無電鍍鎳合金於薄膜電晶體顯示器閘極陣列之銅製程研究

Electroless Nickel-based Alloy Films Applied to Gate Electrode of TFT-LCD

許雯琪(Wen-Chi Hsu)

指導教授 ： 萬其超 ； 王詠雲

國立清華大學/工學院/化學工程學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00020

摘要

本論文以無電鍍法製備NiWMoB 做為覆蓋層。使用DMAB 當作還原劑及硼的來源，採用此種還原劑，不需先經鈀活化步驟可直接在銅面上還原。實驗中觀察到鍍率的關係為NiWB>NiWMoB>NiMoB。從鍍層鍍率以及鍍層組成的結果推測出W和Mo彼此為競爭關係。以掃描式電子顯微鏡觀察此三種鍍層，含有W的鍍層呈現含有較大晶粒的型態；而含有Mo的鍍層則是較小的晶粒存在。同時，再以X光粉末繞射儀觀察結晶型態，除了NiWB呈現明顯Ni的結晶，其餘的NiMoB或者是NiWMoB的結晶都比較偏奈米晶相，從半高寬值的關係推測晶粒的相對大小，此趨勢和掃描式電子顯微鏡的觀察符合。經由退火之後，觀察晶相的變化，NiWB會出現Ni3B的不穩定相，然而NiMoB或是NiWMoB則無其他不穩定相的產生。取[Na2WO4]/ [Na2MoO4] =1 ([Na2MoO4]:0.003M)製備NiWMoB，可以避免製備NiMoB會遇到鉬酸根吸附的問題，NiWMoB的熱穩定性也比NiWB良好，此條件下，晶粒尺寸小而且分布均勻。在此條件下，改變還原劑、錯合劑的濃度及氨水含量，藉以調整鍍層組成。討論這幾種不同組成中，硼含量對晶體結構以及防止銅的擴散的影響。從實驗結果，硼的含量越高的確可以防止銅的擴散。最後，以X光電子能譜儀分別觀察Ni、W、Mo及B在NiWMoB鍍層中以何種化學態存在。藉此我們發現Mo的化學態由於W的存在而受到影響，與其單獨存在時的化學態有所不同。

關鍵字

無電鍍 ； 薄膜電晶體顯示器 ； 閘極陣列 ； 銅製程

並列摘要

This study is to develop NiWMoB capping layer via electroless deposition. DMAB (dimethylamine borane) was chosen as the reducing agent due to its unique ability of selective deposition on copper surface without prior activation by Pd. In this study, various film compositions were fabricated, and their performance as capping layers were studied. The deposition rate reflects the relation: NiWB>NiWMoB>NiMoB. From the relation of deposition rate and the composition of the NiWMoB film, the introduction of both W and Mo leads to parallel competition in the reaction. The SEM photos reveal that deposits comprising W induces large grain size. On the other hand, the films consisting of amounts of Mo leads to small grain size. Based on the XRD patterns, the NiMoB or NiWMoB shows better thermal stability than NiWB films since no new phase appears after heat treatment with NiMoB or NiWMoB film. The NiWMoB films have superior thermal stability compared to NiWB films, and the addition of tungsten to NiMoB suppresses the adsorption of MoO42- on the catalytic surface, shortening the operating time. Under the condition of [Na2WO4]/ [Na2MoO4] =1 ([Na2MoO4]:0.003M), the morphology of the NiWMoB film presents uniform small grain and XRD data show nanocrystalline structure and sufficient thermal stability for NiWMoB deposits, rendering it a promising candidate as capping layer. The observation of Cu diffusion was evaluated by the depth profile. The results show that high-boron sample has no Cu diffusion, but low-boron sample has a little Cu diffusion. By utilizing XPS technique, the chemical states of Mo in the NiWMoB film were found affected by the addition of W.

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