Multilayer Wiring Substrate and Method of Manufacturing the Same

A method of manufacturing a multilayer wiring substrate having:

• a stacked configuration multilayered by alternately stacking a plurality of resin insulating layers formed with a same material as a main element and a plurality of conductor layers;
• a plurality of first principal surface side connection terminals arranged on a first principal surface of the stacked configuration;
• a plurality of a second principal surface side connection terminals arranged on a second principal surface of the stacked configuration;
• and the plurality of conductor layers arranged in the plurality of resin insulating layers, and connected by a via conductor that becomes expanded in diameter along a direction of facing the first principal surface or the second principal surface ;
• the method comprising:
• a base preparing process that prepares a base on which stacking metal foils are stacked in a peelable state;
• a buildup process that alternately stacks the plurality of conductor layers and the plurality of resin insulating layers on the stacking metal foils to thereby form the stacked configuration and in which a coating metal foil is coated on a most outer surface of an uppermost outer layer thereof;
• an opening forming process that forms, after the buildup process, an opening in a resin insulating layer of the uppermost outer layer, thereby exposing a conductor layer corresponding to a lower terminal part of the first principal surface side connection terminal;
• a terminal forming process that partly etches, after the buildup process, the coating metal foil to thereby form an upper terminal part of the first principal surface side connection terminal;
• and,
• a base removing process that removes the base after the opening forming process and the terminal forming process.

A method of manufacturing a multilayer wiring substrate having:

• a stacked configuration multilayered by alternately stacking a plurality of resin insulating layers formed with a same material as a main element and a plurality of conductor layers;
• a plurality of first principal surface side connection terminals arranged on a first principal surface of the stacked configuration;
• a plurality of a second principal surface side connection terminals arranged on a second principal surface of the stacked configuration;
• and the plurality of conductor layers arranged in the plurality of resin insulating layers, and connected by a via conductor that becomes expanded in diameter along a direction of facing the first principal surface;
• the method comprising:
• a base preparing process that prepares a base on which stacking metal foils are stacked in a peelable state;
• a buildup process that alternately stacks the plurality of conductor layers and the plurality of resin insulating layers on the stacking metal foils to form the stacked configuration;
• an opening forming process that performs, after the buildup process, a laser drilling process on a resin insulating layer of an uppermost outer layer to thereby form a plurality of openings, each opening exposing a conductor layer portion corresponding to a lower terminal part of each of the plurality of first principal surface side connection terminals;
• an entire plating process that performs electroless copper plating on the stacked configuration to form an entire plating layer that covers the plurality of openings and the plurality of resin insulating layers;
• a terminal forming process that partly etches, after the entire plating process, the entire plating layer formed on the resin insulating layer of the uppermost outer layer to form an upper terminal part of each of the plurality of first principal surface side connection terminals at a region surrounding an upper portion of each opening;
• and,
• a base removing process that removes the base after the opening forming process and the terminal forming process.