Xilin Peng

An approach for nanometer trench and hole formation

Patterning trench-hole type of structures with CD in nanometer dimension is very challenging in optical lithography due to limited depth of focus (DOF) and exposure latitude (EL). We have proposed an integration process to convert sub- 100nm line/post type of structure to trench/hole type of structure. The proposed method as well as its variations may have various potential applications, such as formation of plated perpendicular magnetic writer pole, bottom-up nanointerconnect, nano-wires and other out-of-plane nano-structures. We have shown the feasibility for formation of nanotrenches in various sub-100nm dimensions. Magnetic writer pole with 50nm critical dimensions (CD) and wellcontrolled sidewalls was demonstrated by using this approach. The minimum CD of the starting isolated line/post feature determines the minimum CD of the trench/hole structure.

Study of SiOxNy as a bottom antireflective coating and its pattern transferring capability

To meet such challenges for the controlling of critical feature dimension at sub-50–100‐nm, it has been a general industrial trend to employ shorter wavelength (193nm, for example) lithography for better resolution and to use bottom antireflective coating (BARC) for a reduced standing wave formation and thus, a better critical dimensional control. Matching the optical constants (n,k) between the BARC, photoresist, and the underlayer to be patterned is critical for the elimination of such standing waves. SiOxNy and SiOxCy are two attractive inorganic BARC candidates in view of their easily adjustable optical constants by varying the deposition parameters and their etching compatibility with standard semiconductor plasma processes. In this article, SiOxNy films were prepared by plasma enhanced chemical vapor deposition approach. These films have been further characterized using x-ray photoelectron spectroscopy for chemical composition depth profile, Fourier transform infrared spectroscopy for local chemical...

Interface stability between amorphous ferromagnetic layer and Al oxide barrier in tunneling magnetoresistive films at elevated temperatures

The interface stability and microstructure between amorphous and crystalline ferromagnetic (FM) layers Fe56Co24B20 and Co70Fe30 (at. %) and oxide barrier layers (AlO) deposited by physical vapor deposition, in both as-deposited and annealed states, have been studied using hysteresis loops for magnetic measurement, x-ray photoelectron spectroscopy for elemental depth profiling, and transmission electron microscopy for atomic-level microstructure. AlO was found to be amorphous on both amorphous Fe56Co24B20 and polycrystalline Fe30Co70 FM layers. Substantial Fe diffusion towards the AlO layer and Al diffusion towards the FM layer are clearly observed for the Fe56Co24B20∕AlO system when annealed above 360°C and will likely cause magnetic tunneling junction devices made from this system to fail.