The ever-increasing demand for greater IT security, higher and faster computing power and data transmission are driving the further development of information and communication technology and industrial applications. These require high reliability and measurement accuracy. Sensors based on quantum technology can better meet these requirements and are used, for example, in quantum cryptography, fluorescence microscopy or light-based object detection and distance measurement (LIDAR). Superconducting nanowire single photon detectors (SNSPD), which also have a very high detection sensitivity, are predominantly used here. For everyday use, these systems still require a great deal of development work, including the miniaturization of the control and readout units as well as adapted assembly and connection technology.
Corresponding miniaturization can be achieved through the 2.5D and 3D integration of sensor elements to implement the most space-saving package possible with a high integration density. The new research project SAIn (Self-adjusting cryogenic Indium Interconnection) pursues the goal of a self-aligning chip level package with an alignment accuracy of ±1µm and better. It includes the development of the electroplating process for indium deposition to produce the indium contacts and the reflow process for remelting the deposited indium columns into indium bumps. The technological developments pursued here provide the basis for creating arrays of fiber-coupled SNSPDs in a compact design for a wide range of applications, for example in medical diagnostics.
The research and development work described was funded by the Federal Ministry for Economic Affairs and Climate Action (BMWK) as part of the “Self-adjusting cryogenic Indium Interconnection” (SAIn) research project.
Funding code: 49VF240014