Chuck table and manufacturing method of chuck table

A grinding machine comprising:

• a chuck table that holds a wafer;
• a grinding unit that includes a grinding wheel for rotation with a plurality of grinding stones disposed in an annular pattern thereon to grind the wafer held on the chuck table;
• and
• a grinding water supply unit that supplies grinding water to the grinding stones and the wafer,
• wherein the chuck table includes a holding plate having a holding surface that holds the wafer thereon under suction, and a frame body that transmits a negative pressure or a positive pressure to the holding surface, and
• wherein the holding plate is formed such that a plurality of cleaved portions are included through cleavage of the holding plate into a plurality of blocks along a plurality of modified layers formed by applying a laser beam of a wavelength, which has transmissivity through the holding plate, with a focal point thereof positioned inside the holding plate, and the negative pressure or the positive pressure is transmitted from the cleaved portions to the holding surface, wherein a width of each of the plurality of blocks is at least twice as large as a width of each of the plurality of cleaved portions, and
• wherein an air and water supply source is connected to the frame body via a communication passage, such that operating the air and water supply source supplies a mixed fluid of air and water to a porous plate of the frame body.

A manufacturing method of a chuck table including a holding surface that holds a wafer thereon, comprising:

• a base material providing step of providing a base material for a holding plate;
• a modified layer forming step of forming a plurality of modified layers by applying a laser beam of a wavelength, which has transmissivity through the base material, with a focal point thereof positioned inside the base material,
• a cleaving step of forming a plurality of cleaved portions by cleaving the base material into a plurality of blocks along the modified layers by applying an external force to the base material, and
• an integration step of integrating the holding plate, in which the cleaved portions have been formed, with a frame body that supports the holding plate thereon,
• wherein an air and water supply source is connected to the frame body via a communication passage, such that operating the air and water supply source supplies a mixed fluid of air and water to a porous plate of the frame body.