Through-Silicon Via Insulation Layout to Block Material Diffusion
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Solution Overview
Problem
In semiconductor devices with through-silicon vias (TSVs), the electrical insulation of the side surface of the TSV from the substrate is challenging, leading to potential failure and reduction in reliability of electrical characteristics due to diffusion of TSV materials into active or passive devices.
Innovation Solution
The semiconductor device includes a substrate with a via insulating layer and a through-silicon via, where the center of the through-silicon via is misaligned from the center of the via insulating layer. A blocking layer and a contact plug are used to ensure electrical insulation and prevent material diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through-silicon via is formed extending through the substrate, then electrical connectivity through the substrate is improved, but material diffusion from the via into active or passive devices occurs causing electrical characteristic failure
Solution Approach 1:
An insulating layer is introduced as an intermediary substance between the through-silicon via and the substrate. This mediator prevents direct contact between the via material and substrate, thereby blocking material diffusion while maintaining electrical connectivity through the via structure.
Solution Approach 2:
The via structure is segmented into distinct sections: a conductive through-silicon via portion and an insulating layer portion. This segmentation allows the via to provide electrical connectivity in conductive regions while providing electrical insulation in regions where material diffusion prevention is needed.
2Reliability
If the side surface of the through-silicon via is electrically insulated from the substrate, then material diffusion is prevented, but manufacturing complexity increases due to additional insulating structures
Solution Approach 1:
The insulating layer serves multiple functions simultaneously: it provides electrical insulation between the via and substrate, prevents material diffusion into active devices, and acts as a barrier layer during subsequent processing steps. This multi-functionality reduces the need for additional separate structures.
Solution Approach 2:
The insulating layer is merged with the via formation process itself, being deposited conformally on the via walls during the same processing sequence. This integration combines the insulation function with the via fabrication, reducing overall process complexity compared to adding a separate insulation step.
3Ease of manufacture
If conventional alignment is used for via insulating layer and through-silicon via, then manufacturing process is simple, but misalignment causes material diffusion into active devices
Solution Approach 1:
The via insulating layer is formed preliminarily before the through-silicon via is completely defined. By establishing the insulating barrier in advance, the patent ensures that even if subsequent via formation steps experience alignment variations, the pre-formed insulating layer will prevent material diffusion into active devices.
Solution Approach 2:
The via insulating layer acts as a cushioning barrier formed beforehand to compensate for potential alignment errors in subsequent via formation steps. This protective layer provides a margin of error, cushioning against misalignment that would otherwise cause material diffusion and device failure.
Data Source
AI summary
A semiconductor device includes a substrate including a first surface, and a second surface opposing the first surface. A via insulating layer extending through the substrate is disposed. A through-silicon via extending through the via insulating layer is disposed. The center of the through-silicon via is misaligned from the center of the via insulating layer. A blocking layer is disposed on the first surface. A first insulating layer is disposed on the blocking layer. A contact plug contacting the through-silicon via and extending through the first insulating layer and the blocking layer is disposed.