  Neutral atoms can be trapped and manipulated with surface mounted microscopic
current carrying and charged structures. We present a lithographic fabrication
process for such atom chips based on evaporated metal films. The size limit of
this process is below 1$\mu$m. At room temperature, thin wires can carry more
than 10$^7$A/cm$^2$ current density and voltages of more than 500V. Extensive
test measurements for different substrates and metal thicknesses (up to 5
$\mu$m) are compared to models for the heating characteristics of the
microscopic wires. Among the materials tested, we find that Si is the best
suited substrate for atom chips.
