pmma data sheet from microchem

5/21/2018 PMMA Data Sheet From Microchem

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PMMA (polymethyl methacrylate) is a versatile polymeric material that is well su

for many imaging and non-imaging microelectronic applications. PMMA is m

commonly used as a high resolution positive resist for direct write e-beam as wel

x-ray and deep UV microlithographic processes. PMMA is also used as a protec

coating for wafer thinning, as a bonding adhesive and as a sacrificial layer.

Standard PMMA products cover a wide range of film thicknesses and are formula

with 495,000 & 950,000 molecular weight (MW) resins in either chlorobenzene

the safer solvent anisole. Custom MW products ranging from 50,000 - 2.2 million

available upon request. In addition, we offer copolymer (MMA (8.5) MAA) produ

formulated in the safer solvent ethyl lactate. All MCC PMMA and copolymer res

are available in package sizes from 500ml to 20 liters.

NANOPMMA and Copolymer

MCCPRODUCT ATTRIBUTES

Submicron linewidth control

Sub 0.1m imaging

E-beam, X-ray & deep UV imaging

Broad range of molecular weights & dilutions

Excellent adhesion to most substrates

Compatible with multi-layer processes

APPLICATIONS

Multi-layer T-gate processing

Direct write e-beam lithography

Protective coatings for wafer thinning

Adhesive for X-ray LIGA processing

Sacrificial layers

100nm gate profile imaged in 495K PMMA with 8.5 MAA Copolymer on top.

T-gate resulting from PMMA/Copolymer bilayer resist stack.

courtesy M/A Com

courtesy M/A Com


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PROCESSING GUIDELINES

Substrate Preparation

Thesubstrate should be clean and dry. Solvent,O2 plasma, and O3

cleans are commonly used and recommended.

Coat

MicroChemPMMAresists produce low defect coatings overa broad

range of filmthicknesses. Thefilmthickness vs.spin-speed curves

displayed in Fig. 1 through 8 provide the information required to

select the appropriate PMMA dilution and spin speed needed to

achieve the desired film thickness.

The recommended coating conditions are:

(1) Dispense: STATIC 5 - 8ml for a 150mm wafer

(2) Spread: DYNAMIC 500 rpm for 5 sec OR

STATIC 0 rpm for 10 sec

(3) Spin: Ramp to final spin speed at a high acceleration

rate and hold for a total of 45 seconds.

Pre Bake

PMMA

Hot plate: 180o

C for 60 - 90 sec ORConvection Oven: 170oC for 30 min

Copolymer

Hot plate: 150oC for 60 - 90 sec OR

Convection Oven: 140oC for 30 min

*Vacuum oven bake can also be used

Spin Coat

Bottom Layer

PMMA Resist

Prebake

PMMA

Prebake

Copolymer

Expose and

Develop

Resist Stack

Spin Coat

Top Layer

Copolymer Resist

Remove Resist

Edge Bead

Gate Etch and

Deposition

Strip/Remove

Resist Stack

Typical process flow for bi-layer T-gate proces

1. 2.

4.3.

.6.5

8.7.


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Expose

PMMA can be exposed with variousparts of the electromagnetic

spectrum.

e- beam:Do se - 50 - 500 C /cm 2 depending on radiation

source/equipment & developer used.

Energy 20-50kV; higher kV for higher resolution, e.g. 50kV for

0.1mm images.

DUV(deep UV):Low sensitivity, requiring doses >500mJ/cm2

at 248nm.

X-ray: Sensitivity of PMMA is low, ~1-2 J/cm2at 8.3. The

sensitivity increases at longer x-ray wavelengths. Features of


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10000

9000

8000

7000

6000

5000

4000

3000

2000

1000

0

500 1000 1500 2000 2500 3000 3500 4000 4500

FilmT

hickness()

Spin Speed (rpm)

C4

C2

C6

495PMMA C Resists

Solids: 2% - 6% in Chlorobenzene

Figure 1

23000

21000

19000

17000

15000

13000

11000

90007000

5000

500 1000 1500 2000 2500 3000 3500 4000 4500

FilmT

hickness()

Spin Speed (rpm)

C8

C9

495PMMA C Resists


Figure 2

1000

2000

3000

4000

5000

6000

7000

0

500 1000 1500 2000 2500 3000 3500 4000

FilmT

hickness()

Spin Speed (rpm)

A6

A4

A2

495PMMA A Resists

Solids: 2% - 6% in Anisole

Figure 3

5000

10000

15000

20000

25000

0

500 1000 1500 2000 2500 3000 3500 4000

FilmT

hickness()

Spin Speed (rpm)

A11

A8

495PMMA A Resists


Figure 4

0

2000

4000

6000

8000

10000

12000

FilmT

hickness,

()

500 1000 1500 2000 2500 3000 3500

Spin Speed (rpm)

EL 11

EL 9

EL 6

4000 4500

Copolymer Resists

Solids: 6% - 11% in Ethyl Lactate

SPIN SPEED CURVES FOR PMMA AND COPOLYMER RESISTS

Thespin speed versusfilm thickness curvesdisplayed in figures1-11 provideapproximate information required to select the appropriate PMM

copolymer resist and spin conditions needed to obtain the desired filmthickness.Actualresults will varyand are equipment, environment,proces

application specific. Additional resist dilutions to obtain other film thicknesses are available upon request.

Figure 9


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55000

50000

45000

40000

35000

30000

25000

20000

15000

10000

500 1000 1500 2000 2500 3000 3500 4000 4500

FilmT

hickness()

Spin Speed (rpm)

C9

C10

950PMMA C Resists


Figure 5

0

5000

10000

15000

20000

25000

500 1000 1500 2000 2500 3000 3500 4000 4500

Spin Speed (rpm)

C7

C4

C2

FilmT

hickness()

950PMMA C Resists


Figure 6

4000

6000

8000

10000

12000

0

2000

500 1000 1500 2000 2500 3000 3500 4000

FilmT

hickness()

Spin Speed (rpm)

A7

A4

A2

950PMMA A Resists


Figure 8

55000

50000

45000

40000

35000

30000

25000

20000

15000

10000

500 1000 1500 2000 2500 3000 3500 4000 4

FilmT

hickness()

Spin Speed (rpm)

A9

A11

950PMMA A Resists


Figure 7

1.45

1.5

1.55

1.6

1.65

1.7

RefractiveIndex

0 300 500 700 900

Wavelength (nm)

Cauchy Coeffiecients

A B C

495 PMMA 1.491 3.427 e-03 1.819 e-04950 PMMA 1.488 2.898 e-03 1.579 e-04

1.45

1.5

1.55

1.6

1.65

1.7

RefractiveIndex

0 300 500 700 900

Wavelength (nm)

Cauchy Coeffiecients

A B C

8.5 mEL 1.478 7.204 e-04 -3.478 e-0

Optical Properties

Copolymer Resists

Figure 10 Figure 11

Optical Properties

495 and 950 PMMA Resists


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Bi-Layer Process

2. Coat and bake copolymer

4. Expose resist stack, center scan dose,then side scan dose

1. Coat and bake high MW PMMA

PMMA

GaAs

Copolymer

PMMA

GaAs

3. Coat and bake low MW PMMA

CopolymerPMMA

PMMA

CopolymerPMMA

PMMA

GaAs

e-beam

GaAs

>>

5.Develop tri-layer stack

6.Deposition

7. Strip resist stack

Tri-Layer Process

PMMA resists for T-gate and other imaging processes

PMMA is a high resolution positive tone resist for e-beam, deep UV

(200-250nm) and X-ray lithographic processes.AlthoughPMMAmay

be used in a single layer resist process, it is most commonly used in

multi-layer processes such as in the fabrication of mushroom or

T-gates. Imagesare formed through the photo scission of the

polymer backbone and subsequent developmentprocess, which

removes the exposed, lower molecular weight resist. Multi-layer,

shaped resist profiles are realized and influenced through the careful

choice of PMMAmolecular weight, film thickness and other process

set points.

Ina typical bi-layer process, a combination of bottom and top layer

resists are selected such that a large difference in dissolution rates

of the layers at the developer step exists, leading to the desired

resist sidewall profile. Thiscontrast may be further influenced with a

varietyof process strategies. Generally,dissolution rate increases as

molecular weight decreases. However, soft bake conditions, which

affect residual solvent leveland subsequent development rates will

influence the bi-layer resist profile as will the exposure conditions.

Please refer to our web site, www.microchem.com for applications

notes concerning non-imaging PMMA processes such as wafer

thinning, bonding and sacrificial layers.

2. Coat and bake copolymer

3. Expose resist stack, center scan dose,then side scan dose

5.Deposition

6. Strip resist stack

1. Coat and bake PMMA

PMMA

GaAs

Copolymer

PMMA

GaAs

PMMA

e-beam

GaAs

4.Develop PMMA and Copolymer

>>


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NOTES

PMGI and LOR for lift-off processing

SU-8 resists for MEMS and ultra thick resist processing

Remover PG resist stripper

EBR PG edge bead remover

Acryl Strip resist stripper for PMMA

OTHER RESIST AND ANCILLORY PRODUCTS FROM MICROCHEM


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HANDLING NANO PMMA

& COPOLYMER SERIES RESISTS (in Anisole or Chlorobenz

Use precautions in handling flammablePMMA solutions. Avoidcontact w

skin, and clothing. Use with adequate ventilation.Avoidbreathing fume

chemical-resistant eye protection, chemical gloves (PVA for chloro

solutions) and protectiveclothing when handling NANOPMMA& Copolym

Resist products. NANOPMMA& Copolymer Series Resists cause irritation

of contact with eyes, skin, and mucous membranes. Incase of eye contawith water for 15 minutes and call a physician immediately. Review the

MSDS (Material Safety Data Sheet) before using.

MATERIAL AND EQUIPMENT COMPATIBILITY

NANOPMMA& Copolymer Resists are compatible with glass, ceramic

polyethylene, high-density polyethylene, polytetrafluoroethylene, stainless s

equivalent materials.

Chlorobenzene is a powerful solvent and will attack var ious elastom

as BUNAN,EPDM,HYPALON, and NEOPRENE. It will also attack PVC,Cpolyester. VITON A is recommended for both O-rings and tubing.

PROCESSING ENVIRONMENT

For optimum results, use NANO PMMA& Copolymer Series Resi

controlled environment. 20 - 25o 1oC (68 - 77oF) is suggested.

STORAGE

Store upright in original containers in a dry area 50 - 80oF (10 - 27oC). Don

refrigerate. Keepaway from sources of ignition, light, heat, oxidants, acids,

reducers. Shelf life is 13 months from date of manufacture.

DISPOSAL

Each locality, state, and county has unique regulations regarding the

of organic solventssuch as NANOPMMASeries Resists. It is the respon

the customer to dispose of NANOPMMA Series Resists in compliance

applicable codes and regulations. See MSDS for additional information.

The information regarding these products is based on our testing to date, which we believebe reliable, but accuracy or completeness is not guaranteed. We make no guarantee or warrexpressed or implied, regarding the information, use, handling, storage, or possession of thproducts, or the application of any process described herein or the results desired, since theand handling of these products are beyond our control.

MicroChem Corp. copyright 2001.

All rights reserved.

LOR is a trademark of MicroChem Corp.

1254 CHESTNUT STREET

NEWTON, MA 02464

PHONE: 617.965.5511

FAX : 617.965.5818

EMAIL: [email protected]

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pmma data sheet from microchem

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