1. E-beam Lithography for Optical Gratings and Waveguides
EE412 Week 3
E-beam Lithography for Optical Gratings and Waveguides
Chia-Ming Chang
Mentor: Richard Tiberio
April 12, 2011

2. Project update Alignment marks for both ASML and e-beam lithography.
Requirement of JEOL alignment marks (from Rich):
Can we use the alignment marks from ASML mask?
1mm
1mm
1-2um
1mm
1-2um
1mm
1-2um
1-2um
>500nm
>500nm

3. Project update Alignment marks for both ASML and e-beam lithography.
ASML alignment marks library (from ASML staff). We might be able to use some of their alignment marks for JEOL; for example, PM marks.
440um
10um
1um
5um
ASML PM marks

4. Project update Mix of ASML and E-beam Works for this week
Talked to James Conway about their experience of mixing SNF Raith and ASML. We are working on the process flows, including the combination of E-beam with the GOPHER process.
Some issues include alignment marks and error (discussed above), process flow (eg. e-beam first or ASML first)
Works for this week
Finish the process flow design and alignment marks selection
Start to test different kinds of alignment marks

5. Backup

6. Test plan I: Develop a process that can combine ASML and E-beam litho
Fiber mode
Adiabatic taper
Optical waveguide
Input gratings
Output gratings
Test structure: grating couplers
Optical waveguides and adiabatic tapers are defined by ASML
Grating couplers are defined by E-beam
Methods: SEM, AFM, optical loss measurement

7. Devices ASML: Waveguide E-beam: Grating 0.7um PR 0.2um PMMA SiO2 SiO2
Silicon
SiO2
0.7um PR
ASML: Waveguide
Silicon
SiO2
0.2um PMMA
E-beam: Grating
E-beam alignment mark

8. Test plan II: Characterize surface roughness caused by ASML and E-beam
Waveguide
Surface roughness is the dominant loss mechanism of sub-micron optical waveguides
Characterize surface roughness caused by
1. ASML and photoresist
2. E-beam and photoresist
Methods: SEM, AFM, optical loss measurement

9. Equipment list Thermal Oxidation: tylan 1 and 2
LPCVD: tylanBPSG, tylannitride
Photolithography: ASML, JEOL E-beam
Etch: P5000, amtetcher, drytek2
Characterization (Nova), AFM

10. Timeline Week 1 - 2 Week 3 - 6 Week 7 and 8 Week 9 and 10
Project proposal and training
Structure and process flow design
Week 3 - 6
ASML and E-beam litho characterization
Device fabrications
Week 7 and 8
Device fabrications and testing (SEM, AFM, optical measurement)
Week 9 and 10
More testing
Presentation and report