Aromatic polyamides containing keto-benzocyclobutene pendants

A series of novel benzocyclobutene (BCB)-pendanted polyamides (inherent viscosities: 0.20–0.69 dL/g) was synthesized from 3,5-diaminophenyl-4-benzocyclobutenyl ketone, and terephthaloyl, isophthaloyl, 4,4′-oxydibenzoyl chlorides, as well as 4,4′-(o-phenylenedioxy)dibenzoyl chloride. The DSC studies demonstrated that the BCB crosslinking exothermic transition occurred at nearly the same temperature (max. ∼︁ 275°C) for all the four polyamides, and they were thermally stable up to 380°C in helium, where the weight loss started to occur. TGA and DSC studies in air indicated that the polymers, in contrast to the model compound, showed evidence of oxidation just prior to or occurring simultaneously with the BCB crosslinking reaction. This could be attributed to the oxidation of the reactive diene generated from the ring-opening of the BCB competing with the process of two BCB pendant units approaching each other for crosslinking reaction. Preliminary examination of the BCB-pendanted polyamide regenerated from a methanesulfonic acid solution indicates that the BCB ring is quite stable (DSC evidence) in the strong acid medium. © 1996 John Wiley & Sons, Inc.     

基于BCB的薄膜多层基板在毫米波T/R组件中的应用

基于BCB的薄膜多层基板具有优异的高频特性,是毫米波频段多芯片组件集成封装的重要途径。研究了BCB薄膜多层基板在Ka波段相控阵雷达T/R组件中应用的可行性,首先与LTCC基板对比验证了BCB微带线的传输特性,然后研制了功率分配/合成器、穿墙过渡等关键微波无源电路,最后设计了八通道的无源组件进行微波性能测试评估,结果表明基于BCB的薄膜多层基板能够满足应用需要。     

A Novel Electroless Process for Embedding a Thin Film Resistor on the Benzocyclobutene Dielectric

To realize embedded resistors on multilayer benzocyclobutene (BCB) either on-chip or on-board, a low-cost large format electroless process for deposition of NiP and NiWP thin-film resistors using both low-temperature (25°C) and high-temperature (90°C) baths has been developed. The electroless process exhibits uniform resistor thickness in the submicron range and offers low profile and excellent adhesion to the BCB dielectric layer. The resistor films also act as a seed layer for direct electroplating of copper traces. The NiP alloys can also be tailored to a variable temperature coefficient of resistance (TCR) with different alloy compositions. The electroless process can be adopted in the PCB manufacturing industries with no additional investment. This article is the first report on electroless plated thin film resistors on low loss BCB dielectric.     

利用非光敏BCB树脂实现多芯片组件平坦化研究

多层布线和绝缘介质材料的引入使得多芯片组件的芯片表面形貌凸凹不平,采用旋涂介质膜实现芯片表面平坦是常用的平坦化方法.分别介绍了聚酰亚胺、旋涂玻璃膜和苯并环丁烯(BCB)的平坦化特性,论述了非光敏BCB树脂的平坦化工艺原理.在此原理的基础上实现了非致冷红外焦平面的读出电路芯片平坦化,表面台阶从1.39 μm下降到0.097 μm,平坦度达到93%.     

布喇格反射型宽带单晶薄膜体声波滤波器

该文研究了一种新型布喇格反射型薄膜体声波(BAW)滤波器的设计方法与制备技术。BAW器件选择机电耦合系数较大的Y43°-铌酸锂(Y43°-LN)单晶薄膜作为压电层材料,并以苯并环丁烯(BCB)作为晶圆键合层,采用离子注入剥离法将亚微米厚度的Y43°-LN单晶薄膜转移至具有布喇格反射层的衬底。BCB既作为键合层,也作为布喇格反射层的第一低声阻抗层,实现了单晶BAW滤波器的制备。设计并制备了三阶BAW滤波器,中心频率为2.93 GHz,绝对带宽和分数带宽分别为247 MHz和8.4%。结果表明,采用薄膜转移技术制备的高机电耦合系数LN单晶薄膜能够实现大带宽BAW滤波器的制备。     

A wafer-level 3D packaging structure with Benzocyclobutene as a dielectric for multichip module fabrication

A new wafer-level 3D packaging structure with Benzocyclobutene (BCB) as interlayer dielectrics (ELDs) for multichip module fabrication is proposed for application in the Ku-band wave. The packaging structure consists of two layers of BCB films and three layers of metallized films, in which the monolithic microwave IC (MMIC), thin film resistors, striplines and microstrip lines are integrated. Wet etched cavities fabricated on the silicon substrate are used for mounting active and passive components. BCB layers cover the components and serve as ILDs for interconnections. Gold bumps are used as electric interconnections between different layers, which eliminates the need to prepare vias by costly dry etching and deposition processes. In order to get high-quality BCB films for the subsequent chemical mechanical planarization (CMP) and multilayer metallization processes, the BCB curing profile is optimized and the roughness of the BCB film after the CMP process is kept lower than 10 nm. The thermal, mechanical and electrical properties of the packaging structure are investigated. The thermal resistance can be controlled below 2 ℃/W. The average shear strength of the gold bumps on the BCB surface is around 70 N/mm~2. The performances of MMIC and interconnection structure at high frequencies are optimized and tested. The 5 -parameters curves of the packaged MMIC shift slightly showing perfect transmission character. The insertion loss change after the packaging process is less than 1 dB range at the operating frequency and the return loss is less than -8 dB from 10 to 15 GHz.     

X-ray diffraction investigation of perfluoro-4-methylenecyclohexa-2,5-dienones

Perfluorinated 8-phenyl-7,8-diethylbicyclo[4.2.0]octa-1,4,6-trien-3-one (3), 2-(4-oxocyclohexa-2,5-dienylidene)-1,1-diethylbenzocyclobutene (4) and 2-(4-oxocyclohexa-2,5-dienylidene)-5-(2-phenyl-cis-1,2-diethylbenzocyclobuten-1-yloxy)-1,1-diethylbenzocyclobutene (5), including the 4-methylencyclohexa-2,5-dienone fragment, were prepared by the reaction of perfluoro-1,1-(1) and-1,2-diethylbenzocyclobutene (2) with pentafluorobenzene in SbF₅. Single crystal X-ray diffraction study of compounds 3–5 revealed that the oxygen atom of the C=O group participated in the formation of supramolecular architectures in all three compounds, and C=O…π bonding may be considered as the corresponding synthon (with increased separation in the case of compound 5). C-F…π bonding acts as a second synthon. F…F interactions in crystals 3–5 were classified as stabilizing or enforced.     

采用BCB平整技术的高速850 nm垂直面发射激光器

垂直腔面发射激光器因其具有低阈值、低功耗、可实现高速调制等优势,广泛地应用于光通信和光互连等领域。寄生电容是影响激光器的调制带宽的主要因素之一。本文通过采用低k值的苯并环丁烯（BCB）平整技术有效地降低了垂直腔面发射激光器的寄生电容。详细研究了BCB平整技术的最优工艺参数,为未来高速垂直腔面发射激光器的制造技术提供参考。低k值BCB平整垂直腔面发射激光器在7 μm氧化孔径下3 dB小信号调制带宽可达15.2 GHz。     

Synthesis and characterization of siloxane resins derived from silphenylene‐siloxane copolymers bearing benzocyclobutene pendant groups

Two bis(dimethylamimo)silanes with benzocyclobutene (BCB) groups, bis(dimethylamino)methyl(4′‐benzocyclobutenyl)silane ( 2 ) and bis(dimethylamino)methyl [2′‐(4′‐benzocyclobutenyl)vinyl]silane ( 4 ), were synthesized from different synthetic routes, which were then employed to prepare two novel silphenylene‐siloxane copolymers (SiBu and SiViBu) bearing latent reactive BCB groups by polycondensation procedure with 1,4‐bis(hydroxydimethylsilyl)benzene. At elevated temperatures these copolymers were readily converted to highly crosslinked films and molding disks with network structures by polymer chain crosslinking, which followed the first‐order kinetic reaction model. The final resins of SiBu and SiViBu demonstrated excellent thermal stability with high glass transition temperatures (218 and 256 °C) and high temperatures at 5% weight loss (553 and 526 °C in N₂, 530 and 508 °C in air). After aging at 300 °C in air for 100 h, the cured resins showed weight loss lower than 4%. The films of cured SiBu and SiViBu also exhibited relatively low dielectric constants of 2.66 and 2.64, low dissipation factors of 2.23 and 2.12 × 10^?3, low water absorptions (≤0.28%), and high transparence in the visible region with cutoff wavelengths of 321 and 314 nm. Moreover, the aged films exhibited good dielectric properties and low water absorptions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7868–7881, 2008     

RhI‐Catalyzed Benzo/[7+1] Cycloaddition of Cyclopropyl‐Benzocyclobutenes and CO by Merging Thermal and Metal‐Catalyzed CC Bond Cleavages

A Rh‐catalyzed benzo/[7+1] cycloaddition of cyclopropyl‐benzocyclobutenes (CP‐BCBs) and CO to benzocyclooctenones has been developed. In this reaction, CP‐BCB acts as a benzo/7‐C synthon and the reaction involves two C?C bond cleavages: a thermal electrocyclic ring‐opening of the four‐membered ring in CP‐BCB and a Rh‐catalyzed C?C cleavage of the cyclopropane ring.