WaferMasters, Inc.

New Technology for Thermal Processing

By John Foggiato

July 2003

Outline

• Issues with RTP• How WaferMasters Addressed the Issues• Various Characterized Processes• Future Directions

Dependence of Light Intensity on Temperature

Heat SourcePyrometer

Temperature Readout

0

20

40

60

80

100

0 200 400 600 800 1000 1200 1400

Temperature (oC)

Inte

nsity

(Arb

. Uni

t)

0.96µm

3.0µm

5.3µm

Wavelength

Filtered IR Imageas is

Si 0.7mm Si 2.1mmSi 1.4mm

Pyrometer3~5.3µm

Heat Source

Filter

Effect of Filters on Temperature Measurement

0

200

400

600

800

1000

1200

None

0.7mm Si

1.4mm Si

2.1mm Si

0.5mm Q

uartz

1.5mm Q

uartz

5.0mm Q

uartz

5.0mm Q

uartz

(Blas

ted)

Filter Used

Mea

sure

d Te

mpe

ratu

re (o

C)

0.96µm

3.0~5.3µmDetection Limit

for 0.96µm

Optical Properties of Si

390 µm thick

Heavily Doped Si

Lightly Doped Si

Emissivity

Absorption Coefficient

Radiation Spectra from Heated Blackbody

0

50

100

150

200

0 1 2 3 4 5 6 7 8 9 10Wavelength (µm)

Inte

nsity

(Arb

. Uni

t) 1400oC1200oC1000oC

800oC600oC400oC200oC

0

1,000

2,000

3,000

4,000

5,000

0 1 2 3 4 5 6 7 8 9 10

3000oC2750oC2500oC2250oC2000oC

1500oC1000oC

Wavelength (µm)

Inte

nsity

(Arb

. Uni

t)

0

50

100

150

200

0 1 2 3 4 5 6 7 8 9 10Wavelength (µm)

Inte

nsity

(Arb

. Uni

t) 1400oC1200oC1000oC

800oC600oC400oC200oC

Blackbody Radiation

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10Wavelength (µm)

Tran

smitt

ance

(%)

0

10

20

30

40

50

Abs

orpt

ion

Coe

ffici

ent

(cm

-1)

SiQuartz

Spectral Features in Thermal Processing

Wafer Heating MechanismRadiation vs. Conduction

W(T) = ε σ (Ta4 -Tb

4)

ε = 1.0

ε = 0.7

d = 0.2mm

d = 0.5mm

d = 1.0mm

d = 5.0mmd = 10.0mm0

50

100

150

200

250

0 200 400 600 800 1000 1200Temperature (oC)

Hea

t Flu

x (k

W/m

2 )

W(T) = λ (T) (Ta-Tb)/d

Impact of 1oC on Wafer HeatingRadiation vs. Conduction

0

200

400

600

800

1000

0 200 400 600 800 1000 1200Temperature (oC)

Effe

ct o

f 1o C

on

Hea

t Flu

x (W

/m2 )

ε = 1.0

ε = 0.7d = 0.2mm

d = 0.5mmd = 1.0mmd = 5.0mmd = 10.0mm

1. Polyimide Curing

2. Metal Anneal

3. Low-k Interlevel Dielectric

4. Curing of Photo ProcessPlanarization Materials

5. Interlayer Dielectric Densification

6. Silicide Formation

7. Gate Electrode Anneal

8. High-k Dielectric Densification

9. Thin Oxide Growth

10. Ultra-Shallow JunctionActivation and Anneal

11. Well Implant Anneal

12. Oxide Trench Fill Densification

13. Trench Oxidation andCorner Rounding

14. SOI Splitting

1. Polyimide Curing

2. Metal Anneal

3. Low-k Interlevel Dielectric

4. Curing of Photo ProcessPlanarization Materials

5. Interlayer Dielectric Densification

6. Silicide Formation

7. Gate Electrode Anneal

8. High-k Dielectric Densification

9. Thin Oxide Growth

10. Ultra-Shallow JunctionActivation and Anneal

11. Well Implant Anneal

12. Oxide Trench Fill Densification

13. Trench Oxidation andCorner Rounding

14. SOI Splitting

Applications of RTP in Semiconductor Device Manufacturing

How WaferMasters, Inc. Addressed Issues

• Isothermal Chamber-No backside pattern effects• Utilized Natural Characteristics of Wafers’ Thermal

Capacity• Wafer Handling• Wafer Temperature Control/Uniformity• No Moving parts-Contamination Control• Small Footprint and Low Power and Gas

Consumption

Load lock O2 + N2

Exhaust

Zone 1 Zone 2 Zone 3

Thermal Insulator 1

Thermal Insulator 2

Heating ElementsHeat Diffuser

TC for Wafer Temp. Monitoring

TC1 TC3TC2

Temperature Controller

Zone 1 Power

Zone 2 Power

Zone 3 Power

Data

Computer

Thermal Insulator

• Resistive Heating • Minimum Aperture (d << W, d << L)• Nearly Isothermal Cavity• No Moving Parts• Zone Temp. Control• Heat Diffuser• Wafer Temp. Monitoring

Process Module of High Temperature SRTF

AGVInterface

Vacuum Loadlock

Robot

ProcessChambers

Single Wafer Rapid Thermal Furnace Configuration

Chamber 2

Chamber 1

Cooling Stations

Robot

New orProcessedCassettes

VacuumPump

Configuration of Lower Temperature Chambers

Process Module- Stacked Hot Plates

Vacuum Robot- Extended z-axis travel

Load Port- Triangular door

Cassette Stage- Cooling stations

Optical Bench- No adjustment

Vacuum Pump- Integrated

X-ray Topography with Optimal End Effector Wafer Processed 5 times at 1100oC, 60s under 1 atm air

a

d

b

c

slipslipstandoff

end effector

standoff

System Configurations for Metal Silicide Formation

SRTF-200LP-No moving parts in process chamber-Temperature range : 200 – 1100oC

20mm gap

Cooling stations

Wafer cassette

RobotProcess chamber

Aluminum hot plate

Wafer

9mm-longstandoffs

SAO-200LP-Individually controlled heater element -Temperature range : 100 – 550oC

Wafer Heating and Cooling Capability

Process Time

0

200

400

600

800

1000

1200

0 60 120 180 240 300 360Time (s)

Waf

er T

empe

ratu

re (o

C)

Natural Cooling

Wafer In Wafer Out

Forced Cooling in Cooling Station

0

500

1000

1500

2000

2500

3000

3500

700 800 900 1000 1100 1200Temperature Set Point (oC)

Pow

er C

onsu

mpt

ion

(W) Total

Zone 1

Zone 2

Zone 3

Low Power Consumption

Thermal Product Road Map150 to 300 mm wafers

H2 Anneal

Silicidation (2nd step)Film Densification

Process TimeMomentary

Tem

pera

ture

(o C)

1200

1000

800

600

400

200

RT

SRTF

1 min 5 min 10 min 20 min 30 min

SAO

MBF

Flash

DCH

Oxidation

Nitridation

Ta2O5 Deposition

Ta2O5 Recrystallization

SOG/SOD Anneal

Al Sintering

Glass Reflow

Cu Anneal

SOI Splitting

Wafer Bumping

Implant AnnealUSJ AnnealUSJ Anneal

Silicidation (1st step)

Photoresist Bake

Flash: Flash Annealing SystemSRTF: Single Wafer Rapid Thermal Furnace (Sold Through TEL)DCH: Direct Contact Hot Plate SystemSAO: Stacked Annealing OvenMBF: Mini Batch Furnace

Typical Process Uniformity

Dry Oxidation

12.854 ohm/sq 2.150%Unif. Change 0.578%

86.63 ohm/sq 0.39%2.9 nm 0.67%

600oC60s

800oC60s

0.953 ohm/sq 1.624%Unif. Change 0.151%

(a) (b)

(c) (d)

TiSi2 Ti2Si

75As+ Implant Anneal Oxide

1100 oC35s

1000oC100s

TiSi2 Formation Ti2Si Formation

Implant Anneal75As 70keV 1E15

200mm Stacked Annealing Oven

600mm (W) X 1200mm (D) X 1700mm (H) (2 ft X 5 ft X 6 ft)

SRTF-300AP System

Various Characterized Processes

• Ion Implant– Boron, BF2 and with amorphization Species– Phosphorus and Arsenic

• BPSG Reflow• Silicide Formation

– TiSi, CoSi, NiSi• Low Temperature Anneals

– Copper– SOG

• Film Growth– Oxide, Nitride

• Defect Engineering

SIMS Profiles of 35sec ProcessTemperature dependence

1KeV, 5E14 ions/cm2 11B+ implant

1.E+17

1.E+18

1.E+19

1.E+20

1.E+21

1.E+22

0 20 40 60 80 100 120 140Depth (nm)

B C

once

ntra

tion

(ato

ms/

cm3)

As implanted 950degC 35s1000degC 35s1050degC 35s1100degC 35s

1KeV, 1E15 ions/cm2 11B+ implant

1.E+17

1.E+18

1.E+19

1.E+20

1.E+21

1.E+22

0 20 40 60 80 100 120 140Depth (nm)

B C

once

ntra

tion

(ato

ms/

cm3)

As implanted

950degC 35s

1000degC 35s

1050degC 35s

Ion Implant Anneal Process Window ComparisonUniformity <0.5%(1σ)

ρs(Ω/sq.) Uniformity(%)

B+ 50KeV, 1E15 atoms/cm2 BF2+ 70KeV, 1E15 atoms/cm2

ρs(Ω/sq.) Uniformity(%)

Sheet Resistance <90(Ω/sq.) Sheet Resistance <110(Ω/sq.)

As+ 70KeV, 1E15 atoms/cm2 P+ 70KeV, 1E15 atoms/cm2

ρs(Ω/sq.) Uniformity(%) ρs(Ω/sq.)Uniformity(%)

Uniformity(%)Sheet Resistance <68(Ω/sq.)Sheet Resistance <92(Ω/sq.)

Typical Implant Anneal Process Uniformity

31P 70keV 1E15

BF2 70keV 1E15 75As 70keV 1E15

11B 50keV 1E15

Ave.= 86.63Ω/sq.1σ= 0.95Ω/sq.

Unif.= 0.39%(1σ)

Ave.=103.19Ω/sq.1σ= 0.31Ω/sq.

Unif.= 0.30%(1σ)

Ave.= 65.05Ω/sq.1σ= 0.16Ω/sq.

Unif.= 0.25%(1σ)

Ave.= 89.46Ω/sq.1σ= 0.37Ω/sq.

Unif.= 0.41%(1σ)

1050oC, 35s1000oC, 35s

1100oC, 35s 1000oC, 35s

Implant Anneal Summary

SWF 40s

50

100

150

200

250

300

850 900 950 1000 1050 1100 1150Temperature (oC)

Shee

t Res

ista

nce

(Ohm

/sq.

)

75As+

31P+

49BF2+

11B+Lamp RTP 10s

50

100

150

200

250

300

850 900 950 1000 1050 1100 1150Temperature (oC)

Shee

t Res

ista

nce

(Ohm

/sq.

)

75As+

31P+

49BF2+

11B+

0.02.04.06.08.0

10.012.0

850 900 950 1000 1050 1100 1150Temperature (oC)

Rs

Uni

form

ity (%

)

0.02.04.06.08.0

10.012.0

850 900 950 1000 1050 1100 1150Temperature (oC)

Rs

Uni

form

ity (%

)

75As+ 70keV 1E1531P+ 70keV 1E1549BF2

+ 70keV 1E1511B+ 50keV 1E15

11B+ Implant Anneal

Lamp RTP SWF

0

1

2

3

4

5

6

7

0 100 200 300 400 500Depth (nm)

Bor

on C

once

ntra

tion

(x10

19at

oms/

cm3 )

11B+ 50keV, 1E15 cm-2

As implanted40s 264.09 Ω/sq.

180s 169.45 Ω/sq.

900oC

40s 108.67 Ω/sq.100s 88.64 Ω/sq.180s 86.94 Ω/sq.

40s 86.09 Ω/sq.100s 85.66 Ω/sq.180s 86.27 Ω/sq.

1000oC

1100oC

0

1

2

3

4

5

6

7

0 100 200 300 400 500Depth (nm)

Bor

on C

once

ntra

tion

(x10

19at

oms/

cm3 ) As implanted

10s 236.78 Ω/sq.150s 158.39 Ω/sq.

10s 101.14 Ω/sq.70s 88.58 Ω/sq.

150s 86.70 Ω/sq.

10s 86.92 Ω/sq.70s 87.79 Ω/sq.

150s 90.22 Ω/sq.

1100oC

1000oC

900oC11B+ 50keV, 1E15 cm-2

49BF2+ Implant Anneal

Lamp RTP SWF1100oC

0 0 100 200 300 400 500

Depth (nm)

Bor

on C

once

ntra

tion

(x10

19at

oms/

cm3 )

5

10

15

20

25

1100oC40s 104.33 Ω/sq.55s 105.91 Ω/sq.70s 107.41 Ω/sq.

100s 110.02 Ω/sq.140s 112.53 Ω/sq.180s 116.00 Ω/sq.

49BF2+ 70keV, 1E15 cm-2

As implantedAs implanted

1100oC

0 0 100 200 300 400 500

Depth (nm)

Bor

on C

once

ntra

tion

(x10

19at

oms/

cm3 )

5

10

15

20

2549BF2

+ 70keV, 1E15 cm-2

10s 109.80 Ω/sq.25s 130.22 Ω/sq.40s 146.43 Ω/sq.70s 194.04 Ω/sq.

110s 207.53 Ω/sq.150s 215.88 Ω/sq.

BPSG Film Densification/Reflow

0.0

1.0

2.0

3.0

4.0

5.0

Thic

knes

s Sh

rinka

ge (%

)1000ºC

950ºC

900ºC

850ºC

800ºC

750ºC

700ºC

650ºC

600ºC

-0.5

0.0

0.5

0 50 100 150 200Annealing Time (s)

∆U

nif.

(%)

Maximum density reached with highest shrinkage

0

10

20

30

40

50

60

70

500 600 700 800 900 1000Temperature (oC)

Post

Rs

(Ohm

/sq.

)60s 90s 120s

Titanium Silicide Formation and Anneal700 Torr, N2 Atmosphere, Ti = 35nm

0

0.5

1

1.5

2

2.5

500 600 700 800 900 1000Temperature (oC)

Rs

Cha

nge

Rat

io

60s 90s 120s

3

Temperature Sensitivity for CoSi Formation

172.0

6.7 5.1

95.292.497.384.5

135.7

020406080

100120140160180200

350 400 450 500 550 600 650 700Temperature (oC)

Rs

(ohm

/sq.

)

10nm TiN capped 10nm CoAnnealing time = 120secAfter SPM cleaning

CoxSi Formation (10nm TiN capped 10nm Co) Process conditions : 425oC, 150sec, After SPM cleaning

-100

-80

-60

-40

-20

0

20

40

60

80

100

-100-80 -60 -40 -20 0 20 40 60 80 100-100

-80

-60

-40

-20

0

20

40

60

80

100

-100-80 -60 -40 -20 0 20 40 60 80 100 68

70

72

74

76

78

80

-100

-80

-60

-40

-20

0

20

40

60

80

100

-100-80 -60 -40 -20 0 20 40 60 80 100

Slot #01 Slot #15 Slot #23

Average : 74.2 ohm/sqMaximum : 77.4 ohm/sqMinimum : 70.6 ohm/sqUniformity : 2.25%

Average : 73.6 ohm/sqMaximum : 79.2 ohm/sqMinimum : 69.0 ohm/sqUniformity : 2.28%

Average : 73.2 ohm/sqMaximum : 79.0 ohm/sqMinimum : 69.3 ohm/sqUniformity : 2.62%

Wafer to Wafer Repeatability (Max-Min)/2Ave =±0.68%

001018 001018 001018

Oxide Thickness vs. Oxidation TimeO2=0.5SLM, 760Torr

0

5

10

15

20

25

30

35

40

0 100 200 300 400Time (s)

Oxi

de T

hick

ness

(nm

) 1150°C

1100°C

1075°C1050°C1025°C1000°C

Typical Thin Dry Oxide Films

1000oC, 100s, 760TorrO2=0.3slm, N2 = 2.7slmAverage = 2.9nm, Unif.= 0.67%

1000oC, 100s, 760TorrO2=0.5slm, N2 = 0slmAverage = 5.3nm, Unif.= 0.91%

1000 Wafer Marathon Run

3.0

3.5

4.0

4.5

5.0

5.5

6.0

10.0

1.0

2.0

3.0

4.0

5.0

6.0

ThicknessUniformity

1000oC, 100sO2 = 0.5slm, 760Torr

Ave

rage

Oxi

de T

hick

ness

(nm

)

Run Number

Thic

knes

s U

nifo

rmity

(%)

250 1000750500

• Extremely Repeatable- Thickness: 0.8% (1σ)- Uniformity

Wafer Temperature Ramp Up Profile

050

100150200

250300350400450

0 60 120 180 240 300Time (s)

Waf

er T

empe

ratu

re (o C

)

He Air

Standoff Height

8 mm

Hot Plate

Hot Plate

HeaterWafer

Standoffs

0

5

10

15

20

25

150 200 250 300 350 400 450Temperature (oC)

Ave

. Thi

ckne

ss S

hrin

kage

(%)

1 min3 min5 min

0

5

10

15

20

25

30

35

150 200 250 300 350 400 450Temperature (oC)

Uni

form

ity o

f Shr

inka

ge (%

)

1 min

3 min5 min

1.370

1.380

1.390

1.400

1.410

1.420

1.430

1.440

150 200 250 300 350 400 450Temperature (oC)

Ref

ract

ive

Inde

x 1 min

3 min

5 min

SOG Anneal Process Trends

1.360

1.370

1.380

1.390

1.400

1.410

1.420

1.430

1.440

0 5 10 15 20 25Average Thickness Shrinkage (%)

Ref

ract

ive

Inde

x

0

1

2

3

4

5

6

7

8

Uni

form

ity C

hang

e (%

)

Particle Performance

0123456789

10

0 50 100 150Run Number

No.

of P

artic

les

Add

ed

Slot 1Slot 2Slot 3Slot 4Slot 5

>0.2µm

Stacked Annealing Oven (SAO-200LP) for Cu, NiSi and low K Dielectrics Applications

Process Module- Stacked Hot Plates

Vacuum Robot- Extended z-axis travel

Load Port- Triangular door

Cassette Stage- Cooling stations

Optical Bench- No adjustment

Vacuum Pump- Integrated

Surface Response of Rs Reduction Ratio

3 µm 5.5 µm

Cu Anneal in Forming Gas

Cu Grain Growth by Annealing

400oC, 5 min300oC, 5 min200oC, 5 min

Cu Thickness = 3.0 µm 1 atm forming gas

NiSi Sheet Resistance Changes between Pre and Post-annealing

-Silicidation in SAO was obtained at temperatures from 350oC to 550oC with TiN uncapped samples on as well as capped samples.-Increasing sheet resistance was observed above 600oC, 650oC was already too high to form stable NiSi.

SRTF-preSRTF-postSAO-preSAO-post

She

et R

esis

tanc

e (Ω

/sq)

0

10

20

30

40

50

200 300 400 500 600 700Heater temperature (oC)

239Ω/sq 238Ω/sq

SAO

SRTF

-Reflectance indicates film transformation confirmed by sheet resistance changes.

Reflectance Properties of NiSiAfter Formation at Various Temperatures

0.2

0.3

0.4

0.5

0.6

0.7

200 300 400 500 600 700 800

Wavelength (nm)

Ref

lect

ance

SAO 250CSAO 300CSAO 350CSAO 450CSAO 550CSRTF 600CSRTF 650CSRTF 700C

Showed lowered Rs

Surface Roughness - AFM Image

200oC→450oC 250oC→450oC 450oC

Rs= 8.0 Ω/sq. Rs= 8.0 Ω/sq. Rs= 8.7 Ω/sq.Unif.= 4.59 % Unif.= 4.66 % Unif.= 5.01 %

Ra= 0.142 nm Ra= 0.129 nm Ra= 0.130 nmRz= 1.284 nm Rz= 1.187 nm Rz= 1.207 nm

SAO-Capped

3.0nm 3.0nm3.0nm

TiN/Ni(90A)/Si-sub

Flash Anneal System Concept

• Motivation : USJ formation (Shallow implantation is a must!)– Maximum electrical activation– Least amount of diffusion

• Light Source : Short wavelength, high intensity light pulse– Xe arc lamp– Photon energy distribution

• Wafer Temperature : Mainly surface heating– Surface vs. Bulk– Time dependence

Spectral Emission of Lamps

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0Wavelength (µm)

0

2.0

Inte

nsity

(Arb

. Uni

ts)

1.5

0.5

1.0

0

4E5

6E5

8E5

1E6

α(c

m-1

)

α

Xe ArcLamp

Tungsten-halogen Lamp

2E5

3000oC

2500oC

2000oC

Illustration of Wafer Temperature Profile

Time (s)

0

200

400

600

800

1000

1200

1400

1600

-1.0 0.0 1.0 2.0 3.0

Surf

ace

Tem

pera

ture

(oC

) HighMediumLow

Surface Temperature vs. Power

Flash

Power

0

200

400

600

800

1000

1200

1400

1600

Surface BacksideDepth

Tem

pera

ture

(oC

)

Flash

Bulk Temperature vs. Time

t1

t2

t3

t1 < t2 < t3Time

Time

Implant Species: 49BF2+

Implant Energy: 3keVImplant Dose: 1.0x1015cm-2

Surface Condition: 1.0~1.5nm Chemical SiO2

Amorphorized Layer Thickness: ~10nm

49BF2+, 3keV, 1 x1015cm-2

Spike Anneal

0

200

400

600

800

1000

1200

1 2 3 4 5Annealing Conditions

Shee

t Res

ista

nce

(ohm

/sq.

)USJ Implant Anneal

Flash

USJ Implant Anneal11B+, 49BF2

+ Various Implant and Annealing Conditions

10

100

1000

10000

0 10 20 30 40 50 60 70 80 90 100Junction Depth xj (nm)

Shee

t Res

ista

nce

(Ohm

/sq.

)

1.0x1019

CrystallinePre-amorphized

Flash

RTA

Combination

2.0x1019

5.0x1019

1.0x1020

2.0x1020

Carrier concentration(cm-3)

90 n

m90

nm

80 n

m80

nm

70 n

m70

nm

65 n

m65

nm

130

nm13

0 nm

100

nm10

0 nm

ITR

S 20

02IT

RS

2002

USJ Implant Anneal with Flash

7s, 174.1 Ω /sq.6s, 176.1 Ω /sq.

1017

1018

1019

1020

1021

1022

0 50 100 150 200 250 300Depth (nm)

B C

once

ntra

tion

(ato

ms/

cm3 )

2s, 2748.1 Ω /sq.3s, 1167.6 Ω /sq.4s, 787.2 Ω /sq.5s, 263.3 Ω /sq.

800oC, 25s 22906 Ω /sq.

1684.8 Ω /sq.

+ 1s CW1236.5 Ω /sq. + 2s CW

0 20 40 60 80 100Depth (nm)

402.2 Ω /sq.

1017

1018

1019

1020

1021

1022

B C

once

ntra

tion

(ato

ms/

cm3 )

+ Flash

11B+ 1keV 1 x 1015 cm-2

Lamp Only (CW) Hot Plate + Lamp

Summary

• Developed RTP technology based on natural characteristics of wafer

• Demonstrated equivalent processes for ion implant anneal as obtained with lamp based RTP

• System operation insensitive to emissivity characteristics of wafer and wafer surface

• Temperature operation over wide temperature range• New FLASH technology for USJ demonstrated