Abstract
The purpose of this study is to set up a 3D X-ray image reconstruction technique to inspect the defect of BGA joints of a double-side circuit board. Via nondestructive X-ray inspection, we can know the inside structure of BGA joint. Inspecting BGA joints by using the Computed Tomography(CT) method can help us to get the clear inner information, however one of the disadvantages of CT is that it takes long time to inspect due to so many image of different projective angles are needed. And the other is that the use of CT to inspect large or flat object like circuit board is limited because the full access around the object is necessary due to the CT algorithm. Nowadays the common inspection methods used are radiography and laminography, nevertheless, their handicap is that the reconstruction images are not clear enough. This study combines the laminography and CT algebraic reconstruction technique to reconstruct the vertical inner cross section image by using fewer images of different projective angles. Industrial inspection demands to construct the inner structure of an object fast and accurately, so in this study, the parameters which influence the reconstruction quality and speed are studied. Furthermore, in order to reduce the reconstructive computation time, we reduce the reconstructive image size by separating upper and lower images of the double-side circuit board. Thus we can reconstruct the BGA joints images.