Electrochemical Deposition Behavior In Large Aspect Ratio Micron Pore

In recent years,silicon through-hole?TSV?technology has been widely used in electronic packaging,but the uniform filling of metal in the through-hole with large aspect ratio is a difficult problem to be solved.The study on the electrochemical deposition of metals in the channels with large aspect ratio is helpful to deepen the understanding of the problem and is of great significance to solve the problem of uniform filling of metals in micron channels.In this paper,a large-diameter?>50?silicon microporous array?porous silicon?template was prepared by photoelectrochemical etching technique,and copper was deposited in the channel by constant-voltage pulse method using a three-electrode system with 0.22 mol/L CuSO₄ solution as electrolyte.The effects of etching voltage,etching solution ratio and etching time on the size and morphology of porous silicon were studied.the effects of deposition voltage,conductive substrate thickness and silicon empty array structure on the electrochemical deposition of copper in micropores were also studied.The main findings and findings are as follows:?1?Using HF buffer solution and KOH solution as etching solution,the prefabrication pit of porous silicon can be prepared by mask technology,and the better process parameters can be determined;The solution ratio of HF buffer solution is:HF solution?49 wt%,14 mL?,NH₄F?30 g?and H₂O?50 mL?mixed solution.The concentration of KOH solution is 30wt%,the corrosion temperature is 80?and the corrosion time is 40 min.?2?Using LED lamp and Halogen Lamp as light source,porous silicon array templates with large aspect ratio were prepared.The effects of etching voltage,etching solution ratio and etching time on the morphology of porous silicon arrays were investigated.When LED lamp is used as light source,the porous silicon channels with smooth wall and neat array can be prepared under the etching voltage of 0.3 V and HF:C₂H₅OH:H₂O=20:140:20?volume ratio?.The length-diameter ratio is about 20.When Halogen lamp is used as light source,porous silicon arrays with uniform diameter,neat structure and larger aspect ratio can be prepared under the etching voltage of 1.3 V and HF:C₂H₅OH:H₂O=20:140:20?volume ratio?.The aspect ratio reaches about 52.?3?The effects of deposition voltage,conductive substrate thickness and channel diameter on the electrochemical deposition behavior of copper in micrometer channels were investigated by using electrochemical deposition technique,the morphologies of different microstructures were analyzed.The results show that with the increase of the deposition voltage,the morphology of copper deposits in the channels presents dendritic,rod and porous structure.With the increase of the substrate thickness,the morphology of copper deposits presents dendritic and rod structure.With the increase of pore diameter,the morphology of copper deposits presents dendritic structure and rod structure.Porous silicon templates with large aspect ratio?>50?were successfully prepared by photoelectrochemical etching technique,and the effect of deposition conditions in the channels on the microstructure morphology of copper was investigated,at the same time,the deposition behavior of copper in micron channels with large aspect ratio is analyzed,which provides some basis for TSV?silicon through-hole?technology and micron-scale controllable coded metal array research.