Abstract: In a multilayer wiring board comprising a substrate on which two or more layers of wiring or insulation film are formed of different materials, for example, the wiring layer is processed so that the processed side faces of the board contour a stepped shape in the cross-sectional view of the board, whereby coverage of a film formed thereon can be improved. Specifically, first, insulation film 2 is formed on a substrate 1 and then, resistor film 3 and resistor electrode film 4 are continuously formed thereon to form a film of multiple structure. Mask 9 is formed thereon. Then, the layers is etched successively in the order of from the top layer and thereafter only the resistor electrode film 4 is further etched with an etching solution which selectively etches only the resistor electrode film 4 to form a stepwise patterned side face. Finally, the mask is removed and wiring electrode film 5 is formed.

Abstract: An electronic part is produced by forming two metallic wiring films of different materials on a main substrate, where a first metallic wiring film is formed on the main substrate, a protective film is formed in desired regions on the main substrate and the first metallic wiring film, and a second metallic wiring film is formed on the first metallic wiring film. The thus produced electronic part has an insulating protective film between the first and second metallic wiring films. By the presence of the protective film the surface of the first metallic wiring film is protected from etching, corrosion or deterioration by an agent for patterning the second metallic wiring film.

Abstract: A cooling structure for cooling a multichip module for effectively removing heat generated from integrated circuit chips. A suction plate formed with minute grooves on one of its surfaces is disposed between each integrated circuit chip and an associated cooling block and is brought into contact at a grooved surface with the integrated circuit chip through a layer of a liquid such as silicone oil interposed therebetween, thereby producing negative hydrostatic pressure by capillary action of the minute grooves. The suction plate has a thickness small enough to be bent under influence of the negative hydrostatic pressure to follow a warping of the integrated circuit chip, so that the clearance between the opposing surfaces of the suction plate and the integrated circuit chip can be minimized.