ЭБНЭ_full
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LOCOS –step 2 |
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FormActiveRegions |
ACTIVE mask |
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• Deposit SiN over wafer |
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Deposit photoresist over |
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SiN layer |
n-well |
SiN |
photoresist |
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Pattern photoresist |
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– *ACTIVE MASK |
p-type substrate |
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ACTIVE mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 22 |
LOCOS –step 2
FormActiveRegions
•Deposit SiN over wafer
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Deposit photoresist over |
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SiN layer |
n-well |
SiN |
photoresist |
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Pattern photoresist |
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– *ACTIVE MASK |
p-type substrate |
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•Etch SiN in exposed areas
–leavesSiN mask which blocks oxide growth
ACTIVE mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 23 |
LOCOS –step 2
FormActiveRegions
•Deposit SiN over wafer
•Deposit photoresist over SiN layer
•Pattern photoresist
–*ACTIVE MASK
•Etch SiN in exposed areas
–leavesSiN mask which blocks oxide growth
•Remove photoresist
•Grow Field Oxide (FOX)
–thermal oxidation
n-well
FOX
p-type substrate
ACTIVE mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 24 |
LOCOS –step 2
FormActiveRegions
•Deposit SiN over wafer
•Deposit photoresist over SiN layer
•Pattern photoresist
–*ACTIVE MASK
•Etch SiN in exposed areas
–leavesSiN mask which blocks oxide growth
•Remove photoresist
•Grow Field Oxide (FOX)
–thermal oxidation
•Remove SiN
n-well
FOX
p-type substrate
ACTIVE mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 25 |
LOCOS –step 3
FormGate (Polylayer)
•Grow thin Gate Oxide
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over entire wafer |
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negligibleeffect on FOX |
gate oxide |
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regions |
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LOCOS FabricationIllustration |
Prof.A. Mason |
Page 26 |
LOCOS –step 3
FormGate (Polylayer)
•Grow thin Gate Oxide
POLY mask
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over entire wafer |
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negligibleeffect on FOX |
gate oxide |
polysilicon |
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regions |
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•Deposit Polysilicon
•Deposit Photoresist
POLY mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 27 |
LOCOS –step 3
FormGate (Polylayer)
•Grow thin Gate Oxide
POLY mask
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over entire wafer |
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– |
negligibleeffect on FOX |
gate oxide |
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regions |
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•Deposit Polysilicon
•Deposit Photoresist
•Pattern Photoresist
–*POLY MASK
•Etch Poly in exposed areas
•Etch/remove Oxide
–gate protected by poly
POLY mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 28 |
LOCOS –step 3
FormGate (Polylayer)
•Grow thin Gate Oxide
– |
over entire wafer |
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– |
negligibleeffect on FOX |
gate oxide |
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regions |
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•Deposit Polysilicon
•Deposit Photoresist
•Pattern Photoresist
–*POLY MASK
•Etch Poly in exposed areas
•Etch/remove Oxide
–gate protected by poly
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 29 |
LOCOS –step 4
Formpmos S/D
•Cover with photoresist
PSELECT mask
PSELECT mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 30 |
LOCOS –step 4
Formpmos S/D
•Cover with photoresist
•Pattern photoresist
PSELECT mask
– *PSELECT MASK
POLY mask
LOCOS FabricationIllustration |
Prof.A. Mason |
Page 31 |