Aluminum

Concentrations	Etchants	Rate (Å/sec)	Temp
1:1	H2O:HF
1:1:1	HCl:HNO3:H2O
dilute or concentrated	HCl
	H3PO4:HNO3:HAc
19:1:1:2	H3PO4:HAc:HNO3:H2O	40
3:1:3:1	H3PO4:HAc:HNO3:H2O	8.7 @ RT	@ 40 C <4 min/micron
4:4:1:1	H3PO4:HAc:HNO3:H2O	5.6
15:0:1:1-4	H3PO4:HAc:HNO3:H2O	1500	40 C
8:1:1	H3PO4:H2O2:H2O	100	@ 35 C
3:1:5	H3PO4:H2O:glycerin
69:131	HClO4:HAc
4:1:5	HCl:FeCle:H2O
	FeCl3:H2O		100 F
10%	K3Fe(CN)6	100
	KOH:K3Fe(CN)6:K2B4O7.4H2O
2:3:12	KMnO4:NaOH:H2O
1:1:3	NH4OH:H2O2:H2O
20%	NH4SO4
dilute or concetrated	NaOH
8-10%	KOH
	CCl4		boiling
10%	Br2:MeOH		warm

Aluminum Gallium Arsenide

1. 1:1:30 - H₂SO₄:H₂O₂ - 60 angstroms/sec
2. 8:3:400 - NH₃:H₂O₂:H₂O - 25 angstroms/sec
3. 1:1:10 - HF:H₂O₂:H₂O - 80 angstroms/sec

Aluminum Trioxide / Alumina / Sapphire

1. 1:1:3 - NH₄OH:H₂O₂:H₂O - 80 C
2. 10% Br₂:MeOH
3. 7ml:4g - H₃PO:Cr₂O₃

Antimony

1. 1:1:1 - HCl:HNO₃:H₂O
2. 90:10:1 - H₂O:HNO₃:HF
3. 3:3:1:1 - H₃PO₄:HNO₃:CH₃COOH:H₂O<<3min/1000A@50C

Bismuth

1. 10:1 - H₂O:HCl

Brass

1. FeCl₃
2. 20% NHSO₅

Bronze

1. 1% CrO₃

Carbon

1. H₃PO₄:CrO₃:NaCN
2. 50% KOH (or NaOH) - boiling
3. HNO₃ concentrated
4. H₂SO₄ concentrated
5. 3:1 - H₂SO₄:H₂O₂

Chromium

1. 2:3:12 KMnO₄:NaOH:H₂O
2. 3:1 - H₂O:H₂O₂
3. HCl concentrated and dilute
4. 3:1 - HCl:H₂O₂
5. 2:1 - FeCl:HCl
6. Cyantek CR-7s (Perchloric based) 7 min/micron (24A/s new)
7. 1:1 - HCl:glycerine 12min/micron after depassivation
8. 1:3 - [50gNaOH+100mlH₂O]:[30g K₃Fe(CN)₆+100mlH₂O] 1hr/micron

Cobalt

1. 1:1 H₂O:HNO₃
2. 3:1 HCl:H₂O₂

Copper

1. 30% FeCl₃ saturated solution
2. 20% KCN
3. 1:5 - H₂O:HNO₃
4. HNO₃ concentrated and dilute
5. 1:1 - NH₄OH:H₂O₂
6. 1:20 - HNO₃:H₂O₂
7. 4:1 - NH₃:H₂O₂
8. 1:1:1 - H₃PO₄:HNO₃:HAc
9. 5ml:5ml:4g:1:90ml - HNO₃:H2SO₄:CrO₃:NH₄Cl:H₂O
10. 4:1:5 - HCL:FeCl₃:H₂O

Epoxies

1. General Polymer Etch
2. 5:1 - NH₄OH:H₂O₂ - 120 C
3. Gold Epoxy
4. 3:1:10 HNO₃:HCl:H₂O
5. Silver Epoxy
6. 1:3 - HF:HNO₃
7. Aluminum Epoxy
8. H₂SO₄ - hot
9. SU8 cured
10. 3:1 - H₂SO₄:H₂O₂ - hot

Gallium Arsenide

1. 1.5%-7.5% - Br₂ in CH₃OH
2. 1:1 - NH₄OH:H₂O₂
3. 20:7:973 - NH₄OH:H₂O₂:H₂O
4. 40:1:40 - H₃PO₄:H₂O₂:H₂O
5. 3:1:50 - H₃PO₄:H₂O₂:H₂O
6. 33-66% - HNO₃ - red fuming etches more rapidly than white fuming
7. 1:1 - HF:HNO₃
8. 1:1 - H₂SO₄:H₂O₂
9. 1:1:30 - H₂SO₄:H₂O₂ - 60 angstroms/sec
10. 8:3:400 - NH₃:H₂O₂:H₂O - 30 angstroms/sec, isotropic
11. 1:1:10 - HF:H₂O₂:H₂o - 80 angstroms/sec

Germanium

1. HF:HNO₃:H₂O
2. 1:1:1 - HF:HNO₃:HAc
3. 7:1:x HF:HNO₃:glycerin 35c 75-100 microns/hour, 100C 775microns/hour
4. KF - pH > 6
5. 1:25 NH₃OH:H₂O₂ 1000 angstrom/min

Gold

1. Aqua Regia 3:1 - HCl:HNO₃ 10-15 microns/min RT, 25-50 microns/min 35 C
2. Chrome Regia 3:10-20% HCl:CrO₃
3. H₂SeO₄ - Temp should be hot, etch is slow
4. KCN in H₂0 - good for stripping gold from alumina, quartz, sapphire substrates, semiconductor wafers and metal parts
5. 4g:2g:10ml - KI:I₂:H₂O Hot (70C) 280 nm/min
6. 1:2:3 - HF:HAc:HNO₃
7. 30:30:50:0.6 - HF:HNO₃:HAc:Br₂
8. NaCN:H₂O₂
9. 7g:25:g:100ml - KI:Br₂:H₂O
10. 9g:1g:50ml - KBr:Br₂:H₂O 800 nm/min
11. 9g:1g:50ml - NaBr:Br₂:H₂O 400nm/min
12. 400g:100g:400ml - I₂:KI:H₂O 55C 1270A/sec
13. 1:2:10 - I₂:KI:H₂O
14. Au mask etch 4g:1g:40ml - KI:I₂:H₂O 1min/micron

Hafnium

1. 20:1:1 - H₂O:HF:H₂O₂

Indium

1. Aqua Regia 3:1 - HCl:HNO₃ hot
2. HCl boiling, fast
3. IPA
4. EOH
5. MeOH
6. Rare Earth Indium Etchants
   • 1. Br₂:MeOH

Indium Gallium Arsenide

1. 1:1:20 - H₂SO₄:H₂O₂:H₂O - 30 angstroms/sec

Indium Gallium Phosphide

1. conc HCl - fast

Indium Phosphide

1. 1:1 - HCl:H₃PO₄

Indium Phosphide Oxide Etchants

1. NH₄OH

Indium Tin Oxide (ITO)

1. 1:1 - HCl:H₂O 8 angstroms/sec
2. 1:1:10 - HF:H₂O₂:H₂O 125 angstroms/sec

Iridium

1. Aqua Regia 3:1 - HCl:HNO₃ hot

Iron

1. 1:1 - H₂O:HCL
2. 1:1 - H₂O:HNO₃
3. 1:2:10 - I₂:KI:H₂O

Lead

1. 1:1 - HAc:H₂O₂

Magnesium

1. 10ml:1g - H₂O:NaOH followed by 5ml:1g - H2O:CrO3

Molybendum

1. 1:1 - HCl:H₂O₂

Nickel

1. 1:1:1 - HNO₃:HAc:Acetone
2. 1:1 - HF:HNO₃
3. 30% FeCl₃
4. 3:1:5:1 - HNO₃:H₂SO₄:HAc:H₂O 85 C 10 microns/min
5. 3:7 - HNO₃:H2O
6. 1:1 - HNO₃:HAc
7. 10% g/ml Ce(NH₄)₂(NO₃)₆:H₂0
8. HF, concentrated - slow etchant
9. H₃PO₄ - slow etchants
10. HNO₃ - rapid etchant
11. HF:HNO₃ - etch rate determined by ratio, the greater the amount of HF the slower the reaction
12. 4:1 - HCl:HNO₃ - increase HNO₃ concentration increases etch rate
13. 30% FeCl₃
14. 5g:1ml:150ml - 2NH₄NO₃.Ce(NO₃)₃.4(H₂O):HNO₃:H₂O - decreasing HNO₃ amount increases the etch rate
15. 3:3:1:1 - H₃PO₄:HNO₃:CH₃COOH:H₂O ~15min/micron @ RT with air exposure every 15 seconds

Niobium

1. 1:1 - HF:HNO₃

Palladium

1. Aqua Regia 3:1 - HCl:HNO₃ hot

Photoresist (AZ Type)

1. General Polymer
2. 5:1 - NH₄OH:H₂O₂ - 120 C
3. 5:1 - H₂SO₄:H₂O₂
4. H₂SO₄:(NH₄)2S₂O₈
5. Acetone

Platinum

1. Aqua Regia 3:1 - HCl:HNO₃ Hot
2. Molten Sulfur

Polymer

1. 5:1 - NH₄OH:H₂O₂ - 120 C
2. 3:1 - H₂SO₄:H₂O₂

Polymer

1. 1:1 - HF:H₂O
2. 1:1 - HF:HNO₃
3. Sodium Carbonate boiling
4. HF conc

Rhenium, Rhodium, and Ruthenium

1. Aqua Regia 3:1 - HCl:HNO₃ - Hot

Silicon

1. 64:3:33 - HNO₃:NH₄F:H₂O 100 angstroms/s
2. 61:11:28 - ethylenediamine:C₆H₄(OH)₂:H₂O 78 angstroms/s
3. 108ml:350g:1000ml - HF:NH4F:H₂O slow 0.5 angstroms/min
4. 1:1:50 - HF:HNO₃:H₂O slow etch
5. KCl dissolved in H₂O
6. KOH:H₂O:Br2/I2
7. KOH - see section on KOH etching of silicon
8. 1:1:1.4:0.15%:0.24% - HF:HNO₃:HAc:I2:triton
9. 1:6:3 - HF:HNO₃:HAc and 0.19 g NaI per 100 ml solution
10. 1:4 - Iodine Etch:HAc
11. 0.010 N NaI
12. NaOH
13. HF:HNO₃
14. 1:1:1 - HF:HNO₃:H₂O

Silicon Dioxide / Quartz / Glass

1. BOE 1:5:5 HF:NH₄HF:H₂O 20 angstroms/s
2. HF:HNO₃
3. 3:2:60 HF:HNO₃:H₂0 2.5 angstroms/sec at RT
4. BHF 1:10, 1:100, 1:20 HF:NH₄F(sat)
   • 3ml:15g:22ml HF:NH₄F:H₂O
5. Secco etch 2:1 HF:1.5M K₂Cr₂O₇
6. Secco etch 2:1 HF:1.5M K₂Cr₂O₇
7. 5:1 NH₄.HF:NaF/L (in grams)
8. 1g:1ml:10ml:10ml NH₄F.HF:HF:H₂O:glycerin
9. HF - hot
10. 1:1 1:15, 1:100 HF:H₂O
11. BOE HF:NH₄F:H₂O
12. 1:6 BOE:H₂O
13. 5:43, 1:6 HF:NH₄F(40%)
14. NaCO3 100 C 8.8 mm/h
15. 5% NaOH 100 C 150 mm/h
16. 5% HCl 95 C 0.5mm/day
17. KOH see KOH etching of silicon dioxide and silicon nitride

Silicon Nitride

1. 1:60 or 1:20 HF:H₂O 1000-2000 A/min
2. BHF 1:2:2 HF:NH₄F:H₂O slow attack - but faster for silicon oxynitride
3. 1:5 or 1:9 HF:NH₄F (40%)0.01-0.02 microns/second
4. 3:25 HF:NH₄F.HF(sat)
5. 50ml:50g:100ml:50ml HF:NH₄F.HF:H₂O:glycerin - glycerin provides more uniform removal
6. BOE HF:NH₄F:H₂O
7. 18g:5g:100ml NaOH:KHC₈H₄O₄:H₂O boiling 160 A/min, better with silicon oxynitride
8. 9:g25ml NaOH:H20 - boiling 160A/min
9. 18g:5g:100ml NaOH:(NH₄)2S₂O₈:H₂O - boiling 160 A/min
10. A) 5g:100ml NH₄F.HF:H₂O B)1g:50ml:50ml I₂:H₂O:glycerin - mix A and B 1:1 when ready to use. RT 180 A/min

Silver

1. 1:1 NH₄OH:H₂O₂
2. 3:3:23:1 H₃PO₄:HNO₃:CH₃COOH:H₂O ~10min/100A
3. 1:1:4 NH₄OH:H₂O₂:CH₃OH .36micron/min resist
4. 1:1:1 HCl:HNO₃:H₂O
5. 1-8:1HNO₃:H₂O
6. 1 M HNO₃ + light

Stainless Steel

1. 1:1 HF:HNO₃

Tantalum

1. 1:1 HF:HNO₃

Tin

1. 1:1 HF:HCL
2. 1:1 HF:HNO₃
3. 1:1 HF:H₂O
4. 2:7 HClO₄:HAc

Titanium

1. 50:1:1 H₂O:HF:HNO₃
2. 20:1:1 H₂O:HF:H₂O₂
3. RCA-1 ~100 min/micron
4. x%Br₂:ethyl acetate - HOT
5. x%I₂:MeOH - HOT
6. HF:CuSO₄
7. 1:2 NH₄OH:H₂O₂
8. 1:2:7, 1:5:4, 1:4:5(18 microns/min), 1:1:50 HF:HNO₃:H₂O
9. COOHCOOH:H₂O - any concentration
10. 1:1:20 HF:H₂O₂:HNO₃
11. 1:9 HF:H₂O - 12 A/MIN
12. HF:HCL:H₂O
13. HCL - conc
14. %KOH - conc
15. %NaOH- conc
16. 20% H₂SO₄ 1 micron/min
17. CCl₃COOC₂h₃
18. 25%HCOOH
19. 20%H₃PO₄
20. HF

Tungsten

1. 1:1 HF:HNO₃
2. 1:1 HF:HNO₃ - thin films
3. 3:7 HF:HNO₃
4. 4:1 HF:HNO₃ - rapid attack
5. 1:2 NH₄OH:H₂O₂ - thin films good for etching tungsten from stainless steel, glass, copper and ceramics. Will etch titanium as well.
6. 305g:44.5g:1000ml K₃Fe(CN)₆:NaOH:H₂O - rapid etch
7. HCl - slow etch (dilute or concentrated)
8. HNO₃ - very slow etch (dilute or concentrated)
9. H₂SO₄ - slow etch (dilute or concentrated)
10. HF - slow etch (dilute or concentrated)
11. H₂O₂
12. 1:1, 30%:70%, or 4:1 HF:HNO₃
13. 1:2 NH₄OH:H₂O₂
14. 4:4:3 HF HNO₃:HAc
15. CBrF₃ RIE etch
16. 305g:44.5g:1000ml K₃Fe(CN)₆:NaOH:H₂O - very rapid etch
17. HCl solutions - slow attack
18. HNO₃ - slight attack
19. Aqua Regia 3:1 HCL:HNO₃ - slow attack when hot or warm
20. H₂SO₄ dilute and concentrated - slow etch
21. HF dilute and concentrated - slow etch
22. Alkali with oxidizers (KNO₃ and PbO₂) - rapid etch
23. H₂O₂

Vanadium

1. 1:1 H₂O:HNO₃
2. 1:1 HF:HNO₃

Zinc

1. 1:1 HCl:H₂O
2. 1:1 HNO₃:H₂O

Zinc Oxide

1. 1:60 HCl:H₂O - 1.9 microns/min
2. 1:200 Hcl:H₂O - 0.9 microns/min
3. 1:500 HCl:H₂O - 0.4 microns/min
4. 1:900 HCl:H₂O - 0.2 microns/min
5. 1:100 HNO₃:H₂O - 0.9 microns/min
6. 1:7 BOE - .06 microns/min
7. 1:1:30 H₃PO₄:C₆H₈O₇:H₂O - 2.2 microns/min
8. 1:5:60 H₃PO₄:C₆H₈O₇:H₂O - 1.8 microns/min
9. 1:1:80 H₃PO₄:C₆H₈O₇:H₂O - 1.4 microns/min
10. 1:1:150 H₃PO₄:C₆H₈O₇:H₂O - 1 micron/min
11. 1:1:200 H₃PO₄:C₆H₈O₇:H₂O - 0.8 microns/min
12. 1:2:300 H₃PO₄:C₆H₈O₇:H₂O - 0.65 microns/min

Zirconium

1. 50:1:1 H₂O:HF:HNO₃
2. 20:1:1 H₂O:HF:H₂O₂