Patent ID: 7881071
Filing Date: 2011-02-01
Classification: H01L,H05K,Y10T

Abstract:
1. A multilayer printed wiring board comprising: a plurality of insulating layers having an outermost insulating layer; conductor patterns disposed on an upper surface of the outermost insulating layer; a low elastic modulus layer formed on the outermost insulating layer and the conductor patterns; mounting electrodes disposed on an upper surface of the low elastic modulus layer, for mounting an electronic element; and a plurality of conductor posts passing through the low elastic modulus layer and electrically connecting the mounting electrodes and the conductor patterns, and having external conductor posts positioning at external portions among the conductor posts and internal conductor posts positioning at internal portions among the conductor posts, wherein the Young's modulus at 30° C. of the low elastic modulus layer is 10 MPa to 1 GPa, and the conductor posts have an aspect ratio Rasp which is not less than 4 and a diameter which is larger than 30 km, and the aspect ratio Rasp of the external conductor posts is greater than or equal to the aspect ratio Rasp of the internal conductor posts.