Apparatus and method for spin processing

A track system comprising:

• a wafer coater module comprising:
• a wafer holder configured to spin a wafer held such that a surface to be coated and an edge region of a backside are exposed, the backside being opposite the surface to be coated;
• a rotary drive configured to spin the wafer holder about a central axis normal to the wafer, wherein spinning the wafer holder spins the wafer held by the wafer holder;
• a nozzle configured to be positioned above the surface to be coated and pour liquid onto the surface to be coated;
• an air knife comprising a plenum having a gas inlet coupled to a gas blower and a slot for an air curtain to exit, the air knife configured to position the slot proximate the backside and tilted to direct the air curtain toward the backside at a grazing angle of incidence to create a gas-flow radially outward along the exposed backside, the grazing angle of incidence being an angle between a tangent to a major surface of the backside of the wafer and a direction of incidence of the air curtain towards the backside;
• and
• an annular duct disposed to be circumferentially around the wafer when spun by the wafer holder, the duct being configured to collect liquid and solid particles dislodged by the spinning and the gas-flow and ejected off an edge of the wafer;
• and
• a light source and a camera coupled to a controller to acquire and transmit photographic images of the surface of the wafer to an inspection device.

Equipment for coating a wafer, the equipment comprising:

• a rotary drive configured to spin a wafer holder;
• a nozzle configured to pour liquid onto a surface of the wafer to be coated at a front side of the wafer;
• an annular duct disposed circumferentially around the wafer when the wafer is spun by the wafer holder, the duct configured to collect material ejected off an edge of the wafer;
• and
• an air knife disposed proximate a backside of the wafer, the backside being opposite the front side, wherein the air knife is configured to blow an air curtain through a slot onto an exposed edge region of the backside at a grazing angle of incidence to flow gas radially outward along the backside toward the annular duct, the grazing angle of incidence being an angle between a tangent to a major surface of the backside of the wafer and a direction of incidence of the air curtain towards the backside, wherein the air knife is configured to adjust the grazing angle of incidence to a selected angle.