Fine‐pitch through‐silicon via integration with self‐aligned back‐side benzocyclobutene passivation layer

Abstract

A fine-pitch through-silicon via integration approach with self-aligned back-side benzocyclobutene passivation layer is proposed. Different from the conventional lithographic process, the passivation layer is realised by leveraging plasma etching and chemical-mechanical polishing process. With its well-controlled repeatability, this approach can help reduce the process defect and copper contamination. A plenty of measurement techniques including X-ray radiographic testing, optical and scanning electron microscope observation, four-probe electrical measurement, as well as vector network analyser, are employed in order to verify the fabrication quality and the electrical performances. All the test results support that this fine-pitch through-silicon via integration approach has a promising application prospect.