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.

Switchable liquid-crystal phase-shift mask for super-resolution photolithography based on Pancharatnam–Berry phase

Abstract: We present a novel liquid-crystal-based phase-shift mask that utilizes the Pancharatnam–Berry phase for super-resolution photolithography. Using an automated maskless photoalignment technique, we pattern an azobenzene alignment layer in a nematic liquid-crystal cell to fabricate the mask. Since the image is formed by phase cancellation, the minimum feature size is not restricted by the diffraction limit; here, we obtain submicron features. The liquid-crystal properties of the cell allow the mask to be switched on and off by applying a voltage. The cost effectiveness and flexibility of this technique make it a promising new technology for photolithography.

Method for fabricating semiconductor device with loop line pattern structure

Abstract: An alternating phase shift mask with dark loops thereon, a memory array fabricated with the alternating phase shift mask, and a method of fabricating the memory. The dark loops in the mask always separate first regions with 180° phase difference from second regions with 0° phase difference to define active areas or gate-lines in a DRAM chip.

Investigation into a prototype extreme ultraviolet low-n attenuated phase-shift mask

Abstract: The low-n attenuated phase-shift mask can strongly improve extreme ultraviolet imaging performance; it enhances contrast by mask 3D mitigation and a phase-shift effect while simultaneously reducing the required exposure dose. The latter happens because the low-n mask gives optimum contrast at more open mask bias values than its Ta-based counterpart. Here, we experimentally verify the imaging physics of the low-n mask. We show that optimum exposure latitude (EL) with the low-n mask is obtained at more open mask bias values compared to the Ta-based reference mask. This leads to dose reductions exceeding 30% for pitch 38-nm regular contact holes (CHs). Initial local critical dimension uniformity (LCDU) data for hexagonal CHs pitch 38 and 40 nm show 15% LCDU improvement with the low-n mask compared to the Ta-based reference. A 16-nm dense lines show a substantial EL increase and dose reduction with the low-n mask compared to the Ta-based case; this can be even further improved by combining the novel mask absorber with asymmetric illumination. As the low-n masks studied here have absolute reflectivities in the range 8% to 15%, side-lobe printing should be carefully monitored. Initial experimental data for pitch 120-nm CHs and simulations on P32 metal clips, show no signs of side-lobe printing. Careful monitoring of stochastic side-lobe printing for various use cases is recommended.

A novel defect detection optical system using 199-nm light source for EUVL mask

Abstract: Lithography potential expands for 45nm node to 32nm device production by the development of immersion technology and the introduction of phase shift mask. We have already developed the mask inspection system using 199nm wavelength with simultaneous transmitted illumination and reflected illumination optics, and is an effectual candidate for hp 32nm node mask inspection. Also, it has high defect sensitivity because of its high optical resolution, so as to be utilized for leading edge mask to next generation lithography. EUV lithography with 13.5nm exposure wavelength is dominant candidate for the next generation lithography because of its excellent resolution for 2x half pitch (hp) node device. But, applying 199nm optics to complicated lithography exposure tool option for hp2x nm node and beyond, further development such as image contrast enhancement will be needed. EUVL-mask has different configuration from transmitted type optical-mask. It is utilized for reflected illumination type exposure tool. Its membrane structure has reverse contrast compared with optical-mask. This nature leads image profile difference from optical-mask. A feasibility study was conducted for EUV mask pattern defect inspection using DUV illumination optics with two TDI (Time Delay Integration) sensors. To optimize the inspection system configuration, newly developed Nonlinear Image Contrast Enhancement method (NICE) is presented. This function capability greatly enhances inspectability of EUVL mask.

Method of manufacturing phase shift mask blank and method of manufacturing phase shift mask

Abstract: PROBLEM TO BE SOLVED: To provide a phase shift mask blank suitable for a mask for short wavelength exposure light source at a wavelength of 200 nm or shorter and having improved chemical resistance, light resistance and resistance against warm water, and to provide a halftone phase shift mask obtained by using the above phase shift mask blank. SOLUTION: The phase shift mask blank 10 has a light-semitransmitting film 2 having a predetermined transmittance at the wavelength of exposure and comprising nitrogen, metal and silicon as main constituents formed on a transparent substrate 1. After the light-semitransmitting film 2 is formed on the transparent substrate 1, the light-semitransmitting film 2 is acted upon by a high concentration ozone gas. The light-semitransmitting film 2 is patterned to obtain a halftone phase shift mask 20 formed with a light-semitransmitting portion 2a. COPYRIGHT: (C)2008,JPO&INPIT