Multilayer printed wiring board and method for producing multilayer printed wiring board

A method for producing a multilayer printed wiring board, the method comprising:

• step of preparing a core substrate, a first prepreg, a second prepreg, a first metal foil, and a second metal foil,
• the core substrate having a first surface and a second surface, the core substrate including a conductor layer disposed at each of the first surface and the second surface, and a first glass cloth woven with first warp threads and first weft threads, the first warp threads each having a width narrower than a width of each of the first weft threads,
• the first prepreg including a second glass cloth woven with second warp threads and second weft threads, the second warp threads each having a width narrower than a width of each of the second weft threads,
• the second prepreg including a third glass cloth woven with third warp threads and third weft threads, the third warp threads each having a width narrower than a width of each of the third weft threads;
• step of heating and pressing the core substrate, the first prepreg, the first metal foil, the second prepreg, and the second metal foil which are stacked with each other,
• the first prepreg being stacked on the first surface of the core substrate to allow each of the first warp threads constituting the first glass cloth to be arranged perpendicular to each of the second warp threads constituting the second glass cloth,
• the first metal foil being further stacked on the first prepreg,
• the second prepreg being stacked on the second surface of the core substrate to allow each of the first warp threads constituting the first glass cloth to be arranged perpendicular to each of the third warp threads constituting the third glass cloth,
• the second metal foil being further stacked on the second prepreg;
• and
• step of processing the first metal foil to form a first conductor layer, and processing the second metal foil to form a second conductor layer, the first metal foil and the second metal foil lying at outermost surfaces of multilayer printed wiring board, respectively.