Minimum Clearance Optical Alignment System
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14
An optical alignment system is provided which achieves minimum clearance between chip and substrate for use in chip-placement tools and the like. The alignment system is made up of an arrangement of fully and partially reflective mirrors which give superimposed views of the chip and the chip site for purposes of aligning the chip prior to chip placement on a substrate. A pair of prisms are employed, the first prism to split and reflect incident light with equal path lengths to the second prism. The second prism functions to direct and reflect the respective beams of split light to and from the chip and chip site over short path lengths back to the first prism whereby the images thereof are superimposed via equal path lengths at the output.