IC
Ion Chromatography
Ion Chromatography is a technology for measuring positive/negative ion and organic acid contained in liquid. After separating
the eluting solvent by means of separation column filled with ion exchanging resin of low- exchange-capacity, electric conductivity
is reduced by means of suppressor to measure amount of positive/negative ion and organic acid with conductometric detector.
With high speed and sensitivity/accuracy (a few 10ppb level) performance, multiple ions can be quantitatively/qualitatively
analyzed with small number of specimen.
This technology is especially suitable for measuring trace inorganic ion kinds, alkali metal, metal of the alkaline earth,
or ammonium ion.
The technology is generally used in analyzing stream and rain water, plating solvent constituent, ion analysis on extracted
liquid of electron material kinds or rinse water for semiconductor.
Equipment
Ion Chromatography Analyzer
Model: IC7000 Suppressor type
Specifications: Electric conductivity detection type, 0-5ms/cm
Sensitivity: several ppb - dozen ppb
Example
Cause analysis for mitsed optical reflection mirror
Inorganic negative ion data was captured through cause analysis for misted optical reflection mirror.
The mechanism was identified as; reaction between air and activated ozone togather with high voltage condition formed nitric
ion which was then adsorbed on the mirror surface in form of mist.
Quantitative /Qualitative analysis result
| No. | Element | Duration(min) | Density(ppm) |
|---|---|---|---|
| 1 | F | 2.71 | 0.18 |
| 2 | Cl | 3.51 | 0.39 |
| 3 | NO3 | 5.54 | 4.90 |
| 4 | SO4 | 9.44 | 0.58 |
| 5 | Unknown | 11.35 | Unknown |
Corrosion in electrode due to residual chlorine ion on silicone resin
Silicon resin coating that hardened under ambient temperature is used for the purpose of electric insulation, moisture/water/dust
prevention in Hybrid IC and PCB, etc.
There is a type of silicone resin that contain great amount of residual chlorosilane. Applying relevant silicone resin invites
corrosion failure in component electrode caused by hydrogen chloride; hydrolyzed residual chlorosilane.
Corrosion in metallic electrode
Following table shows the result of Ion chromatograph analysis of ion contained in defective silicone resin.
(Unit: ppm)
| Silicone resin | Detected ion | ||||
|---|---|---|---|---|---|
| HCOO | Cl | NO2 | NO3 | SO4 | |
| NG resin | 0.05 | 0.13 | 0.04 | 0.06 | 0.02 |
| Improved resin | 0.04 | 0.01> | 0.03 | 0.01> | 0.01 |