This report documents the contrast curves for the PMMA A2 electron beam lithography resist from MicroChem. Spin curves for PMMA A2 can be found in previous work. The aim is to provide an approximate clearing and base dose for the PMMA A2 standard process at the Singh Center for Nanotechnology

Azadi, Mohsen

Lopez, Gerald G., Ph.D.

English

Kosmopolis

University of Pennsylvania
ScholarlyCommons
Protocols and Reports Browse by Type
12-16-2016
PMMA A2 Contrast Curves
Gerald G. Lopez Ph.D.
Singh Center for Nanotechnology, lopezg@seas.upenn.edu
Mohsen Azadi
Singh Center for Nanotechnology, azadi@seas.upenn.edu
Follow this and additional works at: http://repository.upenn.edu/scn_protocols
Part of the Nanoscience and Nanotechnology Commons
This paper is posted at ScholarlyCommons. http://repository.upenn.edu/scn_protocols/35
For more information, please contact repository@pobox.upenn.edu.
Lopez, Gerald G. Ph.D. and Azadi, Mohsen, "PMMA A2 Contrast Curves", Protocols and Reports. Paper 35.
http://repository.upenn.edu/scn_protocols/35
PMMA A2 Contrast Curves
Abstract
This report documents the contrast curves for the PMMA A2 electron beam lithography resist from
MicroChem. Spin curves for PMMA A2 can be found in previous work. The aim is to provide an approximate
clearing and base dose for the PMMA A2 standard process at the Singh Center for Nanotechnology.
Keywords
PMMA A2, Contrast Curves
Disciplines
Nanoscience and Nanotechnology
This technical report is available at ScholarlyCommons: http://repository.upenn.edu/scn_protocols/35
 
Standard Operating Procedure 
PMMA A2 Contrast Curves 
Revision: 20161216 
Author: Gerald Lopez, Ph.D. and 
Mohsen Azadi 
 
 
 Page 1 
Goal:  
 This report documents the contrast curves for the PMMA A2 electron beam lithography resist from 
MicroChem. Spin curves can be found in previous work and is available at 
http://repository.upenn.edu/scn_protocols/34/. The aim is to provide an approximate clearing and base dose for 
the PMMA A2 standard process at the Singh Center for Nanotechnology.  
 
Materials: 
 MicroChem PMMA A2 
 3” Si wafers 
 3 clean beakers 
 One large enough to develop a 3” 
wafer  
 Two 80mL beakers 
 Developer: DI water, Isopropyl Alcohol (IPA) 
Equipment: 
 ReynoldsTech Spinner 
 Torrey Pines Scientific Hotplate 
 Filmetrics F40  
 Elionix ELS-7500EX Electron Beam 
Lithography (EBL) Tool 
 Timer 
 
 
Protocol: 
Spin Coat and Soft Bake 
1. Mount wafer and ensure that it is centered on the ReynoldsTech Spinner 
2. Spin wafer at a fixed RPM for 60 seconds. 
3. Bake wafer at 180 °C for 90 seconds and allow wafer to cool after removal. 
 
Exposure 
1. Generate an array of 60 micron by 60 micron square in a dose matrix on a 100 micron pitch. 
2. Using the Elionix ELS-7500EX EBL tool, expose the pattern using 100pA with a 30 micron objective 
lens aperture (OLA, a.k.a. final aperture). 
 
Developer Preparation: 3:1 IPA:DI Water Co-solvent Developer 
1. Pour 60mL of DI Water into the first clean 80mL beaker. 
2. Pour 20mL of IPA into the second clean beaker. 
3. Pour the contents of the DI water into the beaker containing the IPA. Alternate pouring from one 
beaker to another to guarantee thorough mixing. 
4. When finished, pour the dilution into to larger beaker. 
 
Development at ~20°C 
1. Set timer to 60 seconds. 
2. Drop exposed wafer into bath of 3:1 IPA:DI water co-solvent developer making sure the wafer is 
completely submerged, and start the timer. Do not agitate. 
3. After 60 seconds, remove the wafer from the bath and place on a TexWipe. 
4. Blow dry the wafer with N2. 
 
Measurement 
1. Allow the Filmetrics F40 light to warm up for at least 5 minutes. 
2. Click Baseline… to calibrate the tool using the SiO2 and Si standards. 
3. Mount wafer and select the PMMA on Si recipe. 
4. Measure the resist thickness at the center of each square. 
 
 
Standard Operating Procedure 
PMMA A2 Contrast Curves 
 
Revision: 20161216 
Author: Gerald G. Lopez, Ph.D.  Page 2 
Results: 
 
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Th
ic
kn
e
ss
 [
n
m
]
Dose [µC/cm2]
Development: 60s 3:1 IPA:DI Water, 
N2 Blow Dry
125nm
102nm
89nm
78nm
72nm
68nm
65nm
60nm
57nm
55nm
54nm
 
Standard Operating Procedure 
PMMA A2 Contrast Curves 
 
Revision: 20161216 
Author: Gerald G. Lopez, Ph.D.  Page 3 
Pads were exposed to 155 µC/cm2.  
Dose 
[mC/cm2] 
Resist Thickness 
125nm 102nm 89nm 78nm 72nm 68nm 65nm 60nm 57nm 55nm 54nm 
10 122.2 100.7 87 77.6 71.8 67.5 64.1 59.8 56.6 54.9 53.5 
15 121.4 100.1 86.6 77.3 71.5 66.4 63.9 59.8 56.5 54.6 52.8 
20 120.5 98.5 85.6 77.8 71.2 65.6 62.7 58.8 56.6 54.3 52.8 
25 117.8 98.5 85.7 76.7 70.9 64.9 62.2 58 55.3 53.4 51.9 
30 116.6 97.8 84.8 76.3 70.3 63.7 61.3 57.4 54.2 52.3 51.2 
35 114.7 96.2 84.6 75.5 69.2 62.3 60.3 55.6 53.1 51.4 49.3 
40 111.3 94.5 84.2 75.2 68.3 61.8 58.9 54 52.1 49.3 46.8 
45 109.2 92.9 83.1 73.9 66.6 59.3 57 53 50.3 48 46.8 
50 106 90.8 81.5 72.7 65 57.4 55.1 50 48.1 45.4 43.9 
55 102.4 89.3 79.6 71.6 63.1 53.9 53.1 48.5 47.1 42.7 41.2 
60 98.2 86.3 78.2 69.9 61.4 51.8 51.1 45.7 44.1 39.7 38.2 
65 94.7 84.2 76.6 67.7 58.6 47.7 48.1 42.8 41.6 37.3 35.1 
70 89.8 79.5 74.2 65.4 55.6 46.2 45.7 38.8 36.9 33.3 32.1 
75 84.7 75.4 68.8 62.7 52.5 41.6 41.2 35.3 34.7 30.8 29.6 
80 79.3 70.9 65.8 59.9 48 36.8 38.6 32.3 31 25.8 26.3 
85 73 66.8 62.5 56.8 45.4 31.4 32.8 27.6 24.9 21.9 20.2 
90 66 61.8 57.6 54 40 26.7 30.7 22.3 22.3 16.4 14.6 
95 58.6 54.2 53.4 48 33.9 22.3 24.8 18.1 17.1 15.5 0 
100 47.8 48.6 48.4 44.9 28.7 14.8 20.2 13.2 13.5 13.2 0 
105 38.8 40.8 41.8 40 23.6 0 14.6 0 0 0 0 
110 27.2 31.7 35.7 34.3 15.7 0 0 0 0 0 0 
115 11.6 23.2 29.8 27.6 13.1 0 0 0 0 0 0 
120 0 0 0 0 0 0 0 0 0 0 0 
125 0 0 0 0 0 0 0 0 0 0 0 
130 0 0 0 0 0 0 0 0 0 0 0 
135 0 0 0 0 0 0 0 0 0 0 0 
140 0 0 0 0 0 0 0 0 0 0 0 
145 0 0 0 0 0 0 0 0 0 0 0 
150 0 0 0 0 0 0 0 0 0 0 0 
155 0 0 0 0 0 0 0 0 0 0 0 
 
 
  
 


PMMA A2 Contrast Curves

ScholarlyCommons@Penn

University of PennsylvaniaScholarlyCommonsProtocols and Reports Browse by Type12-16-2016PMMA A2 Contrast CurvesGerald G. Lopez Ph.D.Singh Center for Nanotechnology, lopezg@seas.upenn.eduMohsen AzadiSingh Center for Nanotechnology, azadi@seas.upenn.eduFollow this and additional works at: http://repository.upenn.edu/scn_protocolsPart of the Nanoscience and Nanotechnology CommonsThis paper is posted at ScholarlyCommons. http://repository.upenn.edu/scn_protocols/35For more information, please contact repository@pobox.upenn.edu.Lopez, Gerald G. Ph.D. and Azadi, Mohsen, "PMMA A2 Contrast Curves", Protocols and Reports. Paper 35.http://repository.upenn.edu/scn_protocols/35PMMA A2 Contrast CurvesAbstractThis report documents the contrast curves for the PMMA A2 electron beam lithography resist fromMicroChem. Spin curves for PMMA A2 can be found in previous work. The aim is to provide an approximateclearing and base dose for the PMMA A2 standard process at the Singh Center for Nanotechnology.KeywordsPMMA A2, Contrast CurvesDisciplinesNanoscience and NanotechnologyThis technical report is available at ScholarlyCommons: http://repository.upenn.edu/scn_protocols/35 Standard Operating Procedure PMMA A2 Contrast Curves Revision: 20161216 Author: Gerald Lopez, Ph.D. and Mohsen Azadi    Page 1 Goal:   This report documents the contrast curves for the PMMA A2 electron beam lithography resist from MicroChem. Spin curves can be found in previous work and is available at http://repository.upenn.edu/scn_protocols/34/. The aim is to provide an approximate clearing and base dose for the PMMA A2 standard process at the Singh Center for Nanotechnology.   Materials:  MicroChem PMMA A2  3” Si wafers  3 clean beakers  One large enough to develop a 3” wafer   Two 80mL beakers  Developer: DI water, Isopropyl Alcohol (IPA) Equipment:  ReynoldsTech Spinner  Torrey Pines Scientific Hotplate  Filmetrics F40   Elionix ELS-7500EX Electron Beam Lithography (EBL) Tool  Timer   Protocol: Spin Coat and Soft Bake 1. Mount wafer and ensure that it is centered on the ReynoldsTech Spinner 2. Spin wafer at a fixed RPM for 60 seconds. 3. Bake wafer at 180 °C for 90 seconds and allow wafer to cool after removal.  Exposure 1. Generate an array of 60 micron by 60 micron square in a dose matrix on a 100 micron pitch. 2. Using the Elionix ELS-7500EX EBL tool, expose the pattern using 100pA with a 30 micron objective lens aperture (OLA, a.k.a. final aperture).  Developer Preparation: 3:1 IPA:DI Water Co-solvent Developer 1. Pour 60mL of DI Water into the first clean 80mL beaker. 2. Pour 20mL of IPA into the second clean beaker. 3. Pour the contents of the DI water into the beaker containing the IPA. Alternate pouring from one beaker to another to guarantee thorough mixing. 4. When finished, pour the dilution into to larger beaker.  Development at ~20°C 1. Set timer to 60 seconds. 2. Drop exposed wafer into bath of 3:1 IPA:DI water co-solvent developer making sure the wafer is completely submerged, and start the timer. Do not agitate. 3. After 60 seconds, remove the wafer from the bath and place on a TexWipe. 4. Blow dry the wafer with N2.  Measurement 1. Allow the Filmetrics F40 light to warm up for at least 5 minutes. 2. Click Baseline… to calibrate the tool using the SiO2 and Si standards. 3. Mount wafer and select the PMMA on Si recipe. 4. Measure the resist thickness at the center of each square.   Standard Operating Procedure PMMA A2 Contrast Curves  Revision: 20161216 Author: Gerald G. Lopez, Ph.D.  Page 2 Results:  051015202530354045505560657075808590951001051101151201251300 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150Thickness [nm]Dose [µC/cm2]Development: 60s 3:1 IPA:DI Water, N2 Blow Dry125nm102nm89nm78nm72nm68nm65nm60nm57nm55nm54nm Standard Operating Procedure PMMA A2 Contrast Curves  Revision: 20161216 Author: Gerald G. Lopez, Ph.D.  Page 3 Pads were exposed to 155 µC/cm2.  Dose [mC/cm2] Resist Thickness 125nm 102nm 89nm 78nm 72nm 68nm 65nm 60nm 57nm 55nm 54nm 10 122.2 100.7 87 77.6 71.8 67.5 64.1 59.8 56.6 54.9 53.5 15 121.4 100.1 86.6 77.3 71.5 66.4 63.9 59.8 56.5 54.6 52.8 20 120.5 98.5 85.6 77.8 71.2 65.6 62.7 58.8 56.6 54.3 52.8 25 117.8 98.5 85.7 76.7 70.9 64.9 62.2 58 55.3 53.4 51.9 30 116.6 97.8 84.8 76.3 70.3 63.7 61.3 57.4 54.2 52.3 51.2 35 114.7 96.2 84.6 75.5 69.2 62.3 60.3 55.6 53.1 51.4 49.3 40 111.3 94.5 84.2 75.2 68.3 61.8 58.9 54 52.1 49.3 46.8 45 109.2 92.9 83.1 73.9 66.6 59.3 57 53 50.3 48 46.8 50 106 90.8 81.5 72.7 65 57.4 55.1 50 48.1 45.4 43.9 55 102.4 89.3 79.6 71.6 63.1 53.9 53.1 48.5 47.1 42.7 41.2 60 98.2 86.3 78.2 69.9 61.4 51.8 51.1 45.7 44.1 39.7 38.2 65 94.7 84.2 76.6 67.7 58.6 47.7 48.1 42.8 41.6 37.3 35.1 70 89.8 79.5 74.2 65.4 55.6 46.2 45.7 38.8 36.9 33.3 32.1 75 84.7 75.4 68.8 62.7 52.5 41.6 41.2 35.3 34.7 30.8 29.6 80 79.3 70.9 65.8 59.9 48 36.8 38.6 32.3 31 25.8 26.3 85 73 66.8 62.5 56.8 45.4 31.4 32.8 27.6 24.9 21.9 20.2 90 66 61.8 57.6 54 40 26.7 30.7 22.3 22.3 16.4 14.6 95 58.6 54.2 53.4 48 33.9 22.3 24.8 18.1 17.1 15.5 0 100 47.8 48.6 48.4 44.9 28.7 14.8 20.2 13.2 13.5 13.2 0 105 38.8 40.8 41.8 40 23.6 0 14.6 0 0 0 0 110 27.2 31.7 35.7 34.3 15.7 0 0 0 0 0 0 115 11.6 23.2 29.8 27.6 13.1 0 0 0 0 0 0 120 0 0 0 0 0 0 0 0 0 0 0 125 0 0 0 0 0 0 0 0 0 0 0 130 0 0 0 0 0 0 0 0 0 0 0 135 0 0 0 0 0 0 0 0 0 0 0 140 0 0 0 0 0 0 0 0 0 0 0 145 0 0 0 0 0 0 0 0 0 0 0 150 0 0 0 0 0 0 0 0 0 0 0 155 0 0 0 0 0 0 0 0 0 0 0      

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PMMA A2 Contrast Curves

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