Jump to content

Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 01 processing: Difference between revisions

← Older editNewer edit →
VisualWikitext
Taran (talk | contribs)
DCH-Employees-701, NLAB-Employees-701, NLAB-LabmanagerAllUsers, NLAB-Nlab307-labadviser-users-34891
3,602 edits
Taran (talk | contribs)
DCH-Employees-701, NLAB-Employees-701, NLAB-LabmanagerAllUsers, NLAB-Nlab307-labadviser-users-34891
3,602 edits
Line 195: Line 195:
| -
| -
|rowspan="2" align="center"| -
|rowspan="2" align="center"| -
| 0,04
| 0.04
| ±0,05
| ±0.05


|-
|-
Line 202: Line 202:
|'''Y'''
|'''Y'''
| -
| -
| -0,22
| -0.22
| ±0,075
| ±0.075


|-
|-
Line 220: Line 220:
|-style="background:WhiteSmoke; color:black"
|-style="background:WhiteSmoke; color:black"
|'''Y'''
|'''Y'''
| 0.999960
| <span style="color:red">0.999960</span>
| -0.31
| -0.31
| <span style="color:red">±1.30</span>
| <span style="color:red">±1.30</span>
Line 252: Line 252:
| -
| -
|rowspan="2" align="center"| -
|rowspan="2" align="center"| -
| 0,11
| 0.11
| ±0,275
| ±0.275


|-
|-
Line 259: Line 259:
|'''Y'''
|'''Y'''
| -
| -
| <span style="color:red">-2,69</span>
| <span style="color:red">-2.69</span>
| ±0,2
| ±0.2


|-
|-
Line 271: Line 271:
| -
| -
|rowspan="2" align="center"| -
|rowspan="2" align="center"| -
| 0,08
| 0.08
| ±0,1
| ±0.1


|-
|-
Line 278: Line 278:
|'''Y'''
|'''Y'''
| -
| -
| <span style="color:red">-2,16</span>
| <span style="color:red">-2.16</span>
| ±0,15
| ±0.15


|-
|-
Line 290: Line 290:
| -
| -
|rowspan="2" align="center"| -
|rowspan="2" align="center"| -
| -0,26
| -0.26
| ±0,25
| ±0.25


|-
|-
Line 297: Line 297:
|'''Y'''
|'''Y'''
| -
| -
| -0,01
| -0.01
| ±0,15
| ±0.15


|-
|-
Line 309: Line 309:
| -
| -
|rowspan="2" align="center"| -
|rowspan="2" align="center"| -
| 0,02
| 0.02
| ±0,1
| ±0.1


|-
|-
Line 316: Line 316:
|'''Y'''
|'''Y'''
| -
| -
| 0,02
| 0.02
| ±0,2
| ±0.2


|-
|-
Line 334: Line 334:
|-style="background:WhiteSmoke; color:black"
|-style="background:WhiteSmoke; color:black"
|'''Y'''
|'''Y'''
| 0.999963
| <span style="color:red">0.999963</span>
| -1.11
| -1.11
| <span style="color:red">±1.175</span>
| <span style="color:red">±1.175</span>
|-
|-style="background:WhiteSmoke; color:black"
|rowspan="2"|3 alignment marks
(bottom half of wafer)
|'''X'''
|rowspan="2" align="center"|1: -30000; 0<br>2: 30000; 0<br>3: 0; -30000
|rowspan="2" align="center"|0.006
| 1.000003
|rowspan="2" align="center"| -0.003
| -0.11
| ±0.225
|-
|-style="background:WhiteSmoke; color:black"
|'''Y'''
| 0.999997
| 0.13
| ±0.275


|}
|}
Line 344: Line 363:
<br>The alignment test with 4 alignment marks mimics the shift from the field alignment test, but the deviation on the Y-axis is very large, probably due to the surprising -40ppm scaling measured by the alignment routine. Keep in mind that the wafer has not been unloaded between the two exposures. Something is going on with the Y-axis.
<br>The alignment test with 4 alignment marks mimics the shift from the field alignment test, but the deviation on the Y-axis is very large, probably due to the surprising -40ppm scaling measured by the alignment routine. Keep in mind that the wafer has not been unloaded between the two exposures. Something is going on with the Y-axis.
<br>Aligning with 2 marks on the X-axis seems to fix this problem, and shows an average error similar to the camera offset, with a tight distribution across the wafer. However, aligning using 2 marks on the Y-axis introduces a large shift in Y. This shift is repeated if 2 alignment marks along the X-axis on the top half of the wafer is used, but it is fixed if 2 marks along the X-axis on the bottom half are used, or if 2 marks on the Y-axis is used with the first mark on the bottom half of the wafer. Again, there seems to be something strange going on with the Y-axis.  
<br>Aligning with 2 marks on the X-axis seems to fix this problem, and shows an average error similar to the camera offset, with a tight distribution across the wafer. However, aligning using 2 marks on the Y-axis introduces a large shift in Y. This shift is repeated if 2 alignment marks along the X-axis on the top half of the wafer is used, but it is fixed if 2 marks along the X-axis on the bottom half are used, or if 2 marks on the Y-axis is used with the first mark on the bottom half of the wafer. Again, there seems to be something strange going on with the Y-axis.  
<br>In an attempt to fix the large deviation on the Y-axis when using 4 alignment marks, a test was made adding an alignment mark in 0;0 as the first mark during alignment. This did not have any beneficial effect, as the deviation on the Y-axis values is similar to the deviation from the 4 mark test.  
<br>In an attempt to fix the large deviation on the Y-axis when using 4 alignment marks, a test was made adding an alignment mark in 0;0 as the first mark during alignment. This did not have any beneficial effect, as the deviation on the Y-axis values is similar to the deviation from the 4 mark test. Finally, inspired by the success of using two alignment marks on the bottom half of the wafer, a test using 3 alignment marks on the bottom half of the wafer was done. This also seems to fix the problem, showing no scaling of the Y-axis and yielding small shifts with reasonable deviation.




Line 419: Line 438:
| -0.94
| -0.94
| <span style="color:red">±1.5</span>
| <span style="color:red">±1.5</span>
|-
|-style="background:WhiteSmoke; color:black"
|rowspan="2"|3 alignment marks
(bottom half of old QC wafer)
|'''X'''
|rowspan="2" align="center"|1: -30000; 0<br>2: 30000; 0<br>3: 0; -30000
|rowspan="2" align="center"|19.406
| 1.000032
|rowspan="2" align="center"|-0.104
| -0.22
| ±0.5
|-
|-style="background:WhiteSmoke; color:black"
|'''Y'''
| 0.999981
| -1.11
| <span style="color:red">±1.125</span>


|-
|-
Line 443: Line 481:
The alignment test with 4 alignment marks shows a +40ppm scaling on the X-axis, as well as a 0.1mRad shearing of the axes. The result is a decent alignment in X, but a shift in Y as well as a relatively large deviation. The raw data shows the deviation in Y is due to a -40ppm scaling along the Y-axis, as seen in the MLA1-MLA1 test with 4 marks, suggesting that the scaling in Y is consistently overestimated.  
The alignment test with 4 alignment marks shows a +40ppm scaling on the X-axis, as well as a 0.1mRad shearing of the axes. The result is a decent alignment in X, but a shift in Y as well as a relatively large deviation. The raw data shows the deviation in Y is due to a -40ppm scaling along the Y-axis, as seen in the MLA1-MLA1 test with 4 marks, suggesting that the scaling in Y is consistently overestimated.  
<br>Aligning using only 2 marks yields acceptable shifts in the center of the wafer, but very large shifts in X towards the edges, as evidenced by the 7.4µm deviation in X. The raw data suggests that this deviation is mainly due to a 0.2mRad tilt in the Y-axis, which corresponds well with the 0.1mRad shearing measured using 4 marks. There is also a (-)40ppm scaling along the X-axis, again similar to what was measured during 4 mark alignment. Even a 5mm chip would be affected by the 0.2mRad tilt, so clearly 4 mark alignment is needed when aligning to a pattern that was not exposed using MLA1.
<br>Aligning using only 2 marks yields acceptable shifts in the center of the wafer, but very large shifts in X towards the edges, as evidenced by the 7.4µm deviation in X. The raw data suggests that this deviation is mainly due to a 0.2mRad tilt in the Y-axis, which corresponds well with the 0.1mRad shearing measured using 4 marks. There is also a (-)40ppm scaling along the X-axis, again similar to what was measured during 4 mark alignment. Even a 5mm chip would be affected by the 0.2mRad tilt, so clearly 4 mark alignment is needed when aligning to a pattern that was not exposed using MLA1.
<br>Attempting to fix the shift in Y when using 4 alignment marks by adding 0;0 as the first mark unfortunately makes no difference. However, when MLA3 is used to align to a pattern printed using MLA1, the resulting spread of alignment errors is quite small, suggesting that MAL3 is somehow better at compensating for the differences between the two machines than MLA1.
<br>Attempting to fix the shift in Y when using 4 alignment marks by adding 0;0 as the first mark makes no difference. And the success from the MLA1-MLA1 test when using 3 marks on the bottom half of the wafer is unfortunately not repeated for MLA3-MLA1 alignment. However, when MLA3 is used to align to a pattern printed using MLA1, the resulting spread of alignment errors is quite small, showing that MAL3 is better at compensating for the differences between the two machines than MLA1, and suggesting that the problem stems only from MLA1.


=Optimal use of the maskless aligner=
=Optimal use of the maskless aligner=
Retrieved from "https://labadviser.nanolab.dtu.dk//index.php?title=Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_01_processing"