Deep Trench Capacitor Contact Layout for High Capacitance Density
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Solution Overview
Problem
Deep trench capacitors in semiconductor chips occupy significant device area without providing substantial capacitance due to stepped surfaces around metallic electrode layers, which limits their effectiveness in power supply stabilization and noise filtering applications.
Innovation Solution
The implementation of laterally-insulated contact structures with tubular insulating spacers and contact via structures that provide electrical isolation and contact to metallic electrode layers within the area between deep trenches, eliminating the need for stepped surfaces and optimizing the use of space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If stepped surfaces are used around metallic electrode layers, then device area is increased, but capacitance per unit area is reduced
Solution Approach 1:
The patent transitions from a planar capacitor structure to a three-dimensional deep trench structure. Metallic electrode layers are stacked vertically within the trench, separated by dielectric layers, creating multiple capacitor elements in the vertical dimension. This allows high total capacitance to be achieved within a small footprint area, effectively resolving the contradiction between device area and capacitance per unit area.
Solution Approach 2:
The patent implements a nested structure where multiple metallic electrode layers and dielectric layers are stacked within each other inside the deep trench. Each metallic electrode layer is surrounded by dielectric layers, forming a compact nested arrangement that maximizes capacitance density within the available vertical space.
2Area of stationary object
If laterally-insulated contact structures are used, then device area is minimized, but manufacturing complexity is increased
Solution Approach 1:
The contact structure is segmented into distinct functional components: tubular insulating spacers that provide lateral insulation, contact via structures that establish electrical connections, and metallic electrode layers that form the capacitor terminals. This segmentation allows each component to be optimized independently while maintaining overall compactness.
Solution Approach 2:
Tubular insulating spacers serve as intermediary elements between the contact via structures and the metallic electrode layers. These spacers provide lateral electrical insulation while allowing vertical contact, enabling compact contact arrangements without requiring stepped surfaces.
Data Source
AI summary
A deep trench capacitor includes at least one deep trench and a layer stack including at least three metallic electrode layers interlaced with at least two node dielectric layers and continuously extending over the top surface of a substrate and into each of the at least one deep trench. A contact-level dielectric layer overlies the substrate and the layer stack. Contact assemblies extend through the contact-level dielectric layer. A subset of the contact assemblies vertically extend through a respective metallic electrode layer. For example, a first contact assembly includes a first tubular insulating spacer that laterally surrounds a first contact via structure and contacts a cylindrical sidewall of a topmost metallic electrode layer.