NH₄OH용액이 반도체 소자용 구리 박막 표면에 미치는 영향 (Cleaning Effects by NH₄OH Solution on Surface of Cu Film for Semiconductor Devices)

서지정보

· 발행기관 : 한국재료학회
· 수록지 정보 : 한국재료학회지 / 22권 / 9호 / 459 ~ 464페이지
· 저자명 : 이연승, 나사균, 노상수

초록

We investigated cleaning effects using NH4OH solution on the surface of Cu film. A 20 nm Cu film was deposited on Ti / p-Si (100) by sputter deposition and was exposed to air for growth of the native Cu oxide. In order to remove the Cu native oxide, an NH4OH cleaning process with and without TS-40A pre-treatment was carried out. After the NH4OH cleaning without TS-40A pretreatment, the sheet resistance Rs of the Cu film and the surface morphology changed slightly(ΔRs:~10 mΩ/sq.). On the other hand, after NH4OH cleaning with TS-40A pretreatment, the Rs of the Cu film changed abruptly (ΔRs: till ~700 mΩ/sq.); in addition, cracks showed on the surface of the Cu film. According to XPS results, Si ingredient was detected on the surface of all Cu films pretreated with TS-40A. This Si ingredient(a kind of silicate) may result from the TS-40A solution, because sodium metasilicate is included in TS-40A as an alkaline degreasing agent. Finally, we found that the NH4OH cleaning process without pretreatment using an alkaline cleanser containing a silicate ingredient is more useful at removing Cu oxides on Cu film. In addition, we found that in the NH4OH cleaning process, an alkaline cleanser like Metex TS-40A, containing sodium metasilicate, can cause cracks on the surface of Cu film.

영어초록

We investigated cleaning effects using NH4OH solution on the surface of Cu film. A 20 nm Cu film was deposited on Ti / p-Si (100) by sputter deposition and was exposed to air for growth of the native Cu oxide. In order to remove the Cu native oxide, an NH4OH cleaning process with and without TS-40A pre-treatment was carried out. After the NH4OH cleaning without TS-40A pretreatment, the sheet resistance Rs of the Cu film and the surface morphology changed slightly(ΔRs:~10 mΩ/sq.). On the other hand, after NH4OH cleaning with TS-40A pretreatment, the Rs of the Cu film changed abruptly (ΔRs: till ~700 mΩ/sq.); in addition, cracks showed on the surface of the Cu film. According to XPS results, Si ingredient was detected on the surface of all Cu films pretreated with TS-40A. This Si ingredient(a kind of silicate) may result from the TS-40A solution, because sodium metasilicate is included in TS-40A as an alkaline degreasing agent. Finally, we found that the NH4OH cleaning process without pretreatment using an alkaline cleanser containing a silicate ingredient is more useful at removing Cu oxides on Cu film. In addition, we found that in the NH4OH cleaning process, an alkaline cleanser like Metex TS-40A, containing sodium metasilicate, can cause cracks on the surface of Cu film.

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