无铅银浆烧结工艺与导电性能研究

制备了无铅低温玻璃粉,将其与银粉和有机载体混合配制成无铅导电银浆并烧结。通过SEM和EDX观察浆料烧结银膜的形貌并进行成分分析,用四探针测试仪测量烧结银膜的电阻率,讨论了浆料成分配比、烧结时间、烧结温度等方面对银膜导电性能的影响。确定了无铅导电银浆的最佳配比为:质量分数w(银粉)72%,w(玻璃粉)3%和w(有机载体)25%,最佳烧结温度为580℃,最佳保温时间为5min。     

低温固化型银基浆料电性能的研究

用银粉、热固性环氧树脂、六氢苯酐和环氧改性剂制得了在180℃固化的银基浆料。研究了银粉含量、银粉比例、环氧树脂含量、硅烷偶联剂用量以及固化时间对银基浆料性能的影响。结果表明:银粉含量及形状、固化时间等均会影响浆料性能。当w(环氧树脂)为8%～10%;w(银粉)为65%～70%,ζ(片状银粉∶球状银粉)为8∶2;w(硅烷偶联剂)为6%;w(各种添加剂)为14%～22%;固化时间为15min时,浆料的体电阻率最小为2.25×10–5Ω·cm,方阻为7.03mΩ/□。     

银粉的形状对低温固化导电银浆导电性能的影响

研究了银粉含量、形状、表面处理工艺对低温固化导电银浆导电性能的影响。结果显示,最理想的银粉质量含量在65%~70%之间。同时,鳞片状银粉和球形粉的混合体制成的浆料导电性能最佳。另外,最好的固化条件是150℃、2 h。     

导电银胶触变性的研究

以环氧树脂为基体,银粉为填料,制备出IC封装用导电银胶。研究了环氧树脂与银粉的比例、银粉的形貌和粒径以及触变剂SiO2的用量对导电银胶触变性的影响。结果表明,银胶触变性随树脂/银粉质量比的减小而增大,当其为0.2时,触变指数达到5.68。在一定粒径范围内,银胶的触变性与银粉粒径呈反比关系;银胶触变性随SiO2的用量增大而增大。     

纳米银粉在低温银浆中的烧结工艺研究

为了在柔性基材上获得导电性良好的导电线路,以直流电弧等离子体蒸发凝聚法制备了纳米银粉,并以其作为导电功能相制备了低温银浆,对其烧结工艺展开了研究。结果表明所制的银粉为一种球形度高、结晶性良好、不同大小纳米颗粒复合的粉体,以其制备的银浆在250~300℃烧结即可形成导电性膜层,且烧结温度越高,所得膜层方阻越低。但烧结温度较高时,需缩短烧结时间,以避免膜层剧烈收缩产生的裂纹降低膜层的导电性。所制银浆经300℃烧结30 min所得膜层的导电性最好,方阻可低至8.8 m?/□。     

固体钽电解电容器用耐浸焊性银浆的研究

研究的银浆选用片状银粉作导电填料,其松装密度1.20～1.70g/cm~3,平均粒度<5μm,在电镜视场下显半透明状。选用改性聚甲基丙烯酸甲酯(PMMA)树脂,再加适当的交联改性剂及偶联剂等。银浆固化温度130～150℃;体积电阻率ρ_v≤1.0×10 ~4Ω·cm;在205～210℃的2Ag 36Pb 62Sn焊料中5～7s,浸焊性良好;抗剪切力>186N/cm~2。能满足引进生产线150℃固化,197～205℃、5s浸焊的要求。电容器损耗tgδ值小,如CA42型16V-22μF规格,被Ag后tgδ为1.98%,而工序标准只要求tgδ≤3.4%。代替进口银浆,已应用于生产中。     

柔性银包铜基导电线路的制备与性能

针对导电银浆价格高、导电铜浆易氧化等问题,采用银包铜粉作为导电填料,聚氨酯改性丙烯酸树脂为树脂基体,通过丝网印刷在聚酰亚胺薄膜上印制导电线路,并用热固化的方式进行固化,从而获得导电性能优良的柔性银包铜基导电线路。结果表明:当银包铜粉的含量为65%(质量分数)时,制备的导电胶各项性能达到最佳值,满足丝印要求,平均膜厚为29.25μm,固化后得到的导电膜电阻率达到最低值1.06×10~(-3)Ω·cm。     

低温共烧陶瓷内电极用导电银浆烧结匹配性能

采用优化后的玻璃粉配制成导电银浆,与MgSiO3-CaSiO3生瓷片共烧后形成导电厚膜,探讨了不同玻璃粉配方对所制厚膜的微观结构、热学性能、附着力、线膨胀系数和导电性能的影响,研究了导电银浆与基片低温共烧的匹配性能。结果表明,SiO2-Al2O3-B2O3-CaO-Li2O系玻璃粉配制的导电银浆低温共烧后获得的导电厚膜平滑、均匀、致密;随着该系玻璃粉中Li2O含量的增加,导电银浆的线胀系数逐渐降低;Li2O的质量分数为6%时,该浆料线胀系数最低,为18.482×10–6℃–1;Li2O的质量分数为2%时,导电厚膜与基片的线膨胀匹配性良好,导电性能最好,方阻为3.02 m?/□。     

导电胶导电/导热性能影响因素研究

选用双氰胺固化环氧树脂体系制备导电胶,分别研究了银粉含量和尺寸、低熔点合金以及短链二元酸的添加对导电胶导电/导热性能的影响。结果表明,所制导电胶的导电及导热性能均随银粉含量的增加或尺寸(3~9μm)的增大而增强。低熔点合金可在银粉间形成冶金键合,降低银粉间的接触电阻与热阻,从而有效提高导电胶的导电及导热性能。少量己二酸的添加可有效去除银粉表面的绝缘油酸,提高导电胶的导电性能,同时其会与双氰胺反应起到偶联作用,降低银粉与树脂的接触热阻,最终有效提高导电胶的导热性能。     

印制电路板铜导线断路修补方法的探索与应用

以相关化学知识中的“银镜反应”和“电镀铜”等理论依据为切入点,建立全新的化学印制电路板断路修补模式。经过多次实验和总结,提出了一套用导电银浆作为打底导电层,用电刷镀铜为覆盖层的印制电路板铜导线断路修补路径。为企业减少了废品损失,同时减少了印制电路板生产过程中产生的固体废弃物对环境的污染。     

Formulation and characterization of anisotropic conductive adhesive paste for microelectronics packaging applications

There has been a steadily increasing interest in using electrically conductive adhesives as interconnecting materials in electronics manufacturing. In this paper, several anisotropic conductive adhesive (ACA) pastes were formulated, which consist of diglycidyl ether of bisphenol F or diglycidyl ether of bisphenol A as polymer matrix, imidazoles as curing agents, and different sizes of silver (Ag) powders or gold (Au)-coated polymer spheres as conductive particles. The effects of ACA resin and different curing agents, as well as different conductive particles, on flexible substrate of the flip-chip joint were studied. The results show that the size and type of different conductive particles have very limited influence on an ACA flip-chip joint. The ACA resin as well as the curing agent can affect the reliability of the joint. The same results can be applied for the failure analysis of ACA flip-chip technology.     

银浆中的玻璃粉对晶硅太阳电池串联电阻的影响

研究了丝网印刷银电极中玻璃粉对晶体硅太阳能电池的串联电阻的影响。通过制备不同含量的玻璃粉银浆料,以及对浆料的体电阻率、接触电阻和焊接拉力等性能的表征测试,发现银粉颗粒间隙是造成银电极体电阻增大的主要因素,在一定范围内,用PbO-SiO2系玻璃粉有助于降低银电极体电阻和接触电阻,增加焊接拉力。     

片式电阻用有机聚合物电子浆料研制

通过选择与优化有机树脂、固化剂、溶剂、填料等,开发了片式电阻用的系列有机聚合物电子浆料。该系列浆料包括端涂银导体浆料、包封介质浆料、标志浆料。采用厚膜印刷工艺,200℃固化。浆料中铅含量小于1×10–4。端涂银导体浆料固化膜耐酸性好,附着力高;包封介质浆料固化膜层平整致密,且绝缘电阻≥104MΩ,击穿电压≥500 V;标志浆料细线分辨率好。     

Effects of Solvent Type on Low-Temperature Sintering of Silver Oxide Paste to Form Electrically Conductive Silver Film

Silver oxide pastes were formulated from silver oxide powder, silver α-neodecanoate, and solvents, which lowers the sintering temperature of printed silver films to 150°C. In this paper, solvent effects were investigated through the formulation of silver oxide pastes using various solvents with high boiling points such as glycol, ether, and terpineol. Solvent structures such as terminal methyl and alkoxyl groups affected the solubility of silver α-neodecanoate and the swelling of the polydimethylsiloxane (PDMS) blanket. Particularly, higher solubility induced uniform mixing of the silver oxide powder and silver α-neodecanoate, which resulted in higher conductivity after sintering. Glycols and monoalkyl ethers reacted with the silver oxide or silver salt, which deteriorated the pot life of the paste. Among the various candidates, α-terpineol satisfied all the requirements such as printability and stability, exhibiting a solubility of 47.8 g in 100 g of solvent, PDMS swelling of 4.6%, and conductivity of 1.8 × 10⁵ S/cm after sintering at 150°C for 30 min.     

An aqueous developable photoimageable silver conductor composition for high density electronic packaging

In our preliminary work, we have formulated aqueous developable photoimageable thick film conductor pastes, consisting of ‘inhouse processed’ submicron sized silver powders (functional material), micron sized lead borosilicate glass frits (permanent binder), epoxy acrylate resin with pendant –COOH group (base photoimageable polymer/temporary binder/organic vehicle) and 2,2′-dimethoxy-2-phenylacetophenone (photoinitiator). The conductor pastes thus formulated were manually screen printed on the alumina substrates, dried, exposed to the ultra-violet light through the desired test patterns, developed in a 1% aqueous sodium carbonate solution, and subjected to a standard one-hour thick film firing cycle. Solid content of the polymer appears to influence the paste performance. Prima facie observations indicate that the paste with the organic:inorganic ratio of 28:72 (corresponding to solid content of 89.9% of the polymer system) exhibits better electrical conductivity, relatively smooth surface finish and line/space resolution of 100 μm with ±5 μm accuracy. Investigations related to the effect of glass content on the properties of photoimageable conductor paste are also furnished in this communication.     

用纳米银棒和颗粒制备高导电性油墨

研制了一种高导电性油墨。首先,分别以乙二醇和N,N-二甲基甲酰胺为还原剂,还原硝酸银溶液得到纳米银棒和纳米银球形颗粒。用纳米银棒和纳米银球形颗粒混合银粉、双酚A环氧树脂/酚醛树脂、丁酮等其他助剂配制导电油墨。研究了不同固化温度、固化时间对所制油墨导电性能的影响。结果表明,在150℃固化20 min该油墨印刷的导电图形具有很致密的表面结构和丰富的三维导电网络,其体积电阻率达3.6 10–6.cm。     

导电石墨浆料的研制

通过选用不同性能的混合溶剂和分散剂,导电载体等组分,改进真空显示器用导电石墨浆料的性能。结果表明,当ζ(玻璃粉:导电载体)为1:1时,有机载体中w(乙基纤维素)为4%~8%,w(分散剂)为10%时,浆料各方面性能达到最佳,其中方阻为110?/□,硬度为12.5N/mm2。