Method of making plated through hole printed circuit board

In a circuit board having first and second surfaces and comprising a substrate, a first circuit element on one side of the substrate, and a second circuit element on the opposite side of the substrate,

• a method of making a connection from one circuit element to the other through the substrate, said method comprising:
• a. providing in the circuit board a through hole extending through both circuit elements and through the substrate,
• b. applying a sensitizing coating to exposed surface areas of the board,
• c. applying a resist material to the first and second planar surfaces of the board,
• d. pressing portions of the first and second circuit elements adjacent said hole from the planes of, respectively, the first and second board surfaces into the hole to make first and second inwardly flared circuit element portions, and removing resist material from said inwardly flared circuit portions, and
• e. electrolessly plating exposed areas of the board to form a through hole connection having a middle portion extending through the hole and two end portions overlapping and connecting to the inwardly flared circuit element portions.

In a circuit board having first and second surfaces and comprising a substrate, a first circuit element on one side of the substrate, and a second circuit element on the opposite side of the substrate,

• a method of making a connection from one circuit element to the second circuit element through the substrate, said method comprising:
• a. providing in the circuit board a through hole extending through both circuit elements and through the substrate,
• b. pressing portions of the first and second circuit elements adjacent said hole from the planes of, respectively, the first and second surfaces, into the hole to make first and second inwardly flared circuit element portions,
• c. applying a sensitizing coating to exposed surface areas of the board,
• d. electrolessly plating the exposed surface areas of the board,
• e. applying a plating resist material to the first and second planar surfaces of the board to leave the hole area and the inwardly flared circuit element portions exposed, and
• f. electrolytically plating the exposed surface area to form a through hole connection having a middle portion extending through the hole and two end portions overlapping and connecting electrically to the inwardly flared circuit element portions.