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 method for determining a temperature adjustment area of a polishing pad, for use in a polishing method for polishing a substrate by pressing the substrate against the polishing pad on a polishing table, comprising:
a first step of defining a plurality of concentric annular areas in a radial direction of the polishing pad, selecting the area to adjust the surface temperature from the defined plural areas, adjusting the surface temperature of the selected area to a predetermined temperature, calculating, for each of radial positions on the substrate, an amount of heat that the substrate receives from the polishing pad by contact with the temperature-adjusted polishing pad, calculating, for each of the radial positions on the substrate, an integrated value of the amount of heat during rotation of the substrate from the calculated amount of heat, thereby obtaining a profile of the integrated value of the amount of heat in the radial direction of the substrate, and preparing and accumulating, for each area to adjust the surface temperature, the profile of the integrated value of the amount of heat;
a second step of obtaining a temperature profile in the radial direction of the surface of the polishing pad when the substrate is polished under such polishing conditions as to achieve a target polishing profile in a state where the surface temperature of the polishing pad is not adjusted, and calculating, for each of radial positions on the substrate, an integrated value of the amount of heat during rotation of the substrate from the temperature profile, thereby obtaining a profile of the integrated value of the amount of heat in the radial direction of the substrate; and
a third step of selecting a profile which is equal or similar to a profile of the integrated value of the amount of heat, obtained by normalizing the profile of the integrated value of the amount of heat obtained in the second step, from profiles of the integrated value of the amount of heat, obtained by normalizing the profiles of the integrated value of the amount of heat accumulated in the first step;
wherein an area where the surface temperature of the polishing pad is adjusted is determined based on the profile selected in the third step.
2. The method for determining a temperature adjustment area of a polishing pad according to claim 1 , wherein there are a plurality of areas where the surface temperature of the polishing pad is adjusted, and the plurality of areas have difference temperatures from each other.
3. A polishing method for polishing a substrate by pressing the substrate against a polishing pad on a polishing table, comprising:
a first step of defining a plurality of concentric annular areas in a radial direction of the polishing pad, selecting the area to adjust the surface temperature from the defined plural areas, adjusting the surface temperature of the selected area to a predetermined temperature, calculating, for each of radial positions on the substrate, an amount of heat that the substrate receives from the polishing pad by contact with the temperature-adjusted polishing pad, calculating, for each of the radial positions on the substrate, an integrated value of the amount of heat during rotation of the substrate from the calculated amount of heat, thereby obtaining a profile of the integrated value of the amount of heat in the radial direction of the substrate, and preparing and accumulating, for each area to adjust the surface temperature, the profile of the integrated value of the amount of heat;
a second step of obtaining a temperature profile in the radial direction of the surface of the polishing pad when the substrate is polished under such polishing conditions as to achieve a target polishing profile in a state where the surface temperature of the polishing pad is not adjusted, and calculating, for each of radial positions on the substrate, an integrated value of the amount of heat during rotation of the substrate from the temperature profile, thereby obtaining a profile of the integrated value of the amount of heat in the radial direction of the substrate;
a third step of selecting a profile which is equal or similar to a profile of the integrated value of the amount of heat, obtained by normalizing the profile of the integrated value of the amount of heat obtained in the second step, from profiles of the integrated value of the amount of heat, obtained by normalizing the profiles of the integrated value of the amount of heat accumulated in the first step; and
a fourth step of determining an area where the surface temperature of the polishing pad is adjusted based on the profile selected in the third step, and polishing the substrate by pressing the substrate against the polishing pad while adjusting the surface temperature of the determined area of the polishing pad.
4. The polishing method according to claim 3 , wherein there are a plurality of areas where the surface temperature of the polishing pad is adjusted, and the plurality of areas have difference temperatures from each other.
5. The polishing method according to claim 3 , wherein the temperature profile in the radial direction of the surface of the polishing pad is prepared during the polishing of the substrate.
6. The polishing method according to claim 5 , wherein the temperature profile in the radial direction of the surface of the polishing pad is a temperature distribution in the radial direction of the surface of the polishing pad.
7. The polishing method according to claim 5 , wherein the rate of temperature change of the temperature profile in the radial direction of the surface of the polishing pad is calculated for each of temperature measurement points on the polishing pad.
8. The polishing method according to claim 7 , wherein the area of the polishing pad whose surface temperature is adjusted is variable depending on the rate of temperature change during the polishing of the substrate.
9. The polishing method according to claim 3 , wherein the temperature measurement of the polishing pad is performed by a thermograph or a radiation thermometer.