Fabricating a microelectronics grade metal substrate comprises forming the metal substrate on a sacrificial substrate. An adhesion layer can be deposited on or over the surface of the sacrificial substrate. A seed layer of the metal can be deposited on or over the adhesion layer. The metal material can be deposited on the seed layer by electroplating or other low-temperature, low-stress process to form a microelectronics-grade metal substrate. Thin film sensors and/or other microelectronic devices, followed by appropriate insulating layer(s), may be fabricated on or over the sacrificial substrate before forming the metal substrate. The sacrificial silicon substrate can then be etched away, leaving the microelectronics-grade metal substrate, and possibly the microelectronics device. Another insulating layer(s), followed by another adhesion layer, another seed layer and additional amounts of the material forming the metal substrate can then be deposited over the now-exposed microelectronics device to encapsulate it within a metal shell.