Optical Alignment Technique for Chip Placement
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
A system for optically aligning a chip and a substrate prior to bonding comprises a fixed beam splitter located halfway between the chip and substrate but outside the path of movement required for bonding the chip to the substrate, a diffraction grating, and an optical system located between the beam splitter and the grating for reimaging the chip and substrate onto the grating. The fixed beam splitter is preferably comprised of two adjacent prisms, but may also comprise two thin glass plates if a parallel glass plate rotated by 90 degrees relative to the beam splitter is placed along the optical path between the optical system and grating.