Two-dimensional beam deflector

Abstract

A two dimensional beam deflector is disclosed which deflects beams from multiple optical assemblies. The input of beams of the multiple optical assemblies follow parallel optical paths until deflection to a wafer. An ellipsometer using a two-dimensional beam deflector is also disclosed.

1. A two-dimensional beam deflector for a thickness measuring device for measuring the thickness of films on a sample with a plurality of different optical systems each performing a different measurement technique, the beam deflector comprising:
 two-dimensional translation means for translating said beam deflector along a first scanning axis and along a second scanning axis perpendicular to said first scanning axis;    first deflection means for receiving a plurality of parallel input beams along parallel input axes, said input axes being close to each other and parallel to said first scanning axis, and for deflecting said input beams along a plurality of parallel second axes, said second axes being close to each other and parallel to said second scanning axis;    second deflection means for receiving a plurality of parallel output beams along parallel third axes, said third axes being close to each other and parallel to said second axes, and for deflecting said output beams along a plurality of parallel fourth axes, said fourth axes being close to each other and parallel to said first scanning axis; and    a plurality of optical assemblies, one per input beam, wherein each optical assembly provides its input beam towards said sample, receives its output beam from said sample, processes its input and output beams in accordance with its measurement technique, and provides its output beams along said parallel third axes.    
     
     
       2. A beam deflector according to  claim 1  and wherein said optical assemblies comprises at least an ellipsometric assembly and a spectrophotometric assembly. 
     
     
       3. A thickness measuring device for measuring the thickness of thin films on a sample with two measurement devices, the device comprising:
 first and second stationary illuminators, one for each of said two measurement devices, for providing first and second collimated input light beams along first and second parallel input axes;    a beam deflector for directing said first and second input light beam toward said sample and for directing and collimating corresponding first and second output light beams for said sample, said beam deflector including two-dimensional translation means for translating said beam deflector along a first scanning axis parallel to said input axis, and along a second scanning axis perpendicular to said first scanning axis; and    first and second stationary receivers, one for each of said two measurement devices, for respectively receiving said first and second output light beams along output axes parallel to said input axes.    
     
     
       4. An ellipsometer for measuring the thickness of thin films on a sample comprising:
 a stationary illuminator for providing a collimated input light beam along an input axis;    a beam deflector translatable at least along a first scanning axis parallel to said input axis including: 
 a first beam deflecting element for deflecting said input light beam at a first angle of deflection towards said sample;  
 a second beam deflecting element, different from said first beam deflecting element, for deflecting an output light beam reflected at a second angle from said sample along an output axis; and  
 a collimating lens for receiving at least said output light beam from said second beam deflecting element and for collimating at least said output light beam; and  
 a stationary receiver for receiving said collimated output light beam along an output axis parallel to said input axis.  
   
     
     
       5. A device according to  claim 4  and wherein said beam deflector comprises two-dimensional translation means for translating said beam deflector along said first scanning axis and along a second scanning axis perpendicular to said first scanning axis. 
     
     
       6. A device according to  claim 5  where said beam deflector additionally comprises a first mirror for deflecting said input light beam from said input axis to said second scanning axis, a second mirror for deflecting said input light beam from said second scanning axis to said sample, a third mirror for deflecting a reflected light beam reflected from said sample to said second scanning axis, and a fourth mirror for deflecting said reflected light beam from said second scanning axis to said output axis. 
     
     
       7. An ellipsometer for measuring the thickness of thin films on a sample comprising:
 a stationary illuminator for providing a collimated input light beam along an input axis;    a beam deflector translatable at least along a first scanning axis parallel to said input axis including:    a first beam deflecting element for deflecting said input light beam at a first angle of deflection towards said sample;    a second beam deflecting element, different from said first beam deflecting element, for deflecting an output light beam reflected at a second angle from said sample along an output axis; and    a collimating lens for receiving at least said output light beam from said second beam deflecting element and for collimating at least said output light beam; and    a stationary receiver for receiving said collimated output light beam along an output axis parallel to said input axis,    wherein said beam deflector comprises one-dimensional translation means for translation along said scanning axis.    
     
     
       8. An ellipsometer for measuring the thickness of thin films on a sample comprising:
 a stationary illuminator for providing a collimated input light beam along an input axis;    a beam deflector translatable at least along a first scanning axis parallel to said input axis including:    a first beam deflecting element for deflecting said input light beam at a first angle of deflection towards said sample;    a second beam deflecting element, different from said first beam deflecting element, for deflecting an output light beam reflected at a second angle from said sample along an output axis; and    a collimating lens for receiving at least said output light beam from said second beam deflecting element and for collimating at least said output light beam; and    a stationary receiver for receiving said collimated output light beam along an output axis parallel to said input axis,    wherein said first and second beam deflecting elements are mirrors.    
     
     
       9. An ellipsometer for measuring the thickness of thin films on a sample comprising:
 a stationary illuminator for providing a collimated input light beam along an input axis;    a beam deflector translatable at least along a first scanning axis parallel to said input axis including:    a first beam deflecting element for deflecting said input light beam at a first angle of deflection towards said sample;    a second beam deflecting element, different from said first beam deflecting element, for deflecting an output light beam reflected at a second angle from said sample along an output axis; and    a collimating lens for receiving at least said output light beam from said second beam deflecting element and for collimating at least said output light beam; and    a stationary receiver for receiving said collimated output light beam along an output axis parallel to said input axis,    wherein said first beam deflecting element is a beam splitter and said second beam deflecting element is a mirror.    
     
     
       10. An ellipsometer for measuring the thickness of thin films on a sample comprising:
 a stationary illuminator for providing a collimated input light beam along an input axis;    a beam deflector translatable at least along a first scanning axis parallel to said input axis including:    a first beam deflecting element for deflecting said input light beam at a first angle of deflection towards said sample;    a second beam deflecting element, different from said first beam deflecting element, for deflecting an output light beam reflected at a second angle from said sample along an output axis; and    a collimating lens for receiving at least said output light beam from said second beam deflecting element and for collimating at least said output light beam; and    a stationary receiver for receiving said collimated output light beam along an output axis parallel to said input axis,    and also including means for measuring an actual angle of incidence which may vary from said second angle of deflection, wherein said means for measuring utilizes optical elements forming part of said stationary illuminator and stationary receiver.    
     
     
       11. A device according to  claim 10  and wherein said means for measuring comprises a position sensing device for measuring the angle of said output light beam with respect to a desired position. 
     
     
       12. A processing apparatus for processing a semiconductor sample, the apparatus comprising:
 ( i )  a processing unit comprising several chambers for processing of a top layer of the sample under certain vacuum conditions within a working area inside the processing unit;      ( ii )  an optical monitoring station associated with said processing unit and defining a monitoring area in one of the chambers outside said working area, said one of the chambers having an optical window through which at least a portion of said top layer of the sample is observable from outside of the chamber; and      ( iii )  a robot for transferring said sample from said working area to said monitoring area without breaking the vacuum conditions,        wherein said optical monitoring station comprises an optical monitoring unit, accommodated outside said at least one of the chambers and operable for monitoring at least one desired parameter of at least said top layer of the sample through said optical window, while the sample is located inside said chamber under certain vacuum conditions.     
     
     
       13. A processing apparatus according to  claim 12 , wherein the vacuum- based processing unit comprises deposition equipment.   
     
     
       14. A processing apparatus according to  claim 12 , wherein said vacuum chamber is a part of the processing unit. 
     
     
       15. A processing apparatus according to  claim 14 , wherein said chamber is cool down chamber. 
     
     
       16. A processing apparatus according to  claim 12 , wherein said at least one desired parameter is thickness of said at least top layer of the sample. 
     
     
       17. A processing apparatus according to  claim 12 , wherein said at least one desired parameter is refraction index of said at least top layer of the sample. 
     
     
       18. A processing apparatus according to  claim 12 , wherein said optical monitoring unit is operable to scan at least a portion of the sample through said optical window. 
     
     
       19. A processing apparatus according to  claim 12 , wherein said optical monitoring unit comprises a spectrophotometer. 
     
     
       20. A processing apparatus according to  claim 12 , wherein said optical monitoring unit comprises an ellipsometer. 
     
     
       21. A processing apparatus according to  claim 12 , wherein said optical monitoring unit comprises an imaging unit operable for performing pattern recognition technique such as to determine a measurement site location. 
     
     
       22. A processing apparatus according to  claim 12 , wherein said optical monitoring unit comprises a movable beam deflector. 
     
     
       23. A processing apparatus according to  claim 19  wherein said optical monitoring unit comprises a movable beam deflector and is operable to scan at least a portion of the sample through said optical window. 
     
     
       24. A processing apparatus according to  claim 23 , wherein said optical monitoring unit comprises an objective lens arrangement. 
     
     
       25. A processing apparatus according to  claim 19  wherein said optical monitoring unit comprises an imaging unit operable for performing pattern recognition technique such as to determine a measurement site location. 
     
     
       26. A processing apparatus according to  claim 20 , wherein said one of the chambers has an additional optical window. 
     
     
       27. A processing apparatus according to  claim 12 , wherein said optical monitoring unit comprises a stationary mounted illuminator. 
     
     
       28. A processing apparatus according to  claim 19 , wherein said optical monitoring unit comprises a stationary mounted illuminator. 
     
     
       29. A processing apparatus according to  claim 20 , wherein said optical monitoring unit comprises a stationary mounted illuminator. 
     
     
       30. A processing apparatus according to  claim 19 , wherein said spectrophotometer is stationary mounted. 
     
     
       31. A processing apparatus according to  claim 12 , wherein said vacuum- based processing unit is a cluster tool.   
     
     
       32. A processing apparatus according to  claim 12 , wherein said semiconductor sample is wafer. 
     
     
       33. A processing apparatus according to  claim 12 , wherein said optical monitoring unit is operable to scan at least the portion of the top layer of the sample observable through said optical window, and comprises a beam deflector for directing light towards the sample and directing light from the sample, and a translation means for translating said beam deflector along at least one scanning axis. 
     
     
       34. A cluster tool comprising several chambers for processing a top layer of a semiconductor sample under certain vacuum conditions within a working area of the tool, the cluster tool comprising:
   an optical monitoring station, that defines a monitoring area in one of the chambers outside said working area, said one of the chambers being formed with an optical window through which at least a portion of the top layer of the sample is observable from outside of the chamber, and comprises an optical monitoring unit located outside said one of the chambers and operable for monitoring at least one desired parameter of the sample through said optical window, while the sample is located inside said one of the chambers under certain vacuum conditions; and        a robot for transferring the sample from said working area to said monitoring area without breaking the vacuum conditions.     
     
     
       35. A method for processing a semiconductor sample utilizing a vacuum- based processing unit having several chambers, and an optical monitoring station, the method comprising:    ( a )  processing a top layer of the sample under certain vacuum conditions within a working area inside the processing unit;      ( b )  transferring the sample from the working area to a monitoring area located inside one of the chambers and outside the working area, wherein said one of the chambers is formed with an optical window through which at least a portion of the top layers of the sample is observable from outside of the chamber, said transferring being carried out by a robot without breaking the vacuum conditions; and      ( c )  applying optical monitoring to at least a portion of said sample from the outside of the chamber through said optical window for monitoring at least one desired parameter of the sample, while the sample is located in the monitoring area inside the chamber under certain vacuum conditions.     
     
     
       36. A method according to  claim 35 , wherein said processing of the sample utilizes a deposition technique. 
     
     
       37. A method according to  claim 35 , wherein the sample is conveyed to said monitoring area from the working area after being processed. 
     
     
       38. A method according to  claim 35 , wherein said optical monitoring comprises thickness measurements of at least the top layer of the sample. 
     
     
       39. A method according to  claim 35 , wherein said optical monitoring comprises measurements of refraction index of at least the top layer of the sample. 
     
     
       40. A method according to  claim 35 , wherein said optical monitoring comprises scanning at least a portion of the sample through said optical window. 
     
     
       41. A method according to  claim 35 , wherein said optical monitoring comprises spectrophotometric measurements. 
     
     
       42. A method according to  claim 35 , wherein said optical monitoring comprises ellipsometric measurements. 
     
     
       43. A method according to  claim 35 , wherein said optical monitoring comprises pattern recognition for determining a measurement site location. 
     
     
       44. A method according to  claim 41 , wherein said optical monitoring comprises pattern recognition for determining a measurement site location. 
     
     
       45. A method according to  claim 42 , wherein said optical monitoring comprises pattern recognition for determining a measurement site location. 
     
     
       46. A method according to  claim 41 , wherein said optical monitoring comprises scanning at least a portion of the sample through said optical window. 
     
     
       47. A method according to  claim 42 , wherein said optical monitoring comprises scanning at least a portion of the sample through said optical window. 
     
     
       48. A method according to  claim 35 , wherein said semiconductor sample is a wafer. 
     
     
       49. A method according to  claim 41 , wherein said semiconductor sample is a wafer. 
     
     
       50. A method according to  claim 42 , wherein said semiconductor sample is a wafer.