Abstract: A method of optically testing the lateral dimensions of a pattern of material disposed on a substrate comprises applying the material to both the main area of the substrate and a test area on the same substrate, and selectively removing the material from both areas on the substrate simultaneously to form respectively the pattern on the main area and a diffraction grating on the test area. The diffraction grating is exposed to a beam of light, and the intensity of two of the diffracted beams is measured to obtain a ratio signal (I.sub.2 /I.sub.1), which is then utilized to determine the lateral dimensional tolerance of the integrated circuit pattern.

Abstract: The method entails vibrating the wafer during the exposure of the photoresist in order to eliminate standing waves which occur in layers parallel to the surface of the photoresist layer and which cause alternately exposed and unexposed layers of the photoresist to be present.

Abstract: An automatic photomask alignment system includes a monochromatic light source, such as a laser, a series of diffraction patterns which are located on a semiconductor substrate and keys which are located on photomasks with which the substrate is to be aligned. A light beam is directed through the key on a photomask onto the diffraction pattern to provide a pattern of light spots whose intensities at various locations are determined by the relative alignment of the mask and the diffraction grating. A feedback arrangement which employs photocells and means for moving the photomasks relative to the substrate provides the alignment of the photomasks with the substrate.

Abstract: A method of optically testing the lateral dimensions of a pattern of material disposed on a substrate comprises applying the material to both the main area of the substrate and a test area on the same substrate, and selectively removing the material from both areas on the substrate simultaneously to form respectively the pattern on the main area and a diffraction grating on the test area. The diffraction grating is exposed to a beam of light, and the intensity of two of the diffracted beams is measured to obtain a ratio signal (I.sub.2 /I.sub.1), which is then utilized to determine the lateral dimensional tolerance of the integrated circuit pattern.