| CPC H01L 21/68707 (2013.01) [B25J 15/0014 (2013.01); B25J 19/025 (2013.01); H01L 21/67265 (2013.01); H01L 21/67766 (2013.01); H01L 21/681 (2013.01)] | 11 Claims |

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1. A substrate transfer apparatus comprising:
a base;
a robot arm mounted on the base;
an end effector provided at a tip of the robot arm and having a first tip portion and a second tip portion that are bifurcated;
a light emitting unit configured to emit light from the first tip portion toward the second tip portion;
a light receiving unit configured to convert detection light into an output value continuously changed depending on an amount of received light traveling through a space between the first tip portion and the second tip portion and incident on the second tip portion; and
a control device controlling an operation of the robot arm,
wherein the control device
controls an operation of the robot arm so that light traveling through a tip of the end effector scans edges of a plurality of substrates accommodated in a front opening unified pod (FOUP), and
compares shape patterns of a measured waveform of the output value continuously changed in the light receiving unit with shape patterns of a reference waveform for comparison according to a relative positional relationship between the light and the substrate during the operation of the robot arm and diagnoses at least one of a state of the substrate, a state of the FOUP, and a state of the end effector based on a comparison result.
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