az barli ii data package - microchemicals · data package. az, the az logo, barli ... registered...

AZ BARLi IISolvent Compatible Bottom Antireflective

Coatingfor i-Line Process

Data Package

AZ, the AZ logo, BARLi, Aquatar, nLOF, Kwik Strip, Klebosol, and Spinfil are registered trademarks and AX, DX, HERB, HiR, MiR, NCD, PLP, Signiflow, SWG, and TARP are trademarks of AZ Electronic Materials.

AZ BARLi II Coating Material

Features, Process, and Performance

AZ’s bottom antireflective coating material, AZ BARLi II coating, is tailor-made to yield near-optimum values for refractive indices (n and k) for i-line lithography, which ensures minimum reflectivity and maximum swing reduction for photoresist layers.

AZ BARLi II coating material is formulated in photoresist-compatible solvents to simplify edge bead removal process and to be both environmentally and user friendly.

Composed of highly absorptive polymer-bound dyes, this material provides excellent coating uniformity and step coverage. Other features include high etch selectivity and good thermal stability.


AZ BARLi II Coating Material

Features/Benefits

▶ Highly absorptive polymer-bound dye used as the bottom antireflective coating for i-line photoresists

▶ Near-optimal optical constants (n/k=1.63/0.31) for maximum swing reduction at the optimal film thicknesses (910Å and 1960 Å)

▶ Formulated with photoresist-compatible solvents to simplify EBR process and to be end-user friendly

▶ Excellent coating uniformity and step coverage profile▶ High etch selectivity, comparable to AZ BARLi coating material▶ High thermal stability up to 230°C▶ No intermixing with photoresist layer after soft baking▶ Two thickness grades, AZ BARLi II 90 and 200, provide the optimal

film thickness for the first and the second swing minimum respectively


Optical Constants of AZ BARLi and AZ BARLi II Coatings

Near-optimal values of n and k at 365 nm, both AZ BARLi and AZ BARLi II coatings are highly absorptive materials for i-line

process

Coating Wavelength (nm)

n from spectr. ellipsometry

k from spectr. ellipsometry

BARLi

365

1.65

0.33

BARLi II

365

1.63

0.31

BARLi film baked at 150 °C, BARLi II film baked at 200°C


Simulated Swing Reduction of Photoresist by AZ BARLi II Coating

Resist (n=1.704-0.024i) on AZ BARLi II (n=1.63-0.31i) on Si (n=6.55-2.07i), 365nm

0

0.2

0.4

0.6

0.8

1

0 0.1 0.2 0.3 0.4BARLi II Thickness (µm)

Nor

mal

ized

Sw

ing

Am

plitu

de

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

Ref

lect

ivity

SR

minimum reflectivity: 0.013%minimum swing amplitude: 1.80%


AZ® BARLi II Reflectivity Simulation

0.00

0.02

0.04

0.06

0.08

0.10

0.12

50 100 150 200 250 300 350BARLi II thickness (nm)

BA

RLi

II R

efle

ctiiv

ty

-g line

-h line

-i line

Wavelength 1st minima FT Reflectivity 2nd minima FT Reflectivity( λ) (nm) (%) (nm) (%)

-i line 94 0.0330 200 0.0002-h line 98 0.0430 212 0.0031-g line 98 0.0570 216 0.0111


Swing Curves of AZ 7908 Photoresist on AZ BARLi II Coatings

AZ BARLi II coatings reduced swing amplitude by 80% at 900Å film thickness and 94% at 1960Å

p

40

50

60

70

80

90

100

110

120

130

0.75 0.8 0.85 0.9 0.95 1 1.05 1.1Film Thickness [µm]

Ener

gy (m

j/cm

²)

AZ BARLi II at 900Å (blue) and 1960Å (red)SB 90°C/60sec, PEB 110°C/60sec, AZ 300MIF Developer, 70sec puddle @23°C


Thermal Stability of AZ BARLi II Coating

Refractive index k changed < ±2% at softbake temperature from 160°C to 230°C, providing wide process latitude.

Refractive Index K vs. Softbake Temperature

0.28

0.3

0.32

0.34

0.36

140 160 180 200 220 240SB Temperature (°C)

K

0.09µm0.20µm


Spin Curves of AZ BARLi II Coatings

Two thickness grades of AZ BARLi II coatings provide 1st and 2nd optimal FT respectively at standard operating conditions (spin @ 3000rpm,SB @ 200°C/60sec.)

Spin Curve at 200°C Softbake

0

500

1000

1500

2000

2500

3000

3500

4000

0.5 1 1.5 2 2.5 3 3.5 4 4.5Spin Speed (rpm x 1000)

Film

Thi

ckne

ss (Å

)

0.09µm0.20µm



Optical density of AZ BARLi II film varied < ±1.0 % from 50°C to 210°C, indicating high thermal stability.

Absorbance loss vs. softbaking temperature

-10

-5

0

5

10

50 100 150 200 250

Softbake temperature (°C)

Abs

. los

s (%

)

Abs.Abs/µm



No intermixing with photoresist solvents observed after soft baking at 170°C or higher

AZ BARLi II Film Loss vs. Soft Baking Temperature

-10

0

10

20

30

40

50

110 130 150 170 190 210 230

Bake Temperature (°C)

Film

Los

s (%

)

Sampe1Sample2

AZ BARLi II films soft baked at 200°C for 60 sec., and then soaked in EL for 60 sec.


Etch Test of AZ BARLi and AZ BARLi II Coatings

Both AZ BARLi and BARLi II coatings are highly etchable

Etch conditions: Samco RIE-10N, CHF3/O2 in 40/10 sccm, 60w, 60 seconds.

Etch Rate vs. Softbake Temperature

0

200

400

600

800

1000

BARLi II BARLiSoftbake Temperature (°C)

Etc

h R

ate

(Å/m

in)

170°C200°C230°C

AZ 7900


Etch Selectivity of AZ BARLi and AZ BARLi II Coatings

Both AZ BARLi and AZ BARLi II coatings showed etch selectivity of higher than 1.4 vs. Novolak-based photoresist

Etch conditions: Samco RIE-10N, CHF3/O2 in 40/10 sccm, 60w, 60 seconds.

AZ 7900

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

BARLi II BARLi

Softbake Temperature (°C)

Etc

h se

lect

ivity

170°C200°C230°C


Sublimation Test of AZ BARLi and BARLi II Coatings

AZ BARLi II coating showed high thermal stability and no sublimation of absorptive materials at up to 240°C

Sublimation test: AZ BARLi II coated @ 0.3 µm onto ten 4” Si-wafers and each baked for 120sec, quartz wafer measured for absorbance after 10 Si-wafers baked.

Wafer

Hot Plate

Quartz plate

UV absorbance of quartz plate

0.000

0.100

0.200

0.300

0.400

0.500

0.600

AZ BARLi II AZ BARLi

UV A

bsor

banc

e

200 °C

220 °C

240 °C


Topography Profiles of AZ BARLi II Coating

AZ BARLi II coating showed good conformity properties

AZ BARLi II material coated onto SiO2 wafers with contact holes at ~1.7 µm deep and 0.4 µm open.


SEM Micrographs of AZ 7908 Resist on AZ BARLi II and AZ BARLi

Resolution better than 0.32µm, showed AZ BARLi II and AZ BARLi coatings are comparable

AZ BARLi II &AZ BARLi FT at 0.19µm, SB 200°C/60sec., AZ 7908 FT at 0.97µm, SB 90°C/60sec., PEB 110°C/60sec., Developer AZ 300MIF 23°C/70sec., Exposure Nikon 0.54NA i-line.

AZ BARLi II: 0.30µm 0.32µm 0.34µm 0.36µm 0.38µm

AZ BARLi: 0.30µm 0.32µm 0.34µm 0.36µm 0.38µm


SEM Micrographs of AZ 7908 Resist on AZ BARLi II and BARLi

DOF 1.2µm (at 0.34µm), comparable performance for both AZ BARLi II and AZ BARLi coatings.

AZ BARLi II & AZ BARLi FT at 0.19µm, SB 200°C/60sec., AZ 7908 FT at 0.97µm, SB 90°C/60sec., PEB 110°C/60sec., Developer AZ 300MIF 23°C/70sec., Exposure Nikon 0.54NA i-line.

AZ BARLi IIDOF: -0.8µm -0.6µm -0.4µm -0.2µm 0.0µm +0.2µm +0.4µm

AZ BARLiDOF: -0.8µm -0.6µm -0.4µm -0.2µm 0.0µm +0.2µm +0.4µm


Recommended Standard Process

▶ Substrate Pre-TreatmentHMDS not recommended.

▶ Spin ProcessTarget thickness: 910Å for AZ BARLi II 90

1960Å for AZ BARLi II 200Spin and EBR process similar to photoresist process.Apply static or dynamic dispense at 500-1000rpm.Final spin speed approx. 3000rpm, actual setting depends on equipment, set spin speed to meet target thickness as above.

▶ EBR ProcessAZ EBR70/30 recommended for best result.Also compatible to EL, PGME, or other solvents.


Recommended Standard Process (continued)

▶ SoftbakeRecommended setting: 200°C/60seconds on contact hotplate.Depending on equipment, temperature may be set between 180°C to 220°C and proximity bake may be applied.

▶ StripAZ 300T and 400T strippers are recommended.

▶ Solvent SafetyBARLi II coatings are formulated with EL/PGME.

▶ StorageStoring in refrigeration is recommended.

▶ Shelf LifeShelf life in room temperature is 12 months.


AZ BARLi II Thickness Measurement

The Cauchy coefficients for AZ BARLi II coating are:

A = 1.6097B = 0.0083014C = 0.006187 ( measured by J. A. Woollam V.A.S.E.® Spectroscopic Ellipsometer)

They fit the following equation:

n = A + B/ Σ2 + C/ Σ4

where B in µm2, C in µm4.If using nm, then multiply B by 106, C by 1012;If using Å, then multiply B by 108, C by 1016.


Summary

▶ AZ BARLi II coating material has near-optimum values of refractive indices for i-line lithography.

▶ AZ BARLi II coating material is formulated in photoresist compatible solvents.

▶ AZ BARLi II coating material performs comparable to AZ BARLi coating.

▶ AZ BARLi II coating material is composed of polymer-bound dyes, no sublimation of monomeric dyes and other materials during soft baking.

az barli ii data package - microchemicals · data package. az, the az logo, barli ... registered...

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