METHOD OF RECYCLING ABRASIVE SLURRY

• US 20090053981A1
• Filed: 08/15/2008
• Published: 02/26/2009
• Est. Priority Date: 08/23/2007
• Status: Abandoned Application

• Current Assignee: Sumco Techxiv Corporation (Sumco Corporation)
• Original Assignee: Sumco Techxiv Corporation (Sumco Corporation)
• Inventors: Gotou, Isamu, Kozasa, Kazuaki
• Application Number:
  US12/192,351
• Publication Number:
  US 20090053981A1
• Time in Patent Office: Days
• US Class Current: 451/447
• CPC Class Codes: B24B 37/0056 taking regard of the pH-value of lapping agents
• CPC Class Codes: B24B 57/00 Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents for abrasive blasting B24C1/00, B24C7/00

Abstract

A method of recycling an abrasive slurry for recycling a slurry that: contains colloidal silica; and has been used in polishing semiconductor wafer(s) is provided. The method includes: adding a dispersant to the used slurry having been collected so as to prevent the used slurry from being gelled; irradiating ultrasound to the used slurry having been added with the dispersant so as to disperse a gelled portion and aggregated silica in the used slurry; and, by using a filter, removing a foreign substance contained in the used slurry having been irradiated with the ultrasound.

Claims

1. A method of recycling an abrasive slurry for recycling a slurry containing colloidal silica, the slurry being a used slurry having been used in polishing semiconductor wafer(s), the method comprising:

adding a dispersant to the used slurry having been collected so as to prevent the used slurry from being gelled;

irradiating ultrasound to the used slurry having been added with the dispersant so as to disperse a gelled portion and aggregated silica in the used slurry; and

removing a foreign substance contained in the used slurry having been irradiated with the ultrasound, the foreign substance being removed by a filter.

2. The method of recycling an abrasive slurry according to claim 1, wherein

a pH value of the used slurry is measured and the pH value is adjusted by adding an alkali solution before the dispersant is added to the used slurry.

3. The method of recycling an abrasive slurry according to claim 1, wherein

viscosity of the used slurry is measured and the viscosity is adjusted by adding a water-soluble polymer before the dispersant is added to the used slurry.

4. The method of recycling an abrasive slurry according to claim 1, wherein

a temperature of the used slurry is measured and the temperature is adjusted by using a heat exchanger before the dispersant is added to the used slurry.

5. The method of recycling an abrasive slurry according to claim 1, wherein

metal ion contained in the used slurry is removed after the ultrasound is irradiated to the used slurry.

6. The method of recycling an abrasive slurry according to claim 5, wherein

the metal ion contained in the used slurry is removed by adding a chelate agent to the used slurry.