Patent ID: 11525073

Abstract:
There is a method of manufacturing a multilayer wiring board including: alternately stacking wiring layers and insulating layers; stacking a reinforcing sheet on one surface of the resulting multilayer laminate with a soluble adhesive layer therebetween, wherein an unoccupied region without the soluble adhesive layer is provided within a facing area where the reinforcing sheet faces the multilayer laminate; allowing a liquid capable of dissolving the soluble adhesive layer to infiltrate the unoccupied region to dissolve or soften the soluble adhesive layer; and releasing the reinforcing sheet from the multilayer laminate at the soluble adhesive layer. This method enables the multilayer wiring layer to be reinforced to generate no large local warpage, thereby improving the reliable connection and the surface flatness (coplanarity) of the multilayer wiring layer. The used reinforcing sheet can be released in a significantly short time, while minimizing the stress applied to the multilayer laminate.