EXIM is a PVD (physical vapor deposition) system developed to form thin-film materials required for advanced semiconductor devices. It is based on ultra-high-vacuum sputtering technology and incorporates newly-developed film deposition techniques to form complex stacks of precision electronic materials. This flexible system can accommodate a variety of process modules to meet specific application needs, and the system can scale flexibly to suit various purposes, ranging from development to volume production.
Early evaluators of EXIM have explored its unique capabilities to form multi-layer magnetic tunnel junction (MTJ) stacks for spin-transfer-torque magnetoresistive random access memories (STT-MRAM). When used to form MTJ stacks with 20 or more layers, EXIM delivered a throughput on the order of 25 wafers per hour*1. Stacks have been demonstrated with good magnetic memory characteristics, and a TMR (Tunneling magnetoresistance) ratio*2 over 230% with TEL’s unique perpendicular MTJ stack*3.
TEL’s initial orders for the EXIM system have been for STT-MRAM applications, an emerging technology that shows potential for enabling a new generation of high-performance, low-power devices. The company will build on EXIM’s superior scalability and productivity to further expand its applications to other device sectors.
*1The throughput may vary depending on the structure of MTJs.
*2TMR ratio is the ratio of the resistance change that occurs when the magnetization directions between free and reference layer switch from parallel state to anti-parallel state, and vice versa.
Higher MR ratio is essential for manufacturing of large capacity memory devices.
*3Magnetization direction of the MTJs are perpendicular to the plane due to the large magnetic anisotropy, and hence the recording density is enhanced.