TSV Structure Stabilization via Dielectric Cap and Dual-Material Fill
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Solution Overview
Problem
The evolution of semiconductor devices to dual-damascene structures renders through-silicon-via (TSV) structures susceptible to 'popping up' due to the elimination of metal pads, and reintroducing metal pads increases complexity and cost, potentially decreasing product yield.
Innovation Solution
A method for forming a TSV structure where a first portion is filled with a first conductive material, and a second portion is filled with a second conductive material substantially simultaneously with the formation of interconnect features, using conductive materials like copper or aluminum, and forming barrier layers to stabilize the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dual-damascene structures are used to evolve semiconductor devices, then manufacturing precision is improved, but TSV structure stability deteriorates due to elimination of metal pad
Solution Approach 1:
A dielectric cap layer is introduced as an intermediary element between the TSV structure and the dual-damascene interconnect features. This cap layer serves as a protective mediator that stabilizes the TSV structure during manufacturing processes, preventing popping up while allowing the dual-damascene precision features to be formed. The cap layer is subsequently removed to reveal the stabilized TSV structure.
Solution Approach 2:
The TSV structure is formed and stabilized with a dielectric cap layer before the dual-damascene interconnect features are formed. This preliminary stabilization action ensures that the TSV structure is protected from subsequent manufacturing processes that would otherwise cause it to pop up, allowing the high-precision dual-damascene features to be formed without compromising TSV stability.
2Stability of the object's composition
If metal pad is reintroduced to cover TSV structure, then TSV structure stability is improved, but device complexity increases
Solution Approach 1:
Instead of reintroducing a metal pad, a dielectric cap layer is used as a temporary intermediary to stabilize the TSV structure. This approach provides the necessary stability during manufacturing without the complexity of adding another metal layer and associated patterning processes. The dielectric cap is simpler to apply and remove than a metal pad structure.
Solution Approach 2:
The dielectric cap layer is a temporary, disposable structure used only during the critical manufacturing window when TSV stability is needed. It is formed, provides stabilization, and then removed to reveal the final structure. This temporary measure avoids the permanent complexity of adding a metal pad while achieving the necessary stability during processing.
3Stability of the object's composition
If additional manufacturing steps are added to stabilize TSV structure, then TSV structure stability is improved, but productivity decreases
Solution Approach 1:
The formation of the dielectric cap layer is merged with the existing interconnect formation processes. The cap layer is formed as part of the dielectric layer deposition sequence that is already required for the dual-damascene structures. This merging approach adds minimal steps while providing comprehensive TSV stabilization throughout the manufacturing process.
Solution Approach 2:
The dielectric cap layer provides continuous stabilization of the TSV structure throughout the entire manufacturing process, from TSV formation through interconnect fabrication. This continuous protection eliminates the need for multiple discrete stabilization steps, maintaining productivity while ensuring TSV stability is preserved throughout all subsequent processing.
Data Source
AI summary
Methods and apparatus entailing an interconnect structure comprising interconnect features disposed in dielectric material over a substrate. Each interconnect feature comprises an interconnect member and a via extending between the interconnect member and a conductive member formed within the dielectric material. A through-silicon-via (TSV) structure is formed laterally offset from the interconnect structure by forming a first portion of the TSV structure with a first conductive material and forming a second portion of the TSV structure with a second conductive material. Forming the second portion of the TSV structure occurs substantially simultaneously with forming one of the interconnect features.