Liquid concentration detecting apparatus
US5903006A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 1997 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | May 27, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/3577
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A liquid concentration detecting apparatus which permits a real-time and high-accuracy detection of concentration of a liquid (particularly an etching or cleaning solution) used in a semiconductor plant, with a simple configuration at a low cost. The liquid concentration detecting apparatus 1 has a cell 2 to which a liquid is supplied, and a projecting section 4 and a receiving section 5 arranged opposite to each other in a direction at right angles to the axial line of the cell. A light of a prescribed wavelength is projected from this projecting section 4 through the liquid in the cell 2 to the receiving section 5, and the concentration of the liquid is determined by detecting the amount of light received by the receiving section. The cell 2 has a plate-shaped spacer 6 having a slender hole 9 formed therein, and at least within a detecting section 3 region where the projecting section 4 and the receiving section 5 are arranged opposite to each other, the cell is configured to be substantially in close contact with the both surfaces of the spacer 6, whereby the liquid supplied to the cell flows in the slender hole 9 formed in the spacer 6 within the detecting section 3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.