| 摘要 |
PURPOSE:To form a substrate for a microwave circuit constituting a non-reversible circuit element by adhering an alumina substrate with lithium ferrite while heating them in vacuum to remove bubbles and pinholes. CONSTITUTION:Lithium ferrite 4 is embedded in the hole 2 of the alumina substrate 1, glass paste 3 is sucked from one side of the substrate 1 and dried and the glass paste 3 is applied to the other side and dried. Subsequently, the alumina substrate 1 and the lithium ferrite 4 are adhered with each other and printed. Namely, the alumina substrate 1 and the lithium ferrite 4 are heated from room temperature to about 750 deg.C at the rate of 400 deg.C/hr and held for 10min while being kept at <=10<-2>mm.Hg vacuum until the end of the holding time. The bubble removing effect is not sufficient under the condition >=10<-2>mm.Hg. Thus, <=10<-2>mm.Hg vacuum makes it possible to discharge air or remaining organic gas adsorbed in glass powder easily and remove bubbles. |
