Photo-cvd apparatus

Abstract

Abstract PURPOSE:To prevent a material from being deposited on the rear face of a light transmission window while enabling it to be deposited on a substrate more rapidly, by once optically enlarging a diameter of a laser beam and then focusing it onto the substrate. CONSTITUTION:A laser beam 2 is once enlarged by a concave lens 5 and directed to a point 20 on a substrate 8 by a convex lens b. A chamber 10 is filled with raw gas, which is excited and decomposed by the laser beam 2 between the rear face of a light transmission window 21 and the substrate surface 20. Since the raw gas is excited by absorbing photons, probabilities of the raw gas being excited are proportional to densities of photons passing therethrough. That is, if the intensity of laser beam is constant, areas of the laser beam transmitted by the light transmission window 7 are inversely proportional to probabilities of the raw gas being excited near the window 7. For that reason, the area of the laser beam 2 to be transmitted by the window 7 is enlarged by means of the convex lens 5. Accordingly, concentration of the raw gas excited and decomposed near the window is low.

Inventors

• 👤 Yasuyuki Hashizume
• 👤 靖之 橋詰

Bibliographic Details