With the introduction of EUV lithography,the photolithographic process in 5 nm logic process can be simplified to use mostly single exposure method.In a typical 5 nm logic process,the contact-poly pitch(CPP)is 44-50 n...With the introduction of EUV lithography,the photolithographic process in 5 nm logic process can be simplified to use mostly single exposure method.In a typical 5 nm logic process,the contact-poly pitch(CPP)is 44-50 nm,the minimum metal pitch(MPP)is around 30-32 nm.And the overlay budget is estimated to be 2.5 nm(on product overlay).Although the optical resolution of a 0.33NA exposure tool(such as ASML NXE3400)can reach below 32 nm pitch,stochastics in the EUV absorption in photoresists has limited its application to smaller pitches.For the CPP mentioned above,one can use 193 nm immersion lithography with Self-Aligned Double Patterning(SADP)technique to provide good image contrast(or CDU,LWR)as well as good overlay,as for the 10 and 7 nm generations.In the BEOL,however,the 30-32 pitch cannot be realized by a single EUV exposure with enough printing defect process window.If this pitch is to be done by 193 nm immersion lithography,more than 6-8 exposures are needed with very complicated overlay result.For EUV,this can be done through self-aligned LELE with both good CD and overlay control.We have done an optimization of the photolithographic process parameters for the typical metal with a self-developed aerial image simulator based on rigorous coupled wave analysis(RCWA)algorithm and the Abbe imaging routine with an EUV absorption model which describes stochastics.We have calibrated our model with wafer exposure data from several photoresists under collaboration with IMEC.As we have presented last year,to accommodate all pitches under a logic design rule,as well as to provide enough CDU for the logic device performance,in DUV lithography,a typical minimum exposure latitude(EL)for the poly and metal layers can be set at,respectively,18%and 13%.In EUV,due to the existence of stochastics,13%EL,which corresponds to an imaging contrast of 40%,seems not enough for the metal trenches,and to obtain an imaging contrast close to 100%,which yields an EL of 31.4%means that we need to relax minimum pitch to above 41 nm(conventional imaging limit for 0.33NA).This is the best imaging contrast a photolithographic process can provide to reduce LWR and stochastics.In EUV,due to the significantly smaller numerical apertures compared to DUV,the aberration impact can cause much more pronounced image registration error,in order to satisfy 2.5 nm total overlay,the aberration induced shift needs to be kept under 0.2 nm.We have also studied shadowing effect and mask 3D scattering effect and our results will be provided for discussion.展开更多
A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liq...A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liquor, the precipitation rate of vanadium in Bayer liquor is more than 85%.The vanadium-bearing precipitation is leached by NaHCO3 solution.The leaching rate of vanadium can reach 85% in the conditions of 95℃, 40 g·L-1 of NaHCO3 concentration, and ventilating of CO2.The 201 × 7 type of resin has good adsorption effect on vanadium in the leaching solution.The adsorption rate is more than 94% with the flow rate of 0.09 mL·min-1·g-1 of leaching solution and the temperature of 40-50℃.By using 3 mol·L-1 of NaOH to desorb the saturated resin after adsorption at 40-50℃, a solution with more than 5 g·L-1 of V2O5 can be obtained.After roasting ammonium metavanadate that precipitates from the desorption solution when NH4Cl is added at the temperature of 500-550℃ for 2 h, V2O5 with more than 99% of purity is obtained.展开更多
1 Introduction Tibet has nurmerous salt lakes.Laguocuo is one of the salt lakes,which is located to the sorthern of Ali Plateau,31°59′02″N-32°04′08″N,84°02′03″E-84°12′03″E.Its lake water is...1 Introduction Tibet has nurmerous salt lakes.Laguocuo is one of the salt lakes,which is located to the sorthern of Ali Plateau,31°59′02″N-32°04′08″N,84°02′03″E-84°12′03″E.Its lake water is rich in potassium,magnesium,lithium,boron,rubidium,cesium and other resources.The study of展开更多
Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN ge...Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN generated the corresponding acyl radicals, which were found to proceed in 5 exo trig or 6 endo trig cyclisations to afford high yields of cyclopentanones and cyclohexanones, The substitution groups on the substrates have played an important role on the regioselectivity of cyclisations.展开更多
In this paper, the features and possible causes of sea surface temperature(SST) biases over the Northwest Pacific are investigated based on a mixed-layer heat budget analysis in 21 coupled general circulation models(C...In this paper, the features and possible causes of sea surface temperature(SST) biases over the Northwest Pacific are investigated based on a mixed-layer heat budget analysis in 21 coupled general circulation models(CGCMs) from phase 5 of the Coupled Model Inter-comparison Project(CMIP5). Most CMIP5 models show cold SST biases throughout the year over the Northwest Pacific. The largest biases appear during summer, and the smallest biases occur during winter. These cold SST biases are seen at the basin scale and are mainly located in the inner region of the low and mid-latitudes. According to the mixed-layer heat budget analysis, overestimation of upward net sea surface heat fluxes associated with atmospheric processes are primarily responsible for the cold SST biases. Among the different components of surface heat fluxes, overestimated upward latent heat fluxes induced by the excessively strong surface winds contribute the most to the cold SST biases during the spring, autumn, and winter seasons. Conversely, during the summer, overestimated upward latent heat fluxes and underestimated downward solar radiations at the sea surface are equally important. Further analysis suggests that the overly strong surface winds over the Northwest Pacific during winter and spring are associated with excessive precipitation over the Maritime Continent region,whereas those occurring during summer and autumn are associated with the excessive northward extension of the intertropical convergence zone(ITCZ). The excessive precipitation over the Maritime Continent region and the biases in the simulated ITCZ induce anomalous northeasterlies, which are in favor of enhancing low-level winds over the North Pacific. The enhanced surface wind increases the sea surface evaporation, which contributes to the excessive upward latent heat fluxes. Thus, the SST over the Northwest Pacific cools.展开更多
文摘With the introduction of EUV lithography,the photolithographic process in 5 nm logic process can be simplified to use mostly single exposure method.In a typical 5 nm logic process,the contact-poly pitch(CPP)is 44-50 nm,the minimum metal pitch(MPP)is around 30-32 nm.And the overlay budget is estimated to be 2.5 nm(on product overlay).Although the optical resolution of a 0.33NA exposure tool(such as ASML NXE3400)can reach below 32 nm pitch,stochastics in the EUV absorption in photoresists has limited its application to smaller pitches.For the CPP mentioned above,one can use 193 nm immersion lithography with Self-Aligned Double Patterning(SADP)technique to provide good image contrast(or CDU,LWR)as well as good overlay,as for the 10 and 7 nm generations.In the BEOL,however,the 30-32 pitch cannot be realized by a single EUV exposure with enough printing defect process window.If this pitch is to be done by 193 nm immersion lithography,more than 6-8 exposures are needed with very complicated overlay result.For EUV,this can be done through self-aligned LELE with both good CD and overlay control.We have done an optimization of the photolithographic process parameters for the typical metal with a self-developed aerial image simulator based on rigorous coupled wave analysis(RCWA)algorithm and the Abbe imaging routine with an EUV absorption model which describes stochastics.We have calibrated our model with wafer exposure data from several photoresists under collaboration with IMEC.As we have presented last year,to accommodate all pitches under a logic design rule,as well as to provide enough CDU for the logic device performance,in DUV lithography,a typical minimum exposure latitude(EL)for the poly and metal layers can be set at,respectively,18%and 13%.In EUV,due to the existence of stochastics,13%EL,which corresponds to an imaging contrast of 40%,seems not enough for the metal trenches,and to obtain an imaging contrast close to 100%,which yields an EL of 31.4%means that we need to relax minimum pitch to above 41 nm(conventional imaging limit for 0.33NA).This is the best imaging contrast a photolithographic process can provide to reduce LWR and stochastics.In EUV,due to the significantly smaller numerical apertures compared to DUV,the aberration impact can cause much more pronounced image registration error,in order to satisfy 2.5 nm total overlay,the aberration induced shift needs to be kept under 0.2 nm.We have also studied shadowing effect and mask 3D scattering effect and our results will be provided for discussion.
文摘A new technology was developed to recover V2O5 from Bayer spent liquor by ion exchange.The experimental results show that in the conditions of 105℃ and 0.20-0.25 mass ratios between CaO in lime and Al2O3 in spent liquor, the precipitation rate of vanadium in Bayer liquor is more than 85%.The vanadium-bearing precipitation is leached by NaHCO3 solution.The leaching rate of vanadium can reach 85% in the conditions of 95℃, 40 g·L-1 of NaHCO3 concentration, and ventilating of CO2.The 201 × 7 type of resin has good adsorption effect on vanadium in the leaching solution.The adsorption rate is more than 94% with the flow rate of 0.09 mL·min-1·g-1 of leaching solution and the temperature of 40-50℃.By using 3 mol·L-1 of NaOH to desorb the saturated resin after adsorption at 40-50℃, a solution with more than 5 g·L-1 of V2O5 can be obtained.After roasting ammonium metavanadate that precipitates from the desorption solution when NH4Cl is added at the temperature of 500-550℃ for 2 h, V2O5 with more than 99% of purity is obtained.
文摘1 Introduction Tibet has nurmerous salt lakes.Laguocuo is one of the salt lakes,which is located to the sorthern of Ali Plateau,31°59′02″N-32°04′08″N,84°02′03″E-84°12′03″E.Its lake water is rich in potassium,magnesium,lithium,boron,rubidium,cesium and other resources.The study of
文摘Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN generated the corresponding acyl radicals, which were found to proceed in 5 exo trig or 6 endo trig cyclisations to afford high yields of cyclopentanones and cyclohexanones, The substitution groups on the substrates have played an important role on the regioselectivity of cyclisations.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0604004)the R&D Special Fund for Public Welfare Industry(Meteorology)(Grant No.GYHY201506012)
文摘In this paper, the features and possible causes of sea surface temperature(SST) biases over the Northwest Pacific are investigated based on a mixed-layer heat budget analysis in 21 coupled general circulation models(CGCMs) from phase 5 of the Coupled Model Inter-comparison Project(CMIP5). Most CMIP5 models show cold SST biases throughout the year over the Northwest Pacific. The largest biases appear during summer, and the smallest biases occur during winter. These cold SST biases are seen at the basin scale and are mainly located in the inner region of the low and mid-latitudes. According to the mixed-layer heat budget analysis, overestimation of upward net sea surface heat fluxes associated with atmospheric processes are primarily responsible for the cold SST biases. Among the different components of surface heat fluxes, overestimated upward latent heat fluxes induced by the excessively strong surface winds contribute the most to the cold SST biases during the spring, autumn, and winter seasons. Conversely, during the summer, overestimated upward latent heat fluxes and underestimated downward solar radiations at the sea surface are equally important. Further analysis suggests that the overly strong surface winds over the Northwest Pacific during winter and spring are associated with excessive precipitation over the Maritime Continent region,whereas those occurring during summer and autumn are associated with the excessive northward extension of the intertropical convergence zone(ITCZ). The excessive precipitation over the Maritime Continent region and the biases in the simulated ITCZ induce anomalous northeasterlies, which are in favor of enhancing low-level winds over the North Pacific. The enhanced surface wind increases the sea surface evaporation, which contributes to the excessive upward latent heat fluxes. Thus, the SST over the Northwest Pacific cools.
