Patent Publication Number: US-2021167014-A1

Title: Apparatus and method to increase effective capacitance with layout staples

Description:
BACKGROUND 
     Package power integrity analysis involves a complex estimation of an ideally desired platform, and this complex estimation includes package and on-die decoupling solution to contain power delivery noise on supply rails based on synthesized currents over time from on-die loading. Limited capacitance per unit area complicates the on-die decoupling solution. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments of the disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure, which, however, should not be taken to limit the disclosure to the specific embodiments, but are for explanation and understanding only. 
         FIG. 1  illustrates a top view of a regular Top Metal 0 (TM0) metal grid. 
         FIG. 2  illustrates a top view of a stapled TM0 metal grid, in accordance with some embodiments. 
         FIG. 3  illustrate two cross-sections of stapled TM0 metal grid of  FIG. 2  with top, middle, and bottom plates of a metal-insulator-metal (MIM) capacitor, in accordance with some embodiments. 
         FIG. 4  illustrate top views of a stapled TM0 metal grid with top plate and middle plate of a MIM capacitor, in accordance with some embodiments. 
         FIG. 5  illustrates a flowchart of forming the TM0 metal grid with staples, in accordance with some embodiments. 
         FIG. 6  illustrates a smart device or a computer system or a SoC (System-on-Chip) with stapled TM0 metal grid to increase capacitance of metal-insulator-metal (MIM) capacitors, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Historically, due to bandwidth limitations of a platform, package and on-die decoupling capacitors, transitionary peaks are observed in the Z(f) impedance profile over different frequency bands. This is an indication of lack of strong frequency-independent decoupling solutions from all fronts in totality. In some embodiments, the bandwidth of the on-die decoupling MIM (Metal-Insulator-Metal) capacitor is increased, e.g., by more than 3× of the previously observed baseline, by employing layout techniques involving TM0 (Top Metal 0) staples that are track-shared between several power supplies. Some embodiments use structured periodic stapled pattern of TM0 for a robust AC power delivery solution, aiding in reduction of overall power delivery noise and supply induced jitter. The scheme of various embodiments, is applicable to designs with more than one power supply rails within a given area to reap measurable benefits of stapling. 
     The scheme of some embodiments intelligently balances the existing TM0 resources to simultaneously boost both AC and DC power delivery topologies without incurring a penalty on either area or IR drop. TM0 tracks can be broadly divided into two categories—regular and staples. While regular tracks are continuous across the width of an active silicon (e.g., double data rate circuits, DDR PHY), staples are located right under the respective TM1 (Top Metal 1) tracks. TM1 is above TM0 in the hierarchy of metal layers. In one example, TM1 tracks are wider than TM0 tracks. The staples aid in tremendously increasing the total TV0 density for all supplies simultaneously as they are consecutively track-shared between the TM1 tracks, where TV0 refers to Top Via 0 that connects TM0 to TM1. This boost in via density helps reduce the net series resistance of the MIM capacitor as the Manhattan (displacement) distance between the supply and ground vias is now reduced. The outcome is a high-density high-bandwidth MIM capacitor, located between the main power distribution layers in the die metal stack—TM0 and TM1. 
     In some embodiments, an apparatus is provided comprising a first metal layer (e.g., TM0) comprising a first plurality of tracks, wherein the first plurality of tracks extends in a first direction (e.g., x-direction) and includes a first supply rail (e.g., Vcc1) and a first ground rail (e.g., V SS ). The apparatus further comprises a second metal layer (e.g., TM1) comprising a second plurality of tracks, wherein the second plurality of tracks extends in a second direction (e.g., y-direction) and includes a second supply rail (e.g., Vcc1) and a second ground rail (e.g., V SS ). While the embodiments describe a first layer having a first supply rail and a first ground rail, the first ground rail can be another supply rail, so long as there is potential different between the first supply rail and this other supply rail. Likewise, the second metal layer can also have two supply rails so long as there is a potential difference between the supply rails. In various embodiments, the first direction is orthogonal to the second direction. In some embodiments, the first metal layer is closer to a substrate than second metal layer. In some cases, MIM caps are formed between the first layer and second layer in process that does not include a substrate. 
     The apparatus further comprises a set of metal layers (e.g., plates of a MIM capacitor) between the first metal layer and the second metal layer, wherein the set of metal layers are configured as metal-insulator-metal (MIM) capacitors. The set of metal layers can be two or greater than two layers. For example, the MIM capacitors include a top metal plate and a bottom metal plate, and insulating material between the top and bottom metal plates. In other embodiments, an additional plate is provided between the top and bottom plates. This additional plate may be biased or grounded. 
     The apparatus further comprises a plurality of staples or stubs uniformly spread in a region over the set of metals, the plurality of staples or stubs are in contact with the second supply rail and extending under the second ground rail. In some embodiments, the first plurality of tracks is continuous across the second plurality of tracks to provide DC power delivery. In some embodiments, the plurality of staples or stubs extend in the first direction. In some embodiments, the plurality of staples or stubs occupy a track of the first plurality of tracks. For example, the plurality of staples or stubs is from a track which is uniformly broken into small segments that are 1-2 tracks long. In some embodiments, the plurality of staples or stubs are coupled to second supply rail through a via, wherein the second supply rail and the first supply rail are part of a same power supply rail. In some embodiments, the first plurality of tracks includes a third supply rail (e.g., Vcc2), wherein the plurality of staples or stubs is in contact with the third supply rail and extending under the second ground rail. In some embodiments, the substrate includes active devices including a first active device (e.g., a transistor) and a second active device (e.g., another transistor), wherein the first active device is powered by the second supply rail and is under the plurality of staples or stubs that is in contact with the second supply rail. In some embodiments, the second active device is powered by the third supply rail and is under the plurality of staples or stubs that is in contact with the third supply rail. 
     There are many technical effects of the various embodiments. For example, the structured periodic stapled pattern of TM0 staples almost eliminates the previous tradeoff between AC/Droop vs. DC/IR in the design of TM0/TM1 grid. The pattern of the staples results in net reduction in the overall power grid impedance seen in the Z(f) profile across frequencies. The pattern of the staples also reduces the impedance at package resonance thereby eliminating peaks by providing a more effective decoupling solution. The layout scheme of various embodiments aids package power integrity convergence with reduce AC noise and supply jitter. The scheme of various embodiments also assists in regulation for on-die low dropout voltage regulators for internal power supplies by aiding looping stability, phase margin, power supply noise rejection, etc. The periodic pattern of samples results in reduction in package capacitors thereby reducing total product bill-of-material (BOM) cost. Other technical effects will be evident from the various embodiments and figures. 
     In the following description, numerous details are discussed to provide a more thorough explanation of embodiments of the present disclosure. It will be apparent, however, to one skilled in the art, that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring embodiments of the present disclosure. 
     Note that in the corresponding drawings of the embodiments, signals are represented with lines. Some lines may be thicker, to indicate more constituent signal paths, and/or have arrows at one or more ends, to indicate primary information flow direction. Such indications are not intended to be limiting. Rather, the lines are used in connection with one or more exemplary embodiments to facilitate easier understanding of a circuit or a logical unit. Any represented signal, as dictated by design needs or preferences, may actually comprise one or more signals that may travel in either direction and may be implemented with any suitable type of signal scheme. 
       FIG. 1  illustrates a top view  100  of a regular Top Metal 0 (TM0) metal grid. The grid between TM0 and TM1 form a mesh between which MIM capacitor (MIMcap) is formed. TM0 and TM1 are orthogonal to one another. In this example horizontal layers of power supply (e.g., Vcc1, Vcc2, Vcc3) and ground (V SS ) rails on TM0, and vertical layers of power supply and ground rails coupled through contacts and vias form a metal grid or mesh. Between the TM0 and TM1 layers, MIM capacitor layers are formed, which include a top plate, a middle plate, and a bottom plate. The middle plate is usually coupled to ground, while the top and bottom plates are coupled to supply rails. 
     MIMcap is used to contain AC noise on power supplies for high speed IOs and other high-power application that use multiple supply rails, and to support better area scaling in accordance to Moore&#39;s law. Initial use of MIMcap helped lower the Vmin floor (minimum voltage required to meet performance targets) across analog and digital domains. Though capacitance density scaled over process technology generations, the sheet resistance per unit area for these MIMcap layers remained at more or less constant at typical process, voltage, and temperature (PVT) conditions. As such, the bandwidth of MIMcap bandwidth is, as implemented using the grid pattern of  FIG. 1 , limited due to constant sheet resistance as its ESR (Effective Series Resistance) slows down the MIMcap. Historically, the highest −3 dB bandwidth achieved on most supplies is in the range of 100 MHz to 200 MHz, which further dwindled on high-voltage stacked MIMcap. 
       FIG. 1  shows a TM0 uniform grid structure for Vcc1, Vcc2, and Vcc3 supplies. This continuous track pattern results in an ineffective utilization of resources between the supplies for both DC and AC power delivery. The IR drop may not necessarily be the lowest for the grid of  FIG. 1  as the circuits below each of the rails (supply and/or ground) may not be consuming all of the supplies, rendering some of the unused tracks redundant. This patterning of supply and ground rails as shown in  FIG. 1  does not factor in any localized current loading and what rail(s) the underlying circuits use, thereby resulting in higher IR drop on some supplies. This behavior may get worse with multiple power supplies like in DDR and occurrence could be random throughout the DDRPHY, for example. From an AC perspective, the grid pattern of  FIG. 1  degrades the MIM bandwidth even more as the periodicity of MIM tap points became very poor for all supplies. Some embodiments illustrate a stapled metal grid to mitigate the issues of the uniform grid layout of  FIG. 1 . 
       FIG. 2  illustrates top view  200  of a stapled TM0 metal grid, in accordance with some embodiments. The TM0 metal grid here include locally irregular but globally regular TM0 pattern, wherein merely those TM0 tracks required for DC power delivery are kept continuous across TM1s. In some embodiments, supply tracks are spatially placed right above circuits using them. As such, lowest IR drop is realized with current flowing via-down from TM0 all the way down to MO. Additional metal or bump layers may be used to go from the TM0/TM1 to the local transistor devices for power delivery. In some embodiments, a 3D die stacking or package assembly method may be used such that transistors are located on a different die than the die containing the MIM capacitor. 
     This local pattern changes significantly in width-spacing-pitch over every unique circuit based on current loading, but globally repeated on multiple-instantiated instances of the same unique circuit. As shown in  FIG. 2 , by converting the unused TM0s into track-shared staples  201  (Vcc1), 202 (Vcc2), and 203 (Vcc3), TV0 density is increased on all three supplies, hence reducing the effective series resistance of the MIM plates. 
       FIG. 1  depicts locations where there is already a presence of a regular grid in TM0 for vcc1, vcc2, and vcc3. However, the underlying circuits in the top-half use Vcc2 while those in the bottom half use Vcc1, while Vcc3 is unused over this region. By converting the unused TM0s into staples  201  (Vcc1),  202  (Vcc2), and 203 (Vcc3), as shown in  FIG. 2 , that are track-shared between Vcc1, Vcc2 and Vcc3, TV0 density is increased on all three supplies. This effectively increases the total tap-points to the MIM plates over the respective TM1, thereby reducing the effective series resistance of the plates. 
     In some embodiments, on wider TM1 tracks, a centered wider TV0 is replaced with smaller TV0s pushed to the edges of TM1. This additionally enhances the bandwidth as it purely scales by 1/(Distance between VCC-VSS Vias) 2 . Ultimately, this scheme delivers an optimum DC-AC power delivery solution. 
     In some embodiments, the TM0-staple periodicity is not more than a calculated pitch in a y-direction across an entire circuit domain or PHY. Increasing the frequency of the TM0 periodicity leads to a direct rise in the effective bandwidth (e.g., power supplies achieved 700 MHz-1 GHz (˜3× increase)). In some examples, an overall IR drop is kept at a minimum of 8-10 mV (˜1.5-2× reduction). 
     Package power delivery analysis is very sensitive to not just the MIMcap density but also the −3 dB bandwidth. Typically, the resonant frequency for each supply is estimated based on the package and platform extracted impedance profiles, which dictates a requirement on the total On-die decoupling solution for each rail. By boosting the MIMcap bandwidth, package power integrity and jitter analysis reaped immense benefits from the high-density high bandwidth MIMcap on several power supplies with lower noise from all terms and supply jitter. The layout technique described in this disclosure becomes extremely valuable on process nodes with higher MIM density (e.g., greater than 50 nF/mm 2 ) where it is difficult to get higher capacitance at higher frequencies. 
     Various embodiments include stapled metal in the top two layers where MIM resides. A stapled track (e.g.,  201 ,  202 ,  203 ) is defined as a track that is uniformly broken into very small segments that are 1-2 tracks long such that it&#39;s a pretty distinctive structure. While the technique of placing the staples are using in TM0, TM1, and MIMcap layers, the staples can be placed for other metal layers between which MIMcaps are formed. The layout technique can be used for MIMcaps used for on-die power delivery, voltage regulators, etc. The layout technique can also be used for IO partitions (e.g., double data rate (DDR) IOs, high-speed IOs (HSIO), Universal Serial Bus (USB), display ports), power management that use derived power rails due to Vmin constraints (e.g., static random-access memories (SRAMs), register files), always-on logic, etc. 
     The layout construction methodology using staples enables a simultaneous 3× improvement (from 100-300 MHz to 0.7-1 GHz) in MIMcap bandwidth and 2× improvement (under 5-10 mV) in top-level IR drop compared to the traditional layout method as a baseline. Staples provide AC power delivery (e.g., MIM bandwidth) while locally optimized routes provide DC power delivery (e.g., IR drop), enabling both to be better optimized for the final product. This style of implementation clearly facilitates an easier path to package power integrity (PI) convergence with a smaller contribution to the overall supply tolerance (AC noise components and DC IR drop) around V NOM . On the silicon side, a tighter supply tolerance can aid in a more straight-forward robust circuit design. A more controlled predictable power supply with a higher V MIN  directly translates to performance gains across the die—be it CPU, graphics processor (GFX), Memory, Analog or plain digital logic. 
       FIG. 3  illustrate two cross-sections  300  and  320  (AA′ and BB′) of stapled TM0 metal grid of  FIG. 2  with top, middle, and bottom plates of a metal-insulator-metal (MIM) capacitor, in accordance with some embodiments. The cross-sections show the MIM caps between TM1 and TM0. The MIM caps are formed by top plate  301 , middle plate  302 , and bottom plate  303 . In some embodiments, the middle plate connects to ground. Top plate  301  and bottom plate  303  is connects to supply rails. TM0 and TM1 are orthogonal to each other. The contacts shown in  FIG. 2  are connected to vias (TV0)  304 . In cross-section  300 , Vcc1 in TM1 is connected to Vcc1 in TM0 through TV0  304 . In cross-section  320 , V SS  in TM1 is connected to V SS  in TM0 through TV0  324 . 
       FIG. 4  illustrate top views  400  and  420  of a stapled TM0 metal grid with top plate  301  and middle plate  302  of a MIM capacitor, in accordance with some embodiments. Top and bottom MIM plates  301  and  303 , respectively, are line-on-line with each other. In various embodiments, MIM plates are shared and associated to different supplies (e.g., Vcc1, Vcc3, Vcc3) as shown. Top view  420  shows middle shared MIM plate  302  over metal. In this example, the metal plate is connected to V SS  or ground supply. While  FIG. 4  illustrates the top view of top plate  301  and middle plate  302 , a similar view of bottom plate  303  (not shown) is also contemplated, which is similar to the view of top plate  301 . 
       FIG. 5  illustrates flowchart  500  of forming the TM0 metal grid with staples, in accordance with some embodiments. While the blocks are shown in a particular order, the order can be modified. For example, some blocks may be performed in parallel, while some blocks can be performed before others. The various blocks can be performed by software, hardware, or a combination of then. 
     At block  501 , for a given region bounded by X1,Y2, and X2,Y2, the number of power supplies present with TM1 netname are detected. At block  502 , for each supply, user inputs are obtained. Examples of user inputs include supply on which MIM cap is desired, TM0 staple width (x), TM0 staple periodicity (n), TM0 bottom-most track offset with respect to block horizontal bottom boundary (Y0). Other user inputs may include the relative capacitance targets for each rail and/or MIM target allocation per rail. At block  503 , relevant process technology parameters are obtained from process collateral on legal layout design rules to achieve clean design rule check (DRC) layout. At block  504 , TM0 is converted at every Y m+1 =Y m +n (m≥0) if already present into a common netname=staple. For every staple TM0 at Ym+1, cut or chop the track on the left edge of every TM1 netname not equal to V SS . At block  505 , netname for each chopped staple track is re-assigned to match the TM1 netname above it where TM1 netname is not equal to V SS . At block  507 , a determination is made whether all staples are added in the bounded region X1,Y2, and X2,Y2. If more staples can be added, the process proceeds to block  501  and repeated till block  506 . When all staples are added, the process proceeds to block  508 . At block  508 , vias are inserted and DRC is performed. At block  509 , MIMcap regions are defined and the process of MIMcap generation is deemed complete. 
     Elements of embodiments are also provided as a machine-readable medium (e.g., memory) for storing the computer-executable instructions (e.g., instructions to implement any other processes discussed herein). In some embodiments, a computing platform comprises a memory, a processor, a machine-readable storage media (also referred to as tangible machine readable medium), a communication interface (e.g., wireless or wired interface), and a network bus coupling them. 
     In some embodiments, the processor is a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a general-purpose Central Processing Unit (CPU), or a low power logic implementing a simple finite state machine to perform the method of various embodiments, etc. 
     In some embodiments, the various logic blocks of the system are coupled together via the network bus. Any suitable protocol may be used to implement the network bus. In some embodiments, the machine-readable storage medium includes instructions (also referred to as the program software code/instructions) for intelligent prediction of processor idle time as described with reference to the various embodiments and flowchart. 
     Program software code/instructions associated with flowchart  500  (and/or various embodiments) and executed to implement embodiments of the disclosed subject matter may be implemented as part of an operating system or a specific application, component, program, object, module, routine, or other sequence of instructions or organization of sequences of instructions referred to as “program software code/instructions,” “operating system program software code/instructions,” “application program software code/instructions,” or simply “software” or firmware embedded in processor. In some embodiments, the program software code/instructions associated with flowchart  500  (and/or various embodiments) are executed by the computer system. 
     In some embodiments, the program software code/instructions associated with flowchart  500  (and/or various embodiments) are stored in a computer executable storage medium and executed by the processor. Here, computer executable storage medium is a tangible machine-readable medium that can be used to store program software code/instructions and data that, when executed by a computing device, causes one or more processors to perform a method(s) as may be recited in one or more accompanying claims directed to the disclosed subject matter. 
     The tangible machine-readable medium may include storage of the executable software program code/instructions and data in various tangible locations, including for example ROM, volatile RAM, non-volatile memory and/or cache and/or other tangible memory as referenced in the present application. Portions of this program software code/instructions and/or data may be stored in any one of these storage and memory devices. Further, the program software code/instructions can be obtained from other storage, including, e.g., through centralized servers or peer to peer networks and the like, including the Internet. Different portions of the software program code/instructions and data can be obtained at different times and in different communication sessions or in the same communication session. 
     The software program code/instructions (associated with flowchart  500  and other embodiments) and data can be obtained in their entirety prior to the execution of a respective software program or application by the computing device. Alternatively, portions of the software program code/instructions and data can be obtained dynamically, e.g., just in time, when needed for execution. Alternatively, some combination of these ways of obtaining the software program code/instructions and data may occur, e.g., for different applications, components, programs, objects, modules, routines or other sequences of instructions or organization of sequences of instructions, by way of example. Thus, it is not required that the data and instructions be on a tangible machine readable medium in entirety at a particular instance of time. 
     Examples of tangible computer-readable media include but are not limited to recordable and non-recordable type media such as volatile and non-volatile memory devices, read only memory (ROM), random access memory (RAM), flash memory devices, magnetic random-access memory, ferroelectric memory, floppy and other removable disks, magnetic storage media, optical storage media (e.g., Compact Disk Read-Only Memory (CD ROMS), Digital Versatile Disks (DVDs), etc.), among others. The software program code/instructions may be temporarily stored in digital tangible communication links while implementing electrical, optical, acoustical or other forms of propagating signals, such as carrier waves, infrared signals, digital signals, etc. through such tangible communication links. 
     In general, the tangible machine readable medium includes any tangible mechanism that provides (i.e., stores and/or transmits in digital form, e.g., data packets) information in a form accessible by a machine (i.e., a computing device), which may be included, e.g., in a communication device, a computing device, a network device, a personal digital assistant, a manufacturing tool, a mobile communication device, whether or not able to download and run applications and subsidized applications from the communication network, such as the Internet, e.g., an iPhone®, Galaxy®, Blackberry® Droid®, or the like, or any other device including a computing device. In one embodiment, processor-based system is in a form of or included within a PDA (personal digital assistant), a cellular phone, a notebook computer, a tablet, a game console, a set top box, an embedded system, a TV (television), a personal desktop computer, etc. Alternatively, the traditional communication applications and subsidized application(s) may be used in some embodiments of the disclosed subject matter. 
       FIG. 6  illustrates a smart device or a computer system or a SoC (System-on-Chip) with stapled TM0 metal grid to increase effective capacitance of metal-insulator-metal (MIM) capacitors, in accordance with some embodiments. While the technique described herein is used for increasing effective capacitance on a supply rail, the same technique can be used to increase effective capacitance of the MIM capacitor on any node where MIM capacitor is attached. It is pointed out that those elements of  FIG. 6  having the same reference numbers (or names) as the elements of any other figure may operate or function in any manner similar to that described, but are not limited to such. Any block in this smart device can have the apparatus for dynamically optimizing battery charging voltage. 
     In some embodiments, device  5500  represents an appropriate computing device, such as a computing tablet, a mobile phone or smart-phone, a laptop, a desktop, an Internet-of-Things (IOT) device, a server, a wearable device, a set-top box, a wireless-enabled e-reader, or the like. It will be understood that certain components are shown generally, and not all components of such a device are shown in device  5500 . 
     In an example, the device  5500  comprises an SoC (System-on-Chip)  5501 . An example boundary of the SoC  5501  is illustrated using dotted lines in  FIG. 6 , with some example components being illustrated to be included within SoC  5501 —however, SoC  5501  may include any appropriate components of device  5500 . 
     In some embodiments, device  5500  includes processor  5504 . Processor  5504  can include one or more physical devices, such as microprocessors, application processors, microcontrollers, programmable logic devices, processing cores, or other processing implementations such as disaggregated combinations of multiple compute, graphics, accelerator, I/O and/or other processing chips. The processing operations performed by processor  5504  include the execution of an operating platform or operating system on which applications and/or device functions are executed. The processing operations include operations related to I/O (input/output) with a human user or with other devices, operations related to power management, operations related to connecting computing device  5500  to another device, and/or the like. The processing operations may also include operations related to audio I/O and/or display I/O. 
     In some embodiments, processor  5504  includes multiple processing cores (also referred to as cores)  5508   a ,  5508   b ,  5508   c . Although merely three cores  5508   a ,  5508   b ,  5508   c  are illustrated in  FIG. 6 , processor  5504  may include any other appropriate number of processing cores, e.g., tens, or even hundreds of processing cores. Processor cores  5508   a ,  5508   b ,  5508   c  may be implemented on a single integrated circuit (IC) chip. Moreover, the chip may include one or more shared and/or private caches, buses or interconnections, graphics and/or memory controllers, or other components. 
     In some embodiments, processor  5504  includes cache  5506 . In an example, sections of cache  5506  may be dedicated to individual cores  5508  (e.g., a first section of cache  5506  dedicated to core  5508   a , a second section of cache  5506  dedicated to core  5508   b , and so on). In an example, one or more sections of cache  5506  may be shared among two or more of cores  5508 . Cache  5506  may be split in different levels, e.g., level 1 (L1) cache, level 2 (L2) cache, level 3 (L3) cache, etc. 
     In some embodiments, processor core  5504  may include a fetch unit to fetch instructions (including instructions with conditional branches) for execution by the core  5504 . The instructions may be fetched from any storage devices such as the memory  5530 . Processor core  5504  may also include a decode unit to decode the fetched instruction. For example, the decode unit may decode the fetched instruction into a plurality of micro-operations. Processor core  5504  may include a schedule unit to perform various operations associated with storing decoded instructions. For example, the schedule unit may hold data from the decode unit until the instructions are ready for dispatch, e.g., until all source values of a decoded instruction become available. In one embodiment, the schedule unit may schedule and/or issue (or dispatch) decoded instructions to an execution unit for execution. 
     The execution unit may execute the dispatched instructions after they are decoded (e.g., by the decode unit) and dispatched (e.g., by the schedule unit). In an embodiment, the execution unit may include more than one execution unit (such as an imaging computational unit, a graphics computational unit, a general-purpose computational unit, etc.). The execution unit may also perform various arithmetic operations such as addition, subtraction, multiplication, and/or division, and may include one or more an arithmetic logic units (ALUs). In an embodiment, a co-processor (not shown) may perform various arithmetic operations in conjunction with the execution unit. 
     Further, execution unit may execute instructions out-of-order. Hence, processor core  5504  may be an out-of-order processor core in one embodiment. Processor core  5504  may also include a retirement unit. The retirement unit may retire executed instructions after they are committed. In an embodiment, retirement of the executed instructions may result in processor state being committed from the execution of the instructions, physical registers used by the instructions being de-allocated, etc. Processor core  5504  may also include a bus unit to enable communication between components of processor core  5504  and other components via one or more buses. Processor core  5504  may also include one or more registers to store data accessed by various components of the core  5504  (such as values related to assigned app priorities and/or sub-system states (modes) association. 
     In some embodiments, device  5500  comprises connectivity circuitries  5531 . For example, connectivity circuitries  5531  includes hardware devices (e.g., wireless and/or wired connectors and communication hardware) and/or software components (e.g., drivers, protocol stacks), e.g., to enable device  5500  to communicate with external devices. Device  5500  may be separate from the external devices, such as other computing devices, wireless access points or base stations, etc. 
     In an example, connectivity circuitries  5531  may include multiple different types of connectivity. To generalize, the connectivity circuitries  5531  may include cellular connectivity circuitries, wireless connectivity circuitries, etc. Cellular connectivity circuitries of connectivity circuitries  5531  refers generally to cellular network connectivity provided by wireless carriers, such as provided via GSM (global system for mobile communications) or variations or derivatives, CDMA (code division multiple access) or variations or derivatives, TDM (time division multiplexing) or variations or derivatives, 3rd Generation Partnership Project (3GPP) Universal Mobile Telecommunications Systems (UMTS) system or variations or derivatives, 3GPP Long-Term Evolution (LTE) system or variations or derivatives, 3GPP LTE-Advanced (LTE-A) system or variations or derivatives, Fifth Generation (5G) wireless system or variations or derivatives, 5G mobile networks system or variations or derivatives, 5G New Radio (NR) system or variations or derivatives, or other cellular service standards. Wireless connectivity circuitries (or wireless interface) of the connectivity circuitries  5531  refers to wireless connectivity that is not cellular, and can include personal area networks (such as Bluetooth, Near Field, etc.), local area networks (such as Wi-Fi), and/or wide area networks (such as WiMax), and/or other wireless communication. In an example, connectivity circuitries  5531  may include a network interface, such as a wired or wireless interface, e.g., so that a system embodiment may be incorporated into a wireless device, for example, a cell phone or personal digital assistant. 
     In some embodiments, device  5500  comprises control hub  5532 , which represents hardware devices and/or software components related to interaction with one or more I/O devices. For example, processor  5504  may communicate with one or more of display  5522 , one or more peripheral devices  5524 , storage devices  5528 , one or more other external devices  5529 , etc., via control hub  5532 . Control hub  5532  may be a chipset, a Platform Control Hub (PCH), and/or the like. 
     For example, control hub  5532  illustrates one or more connection points for additional devices that connect to device  5500 , e.g., through which a user might interact with the system. For example, devices (e.g., devices  5529 ) that can be attached to device  5500  include microphone devices, speaker or stereo systems, audio devices, video systems or other display devices, keyboard or keypad devices, or other I/O devices for use with specific applications such as card readers or other devices. 
     As mentioned above, control hub  5532  can interact with audio devices, display  5522 , etc. For example, input through a microphone or other audio device can provide input or commands for one or more applications or functions of device  5500 . Additionally, audio output can be provided instead of, or in addition to display output. In another example, if display  5522  includes a touch screen, display  5522  also acts as an input device, which can be at least partially managed by control hub  5532 . There can also be additional buttons or switches on computing device  5500  to provide I/O functions managed by control hub  5532 . In one embodiment, control hub  5532  manages devices such as accelerometers, cameras, light sensors or other environmental sensors, or other hardware that can be included in device  5500 . The input can be part of direct user interaction, as well as providing environmental input to the system to influence its operations (such as filtering for noise, adjusting displays for brightness detection, applying a flash for a camera, or other features). 
     In some embodiments, control hub  5532  may couple to various devices using any appropriate communication protocol, e.g., PCIe (Peripheral Component Interconnect Express), USB (Universal Serial Bus), Thunderbolt, High Definition Multimedia Interface (HDMI), Firewire, etc. 
     In some embodiments, display  5522  represents hardware (e.g., display devices) and software (e.g., drivers) components that provide a visual and/or tactile display for a user to interact with device  5500 . Display  5522  may include a display interface, a display screen, and/or hardware device used to provide a display to a user. In some embodiments, display  5522  includes a touch screen (or touch pad) device that provides both output and input to a user. In an example, display  5522  may communicate directly with the processor  5504 . Display  5522  can be one or more of an internal display device, as in a mobile electronic device or a laptop device or an external display device attached via a display interface (e.g., DisplayPort, etc.). In one embodiment display  5522  can be a head mounted display (HMD) such as a stereoscopic display device for use in virtual reality (VR) applications or augmented reality (AR) applications. 
     In some embodiments, and although not illustrated in the figure, in addition to (or instead of) processor  5504 , device  5500  may include Graphics Processing Unit (GPU) comprising one or more graphics processing cores, which may control one or more aspects of displaying contents on display  5522 . 
     Control hub  5532  (or platform controller hub) may include hardware interfaces and connectors, as well as software components (e.g., drivers, protocol stacks) to make peripheral connections, e.g., to peripheral devices  5524 . 
     It will be understood that device  5500  could both be a peripheral device to other computing devices, as well as have peripheral devices connected to it. Device  5500  may have a “docking” connector to connect to other computing devices for purposes such as managing (e.g., downloading and/or uploading, changing, synchronizing) content on device  5500 . Additionally, a docking connector can allow device  5500  to connect to certain peripherals that allow computing device  5500  to control content output, for example, to audiovisual or other systems. 
     In addition to a proprietary docking connector or other proprietary connection hardware, device  5500  can make peripheral connections via common or standards-based connectors. Common types can include a Universal Serial Bus (USB) connector (which can include any of a number of different hardware interfaces), DisplayPort including MiniDisplayPort (MDP), High Definition Multimedia Interface (HDMI), Firewire, or other types. 
     In some embodiments, connectivity circuitries  5531  may be coupled to control hub  5532 , e.g., in addition to, or instead of, being coupled directly to the processor  5504 . In some embodiments, display  5522  may be coupled to control hub  5532 , e.g., in addition to, or instead of, being coupled directly to processor  5504 . 
     In some embodiments, device  5500  comprises memory  5530  coupled to processor  5504  via memory interface  5534 . Memory  5530  includes memory devices for storing information in device  5500 . 
     In some embodiments, memory  5530  includes apparatus to maintain stable clocking as described with reference to various embodiments. Memory can include nonvolatile (state does not change if power to the memory device is interrupted) and/or volatile (state is indeterminate if power to the memory device is interrupted) memory devices. Memory device  5530  can be a dynamic random-access memory (DRAM) device, a static random-access memory (SRAM) device, flash memory device, phase-change memory device, or some other memory device having suitable performance to serve as process memory. In one embodiment, memory  5530  can operate as system memory for device  5500 , to store data and instructions for use when the one or more processors  5504  executes an application or process. Memory  5530  can store application data, user data, music, photos, documents, or other data, as well as system data (whether long-term or temporary) related to the execution of the applications and functions of device  5500 . 
     Elements of various embodiments and examples are also provided as a machine-readable medium (e.g., memory  5530 ) for storing the computer-executable instructions (e.g., instructions to implement any other processes discussed herein). The machine-readable medium (e.g., memory  5530 ) may include, but is not limited to, flash memory, optical disks, CD-ROMs, DVD ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, phase change memory (PCM), or other types of machine-readable media suitable for storing electronic or computer-executable instructions. For example, embodiments of the disclosure may be downloaded as a computer program (e.g., BIOS) which may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals via a communication link (e.g., a modem or network connection). 
     In some embodiments, device  5500  comprises temperature measurement circuitries  5540 , e.g., for measuring temperature of various components of device  5500 . In an example, temperature measurement circuitries  5540  may be embedded, or coupled or attached to various components, whose temperature are to be measured and monitored. For example, temperature measurement circuitries  5540  may measure temperature of (or within) one or more of cores  5508   a ,  5508   b ,  5508   c , voltage regulator  5514 , memory  5530 , a mother-board of SoC  5501 , and/or any appropriate component of device  5500 . In some embodiments, temperature measurement circuitries  5540  include a low power hybrid reverse (LPHR) bandgap reference (BGR) and digital temperature sensor (DTS), which utilizes subthreshold metal oxide semiconductor (MOS) transistor and the PNP parasitic Bi-polar Junction Transistor (BJT) device to form a reverse BGR that serves as the base for configurable BGR or DTS operating modes. The LPHR architecture uses low-cost MOS transistors and the standard parasitic PNP device. Based on a reverse bandgap voltage, the LPHR can work as a configurable BGR. By comparing the configurable BGR with the scaled base-emitter voltage, the circuit can also perform as a DTS with a linear transfer function with single-temperature trim for high accuracy. 
     In some embodiments, device  5500  comprises power measurement circuitries  5542 , e.g., for measuring power consumed by one or more components of the device  5500 . In an example, in addition to, or instead of, measuring power, the power measurement circuitries  5542  may measure voltage and/or current. In an example, the power measurement circuitries  5542  may be embedded, or coupled or attached to various components, whose power, voltage, and/or current consumption are to be measured and monitored. For example, power measurement circuitries  5542  may measure power, current and/or voltage supplied by one or more voltage regulators  5514 , power supplied to SoC  5501 , power supplied to device  5500 , power consumed by processor  5504  (or any other component) of device  5500 , etc. 
     In some embodiments, device  5500  comprises one or more voltage regulator circuitries, generally referred to as voltage regulator (VR)  5514 . VR  5514  generates signals at appropriate voltage levels, which may be supplied to operate any appropriate components of the device  5500 . Merely as an example, VR  5514  is illustrated to be supplying signals to processor  5504  of device  5500 . In some embodiments, VR  5514  receives one or more Voltage Identification (VID) signals, and generates the voltage signal at an appropriate level, based on the VID signals. Various type of VRs may be utilized for the VR  5514 . For example, VR  5514  may include a “buck” VR, “boost” VR, a combination of buck and boost VRs, low dropout (LDO) regulators, switching DC-DC regulators, constant-on-time controller-based DC-DC regulator, etc. Buck VR is generally used in power delivery applications in which an input voltage needs to be transformed to an output voltage in a ratio that is smaller than unity. Boost VR is generally used in power delivery applications in which an input voltage needs to be transformed to an output voltage in a ratio that is larger than unity. In some embodiments, each processor core has its own VR, which is controlled by PCU  5510   a/b  and/or PMIC  5512 . In some embodiments, each core has a network of distributed LDOs to provide efficient control for power management. The LDOs can be digital, analog, or a combination of digital or analog LDOs. In some embodiments, VR  5514  includes current tracking apparatus to measure current through power supply rail(s). 
     In some embodiments, VR  5514  includes a digital control scheme to manage states of a proportional-integral-derivative (PID) filter (also known as a digital Type-III compensator). The digital control scheme controls the integrator of the PID filter to implement non-linear control of saturating the duty cycle during which the proportional and derivative terms of the PID are set to 0 while the integrator and its internal states (previous values or memory) is set to a duty cycle that is the sum of the current nominal duty cycle plus a deltaD. The deltaD is the maximum duty cycle increment that is used to regulate a voltage regulator from ICCmin to ICCmax and is a configuration register that can be set post silicon. A state machine moves from a non-linear all ON state (which brings the output voltage Vout back to a regulation window) to an open loop duty cycle which maintains the output voltage slightly higher than the required reference voltage Vref. After a certain period in this state of open loop at the commanded duty cycle, the state machine then ramps down the open loop duty cycle value until the output voltage is close to the Vref commanded. As such, output chatter on the output supply from VR  5514  is completely eliminated (or substantially eliminated) and there is merely a single undershoot transition which could lead to a guaranteed Vmin based on a comparator delay and the di/dt of the load with the available output decoupling capacitance. 
     In some embodiments, VR  5514  includes a separate self-start controller, which is functional without fuse and/or trim information. The self-start controller protects VR  5514  against large inrush currents and voltage overshoots, while being capable of following a variable VID (voltage identification) reference ramp imposed by the system. In some embodiments, the self-start controller uses a relaxation oscillator built into the controller to set the switching frequency of the buck converter. The oscillator can be initialized using either a clock or current reference to be close to a desired operating frequency. The output of VR  5514  is coupled weakly to the oscillator to set the duty cycle for closed loop operation. The controller is naturally biased such that the output voltage is always slightly higher than the set point, eliminating the need for any process, voltage, and/or temperature (PVT) imposed trims. 
     In some embodiments, device  5500  comprises one or more clock generator circuitries, generally referred to as clock generator  5516 . Clock generator  5516  generates clock signals at appropriate frequency levels, which may be supplied to any appropriate components of device  5500 . Merely as an example, clock generator  5516  is illustrated to be supplying clock signals to processor  5504  of device  5500 . In some embodiments, clock generator  5516  receives one or more Frequency Identification (FID) signals, and generates the clock signals at an appropriate frequency, based on the FID signals. 
     In some embodiments, device  5500  comprises battery  5518  supplying power to various components of device  5500 . Merely as an example, battery  5518  is illustrated to be supplying power to processor  5504 . Although not illustrated in the figures, device  5500  may comprise a charging circuitry, e.g., to recharge the battery, based on Alternating Current (AC) power supply received from an AC adapter. 
     In some embodiments, battery  5518  periodically checks an actual battery capacity or energy with charge to a preset voltage (e.g., 4.1 V). The battery then decides of the battery capacity or energy. If the capacity or energy is insufficient, then an apparatus in or associated with the battery slightly increases charging voltage to a point where the capacity is sufficient (e.g. from 4.1 V to 4.11 V). The process of periodically checking and slightly increase charging voltage is performed until charging voltage reaches specification limit (e.g., 4.2 V). The scheme described herein has benefits such as battery longevity can be extended, risk of insufficient energy reserve can be reduced, burst power can be used as long as possible, and/or even higher burst power can be used. 
     In some embodiments, battery  5518  is a multi-battery system with workload dependent load-sharing mechanism. The mechanism is an energy management system that operates in three modes—energy saving mode, balancer mode, and turbo mode. The energy saving mode is a normal mode where the multiple batteries (collectively shown as battery  5518 ) provide power to their own set of loads with least resistive dissipation. In balancing mode, the batteries are connected through switches operating in active mode so that the current shared is inversely proportion to the corresponding battery state-of-charge. In turbo mode, both batteries are connected in parallel through switches (e.g., on-switches) to provide maximum power to a processor or load. In some embodiments, battery  5518  is a hybrid battery which comprising a fast charging battery and a high energy density battery. Fast charging battery (FC) means a battery capable of faster charging than high energy density battery (HE). FC may be today&#39;s Li-ion battery as it is capable of faster charging than HE. In some embodiments, a controller (part of battery  5518 ) optimizes the sequence and charging rate for the hybrid battery to maximize both the charging current and charging speed of the battery, while enabling longer battery life. 
     In some embodiments, the charging circuitry (e.g.,  5518 ) comprises a buck-boost converter. This buck-boost converter comprises DrMOS or DrGaN devices used in place of half-bridges for traditional buck-boost converters. Various embodiments here are described with reference to DrMOS. However, the embodiments are applicable to DrGaN. The DrMOS devices allow for better efficiency in power conversion due to reduced parasitic and optimized MOSFET packaging. Since the dead-time management is internal to the DrMOS, the dead-time management is more accurate than for traditional buck-boost converters leading to higher efficiency in conversion. Higher frequency of operation allows for smaller inductor size, which in turn reduces the z-height of the charger comprising the DrMOS based buck-boost converter. The buck-boost converter of various embodiments comprises dual-folded bootstrap for DrMOS devices. In some embodiments, in addition to the traditional bootstrap capacitors, folded bootstrap capacitors are added that cross-couple inductor nodes to the two sets of DrMOS switches. 
     In some embodiments, device  5500  comprises Power Control Unit (PCU)  5510  (also referred to as Power Management Unit (PMU), Power Management Controller (PMC), Power Unit (p-unit), etc.). In an example, some sections of PCU  5510  may be implemented by one or more processing cores  5508 , and these sections of PCU  5510  are symbolically illustrated using a dotted box and labelled PCU  5510   a . In an example, some other sections of PCU  5510  may be implemented outside the processing cores  5508 , and these sections of PCU  5510  are symbolically illustrated using a dotted box and labelled as PCU  5510   b . PCU  5510  may implement various power management operations for device  5500 . PCU  5510  may include hardware interfaces, hardware circuitries, connectors, registers, etc., as well as software components (e.g., drivers, protocol stacks), to implement various power management operations for device  5500 . 
     In various embodiments, PCU or PMU  5510  is organized in a hierarchical manner forming a hierarchical power management (HPM). HPM of various embodiments builds a capability and infrastructure that allows for package level management for the platform, while still catering to islands of autonomy that might exist across the constituent die in the package. HPM does not assume a pre-determined mapping of physical partitions to domains. An HPM domain can be aligned with a function integrated inside a dielet, to a dielet boundary, to one or more dielets, to a companion die, or even a discrete CXL device. HPM addresses integration of multiple instances of the same die, mixed with proprietary functions or 3rd party functions integrated on the same die or separate die, and even accelerators connected via CXL (e.g., Flexbus) that may be inside the package, or in a discrete form factor. 
     HPM enables designers to meet the goals of scalability, modularity, and late binding. HPM also allows PMU functions that may already exist on other dice to be leveraged, instead of being disabled in the flat scheme. HPM enables management of any arbitrary collection of functions independent of their level of integration. HPM of various embodiments is scalable, modular, works with symmetric multi-chip processors (MCPs), and works with asymmetric MCPs. For example, HPM does not need a signal PM controller and package infrastructure to grow beyond reasonable scaling limits. HPM enables late addition of a die in a package without the need for change in the base die infrastructure. HPM addresses the need of disaggregated solutions having dies of different process technology nodes coupled in a single package. HPM also addresses the needs of companion die integration solutions—on and off package. 
     In various embodiments, each die (or dielet) includes a power management unit (PMU) or p-unit. For example, processor dies can have a supervisor p-unit, supervisee p-unit, or a dual role supervisor/supervisee p-unit. In some embodiments, an I/O die has its own dual role p-unit such as supervisor and/or supervisee p-unit. The p-units in each die can be instances of a generic p-unit. In one such example, all p-units have the same capability and circuits, but are configured (dynamically or statically) to take a role of a supervisor, supervisee, and/or both. In some embodiments, the p-units for compute dies are instances of a compute p-unit while p-units for IO dies are instances of an IO p-unit different from the compute p-unit. Depending on the role, p-unit acquires specific responsibilities to manage power of the multichip module and/or computing platform. While various p-units are described for dies in a multichip module or system-on-chip, a p-unit can also be part of an external device such as I/O device. 
     Here, the various p-units do not have to be the same. The HPM architecture can operate very different types of p-units. One common feature for the p-units is that they are expected to receive HPM messages and are expected to be able to comprehend them. In some embodiments, the p-unit of IO dies may be different than the p-unit of the compute dies. For example, the number of register instances of each class of register in the IO p-unit is different than those in the p-units of the compute dies. An IO die has the capability of being an HPM supervisor for CXL connected devices, but compute die may not need to have that capability. The IO and computes dice also have different firmware flows and possibly different firmware images. These are choices that an implementation can make. An HPM architecture can choose to have one superset firmware image and selectively execute flows that are relevant to the die type the firmware is associated with. Alternatively, there can be a customer firmware for each p-unit type; it can allow for more streamlined sizing of the firmware storage requirements for each p-unit type. 
     The p-unit in each die can be configured as a supervisor p-unit, supervisee p-unit or with a dual role of supervisor/supervisee. As such, p-units can perform roles of supervisor or supervisee for various domains. In various embodiments, each instance of p-unit is capable of autonomously managing local dedicated resources and contains structures to aggregate data and communicate between instances to enable shared resource management by the instance configured as the shared resource supervisor. A message and wire-based infrastructure is provided that can be duplicated and configured to facilitate management and flows between multiple p-units. 
     In some embodiments, power and thermal thresholds are communicated by a supervisor p-unit to supervisee p-units. For example, a supervisor p-unit learns of the workload (present and future) of each die, power measurements of each die, and other parameters (e.g., platform level power boundaries) and determines new power limits for each die. These power limits are then communicated by supervisor p-units to the supervisee p-units via one or more interconnects and fabrics. In some embodiments, a fabric indicates a group of fabrics and interconnect including a first fabric, a second fabric, and a fast response interconnect. In some embodiments, the first fabric is used for common communication between a supervisor p-unit and a supervisee p-unit. These common communications include change in voltage, frequency, and/or power state of a die which is planned based on a number of factors (e.g., future workload, user behavior, etc.). In some embodiments, the second fabric is used for higher priority communication between supervisor p-unit and supervisee p-unit. Example of higher priority communication include a message to throttle because of a possible thermal runaway condition, reliability issue, etc. In some embodiments, a fast response interconnect is used for communicating fast or hard throttle of all dies. In this case, a supervisor p-unit may send a fast throttle message to all other p-units, for example. In some embodiments, a fast response interconnect is a legacy interconnect whose function can be performed by the second fabric. 
     The HPM architecture of various embodiments enables scalability, modularity, and late binding of symmetric and/or asymmetric dies. Here, symmetric dies are dies of same size, type, and/or function, while asymmetric dies are dies of different size, type, and/or function. Hierarchical approach also allows PMU functions that may already exist on other dice to be leveraged, instead of being disabled in the traditional flat power management scheme. HPM does not assume a pre-determined mapping of physical partitions to domains. An HPM domain can be aligned with a function integrated inside a dielet, to a dielet boundary, to one or more dielets, to a companion die, or even a discrete CXL device. HPM enables management of any arbitrary collection of functions independent of their level of integration. In some embodiments, a p-unit is declared a supervisor p-unit based on one or more factors. These factors include memory size, physical constraints (e.g., number of pin-outs), and locations of sensors (e.g., temperature, power consumption, etc.) to determine physical limits of the processor. 
     The HPM architecture of various embodiments, provides a means to scale power management so that a single p-unit instance does not need to be aware of the entire processor. This enables power management at a smaller granularity and improves response times and effectiveness. Hierarchical structure maintains a monolithic view to the user. For example, at an operating system (OS) level, HPM architecture gives the OS a single PMU view even though the PMU is physically distributed in one or more supervisor-supervisee configurations. 
     In some embodiments, the HPM architecture is centralized where one supervisor controls all supervisees. In some embodiments, the HPM architecture is decentralized, wherein various p-units in various dies control overall power management by peer-to-peer communication. In some embodiments, the HPM architecture is distributed where there are different supervisors for different domains. One example of a distributed architecture is a tree-like architecture. 
     In some embodiments, device  5500  comprises Power Management Integrated Circuit (PMIC)  5512 , e.g., to implement various power management operations for device  5500 . In some embodiments, PMIC  5512  is a Reconfigurable Power Management ICs (RPMICs) and/or an IMVP (Intel® Mobile Voltage Positioning). In an example, the PMIC is within an IC die separate from processor  5504 . The may implement various power management operations for device  5500 . PMIC  5512  may include hardware interfaces, hardware circuitries, connectors, registers, etc., as well as software components (e.g., drivers, protocol stacks), to implement various power management operations for device  5500 . 
     In an example, device  5500  comprises one or both PCU  5510  or PMIC  5512 . In an example, any one of PCU  5510  or PMIC  5512  may be absent in device  5500 , and hence, these components are illustrated using dotted lines. 
     Various power management operations of device  5500  may be performed by PCU  5510 , by PMIC  5512 , or by a combination of PCU  5510  and PMIC  5512 . For example, PCU  5510  and/or PMIC  5512  may select a power state (e.g., P-state) for various components of device  5500 . For example, PCU  5510  and/or PMIC  5512  may select a power state (e.g., in accordance with the ACPI (Advanced Configuration and Power Interface) specification) for various components of device  5500 . Merely as an example, PCU  5510  and/or PMIC  5512  may cause various components of the device  5500  to transition to a sleep state, to an active state, to an appropriate C state (e.g., CO state, or another appropriate C state, in accordance with the ACPI specification), etc. In an example, PCU  5510  and/or PMIC  5512  may control a voltage output by VR  5514  and/or a frequency of a clock signal output by the clock generator, e.g., by outputting the VID signal and/or the FID signal, respectively. In an example, PCU  5510  and/or PMIC  5512  may control battery power usage, charging of battery  5518 , and features related to power saving operation. 
     The clock generator  5516  can comprise a phase locked loop (PLL), frequency locked loop (FLL), or any suitable clock source. In some embodiments, each core of processor  5504  has its own clock source. As such, each core can operate at a frequency independent of the frequency of operation of the other core. In some embodiments, PCU  5510  and/or PMIC  5512  performs adaptive or dynamic frequency scaling or adjustment. For example, clock frequency of a processor core can be increased if the core is not operating at its maximum power consumption threshold or limit. In some embodiments, PCU  5510  and/or PMIC  5512  determines the operating condition of each core of a processor, and opportunistically adjusts frequency and/or power supply voltage of that core without the core clocking source (e.g., PLL of that core) losing lock when the PCU  5510  and/or PMIC  5512  determines that the core is operating below a target performance level. For example, if a core is drawing current from a power supply rail less than a total current allocated for that core or processor  5504 , then PCU  5510  and/or PMIC  5512  can temporality increase the power draw for that core or processor  5504  (e.g., by increasing clock frequency and/or power supply voltage level) so that the core or processor  5504  can perform at higher performance level. As such, voltage and/or frequency can be increased temporality for processor  5504  without violating product reliability. 
     In an example, PCU  5510  and/or PMIC  5512  may perform power management operations, e.g., based at least in part on receiving measurements from power measurement circuitries  5542 , temperature measurement circuitries  5540 , charge level of battery  5518 , and/or any other appropriate information that may be used for power management. To that end, PMIC  5512  is communicatively coupled to one or more sensors to sense/detect various values/variations in one or more factors having an effect on power/thermal behavior of the system/platform. Examples of the one or more factors include electrical current, voltage droop, temperature, operating frequency, operating voltage, power consumption, inter-core communication activity, etc. One or more of these sensors may be provided in physical proximity (and/or thermal contact/coupling) with one or more components or logic/IP blocks of a computing system. Additionally, sensor(s) may be directly coupled to PCU  5510  and/or PMIC  5512  in at least one embodiment to allow PCU  5510  and/or PMIC  5512  to manage processor core energy at least in part based on value(s) detected by one or more of the sensors. 
     Also illustrated is an example software stack of device  5500  (although not all elements of the software stack are illustrated). Merely as an example, processors  5504  may execute application programs  5550 , Operating System  5552 , one or more Power Management (PM) specific application programs (e.g., generically referred to as PM applications  5558 ), and/or the like. PM applications  5558  may also be executed by the PCU  5510  and/or PMIC  5512 . OS  5552  may also include one or more PM applications  5556   a ,  5556   b ,  5556   c . The OS  5552  may also include various drivers  5554   a ,  5554   b ,  5554   c , etc., some of which may be specific for power management purposes. In some embodiments, device  5500  may further comprise a Basic Input/output System (BIOS)  5520 . BIOS  5520  may communicate with OS  5552  (e.g., via one or more drivers  5554 ), communicate with processors  5504 , etc. 
     For example, one or more of PM applications  5558 ,  5556 , drivers  5554 , BIOS  5520 , etc. may be used to implement power management specific tasks, e.g., to control voltage and/or frequency of various components of device  5500 , to control wake-up state, sleep state, and/or any other appropriate power state of various components of device  5500 , control battery power usage, charging of the battery  5518 , features related to power saving operation, etc. 
     In some embodiments, battery  5518  is a Li-metal battery with a pressure chamber to allow uniform pressure on a battery. The pressure chamber is supported by metal plates (such as pressure equalization plate) used to give uniform pressure to the battery. The pressure chamber may include pressured gas, elastic material, spring plate, etc. The outer skin of the pressure chamber is free to bow, restrained at its edges by (metal) skin, but still exerts a uniform pressure on the plate that is compressing the battery cell. The pressure chamber gives uniform pressure to battery, which is used to enable high-energy density battery with, for example, 20% more battery life. 
     In some embodiments, battery  5518  includes hybrid technologies. For example, a mix of high energy density charge (e.g., Li-ion batteries) carrying device(s) and low energy density charge carrying devices (e.g., supercapacitor) are used as batteries or storage devices. In some embodiments, a controller (e.g., hardware, software, or a combination of them) is used analyze peak power patterns and minimizes the impact to overall lifespan of high energy density charge carrying device-based battery cells while maximizing service time for peak power shaving feature. The controller may be part of battery  5518  or part of p-unit  5510   b.    
     In some embodiments, pCode executing on PCU  5510   a/b  has a capability to enable extra compute and telemetries resources for the runtime support of the pCode. Here pCode refers to a firmware executed by PCU  5510   a/b  to manage performance of the SoC  5501 . For example, pCode may set frequencies and appropriate voltages for the processor. Part of the pCode are accessible via OS  5552 . In various embodiments, mechanisms and methods are provided that dynamically change an Energy Performance Preference (EPP) value based on workloads, user behavior, and/or system conditions. There may be a well-defined interface between OS  5552  and the pCode. The interface may allow or facilitate the software configuration of several parameters and/or may provide hints to the pCode. As an example, an EPP parameter may inform a pCode algorithm as to whether performance or battery life is more important. 
     This support may be done as well by the OS  5552  by including machine-learning support as part of OS  5552  and either tuning the EPP value that the OS hints to the hardware (e.g., various components of SoC  5501 ) by machine-learning prediction, or by delivering the machine-learning prediction to the pCode in a manner similar to that done by a Dynamic Tuning Technology (DTT) driver. In this model, OS  5552  may have visibility to the same set of telemetries as are available to a DTT. As a result of a DTT machine-learning hint setting, pCode may tune its internal algorithms to achieve optimal power and performance results following the machine-learning prediction of activation type. The pCode as example may increase the responsibility for the processor utilization change to enable fast response for user activity, or may increase the bias for energy saving either by reducing the responsibility for the processor utilization or by saving more power and increasing the performance lost by tuning the energy saving optimization. This approach may facilitate saving more battery life in case the types of activities enabled lose some performance level over what the system can enable. The pCode may include an algorithm for dynamic EPP that may take the two inputs, one from OS  5552  and the other from software such as DTT, and may selectively choose to provide higher performance and/or responsiveness. As part of this method, the pCode may enable in the DTT an option to tune its reaction for the DTT for different types of activity. 
     In some embodiments, pCode improves the performance of the SoC in battery mode. In some embodiments, pCode allows drastically higher SoC peak power limit levels (and thus higher Turbo performance) in battery mode. In some embodiments, pCode implements power throttling and is part of Intel&#39;s Dynamic Tuning Technology (DTT). In various embodiments, the peak power limit is referred to PL4. However, the embodiments are applicable to other peak power limits. In some embodiments, pCode sets the Vth threshold voltage (the voltage level at which the platform will throttle the SoC) in such a way as to prevent the system from unexpected shutdown (or black screening). In some embodiments, pCode calculates the Psoc,pk SoC Peak Power Limit (e.g., PL4), according to the threshold voltage (Vth). These are two dependent parameters, if one is set, the other can be calculated. pCode is used to optimally set one parameter (Vth) based on the system parameters, and the history of the operation. In some embodiments, pCode provides a scheme to dynamically calculate the throttling level (Psoc,th) based on the available battery power (which changes slowly) and set the SoC throttling peak power (Psoc,th). In some embodiments, pCode decides the frequencies and voltages based on Psoc,th. In this case, throttling events have less negative effect on the SoC performance Various embodiments provide a scheme which allows maximum performance (Pmax) framework to operate. 
     In some embodiments, VR  5514  includes a current sensor to sense and/or measure current through a high-side switch of VR  5514 . In some embodiments the current sensor uses an amplifier with capacitively coupled inputs in feedback to sense the input offset of the amplifier, which can be compensated for during measurement. In some embodiments, the amplifier with capacitively coupled inputs in feedback is used to operate the amplifier in a region where the input common-mode specifications are relaxed, so that the feedback loop gain and/or bandwidth is higher. In some embodiments, the amplifier with capacitively coupled inputs in feedback is used to operate the sensor from the converter input voltage by employing high-PSRR (power supply rejection ratio) regulators to create a local, clean supply voltage, causing less disruption to the power grid in the switch area. In some embodiments, a variant of the design can be used to sample the difference between the input voltage and the controller supply, and recreate that between the drain voltages of the power and replica switches. This allows the sensor to not be exposed to the power supply voltage. In some embodiments, the amplifier with capacitively coupled inputs in feedback is used to compensate for power delivery network related (PDN-related) changes in the input voltage during current sensing. 
     Some embodiments use three components to adjust the peak power of SoC  5501  based on the states of a USB TYPE-C device  5529 . These components include OS Peak Power Manager (part of OS  5552 ), USB TYPE-C Connector Manager (part of OS  5552 ), and USB TYPE-C Protocol Device Driver (e.g., one of drivers  5554   a ,  5554   b ,  5554   c ). In some embodiments, the USB TYPE-C Connector Manager sends a synchronous request to the OS Peak Power Manager when a USB TYPE-C power sink device is attached or detached from SoC  5501 , and the USB TYPE-C Protocol Device Driver sends a synchronous request to the Peak Power Manager when the power sink transitions device state. In some embodiments, the Peak Power Manager takes power budget from the CPU when the USB TYPE-C connector is attached to a power sink and is active (e.g., high power device state). In some embodiments, the Peak Power Manager gives back the power budget to the CPU for performance when the USB TYPE-C connector is either detached or the attached and power sink device is idle (lowest device state). 
     In some embodiments, logic is provided to dynamically pick the best operating processing core for BIOS power-up flows and sleep exit flows (e.g., S3, S4, and/or S5). The selection of the bootstrap processor (BSP) is moved to an early power-up time instead of a fixed hardware selection at any time. For maximum boot performance, the logic selects the fastest capable core as the BSP at an early power-up time. In addition, for maximum power saving, the logic selects the most power efficient core as the BSP. Processor or switching for selecting the BSP happens during the boot-up as well as power-up flows (e.g., S3, S4, and/or S5 flows). 
     In some embodiments, the memories herein are organized in multi-level memory architecture and their performance is governed by a decentralized scheme. The decentralized scheme includes p-unit  5510  and memory controllers. In some embodiments, the scheme dynamically balances a number of parameters such as power, thermals, cost, latency and performance for memory levels that are progressively further away from the processor in platform  5500  based on how applications are using memory levels that are further away from processor cores. In some examples, the decision making for the state of the far memory (FM) is decentralized. For example, a processor power management unit (p-unit), near memory controller (NMC), and/or far memory host controller (FMHC) makes decisions about the power and/or performance state of the FM at their respective levels. These decisions are coordinated to provide the most optimum power and/or performance state of the FM for a given time. The power and/or performance state of the memories adaptively change to changing workloads and other parameters even when the processor(s) is in a particular power state. 
     In some embodiments, a hardware and software coordinated processor power state policy (e.g., policy for C-state) is implemented that delivers optimal power state selection by taking in to account the performance and/or responsiveness needs of thread expected to be scheduled on the core entering idle, to achieve improved instructions per cycle (IPC) and performance for cores running user critical tasks. The scheme provides the ability to deliver responsiveness gains for important and/or user-critical threads running on a system-on-chip. P-unit  5510  which coupled to the plurality of processing cores, receives a hint from operating system  5552  indicative of a bias towards a power state or performance state for at least one of the processing cores of the plurality of processing cores based on a priority of a thread in context switch. 
     Reference in the specification to “an embodiment,” “one embodiment,” “some embodiments,” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments. The various appearances of “an embodiment,” “one embodiment,” or “some embodiments” are not necessarily all referring to the same embodiments. If the specification states a component, feature, structure, or characteristic “may,” “might,” or “could” be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to “a” or “an” element, that does not mean there is only one of the elements. If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional elements. 
     Throughout the specification, and in the claims, the term “connected” means a direct connection, such as electrical, mechanical, or magnetic connection between the things that are connected, without any intermediary devices. 
     The term “coupled” means a direct or indirect connection, such as a direct electrical, mechanical, or magnetic connection between the things that are connected or an indirect connection, through one or more passive or active intermediary devices. 
     The term “adjacent” here generally refers to a position of a thing being next to (e.g., immediately next to or close to with one or more things between them) or adjoining another thing (e.g., abutting it). 
     The term “circuit” or “module” may refer to one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function. 
     The term “signal” may refer to at least one current signal, voltage signal, magnetic signal, or data/clock signal. The meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on.” 
     The term “analog signal” is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. 
     The term “digital signal” is a physical signal that is a representation of a sequence of discrete values (a quantified discrete-time signal), for example of an arbitrary bit stream, or of a digitized (sampled and analog-to-digital converted) analog signal. 
     The term “scaling” generally refers to converting a design (schematic and layout) from one process technology to another process technology and may be subsequently being reduced in layout area. In some cases, scaling also refers to upsizing a design from one process technology to another process technology and may be subsequently increasing layout area. The term “scaling” generally also refers to downsizing or upsizing layout and devices within the same technology node. The term “scaling” may also refer to adjusting (e.g., slowing down or speeding up—i.e. scaling down, or scaling up respectively) of a signal frequency relative to another parameter, for example, power supply level. 
     The terms “substantially,” “close,” “approximately,” “near,” and “about,” generally refer to being within +/−10% of a target value. 
     Unless otherwise specified the use of the ordinal adjectives “first,” “second,” and “third,” etc., to describe a common object, merely indicate that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking or in any other manner. 
     For the purposes of the present disclosure, phrases “A and/or B” and “A or B” mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). 
     The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. 
     It is pointed out that those elements of the figures having the same reference numbers (or names) as the elements of any other figure can operate or function in any manner similar to that described but are not limited to such. 
     For purposes of the embodiments, the transistors in various circuits and logic blocks described here are metal oxide semiconductor (MOS) transistors or their derivatives, where the MOS transistors include drain, source, gate, and bulk terminals. The transistors and/or the MOS transistor derivatives also include Tri-Gate and FinFET transistors, Gate All Around Cylindrical Transistors, Tunneling FET (TFET), Square Wire, or Rectangular Ribbon Transistors, ferroelectric FET (FeFETs), or other devices implementing transistor functionality like carbon nanotubes or spintronic devices. MOSFET symmetrical source and drain terminals i.e., are identical terminals and are interchangeably used here. A TFET device, on the other hand, has asymmetric Source and Drain terminals. Those skilled in the art will appreciate that other transistors, for example, Bi-polar junction transistors (BJT PNP/NPN), BiCMOS, CMOS, etc., may be used without departing from the scope of the disclosure. 
     Here the term “die” generally refers to a single continuous piece of semiconductor material (e.g. silicon) where transistors or other components making up a processor core may reside. Multi-core processors may have two or more processors on a single die, but alternatively, the two or more processors may be provided on two or more respective dies. Each die has a dedicated power controller or power control unit (p-unit) power controller or power control unit (p-unit) which can be dynamically or statically configured as a supervisor or supervisee. In some examples, dies are of the same size and functionality i.e., symmetric cores. However, dies can also be asymmetric. For example, some dies have different size and/or function than other dies. Each processor may also be a dielet or chiplet. 
     Here the term “dielet” or “chiplet” generally refers to a physically distinct semiconductor die, typically connected to an adjacent die in a way that allows the fabric across a die boundary to function like a single fabric rather than as two distinct fabrics. Thus at least some dies may be dielets. Each dielet may include one or more p-units which can be dynamically or statically configured as a supervisor, supervisee or both. 
     Here the term “fabric” generally refers to communication mechanism having a known set of sources, destinations, routing rules, topology and other properties. The sources and destinations may be any type of data handling functional unit such as power management units. Fabrics can be two-dimensional spanning along an x-y plane of a die and/or three-dimensional (3D) spanning along an x-y-z plane of a stack of vertical and horizontally positioned dies. A single fabric may span multiple dies. A fabric can take any topology such as mesh topology, star topology, daisy chain topology. A fabric may be part of a network-on-chip (NoC) with multiple agents. These agents can be any functional unit. 
     Here, the term “processor core” generally refers to an independent execution unit that can run one program thread at a time in parallel with other cores. A processor core may include a dedicated power controller or power control unit (p-unit) which can be dynamically or statically configured as a supervisor or supervisee. This dedicated p-unit is also referred to as an autonomous p-unit, in some examples. In some examples, all processor cores are of the same size and functionality i.e., symmetric cores. However, processor cores can also be asymmetric. For example, some processor cores have different size and/or function than other processor cores. A processor core can be a virtual processor core or a physical processor core. 
     Here, the term “interconnect” refers to a communication link, or channel, between two or more points or nodes. It may comprise one or more separate conduction paths such as wires, vias, waveguides, passive components, and/or active components. It may also comprise a fabric. In some embodiments, a p-unit is coupled to an OS via an interface. 
     Here the term “interface” generally refers to software and/or hardware used to communicate with an interconnect. An interface may include logic and I/O driver/receiver to send and receive data over the interconnect or one or more wires. 
     Here the term “domain” generally refers to a logical or physical perimeter that has similar properties (e.g., supply voltage, operating frequency, type of circuits or logic, and/or workload type) and/or is controlled by a particular agent. For example, a domain may be a group of logic units or function units that are controlled by a particular supervisor. A domain may also be referred to an Autonomous Perimeter (AP). A domain can be an entire system-on-chip (SoC) or part of the SoC, and is governed by a p-unit. 
     Here the term “supervisor” generally refers to a power controller, or power management, unit (a “p-unit”), which monitors and manages power and performance related parameters for one or more associated power domains, either alone or in cooperation with one or more other p-units. Power/performance related parameters may include but are not limited to domain power, platform power, voltage, voltage domain current, die current, load-line, temperature, device latency, utilization, clock frequency, processing efficiency, current/future workload information, and other parameters. It may determine new power or performance parameters (limits, average operational, etc.) for the one or more domains. These parameters may then be communicated to supervisee p-units, or directly to controlled or monitored entities such as VR or clock throttle control registers, via one or more fabrics and/or interconnects. A supervisor learns of the workload (present and future) of one or more dies, power measurements of the one or more dies, and other parameters (e.g., platform level power boundaries) and determines new power limits for the one or more dies. These power limits are then communicated by supervisor p-units to the supervisee p-units via one or more fabrics and/or interconnect. In examples where a die has one p-unit, a supervisor (Svor) p-unit is also referred to as supervisor die. 
     Here the term “supervisee” generally refers to a power controller, or power management, unit (a “p-unit”), which monitors and manages power and performance related parameters for one or more associated power domains, either alone or in cooperation with one or more other p-units and receives instructions from a supervisor to set power and/or performance parameters (e.g., supply voltage, operating frequency, maximum current, throttling threshold, etc.) for its associated power domain. In examples where a die has one p-unit, a supervisee (Svee) p-unit may also be referred to as a supervisee die. Note that a p-unit may serve either as a Svor, a Svee, or both a Svor/Svee p-unit 
     Furthermore, the particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more embodiments. For example, a first embodiment may be combined with a second embodiment anywhere the particular features, structures, functions, or characteristics associated with the two embodiments are not mutually exclusive. 
     While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of such embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description. The embodiments of the disclosure are intended to embrace all such alternatives, modifications, and variations as to fall within the broad scope of the appended claims. 
     In addition, well-known power/ground connections to integrated circuit (IC) chips and other components may or may not be shown within the presented figures, for simplicity of illustration and discussion, and so as not to obscure the disclosure. Further, arrangements may be shown in block diagram form in order to avoid obscuring the disclosure, and also in view of the fact that specifics with respect to implementation of such block diagram arrangements are highly dependent upon the platform within which the present disclosure is to be implemented (i.e., such specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that the disclosure can be practiced without, or with variation of, these specific details. The description is thus to be regarded as illustrative instead of limiting. 
     Various embodiments are described as examples. The examples can be combined in any suitable manner. For instance, example 5 can be combined with example 3 and/or example 7. 
     Example 1: An apparatus comprising: a first metal layer comprising a first plurality of tracks, wherein the first plurality of tracks extends in a first direction and includes a first supply rail and a first ground rail; a second metal layer comprising a second plurality of tracks, wherein the second plurality of tracks extends in a second direction and includes a second supply rail and a second ground rail, wherein the first direction is orthogonal to the second direction; a set of metal layers between the first metal layer and the second metal layer, wherein the set of metal layers are configured as metal-insulator-metal capacitors; and a plurality of staples or stubs uniformly spread in a region over the set of metals layers, the plurality of staples or stubs in contact with the second supply rail and extending under the second ground rail. 
     Example 2: The apparatus of example 1, wherein the first plurality of tracks that provide DC power delivery are continuous across the second plurality of tracks. 
     Example 3: The apparatus of example 1, wherein the plurality of staples or stubs extend in the first direction. 
     Example 4: The apparatus of example 1, wherein the plurality of staples or stubs occupy a track of the first plurality of tracks. 
     Example 5: The apparatus of example 1, wherein the plurality of staples or stubs are coupled to second supply rail through a via, wherein the second supply rail and the first supply rail are part of a same power supply rail. 
     Example 6: The apparatus of example 1, wherein the first plurality of tracks includes a third supply rail, wherein the plurality of staples or stubs is in contact with the third supply rail and extending under the second ground rail. 
     Example 7: The apparatus of example 6, wherein the first metal layer is closer to a substrate than second metal layer, wherein the substrate includes active devices including a first active device and a second active device, wherein the first active device is powered by the second supply rail and is under the plurality of staples or stubs that is in contact with the second supply rail. 
     Example 8: The apparatus of example 7, wherein the second active device is powered by the third supply rail and is under the plurality of staples or stubs that is in contact with the third supply rail. 
     Example 9: An apparatus comprising: a first metal layer comprising a first plurality of tracks, wherein the first plurality of tracks extends in a first direction and includes a first supply rail and a second supply rail; a second metal layer comprising a second plurality of tracks, wherein the second plurality of tracks extends in a second direction and includes a third supply rail and a fourth supply rail, wherein the first direction is orthogonal to the second direction, wherein the second metal layer is wider than the first metal layer; a set of metal layers between the first metal layer and the second metal layer, wherein the set of metal layers are configured as metal-insulator-metal capacitors; and a plurality of staples or stubs that are part of the first metal layer, wherein the plurality of staples or stubs is uniformly spread in a region over the set of metals, the plurality of staples or stubs in contact with the third supply rail and extending under the fourth supply rail. 
     Example 10: The apparatus of example 9, wherein there is a potential difference between the first supply rail and the second supply rail, and between the third supply rail and the fourth supply rail. 
     Example 11: The apparatus of example 9, wherein the first metal layer is closer to a substrate than second metal layer. 
     Example 12: The apparatus of example 11, wherein the first plurality of tracks includes a fifth supply rail, wherein the plurality of staples or stubs is in contact with the fifth supply rail and extending under the fourth supply rail. 
     Example 13: The apparatus of example 12, wherein the substrate includes active devices including a first active device and a second active device, wherein the first active device is powered by the third supply rail and is under the plurality of staples or stubs that is in contact with the third supply rail. 
     Example 14: The apparatus of example 13, wherein the second active device is powered by the fifth supply rail and is under the plurality of staples or stubs that is in contact with the fifth supply rail. 
     Example 15: A system comprising: a memory; a processor coupled to the memory; a wireless interface communicatively coupled to the processor, wherein the processor includes an apparatus comprising: a first metal layer comprising a first plurality of tracks, wherein the first plurality of tracks extends in a first direction and includes a first supply rail and a first ground rail; a second metal layer comprising a second plurality of tracks, wherein the second plurality of tracks extends in a second direction and includes a second supply rail and a second ground rail, wherein the first direction is orthogonal to the second direction, wherein the first metal layer is closer to a substrate than second metal layer; a set of metal layers between the first metal layer and the second metal layer, wherein the set of metal layers are configured as metal-insulator-metal capacitors; and a plurality of staples or stubs uniformly spread in a region over the set of metals layers, the plurality of staples or stubs in contact with the second supply rail and extending under the second ground rail. 
     Example 16: The system of example 15, wherein the first plurality of tracks that provide DC power delivery are continuous across the second plurality of tracks. 
     Example 17: The system of example 15, wherein the plurality of staples or stubs extend in the first direction. 
     Example 18: The system of example 15, wherein the plurality of staples or stubs occupy a track of the first plurality of tracks. 
     Example 19: The system of example 15, wherein the plurality of staples or stubs are coupled to second supply rail through a via, wherein the second supply rail and the first supply rail are part of a same power supply rail. 
     Example 20: The system of example 15, wherein the first plurality of tracks includes a third supply rail, wherein the plurality of staples or stubs is in contact with the third supply rail and extending under the second ground rail. 
     Example 21: The system of example 20, wherein the substrate includes active devices including a first active device and a second active device, wherein the first active device is powered by the second supply rail and is under the plurality of staples or stubs that is in contact with the second supply rail, wherein the second active device is powered by the third supply rail and is under the plurality of staples or stubs that is in contact with the third supply rail. 
     An abstract is provided that will allow the reader to ascertain the nature and gist of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.