Advanced Slurry/Pad Technologies for Cu/Low-K CMP Process...1200 1400 1600 Fumed silica Colloidal...
Transcript of Advanced Slurry/Pad Technologies for Cu/Low-K CMP Process...1200 1400 1600 Fumed silica Colloidal...
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Advanced Slurry/Pad Technologies for Cu/Low-K CMP Process
JSR Confidential 2
Contents
CMP requirements for 65nm and beyondConcepts of JSR Soft polishingApproach from slurry improvement
Soft-brasiveTM TechnologiesOptimization of ingredient chemicals
Approach from pad improvementFiller Pad Technology
Results of slurry/pad combinationConclusions
JSR Confidential 3
General Requirementto CMP process for 65nm-generation and beyond.
Soft polishing to prevent damage of delicate film stack and structure with low-k dielectric materialsHigher planarity…Low dishing / erosionFaster bulk polishing for higher through-putLow defects
JSR Confidential 4
Causes of Scratch
Contamination of large particlesUncontrolled shape and morphology of abrasivesUncontrolled surface status of padScum (cleanliness)Coagulation and precipitation of ingredients and polished materials by
sudden pH change during the processUnnecessarily high down-force
JSR Confidential 5
Requirement for Cu/Low-K CMP Process
Cu wiring
Low-K dielectrics
Pad
Slurry
Dishing Erosion
Scratch Peeling
Minimal Low-K Damage and Less Scratches High Planarity ・ Fast Removal Rate
Approach by Slurry/Pad Technology
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Soft-brasive Technologies
Polymer Abrasives Colloidal Silica Abrasives
Composite Abrasives
Totally controlled shape and morphologyMinimized large particle formation by
well-established production processCushion effect to local high down-force
JSR Confidential 7
945
72 29 10 0123 31 5 3 00
200400600800
1000120014001600
Fumed silica Colloidalsilica
Compositeabrasive A
Compositeabrasive B
Polymerabrasive
Cou
nt /
waf
er ScratchPeeling
Scratch Counts by Various AbrasivesLKD : JSR LKD(k=2.2) CMP machine : EPO112 Defect measurement : KLA2112
65235760625945TaN-RR (A/min)
Polymer abrasive
Composite abrasive B
Composite abrasive A
Colloidal silica
Fumed silica
Soft-brasiveTM Technologies accomplish less scratches and Low-K damages.
JSR Confidential 8
High Performance Cu Slurries
ChemicalsFor scratch prevention
Stabilization of polished material to prevent coagulation and precipitation
For high planarity / fast removal rateControlling the etching rate to prevent dishing and erosion.Controlling the strength of passivation layer on the Cu surface.
JSR CMS7400/8400 series
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Dishing/Erosion Performance with Over Polish Margin (Cu Polish)
0
200
400
600
800
1000
0 20 40 60 80 100 120
Over Polish (%)
Dis
hing
/Ero
sion
(A)
100umDishing120umPadDishing4.5/0.5umErosion0.35/0.35umErosion
CMS7400 series exhibit excellent Dishing/Erosion performance with wide over polish margin.
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Down Force Dependency
0
400
800
1200
0 5
Down force (psi)
Cu
rem
oval
rate
(nm
/min
)
CMS7400
Conventionalslurry
CMS7400 series shows smaller down force dependency.
Low Down Force Polishing!!
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Innovative Technology of JSR CMP Pads
When exposed to polishing liquids, the water soluble particles (WSP) at the pad surface dissolve, forming micro pores.
WSP in the pad bulk remains solid so the pad maintains a very low compressibility providing superior planarizationefficiency and consistent pad-to-pad quality
The size, shape and distribution of the pores are well-controlled, being directly related to WSP particle size, shape and dispersion.
JSR’s Innovative Solid Pad
Micro PoresMatrix Polymer
Dressing
Water Soluble Particles (WSP)
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Low Defect & Good Planarity Concept
Bad Planarity
Good Defect Performance
Hard
Soft
Good Planarity
Less Defect
=
=
JSR CMP PadSolid pad with WSP
Good Planarity
Bad Defect Performance
Soft PadHard Pad
JSR Pad: Excellent defect performance without sacrificing RR/Planarity performance.
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Hardness vs. Scratch
0
10
20
30
40
50
60
65 67 69 71 73
Hardness
Scra
tch
Cou
nts
(KLA
Ste
alth
) P-TEOS Blanket Wafer Polish
Reduction of the hardness affects the scratch counts
Soft Polishing!!
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Hardness vs Removal Rate
500
600
700
800
900
60 65 70 75
Hardness
Cu R
emov
al R
ate
(nm
/min
.) Down Force = 2.9 psi
2.2 psi
1.5 psi
Cu Blanket Wafer Polish
Surface micro pore structure maintains the constant removal rate over the variation of hardness.
JSR Confidential 15
WSP amount vs. Hardness/Planarity
0
20
40
60
80
100
1 2 3
WSP amount (normalized)
Har
dnes
s
400
500
600
700
800
LSH
(A)
The polymer matrix reinforced by WSP gives wide margin of planarity over the deviation of bulk hardness.
SKW-7 Pattern Wafer Polish
JSR Confidential 16
Polishing conditionsPolisher: Mirra MesaSlurry: JSR Barrier Slurry
Defect evaluationSP1 tbiLow throughputHigh Sensitivity recipe(calibrated on silicon):
CMP Pad Defect ComparisonBarrier Slurry Evaluation
Copper Blanket Wafer Defect (SP1 DCO)
0
5000
10000
15000
20000
25000
Conventionalhard pad
Conventional Soft Pad
JSR Std JSR Soft
Pad Type
SP
1 D
CO
Def
ect C
ount
s
The defect level of JSR pads is more than 10x less than conventional hard pad.Defect level of JSR soft pads are close in performance to conventional soft pad.
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Dishing/Erosion Comparison
• JSR pads show better topography correction compared with conventional soft pad.
• JSR standard and soft pads show comparable performance.
4.5/0.35 Erosion (Mask831)
0
50
100
150
200
250
300
0 10 20 30 40 50 60 70 80 90 100
Polish Time [ sec ]
Eros
ion
[ A ]
St'd (1.5/0.5/1.4)St'd (3.0/0.5/1.4)JSR Soft PadJSR Very Soft PadConventional Soft
100/100 Dishing (Mask831)
0
50100
150
200
250
300
350
400
0 10 20 30 40 50 60 70 80 90 100Polish time [ sec ]
Dis
hing
[ A
]
St'd Pad (1.5/0.5/1.4)St'd (3.0/0.5/1.4)JSR Soft PadJSR Very Soft PadConventional Soft
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CMP Process for Cu/Low-K
Scratch and Low-K Damage
Filler Pad Technology
High Planarity
JSR CMS7400/8400 series
Advanced Cu/Low-K CMP Process
JSR Confidential 19
Cu CMP using CMS7400/Filler Pad
160Dishing [A] (120um pad)
116
279
404
20
127
1.8
10,020
Cu Polish
Erosion [A] (L/S=0.35/0.35)
Erosion [A] (L/S=4.5/0.5)
Dishing [A] (L/S=100/100)
Over Polish (%)
End Point Time (sec)
WIWNU (%)
Cu RR (A/min)
High Cu removal rate and good uniformity
JSR Confidential 20
Barrier Metal CMP using CMS8400/Filler Pad
1,360TaN RR (A/min)
884Ta RR (A/min)
2222Dishing [A] (120um pad)
66Scratch Counts (OM)
5656Erosion [A] (L/S=0.35/0.35)
170170Erosion [A] (L/S=4.5/0.5)
9898
60
404
Barrier Metal Polish
Dishing [A] (L/S=100/100)
Polish Time (sec)
Cu RR (A/min)
Excellent planarity and less scratches
JSR Confidential 21
ConclusionsHigh PerformanceHigh Performance SlurriesSlurries exhibit excellent Dishing/Erosion performance and high Cu removal rate.Pad surface control is the key technology for less scratches. JSR proprietary Filler Pad TechnologyFiller Pad Technology enables the soft and controlled micro-pore structured surface for less scratches while maintaining sufficient removal rate and planarity.Advanced Cu/Low-K CMP process is proposed using the combination of High PerformanceHigh Performance SlurriesSlurries with Filler Pad TechnologyFiller Pad Technology.