| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of via processing of a ceramic green sheet with a laser beam which enables forming through a vias of a diameter of 30-50μm in a ceramic green sheet of a thickness of≤250μm with a taper rate equal to or higher than 60% and lower than 100% with good precision without influence of heat. SOLUTION: A ceramic powder for the ceramic green sheet 1 is prepared with such grain sizes as to give a taper rate of≥60% by using the equation 3 for the 90% grain size (D90) in the number accumulated grain size distribution of the ceramic powder: Ta/100≥-0.024d<SP>3</SP>+0.302d<SP>2</SP>-1.233d+2.191; Ta=ϕ<SB>via'</SB>/ϕ<SB>via</SB>×100%;ϕ<SB>via</SB>≥ϕ<SB>via'</SB>; and 60%≤Ta<100%, and the ceramic green sheet is irradiated continuously with a laser pulse 4 shown in Fig.3a at positions of the same coordinates so as to form vias. COPYRIGHT: (C)2010,JPO&INPIT
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