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.

Phase shift exposing means and production of phase shift mask

Abstract: PURPOSE:To form patterns having high resolution even with a phase shift material having low light transmittance by exposing twice a wafer which is a material to be exposed by using a first phase shift mask formed with light transparent parts and a phase shift part and a second phase shift mask reversed in the positions of the light transparent parts and the phase shift part from the first phase shift mask CONSTITUTION:The first phase shift mask (a) formed with the light transparent parts 12A, 12B and the phase shift part 11 and the second phase shift mask provided with the light transparent part 12 and the phase shift parts 11A, 11B in the positions reversed the positions of the light transparent parts and the phase shift part from the first phase shift mask a are formed The wafer which is the material to be exposed is eventually exposed at uniform light intensity in the final if the wafer is exposed twice by using two sheets of these masks a, b The fluctuation of the pattern widths does not arise and the patterns having high accuracy are obtd even if an inexpensive EB resist having the low light transmittance is used according to the method

Halftone phase shift mask and its manufacturing method

Abstract: PROBLEM TO BE SOLVED: To provide a halftone phase shift mask having the high transmittance of over 6% (9 to 15%), suppressing side etching in a halftone film portion, and having the smooth horizontal plane of a quartz surface, and to provide a method for manufacturing the mask. SOLUTION: The halftone phase shift mask is produced by forming a MoSi-based halftone phase shift film having a film thickness giving a phase difference of ≤135° on a quartz glass substrate and engraving the quartz glass substrate with high perpendicular property and in-plane uniformity by dry etching by magnetic neutral line discharge plasma. The method for manufacturing a halftone phase shift mask includes steps of forming the MoSi halftone phase shift film having a film thickness giving the phase difference of ≤135° on the quartz glass substrate by reactive sputtering and etching the quartz glass substrate using a chromium film as a mask by dry etching by magnetic neutral line discharge plasma with addition of a gas having an effect of protecting a side wall to the process gas. COPYRIGHT: (C)2006,JPO&NCIPI

Optical proximity correction of critical layers in DRAM process of 0.12-μm minimum feature size

Abstract: We studied whether the critical layers of 0.12 micrometer DRAM could be processed with optical lithography techniques assuming ArF excimer laser as a light source. To enhance the aerial image fidelity and process margin, phase shift mask (PSM) patterns as well as binary mask patterns are corrected with in-house developed optical proximity correction (OPC) software. As the result, we found that the aerial image of the critical layers of a DRAM cell with 0.12 micrometer design rule could not be reproduced with binary masks. But, if we use PSM or optical proximity corrected PSM, the fidelity of aerial image, resolution and process margin are so much enhanced that they could be processed with optical lithography.

Practical approach to full-field wavefront aberration measurement using phase wheel targets

Abstract: An automated aberration extraction method is presented which allows extraction of lithographic projection lens' aberration signature having only access to object (mask) and image (wafer) planes. Using phase-wheel targets on a two-level 0/ir phase shift mask, images with high sensitivity to aberrations are produced. Zemike aberration coefficients up to 9 th order have been extracted by inspection of photoresist images captured via top-down SEM. The automated measurement procedure solves a multi-dimensional optimization problem using numerical methods and demonstrates improved accuracy and minimal cross-correlation. Starting with a detailed procedure analysis, recent experimental results for 193-nm projection optics in commercial full field exposure tools are discussed with an emphasis on the performance of the aberration measurement approach.

Mask for exposure and pattern forming method using the mask

Abstract: PROBLEM TO BE SOLVED: To eliminate the influence of the deterioration of a mask material induced by the high-energy exposure light to be case to the mask material of a halftone type phase shift mask and to prolong the service life of a mask for exposure by simple means. SOLUTION: This exposure mask consists of halftone films 303 having dark part regions 301 and bright part regions 302 of the exposure patterns formed on a transparent substrate 300 consisting of quartz, etc. The phase difference between the transmitted light of the dark part regions and the transmitted light of the bright part regions is specified about 180 deg. and the thicknesses of both regions are so set that the ratio of the intensity of the transmitted light of the dark part regions and bright part regions attains 0.03 to 0.15:1.