Patent ID: 11883837
Assignee: TOKYO ELECTRON LIMITED
Field: Measurement (Instruments)
Classification: CPC B  G  H | IPC B  G  H

Claim 8:
9. A system for dispensing liquid on a substrate, the system comprising:
a substrate holder configured to hold a substrate and rotate the substrate about an axis;
a dispense unit configured to dispense a liquid on a working surface of the substrate while the substrate is being rotated on the substrate holder;
a laser configured to direct a laser beam at an edge location on the working surface of the substrate;
a first detector positioned to capture scattered light from the laser beam directed at the edge location of the substrate;
a second detector positioned to capture reflected light from the laser beam directed at the edge location of the substrate;
a processor configured to monitor scattered light and reflected light from the laser beam directed at the edge location on the substrate to identify a pattern of scattered light and a pattern of reflected light, respectively, indicating that the liquid has reached the edge location on the substrate; and
the processor further configured to identify an actual coating time of the liquid beginning from initiation of a given dispense of the liquid onto the working surface until the liquid reaches the edge location of the working surface, and compare the actual coating time of the liquid to an expected coating time of the liquid.