| 摘要 |
PURPOSE:To form a pattern precisely by a method wherein, after a photosensitive polyimide film is spread on a substrate to be processed, temperature gradient in the film thickness direction is so made that the temperature of the film in the vicinity of the substrate interface is higher than the upper layer part, pre-baking is performed, and then exposure and development are performed. CONSTITUTION:High temperature hot plates 1 and low temperature hot plates 2 are alternately arranged. The plates 1 are kept at a temperature wherein photosensitive functional groups added to polyimide precursor decompose. The plates 2 are kept at a low temperature, e.g. normal temperature. A rail 3 is lifted at a specified time, and moved in the arrow direction. Thereon an Si substrate 4 is so arranged that the spread film faces upward. While the rear is suitably vacuum-sucked, the substrate is moved, and the interface side temperature of the spread film for the substrate is increased, thereby decomposing the photosensitive functional groups whose heat resistance is inferior. When selective exposure is performed after the above baking process, crosslinked polymerization is generated on the surface side of the spread film, because photosensitive groups exist. Crosslinked polymerization, however, is not generated on the substrate side. The gradient of crosslinking density is generated in the spread film, so that the lower part can be easily dissolved by developer. |
