As we are getting advance in technology and we want our products to be more efficient and more reliable, we need to keep advancing in technology further more. When it comes to semiconductor devices and components we have to be at best for the better result, and so we need to avoid using chemicals for the applications like etching, cleaning etc. and now a days plasma is the best substitute for chemicals for the application of etching and cleaning. Furthermore we can use the plasma for the substrate activation and for the deposition technology as well.
So……..What is Plasma???
When energy is continuously supplied to a matter, the temperature of the matter increases and it passes from solid state to liquid and finally to gaseous state. If the energy supply continues, the existing atomic shell disintegrates and charged particles are created (negatively charged electrons and positively charged ions). This mixture is referred to as plasma or the “fourth state of matter”.
Solid ⇒ liquid ⇒ gaseous ⇒ plasma
Natural plasma occurs for example in lightning, polar lights, flames, and the sun. Artificially created plasma is found in neon tubes, welding processes and in flash bulbs, among others.
Now a days Plasma System Application is not confined in the semiconductor industry only, plasma systems are being used in the medical industries, automotive industries as well as in Aerospace and Defense industry as well.
What is the main application of the Plasma System…….???
- Cleaning – Ultra-fine contaminations not visible to the naked eye are found on all surfaces. Almost always, these contaminations must be removed as a prerequisite for faultless further surface treatment such as: gluing | printing | painting | bonding | coating | etching.
Advantages of Plasma Cleaning…..
- Cleans even in the smallest cracks and gaps.
- Cleans all component surfaces in one work step, including the interior of hollow bodies.
- Residue-free removal of breakdown products by vacuum extraction.
- No damage to solvent-sensitive surfaces by chemical cleaning agents.
- Removal also of molecularity fine residues.
- Very low process costs.
- Activation- Good wettability is a prerequisite for the adhesion of binding partners in painting, gluing, printing or bonding. Wetting is not only impaired by contamination with oil and grease; many materials have surfaces which, even if clean, cannot be sufficiently wetted by many liquids such as adhesives and paints. The liquid rolls off. Also after curing or drying, it will not adhere to the surface. Using Plasma we can activate-
- Ultra-high molecular weight polyethylene.
- Etching- Plasma etching is the removal of material from surfaces via plasma processes. It is also described as dry etching because conventional etching processes are carried out with wet chemical methods using aggressive acids. The plasma of the process gases change the aggregate state of the material to be etched from solid to gaseous, and the vacuum pump extracts the gaseous products.
Plasma Etching can be further classified as following.
Ion Etching- Argon or other noble gases which form ions but no radicals are used as processes gases. The etching effect is based on the knocking out of atoms or molecules from the substrate by the kinetic energy of the electrons accelerated in the electric field.
- Micro-structuring of surfaces e.g. for adhesion improvement (“micro sandblasting”).
- Bombarding of a vapour deposition source (“sputtering”).
Chemical Plasma Etching– Process gases are used whose molecules in the plasma are mostly broken down into radicals. In this the etching effect is isotropic, means it has same effect throughout.
- Decomposition of oxide layers.
- Removal of photoresist (“stripping”).
- Ashing of matrices for analysis.
- Etching of PTFE.
- Structuring and micro structuring of semiconductors.
Reactive Ion Etching- This is used primarily in semiconductor etching.
- Plasma Coating- We can deposit various type of coating use plasma techniques. Benefits of Plasma coating is as follows
- Extremely thin coats in the Nano meter range are possible.
- Constant process suitable for series production is possible due to complete automation.
- Wide range of variants is possible.
- Deposition can be done at low temperature.
- Chemical free deposition, no solvents required.