Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1897
標題: 晶圓銅膜無磨粒化學機械拋光機制研究
A STUDY ON WEAR MECHANISMS FOR ABRASIVE FREE POLISHING OF WAFERS WITH COPPER FILM
作者: 林永成
Lin, Yong-Cheng
關鍵字: Abrasive free polishing (AFP);無磨粒化學機械拋光;benzotriazole (BTA);citric acid (CA);shear stress;苯基疊氮;檸檬酸;剪應力
出版社: 機械工程學系
摘要: 
無磨粒化學機械拋光(AFP)為不添加研磨粒的平坦化技術,可避免化學機械拋光所造成的晶圓表面刮痕缺陷,故為半導體銅製程晶圓拋光平坦化的主要技術。本研究探討AFP的材料拋光移除機制,AFP的材料移除分為三階段,分別為非接觸區的化學腐蝕、鈍化層生成以及接觸區的機械剔除,由三階段的各別移除方式找出估算拋光移除率的關係式,並設計實驗相互比對,確認其適用性。本研究結果歸納為(1)當壓力增加時,拋光墊與晶圓接觸面積增加,機械移除的重要性相對提昇;當轉速增加時,二者接觸面積減少,將使得化學反應重要性提高;(2)隨著壓力與轉速的增加,晶圓表面所受到的總剪應力隨之增加,材料移除率會提升;(3)實驗結果顯示化學漿料有助於提升材料移除率且添加檸檬酸(CA)之移除率均較添加苯基疊氮(BTA)之移除率高;(4)計算求得的鈍化層移除率,顯示添加BTA所生成的鈍化層比添加CA所生成的鈍化層來得厚,使得添加BTA的漿料系統拋光前後的銅膜厚度變化量較小,此與實驗一致,顯示本研究所提出的移除機制適用。

Abrasive free polishing (AFP) is the technology for planarization and polishing of wafers without abrasives. As it can avoid surface scratch of wafer in the polishing process, AFP has become the main technology in the planarization of wafer with copper film in semiconductor fabrication. This research investigates material removal mechanisms of AFP that includes chemical corrosion, passivation in non-contact region and mechanical wear in contact region. The removal rate can be estimated based on these three mechanisms. In addition, experiments are designed and conducted as a comparison with the theoretical calculation. The results of this research lead to the following conclusions. (1) The role of mechanical wear is more important as the contact area between the wafer and pad increases at higher polishing pressure. Chemical reaction becomes more crucial as the polishing speed increases, causing the decrease of contact area between the wafer and pad. (2) The shear stress on wafer and removal rate (RR) increase with the pressure and speed. (3) Experimental results showed that polishing slurry with chemical solution assists the removal of material. RR of slurry with Citric Acid (CA) as an additive is higher than that with benzotriazole (BTA) added. (4) The thickness of passivative film, based on the calculation from RR, with BTA as an additive is higher than that with CA as an additive. It further implies that the variation of removed copper film with BTA as an additive is less than that of polishing solution with CA. Such good consistency between the theory and experimental results indicates the models of material removal in this research can provide a good estimation.
URI: http://hdl.handle.net/11455/1897
Appears in Collections:機械工程學系所

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