Examination of Heatsinking in Thermally Multiplexed TES Arrays With Buried Wiring

It is now possible to fabricate stacks of buried wires with extremely high density, perfect yield, and many layers using fine-line lithography and chemical mechanical polish. Such wiring in principle will enable large format arrays of fine pitch sensors. Buried wiring has the distinct advantage that additional metallization – such as metallic links in a thermal multiplexer (“hydra”) design and attachment points between absorbers and the substrate – are not limited in their placement. In close-packed arrays, thermal crosstalk occurs when a heat pulse in one device transmits through the dielectric connection and is absorbed in a neighbor. We seek to integrate Mo/Au transition edge sensors with such wiring but encounter limitations of fabrication options by the restriction of materials permitted to be used, including noble metals and certain dielectrics. In this paper we show measurement results of X-ray microcalorimeters with multi-stack buried wiring on a silicon nitride dielectric layer exploring new methods of integrating heat sinking. We attempt to mitigate thermal crosstalk channels by enhancing coupling of the emitted heat to a thick metallic heatsinking layer. We measure the thermal response in close packed hydra arrays in a variety of heatsinking configurations and show energy resolution and pulse response in these devices.