Method and apparatus for three dimensional inspection of electronic components

• US 6,915,007 B2
• Filed: 04/27/2001
• Issued: 07/05/2005
• Est. Priority Date: 01/16/1998
• Status: Expired due to Fees

• Current Assignee: Scanner Technologies Corporation
• Original Assignee: Elaine Beaty, Elwin M. Beaty
• Inventors: Mork, David P., Beaty, Elwin M.
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US09/844,626
• Publication Number:
  US 20020034324A1
• Time in Patent Office: 1,530 Days
• Field of Search: 382145-151, 382/154, 382/199, 348/87, 348/94, 348/95, 348/126, 348/131, 356/237.1, 356/360, 356/326, 356/377, 250/559.23, 250/559.31, 250/559.34, 250/559.4, 702/150, 702/152, 702/153
• US Class Current: 382/145
• CPC Class Codes: G06T 2207/30152 Solder
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: H05K 13/0818 Setup of monitoring devices prior to starting mounting operations; Teaching of monitoring devices for specific products; Compensation of drifts during operation, e.g. due to temperature shifts

Abstract

A three dimensional inspection method for inspecting ball array devices having a plurality of balls, where the ball array device is positioned in an optical system. The inspection method includes the steps of illuminating at least one ball on the ball array device, and disposing a sensor, a first optical element and a second optical element in relation to the ball array device so that the sensor obtains at least two differing views of the at least one ball, the sensor providing an output representing the at least two differing views. The output is processed using a triangulation method to calculate a three dimensional position of the at least one ball with reference to a pre-calculated calibration plane.

Claims

1. A three dimensional inspection method for inspecting ball grid array devices having a plurality of balls, wherein the ball grid array device is positioned in an optical system, the inspection method comprising:

illuminating at least one ball on the ball array device using a fixed illumination system;

disposing a single sensor, a first optical element and a second optical element in relation to the ball grid array device so that the sensor obtains at least two differing views of the at least one ball, the sensor providing output representing the at least two differing views; and

processing the output using a triangulation method to calculate a three dimensional position of the at least one ball with reference to a pre-calculated calibration plane.

2. The three dimensional inspection method of claim 1 wherein the pre-calculated calibration plane comprises a coordinate system having X, Y and Z axes and wherein an X measurement value is proportional to a Z measurement value.

3. The three dimensional inspection method of claim 1 wherein the pre-calculated calibration plane comprises a coordinate system having X, Y and Z axes and wherein an XY measurement value is proportional to a Z measurement value.

4. The three dimensional inspection method of claim 1 wherein the pre-calculated calibration plane comprises a coordinate system having X, Y and Z axes and wherein a Y measurement value is proportional to a Z measurement value.

5. The three dimensional inspection method of claim 1 wherein the triangulation method is based on determining a center of the ball in a first view and determining a ball top location in a second view.

6. The three dimensional inspection method of claim 1 wherein the pre-calculated calibration plane is defined by measuring a calibration pattern.

7. The three dimensional inspection method of claim 1 wherein the second optical element comprises a mirror.

8. The three dimensional inspection method of claim 1 wherein the second optical element comprises a prism.

9. The three dimensional inspection method of claim 1 wherein one of the at least two differing views is obtained at a low angle of view.

10. The three dimensional inspection method of claim 1 wherein the sensor and the second optical element are positioned to receive light from different angles relative to the calibration plane.

11. The three dimensional inspection method of claim 1 wherein the sensor comprises a charged coupled device array.

12. The three dimensional inspection method of claim 1 wherein the sensor comprises a complementary metal oxide semiconductor device array.

13. The three dimensional inspection method of claim 1 wherein the processing includes applying grayscale edge detection to locate ball positions.

14. The three dimensional inspection method of claim 1 wherein the processing includes applying threshold analysis.

15. The three dimensional inspection method of claim 1 wherein the first optical element comprises a lens.

16. The three dimensional inspection method of claim 1 wherein the first optical element comprises a pin-hole lens.

17. The three dimensional inspection method of claim 1 wherein the first optical element comprises a plurality of lens elements.

18. The three dimensional inspection method of claim 1 wherein the first optical element comprises a telecentric lens.

19. The three dimensional inspection method of claim 1 wherein the ball grid array devices comprise bump on wafer devices.

20. The three dimensional inspection method of claim 1 wherein processing the output is carried out on a personal computer.

21. The three dimensional inspection method of claim 1 wherein the sensor includes a solid state sensor array.

22. The three dimensional inspection method of claim 1 wherein one of the views comprises a segment having a crescent shape.

23. The three dimensional inspection method of claim 1 wherein the triangulation method uses state values derived from the ball grid array device.

24. The three dimensional inspection method of claim 1, wherein the at least one ball on the ball grid array device being inspected comprises a contact.

25. The three dimensional inspection method of claim 1, wherein the at least one ball on the ball grid array device being inspected comprises a pin.

26. The three dimensional inspection method of claim 1, wherein the at least one ball on the ball grid array device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

27. The three dimensional inspection method of claim 1, wherein the two different views of the at least one ball are obtained in a single image.

28. The three dimensional inspection method of claim 1, wherein the two different views of the at least one ball are each obtained in a separate image.

29. A three dimensional inspection method for ball grid array devices having plurality of balls, the method comprising:

illuminating the ball array device using a fixed illumination system;

disposing a single sensor to receive light at a first angle relative to the ball grid array device;

positioning a first optical element to transmit light to the sensor, where the sensor obtains a first view of the ball grid array device;

disposing a second optical element to receive light at a second angle different from the first angle and to transmit a second view of the ball grid array device to the sensor;

transmitting image information from the sensor; and

processing the image information by applying triangulation calculations to measurements of the image information so as to calculate a three dimensional position of at least one ball with reference to a pre-calulated calibration plane.

30. The three dimensional inspection method of claim 29 wherein the calibration plane comprises a coordinate system having X, Y and Z axes and wherein an X measurement value is proportional to a Z measurement value.

31. The three dimensional inspection method of claim 29 wherein the calibration plane comprises a coordinate system having X, Y and Z axes and wherein an XY measurement value is proportional to a Z measurement value.

32. The three dimensional inspection method of claim 29 wherein the calibration plane comprises a coordinate system having X, Y and Z axes and wherein a Y measurement value is proportional to a Z measurement value.

33. The three dimensional inspection method of claim 29 wherein the pre-calculated calibration plane is defined by measuring a calibration pattern.

34. The three dimensional inspection method of claim 29 wherein the second optical element comprises a mirror.

35. The three dimensional inspection method of claim 29 wherein the second optical element comprises a prism.

36. The three dimensional inspection method of claim 29 wherein the illuminating comprises illuminating with a ring light.

37. The three dimensional inspection method of claim 29 wherein the illuminating comprises illuminating with a plurality of light emitting diodes.

38. The three dimensional inspection method of claim 37, wherein at least two of the plurality of light emitting diodes are spectrally diverse from one another.

39. The three dimensional inspection method of claim 29 wherein the illuminating comprises illuminating with reflected light.

40. The three dimensional inspection method of claim 29 wherein the sensor comprises a charged coupled device array.

41. The three dimensional inspection method of claim 29 wherein the sensor comprises a complementary metal oxide semiconductor device array.

42. The three dimensional inspection method of claim 29 wherein the ball grid array devices comprise bump on wafer devices.

43. The three dimensional inspection method of claim 29 wherein the processing includes applying grayscale edge detection to locate ball positions.

44. The three dimensional inspection method of claim 29 wherein the processing includes applying threshold analysis.

45. The three dimensional inspection method of claim 29 wherein the first optical element comprises a lens.

46. The three dimensional inspection method of claim 29 wherein the first optical element comprises a pin-hole lens.

47. The three dimensional inspection method of claim 29 wherein the first optical element comprises a plurality of lens elements.

48. The three dimensional inspection method of claim 29 wherein the first optical element comprises a telecentric lens.

49. The three dimensional inspection method of claim 29 wherein the sensor includes a solid state sensor array.

50. The three dimensional inspection method of claim 29 wherein the processing is carried out on a personal computer.

51. The three dimensional inspection method of claim 29 wherein the second optical element reflects a view to the sensor where at least one ball of the array device exhibits a crescent shape.

52. The three dimensional inspection method of claim 29 wherein the triangulation calculations use state values derived from the ball grid array device.

53. The three dimensional inspection method of claim 29, wherein the at least one ball on the ball grid array device being inspected comprises a contact.

54. The three dimensional inspection method of claim 29, wherein the at least one ball on the ball grid array device being inspected comprises a pin.

55. The three dimensional inspection method of claim 29, wherein the at least one ball on the ball grid array device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

56. The three dimensional inspection method of claim 29, wherein the first and second views of the at least one ball are obtained in a single image.

57. The three dimensional inspection method of claim 29, wherein the first and second views of the at least one ball are each obtained in a separate image.

58. A three dimensional inspection method for ball grid array devices having plurality of balls, the method comprising:

illuminating a ball grid array device using a fixed illumination system;

disposing a single sensor to receive light at a first angle relative to the ball grid array device, wherein the sensor includes a solid state sensor array;

disposing a first optical element to transmit light to the sensor, where the sensor obtains a first view of the ball grid array device;

disposing a second optical element to receive light at a second angle different from the first angle, and to transfer a second view of the ball grid array device to the sensor;

transmitting image information representing the first view and the second view; and

processing the image information by applying triangulation calculations to measurements of the image information so as to calculate a three dimensional position of at least one ball with reference to a precalculated calibration plane, wherein the calibration plane comprises a coordinate system having X, Y and Z axes, and wherein an X measurement value is proportional to a Z measurement value.

59. The three dimensional inspection method of claim 58 wherein an XY measurement value is proportional to a Z measurement value.

60. The three dimensional inspection method of claim 58 wherein a Y measurement value is proportional to a Z measurement value.

61. The three dimensional inspection method of claim 58 wherein the pre-calculated calibration plane is defined by measuring a calibration pattern.

62. The three dimensional inspection method of claim 58 wherein the processing comprises applying grayscale edge detection to locate ball positions.

63. The three dimensional inspection method of claim 58 wherein the processing includes applying threshold analysis.

64. The three dimensional inspection method of claim 58 wherein the illuminating comprises illuminating with a plurality of light emitting diodes.

65. The three dimensional inspection method of claim 64, wherein at least two of the plurality of light emitting diodes are spectrally diverse from one another.

66. The three dimensional inspection method of claim 58 wherein illuminating comprises illuminating with reflected light.

67. The three dimensional inspection method of claim 58 wherein the ball grid array devices comprise bump on wafer devices.

68. The three dimensional inspection method of claim 58 wherein the solid state sensor array includes a charged coupled device array.

69. The three dimensional inspection method of claim 58 wherein the solid state sensor array includes a complementary metal oxide semiconductor array.

70. The three dimensional inspection method of claim 58 wherein the second optical element comprises a mirror.

71. The three dimensional inspection method of claim 58 wherein the second optical element comprises a prism.

72. The three dimensional inspection method of claim 58 wherein the second view comprises a segment having a crescent shape.

73. The three dimensional inspection method of claim 58 wherein the image information representing the first view and the second view is acquired using a frame grabber.

74. The three dimensional inspection method of claim 58 wherein processing the image information is carried out on a personal computer.

75. The three dimensional inspection method of claim 58 wherein the first optical element comprises a lens.

76. The three dimensional inspection method of claim 58 wherein the first optical element comprises a pin-hole lens.

77. The three dimensional inspection method of claim 58 wherein the first optical element comprises a plurality of lens elements.

78. The three dimensional inspection method of claim 58 wherein the first optical element comprises a telecentric lens.

79. The three dimensional inspection method of claim 58 wherein the triangulation calculations use state values derived from the ball grid array device.

80. The three dimensional inspection method of claim 58, wherein the at least one ball on the ball grid array device being inspected comprises a contact.

81. The three dimensional inspection method of claim 58, wherein the at least one ball on the ball grid array device being inspected comprises a pin.

82. The three dimensional inspection method of claim 58, wherein the at least one ball on the ball grid array device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

83. The three dimensional inspection method of claim 58, wherein the image information representing the first view and the second view comprise a single image.

84. The three dimensional inspection method of claim 58, wherein the image information representing the first view and the second view each comprise a separate image.

85. A three dimensional inspection method for ball grid array devices having a plurality of balls, the method comprising:

measuring a calibration plate to determine a calibration plane;

illuminating a ball grid array device using a fixed illumination system;

disposing a single sensor to receive light at a first angle relative to the ball grid array device, wherein the sensor includes a solid state sensor array;

disposing a first optical element to transmit light to the sensor, where the sensor obtains a first view of the ball grid array device;

disposing a second optical element to receive light at a second angle different from the first angle, and to transfer a second view of the ball grid array device to the sensor;

transmitting image information representing the first view and the second view; and

processing the image information by applying triangulation calculations to measurements of the image information so as to calculate a three dimensional position of at least one ball with reference to the calibration plane, wherein the calibration plane comprises a coordinate system having X, Y and Z axes, and wherein an X measurement value is proportional to a Z measurement value.

86. A three dimensional inspection process for ball grid array devices having a plurality of balls, wherein the ball grid array device is positioned in a fixed optical system, the process comprising:

illuminating the ball grid array device using a fixed illumination system;

taking a first image of the ball grid array device with a single camera disposed in a fixed focus position relative to the ball grid array device to obtain a circular doughnut shape image from at least one ball;

taking a second image of the ball grid array device with an optical element disposed in a fixed focus position relative to the ball grid array device to transmit a side view image of the at least one ball to the camera; and

processing the first image and the second image using a triangulation method to calculate a three dimensional position of the at least one ball with reference to a pre-calculated calibration plane.

87. The three dimensional inspection process of claim 86 wherein the second image comprises a segment having a crescent shape.

88. The three dimensional inspection process of claim 86 wherein the calibration plane comprises a coordinate system having X, Y and Z axes and wherein an X measurement value is proportional to a Z measurement value.

89. The three dimensional inspection process of claim 86 wherein the triangulation method to calculate a three dimensional position of the at least one ball is based on determining a center of the ball in the first image and determining a ball top location in the second image.

90. The three dimensional inspection process of claim 86 wherein the pre-calculated calibration plane is defined through measuring a calibration pattern.

91. The three dimensional inspection process of claim 86 wherein the optical element comprises a mirror.

92. The three dimensional inspection process of claim 86 wherein the second image is obtained at a low angle of view.

93. The three dimensional inspection process of claim 86 wherein the camera and the optical element are fixed at different angles relative to the calibration plane.

94. The three dimensional inspection process of claim 86 wherein the camera comprises a charged coupled device array.

95. The three dimensional inspection process of claim 86 wherein processing the first image and the second image comprises employing grayscale edge detection to locate ball positions.

96. The three dimensional inspection process of claim 86 wherein illuminating the ball grid array device employs diffuse illumination.

97. The three dimensional inspection process of claim 86 wherein the ball grid array devices comprise bump on wafer devices.

98. The three dimensional inspection process of claim 86 wherein the triangulation method uses state values derived from the ball grid array device.

99. The three dimensional inspection process of claim 86 wherein the processing includes applying threshold analysis.

100. The three dimensional inspection process of claim 86 wherein the sensor comprises a charged coupled device array.

101. The three dimensional inspection process of claim 86, wherein the at least one ball on the ball grid array device being inspected comprises a contact.

102. The three dimensional inspection process of claim 86, wherein the at least one ball on the ball grid array device being inspected comprises a pin.

103. The three dimensional inspection process of claim 86, wherein the at least one ball on the ball grid array device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

104. The three dimensional inspection process of claim 86, wherein the circular doughnut shape image and the side view image comprise a single image.

105. The three dimensional inspection process of claim 86, wherein the circular doughnut shape image and the side view image each comprise a separate image.