Photomask

About: Photomask is a research topic. Over the lifetime, 7917 publications have been published within this topic receiving 54524 citations. The topic is also known as: photoreticle & reticle.

Arrays of Nanoscale Lenses for Subwavelength Optical Lithography

Abstract: Poly(ethylene glycol) (PEG) polymer lens arrays are made by using dip-pen nanolithography to deposit nanoscale PEG features on hydrophobically modified quartz glass. The dimensions of the PEG lenses are controlled by tuning dwell time and polymer molecular weight. The PEG polymer lenses on the quartz substrate act as a phase-shift photomask for fabricating subwavelength scale features, ∼100 nm in width. Depending upon UV irradiation time during the photolithography, the photoresist nanostructures can be transitioned from well-shaped (short time) to ring-shaped (long time) features. The technique can be used to pattern large areas through the use of cantilever arrays.

Illumination device for projection system and method for fabricating

Abstract: A masking aperture for a photomask illumination system provides controlled on-axis and off-axis illumination. The masking aperture has a dithered pattern of pixels. The intensity of the pattern controls the illumination of the photomask. The masking aperture pattern defines one or more zones of illumination. Zones comprise elements that are patterned in accordance with a selected wavelength of incident light to diffract the incident light into an illumination pattern for illuminating a photomask. Each of the elements is constructed with a matrix of pixels. In the preferred embodiment the array of pixels is 8×8. The number of elements is generally greater than 3×3.

Method and apparatus for redressing defective photomask

Abstract: A method and apparatus for repairing defect portions of a photomask. A complex material from which a light shading material can be deposited is applied over the photomask. A white (blank) defect region is irradiated with a continuous wave laser light beam projected in a slit-like light image to thereby convert the complex material into the shading material. After washing, a half-deposited portion formed in a peripheral portion of the light shading region is further deposited by a post-baking process. Those portions of the light shading film which depart from the desired mask pattern are removed together with black (solid) defect portion originally present in the photomask through irradiation with a pulse laser light beam. The pulse laser is constituted by a Dye-laser, while the continuous wave laser is constituted by an Ar-laser. A specific half-mirror which transmits therethrough Ar-laser light while reflecting Dye-laser light is displaceable provided. The white and the black defects are selectively centered on a same optical axis of an optical projection system including a slit and a condenser lens, whereby the white and the black defect portions are each removed through irradiation with the associated laser light projected thereto in a slit-like light image through the same optical projection system.

Fabrication of domain-inverted gratings in MgO:LiNbO3 by applying voltage under ultraviolet irradiation through photomask at room temperature

Abstract: A new and simple fabrication method of domain-inverted gratings in MgO:LiNbO/sub 3/ is demonstrated. It was found that ultraviolet (UV) light irradiation reduces the voltage for inversion. Domain-inverted gratings of /spl sim/15 /spl mu/m period were fabricated by voltage application at room temperature under irradiation of UV light periodically-patterned using a photomask.

Phase defect inspection by differential interference

Abstract: Photomask pattern inspection using transmitted light and/or reflected light is commonly used for Die to Die or Die to Database comparison method. We have applied the differential interference contrast method to phase defect inspection for alternating phase shifting mask (Alt-PSM). The key parameters for optics are resident phase in an interferometer, shearing direction and distance between two spots, which are determined by Nomarski prism design. Firstly, we studied defect image contrast by simulation. Chrome edge defects are more detectable than isolated center defects from the simulation result. Next, we configured a reflective type, differential interference optics using an Ar ion laser as a light source. A test mask having 70-degree phase defects on 520, 600, and 720 nm CD are inspected. Edge defects down to 520nm CD were detectable compared with conventional reflective method.