Method and apparatus for coating a semiconductor wafer

A method for removing coating material from an edge of a semiconductor wafer having front, back and edge surfaces, said wafer having coating material deposited on said front and edge surfaces of said wafer, the method comprising the steps of:

• a) directing solvent of said coating material to point on a peripheral area of one of said surfaces of said wafer;
• b) rotating said wafer to deliver said solvent over said peripheral area to dissolve and remove coating material thereon, said rotation producing a flow of gas radially outward of said front surface and resulting in said flow from said front surface carrying particles of said removed coating material and solvent;
• and
• c) directing a steady flow of clean gas radially outward of said back surface of said wafer in a laminar flow at the wafer edge, and into substantially matching relation with the flow thereat of the particle containing gas to preclude the gas borne particles thereof from reaching said back or front surface.

A spin coating apparatus for coating a surface of a semiconductor wafer having a front and back surface, the apparatus comprising:

• a) an apparatus housing;
• b) coating dispensing means extending within said housing for directing coating material to a centrally located point on a front surface of a wafer;
• c) chuck means positioned within said housing for engaging a rear surface of a wafer so as to present a front surface thereof to said coating dispensing means to receive said coating material and for rotating the engaged wafer to spread said coating material over its front surface, said rotation producing a flow of gas, carrying particles of said coating, radially outward of said front surface;
• d) an open ended containment member terminating at its open end in a ring surface spaced from a peripheral portion of the back surface of an engaged wafer to define a narrow channel of large radial width between said ring surface and said back surface, the outer diameter of said ring surface being at least substantially equal to the diameter of said wafer such that said channel extends at least substantially to the edge of said wafer, and said ring surface having a radial width sufficiently larger than its spacing from said wafer to provide, when said member is pressurized, a laminar gas flow outwardly from said channel;
• and
• e) pressurizing inlet means extending into said chamber for pressurizing said chamber from a source of clean gas, independent of gases within said housing, to provide a steady flow of said clean gas outwardly through said channel in laminar flow at the edge of the engaged wafer, and into substantially matching relation to the flow thereat of said particle containing gas from the front surface to preclude the gas borne particles thereof from reaching said back and front surface.

A spin coating apparatus for removing coating from the edge surface of a semiconductor wafer having a front, back and an edge surface, the apparatus comprising:

• a) an apparatus housing;
• b) solvent dispensing means extending within said housing for directing solvent of said coating to a peripheral area of a wafer;
• c) chuck means positioned within said housing for mounting and rotating a wafer to present a peripheral area thereof to said solvent dispensing means so as to deliver said solvent to said peripheral area to remove coating therefrom, said rotation producing a flow of particle containing gas, carrying particles of both removed coating and said solvent, radially outward of said front surface;
• d) an open ended containment member terminating at its open end in a ring surface closely spaced from a peripheral portion of a back surface of said mounted wafer to define a chamber between said member and said back surface and a narrow channel of large radial width between said ring surface and said peripheral portion, said ring surface having a radial width sufficiently larger than its spacing from said wafer to provide, when said member is pressurized, a laminar gas flow outwardly from said channel, and the outer diameter of said ring surface being at least substantially equal to the diameter of said wafer such that said channel extends at least to the edge of said wafer;
• and
• e) pressurizing inlet means extending into said chamber for pressurizing said chamber from a source of clean gas, independent of gases within said housing, to provide a steady flow of said clean gas outwardly through said channel in laminar flow at the edge of the mounted wafer and into substantially matching relation to the flow thereat of said particle containing gas from the front surface to preclude the gas borne particles thereof from reaching said back and front surface.

A method for coating a surface of a semiconductor wafer having a front and back surface, the method comprising the steps of:

• a) depositing a coating material on said front surface;
• b) rotating said wafer to spread said coating material over said front surface, said rotation producing a flow of gas containing particles of said coating material radially outward of said front surface;
• and
• c) directing a flow of clean gas radially outward of said back surface of said wafer into substantially matching relation with the flow at the wafer edge of the particle containing gas to preclude the gas borne particles thereof from reaching said back or front surface, said directing step including positioning an open ended containment member in spaced relation to said back surface of said wafer, said containment member terminating at its said open end in a top ring surface, said wafer having a peripheral portion of its said back surface spaced from said ring surface to define a channel between said peripheral portion and said ring surface with a chamber internally thereof, said channel extending substantially to the edge of said wafer, said ring surface having a relatively wide top surface providing a channel of large radial width as compared to its height, and said directing step includes pressurizing said channel from a source of substantially clean gas to provide a flow thereof outwardly through said channel into said matching relation at the wafer edge with said flow of gas from said front surface, and the outer diameter of the ring surface of said containment member is substantially equal to the diameter of said wafer such that said channel substantially extends to the edge of said wafer.

A spin coating apparatus for coating a surface of a semiconductor wafer having a front and back surface, the apparatus comprising:

• a) an apparatus housing;
• b) coating dispensing means extending within said housing for directing coating material to a centrally located point on a front surface of a wafer;
• c) chuck means positioned within said housing for mounting and rotating a wafer to spread said coating material over a front surface thereof, said rotation producing a flow of gas, carrying particles of said coating, radially outward of said front surface;
• d) an open ended containment member terminating at its open end in a ring surface closely spaced from a peripheral portion of a back surface of a mounted wafer to define a narrow channel between said ring surface and said back surface, said channel extending substantially to the edge of said mounted wafer, and said ring surface having a relatively wide top surface providing a channel of large radial width as compared to its height;
• and
• e) inlet means extending into said containment member for pressurizing said channel from a source of clean gas:
• independent of said gas from said front surface and free of the particles borne thereby, to provide a steady flow of said clean gas outwardly through said channel into substantially matching relation to the flow at said wafer edge of the particle containing gas from said front surface to preclude the gas borne particles thereof from reaching said back or front surface, and the outer diameter of the ring surface of said containment member is substantially equal to the diameter of said wafer such that said channel substantially extends to the edge of said wafer.

A spin coating apparatus for removing coating from the edge surface of a semiconductor wafer having a front, back and an edge surface, the apparatus comprising:

• a) an apparatus housing;
• b) solvent dispensing means extending within said housing for directing solvent of said coating to a peripheral area of a wafer;
• c) chuck means positioned within said housing for mounting and rotating a wafer to deliver said solvent to the edge surface of the mounted wafer to remove coating therefrom, said rotation producing a flow of particle containing gas, carrying particles of both removed coating and said solvent, radially outward of the front surface of said wafer:
• d) an open ended containment member terminating at its open end in a ring surface closely spaced from a peripheral portion of a back surface of said mounted wafer to define a chamber between said member and said back surface with an open narrow channel defined between said ring surface and said back surface, said channel extending substantially to the edge of said wafer, and said ring surface having a relatively wide top surface providing a channel of large radial width as compared to its height;
• and
• e) pressurizing inlet means extending into said containment member for pressurizing said chamber from a source of clean gas, independent of gases within said housing, to provide a steady flow of said clean gas outwardly through said channel into substantially matching relation to the flow at said wafer edge with said flow of particle containing gas from said front surface to preclude the gas borne particles thereof from reaching said back or front surface, and the outer diameter of the ring surface of said containment member is substantially equal to the diameter of said wafer such that said channel substantially extends to the edge of said wafer.