Hitachi 2015 Inspire Innovation Through Collaboration Hitachi High Technologies America, Inc.

A New Development to Eliminate Artifacts during TEM Sample Preparation in the FIB

Hitachi 2015

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A Common Problem

(Un)traditional FIB Preparation

• TEM preparation for lift-out has mostly become routine work on FIB-SEM systems recently, with standardized techniques that often are left to automation.

• Several papers addressing ion induced artifacts can be found when preparing lamellas at low kV relating to complex microstructures which often describe complex practices.

• Finalization of a lamella has mostly become: – non-routine – unreliable – Driven by user experience level (varied results, not repeatable)

Hitachi 2015

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A Common Problem

(Un)traditional FIB Preparation

End Point Detection Signal & Scanning System Solution

? Several factors that typically are key to reduce/eliminate ion beam induced artifacts include:

• Scan conditions • Ion species • Sample orientation • Ion beam incident angle • Reproducibility

Hitachi 2015

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Ion Milling Observation Signals

• Several users tend to view while thinning, more often than necessary. • An SEM column with in-column filtering for the separation of signals such as SE and BSE are essential for

identifying the target end point within a sample. • Viewing the lamella while ion milling can be challenging due to high SE signal generation.

BSE - Detector 2kV In-Lens SE Detector 2kV

Simultaneous Observation Cut & See Observation

End Point Detection

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A Common Problem

Ion Species

Damage Ion Species

Solution “The ion beam can be approximated as a

continuous heat source. At shorter times, there are large temporal variations in heating, and at times of less than 10–12 s, the atoms barely have time to interact with each other, and the temperature of the solid is not well defined.” Ref: MRS BULLETIN • VOLUME 32 • MAY 2007 • www/mrs.org/bulletin

Ar-Beam

SEM

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Ion Induced Damage Effects

Ion Species

Damage Gallium Ion

30kV Final Polishing

Gate Poly Si

Si sub

Gate Oxide

65nm NAND Flash

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Gallium Ion

Ion Induced Damage Effects

Ion Species

Damage

5kV Ga Final Polishing

Gate Poly Si

Si sub

Gate Oxide

65nm NAND Flash

5nm

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Real Time Fabrication with Low kV ArB Ion column

Ion Species FIB

Ar

Localized thermal/stress effects during Ga ion milling can induce

bending, which increases the likeliness of losing your lamella

Ar beam is broad and gentle.

Hitachi 2015

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Real Time Fabrication with Low kV ArB Ion column

Ion Species FIB

Ar Ar beam is broad and gentle.

Low energy Ar broad ion milling is less destructive and removes

amorphous material left behind by Ga milling

Hitachi 2015

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A Common Problem

Sample Orientation

Curtain Effect Sample Orientation Solution

? Sample orientation with respect to ion incidence angle can influence the planarity of the cross-section face.

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Ion Milling Result for 7-Axis Stage

Anti-Curtaining Function

SIM image of TEM lamella processed by S-axis±15°.

DRAM from Game Machine TEM image (Acc.: 200kV）

Hitachi 2015

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Ion Milling Result for 7-Axis Stage

Anti-Curtaining Function

SIM image of TEM lamella processed by S-axis±15°.

DRAM from Game Machine TEM image (Acc.: 200kV）

Hitachi 2015

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A Common Problem

Enhancing Reproducibility

Throughput Software + Hardware

Productivity, throughput and repeatability are comprised by synergy between:

• User • Application • Hardware*

Ref: http://en.wikipedia.org/wiki/File:Operating_system_placement.svg

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ACE Technology Solution

• A host of functions and components to reduce FIB related artifacts, called “ACE [Anti Curtaining Effect] Technology” have been developed that employ Ar/Xe ion beam milling and automated sample orientation control.

• The 7-axis stage, automated sample orientation control and combined triple beam FIB-SEM configuration, all of which essentially make up the ACE Technology suite.

• The processing of cutting edge devices in a FIB-SEM often requires specialized techniques and specific functions for producing ultra-thin lamella.

• The latest Hitachi FIB-SEM platform offers these innovations for reliability, repeatability and high quality lamella preparation for Cs Corrected (S)TEMs.

Summary

Thank You! Jamil J. Clarke Hitachi High Technologies Jamil.clarke@hitachi-hta.com

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