| 摘要 |
PROBLEM TO BE SOLVED: To provide a method by which the melt viscosity of a prepreg resin applied in a thin film-like state or the resin of metal foil coated with the resin can be measured continuously with respect to the heating temperature without scratching off the resin, the viscosity characteristic of a cured resin can be measured by using a viscosity measuring instrument which is constituted to easily remove the cured resin, and then, the molding condition can be optimized, based on the characteristic value in forming the insulating layer of a printed wiring board. SOLUTION: Between two fixed flat plates which are positioned in parallel with each other with a heatable very small clearance in between, two pieces of metal foil are inserted in such a way that the surfaces of the foil are superposed upon another when the foil is coated with the resin, and one front ends of the pieces are fixed to a pneumatic driving table. Then a fixed load is applied to the foil and the resin is melted by heating the flat plates. Then, after the viscosity characteristic of the resin is measured by detecting the moving speed fluctuation of the driving table when the resin is melted, the applying timing of a pressuring force and pressure in forming the insulating layer of the printed wiring board is decided, based on the measured value of the viscosity characteristic. |
