Removing material from solids, especially semiconductor wafers, employs liquid jet containing e.g. halogen compound which is irradiated to produce highly-reactive free radicals

摘要

An etchant capable of being activated, is added to the liquid jet (1). It is activated after leaving the nozzle which produces the jet. Activation is effected by irradiation using an annular radiation source (3) close to the jet. Irradiation is at right angles to the jet. A reflective surface (2, 2') at least part-surrounds the jet. Photo- and/or thermochemical activation takes place. Irradiation takes place in the W band of electromagnetic radiation, resulting in photochemical activation. Alternatively, infra red radiation promotes thermochemical activation. In a further variant, the visible waveband is used, causing photochemical activation. The light is incoherent and continuous, or it is pulsed. Ultraviolet light is provided by e.g. a mercury lamp, photodiode and/or a flash lamp. In addition, the location on the solid where the jet impinges, is irradiated using one of the above methods. The etchant is a water-free halogen- containing organic or inorganic compound or mixture. It is a straight chain, branched, aliphatic, cycloaliphatic and/or aromatic C1-C12 hydrocarbon which is at least partially halogenated. It is e.g. carbon tetrachloride, chloroform, bromoform, dichloromethane or a mixture of them. A wide range of further examples is specified in accordance with these principles, including diverse sulfur-, phosphorous- and ammonium compounds. Lewis-acids may be employed, especially boron trichloride or aluminum trichloride. The etchant includes at least one radical initiator, e.g. dibenzoyl peroxide or azo-isobutyronitrile. A radiation absorber is included, e.g. a dye, especially eosin, fluoroscene, phenolphthalein and/or Bengal red. It is alternatively a polycyclic aromatic compound, especially pyrene or napthacene. A solid body of silicon is used. An independent claim IS INCLUDED FOR corresponding apparatus.