| 摘要 |
PROBLEM TO BE SOLVED: To achieve a reliable, long-life plasma-treating apparatus by preventing a microwave-introducing window material from being cracked. SOLUTION: For solving the conventional, technical problem, the thickness of the window material is optimized. More specifically, the thickness of a section around a window that easily becomes a breakdown starting point due to the operation of tensile stress is increased, and a central section where electromagnetic waves pass is thinned, thus minimizing thermal stress due to the absorption of electromagnetic waves. Further, tensile stress at a periphery where a breakdown easily occurs is minimized to prevent the window material from being damaged. More specifically, a transmission window for the electromagnetic waves for excitation in a plasma-generating apparatus is made of a ceramics material and the thickness at the center is larger than a peripheral section. |
