Cryogenic Integration for Quantum Computer Using Diamond Color Center Spin Qubits

Toshiki Iwai, Kenichi Kawaguchi, Tetsuya Miyatake, Tetsuro Ishiguro, Shoichi Miyahara, Yoshiyasu Doi, Salahuddin Nur, Ryoichi Ishihara, Shintaro Sato

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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For quantum computing modules using diamond color centers, we propose an integrated structure of a quantum chip with photonic circuits and an interposer with electric circuits. The chip and interposer are connected via gold stud bumps using flip-chip bonding technology. For evaluating the proposed integrated structure, we bonded a test chip of 15 × 15 mm2, corresponding to the area that allows the allocation of color center qubits in the order of 102, with an interposer of 20 × 20 mm2, including test measurement lines. We confirm all connections of 16 lines with two bumps for each line at 10 K. The resistance of the lines with two bumps at 10 K is ~ 3.5O, These resistances are mainly attributed to the gold lines on the interposer, which is confirmed by simulations. The shear strength of the flip-chip bonded structure is 67 g/bump. It is larger than that of previous reports where the chips passed the standard temperature cycle test. Moreover, we integrate the flip-chip bonded structure with a printed circuit board (PCB). We confirm a connection between the connector terminal of the PCB and the test chip at 80 K. It is shown that the integrated structure using gold stud bumps has a potentially highly reliable connection at cryogenic temperature. These results will lead to realizing large-scale diamond spin quantum processors.

Original languageEnglish
Title of host publicationProceedings - IEEE 73rd Electronic Components and Technology Conference, ECTC 2023
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages6
ISBN (Electronic)9798350334982
Publication statusPublished - 2023
Event73rd IEEE Electronic Components and Technology Conference, ECTC 2023 - Orlando, United States
Duration: 30 May 20232 Jun 2023

Publication series

NameProceedings - Electronic Components and Technology Conference
ISSN (Print)0569-5503


Conference73rd IEEE Electronic Components and Technology Conference, ECTC 2023
Country/TerritoryUnited States

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.


  • Cryogenic integration
  • Diamond color center
  • Flip-chip bonding
  • Quantum computer


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