Remote plasma enhanced cyclic etching of a cyclosiloxane polymer thin film

The continuous evolution of chip manufacturing demands the development of materials with ultra-low dielectric constants.With advantageous dielectric and mechanical properties,initiated chemical vapor deposited(iCVD)poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane)(pV3D3)emerges as a promising candidate.However,previous works have not explored etching for this cyclosiloxane polymer thin film,which is indispensable for potential applications to the back-end-of-line fabrication.Here,we developed an etching process utilizing O2/Ar remote plasma for cyclic removal of iCVD pV3D3 thin film at sub-nanometer scale.We employed in-situ quartz crystal microbalance to investigate the process parameters including the plasma power,plasma duration and O2 flow rate.X-ray photoelectron spectroscopy and cross-sectional microscopy reveal the formation of an oxidized skin layer during the etching process.This skin layer further substantiates an etching mechanism driven by surface oxidation and sputtering.Additionally,this oxidized skin layer leads to improved elastic modulus and hardness and acts as a barrier layer for protecting the bottom cyclosiloxane polymer from further oxidation.

DHA induces adipocyte lipolysis through endoplasmic reticulum stress and the cAMP/PKA signaling pathway in grass carp(Ctenopharyngodon idella)

Docosahexaenoic acid(DHA)is a biologically active fatty acid that reduces the accumulation of lipids.However,the molecular mechanism underlying this process,particularly in fish,is not well understood.Recent studies show that endoplasmic reticulum(ER)stress triggers the activation of the unfolded protein response,which has been revealed to play an essential role in lipid metabolism.In this study,we explored the effect of DHA on ER stress and investigated the potential molecular mechanisms underlying DHA-induced adipocyte lipolysis in grass carp(Ctenopharyngodon idella)both in vivo and in vitro.We found that DHA remarkably reduced the triglyceride content,increased the secretion of glycerol,pro-moted lipolysis in adipocytes and evoked ER stress,whereas inhibiting ER stress using 4-phenyl butyric acid(4-PBA)inhibited the effects of DHA(P<0.05).These results implied that ER stress potentially participates in DHA-induced adipocyte lipolysis.Additionally,STF-083010,a specific inositol-requiring enzyme 1a(IRE1a)-inhibitor,attenuated the effects of DHA on lipolysis,demonstrating that IRE1a and X-box binding protein 1 potentially participate in DHA-induced lipolysis.DHA also activated the cyclic adenosine monophosphate(cAMP)-dependent protein kinase A(PKA)pathway by increasing the level of cAMP and activating the PKA enzyme(P<0.05).Nevertheless,H89,a PKA inhibitor,weakened DHA-induced lipolysis by inhibiting the cAMP/PKA signaling pathway.Furthermore,inhibiting ER stress us-ing 4-PBA also inhibited lipolysis and alleviated DHA-induced activation of the cAMP/PKA signaling pathway,suggesting that ER stress may participate in DHA-induced lipolysis through the activation of the cAMP/PKA signaling pathway.Our data illustrate that DHA supplementation can be a promising nutritional strategy for ameliorating lipid accumulation in grass carp.The present study elucidated the molecular mechanism for DHA-induced lipolysis in grass carp adipocytes and emphasized the impor-tance of ER stress and the cAMP/PKA pathway in DHA-induced lipolysis.These results deepen our un-derstanding of ameliorating lipids deposition in freshwater fish by targeting DHA.