先進栓塞材料開發與製程整合
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2014
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摘要
在90年代末期，內連結導線部分應用逐漸被銅取代，但是垂直連結的栓塞材料仍就是鎢，主要考量鎢的熱與化學穩定性佳。但在逐漸微縮的元件要求下，傳統以CVD方式沉積的栓塞因阻值增高，衍生的寄生電阻串聯效應，將會嚴重影響元件特性。
在本研究中，我們比較以不同方式(PVD& ALD)製備TiN當作擴散阻絕層(Diffusion Barryier Layer)，鎢(W)當垂直栓塞導線。TiN是傳統鎢栓塞使用的擴散阻障層材料。而ALD製程是目前製作極薄、均勻薄膜的理想製程。本研究結合電漿結構改質與雜質摻雜的方式，試圖改變ALD-TiN在製程後的結構，以提高其高溫阻絕擴散能力，並透過Ag/n+ p-Si結構的二極體來觀察高溫漏電流行為，評斷阻絕能力。
整合方面，本實驗以 200nm x 200nm 的Contact Plug Size為主，水平導線採用(Al-Si-Cu)，製作接觸鏈(Contact chain)結構，探討不同製程下的垂直栓塞材料(W)之電性，並建立一套栓塞電阻量測結構製程流程(Process Flow)。藉由實驗的結果，探討如何降低整體鎢栓塞電阻值的方法，以及選用不同方式的擴散阻絕層製程以及改善方式，一方面減少填充時的孔洞，另一方面提升擴散阻絕能力，提供給下一世代栓塞製程延伸的選擇。 關鍵字：栓塞、鎢、擴散阻障
Abstract In 1990s, Cu has lower electrical resistance and EM resist performances than Al became the new interconnect metal. Cu was also regarded as the candidate of contact material in replace of tungsten. However, high diffusivity of Cu through thinner diffusion barrier will be the major concern. In plug process improvement, we modified the standard recipe of CVD W process combined with the ALD-TiN material to enlarge the process window. Not only the void-free gap fill was achieved in 100nm plug structure but the plug resistance was effectively reduced with following forming gas annealing. In this study, we optimized TiN microstructure and N/Ti composition ratio using N plasma bombardment to enhance the diffusion retardation capability. An Ag/n+p-Si diode was fabricated to detect the leakage current/barrier performance of modified TiN film. A contact chain with 200m x 200m plug size was produced for plug resistance study. Different plug barrier material and modified CVD W process were fabricated for comparison. An integration process flow and capability for contact plug study was expected to be built-up in this study. Key word: Plug、Material Development、Contact chain
Abstract In 1990s, Cu has lower electrical resistance and EM resist performances than Al became the new interconnect metal. Cu was also regarded as the candidate of contact material in replace of tungsten. However, high diffusivity of Cu through thinner diffusion barrier will be the major concern. In plug process improvement, we modified the standard recipe of CVD W process combined with the ALD-TiN material to enlarge the process window. Not only the void-free gap fill was achieved in 100nm plug structure but the plug resistance was effectively reduced with following forming gas annealing. In this study, we optimized TiN microstructure and N/Ti composition ratio using N plasma bombardment to enhance the diffusion retardation capability. An Ag/n+p-Si diode was fabricated to detect the leakage current/barrier performance of modified TiN film. A contact chain with 200m x 200m plug size was produced for plug resistance study. Different plug barrier material and modified CVD W process were fabricated for comparison. An integration process flow and capability for contact plug study was expected to be built-up in this study. Key word: Plug、Material Development、Contact chain
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Keywords
栓塞, 鎢, 擴散阻障, Plug, Material Development, Contact chain