Method of manufacturing electronic components including a method for three dimensional inspection

• US 20050190961A1
• Filed: 02/28/2005
• Published: 09/01/2005
• Est. Priority Date: 01/16/1998
• Status: Active Grant

• Current Assignee: Scanner Technologies Corporation
• Original Assignee: Scanner Technologies Corporation
• Inventors: Mork, David P., Beaty, Elwin M.
• Granted Patent: US 7,085,411 B2
• Time in Patent Office: Days
• US Class Current: 382/150
• CPC Class Codes: G06T 2200/04 involving 3D image data
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• 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 calibration and part inspection method for the inspection of ball grid array, BGA, devices. One or more cameras image a precision pattern mask with dot patterns deposited on a transparent reticle. The precision pattern mask is used for calibration of the system. A light source and overhead light reflective diffuser provide illumination. A camera images the reticle precision pattern mask from directly below. An additional mirror or prism located below the bottom plane of the reticle reflects the reticle pattern mask from a side view, through prisms or reflective surfaces, into the camera. By imaging more than one dot pattern the missing state values of the system can be resolved using a trigonometric solution. The reticle with the pattern mask is removed after calibration and the BGA to be inspected is placed with the balls facing downward, in such a manner as to be imaged by a single camera, or optionally, via additional cameras. The scene of the part can thus be triangulated and the dimensions of the BGA are determined.

Claims

1. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain both a bottom view of the lead and a side perspective view of the lead;

receiving at least the bottom view and the side perspective view of the lead using a single camera;

transmitting the bottom view and the side perspective view of the lead to memory as pixel values;

determining a first lead reference pixel position in the bottom view;

determining a second lead reference pixel position in the side view; and

converting the first and second lead reference pixel positions into a world value by using pixel values and parameters determined during a calibration.

2. The method of manufacturing of claim 1, wherein illuminating the lead is achieved using a single light source.

3. The method of manufacturing of claim 1, wherein illuminating the lead is achieved using more than one light source.

4. The method of manufacturing of claim 3, wherein the more than one light sources used are spectrally diverse from one another.

5. The method of manufacturing of claim 1, wherein the lead on the BGA device being inspected comprises a contact.

6. The method of manufacturing of claim 1, wherein the lead on the BGA device being inspected comprises a pin.

7. The method of manufacturing of claim 1, wherein the lead on the BGA device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

8. The method of manufacturing of claim 1, wherein the bottom view of the lead and a side perspective view of the lead are obtained in a single image.

9. The method of manufacturing of claim 1, wherein the bottom view of the lead and a side perspective view of the lead are obtained in more than one image.

10. The method of manufacturing of claim 1, wherein the illuminating is with a diffuse light.

11. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain both a bottom view of the lead and a side perspective view of the lead;

receiving at least the bottom view and the side perspective view of the lead using a single camera;

transmitting the bottom view and the side perspective view of the lead to memory as pixel values;

determining a first lead reference pixel position in the bottom view;

determining a second lead reference pixel position in the side view; and

converting the first lead reference pixel position into a first world value and the second lead reference pixel position into a second world value by using pixel values and parameters determined during a calibration.

12. The method of manufacturing of claim 11, wherein illuminating the lead is achieved using a single light source.

13. The method of manufacturing of claim 11, wherein illuminating the lead is achieved using more than one light source.

14. The method of manufacturing of claim 13, wherein the more than one light sources used are spectrally diverse from one another.

15. The method of manufacturing of claim 11, wherein the lead on the BGA device being inspected comprises a contact.

16. The method of manufacturing of claim 11, wherein the lead on the BGA device being inspected comprises a pin.

17. The method of manufacturing of claim 11, wherein the lead on the BGA device being inspected is selected from the group consisting of:

bump contact, ball contact, pad, and pedestal.

18. The method of manufacturing of claim 11, wherein the bottom view of the lead and a side perspective view of the lead are obtained in a single image.

19. The method of manufacturing of claim 11, wherein the bottom view of the lead and a side perspective view of the lead are obtained in more than one image.

20. The method of manufacturing of claim 11, wherein the illuminating is with a diffuse light.

21. A method of manufacturing a ball grid array (BGA) device, the method comprising:

combining an electronic circuit with a BGA package having a plurality of balls;

making a three dimensional inspection of a lead on the BGA package with the ball grid array device being positioned in an optical system; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating at least one ball on the BGA package using a fixed illumination system;

disposing a single sensor, a first optical element and a second optical element in relation to the BGA package 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.

22. The method of manufacturing of claim 21, 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.

23. The method of manufacturing of claim 21, 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.

24. The method of manufacturing of claim 21, 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.

25. The method of manufacturing of claim 21, 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.

26. The method of manufacturing of claim 21, wherein the pre-calculated calibration plane is defined by measuring a calibration pattern.

27. The method of manufacturing of claim 21, wherein one of the at least two differing views is obtained at a low angle of view.

28. The method of manufacturing of claim 21, wherein the sensor and the second optical element are positioned to receive light from different angles relative to the calibration plane.

29. The method of manufacturing of claim 21, wherein the processing includes applying grayscale edge detection to locate ball positions.

30. The method of manufacturing of claim 21, wherein the processing includes applying threshold analysis.

31. The method of manufacturing of claim 21, wherein the BGA device comprises a bump on wafer device.

32. The method of manufacturing of claim 21, wherein processing the output is carried out using a general purpose computer.

33. The method of manufacturing of claim 21, wherein one of the views comprises a segment having a crescent shape.

34. The method of manufacturing of claim 21, wherein the two different views of the at least one ball are obtained in a single image.

35. The method of manufacturing of claim 21, wherein the two different views of the at least one ball are each obtained in a separate image.

36. A method of manufacturing a ball grid array (BGA) device, the method comprising:

combining an electronic circuit with a BGA package having a plurality of balls;

making a three dimensional inspection of a lead on the BGA package with the ball grid array device being positioned in an optical system; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the BGA package using a fixed illumination system;

disposing a single sensor to receive light at a first angle relative to the BGA package;

positioning a first optical element to transmit light to the sensor, where the sensor obtains a first view of the BGA package;

disposing a second optical element to receive light at a second angle different from the first angle and to provide a second view of the BGA package 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-calculated calibration plane.

37. The method of manufacturing of claim 36, wherein the illuminating comprises illuminating with a ring light.

38. The method of manufacturing of claim 36, wherein the illuminating comprises illuminating with a plurality of light emitting diodes.

39. The method of manufacturing of claim 38, wherein at least two of the plurality of light emitting diodes are spectrally diverse from one another.

40. The method of manufacturing of claim 36, wherein the illuminating comprises illuminating with reflected light.

41. The method of manufacturing of claim 36, 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.

42. The method of manufacturing of claim 36, 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.

43. The method of manufacturing of claim 36, 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.

44. The method of manufacturing of claim 36, wherein the pre-calculated calibration plane is defined by measuring a calibration pattern.

45. The method of manufacturing of claim 36, wherein the processing includes applying grayscale edge detection to locate ball positions.

46. The method of manufacturing of claim 36, wherein the processing includes applying threshold analysis.

47. The method of manufacturing of claim 36, wherein one of the views comprises a segment having a crescent shape.

48. The method of manufacturing of claim 36, wherein the first and second views of the at least one ball are obtained in a single image.

49. The method of manufacturing of claim 36, wherein the first and second views of the at least one ball are each obtained in a separate image.

50. A method of manufacturing a ball grid array (BGA) device, the method comprising:

combining an electronic circuit with a BGA package having a plurality of balls;

making a three dimensional inspection of a lead on the BGA package with the ball grid array device being positioned in an optical system; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the BGA package using a fixed illumination system;

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

taking a second image of the BGA package with an optical element disposed in a fixed focus position relative to the BGA package 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.

51. The method of manufacturing of claim 50, wherein the second image comprises a segment having a crescent shape.

52. The method of manufacturing of claim 50, 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.

53. The method of manufacturing of claim 50, 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.

54. The method of manufacturing of claim 50, wherein the pre-calculated calibration plane is defined through measuring a calibration pattern.

55. The method of manufacturing of claim 50, wherein the second image is obtained at a low angle of view.

56. The method of manufacturing of claim 50, wherein the camera and the optical element are fixed at different angles relative to the calibration plane.

57. The method of manufacturing of claim 50, wherein processing the first image and the second image comprises employing grayscale edge detection to locate ball positions.

58. The method of manufacturing of claim 50, wherein illuminating the ball grid array device employs diffuse illumination.

59. The method of manufacturing of claim 50, wherein the triangulation method uses state values derived from the ball grid array device.

60. The method of manufacturing of claim 50, wherein the processing includes applying threshold analysis.

61. The method of manufacturing of claim 50, wherein the at least one ball on the ball grid array device being inspected comprises a contact.

62. The method of manufacturing of claim 50, wherein the at least one ball on the ball grid array device being inspected comprises a pin.

63. The method of manufacturing of claim 50, 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.

64. The method of manufacturing of claim 50, wherein the circular doughnut shape image and the side view image comprise a single image.

65. The method of manufacturing of claim 50, wherein the circular doughnut shape image and the side view image each comprise a separate image.

66. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain two differing views of the lead;

disposing at least one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using parameters determined during a calibration.

67. The method of manufacturing of claim 66, wherein the lead on the BGA device being inspected comprises a contact.

68. The method of manufacturing of claim 66, wherein the lead on the BGA device being inspected is selected from the group consisting of:

bump contact, ball contact, pin contact, pad, and pedestal.

69. The method of manufacturing of claim 66, wherein illuminating the lead is achieved using a single light source.

70. The method of manufacturing of claim 66, wherein illuminating the lead is achieved using more than one light source.

71. The method of manufacturing of claim 70, wherein the more than one light sources used are spectrally diverse from one another.

72. The method of manufacturing of claim 66, wherein the illuminating is with a diffuse light.

73. The method of manufacturing of claim 66, wherein the illuminating is with a ring light.

74. The method of manufacturing of claim 66, wherein the illuminating comprises illuminating with a plurality of light emitting diodes.

75. The method of manufacturing of claim 66, wherein a first view of the lead and a second view of the lead are obtained in a single image.

76. The method of manufacturing of claim 66, wherein a first view of the lead and a second view of the lead are obtained in two images.

77. The method of manufacturing of claim 66, wherein a first view of the lead and a second view of the lead are obtained in more than two images.

78. The method of manufacturing of claim 66, wherein the at least two differing views of the lead are obtained using a single sensor.

79. The method of manufacturing of claim 66, wherein the at least two differing views of the lead are obtained using two sensors.

80. The method of manufacturing of claim 66, wherein the at least two differing views of the lead are obtained using more than two sensors.

81. The method of manufacturing of claim 66, wherein the at least one sensor is selected from the group consisting of:

digital camera, image sensor, charged coupled device array, and complementary metal-oxide semiconductor.

82. The method of manufacturing of claim 66, wherein one of the views comprises a segment having a donut shape.

83. The method of manufacturing of claim 66, wherein one of the views comprises a segment having a crescent shape.

84. The method of manufacturing of claim 66, wherein one of the views is obtained at a low angle of view.

85. The method of manufacturing of claim 66, wherein one of the views is obtained at a 0 degree angle of view.

86. The method of manufacturing of claim 66, wherein one of the views is obtained at a 90 degree angle of view.

87. The method of manufacturing of claim 66, wherein a displacement in a first view is proportional to a displacement in a second view.

88. The method of manufacturing of claim 66, wherein the first lead reference position determined from a center of the lead in a first view.

89. The method of manufacturing of claim 66, wherein the second lead reference position is determined from a top location of the lead in a second view.

90. The method of manufacturing of claim 66, wherein the first lead reference position is determined from a pixel position.

91. The method of manufacturing of claim 66, wherein the first lead reference position is determined from a world position.

92. The method of manufacturing of claim 66, wherein the second lead reference position is determined from a pixel position.

93. The method of manufacturing of claim 66, wherein the second lead reference position is determined from a world position.

94. The method of manufacturing of claim 66, wherein the first lead reference position is determined from grayscale edge detection.

95. The method of manufacturing of claim 66, wherein the first lead reference position is determined from threshold analysis.

96. The method of manufacturing of claim 66, wherein the first lead reference position is determined from convolution.

97. The method of manufacturing of claim 66, wherein the second lead reference position is determined from grayscale edge detection.

98. The method of manufacturing of claim 66, wherein the second lead reference position is determined from threshold analysis.

99. The method of manufacturing of claim 66, wherein the first second reference position is determined from convolution.

100. The method of manufacturing of claim 66, wherein converting the first and second lead reference positions into a world value is carried out using a triangulation calculation.

101. The method of manufacturing of claim 66, wherein converting the first and second lead reference positions into a world value is carried out using an interpolation calculation.

102. The method of manufacturing of claim 66, wherein converting the first and second lead reference positions into a world value is carried out using a general purpose computer.

103. The method of manufacturing of claim 66, wherein the world value comprises an X, Y, and Z position.

104. The method of manufacturing of claim 66, wherein the world value comprises a Z distance from a calibration plane.

105. The method of manufacturing of claim 66, wherein the world value comprises a Z distance from a regression plane.

106. The method of manufacturing of claim 66, wherein the world value comprises a Z distance from a seating plane.

107. The method of manufacturing of claim 66, wherein the parameters are determined by measuring a calibration pattern of known dimension and spacing.

108. The method of manufacturing of claim 66, wherein the parameters are determined by measuring a leads on a ball array device.

109. The method of manufacturing of claim 66, wherein the parameters define a calibration plane.

110. The method of manufacturing of claim 109, wherein the calibration plane comprises a coordinate system having X, Y and Z axes.

111. The method of manufacturing of claim 109, wherein the calibration plane is determined by measuring a calibration pattern.

112. The method of manufacturing of claim 109, wherein the calibration plane is determined by storing the locations of calibration dots in memory.

113. The method of manufacturing of claim 109, wherein the calibration plane is referenced to relate positions of differing views.

114. The method of manufacturing of claim 109, wherein the calibration plane is referenced to perform an interpolation function.

115. The method of manufacturing of claim 109, wherein the calibration plane is referenced to convert pixel values into world values.

116. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light;

providing fixed optical elements to obtain two differing views of the lead;

disposing at least one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using parameters determined during a calibration.

117. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light;

providing fixed optical elements to obtain two differing views of the lead;

disposing at least one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using the locations of a calibration pattern stored in memory.

118. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain a first view of the lead that comprises a segment having a donut shape and a second view of the lead that comprises a segment having a crescent shape;

disposing at least one sensor to obtain the first and second views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using the locations of a calibration pattern stored in memory.

119. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain a first view of the lead that comprises a segment having a donut shape and a second view of the lead that comprises a segment having a crescent shape;

disposing at least one sensor to obtain the first and second views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into an X, Y, and Z world value by using the locations of a calibration pattern stored in memory.

120. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light;

providing fixed optical elements to obtain two differing views of the lead;

disposing a single sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using parameters determined during a calibration.

121. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light that are spectrally diverse from one another;

providing fixed optical elements to obtain two differing views of the lead;

disposing a single sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using parameters determined during a calibration.

122. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light;

providing fixed optical elements to obtain two differing views of the lead;

disposing a single one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using the locations of a calibration pattern stored in memory.

123. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light;

providing fixed optical elements to obtain two differing views of the lead;

disposing a single one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into an X, Y, and Z world value by using the locations of a calibration pattern stored in memory.

124. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead with a ring light and a side light that are spectrally diverse from one another;

providing fixed optical elements to obtain two differing views of the lead;

disposing a single one sensor to obtain the two differing views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using the locations of a calibration pattern stored in memory.

125. A method of manufacturing a ball grid array (BGA) device, the method comprising:

placing an electronic circuit into a BGA package;

making a three dimensional inspection of a lead on the BGA package; and

selecting the combination of the electronic circuit placed inside the BGA package as a produced BGA device based upon the results of the three dimensional inspection;

wherein the three dimensional inspection comprises;

illuminating the lead;

providing fixed optical elements to obtain a first view of the lead that comprises a segment having a donut shape and a second view of the lead that comprises a segment having a crescent shape;

disposing a single sensor to obtain the first and second views of the lead;

transmitting the two differing views of the lead to memory;

determining a first lead reference position in a first view;

determining a second lead reference position in a second view; and

converting the first and second lead reference positions into a world value by using the locations of a calibration pattern stored in memory.