Patent Publication Number: US-11387683-B2

Title: Composite integrated circuits and methods for wireless interactions therewith

Description:
PRIORITY CLAIM 
     This application is a continuation of U.S. patent application Ser. No. 16/220,514 filed on Dec. 14, 2018, which is a continuation of U.S. application Ser. No. 15/589,435 filed on May 8, 2017, now U.S. Pat. No. 10,164,480, issued Dec. 25, 2018, which is a continuation of U.S. patent application Ser. No. 14/804,319 filed on Jul. 20, 2015, now U.S. Pat. No. 9,653,927, issued May 16, 2017, which is a continuation-in-part of U.S. application Ser. No. 13/572,533, filed Aug. 10, 2012, now U.S. Pat. No. 9,086,452, issued Jul. 21, 2015, each of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The present disclosure relates to a three-dimensional integrated circuit (3DIC) and a method for an information access of the 3DIC, including composite integrated circuits and methods for wireless interactions with composite integrated circuits. 
     BACKGROUND 
     To access an information stored in a chip, conventionally, it requires extra power supplied and a sophisticated installation on tester, for example a probing card (or any other equipment) which may cause inconvenience. In addition, a manual touch or a machine contact would induce electrostatic discharge (ESD) damage for the chip. 
     Tracking information through controlled collapse chip connection (C 4 )/through substrate via (TSV) increases area penalty (extra layout of power/ground/signals on C 4 /TSV), and once one of the connections fails, the information is unreadable. 
     3DIC comprises a plurality of stacked chips provided from different companies or processes, and needs complete information recorded and being freely written/read, and the complete information comprises: company information, wafer tracking information (e.g., fabrication, process, part name and die-location), chip specification (test condition/setup and/or test results/parameters), and testing execution. Thus, there is a need to solve the above-mentioned problems. 
     SUMMARY 
     In accordance with one aspect of the present disclosure, a method for wireless information access in a three-dimensional integrated circuit (3DIC) includes steps of providing plural stacked chips including a wireless device, an information and a transmitting/receiving circuit; and accessing wirelessly the information via the wireless device and the transmitting/receiving circuit during a packaging process for the plural stacked chips. 
     In accordance with another aspect of the present disclosure, a testing method comprises steps of: providing a semiconductor structure having a wireless chip; wirelessly receiving a power by the wireless chip; and using the power to test the semiconductor structure. 
     In accordance with one more aspect of the present disclosure, a 3DIC comprises a semiconductor structure, and a wireless power device (WPD) formed on the semiconductor structure for wirelessly receiving a power for operating a function selected from a group consisting of probing the semiconductor structure, testing the semiconductor structure and accessing a first information from the semiconductor structure. 
     The present disclosure may best be understood through the following descriptions with reference to the accompanying drawings, in which; 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a 3DIC stacking, a server, a cloud foundry and a handy reader according to the first embodiment of the present disclosure; 
         FIG. 2  is a flow chart of a method for a wireless information access of a 3DIC stacking according to the second embodiment of the present disclosure; 
         FIG. 3  is a flow chart of a method for a wireless information access of a 3DIC stacking according to the third embodiment of the present disclosure; 
         FIG. 4  is a schematic diagram of a wireless power transfer (WPT) and a tag having an RF/analog front end, digital controller and a non-volatile memory (NVM) according to the fourth embodiment of the present disclosure; 
         FIG. 5( a )  is a schematic circuit diagram of two 3DIC stockings according to the fifth embodiment of the present disclosure; 
         FIG. 5( b )  is a schematic circuit diagram of a 3DIC stacking according to the sixth embodiment of the present disclosure; 
         FIG. 5( c )  is a schematic circuit diagram of a 3DIC stacking according to the seventh embodiment of the present disclosure; 
         FIG. 5( d )  is a schematic circuit diagram of a 3DIC stacking according to the eighth embodiment of the present disclosure; 
         FIG. 6  is a schematic diagram of a composite integrated circuit, in accordance with some embodiments; 
         FIG. 7  is a schematic diagram of a tracking circuit, in accordance with some embodiments; 
         FIG. 8  is a schematic diagram of a wireless communication system, in accordance with some embodiments; and 
         FIG. 9  is a flow chart of a method of accessing a semiconductor structure, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be described with respect to particular embodiments and with reference to certain drawings, but the disclosure is not limited thereto but is only limited by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice. 
     The present disclosure provides a 3DIC stacking, having a wireless power device (WPD) for wirelessly receiving a power for operating a function selected from a group consisting of probing the semiconductor structure, testing the semiconductor structure and accessing an information from the semiconductor structure, and a method thereof to avoid the ESD damage and the area penalty. 
     The present disclosure relates to a wireless tracking implement on a 3DIC stacking, and provides a chip information anywhere without any equipment installation.  FIG. 1  is a schematic diagram of a 3DIC stacking, a server, a cloud foundry and a handy reader according to the first embodiment of the present disclosure. The configuration of  FIG. 1  is set up for wirelessly accessing the information contained in a 3DIC stacking. The 3DIC stacking and the server are wirelessly connected, there are two antennas shown in  FIG. 1  too, where one antenna is for the 3DIC stacking and the other is for the server, and the 3DIC stacking and the handy reader are also wirelessly connected. However, the server and the cloud foundry are connected by a connection line, and so are the cloud foundry and the handy reader. The 3DIC stacking includes the chips (A, B, C and D) to be wirelessly accessed, which contains required information such as chip manufacturer&#39;s information, wafer tracking information, chip spec. and test execution information, and a radio frequency circuit (RF) for transmitting/receiving a radio frequency signal to/from the antenna of the 3DIC stacking. The Handy reader is an electronic book, being a tool for a user to read/write an information from/to the 3DIC stacking. The Cloud Foundry is an open platform as a service (also known as an open source cloud computing platform as a service (PaaS) software developed by VMware released under the terms of the Apache License 2.0). The server is a physical computer (a computer hardware system) dedicated to running one or more client-server services (as a host), to serve the needs of users of the other computers (clients) on the network. The server could be an Automatic or Automated Test Equipment (ATE), or the like. Each antenna is an electrical device which converts electric currents into radio waves, and vice versa. Each the antenna is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter applies an oscillating radio frequency electric current to the antenna&#39;s terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals that is applied to a receiver to be amplified. Each the antenna can be used for both transmitting and receiving. There are two connection lines, relatively between the Handy reader and the Cloud Foundry, and between the Cloud Foundry and the server, such that the required information related to the 3DIC stacking is quickly provided to (the user of) the Handy reader via the Cloud Foundry and the server in some embodiments. In some other embodiments, the user of the Handy reader sends out an instruction regarding the access of the information contained in the 3DIC stacking (e.g., reading an information) from the Handy reader via the antenna of the 3DIC stacking to the 3DIC stacking, and the 3DIC stacking reacts to provide a reply through the antenna of the 3DIC stacking, the antenna connected to the server, the server, the Cloud Foundry to the Handy reader such that the information contained in the 3DIC stacking is provided to (the user of) the Handy Reader. In some other embodiments, the user of the Handy reader sends out instructions regarding the access of the information contained in the 3DIC stacking (e.g., writing an information) from the Handy reader to the antenna of the 3DIC stacking and to the Cloud Foundry such that the information to be written could be sent to the 3DIC stacking through the Cloud foundry, the server, the antenna connected to the server, and the antenna of the 3DIC stacking. In some other embodiments, the user of the Handy reader sends out instructions regarding the access of the information contained in the 3DIC stacking (e.g., writing/reading an information) from the Handy reader to the antenna of the 3DIC stacking and receives the response of the 3DIC stacking from the antenna of the 3DIC stacking directly too. 
       FIG. 2  is a flow chart of a method for a wireless information access of a 3DIC stacking according to the second embodiment of the present disclosure. In the KGD (known good die) probing stage of the wafer level, a conventional installation including a tester as aforementioned is involved. But in accordance with the present disclosure, in the KGS (known good stacking) probing stage of the wafer level, and in the KGS testing stage of the package level, no tester is required, and the information is accessed wirelessly through a configuration as shown in  FIG. 1 . Since the information is accessed wirelessly in the KGS probing stage of the water level and in the KGS testing stage of the package level, and the wafer level installation for KGS as well as a power up signal connection required in both of the conventional KGS probing stage of the wafer level and the conventional KGS testing stage of the package level could be omitted. In the KGD probing stage of the wafer level, it performs a wafer level installation for KGD and a power up signal connection, and provides a write-in information (*1) for probing per die. Since a conventional tester is used in the KGD probing stage of the wafer level, the power needs to be provided after the KGD is installed in the tester such that the write-in information (*1) for probing per die could be proceeded when the power is turned on, in the wafer level, the KGS probing stage, it performs the 3DIC stacking process and provides an ID identification access information (*2), which is an optional step. In the package level, the KGS testing stage, it performs the packaging process, provides the ID identification access information (*2), and executes the shipment, where (*1) means write-in ID is necessary and writing/reading other data or testing are (is) optional, and (*2) means ID verification is necessary and writing/reading other data or testing are (is) optional. Since providing the ID identification access information (*2) is an optional step, there might be three different routes. The first one is from performing the stacking process to performing the packaging process, the second one is from performing the stacking process to providing the ID identification access information (*2) and then to performing the stacking process again, and the third one is from performing stacking process to providing the ID identification access information (*2) and then to performing the packaging process. The wireless information access is performed through embedded wireless chips. 
       FIG. 3  is a flow chart of a method for a wireless information access of a 3DIC stacking according to the third embodiment of the present disclosure.  FIG. 3  is similar to  FIG. 2  except that there is an extra step of providing a stacking plan (*3) for selected dies between performing a wafer level installation for KGD and performing a power up signal connection, the stacking plan is provided for certain chips purchased from other manufacturers or having no stacking plan at all, where (*3) indicates that the stacking plan of selected dies is decided by testing results and products after the KGD testing is done. The stacking plan is used to determine where these selected dies should be stacked on and whether a tracking die should be used. Similarly, since a conventional tester is used in the KGD probing stage of the wafer level, the power needs to be provided after the KGD is installed in the tester also such that the write-in information (*1) for probing per die could be proceeded when the power is turned on as shown in  FIG. 3 . Referring to  FIG. 3 , since the information is accessed wirelessly in the KGS probing stage of the wafer level and in the KGS testing stage of the package level, the wafer level installation for KGS as well as a power up signal connection required in both of the conventional KGS probing stage of the wafer level and the conventional KGS testing stage of the package level could be omitted too. The wireless information access is either performed through embedded wireless chips, or performed through extra embedded wireless chips (for those chips without any radio frequency (RF) circuit), which is accomplished via a configuration as shown in  FIG. 1 . 
       FIG. 4  is a schematic diagram of a wireless power transfer (WPT) and a tag having an RF/analog front end, digital controller and a non-volatile memory (NVM) according to the fourth embodiment of the present disclosure. The tag functions as a controller/register, the RF/analog front end performs all analog processing for DC power, receives signal detection/demodulation, and transmits modulation, the digital controller decodes incoming data, responds to commands from the transmitter (reader), reads and writes to internal memory, and encodes and transmits data to the modulator included in the RE/analog front end, and the NVM is necessary for one-time or multi-time data storage. 
     The function block of WPT is used as power transfer interface functioning as an antenna, the WPT can be made as an antenna, a capacitor, an inductor or any interface to receive power, and the WPT and the Tag are in the same chip or in two different stacked chips. The configuration of the WPT in the first layer and the tag in the second layer as shown in  FIG. 4  is used as an embedded wireless chip/IP in 3DIC stacked chip to record information. 
       FIG. 5( a )  is a schematic circuit diagram of two 3DIC stockings according to the fifth embodiment of the present disclosure. The first 3DIC stacking located on the left-hand side has a bottom layer being one of a passive substrate or an active substrate with a plurality of C 4  bumps disposed under the bottom layer of the first 3DIC stacking, and shows separated WPT and Tag in different chips, wherein the first WPT is disposed in the bottom layer, a first chip A has a tag disposed therein and connected with the first WPT, a second chip A has a tag disposed therein, and a chip B has a WPT disposed therein and connected to the tag of the second chip A. Also, the first 3DIC stacking includes a tower structure with a chip A and a chip B, wherein the chip A is disposed on the chip B and the chip B is disposed on the bottom layer. Furthermore, the first 3DIC stacking has a WPT and a Tag in one chip too, wherein the chip C having the WPT and the tag is disposed on the bottom layer. Lastly, the first 3DIC stacking also includes a nontracking circuit being a chip D disposed on the bottom layer and having no WPT/tag. The second 3DIC stacking is located on the right-hand side, has a bottom layer of E being a passive substrate or an active substrate, a chip A and a chip B, the chip A is disposed on the chip B and the chip B is disposed on the bottom layer. 
       FIG. 5( b )  is a schematic circuit diagram of a 3DIC stacking according to the sixth embodiment of the present disclosure. In  FIG. 5( b ) , at least one extra wireless chip (e.g., two tracking chips, wherein the first WPT is disposed in the bottom layer, being one of a passive substrate and an active substrate, the first tracking chip has a tag disposed therein and connected to the first WPT, and the second tracking chip has a second WPT and a tag connected to the second. WPT therein) is utilized to record information for chips/stacked chips without any RF circuit (e.g., a first chip D and a second chip D and a chip E, wherein the first chip D is disposed on the bottom layer, the chip E is disposed on the second chip D, and the second chip D is disposed on the bottom layer). 
       FIG. 5( c )  is a schematic circuit diagram of a 3DIC stacking according to the seventh embodiment of the present disclosure. It is desired to have a plurality of WPTs connecting to (at least) one tag for better transmitting/receiving operations. As shown in  FIG. 5( c ) , there are the first and the second WPTs, WPT- 1  and WPT- 2 , both disposed in the bottom layer, being one of a passive and an active substrate, and connected to a first tag, Tag- 1  disposed in a first chip A. There is a second tag, Tag- 2 , disposed in a first chip B, and WPT- 2  and a third WPT, disposed in the bottom layer, are both connected to Tag- 2 . Also, a second chip A having a fourth WPT is disposed on a second chip B having a third tag and a fifth WPT and disposed on the bottom layer. The fourth and the fifth WPTs are both connected to the third tag. Besides, there is a chip C having a sixth and a seventh WPTs and a fourth tag, and both of the sixth and the seventh WPTs are connected to the fourth tag. Thus, in  FIG. 5( c ) , it shows at least one WPT is connected to one Tag for better communication. 
       FIG. 5( d )  is a schematic circuit diagram of a 3DIC stacking according to the eighth embodiment of the present disclosure. It is desired to have (at least) one WPT connects to plurality of tags for parallel testing operations. In  FIG. 5( d ) , Tag- 1  of a first chip A, disposed on the bottom layer being one of a passive substrate or an active substrate, and Tag- 2  of a first chip B, disposed on the bottom layer, share a first WPT disposed in the bottom layer for parallel testing. A second chip A having a third tag is disposed on a second chip B having a fourth tag and a second WPT, and the third and the fourth tags share the second WPT. And, two test blocks, the fifth and the sixth tags of chip-C disposed on the bottom layer, share a third WPT for block parallel testing. There is also a fourth WPT disposed in the bottom layer and connected to the third WPT. 
     EMBODIMENTS 
     There is a method for wireless information access in a three-dimensional integrated circuit (3DIC) provided in the present disclosure. This proposed method includes steps of: 
     providing plural stacked chips including a wireless device, an information and a transmitting/receiving circuit; and 
     accessing wirelessly the information via the wireless device and the transmitting/receiving circuit during a packaging process for the plural stacked chips. In this embodiment, the wireless device is a wireless power transfer device (WPTD). 
     There is a testing method proposed in the present disclosure. This testing method includes steps of: 
     providing a semiconductor structure having a wireless chip; 
     wirelessly receiving a power by the wireless chip; and 
     using the power to test the semiconductor structure. In this embodiment, the wireless chip is a wireless power transfer device (WPTD). 
     There is a 3DIC provided in the present disclosure. This 3DIC includes 
     a semiconductor structure, and 
     a wireless power device (WPD) formed on the semiconductor structure for wirelessly receiving a power for operating a function selected from a group consisting of probing the semiconductor structure, testing the semiconductor structure and accessing a first information from the semiconductor structure. In this embodiment, the WPD is a wireless power transfer device (WPTD). 
     According to the aforementioned descriptions, the present disclosure provides a 3DIC having a wireless power device (WPD) for wirelessly receiving a power for operating a function selected from a group consisting of probing the semiconductor structure, testing the semiconductor structure and accessing an information from the semiconductor structure and a method thereof to avoid the ESD damage and the area penalty so as to possess the nonobviousness and the novelty. 
       FIG. 6  is a schematic diagram of a composite integrated circuit (IC)  600 , in accordance with some embodiments. Composite IC  600  is a semiconductor structure that includes a first circuit layer  610 , a second circuit layer  620 , and, in some embodiments, a third circuit layer  630 . Composite IC  600  also includes one or more wireless power devices (WPDs)  640  and one or more tracking circuits  650 . One or more WPDs  640  are electrically connected to one or more tracking circuits  650  through interconnection structures  660 . 
     In some embodiments, composite IC  600  is a 3DIC stacking similar to a 3DIC described above with respect to  FIG. 5( a ), 5( b ), 5( c ) , or  5 ( d ). In some embodiments, composite IC  600  is a package-on-package (PoP) structure. In some embodiments, composite IC  600  is a chip-on-wafer-on-substrate (CoWoS®) structure. In some embodiments, composite IC  600  is a fan-out wafer level chip scale package (FO-WLCSP) structure. In some embodiments, composite IC  600  is an integration FO-WLCSP package on-package (InFO-PoP) structure. In some embodiments, composite IC  600  is a fan-in wafer level chip scale package (FI-WLCSP) structure. In some embodiments, composite IC  600  is an under-bump-metallization (UBM)-free FI-WLCSP (UPI) structure. 
     First circuit layer  610  includes an IC chip, wafer, and/or substrate with at least one electrical circuit. In some embodiments, the at least one electrical circuit is an integrated circuit. In some embodiments, the at least one electrical circuit has only passive elements such as metal traces, bumps, and through-silicon vias (TSVs). 
     In some embodiments, first circuit layer  610  is a bottom layer described above with respect to  FIG. 5( a ), 5( b ), 5( c ) , or  5 ( d ). In some embodiments, first circuit layer  610  is a substrate. In some embodiments in which composite IC  600  is a chip on wafer on substrate (CoWoS®) structure, first circuit layer  610  is a wafer on a substrate. In some embodiments in which composite IC  600  is a FO-WLCSP or FI-WLCSP structure, first circuit layer  610  is a wafer. 
     In some embodiments, first circuit layer  610  includes a first circuit sub-layer  612 . If present, first circuit sub-layer  612  is a circuit component of first circuit layer  610 . In some embodiments, first circuit sub-layer  612  is an IC chip of first circuit layer  610 . In some embodiments, first circuit sub-layer  612  is an IC chip package of first circuit layer  610 . In some embodiments, first circuit sub-layer  612  is a substrate of first circuit layer  610 . In some embodiments, first circuit sub-layer  612  is a wafer of first circuit layer  610 . 
     In some embodiments, first circuit layer  610  includes a second circuit sub-layer  614 . If present, second circuit sub-layer  614  is a circuit component of first circuit layer  610 . In some embodiments, second circuit sub-layer  612  is an IC chip of first circuit layer  610 . In some embodiments, second circuit sub-layer  612  is an IC chip package of first circuit layer  610 . In some embodiments, second circuit sub-layer  612  is a substrate of first circuit layer  610 . In some embodiments, second circuit sub-layer  612  is a wafer of first circuit layer  610 . In some embodiments, first circuit layer  610  includes additional sub-layers (not shown). 
     Second circuit layer  620  includes at least one IC chip  622  or IC chip  624 . In some embodiments, second circuit layer  620  includes both IC chip  622  and IC chip  624 . In some embodiments, second circuit layer  620  includes both IC chip  622  and IC chip  624  and at least one additional IC chip (not shown). In some embodiments, one or more of IC chips  622  or  624  is a chip A, B, C, or D in contact with a bottom layer as described above with respect to  FIG. 5( a ), 5( b ), 5( c ) , or  5 ( d ). 
     In some embodiments, IC chip  622  is an IC chip package of second circuit layer  620 . In some embodiments, IC chip  624  is an IC chip package of second circuit layer  620 . 
     If present, third circuit layer  630  includes at least one IC chip  632  or IC chip  634 . In some embodiments, third circuit layer  630  includes both IC chip  632  and IC chip  634 . In some embodiments, third circuit layer  630  includes both IC chip  632  and IC chip  634  and at least one additional IC chip (not shown). In some embodiments, one or more of IC chips  632  or  634  is a chip A or E separated from a bottom layer by another chip as described above with respect to  FIG. 5( a ), 5( b ), 5( c ) , or  5 ( d ). 
     In some embodiments, IC chip  632  is an IC chip package of third circuit layer  630 . In some embodiments, IC chip  634  is an IC chip package of third circuit layer  630 . In some embodiments, third circuit layer  630  includes multiple sub-layers and each sub-layer includes one or more IC chips  632  and/or  634  as described above with respect to third circuit layer  630 . 
     In some embodiments, ICs of first circuit layer  610 , second circuit layer  620 , and, if present, third circuit layer  630  are resources from different processes (e.g., N40, N65). In some embodiments, ICs of first circuit layer  610 , second circuit layer  620 , and, if present, third circuit layer  630  are resources from different manufacturers. In some embodiments, ICs of first circuit layer  610 , second circuit layer  620 , and, if present, third circuit layer  630  are resources that are integrated based on functionality (e.g., central processing unit (CPU) and graphics processing unit (GPU)) or specified performance levels (e.g., speed and power consumption). 
     A WPD  640  is a WPT device such as an antenna, capacitor, inductor, or other interface capable of extracting energy from an electromagnetic signal and generating a power supply voltage. 
     Composite IC  600  includes at least one WPD  640  either in first circuit layer  610  or in second circuit layer  620 , as depicted in  FIG. 6 . Each WPD  640  is a wireless power device configured to receive and/or transmit data in accordance with radio-frequency identification (RFID), WiFi, 802.11, Bluetooth, ZigBee, near-field communication (NFC), or other wireless standards. In some embodiments, one or more WPD  640  is a WPT device as described above with respect to  FIG. 4 . 
     In some embodiments, composite IC  600  includes at least one WPD  640  in each of first circuit layer  610  and second circuit layer  620 . In some embodiments, composite IC  600  includes one or more WPDs  640  in third layer  630 , if present. 
     In some embodiments, composite IC  600  includes a WPD  640  in first sub-layer  612 . In some embodiments, composite IC  600  includes a WPD  640  in first sub-layer  612  and at least one additional WPD  640  in at least one additional sub-layer of first circuit layer  610  (not shown). 
     In some embodiments, composite IC  600  includes a WPD  640  in IC chip  622 . In some embodiments, composite IC  600  includes a WPD  640  in IC chip  622  and at least one additional WPD  640  in at least one additional IC chip (not shown) of second circuit layer  620 . 
     In some embodiments, composite IC  600  includes a WPD  640  in IC chip  632 . In some embodiments, composite IC  600  includes a WPD  640  in IC chip  632  and at least one additional WPD  640  in at least one additional IC chip (not shown) of third circuit layer  630 . 
     Composite IC  600  includes at least one tracking circuit  650  either in first circuit layer  610  or in second circuit layer  620 , as depicted in  FIG. 6 . A tracking circuit is a circuit capable of receiving a power supply voltage and responding to an instruction extracted from an electromagnetic signal by storing and/or outputting tracking data. Tracking data are data related to one or more components of the composite IC. In some embodiments, tracking data are data related to chip or IC identification, origin, performance, function, or test results. 
     In some embodiments, a tracking circuit is configured to be capable of executing a circuit test in response to an instruction extracted from an electromagnetic signal and to store and/or output test result data as tracking data. In some embodiments, a tracking circuit is configured to be capable of executing a circuit test in response to an instruction extracted from an electromagnetic signal and to store and/or output test result data indicative of circuit speed or power consumption as tracking data. 
     In some embodiments, one or more tracking circuits  650  is a circuit configured to extract instructions from electromagnetic signals conforming to RFID, WiFi, 802.11, Bluetooth, ZigBee, NFC, or other wireless standards. In some embodiments, one or more tracking circuits  650  is a tag as described above with respect to  FIG. 4 . 
     In some embodiments, composite IC  600  includes at least one tracking circuit  650  in each of first circuit layer  610  and second circuit layer  620 . In some embodiments, composite IC  600  includes one or more tracking circuits  650  in third layer  630 , if present. 
     In some embodiments, composite IC  600  includes a tracking circuit  650  in second sub-layer  614 . In some embodiments, composite IC  600  includes a tracking circuit  650  in second sub-layer  614  and at least one additional tracking circuit  650  in at least one additional sub-layer of first circuit layer  610  (not shown). 
     In some embodiments, composite IC  600  includes a tracking circuit  650  in IC chip  624 . In some embodiments, composite IC  600  includes a tracking circuit  650  in IC chip  624  and at least one additional tracking circuit  650  in at least one additional IC chip (not shown) of second circuit layer  620 . 
     In some embodiments, composite IC  600  includes a tracking circuit  650  in IC chip  634 . In some embodiments, composite IC  600  includes a tracking circuit  650  in IC chip  634  and at least one additional tracking circuit  650  in at least one additional IC chip (not shown) of third circuit layer  630 . 
     Interconnection structures  660  are sets of interconnection structures configured to provide electrical connections between one or more of WPDs  640  and one or more of tracking circuits  650 . Interconnection structures  660  include conductive elements located on one or more of first circuit layer  610 , second circuit layer  620 , and, if present, third circuit layer  630 . Non-limiting examples of conductive elements include metal lines, vias, TSVs, UBM structures, bumps, wires, and post-passivation structures. 
     In some embodiments, an interconnection structure of interconnection structures  660  is configured to provide electrical connections between a single WPD  640  and a single tracking circuit  650 . In some embodiments, an interconnection structure of interconnection structures  660  is configured to provide electrical connections between a single WPD  640  and multiple tracking circuits  650 . In some embodiments, an interconnection structure of interconnection structures  660  is configured to provide electrical connections between multiple WPDs  640  and a single tracking circuit  650 . In some embodiments, interconnection structure of interconnection structures  660  is configured to provide electrical connections between multiple WPDs  640  and multiple tracking circuits  650 . In some embodiments, interconnection structures  660  include an interconnection in a bottom layer as depicted in  FIG. 5( a ) . 
     In some embodiments, an interconnection structure of interconnection structures  660  is configured to provide electrical connections between a WPD and a tracking circuit on a same circuit layer. In some embodiments, an interconnection structure of interconnection structures  660  is configured to provide electrical connections between a WPD  640  and a tracking circuit  650  on different circuit layers. 
       FIG. 7  is a schematic diagram of a tracking circuit  700 , in accordance with some embodiments. Tracking circuit  700  is usable as a tag described above with respect to  FIG. 4  and/or as a tracking circuit  650  of composite IC  600  described above with respect to  FIG. 6 . 
     Tracking circuit  700  includes front end circuit  710 , digital controller  750 , and non-volatile memory (NVM)  790 . Front end circuit  710  includes 1/0 port  712 , demodulator  720 , AC/DC converter  730 , and modulator  740 . Digital controller  750  includes parser/decoder  760 , main control unit  770 , and encoder/framer  780 . Demodulator  720  is configured to provide a signal Data In to parser/decoder  760 , and encoder/framer  780  is configured to provide a signal Data Out to modulator  740 . Tracking circuit  700  is configured to deliver a DC power signal VDD and a power-on reset signal Reset from AC/DC converter  730  to main control unit  770 . Tracking circuit  700  is further configured to provide two-way communication between main control unit  770  and NVM  790 . 
     In some embodiments, front end circuit  710  is an RF/Analog front end as described above with respect to  FIG. 4 . In some embodiments, digital controller  750  is a digital controller as described above with respect to  FIG. 4 . In some embodiments, NVM  790  is an NVM as described above with respect to  FIG. 4 . 
     Front end circuit  710  is a circuit configured to receive an electromagnetic signal through 1/0 port  712 . The electromagnetic signal includes energy in the form of a power supply voltage or information in the form of a modulated signal. In some embodiments, front end circuit  710  is configured to receive the electromagnetic signal from one or more WPDs  640  of composite IC  600  described above with respect to  FIG. 6 . 
     Front end circuit  710  is further configured to output a modulated electromagnetic signal though 1/0 port  712 . In some embodiments, front end circuit  710  is configured to output the modulated electromagnetic signal to one or more WPDs  640  of composite IC  600  described above with respect to  FIG. 6 . 
     Demodulator  720  is a circuit configured to receive and demodulate the electromagnetic signal and output the demodulated electromagnetic signal as digital signal Data In. In some embodiments, demodulator  720  includes an envelope detector (not shown) configured to demodulate the electromagnetic signal and output signal Data In or a clock signal (not shown). 
     AC/DC converter  730  is a circuit configured to generate DC power signal VDD and power-on reset signal Reset based on the electromagnetic signal. In some embodiments, AC/DC converter  730  comprises a charge pump (not shown) configured to rectify the electromagnetic signal or a voltage regulator (not shown) configured to limit and regulate charge pump output to generate DC power signal VDD and power-on reset signal Reset. 
     Modulator  740  is a circuit configured to receive digital signal Data Out and generate a modulated electromagnetic signal based on signal Data Out. 
     Parser/decoder  760  is a circuit configured to decode received signal Data In and output parsed commands to main control unit  770 . In some embodiments, parser/decoder  760  includes separate decoder and parser circuits (not shown). 
     Main control unit  770  is a circuit configured to control operations of digital controller  750  by receiving DC power VDD and power-on reset signal Reset, and executing parsed commands to communicate with NVM  790  and output replied data to encoder/framer  780 . In some embodiments, main control unit  770  includes a power management circuit (not shown) configured to control power consumption. In some embodiments, main control unit  770  includes a main state machine (not shown) configured to process and execute the parsed commands and to communicate with NVM  790 . 
     In some embodiments, main control unit  770  is further configured to execute one or more circuit tests. In some embodiments, main control unit  770  includes electrical connections (not shown) to one or more circuits separate from tracking circuit  700  for executing the circuit tests. In some embodiments, main control unit  770  is further configured to power execution of one or more circuit tests using VDD. In some embodiments, main control unit  770  is further configured to execute one or more circuit tests to measure speed or power consumption. 
     Encoder/framer  780  is a circuit configured to encode frame data as digital signal Data Out. In some embodiments, encoder/framer  780  includes separate framer and encoder circuits (not shown). 
     NVM  790  is configured to store and retrieve data used by tracking circuit  700 . In some embodiments, data stored in and retrieved from NVM  790  is test result data from one or more tests executed by main control unit  770 . 
       FIG. 8  is a schematic diagram of a wireless communication system  800 , in accordance with some embodiments. Wireless communication system  800  includes a composite IC  810  and a wireless communication device  820  configured to communicate via an electromagnetic signal  830 . In various embodiments, wireless communication system  800 , composite IC  810 , wireless communication device  820 , and electromagnetic signal  830  are configured to communicate based on RFID, WiFi, 802.11, Bluetooth, ZigBee, NFC, or other wireless standards. 
     Composite IC  810  includes one or more WPDs configured to receive and transmit wireless signal  830 . In some embodiments, composite IC  810  is composite IC  600  and the one or more WPDs is one or more WPDs  640  of composite IC  600 . In some embodiments, composite IC is a 3DIC stacking described above with respect to  FIG. 5( a ), 5( b ), 5( c ) , or  5 ( d ). 
     Wireless communication device  820  is a communication device configured to communicate wirelessly. In some embodiments, wireless communication device  820  is a wireless tracking device. In some embodiments, wireless communication device  820  is a handy reader described above with respect to  FIG. 1 . 
     In some embodiments, wireless communication device  820  is electrically connected to one or more storage devices (not shown) and is further configured to store data retrieved from composite IC  810  via electromagnetic signal  830  in the one or more storage devices. In some embodiments, wireless communication device  820  is electrically connected to one or more storage devices (not shown) and is further configured to transmit data or commands from the one or more storage devices to composite IC  810  via electromagnetic signal  830 . 
       FIG. 9  is a flow chart of a method  900  of accessing a semiconductor structure, in accordance with some embodiments. Method  900  is usable in conjunction with a wireless communication system, e.g., wireless communication system  800 . In some embodiments, the semiconductor structure is a composite IC, e.g., composite IC  600 . 
     Method  900  includes operation  910 , in which a WPT device of a semiconductor structure generates a power supply voltage by extracting energy from an electromagnetic signal. In some embodiments, the WPT device is part of a WPD  640  of composite IC  600 . In some embodiments, the electromagnetic signal is electromagnetic signal  830  of wireless communication system  800 . 
     Method  900  continues at operation  920 , in which the power supply voltage is transmitted from the WPT device to a tracking circuit in a first chip of the semiconductor structure by an interconnection structure of the semiconductor structure. In some embodiments, the tracking circuit is a tracking circuit  650  of composite IC  600 . In some embodiments, the tracking circuit is a tracking circuit  700 . 
     In some embodiments, the power supply voltage is transmitted by an interconnection structure of interconnection structures  660  of composite IC  600 . In some embodiments, the power supply voltage is transmitted from a second chip of the semiconductor structure. In some embodiments, the WPT device is in a first circuit layer of the semiconductor structure, the first chip is in a second circuit layer of the semiconductor structure, and the power supply voltage is transmitted from the first circuit layer of the semiconductor structure to the second circuit layer of the semiconductor structure. 
     Method  900  continues at operation  930 , in which the tracking circuit is powered with the power supply voltage from the WPT device. In some embodiments, the tracking circuit is powered using a front end circuit  710  of tracking circuit  700 . 
     Method  900  continues at operation  940 , in which the tracking circuit accesses tracking data of the first chip of the composite IC in response to an instruction extracted from the electromagnetic signal. In some embodiments, the tracking data are accessed from a memory circuit in the tracking circuit. In some embodiments, the tracking data are accessed from an NVM  790 . 
     In some embodiments, the tracking data are data related to chip or IC identification (ID), origin, performance, function, or test results. In some embodiments, accessing tracking data includes outputting the tracking data from the tracking circuit to the WPT device. In some embodiments, the tracking circuit accesses tracking data using digital controller  750  of tracking circuit  700 . 
     In some embodiments, method  900  includes operations in addition to operations  910  through  940  for accessing tracking data. In various embodiments, additional operations include execution of one or more tests on the semiconductor device in which one or more tracking devices are located, and storing tracking data including test results of the one or more tests. 
     In some embodiments, method  900  continues at operation  950 , in which one or more tests are executed on the semiconductor structure. In some embodiments, executing the one or more tests includes outputting a test result from the tracking circuit to the WPT device. In some embodiments, at least one of the one or more tests is executed within the chip or IC in which the WPT device is located. In some embodiments, at least one of the one or more tests is executed outside the chip or IC in which the WPT device is located and within the semiconductor structure. 
     In some embodiments, the one or more the tests include determining a speed of a circuit. In some embodiments, the one or more tests include determining a power consumption of a circuit. In some embodiments, the tracking circuit executes the one or more tests using digital controller  750  of tracking circuit  700 . 
     In some embodiments, a first test of the one or more tests is performed by a first tracking circuit and a second test of the one or more tests is performed by a second tracking circuit separate from the first tracking circuit. In some embodiments, the first tracking circuit and the second tracking circuit are on the first chip. In some embodiments, the first tracking circuit is on the first chip and the second tracking circuit is on a second chip. 
     In some embodiments, method  900  continues at operation  960 , in which a test result is stored by the tracking circuit. In some embodiments, the test result is stored in a memory circuit in the tracking circuit. In some embodiments, the test result is stored in an NVM  790 . In some embodiments, the test result is the result of a test prior to execution of method  900 . In some embodiments, the test result is the result of a test performed in operation  950  of method  900 . 
     In some embodiments, method  900  includes additional operations in which accessed tracking data are used for making decisions related to assembling a semiconductor structure. In various embodiments, accessed tracking data are used for matching characteristics of chips added to a semiconductor structure to characteristics of chips already present in the semiconductor structure. 
     In some embodiments, method  900  continues at operation  970 , in which a second chip is selected for the semiconductor structure based on the accessed tracking data. In various embodiments, the second chip is selected based on the accessed tracking data comprising one or more of an IC or chip ID, origin, performance, function, or result of one or more tests. In some embodiments, the second chip is selected based on accessed tracking data comprising a result of a test performed in operation  950  of method  900 . In some embodiments, the second chip is selected based on accessed tracking data comprising results of more than one test performed in accordance with operation  950  of method  900 . 
     In some embodiments, the second chip is selected based on circuit speed information contained in the accessed tracking data. In some embodiments, the second chip is selected based on circuit power consumption information contained in the accessed tracking data. In some embodiments, the second chip is selected based on binning information contained in the accessed tracking data. 
     In some embodiments, the second chip is a chip in a chip package. In some embodiments, the second chip is a chip of a plurality of chips, each of which is selected based on accessed tracking data. 
     In some embodiments, a composite IC comprises a first circuit layer, a second circuit layer comprising a first chip and a second chip, and a first WPT device in the first chip or the first circuit layer. The first WPT device is configured to generate a power supply voltage by extracting energy from an electromagnetic signal. A first tracking circuit in the second chip or the first circuit layer is configured to be powered by the power supply voltage from the first WPT device and to store or output tracking data in response to an instruction extracted from the electromagnetic signal. 
     In some embodiments, a method of accessing a composite IC comprises generating, by a WPT device of the composite IC, a power supply voltage by extracting energy from an electromagnetic signal, transmitting the power supply voltage from the WPT device to a first chip of the composite IC, and powering a tracking circuit in the first chip is with the power supply voltage. The method further comprises accessing, by the tracking circuit, tracking data of the first chip of the composite IC in response to an instruction extracted from the electromagnetic signal. 
     In some embodiments, a method of testing a semiconductor structure comprises causing a WPT device of the semiconductor structure to generate a power supply voltage by extracting energy from an electromagnetic signal and causing, by using a tracking circuit embedded in a first chip of the semiconductor structure, the semiconductor structure to execute a test of the semiconductor structure, the test being powered by the power supply voltage from the WPT device. The WPT device is embedded in a portion of the semiconductor structure other than the first chip of the semiconductor structure. 
     While the disclosure has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. Therefore, the above description and illustration should not be taken as limiting the scope of the present disclosure which is defined by the appended claims. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.