【作者】 谭麟；

【导师】 赵建青；

【作者基本信息】 华南理工大学 ， 材料学， 2010， 博士

【摘要】 随着电子信息技术特别是大规模集成电路的突飞猛进,电子产品正朝着轻量薄形化、高性能化和多功能化方向发展,其对介质材料的要求越来越高。迫切需要开发新一代低介电常数材料。聚酰亚胺（PI）作为一种高性能聚合物材料,从上世纪70年代起已被用作电路板金属层间介质。PI具有优良的耐热性,较高的力学性能、耐化学腐蚀性和粘结性等,被广泛应用于微电子领域。PI本征介电常数值介于2.9³.4之间,已不能满足电子工业对新一代介电质材料的要求。目前主要通过在PI主链中引入氟元素以及在PI中掺杂介孔材料来降低PI的介电常数。本论文通过对三种不同结构含纳米孔洞的多金属氧酸盐（POMs）进行有机改性,并将改性物引入对苯二酐（PMDA）-二苯醚二胺（ODA）型PI及含氟共聚型PI中,制备了一系列PI/POMs复合薄膜。通过红外光谱、核磁共振谱、X-射线表面光电子能谱、X-射线衍射、透射电镜、扫描电镜、凝胶色谱、动态粘弹分析仪、差热扫描量热和热重分析等对其结构和性能进行了详细研究。1.以带氨基官能团的硅烷偶联剂3-氨丙基三乙氧基硅烷（KH550）对Keggin结构POMsK₈SiW₁₁O₃₉(SiW₁₁)进行表面有机改性,制备了有机改性物SiW₁₁KH550。分别将SiW₁₁和SiW₁₁KH550通过前驱体溶液共混法引入PMDA-ODA型聚酰胺酸（PAA）中,两步法制备了一系列PI复合薄膜。粘度及红外测试表明,SiW₁₁KH550通过氨基官能团与PAA末端酐基官能团反应共聚入PI主链中。XRD及SEM测试结果显示,SiW₁₁在PI中形成2μm的结晶团聚物;SiW₁₁KH550则均匀分散在聚合物中,其大小约为20⁵0nm之间。在0wt%¹0wt%的SiW₁₁KH550添加量范围内,随SiW₁₁KH550添加量的增加,复合薄膜的玻璃化温度、热分解温度有所提高,而介电常数则降低至2.10。相反,添加SiW₁₁使聚合物的物化性能变差。2. SiW₁₁KH550添加量受PAA末端酐基的限制。为进一步增大SiW₁₁的添加量,以带环氧基官能团的硅烷偶联剂3-缩水甘油醚氧丙基三甲氧基硅烷（KH560）对SiW₁₁进行有机改性,使SiW₁₁表面带有环氧官能团。红外谱图分析发现带环氧官能团的SiW₁₁不但能与PAA末端酐基反应,而且能与PAA主链上羟基官能团形成氢键作用,有利于SiW₁₁的分散。在0wt%²0wt%的SiW₁₁KH560添加量范围内,复合薄膜的介电常数随SiW₁₁KH560添加量的增大从3.29降低至2.81。3.相比于共聚法将SiW₁₁引入PI,共混法添加过程简单,影响因素单一。基于此,以带双键的硅烷偶联剂乙烯基三甲氧基硅烷（A171）对SiW₁₁进行有机改性,制得有机改性物SiW₁₁A171,以增大SiW₁₁与PI的相容性。XRD及SEM测试显示,SiW₁₁A171均匀分散于PI薄膜中,所特有的结晶峰也随之消失,与聚合物基体的相容性大为改善。在0wt%²0wt%的SiW₁₁A171添加量范围内,制备的复合薄膜的介电常数低至2.05。4.用KH550、A171改性了不同结构的POMs—K₇PW₁₁O₃₉(PW₁₁ Keggin结构)和K₆P₂W₁₇O₆₁(P₂W₁₇ Dawson结构),并将上述改性物引入PMDA-ODA型PI中制备了一系列PI复合薄膜。结果表明复合薄膜的介电常数受POMs组成、结构及POMs离子电负性等因素的影响。其中,PW系列的POMs降低复合薄膜介电常数的效果好于SiW系列的POMs;Dawson结构POMs好于Keggin结构POMs;电负性越大,POMs降低复合薄膜介电常数的效率越高。所制备的一系列复合薄膜中,介电常数最低值出现在添加量为20wt%时的氨基改性P₂W₁₇的复合薄膜,其介电常数为1.68。5.以PMDA、ODA、六氟二酐（6FDA）和2,2’-二（三氟甲基）联苯二胺（TFDB）为单体合成了含氟嵌段共聚型PI。通过溶解性能、成膜性能等研究发现,当含氟组分摩尔比占共聚物的50%时,所制备的共聚薄膜具有较好的综合性能。其介电常数为2.84。运用Maxwell方程、Lorenz介电理论以及Vogel介电理论对所制备的共聚物进行介电常数计算发现,后两种理论计算得出的介电常数与实测值具有很好的吻合关系,其最大误差小于10%。将P₂W₁₇KH550添加入含氟共聚PI中,当添加量为15wt%时,制备的复合薄膜介电常数为1.63,同时所制备的复合薄膜能溶解于极性惰性溶剂DMF、DMAc等。更多还原

【Abstract】 With the rapid development of electronic communication technology, especially the development of Ultra Large Scale Integrated Circuit, electronic products become more and more portable and functional, the requirement for materials with low dielectric constant increased。It is very crucial to develop next generation dielectrics. Polyimides, as high profermance polymer materials, were used as electronic medium between metal layers from 1970s. Polyimides exhibited good thermal stability, mechnical property, chemical-resistants and felting property, were widely applicated in microelectronic. The dielectric constant for ordinary polyimides were in the range of 2.9³.4, which can not meet the requirement for new dielectrics. Several methods are intoduced in order to decrease the dielectric constant of polyimides, such as incorporation of fluorinated substituent intoPIs; introduction of voids into PIs by foaming processes andembedment of nanoporous inorganic/organic hybrids like POSS into PIs. In this paper, three polyoxometalates（POMs） with different structures were firsr modification by silane coupling agents, and then those inorganic hybirds were incorporated in to polyimide（PMDA-ODA） and fluoride polyimide to fabrication series of polyimides/polyoxometalate composites thin films. FTIR, NMR, TEM, SEM, XRD, XPS, DMA, TGA and DSC were used to characterize the structures and properties of the composites.1. A mono-lancunary keggin-type decatungstosilicate (SiW₁₁) polyoxometalate modified byγ-aminopropyltriethoxysilane （KH550） was incorporated into polyimide （PI） through copolymerization. Nuclear magnetic resonance （NMR）, Fourier transition infrared spectroscopy （FTIR） and wide angle X-ray diffraction （WAXD） were used to characterize the structure and composition of the polyoxometalate-organosilane hybrid (SiW₁₁KH550) and PI/SiW₁₁KH550 copolymers. The differential scanning calorimetry （DSC） studies indicate that the glass transition temperature （Tg） of PI/SiW₁₁KH550 copolymers increase from 337°C （for neat PI） to 364°C (for the copolymer sample with 10 wt% of SiW₁₁KH550). Dielectric measurement showed that the dielectric constant for copolymer thin films decreased with the increasing SiW₁₁KH550 content, and the dielectric constant is 2.10 for the copolymer sample with 10wt% of SiW₁₁KH550. On the contrary, incorporation SiW₁₁ into polyimide matrix dicreased the porperties of PI mentioned before.2. A silane-modified mono-lacunary Keggin-type polyoxometalate SiW₁₁KH560, was obtained by reaction of （3-Glycidoxypropyl）trimethoxy silane（KH560） with K8SiW₁₁O₃₉(SiW₁₁). FTIR and XPS spectrums demonstrate that KH560 is grafted onto the polyoxometalate. Then the modified polyoxometalate was added into PMDA -ODA poly（amic acid） solution, and the poly（amic acid） solution were thermally imidized to form polyimide/polyoxometalate composites. FTIR results showed that SiW₁₁KH560 can copolymerize into PI matrix and It also hydrogen bongding to PI matrix. The EDS （W-mapping） studies on the composite films reveal that the polyoxometalate clusters are well dispersed in the polyimide matrix. The incoporation of SiW₁₁KH560 into polyimide reduced the dielectric constant of the latter from 3.29 to 2.81.3. A silane-modified mono-lacunary Keggin-type polyoxometalate SiW₁₁A171, was obtained by reaction of vinyltrimethoxysilane with K8(SiW₁₁O₃₉). Then the modified polyoxometalate was physically blended with the PMDA-ODA poly（amic acid） and the blends were thermally imidized to form polyimide/polyoxometalate composites. The x-ray diffraction （XRD） analysis indicates that the polyoxometalate clusters can not form crystalline structure in the composite, suggesting that the blending lead to improved compatibility between the polymer matrix and the modified polyoxometalate. The EDS （W-mapping） studies on the composite films reveal that the polyoxometalate clusters are well dispersed in the polyimide matrix. The physical incoporation of modified SiW₁₁A171 into polyimide remarkably reduced the dielectric constant of the latter from 3.29 to 2.05 when 20 wt % of SiW₁₁A171 was used.4. PW₁₁ and P₂W₁₇ with different structures were modification by KH550 and A171, and then incorporated into PMDA-ODA PI to fubrication polyimide composites respectively. Dielectric measurement shows that dielectric constant of composites is affact by the components and structure of polyoxometalates. Experientially, PW series polyoxometalates are more effectively than SiW series ones to decrease the dielectric constant of polyimide. Furthermore, Dowson type polyoxometalates are more effectively than keggin types, and the more electronegative the POMs are, the more effective it can to decrease the dielectric constant of composites.5. Fluoride polyimide copolymers were synthesis using PMDA, ODA, 6FDA, TFDB as monomers. Dissolving testing and films fabrication process monitoring results show that fluoride polyimide has excellent properties when the fluoride PI contained 50mol% fluorine monomers. Maxwell equation, Lorenz and Vogel theories were used to calculate the dielectric constant of those copolymers, the results show that Lorenz and Vogel theories are suitable for this copolymer system. After that, P₂W₁₇KH550 were incorporated into the copolymer, the dielectric constant of those composites are decreased to 1.63 when 15wt% of P₂W₁₇KH550 was used, meanwhile, those composites can be dissolved into DMF, DMAc and NMP.更多还原