  We present a novel ion trap fabrication method enabling the realization of
multilayer ion traps scalable to an in principle arbitrary number of
metal-dielectric levels. We benchmark our method by fabricating a multilayer
ion trap with integrated three-dimensional microwave circuitry. We demonstrate
ion trapping and microwave control of the hyperfine states of a laser cooled
$\,^{9}$Be$^{+}$ ion held at a distance of 35$\,\mu$m above the trap surface.
This method can be used to implement large-scale ion trap arrays for scalable
quantum information processing and quantum simulation.
