Transene - Gold Etchants

Gold Etchants
for Microelectronics Circuits

Selective etchants for gold, compatible with negative and positive photoresists-used in thin film microelectronics to develop circuit elements.

Etching readily controlled with minimum undercutting — provides excellent definition.
Room-temperature operated.
Uniform etch rates
Economical
Gold Etchants TFA, GE-8148, GE-8110, and GE-8111 are available in glass or plastic packaging depending on shipment method

GOLD ETCHANT TFA and GOLD ETCHANT GE-8148

DESCRIPTION:

These thin film etchants are used to obtain selective etching of gold in the photo fabrication of microelectronic circuits. Used in conjunction with photoresist technology, these etchants form precise electrodes and resistor patterns in thin films prepared on alumina and other substrates.

High purity, low sodium and 0.2 micron filtration for semiconductor and microelectronics applications.

Gold Etchant TFA - Cyanide free for standard applications.
GE-8148 - Cyanide free, no attack of nickel films.

	TFA	GE-8148
Operating Temperature	Room Temperature	Room Temperature
Ventilation	Hood recommended	Hood recommended
Agitation	Work agitation; Speed accelerates etch rate	Work agitation; Speed accelerates etch rate
Tank	Glass, PVC, Quartz	Glass, PVC, Quartz
Etch Rate @ 25 °C	28Å/sec.	50Å/sec.
Composition	Ready -to - use liquid Contains KI-I₂ complex	Ready -to - use liquid Contains KI-I₂ complex - Phosphate compound
pH @ 20 °C		8.15 ± 0.2
Density @ 20 °C		1.265 ± 0.01
Etch Capacity g/gal	100	100
Resist Compatibility	Neg & Pos.	Neg. & Pos.
Rinse	Distilled, Dionized Water
Waste Disposal (Reclaim Gold in spent etchant.)	Dispose in accordance with all federal, state and local regulations. Send waste to an approved waste disposal facility.

Max. Impurity (ppm, Gold Etch TFA)

Sodium ( Na)	40
Chlorine & Bromides (Cl)	100
Lead (Pb)	5
Iron (Fe)	3
Sulfur (as sulfates)	50
Phosphorous (as phosphates in TFA)	10

GOLD ETCHANT
GE-8110
GE-8111

GE-8110 and GE-8111 Gold Etchants are etching solutions designed specifically for etching thin films of gold in the fabrication of semiconductor devices and thin film microelectronics. The solutions are based on potassium iodide and iodine ( KI/I₂) chemistry and do not contain cyanide. They are compatible with both positive and negative photoresist materials, giving controllable line definition. GE-8110 is buffered to approximately pH 8.0 while GE-8111 is acidic with a lower solids content and is a slower acting etching solution. Both etchants should be used at room temperature in a well-ventilated area.

Physical and Chemical Properties:

Appearance and odor: dark brown liquid with iodine vapor odor.

	GE-8110	GE-8111
pH (20 °C)	7.9 ± 0.1	2.5 ± 0.1
Density ( 20 °C)	1.33 ± 0.01	1.15 ± 0.01
Etch Rate ( 30 °C)	20Å/sec	30Å/sec

REAGENT GRADE CHEMICAL

IMPURITY	SPEC. PPM (MAX)
MAX-IMPURITY PPM
Sodium ( Na)	40
Chlorine & Bromides ( Cl)	100
Lead (Pb)	5
Iron (Fe)	3
Sulfur (as sulfates)	50

Storage and Handling

Store at room temperature away from sunlight. Keep container sealed when not in use. Iodine vapor can irritate the eyes severely. Open in ventilated areas. In case of contact with eyes or skin, wash with plenty of water (or soapy water for skin), and consult a physician if irritation persists.

GOLD ETCHANT TFAC
FOR INTERMETALLIC SUBSTRATES

DESCRIPTION:

Gold Etchant TFAC is a selective etchant for the preparation of microelectronic circuits on gallium arsenide, gallium phosphide, and other intermetallic semiconductor compounds. Gold Etchant TFAC provides excellent definition with minimal undercutting. Uniform etch rates are obtained with this cyanide based etchant. Gold Etchant TFAC strips gold from copper, brass, bronze, nickel, and other non-ferrous metals (except silver). Gold Etch TFAC is compatible with aluminum.

PROPERTIES:

Operating Temperature	Room Temperature
Ventilation	Hood
Agitation	Work agitation speed accelerates etch rate
Tank	Polypropylene
Etch Rate 60 ^oC	30 angstroms/second
Composition	Cyanide-containing powder. Dilute with water (8oz /gal) prior to use.
Etch Capacity @ 60 °C	90grams/gal
Rinse	Water
Disposal	See Below

APPLICATION:

Warm water to approximately 50 °C to aid dissolution. Add 8oz Gold Etchant TFAC powder per gallon deionized water. Etch the conductor pattern to remove gold; etch time depends on thickness. Spent etchant should be saved for gold reclamation.

Disposal: Segregate solution. Cyanide should be handled carefully and disposed of according to local and state regulations.