Photolithography

1
Photolithography
Si wafer
2
Step 1
Polymer film Solvent
Spin coating
Si wafer
3
Step 2
Solvent
Polymer film
Heat
Si wafer
4
Step 3
Place the mask on top
Polymer film
Si wafer
5
Step 4
UV light
Si wafer
6
Step 5
Remove mask
Si wafer
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Step 6
Heat
Si wafer
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Step 7
Develop and Dry
Si wafer
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Step 8
Etching
Si wafer
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How the UV light breaks the polymer
Think of the polymer film on the Si wafer as a
very tiny bowl of noodles. In the polymer film
there is another chemical called PAG and when UV
light hits it, it becomes active. Then when we
heat the polymer the PAG leaves and going up it
breaks polymer noodles. When we depelop the
wafer the small noodles dissolve while the
polymer part that wasnt hit by the UV light
doesnt.
Step 2
Step 4
Step 6
Step 7