| 摘要 |
PURPOSE:To control the flow of a gas made radical or decomposed by optical excitation and a gas for protection and thereby to prevent the deterioration of an optical window by a method wherein a second gas is decomposed by excitation and further made to react with a substrate, and thereafter the decomposed gas and first and second gases are discharged from the back side of the substrate. CONSTITUTION:Pressure difference plates 6 are provided for maintaining a pressure difference in a gas flow channel. A second gas g2 used for processing a substrate 1 is made to flow on the opposite side of these pressure difference plates 6 and further flow down along these plates and is applied uniformly on the substrate 1. In other words, the pressure difference plates 6 are shielding plates operating also for regulating a flow. The second gas g2 flowing down on the substrate 1 is excited by a light 3 passing through an optical window 4, and is thereby made into plasma or decomposed, so as to be activated to react with the substrate. The decomposed gas and first and second gases are discharged from a discharge port 5 provided on the back side of the substrate. In terms of the gas flow channel, accordingly, the pressure is highest on the first gas g1 side and turns lower sequentially toward the substrate side. Moreover, the gas flow is regulated to be in strate by the operation of the shielding plates 6 having the effect of flow regulation, and thus the second gas seldom reaches the surface of the optical window 4. |
