PURPOSE: To obtain the semiconductor device having a high humidity resistance by a method wherein a polymer comprising a repeating structural unit expressed by the specified general formulas is spread and is printed to form a protective coating on a surface of the semiconductor element which is sealed by use of a resin composition or ceramic after that.
CONSTITUTION: The solution of a polymer comprising a repeating structural unit expressed by the general formulas ( I )W(III) (wherein R1 and R2 express the same or the different hydrocarbon radicals of one valency) is spread on surfaces of a semiconductor element 2, a lead wire 1 and so on. Next, a printing treatment is performed by heating with 100°C or over, more preferably with 150W 300°C. By this treatment, the polymer increases the molecular weight and crosslinking occurs to form a protective coating layer. The coating layer should be formed preferably so as to have a thickness of 10μm or less, more particularly of 1μm or less for obtaining good effects. This is attained by adjusting the concentration of the solution properly under 5wt% usually. Subsequently, the object composed of the element 2 and the lead wire 1 comprising a protective coating layer 3 is sealed, e.g. with an epoxy resin composition 6, thereby offering the semiconductor device.
SUGAWARA YASUHIDE
KANESHIRO TOKUYUKI
