무전해 니켈ㆍ 팔라듐 ㆍ 금도금 표면처리 공정의 도금 번짐 불량 및 개선

엄기헌; 서정욱; 원용선; Ki Heon Eom; Jung-wook Seo; Yong Sun Won

Clean Technology, Vol.19, No.2, 84-89, June, 2013

Prevention of Running Blots between the Patterns during the Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) Surface Finish

엄기헌, 서정욱¹, 원용선^†

부경대학교 화학공학과, 608-739 부산광역시 남구 용당동 산 100
¹삼성전기주식회사 생산기술센터, 443-743 경기도 수원시 영통구 매탄 3동 314

Ki Heon Eom, Jung-wook Seo¹, and Yong Sun Won^†

Department of Chemical Engineering, Pukyong National University, San 100 Yongdang-dong, Nam-gu, Busan 608-739, Korea
¹Manufacturing & Engineering Center, Samsung Electro-Mechanics Co., Ltd., 314 Maetan 3-dong, Yeongtong-gu, Suwon-si, Gyunggi 443-743, Korea

E-mail:

초록

무전해 니켈.팔라듐.금 표면처리 공정의 도금 번짐 불량의 근본적인 원인을 이해하고 이를 해결하기 위한 방법을 제시하였다. 이에 계산화학을 이용하여 공정을 정성적으로 설명하고 이를 바탕으로 가정을 검증하기 위한 실험을 계획하였다. 도금 번짐으로 발전되는 고분자 레진 위의 팔라듐 시드의 핵 생성을 막는 것에 초점을 맞추어 고분자 레진과 화학적으로 결합력이 약한 PdCl2 팔라듐 촉매를 도입하였으며 이 촉매가 수용액 중에서 추가적인 가수분해 반응으로 더 안정한 Pd(OH)2를 형성함으로써 고분자 레진 위에 팔라듐 시드의 원천으로 작용하지 않도록 염산(HCl)의 농도를 높이거나 팔라듐 활성화 공정의 온도를 낮추어 보았다. 계산화학은 매 단계 실험의 이론적인 근거를 제시해 주었으며 실험 결과를 해석하는 데 큰 도움을 주었다. 이와 같이 실험과 이론을 접목시킨 본 연구의 접근법은 관련 공정에서 매우 유용하게 활용될 수 있을 것으로 기대된다.

The running blots between patterns during electroless nickel electroless palladium immersion gold (ENEPIG) surface finish of printed circuit board (PCB) are investigated and a proper solution is presented. Computational chemistry is first employed to understand the process and experiments are then designed to verify the proposed ideas. A PdCl2 activator which has relatively weak chemical bonding to the epoxy resin is introduced to prevent the formation of palladium seeds on the epoxy resin and a couple of operational measures such as increasing HCl concentration and lowering the temperature of Pd activation process are executed to prevent a further hydrolysis of PdCl2 to more stable Pd(OH)2 in aqueous solution. Computational chemistry provides thermodynamic backgrounds for experiments and their results. This combined approach is expected to be very useful in the research of relevant processes.

Keywords:Electroless nickel electroless palladium immersion gold (ENEPIG);Printed circuit board (PCB);Pd activator;Computational chemistry;Density functional theory

[References]

http://www.pcb007.com/pages/zone.cgi?a=45348&artpg=1&topic=0
Yee DKW, “Is Electroless Nickel/Electroless Palladium/Imersion Gold (ENEPIG) the Solution of Lead Free Soldering on PCB and IC Packaging Applications?” Microsystems, Packaging, Assembly and Circuits Technology in IMPACT 2007, Taipei, 208 (2007)
Juanjuan L, Zhenging Z, Lee J, “Wire Bonding Performance and Solder Joint Reliability Investigation on ENEPIG Finish Substrate,” 2010 11th International Conference on Electronic Packaging Technology & High Density Packaging (ICEPT-HDP), Xi'an, 240 (2010)
Yoon JW, Noh BI, Jung SB, J. Electron. Mater., 40, 1951 (2011)
http://www.kitco.com/charts
Won YS, Park SS, Lee J, Kim JY, Lee SJ, Appl. Surf. Sci., 257(1), 56 (2010)
Hohenberg P, Kohn W, Phys. Rev., 136, B864 (1964)
Becke AD, J. Chem. Phys., 98, 5648 (1993)
Ditchfield R, Herhe WJ, Pople JA, J. Chem. Phys., 54, 724 (1971)
Gaussian 09W, Revision C.01, Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Eds., Gaussian, Inc., Wallingford CT (2009)
Kaja S, Mukherjee SP, O'Sullivan EJ, Paunovic M, “Palladium Sulfate Solution for the Selective Seeding of the Metal Interconnections on Polyimide Dielectrics for Electroless Metal Deposition,” U.S. Patent No. 5,380,560 (1995)
Watanabe K, Nishiwaki T, Honma H, “Evaluation of Activation Solution on Selective Electroless Nickel Deposition," 55th Annual Meeting of International Society of Electrochemistry, Thessaloniki (2004)
Boily JF, Seward TM, Geochimica et Cosmochimica Acta., 69, 3773 (2005)
Simonov PA, Troitskii SY, Likholobov VA, Kinetics Catal., 41, 255 (2000)

[1] http://www.pcb007.com/pages/zone.cgi?a=45348&artpg=1&topic=0

[2] Yee DKW, “Is Electroless Nickel/Electroless Palladium/Imersion Gold (ENEPIG) the Solution of Lead Free Soldering on PCB and IC Packaging Applications?” Microsystems, Packaging, Assembly and Circuits Technology in IMPACT 2007, Taipei, 208 (2007)

[3] Juanjuan L, Zhenging Z, Lee J, “Wire Bonding Performance and Solder Joint Reliability Investigation on ENEPIG Finish Substrate,” 2010 11th International Conference on Electronic Packaging Technology & High Density Packaging (ICEPT-HDP), Xi'an, 240 (2010)

[4] Yoon JW, Noh BI, Jung SB, J. Electron. Mater., 40, 1951 (2011)

[5] http://www.kitco.com/charts

[6] Won YS, Park SS, Lee J, Kim JY, Lee SJ, Appl. Surf. Sci., 257(1), 56 (2010)

[7] Hohenberg P, Kohn W, Phys. Rev., 136, B864 (1964)

[8] Becke AD, J. Chem. Phys., 98, 5648 (1993)

[9] Ditchfield R, Herhe WJ, Pople JA, J. Chem. Phys., 54, 724 (1971)

[10] Gaussian 09W, Revision C.01, Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Eds., Gaussian, Inc., Wallingford CT (2009)

[11] Kaja S, Mukherjee SP, O'Sullivan EJ, Paunovic M, “Palladium Sulfate Solution for the Selective Seeding of the Metal Interconnections on Polyimide Dielectrics for Electroless Metal Deposition,” U.S. Patent No. 5,380,560 (1995)

[12] Watanabe K, Nishiwaki T, Honma H, “Evaluation of Activation Solution on Selective Electroless Nickel Deposition," 55th Annual Meeting of International Society of Electrochemistry, Thessaloniki (2004)

[13] Boily JF, Seward TM, Geochimica et Cosmochimica Acta., 69, 3773 (2005)

[14] Simonov PA, Troitskii SY, Likholobov VA, Kinetics Catal., 41, 255 (2000)