A substrate processing apparatus is used in the process of manufacturing a semiconductor, a liquid crystal panel, or the like, to treat a surface to be treated of a substrate such as a wafer or a liquid crystal substrate with a chemical solution, rinse the surface after the chemical treatment with a rinsing liquid, and then dry the substrate after the rinsing.
In the drying process, problems such as pattern collapse around, for example, the memory cell or the gate have occurred due to recent miniaturization along with higher integration and higher capacity of semiconductors. This is caused by the spacing and structure between the patterns, the surface tension of the rinsing liquid, and the like.
Therefore, in order to suppress the pattern collapse, there has been proposed a substrate drying method using a volatile solvent (e.g., IPA: 2-propanol, isopropyl alcohol) with a surface tension smaller than that of the rinsing liquid (e.g., DIW: ultrapure water). In the substrate drying method, the substrate is dried by replacing the rinsing liquid on the treated surface of the substrate with a volatile solvent. At this time, to promote the drying, the substrate may be heated by a lamp located above the surface to be treated of the substrate to dry the substrate.
In the chemical treatment step, a high-temperature treatment of 150° C. or more may be performed using sulfuric acid or phosphoric acid as a chemical solution. In this case, the chemical solution is heated to 150° C. or higher to be used in the treatment. Therefore, the chemical solution on the surface to be treated of the substrate is heated to a high temperature of 150° C. or higher by the lamp located above the surface to be treated.
However, in the drying process and the chemical treatment process, since the lamp is located above the surface to be treated of the substrate, a mist or particles of the treatment liquid adhere(s) to the surface of the lamp during the substrate processing. The adhering matter such as a mist or particles of the treatment liquid drops from the surface of the lamp and adheres to the surface to be treated of the substrate. This may result in the contamination of the substrate.
Meanwhile, a common substrate processing apparatus is provided with an ultra-low penetration air (ULPA) filter or a high efficiency particulate air (HEPA) filter. The clean air that has passed through the filter flows in the substrate processing apparatus as downflow (vertical laminar flow), and the inside of the substrate processing apparatus is kept clean. As a result, particles are prevented from adhering to the inside of the substrate processing apparatus, in particular, the surface to be treated of the substrate.
However, in the aforementioned substrate processing apparatus, since the lamp is located above the surface to be treated of the substrate, clean air directed from the filter toward the surface to be treated of the substrate is interrupted by the lamp and is not sufficiently supplied to the surface to be treated of the substrate. For this reason, it is difficult to remove particles from the surface to be treated of the substrate and its surroundings. As a result, the substrate is contaminated.