Research Of Electroplating Process In Through Silicon Via

In order to reduce the feature size, interconnect delay and other issues, three-dimensional integration technology has become a hot topic in the field of packaging. TSVis the mainstream3D integration technology, also known as the fourth-generationpackaging technology. In the process technology of TSV, the filling quality of the siliconhole directly affects the performance of the3D integration chip. This article is focused onthe TSV electroplating technology, elaborating the plating process, growth mechanism andexploring the impact to the conformal plating in blind holes by changing the processparameters and condition of plating solution. Meanwhile, a new bottom-up filling methodis proposed, to achieve a void-free filling in the blind holes. The main contents are asfollows:(1) Conformal plating technology in the blind holes was analyzed and the differencesof the plating quality by the varying the wetting method and changing the condition of theplating solution were compared, in order to improve the conformal plating by optimizingthe plating process parameters. The mechanism that leads to the defects was also grasped.(2) The filling effects in the blind holes at different times were researched to knowthe specific conformal plating growth mechanism. The different filling effects in the blindholes by applying different current densities were also studied. By increasing the currentdensity, the rate of metal deposition can be increased to reduce the plating time. However,the over-burden will be thickened and the filling defeats will be occurred frequently.(3)Using the barrier layer as the conductive medium for plating was proposed and thespin-coating process was improved to completely fill the blind holes with photoresist. Onthese bases, we proposed a new bottom-up filling method to achieve a void-free filling inthe blind holes.In this paper, plating process parameters in the blind holes were researched and a newbottom-up filling method was proposed, guiding for a better filling in the blind holes. Themechanism of plating defects was mastered, paving the way for the defect detection.