Patent ID: 7838174

Claim:
A method of fabricating a grayscale mask, comprising: preparing a silicon wafer; depositing a layer of Si 3 N 4 directly on the silicon wafer; implanting H + ions into the silicon wafer to form a defect layer; depositing a first layer of SiO x N y directly on the Si 3 N 4 layer; depositing a layer of SRO directly on the first layer of SiO x N y ; patterning a microlens array on the SRO layer; etching the SRO layer to form a microlens array in the SRO layer; depositing a second layer of SiO x N y on the SRO microlens array; CMP to planarize the second layer of SiO x N y ; bonding the planarized SiO x N y to a quartz plate to form a graymask mask; cleaving the silicon wafer along the defect layer; etching to remove silicon from the grayscale mask; etching to remove SiO x N y and Si 3 N 4 from the grayscale mask; and cleaning and drying the grayscale mask.