Closed loop concentration control system for chemical mechanical polishing slurry
US6721628B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 2000 |
| Grant date | Apr 13, 2004 |
| Priority date | — |
| Expiry date | Dec 5, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/12
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Polishing slurry is transported via piping to flow into the closed loop control system. First, the polishing slurry flows into the ultrasonic concentration detector. Original data of the polishing slurry that is determined by means of ultrasonic concentration detector is a fluid velocity at that time. This determined value can be converted into weight percent concentration at that time by memory data table. The converted data of weight percent concentration will be transmitted into program logic controller (PLC), and the data of liquid level volume in the distribution tank will be transmitted into program logic controller at present. The program logic controller will then analyze whether the quantity of oxidant is sufficient. If the quantity of oxidant does not reach the required criterion, the program logic controller will control the analog valve to transmit a supplementary quantity of oxidant into the distribution tank via the analog valve and piping.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.