Microelectronics Research Center

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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 ? RateAlso etches—Doesn’t etch—
Aluminum (Al)
 19 H3PO4 : 1 HAc : 1 HNO3 : 2 H2O40 Å/sSiN, MSiO2, Si, PR
10% K3Fe(CN)6100 Å/s ZnO, SiO2, SiN, Si, M, PR
Aluminum Oxide (Al2O3)
 1 NH4OH : 1 H2O2 : 3 H2O @ 80 ºC Al, PolySiO2, SiN, Si, M
Brass (alloy Cu : Zn)
 FeCl3 Cu, NiSiO2, SiN, Si, M, PR
20% NH4SO5 AlSiO2, SiN, Si, M, PR
Bronze (alloy Cu : Sn)
 1% CrO3  SiO2, SiN, Si, PR
Carbon (C)
 H3PO4 : CrO3 : NaCN SiNSiO2, Si, PR
Chromium (Cr)
 2 KMnO4 : 3 NaOH : 12 H2O AlSiO2, SiN, Si, M, PR
Copper (Cu)
 30% FeCl3 NiSiO2, SiN, Si, M, PR
20% KCN Ag, AuAl2O3, SiO2, SiN, Si, M, PR
Gallium Arsenide (GaAs)
 5% Br2 in CH3OH FeSiO2, SiN, Si, M
1 NH4OH : 1 H2O2 Al, Ag, PolySiO2, SiN, Si, M
Gold (Au)
 1 I2 : 2 KI : 10 H2O FeSiO2, SiN, Si, M, PR
KCN Ag, CuAl2O3, SiO2, SiN, Si, M, PR
Iron (Fe)
 1 I2 : 2 KI : 10 H2O AuSiO2, SiN, Si, M, PR
Nickel (Ni)
 30% FeCl3 CuSiO2, SiN, Si, M, PR
Polymers (e.g.: photoresist, wax, epoxies)
 5 NH4OH : 1 H2O2 @ 120 ºC AlSiO2, SiN, Si, M
Silicon (Si)
 64 HNO3 : 3 NH4F : 33 H2O100 Å/sMSiN, PR
61 EDA : 11 C6H4(OH)2 : 28 H2O78 Å/sPolySiO2, SiN, M
Silicon Oxide (SiO2)
 1 HF : 5 NH4HF : 5 H2O (BOE) 20 Å/sM, SiO2SiN, Si
Silver (Ag)
 1 NH4OH : 1 H2O2 Al, PolySiO2, SiN, Si, M
Stainless Steel (alloy Fe : C : Cr)
 1 HF : 1 HNO3 MSiN, PR
Tin (Sn)
 2 HClO4 : 7 HAc  SiO2, SiN, Si, PR

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