Apparatus for applying liquid agent on surface of rotating substrate

An apparatus for applying liquid agent to a substrate, said apparatus comprising:

• (a) means for supporting and rotating a substrate about a spin axis;
• (b) means for applying liquid agent to said substrate;
• (c) a cup member for preventing liquid agent from scattering, said cup member including a circumferential wall having an inner circumferential surface and an outer circumferential surface, said circumferential wall forming a generally conical surface having an upper portion, said upper portion including a plurality of openings, each of said openings extending through said circumferential wall and being slightly slanted with respect to a direction tangent to the inner surface of the circumferential wall;
• (d) first cleaning agent supplying means for supplying cleaning agent to said inner circumferential surface through said openings, said cleaning agent supplying means being integrally formed on said outer circumferential surface of said circumferential wall;
• (e) a slanted member with a slanted upper surface for regulating and guiding air, liquid agent and cleaning agent downwardly through said cup member, said slanted surface being located below said supporting means, said slanted surface including an upper portion with a plurality of openings formed therein, said slanted member having a rear surface and a lower edge, each of said openings formed in said upper portion of said slanted surface extending through said slanted member and being slightly slanted with respect to a direction tangent to the slanted surface;
• and
• (f) second cleaning agent supplying means for supplying cleaning agent to said slanted surface by supplying cleaning agent through said openings of said slanted surface, said second cleaning agent supplying means being formed on said rear surface of said slanted member;
• wherein said apparatus includes fine irregularities on said inner circumferential surface for spreading cleaning agent.