Baseline CMOS Process (4")

Version 5.0 (Nov. 1997 – 2001)

1.3 µm, twin-well, double poly-Si, double metal

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0.0 Starting Wafers: 24-36 ohm-cm, p-type, <100>

Control wafers: PCH, NCH.

Scribe lot and wafer number on each wafer, including controls.

Piranha clean and dip in sink8.

R =

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1.0 Initial Oxidation: target = 30 (± 5 %) nm

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1.1 TCA clean furnace tube (tylan5), reserve tylan9.

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1.2 Standard clean wafers in sink6:

Include PCH and NCH.

piranha 10 minutes, 10/1 HF dip, spin-dry.

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1.3 Dry oxidation at 950ºC (SGATEOX):

60 min. dry O₂ (Check the previous run result)

20 min. dry N₂

Ox. Time =

measure oxide thickness on PCH, Tox =

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2.0 Nitride Deposition (SNITC):

Transfer wafers to tylan9 right after 1.3 and deposit

Only include NCH

100 nm nitride Dep. Time =

measure nitride thickness on NCH, Tnit =

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3.0 Well Photo: Mask NWELL (CWN chrome-df)

(Control wafers are not included in any photoresist step)

Standard I-line process:

HMDS, spin (and soft bake), expose, post exposure bake,

develop, inspect, descum and hard bake.

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4.0 Etch: Plasma etch nitride in lam1.

Recipe: Power:

Actual Etch Time: Overetch:

Check the oxide thickness on each work wafer:

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5.0 N-Well Implant: phosphorus, 4E12/cm2, 80 KeV. Include PCH.

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6.0 N-Well Cover Oxidation:

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6.1 TCA clean furnace tube (tylan2).

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6.2 Remove PR in O₂ plasma and clean wafers in sink8.

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6.3 Standard clean wafers in sink6, include PCH and NCH.

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6.4 Well cover oxidation at 950 (NWELLCVR):

30 min. dry O₂

175 min. wet O₂

30 min. dry O₂

20 min. N₂

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7.0 Nitride Removal, include NCH

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7.1 Dip in 10:1 BHF for 40 sec to remove thin oxide on top of Si3N4.\

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7.2 Etch nitride off in boiling phosphoric acid (sink7).

Measure Tox in n-well on work wafers.

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8.0 P-Well Implant: B11, 3E12/cm2, 80 KeV. Include NCH

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9.0 Well Drive-In:

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9.1 TCA clean furnace tube (tylan2).

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9.2 Standard clean wafers in sink8 and 6. Include PCH and NCH.

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9.3 Well drive at 1120ºC (WELLDR):

60 min. temperature ramp from 750ºC to 1120ºC

240 min. dry O₂

300 min. N₂

Measure oxide thickness on two control wafers.

tox (PCH)= tox (NCH) =

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9.4 Strip oxide in 5:1 BHF.

Measure Rs on PCH and NCH.

Rs (PCH) = Rs(NCH) =

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10.0 Pad Oxidation/Nitride Deposition:

target = 30 (+6) nm Si O₂ + 100 (+10) nm Si3N4

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10.1 TCA clean furnace tube (tylan5). Reserve tylan9.

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10.2 Standard clean wafers. Include PCH, NCH.

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10.3 Dry oxidation at 950ºC (SGATEOX):

~1 hr dry O₂

30 minutes dry N₂ anneal

Measure the oxide thickness on NCH

Tox =

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10.4 Deposit 100 (+10) nm of Si3N4 immediately (SNITC):

Only include PCH

Approximate time = 22 min, temp.= 800ºC

Measure nitride thickness on PCH

Tnit =

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11.0 Active Area Photo: Mask ACTV (ACTV emulsion-cf)

Standard I-line process.

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12.0 Nitride Etch:

Plasma etch nitride in lam1. Recipe:

Power: Time: Overetch:

Measure Tox on each work wafer. (2 pnts measurement)

Do not remove PR. Inspect.

Measure PR thickness covering active area. Tpr =

PR must be >800 nm. Hard bake again for >2hrs at 120ºC.

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13.0 P-Well Field Implant Photo: Mask PFIELD (CWNI emulsion-cf)

(Reversed NWELL mask)

Standard I-line process. (Second photo)

N-Well area is covered with PR.

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14.0 P-Well Field Ion Implant: B11, 70 KeV, 1.5E13/cm2.

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15.0 N-Well Field Implant Photo: Mask NWELL (CWN chrome-df)

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15.1 Remove PR in plasma O₂. Clean wafers in sink8.

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15.2 Standard I-line process.

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16.0 N-Well Field Ion Implant: phosphorus, 40 KeV, 3E12.

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17.0 Locos Oxidation: target = 650 nm

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17.1 TCA clean furnace tube (tylan2).

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17.2 Remove PR in O₂ plasma and piranha clean wafers.

Standard clean wafers; dip in BHF 25:1 for 5-10 sec.

Include PCH, NCH.

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17.3 Wet oxidation at 950ºC (SWETOXB):

5 min. dry O₂

4 hrs. 40 min. wet O₂

5 min. dry O₂

20 min. N₂ anneal

Measured tox on 3 work wafers. Tox =

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18.0 Nitride Removal, include PCH.

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18.1 Dip in 10:1 BHF for 60 sec to remove thin oxide on top of Si3N4.

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18.2 Etch nitride off in phosphoric acid at 145ºC (sink7)

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19.0 Sacrificial Oxide: target = 20 (± 2) nm

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19.1 TCA clean furnace tube (tylan5).

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19.2 Standard clean wafers, include NCH and PCH.

Dip in 10:1 BHF until PCH and NCH dewet.

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19.3 Dry oxidation at 950ºC (SGATEOX):

30 minutes dry O₂

30 minutes N₂ anneal

Measure Tox on PCH and NCH. Tox =

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20.0 N-Channel Punchthrough and Threshold Adjustment Photo: Mask PFIELD

(CWNI emulsion-cf)

Standard I-line process

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21.0 N-Channel Punchthrough and Threshold Adjustment Implant. Include NCH.

1) B11, 120 KeV, 8E11/cm2.

2) B11, 30 KeV, 1.9E12/cm2.

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22.0 P-Channel Punchthrough and Threshold Adjustment Photo: Mask PVT

(PVT chrome-df).

Remove PR in plasma O₂ and clean wafers in sink8.

Standard I-line process.

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23.0 P-Channel Punchthrough and Threshold Adjustment Implant. Include PCH.

1) Phosphorus, 190 KeV, 1E12,

2) B11, 20 KeV, 2.4E12.

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24.0 Gate Oxidation/Poly-Si Deposition:

target = 20 (± 2.0) nm Si O₂ + 450 (± 40) nm poly-Si

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24.1 TCA clean furnace tube (tylan5)

Reserve poly-Si deposition tube (tylan11)

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24.2 Standard clean wafers, include PCH, NCH,

Tox (prime P<100>), and one Tpoly1 monitoring wafers.

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24.3 Dip off sacrificial oxide in 10:1 HF

until NCH and PCH dewet (approx. 1 min)

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24.4 Dry oxidation at 950ºC (SGATEOX):

30 min dry O₂ (Check previous run result)

30 min N₂ anneal.

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24.5 Immediately after oxidation deposit 450 nm of phos.doped

poly-Si (SDOPOLYI).

only include Tpoly1.

approx.time = 2 hr. 20 min., temp.= 610ºC

(Check previous run result)

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24.6 Measurements

a) Measure oxide thickness on Tox, PCH and NCH.

b) Measure Dit and Qox on Tox.

c) Strip oxide from PCH and NCH, and measure the sheet resistivity.

d) Measure poly thickness on Tpoly1.

PCH and NCH proceed to step 27.2.

Tpoly1 proceeds to step 32.3.

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25.0 Gate Definition: Mask POLY (emulsion-cf)

Standard I-Line process.

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26.0 Plasma etch poly-Si

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26.1 Etch poly in Lam4 (Recipe: 400):

Pwr: Ave. etch time: Overetch:

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26.2 Measure Tox in S/D area of each work wafer (2 pnts measurement).

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26.3 Measure channel length using 1.0µm gate.

CD =

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27.0 Reoxidation and Capacitor Formation:

(If no capacitor is requested, skip step 27 through 29.2.)

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27.1 TCA clean furnace tube (tylan2). Reserve tylan12 and tylan11.

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27.2 Standard clean wafers, including PCH, NCH, and

two monitoring wafers, one for dry oxidation (Tpoly2) and

one for LTO.

From here on: only 10 sec dip in 25/1 H2O/HF after piranha.

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27.3 Dry oxidation at 900ºC (SDRYOXB):

30 min dry O₂

20 min N₂ anneal.

Measure oxide thickness on Tpoly2:

Tpoly2 proceeds to Step 27.5.

PCH proceeds to Step 34 and NCH proceeds to Step 31.

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27.4 1) Run a coating and monitoring LTO in tylan12 to get

dep rate. Use recipe VDOLTOC and set 0 doping.

2) Deposit LTO for the desired oxide thickness.

3) Measure LTO thickness on monitoring wafer:

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27.5 Second poly-Si deposition: immediately after oxidation

deposit 450 nm of phos.doped poly-Si (SDOPOLYH):

only include Tpoly2.

approx.time = 2 hr. 18 min, temp.= 610ºC.

Measure second poly thickness on Tpoly2:

Tpoly2 proceeds to step 32.3.

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28.0 Capacitor Photo: Mask CAP-CE (CAP emulsion-cf)

Standard I-Line process.

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29.0 Plasma etch poly-Si:

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29.1 Etch 2nd poly in Lam4 (Recipe: 400):

Power: Actual etch time: Overetch:

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29.2 Measure Tox in S/D area on each work wafer.

Remove PR in O₂ plasma.

Piranha clean wfrs in sink8.

Dehydrate wfrs in oven for > 30 min. at 120ºC.

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30.0 N+ S/D Photo: Mask N+S/D (NSD chrome-df)

Standard I-line process

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31.0 N+ S/D Implant: Arsenic, 100 keV, 5E15/cm2, include NCH.

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32.0 N+ S/D Anneal

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32.1 TCA clean furnace tube (tylan7).

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32.2 Remove PR in O₂ plasma and piranha clean wafers

in sink8 (no dip here).

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32.3 Standard clean wafers in sink6, incl. PCH, NCH, Tpoly1,

and Tpoly2.

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32.4 Anneal in N₂ at 900ºC for 30 min (N₂ANNEAL).

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32.5 Strip oxide from NCH, Tpoly1, and Tpoly2.

Measure Rs of N+ S/D implant: Rs(NCH)=

Measure Rs of poly1 on Tpoly1: Rs(Tpoly1)=

Measure Rs of poly2 on Tpoly2: Rs(Tpoly2)=

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33.0 P+ S/D Photo: Mask P+S/D (PSD emulsion-cf)

Standard I-line process.

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34.0 P+ S/D Implant: B11, 20 keV, 5E15/cm2, include PCH.

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35.0 PSG Deposition and Densification: target = 700 nm

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35.1 Remove PR in O₂ plasma and clean wafers in sink8 (no dip).

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35.2 Standard clean wafers in sink6 (10 sec dip).

Include one PSG monitoring wafer.

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35.3 Deposit 700 nm PSG, PH3 flow at 10.3 sccm (SDOLTOD).

approx.time = 22 min. (check current dep. rate)

temp. = 450ºC

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35.4 Densify glass in tylan2 at 900ºC, immediately after

PSG deposition (PSGDENS). Include PSG control.

5 min dry O₂

20 min wet O₂

5 min dry O₂

Measure tPSG (using PSG control and working wafers):

N+ region Tox =

P+ region Tox =

Etch oxide on PCH.

Measure Rs of P+ S/D implant: Rs(PCH)=

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35.5 Do wet oxidation dummy run afterwards to clean tube:

1 hr wet oxidation at 950ºC (SWETOXB).

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36.0 Contact Photo: Mask CONT (CONT chrome-df)

Standard I-Line process.

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37.0 Contact Plasma Etch in lam2:

Recipe: Power: Etch time: Overetch:

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38.0 Back side etch:

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38.1 Remove PR in O₂ plasma, piranha clean wafers in sink8 (no dip).

Dehydrate wafers in oven at 120ºC for >30 min.

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38.2 Etch backside:

(PCH and NCH can be included in b), c) and d).

a) Spin PR on front side, hard bake.

b) Dip off oxide (PSG) in 5:1 BHF.

c) Etch poly-Si (poly2 thickness) in lam4.

d) Etch oxide off in 5:1 BHF (cap. ox. thickness).

e) Etch poly-Si (poly1 thickness) in lam1.

f) Final dip in BHF until back dewets.

g) Remove PR in PRS2000, piranha clean wfrs in sink8

(no dip).

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39.0 Metallization: target = 600 nm

Stnd clean wfrs and do a 30 sec. 25/1 H2O/HF dip just

before metallization.

Sputter Al/2% Si on all wafers in CPA.

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40.0 Metal Photo: Mask METAL1-CM (M1 emulsion-cf)

Standard I-line process.

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41.0 Plasma etch Al in Lam3

Remove PR in PRS2000 or technics-c. tAl =

Probe test devices.

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42.0 Sintering: 400ºC for 20min in forming gas (tylan13).

No ramping, use SINT400 program.

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43.0 Testing:

1.0 µm N- and P-channel devices, capacitors and inverter

Measure the sheet resistivities of PCH and

NCH on prometrix.

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