Neocera, Inc.

Northrop Grumman Systems Corporation

Microsoft Technology Licensing, LLC

Solid State Measurements, Inc.

University System of Maryland

Vladimir Vladimirovich Talanov

Andrew R Schwartz

Robert L Moreland

Hans M Christen

Quentin P Herr

Anna Y Herr

Joshua A Strong

Andre Scherz

Antonio Orozco

Alfred Benjamin Cawthorne, Iii

Max Earl Nielsen

Jonathan D Egan

Steven Mark Anlage

Nicholas Eric Gagliolo

Temitope Olumuyiwa Ogunnika

Nesco Mario Lettsome, Jr

Edward Rudman

Stacked superconducting integrated circuits with three dimensional resonant clock networks are described. An apparatus, including a first superconducting integrated circuit having a first clock distribution network for distributing a first clock signal in the first superconducting integrated circuit, is provided. The apparatus further includes a second superconducting integrated circuit, stacked on top of the first superconducting integrated circuit, having a second clock distribution network for distributing a second clock signal in the second superconducting integrated circuit, where each of the first clock distribution network and the second clock distribution network comprises a clock structure having a plurality of unit cells, where each of the plurality of unit cells includes at least one spine and at least one stub, the at least one stub inductively coupled to a first superconducting circuit, and where each of the first clock signal and the second clock signal has a same resonant frequency.

Stacked superconducting integrated circuits with three dimensional resonant clock networks

Superconducting integrated circuit layouts are proofed against the detrimental effects of stray flux by designing and fabricating them to have one or more ground planes patterned in the x-y plane with a regular grid of low-aspect-ratio flux-trapping voids. The ground plane(s) can be globally patterned with such voids and thousands or more superconducting circuit devices and wires can thereafter be laid out so as not to intersect or come so close to the voids that the trapped flux would induce supercurrents in them, thus preventing undesirable coupling of flux into circuit elements. Sandwiching a wire layer between patterned ground planes permits wires to be laid out even closer to the voids. Voids of successively smaller maximum dimension can be concentrically stacked in pyramidal fashion in multiple ground plane layers having different superconductor transition temperatures, increasing the x-y area available for device placement and wire-up.

Superconductor ground plane patterning geometries that attract magnetic flux

One embodiment includes a clock distribution resonator system. The system includes a clock source configured to generate a clock signal having a predefined wavelength, and a main transmission line coupled to the clock source to propagate the clock signal and comprising a first predetermined length defined as a function of the wavelength of the clock signal. The system also includes a plurality of transmission line branches each coupled to the main transmission line to propagate the clock signal. Each of the plurality of transmission line branches includes a second predetermined length different from the first predetermined length. The system further includes a plurality of clock distribution networks coupled to the respective plurality of transmission line branches and being configured to provide the clock signal to each of a plurality of circuits to provide clock synchronization for the associated plurality of circuits.

Clock distribution resonator system

One example includes a superconducting transmission driver system. The system includes a latching gate stage comprising at least one Josephson junction configured to switch from an off state to an oscillating voltage state to provide an oscillating voltage at a control node in response to a single flux quantum (SFQ) pulse received at an input. The system further includes a low-pass filter stage coupled to the control node and configured to convert the oscillating voltage to a pulse signal to be transmitted over a transmission line.

Superconducting transmission driver system

A superconducting integrated circuit including a clock distribution network for distributing a clock signal in the superconducting integrated circuit is provided. The clock distribution network may include a clock structure having unit cells, where each of the unit cells may include at least one spine and at least one stub. The clock structure may further include at least one spine connected to the at least one stub, where the at least one stub may further be inductively coupled to at least one superconducting element. The clock signal may have a wavelength. Each of the unit cells may be spaced apart from each other along the clock structure by a distance, where the distance may be less than one tenth of the wavelength.

Clock distribution network for a superconducting integrated circuit

Non-destructive localization of open defects in electronic devices is performed with a DC SQUID based RF magnetometer capable of sensing coherent magnetic fields up to 200 MHz and higher. RF magnetic fields (or RF current) images are correlated to conductive paths layout of the electronic device, and the open defect is pinpointed at a location of RF current disappearance on the current image. The bandwidth limitations associated with transmission line delays between SQUID circuit and readout electronic, as well as with near-field coupling between different parts of the measurement scheme, are overcome by superimposing the RF flux emanating from device under study on the modulation flux to produce at the SQUID output a binary phase modulated RF voltage, which is processed to lock the static flux, and to control modulation regime by producing an AC bias for the RF flux. RF readout electronics is based on a double lock-in through sequential demodulation of the RF component of the output SQUID voltage at the modulation flux frequency &#x3c9;and the RF flux frequency &#x3c9;.

Method and system for localization of open defects in electronic devices with a DC squid based RF magnetometer

An RF DC SQUID based magnetometer capable of sensing coherent magnetic fields up to 200 MHz and higher is developed which overcomes frequency limitations associated with noise signals due to transmission line delays between the SQUID circuit and readout electronics. The bandwidth limitations are overcome by superimposing the RF flux on the modulation flux to produce at the SQUID output a binary phase modulated RF voltage, which is processed to lock the static flux, and to control modulation regime by producing an AC bias for the RF flux. RF readout electronics based on a double lock-in technique (sequential demodulation of the RF SQUID voltage at the modulation flux frequency &#x3c9;and the RF flux frequency &#x3c9;), yields a signal proportional to the product of amplitude and phase cosine of RF flux with linear dynamic range up to five orders in magnitude if compared to DC SQUID operated in traditional flux-locked loop regime.

DC SQUID based RF magnetometer operating at a bandwidth of 200 MHz and higher

By using techniques for near field probes to measure dielectric values of blanket films, the measure of the sidewall damage of the patterned structure is calculated. The interaction between the near field probe and the etched structure is modeled to obtain the model total capacitance. The near field microwave probe is calibrated on a set of blanket films with different thicknesses, and the dielectric constant of the etched trench structure is calculated using the measured frequency shift and calibration parameters. The measured capacitance is further calculated for the etched trench structure using the dielectric constant and the total thickness of the etched trench structure. The effective dielectric constant of the structure under study is extracted where the model capacitance is equal to the measured capacitance. The measure of the sidewall damage is further calculated using the effective dielectric constant.

Method and system for measurement of sidewall damage in etched dielectric structures using a near field microwave probe

A measurement technique based on a microwave near-field scanning probe is developed for non-contact measurement of dielectric constant of low-k films. The technique is non-destructive, non-invasive and can be used on both porous and non-porous dielectrics. The technique is based on measurement of resonant frequency shift of the near-field microwave resonator for a plurality of calibration samples vs. distance between the probe tip and the sample to construct a calibration curve. Probe resonance frequency shift measured for the sample under study vs. tip-sample separation is fitted into the calibration curve to extract the dielectric constant of the sample under study. The calibration permits obtaining a linear calibration curve in order to simplify the extraction of the dielectric constant of the sample under study.

Method and system for measurement of dielectric constant of thin films using a near field microwave probe

A method and system for non-contact measurements of microwave capacitance of miniature structures patterned on wafers used for production of modern integrated circuits. A near-field balanced two-conductor probe is brought into close proximity to a test key built on a wafer of interest and replicating the miniature structure of interest. The resonant frequency of the probe for the test key is measured. The probe is then positioned at the same distance from an 'open' calibration key and 'short' calibration key, and the resonance frequencies of the probe for the calibration keys are measured. A shear force distance control mechanism maintains the distance between the tip of the probe and the measured test key and calibration keys. The microwave capacitance of the test key is then calculated in accordance with a predefined formula. The obtained microwave capacitance of the test key is indicative of the capacitance of the miniature structure of interest and may be further used for determining possible defects of the integrated circuit of interest.

Method and system for non-contact measurement of microwave capacitance of miniature structures of integrated circuits

A probe for non-destructive determination of complex permittivity of a material and for near field optical microscopy is based on a balanced multi-conductor transmission line structure created on a dielectric substrate member which confines the probing field within a sharply defined sampling volume in the material under study. A method for manufacturing dielectric support member based probes includes anisotropically depositing a 50-100 &#x212b; thick underlayer of Cr, Ni, W or Ta onto the dielectric support member, anisotropically depositing conductive material onto the Cr, Ni, W or Ta underlayer, and removing the unwanted conductive material at the sides of the dielectric support member to electrically isolate the created conductive strips.

Apertured probes for localized measurements of a material's complex permittivity and fabrication method

In the method and system for non-contact measurements of microwave capacitance of test structures patterned on wafers used for production of modern integrated circuits, a near-field balanced two-conductor probe is brought into close proximity to a test structure, and the resonant frequency of the probe for the test structure is measured. The probe is then positioned at the same distance from the uniform metallic pad, and the resonance frequency of the probe for the uniform metallic pad is measured. A shear force distance control mechanism maintains the distance between the tip of the probe and the metallic pad equal to the distance between the tip of the probe and the test structure. The microwave capacitance of the test structure is then calculated in accordance with a predefined formula. The obtained microwave capacitance may be further used for determining possible defects of the test structure.

A method for measuring a material's complex permittivity is provided where a near-field microwave probe is positioned a predetermined distance from a first and a second standard sample for measuring a relative resonant frequency shift of the near-field microwave probe for standard samples. Based on measurements, calibration coefficients are calculated. A relative resonant frequency shift of the near-field microwave probe for a sample under study is measured by fast frequency sweep technique while the distance between the tip of the probe and the sample under the study is maintained nominally at the distance between the tip of the probe and each standard sample during a calibration procedure by a shear-force based distance control mechanism. Also, the change in the quality factor of the probe for unloaded and loaded resonator is measured. The dielectric constant of the sample under study is calculated using the resonant frequency shift and the change in the quality factor of the near-field microwave probe for the sample under study and the calibration coefficients obtained during the calibration procedure.

System and method for quantitative measurements of a material's complex permittivity with use of near-field microwave probes

A probe for non-destructive determination of complex permittivity of a material and for near field optical microscopy is based on a balanced multi-conductor transmission line structure created on a dielectric substrate member which confines the probing field within a sharply defined sampling volume in the material under study.

An apparatus for localized measurements of complex permittivity of a material is provided. A probe ( ) analyzes the complex permittivity of a sample ( ), the probe ( ) having a balanced two conductor transmission line ( ) formed of conductive segments ( and ). A probing end ( ) of the transmission line ( ) is brought within close proximity of sample ( ) and an opposite end ( ) of the transmission line is connected to a terminating plate ( ) to form a resonator structure ( ) for measurement of the complex permittivity of sample ( ).

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Ellicott City, MD, United States of America

Vladimir Vladimirovich Talanov