Polishing end point detection method, polishing end point detection apparatus and polishing apparatus

An apparatus for detecting a polishing end point of a workpiece having an upper layer and an underlying lower layer, said apparatus comprising:

• a light emitter configured to emit a first light and a second light to a surface of the workpiece at a first angle of incidence and a second angle of incidence, respectively;
• a light receiver configured to receive the first light and the second light reflected from the surface;
• a polarizing filter located between the surface of the workpiece and said light receiver;
• and
• a processing section configured to perform a first analyzing process of analyzing a brightness and a saturation of the surface from the first light received by said light receiver and to perform a second analyzing process of analyzing a brightness and a saturation of the surface from the second light received by said light receiver,
• said processing section being configured to determine removal of the upper layer based on changes in the brightness and the saturation of the surface.

An apparatus for polishing a workpiece having an upper layer and an underlying lower layer, said apparatus comprising:

• a polishing table configured to support a polishing pad having the polishing surface and a through-hole;
• a top ring configured to press the workpiece against the polishing surface of the polishing pad;
• and
• a polishing end point detection unit,
• said polishing end point detection unit including
• (i) a light emitter configured to emit a first light and a second light through the through-hole to a surface of the workpiece at a first angle of incidence and a second angle of incidence, respectively,
• (ii) a light receiver configured to receive the first light and the second light reflected from the surface,
• (iii) a polarizing filter located between the surface of the workpiece and said light receiver, and
• (iv) a processing section configured to perform a first analyzing process of analyzing a brightness and a saturation of the surface from the first light received and to perform a second analyzing process of analyzing a brightness and a saturation of the surface from the second light received,
• wherein said processing section is configured to determine removal of the upper layer based on changes in the brightness and the saturation of the surface.

A method of detecting a polishing end point of a workpiece, said method comprising:

• emitting a light to a surface of the workpiece;
• receiving the light reflected from the surface of the workpiece;
• obtaining a phase difference Δ between p-polarized light and s-polarized light contained in the reflected light and an amplitude ratio ψ of the p-polarized light to the s-polarized light;
• plotting coordinates, specified by the amplitude ratio ψ and the phase difference Δ, on a coordinate system having coordinate axes representing the amplitude ratio ψ and the phase difference Δ;
• and
• determining the polishing end point based on a change in track of the coordinates plotted on the coordinate system.

A method of detecting a polishing end point of a workpiece, said method comprising;

• emitting a light to a surface of the workpiece;
• receiving the light reflected from the surface of the workpiece;
• obtaining a phase difference Δ between p-polarized light and s-polarized light contained in the reflected light;
• plotting coordinates, specified by a polishing time t and the phase difference Δ, on a coordinate system having coordinate axes representing the polishing time t and the phase difference Δ;
• and
• determining the polishing end point based on a change in track of the coordinates plotted on the coordinate system.

A method of detecting a polishing end point of a workpiece, said method comprising:

• emitting a light to a surface of the workpiece;
• receiving the light reflected from the surface of the workpiece;
• obtaining an amplitude ratio ψ of p-polarized light to s-polarized light contained in the reflected light;
• plotting coordinates, specified by a polishing time t and the amplitude ratio ψ, onto a coordinate system having coordinate axes representing the polishing time t and the amplitude ratio ψ;
• and
• determining the polishing end point based on a change in track of the coordinates plotted on the coordinate system.

An apparatus for polishing a workpiece by providing relative motion between the workpiece and a polishing surface, said apparatus comprising:

• a polishing table configured to support a polishing pad having the polishing surface and a through-hole, an upper end of the through-hole lying in the polishing surface;
• a top ring configured to press the workpiece against the polishing surface of the polishing pad;
• a light emitter configured to emit a light to a surface of the workpiece through the through-hole;
• a light receiver configured to receive the light from the workpiece;
• a calculating section configured to obtain a phase difference Δ between p-polarized light and s-polarized light contained in the reflected light and an amplitude ratio ψ of the p-polarized light to the s-polarized light;
• a determining section configured to plot coordinates, specified by the amplitude ratio ψ and the phase difference Δ, on a coordinate system having coordinate axes representing the amplitude ratio ψ and the phase difference Δ and to determine a polishing end point based on a change in track of the coordinates plotted on the coordinate system;
• and
• a controller configured to control polishing of the workpiece.