scholarly journals Double diffraction grating alignment method using checker grating. (1st report). Alignment accuracy evaluation.

1989 ◽  
Vol 55 (7) ◽  
pp. 1235-1240
Author(s):  
Mitsuo TABATA ◽  
Toru TOJO
Keyword(s):  
Diffraction Grating ◽  
Alignment Accuracy ◽  
Accuracy Evaluation ◽  
Alignment Method ◽  
Double Diffraction

A Precision Alignment Method to <100> Direction on (110) Silicon Wafer

2001 ◽  
Author(s):  
Fan-Gang Tseng ◽  
Kai-Chen Chang
Keyword(s):  
Silicon Wafer ◽  
Crystal Orientation ◽  
Silicon Wafers ◽  
Innovative Approach ◽  
Alignment Accuracy ◽  
Alignment Method

Abstract This paper proposes a novel pre-etch method to determine the lt;100gt; direction on (110) silicon wafers for bulk etching. Series of circular windows were arranged in an arc of radius 48.9 mm, and bulk-etched to form hexagonal shapes for crystal orientation finding. The corners of the hexagons can be used as an alignment reference for the indication of the lt;100gt; direction on (110) silicon wafers. This innovative approach has been demonstrated experimentally to give an orientation-alignment accuracy of ± 0.03° for (110) wafers with 4-inch diameter.

Mini-Nano-Displacement Measurement with Double Diffraction Grating

2011 ◽  
Vol 230-232 ◽  
pp. 1159-1163 ◽  
Author(s):  
Min Lan Jiang ◽  
Fu Peng Li ◽  
Xiao Dong Wang
Keyword(s):  
Diffraction Grating ◽  
Deflection Angle ◽  
Optical Measurement ◽  
Mathematic Model ◽  
Displacement Measurement ◽  
Fourier Optics ◽  
Light Path ◽  
Double Diffraction ◽  
Analysis Method ◽  
Optical Distance

Based on Doppler and Fourier optics analysis method, analyzed the configuration of double diffraction grating, and built its non-contact optical measurement mathematic model. And built double diffraction grating interference displacement measurement system, the design of double diffraction light path can compensate the deflection angle of grating moving, greatly improved tolerance of grating’s deflection. The compact and micro configuration of its light path, shorten optical distance, improving system’s environment anti-interference ability. Experimental resulting show, within 20nm displacement measurement, and<50mm/sec measurement speed, the system resolution is 1nm and measurement precision is less than 30nm.

Alignment accuracy evaluation of the X-ray stepper SS-1 for processed wafers

1997 ◽  
Vol 35 (1-4) ◽  
pp. 537-540 ◽  
Author(s):  
M. Suzuki ◽  
M. Fukuda ◽  
H. Tsuyuzaki
Keyword(s):  
Alignment Accuracy ◽  
Accuracy Evaluation ◽  
X Ray

scholarly journals Alignment accuracy evaluation of X-ray lithography system SR-1.

1985 ◽  
Vol 51 (5) ◽  
pp. 1040-1046
Author(s):  
Kimiyoshi DEGUCHI ◽  
Nobuyuki TAKEUCHI ◽  
Hiroo KINOSHITA
Keyword(s):  
Alignment Accuracy ◽  
Accuracy Evaluation ◽  
X Ray ◽  
Lithography System

Integrated Navigation on Vehicle Based on Low Cost MEMS SINS/GNSS using LS-SVM

2021 ◽  
Author(s):  
Ning Liu ◽  
Hui Zhao ◽  
Zhong Su ◽  
Likang Qiao ◽  
Yiping Dong
Keyword(s):  
Low Cost ◽  
Dynamic Error ◽  
Alignment Accuracy ◽  
Integrated Navigation ◽  
Alignment Method ◽  
Initial Alignment ◽  
State Equations ◽  
Mems Gyroscopes ◽  
Motion Characteristics ◽  
Attitude Alignment

Abstract The high-precision initial alignment time for the MEMS SINS/GNSS combination system is too long, and it is difficult to ensure the flexible navigation of existing low-cost vehicles. A LS-SVM-assisted fast alignment method is proposed, which uses MEMS gyroscopes, accelerometers and dual-antenna satellite receivers to achieve fast alignment under MEMS SINS/GNSS. Based on the analysis of traditional coordinates and strapdown inertial navigation, the dynamic error model is given. The self-aligned frame of LS-SVM is proposed. At the same time, the EKF filter for training is designed and the motion characteristics of the car body are selected. The state equations and observations, using the EKF to train the LS-SVM model, ultimately achieve fast alignment. Finally, the proposed method is simulated and tested. The final attitude alignment accuracy is better than 0.2° and the alignment time is 10s. Compared with the EKF alignment method under the traditional direct transfer alignment, the alignment accuracy and the alignment time are significantly improved, which can meet the requirements of low-cost vehicle flexibility.

scholarly journals A Fast and High-Accuracy Compass Alignment Method to SINS with Azimuth Axis Rotation

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Xixiang Liu ◽  
Xiaosu Xu ◽  
Yiting Liu ◽  
Lihui Wang
Keyword(s):  
Navigation System ◽  
Calculation Method ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Low Frequency ◽  
High Accuracy ◽  
Alignment Accuracy ◽  
Alignment Method ◽  
Axis Rotation ◽  
Sensor Errors

Azimuth axis rotating modulation was introduced to improve the alignment accuracy of strapdown inertial navigation system (SINS) through compass algorithm, in which the limit accuracy was determined by equivalent sensor errors in the eastern and northern direction. In this modulation, horizontal sensor errors were modulated into zero mean periodic variables. Furthermore, two methods were introduced to ensure alignment accuracy and speed: (1) shortened rotating cycle and redesigned compass parameters were selected to eliminate or ease the amplification to low-frequency senor error inputs in compass loop caused by rotation and (2) a data repeated calculation method was designed to shorten prolonged alignment time caused by the above redesigned parameters. Based on a certain SINS, turntable test proves that alignment accuracy and time were significantly improved and slightly shortened in comparison with the classical compass alignment.

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