Integration of Through-Sapphire Substrate Machining with Superconducting Quantum Processors

Area of Science:

• Quantum Computing
• Materials Science
• Microfabrication

Background:

• High-coherence qubits are essential for fault-tolerant quantum computers.
• Sapphire substrates support high-coherence qubits due to their low-loss dielectric properties.
• Current limitations in sapphire processing restrict quantum processors to small scales or chiplet architectures.

Purpose of the Study:

• To demonstrate a sapphire machining process compatible with high-coherence qubits.
• To enable through-substrate electrical connections and signal routing in sapphire-based quantum processors.
• To facilitate the scaling of quantum processing units (QPUs) using sapphire.

Main Methods:

• Development of a specialized sapphire machining technique.
• Integration of the machining process with intermediate-scale quantum processors.
• Demonstration of through-substrate electrical connections for mode-mitigation and signal routing.

Main Results:

• The demonstrated machining process is compatible with high-coherence qubits.
• Through-substrate electrical connections were successfully achieved in sapphire.
• The technique provides a pathway for scaling sapphire-based quantum processing units.

Conclusions:

• The developed sapphire machining process overcomes previous limitations in scaling quantum processors.
• This advancement allows for integrated mode-mitigation and signal routing in larger sapphire QPUs.
• The process enables the use of sapphire-compatible materials for large-scale quantum computing applications.