Abstract: A method for manufacturing a semiconductor device comprising a nonvolatile memory transistor of a stacked gate structure having a floating gate and a control gate, and a MOS transistor of a single gate structure, wherein the method comprises the steps of forming a first insulation film that becomes a gate oxide film of the transistors on a semiconductor substrate; forming a first conductive layer on the first insulation film; removing, from the first conductive layer, a region for separating a floating gate in a direction perpendicular to a direction in which the control gate is formed extendedly; forming a second insulation layer on the first conductive layer; forming a second conductive layer on the second insulation film; patterning the second conductive layer so as to form the control gate; and patterning the first conductive layer to form the stacked gate structure and the single gate structure.

Abstract: A process for producing a polyether polyol with a content of 0.5 to 99.5% by weight of oxytetramethylene groups derived from tetrahydrofuran by copolymerizing tetrahydrofuran or a mixture of tetrahydrofuran and other cyclic ether copolymerizable therewith with a polyhydric alcohol having two or more hydroxyl groups per one molecule with the use of a heteropoly-acid and/or its salt as a catalyst, which comprises allowing 0.1 to 15 molecules of water per one heteropoly-anion to exist in the catalyst phase.The above-described polyether polyol is an industrially useful polymer which is a starting material for polyurethane to be used for spandex or a synthetic leather, etc.

Abstract: A process for producing a polyether polyol with a content of 0.5 to 99.5% by weight of oxytetramethylene groups derived from tetrahydrofuran by copolymerizing tetrahydrofuran or a mixture of tetrahydrofuran and another cyclic ether copolymerizable therewith with a polyhydric alcohol having two or more hydroxyl groups per one molecule with the use of a heteropoly-acid and/or its salt as a catalyst, which comprises allowing 0.1 to 15 molecules of water per one heteropoly-anion to exist in the catalyst phase.The above-described polyether polyol is an industrially useful polymer which is a starting material for polyurethane to be used for spandex or a synthetic leather, etc.