通信论文微电子封装中化学镀NI.doc

《通信论文微电子封装中化学镀NI.doc》由会员分享，可在线阅读，更多相关《通信论文微电子封装中化学镀NI.doc（4页珍藏版）》请在三一办公上搜索。

1、微电子封装中化学镀Ni 微电子封装中化学镀Ni-P薄膜研究 Study on Electroless Ni-P Film Plating in Microelectronic Packaging【中文摘要】 随着科技的发展,电子产品越来越趋于小型化,电子器件焊点的结构和形态也发生了的巨大变化,组装密度大幅度提高,微电子封装已成为当今电子工业中最重要和最具挑战的技术之一。钎料作为一种连接材料,在微电子封装中,发挥着至关重要的作用,钎料合金与UBM扩散阻挡层之间的界面反应是影响焊点可靠性的关键所在。化学镀Ni-P是一种优异的钎焊阻挡层材料,具有良好的可焊性,近年来在微电子封装工业中得到了广泛的应用

2、。本文通过对铝基表面化学镀Ni-P工艺的研究,选择适合的预处理工艺,以获得适用于微电子封装领域的、性能良好Ni-P镀层,并对施镀工艺条件进行优化,实现工艺参数的可控性,对镀层的可靠性进行检测与评价。在获得性能良好的化学镀Ni-P镀层的基础上,研究化学镀Ni-P与Sn-3.5Ag钎料之间在钎焊和时效过程中的界面反应,以及界面处IMC生长规律,并讨论化学镀Ni-P在钎焊及时效过程中的成分变化。研究结果如下:1.对于铝基表面的镀前预处理,经过对传统高、中、低浓度浸锌溶液的对比,得到组成为氢氧化钠120g/L,氧化锌20g/L,酒石酸钾纳20g/L,三氯化铁2g/L,硝酸钠1g/L的中浓度浸锌液最适合

3、本研究;通过对比不同浓度HNO3和HCl退锌后基体的腐蚀程度与退锌效果,得出当采用浓度为10%的HNO3退锌,操作时间为56s时,即可退去一次浸锌层,对基体的腐蚀程度也最轻;通过对二次浸锌时间的研究,得到二次浸锌30s时,锌颗粒已基本将基体完全覆盖,且锌层呈单层排列。2.通过正交试验的方法对苹果酸-丁二酸体系中化学镀Ni-P镀液成分和pH对镀层成分及镀速的影响的研究得出:施镀温度为90,镀液的pH值是影响镀层P含量和镀速的最重要因素,其次是主盐NiSO4和还原剂NaH2PO2的浓度,络合剂的浓度改变对镀速和镀层成分的影响较小。对于选定成分的酸性(3.5pH6)镀液,随镀液pH值的增大,镀层的磷

4、含量由22.5 at.%(pH=3.5)逐渐减低至12.6 at.%(pH=6.0;而镀速随pH值的增大而增加,但只在其小于5时镀速变化明显,pH=5.06.0镀速变化很小,pH=5时镀速达最大值21.0m/h;主盐NiSO4浓度由18g/L增大到28g/L,镀层磷含量由17.2at.%逐渐降低至14at.%,镀速由16.2m/h逐渐升高到21m/h后基本不变;还原剂NaH2PO2浓度由18g/L增大到28g/L,镀层磷含量由12.9at.%逐渐增大至15.6at.%,镀速由18m/h增至23m/h,在NaH2PO2浓度为26g/L时达最大值。研究所获得的镀液稳定性良好;镀层与基体结合能力较好

5、,镀层为非晶结构。3.通过对磷含量分别为6.5wt.%(11.6at.%)和8.5wt.%(15.0at.%)的两种化学镀Ni-P层与Sn-3.5Ag钎料球在钎焊和时效过程中的界面反应,以及界面处IMC生长规律的研究得到:Sn-3.5Ag与两种磷含量的镀层在250钎焊进行钎焊时,润湿角和铺展率均随着钎焊时间的延长而略有减小,但变化很小:Sn-3.5Ag/Ni-P钎焊后界面由钎料到基体依次为Ni3Sn、Ni-Sn-P、Ni3P、Ni-P、Al;两种Ni-P层,时效后IMC的形态都出现了棒状的特征;不同钎焊时间及两种P含量皆未影响到Sn-3.5Ag/Ni-P界面结构,只是在Ni-8.5wt.%P钎

6、焊30min后原始Ni-P层已完全消耗;钎焊5min焊点时效后,IMC层逐渐增厚并发生剥落。同时界面处Ni-Sn-P层、Ni3P层随时效时间延长逐渐增厚;对于Ni-8.5wt.%P,时效200h后,原始Ni-P层完全消耗。【英文摘要】 With the development of technology,the electronic products are tending to miniaturization,and the microstructure and morphology of soldering points are remarkably changed.Packing den

7、sity is obviously increased as well.So the microelectronic packing has become one of the most important and challenging technology in the electronic industry nowadays.As a joining material,solders play an important role in microelectronic packing. And interfacial reaction between the solder alloys a

8、nd the UBM is a critical point for the effect on the reliability.Electroless Ni-P has been widely used in the microelectronic packing in the recent years because of the better solderability and diffusion barrier.The technical investigation on electroless Ni-P on Al substrate was studied in the prese

9、nt work.The objective was to optimize the pretreatment process and gain a Ni-P plating with better properties which is applied to electronic packing,and to find out the controllability of technological parameters by optimizing the plating process.Also the examination and evaluation of reliability we

10、re concluded.After gaining the.electroless Ni-P plating with better properties,the interfacial reaction of Sn-3.5Ag/Ni-P was investigated after soldering and aging in order to explore the growth mechanics of IMC and the change of Ni-P component.The major conclusions are as follows:1.Comparative stud

11、y on conventional high,medium,low concentration of zincating solution was carried out during the pretreatment on AI substrate.And a good zincating solution with the compositions of 120g/L NaOH,20g/L ZnO,20g/L C4H4KNaO64H2O,2g/L FeCl3,1g/L NaNO3 was gained.On the investigation on 1st zincating,a bett

12、er zincating process of 10% HNO3 and operating time of 56s was found by comparing the corrosion and the zincating effect during zincating in different concentration of HNO3 and HCl solution.On the investigation on 2nd zincating,a zincating time of 30s was good.After 2nd zincating for 30s, the surfac

13、e of Al substrate was fully covered by Zn particles and it was a monolayer of Zn.2.In the present work,the mutual effect of concentration of NiSO4,reductant,complexing agent and pH value on the deposition rate and P content was investigated by the orthogonal test. The results shows that the effect o

14、f pH value on the deposition rate and P content is pronounced, and the effect of concentration of NiSO4 and reductant is less pronounced,while the effect of concentration of complexing agent is minor.In the acid solution with the pH value in the range of 3.5 to 6.0,the P content is decreased as the

15、pH value increased from 22.5 at.%(pH=3.5) to 12.6 at.%(pH=6.0).However,the deposition rate is increased with the increasing pH value before the deposition rate reaches the maximum value of 21.0um/h(pH=5.0).The deposition rate remains unchanged when the pH value exceeds 5.0.And the P content is decre

16、ased from 17.2at.%to 12at.%with the increasing concentration of NiSO4 from 18g/L to 28g/L,the deposition rate is increased from 16.um/h to 21um/h as well.When the concentration of NaH2PO2 increased from 18g/L to 28g/L,the P content was increased from 12.9at.%to 15.6at.%and the deposition rate was in

17、creased from 18um/h to 23um/h.At the concentration of 26g/L NaH2PO2,the deposition rate reached the maximum.The gained plating solution has good stability,and after plating,the amorphous Ni-P plating has good adhesion on Al substrate.3.The interfacial reaction of Sn-3.5Ag/Ni-P(Ni-6.5wt.%P,Ni-8.5wt.%

18、P) was investigated during the soldering and aging.The wetting angles and spreading coefficients showed that there was no effect of P content on the wettability though some minor changes were found during soldering at 250.The phases of interface from solder to substrate were Ni3Sn4, Ni-Sn-P,Ni3P and

19、 Ni-P respectively.After aging,rod-like morphology of IMC was appeared. And there was no effect of P content on the microstructure of Sn-3.5Ag/Ni-P interface during soldering for different time,except that Ni-P was absolutely consumed in the case of Ni-8.5wt.%P after 30min soldering.During the aging

20、 of 5min solder point,the thickness of IMC increased with aging time increasing.Meanwhile,the thickness of Ni-Sn-P and Ni3P was thickened with aging time.For Ni-8.5wt.%P,the initial Ni-P plating was absolutely consumed after 200h of aging. 【中文关键词】 微电子封装; 化学镀Ni-P; 界面反应; 预处理 【英文关键词】 Microstructure Pac

21、king; Electroless Ni-P; Interfacial Reaction; Pretreatment 【毕业论文目录】摘要 4-6 Abstract 6-7 1 绪论 11-30 1.1 微电子封装 11-15 1.1.1 微电子封装的层次 11-12 1.1.2 微电子封装技术的发展及其应用 12-15 1.2 钎料在微电子封装中的应用 15-16 1.3 微电子封装中的凸焊点及UBM 16-18 1.4 化学镀Ni-P与钎料之间的界面反应 18-21 1.4.1 化学镀Ni-P与Sn-Ag钎料之间的界面反应 18-20 1.4.2 化学镀Ni-P镀层P含量对钎焊接头的影响

22、20-21 1.5 化学镀Ni-P镀层制备与应用 21-29 1.5.1 化学镀简介 21-22 1.5.2 化学镀机理的几种假说 22-23 1.5.3 化学镀Ni-P的工艺 23-26 1.5.4 化学镀Ni-P在电子工业中的主要应用 26-28 1.5.5 化学镀Ni-P的发展趋势 28-29 1.6 论文主要工作 29-30 2 实验药品、设备及实验方法 30-34 2.1 实验药品 30 2.2 实验材料与设备 30-32 2.2.1 实验材料 30-31 2.2.2 实验设备 31-32 2.3 溶液配制方法 32-33 2.3.1 化学镀Ni-P镀液配置方法 32-33 2.3.

23、2 浸锌液配制方法 33 2.4 金相试样的制备 33-34 3 化学镀Ni-P前处理工艺 34-49 3.1 浸锌液浓度的选择 35-38 3.1.1 实验部分 35-36 3.1.2 实验结果及分析 36-38 3.2 退锌工艺 38-45 3.2.1 退锌溶液浓度的选择 39-40 3.2.2 退锌时间的选择 40-42 3.2.3 盐酸退锌 42-45 3.3 二次浸锌时间的选择 45-47 3.4 一次浸锌、二次浸锌的比较 47-48 3.5 本章小结 48-49 4 化学镀Ni-P薄膜工艺研究 49-65 4.1 镀液组成及试样前处理 49 4.2 正交试验确定各因素对镀层磷含量及

24、镀速的影响 49-53 4.2.1 正交试验设计 49-50 4.2.2 正交试验结果 50-51 4.2.3 正交试验各因素对镀层磷含量的影响 51-52 4.2.4 正交试验各因素对镀速的影响 52-53 4.3 镀液pH对镀速和镀层磷含量的影响 53-57 4.3.1 实验结果 53-55 4.3.2 分析与讨论 55-57 4.4 主盐、还原剂浓度对镀层P含量和镀速的影响 57-59 4.4.1 主盐浓度对镀层P含量和镀速的影响 57-58 4.4.2 还原剂浓度对镀层P含量及镀速的影响 58-59 4.5 镀液稳定性 59-61 4.5.1 测试方法 60 4.5.2 结果与讨论 6

25、0-61 4.6 镀层性能测试 61-63 4.6.1 化学镀Ni-P镀层的外观及表面形貌 61-62 4.6.2 化学镀Ni-P镀层晶体类型分析 62-63 4.6.3 结合力测试 63 4.7 本章小结 63-65 5 化学镀Ni-P与Sn-3.5Ag钎料在钎焊和时效过程中的界面反应 65-76 5.1 Sn-3.5Ag/Ni-P/Al的润湿行为 65-66 5.1.1 两种Ni-P镀层与Sn-3.5Ag的润湿角 65-66 5.1.2 两种Ni-P镀层与Sn-3.5Ag的铺展系数 66 5.2 Sn-3.5Ag/Ni-P钎焊后典型的IMC形貌和结构 66-68 5.3 钎焊时间对Sn-3.5Ag/Ni-P界面反应的影响 68-70 5.4 时效过程中Sn-3.5Ag/Ni-P界面的显微结构 70-74 5.5 时效过程中Sn-3.5Ag/Ni-P的表面形貌 74-75 5.6 本章小结 75-76 结论 76-78 参考文献 78-82 攻读硕士学位期间发表学术论文情况 82-83 致谢 83-84