A Fabry-Perot resonator, also called a Fabry-Perot cavity, is a spectroscopic device of extremely high resolving power and is a very useful tool for alignment of mask and wafer for the multiple exposures necessary to make a semiconductor integrated circuit. When a Fabry-Perot cavity is used for alignment in a multi-exposure imaging procedure, the cavity itself must be very accurately aligned for each exposure. For proper alignment system operation, it is necessary that one of the mirrors of the resonant cavity be fixed with respect to the mask, and the other mirror be fixed with respect to the wafer. This invention provides a mechanical system and method to maintain the alignment of a Fabry-Perot cavity for each exposure. This invention describes a technique in which the Fabry-Perot cavity is transported from one exposure area to the next without need for realignment. After an exposure is completed, the mechanical link between one of the mirrors and the mask is designed to be decoupled while the mask and wafer are relatively displaced for the next exposure. As a result, during the displacement, the relative distance between the optical mirrors of the Fabry-Perot cavity is maintained, as well as the relative orientation. After the displacement is completed, the mechanical link is then re-established so that the alignment system performs in an identical manner for each exposure site.
A system and method for determining information about an assay. In one embodiment the method includes positioning a filter assembly, having an assay disposed on its surface, relative to a light source such that light from the light source is incident on the filter assembly and at least a portion of the light incident on the filter assembly is reflected from the filter assembly, illuminating the filter assembly with light from the light source, receiving light reflected from the filter assembly in an optical element, analyzing one or more characteristics of the light received in the optical element to determine information about a reaction in the assay, wherein a reaction in the assay results in a change of one or more characteristics of the light received from the filter assembly. In another embodiment, a system for analyzing an assay, comprises a structure in a resonating cavity configured to receive a filter assembly having an assay disposed on a first surface thereof such that the assay is positioned outside the resonating cavity, a light source positioned in the resonating cavity to communicate light to a second surface area of the filter assembly disposed in the resonating cavity, and an analysis system configured to receive light emitted from the filter assembly and detect information about a reaction in the assay based on one or more characteristics of the light.
