Backside Via Interconnect for Semiconductor Wafer Signal Isolation
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Solution Overview
Problem
Current semiconductor technologies face challenges in creating precise, repeatable, and cost-effective electrical connections through electronic chips, especially for deep vias with narrow widths and close spacing, which are prone to signal cross-talk and capacitance issues, and require expensive high-performance processes.
Innovation Solution
A process involving a semiconductor wafer with a substrate, multiple metalization layers, and electrically conductive vias that extend from the surface through the substrate to form an electrically conductive path, allowing for deep and narrow vias with controlled capacitance and resistance, suitable for active chip regions and high-frequency signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If deep vias with narrow widths and close spacing are created, then connection density and stacking efficiency are improved, but signal cross-talk and capacitance issues worsen
Solution Approach 1:
The patent introduces an electrically conductive filler material as an intermediary substance within the via structure. This filler material serves as a mediator that provides electrical connection while allowing for isolation techniques (such as dielectric coatings or spacing structures) to be applied to the via walls, thereby reducing signal cross-talk between closely spaced vias while maintaining the high connection density enabled by deep, narrow via structures.
2Ease of manufacture
If conventional processes are used for creating vias, then manufacturing simplicity is maintained, but manufacturing precision and repeatability worsen
Solution Approach 1:
The patent applies preliminary action by pre-coating the via walls with electrically insulating material before filling with conductive material. This preliminary insulating layer is deposited on the via walls prior to the filling process, ensuring that the conductive filler material does not create unintended electrical connections with adjacent structures. This preliminary protective action enables achieving high manufacturing precision and repeatability for deep, narrow vias while maintaining relatively simple manufacturing processes.
3Manufacturing precision
If high-performance processes are used, then via precision and electrical performance are improved, but manufacturing cost increases
Solution Approach 1:
The patent employs parameter changes by utilizing standard semiconductor fabrication processes with modified parameters - specifically, using conventional etching, deposition, and filling processes but optimizing them for the specific via dimensions and materials. The use of electrically insulating coatings followed by conductive filler material allows achieving high via precision and electrical performance through parameter optimization rather than requiring entirely new high-performance processes, thereby controlling manufacturing costs.
4Reliability
If vias are made electrically conductive, then electrical connection is improved, but capacitance and resistance problems worsen
Solution Approach 1:
The patent applies local quality by creating different electrical properties at different locations within the via structure. The via walls are coated with electrically insulating material to provide electrical isolation and reduce parasitic capacitance, while the center is filled with electrically conductive material to provide the desired electrical connection. This spatial differentiation of electrical properties allows achieving reliable electrical connection while minimizing capacitance and resistance problems through localized material selection.
Data Source
AI summary
An apparatus involves a semiconductor wafer that has been back-end processed, the semiconductor wafer including a substrate, electronic devices and multiple metalization layers, a via extending from an outer surface of the substrate through the substrate to a metalization layer from among the multiple metalization layers, and an electrically conductive material within the via, the electrically conductive material forming an electrically conductive path from the metalization layer to the outer surface. A method of processing a semiconductor wafer that has been front-end and back-end processed involves forming a via in the semiconductor wafer extending from a surface of the wafer, into and through semiconductor material, to a metalization layer formed during the back-end processing by etching the semiconductor wafer; and making the via electrically conductive so as to form an electrical path within the via extending from the surface of the wafer to the metalization layer.