Microelectronics and, in particular, superconducting quantum processors increasingly depend upon 3D metal structures to overcome constraints of purely planar, 2D microfabrication on low-loss dielectric surfaces (such as sapphire or silicon). Within superconducting qubit devices, the most common example are airbridges that allow for electrical pathways to be routed up and over other electrical pathways. In the superconducting qubit space, these airbridges are commonly made from high purity aluminum or titanium.  
To microfabricate these 3D structures, it is common to use one or more layers of polymer photoresist, which can be readily patterned into an arbitrary shape. That shape is then transferred to the metal by depositing a layer of metal on top of the resist and then removing the resist by chemical treatment. The drawback of this technique is contamination – the product always includes some carbon-containing residue which can be detrimental to performance.  The most aggressive common treatment to remove such residues is a 'Piranha etch' solution (a mixture of sulfuric acid and hydrogen peroxide), and as the name implies, it can dissolve many things including most metals, such as aluminum and titanium. 
Tantalum has excellent electronic and mechanical properties and can withstand such strong corrosive mixtures. Moreover, its relatively high superconducting temperature (4.3 K) and superior surface qualities make it suitable for low-loss superconducting channels, such as those in superconducting qubit processors. But making films with high conductivity (the bcc phase of the crystal) typically requires temperatures more than 500 °C, which will deteriorate any polymer resist structure.