Silicon interposers embedded with ultra-deep through-silicon vias(TSVs)are in great demand for the heterogeneous integration and packaging of opto-electronic chiplets and microelectromechanical systems(MEMS)devices.Co...Silicon interposers embedded with ultra-deep through-silicon vias(TSVs)are in great demand for the heterogeneous integration and packaging of opto-electronic chiplets and microelectromechanical systems(MEMS)devices.Considering the cost-effective and reliable manufacturing of ultra-deep TSVs,the formation of continuous barrier and seed layers remains a crucial challenge to solve.Herein,we present a novel dual catalysis-based electroless plating(ELP)technique by tailoring polyimide(PI)liner surfaces to fabricate dense combined Ni barrier/seed layers in ultradeep TSVs.In additional to the conventional acid catalysis procedure,a prior catalytic step in an alkaline environment is proposed to hydrolyze the PI surface into a polyamide acid(PAA)interfacial layer,resulting in additional catalysts and the formation of a dense Ni layer that can function as both a barrier layer and a seed layer,particularly at the bottom of the deep TSV.TSVs with depths larger than 500μm and no voids are successfully fabricated in this study.The fabrication process involves low costs and temperatures.For a fabricated 530-μm-deep TSV with a diameter of 70μm,the measured depletion capacitance and leakage current are approximately 1.3 pF and 1.7 pA at 20 V,respectively,indicating good electrical properties.The proposed fabrication strategy can provide a cost-effective and feasible solution to the challenge of manufacturing ultra-deep TSVs for modern 3D heterogeneous integration and packaging applications.展开更多
基金supported in part by the National Natural Science Foundation of China under grants 92373105,62350710218,and 62074015in part by the China Postdoctoral Science Foundation under grant 2023M730237.
文摘Silicon interposers embedded with ultra-deep through-silicon vias(TSVs)are in great demand for the heterogeneous integration and packaging of opto-electronic chiplets and microelectromechanical systems(MEMS)devices.Considering the cost-effective and reliable manufacturing of ultra-deep TSVs,the formation of continuous barrier and seed layers remains a crucial challenge to solve.Herein,we present a novel dual catalysis-based electroless plating(ELP)technique by tailoring polyimide(PI)liner surfaces to fabricate dense combined Ni barrier/seed layers in ultradeep TSVs.In additional to the conventional acid catalysis procedure,a prior catalytic step in an alkaline environment is proposed to hydrolyze the PI surface into a polyamide acid(PAA)interfacial layer,resulting in additional catalysts and the formation of a dense Ni layer that can function as both a barrier layer and a seed layer,particularly at the bottom of the deep TSV.TSVs with depths larger than 500μm and no voids are successfully fabricated in this study.The fabrication process involves low costs and temperatures.For a fabricated 530-μm-deep TSV with a diameter of 70μm,the measured depletion capacitance and leakage current are approximately 1.3 pF and 1.7 pA at 20 V,respectively,indicating good electrical properties.The proposed fabrication strategy can provide a cost-effective and feasible solution to the challenge of manufacturing ultra-deep TSVs for modern 3D heterogeneous integration and packaging applications.
