Polishing method and polishing apparatus
A polishing method and a polishing apparatus which can increase a polishing rate and can control a polishing profile of a substrate being polished by adjusting a surface temperature of a polishing pad are disclosed. The polishing method for polishing a substrate by pressing the substrate against a polishing pad on a polishing table includes a pad temperature adjustment step of adjusting a surface temperature of the polishing pad, and a polishing step of polishing the substrate by pressing the substrate against the polishing pad having the adjusted surface temperature. In the pad temperature adjustment step, the surface temperature of a part of an area of the polishing pad, the area being to be brought in contact with the substrate, is adjusted during the polishing step so that the rate of temperature change of a temperature profile in a radial direction of the surface of the polishing pad becomes constant in the radial direction of the polishing pad.
1. A polishing apparatus for polishing a substrate by pressing the substrate against a polishing pad on a polishing table, comprising:
a top ring configured to press the substrate against the polishing pad on the polishing table;
a pad contact member configured to be brought in contact with the surface of the polishing pad to heat or cool the polishing pad; and
a liquid supply system comprising a liquid supply tank having a heater therein, a heated water supply line having a first valve configured to supply heated water from the liquid supply tank to the pad contact member, a return line having a second valve configured to return the heated water from the pad contact member to the liquid supply tank, a cold water supply line having a third valve configured to supply cold water to the pad contact member, and a discharge line having a fourth valve configured to discharge the heated water or the cold water from the pad contact member to the outside of the liquid supply system;
wherein when the liquid to be supplied to the pad contact member is switched between the heated water and the cold water, the valve switching is performed with an appropriate delay so that the cold water is supplied to the pad contact member after returning the heated water, remaining in the pad contact member and piping, to the liquid supply system or the heated water is supplied to the pad contact member after discharging the cold water remaining in the pad contact member and piping.
2. The polishing apparatus according to claim 1 , wherein a partition is provided in an interior of the pad contact member to form a plurality of passages which have an inlet and an outlet, respectively and are configured to allow the heated water or the cold water to flow individually.
3. The polishing apparatus according to claim 1 , further comprising:
a thermometer configured to measure a surface temperature of the polishing pad; and
a temperature controller configured to control the surface temperature of the polishing pad based on a measured surface temperature measured by the thermometer;
wherein the temperature controller controls switching of the first to fourth valves to start supply of the heated water or the cold water to the pad contact member, based on a comparison result between a preset temperature of the polishing pad and the measured surface temperature measured by the thermometer.
4. The polishing apparatus according to claim 3 , wherein an upper control limit and a lower control limit are set on the preset temperature; and
the temperature controller controls switching of the first to fourth valves to start supply of the heated water or the cold water to the pad contact member when the measured surface temperature reaches the upper control limit or the lower control limit.
5. The polishing apparatus according to claim 1 , further comprising:
a circulating line having a fifth valve configured to circulate the heated water such that the heated water flows out from the liquid supply tank, flows through the circulating line, and flows into the liquid supply tank.