③. 过孔(VIA) 一般为1.27mm/0.7mm(50mil/28mil); 当布线密度较高时,过孔尺寸可适当减小,但不宜过小,可考虑采用1.0mm/0.6mm(40mil/24mil)。 ④. 焊盘、线、过孔的间距要求 : PAD and VIA : ≥ 0.3mm(12mil) : PAD and PAD : ≥ 0.3mm(12mil) : PAD and TRACK : ≥ 0.3mm(12mil) ) : TRACK and TRACK : ≥ 0.3mm(12mil) : 密度较高时: : PAD and VIA : ≥ 0.254mm(10mil) : PAD and PAD : ≥ 0.254mm(10mil) : PAD and TRACK : ≥ 0.254mm(10mil) : TRACK and TRACK : ≥ 0.254mm(10mil)