Updated: July 2002

1. Equipment overview

This equipment regenerates pure water from the grinding and cutting waste water generated by semiconductor manufacturing processes and produces recycled material from the collected waste.
The waste water contains small silicon particles, 0.1 -0.5µm, which form a colloidal suspension.
This equipment employs a precision filtering separator for removing silicon particles in colloidal suspension and collecting pure water.
The silicon particles condensed by the filter are dried and solidified in a rotary dryer to regenerate high-purity silicon powder.

2. Features

a. Submerged flat membrane type separator
1) Reduced power consumption
Use of a submerged flat membrane type separator employed for the separating unit reduces electricity costs to thirty percent of those for a conventional pump circulating type system.
2) Longer membrane life
Use of a submerged flat membrane type separator also substantially reduces membrane wear by silicon particles, which is an inherent problem with pump circulating systems.

b. Dryer
1) Compact equipment
Instead of using a rotary drum type dryer, a rotary multi-disc type dryer enables reduction of installation space to 2/3 of that of a conventional model.
2) Energy saving
In combination with a factory co-generation system, low-cost steam can be used to effectively utilize excess steam.

3. Performance

a. Processing objects
Waste water from semiconductor wafer grinding and cutting
b. Processing capacity
10 m³/hr, 240 m³/day
(Equipment can be built from 0.5 m³/hr capacity)
c. Processing performance
1) Filtered water SDI < 4
2) Solid Water < 15%

4. Applicable fields and treatable materials

- Waste water from semiconductor wafer grinding and cutting
- Waste water from glass lens grinding
- Other waste water from grinding