Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 1
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.
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 2
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 3
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)
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 4
Pre CMP topography
50 um copper line, 50 um space
9 um copper line, 1 um space
0.25 um copper line, 0.25 um space
1 um copper line, 1 um space
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 5
Pre CMP topography consequence
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 6
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
60002000
5000
4000
2500
8000
30001500, 1250, 1000, 800, 600, 500, 400, 300
12500
10000
2000025000
15000
Smallfeatures
Wafer layout
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 7
60002000
5000
4000
2500
8000
30001500, 1250, 1000, 800, 600, 500, 400,300,250,200,150,125
Smallfeatures
(5mm x 4mm)
Mask layout
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 8
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 9
Wafer process
Silicon
CuTa
SiO2
TEOS
Copper Thickness is 2X trench height
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 10
Metrology
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
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 11
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 12
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 13
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))
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 14
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 15
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
Removal on the Bottom
0500
10001500200025003000350040004500
100 1000 10000 100000
Feature size (um)
Th
ickn
ess
(A) P1S1 Bottom
P2S1 Bottom
P2S2 Bottom
P3S3 Bottom
P4S4 Bottom
Removal delta Top - 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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 16
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 17
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
Feature size (microns)
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
Removal on the Bottom
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
Removal delta Top - Bottom
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 18
Process comparison
Planarization efficiency Fujimi RD-98052
0%10%20%30%40%50%60%70%80%90%
100%
100 1000 10000 100000
Feature size (microns)
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
Removal on the Bottom
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
Removal delta Top - Bottom
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
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 19
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)
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 20
Process comparison
Low Planarization Length Very high Planarization Length
Copper CMP Planarization Length - MRS 2001 - April 19th, 2001 – Paul Lefevre – Page 21
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