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We present the first Embedded Spin-Transfer-Torque MRAM (eMRAM) technology in a 14 nm CMOS node. A novel integration supports the highest eMRAM density (0.0273 um2 cell size), optimal magnetic tunnel junction (MTJ) placement between M1-M2 for performance and density, and the lowest-cost integration scheme, with only 3 added mask levels (2 critical + 1 non-critical) and a single added electrode module. An advanced 400°C-compatible MTJ stack is read and written by innovative reference-cell sensing circuitry. We demonstrate digital functionality and write performance down to 4 ns, with companion parametric analysis for magnetoresistance, switching voltage, retention, and endurance cycling. Finally, we checked the 14 nm eMRAM hardware BEOL EM and TDDB at the critical levels, verifying good reliability after the embedding process.

This paper presents a multi-step process to improve the stability of plasma ignition of a magnetic target in a multi-cathode physical vapor deposition (PVD) system. Most target materials in the system have no issues igniting a stable plasma. The material in question is a material for which it is much more difficult to ignite a reliable plasma because it is a more complex target made of different compounds, therefore this target will be affected by grain size, impurities, and other factors from its manufacturing, therefore there are more ignition faults and retries than with other conventional targets using the same recipe settings. It was found that ignition retries and faults can be improved by implementing sequence start cleans, high pressure ignition using the sputter on shield, and/or by using a higher wattage power supply to ignite the plasma with the ion gauge on. Each method was shown to decrease the number of retries and faults and can be used on PVD systems with targets which are difficult to ignite. Any combination of these solutions should result in improvement of up to 50% reduction in ignition faults.