Method of and sensing probe device for measuring a parameter of a quantum chip

A probe station for measuring a parameter of a quantum chip, the quantum chip comprising a quantum device and at least one probe pad in conductive contact with the quantum device, wherein the probe station comprises one or more sensing probe devices, wherein the or each sensing probe device is mountable to an actuator for enabling the sensing probe device to engage contact with a contact surface of the at least one probe pad, wherein the sensing probe device is configured for enabling measuring, using the sensing probe device in contact with the probe pad, the parameter of the quantum device;

• wherein the sensing probe device, for contacting the contact surface, comprises at least two probe tips which are electrically separated from each other,
• wherein each of the at least two probe tips is electrically connected separately such to convey an electrical signal thereto, for enabling measuring a contact impedance between the at least two electrically separated probe tips when said probe tips are in contact with the contact surface,
• wherein the probe station comprises or is configured for operatively connecting to a data acquisition system for processing measurements obtained by said measuring, and
• wherein the probe station comprises a controller, a memory and one or more actuators operated by the controller and configured for operating the one or more sensing probe devices for performing a method of measuring a parameter of a quantum chip using at least one sensing probe device, the quantum chip comprising a quantum device and at least one probe pad in conductive contact with the quantum device for enabling the measuring, wherein the method comprises:
• engaging contact between the at least one sensing probe device and a contact surface of the probe pad;
• and
• measuring, using the sensing probe device in contact with the probe pad, the parameter of the quantum device;
• wherein the sensing probe device comprises at least two probe tips, wherein the at least two probe tips are electrically separated from each other, and wherein prior to the measuring the parameter of the quantum device and after the engaging contact, the method comprises conductance testing and conditional surface conditioning of the contact surface, wherein the conductance testing and conditional surface conditioning of the contact surface comprises:
• measuring a contact impedance between the at least two electrically separated probe tips, the at least two electrically separated probe tips being in contact with the contact surface;
• determining, based on the measured contact impedance, whether the contact impedance is sufficient for enabling the measuring of the parameter of the quantum device;
• and
• performing, in accordance with determining that the contact impedance is insufficient, surface conditioning on the contact surface of the probe pad for lowering the contact impedance.