Optimization of Tilted Profile in Ultra-High Aspect Ratio Etch Process for 3D NAND Flash Memory
Jinqing He, Zhiliang Xia, Meng Wang, Guangxuan Zhang, Haiqing Dou, Zongliang Huo
Abstract
In 3D NAND flash memory fabrication, tilting issue has been exacerbated as aspect ratio of features increase to beyond 50, which constrains improvement of memory density. The distortion can be mainly attributed to tilted ion trajectory, which is caused by sheath thickness variation. This paper reports advanced methods of optimizing sheath thickness uniformity. As a result, ultra-high aspect ratio trench structures, with straight sidewall profile across a whole 12-inch wafer, have been realized successfully.
Topics & Concepts
Materials scienceWaferAspect ratio (aeronautics)Flash (photography)TrenchNAND gateFabricationEtching (microfabrication)Flash memoryOptoelectronicsDistortion (music)Shallow trench isolationProcess (computing)Computer scienceElectronic engineeringLogic gateOpticsNanotechnologyComputer hardwareEngineeringPhysicsAlternative medicineOperating systemMedicineLayer (electronics)PathologyAmplifierCMOSPlasma Diagnostics and ApplicationsSemiconductor materials and devicesAdvanced Surface Polishing Techniques