Through-Silicon Vias Isolated from Bulk Micro Defects
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Solution Overview
Problem
Through-silicon vias (TSVs) in semiconductor devices are affected by bulk micro defects (BMDs) in silicon substrates, which can impair the electrical connectivity and reliability of the devices.
Innovation Solution
A defect-free layer is formed on the substrate surface through thermal treatment, preventing BMDs from affecting the TSVs, and ensuring that the TSVs are not in contact with the bulk layer containing BMDs, thereby maintaining the BMDs' functionality as gettering sites for impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TSVs are formed by creating openings in the silicon substrate, then electrical connectivity between front surface devices and rear surface terminals is achieved, but bulk micro defects in the substrate affect the reliability and electrical performance of the TSVs
Solution Approach 1:
The silicon substrate is segmented into two distinct layers: a defect-free upper layer and a bulk layer containing micro defects. The TSV openings are confined to the defect-free upper layer, physically separating the TSVs from the harmful defects in the bulk layer while maintaining electrical connectivity functionality.
Solution Approach 2:
The harmful bulk micro defects are extracted or excluded from the TSV formation region. By limiting TSV openings to the defect-free upper layer and removing or isolating the bulk layer, the harmful factors are separated from the TSV structure, preventing their negative impact on electrical reliability.
2Reliability
If the bulk layer containing BMDs is removed to protect TSVs from defects, then TSV reliability is improved, but the gettering functionality of the bulk layer for impurities is lost
Solution Approach 1:
The substrate structure is segmented into functional zones: the defect-free upper layer dedicated to TSV formation for reliable electrical connectivity, and the bulk layer retained for its impurity gettering function. This spatial segmentation allows both conflicting requirements to be satisfied simultaneously in different regions.
Solution Approach 2:
Different regions of the substrate are assigned different qualities and functions: the upper layer is maintained defect-free with high purity for TSV reliability, while the bulk layer retains its characteristic micro defects that provide impurity gettering capability. Each layer's local properties are optimized for its specific function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the reliability and performance of TSVs by isolating them from defects, ensuring stable electrical connections and maintaining the bulk layer's impurity-gettering capability, thus improving the overall semiconductor device's quality.
Implementation Method 1
a thermal treatment is performed on a substrate, thereby forming a defect free layer in an upper layer of the substrate
Data Source
AI summary
In a method of manufacturing a semiconductor device, a thermal treatment is performed on a substrate, thereby forming a defect free layer in an upper layer of the substrate, where a remaining layer of the substrate is a bulk layer. A density of defects in the bulk layer is equal to or more than 1×108 cm−3, where the defects are bulk micro defects. An electronic device is formed over the defect free layer. An opening is formed in the defect free layer such that the opening does not reach the bulk layer. The opening is filled with a conductive material, thereby forming a via. The bulk layer is removed so that a bottom part of the via is exposed. A density of defects in the defect free layer is less than 100 cm−3.