DEVELOPMENT OF ANISOTROPIC ETCHING TECHNOLOGY WITH PERFECT SELECTIVITY USING LANGMUIR'S ADSORPTION LAYER

利用 Langmuir 吸附层开发具有完美选择性的各向异性蚀刻技术

• 批准号: 03555057
• 负责人: MATSUURA Takashi
• 金额: $ 4.93万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03555057/
• 关键词: ECR Plasma; Langmuir's Adsorption; Etching Delay Time; Perfect Selectivity; Anisotropy; Selective Epitaxy; Ultraclean; Nitrogen Addition

The object of this research is to develop an anisotropic etching technology with perfect selectivity using Langmuir's adsorption layer, with focusing on selective plasma processing. Research results are summarized as follows.(1) In ECR plasma etching, under an ultraclean condition with eliminating deoxidizing contamination onto the wafer and suppressing damages caused by ion incidence, nitrogen to addition to chlorine drastically enhances anisotropy. Direct ESCA analysis of the side wall surface of n^+-polysilicon reveals chemisorption of the N-atom forming Si-N bonds, which results in anisotropy enhancement. Exposure of the N-chemisorbed n^+-polysilicon surface to clean room air results in oxidation of the surface.(2) The added nitrogen dependence of the etch rate is well characterized by a Langmuir-type adsorption and reaction scheme as a competitive reaction with nitrogen and chlorine. Furthermore, using the horizontal over-etch rates with and without nitrogen addition, transport and deactivation of chlorine and nitrogen radicals are evaluated.(3) Using the same ultraclean ECR plasma system, low temperature Si selective epitaxy and inversion to selective polysilicon deposition only on SiO_2 without substrate heating was achieved by SiH_4 decomposition with a H_2 added Ar plasma. ESCA analysis shows the Si^0 adsorption on the masking SiO_2 surface, which originates from SiH_4 and suppresses SiO_2 etching, in Si selective epitaxy. Moreover, the inversion in selectivity results from the competitive contributions of chemical etching with hydrogen radicals and ion induced decomposition of SiH_4.

本研究的目的是发展一种各向异性蚀刻技术与完美的选择性使用朗缪尔的吸附层，重点是选择性等离子体处理。研究结果总结如下。(1)在ECR等离子体蚀刻中，在消除晶片上的脱氧污染并抑制由离子入射引起的损伤的超净条件下，向氯中添加氮显著增强各向异性。对n^+-多晶硅侧壁表面的直接ESCA分析表明，N原子的化学吸附形成Si-N键，导致各向异性增强。将N-化学吸附的n^+-多晶硅表面暴露于洁净室空气中会导致表面氧化。(2)添加的氮的蚀刻速率的依赖性是很好的特征在于一个朗缪尔型吸附和反应方案作为一个竞争性的反应与氮和氯。此外，使用水平过蚀刻速率与和没有氮添加，运输和失活的氯和氮自由基进行评估。(3)采用相同的超净ECR等离子体系统，在不加热衬底的情况下，通过SiH_4分解和H_2加Ar等离子体，实现了SiO_2上的低温Si选择性外延和选择性多晶硅的反转沉积。ESCA分析表明，在Si选择性外延过程中，Si^0吸附在掩蔽SiO_2表面，其来源于SiH_4，抑制了SiO_2的刻蚀。此外，选择性的反转是由氢自由基化学腐蚀和SiH_4离子诱导分解的竞争贡献引起的。

项目成果

K.FUKUDA et al.: "Low-Temperature Silicon Epitaxy without Substrate Heating by Ultraclean ECR-Plasma-Enhanced CVD" Extended Abstract 179t Electrochemical Society Spring Meeting.Washington DC. 91-1. 575-576 (1991)

K.FUKUDA 等人：“通过超洁净 ECR 等离子体增强 CVD 实现无需基板加热的低温硅外延”扩展摘要 179t 电化学学会春季会议。华盛顿特区。

T.Matsuura et al.: "Effects of Gas Addition in Ultraclean Electron Cyclotron Resonance Plasma Etching of Polysilicon"

T.Matsuura 等人：“多晶硅超净电子回旋共振等离子体蚀刻中气体添加的影响”

T.Matsuura et al.: "Anisotropy improvement by nitrogen chemisorption in highly selective etching of n^+-polysilicon using an ultraclean electron-cyclotron-resonance N_2/Cl_2 plasma"

T.Matsuura 等人：“使用超净电子回旋共振 N_2/Cl_2 等离子体对 n^-多晶硅进行高选择性蚀刻，通过氮化学吸附改善各向异性”

T. Matsuura, H. Uetake, T. Ohmi, J. Murota, and S. Ono.: "Anisotropic etching process of n^+-polysilicon with chlorine and nitrogen mixed ECR plasma" Extended Abstracts 179th Electrochemical Society. May. 521-522 (1991)

T. Matsuura、H. Uetake、T. Ohmi、J. Murota 和 S. Ono.：“使用氯和氮混合 ECR 等离子体对 n^ -多晶硅进行各向异性蚀刻工艺”扩展摘要第 179 届电化学会。

K.Fukuda et al.: "Electron-cyclotron-resonance plasma-enhanced chemical-vapor-deposition of epitaxial Si without substrate heating by ultraclean processing." Applied Physics Letters. 59. 2853-2855 (1991)

K.Fukuda 等人：“电子回旋共振等离子体增强外延硅化学气相沉积，无需通过超净处理加热基板。”