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Sigma-Aldrich

Tungsten etchant

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Synonym(s):
Tungsten etch
MDL number:
MFCD08705365
UNSPSC Code:
12352300
NACRES:
NA.23

Quality Level

100

Related Categories

General description

Tungsten etchant is a mixture of potassium hydroxide and potassium ferricyanide based solution that facilitates the removal of tungsten and other materials like aluminium by dipping the substrate into the etching solution.

Application

Selective etchants for tungsten thin-film metallizations used in semiconductor and microelectronics technology. Etchants are buffered, mildly alkaline ferricyanide-based formulations providing high resolution patterns with minimal undercutting and photoresist compatibility. Etchant is ready to use (no dilution required). Controlled, uniform etching is achieved by immersion or spray etch technique. Etch Capacity (rate declines at ∼70%) of 64 g/gallon. Recommended Operating Temperatures: 20-80 °C (30-40 °C most common).

Preparation Note

1. Select your etching method according to the table belowEtch Rate (Immersion) Etch Rate (Spray)
  • 20°C = 30 Å/second
  • 30°C = 140 Å/second 20°C = 80 Å/second
  • 60°C = 250 Å/second

2. Rinse with DI water

Pictograms

Corrosion
GHS05

Signal Word

Danger

Hazard Statements

H290,H314,H412

Hazard Classifications

Aquatic Chronic 3 - Eye Dam. 1 - Met. Corr. 1 - Skin Corr. 1A

Supplementary Hazards

EUH032

WGK

WGK 2

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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  1. How do I increase the etch rate?

    1.The rate will approximately double with every 10°C increase in temperature. 2. Increase the rate of stirring or agitation.

  2. How do I reduce the etch rate?

    Adding 1-part deionized water to 2 parts etchant will reduce the etch rate approximately 50%.

  3. Do I need to dilute the etchant?

    No, it is ready to use.

  4. How do I reduce undercutting?

    Increase the rate of stirring or agitation.

Pattern processing results and characteristics for SCALPEL masks.
Novembre AE, et al.
Microelectronic Engineering, 46(1-4), 271-274 (1999)
Electrostatically actuated copper-blade microrelays.
Lee H, et al.
Sensors and actuators A, Physical, 100(1), 105-113 (2002)
Microstructure Evolution of W-Cu Alloy Wire.
Shao F, et al.
Materials Sciences and Applications, 3(03), 157-157 (2012)

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