weir pw analysis of wafer-chuck influence on features dataset:80_d2_1_2 features: device: 8-25 6x5...
TRANSCRIPT
Weir PWWeir PWWeir PWWeir PW
Analysis of wafer-chuck influence on features
Dataset: 80_D2_1_2
Features: Device: 8-25 6x5 1:1 / Level: ASML AMD 100 1-2 T 320-640nmLotName No:80D2_1_2 03-Nov-03
TEA Systems Corp.65 Schlossburg St.Alburtis, PA 18011
610 682 [email protected]
November 12, 2003
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -2-TEA Systems Corp. Confidential
Investigation• Each wafer chuck provides
kinematic support for the wafer on 3 pins Located at an approximate
radius of 30 mm from wafer center
Separated by 60degrees Pin is 2 mm in diameter
• Wafer is then suspended above the chuck by approximately 75 um.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -3-TEA Systems Corp. Confidential
Raw data measured
• Scatter tool data used: Nanometrics
• Weir PW analysis
• Data included: BCD TCD SWA T3 (Resist) T2 (BARC)
• Die Size is (25,28)mm
T2 (nm) T3 (nm) MSE BCD (nm) SWA (°) TCD (nm) Z(µm)Count 1099 1105 1110 1094 1110 1078 1110Mean 72.83577798 213.7036 84.339436 93.80762 86.10995 72.67932 -181.5712
Median 38.915 261.73 3498.6597 100 55.216 40.215 -194.4SEM 0.07762979 0.419608 21.710465 0.308246 0.192121 0.157673 0.227958
Maximum 77.83 350 6997.1172 200 87.448 80.43 -127.1Minimum 0 173.46 0.2021 0 22.984 0 -261.7
Range 77.83 176.54 6996.9151 200 64.464 80.43 134.6MinMax 77.83 350 6997.1172 200 87.448 80.43 -261.7
Variance 6.622996366 194.5581 523192.18 103.9468 40.97071 26.79985 57.68076StDev 2.573518286 13.94841 723.32024 10.19543 6.400837 5.176857 7.594785
Mean+3Sigma 80.55633284 255.5488 2254.3002 124.3939 105.3125 88.20989 -204.3555
Locations on Field
Locations on Wafer
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -4-TEA Systems Corp. Confidential
Wafer Modeled BARC
• Wafer systematic errors have been removed.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -5-TEA Systems Corp. Confidential
BARC: Wafer cross-section
• Examination of cross-section as shown
• Notice definite step at wafer 30 mm diameter
Potential pad site
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -6-TEA Systems Corp. Confidential
BARC radial
• Step occurs outside of pin radius = 30 mm.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -7-TEA Systems Corp. Confidential
Photoresist
• Wafer-systematic errors have been removed Mean value of 211.8 nm also
removed
• Three points may show as slightly shifted contacts. Note circled points
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -8-TEA Systems Corp. Confidential
BCD – Wafer & Average field removed
• Plotting Bottom CD after removal of: Wafer aberrations Average field.
3 potential locations of wafer pads
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -9-TEA Systems Corp. Confidential
Top CD variation after mean field is removed
• Examine the CD variation after having remove: Wafer systematic errors and The average field.(reticle)
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -10-TEA Systems Corp. Confidential
Top CDs and radius
• Notice “dip” located at the 30 mm radius
• From here on we will restrict the analysis radius to 94 mm Excludes the bad data points shown at the edge-bead.
TCD (nm) vs field radius
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
4.00
5.00
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Radius
To
p C
D
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -11-TEA Systems Corp. Confidential
Conclusion & discussion points
• BARC, Photoresist and Bottom CD’s suggest there is an effect occurring at the 30 mm wafer radius. Bottom CD and photoresist strongly suggest the presence of 3 sites at the radius and spacing
suggested by the wafer-chuck pins. BARC has a radial height variation that also suggests something strong happening below this
30 mm radius.
• Top CD shows some reaction but it is not as apparent as with the previous variables discussed.
• SWA does not show the effect
TEA Systems Corp. Confidential
Analysis Slides presented as backup data
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -13-TEA Systems Corp. Confidential
Raw BARC Thickness (T2)
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -14-TEA Systems Corp. Confidential
Wafer Modeled BARC
• Wafer systematic errors have been removed.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -15-TEA Systems Corp. Confidential
BARC: Wafer cross-section
• Examination of cross-section as shown
• Notice definite step at wafer 30 mm diameter
Potential pad site
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -16-TEA Systems Corp. Confidential
BARC radial
• Step occurs outside of pin radius = 30 mm.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -17-TEA Systems Corp. Confidential
Weir PWMeasurement of Bottom
Raw – Bottom CDs
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -18-TEA Systems Corp. Confidential
Wafer Modeled Bottom - CD
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -19-TEA Systems Corp. Confidential
Histogram after wafer aberrations are removed
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -20-TEA Systems Corp. Confidential
BCD – Wafer errors removed
• Data removed: Wafer systematic Mean Bottom CD
offset = 94.09 nm
• Display is dominated by the signature of the reticle.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -21-TEA Systems Corp. Confidential
BCD – Wafer & Average field removed
• Plotting Bottom CD after removal of: Wafer aberrations Average field.
3 potential locations of wafer pads
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -22-TEA Systems Corp. Confidential
Top CD; Wafer Model
• Offset is not plotted
• We’ll now remove these systematic errors.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -23-TEA Systems Corp. Confidential
Top CD variation after mean field is removed
• Examine the CD variation after having remove: Wafer systematic errors and The average field.(reticle)
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -24-TEA Systems Corp. Confidential
Top CDs and radius
• Notice “dip” located at the 30 mm radius
• From here on we will restrict the analysis radius to 94 mm Excludes the bad data points shown at the edge-bead.
TCD (nm) vs field radius
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
4.00
5.00
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Radius
To
p C
D
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -25-TEA Systems Corp. Confidential
SWA Wafer Model
• SWA variation across systematic error model
• Offset of 86.1 deg. Is not included.
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -26-TEA Systems Corp. Confidential
SWA residuals
• Removed Wafer model Average Field
• Each site is averaged & then removed.
• SWA exhibits only the variation caused by the start and top of the exposure scan.
• Does not show any reaction at 30 mm radius
November 2003 Weir PW - Wafer Chuck Influence on CDs Page -27-TEA Systems Corp. Confidential
Photoresist
• Wafer-systematic errors have been removed Mean value of 211.8 nm also
removed
• Three points may show as slightly shifted contacts. Note circled points