SPECTRAL IMAGING VIEWER SOFTWARE MANUAL

Transcription

1 103 Quality Circle, Suite 215 Huntsville, AL Phone: (256) Fax: (256) Website: SPECTRAL IMAGING VIEWER SOFTWARE MANUAL 2012 All rights reserved. AxoScan, AxoStep, AxoView, Axometrics and the Axometrics logo are trademarks of

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3 Please read these instructions completely and carefully before operating the Instrument. If you have any questions, or experience any difficulties, please contact Axometrics or the representative from whom the instrument was purchased. iii

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5 CONTENTS 1 Introduction Instrument Files Directory spectrum measurement Acquire Imaging Spectrum turn on control unit Wavelength settings Open live view and set initial exposure time Baseline Measure Analyze Spectrum Choose single image single point spectrum Avearged area spectrum Show spectrum in CIE chromoticity coordinate Frequency analysis Set Refractive Index Use Cursor Tool to perform single point analysis Peak width Peak threshold Use Line Tool to perform line scan analysis Analyze between User defined minimum and maximum thickness D mapping analysis

6 1 INTRODUCTION Axometrics Spectral Imaging Viewer Software is designed to perform imaging spectral measurement based on Axometrics Imaging Measurement system. 1.1 Instrument Files Directory Spectral Imaging Viewer Software folder should be put into same directory as all Axometrics instrument program files and support files: C:\AxoView\Current Version Do not change directory locations or filenames.. 2

7 2 SPECTRUM MEASUREMENT Spectral Imaging Viewer GUI is the main control program which is used to acquire spectrum images and provides frequency analysis to measure thin film or gap thickness. Each Spectral Imaging Measurement is a multiple image dataset containing data images at selected wavelength. The main screen of Spectral Imaging Viewer GUI is shown in the following figure. 2.1 Acquire Imaging Spectrum Follow the below steps to perform a spectral measurement TURN ON CONTROL UNIT Turn on control unit and open Spectral Imaging Viewer.exe (Do not start AxoStep Engine) WAVELENGTH SETTINGS Use Setting button to set the wavelength range and step. Currently, the wavelength range from 400 to 800nm at 5 or 10 nm steps has been tested and gives good results. 3

8 2.1.3 OPEN LIVE VIEW AND SET INITIAL EXPOSURE TIME Remove any sample. Use the Live View button to open live view window. Set the current wavelength to Minimum Wavelength. Then adjust the Exposure Time so that a bright field of view can be seen in live view window. The intensity should be in the range of 300 to 900 so that the following baseline calibration could be completed fast. Close the live view window. Users need adjust the condenser of input optical fiber to let suitable amount of light get into camera. Note: for 50X objective, due to the strong dark current and weak light at around 400 nm the working wavelength range is from 410 to 800 nm. Intensity in the range of 300 to 900 4

9 2.1.4 BASELINE Use the Baseline button to perform baseline calibration. It may take a few minutes. For larger objective, the baseline calibration takes longer time because exposure time is longer due to the less light. Dark and Reference data file will be saved in Spectral Imaging Viewer software folder: C:\AxoView\Current Version\ Spectral Imaging Viewer MEASURE Use the Measure button to perform a measurement. A pop-up window will prompt user to save the measurement data as *.axospec. 2.2 Analyze Spectrum CHOOSE SINGLE IMAGE Use the wavelength slide to show current image at selected wavelength. Wavelength slide 5

10 2.2.2 SINGLE POINT SPECTRUM Use the cursor tool to analyze the single point spectrum at any position. Cursor tool AVEARGED AREA SPECTRUM Use the draw square tool to analyze the averaged area spectrum at selected area. Square tool SHOW SPECTRUM IN CIE CHROMOTICITY COORDINATE In the spectrum graph short-cut menu, choose CIE Chromaticity Coordinate to show the spectrum in CIE chromaticity coordinate. 6

11 Show CIE Chromoticity Coordinate In CIE chromaticity coordinate window, users can choose different illuminant. 7

12 3 FREQUENCY ANALYSIS Frequency Analysis tool in Spectral Imaging Viewer is designed to perform thin film or gap thickness measurement based on Frequency analysis of measured spectrum data. Please note that the Frequency Analysis can only be used and give correct thickness results in some cases. For example, the thickness must be within some range (around 0.5um to 80um for air gap depending on scanned wavelength range and step). The transmittance on both interfaces of the gap or film must be comparable. The spectrum of the other layer in the same sample should not dominate the spectrum measurement. Therefore, not all the thicknesses of a multi-layer sample can be analyzed. Generally, thin film or gap need large scan wavelength range and thick film or gap need small scan wavelength step. 3.1 Set Refractive Index Use Refractive Index and Dispersion Button to set the refractive index. Using the Refractive Index setting window as shown below, Users can set the Cauchy Terms for dispersive materials. For non-dispersive material, set the Cauchy Terms B and C to zeros. Users can also import the index data in TAB-separated.txt file by pressing the Import Index Data for dispersive material. 8

13 Wavelength (nm) Refractive Index 3.2 Use Cursor Tool to perform single point analysis Use cursor to move to any position. The found frequency peaks and corresponded thickness will be shown in Frequency Analysis graph and Result Table. User need to adjust Peak Threshold (the red line) and peak width to find right peaks. User need to adjust X and Y range of Frequency Analysis graph to see the found peaks. Cursor tool Set refractive index Peak width control Found peak and corresponded thickness at cursor position Result table Peak threshold control 9

14 3.2.1 PEAK WIDTH Peak width specifies the number of consecutive data points to use in the quadratic least squares fit. width is coerced to a value greater than or equal to 3. The value should be no more than about 1/2 of the halfwidth of the peaks/valleys and can be much smaller (but > 2) for noise-free data. Large widths can reduce the apparent amplitude of peaks and shift the apparent location. For noisy data, this modification is unimportant since the noise obscures the actual peak. Ideally, width should be as small as possible but must be balanced against the possibility of false peak detection due to noise. When width is 5, 5 data points are fitted to find the peak. When width is 3, 3 data points are fitted to find the peak. When width is 7, this peak cannot be found And this peak can be found PEAK THRESHOLD Threshold instructs the program to ignore the peaks that are too small. The program ignores peaks if the fitted amplitude is less than threshold. Peak threshold is 9.19, two peak are found 10

15 Peak threshold is 15.13, only one peak is found 3.3 Use Line Tool to perform line scan analysis Use Draw Line tool to draw a scan line. Press Selected Line Frequency Transform button. A popup window will prompt users to confirm the peak finding parameter, peak threshold, peak width and peak location range. When there are more than one peak, setting the minimum and maximum peak locations makes only one desired peak analyzed. The corresponded thickness along the scan line will be shown in Thickness of Line Scan graph ANALYZE BETWEEN USER DEFINED MINIMUM AND MAXIMUM THICKNESS Setting the minimum and maximum peak locations makes only one desired peak analyzed. 11

16 Draw line tool Limit the peak location Thickness along the line Line transform button 3.4 2D mapping analysis In the spectrum graph short-cut menu, choose 2D frequency analyze to perform 2D thickness mapping analysis. 12

17 2D mapping Use Draw box tool to draw a box. Press 2D Analyze button. A popup window will prompt users to confirm the peak finding parameter, peak threshold, peak width and peak location range. When there are more than one peak, setting the minimum and maximum peak locations makes only one desired peak analyzed. The corresponded thickness 2D thickness map will be shown in Thickness Map graph. 13

18 Thickness at current cursor Progress bar Statistics 14