高熔点无铅钎料的研制
摘要
电子工业中电子封装与组装最主要的焊接材料是锡铅合金。但是铅及含铅物为有毒有害物质,钎料在生产及使用过程中危害人体健康,焊接废弃物对环境有着极大的污染。随着人类环保意识的日益增强,大范围内禁止使用含铅物质的呼声越来越高,特别是在日本和欧洲,分别出台了针对消除含铅合金使用的法规,这使得寻找替代有铅钎料的无铅钎料就成为了电子封装中的一个重要课题。至今,已有70多种的无铅焊料合金出现。但是一种普遍使用的高熔点高含铅量的钎料仍然寻找不到合适的替代产品。本文以Bi-Ag为基体,在其基础上加入了一些微量元素,从其基本物理性能、润湿性、界面反应及抗腐蚀性等角度来研究其代替高铅钎料的可行性。
本文首次使用润湿平衡的方法测量了上述钎料的润湿曲线,比较了它们的润湿时间t0和最大润湿力Fmax。结果表明,润湿平衡法可以用来评价这些钎料的润湿性;钎料成分对润湿性能有很大影响,加Zn前,Bi-10Ag-1Cu钎料的润湿性最好,加Zn后,钎料的润湿性能有大幅度地提高。
本文首次测量了上述钎料在铜焊盘的铺展面积。结果表明,在360℃钎焊时,添加Zn之前,Bi-6Ag的铺展面积最小;而Bi-10Ag-1Cu的铺展面积最大。添加Zn后,被测钎料的铺展面积有一定的增减,当Zn含量为1%时,铺展面积达到最大。
本文首次分析了上述钎料与Cu的界面结合情况。结果表明,Bi-Ag以及Bi-Ag-Cu合金体系与Cu基体间并未形成金属间化合物,其结合状态并不属于冶金结合。但是,加入了一定量的Zn后,可以明显的观察到钎料合金有渗入Cu基体的现象,这说明了含Zn的钎料合金与基板之间的结合更加紧密,它们之间有着更强的结合力。
本文还研究了上述钎料钎焊接头在3wt%NaCl溶液中的抗腐蚀性问题,软钎焊焊点抗腐蚀性差的最根本原因是Bi基钎料中能与Cu发生作用的合金元素太少。而含Zn钎料由于金属Zn有着很高的电极电位,因此有存在电化学腐蚀的情况,使其的抗腐蚀性能明显的要弱于Bi-Ag和Bi-Ag-Cu合金体系。
Eutectic Sn-Pb solder is the most widely used in electronic assemblies. The emerging regulations of the worldwide environmental protection, especially in Europe and Japan, have targeted to eliminate the usage of Pb due to the inherent toxicity of Pb. The issues are of importance to explore more suitable Pb-free solders for the application of microelectronics assembly. So far, there have been approximate 70 kinds of Pb-free solder alloy compositions proposed. However, there was a general lack of high-temperature lead-Free solders right now. The purpose of this study is looking for a high-temperature lead-free solder to replace the high Pb solders for high-temperature applications. This study investigated the properties of Bi-Ag alloys, a novel Pb-free solder for high-temperature applications.
The wetting curves of the aforementioned solders were measured by wetting balance for the first time, from which the wetting times and wetting forces of wetting process were obtained and compared with each other. The results show that wetting balance can be used to evaluate the wettability of these solders totally. And, the solders composition had a great effect on the wettability. Among all the candidates, the Bi-10Ag-1Cu solder has the best wettability, and besides, the wettability of all the solders was improved obviously after the addition of Zn.
For the first time, the areas-of-spread on Cu pad of the aforementioned solders were measured. The results showed that the area-of-spread was the smallest for Bi-6Ag and the largest for Bi-10Ag-1Cu when soldering at 360℃before adding Zn. The areas increased significantly after addition Zn for all the solders. The arers-of-spead become the largest when the content of Zn was up to 1%.
The interfaces of the solders/Cu were studied for the first time. The results showed that there was no IMC at the interface for Bi-Ag and Bi-Ag-Cu alloy systems. There was no metallurgical combination in their connections. However, it was clearly observed that the solder alloy come into the Cu pad by adding a certain amount of Zn into solders. It showed that the combination force of Zn-containing solder alloy and substrate was larger than the others.
Also the corrosion resistance of solder joints in 3wt% NaCl solution was studied in this paper. The key reason of poor corrosion resistance of solder joints was the lack of the elements which could interact with Cu in Bi-based solders. For Zn-containing solders, the solder joints could increase the electrochemical corrosion due to the high potential of Zn metal electrode. So, their corrosion resistances were clear weaker than Bi-Ag and Bi-Ag-Cu alloy systems.
本文首次使用润湿平衡的方法测量了上述钎料的润湿曲线,比较了它们的润湿时间t0和最大润湿力Fmax。结果表明,润湿平衡法可以用来评价这些钎料的润湿性;钎料成分对润湿性能有很大影响,加Zn前,Bi-10Ag-1Cu钎料的润湿性最好,加Zn后,钎料的润湿性能有大幅度地提高。
本文首次测量了上述钎料在铜焊盘的铺展面积。结果表明,在360℃钎焊时,添加Zn之前,Bi-6Ag的铺展面积最小;而Bi-10Ag-1Cu的铺展面积最大。添加Zn后,被测钎料的铺展面积有一定的增减,当Zn含量为1%时,铺展面积达到最大。
本文首次分析了上述钎料与Cu的界面结合情况。结果表明,Bi-Ag以及Bi-Ag-Cu合金体系与Cu基体间并未形成金属间化合物,其结合状态并不属于冶金结合。但是,加入了一定量的Zn后,可以明显的观察到钎料合金有渗入Cu基体的现象,这说明了含Zn的钎料合金与基板之间的结合更加紧密,它们之间有着更强的结合力。
本文还研究了上述钎料钎焊接头在3wt%NaCl溶液中的抗腐蚀性问题,软钎焊焊点抗腐蚀性差的最根本原因是Bi基钎料中能与Cu发生作用的合金元素太少。而含Zn钎料由于金属Zn有着很高的电极电位,因此有存在电化学腐蚀的情况,使其的抗腐蚀性能明显的要弱于Bi-Ag和Bi-Ag-Cu合金体系。
Eutectic Sn-Pb solder is the most widely used in electronic assemblies. The emerging regulations of the worldwide environmental protection, especially in Europe and Japan, have targeted to eliminate the usage of Pb due to the inherent toxicity of Pb. The issues are of importance to explore more suitable Pb-free solders for the application of microelectronics assembly. So far, there have been approximate 70 kinds of Pb-free solder alloy compositions proposed. However, there was a general lack of high-temperature lead-Free solders right now. The purpose of this study is looking for a high-temperature lead-free solder to replace the high Pb solders for high-temperature applications. This study investigated the properties of Bi-Ag alloys, a novel Pb-free solder for high-temperature applications.
The wetting curves of the aforementioned solders were measured by wetting balance for the first time, from which the wetting times and wetting forces of wetting process were obtained and compared with each other. The results show that wetting balance can be used to evaluate the wettability of these solders totally. And, the solders composition had a great effect on the wettability. Among all the candidates, the Bi-10Ag-1Cu solder has the best wettability, and besides, the wettability of all the solders was improved obviously after the addition of Zn.
For the first time, the areas-of-spread on Cu pad of the aforementioned solders were measured. The results showed that the area-of-spread was the smallest for Bi-6Ag and the largest for Bi-10Ag-1Cu when soldering at 360℃before adding Zn. The areas increased significantly after addition Zn for all the solders. The arers-of-spead become the largest when the content of Zn was up to 1%.
The interfaces of the solders/Cu were studied for the first time. The results showed that there was no IMC at the interface for Bi-Ag and Bi-Ag-Cu alloy systems. There was no metallurgical combination in their connections. However, it was clearly observed that the solder alloy come into the Cu pad by adding a certain amount of Zn into solders. It showed that the combination force of Zn-containing solder alloy and substrate was larger than the others.
Also the corrosion resistance of solder joints in 3wt% NaCl solution was studied in this paper. The key reason of poor corrosion resistance of solder joints was the lack of the elements which could interact with Cu in Bi-based solders. For Zn-containing solders, the solder joints could increase the electrochemical corrosion due to the high potential of Zn metal electrode. So, their corrosion resistances were clear weaker than Bi-Ag and Bi-Ag-Cu alloy systems.
引文
1 Directive 2002/96/EC of the European Parliament and of the Council of 27 January 2003 on Waste Electrical and Electronic Equipment (WEEE), Official Journal of the European Union, L37, 2003:24~38
2 Directive 2002/96/EC of the European Parliament and of the Council of 27 January 2003 on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment, Official Journal of the European Union, L37, 2003:19~23
3田民波.电子封装工程.清华大学出版社, 2003:45
4张成敬,王春青.陶瓷阵列封装的两种形式及其接口可靠性.电子工业专用设备. 2006,35(8)
5马鑫,何鹏.无铅化电子组装技术.哈尔滨工业大学出版社, 2006
6 S. Green, D. Lea and C. Hunt, NPL Report CMMT(A)213, 1999:1~10
7 I. Atari, A. M. Jackson and P. T. Viacom, Journal of Electronic Materials, 1994, 23(8):757~764
8杨邦朝,顾永莲无铅钎料的研究-.反应润湿行电子封装技术.电子科技大学2006:54~67
9杨邦朝,任辉,苏宏无铅钎料反应润湿性的研究-物理性质与界面反应.电子封装技术.电子科技大学2006:58~63
10 G. L. Ginsberg and D. P. Schnorr, Multichip Modules and Related Technologies (New York: McGraw-Hill Inc., 1994), p. 19
11 M. McCormack and S. Jin, JOM 45, 1993:36
12 J. Kloeser, F. Bechtold, and H. Reichl, IEEE CPMT 19A, 1996:24
13 T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, MaterialsPark, OH, 1990:433.
14 D. Kim, C.C. Lee, Mater. Sci. Eng. A 416 2005:74~79.
15 Jeong-Won Yoon, Hyun-Suk Chun, Seung-Boo Jung. Liquid-State and solid-state interfacial reactions of flux less-bonded Au-20Sn/ENIG solder joint. Journal of Alloys and Compounds 23 2008:423~430
16 J. W. Ronnie Teo, F. L. Ng, L. s. Kip Goi, Y. F. Sun, Z. F. Wang, X. Q. Shi, J. Wei, G. Y. Li, Microstructure of eutectic 80Au-20Sn solder joint in laser diode package,Microelectronic Engineering 85 2008:512~517
17 F. G. Yost, M. M. Karnowsky, W. D. Drotning, J. H. Gieske, MetallTrans. A 21 (99)
18 T. Yamada, K. Miura, M. Kajihara, N. Kurokawa, K. Sakamoto, Mater. Sci. Eng. A 390 2005: 118.
19 S. W. Yoon, W. K. Choi, H.M. Lee, Scripta Mater. 40 1999:297.
20张启运,庄鸿寿.钎焊手册.机械工业出版社, 1999:125~133
21 M. Rettenmayr, P. Lambracht, B. Kempf, and C. Tschudin. Zn-Al Based Alloys as Pb-Free Solders for Die Attach. Journal of Electronic Materials, Vol. 31, No.42002
22 T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, J. Electron.Mater. 28, 1172 1999
23 T. Shimizu, H. Ishikaw,I. Ohnuma, and K. Ishid. Zn-AI-Mg-Ga Alloys as Pb-Free Solder for Die-Attaching Use Journal of ELECTRONIC MATERIALS, , 1999,28(11)
24 Namhyun Kang, Hye Sung Na, Seong Jun Kim, Chung Yun Kang Alloy design of Zn–Al–Cu solder for ultra high temperatures Journal of Alloys and Compounds 220 2008:456~679
25 Yoshickau Takaku, Lazuardi Felicia, Ikuo Hnuma, Ryosuke Kainuma, and Kiyohito Ishida Interfacial Reaction Between Cu Substrates and Zn-Al Base High-Temperature Pb-Free Solders Journal of ELECTRONIC MATERIALS 2007
26 B. K. Prasad, A. K. Patwardhan, and A. H. Yegneswaran Tensile Properties of Some Copper- and Zinc-Based Alloys: Effects of Strain Rate and Test Temperature JMEPEG (000):688~699
27 L. N. Lalena, N.F. Dean, and M.W. Weiser, J. Electron. Mater. 31, 1244 (2002).
28 J. H. Kim, S. W. Jeong, and H. M. Lee, Mater. Trans. 43, 2002:1873
29 T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, J. Electron. Mater. 28, 1999:1172
30 T. B. Massalski, ed., Binary Alloy Phase Diagrams, 2nd ed.(Materials Park, OH: ASM International), 1992:768~769.
31 J. M. Song, H. Y. Chuang, Z.M. Wu, and G.W. Lee, Journal of Taiwan Vacuum Society 18, 8 2006.
32 L. N. Lalena, N. F. Dean, and M. W. Weiser: J. Electron. Mater.,2002, 31(1244).
33 J. M. Song, H. Y. Chuang, and T. X. Wen Thermal and Tensile Properties of Bi-Ag Alloys The Minerals, Metals & Materials Society and ASM International 2007
34 Mulugeta Abtew, Guna selvaduray. Lead-free solders in microelectronics. Materials Science and Engineering, 2000:95~141
35 P. T. Vianco, J. A. Rejent.Properties of ternary Sn-Ag-Bi solder alloys: part 1thermal properties and microstructural analysis.J.Electron.Mater, 1999:1127~1136
36 Mei Z, Morris J. W. High Temperature Deformation of Polycrystalline Sn-Bi solid of bet Structure.J.Electron. Mater, 1992:599~607
37于大全.电子封装互连无铅钎料及其界面问题研究:(博士学位论文).大连:大连理工大学, 2004
38 S. P. Yu, Lin H J. Effect of process parameters on the soldering behavior of the eutectic Sn-Zn solders on Cu substrate. J Mater Sci, 2000, 11:461-471
39中华人民共和国国家标准,硬质合金常温冲击韧性实验方法GB/T 1817-1995
40王凤江.基于纳米压痕技术的无铅BGA焊点力学性能及其尺寸效应:(博士学位论文).哈尔滨:哈尔滨工业大学,2006
41 Tabor D. Indentation hardness: Fifty years on a per2 sonal view[J ] . Philo Mag A , 1996: 1207 ~1212.
42 Suresh S, Alcala J, Giannakopoulos A. E. Spherical in2 dentition of compositionally graded materials : Theory and experiment s [ J ] . Acta Materialia , 1997 : 1307~ 1321.
43 Oliver W C, Pharr G M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiment s [J ] . J Mater Rees , 1992 : 1564 ~1583.
44 Bolshakov A, Pharr G M. Influences of pileup on the measurement of mechanical properties by load and depth sensing indentation techniques[J ] . J Mater Res , 1998: 1049~1058.
45王凤江,钱乙余,马鑫微观压痕法测量Sn2Ag2Cu系无铅钎料的力学性能中国有色金属学报2003,15(15)
46王春青,李明雨,田艳红,孔令超. J IS Z 3198无铅钎料试验方法简介与评述.电子工艺技术. 2004:18~20
47李明雨.钎料液滴激光强迫超声振动及对钎料润湿的影响.哈尔滨工业大学博士论文. 2001:17
48周玉,武高辉.材料分析测试技术-材料X射线衍射与电子显微分析.哈尔滨工业大学出版社, 1997:183~185
2 Directive 2002/96/EC of the European Parliament and of the Council of 27 January 2003 on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment, Official Journal of the European Union, L37, 2003:19~23
3田民波.电子封装工程.清华大学出版社, 2003:45
4张成敬,王春青.陶瓷阵列封装的两种形式及其接口可靠性.电子工业专用设备. 2006,35(8)
5马鑫,何鹏.无铅化电子组装技术.哈尔滨工业大学出版社, 2006
6 S. Green, D. Lea and C. Hunt, NPL Report CMMT(A)213, 1999:1~10
7 I. Atari, A. M. Jackson and P. T. Viacom, Journal of Electronic Materials, 1994, 23(8):757~764
8杨邦朝,顾永莲无铅钎料的研究-.反应润湿行电子封装技术.电子科技大学2006:54~67
9杨邦朝,任辉,苏宏无铅钎料反应润湿性的研究-物理性质与界面反应.电子封装技术.电子科技大学2006:58~63
10 G. L. Ginsberg and D. P. Schnorr, Multichip Modules and Related Technologies (New York: McGraw-Hill Inc., 1994), p. 19
11 M. McCormack and S. Jin, JOM 45, 1993:36
12 J. Kloeser, F. Bechtold, and H. Reichl, IEEE CPMT 19A, 1996:24
13 T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, MaterialsPark, OH, 1990:433.
14 D. Kim, C.C. Lee, Mater. Sci. Eng. A 416 2005:74~79.
15 Jeong-Won Yoon, Hyun-Suk Chun, Seung-Boo Jung. Liquid-State and solid-state interfacial reactions of flux less-bonded Au-20Sn/ENIG solder joint. Journal of Alloys and Compounds 23 2008:423~430
16 J. W. Ronnie Teo, F. L. Ng, L. s. Kip Goi, Y. F. Sun, Z. F. Wang, X. Q. Shi, J. Wei, G. Y. Li, Microstructure of eutectic 80Au-20Sn solder joint in laser diode package,Microelectronic Engineering 85 2008:512~517
17 F. G. Yost, M. M. Karnowsky, W. D. Drotning, J. H. Gieske, MetallTrans. A 21 (99)
18 T. Yamada, K. Miura, M. Kajihara, N. Kurokawa, K. Sakamoto, Mater. Sci. Eng. A 390 2005: 118.
19 S. W. Yoon, W. K. Choi, H.M. Lee, Scripta Mater. 40 1999:297.
20张启运,庄鸿寿.钎焊手册.机械工业出版社, 1999:125~133
21 M. Rettenmayr, P. Lambracht, B. Kempf, and C. Tschudin. Zn-Al Based Alloys as Pb-Free Solders for Die Attach. Journal of Electronic Materials, Vol. 31, No.42002
22 T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, J. Electron.Mater. 28, 1172 1999
23 T. Shimizu, H. Ishikaw,I. Ohnuma, and K. Ishid. Zn-AI-Mg-Ga Alloys as Pb-Free Solder for Die-Attaching Use Journal of ELECTRONIC MATERIALS, , 1999,28(11)
24 Namhyun Kang, Hye Sung Na, Seong Jun Kim, Chung Yun Kang Alloy design of Zn–Al–Cu solder for ultra high temperatures Journal of Alloys and Compounds 220 2008:456~679
25 Yoshickau Takaku, Lazuardi Felicia, Ikuo Hnuma, Ryosuke Kainuma, and Kiyohito Ishida Interfacial Reaction Between Cu Substrates and Zn-Al Base High-Temperature Pb-Free Solders Journal of ELECTRONIC MATERIALS 2007
26 B. K. Prasad, A. K. Patwardhan, and A. H. Yegneswaran Tensile Properties of Some Copper- and Zinc-Based Alloys: Effects of Strain Rate and Test Temperature JMEPEG (000):688~699
27 L. N. Lalena, N.F. Dean, and M.W. Weiser, J. Electron. Mater. 31, 1244 (2002).
28 J. H. Kim, S. W. Jeong, and H. M. Lee, Mater. Trans. 43, 2002:1873
29 T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, J. Electron. Mater. 28, 1999:1172
30 T. B. Massalski, ed., Binary Alloy Phase Diagrams, 2nd ed.(Materials Park, OH: ASM International), 1992:768~769.
31 J. M. Song, H. Y. Chuang, Z.M. Wu, and G.W. Lee, Journal of Taiwan Vacuum Society 18, 8 2006.
32 L. N. Lalena, N. F. Dean, and M. W. Weiser: J. Electron. Mater.,2002, 31(1244).
33 J. M. Song, H. Y. Chuang, and T. X. Wen Thermal and Tensile Properties of Bi-Ag Alloys The Minerals, Metals & Materials Society and ASM International 2007
34 Mulugeta Abtew, Guna selvaduray. Lead-free solders in microelectronics. Materials Science and Engineering, 2000:95~141
35 P. T. Vianco, J. A. Rejent.Properties of ternary Sn-Ag-Bi solder alloys: part 1thermal properties and microstructural analysis.J.Electron.Mater, 1999:1127~1136
36 Mei Z, Morris J. W. High Temperature Deformation of Polycrystalline Sn-Bi solid of bet Structure.J.Electron. Mater, 1992:599~607
37于大全.电子封装互连无铅钎料及其界面问题研究:(博士学位论文).大连:大连理工大学, 2004
38 S. P. Yu, Lin H J. Effect of process parameters on the soldering behavior of the eutectic Sn-Zn solders on Cu substrate. J Mater Sci, 2000, 11:461-471
39中华人民共和国国家标准,硬质合金常温冲击韧性实验方法GB/T 1817-1995
40王凤江.基于纳米压痕技术的无铅BGA焊点力学性能及其尺寸效应:(博士学位论文).哈尔滨:哈尔滨工业大学,2006
41 Tabor D. Indentation hardness: Fifty years on a per2 sonal view[J ] . Philo Mag A , 1996: 1207 ~1212.
42 Suresh S, Alcala J, Giannakopoulos A. E. Spherical in2 dentition of compositionally graded materials : Theory and experiment s [ J ] . Acta Materialia , 1997 : 1307~ 1321.
43 Oliver W C, Pharr G M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiment s [J ] . J Mater Rees , 1992 : 1564 ~1583.
44 Bolshakov A, Pharr G M. Influences of pileup on the measurement of mechanical properties by load and depth sensing indentation techniques[J ] . J Mater Res , 1998: 1049~1058.
45王凤江,钱乙余,马鑫微观压痕法测量Sn2Ag2Cu系无铅钎料的力学性能中国有色金属学报2003,15(15)
46王春青,李明雨,田艳红,孔令超. J IS Z 3198无铅钎料试验方法简介与评述.电子工艺技术. 2004:18~20
47李明雨.钎料液滴激光强迫超声振动及对钎料润湿的影响.哈尔滨工业大学博士论文. 2001:17
48周玉,武高辉.材料分析测试技术-材料X射线衍射与电子显微分析.哈尔滨工业大学出版社, 1997:183~185