APPARATUS FOR OPTICAL INSPECTION OF WAFERS DURING PROCESSING

• US 20050164608A2
• Filed: 06/04/2004
• Published: 07/28/2005
• Est. Priority Date: 05/23/1995
• Status: Active Grant

• Current Assignee: Explay Ltd., Nova Ltd.
• Original Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Inventors: Finarov, Moshe
• Granted Patent: US 7,169,015 B2
• Time in Patent Office: Days
• US Class Current: 451/6
• CPC Class Codes: B24B 37/345 Feeding, loading or unloading work specially adapted to lapping
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices

Abstract

Abstract of the Disclosure

An optical system is disclosed for the inspection of wafers during polishing which also includes a measurement system for measuring the thickness of the wafers top layer. The optical system views the wafer through a window and includes a gripping system, which places the wafer in a predetermined viewing location while maintaining the patterned surface completely under water. The optical system also includes a pull-down unit for pulling the measurement system slightly below the horizontal prior to the measurement and returns the measuring system to the horizontal afterwards

Claims

1. A measurement station for use with a processing machine, which includes a processing station for processing an article and an exit station including an article transfer assembly and at least one articles’

cassette, the measurement station being so dimensioned as to be installable in association with the exit station of the processing machine and comprising an optical system and a holding unit for receiving and holding the article in a measuring position during measurements, said optical system comprising;

a spectrophotometer;

an imaging system operable to locate measurements;

a beam directing assembly for directing illuminating light towards the article and directing collected light from the article towards a beam splitting assembly for separating a first portion of the collected light to propagate towards the spectrophotometer and a second portion to propagate to said imaging system.

2. The measurement station according to Claim 1, wherein said beam splitting assembly comprising an inclined mirror surface.

3. The measurement station according to Claim 1, wherein said beam splitting assembly comprising a pin hole mirror.

4. The processing machine according to Claim 1, wherein said imaging system comprises a charge coupled device (CCD).

5. The measurement station according to Claim 1, wherein said optical system is configured and operable to enable measuring a thickness of at least a top layer of the article.

6. The measurement station according to Claim 1, wherein said optical system is configured and operable to carry out optical inspection of the processed article.

7. The measurement station according to Claim 1, comprising a support assembly for supporting the article.

8. The measurement station according to Claim 7, wherein said support assembly is configured for supporting the article that is to be received from the holding unit.

9. The measurement station according to Claim 7, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

10. The measurement station according to Claim 8, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

11. The measurement station according to Claim 1, wherein the optical system and the holding unit are separated by a window through which at least a part of the article being held is viewable to enable optical measurements.

12. The measurement station according to Claim 1, wherein said holding unit comprises an assembly movable along an axis perpendicular to the article’

s surface, thereby enabling said holding of the article in the measuring position.

13. The measurement station according to Claim 1, having a footprint in at least one dimension of about a size of the article’

s diameter.

14. The measurement station according to Claim 1, wherein said processing machine is a polisher.

15. The measurement station according to Claim 1, configured for receiving the processed article from the processing machine via said article transfer assembly of the exit station.

16. The measurement station according to Claim 1, wherein said optical system includes a focusing optics for focusing the illuminated light onto the article and collecting the light from the illuminated article.

17. The measurement station according to Claim 7, wherein the support assembly is configured to receive the article from the article transfer assembly of the exit station and to enable the article transfer into the measuring position.

18. The measurement station according to Claim 7, wherein the support assembly includes two support elements displaceable with respect to each other.

19. The measurement station according to Claim 7, wherein the support assembly is configured for supporting the article at its periphery region.

20. The measurement station according to Claim 1, wherein the imaging system is operable to perform pattern recognition.

21. The measurement station according to Claim 16, wherein the optical system comprises a fiber optics for directing light from a light source towards the focusing optics.

22. The measurement station according to Claim 16, wherein the focusing optics comprises an objective lens arrangement.

23. The measurement station according to Claim 1, wherein the imaging system includes a lens arrangement accommodated between an imaging detector and the beam splitting assembly.

24. The measurement station according to Claim 1, wherein the optical system comprises a lens arrangement accommodated between the beam splitting assembly and the spectrophotometer.

25. The measurement station according to claim 1, wherein the optical system is configured for providing substantially normal incidence of the illuminating light.

26. The measurement station according to Claim 3, wherein the pin hole mirror is accommodated so as to be an aperture stop in an optical path of the collected light, the pin hole mirror thereby appearing as a dark area in an image of a measurement spot on the article and allowing for locating the measurement spot.

27. The measurement station according to Claim 1, wherein the holding unit comprises a vacuum assembly for holding the article by vacuum.

28. The measurement station according to Claim 17, wherein the support assembly includes two support elements displaceable with respect to each other.

29. The measurement station according to Claim 1, configured to be installable within the exit station of the processing machine.

30. The measurement station according to Claim 1, wherein said optical system is configured and operable to measure in the patterned article.

31. The measurement station according to Claim 2, wherein said inclined mirror surface is a surface of a pin hole mirror.

32. The processing machine according to Claim 2, wherein said imaging system comprises a charge coupled device (CCD).

33. The measurement station according to Claim 2, wherein said optical system is operable to measure a thickness of at least a top layer of the article.

34. The measurement station according to Claim 2, wherein said optical system is operable to carry out optical inspection of the processed article.

35. The measurement station according to Claim 2, comprising a support assembly for supporting the article.

36. The measurement station according to Claim 35, wherein said support assembly is configured for supporting the article that is to be received from the holding unit.

37. The measurement station according to Claim 35, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

38. The measurement station according to Claim 36, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

39. The measurement station according to Claim 2, wherein the optical system and the holding unit are separated by a window through which at least a part of the article being held is viewable to enable optical measurements.

40. The measurement station according to Claim 2, wherein said holding unit comprises an assembly movable along an axis perpendicular to the article’

s surface, thereby enabling said holding of the article in the measuring position.

41. The measurement station according to Claim 2, having a footprint in at least one dimension of about a size of the article’

s diameter.

42. The measurement station according to Claim 2, wherein said processing machine is a polisher.

43. The measurement station according to Claim 2, configured for receiving the processed article from the processing machine via said article transfer assembly of the exit station.

44. The measurement station according to Claim 2, wherein said optical system includes a focusing optics for focusing the illuminated light onto the article and collecting the light from the illuminated article.

45. The measurement station according to Claim 35, wherein the support assembly is configured to receive the article from the article transfer assembly of the exit station and to enable the article transfer into the measuring position.

46. The measurement station according to Claim 35, wherein the support assembly includes two support elements displaceable with respect to each other.

47. The measurement station according to Claim 35, wherein the support assembly is configured for supporting the article at its periphery region.

48. The measurement station according to Claim 2, wherein the imaging system is operable to perform pattern recognition.

49. The measurement station according to Claim 44, wherein the optical system comprises a fiber optics for directing light from a light source towards the focusing optics.

50. The measurement station according to Claim 44, wherein the focusing optics comprises an objective lens arrangement.

51. The measurement station according to Claim 2, wherein the imaging system includes a lens arrangement accommodated between an imaging detector and the beam splitting assembly.

52. The measurement station according to Claim 2, wherein the optical system comprises a lens arrangement accommodated between the beam splitting assembly and the spectrophotometer.

53. The measurement station according to Claim 2, wherein the optical system is configured for providing substantially normal incidence of the illuminating light.

54. The measurement station according to Claim 31, wherein the pin hole mirror is accommodated so as to be an aperture stop in an optical path of the collected light, the pin hole mirror thereby appearing as a dark area in an image of a measurement spot on the article and allowing for locating the measurement spot.

55. The measurement station according to Claim 2, wherein the holding unit comprises a vacuum assembly for holding the article by vacuum.

56. The measurement station according to Claim 35, wherein the support assembly includes two support elements displaceable with respect to each other.

57. The measurement station according to Claim 2, configured to be installable within the exit station of the processing machine.

58. The measurement station according to Claim 2, wherein said optical system is configured and operable for measuring in the patterned article.

59. The measurement station according to Claim 5, comprising a support assembly for supporting the article.

60. The measurement station according to Claim 59, wherein said support assembly is configured for supporting the article that is to be received from the holding unit.

61. The measurement station according to Claim 59, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

62. The measurement station according to Claim 60, wherein said support assembly is configured for supporting the article that is to be received by the holding unit.

63. The measurement station according to Claim 5, wherein the optical system and the holding unit are separated by a window through which at least a part of the article being held is viewable to enable optical measurements.

64. The measurement station according to Claim 5, wherein said holding unit comprises an assembly movable along an axis perpendicular to the article’

s surface, thereby enabling said holding of the article in the measuring position.

65. The measurement station according to Claim 5, having a footprint in at least one dimension of about a size of the article’

s diameter.

66. The measurement station according to Claim 5, wherein said processing station is a polisher.

67. The measurement station according to Claim 5, configured for receiving the processed article from the processing machine via said article transfer assembly of the exit station.

68. The measurement station according to Claim 5, wherein said optical system includes a focusing optics for focusing the illuminated light onto the article and collecting the light from the illuminated article.

69. The measurement station according to Claim 59, wherein the support assembly is configured to receive the article from the article transfer assembly of the exit station and to enable the article transfer into the measuring position.

70. The measurement station according to Claim 59, wherein the support assembly includes two support elements displaceable with respect to each other.

71. The measurement station according to Claim 59, wherein the support assembly is configured for supporting the article at its periphery region.

72. The measurement station according to Claim 5, wherein the imaging system is operable to perform pattern recognition.

73. The measurement station according to Claim 68, wherein the optical system comprises a fiber optics for directing light from a light source towards the focusing optics.

74. The measurement station according to Claim 68, wherein the focusing optics comprises an objective lens arrangement.

75. The measurement station according to Claim 5, wherein the imaging system includes a lens arrangement accommodated between an imaging detector and the beam splitting assembly.

76. The measurement station according to Claim 5, wherein the optical system comprises a lens arrangement accommodated between the beam splitting assembly and the spectrophotometer.

77. The measurement station according to Claim 5, wherein the optical system is configured for providing substantially normal incidence of the illuminating light.

78. The measurement station according to Claim 5, wherein the beam splitting means comprises a pin hole mirror that is accommodated so as to be an aperture stop in an optical path of the collected light, the pin hole mirror thereby appearing as a dark area in an image of a measurement spot on the article and allowing for locating the measurement spot.

79. The measurement station according to Claim 5, wherein the holding unit comprises a vacuum assembly for holding the article by vacuum.

80. The measurement station according to Claim 59, wherein the support assembly includes two support elements displaceable with respect to each other.

81. The measurement station according to Claim 5, configured to be installable within the exit station of the processing machine.

82. The measurement station according to Claim 5, wherein said optical system is configured and operable for measuring in the patterned article.

83. The measurement station according to Claim 7, wherein the optical system and the holding unit are separated by a window through which at least a part of the article being held is viewable to enable optical measurements.

84. The measurement station according to Claim 7, wherein said holding unit comprises an assembly movable along an axis perpendicular to the article’

s surface, thereby enabling said holding of the article in the measuring position.

85. The measurement station according to Claim 7, having a footprint in at least one dimension of about a size of the article’

s diameter.

86. The measurement station according to Claim 7, wherein said processing station is a polisher.

87. The measurement station according to Claim 7, configured for receiving the processed article from the processing machine via said article transfer assembly of the exit station.

88. The measurement station according to Claim 7, wherein said optical system includes a focusing optics for focusing the illuminated light onto the article and collecting the light from the illuminated article.

89. The measurement station according to Claim 7, wherein the imaging system is operable to perform pattern recognition.

90. The measurement station according to Claim 88, wherein the optical system comprises a fiber optics for directing light from a light source towards the focusing optics.

91. The measurement station according to Claim 88, wherein the focusing optics comprises an objective lens arrangement.

92. The measurement station according to Claim 7, wherein the imaging system includes a lens arrangement accommodated between an imaging detector and the beam splitting assembly.

93. The measurement station according to Claim 7, wherein the optical system comprises a lens arrangement accommodated between the beam splitting assembly and the spectrophotometer.

94. The measurement station according to Claim 7, wherein the optical system is configured for providing substantially normal incidence of the illuminating light.

95. The measurement station according to Claim 7, wherein the beam splitting means comprises a pin hole mirror that is accommodated so as to be an aperture stop in an optical path of the collected light, the pin hole mirror thereby appearing as a dark area in an image of a measurement spot on the article and allowing for locating the measurement spot.

96. The measurement station according to Claim 7, wherein the holding unit comprises a vacuum assembly for holding the article by vacuum.

97. The measurement station according to Claim 7, configured to be installable within the exit station of the processing machine.

98. The measurement station according to Claim 7, wherein said optical system is configured and operable to measure in the patterned article.

99. The measurement station according to Claim 13, wherein said processing station is a polisher.

100. The measurement station according to Claim 13, configured for receiving the processed article from the processing machine via said article transfer assembly of the exit station.

101. The measurement station according to Claim 13, wherein said optical system includes a focusing optics for focusing the illuminated light onto the article and collecting the light from the illuminated article.

102. The measurement station according to Claim 13, wherein the imaging system is operable to perform pattern recognition.

103. The measurement station according to Claim 101, wherein the optical system comprises a fiber optics for directing light from a light source towards the focusing optics.

104. The measurement station according to Claim 101, wherein the focusing optics comprises an objective lens arrangement.

105. The measurement station according to Claim 13, wherein the imaging system includes a lens arrangement accommodated between an imaging detector and the beam splitting assembly.

106. The measurement station according to Claim 13, wherein the optical system comprises a lens arrangement accommodated between the beam splitting assembly and the spectrophotometer.

107. The measurement station according to claim 13, wherein the optical system is configured for providing substantially normal incidence of the illuminating light.

108. The measurement station according to Claim 13, wherein the beam splitting means comprises a pin hole mirror that is accommodated so as to be an aperture stop in an optical path of the collected light, the pin hole mirror thereby appearing as a dark area in an image of a measurement spot on the article and allowing for locating the measurement spot.

109. The measurement station according to Claim 13, wherein the holding unit comprises a vacuum assembly for holding the article by vacuum.

110. The measurement station according to Claim 13, configured to be installable within the exit station of the processing machine.

111. The measurement station according to Claim 13, wherein said optical system is configured and operable to measure in the patterned article.

112. A measurement station for use with a processing machine, which includes a polisher for polishing an article and an exit station including an article transfer assembly and at least one articles’

cassette, the measurement station being so dimensioned as to be installable in association with the exit station of the processing machine and comprising an optical system and a holding unit for receiving and holding the article in a measuring position during measurements, said optical system comprising a spectrophotometer;

an imaging system operable to locate measurements;

a beam directing assembly for directing illuminating light towards the article and directing collected light from the article towards a beam splitting assembly including a pin hole mirror for separating a first portion of the collected light to propagate towards the spectrophotometer and a second portion to propagate to said imaging system.

113. A measurement station for use with a processing machine, which includes a processing station for processing an article and an exit station including an article transfer assembly and at least one articles’

cassette, the measurement station being so dimensioned as to be installable in association with the exit station of the processing machine and comprising an optical system, a holding unit for receiving and holding the article in a measuring position during measurements, and a support assembly for supporting the article while transporting it in between said transfer assembly of the exit station and said holding unit, said optical system being configured and operable to enable measurement of a thickness of at least a top layer of the article, said optical system including a spectrophotometer;

an imaging system operable to locate measurements;

a beam directing assembly for directing illuminating light towards the article and directing collected light from the article towards a beam splitting assembly for separating a first portion of the collected light to propagate towards the spectrophotometer and a second portion to propagate to said imaging system.

114. A measurement station for use with a processing machine, which includes a processing station for processing an article and an exit station including an article transfer assembly and at least one articles’

cassette, the measurement station being so dimensioned as to be installable in association with the exit station of the processing machine and comprising an optical system, and a holding unit for receiving and holding the article in a measuring position during measurements, said optical system being configured and operable to enable measurement of a thickness of at least a top layer of the article, said optical system including a spectrophotometer;

an imaging system operable to locate measurements;

a beam directing assembly for directing illuminating light towards the article and directing collected light from the article towards a beam splitting assembly including a pin hole mirror for separating a first portion of the collected light to propagate towards the spectrophotometer and a second portion to propagate to said imaging system.