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本文介绍一种新型的用于石英晶体的单组份导电胶。分析了导电机理和配方选择,介绍了这种胶的测试数据。这种胶用于石英晶体的性能:电阻率5.2×10~(-4)(欧姆—厘米);粘结强度高,能经受高温(+125℃)、低温(-50℃)循环冲击;低温不龟裂;在晶体上使用不流失、不扩散、不拉丝、不腐蚀污染晶体;胶合后对石英谐振器的频率、电阻——温度特性没有不良影响;胶合后对频率、等效电阻影响小,结果满意。一次配成的胶液存放一年以上仍能继续使用,固化后的导电胶,长期存放,电阻保持不变。 相似文献
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针对导电胶变色的现象,分析了变色导电胶的外观、微观结构及成分,研究了导电胶变色现象对接触电阻的影响。找出了导电胶变色的原因,导电胶固化后裸露在环氧树脂表面的银粒子被硫化生成黑色的硫化银所致,且随着硫化银的增多颜色由浅变深。试验结果表明导电胶变色现象对接触电阻无影响。 相似文献
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本文讲述了微组装中粘接技术需采用性能良好的导电胶,从粘接理论入手,结合实施结果和实践经验,详细论述了如何选择适当的导电胶,并具体分析了粘接工艺中胶层厚度,固化温度、时间、压力及粘接表面对粘接强度,导电性、导热性和可靠性等的影响。 相似文献
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导电胶作为元铅连接材料的一种,近年来在微电子封装、组装中越来越受重视。本文简单介绍了导电胶的分类、组成,重点介绍一种新的导电胶电阻的测试方法和导电胶在固化过程中电阻的自动测量采集系统设计,通过最后选用的导电胶实验证明本文设计的系统完全能够满足导电胶电阻的测试要求。 相似文献
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微波芯片元件的导电胶粘接工艺与应用 总被引:1,自引:0,他引:1
导电胶常用于微波组件的组装过程,其粘接强度、导电、导热和韧性等性能指标严重影响其应用范围.分析了导电胶的国内外情况和主要性能参数,总结了混合微电路对导电胶应用的指标要求.通过微波芯片元件粘接工艺过程,分析了导电胶的固化工艺与粘接强度和玻璃化转变温度的关系、胶层厚度与热阻的关系、胶点位置和大小与粘片位置控制等方面的影响关系.测试结果显示,经导电胶粘接的芯片元件的电性能和粘接强度等指标均满足设计和使用要求,产品具有较好的可靠性和一致性. 相似文献
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各向异性导电胶粘接可靠性研究进展 总被引:12,自引:0,他引:12
介绍各向异性导电胶导电机理和粘接工艺,以及影响它的粘接可靠性因素和最佳参数的研究,如粘接温度、固化时间、粘接压力、粒子含量等。对各向异性导电胶粘接可靠性中的开路、短路、接触电阻与粘接压力和温度循环的关系进行了讨论,并介绍了各向异性导电胶可靠性的理论计算模型。 相似文献
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Study on the Effects of Adipic Acid on Properties
of Dicyandiamide-Cured Electrically Conductive Adhesive
and the Interaction Mechanism 总被引:1,自引:0,他引:1
Ling Wang Chao Wan Yonggao Fu Hongtao Chen Xiaojian Liu Mingyu Li 《Journal of Electronic Materials》2014,43(1):132-136
A small quantity of adipic acid was found to improve the performance of dicyandiamide-cured electrically conductive adhesive (ECA) by enhancing its electrical conductivity and mechanical properties. The mechanism of action of the adipic acid and its effects on the ECA were examined. The results indicated that adipic acid replaced the electrically insulating lubricant on the surface of the silver flakes, which significantly improved the electrical conductivity. Specifically, one of the acidic functional groups in adipic acid reacted with the silver flakes, and an amidation reaction occurred between the other acidic functional group in adipic acid and the dicyandiamide, which participated in the curing reaction. Therefore, adipic acid may act as a coupling agent to improve the overall ECA performance. 相似文献
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Anisotropic conductive adhesive film (ACF) can be preheated by microwave (MW) radiation in order to reduce the bonding time
for flip-chip technology. Due to sluggish and nonuniform curing kinetics at the beginning of the curing reaction, thermal
curing of epoxy is more time consuming. Therefore, MW radiation may be more effective, due to its uniform heating rate during
the cycle. In this paper, MW preheating (for 1–4 sec) of ACF prior to final bonding has been applied to determine the electrical
and mechanical performance of the bond. Powers of 80 and 240 W MW were used to study the effect of the MW preheating. A final
bonding time of 6–7 sec can be used for flip chip on flex bonding instead of 10–15 sec (standard time for flip chip bonding)
for MW preheating time and power used in this study. The contact resistance (as low as 0.01) is low in these samples, whereas
the standard resistance is 0.017 ohm (bonded at 180°C for 10 sec without prior MW preheating). The shear forces at breakage
were satisfactory (0.167–0.183 KN) for the samples bonded for 6–7 sec with MW preheating. This is very close and even higher
than the standard sample (0.173 KN). For MW preheating power of 80 W and sweeping time of 2 sec, final bonding at 6 sec can
also be used because of its low contact resistance (0.019 ohm). Scanning electron microscope (SEM) investigation of microjoints
and fracture surface shows uneven distribution of conductive particles and thick bond lines in samples bonded for 5 sec (with
MW preheating). Samples treated with MW radiation (80 W and 2–3 sec time) serve as evidence that well-distributed particles
along with thin bond lines cause low contact resistance and high joint strength. 相似文献
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Ying Fu Wang T. Johan Liu 《Components and Packaging Technologies, IEEE Transactions on》2003,26(1):193-198
Microwave heating significantly speeds up the curing process of polymer and polymer-based composites. The present theoretical work studies the microwave transmission through the electrically conductive adhesive (ECA), heat generation and transfer inside the ECA and subsequently the microwave heating rate of the ECA. By studying the temporal transmission property of the microwaves in the ECA, we have calculated quantitatively the electromagnetic field distribution around a metal filler. It has been shown that the penetration depth of the skin effect in the metal filler is significantly smaller than the one of a bulk metal material. The heat generation (microwave power absorption) is negligible in the metal filler due to its large electric conductivity. Furthermore, due to the high thermal conductivity, the thermal equilibrium between the metal filler and the surrounding adhesive is reached within a nano second (10/sup -9/ s). The temperature of the whole ECA system becomes uniform within a time interval of 10/sup -3/ s. When the temperature of the system is relatively low, the heating rate of the system is linearly proportional to the external microwave input power and the heating time. It gradually saturates when the temperature of the ECA is so high that the heat radiation from the ECA becomes significant. Numerical results of our theoretical model agree well with experimental data, thus providing a solid platform for designing the microwave curing process of the ECA. 相似文献
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Electrically conductive adhesive (ECA) is an alternative for the toxic lead-based solders. However, unstable electrical conductivity
has long been a haunting problem. Galvanic corrosion at the ECA/pad interface has recently been found to be the major mechanism
for this decay. Applying a more active metal or alloy on a dissimilar metal couple in contact can prohibit galvanic corrosion.
In this study, powders of aluminum, magnesium, zinc, and two aluminum alloys were added in an ECA and applied on five pad
surfaces. The aging of the bulk resistivity and contact resistance of the ECA/metal surface pairs were studied. The two alloys
significantly suppressed the increase of the contact resistance on all tested metal surfaces. 相似文献
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对SiC粉体进行热处理,采用Y2O3-MgO-Al2O3烧结助剂,在1 750~1 950℃下30 MPa热压烧结1 h,制备SiC陶瓷。TG分析SiC的氧化特性,测定Zeta-电位研究SiC粉体的分散特性,测定其高温浸润性研究烧结助剂与SiC之间的亲和性。结果表明:SiC粉体热处理和提高SiC浆体的pH值,有利于提高Zeta-电位,进而提高分散均匀性;Y2O3-MgO-Al2O3烧结助剂高温下与SiC具有良好的浸润性;SiC粉体热处理明显降低了烧结温度。尽管Y2O3-MgO-Al2O3烧结助剂在高温下有一定的挥发,但是当其含量大于等于9%(质量分数)时,1 800~1 950℃下热压烧结可获得显气孔率小于等于0.19%的致密SiC陶瓷,其热导率大于190 W.m–1.K–1。 相似文献
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A microwave (MW) preheating mechanism of anisotropic conductive adhesive film (ACF) has been introduced in order to reduce the bonding temperature for flip chip technology. Thermal curing of epoxy shows a very sluggish and non-uniform curing kinetics at the beginning of the curing reaction, but the rate increases with time and hence requires higher temperature. On the other hand MW radiation has the advantage of uniform heating rate during the cycle. In view of this, MW preheating (for 2/3 s) of ACF prior to final bonding has been applied to examine the electrical and mechanical performance of the bond. Low MW power has been used (80 and 240 W) to study the effect of the MW preheating. It has been found that 170 °C can be used for flip chip bonding instead of 180 °C (standard temperature for flip chip bonding) for MW preheating time and power used in this study. The contact resistance (0.015–0.025 Ω) is low in these samples where the standard resistance is 0.017 Ω (bonded at 180 °C without prior MW preheating). The shear forces at breakage were satisfactory (152–176 N) for the samples bonded at 170 °C with MW preheating, which is very close and even higher than the standard sample (173.3 N). For MW preheating time of 2 s, final bonding at 160 °C can also be used because of its low contact resistance (0.022–0.032 Ω), but the bond strength (137.3–145 N) is somewhat inferior to the standard one. 相似文献
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Enhancement of Electrical Properties of Electrically Conductive Adhesives (ECAs) by Using Novel Aldehydes 总被引:1,自引:0,他引:1
Li Y. Moon K.-S. Whitman A. Wong C. P. 《Components and Packaging Technologies, IEEE Transactions on》2006,29(4):758-763
To improve the electrical properties of electrically conductive adhesives (ECAs), different types of aldehydes, salicylaldehyde and transcinnamaldehyde, were introduced into ECA formulations. During the curing process, the aldehydes acted as a reducing agent and reduced metal oxide in ECAs. At the same time, aldehydes could consume ambient oxygen and prevent the oxidation of the metal fillers in the ECA. The oxidation product of aldehydes, carboxylic acids with shorter molecular chains, could partially replace or remove the long chain stearic acid (C 18) surfactant on the lubricated Ag flakes and enhance the electrons tunneling between the Ag flakes in the ECAs. As such, the multiple effects of aldehydes in ECAs improved the conductivity significantly. Dynamic mechanical analysis and thermomechanical analysis studies indicated the improved performance for mechanical and physical properties of ECAs as well 相似文献
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Non-conductive adhesive (NCA) flip-chip interconnects are emerging as an attractive alternative to lead or lead-free solder
interconnects due to their environmental friendliness, lower processing temperatures, and extendability to fine-pitch applications.
The electrical connectivity of an NCA interconnect relies solely on the pure mechanical contact between the integrated circuit
(IC) bump and the substrate pad; the electrical conductivity of the contact depends on the mechanical contact pressure, which
in turns depends to a large extent on the cure shrinkage characteristics of the NCA. Therefore, it is necessary to monitor
the evolution of the electrical conductivity which could reflect the impact of cure- and thermal-induced stresses during the
curing and cooling process, respectively. In this article, in situ measurement of the development of contact resistance during the bonding process of test chips was developed by using a mechanical
tester combined with a four-wire resistance measurement system. A drop of resistance induced by the cure stress during the
bonding process is clearly observed. With decreasing bonding temperature, the drop of contact resistance induced by cure shrinkage
becomes larger, while the cooling-induced drop of resistance becomes smaller. The evolution of contact resistance agrees well
with experimental observations of cure stress build-up. It is found that vitrification transformation during the curing of
the adhesive could lead to a large cure stress and result in the reduction of the␣contact resistance. Furthermore, no obvious
changes were observed when the applied load was removed at the end of bonding. 相似文献
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Ohmic heating was demonstrated as a novel curing method (or curing enhancement) useful in decreasing the resistivity of conductive traces printed with both micro- and nanoparticle-loaded inks while (1) only locally heating the substrate and (2) curing in a matter of seconds compared with the range of 30?min to 1?h required by traditional oven-curing. In one experiment using traces composed of microparticle ink, which required initial air-drying as a preprocess step, application of an ohmic curing cycle resulted in resistivity of 80?n???m, roughly six times that of bulk silver. In a second experiment employing nanoparticle inks, which required an initial thermal cure as a preprocess, a resistivity of 43?n???m, roughly three times that of bulk silver, was attained after the application of an ohmic curing cycle. Electrical characterization of the ohmic curing process was performed in real time to understand the impact of cycling and duration on the resulting conductivity. Finally, the effect of printed trace length on the ohmic curing process was explored and found to have a near-linear relationship with the reduction in resistance when the applied electrical current was normalized to measured resistance. The microstructural changes which occurred as a result of ohmic curing such as particle sintering and grain growth were characterized by scanning electron microscopy. The results presented in this work demonstrate the use of ohmic heating to overcome temperature limitations imposed on a thermal curing process by substrate material properties or other sources. 相似文献