Wet Chemistry Resources

Sample Cleaning Resources

• Handbook of Silicon Wafer Cleaning Technology

• UC Irvine Cleaning Procedures for Silicon

• BYU Substrate Cleaning Guide

• https://www.microsi.com/silicon-wafer-cleaning/

Solvent Cleans

• UIUC Wafer Cleaning Procedure

• Acetone, IPA -Acetone serves as a solvent for organics, IPA cleans remaining residues due to acetone's high evaporation rate
• Acetone, Methanol -Similar to above except Methanol is more toxic, and a polar molecule versus IPA which is non-polar
• Acetone, Methanol, IPA
• Acetone, Methanol, IPA, DI Water
• Remover PG (60°C), IPA -Caution, low flashpoint, do not leave unattended
  • Nano Remover PG Spec Sheet
  • Columbia University Remover PG Process
• Dichloromethane, IPA -Caution, high evaporation rate may leave residue and beakers quickly condense water/ice

Etching Cleans

Caution. All of these processes require a buddy and adequate chemical safety training.

RCA Clean

Prepares wafers for high-temperature processing steps. Standardized protocol developed by RCA in 1960s.

• https://en.wikipedia.org/wiki/RCA_clean

Nanostrip Etch

Strong oxidant solution, removes organics and some metals from surfaces and reestablishes oxidized surface. If there is significant organic contamination, perform solvent clean prior.

• Nanostrip (60°C) -Rinse with DI
  • https://www.seas.upenn.edu/~nanosop/Nanostrip_SOP.htm
  • https://braungroup.beckman.illinois.edu/files/2018/02/SOP_BI-005_Nanostrip.pdf

Piranha Etch

Strong oxidant solution, removes organics and some metals from surfaces and reestablishes oxidized surface. If there is significant organic contamination, perform solvent clean prior.

• Caltech MMRC Piranha Etch

• UMich LNF Piranha Etch

• McMaster University Piranha Etch

• Boston University Piranha Etch

HF Dip

Removes native oxide from surfaces.

• UCI Irvine HF 2% Dip

• UBC BOE Etch and HF Dip

Plasma Cleans

Plasma cleaning via oxygen, argon, etc. may be the more optimal choice for certains samples such as fragile membranes. More information can be found on the tool page for the Tergeo Plus Plasma Cleaner.

Wet Etching Resources

Reference Articles and Texts

• Etch Rates for Micromachining Processing

• Etch Rates for Micromachining Processing-Part II

• Handbook of Metal Etchants

External Laboratories

• BYU Etching list

• UMich Wet Etching info

• BYU Etching Guidance

• UCSB Wet Etching Recipes

• Berkeley Marvell Nanofab Process Manual

• BYU KOH processing

• UC Irvine KOH Etching

• U Alberta KOH Etching

Commercial Materials

• Transene Etch Compatibility Chart

• Transene Etchant List

• MicroChemicals trove of application notes

KNI Wet Etch Recipes Table

Material	Etchant	Rate (nm/min)	Anisotropy	Selective to	Selectivity	Origin and Notes
KNI CHA Al	Al Etch Type A	X	-	Al	Good	Matches Transene's expected rate
KNI CHA Al	Al Etch Type D	X	-	Al	High	Matches Transene's expected rate
KNI CHA Al2O3	Phosphoric Acid	X	-	-	-	Measured 11/19 by
KNI Tystar Furnace 1000°C SiO2	HF	111	Very Low	SiO2	High	Measured 11/19 by Alex Wertheim
KNI PECVD 350°C SiO2	HF	486	Low	SiO2	High	Measured 11/19 by Alex Wertheim
KNI PECVD 200°C SiO2	HF	1398	High	SiO2	High	Measured 11/19 by Alex Wertheim
KNI PECVD 350°C Si3N4	Phosphoric Acid	X	-	-	-	Measured 11/19 by
KNI PECVD a-Si	KOH	X	High	Si	High	Link here to KNI member's research paper

Other Procedures

Liftoff

• UCSB liftoff guidance

• Stanford SNF liftoff procedures

Electroplating

• Technic electroplating materials supplier

Safety Resources

• KNI Lab Rules & Safety

• BYU Acid Safety, HF Safety, Solvent Safety