Differences

This shows you the differences between two versions of the page.

--- chemical:start [2012/01/29 08:46] – created mcmaster
+++ chemical:start [2013/10/20 14:59] (current) – external edit 127.0.0.1
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 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: [[chemical: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 =====
+TMAH poisoning study
+https://snf.stanford.edu/SNF/materials-and-chemicals/msds-std-chemicals/liquid/tetramethylammonium-hydroxide-tmah/TMAH.PDF/at_download/file
+====== Water (deionized (DI)) ======
+General cleaning
+====== References ======
+  - Isotropic Silicon Etching using HF/Nitric/Acetic Acid (HNA): http://engineering.tufts.edu/microfab/index_files/SOP/SiliconEtch_HNA_SOP.pdf
+====== Safety======
+===== Hydrofluoric acid =====
+  * MSDS: http://msds.dupont.com/msds/pdfs/EN/PEN_09004a2f801b4efc.pdf
+  * Health: 4
+  * Flammability: 0
+  * Instability/reactivity: 2
+  * Other: corrosive
+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.
+{{gallery>image:HF_gas_mask.jpg}}
+===== Nitric acid =====
+  * MSDS: http://www.jtbaker.com/msds/englishhtml/n3660.htm
+  * Health: 4
+  * Flammability: 0
+  * Instability/reactivity: 0
+  * Other: oxidizer
+  * Causes severe burns.
+===== Sulphuric acid =====
+  * MSDS: http://www.jtbaker.com/msds/englishhtml/s8234.htm
+  * Health: 3
+  * Flammability: 0
+  * Instability/reactivity: 2
+  * Other: reactive to water
+  * Causes severe burns.
+===== Hydrogen peroxide =====
+  * MSDS: http://www.jtbaker.com/msds/englishhtml/h4065.htm
+  * Health: 3
+  * Flammability: 0
+  * Instability/reactivity: 2
+  * Other: oxidizer
+  * Strong oxidizer. Even low concentrations can be dangerous when mixed with certain chemicals.
+====== References ======
+  - http://en.wikipedia.org/wiki/Hydrofluoric_acid
+  - http://en.wikipedia.org/wiki/Nitric_acid
+  - http://en.wikipedia.org/wiki/Sulfuric_acid
+  - http://en.wikipedia.org/wiki/Hydrogen_peroxide