A commercially available solvent, such as a stripping chemical and/or an organic solvent, is supported by supercritical CO2 to remove a resist, its residue, and/or an organic contaminant off the surface of a semiconductor wafer. Supercritical CO2 has a high solvency which increases with pressure. The supercritical CO2 permits a tremendous reduction in reaction time and amount of chemical utilized for the resist removal process. In a preferred embodiment, the wafer is exposed to the CO2 and chemical mixture in a process chamber heated to a temperature of 20 to 80° C. at a pressure of 1050 to 6000 psig for a period of 10 seconds to 15 minutes.

Removal of resist or residue from semiconductors using supercritical carbon dioxide

Increasing production and disposal of coal fly ash (CFA) is a matter of serious environment concern. However, CFA contains various beneficial metals and mineral matters whose demand is increasing in the industrialized world, while natural supplies are diminishing. Therefore, recovery of these potential resources from CFA can be an alternative way to save mineral resources, as well as to reduce the environmental burden of CFA disposal. There are numerous methods developed for the recovery of beneficial products from CFA. Based on the US patents and journal literatures, the present review describes the recovery status and technologies of major elements such as Al, Si, Fe and Ti, and trace elements such as V, Ga, Ge, Se, Li, Mo, U, Au, Ag, Pt groups and rare earth elements (REEs) and other beneficial products such as magnetic materials, cenospheres, and unburned carbon from CFA. It also highlights the recovery efficiency and drawbacks for their extraction, and suggests future research to develop satisfactory results in terms of selective recovery and purification.

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Recovery of metals and other beneficial products from coal fly ash: a sustainable approach for fly ash management

A method of removing a photoresist or a photoresist residue from a semiconductor substrate is disclosed. The semiconductor substrate with the photoresist or the photoresist residue on a surface of the semiconductor substrate is placed within a pressure chamber. The pressure chamber is then pressurized. Supercritical carbon dioxide and a stripper chemical are introduced to the pressure chamber. The supercritical carbon dioxide and the stripper chemical are maintained in contact with the photoresist or the photoresist residue until the photoresist or the photoresist residue is removed from the semiconductor substrate. The pressure chamber is then flushed and vented.

Removal of photoresist and photoresist residue from semiconductors using supercritical carbon dioxide process

A method of removing inorganic contamination (contamination 104 of FIGS. 2a-2b) from a layer (layer 102) overlying a substrate (substrate 100), the method comprising the steps of: removing the layer overlying the substrate with at least one removal agent; reacting the inorganic contamination with at least one conversion agent, thereby converting the inorganic contamination; removing the converted inorganic contamination by subjecting it to at least one solvent agent, the solvent agent included in a first supercritical fluid; and wherein the converted inorganic contamination is more highly soluble in the solvent agent than the inorganic contamination.

Method of removing inorganic contamination by chemical alteration and extraction in a supercritical fluid media

A method of removing photoresist and residue from a substrate begins by maintaining supercritical carbon dioxide, an amine, and a solvent in contact with the substrate so that the amine and the solvent at least partially dissolve the photoresist and the residue. Preferably, the amine is a tertiary amine. Preferably, the solvent is selected from the group consisting of DMSO, EC, NMP, acetyl acetone, BLO, acetic acid, DMAC, PC, and a mixture thereof. Next, the photoresist and the residue are removed from the vicinity of the substrate. Preferably, the method continues with a rinsing step in which the substrate is rinsed in the supercritical carbon dioxide and a rinse agent. Preferably, the rinse agent is selected from the group consisting of water, alcohol, a mixture thereof, and acetone. In an alternative embodiment, the amine and the solvent are replaced with an aqueous fluoride.

Removal of photoresist and residue from substrate using supercritical carbon dioxide process

A process for recovering silver, gallium and/or other trace metals from a fine grained industrial fly ash associated with a process for producing phosphorous, the fly ash having a silicate base and containing surface deposits of the trace metals as oxides, chlorides or the like, with the process being carried out by contacting the fly ash with AlCl 3 in an alkali halide melt to react the trace metals with the AlCl 3 to form compositions soluble in the melt and a residue containing the silicate and aluminum oxide or other aluminum precipitate, and separating the desired trace metal or metals from the melt by electrolysis or other separation techniques.

Milton Blander

Papers

Extraction of trace metals from fly ash