Substrate adsorption method, substrate holding apparatus, substrate polishing apparatus, elastic film, substrate adsorption determination method for substrate holding apparatus, and pressure control method for substrate holding apparatus

A substrate holding apparatus comprising:

• a top ring body;
• an elastic film comprising a first face and a second face opposite the first face, a plurality of areas being formed between the first face and the top ring body, the second face being capable of holding a substrate;
• a first line communicating with a first area among the plurality of areas and capable of pressuring the first area;
• a second line communicating with the first area and capable of exhausting the first area;
• a measurement instrument whose measurement value varies based on a flow volume of the first area;
• a third line communicating with a second area among the plurality of areas and different from the first area, the third line being capable of pressuring or depressurizing the second area;
• and
• a determiner configured to determine whether the substrate is adsorbed to the second face based on the measurement value when the first area is pressured.

A substrate holding apparatus comprising:

• a top ring body provided with a first hole at an outside of a first portion and a second hole at an inside of the first portion;
• an elastic film comprising:
• a first face provided with a second portion capable of being engaged with the first portion, a plurality of areas being formed between the first face and the top ring body;
• and
• a second face opposite the first face, the second face being capable of holding a substrate;
• a first line being capable of pressuring a first area through the first hole positioned at the first area among the plurality of areas;
• a second line capable of depressurizing the first area through the second hole positioned at the first area;
• a measurement instrument whose measurement value varies based on a flow volume of the first area;
• a third line communicating with a second area among the plurality of areas and different from the first area, the third line being capable of pressuring or depressurizing the second area;
• and
• a determiner configured to determine whether the substrate is adsorbed to the second face based on the measurement value when the first area is pressured.