The bifunctional chelating agents N,N,N',N'',N''-pentakis(carboxymethyl)-1- [(4-aminophenyl)methyl]-diethylenetriamine and N,N,N',N'',N''-pentakis(carboxymethyl)-1-[(4-aminophenyl)methyl]-4- methyldiethylenetriamine were prepared in six-step syntheses in overall yields of 38% and 31%, respectively. The use of bromoacetate esters in the synthesis allowed large-scale flash chromatographic purification of reaction products. The synthesis of N,N,N',N'',N''-pentakis(carboxymethyl)-1- [(4-aminophenyl)-methyl]-4-methyldiethylenetriamine resulted in a mixture of two diastereomers. Chelation of yttrium-(III) with these bifunctional chelating agents resulted in 1:1 chelates. In the case of N,N,N',N'',N''-pentakis(carboxymethyl)-1-[4- aminophenyl)methyl]diethylenetriamine, two diastereomers were observed upon chelation, as expected. In the case of N,N,N',N'',N''- pentakis(carboxymethyl)-1-[(4-aminophenyl)-methyl]-4- methyldiethylenetriamine, only three of the four anticipated diastereomers were observed.
Line edge roughness evolutions in EUV resist patterns are investigated. Three dimensional scanning electron microscopy images show the pattern sidewall roughness to be highly anisotropic and the roughness to be propagating from the resistsubstrate interface up the resist pattern sidewall. In ultrathin resist films, (film thickness ca. 100 nm and below) roughness is found to be fully correlated from the resist-substrate interface to the resist-air interface. This behavior is seen regardless of the resist platforms being used.Underlayer stack roughness contributions to the pattern sidewall roughness leading to resist LER were examined and no correlations between the two were found. At the same time, the chemical properties of the underlayer stacks are shown to have strong influences on the resist roughness and process performance. Exact mechanisms behind this are not clearly understood at present.
Negative working photodefinable benzocyclobutene formulations capable of obtaining patterned dielectric films from 1 to 20 microns thick are being developed using bisaryl azides as photocrosslinkers. Three different formulations are used to cover this range of film thicknesses. The formulations are very sensitive to the 365 nm and 405 nm wavelengths of light (i-line and h-line) of the high pressure mercury spectrum and require low exposure doses to produce resolved patterns. Twenty five micron round and square vias with sloping sidewalls (geometry good for metallization) have been successfully patterned in 10 micron thick films. The photodefined patterns can be obtained with good film retention using several developing solvents including: Stoddard solvent, ProglydeTM DMM, and n-butyl butyrate.
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