Plasma Etching

plasma_etching

The application of plasma etching a material with gas plasma is a very unique process that converts a solid to a gas form for removal. Plasma etching can eliminate the need for chemical etching which is time consuming and uses volatile organic compounds (VOC) and other dangerous chemicals. Organic materials, inorganic materials, and polymers are easily etched with non corrosive oxygen plasma. More complex inorganic materials and metals are etched with CF4 plasma or plasma of a similar gas mixture.

Plasma Etching Functional Principles

Plasma etching is the process of converting a solid directly to a gas in a low pressure plasma system. This gas is then pumped out of the vacuum chamber at a controlled rate to optimize uniformity and other process parameters. The entire process of etching is performed without the material ever coming in contact with fluid.

plasma_eching_principle

Oxygen-Based Etching

The process of etching a polymer, organic substance or hydrocarbon based solid works well with an oxygen based plasma process.  This oxygen based plasma etchs these materials by combining the carbon and hydrogen in the molecular structure with oxygen from the plasma.  This produces CO and HO in combination with short molecular chains that remain in a gas state and are easily pumped out of the chamber as a gas.

Hydrogen-Based Etching

The process of plasma etching to reduce an oxide on the surface of a metal or in a bulk oxide state is etched with a hydrogen based gas or gas mixture.  Similarly, this plasma etching process uses the hydrogen to combine with the oxygen on the surface and produce HO and other variants of the bulk molecular structure into a gas that is pumped out of the vacuum system.

Argon-Based Etching

The process of plasma etching a surface using argon is a physical etching method versus the chemical etching method described above. In this method of plasma etching the energy of the heavy argon atom in the plasma is very high.  This high level of energy enables the individual argon atom to deliver more energy to the surface of the part breaking the molecular bonds of the surface material.  The result is, these surface material atoms or short molecular components, are etched or ejected into the plasma for removal. 

Corrosive Service Etching

The process of plasma etching a material with a robust molecular structure or complex composition like metals and chemically stable polymers is done with a corrosive gas based component.  This corrosive gas of choice often focuses on a fluorine based chemistry like CF4, SF6, or other similar gases. The addition of these kinds of corrosive components provide a method of converting additional chemistries into a gas state providing a method of plasma etching.

Reactive Ion Etching

Reactive ion etching (RIE) is a plasma etching process that adds a charge to the part being etched which induces a directional component to the etching process.  This directionality of the etch enables significantly smaller etch feature sizes which is commonly used in the semiconductor industry.  

eBook

Plasma Etching and Cleaning Strategy for Better Product Quality

Plasma Etching Industries & Uses

  • Semiconductors: Plasma etching is the primary method of producing switching gates, subtractive lithography of conductors and insulators in the semiconductor industry and oxide reduction of bond pads and lead frames in the packaging side of the business.
  • Medical Devices: Plasma etching enables the coating and joining of inert, biocompatible materials with low surface energy.
  • Painting Industry: Etching is used for paint and glue adhesion with high temperature resistant plastics; examples include PTFE, PFA, and FEP.

Popular Plasma Etching Systems

{id=1, name='Femto', order=0}

Femto Version 1

Control Cabinet:
W 310 mm H 330 mm D 420 mm

Chamber:
Ø 3.9 in, L 10.9 in

Chamber Volume:
2

Gas Supply:
1 gas channel via needle valve

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz or 2.45 GHz)

Control:
Semi-Automatic

{id=3, name='Nano', order=2}

Nano Version 4

Control Cabinet:
W 560 mm H 600 mm D 600 mm

Chamber:
Ø 10.5 in, L 16.5 in

Chamber Volume:
24

Gas Supply:
Mass flow controllers

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz or 2.45 GHz)

Control:
Touch Screen

{id=5, name='Special Tetra', order=4}

Special Tetra 15-LF-PC

Control Cabinet:
W 600 mm H 1700 mm D 800 mm

Chamber Volume:
15

Gas Supply:
Mass flow controllers

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz or 2.45 GHz)

Control:
PC

{id=5, name='Special Tetra', order=4}

Special Tetra 500-LF-PC

Control Cabinet:
W 600 mm H 2100 mm D 800 mm

Chamber Volume:
500

Gas Supply:
Mass flow controllers

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz or 2.45 GHz)

Control:
PC

{id=5, name='Special Tetra', order=4}

Special Tetra 8000-LF-PC

Control Cabinet:
W 600 mm H 2100 mm D 800 mm

Chamber Volume:
8000

Gas Supply:
Mass flow controllers

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz or 2.45 GHz)

Control:
PC

{id=7, name='Zepto', order=6}

Zepto Version 4

Control Cabinet:
W 425 mm H 185 mm D 450 mm

Chamber:
Ø 4.1 in, L 11.8 in

Chamber Volume:
2.6

Gas Supply:
Mass flow controllers

Generator:
1 pc. with 40 kHz
(optional: 13.56 MHz)

Control:
External PC

Workshop

Learn about a Plasma Processing Workshop