Method for manufacturing circuit devices

A method for manufacturing circuit devices comprising:

• preparing a laminated plate by laminating a first conductive film and a second conductive film via a third conductive film;
• forming a conductive wiring layer by etching said first conductive film into a desirable pattern;
• removing said third conductive film by use of said conductive wiring layer as a mask;
• covering front-surface portions of the second conductive film exposed by removing said third conductive film, said conductive wiring layer, and end faces of the third conductive film with an insulating layer;
• partially exposing said conductive wiring layer by removing a part of said insulating layer;
• fixedly fitting semiconductor elements onto said insulating layer and electrically connecting said semiconductor elements with said conductive wiring layer;
• covering said semiconductor elements with a sealing resin layer;
• and
• removing said second conductive film to expose said third conductive film on the rear surface.