Method for manufacturing printed wiring board

A method for manufacturing a printed wiring board, comprising:

• forming on a support sheet an intermediate body comprising a first insulation layer, a second insulation layer and a first conductive layer interposed between the first insulation layer and the second insulation layer;
• separating the support sheet from the intermediate body comprising the first insulation layer, the first conductive layer and the second insulation layer such that the intermediate body is detached from the support sheet;
• forming a first opening portion in the first insulation layer such that the first opening portion penetrates through the first insulation layer and reaches the first conductive layer;
• forming a second opening portion in the second insulation layer such that the second opening portion penetrates through the second insulation layer and reaches the first conductive layer;
• forming a second conductive layer on the first insulation layer;
• forming a third conductive layer on the second insulation layer;
• forming a first via conductor in the first opening portion such that the first via conductor connects the first conductive layer and the second conductive layer;
• and
• forming a second via conductor in the second opening portion such that the second via conductor connects the first conductive layer and the third conductive layer,
• wherein the forming of the intermediate body includes forming the first insulation layer on the support sheet, forming the first conductive layer on the first insulation layer, and forming the second insulation layer on the first insulation layer and the first conductive layer such that the intermediate body comprising the first insulation layer, the second insulation layer and the first conductive layer interposed between the first insulation layer and the second insulation layer is formed.