Improvement of Si₃N₄ etching kinetics and suppression of oxide regrowth phenomena are critical in the selective Si₃N₄ etching process on multi-layered Si₃N₄/SiO₂ structures for the fabrication of three-dimensional Not AND (3D NAND) devices. To control mass transfer of the solution and the Si₃N₄ etching by-product, various concentrations of H₃PO₄ solutions were used to remove Si₃N₄ layers of a patterned multi-layered Si₃N₄/SiO₂ structure. It was observed that oxide regrowth was suppressed by reducing the concentration of H₃PO₄, and 30 wt% H₃PO₄ produced the highest Si₃N₄/SiO₂ etching selectivity. In addition, amino acids with hydrophilic side chains, such as L-histidine, L-glutamic acid, L-proline, and L-lysine, were introduced into 30 wt% H₃PO₄. The introduction of amino acids increased the Si₃N₄ etching rate by providing hydrophilic side chains and polarizing silicon atoms on the Si₃N₄ surface. Furthermore, the addition of amino acids suppressed oxide regrowth by dehydration of the silanol group of the SiO₂-like Si₃N₄ etching by-product. Finally, Si₃N₄ could be selectively and uniformly etched in 30 wt% H₃PO₄ containing amino acids without oxide regrowth on multi-layered Si₃N₄/SiO₂ structures.

改善 Si ₃ N ₄蚀刻动力学和抑制氧化物再生长现象对于多层 Si 3 N 4 /SiO 2 结构的选择性 Si 3 N 4 蚀刻工艺_至关重要，_用于制造_三维Not AND ₍ 3D NAND)设备。为了控制溶液和Si ₃ N ₄蚀刻副产物的传质，使用不同浓度的H ₃ PO ₄溶液来去除图案化多层Si ₃ N ₄ /SiO _{2的Si 3} N _4层。结构。观察到通过降低H ₃ PO ₄的浓度来抑制氧化物再生长，并且30wt％的H ₃ PO ₄产生最高的Si ₃ N ₄ /SiO ₂蚀刻选择性。另外，将具有亲水性侧链的氨基酸，例如L-组氨酸、L-谷氨酸、L-脯氨酸和L-赖氨酸引入到30wt％的H 3 _PO 4_中。氨基酸的引入通过提供亲水性侧链和极化Si ₃ N _{4上的硅原子来提高Si 3} N _{4蚀刻速率}表面。此外，氨基酸的添加通过类SiO ₂ Si ₃ N ₄蚀刻副产物的硅烷醇基团的脱水抑制氧化物再生长。最后，Si ₃ N ₄可以在含有氨基酸的30wt％H ₃ PO ₄中选择性且均匀地蚀刻，而多层Si ₃ N ₄ /SiO ₂结构上没有氧化物再生长。