nccavs plasma applications group meetingtemperature profile during poly etch 11/23/2011 confidential...
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NCCAVS Plasma Applications Group MeetingNCCAVS Plasma Applications Group Meeting
EtchTemp Silicon Etch (ET-SE)
Giampietro Bieli: Application Manager
SensArray Division
Executive Summary
� EtchTemp Silicon Etch (ET-SE) targets Poly/STI Etch application
� ET-SE hasY2O3 deposited on top of the Si cover of EtchTemp
� Metal contamination levels are similar to regular EtchTemp (silicon cover)
� Prototype testing in Poly Etch (HBr Chemistry)
� Etch rate of Y2O3 film is minimal to none
� Temperature profile during Poly Etch
11/23/2011 confidential
� Temperature profile during Poly Etch
� Delta temperature between ET-SE Prototype and ET
� No Significant Delta Temp between ET-SE and standard ET
� Temperature profile in continuous Plasma ON condition
� ET-SE shows stable temperature up to 10mins Plasma On
� Prototype testing in Poly Etch (SF6 Chemistry)
� Etch rate of Y2O3 film is minimal to none
EtchTemp-SEPlasma ON Temperature Monitoring of Silicon Etch Processes
� Flat, wireless wafer for in-situ silicon etch
chamber & process temperature monitoring
� Enhancements over silicon etch alternatives
(special coating, wider operating range,
improved S:N, greater lifetime, & lower profile)
� Temperature monitoring with silicon etch
chemistry & plasma ON in key use cases:
Accuracy: +/- 0.2C, Precision: 0.25C, Range: 15-130C
Si top cover
Y2O3 coating
65 sensors,
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EtchTemp-SE
chemistry & plasma ON in key use cases:
� Qualify new etch chambers
� Match etch chambers
� Post-PM chamber verification
� Electrostatic chuck qualification
Enabling Plasma ON Wafer Temperature Monitoring of Silicon Etch Process
Si substrate
65 sensors,
electronics,
shielding,
battery
Use case: Plasma ON details
Accuracy: +/- 0.2C, Precision: 0.25C, Range: 15-130C
Si top cover
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Plasma ON Differences ET VS
ET-SE
Si substrate
65 sensors,
electronics,
shielding,
battery
EtchTemp
Key Spec Comparison
EtchTemp vs. EtchTemp-SE
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No Significant Delta Temp Between ET-SE (Y2O3) and Std. ET Poly Etch
59.73 59.7759.75
63.43 63.71
63.53
57
58
59
60
61
62
63
64
65
Std Silicon cover Vs Y2O3 cover
MEAN
Plasma OFF Mean Plasma ON Mean
Std Silicon cover Vs Y2O3 cover
11/23/2011
Etchtemp with standard silicon cover vs Etchtemp with Yttrium coating
Test to verify that Y2O3 will not affect temperature reading
57
Std ET 1 Std ET 2 Y203
1.67 1.68 1.5
3.8
2.73.5
0
0.5
1
1.5
2
2.5
3
3.5
4
Std ET 1 Std ET 2 Y203
Std Silicon cover Vs Y2O3 cover
RANGE
Plasma OFF Plasma ON
EtchTemp Silicon Etch (ET-SE) ValueDeep Trench Etch
1.5
2
2.5
3
T
E
M
P
D
Center of the wafer show
significant temperature
delta if Proxy recipe is
used
Proxy recipe doesn't to
provide the real
temperature response
2011/11/23 confidential
0
0.5
1
1.5
CENTER EDGE
D
E
L
T
A
Temperature delta using Production recipe (HBr/NF3/O2) and Proxy Recipe
(Ar/O2)
temperature response
Use Case
Chamber A Chamber B
ET-SE
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
1.02
1.04
15.3
15.8
16.3
16.8
17.3
17.8
CENTER EDGE
T
E
M
P
E
R
A
T
U
R
E
Temp Data
Etch Depth
ET-SE identify edge temperature issue correlated to etch depth issue
DTI Logic
CH A
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EtchDepth
Temperature data correlate to Etch Rate data
Higher Etch Rate= Higher Temperature
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
1.02
1.04
15.3
15.8
16.3
16.8
17.3
17.8
CENTER EDGE
T
E
M
P
E
R
A
T
U
R
E Temp Data
Etch Depth
CH B
CH BCH BCH ACH A--DOWNDOWN
Full wafer Full wafer Full wafer Full wafer
ET-SE identified Yield issue : CH A production Hold for CDU issues STI Etch
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CH BCH BCH ACH A--DOWNDOWN
Full wafer Mean DELTA:3.98 degree
Edge onlyEdge onlyEdge onlyEdge only
YIELD ISSUE AT THE EDGE SOLVED WITH ESC REPLACEMENT
CH ACH A--DOWNDOWN
CH ACH A--DOWNDOWN
CH BCH B
CH BCH B
High CD Chamber shows High Wafer Temperature
STI Etch
Tool X
Tool Y
CH A CH B
CH C CH D
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Tool Z
CH E CH F
CH A CH B CH C CH D CH E CH F
ET-SE shows CH D has an outlier , this
correlate to High CD
Golden Chamber
Pre PM bad chamber
Post PM bad chamber
High CD Chamber shows High Wafer Temperature
STI Etch
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Post ESC replacement fixed the edge temperature spread with
between golden ch and down ch
Golden
Chambers
Pre PM Bad
Chambers
Post PM Bad
Chambers
ESC has many hours
ET-SE identify ESC lifetime impact on TemperaturePoly Etch
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Example of ESC plasma ON data collection that was able to identify
chamber differences due to ESC lifetime
Golden Chamber ESC has low hours
Chamber fleet
ET-SEPoly Etch
�Chamber matching
issue within different
fabs.
�Also, demonstrated
process gas trouble
shooting capability with
ET-SE.
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Golden ChamberChamber ADown Chamber
ET-SE.
�This excursion event
led to a 3-week
chamber down time
before temperature
analysis.
Analysis of Edge Sensors Only
Inner
Outer zone
Mid Inner
Mid outer
CH1 CH2
ET-SE Recommended for 4zone ESC Plasma ON Qualification
Poly Etch
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Inner
CH
1 Temperature analysis by ESC zone in order to
study CD/Yield localized issueCH1 CH2
CH1 CH2
CH1 CH2
PM1PM6
ET-SE Identifies Hot Spot that Correlates to CD Excursion
Poly Mask Etch
74
76
78
80
82
PM1
PM2
PM6
CD Excursion
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PM2
66
68
70
72
74
0 50 100 150 200
PM6
Poly. (PM1)
Log. (PM2)
Poly. (PM6)
PM2 shows CD excursion in lower left edge that correlates to hot spot seen on
ET-SE
High
temperature
area correlate
with CD
excursion
Radial Plot
Temperature Variation across Chambers & Shifts Over Time
Cylinder Support Etch
Old Method: 12hours
Etch Test
Wafer
Measure
CD
Post Etch
Process Test
Wafer
Defect
Inspection
ET-SEPM
Temp
OK?
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Chamber baseline confirmed shifts over time
New Procedure: Post PM temperature data collection for chamber monitor and faster
troubleshooting
ET-SE Method: 30mins
OK?
Conclusion
� ET-SE demonstrated temperature monitoring capability with silicon etch
chemistry & plasma ON in key use cases
� ET-SE is used for :
� Chamber Matching
� Troubleshooting
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� Chamber Monitoring
� Temperature DOE for process optimization
� ESC replacement
� Tool Start up
� Post Pm chamber verification
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