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.

Device and method for cleaning photomask

Abstract: Disclosed herein is a device and a method of cleaning a photomask, which prevents haze from being generated on a surface of the photomask during a photolithography process. The photomask is heat treated to remove residual ions on a surface thereof and to induce curing and oxidation of Cr and MoSiON layers, thereby preventing diffusion of the ions. Etching of Cr and MoSiON layers due to a cleaning process is suppressed in order to significantly reduce a change in phase and transmissivity of optical properties of Cr and MoSiON.

Near-field sub-diffraction photolithography with an elastomeric photomask

Abstract: Photolithography is the prevalent microfabrication technology. It needs to meet resolution and yield demands at a cost that makes it economically viable. However, conventional far-field photolithography has reached the diffraction limit, which imposes complex optics and short-wavelength beam source to achieve high resolution at the expense of cost efficiency. Here, we present a cost-effective near-field optical printing approach that uses metal patterns embedded in a flexible elastomer photomask with mechanical robustness. This technique generates sub-diffraction patterns that are smaller than 1/10th of the wavelength of the incoming light. It can be integrated into existing hardware and standard mercury lamp, and used for a variety of surfaces, such as curved, rough and defect surfaces. This method offers a higher resolution than common light-based printing systems, while enabling parallel-writing. We anticipate that it will be widely used in academic and industrial productions. Photolithography is an established microfabrication technique but commonly uses costly shortwavelength light sources to achieve high resolution. Here the authors use metal patterns embedded in a flexible elastomer photomask with mechanical robustness for generation of subdiffraction patterns as a cost effective near-field optical printing approach.

Systems, masks, and methods for manufacturable masks using a functional representation of polygon pattern

Abstract: Photomask patterns are represented using contours defined by mask functions or other formats. Given target pattern, contours may be optimized such that defined photomask, when used in photolithographic process, prints wafer pattern faithful to target pattern. Optimized patterns or blocks may be simplified for mask manufacturing.

Versatile maskless microscope projection photolithography system and its application in light-directed fabrication of DNA microarrays

Abstract: We present a maskless microscope projection lithography system (MPLS), in which photomasks have been replaced by a Digital Micromirror Device type spatial light modulator (DMD™, Texas Instruments). Employing video projector technology high resolution patterns, designed as bitmap images on the computer, are displayed using a micromirror array consisting of about 786 000 tiny individually addressable tilting mirrors. The DMD, which is located in the image plane of an infinity corrected microscope, is projected onto a substrate placed in the focal plane of the microscope objective. With a 5× [0.25 NA (numerical aperture)] Fluar microscope objective, a fivefold reduction of the image to a total size of 9mm2 and a minimum feature size of 3.5μm is achieved. The ultrahigh pressure lamp of a video projector is a cheap, durable, and powerful alternative to the mercury arc lamps commonly used in lithography applications. The MPLS may be employed in standard photolithography. We have successfully produced patterns i...

Printability and repair techniques for DUV photomasks

Abstract: Intention of this paper is to discuss some issues resulting from increasing requirements on mask making for 0.25 micrometer technology and below. The key question to be discussed is: How can zero defects masks be guaranteed in future and what efforts are needed to reach that goal. Using state of the art equipment two photomasks were manufactured with typical sized and shaped programmed defects. First, criteria is discussed to characterize the printability of mask defects. Key element is the aerial image measurements system MSM100/AIMS. As a result it was found that the criteria strongly depends on the principle shape of the considered pattern. It is shown that the standard criteria used for mask repair, i.e. relative change of the maximum feature image intensity, is only applicable in case of best dose and best focus. The results were used to improve the performance of an attenuated DUV phase-shifting-mask (aPSM). Various repair techniques have been studied. As a result it can be concluded that high quality mask repairs are available which allow the fabrication of defect free aPSM.