copper cmp planarization length - mrs 2001 - april 19 th, 2001 – paul lefevre – page 1 direct...

Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre –

DIRECT MEASUREMENT OF PLANARIZATION LENGTH FOR COPPER CHEMICAL MECHANICAL POLISHING (CMP) PROCESSES USING A LARGE PATTERN TEST MASK.

Paul Lefevre, Albert Gonzales, Tom Brown, Gerald Martin,International SEMATECH, Austin, TX;

Tamba Tugbawa, Tae Park, Duane Boning, Microsystems Technology Laboratories, MIT, Cambridge, MA;

Michael Gostein, Philips Analytical, Natick, MA;

John Nguyen, SpeedFam-IPEC, Phoenix, AZ.


Agenda

• Introduction

• Pre CMP topography

• International Sematech / MIT Mask 862 design

• Wafer process and metrology

• Planarization Length definition

• Planarization Length on different process

• Planarization Length on different consumables

• Conclusion


Introduction

• Visual observation copper residue are more or less pattern dependent (Qualitative)

• Feature size design / Pre CMP topography size

• Develop a direct qualitative method for planarization distance measurement.

• Help industry with having access to this mask International Sematech / MIT 862 (Semiconductor and CMP suppliers)


Pre CMP topography

50 um copper line, 50 um space


0.25 um copper line, 0.25 um space



Pre CMP topography consequence


60002000

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30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

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30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

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8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

12500

10000

2000025000

15000

Smallfeatures

Wafer layout


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5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400,300,250,200,150,125

Smallfeatures

(5mm x 4mm)

Mask layout


Line width = 100;Line space = 1, 3, 5, 10, 15, 20, 30, 50, 75, 100(1.309 mm x 1.200 mm)

Line width = 50;Line space = 1, 3, 5,10, 15, 20, 30, 50, 75,100(0.809 mm x 1.200mm)

100, 80, 60, 50, 40,30,25,20,15,12.5,10,8,6,5,4,3, 2.5,2,1.5,1.25,1

Line width = 20;Line space = 1,3, 5, 10, 15, 20,30, 50, 75, 100(0.509 mm x1.200 mm)

Line width =15;Line space= 1, 3, 5,10, 15, 20,30, 50, 75,100(0.459 mmx 1.200mm)

Line width= 10;Linespace = 1,3, 5, 10,15, 20, 30,50, 75,100(0.409 mmx 1.200mm)

Linewidth =5;Linespace =1, 3, 5,10, 15,20, 30,50, 75,100(0.359mm x1.200mm)

Linewidth =1;Linespace= 1, 3,5, 10,15, 20,30, 50,75,100(0.319mm x1.200mm)

Line width = 1, 1.5, 3, 5, 10, 15, 30, 50, 100

Line lenght = 1, 1.5, 3, 5, 10, 15, 30, 50, 100, 150, 300,500, 1000(1.815 mm x 3.965 mm)

Small features(5mm x 4mm)

Small structures


Wafer process

Silicon

CuTa

SiO2

TEOS

Copper Thickness is 2X trench height


Metrology

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30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

60002000

5000

4000

2500

8000

30001500, 1250, 1000, 800, 600, 500, 400, 300

12500

10000

2000025000

15000

Smallfeatures

Measurementsperformed on Philips Impulse 300

15 measures perStructure-5 left-5 center-5 right


ResultsThickness removed in the bottom area

0

1000

2000

3000

4000

5000

6000

7000

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

rem

ove

d (

A) 1, 853A

2, 2111A

3, 3400A

4, 3400A

5, 4848A

6, 5748A

Copper removal Delta Top - Bottom

0

1000

2000

3000

4000

5000

6000

100 1000 10000 100000

Feature size (um)

Del

ta C

oppe

r th

ickn

ess

(A)

1, 853A

2, 2111A

3, 3400A

4, 3400A

5, 4848A

6, 5748A

Planarization efficiency

0%

20%

40%

60%

80%

100%

120%

100 1000 10000 100000

Feature size (microns)

Pla

nari

zatio

n ef

ficie

ncy

in

% (1

- R

R b

ot /

RR

top)

1, 853A

2, 2111A

3, 3400A

4, 3400A

5, 4848A

6, 5748A

Thickness removed in the top area

0

1000

2000

3000

4000

5000

6000

7000

100 1000 10000 100000

Feature size (um)

Thic

knes

s re

mov

ed (A

)

1, 853A

2, 2111A

3, 3400A

4, 3400A

5, 4848A

6, 5748A

Top - Bottom PE = 1 – Bottom / Top


ResultsCopper removal Delta Top - Bottom

0

1000

2000

3000

4000

5000

6000

100 1000 10000 100000

Feature size (um)

Del

ta C

oppe

r th

ickn

ess

(A)

1, 853A

2, 2111A

3, 3400A

4, 3400A

5, 4848A

6, 5748A

Minimum Planarization Length Maximum Planarization Length

Average planarization Length

Log Scale


Planarization LengthsAverage Planarization Length

Maximum Planarization Length = Minimum Feature size were removal bottom equal removal topOr Maximum Planarization Length = Minimum Feature size were planarization Efficiency is zero

Minimum Planarization Length = Maximum Feature size where removal bottom is zeroOrMinimum Planarization Length = Maximum Feature size where planarization efficiency is 1

Average planarization Length = (Min PL) x (Max PL)

Average Planarization Length on a Log scale diagram is = Exp ( Average (Min PL, Max PL))


Consumable comparisonRemoval on the Top

0500

10001500200025003000350040004500

0 5000 10000 15000 20000 25000 30000

Feature size (um)

Th

ickn

ess

(A) P1S1 Top

P2S1 Top

P2S2 Top

P3S3 Top

P4S4 Top

Removal on the Bottom

0500

10001500200025003000350040004500

0 10000 20000 30000

Feature size (um)

Th

ickn

ess

(A) P1S1 Bottom

P2S1 Bottom

P2S2 Bottom

P3S3 Bottom

P4S4 Bottom

Removal delta Top - Bottom

0500

10001500200025003000350040004500

0 5000 10000 15000 20000 25000 30000

Feature size (um)

Th

ickn

ess

(A) P1S1 Delta

P2S1 Delta

P2S2 Delta

P3S3 Delta

P4S4 Delta

Planarization Efficiency

0%

20%

40%

60%

80%

100%

0 5000 10000 15000 20000 25000 30000

Feature size (um)

Eff

icie

ncy

(%

) P1S1 PE

P2S1 PE

P2S2 PE

P3S3 PE

P4S4 PE


Consumable comparisonRemoval on the Top

0500

10001500200025003000350040004500

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

(A) P1S1 Top

P2S1 Top

P2S2 Top

P3S3 Top

P4S4 Top


0500

10001500200025003000350040004500

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

(A) P1S1 Bottom

P2S1 Bottom

P2S2 Bottom

P3S3 Bottom

P4S4 Bottom


0500

10001500200025003000350040004500

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

(A) P1S1 Delta

P2S1 Delta

P2S2 Delta

P3S3 Delta

P4S4 Delta

Planarization Efficiency

0%

20%

40%

60%

80%

100%

100 1000 10000 100000

Feature size (um)

Eff

icie

ncy

(%

) P1S1 PE

P2S1 PE

P2S2 PE

P3S3 PE

P4S4 PE


Consumable comparison

Process Slurry Max PL Min PL Av. PL

Symbol Type (um) (um) (um)

P1S1 4 75 75 A Stacked Rotary 9000 1250 3354P2S1 4 75 75 A Solo Rotary 28000 1250 5916P2S2 4 75 75 B Solo Rotary 39690 1250 7044P3S3 2 100 100 C Stacked Rotary 39690 2000 8910P4S4 D Solo** Orbital 50009 1000 7072

Tool Type

Down Force (psi)

Carrier Speed (rpm)

Table Speed (rpm)

Pad Type


Process comparison

Planarization efficiency Fujimi RD-98052

0%10%20%30%40%50%60%70%80%90%

100%

0 5000 10000 15000 20000 25000 30000


Pla

nar

izat

ion

eff

icie

ncy

in %

(1

- R

R b

ot /

RR

top

) 12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn

Removal on the Top

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 10000 20000 30000

Feature size (um)

Th

ickn

ess

(A)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 5000 10000 15000 20000 25000 30000

Feature size (um)

Th

ickn

ess

(A)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


0

500

1000

1500

20002500

3000

3500

4000

4500

0 10000 20000 30000

Feature size (um)

Th

ickn

ess

(A)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


Process comparison

Planarization efficiency Fujimi RD-98052

0%10%20%30%40%50%60%70%80%90%

100%

100 1000 10000 100000


Pla

nar

izat

ion

eff

icie

ncy

in %

(1

- R

R b

ot /

RR

top

) 12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn

Removal on the Top

0

500

1000

1500

2000

2500

3000

3500

4000

4500

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

(A)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


0

500

1000

1500

2000

2500

3000

3500

4000

4500

100 1000 10000 100000

Feature size (um)

Th

ickn

ess

(A)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


0

5001000

1500

2000

25003000

35004000

4500

100 1000 10000 100000

Feature size (um)

Thic

knes

s (A

)

12 ooo

13 ppp

14 ppn

15 pnp

16 pnn

17 npp

18 npn

19 nnp

20 nnn


Process comparison

ProcessSlurry flow

Slurry Pad TypeTool Type

Max PL Min PL Av. PL

Symbol (ml/min) Type (um) (um) (um)

ooo 2 65 65 125 C Stacked Rotary 20000 2000 6325ppp 3 100 100 200 C Stacked Rotary 12500 2000 5000ppn 3 100 100 50 C Stacked Rotary 12500 2000 5000pnp 3 30 30 200 C Stacked Rotary 8000 2000 4000pnn 3 30 30 50 C Stacked Rotary 8000 2000 4000npp 1 100 100 200 C Stacked Rotary 39375 3000 10869npn 1 100 100 50 C Stacked Rotary 39375 3000 10869nnp 1 30 30 200 C Stacked Rotary 39375 2500 9922nnn 1 30 30 50 C Stacked Rotary 39375 2500 9922

Down Force (psi)

Carrier Speed (rpm)

Table Speed (rpm)


Process comparison

Low Planarization Length Very high Planarization Length


Conclusion

• New International Sematech / MIT mask 862 allow a direct measure of planarization Length

• Definition of Planarization Length

• Wafers mask 862 available – In public domain

copper cmp planarization length - mrs 2001 - april 19 th, 2001 – paul lefevre – page 1 direct...

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