마이크로전자및패키징학회지 (Journal of the Microelectronics and Packaging Society)

  • 제25권4호
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  • Pages.123-128
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  • 2018
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  • 1226-9360(pISSN)
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  • 2287-7525(eISSN)
한국마이크로전자및패키징학회 (The Korean Microelectronics and Packaging Society)
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플럭스 활성제 종류에 따른 Sn-Ag-Cu 솔더 페이스트의 젖음성 및 슬럼프 특성 평가

Effects of Flux Activator on Wettability and Slump of Sn-Ag-Cu Solder Paste

  • 권순용 (한국생산기술연구원 용접접합그룹 마이크로조이닝센터) ;
  • 서원일 (한국생산기술연구원 용접접합그룹 마이크로조이닝센터) ;
  • 고용호 (한국생산기술연구원 용접접합그룹 마이크로조이닝센터) ;
  • 이후정 (성균관대학교 신소재공학부) ;
  • 유세훈 (한국생산기술연구원 용접접합그룹 마이크로조이닝센터)
  • Kwon, Soonyong (Joining R&D Group, Korea Institute of Industrial Technology) ;
  • Seo, Wonil (Joining R&D Group, Korea Institute of Industrial Technology) ;
  • Ko, Yong-Ho (Joining R&D Group, Korea Institute of Industrial Technology) ;
  • Lee, Hoo-Jeong (School of Advanced Material Science and Engineering, Sungkyunkwan University) ;
  • Yoo, Sehoon (Joining R&D Group, Korea Institute of Industrial Technology)
  • 투고 : 2018.12.21
  • 심사 : 2018.12.28
  • 발행 : 2018.12.31
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초록

플럭스의 활성제 종류에 따른 솔더페이스트의 인쇄성 및 젖음성을 평가하였다. 활성제는 디카르복실산 계열로 탄소기의 개수가 0인 옥살산, 1인 말론산, 2인 숙신산, 3인 글루타르산, 4인 아디프산, 5인 피메릭산이 사용되었다. SMT scope로 $250^{\circ}C$에서 용융솔더를 실시간 관찰했을 때, 글루타르산을 사용한 솔더가 가장 매끈한 표면을 갖고, 젖음성도 우수함을 알 수 있었다. 슬럼프율은 탄소기 개수가 1, 2, 3인 말론산, 숙신산, 글루타르산을 활성제로 사용했을 때 작았고, 퍼짐성은 활성제의 탄소기 개수가 2 이상인 숙신산, 글루타르산, 아디프산, 피메릭산을 사용했을 때 우수하였다. 웨팅밸런스로 젖음성을 분석한 결과 탄소기 개수가 3이상일 때, 제로크로스타임이 1초 이하로 우수함을 알 수 있었다. 탄소기 개수가 0, 1인 옥살산, 말론산을 플럭스 활성제로 사용하였을 때, 제로크로스 타임이 길고 최대 젖음력이 낮았다. DSC와 TGA를 통해 옥살산과 말론산을 활성제로 사용한 플럭스는 솔더링 시 분해가 발생되고, 이로 인해 활성도가 떨어져서 디웨팅 등이 발생하였다. 글루타르산은 재산화가 적고, 높은 젖음성과 낮은 슬럼프 특성을 보여 주었다.

Effect of activators in flux on the printability and wettability of a solder paste was evaluated in this study. The activators in this study were dicarboxylic acids, which were oxalic acid (n = 0), malonic acid (n = 1), succinic acid (n = 2), glutaric acid (n = 3), adipic acid (n = 4), and pimelic acid (n = 5). When the solder pastes were observed with a SMT scope, solder with glutaric acid showed clean and shiny surface when it was melted. Slump ratio of the solder pastes was low when the carbon numbers of the dicarboxylic acid were 1-3. Spreadability was high when the carbon number was over 2. Zero cross time of wetting balance test was under 1 sec when the carbon number was over 3. When activator was oxalic acid or malonic acid, zero cross time was over 1 sec and maximum wetting force was low. Fluxes with the oxalic acid and malonic acid showed decomposition at the temperature close to melting point. Among the dicarboxylic acids, glutaric acid provided excellent slump, spreadability, and wettability.

키워드

MOKRBW_2018_v25n4_123_f0001.png 이미지

Fig. 1. SMT scope images of a solder paste. (a) 50℃ , (b) 150℃, and (c) 250℃.

MOKRBW_2018_v25n4_123_f0002.png 이미지

Fig. 2. Wetting balance curves of fluxes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).

MOKRBW_2018_v25n4_123_f0003.png 이미지

Fig. 3. Zero cross time (t0) and maximum wetting force (Fmax) of fluxes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).

MOKRBW_2018_v25n4_123_f0004.png 이미지

Fig. 4. SMT scope images of solder pastes at 250℃. The activators in the solder pastes were (a) oxalic acid, (b) malonic acid, (c) succinic acid, (d) glutaric acid, (e) adipic acid, and (f) pimelic acid.

MOKRBW_2018_v25n4_123_f0005.png 이미지

Fig. 5. Slump ratio of solder pastes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).

MOKRBW_2018_v25n4_123_f0006.png 이미지

Fig. 6. Spreadability of solder pastes with carbon number (n) of dicarboxylic acids (HOOC(CH2)nCOOH).

MOKRBW_2018_v25n4_123_f0007.png 이미지

Fig. 7. DSC curves of solder pastes with varying dicarboxylic acid activators. (a) oxalic acid, (b) malonic acid, (c) succinic acid, (d) glutaric acid, (e) adipic acid, and (f) pimelic acid.

MOKRBW_2018_v25n4_123_f0008.png 이미지

Fig. 8. Enthalpy of fluxes calculated from the activation peak of DSC.

Table 1. Properties and structure of dicarboxylic activators in this study.

MOKRBW_2018_v25n4_123_t0001.png 이미지

참고문헌

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