探討化學氣相沉積在先進動態隨機存取記憶體淺溝槽絕緣的填洞能力

Abstract

在於本碩士論文裡, 我們旨在利用 HARP-SACVD 以化學氣相沉積方式來探討如何以沒有摻質的玻璃來延伸先進動態隨機存取記憶體淺溝絕緣的填動能力。根據這次實驗結果，三步驟的沉積方式可以滿足，並沒有發現縫道在 60 奈米的槽寬度以及 AR 7:1 槽溝之填洞結果。第一步沉積是利用較高的 Ozone /TEOS 比例來得到極佳的階梯覆蓋，減少表面的選擇性，第二步沉積旨在不改變 Ozone/TEOS 之比例下，利用較少 TEOS 的流量來完成淺溝槽之填洞。而最後的沉積目的是增加晶片之生產量。 在本實驗中亦探討 TEOS 的初期流量以及完成 HARP 之玻璃沉積後回火處裡方式對淺溝槽填洞能力之影響。

In this thesis, we explored the extendibility of shallow trench isolation (STI) gap filling capability of undoped silicate glass (USG) prepared by high aspect ratio process (HARP) in sub-atmosphere chemical vapor deposition (SACVD) systems for sub-70 nm technology nodes for the advanced dynamic random access memory (DRAM) applications. Based on the study, a 3-step deposition process, which is capable of achieving void free gap filling at 0.06μm trench width and > 7:1 aspect ratio with a smooth profile of trench sidewall, was developed. The first step is to deposit a homogeneous nucleation layer with trivial surface selectivity by using a gas source with a high O3/ tetraethoxysilane (TEOS) ratio so that better film conformality can be achieved. The second step is to deposit a sufficiently thick USG to fill trenches with a small to moderate width by using a gas feed of a relatively high O3/TEOS ratio. The final step is targeted at throughput enhancement. The effect of initial TEOS composition and annealing treatment after the HARP USG deposition on the trench filling capability was also studied.