Abstract: Provided is a method of treating a wafer in the state where the wafer is fixed on a support plate with an adhesive composition. Although the wafer is treated by a chemical, heating, or exothermic treatment, the method achieves sufficient adhesiveness during the step of treating a surface of the wafer and allows detachment of the support plate from the wafer without damaging the wafer or leaving the adhesive on the wafer after the wafer treating step. The method of treating a wafer of the present invention includes the steps of: fixing a wafer on a support plate via an adhesive composition containing a curable adhesive component to be crosslinked and cured by light irradiation or heating; crosslinking and curing the curable adhesive component by light irradiation or heating of the adhesive composition; treating a surface of the wafer fixed on the support plate by a chemical, heating, or exothermic treatment; and detaching the support plate from the treated wafer.

Abstract: Provided is a method of treating a wafer in the state where the wafer is fixed on a support plate with an adhesive composition. Although the wafer is treated by a chemical, heating, or exothermic treatment, the method achieves sufficient adhesiveness during the step of treating a surface of the wafer and allows detachment of the support plate from the wafer without damaging the wafer or leaving the adhesive on the wafer after the wafer treating step. The method of treating a wafer of the present invention includes the steps of: fixing a wafer on a support plate via an adhesive composition containing a curable adhesive component to be crosslinked and cured by light irradiation or heating; crosslinking and curing the curable adhesive component by light irradiation or heating of the adhesive composition; treating a surface of the wafer fixed on the support plate by a chemical, heating, or exothermic treatment; and detaching the support plate from the treated wafer.

Abstract: A method for producing pitch and coke which comprises heating a starting oil material in the presence of a powdery carbonaceous substance at a temperature of 350.degree. to 600.degree. C under an increased pressure of at least 2 kg/cm.sup.2 gauge to produce pitch, coke and oil and separating the pitch and coke from the oil, said starting oil material being distillation residue of crude oil having a Conradson carbon residue of 1 to 25 weight percent and containing 20 to 80 weight percent of substances boiling at a temperature of at least 600.degree. C and less than 10 weight percent of substances boiling at a temperature lower than 350.degree. C, said powdery carbonaceous substance having a Conradson carbon residue of at least 50 weight percent and being added to the starting oil material in such an amount that Conradson carbon residue of the carbonaceous material is in the range of one-tenth to ten times that of the starting oil material.