Effects of multi-cracks and thermal-mechanical coupled load on the TSV reliability

Abstract

Three-dimensional (3D) integrated packaging technology is gradually moving from the laboratory to the market. Through silicon via (TSV) is the most critical structural unit in 3D integrated packaging. However, during the TSV manufacturing process flow and its service process, many micro cracks will be generated in the TSV microstructure. The multi-cracks seriously threaten the reliability of the TSV and affect the device performance and service life. The existing literature often focus on a single crack under thermal load alone, which obviously does not match the actual situation and leads to larger analysis errors. Based on the theory of elastoplastic fracture mechanics and multi-physics coupling analysis, this paper explored the effects of multi-cracks and thermal-mechanical coupled load on the reliability of TSVs using numerical analysis. Using the J integral value as the indicator, the effects of crack numbers, crack locations, crack lengths, crack propagation directions and thermal-mechanical coupled load on the crack propagation of TSV structures were studied. Based on the research results, suggestions were made for TSV structure design and manufacturing process optimization. The main goal of this paper is to explore the influence of cracks and thermal-mechanical coupled loads on TSV microstructure through numerical analysis. Due to the micro-scale of the TSV structure, the above targets are difficult to obtain through experimental tests. The research methods and results of this paper can provide important references for the reliability evaluation and optimization design of TSV microstructures.