Patent ID: 7304775
Filing Date: 2007-12-04
Classification: G03F,G03H

Abstract:
1. A single input beam, division-of-wavefront interference lithography system for generating repetitive patterns suitable for recording by a light sensitive material, comprising: a platform for mounting a workpiece composed of or containing a light sensitive material on its surface; a beam delivery system for dividing a single optical beam into two or more sections, wherein one or more of the sections is reflected, and one of the sections is non-reflected, said beam delivery system comprising: one or more folding mirrors, each folding mirror reflecting a section of the beam and redirecting the reflected section toward said platform such that the reflected section or sections overlap with the non-reflected section, and the sections all interfere with one another to form an optical interference pattern in the vicinity of the workpiece; a support structure on which the one or more folding mirrors are adjustably mounted; means for adjusting the positions and angles of the one or more folding mirrors relative to said platform; and an adjustable apparatus for enlarging and directing the single optical beam toward said platform and folding mirror or mirrors; and an active stabilization system configured to sense and control the relative phases between the divided beam sections such that the position and contrast of the optical interference pattern remains relatively constant over time, said active stabilization system comprising: a feedback apparatus for individually sampling each interfering beam section and indicating in response the relative optical phase between said beam sections, wherein said feedback apparatus comprises a diffractive optical element located next to the workpiece on said platform such that portions of each interfering beam section are redirected through diffraction from the diffractive optical element, and these sampled portions propagate co-linearly, in a direction away from said platform, so that a macroscopic interference pattern between the sampled portions is created and can be observed; a phase modulating apparatus for adjusting the phase of an interfering beam section; and a control system, responsive to the feedback apparatus, for generating a proportionate control signal and providing it to the phase modulating apparatus to hold constant the relative phase between two interfering beam sections.