Apparatus and method for maintaining a uniform etching solution composition
US4710261A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 1987 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Jan 28, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32134
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An apparatus and method are disclosed for replenishing the depleted component of a multicomponent etching solution. A portion of the etching solution is analyzed with a UV detector to determine the concentration of the depleted component. An output signal is produced by the UV detector which is a function of the depleted component's concentration. In response to this output signal, a microprocessor is used to control the amount of make-up solution, enriched with the depleted component of the multicomponent etching solution, which is added to the etching solution. With the use of this system, a substantially uniform etch bath composition is maintained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.