Wa fe r F a b ric a tio n P a rt II
22
Introduction to Wafer Fabrication
• Introduction to TMEC• History from Edison’s Light Bulb to Pentium 4• Semiconductor Materials • Wafer Preparation• Wafer Fabrication Processes• Thin Film Deposition Process• Patterning Process• Etching Process• Doping Process• Contamination
33
Microelectronics Fabrication
Lithography
Etching
Doping
Thin Film Deposition
44
Wafer Fabrication Processes
CMOS Process Bipolar Process
BiCMOS Process
Technologie 0.25µm BiCMOS SiGe,Philips
55
CMOS Process Flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
66
Wafer
p-type Cz wafer
p-type
77
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
88
Initial oxidation: O2/H2 (Thickness: 420 nm)
p-type
n-well
SiO2
99
n-well
Photolithography : NWELL
p-type
Photoresist (PR)
1010
n-well
Dry etch oxide
p-type
1111
n-well
n-well implantation : Phosphorus (3x1012 cm-3, 100 keV)
p-type
1212
Resist strip
p-type
n-well
1313
n-well drive : Anneal : N2
Differential Oxidation : O2/H2 Anneal : N2
p-type
n-well
n-well
1414
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
1515
Active
Wet etch all oxide + Pad oxidation (20 nm)
p-type
n-well
1616
Deposition : Nitride (150 nm)
p-type
n-well
Active
1717
Photolithography : ACTIVE
p-type
n-well
Active
1818
Dry etch nitride
p-type
n-well
Active
1919
Resist strip
p-type
n-well
Active
2020
Photolithography : NFIELD
p-type
n-well
Active
2121
NField implantation : Boron (8x1013 cm-3, 60 keV)
p-type
n-well
Active
2222
Resist strip
p-type
n-well
Active
2323
Field oxidation : O2/H2
p-type
n-well
Active
2424
Active
Wet etch Nitride
p-type
n-well
Active
2525
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
2626
Gate
Etch Pad oxide + WR oxidation : H2/O2 (50 nm)
p-type
n-well
2727
Photolithography : NFIELD
p-type
n-well
Gate
2828
APT Implantation : Boron (6.5x1011 cm-3, 110 keV)
p-type
n-well
Gate
2929
Resist strip
p-type
n-well
Gate
3030
Anneal : N2
p-type
n-well
Gate
3131
Etch WR oxide + Gate oxidation (25 nm)
p-type
n-well
Gate
3232
VTA implantation : Boron (8x1011 cm-3, 20 keV)
p-type
n-well
Gate
3333
Poly deposition
p-type
n-well
Gate
3434
TEOS deposition
p-type
n-well
Gate
3535
Poly implantation : Phosphorus (1.2x1016 cm-3, 50 keV)
p-type
n-well
Gate
3636
Anneal : N2
p-type
n-well
Gate
3737
Wet etch TEOS
p-type
n-well
Gate
3838
Photolithography : POLY
p-type
n-well
Gate
3939
Dry etch poly
p-type
n-well
Gate
4040
Resist strip
p-type
n-well
Gate
4141
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
4242
Junctions
Oxidation : O2
p-type
n-well
4343
Photolithography : NPLUS
p-type
n-well
Junctions
4444
Nplus implantation : Phosphorus (1014 cm-2, 70 keV)Arsenic (6x1015 cm-2, 130 keV)
p-type
n-well
Junctions
4545
Resist strip
p-type
n-well
Junctions
4646
Photolithography : PPLUS
p-type
n-well
Junctions
4747
Pplus implantation :Boron (5x1015 cm-2, 20 keV)
p-type
n-well
Junctions
4848
Resist strip
p-type
n-well
Junctions
4949
Coat front + Backside etch
p-type
n-well
Junctions
5050
Resist strip
p-type
n-well
Junctions
5151
Rapid thermal anneal : N2
p-type
n-well
Junctions
5252
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. Interlayer Dielectric (ILD)7. Contacts and metal 18. Vias and metal 29. Passivation
5353
Interlayer Dielectric
TEOS deposition : UTEOS
p-type
n-well
5454
SOG coatSOG cureSOG coatSOG Cure
p-type
n-well
Interlayer Dielectric
5555
PSG depositionPSG densification
p-type
n-well
Interlayer Dielectric
5656
Coat frontBackside etch
p-type
n-well
Interlayer Dielectric
5757
Resist strip
p-type
n-well
Interlayer Dielectric
5858
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
5959
Contacts and Metal1
Photolithography : CONTACT
p-type
n-well
6060
Dry etch contacts : isotropic + anisotropic
p-type
n-well
Contacts and Metal1
6161
Resist strip
p-type
n-well
Contacts and Metal1
6262
Contract cleanMetal 1 sputtering : TiTiN
AlSiCu TiN
p-type
n-well
Contacts and Metal1
6363
Photolithography : METAL1
p-type
n-well
Contacts and Metal1
6464
Dry etch Metal 1
p-type
n-well
Contacts and Metal1
6565
Resist strip
p-type
n-well
Contacts and Metal1
6666
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
6767
Via and Metal2
Plasma oxide deposition
p-type
n-well
6868
SOG coatSOG cure
p-type
n-well
Via and Metal2
6969
Plasma oxide deposition
p-type
n-well
Via and Metal2
7070
Photolithography : VIA
p-type
n-well
Via and Metal2
7171
Dry etch vias : isotropic + anisotropic
p-type
n-well
Via and Metal2
7272
Resist strip
p-type
n-well
Via and Metal2
7373
Metal2 sputtering : AlsiCu TiN
p-type
n-well
Via and Metal2
7474
Photolithography : METAL2
p-type
n-well
Via and Metal2
7575
Dry etch metal2
p-type
n-well
Via and Metal2
7676
Resist strip
p-type
n-well
Via and Metal2
7777
Process flow
p-type Silicon Substrate
1. Starting wafer2. n-well3. Active4. Gate5. Junction6. ILD7. Contacts and metal 18. Vias and metal 29. Passivation
7878
Passivation
PECVD nitride deposition, Photolithography : PASS, Dry etch nitride, Resist strip, Sintering : Forming gas
p-type
n-well