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.

Dense only phase-shift template lithography

Abstract: The steady move towards feature sizes ever deeper in the subwavelength regime has necessitated the increased use of aggressive resolution enhancement techniques (RET) in optical lithography. The use of ever more complex RET methods including strong phase shift masks and complex OPC has led to an alarming increase in the cost of photomasks, which cannot be amortized by many types of semiconductor applications. This paper reviews an alternative RET approach, dense template phase shift lithography, that can substantially reduce the cost of optical RET. The use of simple dense grating templates can also eliminate serious problems encountered in subwavelength lithography including optical proximity and spatial frequency effects. We show that, despite additional design rule restrictions and the use of multiple exposures per critical level, this type of lithography approach can make economic sense depending on the number of wafers produced per critical photomask.

Thick photoresist imaging using a three-wavelength exposure stepper

Abstract: Images formed in thick photosensitive materials are widely used as electroplating molds for micro-electromechanical (MEMS) part and other electronic applications such as bump bonding, thin film heads and multichip module manufacturing. The expansion of traditional microelectronic lithography into very thick photoresists present a technical challenge for stepper manufacturers that have traditionally attempted to optimize resolution and depth of focus for thin photoresist systems. Stepper optics and illumination needs to be re-optimized for the best performance in thick photosensitive materials.

Phase shifting photomask fabrication method

Abstract: A phase shifting photomask fabrication method includes the steps of forming a plurality of opaque patterns on a transparent substrate, forming a first protection layer pattern to cover portions of the opaque patterns and the transparent substrate, etching the transparent substrate to form a transmissive portion using the opaque patterns and the first protection layer pattern as a mask, forming a second protection layer on respective upper surfaces of the transmissive portion, the opaque patterns and the first protection layer pattern, removing a portion of the second protection layer to expose the first protection layer pattern, removing the first protection layer pattern and exposing the opaque patterns and the transparent substrate, growing an aluminum layer using the exposed opaque patterns as a seed to form an aluminum pattern, etching the exposed transparent substrate, anisotropically etching the aluminum pattern, and re-etching the transparent substrate surface exposed by anisotropically etching the aluminum pattern, thereby forming a phase transition region and a phase shifting region.

Double exposure method and photomask for same

Abstract: A double exposure method forms first and second patterns on a cell region and a peripheral circuit region of a wafer, respectively. The method comprises performing a primary exposure through two-beam imaging of 0 order light and −1 order light or +1 order light using a photomask to form the first pattern, and performing a secondary exposure through three-beam imaging of the 0 order light and ±1 order light using the photomask to form the second pattern. Since the double exposure method is performed using the single photomask together with different illuminating systems, exposure time and the number of exposures are both decreased, thereby simplifying the overall process of manufacturing a semiconductor device.

Water-soluble polymer templates for high-resolution pattern formation and materials transfer printing

Abstract: A new class of printing strategies is described for the manufacture of microstructures and nanostructures. This class collectively is referred to as molecular transfer lithography (MxL). The approach is based on the room-temperature fabrication of water-soluble polymer templates by spin casting a polyvinyl alcohol film-forming solution to replicate surface patterns. The templates are useful not only for pattern formation, but also for materials transfer printing, employing a low-cost, convenient, biocompatible chemical approach to high-resolution processing. Results are provided to demonstrate deep submicrometer feature sizes of holes, pillars and lines, 3-D patterns, materials transfer printing of metallic thin films, planarization of wafer topography, and water-soluble polymer templates for 100- and 200-mm wafer patterning. The alignment tooling is discussed and it is shown that MxL can be adapted for use on standard contact aligners with a replacement of the quartz photomask with a water-soluble polymer template to improve resolution without a change of equipment. A high-throughput alignment system for MxL is also discussed. The MxL class of pattern formation and materials transfer printing strategies is differentiated with respect to imprint lithography and soft lithography methods.