Disclosed is a semiconductor device including a Si body, and SiO.sub.2 layer disposed on the surface of the body, an aluminum oxide layer having a thickness of about 50 A on the SiO.sub.2 layer, which is formed by applying a solution including an aluminum chelate compound onto the SiO.sub.2 layer and heating the solution at a temperature of 300.degree. C. for 30 minutes, and a polymer resin layer of polyimide disposed on the aluminum oxide layer. In this device, the adhesive-strength between the SiO.sub.2 layer and the polyimide layer is remarkably increased when compared with a semiconductor device wherein the polyimide layer is directly disposed on the SiO.sub.2 layer.