Method of and apparatus for heat-treating exposed substrate
A substrate subjected to a pattern exposure process is transported to a flash bake unit. The flash bake unit performs a post-exposure bake process in which flashes of light are directed from flash lamps onto a surface of the substrate held on an upper surface of a cooling plate to momentarily heat the surface of the substrate, thereby causing crosslinking, deprotection or decomposition and the like of resist resin to proceed by using active species produced in a resist film by a photochemical reaction during the pattern exposure process as an acid catalyst, so that the solubility of only the exposed portion of the resist film in a developing solution is locally changed. The flash heating treatment performed by the irradiation with flashes of light requires extremely short treatment time of not greater than one second. This reduces the diffusion length of acid during the post-exposure bake process.
1. A method of heat-treating an exposed substrate having an exposed surface obtained by a pattern exposure process, by performing a post-exposure bake process on the exposed substrate, comprising the steps of:
(a) putting a substrate into a chamber after a chemically amplified resist film formed on the exposed surface of the substrate has been exposed to light;
(b) simultaneously irradiating the entirety of the exposed surface of said substrate put in said chamber with flashes of light to perform a post-exposure bake process; and
(c) causing a chemical reaction of at least one of crosslinking, deprotection and decomposition of the resist film to proceed by using active species produced in said chemically amplified resist film by a photochemical reaction during the pattern exposure process as an acid catalyst.
2. The method according to claim 1 , further comprising the steps of:
(c) exhausting air from said chamber; and
(d) supplying humidified air into said chamber.
3. The method according to claim 1 , wherein
said substrate is irradiated with flashes of light in said step (b) while being held on a cooling plate in said chamber.
4. The method according to claim 3 , wherein
said substrate is held on said cooling plate continuously before, during and after the irradiation with flashes of light.
5. The method according to claim 1 , wherein
the time for heating treatment by the irradiation with flashes of light in said step (b) is not greater than one second.
6. The method according to claim 1 , wherein
light with a wavelength less than 300 nm is removed from the flashes of light directed onto the surface of said substrate in said step (b).
7. A heat treatment apparatus for performing a post-exposure bake process on an exposed substrate having an exposed surface obtained by a pattern exposure process, comprising:
a chamber configured for receiving therein a substrate having a surface provided with a chemically amplified resist film exposed to light;
a cooling plate configured for placing and holding said substrate thereon in said chamber;
an exhaust part configured for exhausting air from said chamber;
a humidified air supply part configured for supplying humidified air into said chamber;
a flash lamp configured for simultaneously irradiating the entirety of the exposed surface of said substrate held on said cooling plate with flashes of light to cause a chemical reaction of at least one of crosslinking, deprotection and decomposition of the resist film to proceed by using active species produced in said chemically amplified resist film by a photochemical reaction during the pattern exposure process as an acid catalyst; and
a filter configured for removing light with a wavelength less than 300 nm from the flashes of light directed from said flash lamp onto said substrate.