Understand the possible reactions when mixing chemicals.
Many processing steps require mixing liquid chemicals together. Users should make themselves aware of the chemical reactions possible when mixing chemicals in order to minimize the risk to themselves and others around.
For example, always add acids to water. Adding water to an acid causes a highly exothermic reaction which can cause a fire and release dangerous gases into the air.
Please use the tables below with care.
Etchant
|
Materials Etched
|
| Acetic Acid (H3COOH) |
GaAs; Pb; Ti |
| Hydrochloric Acid (HCl) |
Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In; Fe; Pb; Ni; NiO, Ni2O3; Sn; SnO2; Ti; Zn |
| Hydrofluoric Acid (HF) |
GaAs; Ni; SiO2; Ti |
| Nitric Acid (HNO3) |
C; Cu; GaAs; In; Fe; Pb; Ni; Ag; Pd; Pt; Sn; Ti; Zn; ZnO |
| Phosphoric Acid (H3PO4) |
Al; Cu; GaAs; GaN; Fe; Ni; SiN; ZnO |
| Potassium Hydroxide (KOH) |
Al; C; Cu; Ag; GaAs; Si; Ti |
| Sodium Hydroxide (NaOH) |
Al; Cu; Ag; Ti; GaAs; GaN |
| Sulfuric Acid (H2SO4) |
C; Cu; GaAs; Fe; Pb; Ni; Ti |
| Aqua Regia (3 HCl : 1 HNO3) |
etches all metals |
| |
|
Etchant
|
Rate
|
Also etches
|
Doesn't etch
|
| Aluminum (Al) |
| |
19 H3PO4 : 1 HAc : 1 HNO3 : 2 H2O |
40 �/s |
SiN, M |
SiO2, Si, PR |
| 10% K3Fe(CN)6 |
100 �/s |
|
ZnO, SiO2, SiN, Si, M, PR |
| Aluminum Oxide (Al2O3) |
| |
1 NH4OH : 1 H2O2 : 3 H2O @ 80 �C |
|
Al, Poly |
SiO2, SiN, Si, M |
| Brass (alloy Cu : Zn) |
| |
FeCl3 |
|
Cu, Ni |
SiO2, SiN, Si, M, PR |
| 20% NH4SO5 |
|
Al |
SiO2, SiN, Si, M, PR |
| Bronze (alloy Cu : Sn) |
| |
1% CrO3 |
|
|
SiO2, SiN, Si, PR |
| Carbon (C) |
| |
H3PO4 : CrO3 : NaCN |
|
SiN |
SiO2, Si, PR |
| Chromium (Cr) |
| |
2 KMnO4 : 3 NaOH : 12 H2O |
|
Al |
SiO2, SiN, Si, M, PR |
| Copper (Cu) |
| |
30% FeCl3 |
|
Ni |
SiO2, SiN, Si, M, PR |
| 20% KCN |
|
Ag, Au |
Al2O3, SiO2, SiN, Si, M, PR |
| Gallium Arsenide (GaAs) |
| |
5% Br2 in CH3OH |
|
Fe |
SiO2, SiN, Si, M |
| 1 NH4OH : 1 H2O2 |
|
Al, Ag, Poly |
SiO2, SiN, Si, M |
| Gold (Au) |
| |
1 I2 : 2 KI : 10 H2O |
|
Fe |
SiO2, SiN, Si, M, PR |
| KCN |
|
Ag, Cu |
Al2O3, SiO2, SiN, Si, M, PR |
| Iron (Fe) |
| |
1 I2 : 2 KI : 10 H2O |
|
Au |
SiO2, SiN, Si, M, PR |
| Nickel (Ni) |
| |
30% FeCl3 |
|
Cu |
SiO2, SiN, Si, M, PR |
| Polymers (e.g.: photoresist, wax, epoxies) |
| |
5 NH4OH : 1 H2O2 @ 120 �C |
|
Al |
SiO2, SiN, Si, M |
| Silicon (Si) |
| |
64 HNO3 : 3 NH4F : 33 H2O |
100 �/s |
M |
SiN, PR |
| 61 EDA : 11 C6H4(OH)2 : 28 H2O |
78 �/s |
Poly |
SiO2, SiN, M |
| Silicon Oxide (SiO2) |
| |
1 HF : 5 NH4HF : 5 H2O (BOE) |
20 �/s |
M, SiO2 |
SiN, Si |
| Silver (Ag) |
| |
1 NH4OH : 1 H2O2 |
|
Al, Poly |
SiO2, SiN, Si, M |
| Stainless Steel (alloy Fe : C : Cr) |
| |
1 HF : 1 HNO3 |
|
M |
SiN, PR |
| Tin (Sn) |
| |
2 HClO4 : 7 HAc |
|
|
SiO2, SiN, Si, PR |
Chemical Formula/Symbol
|
Chemical Name/Notation
|
| H2O |
deionized (DI) water (l) |
| HCl |
hydrochloric acid (38%, aq) |
| HF |
hydrofluoric acid (49%, aq) |
| HNO3 |
nitric acid (70%, aq) |
| H2SO4 |
sulfuric acid (96%, aq) |
| H3PO4 |
phosphoric acid (85%, aq) |
| HAc |
acetic acid (l, H3COOH) |
| HClO4 |
perchloric acid (68%, aq) |
| H2O2 |
hydrogen peroxide (30%, aq) |
| NH4OH |
ammonium hydroxide (30%, aq) |
| NH4F |
ammonium fluoride (40%, aq) |
| CH3OH |
methanol (l) |
| EDA |
ethylenediamine (l, NH2O(CH2) 2NH2) |
| C6H4(OH)2 |
pyrocatechol (s) |
| NaOH |
sodium hydroxide (s) |
| KOH |
potassium hydroxide (s) |
| KCN |
potassium cyanide (s) |
| NaCN |
sodium cyanide (s) |
| KFe(CN)6 |
potassium ferrocyanide (s) |
| KMnO4 |
potassium permanganate (s) |
| FeCl3 |
ferric chloride (s) |
| NH4SO5 |
ammonium persulfate (s) |
| KI |
potassium iodide (s) |
| I2 |
iodine (s) |
| Br2 |
bromine (l) |
| CrO3 |
chromic oxide (s) |
| SiO2 |
silicon oxide |
| SiN |
silicon nitride (Si3N4, Si9N12) |
| Si |
mono- or polycrystalline silicon |
| M |
metals |
| PR |
photoresist (cured) |
| Poly |
other polymers |