Buried Interconnect Layout Through Trench Isolation for Lower Latency

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Solution Overview

Problem

Existing semiconductor technologies face challenges in achieving high routing density and reducing latency in dense logic and memory blocks due to limitations in wire routing and trench isolation structures.

Innovation Solution

The implementation of buried interconnect structures made of metal materials within the semiconductor substrate, which cross trench isolation structures, along with via interconnects that contact the buried interconnects and extend through the trench isolation structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional wire routing is used in semiconductor substrate, then trench isolation structures can be formed, but routing density is limited and latency increases

Engineering Contradiction:
Improverouting densityVSAvoidlatency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent introduces buried interconnect structures that extend vertically through the substrate thickness, utilizing the third dimension (depth) for routing. This allows interconnects to pass through the substrate at different depths, effectively adding a vertical routing dimension that increases overall routing density without consuming additional lateral area on any single layer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The interconnect system is segmented into multiple levels: conventional wire routing layers on the substrate surface and buried interconnect structures at different depths within the substrate. This segmentation allows simultaneous use of both surface and subspace routing resources, increasing total routing capacity while maintaining organized signal paths at different levels.

Inventive Principle:
Principle #1Segmentation

2Productivity

If more wire routing layers are added to increase routing density, then routing capacity improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improverouting densityVSAvoidrouting structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the substrate itself with the interconnect structure by forming conductive paths within the substrate material. Instead of adding separate routing layers on top of the substrate, the substrate is transformed into an active routing medium, combining the substrate function with the interconnect function and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substrate serves multiple functions: it provides mechanical support, electrical isolation through trench structures, and conductive pathways through the buried interconnects. This multi-functionality reduces the need for additional dedicated routing layers, simplifying the overall device structure while maintaining high routing density.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional routing schemes are used, then manufacturing processes are simpler, but routing density is insufficient for dense logic and memory blocks

Engineering Contradiction:
Improverouting densityVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The buried interconnect structures are formed within the substrate before final device assembly and wiring. This preliminary formation of conductive paths at substrate level allows subsequent routing layers to connect to pre-established deep interconnect points, simplifying the overall manufacturing sequence by establishing the routing backbone early in the process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4546404A1Buried interconnect traversing trench isolation
Publication Date: 2025.04.30 GLOBALFOUNDRIES US INC
  • EP4546404A1 patent drawingFigure 1A~1B
  • EP4546404A1 patent drawingFigure 2~3
  • EP4546404A1 patent drawingFigure 4A~4B

AI summary

The present disclosure relates to semiconductor structures and, more particularly, to buried interconnect structures and methods of manufacture. The structure includes: a semiconductor substrate; a trench isolation structure extending into the semiconductor substrate; and at least one buried interconnect structure in the semiconductor substrate and crossing the trench isolation structure.