View source for Filmetrics F40-UV Microscope-Mounted

{{tool2
|super = Aidan Hopkins
|super2= Demis D. John
|picture=Filmetrics F40-UV - system pic 01.jpg
|type  = Inspection, Test and Characterization
|location = Bay #4
|description = Microscope-mounted optical reflectometry
|manufacturer = Filmetrics Inc.
|model = F40-UV
}}

==About==
The Filmetrics F40-UV is a microscope-mounted thin-film measurement system, allowing you to non-destructively measure thin-film thicknesses in small (patterned) areas on your sample.  The microscope is a standard Olympus BHJML metallurgical trinocular microscope. It is an optical reflectometer, acquiring reflection spectra between 400-900nm optical wavelengths (Vis to Near-IR) with a regular halogen microscope light source. The Filmetrics software then performs curve-fitting to determine the thickness and/or refractive index of the measured films.

==Capabilities==

*Measure optically transparent thin-films down to ~30nm thickness.
*Microscope Objectives: 10x, 20x, 50x, 100x, 150x
**Can measure thin-films in few-micron spot.
*Acquire Optical Reflection Spectra from 400-900nm
*Spectrometer/Detector is capable of detecting down to UV ~190nm, but light source does not support this wavelength.
*Reflectivity curve-fitting for thin-film thickness analysis, supporting many common materials (Si<sub>3</sub>N<sub>4</sub>, SiO<sub>2</sub> dielectrics, Si, GaAs, InP semiconductors, metals, photoresists etc.)
*Approx ≥20nm film transparent measurement up to tens of microns.

==Operating Procedures==

*[[Filmetrics F40-UV Quick Start|Quick Start Procedure]]

==Examples==

===Good Curve-Fitting===
Do not believe your thickness measurements unless the red/blue curves show a reasonably good match![[File:Filmetrics_F40-UV_-_Measurement_screenshot_on_metal_pad_01.PNG|alt=example spectrum curve fit|none|thumb|500x500px|Screenshot showing 10x microscope view and optical spectrum/curve fitting of the SiO2 film thickness on top of Platinum contact metal. This is considered a "reasonable" fit because the curves are very similar, but don't overlay perfectly, giving only reasonable confidence in the reported numbers.]]

[[File:Filmetrics F40-UV - spectrum curve fit 07.jpg|alt=example spectrum curve fit|none|thumb|300x300px|A good fit should show the Calculated (red) curve overlay on top of the Measured (blue) curve. This is a very good curve-fit and the reported thickness/index should be accurate.]]

===Checking whether a dry etch is complete===
The F40-UV is very useful for measuring whether a thin-film has been completely removed during a dry etch. This is similar to using [[Laser Etch Monitoring|laser monitoring]] during the etch, except that the microscope enables you to measure inside small patterned areas that a laser monitor spot may not fit inside.

In the following example, we are trying to etch away the SiO<sub>2</sub> from on top of a Platinum contact metal.  The 20x objective allows us to measure the SiO2 thickness on top of the Platinum as we continue to etch in 1 minute increments, measuring in between etches.

Finally, when the SiO2 has been fully removed, we see that we can't get a good fit between the measured (blue) and simulated (red) data.

Since the Platinum layer is thick enough to be opaque to visible light (>50nm), we just modelled this as SiO2 on top of Platinum, ignoring any other materials below the platinum.
{| class="wikitable"
|+
![[File:Filmetrics F40-UV - SiO Etch 4m+4m - Incomplete Etch.png|alt=Example Screenshot of incomplete SiO2 etch|none|thumb|400x400px|Incomplete Dry-Etch, showing some residual SiO2 left.  "Goodness of Fit" is close to 1.0 in the results pane, and the red+blue curves match closely so we believe the measurement.]]
![[File:Filmetrics F40-UV - 2018-11-08 - SiO Etch 4m+4m+1m - Fully Removed.png|alt=Example screenshot of fully removed SiO2 etch|none|thumb|400x400px|After re-etching, measurement shows bad fit (red and blue curves), and "Goodness of Fit" = 0 in the results pane.
The thickness value shown is not real, and this indicates that the SiO2 film has been fully removed since no parameter can give a good fit.  
]]
|}

==Other Info==
'''''Equip > Characterization > <u>[[Microscopes]]</u>''''' - ''see a list of all our microscopes''