Superconducting bump bond electrical characterization

US10950778B2 · kind B2 · utility

Assignee

• NORTHROP GRUMMAN SYSTEMS CORPORATION · US

Inventors

• Aurelius L. Graninger · Sykesville, US
• Joel D. Strand · Ellicott City, US
• Micah John Atman Stoutimore · Kensington, US
• Zachary Kyle Keane · Baltimore, US
• Jeffrey David Hartman · Severn, US
• JUSTIN C. HACKLEY · Catonsville, US

Key dates

• Filing date: Jan 7, 2019
• Grant date: Mar 16, 2021
• Expiry date: Jan 7, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/1423
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Test structures and methods for superconducting bump bond electrical characterization are used to verify the superconductivity of bump bonds that electrically connect two superconducting integrated circuit chips fabricated using a flip-chip process, and can also ascertain the self-inductance of bump bond(s) between chips. The structures and methods leverage a behavioral property of superconducting DC SQUIDs to modulate a critical current upon injection of magnetic flux in the SQUID loop, which behavior is not present when the SQUID is not superconducting, by including bump bond(s) within the loop, which loop is split among chips. The sensitivity of the bump bond superconductivity verification is therefore effectively perfect, independent of any multi-milliohm noise floor that may exist in measurement equipment.