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chemical:start

Relevant info on misc chemicals you might encounter. The goal of this page is not to present a comprehensive list of chemicals but rather to highlight some useful chemicals and some key points.

Different chemicals and why you might want them

Acetic acid

Delayering: component of standard wet etch. Used as a dillutant in preference over H2O, so vinegar isn't of much use.

Acetone ((CH3)2CO)

General cleaning

Ammonium fluoride (NH4F)

Delayering: buffered oxide etching (BOE) buffer salt

Chromium trioxide (CrO3)

Delayering: component of various wet etch solutions

Copper nitrate (Cu(HNO3)2)

Delayering: Wright etch

Hydrochloric acid (HCl)

Delayering: reduces insoluble products in buffered oxide etching (BOE)

Hydrofluoric acid (HF)

Delayering: component of all wet etches Can be stored in polymethylpentene (PMP), polyethylene (PE), and Teflon (PTFE). [Isotropic Silicon Etching using HF/Nitric/Acetic Acid (HNA)]

HF is notably toxic

See HF for more details

Isopropanol (Isopropyl alcohol (IPA))

General cleaning

Nitric acid (HNO3)

Decapsulation. Info on making: hno3

Potassium dichromate (K2Cr2O7)

Delayering: Secco etch

Sulphuric acid (H2SO4, 98%)

Decapsulation: usually bare die, especially for tough epoxies

Tetramethylammonium hydroxide (TMAH)

Silicon etchant, maybe useful for delayering

Health

Water (deionized (DI))

General cleaning

References

  1. Isotropic Silicon Etching using HF/Nitric/Acetic Acid (HNA): http://engineering.tufts.edu/microfab/index_files/SOP/SiliconEtch_HNA_SOP.pdf

Safety

Hydrofluoric acid

WARNING: probably the most dangerous chemical you might encounter for this work. Suggest use of fully body protection including gloves, acid gas respirator, and frontal protection. Contact can include causing excruciating pain from dissolving bones, severe burns, cardiac arrest, and more. It may be useful to keep calcium gluconate (2.5% gel) handy to increase chance of survival in case of contact. Seek IMMEDIATE medical attention. It is unknown how over the counter HF from Whink rust remover compares to concentrate in terms of necessary safety precautions.

Nitric acid

Sulphuric acid

Hydrogen peroxide

References

chemical/start.txt · Last modified: 2013/10/20 10:59 (external edit)