.jpg)
Process Description
Integrated circuits on semiconductor chips are created through oxidation, etching, expansion and various other methods to create a series of circuit diodes, transistors and other electronic components, completing a particular functional logic (AND, OR, NAND, etc) to achieve a required circuit function. Semiconductor production has high process requirements, encompassing lithography, precision cutting, grinding and other complex processes. These production processes produces large amounts of waste water with various types of pollutants such as complex chemicals, heavy metals, organic pollutants, silicon and fluorine traces. Semiconductor process cooling water (PCW) applications would require filtration of the PCW before reusing (see water treatment applications).
Cleaning Process for Various Wastewater Sources
|
Application
|
Cleaning Medium
|
Equipment
|
Cleaning Effect
|
|
Photolytic Stripping
|
Oxygenated Plasma
|
Plate Reactor
|
Removes adhesives
|
|
Polymer Removal
|
H₂SO₄: H₂O = 6:1
|
Mixing Tank
|
Removes organic compounds
|
|
Natural Oxide Removal
|
HF : H₂O < 1:50
|
Mixing Tank
|
Creates anaerobic system
|
|
Rotary Drying
|
N₂Gas
|
Dryer
|
Does not produce residues
|
|
RCA-1 (Alkaline)
|
NH₄OH : H₂O₂: H₂O
= 1: 1: 1.5
|
Mixing Tank
|
Removes surface particles
|
|
RCA-2 ( Alkaline)
|
HCl: H₂O₂: H₂O
= 1: 1: 5
|
Mixing Tank
|
Removes heavy metals
|
|
DI Cleaning
|
Deionized Water
|
Mixing Tank
|
Removes cleaning solvents
|
Problems
• Volume of wastewater generated.
• Complex wastewater composition, with a variety of transition metals and contaminants such as:
• Silicon
• Germanium
• High content of fluorine
• Complex wastewater with high concentration of COD.
Applicable Products
• Ceramic Membrane Filtration System
• Small footprint
• Centralised management
• Intelligent control
• High outlet water quality
• Phosphate and COD removed from wastewater
• Resistant to acidic chemicals
• Long lifespan
• Easy maintenance
• Simplifies process without addition of reagents
