High frequency module device and method for its preparation

A high frequency module device comprising:

• a base substrate including a core substrate formed of an organic material having thermal resistance and high frequency characteristics, a pattern wiring layer formed on a first major surface of said core substrate in which an uppermost layer of said pattern wiring layer is planarized to form a high frequency device layer forming surface, and a number of copper foil layers each affixed to a resin layer to form a resin-coated copper foil layer located adjacent to said core substrate;
• and
• a high frequency device layer portion formed on said high frequency device layer forming surface of said base substrate;
• wherein passive elements are formed in the high frequency device layer portion by a thin film forming technique or by a thick film forming technique, said passive elements including resistors, capacitors and pattern wiring portions supplied with power or signals from said base substrate through a dielectric insulating layer;
• wherein said pattern wiring layer is formed on the dielectric insulating layer formed as the uppermost layer of said high frequency device layer, wherein a coating layer is formed by exposing a preset land of said pattern wiring and wherein at least one high frequency IC device directly connected to said land is directly loaded on said coating layer.