Patent ID: 6530822
Filing Date: 2003-03-11
Classification: B24B

Abstract:
A method for controlling polishing time in chemical-mechanical polishing process, comprising:providing a first wafer, said first wafer including a first layer; measuring the thickness of said first layer, the measuring result being a first pre-thickness, the difference between a reference pre-thickness and said first pre-thickness being a first pre-variability; generating a first removal thickness by adding said first pre-variability to a reference removal thickness; dividing said first removal thickness by an initial polishing rate to find a first polishing time, said first layer of said first wafer being treated by chemical-mechanical polishing for the period of said first polishing time; measuring the thickness of said first layer, the measuring result being a first post-thickness, the difference between a target thickness and said first post-thickness being a first post-variability; dividing said first post-variability by said first polishing time, the result then being added to said initial polishing rate to form a first polishing rate; providing a second wafer, said second wafer including a second layer; measuring the thickness of said second layer, the measuring result being a second pre-thickness, the difference between said reference pre-thickness and said second pre-thickness being a second pre-variability; generating a second removal thickness by adding said second pre-variability to said reference removal thickness; dividing said second removal thickness by said first polishing rate to find a second polishing time, said second layer of said second wafer being treated by chemical-mechanical polishing for the period of said second polishing time; measuring the thickness of said second layer, the measuring result being a second post-thickness, the difference between said target thickness and said second post-thickness being a second post-variability; and dividing said second post-variability by said second polishing time, the result then being added to said first polishing rate to form a second polishing rate.