Browsing by Author "Pan, Shan-Peng"

Now showing 1 - 5 of 5

Grating Pitch Measurement Beyond the Diffraction Limit with Modified Laser Diffractometry
(2011-06-01)
Pan, Shan-Peng
;
Liu, Tzong-Shi
;
Tasi, Min-Ching
;
Liou, Huay-Chung
;
機械工程學系
The demand for accurate measurements of nanostructures is increasing for the microprocesses and nanotechnology used in the semiconductor industry. In this study, we present an improved method for measuring gratings with a pitch size lower than one-half of the laser wavelength by using a modified laser diffractometer (LD). In experiments, the modified LD with a 633nm laser is used to measure a grating with a 288nm pitch size. This result is compared with results measured by both a metrological atomic force microscope and the traditional LD with a 543nm laser. The validity of this method is demonstrated. The difference between the pitch size of 288nm obtained by these three methods is approximately 0.17 nm. (C) 2011 The Japan Society of Applied Physics
Liquid refractometer based on immersion diffractometry
(2007-07-23)
Lu, Sheng-Hua
;
Pan, Shan-Peng
;
Liu, Tzong-Shi
;
Kao, Ching-Fen
;
機械工程學系
This study presents a laser diffractometric refractometer for measuring the refractive index of liquids. The refractive index is determined by rotating a reflection grating that is immersed in the fluid under test, and measuring the first- order Littrow diffraction angle. The Littrow angle is easily detected form the interferogram formed by the diffracted beam from the grating and the reflected beam from the liquid surface. No special cell for liquids is required. The alignment and measuring processes are simpler than those of other refractometers. The results of a feasibility experiment reveal that the accuracy of the proposed approach is about 0.003 for a refractive index of around 1.3. (c) 2007 Optical Society of America.
Method for Determining the Angle in Two Dimension Nanoscale: Pitch Grating
(2011-06-01)
Pan, Shan-Peng
;
Liu, Tzong-Shi
;
Tasi, Min-Ching
;
Liou, Huay-Chung
;
機械工程學系
A two-dimensional (2D) grating is useful for calibrating the accuracy of an electron microscope and atomic force microscope (AFM). An inter laboratory comparison has been carried out for measuring pitches and angles of 2D gratings with 292 and 1000nm pitches using both AFM and an optical diffractometer (OD). The grating angle at the 292nm pitch size was obtained at some of the laboratories by the conventional OD method. However, they could not measure the grating angle when the grating pitch was smaller than (lambda/2) x root 2, where lambda denotes the laser wavelength. We propose a diffraction angle rotation method of grating angle measurements. Using a precision rotary table along with diffractive light, we accurately measure a 2D grating angle for any pitch size larger than lambda/2. (C) 2011 The Japan Society of Applied Physics
Precision Measurement of Sub-50 nm Linewidth by Stitching Double-Tilt Images
(2010)
Pan, Shan-Peng
;
Liou, Huay-Chung
;
Chen, Chao-Chang A.
;
Chen, Jr-Rung
;
Liu, Tzong-Shi
In this paper we present a stitching double-tilt image method (SDTIM) to measure sub-50 nm linewidth and to evaluate the measurement uncertainty. The SDTIM employs a parallel image method using a tilt mechanism to obtain two side scans. Moreover, the stitching method is used for linewidth determination. Experiments were performed by atomic force microscopy (AFM) using an ultrasharp tip, whose radius is smaller than 5 nm. The sample rotation axis is set parallel to the top surface of the sample in order to reduce the problem of measurement position variation. Experimental results show that the developed SDTIM can be used with an uncertainty of less than 5 nm at a confidence level of 95%. (C) 2010 The Japan Society of Applied Physics
Uncertainty Analysis on Precision Measurement for Polystyrene Nanospheres Using Dynamic Light Scattering
(2010)
Pan, Shan-Peng
;
Weng, Han-Fu
;
Lin, Chih-Min
;
Liu, Tzong-Shi
;
機械工程學系
Dynamic light scattering (DLS) is the most commonly used technique for measuring nanosphere sizes. In order to establish the traceability of the DLS method to SI units, relevant parameters have been measured in this study. Several studies have been reported on error sources in DLS. However, these studies lacked a systematic method of analyzing the uncertainty of DLS. In this paper we describe the DLS method and present a measurement uncertainty budget. Monodispersed polystyrene latex (PSL) spheres are selected as reference materials in the uncertainty evaluation. The measured nanosphere sizes are 20, 50, 100, 300, 500, and 1000 nm, among which the measurement results of 100, 300, and 500 nm nanospheres obtained using DLS are compared with those for an electrogravitational aerosol balance (EAB) method. The uncertainties for both methods are calculated, and the results of repeated measurements are presented with confidence levels of 95%. (C) 2010 The Japan Society of Applied Physics