrative embodiment, the interposer includes a trace disposed above the multilayer structure and connecting at least one passive device of the plurality of passive devices to a pad disposed above the multilayer structure. In another illustrative embodiment, the array includes a property defined by the passive device which is connected to the trace. In another illustrative embodiment, the radio frequency module includes a die coupled to the trace.
Implementations of the concepts disclosed herein may be better understood when consideration is given to the following detailed description thereof. Such description makes reference to the included drawings, which are not necessarily to scale, and in which some features may be exaggerated and some features may be omitted or may be represented schematically in the interest of clarity. Like reference numerals in the drawings may represent and refer to the same or similar element, feature, or function. In the drawings:
Before explaining one or more embodiments of the disclosure in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure that the embodiments disclosed herein may be practiced without some of these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the instant disclosure.
As used herein a letter following a reference numeral is intended to reference an embodiment of the feature or element that may be similar, but not necessarily identical, to a previously described element or feature bearing the same reference numeral (e.g., 1, 1a, 1b). Such shorthand notations are used for purposes of convenience only and should not be construed to limit the disclosure in any way unless expressly stated to the contrary.
Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of “a” or “an” may be employed to describe elements and components of embodiments disclosed herein. This is done merely for convenience and “a” and “an” are intended to include “one” or “at least one,” and the singular also includes the plural unless it is obvious that it is meant otherwise.
Finally, as used herein any reference to “one embodiment” or “some embodiments” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment disclosed herein. The appearances of the phrase “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment, and embodiments may include one or more of the features expressly described or inherently present herein, or any combination or sub-combination of two or more such features, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure.
Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings. Embodiments of the present disclosure are generally directed to providing an interposer with integrated passive devices, which may also be referred to herein as integrated passives, passive devices, or integrated passive components. As used herein, the term integrated, integrating, and the like may refer to forming a component (e.g., a passive component) in one or more portions of an appropriate device, such as a metal layer, a dielectric, a multilayer structure, a substrate, and the like of an interposer or any other device. Integrating the passive devices in the interposer may be advantageous to reduce an in-plane dimension of the package. Furthermore, an array of the integrated passive devices may be integrated into one or more layers of the interposer for access from a top layer of the interposer. By being accessible from the top layer of the interposer, a trace connecting the integrated passive devices to a pad may be formed during a masking step to achieve a desired property. The property may include, but is not limited to, a capacitance, a resistance, or an inductance. Thus, the die may be tuned without requiring a redesign of the interposer. Instead, the interposer may achieve the desired property by masking the trace in a different arrangement. The interposer may then be coupled to a die and a printed circuit board to form a package. For example, the package may include, but is not limited to, a radio frequency (RF) module, an RF front end, and the like. As used herein the terms “coupled”, “coupling”, “connected,” “connecting,” and the like may allow for intervening layers, devices, or structures, unless indicated otherwise (e.g., “directly coupled”).
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The package 100 may include multiple of the die 106 which are coupled to the interposer 104. The package 100 may also include one or more die 106 which are stacked on top of one another. Stacking the dies may reduce a footing requirement of the package 100. Furthermore, the package 100 may include any number of additional dies which may be coupled directly to the printed circuit board 102.
The die 106 may include, but is not limited to, a filter, a power amplifier, and the like. The package 100 may thus be used in a number of RF applications, such as, but not limited to, a radio frequency (RF) module of a mobile phone or another communication device. In such RF applications, designs of the package 100 may be sensitive to size and cost requirements. The die 106 may be electrically coupled to a number of passive devices to achieve a desired level of tuning. In embodiments, the interposer 104 includes passive devices 110 which are used to tune the die 106.
In embodiments, the interposer 104 includes one or more passive devices 110. The passive devices 110 are integrated with the interposer 104 during fabrication of the interposer. The interposer 104 may be fabricated using wafer-level technology. In this regard, the passive devices 110 may be integrated into one or more layers of a wafer. The wafer may then be cut to form the interposer 104. The passive devices 110 may be advantageous in reducing a size of the passive devices for the package 100, as compared to discrete passive components placed on the printed circuit board 102. Reducing the size of the passive devices 110 may be advantageous for reducing spacing requirements for tuning the die 106. By integrating the passive devices 110 in the interposer 104, the interposer 104 together with the integrated passive devices may also be placed under the die 106. This may be advantageous when compared to discrete passive components which may not be placed under the die 106 due to height constraints. Since the passives are integrated into the interposer, the clearance of the passive is no longer an issue. Additionally, the minimum distance between the integrated passive devices may be reduced, as compared to the use of discrete passive components, due to a reduced risk of the integrated passive devices accidentally interconnecting during fabrication of the metal layers. Placing the passive devices in the interposer 104 may thus reduce a footage requirement for the printed circuit board 102.
The passive devices 110 may include one or more of a resistor (e.g., thin-film resistor (TFR), etc.), a capacitor (e.g., metal-insulator-metal (MIM) capacitors, deep-trench capacitors (TC), metal-oxide-semiconductor (MOS) capacitor, metal fringe capacitors, etc.), or an inductor (e.g., a planar spiral inductor, etc.). As may be understood, the passive devices 110 may generally include any passive device which is suitable for integration into the interposer 104. Furthermore, the passive devices 110 may include any material, shape, and size for achieving the desired properties. The various passive devices described may be integrated into the interposer during one or more wafer fabrication steps. A property, such as, but not limited to, a resistance, a capacitance, or an inductance, may be selectively controlled based on the passive devices 110.
The interposer 104 may include the passive devices 110 without any active components (e.g., transistor, diodes, etc.) such that the interposer 104 is considered a passive interposer. The interposer 104 may then be connected to the die 106 which includes a number of passive and active components, such that the die 106 is considered an active die or an integrated circuit (IC) die.
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The passive devices 110 may be integrated into one or more of the substrate 202 and one or more layers of the multilayer structure 204. In embodiments, the passive devices 110 are integrated into a top layer of the multilayer structure 204. The passive devices 110 may be arranged on the top surface to form an array 210. Although not depicted, the vias 224, together with one or more metallization layers, may couple the passive devices 110 of the array 210 to the printed circuit board 102. As used herein, coupling by a via is not intended to be limited to a direct connection between the via and the associated component(s). For instance, the vias may connect to pads and subsequently the associated component(s). By way of another instance, multiple vias may be interconnected through traces and the like. The via may thus be coupled to the component(s) in any number of manners.
The array 210 may include a collection of the passive devices 110 which are grouped together on a top surface of the interposer 104. Any number of the integrated passive devices 110 may be formed in the array during a wafer processing step. Furthermore, multiple types of passive devices may be integrated into a same layer. The array 210 may generally include any suitable arrangement of the passive devices 110. For example, the array may be a rectangular array with a first number of the passive devices 110 along the width of the array and a second number of the passive devices 110 along the length of the array. It is further contemplated that other dimensional arrays may be suitable for the array 110, such that the recitation of rectangular array is not intended to be limiting. The size, position, and arrangement of the passive devices in the array is not intended to be limiting. The array 210 may be positioned in any number of positions on the top surface of the interposer 104. The interposer 104 may also include any number of the arrays 210. Furthermore, the passive devices 110 within the array 210 may include values (e.g., resistances, capacitances, inductances) which are substantially similar or may include values which are different. The passive devices 110 within the array 210 may also include one or more of resistances, inductances, and capacitances. As depicted, the resistors, inductors, and capacitors may be grouped into arrays which share a common resistance, inductance, or capacitance property, although this is not intended to be limiting. The resistors, inductors, and capacitors may also be grouped into arrays which do not share a common property. For example, any number of resistors, inductors, and capacitors may be grouped in the array 210 to achieve a property which includes a capacitance, resistance, and/or inductance.
One or more of the passive devices 110 of the array 210 may be connected by a trace 212. The trace 212 may be formed on the top layer by mask lithography, or a similar fabrication process. The trace 212 may include any trace material, such as, but not limited to, a copper trace. The trace 212 may connect the passive devices 110 to one or more pads 222 on which the die 106 is coupled. The trace 212 may include a series and/or a parallel connection between any number of the passive devices 110. The property of the array 210 may thus be set based on the arrangement of the trace 212 connecting the passive devices 110 in parallel and/or in series. To achieve the desired property, any number of the array 210 may be connected. The trace 212 may also connect to only a portion of the passive devices contained in the array 210. The remaining components of the array may then be left unused on the interposer.
The array 210 may also include a number of passive devices 110 which are not connected by the trace 212 (also referred to as connected out). The passive devices 110 which are not connected by the trace 212 may be provided to adjust the property of the array 210 in an additional mask fabrication without refabricating an underlying layer of the interposer 104. Thus, the passive devices 110 may be integrated into the interposer 104 and used to change the properties of the array 210 and subsequently for tuning the performance of the die 106. The ability to adjust the property of the array 210 is particularly beneficial in radio frequency (RF) applications, because in RF applications the properties may be adjusted to achieve an improved RF performance more rapidly without requiring a redesign and refabrication of the die 106. In this regard, RF applications may use iterative tuning which may be more rapidly accomplished by the use of the interposer 104 and changing the top mask of the interposer 104.
The passive devices 110 may be arranged to form one or more types of arrays, such as, but not limited to, an array 210a including one or more resistors, an array 210b including one or more capacitors, or an array 210c including one or more inductors. The array 210a may include one or more thin-film resistors 214, and the like. The array 210b may include one or more deep-trench capacitors 216, MIM capacitors 218, metal-oxide-semiconductor (MOS) capacitor, metal fringe capacitors, and the like. For example, the MIM capacitor 218 may include two metal plates (e.g., electrodes) each on a separate layer of the multilayer structure. The metal plates may be separated by a dielectric layer. The dielectric layer separating the metal plates may be formed of a material with a different dielectric constant than the dielectric 208 of the multilayer structure. The metal plates may be formed of the same material as the metal trace or a different material. Although the capacitor array is described as including MIM capacitors, this is not intended as a limitation of the present disclosure. By way of another example, the deep-trench capacitor 216 may include a trench with two sides of metal material (e.g., electrodes) filled by a dielectric material and extending between from the top layer through one or more lower layers. Thus, a trench may be formed in the substrate 202 with the two sides of metal material and the dielectric. The array 210c may include one or more inductors, such as planar spiral inductors 220, and the like. The inductors may be provided across one or more metal layers. For example, the inductor may include a two-dimensional coil structure or a three-dimensional coil structure. The three-dimensional coil structure may be provided across multiple metal layers which may be connected between the metal layers by vias. As may be understood, where the passive device 110 includes an inductor, the inductor may generally include any shape for generating an inductance value. Thus, the array 210a, the array 210b, and the array 210c may be provided for adjustable properties including resistance, capacitance, and inductance for the die 106.
Integrating the passive devices 110 into the top layer of the interposer 104 may be advantageous for reducing a package height. To reduce the package height, one or more of the passive devices 110 may be placed underneath the die 106. For example,
Although the passive devices 110 are described as being integrated into the top layer of the interposer 104, this is not intended as a limitation of the present disclosure. The multilayer structure 204 may also include any number of the passive devices 110 integrated into one or more lower layers of the multilayer structure 204 below the top layer and/or into the substrate 202. For example, the lower layers of the multilayer structure 204 may include a MIM capacitor, deep-trench capacitor, a thin film resistor, an inductor, or another passive device, which may be formed from one or more of the metal layers. Furthermore, the substrate 202 may include one or more of the passive devices 110. For example, the substrate 202 may include a deep trench capacitor, or another passive device. Where the passive devices 110 are provided below the top layer, such passive devices 110 may then be connected between the printed circuit board 102 and the die 106 for forming a circuit connection. For example, the passive devices 110 within the lower metallization layers and the substrate may be connected out during fabrication of the metallization layers.
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The printed circuit board 102 may include one or more metal layers separated by one or more insulating layers (not depicted). The metal layers may be formed from any electrically conductive material compatible with fabrication of printed circuit boards, such as, but not limited to, copper, gold, silver, aluminum, and the like. Similarly, the insulating layers may be formed by any electrically insulating material compatible with fabrication of printed circuit boards, such as, but not limited to, a resin material (e.g., FR-4), and the like. The metal layers may generally be fabricated by any printed circuit board fabrication process. The printed circuit board 102 may also include multiple layers of the metal layers and the insulating layers, such that the printed circuit board 102 may be considered a multilayer PCB.
The interposer 104 may fan out a pitch from the die 106 to the printed circuit board 102. Fanning out the pitch may be advantageous for connection purposes. In this regard, the die 106 may include contacts which have a much smaller pitch or size as compared to contacts of the printed circuit board 102. The interposer 104 may fan out the signal lines from a fine pitch to a coarse pitch in any manner known in the art. For example, the vias 224 may include, but are not limited to, through-silicon vias (TSV). The printed circuit board 102 may thus communicate various signals between the printed circuit board 102 and the die 106.
As may be understood, the various figures depicted herein are not drawn to scale but are merely provided for illustration. For example, the metallization layers of the interposer 104 may be layered at a ten micron to a hundred of micron scale. The scale of the metal layers may also decrease with changes in wafer fabrication technology. Furthermore, the scale of and the distance between the metal layers may be different across the layers. Furthermore, the various figures provided herein are merely illustrative of the various embodiments described herein.
It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. Furthermore, it is to be understood that the invention is defined by the appended claims.