Supercritical Fluid Technology

JASCO's Supercritical CO2 Photo Resist Stripping and Wafer Cleaning System offers excellent performance as a cleaning solvent in the photoresist stripping/cleaning/drying processes due to unique properties such as low viscosity, high diffusivity, high permeability and no surface tension.

Please download the JASCO General Catalogue brochure

Features

System Description

The complexity of integrated circuits has been increasing as lithography technology improves. In order to achieve pattern widths in the sub-micrometer range, the method of photoresist stripping and cleaning of silicon wafers is critical.

In addition, the fluid becomes a gas when reducing the pressure to atmospheric at ambient temperature. A liquid solvent can often collapse microstructures with a high aspect ratio due to its high surface tension. On the other hand, supercritical CO2 has no liquid-gas phase boundary and no surface tension occurs, therefore, the fluid can penetrate into microstructures without damaging the lithography pattern.

Specifications

Perfluoropolyether lubricant preparative refinery system using the supercritical fluid extraction method

This preparative scale supercritical fluid extraction (SFE) system using carbon dioxide is equipped with a pump and back-pressure regulator to enable delivery of up to 150 ml/min of CO2, and is also equipped with a 1 liter extraction vessel.

1. CO₂
2. Modifier or washing solution
3. CO₂ Large volume solvent delivery pump (PU-2150; Max.150 mL/min)
4. Modifier delivery pump
5. Stop valve
6. Safety valve
7. Pre-heating coil
8. Extraction vessel (1000 mL)
9. Temperature control jacket
10. Temperature meter
11. Back pressure valve
12. 6-way switching valve
13. Pressure meter
14. Fraction vessel
15. Temperature controller

Perfluoropolyether (PFPE) is a lubricant widely used in many aerospace, vacuum, electronic and semiconductor applications due to its excellent chemical and tribological properties. It is typically used for friction reducing films on hard disks. In order to obtain a greater amount of functional PFPE, supercritical carbon dioxide extraction systems can refine and separate wide molecular weight distribution PFPE mixtures into a higher performance PFPE with a narrower molecular weight distribution.

GPC chromatograms of PFPE fractions (Z DOL-2000, Polydispersity: 1.78) extracted by this system

Average molecular weight and polydispersity (Mw/Mn) of PFPE fractions extracted by this system.

Fractions	Pressure (MPa)	Extraction Time (min)	Mw	Mn	d=Mw/Mn	weight (g)	%
Z DOL 2000	Starting Material	-	2128	1192	1.7844	203.95	-
1	11.0MPa	90	767	638	1.2030	25.49	12.5
2	12.0MPa	90	1141	888	1.2848	51.93	25.46
3	12.5MPa	40	1502	1194	1.2573	21.61	10.59
4	12.7MPa	40	1790	1459	1.2268	20.47	10.03
5	13.0MPa	40	2191	1832	1.1960	18.25	8.94
6	13.5MPa	40	2755	2321	1.1870	18.17	8.90
7	14.0MPa	40	3469	2914	1.1904	17.14	8.40
Residue		-	6714	5039	1.3324	27.48	12.47
Total						200.54	98.32