Apparatus for continuously controlling the peroxide and ammonia concentration in a bath
US5578273A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 1995 |
| Grant date | Nov 26, 1996 |
| Priority date | — |
| Expiry date | Aug 18, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/02052
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for cleaning substrates in a process for device fabrication is disclosed. An aqueous solution of hydrogen peroxide and ammonium hydroxide is used to clean the substrates. The concentration of hydrogen peroxide and ammonium hydroxide in the cleaning solution is maintained at a certain level. The life of the cleaning solution is extended by the process. By maintaining the concentrations of the hydrogen peroxide and ammonium hydroxide in the solution within a desired range, the process also provides a cleaning solution that effectively cleans the substates throughout the entire time the solution is used to clean the substrates. The apparatus monitors certain solution parameters such as the pH and the conductivity of the cleaning solution and adds hydrogen peroxide and/or ammonium hydroxide to the cleaning solution to maintain the parameters, and thus the concentration of hydrogen peroxide and ammonium hydroxide, at desired levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.