| 摘要 |
PURPOSE:To prevent a temperature rise by the friction heat, breakage of a drill bit or the like by arranging a polymer sheet whose main composition is the special water soluble polymer compound on the laminated substrate surface to realize drilling. CONSTITUTION:Dimethyl terephthalate of about 2. 2 pts.wt. is blended in polyethylene glycol of 10 pts.wt. (weight-average molecular weight :10000) to be obtained by adding ethylene oxide to ethylene glycol. Then, the water soluble polymer compound to be expressed by the formula I of a weight-average molecular weight of about 130,000 and the viscosity of the aqueous solution of about 250 cps (at 30 deg.C, by Type B viscometer) and expressed by the repeated unit is obtained. Where, A, X and R2 are expressed by the formula II. A polymer sheet whose main composition is this water soluble polymer compound is arranged on the surface of the laminated substrates where the metallic foil is adhered and laminated on the insulating body. In this condition, a through hole is made in the laminated substrates through this sheet. |
