激光微熔覆导电膜与基板的粘附性及可焊性的研究
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摘要
随着电子行业的飞速发展,对于工业用导电膜层来说,除了经济性、高稳定性、导电率大外,还要求附着牢靠和可焊性好。本文利用激光微熔覆技术在薄膜基板上制备厚膜金层,研究激光加工工艺参数和基板材料性能对激光微熔覆金层与基板的粘附性及可焊性的影响规律,旨在为激光微熔覆技术的应用提供理论参考依据。?
实验结果表明,波长为532nm的激光比波长为1064nm的激光更容易在基板上制备导电金膜。不同基板材料上存在不同的烧结临界功率密度值FⅠ和过烧临界功率密度值FⅡ。在FⅠ~ FⅡ范围内,提高激光功率密度可以提高金膜在基板上的粘附强度。测试标准中粘附等级最高为5B,硅基板上预置厚度为6~8μm的金膜在波长为1064nm,功率密度为1.29×10~6W/cm~2~2.00×10~6W/cm2,扫描速度为1mm/s的激光作用下,金膜粘附强度等级可达4B~5B。导电金膜经过温度范围为500℃~600℃后续处理后,粘附性和可焊性都大幅度提高。
通过SEM、热分析等技术对利用激光微熔覆技术在硅基板上制备的导电金膜进行分析,得出金膜与硅基板的附着机理及金膜可焊性的机理:金在激光辐照作用下与单晶硅基板发生共晶反应,生成Au-Si共晶物,保证了金膜在硅基板上的粘附强度;同时,Au与浆料中的Bi发生共晶反应,生成Au-Bi共晶物,不仅增加了膜层的粘附强度,还有效的阻止了超声铝丝压焊的铝丝向金中的扩散,提高了金膜的可焊性。
With the rapid development of the electronic industry, conductive layers for industrial use, not only requires economic performance, high stability, large electrical conductivity, but also strong adhesion and good solderability. In this paper, an idea of fabricating thick-film gold paste on the substrates which were used in the thin-film technology was proposed. The effect of laser processing parameters, properties of substrates to adhesion on substrate and solderability of laser micro-cladding electronic coating was studied. It aimed at proposing theoretical reference for application of laser micro-cladding technology.
The results showed that it was easier to get gold layers on the substrates for short wavelength (λ=532nm) than long wavelength (λ=1064nm). Gold paste on different substrates had different critical power density of sintered—FⅠ,and critical power density of burned—FⅡ. Increase of laser power density between FⅠand FⅡwas useful to increase the adhesion on substrate of gold layer. The highest level of adhesion testing standard was 5B, the adhesion of 6~8μm thickness of pre-set gold film on silicon could reach 4B~5B under the laser scanning. The parameters of laser were, 1064nm wavelength, 1mm/s scan velocity and 1.29×106W/cm2~2.00×106W/cm2 power density range. For the compactness of coating after laser scanning was less than the high-temperature sintering, the effective of ultrasonic aluminum wire bonding on gold coatings was not good. The laser processing parameters needed to be further explored, but the density of laser micro-cladding electronic coating was improved by subsequent heat treatment (500~600℃), which effectively improved the coating adhesion strength on substrate and solderability.
Through some analysis technology such as SEM, thermal analysis, this paper analyzed the electronic coating on silicon substrate fabricated by laser micro-cladding technology, got the adhesion mechanism of gold coating and silicon and the solderability mechanism of the gold coating: the eutectic reaction occurred between the gold and silicon substrate under laser irradiation. The product from the eutectic reaction ensured the adhesion on silicon substrate of laser micro-cladding gold coating. At the same time, the eutectic reaction also took place between Au and Bi in the coating. The Au-Bi eutectic not only increased the adhesion of coating, but also prevented diffusion of the aluminum wire from the ultrasonic aluminum wire bonding to the gold coating, and improved the solderability of gold coating.
实验结果表明,波长为532nm的激光比波长为1064nm的激光更容易在基板上制备导电金膜。不同基板材料上存在不同的烧结临界功率密度值FⅠ和过烧临界功率密度值FⅡ。在FⅠ~ FⅡ范围内,提高激光功率密度可以提高金膜在基板上的粘附强度。测试标准中粘附等级最高为5B,硅基板上预置厚度为6~8μm的金膜在波长为1064nm,功率密度为1.29×10~6W/cm~2~2.00×10~6W/cm2,扫描速度为1mm/s的激光作用下,金膜粘附强度等级可达4B~5B。导电金膜经过温度范围为500℃~600℃后续处理后,粘附性和可焊性都大幅度提高。
通过SEM、热分析等技术对利用激光微熔覆技术在硅基板上制备的导电金膜进行分析,得出金膜与硅基板的附着机理及金膜可焊性的机理:金在激光辐照作用下与单晶硅基板发生共晶反应,生成Au-Si共晶物,保证了金膜在硅基板上的粘附强度;同时,Au与浆料中的Bi发生共晶反应,生成Au-Bi共晶物,不仅增加了膜层的粘附强度,还有效的阻止了超声铝丝压焊的铝丝向金中的扩散,提高了金膜的可焊性。
With the rapid development of the electronic industry, conductive layers for industrial use, not only requires economic performance, high stability, large electrical conductivity, but also strong adhesion and good solderability. In this paper, an idea of fabricating thick-film gold paste on the substrates which were used in the thin-film technology was proposed. The effect of laser processing parameters, properties of substrates to adhesion on substrate and solderability of laser micro-cladding electronic coating was studied. It aimed at proposing theoretical reference for application of laser micro-cladding technology.
The results showed that it was easier to get gold layers on the substrates for short wavelength (λ=532nm) than long wavelength (λ=1064nm). Gold paste on different substrates had different critical power density of sintered—FⅠ,and critical power density of burned—FⅡ. Increase of laser power density between FⅠand FⅡwas useful to increase the adhesion on substrate of gold layer. The highest level of adhesion testing standard was 5B, the adhesion of 6~8μm thickness of pre-set gold film on silicon could reach 4B~5B under the laser scanning. The parameters of laser were, 1064nm wavelength, 1mm/s scan velocity and 1.29×106W/cm2~2.00×106W/cm2 power density range. For the compactness of coating after laser scanning was less than the high-temperature sintering, the effective of ultrasonic aluminum wire bonding on gold coatings was not good. The laser processing parameters needed to be further explored, but the density of laser micro-cladding electronic coating was improved by subsequent heat treatment (500~600℃), which effectively improved the coating adhesion strength on substrate and solderability.
Through some analysis technology such as SEM, thermal analysis, this paper analyzed the electronic coating on silicon substrate fabricated by laser micro-cladding technology, got the adhesion mechanism of gold coating and silicon and the solderability mechanism of the gold coating: the eutectic reaction occurred between the gold and silicon substrate under laser irradiation. The product from the eutectic reaction ensured the adhesion on silicon substrate of laser micro-cladding gold coating. At the same time, the eutectic reaction also took place between Au and Bi in the coating. The Au-Bi eutectic not only increased the adhesion of coating, but also prevented diffusion of the aluminum wire from the ultrasonic aluminum wire bonding to the gold coating, and improved the solderability of gold coating.
引文
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[6] Zeng Xiaoyan, Li Xiangyou, Liu Jingwei et al. Direct fabrication of electric components on insulated boards by laser micro-cladding electronic pastes. IEEE Transactions on Advanced Packaging, 2006, 29(2): 291~294
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[8] Li Huiling, Zeng Xiaoyan, Li Huifen. Study on thick film resistor and electrode fabricated by laser micro-cladding electronic pastes. Surface and Coating Technology, 2006, 200: 6832~6839
[9] Cai Zhixiang, Li Xiangyou, Hu Qianwu et al. Fabrication of microheater by laser micro cladding electronic paste. Materials Science and Engineering B, 2009, (157) : 15~19
[10] Cai Zhixiang, Li Xiangyou, Zeng Xiaoyan. Direct fabrication of SnO2-based thick film sensor using micropen direct writing and laser microcladding. Sensors and Actuators B: Chemical, 2009, (137): 340~344
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[17]胡奈赛,徐可为,何家文.涂?镀层的结合强度评定.中国表面工程, 1998, 1: 31~35
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[19] Jisheng E, Zhang Aiyang. Aspects of characterisation of thin coating adhesion at the nano-scale. Materials Review, 2002, 16(7): 5~10
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[24]姜银方.关于基片性质对离子镀膜影响的分析.表面技术, 1996, 25(6): 21~24
[25]于喜年.金属防腐涂层附着力影响因素分析.大连铁道学院学报, 2006, 27(2): 42~45
[26]潘永强,卢进军,万径昱.光学塑料真空镀膜附着力机理与工艺研究.应用光学, 2003, 24(3): 32~34
[27]李金华.磷化膜对锌板表面涂层附着力的影响.表面技术, 2006, 35(2): 33~34
[28]程开富.膜层附着力强度分析.四川真空, 1999, (1): 38~40
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[33] Charles A. Harper,电子封装与互连手册.第四版.贾松良,蔡坚,沈卓身等译.北京:电子工业出版社, 2009. 235~317
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[35]马学辉.可焊性?焊接能力和焊点可靠性之评估和测试.印制电路信息, 2007, 7: 60~63
[36]查尔斯A.哈珀(Charles A. Harper).电子封装材料与工艺.原著第三版.沈卓身,贾松良译.北京:化学工业出版社, 2006. 215~495
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[40]李世鸿.厚膜金导体浆料.贵金属, 2001, 22(1): 57~62
[41] Theodore C. Reissing. An overview of today’s thick-film technology. Proceeding of the IEEE, 1972, 59(10): 1448~1454
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[2]祁小敬,刘敬伟,李祥友等.一种激光微细熔覆直写布线的新技术.中国激光, 2004, 31(7): 883~887
[3]陈轶群,李祥友,李慧玲等.激光直写制备厚膜导体技术研究.电子元件与材料, 2004, 23(8): 4~6
[4] Cao Yu, Li Xiangyou, Zeng Xiaoyan. Laser micro-cladding electronic pastes for fabrication of MIM thick film capacitors. Front. Optoelectron. China, 2009, 2(1): 86~91
[5] Li Xiangyou, Li Huiling, Chen Yiqun et al. Silver conductor fabrication by laser direct writing on Al2O3 substrate. Appl. Phys. A. 2004, 79: 1861~1863
[6] Zeng Xiaoyan, Li Xiangyou, Liu Jingwei et al. Direct fabrication of electric components on insulated boards by laser micro-cladding electronic pastes. IEEE Transactions on Advanced Packaging, 2006, 29(2): 291~294
[7]李祥友.激光微细熔覆电子浆料柔性布线技术与设备: [博士论文].武汉:华中科技大学图书馆, 2005
[8] Li Huiling, Zeng Xiaoyan, Li Huifen. Study on thick film resistor and electrode fabricated by laser micro-cladding electronic pastes. Surface and Coating Technology, 2006, 200: 6832~6839
[9] Cai Zhixiang, Li Xiangyou, Hu Qianwu et al. Fabrication of microheater by laser micro cladding electronic paste. Materials Science and Engineering B, 2009, (157) : 15~19
[10] Cai Zhixiang, Li Xiangyou, Zeng Xiaoyan. Direct fabrication of SnO2-based thick film sensor using micropen direct writing and laser microcladding. Sensors and Actuators B: Chemical, 2009, (137): 340~344
[11]蔡志祥.微笔-激光复合直写厚膜传感器的关键技术研究: [博士论文].武汉:华中科技大学, 2009
[12]李慧玲,曾晓雁.激光微细熔覆快速原型制造的厚膜电容组织性能.应用光学. 2006, 27(5): 423~427
[13]李文兵,李祥友,曾晓雁.激光微细熔覆电阻浆料直写电阻技术初步研究.激光技术. 2005, 29(2): 123~125
[14]李慧玲,曾晓雁.后续烧结工艺对激光微细熔覆制备厚膜电阻性能的影响.中国激光. 2006, 23(4): 570~576
[15]陈丽华,吴少英,黄柏龄.浆液粘附性的研究.青岛大学学报, 2000, 15(3): 60~63
[16]宋玉苏,姚树人.涂层与基体金属附着力的研究进展.材料保护, 1999, 32(9): 21~22
[17]胡奈赛,徐可为,何家文.涂?镀层的结合强度评定.中国表面工程, 1998, 1: 31~35
[18]葛继平.镀膜结合强度测试技术的研究进展.中国表面工程. 1995, 16(2): 43~48
[19] Jisheng E, Zhang Aiyang. Aspects of characterisation of thin coating adhesion at the nano-scale. Materials Review, 2002, 16(7): 5~10
[20]刘长清,金柱京,于力等. PVD薄膜的粘附性和塑韧性评估.金属学报, 1992, 28(4): 173~178
[21]易茂中,冉丽萍,何家文.厚涂层结合强度测定方法研究进展.表面技术, 1998, 2(27): 33~37
[22]马峰,蔡珣.膜基界面结合强度表征和评价.表面技术, 2001, 30(5): 15~19
[23] Suga Y, Lian D. Ultrosonic testing method for detecting delamination of sprayed ceramic coating. In: Proceeding of 14th ITSC. Japan, 1995. 961~965
[24]姜银方.关于基片性质对离子镀膜影响的分析.表面技术, 1996, 25(6): 21~24
[25]于喜年.金属防腐涂层附着力影响因素分析.大连铁道学院学报, 2006, 27(2): 42~45
[26]潘永强,卢进军,万径昱.光学塑料真空镀膜附着力机理与工艺研究.应用光学, 2003, 24(3): 32~34
[27]李金华.磷化膜对锌板表面涂层附着力的影响.表面技术, 2006, 35(2): 33~34
[28]程开富.膜层附着力强度分析.四川真空, 1999, (1): 38~40
[29]胡忠谞,恽正中,杨邦朝等.薄厚膜混合集成电路.第一版.北京:国防工业出版社, 1982. 12~20
[30] James J. Licari, Leonard R. Enlow.混合微电路技术手册——材料?工艺?设计?试验和生产.第二版.朱瑞廉译.北京:电子工业出版社, 2004. 73~209
[31]王听岳.膜电路导体的焊接性.焊接, 2001, (1): 14~16
[32]吴懿平.可焊性及其评价方法.环球SMT与封装(特邀稿), 2006
[33] Charles A. Harper,电子封装与互连手册.第四版.贾松良,蔡坚,沈卓身等译.北京:电子工业出版社, 2009. 235~317
[34]姚志刚.焊接性能的考核方法.半导体技术, 1984, 3: 30~32
[35]马学辉.可焊性?焊接能力和焊点可靠性之评估和测试.印制电路信息, 2007, 7: 60~63
[36]查尔斯A.哈珀(Charles A. Harper).电子封装材料与工艺.原著第三版.沈卓身,贾松良译.北京:化学工业出版社, 2006. 215~495
[37] Hoboken, N. J. Handbook of thick and thin film hybrid microelectronics. First Edition. New Jersey: JOHN WILEY & SONS. INC. Hoboken, 2003. 161~174
[38]李耀霖.厚膜电子元件.第一版.广东:华南理工大学出版社, 1991. 3~4
[39]李慧玲,曾晓雁.搭接量对激光微细熔覆柔性直写厚膜电阻组织性能的影响.中国激光, 2005, 32(11): 1554~1560
[40]李世鸿.厚膜金导体浆料.贵金属, 2001, 22(1): 57~62
[41] Theodore C. Reissing. An overview of today’s thick-film technology. Proceeding of the IEEE, 1972, 59(10): 1448~1454
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