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A calibration and part inspection method for the inspection of ball grid array, BGA, devices. Two 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 reflectiv

A calibration and part inspection method for the inspection of ball grid array, BGA, devices. Two 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 first 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 a second camera and a second additional mirror or prism located below the bottom plane of the reticle reflects the opposite side view of the reticle pattern mask through prisms or mirrors into a second 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 the two cameras. The scene of the part can thus be triangulated and the dimensions of the BGA are determined.

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What is claimed is: 1. A method of manufacturing a ball array device, the method comprising: making a three dimensional inspection of a lead on the ball array device with the ball array device being positioned in a fixed optical system; and selecting the ball array device as a produced ball array d

What is claimed is: 1. A method of manufacturing a ball array device, the method comprising: making a three dimensional inspection of a lead on the ball array device with the ball array device being positioned in a fixed optical system; and selecting the ball array device as a produced ball array device based upon the results of the three dimensional inspection; wherein the three dimensional inspection comprises: illuminating the ball array device; taking a first image of the ball array device with a first camera disposed in a fixed focus position relative to the ball array device to obtain a characteristic circular doughnut shape image from at least one ball; taking a second image of the ball array device with a second camera disposed in a fixed focus position relative to the ball array device to obtain a side view image of the at least one ball; 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. 2. The method of manufacturing of claim 1, wherein the second image comprises a segment having a crescent shape. 3. The method of manufacturing of claim 1, 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. 4. The method of manufacturing of claim 1, 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. 5. The method of manufacturing of claim 1, wherein the pre-calculated calibration plane is defined through measuring a calibration pattern. 6. The method of manufacturing of claim 1, wherein the taking a second image further comprises interposing a mirror between the ball array device and the second camera. 7. The method of manufacturing of claim 1, wherein the second image is obtained at a low angle of view. 8. The method of manufacturing of claim 1, wherein the first camera and the second camera are fixed at different angles relative to the calibration plane. 9. The method of manufacturing of claim 1, wherein the processing measurements from the first image and the second image comprises employing grayscale edge detection to locate ball positions. 10. The method of manufacturing of claim 1, wherein the illuminating the ball array device comprises employing diffuse illumination. 11. The method of manufacturing of claim 1, wherein the ball array device comprises a ball grid array device. 12. The method of manufacturing of claim 1, wherein the ball array device comprises a bump on wafer device. 13. The method of manufacturing of claim 1, wherein illuminating is achieved using a single light source. 14. The method of manufacturing of claim 1, wherein illuminating is achieved using more than one light source. 15. The method of manufacturing of claim 14, wherein the more than one light sources used are spectrally diverse from one another. 16. A method of manufacturing a ball array device, the method comprising: making a three dimensional inspection of a lead on the ball array device with the ball array device being positioned in an optical system; and selecting the ball array device as a produced ball array device based upon the results of the three dimensional inspection; wherein the three dimensional inspection comprises: illuminating the ball array device to produce reflections; taking a first image of the reflections with a first camera disposed in a first fixed position to obtain a circular doughnut shape image of the ball array device; taking a second image of the reflections with a second camera disposed in a second fixed position non-parallel to the first fixed position to obtain a side view of the ball array device; and processing measurements from the first image and the second image to calculate a three dimensional position of at least one ball using a triangulation method with reference to a pre-calculated calibration plane. 17. The method of manufacturing of claim 16, wherein the second image comprises a segment having a crescent shape. 18. The method of manufacturing of claim 16, 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. 19. The method of manufacturing of claim 16, wherein the pre-calculated calibration plane is defined through measuring a calibration pattern. 20. The method of manufacturing of claim 16, wherein the taking a second image further comprises interposing a mirror between the ball array device and the second camera. 21. The method of manufacturing of claim 16, wherein the processing measurements from the first image and the second image comprises employing grayscale edge detection to locate ball positions. 22. The method of manufacturing of claim 16, wherein the processing measurements from the first image and the second image comprises employing grayscale edge detection to locate ball positions. 23. The method of manufacturing of claim 16, wherein the illuminating the ball array device comprises employing diffuse illumination. 24. The method of manufacturing of claim 16, wherein the ball array device comprises a ball grid array device. 25. The method of manufacturing of claim 16, wherein the ball array device comprises a bump on wafer device. 26. The method of manufacturing of claim 16, wherein illuminating is achieved using a single light source. 27. The method of manufacturing of claim 16, wherein illuminating is achieved using more than one light source. 28. The method of manufacturing of claim 27, wherein the more than one light sources used are spectrally diverse from one another. 29. A method of manufacturing a ball array device, the method comprising: making a three dimensional inspection of a lead on the ball array device with the ball array device being positioned in an optical system; and selecting the ball array device as a produced ball array device based upon the results of the three dimensional inspection; wherein the three dimensional inspection comprises: illuminating the ball array device; taking a first image of the ball array device with a first camera disposed in a first fixed position relative to the ball array device to obtain a circular doughnut shape view of the ball array device, wherein the first camera includes a charged coupled device array; taking a second image of the ball array device with a second camera disposed in a second fixed position non-parallel to the first fixed position to obtain a side view of the ball array device, wherein a fixed mirror is interposed to reflect light between the ball array device and the second camera, and wherein the second camera includes a charged coupled device array; and processing measurements from the first image and the second image to calculate a three dimensional position of at least one ball using a triangulation method with reference to a pre-calculated 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. 30. The method of manufacturing of claim 29, wherein the second image comprises a segment having a crescent shape. 31. The method of manufacturing of claim 29, wherein the pre-calculated calibration plane is defined through measuring a calibration pattern. 32. The method of manufacturing of claim 29, wherein the processing measurements from the first image and the second image comprises employing grayscale edge detection to locate ball positions. 33. The method of manufacturing of claim 29, wherein the illuminating the ball array device comprises employing diffuse illumination. 34. The method of manufacturing of claim 29, wherein the ball array device comprises a ball grid array device. 35. The method of manufacturing of claim 29, wherein the ball array device comprises a bump on wafer device.