Patent ID: 11890716
Assignee: EBARA CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 7:
8. A polishing method comprising:
rotating a polishing table to which a polishing pad is attached;
polishing a substrate by flowing a polishing liquid on the polishing pad that polishes the substrate held by a top ring;
detecting a slip out of the substrate from the top ring by emitting a light to a detection area on the polishing pad and receiving the light reflected from the detection area; and
eliminating the polishing liquid flowing into the detection area from an upstream side of the detection area in a direction of rotation of the polishing table,
wherein detecting the slip out of the substrate includes detecting the slip out of the substrate from the top ring based on a difference between a reference color and a color of the light reflected from the detection area of the polishing pad during a polishing process,
wherein detecting the slip out of the substrate further includes:
counting a cumulative number of polishing processes of the substrate;
resetting the reference color by automatically registering the reference color based on the light reflected from the detection area of the polishing pad when the counted cumulative number of polishing processes exceeds a threshold value; and
detecting the slip out of the substrate from the top ring based on a difference between the registered reference color and the color of the light reflected from the detection area of the polishing pad during the polishing process.