| Autor: |
Almanza-Workman, A. M., Raghavan, S., Sperline, R. P. |
| Zdroj: |
Langmuir; April 2000, Vol. 16 Issue: 8 p3636-3640, 5p |
| Abstrakt: |
Buffered hydrofluoric acid (BHF) solutions containing HF and NH4F are widely used in the manufacturing of silicon-based integrated circuits. The adsorption/desorption characteristics of a commercially available, high purity, polyglycidol type surfactant (OHS) onto/from silicon from buffered hydrofluoric acid (BHF) solutions was studied by in situ attenuated total reflection−Fourier transform infrared spectroscopy (ATR−FTIR). The challenge in these measurements was to resolve the C−H peaks, in the 2800−3000 cm-1 region of the surfactant spectrum, that were masked by the strong absorbance due to N−H caused by a large amount of NH4+ ions in the solution. A technique has been developed to overcome this limitation. The principle of this technique is to carry out the surfactant adsorption in BHF solutions followed by the replacement of NH4+ ions by alkali-metal cations, such as K+ and Cs+, to allow better resolution of the C−H peaks from the baseline. Extrapolation of the adsorption density to time zero yields the adsorption density in the presence of NH4+. Using this technique, the adsorption density of OHS surfactant in a buffered HF solution containing 7 parts of NH4F (40%) and 1 part of HF (49%) was found to be approximately 20% higher than that in dilute HF solutions. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
