Better CMP Cleaning Solutions
Surfactanized Metal Inhibitors, Oxygen Scavengers
and a New Particle Remover
By
Geoffrey Yuxin Hu, PhD, Brizon Inc
Lily Yao, PhD, Western Digital Technologies Inc
March 19 2014 CMPUG 2014 San Jose
Introduction
 Challenge of CMP in IC and HD
 Background
 Classic Principle of CMP Process
 New Concepts of Slurry Chemistry and Formulation Outlet
 Fab Experimental Data and Results
 Future Developments
 Summary
 Acknowledgment
March 19 2014 CMPUG 2014 San Jose
Challenge
 Poor uniformity of the slurry on the pad
 Macro- and micro- scratching
 Residual slurry particles, Al2O3, Colloid SiO2 etal
 Trace metals and ions (Cu, Ni, Fe)
 Recontamination
 Poor re-rinsibility
 Etching, Corrosion ( aggressive chemicals,
high or low pH, and oxidation)
March 19 2014 CMPUG 2014 San Jose
Background
 Unbalanced of Hydrophilic/Hydrophobic of Surfactants
 Poor Vehicle of Slurry
 Poor uniformity of slurry on the pad
 Poor Surface modification on particles, such as SiO2
 Aggregation of particles
 Wide distribution of particles
 Macro- and micro- scratching
 Poor re-rinsibility
 Residual slurry particles, Al2O3, Colloid SiO2
March 19 2014 CMPUG 2014 San Jose
Background
 Micro incompatible of Metal Inhibitors/Oxygen Scavengers
 Un-uniform dispersion of inhibitors in the solution
 Corrosion of metal
 Recontamination
 Aggressive chemicals at high or low pH
 Corrosion
 Macro- or micro- scratching
 Poor re-rinsibility
March 19 2014 CMPUG 2014 San Jose
Classic Principle
 Higher pH (>10)
 Better removal of particles, specially BTA
 Corrosion on metal? Ni, Fe and Cu?
 Classic Non-ionic Surfactants (NIS)
 Removing particles
 Removing organic contaminations
 Ionic Surfactants (IS)
 Aliphatic phosphorous surfactants
 Metal surface protection
 Residual mono-layer
 Chelating/Complex Chemicals
 Cleaning/removing metal ions and oxides
March 19 2014 CMPUG 2014 San Jose
New Concepts
 Surfactanized Metal Inhibitors
 Hydrophilic metal inhibitor on one side
 Short aliphatic hydrophobic tail
 Maximized protection on metal, Ni, Fe and Cu
 Surfactanized Oxygen Scavenger
 Long ethoxylated hydrophilic tail
 Hydrophobic oxygen scavenger
 Max scavenged oxygen in whole CMP process
 Special Surfactants
 Ethoxylated hydrophilic tail
 Short hydrophobic chain with chelate agent
 Not ethylenediamine series
 Much better vehicle for particles, Al2O3, SiO2, etc
 Optimized and Balanced Hydrophobic/Hydrophilic Media
March 19 2014 CMPUG 2014 San Jose
Components
 Special Non-ionic Surfactants
 Mixed Surfactanized Metal inhibitors
And Oxygen Scavenger agents
 Additional Metal inhibitors
And Oxygen Scavenger agents
 Surfactanized Chelating agents
 Particle removing agents
March 19 2014 CMPUG 2014 San Jose
How it works
Hydrophilic
Metal inhibitor head
Aliphatic
Hydrophobic tail
Briteclean-0+
Briteclean-0+ : Briteclean-1 = 1:1
In 50X aqueous dilution
+
Ethoxylated
Hydrophilic Tail
Anti-oxidant
Hydrophobic Head
Briteclean-1
Briteclean-0+ : Briteclean-1 = 1:1
Bulk solution
Phase separation
March 19 2014 CMPUG 2014 San Jose
Application in a fab
 Briteclean-0+ and Briteclean-1 blended 1:1 at a total
concentration of 1.0 – 2.0% in aqueous media
 Slurry applied: in MH837/MH834/MH814 (Cabot)
 Pad applied: IC1000 (white pad --- Rodel/(Rohm Haas)
Sub IV (black pad --- Rodel (Rohm Haas))
 Tool platforms Applied: 8" Mirra (Applied Materials); 8" Ebara
(Ebara); 8" 6DS-SP(Strausbaugh)
 Wafer: Cu, Ni/Fe/Co, Low key and Al2O3
March 19 2014 CMPUG 2014 San Jose
Briteclean Products
Briteclean – 0+
Briteclean - 1
Briteclean-ACP
Pre/Post
Cleaning Process
YES
YES
YES
Slurry Additives
YES
YES
YES
Storage/Buffer
NO
NO
YES
Need to mix
Need to mix
with BC-0+
Alone
1% - 5%
1% - 5%
1% - 4%
Application with BC-1 or BC-ACP
Concentration
March 19 2014 CMPUG 2014 San Jose
Briteclean Application
8.5
8
7.85
7.5
7.2
7
6.8
6.5
pH
6.3
5.5
5
0
100%
BriteClean-1
10
20
30
40
50
60
70
Diluted 50X in DI H2O
80
90
100
100%
BriteClean-0+
Recommended Usage: Briteclean-0+/Briteclean-1 = 1:1
Diluted to 1%-5% with DI H2O
March 19 2014 CMPUG 2014 San Jose
AFM Cu Plated Wafer
BriteClean Mixture
Average Roughness(N=3x3):
Rms=0.29nm
Competitor’s Cleaning Solution
Average Roughness(N=3x3):
Rms=0.34nm
Roughness and surface residues are reduced
March 19 2014 CMPUG 2014 San Jose
SEM Cu Plated Wafer
BriteClean Mixture
Competitor’s Cleaning Solution
SEM Cu Plated Wafer
Slurry only
Slurry +
Brizon products
March 19 2014 CMPUG 2014 San Jose
Different Slurry Cleanability
BriteClean vs Competitor Particle Count
BriteClean Cleaning Solution
Con-1
Con-2
Alumina
-70
-22
NiFe
-66
-340
Competitor Cleaning Solution
Con-1
Con-2
Alumina
190
1571
NiFe
280
370
March 19 2014 CMPUG 2014 San Jose
Particle counts
BriteClean
Cleaning Solution
Alumina
NiFe
NiFe
Post
Cleaning
(PostPre)
Tool-1
259
268
9
Tool-2
692
640
-52
Tool-3
675
123
-552
Tool-4
207
78
-129
Competitor Cleaning
Solution
Alumina
Initial
(Pre-)
Initial
(Pre-)
Post
Cleaning
(PostPre)
Tool-1
477
1445
968
Tool-2
891
3065
2174
Tool-3
133
528
395
Tool-4
500
845
345
March 19 2014 CMPUG 2014 San Jose
Layer X CMP Comparison
Briteclean Application repeatability
Wafer ID Existing
Slurry
1
2
3
4
5
6
7
8
Mean Metal
ALO
Thickness
Metal WIW Thickness
Oxide WIW Added
(FEI)-O
Sigma-O
(Nano)-O
Sigma-O
Paticles
261
7.3
267
10.2
217
257
8.1
261
8.2
198
265
2.4
273
3.6
229
263
8.3
268
9.4
363
251
6.1
261
7.5
107
278
5.9
283
6.9
267
255
6.9
267
8.1
271
263
7.2
267
7.8
400
Mean
Std. Dev.
3 Sigma
261.63
7.60
22.79
6.53
1.75
5.24
268.38
6.61
19.84
7.71
1.84
5.52
256.50
86.85
260.55
278
251
27
8.3
2.4
5.9
283
261
22
10.2
3.6
6.6
400
107
293
Max.
Min.
Range
Mean Metal Thickness (FEI)-O
Wafer ID
with Brite
Additives
1
2
3
4
5
6
7
8
Mean Metal
ALO
Thickness
Metal WIW Thickness
Oxide WIW Added
(FEI)-B
Sigma-B
(Nano)-B
Sigma-B
Paticles
263
3
249
2.7
30
251
4
267
2.1
0
265
4.2
253
3
139
256
2.9
263
1.9
271
258
3.1
262
2.4
0
261
3.3
262
2.9
225
260
4.1
261
2
57
266
2.8
265
2.5
68
Mean
Std. Dev.
3 Sigma
260.00
4.64
13.91
3.43
0.54
1.63
260.25
5.72
17.15
2.44
0.39
1.16
98.75
96.27
288.82
266
251
15
4.2
2.8
1.4
267
249
18
3
1.9
1.1
271
0
271
Max.
Min.
Range
Metal WIW Sigma-O
Mean Metal Thickness (FEI)-B
Metal WIW Sigma-B
9
285
280
8
275
7
270
6
265
5
260
4
255
3
250
245
2
240
1
235
0
1
2
3
4
5
6
ALO Thickness (Nano)-O
7
8
9
10
1
2
3
4
5
6
7
8
9
10
ALO Thickness (Nano)-B
Oxide WIW Sigma-O
290
Oxide WIW Sigma-B
12
280
10
270
8
260
6
250
4
240
2
230
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
7
8
9
10
March 19 2014 CMPUG 2014 San Jose
New Developments
 Briteclean-0+
 More effective and efficiency cleaning
 Now in production in WD
 Briteclean-Cu
 Only for Cu plated wafer
 High pH value >10
 Novel agent for particle removal
March 19 2014 CMPUG 2014 San Jose
Summary
 Briteclean mixture maximizes CMP efficiency



Uniformity
Particles, metals
No recontamination
 Much improved surface roughness


New designed chemistry
Surface protection
 Much easier process
 Mixture system
 No need to change processes
March 19 2014 CMPUG 2014 San Jose
Acknowledgement
NCCAVS
Western Digital
Brizon Inc
 www.brizon.net
March 19 2014 CMPUG 2014 San Jose