![Page 1: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/1.jpg)
FIB of the beaten path:TEM plan-view analysis using circuit-edit tools
Frans Voogt
EFUG 2008 meetingSeptember 29, 2008
![Page 2: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/2.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 2
Roadmap
• Phase-change memories
• TEM X-section preparation
• Development of plan-view preparation method
• Associated problems:
Charging damage
Beam damage
Ga haze
![Page 3: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/3.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 3
Chalcogenides: SbTe alloy (with dopants)Switching between two phases
Temp
Tm
Tr
Glass
Crystalline
Liquid
Programming history
![Page 4: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/4.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 4
Use as memory cells:
Amorphous = high R → “0”Crystalline = low R → “1”
Attractive candidate for non-volatile memories (RAM):+ Much faster than Flash+ Low operating voltage+ Better data retention+ Robust against radiation
But also:- Heat sensitive
![Page 5: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/5.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 5
NXP line cell concept©
Active part of the cell
• Ohmic heating of thin line• Integration in BEOL of
standard CMOS process
M1
M2
PCM cellElectrode
Transistor
![Page 6: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/6.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 6
Viewdirection
FIBetch
TEM sample preparation: FIB pluckering
![Page 7: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/7.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 7
From X-section to plan-view
“Double thinning”
- Time consuming- Risky: ~50% succes rate
due to stress in backend
90°
Thick cross-section
Thin plan-view
![Page 8: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/8.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 8
Backside circuit-edit FIB’s
CMOS090
Enhanced etch rates withspecial gases (XeF2)
![Page 9: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/9.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 9
Applied to PCM cells
Navigation with IR camera
Bondpad
Bondpad
Cell
Cell can be programmed !!
![Page 10: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/10.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 10
From FIB to TEM in four steps
![Page 11: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/11.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 11
Charging damagePCM lines either amorphous,with voids or blown-up altogether...
Charge accumulation due toimplanted Ga ions→ discharges through cell
![Page 12: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/12.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 12
Solution: Pt wires
Bond pads short-circuited → discharges through wire
![Page 13: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/13.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 13
Beam damageSample heating → diffusion → voids
Make samples as thin as possible
![Page 14: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/14.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 14
Single cells processed in CMOS13
“RESET” “SET”
![Page 15: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/15.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 15
Transfer to C065 process
CMOS13 single cell
C065
8×10 array
![Page 16: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/16.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 16
Different designs, same procedure
![Page 17: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/17.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 17
However: new problems arise...Image blurred by tiny particles...
C13 cell
Becomes more and more of aproblem with shrinking dimensions
C065 cell
![Page 18: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/18.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 18
Ga haze
Not only etching, but alsoimplantation
~1 nm per 1 keV→ ~30 to 50 nm
Ga+ ions
![Page 19: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/19.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 19
Solution: further sputtering with oxygen
With the aid of acalibrated ToF-SIMS tool
* Removal of Ga* Thinner sample→ Improved contrast
Low-keV O+ ions
![Page 20: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/20.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 20
Sample improvement
Shadowing
![Page 21: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/21.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 21
Outlook
• Further optimize oxygen sputtering
• Ph.D project RU Groningen
![Page 22: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/22.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 22
Also for other types of sample!
Substrate
BOX layer
SOI layer
![Page 23: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/23.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 23
First results SOI wafers
HAADF image: overview sample
HR BF image →(100) crystal lattice SOI film
Hole
![Page 24: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/24.jpg)
EFUG 2008, Frans Voogt, September 29, 2008
CONFIDENTIAL 24
Acknowledgements
Romain Delhougne (PCM samples)
Harry Roberts (FIB)David Donnet
Claud van Oers (ToF-SIMS)
![Page 25: FIB of the beaten path - imecefug.imec.be/EFUG2008_03_Voogt.pdf · FIB of the beaten path: TEM plan-view analysis using circuit-edit tools Frans Voogt EFUG 2008 meeting September](https://reader034.vdocument.in/reader034/viewer/2022042122/5e9d3ed33445ef5f2b7630bb/html5/thumbnails/25.jpg)