Process Data

Memory Device: MTJ Etching

Overview

MTJ etching is a critical process for MRAM fabrication. The MTJ consists of an complex series of nanoscale metal films and oxide dielectric layers. Applying the techniques of traditional reactive ion etching process will result in non-volatile byproducts. Such non-volatile byproducts will re-deposit on the MTJ sidewalls, making the device non-functional, and affecting device stability. Besides, if the MTJ is exposed in the ambient environment after etching, it will react with the water vapor in the surroundings, resulting in device degradation.

The LMEC-300™ system integrates multiple modules, including RIE, IBE and CVD in-situ encapsulation chambers. The LMEC-300™ system effectively removes non-volatile etching residue, and prevents plasma-induced damage. The in-situ encapsulation module ensures that the MTJ is coated with a protective layer after etching without vacuum break, which helps avoid device degradation.

Similarly, the LMEC-300™ system works equally well for the etch and in-situ passivation of phase change alloys in PCRAMs, resistive metal-oxide-metal stacks containing special metals in ReRAMs, and Josephson junctions in spin qubit chips for quantum computing.