Showing papers on "Photomask published in 1971"

Method of defining a detailed pattern on a surface of a body

Abstract: A DETAILED PATTERN ON A PHOTOMASK IS DEFINED, IN REDUCED SIZE, ON A SURFACE OF A BODY BY A NOVEL PHOTOLITHOGRAPHIC PROCESS EMPLOYING TWO SUCCESSIVE FRESNEL DIFFRACTION PRINTINGS. THE SURFACE OF THE BODY IS PROVIDED WITH THREE LAYERS, A LOWER PHOTORESIST, A METAL, AND AN UPPER PHOTORESIST, RESPECTIVELY. THE UPPER PHOTORESIST IS EXPOSED WITH A FRESNEL DIFFRACTION PATTERN OF THE DETAILED PATTERN FOR A TIME TO ACTIVATE IT WITH ONLY THE GREATER INTENSITIES OF LIGHT OF THE FRESNEL DIFFRACTION PATTERN. THE DEVELOPED UPPER PHOTORESIST DEFINES THE DETAILED PATTERN, IN REDUCED SIZE, ON THE LAYER OF METAL. THE LOWER PHOTORESIST IS SIMILARLY EXPOSED ND ACTIVATED THROUGH AN ETCHED MASK OF THE LAYER OF METAL, AS DEFINED BY THE UPPER PHOTORESIST. WHEN DEVELOPED, THE LOWER PHOTORESIST DEFINES THE DETAILED PATTERN, STILL FURTHER REDUCED IN SIZE, ON THE SURFACE OF THE BODY.

Method of projection printing photoresist masking layers, including elimination of spurious diffraction-associated patterns from the print

Abstract: A substrate covered with photoresist is positioned in a parallel, spaced, fixed relationship to a photomask to form a photomask assembly. Then, the photoresist is exposed to a diffraction image of the photomask by projecting collimated light through the photomask. The diffraction image comprises a primary image and a spurious, diffraction-associated secondary image. The light is projected with an oblique orientation to the photomask. The oblique orientation is varied during the exposing to selectively prevent the secondary image from resulting in the uncovering of corresponding areas of the substrate upon development. Then the photoresist is developed to uncover selected areas of the substrate.

Method of selective multilayered etching

Abstract: A method for selectively etching a workpiece to different depths with a single multicolored photomask. In particular, the multicolored mark is used to selectively expose separate layers of photoresist. The separatelayers of photoresist are developed, and then selectively removed after performing a desired masking function. This method is particularly useful in fabricating resistor-conductor patterns for integrated circuits.

Method of making photomasks of the type used in the fabrication of microelectronic circuits

Abstract: FIIG-01 A METHOD OF MAKING PHOTOMASKS CONTAINING LINES OF VARIOUS WIDTHS FOR USE IN THE FABRICATION OF MICROELECTRONIC CIRCUITS. THE METHOD UTILIZES A TWO-STEP DEVELOPMENT PROCESS TO ESSENTIALLY ELIMINATE THE EFFECTS OF OPTICAL DIFFRACTION AND PROVIDE BOTH THICK AND THIN LINES HAVING A HIGH DEGREE OF ACUTANCE, DENSITY AND DIMENSION CONTROL. THE FIRST DEVELOPMENT STEP UTILIZES A LOW-CONTRAST DEVELOPER TO PRODUCE A NEARLY CONSTANT-DENSITY IMAGE OVER A WIDE EXPOSURE LATITUDE. THE SECOND STEP EMPLOYS A HIGHCONTRAST DEVELOPER WHICH ENHANCES THE DENSITY IN AREAS DEVELOPED BY THE FIRST STEP.