Substrate-on-substrate structure and electronic device comprising the same

An electronic device, comprising:

• a mainboard;
• a first printed circuit board disposed on an upper side of the mainboard;
• a second printed circuit board disposed on an upper side of the first printed circuit board;
• an electronic component disposed on an upper side of the second printed circuit board;
• a reinforcing structure disposed between the first and second printed circuit boards, attached to a lower side of the second printed circuit board, and spaced apart from the first printed circuit board;
• and
• an underfill resin disposed between the first and second printed circuit boards, and covering at least a portion of the reinforcing structure,
• wherein the underfill resin is disposed between the first printed circuit board and the reinforcing structure.

A substrate-on-substrate structure, comprising:

• a mainboard;
• a first printed circuit board;
• first electrical connection metals disposed on a lower side of the first printed circuit board;
• a second printed circuit board disposed on an upper side of the first printed circuit board;
• second electrical connection metals disposed between the upper side of the first printed circuit board and a lower side of the second printed circuit board, and connecting the first printed circuit board and the second printed circuit board to each other;
• third electrical connection metals disposed on an upper side of the second printed circuit board;
• and
• a reinforcing structure disposed between the first and second printed circuit boards, attached to the lower side of the second printed circuit board, and spaced apart from the first printed circuit board,
• wherein the first printed circuit board is mounted on the mainboard through the first electrical connection metals.