Phase-shift mask

About: Phase-shift mask is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 18058 citations.

Sub-resolution phase shift mask

Abstract: The invention describes the fabrication and use of a sub-resolution phase shift mask. The mask is formed using a single alignment step with all other alignment steps being accomplished by self alignment. This self alignment is made possible by using vertical anisotropic etching of an opaque material layer to form opaque spacers at the pattern edges of phase shifting material. The opaque spacers combine with phase shifting and other opaque regions of the mask to provide improved image resolution and depth of focus tolerance at the surface of an integrated circuit wafer.

Phase shift mask and its production

Abstract: PURPOSE: To provide the phase shift mask which enhances the accuracy of a transferred image at the time of exposing and decreases the damages to a substrate at the time of etching and the process for production of this mask. CONSTITUTION: A phase shifter 11a consisting of the level difference part 13 of a transparent film 4 is formed in the boundary side surface part of a light shielding film 10 and a light transmissive part 20. The light shielding film 10 is constituted of a first light shielding film 2 and second light shielding film 3 varying in etching rate. As a result, the thickness of the level difference part 13 changes gradually from the light shielding film 10 to the light transmissive part 20 and, therefore, the continuous changing of the phase difference of light is possible. The surface of the quartz substrate 1 is etched without giving the damages by the etching. COPYRIGHT: (C)1994,JPO&Japio

Exposing method, phase shift mask to be used therein and production of semiconductor integrated circuit device using the same

Abstract: PURPOSE:To easily form the pattern data of the phase shift mask capable of improving the depth of focus of a transfer exposing surface and the resolution of the patterns. CONSTITUTION:The following stages are provided: A first enlarging stage (107a, 107b) for forming the data on main light transmission patterns by enlarging the width of a repeating pattern in accordance with process conditions without changing the relative position coordinates of the repeating pattern at the time of forming the pattern data on the phase shift mask. A second enlarging stage (108a, 108b) for forming the data on auxiliary light transmission patterns by removing the data on the main light transmission pattern from the data of the patterns obtd. by the enlargement after enlarging the width of the main light transmission patterns of the data state obtd. by the first enlarging stage (107a, 107b) by the prescribed quantity in accordance with the characteristic conditions of a reduction stepper optical system.

Revisiting phase shifting masks in x-ray lithography

Abstract: In this article, we describe a framework for selecting the materials for phase shift masks (PSMs) in x-ray lithography to yield the optimal exposure latitude. Traditional design of PSMs involves choosing the thickness of the material to produce a π phase shift, as in the case of clear phase shifting masks, or to produce the sufficient contrast needed for imaging with a requisite phase shift to improve linewidth control, as in the cases of attenuated phase shifting masks and half-tone phase shifting masks. We instead find the optical constants of a theoretical material that yield optimal exposure latitude, and try to find combinations or alloys of various materials that have the requisite optical constants.

Method of forming photomask of semiconductor device

Abstract: A method of forming a photomask of a semiconductor device includes depositing a first phase shift layer, a light blocking layer, and a second phase shift layer on a transparent substrate, and then a first photoresist pattern is formed to expose a region on an upper surface of the second phase shift layer. Then, the exposed region is etched by using the first photoresist pattern as a mask to form a second phase shift pattern, and the light blocking layer is etched by using the second phase shift pattern as a mask to form a light blocking pattern. Thereafter, a second photoresist pattern is formed on the transparent substrate to define a phase shift region and a light transmitting region. The first phase shift layer is etched by using the second photoresist pattern as a mask to form a first phase shift pattern. Then, the light blocking pattern of the phase shift region is etched to form a phase shift mask pattern.