Flip-chips are aligned by making a fiducial in the "top" chip that is translucent/transparent to light of a wavelength shorter than infrared, and at least one corresponding fiducial in the "bottom" chip. The top-chip fiducial may be made of a transparent or translucent material, its shape may be outlined by an opaque material, or it may be formed by etching through the top chip. The bottom-chip fiducial may be reflective of the light which is transparent/translucent to the fiducial in the top chip, in which case alignment can be achieved by employing at least one video camera which is located above the top chip. Alternatively, the fiducial in the bottom chip may also be transparent/translucent to the light, in which case alignment can be achieved by having the video camera located below the bottom chip. The chips are aligned by aligning the fiducials as seen by the video camera.

 
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