Wet Etching Recipes

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Table of Wet Etching Recipes

Use the ↑ ↓ Arrows in the header row to sort the entire table by material, selectivity, etchant etc.

Material Etchant Rate (nm/min) Anisotropy Selective to Selectivity Ref. Notes Confirmed By/Date
Photoresist, polymers/organics H2SO4:H2O2 = 3:1

Piranha Solution

typ. 5-10min etch for polymer residue Cr, W, Au, Pt, Si, SiO2, SiN Dangerous boiling hazard - see Piranha Solution

section below. Etches Ti

Demis D. John, 2017
InP H3PO4:HCl = 3:1 ~1000 Highly InGaAsP High Lamponi (p.102)
InGaAsP To Be Added InP High
InP H3PO4:HCl = 3:1 ~1000 Highly InGaAs High Lamponi (p.102)
InP HCl:H2O = 3:1 ~5000 InGaAs

~200nm stop-etch

High Bubbles while etching
InGaAs H2SO4:H2O2:H2O = 1:1:10 ~600 InP High Exothermic, may reduce selectivity if hot
GaAs NH4OH:H2O2 = 1:30 - AlGaAs,

Al > 80%

~200nm stop-etch

High Garrett Cole
AlGaAs,

Al ≥80%

HF:H2O = 1:20 - GaAs High Garrett Cole
Oxide of InP NH4OH:H2O = 1:10 1min to remove InP unknown Ning Cao
Oxide of GaAs HCl:H2O = 1:10 1min to remove GaAs unknown Demis D. John
Al2O3 (ALD Plasma 300C) Developer: 300MIF ~1.6 None Most non-Al Materials. High Measured in-house Rate slows with time. JTB
Al2O3 (ALD Plasma 300C) Developer: 400K ~2.2 None Most non-Al Materials. High Measured in-house Rate slows with time. JTB
Al2O3 (ALD Plasma 300C) Developer: 400K (1:4) ~1.6 None Most non-Al Materials. High Measured in-house Rate slows with time. JTB
Al2O3 (ALD Plasma 300C) NH4OH:H2O2:H2O (1:2:50) ~<0.5 Measured in-house Rate slows with time JTB
Al2O3 (IBD) HF ("Buffered HF Improved", Transene) ~170 None Photoresist High Measured in-house May need to increase adhesion with thin SiO2 layer, and 100°C baked HMDS. Biljana Stamenic,

2017-12

Al2O3 (IBD) Developer: 726 MiF 3.5 None Most non-Al Materials. High Measured in-house Demis D. John,

2017-11

Al2O3 (AJA#4) Developer: 300 MiF 4.30 None Most non-Al Materials. High Measured in-house Demis D. John

2018-02

SiO2 (PECVD #1) HF ("Buffered HF Improved", Transene) ~500 None Photoresist High Measured in-house May need to increase adhesion with 100°C baked HMDS. Biljana Stamenic

2017

SiO2 (PECVD #2) HF ("Buffered HF Improved", Transene) ~500 None Photoresist High Measured in-house May need to increase adhesion with 100°C baked HMDS. Biljana Stamenic

2017

SiO2 (IBD) HF ("Buffered HF Improved", Transene) ~350 None Photoresist High Measured in-house Biljana Stamenic

2016

Si3N4 (PECVD#1) HF ("Buffered HF Improved", Transene) 85 None Photoresist High Measured in-house Biljana Stamenic

2018-04

Si3N4 (PECVD#2) HF ("Buffered HF Improved", Transene) 35–45 None Photoresist High Measured in-house Biljana Stamenic

2018-05

Si3N4 Low-Stress (PECVD#2) HF ("Buffered HF Improved", Transene) 35–50 None Photoresist High Measured in-house Biljana Stamenic

2018-05

Si3N4 (IBD) HF ("Buffered HF Improved", Transene) 5–15 None Photoresist High Measured in-house Biljana Stamenic

2014

Ta2O5 (IBD) HF ("Buffered HF Improved", Transene) 0.4 None Photoresist High Measured in-house Biljana Stamenic

2016-12

TiO2 (IBD) HF ("Buffered HF Improved", Transene) 1.0–2.0 None Photoresist High Measured in-house Biljana Stamenic

2014-12

Si (<100> crystalline) KOH (45%) @ 87°C ~730 High, Crystallographic, ~55° Low-Stress Si3N4 - either PECVD #2 or Commercial LPCVD Si3N4

Other Si3N4 also OK.

LS-SiN: High

PR etches quickly, SiO2 etches slowly.

Measured In-House

- Search online.

Use the Covered, Heated vertical bath (Dedi cated bath in Bay 4). Slight Bubbler. Brian Thibeault

2017

Material Etchant Rate (nm/min) Anisotropy Selective to Selectivity Ref. Notes Confirmed By/Date

Wet Etching References

  1. Etch rates for Micromachining Processing (IEEE Jnl. MEMS, 1996) - includes tables of etch rates of numerous metals vs. various wet and dry etchants.
  2. Etch rates for micromachining-Part II (IEEE Jnl. MEMS, 2003) - expanded tables containing resists, dielectrics, metals and semiconductors vs. many wet etch chemicals.
  3. Guide to references on III±V semiconductor chemical etching - exhaustive list of wet etchants for etching various semiconductors, including selective etches.
  4. Transene's Chemical Compatibility Chart provides a useful quick-reference for which Transene etchants attack which materials.
    1. As a side-note, Transene provides many pre-mixed solutions that you can order, saving you the time and uncertainty of measuring/mixing such chemicals yourself. Make sure you check with us before ordering so we know how to handle the chemical before it arrives.

Compound Semiconductor Etching

Guide to references on III±V semiconductor chemical etching

Please add any confirmed etches from this reference to the The Master Table of Wet Etching (Include All Materials).

Metal Etching

Silicon etching

Etch rates for micromachining processing

Etch rates for micromachining processing-part II

Please add any confirmed etches from this reference to the The Master Table of Wet Etching (Include All Materials).

Organic removal

Piranha Solution

PureStrip (Transene)

Gold Plating

To Be Added

Chemi-Mechanical Polishing (CMP)

To Be Added

Mechanical Polishing (Allied)

To Be Added