Masaya Asano

Molecular Orientation in Polyimide Films Having Rodlike Molecular Skeleton Formed on Silicon Substrate

Polarized infrared spectroscopy was used to characterize molecular orientation in polyimide films deposited on silicon wafers. The films were constructed from a single polyimide having a rodlike molecular skeleton. The degree of in-plane orientation at the interface with the wafer in the film varied with film thickness. On the other hand, that at the surface was almost constant. As a result of the difference in the thermal coefficient of expansion related to the degree of in-plane orientation between the surface and interface regions, thick films curled after they were stripped off the wafers. This phenomenon was presumed to be caused by the variation in the amount of the residual solvent in the polyimide precursor film with film thickness before the thermal cycle for imidization.

Effect of Thermal Curing on Molecular Orientation in Polyimide Films Having Rodlike Molecular Skeleton Formed on Substrates

Films of a single polyimide having a rodlike molecular skeleton of uniform thickness were prepared on silicon and quartz substrates under several different heating rates during the thermal curing cycle. The molecular orientation in the cured polyimide film was evaluated by polarizing infrared and visible light investigation. The molecular orientation in the film was very sensitive to the heating rate during the curing cycle at the interface with the substrate, but less sensitive to that at the surface. The rodlike molecules in the film which were slowly heated were highly oriented and nearly parallel to the film plane, whereas those which were quickly heated were randomly oriented at the interface. It was shown that the increase in thermal stress in the polyimide film with increasing heating rate reflected the degree of decrease of the in-plane orientation.

Stress in polyimide films having a rodlike molecular skeleton formed on a silicon substrate

Stress measurements of polyimide films deposited on silicon wafers were performed in situ during the curing and cooling cycles. The films were constructed from a single polyimide having a rodlike molecular skeleton. The stress in the film varied with film thickness. The stress before curing decreased with increasing film thickness. On the other hand, the stress after the thermal cycle increased with increasing film thickness, resulting from the increasing thermal coefficient of expansion. This phenomenon was thought to be caused by the decrease in the degree of the in‐plane orientation of the polyimide molecular chain with decreasing stress before the curing process.

Effect of Thermal Curing on Thermomechanical Properties of Polyimide Films Having Rodlike Molecular Skeleton Formed on a Silicon Substrate

Stresses in polyimide films coated on silicon wafers were measured in situ during the curing and cooling cycles. The films had a single rodlike molecular skeleton. Stress measurements were performed on films of uniform thickness under several different heating rates during the curing cycle. After the stress measurements, the cured polyimide films were examined by thermal mechanical analysis. The stress after the curing cycle increased with increasing heating rate during the curing cycle. Similarly, the thermal coefficient of expansion of the cured polyimide film increased with increasing heating rate. This phenomenom was thought to be caused by the decrease in the degree of in-plane orientation of the polyimide molecular chain with increased heating rate. The in-plane orientation was presumed to be influenced by the evaporation rate of the residual solvent.

New novolak-based positive EB resist, EBR-900 M-1

For the fabrication of 64 M and 256 MDRAM reticles, EB resists which have both high resolution and excellent dry etch resistance will be required. It is also particularly important to have high dry etch resistance for the manufacture of phase shift masks. For the development of traditional EB resists, organic solvents are typically used. However from the safety standpoint aqueous developers would be preferred. To meet these requirements a new positive type, aqueous developable EB resist, named EBRTM-900 M-1, has been developed. EBRTM-900 M-1 shows resolution down to 0.3 micrometers , good sensitivity, 1.6 - 5 (mu) C/cm2 (10 kV) for practical use, excellent dry etch durability same as positive optical resists, and can be developed by aqueous alkaline developers. This resist is not a chemically amplified type and shows excellent post exposure stability and no delay effect. The sensitivity of the coated film does not change in 50 days and the exposed films shows practically no change for up to 7 days in air and 2 days in vacuum. This resist has high sensitivity, not only for E-Beam, but also for argon-ion laser, 363.8 nm. Field data using production EB exposure systems will be presented. The lithographic properties using a CORE- 2564 scanned laser system, are also studied.

Stress measurement Of BPDA/PDA Polyimides From Poly(Amic Acid) And Photosensitive Polyimide Precursors On Silicon

The intrazeolite chemistry of the two germylene complexes Cl 2 (THF)GeM(CO) 5 (M = Mo, W) was studied with x-ray absorption spectroscopy (Ge, Mo, W edge EXAFS) and in-situ FTIR/TPD-MS techniques. The slightly decarbonylated GeMo complex interacts with the framework of NaY zeolite at room temperature and retains the Ge-Mo bond up to about 100° C. In proton-loaded HY zeolite, framework interactions increase at elevated temperature, and the attached complex retains the Ge-Mo bond up to about 120° C. The Ge-Mo bond is cleaved at higher temperatures. MoC1 x and Mo-Mo species are formed in NaY and HY zeolite, respectively, while GeCl x fragments are anchored to the zeolite framework. The complex Cl 2 (THF)GeW(CO) 5 retains all five CO ligands up to about 100° C in both NaY and the proton form. Detectable anchoring occurs at room temperature in NaY and at about 80° C in the proton form. WC1 x species are formed upon cleavage of the Ge-W bond at higher temperatures.