| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a metal core to be used for double sided metal clad laminate for a metal-cored semiconductor plastic package printed wiring board, which is good in adhesion with surface layer metal foil, excellent in heat dissipation and the heat resisting property after absorbing moisture. SOLUTION: Solder is printed on the position where a conical trapezoidal protrusion on the surface of a metal flat plate, an etching resist is arranged on the area other than the clearance hole forming part on the backside of the metal flat plate, and by forming an inner layer metal core by spraying an alkaline etchant at low pressure on the surface, and by spraying the alkaline etchant at higher pressure on the backside, a printed wiring board double sided metal clad laminate having excellent close contactness with the metal foil on the surface after formation of lamination, having the upper and the lower clearance holes almost in the same diameter, and having excellent insulating property of through hole and metal plate, can be obtained. As a result, the metal core to be used for the laminate can be obtained.</p> |
