電子迴旋共振化學氣相沉積之氧化矽膜及鎢在六氟化硫,氟化氮與氮氣的電漿蝕刻

Abstract

本論文包括兩部份:第一部份是電子迴旋共振沉積之氧化矽膜之研究;第二 部份鎢的六氟化硫,氟化氮與氮氣之電漿蝕刻.在第一部份中,我們研究了 壓力,流量比和溫度對沉積膜性質的影響.我們發現在某一特定的流量,較 高的溫度及較低的壓力下可得到較佳的氧化矽膜.在最佳的條件下,我們可 在高的沉積速率下製備出相當接近熱氧化成長的氧化矽膜.且在室溫下電 子迴旋共振沉積亦可製備出接近熱氧化成長的氧化矽膜.在第二部份我們 是用六氟化硫和氮氣及氟化氮及氮氣的電漿來蝕刻以硼磷玻璃為介電質的 鎢.我們發現其蝕刻速率對流量的變化和鎢蝕刻並不相同.它們和以氧化矽 為電漿電極的鎢蝕刻類似.這說明了當我們在半導體製程中欲進行鎢的蝕 刻時,必須也要把介電物質產生的效應考慮進去,因為它們之間在蝕刻時將 有相互作用會影響蝕刻的結果.此外,我們也發現用六氟化硫蝕刻後的鎢表 面外觀較氟化氮好. This thesis consists of two parts:ECR CVD oxide and tungsten etching by NF3/N2 and SF6/N2 plasmas. In the study of ECR CVD oxide, we investigate the influence of pressure, temperature, and the flow rate ratio on the quality of oxide film deposited by ECR CVD.We find that with a optimized flow rate ratio,lower pressure, and higher temperature we can prepare more stoichiometric films. Under the optimized process condition, we can prepare oxide films close to thermal oxide with high deposition rate. And near stoichiometric films can be deposited at room temperature by ECR CVD. The second part of this thesis is on the tungsten patterned BPSG samples etching by SF6/N2 and NF3/N2 plasmas. We find that the dependence of etching rate on etchant gas flow rate of tungsten patterned BPSG samples are different from that of pure tungsten sample.This suggests that we must take into account the effect resulting from the dielectric materials in etching tungsten in semiconductor process. Besides,from SEM photographs, we find that the surface morphology of tungsten etching by SF6/N2 is better than that of etching by NF3/N2.