Method for determining position of semiconductor wafer, and apparatus using the same

A method for detecting a notch as a detection site for alignment formed on a peripheral edge of a semiconductor wafer having a protective sheet joined thereto, thereby determining a handling position of the semiconductor wafer, the method comprising:

• a first irradiation step of irradiating the peripheral edge of the semiconductor wafer having the protective sheet joined thereto with light from a light source;
• a light receiving step of detecting the light from the light source through first detection means provided so as to be opposite to the light source with the semiconductor wafer interposed therebetween in a state that the peripheral edge of the semiconductor wafer is irradiated with the light from the light source;
• a center determination step of
• subjecting, to coordinate transformation, the position of the light detected by the first detection means along the peripheral edge of the semiconductor wafer,
• calculating a distance between coordinates of a point determined on a plane of the semiconductor wafer and each coordinates of the peripheral edge of the semiconductor wafer, and
• determining center coordinates based on a variation amount of a collection of the obtained distance data;
• a second irradiation step of irradiating the peripheral edge of the semiconductor wafer with light from a light source;
• a reflection light detection step of detecting light reflected from the semiconductor wafer through an image capturing means in a state that the peripheral edge of the semiconductor wafer is irradiated with the light from an image capturing means by relatively moving a pair of the light source and the first detection means and the semiconductor wafer in such a manner that the pair of the light source and the first detection means rotates about a center axis of the semiconductor wafer;
• and
• a detection site determination step of
• capturing, through the image capturing means, an image of the peripheral edge of the semiconductor wafer irradiated with the light from the light source, and
• comparing predetermined reference image data of the notch with actual image data obtained by the image capturing means, thereby determining a position of the notch formed on the peripheral edge of the semiconductor wafer.

An apparatus for detecting a notch as a detection site for alignment formed on a peripheral edge of a semiconductor wafer having a protective sheet joined thereto, thereby determining a handling position of the semiconductor wafer, the apparatus comprising:

• holding means for holding the semiconductor wafer having the protective sheet joined thereto;
• a light source for irradiating, with light, the peripheral edge of the semiconductor wafer held by the holding means;
• first detection means, provided so as to be opposite to the light source with the semiconductor wafer interposed therebetween, for detecting a position of the light emitted from the light source;
• rotational movement means for allowing a pair of the light source and the first detection means and the holding means to move relatively in such a manner that the pair of the light source and the first detection means moves along the peripheral edge of the semiconductor wafer held by the holding means;
• second detection means for detecting light reflected from the semiconductor wafer among the light emitted from the light source toward the peripheral edge of the semiconductor wafer;
• computation means for
• subjecting, to coordinate transformation, the position of the light in a state that the rotational movement means allows a pair of the light source and light receiving means and the holding means to move relatively,
• calculating a distance between coordinates of a point determined on a plane of the semiconductor wafer and each coordinates of the peripheral edge of the semiconductor wafer,
• determining center coordinates based on a variation amount of a collection of the obtained distance data, and
• obtaining a position of the notch based on a variation in intensity of the reflection light detected by the second detection means;
• and
• control means for controlling the rotational movement means so as to perform alignment of the handling position of the semiconductor wafer held by the holding means in accordance with a result of the computations by the computation means.

An apparatus for detecting a notch as a detection site for alignment formed on a peripheral edge of a semiconductor wafer having a protective sheet joined thereto, thereby determining a handling position of the semiconductor wafer, the apparatus comprising:

• holding means for holding the semiconductor wafer having the protective sheet joined thereto;
• a light source for irradiating, with light, the peripheral edge of the semiconductor wafer held by the holding means;
• first detection means, provided so as to be opposite to the light source with the semiconductor wafer interposed therebetween, for detecting a position of the light emitted from the light source;
• rotational movement means for allowing a pair of the light source and the first detection means and the holding means to move relatively in such a manner that the pair of the light source and the first detection means moves along the peripheral edge of the semiconductor wafer held by the holding means;
• an image capturing means for detecting light reflected from the semiconductor wafer among the light emitted from the light source toward the peripheral edge of the semiconductor wafer;
• computation means of
• subjecting, to coordinate transformation, the position of the light in a state that the rotational movement means allows a pair of the light source and light receiving means and the holding means to move relatively,
• calculating a distance between coordinates of a point determined on a plane of the semiconductor wafer and each coordinates of the peripheral edge of the semiconductor wafer,
• determining center coordinates based on a variation amount of a collection of the obtained distance data, and
• capturing, through the image capturing means, an image of the peripheral edge of the semiconductor wafer irradiated with the light from the light source, and
• comparing predetermined reference image data of the notch with actual image data obtained by the image capturing means, thereby determining a position of the notch formed on the peripheral edge of the semiconductor wafer;
• and
• control means for controlling the rotational movement means so as to perform alignment of the handling position of the semiconductor wafer held by the holding means in accordance with a result of the computations by the computation means.