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Lecture 11Chemical Engineering for Micro/Nano Fabrication

Oskar Süẞ (Suess)

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Blue Print Chemistry

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MeyerBaekeland

The History of Novolac

C.H. Meyer and L.H. Baekeland Discovered Novolac ca. 1900

OH

CH3

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Novolac Resin Production!!

Workers at Albert Co. in Wiesbaden, Germany

“zerkleinert das Harz von Hand” (ca. 1910)

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Oskar SüẞDer Diazo König

N2

O

SO3R

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Novolac/DNQ Photoresists

Develop

OH

CH3

Inhibited Novolac (I)

LogR

Novolac

UV

Coat

Expose

Substrate

II

I

I

I

I

I

I

I

I

I I

Substrate

II

I

I

I

I

I IP

PP

P

P

P

Substrate

I

I

I

II

I I

I

N2

O

SO3R SO3R

OOH

UV

OH

CH3

Photoproduct (P)

365-nm exposureAdd DNQ

I

P

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DNQ – Novolac Resists

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Wolff Rearrangement and Reaction of the ketene with water

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Polyphotolysis

I → S

I-I → S-I → S-S

I-I-I → S-I-I → S-S-I → S-S-S

This contributes to a threshold like

dissolution rate response to exposure

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I

No Swelling!!!!

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Quantifying Resist Performance

•Sensitivity• Intrinsic radiation sensitivity•Lithographic Sensitivity

•Contrast• Etch resistance

• Adhesion

• Shelf life

• Etc, etc, etc.

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Threshold like Response of ArF Resist

0.01

0.1

1

10

100

1000

10000

100000

1.0 10.0 100.0

DOSE(mJ/cm2)

dis

so

lutio

n r

ate

(A/s

ec)

total

surface

middle

bottom

E0

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Fundamental Measure of Resist Response

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