Polyimide thin films have been deposited by evaporation in vacuum. Their etch rate and surface quality during reactive ion etching (RIE) in CF4/O-2 gas mixture on a quartz substrate holder have been investigated. The etch rate depends on the gas composition in a way similar to solution-cast polyimide layers and has a maximum at 20% CF4. Scanning electron microscopy has revealed a needle-like surface at small CF4 concentrations and a smooth morphology when etching is carried out in fluorine-rich gas mixture. X-ray photoelectron spectroscopy analysis has been carried out in order to investigate this effect. The results are applicable to RIE of vapor phase deposited polyimide as a planarizing layer for lithography based on "all-dry" processing.