Chemical mechanical polishing apparatus and method of manufacturing semiconductor device

Abstract

A chemical mechanical polishing apparatus includes a polishing head, including a polishing head body, a membrane attached to a lower portion of the polishing head body, and a reflector disposed between the polishing head body and the membrane, a platen including an opening, an emitter disposed below the opening of the platen, the emitter configured to emit terahertz waves, a detector disposed below the opening of the platen, the detector configured to receive the terahertz waves emitted by the emitter and reflected by the reflector, and an analyzer configured to analyze an electrical signal generated by converting the terahertz waves received by the detector, the analyzer configured to determine a polishing end point.

What is claimed is: 
     
         1 . A chemical mechanical polishing apparatus, comprising:
 a polishing head, including a polishing head body, a membrane attached to a lower portion of the polishing head body, and a reflector disposed between the polishing head body and the membrane;   a platen including an opening;   an emitter disposed below the opening of the platen, the emitter configured to emit terahertz waves;   a detector disposed below the opening of the platen, the detector configured to receive the terahertz waves emitted by the emitter and reflected from the reflector; and   an analyzer configured to analyze an electrical signal generated by converting the terahertz waves received by the detector, the analyzer configured to determine a polishing end point.   
     
     
         2 . The chemical mechanical polishing apparatus of  claim 1 , wherein the reflector includes a plurality of reflecting regions in the form of rings. 
     
     
         3 . The chemical mechanical polishing apparatus of  claim 2 , wherein the plurality of reflecting regions are spaced apart from each other. 
     
     
         4 . The chemical mechanical polishing apparatus of  claim 2 , wherein the plurality of reflecting regions have the same width in a radial direction. 
     
     
         5 . The chemical mechanical polishing apparatus of  claim 2 , wherein one region of the plurality of reflecting regions has a first width in a radial direction, another region of the plurality of reflecting regions has a second width in the radial direction, and the first and second widths are different from each other. 
     
     
         6 . The chemical mechanical polishing apparatus of  claim 2 , wherein the polishing head further includes a membrane clamp disposed in a lower portion of the polishing head body and to which the membrane is fixed, and
 wherein the reflector is coupled to the membrane clamp, and is disposed between the membrane clamp and the membrane.   
     
     
         7 . The chemical mechanical polishing apparatus of  claim 6 , wherein the reflector includes a support and a metal layer coated on a surface of the support, and
 the support is in contact with the membrane clamp.   
     
     
         8 . The chemical mechanical polishing apparatus of  claim 7 , wherein the metal layer comprises gold, silver, aluminum, or a combination thereof. 
     
     
         9 . The chemical mechanical polishing apparatus of  claim 1 , wherein the detector is configured to convert the terahertz waves, passing through a substrate being polished and then reflected by the reflector, into an electrical signal having a time domain waveform, and
 wherein the analyzer is configured to compare a time delay value having a maximum amplitude of the electrical signal, transmitted by the detector, with a preset target time delay value, to determine the polishing end point.   
     
     
         10 . The chemical mechanical polishing apparatus of  claim 1 , wherein the emitter and the detector are coupled to the platen and are configured to rotate together with the platen. 
     
     
         11 . A chemical mechanical polishing apparatus, comprising:
 a platen including an opening;   a polishing head disposed on the platen and configured to support a substrate;   an emitter disposed below the opening, the emitter configured to irradiate the substrate with terahertz waves; and   a detector disposed adjacent to the emitter, the detector configured to receive the terahertz waves passing through the substrate,   wherein the polishing head includes a reflector configured to reflect the terahertz waves passing through the substrate.   
     
     
         12 . The chemical mechanical polishing apparatus of  claim 11 , wherein the reflector includes a plurality of reflecting regions in the form of rings, the plurality of reflecting regions spaced apart from each other. 
     
     
         13 . The chemical mechanical polishing apparatus of  claim 11 , wherein the polishing head further includes a membrane configured to support the substrate and a membrane clamp to which the membrane is fixed, and
 the reflector is coupled to the membrane clamp, and is disposed between the membrane clamp and the membrane.   
     
     
         14 . The chemical mechanical polishing apparatus of  claim 13 , wherein the reflector includes a support coupled to the membrane clamp and a metal layer coated on the support, and the metal layer comprises gold, silver, aluminum, or a combination thereof. 
     
     
         15 . The chemical mechanical polishing apparatus of  claim 13 , wherein a lower surface of the membrane clamp includes a plurality of regions in the form of rings, spaced apart from each other. 
     
     
         16 . The chemical mechanical polishing apparatus of  claim 11 , further comprising an analyzer configured to analyze the terahertz waves received by the detector, the analyzer configured to determine a polishing end point. 
     
     
         17 . A chemical mechanical polishing apparatus, comprising:
 a polishing head including a reflector, the polishing head configured to support a substrate;   an emitter disposed below the polishing head, the emitter configured to irradiate the substrate with terahertz waves; and   a detector disposed adjacent to the emitter, the detector configured to receive the terahertz waves passing through the substrate and then reflected by the reflector.   
     
     
         18 . The chemical mechanical polishing apparatus of  claim 17 , wherein the reflector includes a plurality of reflecting regions in the form of rings spaced apart from each other. 
     
     
         19 . The chemical mechanical polishing apparatus of  claim 17 , wherein the reflector includes a metal layer comprising gold, silver, aluminum, or a combination thereof. 
     
     
         20 . The chemical mechanical polishing apparatus of  claim 17 , wherein the polishing head further includes a membrane configured to support the substrate and a membrane clamp to which the membrane is fixed, and
 wherein the reflector is coupled to the membrane clamp, and is disposed between the membrane clamp and the membrane.