Polishing pad, polishing apparatus, and polishing method

A polishing apparatus for polishing a substrate, comprising:

• a polishing-pad structure;
• a polishing table configured to support the polishing-pad structure;
• a polishing head configured to press the substrate against the polishing-pad structure;
• and
• a light source configured to emit light to the polishing-pad structure,
• wherein the polishing-pad structure includes a polishing pad having a polishing surface for polishing the substrate,
• at least a part of the polishing-pad structure is made of a light transmissive material and a light reactive material, the light reactive material being mixed into the light transmissive material, and
• the polishing-pad structure further includes a light reactive sheet configured to change its physical property in response to light, and
• at least a part of the light reactive sheet is made of the light transmissive material and the light reactive material.

A polishing method comprising:

• setting a wavelength of light, an intensity of light, or an irradiation time of light to an initial set value, and directing the light, emitted by a light source, to a polishing-pad structure having a polishing pad for polishing a substrate, at least a part of the polishing-pad structure being made of a light transmissive material and a light reactive material, the light reactive material being mixed into the light transmissive material, the polishing-pad structure being supported by a polishing table;
• pressing the substrate by a polishing head against a polishing surface of the polishing pad while independently rotating the polishing head and the polishing table to polish the substrate;
• measuring a physical quantity indirectly indicating a rigidity of the polishing pad after termination of the polishing;
• calculating a difference between a target value of the physical quantity and a measured value of the physical quantity;
• comparing the difference with a predefined physical-quantity reference range;
• when the difference is out of the physical-quantity reference range, calculating an optimum value of the wavelength of the light, the intensity of the light, or the irradiation time of the light based on a correlation between the physical quantity and one of the wavelength of the light, the intensity of the light, and the irradiation time of the light, and changing the wavelength of the light, the intensity of the light, or the irradiation time of the light to the optimum value;
• and
• when the physical quantity is within the physical-quantity reference range, polishing the substrate,
• wherein the target value of the physical quantity is a value of the physical quantity when the light is directed to the polishing-pad structure under a condition that the wavelength of the light, the intensity of the light, or the irradiation time of the light has the initial set value.