1. Field of the Invention
This invention relates to a coating treatment method and a coating treatment apparatus that form a hard mask film on a front surface of a substrate and remove an edge portion of the hard mask film.
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-171605, filed in Japan on Aug. 2, 2012, and Japanese Patent Application No. 2013-124314, filed in Japan on Jun. 13, 2013, the entire contents of which are incorporated herein by reference.
2. Description of the Related Art
Generally in a semiconductor manufacturing process, a photolithography process including a resist coating treatment of supplying a resist solution being a treatment solution to the front surface of the substrate, such as a semiconductor wafer while rotating the substrate horizontally held to form a resist film, exposure processing of exposing the resist film into a predetermined pattern, a developing treatment of developing the exposed resist film and so on is performed to form a predetermined resist pattern on the wafer. For example, a coating and developing treatment system in which an exposure apparatus is connected to a coating and developing treatment apparatus is usually used for the photolithography process.
In the photolithography process in the coating and developing treatment system, the multi-patterning technique of performing resist coating, exposure and developing treatment a plurality of times has been actively discussed with microfabrication of 20 nm or finer in recent years, but the etching technique becomes very difficult due to complication of the process.
Hence, to further improve the precision of the etching technique, a hard mask capable of providing a large selection ratio in etching is employed as a lower-layer film of an organic film and an inorganic film. As the hard mask, for example, a hard mask composed of an organic polymer or a metal hard mask containing an organic substance and an inorganic substance is employed. Further, a hard mask film (lower-layer film) of the hard mask is required to be formed by the spin coating method in consideration of cost and the like (see International Publication Pamphlet No. WO2007/020979).
In forming the hard mask film by the spin coating method, the hard mask film can be formed by supplying (discharging) a hard mask solution to the front surface of the substrate rotated around the vertical axis to diffuse the hard mask solution and then drying (baking) the hard mask solution. However, the hard mask solution flows around and adheres to a beveled portion at the edge portion of the substrate, that is, a portion obtained by chamfering a portion forming an elevation angle at the peripheral end portion of the substrate in the spin coating method. In particular, the hard mask containing an organic substance and an inorganic substance contains metal such as titanium, aluminum, tungsten or the like, so that if the adherence occurs, the substrate and the inside of the apparatus may be contaminated with metal.
As means for removing the hard mask film adhering to the beveled portion of the substrate, there is a conceivable method of discharging a cleaning solution (organic solvent for dissolving the hard mask film) to the beveled portion of the rotated substrate to remove the hard mask using an existing cleaning technique (Japanese Patent Laid-open Patent Publication No. 2010-118519) of cleaning the beveled portion of the substrate.
However, the hard mask film is formed by being applied to the front surface of the substrate and then dried (baked) and therefore cannot be sufficiently removed by the existing cleaning technique for the beveled portion of discharging the cleaning solution (organic solvent dissolving the hard mask film) to the beveled portion of the rotated substrate to remove the hard mask film, so that the hard mask film remains at the beveled portion of the substrate, and contamination by the hard mask film adhering to the substrate adversely affects subsequent treatments on the substrate, such as resist treatment, exposure processing, developing treatment and so on. Further, particularly the hard mask containing an organic substance and an inorganic substance has a problem of metallic contamination of the substrate and the inside of the apparatus.