High performance inductors

Disclosed is an inductor device including a first curved metal plate, a second curved metal plate below and substantially vertically aligned with the first curved metal plate, and a first elongated via vertically aligned between the first curved metal plate and the second curved metal plate, the first elongated via configured to conductively couple the first curved metal plate to the second curved metal plate and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

FIELD OF DISCLOSURE

This disclosure relates generally to inductors and more specifically, but not exclusively, to spiral inductors.

BACKGROUND

Inductors are ubiquitous passive analog electronic components that are used in a myriad of power regulation, frequency control, and signal conditioning applications in a range of devices including personal computers, tablet computers, wireless mobile handsets, etc.

Conventional spiral inductors include a top metal layer, a bottom metal layer, and a via connecting the top metal layer to the bottom metal layer. The via allows the induced current to flow from the top metal layer to the bottom metal layer. Such a via is typically in the shape of a cylinder, a square, an octagon, or a downwardly tapered trapezoid, and the effective diameter of the via limits the performance of the inductor by, for example, increasing the resistance of the inductor. That is, the via's resistance limits the inductor's quality factor (also referred to as the Q-factor or simply “Q”).

Inductors can be used in many applications, one being in a power amplification (PA) circuit for a semiconductor device. In such an implementation, the top metal layer is formed on the top of a substrate (e.g., an organic laminate substrate) and the via extends through the substrate to a metal layer beneath the substrate (i.e., the bottom metal layer).

SUMMARY

The following presents a simplified summary relating to one or more aspects and/or examples associated with the apparatus and methods disclosed herein. As such, the following summary should not be considered an extensive overview relating to all contemplated aspects and/or examples, nor should the following summary be regarded to identify key or critical elements relating to all contemplated aspects and/or examples or to delineate the scope associated with any particular aspect and/or example. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects and/or examples relating to the apparatus and methods disclosed herein in a simplified form to precede the detailed description presented below.

An inductor device includes a first curved metal plate, a second curved metal plate below and substantially vertically aligned with the first curved metal plate, and a first elongated via vertically aligned between the first curved metal plate and the second curved metal plate, the first elongated via configured to conductively couple the first curved metal plate to the second curved metal plate and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

A method of forming an inductor device includes forming a first curved metal plate, forming a second curved metal plate below and substantially vertically aligned with the first curved metal plate, and forming a first elongated via vertically aligned between the first curved metal plate and the second curved metal plate, the first elongated via configured to conductively couple the first curved metal plate to the second curved metal plate and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

An inductor device includes a first conductive means, a second conductive means below and substantially vertically aligned with the first conductive means, and a first elongated via vertically aligned between the first conductive means and the second conductive means, the first elongated via configured to conductively couple the first conductive means to the second conductive means and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

A non-transitory computer-readable medium storing computer executable code, includes code to cause a machine to form a first curved metal plate, cause a machine to form a second curved metal plate below and substantially vertically aligned with the first curved metal plate, and cause a machine to form a first elongated via vertically aligned between the first curved metal plate and the second curved metal plate, the first elongated via configured to conductively couple the first curved metal plate to the second curved metal plate and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

Other features and advantages associated with the apparatus and methods disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description.

In accordance with common practice, the features depicted by the drawings may not be drawn to scale. Accordingly, the dimensions of the depicted features may be arbitrarily expanded or reduced for clarity. In accordance with common practice, some of the drawings are simplified for clarity. Thus, the drawings may not depict all components of a particular apparatus or method. Further, like reference numerals denote like features throughout the specification and drawings.

DETAILED DESCRIPTION

Disclosed is an inductor device including a first curved metal plate, a second curved metal plate below and substantially vertically aligned with the first curved metal plate, and a first elongated via vertically aligned between the first curved metal plate and the second curved metal plate, the first elongated via configured to conductively couple the first curved metal plate to the second curved metal plate and having an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1.

These and other aspects of the disclosure are disclosed in the following description and related drawings directed to specific embodiments of the disclosure. Alternate embodiments may be devised without departing from the scope of the disclosure. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

The words “exemplary” and/or “example” are used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” and/or “example” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term “embodiments of the disclosure” does not require that all embodiments of the disclosure include the discussed feature, advantage or mode of operation.

FIGS. 1A and 1Billustrate an exemplary conventional inductor100. As shown inFIG. 1A, the inductor100may include a first curved metal plate110(e.g., a top metal layer, also referred to as a “trace”), a second curved metal plate120(e.g., a bottom metal layer, also referred to as a “trace”) substantially co-located below the first curved metal plate110, and a cylindrical via130between the first curved metal plate110and the second curved metal plate120. The via130conductively couples the first curved metal plate110to the second curved metal plate120through an insulating layer (not shown inFIG. 1A). The first curved metal plate110may include a first terminal112at one end, and the second curved metal plate120may include a second terminal122at one end. The first terminal112and the second terminal122may be configured to connect to external components for input and output of current through the inductor100.

FIG. 1Bshows a side view100A and a top view100B of the inductor100inFIG. 1A. As shown inFIG. 1B, an induced current132may traverse the inductor100from the first curved metal plate110through the via130to the second curved metal plate120and vice versa. The via130may be drilled or cut through an insulating layer140of a coreless substrate of a semiconductor device, and therefore have a height of approximately 40 μm. The first curved metal plate110may be on “top” of the insulating layer140and the second curved metal plate120may be on the “bottom” of the insulating layer140. A “coreless” substrate for a semiconductor device means that the semiconductor device does not include the “core” insulating layers that increase the rigidity of the semiconductor device. This allows the coreless substrate to be much thinner than a “buildup” substrate, which includes these core insulating layers. For example, a semiconductor device utilizing a coreless substrate may be approximately 430 μm thick, while a semiconductor device utilizing a buildup substrate may be approximately 1,150 μm due to the additional core layers.

AlthoughFIG. 1Billustrates the via130in the shape of a cylinder, the via130may be shaped as a square, an octagon, or a downwardly tapered trapezoid, as is known in the art. The effective diameter of the via130limits the performance of the inductor100, insofar as the resistance of the via130is inversely proportional to the area of the via130. Thus, the resistance of the via130adds to the resistance of the inductor100and thereby limits the Q-factor of the inductor100.

Accordingly, the present disclosure provides a two layer inductor that includes an elongated via between the top metal layer and the bottom metal layer of the inductor. This configuration may result in a high-performance radio frequency (RF) inductor implementation, such as in a coreless substrate, that improves power amplification (PA) performance by reducing loss in the inductor by approximately 7.25%, or as much as 10%, with no manufacturing process change and minimal area increase (e.g., 2.3%). In other examples, a spiral inductor may include a first metal layer, a second metal layer, and a third metal layer co-located on a substrate, where the second metal layer acts as a transition via between the first metal layer and the third metal layer. This configuration may result in low-resistance for the direct current (DC) for less heat dissipation and higher Q-factor performance at low frequencies and radio frequencies. These advantages are achieved by integrating such a high-performance inductor within a coreless substrate, along with the increased metal of the second metal layer providing a higher thermal conductance through the inductor.

FIGS. 2A and 2Billustrate an exemplary inductor200in accordance with some examples of the disclosure. As shown inFIG. 2A, the inductor200may include a first curved metal plate210(e.g., a “top” metal layer, also referred to as a “trace”), a second curved metal plate220(e.g., a “bottom” metal layer, also referred to as a “trace”) substantially co-located below and parallel to the first curved metal plate210, and an elongated via230between the first curved metal plate210and the second curved metal plate220. The elongated via230conductively couples the first curved metal plate210to the second curved metal plate220through an insulating layer (not shown inFIG. 2A). The first curved metal plate210may include a first terminal212at one end, and the second curved metal plate220may include a second terminal222at one end. The first terminal212and the second terminal222may be configured to connect to external components for input and output of current through the inductor200.

FIG. 2Bshows a side view200A and a top view200B of the inductor200. As shown inFIG. 2B, an induced current232may traverse the inductor200from the first curved metal plate210through the elongated via230to the second curved metal plate220and vice versa. The elongated via230may be drilled or cut through an insulating layer240of a coreless substrate of a semiconductor device. The first curved metal plate210may be on “top” of the insulating layer240and the second curved metal plate220may be on the “bottom” of the insulating layer240.

As illustrated inFIGS. 2A and 2B, the elongated via230may substantially follow the curve of and be narrower than the first curved metal plate210and the second curved metal plate220. The elongated via230may provide a longer and flatter transition between the first curved metal plate210and the second curved metal plate220for the induced current232. The elongated via230may have an aspect ratio of width-to-height of approximately 2-to-1 (2:1) or larger. As shown inFIG. 2B, the “width” (also referred to as the “length”) of the elongated via230is the dimension of the elongated via230along the curve (substantially parallel to the inside and outside edges) of the first and second curved metal plates210and220. The “height” of the elongated via230is the dimension of the elongated via230between the first and second curved metal plates210and220. The depth of the elongated via230is the dimension of the elongated via230between (substantially perpendicular to) the inside and outside edges of the first and second curved metal plates210and220.

Thus, unlike the induced current132having to make a high-resistance 90 degree bend to traverse the via130from the first curved metal plate110to the second curved metal plate120, as in the inductor100, the induced current232follows a longer, flatter, and therefore lower resistance path as it traverses the elongated via230from the first curved metal plate210and through to the second curved metal plate220. As an example, where the thickness of the insulating layer240is approximately 40 μm, the height of the elongated via230may be approximately 40 μm and the width of the elongated via230may be approximately 80 μm.

Note that althoughFIGS. 2A and 2Billustrate the inductor200as having a circular shape, it will be appreciated that the inductor200may have other shapes, such as an octagonal shape.

The insulating layer240may be one or more layers of silicon dioxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (SiON), tantalum pentoxide (Ta2O5), aluminum oxide (Al2O3), hafnium oxide (HfO2), benzocyclobutene (BCB), polyimide (PI), polybenzoxazoles (PBO), or other material having similar insulating and structural properties, as is known in the art. The first curved metal plate210, the second curved metal plate220, and the elongated via230may be one or more layers of aluminum (Al), copper (Cu), tin (Sn), nickel (Ni), gold (Au), silver (Ag), or other suitable electrically conductive material, as is known in the art.

The configuration of the inductor200results in a lower DC resistance and a higher Q-factor for the inductor200. For example, the Q-factor of the inductor200may be 131.6 at 1 GHz, whereas the Q-factor of the inductor100may be 122.7 at 1 GHz. The configuration of the inductor200may further result in a high-performance RF inductor implementation that improves PA performance by reducing loss in the inductor200by approximately 7.25%, or as much as 10%, with no manufacturing process change and minimal area increase on the insulating layer240(e.g., 2.3%).

FIG. 3illustrates an exemplary conventional spiral inductor300. As shown inFIG. 3, the spiral inductor300may include a spiral metal plate310. The spiral metal plate310may include a first terminal312at one end conductively coupled to an interconnect320and a second terminal322at the other end. The first terminal312, via the interconnect320, and the second terminal322may be configured to connect to external components for input and output of current through the spiral inductor300. For example, a current may enter the spiral inductor300at the first terminal312via the interconnect320, travel along the spiral metal plate310, and exit the spiral inductor300at the second terminal322. Alternatively, current may travel the same path in the opposite direction.

FIG. 4illustrates an exemplary stacked co-spiral inductor400in accordance with some examples of the disclosure. As shown inFIG. 4, the stacked co-spiral inductor400may include a first curved metal plate410, a second curved metal plate420substantially co-located below the first curved metal plate410, and a third curved metal plate430co-located between the first curved metal plate410and the second curved metal plate420. As illustrated inFIG. 4, each of the first curved metal plate410, the second curved metal plate420, and the third curved metal plate430may consist of multiple layers of metal. For example, each curved metal layer may consist of top and bottom metal layers connected by a middle metal layer.

The third curved metal plate430may be configured to conductively couple the first curved metal plate410to the second curved metal plate420. The first curved metal plate410may include a first terminal412at one end and a first via414at the other end. The second curved metal plate420may include a second terminal422at one end and a second via424at the other end. The first terminal412and the second terminal422may be configured to connect to external components for input and output of current through the stacked co-spiral inductor400.

The first via414may be configured to directly couple the first curved metal plate410to the third curved metal plate430. The second via424may be configured to directly couple the second curved metal plate420to the third curved metal plate430. For example, a current may enter the stacked co-spiral inductor400at the first terminal412, travel along the first curved metal plate410to the first via414, then from the first via414through the third curved metal plate430to the second via424, and from the second via424through the second curved metal plate420to the second terminal422to exit the stacked co-spiral inductor400. Alternatively, the current may travel the same path in the opposite direction.

Note that although the first via414and the second via424are illustrated as cylindrical vias, similar to the via130, it will be appreciated that the first via414and the second via424may be elongated vias, similar to the elongated via230, and may provide the same advantages.

The presence of the third curved metal plate430may provide better (i.e., lower) DC resistance and thermal conductivity along with lower inductor power loss compared to a conventional spiral inductor, such as the spiral inductor300. For example, the configuration of the stacked co-spiral inductor400may provide a 60% lower power loss than a conventional single layer spiral inductor (e.g., spiral inductor300). When integrated with a coreless substrate, the stacked co-spiral inductor400may also reduce external components, cost, and area on the substrate. For example, the stacked co-spiral inductor400may take up an area of 1.41 mm2on the substrate compared to an area of 1.69 mm2for the spiral inductor300. The DC resistance of the stacked co-spiral inductor400may be approximately 23.1 mOhm for 7 nanoHenries (nH), while the DC resistance of the spiral inductor300may be approximately 67.4 mOhm for 7 nH. The power loss at 2 Amps for the stacked co-spiral inductor400may be approximately 92.3 mW compared to approximately 270 mW for the spiral inductor300. Finally, the RF resistance for the stacked co-spiral inductor400may be a Q-factor of approximately 103 at 1 GHz with 7 nH compared to a Q-factor of approximately 101 at 1 GHz with 7 nH for the spiral inductor300.

The substrate may be one or more layers of silicon dioxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (SiON), tantalum pentoxide (Ta2O5), aluminum oxide (Al2O3), hafnium oxide (HfO2), benzocyclobutene (BCB), polyimide (PI), polybenzoxazoles (PBO), or other material having similar insulating and structural properties, as is known in the art. The first curved metal plate410, the second curved metal plate420, the third curved metal plate430, the first via414, and the second via424may be one or more layers of aluminum (Al), copper (Cu), tin (Sn), nickel (Ni), gold (Au), silver (Ag), or other suitable electrically conductive material, as is known in the art.

Note that as used herein, the terms “substantially” and “approximately” are not relative terms of degree, but rather, reflect the reality that, due to tolerances in manufacturing processes, two components may not be exactly the same size or have an exact orientation with respect to each other, or that a given component may not be an exact size. Rather, the terms “substantially” and “approximately” mean that the size, orientation, etc. of the component(s) need only be within some tolerance threshold of the described size, orientation, etc. Thus, for example, when one component is described as being “substantially” above or below another component, it means that the components are aligned vertically within some tolerance threshold. Similarly, as another example, when one component is described as being “approximately” a given size, it means that the component is within a given tolerance threshold of the given size. The tolerance threshold may be determined by the capabilities of the manufacturing process, the requirements of the device and/or components being manufactured, and the like.

It will be appreciated that even if the terms “substantially” or “approximately” are not used to describe a size, orientation, etc. of component(s), it does not mean that the size, orientation, etc. of the component(s) must be exactly the described size, orientation, etc. Rather, the described size, orientation, etc. need only be within some tolerance threshold of the described size, orientation, etc.

FIG. 5illustrates an exemplary power amplification (PA) circuit500with multiple inductors in accordance with some examples of the disclosure. As shown inFIG. 5, the PA circuit500may include a ground510, a power supply520, a first inductor530(e.g., inductor200or stacked co-spiral inductor400) coupled to the power supply520, an input540, such as an antenna input, coupled between the first inductor530and the ground510that gates the PA circuit500, a bandpass filter550coupled between the first inductor530and the input540, an RF resistive load560coupled between the bandpass filter550and the ground510, and an output tap570across the RF resistive load560. The bandpass filter550may include one or more inductors (e.g., inductor200or stacked co-spiral inductor400) and acoustic filters.

In this description, certain terminology is used to describe certain features. The term “mobile device” can describe, and is not limited to, a music player, a video player, an entertainment unit, a navigation device, a communications device, a mobile device, a mobile phone, a smartphone, a personal digital assistant, a fixed location terminal, a tablet computer, a computer, a wearable device, a laptop computer, a server, an automotive device in an automotive vehicle, and/or other types of portable electronic devices typically carried by a person and/or having communication capabilities (e.g., wireless, cellular, infrared, short-range radio, etc.). Further, the terms “user equipment” (UE), “mobile terminal,” “mobile device,” and “wireless device,” can be interchangeable.

Inductors and circuits according to the examples above (e.g., the inductor200, the stacked co-spiral inductor400, and the PA circuit500) can be used for a number of different applications, such as in the circuit components of a mobile device. Referring toFIG. 6as an example, a user equipment (UE)600(here a wireless device) has a platform602that can receive and execute software applications, data, and/or commands transmitted from a radio access network (RAN) that may ultimately come from a core network, the Internet, and/or other remote servers and networks. Platform602can include inductors and PA circuits as well as a transceiver606operably coupled to an application specific integrated circuit (ASIC)608, or other processor, microprocessor, logic circuit, or other data processing device. The ASIC608or other processor executes the application programming interface (API)610layer that interfaces with any resident programs in a memory612of the UE600. Memory612can be comprised of read-only memory (ROM) or random-access memory (RAM), electrically erasable programmable ROM (EEPROM), flash cards, or any memory common to computer platforms. Platform602can also include a local database614that can hold applications not actively used in memory612. Local database614is typically a flash memory cell, but can be any secondary storage device as known in the art, such as magnetic media, EEPROM, optical media, tape, soft or hard disk, or the like. Platform602components can also be operably coupled to external devices such as antenna622, display624, push-to-talk button628, and keypad626among other components, as is known in the art.

The wireless communication between UE600and the RAN can be based on different technologies, such as code division multiple access (CDMA), wideband CDMA (W-CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), Global System for Mobile Communications (GSM), 3GPP Long Term Evolution (LTE), or other protocols that may be used in a wireless communications network or a data communications network.

FIG. 7illustrates an exemplary flow700for forming an inductor device, such as inductor200, in accordance with some examples of the disclosure. The flow illustrated inFIG. 7may be performed during a manufacturing process of the inductor device. In an embodiment, the inductor device may be one of an RF front end module, a filter, or a PA. The inductor device may be incorporated into a device selected from a group comprising a music player, a video player, an entertainment unit, a navigation device, a communications device, a mobile device, a mobile phone, a smartphone, a personal digital assistant, a fixed location terminal, a tablet computer, a computer, a wearable device, a laptop computer, a server, an automotive device in an automotive vehicle, an RF front end module, a filter, or a PA.

At702, the flow700includes forming a first curved metal plate, such as first curved metal plate210inFIGS. 2A and 2B. At704, the flow700includes forming a second curved metal plate, such as second curved metal plate220inFIGS. 2A and 2B, below and substantially vertically aligned with the first curved metal plate. In an embodiment, the first curved metal plate and the second curved metal plate may be octagon shaped. The first curved metal plate and the second curved metal plate may have approximately a same length.

At706, the flow700includes forming a first elongated via, such as elongated via230inFIGS. 2A and 2B, vertically aligned between the first curved metal plate and the second curved metal plate. The first elongated via may be configured to conductively couple the first curved metal plate to the second curved metal plate and may have an aspect ratio of a width to a height of the first elongated via of at least approximately 2 to 1. The first elongated via may be completely within a vertical perimeter defined by an inside edge and an outside edge of the first curved metal plate.

At708, the flow700may optionally include providing a coreless substrate, such as insulating layer240inFIG. 2B, between the first curved metal plate and the second curved metal plate.

At710, the flow700may optionally include forming a third curved metal plate, such as the third curved metal plate430inFIG. 4, below and substantially vertically aligned with the second curved metal plate.

At712, the flow700may optionally include forming a second elongated via, such as the second via424inFIG. 4, vertically aligned between the second curved metal plate and the third curved metal plate. The second elongated via may be configured to conductively couple the second curved metal plate to the third curved metal plate and may have an aspect ratio of a width to a height of at least approximately 2 to 1.

AlthoughFIG. 7illustrates a particular order of operations, it will be appreciated that the operations may be performed in a different order, depending on the manufacturing process being used to form the inductor device.

It should be noted that the terms “connected,” “coupled,” or any variant thereof, mean any connection or coupling, either direct or indirect, between elements, and can encompass a presence of an intermediate element between two elements that are “connected” or “coupled” together via the intermediate element.

Any reference herein to an element using a designation such as “first,” “second,” and so forth does not limit the quantity and/or order of those elements. Rather, these designations are used as a convenient method of distinguishing between two or more elements and/or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must necessarily precede the second element. Also, unless stated otherwise, a set of elements can comprise one or more elements.

Nothing stated or illustrated in this application is intended to dedicate any component, action, feature, benefit, advantage, or equivalent to the public, regardless of whether the component, action, feature, benefit, advantage, or the equivalent is recited in the claims.

Although some aspects have been described in connection with a device, it goes without saying that these aspects also constitute a description of the corresponding method, and so a block or a component of a device should also be understood as a corresponding method action or as a feature of a method action. Analogously thereto, aspects described in connection with or as a method action also constitute a description of a corresponding block, detail, or feature of a corresponding device. Some or all of the method actions can be performed by a hardware apparatus (or using a hardware apparatus), such as, for example, a microprocessor, a programmable computer or an electronic circuit. In some examples, some or a plurality of the most important method actions can be performed by such an apparatus.

In the detailed description above it can be seen that different features are grouped together in examples. This manner of disclosure should not be understood as an intention that the claimed examples require more features than are explicitly mentioned in the respective claim. Rather, the situation is such that inventive content may reside in fewer than all features of an individual example disclosed. Therefore, the following claims should hereby be deemed to be incorporated in the description, wherein each claim by itself can stand as a separate example. Although each claim by itself can stand as a separate example, it should be noted that—although a dependent claim can refer in the claims to a specific combination with one or a plurality of claims—other examples can also encompass or include a combination of said dependent claim with the subject matter of any other dependent claim or a combination of any feature with other dependent and independent claims. Such combinations are proposed herein, unless it is explicitly expressed that a specific combination is not intended. Furthermore, it is also intended that features of a claim can be included in any other independent claim, even if said claim is not directly dependent on the independent claim.

It should furthermore be noted that methods disclosed in the description or in the claims can be implemented by a device comprising means for performing the respective actions of this method.

Furthermore, in some examples, an individual action can be subdivided into a plurality of sub-actions or contain a plurality of sub-actions. Such sub-actions can be contained in the disclosure of the individual action and be part of the disclosure of the individual action.

While the foregoing disclosure shows illustrative examples of the disclosure, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions and/or actions of the method claims in accordance with the examples of the disclosure described herein need not be performed in any particular order. Additionally, well-known elements will not be described in detail or may be omitted so as to not obscure the relevant details of the aspects and examples disclosed herein. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.