Patent ID: 6721037
Filing Date: 2004-04-13
Classification: G03F

Abstract:
Device for exposing by irradiation a peripheral area of a wafer having a notch in the peripheral area and a photoresist to be irradiated on a surface of the wafer in the peripheral area, comprising:a means for rotating the wafer; a means for irradiating the peripheral area of the wafer with exposure light; a means for moving the irradiated peripheral area; a means for wafer edge determination by detection of sensor light; a means for moving the means for wafer edge determination in a back and forth direction from a central position of the wafer to a peripheral edge of the wafer; a means for determining the location of the notch in the peripheral edge of the wafer located upstream of the means for wafer edge determination and formed integrally with the means for wafer edge determination; and a controller for detecting sensor light and adapted to control the means for moving the means for edge determination such that the amount of sensor light becomes constant, and which is adapted to control the means for moving the irradiation area such that the irradiation area is moved in the same direction as the direction of motion of the means for wafer edge determination and by the same amount as the amount of motion thereof, wherein the controller is adapted to perform the following steps:prior to exposure of the peripheral area of the wafer and after determining the wafer edge, the wafer is rotated such that the peripheral area of the wafer to be irradiated is moved at least by a distance equal to a distance between the means for wafer edge determination and the means for determining the location of the notch, if, during the rotation of the wafer, an output signal from the means for determining the location of the notch changes from a preset starting signal, irradiation with the exposure light begins, and the position at which the notch starts is determined; when, after the notch start is determined, the peripheral irradiated area reaches the notch start, operation of the means for movement of the peripheral irradiated area is stopped; when, after the notch start is determined, an output signal from the means for determining the location of the notch again changes, the position at which the notch ends is determined and when the peripheral irradiation area reaches the notch end, operation of the means for movement of the peripheral irradiated area is restarted; when, during rotation of the wafer, the output signal from the means for determining the location of the notch does not change, irradiation with exposure light begins after completion of the rotation; and if, prior to the rotation of the wafer, a signal from the means for determining the location of the notch indicates a notch start is present then the position at which the notch starts is determined.