Abstract: The present invention provides a device which can identify and measure both thermally induced errors and system induced errors in a measuring system, especially a photolithographic system for processing semiconductor wafers. The system includes a stage having associated therewith a first material having a known, relatively high, coefficient of thermal expansion (CTE) and a second material having a significantly lower (preferably zero) CTE in the temperature range in which the system is to be used. The system has a "home" position or location. At least one first indicia mark or set of marks is placed on the first material at a given known (calibrated) distance(s) (at a given known temperature) from the "home" position, and at least one second indicia mark or set of marks is placed on the second material at a given known (calibrated) distance(s) from the home position.

Abstract: Two identical test patterns are overlaid upon each other on a planar substrate of semiconductor material A. Each pattern consists of a plurality of spaced parallel lines. The lines are arranged in two sets of horizontal lines and two sets of vertical lines. The line/space periodicity is known. The lines of the two test patterns are made of two different materials, B and C, respectively. Thus, the target pattern formed by the two test patterns and the substrate has four reflecting regions defined by the different layers in each region: A, AB, AC and ABC. Adjacent the overlaid patterns are four macro-zones each containing a different one of the four layers, A, AB, AC and ABC. Each macro-zone is illuminated by a broad spectrum light, such as that from an incandescent lamp, and the reflected light intensity from each macro-zone is measured. Then, the reflected light intensities from the two sets of horizontal lines are separately measured, as are the reflected intensities from the two sets of vertical lines.

Abstract: This describes an apparatus and method for providing a uniform deposition of a layer from a reactive gas over a large area load by entraining the reactive gas or gases in a carrier gas and sequentially changing the concentration of the reactive gas or gases and the flow rate of the carrier gas as they flow over the load to cause the time integrated deposition rate to be substantially constant over the entire surface of the load, thus depositing a uniformly thick layer over the entire area of the load. These changes in concentration and flow rate shift the center of distribution of the reaction rate across the load such that the time integral of such shifting results in a uniformity of deposition.