Polishing apparatus and method of controlling the same

Abstract

A polishing apparatus includes a slurry supply arm arranged on a polish pad for a polishing target and extending from a center of the polish pad into a radius direction; a plurality of nozzles attached to the slurry supply arm to supply the slurry from the plurality of nozzles; and a plurality of pumps, each of which supplies the slurry to one of the plurality of nozzles. A control unit controls each of the plurality of pumps independently.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing the configuration of a polishing apparatus of the present invention;

FIG. 2 is a front view showing the configuration of the polishing apparatus of the present invention;

FIGS. 3A to 3C are diagrams showing experimental results under different conditions that the slurry flow amount is independently controlled;

FIG. 4 is a diagram showing experiment results of relation between the polishing rates (nm/min) of the wafers polished under the slurry flow amounts in cases 1 to 3 of FIGS. 3A to 3C and a distances from the wafer center

FIG. 5 is a flowchart showing an operation of the polishing apparatus;

FIG. 6A is a diagram showing the calculation results;

FIG. 6B is a diagram showing calculation equations used in steps S30 to S70;

FIG. 7 is a graph showing a relation between a slurry flow amount and a division result (R/A ratio); and

FIG. 8 is a diagram showing a polishing recipe.

Claims

1. A polishing apparatus comprising: a slurry supply arm arranged on a polish pad for a polishing target and extending from a center of said polish pad into a radius direction;a plurality of nozzles attached to said slurry supply arm to supply said slurry from said plurality of nozzles;a plurality of pumps, each of which supplies said slurry to one of said plurality of nozzles; anda control unit configured to control each of said plurality of pumps independently.

2. The polishing apparatus according to claim 1, further comprising: a thickness measuring section connected with said control unit to measure thicknesses of said polishing target,wherein said control unit controls said plurality of pumps based on the measured thicknesses.

3. The polishing apparatus according to claim 2, wherein said thickness measuring section measures the thicknesses of said polishing target before and after said polishing in a position corresponding to each of said plurality of nozzles, and said control unit calculates a polishing amount on the position corresponding to each of said plurality of nozzles from the thicknesses of said polishing target before and after the polishing, and controls each of said plurality of pumps based on a corresponding one of said polishing amounts.

4. The polishing apparatus according to claim 3, wherein said control unit divides each of said polishing amounts on the positions corresponding to said plurality of nozzles by an average of said polishing amounts, controls one of said plurality of pumps corresponding to said polishing amount such that a flow rate of said slurry is increased, when a division result is smaller than one, and controls one of said plurality of pumps corresponding to said polishing amount such that a flow rate of said slurry is decreased, when the division result is larger than one.

5. The polishing apparatus according to claim 4, wherein said control unit performs the division by using a moving average value instead of said average of said polishing amounts when a plurality of said polishing targets are polished in order.

6. A control method of a polishing apparatus, comprising: providing a polishing apparatus having a plurality of nozzles configured to supply slurry from each of said plurality of nozzles, and a plurality of pumps configured to supply said slurries to said plurality of nozzles; andcontrolling each of said plurality of pumps independently such that a polishing target is polished.

7. The control method according to claim 6, further comprising: measuring initial thicknesses of said polishing target in positions corresponding to said plurality of nozzles; andmeasuring post-polishing thicknesses of said polishing target after polishing in positions corresponding to said plurality of nozzles,wherein said controlling comprises:controlling flow rates of said slurries supplied by said plurality of pumps based on said thicknesses of said polishing target before and after said polishing in the positions corresponding to said plurality of nozzles.

8. The control method according to claim 6, further comprising: measuring initial thicknesses of said polishing target in positions corresponding to said plurality of nozzles; andmeasuring post-polishing thicknesses of said polishing target after polishing in positions corresponding to said plurality of nozzles,wherein said controlling comprises:calculating a polishing amount on each of the positions corresponding to said plurality of nozzles from the thicknesses of said polishing target before and after said polishing; anddetermining flow rates of said slurries supplied by said plurality of pumps based on said polishing amounts.

9. The control method according to claim 8, wherein said controlling comprises: dividing each of said polishing amounts on the positions corresponding to said plurality of nozzles by an average of said polishing amounts,said determining comprises:determining said flow rate of said slurry from one of said plurality of pumps corresponding to said polishing amount such that said flow rate of said slurry is increased, when a division result is smaller than one; anddetermining said flow rate of said slurry from said one pump such that said flow rate of said slurry is decreased, when the division result is larger than one.

10. The control method according to claim 9, further comprising: polishing a plurality of said polishing targets in order under a same condition,wherein said controlling is performed each time each of said plurality of polishing targets is polished,a moving average value of said polishing targets which have been already polished is used in said determining instead of said average of said polishing amounts.