Thin-Film Components Integrated Onto Flex Circuit Boards

A quantum computing system comprising:

• a plurality of qubits;
• a quantum logic circuit configured to perform one or more quantum operations on the plurality of qubits;
• and
• a signal line assembly comprising:
• a flex circuit board comprising:
• at least one first ground layer;
• at least one first dielectric layer disposed on an inner surface of the at least one first ground layer, the first dielectric layer having a first thickness;
• and
• a plurality of first signal lines disposed on an inner surface of the at least one first dielectric layer;
• wherein the flex circuit board comprises at least one cutout section;
• and
• at least one film structure disposed in the cutout section, the film structure comprising:
• at least one second ground layer;
• at least one second dielectric layer having a second thickness that is smaller than the first thickness;
• and
• a plurality of second signal lines respectively coupled to the plurality of first signal lines.

A method for fabricating a signal line assembly, comprising:

• fabricating a flex circuit board comprising:
• at least one first ground layer;
• at least one first dielectric layer disposed on an inner surface of the at least one first ground layer, the first dielectric layer having a first thickness;
• and
• a plurality of first signal lines disposed on an inner surface of the at least one first dielectric layer;
• wherein the flex circuit board comprises at least one cutout section;
• fabricating a film structure comprising:
• at least one second ground layer;
• at least one second dielectric layer having a second thickness that is smaller than the first thickness;
• and
• a plurality of second signal lines respectively coupled to the plurality of first signal lines;
• applying one or more bump bonds to the flex circuit board;
• and
• coupling the film structure to the flex circuit board via the one or more bump bonds.