Showing papers by "Satoshi Nagai published in 2008"

Influence of pellicle on hyper-NA imaging

Abstract: In the case of hyper-NA (NA>1) imaging with the lens magnification keeping 1/4, the angle of light incidence on pellicle becomes bigger. For example, it is up to 19 degrees for NA=1.3 lens. It is already known that the effect of multiple reflections of the light inside the pellicle film becomes obvious, in that the effect contains transmission variation across the light incidence angle on the pellicle. For normal pellicle, transmission of oblique incidence light is lower than the normal incidence light and the difference is about 10% as intensity changes. And pellicle thickness error affects the transmission characteristics. Thus, pellicle thickness error causes change of iso-dense bias (or optical proximity effect; OPE) and dense line CD variation. Specs for CD uniformity in below half pitch (hp) 45nm imaging become tighter, and therefore, pellicle should not be a new root cause of CD error. The solutions for the issue are (1) tighter specs for pellicle thickness or (2) selection of optimal pellicle thickness. The latter is more effective for suppressing CD variation across the exposure field than the former. In our paper, we describe the pellicle effect for through-pitch imaging including below hp45 nm dense L/S using hyper-NA lens. We discuss pellicle thickness optimization for better CD uniformity and the results of simulation for some pellicle conditions.

Immersion resist process for 32-nm node logic devices

Abstract: Key issues of resist process design for 32nm node logic device were discussed in this paper. One of them is reflectivity control in higher 1.3NA regime. The spec for the reflectivity control is more and more severe as technology node advances. The target of reflectivity control over existent substrate thickness variation is 0.4%, which was estimated from our dose budget analysis. Then, single BARC process or stacked mask process (SMAP) was selected to each of the critical layers according to the substrate transparency. Another key issue in terms of material process was described in this paper, that is spin-on-carbon (SOC) pattern deformation during substrate etch process. New SOC material without any deformation during etch process was successfully developed for 32nm node stacked mask process (SMAP). 1.3NA immersion lithography and pattern transfer performance using single BARC

Method and apparatus for eddy current flaw detection testing

Abstract: PROBLEM TO BE SOLVED: To provide an eddy current flaw detection testing method and an eddy current flaw detection testing apparatus having high accuracy in length evaluation and high versatility by using physical phenomena specific to an eddy current flaw detection testing method. SOLUTION: A defect 15 in a surface to be inspected is detected through the use of a probe 11 having both a first coil 12 of which the direction of the center axis matches the direction of a normal of the surface to be inspected and a second coil 13 of which the direction of the center axis matches the direction of a normal of the surface to be inspected and which is arranged with a prescribed center-to-center distance d1 with the first coil 12 to evaluate the length L of the defect in the eddy current flaw detection testing method. An output voltage distribution caused by the defect in the surface to be inspected is obtained by the probing of the probe 11 to detect two maximal values which have appeared in the output voltage distribution. The length d2 between the two detected maximal values is computed. A result of the addition of the computed length d2 between the maximal values to the center-to-center distance d1 of the first coil 12 and the second coil 13 is evaluated as the length L of the defect in the surface to be inspected. COPYRIGHT: (C)2010,JPO&INPIT

Photomask unit, exposure method and method for manufacturing semiconductor device

Abstract: PROBLEM TO BE SOLVED: To provide a photomask unit having an optimized pellicle. SOLUTION: The photomask unit 10 comprises a mask substrate 20 having a pattern arranged with a pitch P and a pellicle 30 protecting the mask substrate. The pellicle is configured to maximize the transmittance for incident light at an incident angle θ defined by sinθ=λ/(2P), wherein λ represents the wavelength of the incident light. COPYRIGHT: (C)2008,JPO&INPIT