Vacuum-Sealed Qubit Packaging for Coherence Time Preservation

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Solution Overview

Problem

Existing quantum operation devices face challenges in maintaining the coherence time of qubit elements due to adsorbates adsorbed on the surface, which are not effectively addressed by existing technologies.

Innovation Solution

A quantum operation device configuration that includes a vacuum-sealed space around the qubit element, using superconducting materials for the cover and substrates, and integrating through-vias and conductive films to maintain a clean surface and suppress adsorption, thereby preserving the coherence time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cap layer is bonded to a substrate to form a sealed vacuum cavity, then the qubit element is protected from environmental adsorbates, but the coherence time is still reduced due to adsorbates that penetrate or remain on the qubit surface

Engineering Contradiction:

Improvecoherence timeVSAvoidadsorbate adsorption

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies vacuum sealing to create an inert environment around the qubit element. By bonding a cap layer to the substrate to form a sealed vacuum cavity, the qubit element is isolated from atmospheric adsorbates that would otherwise degrade coherence time. The vacuum environment prevents adsorbate adsorption on the qubit surface, directly addressing the harmful effect while maintaining reliability.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent introduces a sacrificial layer that is intentionally designed to be removed after serving its protective function during manufacturing. This disposable layer protects the qubit element during fabrication and bonding processes, then is selectively removed to expose the qubit surface for subsequent vacuum sealing, eliminating the need for complex in-situ surface treatment.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If the qubit element surface is exposed during manufacturing, then integration with wiring and control elements can be performed, but the surface becomes contaminated with adsorbates that reduce coherence time

Engineering Contradiction:

Improveintegration processVSAvoidcoherence time

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary protective action by forming a sacrificial layer over the qubit element before manufacturing processes begin. This layer pre-provides surface protection during fabrication and bonding operations. After integration is complete, the sacrificial layer is removed and vacuum sealing is applied, ensuring the qubit surface remains clean throughout the manufacturing process while enabling ease of integration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sacrificial layer acts as an intermediary protective barrier between the qubit element surface and the manufacturing environment. It mediates the conflict between needing surface exposure for manufacturing and needing surface protection for coherence, allowing manufacturing to proceed while the surface remains protected, then is removed to enable vacuum sealing.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Area of stationary object

If the device is miniaturized with high-density integration, then the footprint is reduced, but the qubit element becomes more susceptible to interference and adsorbate effects

Engineering Contradiction:

Improvedevice footprintVSAvoidcoherence time

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent applies vacuum sealing to create an inert environment that protects the qubit element from adsorbates. This is particularly important for miniaturized devices where the qubit element has smaller surface area and is more vulnerable to adsorbate effects. The sealed vacuum cavity isolates the compact qubit structure from environmental degradation, maintaining coherence time despite the reduced scale and increased susceptibility.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The vacuum-sealed configuration effectively prevents adsorbate adsorption, maintaining the coherence time of qubit elements and enabling high-density integration of qubit elements and wiring, contributing to the miniaturization of the device.

Implementation Method 1

adsorbates adsorbed on the surface

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

vacuum-sealed space around the qubit element

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 3

using superconducting materials for the cover and substrates

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentUS20260082822A1Quantum operation device and method of manufacturing quantum operation device

Publication Date: 2026.03.19 FUJITSU LTD

AI summary

A quantum operation device (10) includes: a first substrate (30) that has a through-hole (32A, 32B); a qubit element (20) formed at a first surface (S1) of the substrate (30); a cover (50) that covers a side of the first surface (S1) of the first substrate (30); and a second substrate (40) that is provided on a side of a second surface (S2) opposite to the side of the first surface (S1) of the first substrate (30) and that closes an open end of the through-hole (32A, 32B) on the side of the second surface (S2). A sealed space (51) that surrounds the qubit element (20) and communicates with the through-hole (32A, 32B) is provided between the first surface (S1) and the cover (50).