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.

Vacuum ultraviolet transmitting silicon oxyfluoride lithography glass

Abstract: High purity silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed with the silicon oxyfluoride glass having a preferred fluorine content < 0.5 weight percent. The inventive silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a 'dry,' silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1x1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Using patterns in microfiche as photomasks in 10-mu m-scale microfabrication

Abstract: Microfiche has been used as the photomask in 1:1 contact photolithography to generate structures of photoresist with features as small as 10 μm. Optical reduction of images that were printed by a high-resolution image setter on transparent polymer sheets generated patterns in microfiche. The photoresist patterns generated using microfiche as the photomask are useful in the fabrication of elastomeric stamps/molds/membranes for soft lithography. Four test structures fabricated using microfiche as photomask and soft lithography are used to evaluate the utility and resolution of this technique.

Method for correcting critical dimension variations in photomasks

Abstract: A method for compensating for critical dimension (CD) variations of pattern lines of a wafer, by the correcting the CD of the corresponding photomask. The photomask comprises a transparent substrate having two substantially opposite surfaces, a first back surface and a second front surface on which front surface an absorbing coating is provided, on which the pattern lines were formed by removing the coating at the pattern lines. The method comprises: determining CD variations across regions of a wafer exposure field relating to the photomask; and providing Shading Elements (SE) within the substrate of the photomask in regions which correlates to regions of the wafer exposure field where CD variations greater than a predetermined target value were determined, whereby the shading elements attenuate light passing through the regions, so as to compensate for the CD variations on the wafer and hence provide and improved CD tolerance wafer.

Intelligent photomask disposition

Abstract: A method for determining whether a defect that is detected by photomask inspection will adversely affect a semiconductor device, such as a wafer. The method has the ability of relating defect specifications directly to device performance and wafer yields, and assessing the impact of combining the defect with the critical dimension error using standard inspection tools. More specifically, the method includes the steps of: inspecting the photomask for defects; measuring the size and location of the defects relative to features on the photomask; classifying the defects by type of defect; assigning an equivalent mask critical dimension error (EME) value to each of the features based on size, location and type of defect; assigning a total mask error to each of the features by adding EME values to each defect impacting the features; and comparing the equivalent critical dimension error to a mask critical dimension error tolerance to determine whether the defects adversely affect the performance of the semiconductor device.

Application of alternating phase-shifting masks to 140-nm gate patterning: linewidth control improvements and design optimization

Abstract: In this paper we show that the problem of intrafield line width variations can be effectively solved through a novel application of alternating phase-shifting mask (PSM) technology. To illustrate its advantages, we applied this approach to produce 140 nm transistor gates using DUV (248 nm wavelength, KrF) lithography. We show that: systematic intrafield line width variations can be controlled to within 10 nm (3 (sigma) ), and variations across the wafer held to within 15 nm (3 (sigma) ), with a target k1 factor of K1 equals 0.237 (140 nm target gate lengths).