一种高密度薄膜多层布线基板BCB通孔制作技术

Research on BCB via dielectric technology for high density multilayer substrate

为提高高密度薄膜多层布线基板的BCB通孔质量,提出一种高密度、微小通孔的间歇旋转喷淋显影新方法,利用激光扫描共聚焦显微镜和扫描电镜,对间歇旋转喷淋显影和传统浸没显影的BCB通孔显微形貌和微观结构进行了对比分析,同时,用扫描电镜和四探针测试仪,对间歇旋转喷淋显影的BCB通孔导通电阻及通孔互连剖面进行了研究.结果表明:间歇旋转喷淋显影与传统浸没显影相比,50和20μm通孔内部显影充分,通孔轮廓边缘光滑;通孔内部基本没有杂质富集,无BCB胶底膜残存.不同位置区域对通孔导通电阻影响较小,50和20μm通孔导通电阻平均偏差均小于1 mΩ;而不同的显影时间和喷淋压力对通孔导通电阻影响较大,当显影时间为65～90 s,或当喷淋压力为5～20 MPa时,50μm通孔导通电阻均下降至10 mΩ,20μm通孔导通电阻均下降至40 mΩ; 50和20μm通孔台阶覆盖良好.采用此显影方法制作出高密度薄膜多层布线基板实物,互连导通率均达到100%.

In order to improve the quality of the BCB vias of high density thin film muhilayer substrate, a new method of intermittent rotary spray development with high density and micro via is proposed. The micro- morphology and the microstructure of BCB vias in intermittent rotating spray development and traditional immersion development were compared and analyzed by laser scanning confocal microscopy and scanning election microscopy. Meanwhile,the via on-resistance and via interconnection profiles of BCB in intermittent rotating spray development were studied with the scanning election microscopy and the four-point probe taser. The ~sults showed that compared with the traditional immersion development, the intermittent rotating spray development is fully developed within 50 micron and 20 micron vias, and the outline of the vias is smooth. There were no impurities and no BCB residual plastic film in the inside of the vias. Different locations had little influence on the via on-resistance. The average deviation of 50 micron and 20 micron via on-resistance was less than 1 mΩ Different development time and spray pressre had gloat influence on the via on- resistance. When the development time was 65 -90 s, or when the spray pressre was 5 -20 MPa, the 50 micron via on-resistance was reduced to 10 mΩ, while the 20 micron via on-resistance was reduced to 40 mΩ The step coverages of 50 micron and 20 micron vias were well. By using the developing method, the high density muhilayer substrate was successfully fabricated to 100% , and the interconnection conduction rate was all up