2014 International Symposium on Extreme Ultraviolet Lithography

Development of EUV patterned mask inspection technologies for the 16 nm - 11 nm half pitch generation Ryoichi Hirano, Susumu Iida, Tsuyoshi Amano and Hidehiro Watanabe EUVL Infrastructure Development Center, Inc.

Masahiro Hatakeyama, Takeshi Murakami and Kenji Terao EBARA CORPORATION

Detecting the defects of smaller than 15 nm in size is required for hp 11 nm EUV mask as described in ITRS 2013 Edition. In order to achieve the inspection sensitivity and the extendibility to sub-16-nm node defect detection, Projection Electron Microscope (PEM) technique with high-resolution and high-throughput Electron Optics (EO) are developed.

Introduction

Concept of the Patterned mask Inspection (PI) tool development.

This work is supported by New Energy and Industrial Technology Development Organization (NEDO) and Ministry of Economy, Trade and Industry (METI) .

Defect size &

configuration 13 nm extrusion 12nm intrusion

Defect SEM image

in hp 64 nm

Image difference (binary)

and

captured PEM image

(superimposed)

16 nm sized intrusion defect, which is our target for hp 16 nm defect detection requirement, was identified without false defects.

Defect size

&

configuration

16 nm Intrusion

SEM Image

Defect

detection

Result

19 hrs. Inspection throughput for 100 mm sq. of full mask area inspection was actually confirmed by measuring the mask scanning time.

Phase1

2011.4～2014.3

Phase2

2014.4～2016.3

Target node hp 16 nm hp 11 nm

Capability 16 nm isolated

16 nm edge

11 nm isolated

11 nm edge

Scan time 19 hrs

/100mm sq.

<8 hrs

/100mm sq.

Processing

rate 600 MPPS >1.5 GPPS

Inspection

mode Die-Die Die-Die

Schematic view of the pattern inspection system Model EBEYE-V30.

PEM

optics

Vacuum chamber

with

load-lock Chamber

Environment

Control Chamber

System

Controller

Dual-pod EUV mask

loader

"Model EBEYE" is an EBARA's model code.

Ru(2.5 nm)

TaBN(52 nm) TaBO(14 nm)

Multi-layer(40 pairs)

Acknowledgements Toshiba: Masato Naka, Ryoji Yoshikawa, Takashi Hirano and Masamitsu Itoh

EBARA: Tsutomu Karimata, Kenji Watanabe and Shoji Yoshikawa

NANOTECH CO., LTD : Tetsuya Narishima, Tsuyoshi Tomita and Hideyuki Nakamori

Defect inspection requirement for hp 11 nm.

PEM optics

EUV mask

High precision X-Y stage

High speed

Image processing

High speed

Image sensor

Bright and stable

electron source

High speed image sensor, high speed image processing circuit and bright/stable electron source are necessary for hp 11 nm defect inspection.

To improve the inspection throughput for hp 11 nm node defect detection, >1.5 GPPS data processing rate realizes less than 8 hours of inspection time.

13

ΔCD<10%

Luminescent LAIPHTM Defect Printability Simulator

Illumination conditions: NA: 0.45

Illumination type: Dipole Sigma(Inner): 0.2-

Sigma(Outer): -0.4/0.9

From the simulation result of defect pattern size vs. hp 11 nm L/S printed pattern size on wafer, more than 13 nm extrusion defect or more than 20 nm intrusion cause more than 10% Critical Dimension (CD) error for hp 11 nm EUV lithography.

The signal intensity increases at the position of the defect, and if the signal intensity value exceeds a threshold level set for the defect detection of the targeted defect size, the defect is then identified.

Defect detection extendibility for hp 11nm node.

Applying the die-to-die defect inspection to the captured image, the targeted defects are clearly identified.

Summary

We are developing a novel projection electron microscope (PEM) inspection system for smaller than 16 nm sized

defect detection.

PEM system design and performance evaluation are executed and have achieved 16 nm inspection sensitivity.

Target specification of our developing inspection tool defect size: >11 nm, inspection time:<8 hours.

Applying the I2U correction to the captured image, the targeted defects are clearly identified without false defects.

Defect detection sensitivity of 12 nm sized intrusion defect in hp 64 nm on the mask was clearly identified.

EUV mask

Illumination

unit

Imaging unit

Projection

Lens

Beam Separator

Cathode Lens

Photoelectron

source

TDI

(Time Delay Integration)

sensor

*PEM: Projection Electron Microscope

Schematic view of Projection Electron

Microscope.

PEM probes sample mask with areal illumination. As a result, PEM improves the inspection throughput.

Specification of the Developing PI.

PEM image in hp 64 nm Defect detection signal

intensity map

Signal enhancement & subtraction

Defect detection signal intensity map analysis

Defect detection sensitivity evaluation results

Standard deviation of S/N map is improved by I2U correction.

Defect detection capability enhancement -I2U correction-

𝑺 𝑵 =𝑺𝒊𝒈𝒏𝒂𝒍 𝒊𝒏𝒕𝒆𝒏𝒔𝒊𝒕𝒚

𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏

We determine the specification of developing PI tool to fit the requirements of hp 16 nm an d hp 11 nm HVM.

Inspection area: 100 mm sq.

Insp

ec

tio

n t

ime

ho

urs

19H/mask

8H/mask

1.5 GPPS Printed space width

Defect detection

with false defects

Image difference (binary) and Inspection Image (superimposed)

Defect detection

w/o false defect 32 nm extrusion defect SEM

image in hp 64 nm

45 nm intrusion defect

SEM image in hp 64 nm

Intra-field Image Intensity Unevenness is adjusted by I2U correction. The signal intensity distribution in a processing window is adjusted for the defect detection w/o false defect.