Disclosed embodiments are related to radio frequency (RF) filters. More particularly, exemplary embodiments are directed to three-dimensional (3D) RF inductor-capacitor (LC) band pass filters comprising through-glass-vias (TGVs).
Inductors are used extensively in analog circuits and signal processing. Inductors in conjunction with capacitors and other components can be used to form tuned circuits or L-C filters that can emphasize or filter out specific signal frequencies. Inductance (measured in henries H) is an effect which results from the magnetic field that forms around a current-carrying conductor. Factors such as the number of turns of the inductor, the area of each loop/turn, and the material it is wrapped around affect the inductance. The quality factor (or Q) of an inductor is a measure of its efficiency. The higher the Q of the inductor, the closer it approaches the behavior of an ideal, lossless, inductor. The Q of the inductor is directly proportional to its inductance L and inversely proportional to its internal electrical resistance R. Accordingly, the Q of the inductor may be increased by increasing L and/or by reducing R.
It is known in the art for designing small inductors for use in integrated circuits by etching them directly on a printed circuit board by laying out a trace in a spiral pattern. However, such planar inductors do not exhibit high Q. Moreover, planar inductors do not lend themselves well for coupling with other inductive elements in tuned circuits, or in other words, they do not exhibit a high coefficient of coupling K.
For analog RF and system on chip (SOC) applications, three dimensional inductors can be constructed as a coil of conducting material, such as copper wire or other suitable metal, wrapped around a core. The core may be air or may include a silicon substrate, glass, or magnetic material. Core materials with a higher permeability than air confine the magnetic field closely to the inductor, thereby increasing the inductance of the inductor. While three dimensional inductors that are known in the art exhibit better coefficient of coupling K than planar inductors, current technology has imposed limitations on the Q factor that is achievable for these inductors. For example, inductors formed on a glass substrate, or wrapped around a core made of glass can exhibit high permeability, coefficient of coupling, and Q factor. However, known techniques to construct inductors on a glass substrate rely on vias such as through-silicon-vias (TSVs) which take away from the desirable characteristics of glass substrates.
Accordingly, there is a need in the art for inductors and concomitant tuned circuit designs that exhibit high Q and high coefficient of coupling K.
Exemplary embodiments of the invention are directed to systems and method for radio frequency (RF) filters. More particularly, exemplary embodiments are directed to three-dimensional (3D) RF inductor-capacitor (L-C) band pass filters comprising through-glass-vias (TGVs).
For example, an exemplary embodiment is directed to a method of forming an L-C filter circuit on a glass substrate comprising: forming a first portion of a first inductor on a first surface of the glass substrate; forming a second portion of the first inductor on a second surface of the glass substrate; and connecting the first and second portions of the first inductor via through glass vias (TGVs).
Another exemplary embodiment is directed to an L-C filter circuit comprising: a glass substrate; a first portion of a first inductor formed on a first surface of the glass substrate; a second portion of the first inductor formed on a second surface of the glass substrate; and a first set of through-glass-vias (TGVs) configured to connect the first and second portions of the first inductor.
Another exemplary embodiment is directed to a method of forming an L-C filter circuit on a glass substrate comprising; step for forming a first portion of a first inductor on a first surface of the glass substrate; step for forming a second portion of the first inductor on a second surface of the glass substrate; and step for connecting the first and second portions of the first inductor via through-glass-vias (TGVs).
Yet another exemplary embodiment is directed to an L-C filter circuit comprising: a substrate means formed of glass; a first portion of a first inductance means formed on a first surface of the substrate means; a second portion of the first inductance means formed on a second surface of the substrate means; and a first set of through-glass-vias (TGVs) configured to connect the first and second portions of the first inductance means.
Yet another exemplary embodiment is directed to an L-C filter circuit comprising: a first L-C tank comprising a first inductor and a first capacitor coupled between a high voltage supply and ground; a second L-C tank comprising a second inductor and a second capacitor coupled between the high voltage supply and ground; and an L-C filter means coupling the first L-C tank and the second L-C tank, wherein the first and second inductors are three-dimensional solenoid inductors formed on a first and second surface of a glass substrate using through-glass-vias (TGVs), and wherein the first capacitor is formed as a metal-insulator-metal (MIM) capacitor between the first inductor and the second inductor on the first surface of the glass substrate, and the second capacitor is formed as a MIM capacitor between the second inductor and the L-C filter means on the first surface of the glass substrate.
The accompanying drawings are presented to aid in the description of embodiments of the invention and are provided solely for illustration of the embodiments and not limitation thereof.
Aspects of the invention are disclosed in the following description and related drawings directed to specific embodiments of the invention. Alternate embodiments may he devised without departing from the scope of the invention. Additionally, well-known elements of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term “embodiments of the invention” does not require that all embodiments of the invention include the discussed feature, advantage or mode of operation.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Further, many embodiments are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, these sequence of actions described herein can be considered to be embodied entirely within any form of computer readable storage medium having stored therein a corresponding set of computer instructions that upon execution would cause an associated processor to perform the functionality described herein. Thus, the various aspects of the invention may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the embodiments described herein, the corresponding form of any such embodiments may be described herein as, for example, “logic configured to” perform the described action.
Exemplary embodiments are directed to tuned circuits such as L-C band pass filters (BPFs) using inductive and capacitive elements which may be formed on glass substrate. Moreover, embodiments may include through-glass-vias (TGVs) to form connections between a first surface and a second surface of the glass substrates in order to form 3D BPFs. In this manner, embodiments may be configured to confine magnetic fields of the 3D BPFs to the glass substrates, thus enhancing their performance and reducing fluctuations in their corresponding frequency response characteristics. Embodiments using aforementioned TGVs may also be directed to particular circuit topologies for 3D L-C BPFs comprising inductor-coupling between L-C tanks in order to remove undesirable spurious fluctuations in the pass band of the frequency response.
With reference now to
In comparison to vias formed according to previously known technologies, the use of TGVs in exemplary embodiments to connect first portion 102 and second portion 106 through substrate 108 (which may be formed of glass) will lead to lower losses in inductance L of inductor 100. Further, thicker metal lines may be used for forming first portion 102 and second portion 106 over a glass substrate. Moreover, TGVs may be formed of greater thickness than previously known technologies for vias. Accordingly, thicker metal lines and vias will lead to lower resistance R through the turns of inductor 100. As will be seen, a higher inductance L along with a lower resistance R will contribute to a higher Q factor for inductor 100. Further, skilled persons will recognize that the 3D configuration of inductor 100 on glass substrate 108 will also confine the magnetic fields to the glass substrate, and thus further improve quality and reduce losses.
In some embodiments, a core such as a magnetic core may be provided to further improve the inductance of exemplary inductors. For example, with reference to
With reference now to
Moreover, with reference to
Turning now to
In addition to inductors L1-L4,
With reference now to
For example, with reference now to
For example, with reference to
In some embodiments, improved frequency response characteristics may be realized in conventional L-C BPF topologies by configuring these conventional L-C BPFs using exemplary 3D inductors and capacitors on glass substrates using TGVs. For example, with reference to
With reference to
Yet another L-C BPF configuration, wherein the circuit topology may be conventional, but the L-C components therein may be formed according to exemplary embodiments, is illustrated in
Accordingly, it can be seen that performance and frequency response characteristics of L-C BPF circuits may be improved by configuring the L-C BPFs with component L-C filter means such as inductors and capacitors on glass substrates using TGVs according to exemplary embodiments.
It will be appreciated that embodiments include various methods for performing the processes, functions and/or algorithms disclosed herein. For example, as illustrated in
Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The methods, sequences and/or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.
Accordingly, an embodiment of the invention can include a computer readable media embodying a method for L-C circuits on a glass substrate using TGVs. Accordingly, the invention is not limited to illustrated examples and any means for performing the functionality described herein are included in embodiments of the invention. Additional aspects are disclosed in the attached Appendix A, which forms part of this disclosure and is expressly incorporated herein in its entirety.
The foregoing disclosed devices and methods are typically designed and are configured into GDSII and GERBER computer files, stored on a computer readable media. These files are in turn provided to fabrication handlers who fabricate devices based on these files. The resulting products are semiconductor wafers that are then cut into semiconductor die and packaged into a semiconductor chip. The chips are then employed in devices described above
While the foregoing disclosure shows illustrative embodiments of the invention, it should be noted that various changes and modifications could be made herein without departing from the scope of the invention as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the embodiments of the invention described herein need not be performed in any particular order. Furthermore, although elements of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
Number | Date | Country | |
---|---|---|---|
61597953 | Feb 2012 | US |