Edge-exposure tool with an ultraviolet (uv) light emitting diode (led)

An edge-exposure tool comprising:

• a process chamber;
• a workpiece table in the process chamber, wherein the process chamber is configured to support a workpiece covered by a photosensitive layer;
• a light emitting diode (LED) in the process chamber, wherein the LED is configured to emit radiation towards the workpiece;
• a first lens having a light-receiving surface and a light-emitting surface on opposite sides of the first lens and respectively facing the LED and the workpiece table, wherein the first lens is configured to receive the radiation at the light-receiving surface;
• and
• a controller configured to control the LED to expose an edge portion of the photosensitive layer, but not a center portion of the photosensitive layer, to the radiation emitted by the LED, wherein the edge portion of the photosensitive layer extends along an edge of the workpiece in a closed path to enclose the center portion of the photosensitive layer.

A method for edge exposure, the method comprising:

• arranging a wafer within a process chamber, wherein the wafer is covered by a photosensitive layer;
• exposing an edge portion of the photosensitive layer, but not a center portion of the photosensitive layer, to ultraviolet (UV) radiation generated by a light emitting diode (LED), wherein the UV radiation chemically changes the edge portion of the photosensitive layer, wherein the edge portion of the photosensitive layer extends along an edge of the wafer in a closed path to encircle the center portion of the photosensitive layer, and wherein the LED is in the process chamber and driven by a driver circuit;
• and
• rotating the wafer during the exposing of the edge portion;
• wherein the exposing of the edge portion comprises:
• generating, and providing an LED controller with, a shutter-open command for a wafer edge exposure (WEE) lamp, wherein the generating and the providing are performed by an exposure controller independent of the LED controller;
• and
• setting the LED to ON in response to the shutter-open command using the driver circuit, wherein the setting is performed by the LED controller and the LED controller is independent of the driver circuit.