Temperature effects on positive electron resists irradiated with electron beam and deep‐UV light

The exposure characteristics of poly(methyl methacrylate) (PMMA) and poly(methyl isopropenyl ketone) (PMIPK) were studied with electron beam and deep‐UV light irradiation at different temperatures (20–160°C). The sensitivities and γ(contrast) values for electron beam irradiation show small temprature effects, but those for deep‐UV light irradiation revel relatively large temperature effects. The result in which γ (contrast) values for the electron beam irradiation as a whole are significantly larger than for the deep‐UV light irradiation is related to the molecular weight dispersity of irradiated resists. The result in which γ(contrast) for PMMA is larger than that for PMIPK at given development conditions is also related to the molecular weight ratios of the original and irradiated resists. The thickness reduction and negative inversion (crosslinking) compete under a large dose of electron beam irradiation, but the latter is scarcely apparent under deep‐UV irradiation. The PMMA sensitivity for deep‐UV irradiation diminishes in O 2 gas flow compared with the irradiation in N 2 gas flow, but PMIPK sensitivity is not influenced by O 2 . From these results, the different decomposition mechanisms are discussed.