Hong Kong University of Science & Technology
Department of Electrical & Electronic Engineering
Spring 2006
ELEC 300Q: Integrated Circuit Fabrication Technology
Lab 10: May 3rd , 2006
Step 26: Aluminium Deposition
26.1: HF Dip
Composition of H2O:HF = __________________
Temperature: ________________________
Total etch time: ______________________
DI water rinse:
Number of Cycles = ____________
Time = _____________
Spin Rinse/Dry:
Rinse RPM = ____________
Rinse Time (seconds) = _____________
Remark: _____________________________________________________________
26.2: Oven-bake Dehydration
Oven temperature: _________________
Bake time: ________________________
26.2: Aluminium Sputtering: Target = 6000nm
Machine used: ______________________
Expected Deposition Rate: ______________________
Calibrated Deposition Rate: _____________________
Deposition Time: _______________________
Aluminium Thickness: ______________________
Remark: _____________________________________________________________
Step 27: Aluminium Deposition
27.0: Modified clean (only DI water rinse and spin dry)
Performed? Yes/No _____________________
Oven dehydration?: Duration = __________________________
27.1 Photoresist Coating by SVG Track
Program name = _______________________
Resist type = ____________
Spin RPM = _______________
Spin time (seconds) = _______________
Resist thickness (m) = ________________
Pre-bake Temperature (oC) = _____________
Pre-bake Time (seconds) = ______________
27.2 Photoresist exposure (20% reduction in exposure time):
Aligner = _________________________
Mask = _________________
Align to = ________________________
Contact mode = _______________________
Contact pressure (Torr) = _________________________
Exposure dose (mJ/cm2) = ___________________________
Time (s): ___________________________
Underexposure? (%) _________________________________
27.2 Photoresist Development by SVG Track:
Developer type = __________________
Soak time (seconds) = _______________________
Rinse RPM = _____________________
Rinse time (seconds) = _____________________
Dry RPM = ________________________________
Spin time (seconds) = ______________________
Post-bake Temperature (oC) = ________________________
Post-bake Time (seconds) = ________________________
27.4 Inspection:
- Misalignment check (with diagram):
Estimated x-direction misalignment: __________________
Estimated y-direction misalignment: _____________________
-
Line uniformity check and observation: ____________________________________
-
Linewidth lost check and observation: ____________________________________
-
Opening area line width check: ________________________________________
-
Corner rounding check: _____________________________________________
-
Cross-section inspection: ___________________________________________
-
Exposure condition (over-exposed/under-exposed): ______________________
Remarks: ________________________________________________________
27.5 Further post-bake in Oven:
Temperature = __________________
Time = _________________________
27.6 Descum
Oxygen flow rate = __________________
Power = _________________________
Time = __________________________
Step 28: Aluminium Etching
28.1 Method: (Plasma/Wet): _______________________
Etchant: ______________________
Temperature: ____________________
Expected etch rate: ________________________
Expected selectivity with SiO2: ________________________
Total etch time: ________________
Over-etch: ______________________
End-point detection method: ___________________________
Remarks: _____________________________________________________________
28.2 Al etch monitoring
Wafer used: ______________________________
Complete Al removal checking method and result: _______________________________
________________________________________________________________________
28.3 Photo resist removal by
Method: ____________________________
Temperature: __________________________
Time: ________________________________
Inspection result: ___________________________________
28.4 Functionality checking:
Broken line checking and result: _______________________________________________
Resistivity measurement result: _______________________________________________
Basic transistor measurement result: ____________________________________________
Report to be submitted:
(1) Fill in data for standard cleaning in the lab description for those that are relevant
(2) Sketch the cross-section of the entire wafer after step 27.6. Make sure your drawing shows the important
features of the structure
(3) Answer the following questions:
Step 26:
1) How do measure the thickness of the Aluminium you deposited?
Step 27:
2) Which layer the metal mask should be aligned to? Give reasons (and tradeoffs).
Step 27:
3) What problem it may cause if some Al still remains on the wafer? How do you make sure all the Al is removed?
Design Problem:
Design a process, using drawings and steps to create the structure given below. You just need to describe the
method like I did in the lecture and don’t need to describe the detail condition. For example, in thin-film
deposition, you can just mention depositing 100nm of a certain film without giving specific temperature and
time. But you need to specify the physical dimension (e.g. film thickness). In the figure below, the n+ region
has a thickness of 200nm, n- region has a thickness of 500nm and the oxide (top layer) has a thickness of
100nm. You have to draw both cross-section and the corresponding mask for it.
n-
p
p-
n+