Abstract: A method of monitoring a light integrator of a photolithography system, wherein the photolithography system comprises a light source for illuminating different fields of a photosensitive layer and a light integrator for measuring the actual exposure doses of the illuminated fields, comprises the step of illuminating different fields of the photosensitive layer in succession. In each illumination step the actual exposure dose is measured by means of the light integrator, the actual exposure time (actualTime) is controlled so that the actual exposure dose to which a field of the photosensitive layer is exposed corresponds to a desired exposure dose, and the actual exposure time (actualTime) is fed to a monitoring system for in-line monitoring the light integrator during illumination of the fields.

Abstract: A method for in-line monitoring a lens controller of a photolithography system in which a plurality of wafers of a lot are processed in succession and which includes a lens for projecting a mask pattern on the wafers and a lens controller for correcting magnification of the lens includes the steps of printing a circuit pattern on each of the wafers of the lot by projecting a mask pattern on the wafers by means of a lens, determining a shot magnification value for a sample of the wafers, and continuously monitoring the variation of the shot magnification values, wherein a variation of the shot magnification values exceeding a first predetermined value indicates a failure of the lens controller.

Abstract: A method of monitoring a light integrator of a photolithography system, wherein the photolithography system comprises a light source for illuminating different fields of a photosensitive layer and a light integrator for measuring the actual exposure doses of the illuminated fields, comprises the step of illuminating different fields of the photosensitive layer in succession. In each illumination step the actual exposure dose is measured by means of the light integrator, the actual exposure time (actualTime) is controlled so that the actual exposure dose to which a field of the photosensitive layer is exposed corresponds to a desired exposure dose, and the actual exposure time (actualTime) is fed to a monitoring system for in-line monitoring the light integrator during illumination of the fields.

Abstract: Disclosed herein is an automatically controlled weigh feeding system including a container prefilled with a substance, a device for discharging the substance from the container at a controllable rate, apparatus for weighing the container and its contents and for producing an electrical signal proportional to that weight, apparatus actuated by the electrical signal for controlling the discharge of the substance from the container, and a detector circuit actuated by the electrical signal for producing an output which is responsive to predetermined excessive excursions of the electrical signal for locking the discharge control apparatus against deviation during the time of the excessive excursion. .Iadd.