This work tests the effect on microstructure, flexural strength, flexural moduli, plus the electrical and thermal conductivity of carbon/carbon composites with Mesocarbon Microbeads (MCMBs) content ranging 0 -30% by weight during carbonization. These composites were reinforced by oxidative PAN Base fiber felts, and matrix precursor was resol-type-phenolic resin. MCMBs with a weight fraction of 0 -30% were added to the matrix to elucidate the effect. Liquid-phase impregnation was applied to reinforce matrix carbon. Cured composites were stabilized at 230°C, then heat-treated at 400, 600, 800, 900 and 1000°C for carbonization. The measured flexural strength after heattreated at 1000°C was 51.20, 49.59, 43.55, and 38.76 MPa for MCMBs with 0, 10, 20, and 30% added to composites; mean flexural moduli were l.73, 1.24, 0.73, and 0.57 MPa, respectively. Adding MCMBs reduced both strength and modulus because of cracks and avoids caused by different shrinkage between resin and MCMBs; adding 30 wt % MCMBs raised thermal conductivity of C/C composites from 1.55 to 1.78 W/mK and reduced electric resistivity from 1.8 ϫ 10 Ϫ2 to 5.97 ϫ 10 Ϫ3 ⍀ cm.
Self-assembled monolayers (SAMs) are extensively used in microelectronic copper metallization primarily as seed-trapping layers, diffusion barriers, or pore-sealants for porous dielectric materials. However, direct electroless copper plating of nitride barrier layers assisted by a seed-trapping SAM is rarely examined. Therefore, this work uses TaN, a standard barrier material for Cu metallization, as a model substrate to develop a new seeding (catalyst formation) process for electroless copper plating, involving substrate pretreatments from piranha etching (hydroxylation), octadecyltrichlorosilane SAM (OTS-SAM) deposition and subsequent functionalization. Catalytic particles upon adsorption onto piranha-treated (reference) TaN layers via Ta−OH linkages tend to agglomerate to give a limited density of 8 × 1013 m−2. In contrast, those adsorbed on piranha-treated TaN layers with a plasma-functionalized OTS-SAM over-coating are free from agglomeration and remain an average size of only 3 nm, along with an elevated density of 1 × 1015 m−2. X-ray photoelectron spectroscopy, together with transmission electron microscopy, clearly identifies the thin-film materials deposited and functional groups induced by each of the pretreatments, allowing the mechanism of seeding enhancement to be clarified. Finally, the enhancement of seeding to benefit electroless copper plating will be demonstrated.
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