Saturday 10 September 2016

SPECTROSCOPIC REFLECTANCER AND REFRACTIVE INDEX MEASUREMENT .


Spectroscopic reflectance is a powerful method of thickness and optical constants measurement.  The Thickness of, practically, any translucent material in 1nm -1mm thickness range can be measured. Optical constants can be measured for material thicknesses 20nm -20μm.  However, there is one limitation – in order to measure optical constants, material need to be absorbing (k>0). If material has k=0, thickness and refractive index cannot be measured independently – they are correlated. The k>0 requirement is easily understood intuitively – absorption constraints the thickness and thus de-correlates thickness and refractive index measurement.

One approach is to select wavelength range where k>0 (typically in UV). For example, SiN or TiO2 have k=0 in the visible range  but nice absorption edge in the UV, so using UVVis spectrum one can reliably determine  thickness and n & k of these materials.  Some materials, like SiO2, are dielectric in a very wide spectral range but, in many cases, they have some surface roughness or non-uniformity that causes light scattering. Small light scattering has the effect similar to absorption and allows to determine thickness and R.I. independently especially in thicker films (several µm).             

There is one special case when R.I. of dielectric film can be determined very accurately along with the thickness without a need for absorption. This happens when there are 2 layers (or layer on substrate) that have similar R.I., one R.I. (e.g. substrate) is known and film is relatively thick (several µm). For example, 16um polymer film on glass (glass R.I. 1.5, polymer R.I. ~ 1.6). 

Two figures below (Fig.1 and Fig. 2) show the effect of the R.I. on reflectance spectrum. Optical contrast (difference between R.I. of the materials) affects strongly the amplitude of interference fringes (peaks of constructive and deconstructive interference).  The better is optical contrast – the stronger is amplitude. As a result, R.I. index can be determined independently – thickness has no effect on the amplitude of interference peaks. This allows us to determine R.I. and improve accuracy of thickness measurement at the same time. 

Note. In this example, polymer was deposited on a thin glass (~ 1.3mm) and backside reflectance of the glass was included in the model. This is typical to LCD applications.  Polymer dispersion (R.I.) was represented using Cauchy approximation (see Fig. 3)  
                                      

Fig. 1. Polymer on glass. Reflectance spectrum 700-1000nm. Fit between measured (RED) and model (Blue) data for polymer R.I.=1.582 at 800nm. Small amplitude of the model data shows that R.I. of the polymer is higher .


Fig. 2.  Same as Fig.1 but polymer R.I. is adjusted to 1.667 at 800nm. . Fit between measured (RED) and model (Blue) data is good now. Both thickness and R.I. can be determined independently.  

                                      
  
Fig. 3   R.I. of the polymer film (700-1000nm) determined from the measurement.R.I. dispersion is represented using Cauchy approximation 

SPECTROSCOPIC REFLECTANCER AND REFRACTIVE INDEX MEASUREMENT .


Spectroscopic reflectance is a powerful method of thickness and optical constants measurement.  The Thickness of, practically, any translucent material in 1nm -1mm thickness range can be measured. Optical constants can be measured for material thicknesses 20nm -20μm.  However, there is one limitation – in order to measure optical constants, material need to be absorbing (k>0). If material has k=0, thickness and refractive index cannot be measured independently – they are correlated. The k>0 requirement is easily understood intuitively – absorption constraints the thickness and thus de-correlates thickness and refractive index measurement.

One approach is to select wavelength range where k>0 (typically in UV). For example, SiN or TiO2 have k=0 in the visible range  but nice absorption edge in the UV, so using UVVis spectrum one can reliably determine  thickness and n & k of these materials.  Some materials, like SiO2, are dielectric in a very wide spectral range but, in many cases, they have some surface roughness or non-uniformity that causes light scattering. Small light scattering has the effect similar to absorption and allows to determine thickness and R.I. independently especially in thicker films (several µm).             

There is one special case when R.I. of dielectric film can be determined very accurately along with the thickness without a need for absorption. This happens when there are 2 layers (or layer on substrate) that have similar R.I., one R.I. (e.g. substrate) is known and film is relatively thick (several µm). For example, 16um polymer film on glass (glass R.I. 1.5, polymer R.I. ~ 1.6). 

Two figures below (Fig.1 and Fig. 2) show the effect of the R.I. on reflectance spectrum. Optical contrast (difference between R.I. of the materials) affects strongly the amplitude of interference fringes (peaks of constructive and deconstructive interference).  The better is optical contrast – the stronger is amplitude. As a result, R.I. index can be determined independently – thickness has no effect on the amplitude of interference peaks. This allows us to determine R.I. and improve accuracy of thickness measurement at the same time. 

Note. In this example, polymer was deposited on a thin glass (~ 1.3mm) and backside reflectance of the glass was included in the model. This is typical to LCD applications.  Polymer dispersion (R.I.) was represented using Cauchy approximation (see Fig. 3)  
                                      

Fig. 1. Polymer on glass. Reflectance spectrum 700-1000nm. Fit between measured (RED) and model (Blue) data for polymer R.I.=1.582 at 800nm. Small amplitude of the model data shows that R.I. of the polymer is higher .


Fig. 2.  Same as Fig.1 but polymer R.I. is adjusted to 1.667 at 800nm. . Fit between measured (RED) and model (Blue) data is good now. Both thickness and R.I. can be determined independently.  

                                      
  
Fig. 3   R.I. of the polymer film (700-1000nm) determined from the measurement.R.I. dispersion is represented using Cauchy approximation 

Monday 7 March 2016

Thickness Measurement

                                                        
                                  Thickness Measurement


Measurement of coating thickness is  an important method for standard testing of many  products.  Measurement of coating thickness isn't that straightforward and many advanced tools and instrumentality to research the thickness.

Optical thin-film measurements are indirect - they, actually, include two steps:

1.      Measurement of reflectivity/transmittance spectrum of the sample
This step includes collecting the signal from spectrometer (raw data) and normalizing it using calibration data.
2.      Analysis of measured data using optical model of the sample (filmstack). Software compares measured and simulated data and infers the filmstack parameters (calculated thickness and/or optical properties) from the best fit (curve fitting).
 

 MProbe thickness measurement system is a popular coating thickness gauge. This is a perfect device to measure thickness and optical constants  fast and accurately.

Now you need to be thinking is it extremely helpful to see the thickness measurement? The solution is yes! measurement of the thickness is vital as a result of if the thickness is a smaller amount or we are able to say inadequate, then it'd not be able to cowl the merchandise or substance as per needs and if it's over what's needed, then it'd get dry or get cracks that once more hamper the standard and look of the merchandise. So, it's necessary to use accurate thickness measurement instrument and tools that may analyze the precise quantity of thickness in a very short span of your time.

Now you need to be thinking that instruments are sensible to use and from wherever will you purchase them? These devices are ideal for measure thickness as they will measure thickness starting from five to twelve layers. Moreover, they're the Windows based mostly systems and folks will simply operate them with none problems. Further, they're convenient and simple to put in.

There are varied makers and sellers available those are providing these gauges and instruments through that you'll analyze the precise coating thickness. Finding the simplest and authentic company is troublesome however not possible. You'll conduct an internet analysis to seek out the credibility of the manufacturer also because the quality and practicality of those tools and instrumentality. The foremost essential things are that you simply got to check embrace the expertise and name of the corporate also because the costs and quality of the product. You'll conjointly use any in style computer program to seek out the simplest firms.


If you are looking for most excellent thickness measurement services, you can get in touch with Semiconsoft.com where we take pride in building reasonably priced, reliable and user-friendly instruments for measurement of thickness. SemiconSoft offers the premier supply of thin-film thickness measurement instruments as well as thin film measurement systems, optical spectroscopy devices and data analysis software package. MProbe (Thin-film system) is the brand of Semiconsoft,Inc. We have a team of experts who will help you select a system configuration for specific application.

Monday 29 February 2016

Polymer Thickness










There exist many forms of optical solutions that illustrate the thickness of a thin film and thick coating thickness. 

MProbe system is successfully used for measurement of a wide variety of polymer films. Depending on application requirements different configuration can be selected:
1. MProbe Vis system (wavelength 400-1000nm) is used for measurement of the polymer films from 15nm to 20µm.  For films <500nm, typically, only thickness can be measured. For thicker films both thickness and refractive index can be measured.
2. MProbe UVVis (wavelength 200-1000nm) can be used when information about polymer properties is important. Most of polymers have absorptions edge in the UV, so n,k can be measured along with the thickness. Also very thin polymer films (monolayer) can be measured.
3. MProbeVisHR or NIR is used for measurement of thick polymer films >20μm  or  films than are not clear (colored) or have scattering.
 

They are collectively helpful in learning the surface and interface behavior of a thin-film. A film's optical properties like ratio that's denoted by letter N and extinction constant i.e. K will even be explained by this result. The concentrations of an alloy and its consistency are determined with the help of solutions provided. For people who are looking for film gauge thickness measure equipments and need to measure thin-film, they'll choose these devices for this purpose. Such devices allow to record film thickness in up to 5 layers thick filmstack. The tools are  easy to use  as a  Windows based package. 
Coating thickness or film thickness analysis is a vital method in endeavor the standard testing method of a product or substrate material. It plays a significant importance in analyzing the standard of the merchandise as a result of coating thickness affects the finished quality of a product. Activity coating thickness isn't that simple and thence the standard analysts use many advanced tools and instrumentality to investigate the thickness. The foremost well-liked and wide used device is coating thickness gauge. This can be the perfect device that measures the precise thickness furthermore as helps in maintaining the correct quality.

There are various makers and sellers who are providing these gauges and instruments through that you'll be able to analyze the precise coating thickness. Finding the most effective and authentic company is troublesome however not possible.
If you are  searching for the best instruments to measure the thickness of polymer or different instruments that are ideal for thickness measurement, then realize the most effective company SemiconSoft Inc.

SemiconSoft, Inc is that the premier supply of thin-film thickness measurement instruments.MProbe(Thin-film system) is a brand of SemiconSoft,Inc . We offer thin film measurement systems, optical chemical analysis tools and information analysis software system. Our techniques are Non-destructive techniques so can be engineered to cope with coatings, linings. in order to measure 0.1 mm and less we use standard timing techniques so that we can maintain Good accuracy.Our devices are easy-to-use, low-cost, and backed with unrivaled support. You can get more details about instruments and our services on main website http://www.semiconsoft.com  


www.Semiconsoft.com
   Email-info@semiconsoft.com
                                                                              Phone No-+1 424-273-1647