大尺寸高端显示器件用薄膜晶体管Al–Mo复合电极坡度的形成过程与可控调节  

Formation process and adjustment of the profile angle of Al–Mocomposite electrodes in thin-film transistors for large-size premiumdisplays

作　　者：刘丹 欧忠文 方亮[1,5] 黄中浩 李砚秋 熊永 林鸿涛 欧影轻 刘璐 Dan Liu;Zhongwen Ou;Liang Fang;Zhonghao Huang;Yanqiu Li;Yong Xiong;Hongtao Lin;Yingqing Ou;Lu Liu(Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Material,College of Physics,Chongqing University,Chongqing 400044,China;The Army Logistic University of PLA,Chongqing 401331,China;Chongqing BOE Optoelectronics Technology Co.,Ltd.,Chongqing 400700,China;Beijing BOE Display Technology Co.,Ltd.,Beijing 100176,China;Institute for Smart City of Chongqing University,Liyang 213300,China)

机构地区：[1]软凝聚态物理及智能材料研究重庆市重点实验室,重庆大学物理学院,重庆400044 [2]中国人民解放军陆军勤务学院,重庆401331 [3]重庆京东方光电科技有限公司,重庆400700 [4]北京京东方显示技术有限公司,北京100176 [5]重庆大学溧阳智慧城市研究院,江苏213300

出　　处：《中国科学：化学》2023年第10期2079-2088,共10页SCIENTIA SINICA Chimica

基　　金：四川省科技攻关项目(2022YFSY0042,2022YFQ0019);中央高校项目基础研究基金项目(2022CDJQY-007);重庆京东方光电科技有限公司科技项目(No.12927);腐蚀与防护四川省重点实验室开放课题(2022CL25);重庆大学大型仪器开放基金课题(202303150164,202303150169,202303150178)资助项目。

摘　　要：栅极坡度角(PA)对薄膜晶体管(TFT)性能和良率具有重要影响,如何将坡度角调节到合适的范围是TFT量产中关键技术之一.本文以大尺寸高端显示器件用a-Si TFT的Al/Mo、Mo/Al/Mo电极在磷酸系溶液下刻蚀得到的坡度角为研究对象,探究了膜层结构、Mo厚度、刻蚀时间对坡度角的影响.结果表明:在Al/Mo结构中,随着顶Mo厚度增加,Al与光刻胶之间的间隙增加,刻蚀液更易侵入,侧向刻蚀增强,坡度角减小;在Mo/Al/Mo三层电极结构中,随着底Mo厚度增加,底Mo和中间临近的Al侧壁发生电偶腐蚀,Al侧壁上形成氧化物钝化层,Al刻蚀速率减慢,坡度角变小.水池效应将导致刻蚀液残留在电极底部,阻碍新鲜刻蚀液与底部接触,底部刻蚀速率低于顶部;故当刻蚀时间延长时,底部和顶部刻蚀速率差进一步增大,导致坡度角减小.得到了Mo/Al/Mo坡度角与顶Mo和底Mo厚度回归方程,为调节坡度角和优选Mo厚度提供了依据.此电极坡度角的调节技术可为确保TFT的良率和性能提供参考.The profile angle(PA)of gate electrodes has a significant impact on thin film transistor(TFT)performance and yield.The influence of film structure,Mo thickness,and etching time on the PAs of Al/Mo and Mo/Al/Mo electrodes of a-Si TFT etched in phosphoric-based acid solution was investigated.The results showed that in the Al/Mo dual-layer structure,the PAs decrease with the increase of the thickness of the top Mo layer,owing to the enhanced lateral etching caused by the easier invasion of the etching solution as the gap between Al and photoresist(PR)increases.In the Mo/Al/Mo three-layer electrode structure,as the thickness of the bottom Mo increases,the galvanic corrosion occurs between the bottom Mo and the adjacent middle Al sidewalls.An oxide passivation layer is formed on the Al sidewalls,which slows down the etching of Al and reduces the PAs.Due to the pool effect,the residual etchant at the bottom of the electrode hinders the contact between the fresh etchant and the bottom metal,resulting in a lower etching rate at the bottom than that at the top;thus as the etching time is extended,the difference in the etching rate between the bottom and top further increases,leading to a decrease of PAs.The regression equation between PA and the thickness of top and bottom Mo layers was obtained,providing a basis for adjusting PAs and optimizing Mo thickness.The proposed adjustment technology of electrode PAs may provide a reference for ensuring the yield and performance of TFTs.

关 键 词：薄膜晶体管 AL电极 坡度角 叠层结构 水池效应 电偶腐蚀 

分 类 号：TN321.5[电子电信—物理电子学]