Reflection by internal total reflection holography-Automatic aberration correction in refractive projection optical system

摘要

The present invention relates to a TTL alignment device for a stepper or a scanner for fabricating a semiconductor device, which performs a TTL alignment for correcting chromatic aberration by generating a phase conjugate wave by a total internal reflection holography method /RTI Among the holography methods, the internal total reflection type holography has advantages in that it has a simple structure and is advantageous in the alignment system configuration, and the influence of the reference light on the optical system is small, so that the influence of the semiconductor exposure equipment on the projection optical system is small. Based on this technique, the wafer stepper using the light of the ArF excimer laser as an exposure light source is directly aligned with the position of the reticle and the wafer, and an incident refraction optical system 102 for refracting the pattern of the mask by the exposure light source, (103) and a polarization beam splitter (104); A concave reflecting mirror 105 and an output optical system 106 for reducing and projecting the pattern onto the wafer; A TTL aligning means that is incident from the light source of the argon laser 110 through the fiber; The alignment light 111 projected into the reflection-refraction system by the TTL alignment means is divided into a wafer alignment light 112 and a reticle alignment light 114 to be projected onto the reticle 108 and the wafer 107, A light splitter 104; And a single mode fiber 202 for transferring the alignment light from the argon laser 110 to the internal total reflection type holographic TTL alignment means. The TTL alignment means may include an internal total hologram alignment system 200 .