Optical assembly for parallelism measurement, optical apparatus including the same, die bonding system and die bonding method using the same

Abstract

A method of bonding a die to a wafer using a die bonding system measures, using an obtained image showing interference fringes, a parallelism between the die and the wafer. In some embodiments, parallelism and die deformation are detected using interference fringes produced by an optical apparatus of the die bonding system. A parallelism measurement optical apparatus includes a light source, an optical assembly configured to control polarization of a reference light and a measurement light. In some embodiments, the measurement light is sequentially incident on and reflected from a first measurement surface and a second measurement surface that are spaced apart along a vertical direction to face each other, and is emitted to have information on parallelism between the first and second measurement surfaces. In some embodiments, a first polarizer is configured to interfere the reference light and the measurement light emitted from the optical assembly with each other. A light detector is configured to detect an interference signal of lights including the interference fringes.