Abstract: The present invention provides an ashing method using rapid heat transfer under high pressure. The present method, applicable to all photoresist ashing processes, can rapidly remove hardened photoresists without popping at the ashing step by baking high dose ion implanted silicon substrate on a hot plate, enhancing the ashing quantity, by drastically reducing the ashing process time, while allowing conventional equipments to be used further. The present method comprises an in situ baking step, wherein a silicon substrate is baked for a predetermined time period under a pressure of 10 Torr or more while it is placed on a hot plate; a vacuumizing step, wherein a stable vacuum status is achieved while the silicon substrate is placed on the hot plate; a gas processing step, wherein selected reaction gas is introduced into a reaction chamber; and an ashing step, wherein plasma is generated until almost all of the photoresists are removed.