4. contamination reduction
TRANSCRIPT
Contamination Reduction: Clean Rooms, Wafer Cleaning
and Gettering
Level 1 Contamination Reduction: Clean Factories
Class X means that in each cubic foot of air in the factory, there are less than X total particles of size greater than 0.5 µm.
Level 1 Contamination Reduction: Clean Factories
Level 2 Contamination Reduction: Wafer Cleaning
Level 2 Contamination Reduction: Wafer Cleaning
Level 2 Contamination Reduction: Wafer Cleaning
Level 2 Contamination Reduction: Wafer Cleaning
Level 3 Contamination Reduction: Gettering
Level 3 Contamination Reduction: Gettering
Level 3 Contamination Reduction: Gettering
Level 3 Contamination Reduction: Gettering
Level 3 Contamination Reduction: Gettering
• “Trap” sites can be created by SiO2 precipitates (intrinsic gettering), or by backside damage (extrinsic gettering).
• In intrinsic gettering, CZ silicon is used and SiO2 precipitates are formed in the wafer bulk through temperature cycling at the start of the process.
SiO2 precipitates (white dots) in bulk of wafer.
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
Modeling Particle Contamination and Yield
• Vertical lines are estimated chip sizes (from the ITRS).
• Note that defect densities will need to be extremely small in the future to achieve the high yields required for economic IC manufacturing.
• (See the starting slide for particle defect densities.)
Modeling Wafer Cleaning
Modeling Wafer Cleaning
Modeling Wafer Cleaning
• The strongest oxidants are at the bottom (H2O2 and O3). These reactions go to the left grabbing e- and forcing (6) to the right.
• Fundamentally RCA clean works by using H2O2 as a strong oxidant.
Modeling Gettering
Modeling Gettering
Modeling Gettering
Summary of Key Ideas
Summary of Key Ideas
