Method of manufacturing printed wiring board

A method of manufacturing a printed circuit board comprising:

• forming a metal thin film on a substrate having a projection;
• providing an initial circuit pattern on said substrate by patterning the metal thin film, said initial circuit pattern comprising first and second circuit patterns isolated from each other and a conductive layer formed on the projection to make a temporary electrical connection between the first and second circuit patterns;
• performing electroplating by the passage of electric current through the initial circuit pattern to form an additional metal film on the initial circuit pattern;
• and
• after the electroplating, removing the conductive layer on the projection to provide electrical insulation between the first and second circuit patterns.

A method of producing a printed wiring board comprising the steps of:

• providing a substrate with a first surface having a first projection and a second surface extending at a different level from the first surface and having a second projection thereon;
• forming a first circuit pattern on the first surface;
• forming a second circuit pattern isolated from the first circuit pattern on the second surface;
• forming a third circuit pattern isolated from the first and second circuit patterns so as to extend from the first surface to the second surface;
• forming a first conductive layer on the first projection to make a temporary electrical connection between the first and third circuit patterns;
• forming a second conductive layer on the second projection to make a temporary electrical connection between the second and third circuit patterns;
• performing electroplating by the passage of electric current through the first, second and third circuit patterns connected by the first and second conductive layers to simultaneously form a metal film on the first, second and third circuit patterns;
• and
• after the electroplating, removing the first and second conductive layers on the first and second projections to provide electrical insulation among the first, second and third circuit patterns.