Apparatus for endpoint detection during polishing

Abstract

An apparatus for endpoint detection during polish, being used to monitor the surface polishing status of a polishing surface of a workpiece, is disclosed, which comprises: a probe, being positioned above the workpiece by a height; and at least a sensing element, being disposed on the probe at a position corresponding to the polishing surface, capable of sensing the thickness variation of the workpiece during a polishing process as it is performing a surface dynamic scan upon the workpiece in rotating while it is being driven to proceed a linear motion of displacement. Preferably, the sensing element can be a device selected from the group consisting of an optical sensor, an eddy current sensor and the combination of the two for carrying out optical detection and magnetic flux detection. It is noted that the apparatus for endpoint detection of the invention not only is advantaged in its all-zone detection ability, but also it has enhanced detection accuracy with respect to different metal layer of different thickness.

1 . An apparatus of endpoint detection during a polishing process, being used to monitor the surface polishing status of a polishing surface of a workpiece, comprising: 
 a probe, being positioned above the workpiece by a height; and    at least a sensing element, being disposed on the probe at a position corresponding to the polishing surface, capable of sensing the thickness variation of the workpiece during the polishing process while it is being driven to proceed a linear motion of displacement.    
   
   
       2 . The apparatus of  claim 1 , wherein the sensing element further comprises an inductor, capable of generating a magnetic filed on the workpiece for inducing eddy currents to be generated on the workpiece.  
   
   
       3 . The apparatus of  claim 2 , wherein the sensing element further comprises an eddy current sensor for detecting the intensity of the magnetic field generated on the workpiece.  
   
   
       4 . The apparatus of  claim 3 , wherein the sensing element further comprises a light source for emitting a light beam onto the workpiece.  
   
   
       5 . The apparatus of  claim 4 , further comprising at least an optic sensor, for receiving light beams reflected from the workpiece.  
   
   
       6 . The apparatus of  claim 5 , wherein each optic sensor is being disposed on a linear rail for enabling the same to be driven to proceed a linear motion of displacement so as to receive the plural light beams reflected from the workpiece.  
   
   
       7 . The apparatus of  claim 2 , wherein the workpiece is made of a metal.  
   
   
       8 . The apparatus of  claim 1 , wherein the sensing element further comprises a light source for emitting a light beam onto the workpiece.  
   
   
       9 . The apparatus of  claim 8 , wherein further comprising at least an optic sensor, for receiving light beams reflected from the workpiece  
   
   
       10 . The apparatus of  claim 9 , wherein each optic sensor is being disposed on a linear rail for enabling the same to be driven to proceed a linear motion of displacement so as to receive the plural light beams reflected from the workpiece.  
   
   
       11 . The apparatus of  claim 1 , wherein the sensing element is being disposed on a linear rail while the linear rail is arranged in the probe.  
   
   
       12 . The apparatus of  claim 1 , further comprising a signal integrating unit, electrically connected to the sensing element, for integrating signals received from the sensing element to output a sensing signal.  
   
   
       13 . The apparatus of  claim 12 , wherein the signal integrating unit is further coupled to a control unit for enabling the control unit to evaluate the surface polishing status of the workpiece basing on the sensing signal.