TSV Protection via Insulative Annulus During Backside Grinding
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Solution Overview
Problem
Current through silicon via (TSV) technologies face challenges in protecting the via structure during backside grinding, which can lead to damage and inefficiencies in forming reliable vertical interconnections in 3D semiconductor stacks.
Innovation Solution
A semiconductor structure with an insulative annulus extending from the front side to the back side, featuring a recessed metal-filled via that includes semiconductor material between the TSV and the annulus, which is protected during wafer thinning and backside grinding, ensuring the integrity of the TSV connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TSV formation is used without protection structures, then the manufacturing process is simpler, but the TSV is damaged during backside grinding
Solution Approach 1:
The insulative annulus is formed before backside grinding to provide pre-established protection for the TSV. This preliminary protective structure prevents damage during the subsequent grinding process, resolving the contradiction by preparing the protection in advance rather than adding complexity during the critical grinding operation.
Solution Approach 2:
The insulative annulus acts as an intermediary protective layer between the TSV and the mechanical grinding process. This mediator absorbs the mechanical stress and prevents direct contact between the grinding tool and the fragile TSV, thereby protecting the via while maintaining a relatively simple overall structure.
2Productivity
If the TSV is exposed during backside grinding, then the manufacturing process is faster, but the TSV suffers damage and reliability decreases
Solution Approach 1:
The protective insulative annulus is formed in advance before the backside grinding process begins. This allows the wafer thinning and grinding operations to proceed at full speed without interruption or special handling, while the pre-positioned annulus provides continuous protection to the TSV throughout the process, thus maintaining both high productivity and reliability.
3Ease of manufacture
If no protection structure is added, then the manufacturing cost is lower, but the TSV is damaged leading to rework and higher costs
Solution Approach 1:
The insulative annulus serves as a cost-effective intermediary protection layer that can be integrated into the existing manufacturing process flow. By adding this relatively simple protective structure, the patent prevents costly TSV damage and rework, thereby improving the overall ease of manufacture despite the minor additional process steps.
4Reliability
If the TSV is recessed and protected, then the TSV is shielded during grinding, but the manufacturing process becomes more complex
Solution Approach 1:
The TSV recess and insulative annulus formation are performed as preliminary steps before the backside grinding process. By completing the protection structure setup in advance, the subsequent grinding operation can proceed without additional complexity or special handling, thus achieving TSV protection while minimizing the increase in overall process complexity.
Data Source
AI summary
A semiconductor structure having a through semiconductor via (TSV) which includes a semiconductor wafer of a semiconductor material and having a front side and a back side; front end of the line (FEOL) components; an insulative annulus extending from the front side to the back side, the insulative annulus having a center including the semiconductor material such that the semiconductor material in the center of the insulative annulus is recessed from the back side to form a recess; a metal filling the recess; a through silicon via (TSV) extending in a straight line from the metal-filled recess, through the center of the semiconductor material in the center of the insulative annulus and into the FEOL components such that there is semiconductor material between the TSV and the insulative annulus.