Reinhard Schulz

Photolysis and gas phase pyrolysis of 1,2,3-benzoselenadiazole - matrix-isolation of benzoselenirene

Abstract Based on comparative studies on 1,2,3-benzothiadiazole benzoselenirene is identified as an intermediate in the low temperature photolysis and gas phase pyrolysis of 1,2,3-benzoselenadiazole by IR spectroscopy.

IR and UV matrix photochemistry and solvent effects: the isomerization of diazocyclohexadienones (ortho quinone diazides) — detection of molecules with the 1,2,3-benzoxadjazole structure. A UV/Vis and IR absorption and UV photoelectron spectroscopic investigation

Abstract 6-Diazo-2,4-cyclohexadienone and derivatives with fluoro, chloro, methyl, tert -butyl and methoxy substituents have been investigated by UV/ Vis absorption, IR absorption and UV photoelectron spectroscopy. Spectral results obtained in the gas phase, in an argon matrix at 10 K and in n -hexane solution at room temperature reveal an equilibrium with the respective 1,2,3-benzox- adiazole isomers, thus disproving current textbook opinions. The 1,2,3-benzoxadiazole structure is derived from the agreement of observed and calculated vertical ionization energies, characteristic IR and UV/Vis absorption bands as well as selective IR and UV photochemical transformations. The relative concentration of the respective l,2,3-benzoxadiazole in equilibrium with the diazoketone isomer strongly depends on the substituents and on solvent effects. The diazoketone structure is stabilized by hydrogen bonding and polar interactions. The most stable 1,2,3- benzoxadiazole in this study, the 5,7-di- tert -butyl derivative, is at least 6.3 kJ mol −1 more stable than its diazocyclohexadienone valence isomer, whereas 2,3,4,5-tetrafluoro-6-diazo-2,4-cyclohexadienone and 3-methoxy-6-diazo-2,4-cyclohexadienone did not isomerize to a notable extent. Energetic considerations for the stabilization of 1,2,3-oxadiazoles are discussed and compared with experimental and theoretical findings.

Uv photoelectron spectrum of o-xylylene — detection of a low-energy non-koopmans (shake-up) ionization

Abstract The HeI spectrum of the transient title compound has been obtained using the variable-temperature photoelectron- spectroscopy technique. Strong experimental evidence for a low-energy shake-up structure in the ionization pattern of the polyene-like system is presented. Agreement between the semi-empirical PERTCI and experimental ion-state energies is very good.

Structural design of ketal and acetal blocking groups in two-component chemically amplified positive DUV resists

In the present study, protecting groups of moderate stability, such as acetals and ketals, were investigated as pendant blocking groups in polyvinyl phenols. Polymers were obtained by reacting enol ethers with the phenolic side groups to form acetal or ketal blocked phenols. Decomposition temperatures, glass transition temperatures, and molecular weights of the resulting polymers were monitored and correlated with the protecting group structure. Stability of the protecting groups can be explained by protonation occurring at either of the two oxygen sites, making two cleavage routes possible. Secondary reactions of the released protecting groups in the resist film were investigated and discussed. The structure of the protecting group was designed in order to meet basic resist properties such as resolution/linearity, DOF, post exposure delay latitude and thermal stability. A Canon FPA 4500 (NA equals 0.37) and a GCA XLS exposure tool (NA equals 0.53) were used for the optimization process. A preoptimized resist formulation based on the above criteria exhibits 0.23 micrometers line/space resolution, 0.8 micrometers focus latitude at 0.25 micrometers resolution and approximately two hours post exposure delay latitude.

Advanced positive photoresists for practical deep-UV lithography

New positive tone deep UV resists with enhanced post-exposure delay (PED) latitude and process latitude are presented. Additives and functionalized sulfone terpolymers are tailored to optimize the dissolution properties and process stability. Adjustment of the dissolution rate is used as a design criterion for optimizing the resist performance. RX 165 resist, optimized using the above criteria, exhibits 0.25 micron line/space resolution, 0.8 micrometers focus latitude at 0.275 micrometers resolution, and 1 hour post exposure delay latitude.