Transcript Surface Analysis Sales Meeting
The STATE of the art - XPS
Dr Chris Blomfield Dr Adam Roberts, Dr Simon Hutton Kratos Analytical Ltd www.kratos.com
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Distribution of XPS instruments
UK accounts for <15% of "state of the art" XPS 56% Industrial 44% Academic
UK France Germany
Based upon last ~ 50 instrument sales
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What are we missing out on?
• Sate of the art instruments offer: – Improved sensitivity • • improved detection limits reduced acquisition time – Smaller spot sizes • ~ 5 m spot size available – XPS imaging • 3 m spatial resolution
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3 decades of improvement
Ag 3d 5/2 FWHM Mono Mg 0.6eV
1.0eV
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Applications to
-CP
• • • • • • Patterning of polymer substrate (polyethylene PE) with poly(acrylic) acid PAA.
– PAA impermeable, wet and dry etch resist – – PAA films easily functionalised capped with PEG can be used for bio-applications cell growth Oxidised PE film is prepared PDMS stamp (optical mask) prepared with n-alkylamine PE “stamped” with amine to passivate PE Unpassivated regions react with PTBA Hydrolysis of this layer leads to PAA
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-CP process
alkyl amine Passivated layer PE-COOCOR PE-COOCOR i) PTBA ii) MeSO 3 H PE-COOCOR PDMS stamp Oxidised PE substrate Unpassivated region hyperbranched PAA film alkyl amine
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PAA on Au films
Au 4f photoelectron image attenuation of Au substrate gives contrast mechanism PAA layer alkyl amine Au substrate
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C 1s - 27
m analysis area
C 1s from PAA layer PAA
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Au 4f & C 1s image
< 3 m spatial resolution
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Fluorinated PAA on PE
Experiment repeated using PE substrate with PAA layer being fluorinated PE-COOCOR
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C 1s spectra
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Adhesive coverage on paper
• Inhomogeneous paper sample with uneven coverage of adhesive - lead to adhesive failure • Optically - sample was homogenous - white • XPS O1s image clearly identifies adhesive distribution
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O1s images variable FOV
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Chemical state images
• • C1s image allows investigation of chemistry – small spot analysis shows variation in C-H and C-O Energy resolution of SMA allows chemical imaging of different C 1s species
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C1s chemical state image
Indium in commercial Al-Zn-In sacrificial anode
• Improved detection limits<0.05% allow analysis of low concentrations of elements – Al-Zn-In anodes are used to protect marine steel structures from corrosion.
– study with XPS of the active In element – reveals surface segregation to a maximum of 4% over 1 year exposure
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In 3d quantification
In 3d 3/2 used for quantification Overlap with Ca 2s
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Corrosion tests
• • • Cut anode surface used to represent bulk – – XPS GDOES In In 0.02wt% 0.0185wt% As cast anode surface ~1wt% In Corrosion tests show an increase to 4wt% over 1 years simulated corrosion
In & Fe conc versus dissolution time
6 5 4 3 2 1 I u 0
m ) F 4
c t a d v s
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Summary
• In is surface segregated to Anode surface compared to the bulk -
inverse segregation
• In is believed to segregate to the
metal:oxide
interface a more active surface • Shows the activity of the anode is a surface phenomena - possible to investigate with improved detection limits
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Optical image contact pad
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Wide scan - low concentrations
O 1s C 1s Au 4f Co 2p Ni 2p 7.53% 37.0% 54.42% 0.78% 0.27%
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High resolution Co2p and Ni 2p
Co 2p 3/2 Co metal Co oxide Ni 2p 3/2
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Polymer reflector contamination
Cross section through a “dimple” PP contamination ca. 500 m
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Wide scan from 700
m area
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VB from 700
m area
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Valence band of PE & PP
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110
m spot size C 1s
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110
m spot size VB
VB in hole
PP character VB
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Bond pad contamination
Optical image of Al pads in-situ l Al 2p photoelectron image
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Bond pad contamination
• • Bad adhesion was observed in Al bond pads Optical images was used to identify area of know failure • XPS images and small spot show F contamination • Distribution of F indicates residue from plasma etching step in production
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Al 2p and F 1s images
F 1s image shows distribution of F on pads
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Small spot spectroscopy
55um spectra show Al/F on pad
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F 1s and al 2p images shwo distribution of F across bond pad
Photoelectron images
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Summary
• Modern XPS instruments are very powerful analytical tools • As well as improved automation, reliability and accuracy: – imaging, detection limits, resolution, probe.....
• How to get more instruments into UK????
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Acknowledgements
-CP Richard Crooks Texas A & M University In anode John Norris & Morgan Alexander. CPC, UMIST, UK
Polymer VB
Gary Korba 3M Central Research Labs Minneapolis
Paper sample
James Tse Avery Dennison Pasedena. USA