後續處理對低介電常數材料HSQ的特性探討

Abstract

本論文主要研究具有低介電值材料旋轉式塗佈介電材質HSQ質來降低金 屬連線中的電容.為 了達到最佳化的HSQ,HSQ表面上必須有足夠的Si-H bonds保護，因為HSQ為多孔性所以容易吸收水氣，但Si-H bonds容易因過 熱而被打斷，所以我們使用氫氣電漿處理以使原本斷掉的Si-H bonds重新 形成鍵結。當我們使用氫氣電漿處理時,發現HSQ的漏電流變小，而隨著氫 氣電漿處理的時間增長，而漏電流變的越來越小。此外,我們也研究了氧 氣電漿和氮氣電漿對HSQ的影響.其中,我們發現, 氧氣電漿處理會得最差 的結果,氮氣電漿處理最穩定. 最後,我們還使用了氟的離子佈值,結果發 現,氟的離子佈值可以增加HSQ的熱穩定性 . Low density material such as hydrogen silsesquioxane (HSQ) can offer lowerdielectric constant .With HSQ ,a low value of K can be achieved if the densityof Si-H bonds is maintained at a high level and the formation of -OH bonds andabsorption or creation of water in the film is minimized . In this work , westudy the hydrogen plasma to improve the quality of HSQ . The leakage current ofHSQ decreases with increasing the H2 plasma treatment time . A model is proposedto explain the role of hydrogen in the HSQ .The role of hydrogen to the lowdielectric HSQ is to passivate the surface of porous HSQ . If the surface is notpassivated by hydrogen , much of those dangling bonds will remain on the surface.Dangling bonds can easily absorb moisture and form -OH bonds which will resultin increasing the dielectric constant . In addition , the dangling bonds willincrease leakage current . H2 plasma treatment provides hydrogen to passivatethe surface and to reduce the dangling bonds to achieve good property of HSQ .The Si-H bond density can be reduce by O2 plasma as well as by inappropriatefurnace processing. In addition ,the HSQ is treated by fluorine implanted ,the good thermal stability of HSQ can be achieved .