Using an HDP reactor to make barrier stack etches for MEMS devices

Corrosion resistance, electromigration resistance, and compatibility with standard IC fabs make platinum attractive as an interconnect in MEMS applications. Platinum and lead zirconate titanate etch rates greater than 1000Angstrom/min are possible at moderate (80AngstromC) wafer temperatures using photoresist maskss in a high-density plasma etch system. Etch profiles with no post-etch residue for metal-ferroelectric-metal stacks like those used for a MEMS-based atomic force microscopy applications, for example, which employs a bottom platinum layer = 1500Angstrom, 2800Angstrom of lead zirconate titanate, and a platinum top electrode = 1500Angstrom, can be achieved. Production data from a process for etching a platinum/titanium-tungsten stack for a micromachined miror device are also presented.