Multi-Electrode Trench Capacitor Layout for Higher Capacitance Density
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Solution Overview
Problem
Conventional Metal-Insulator-Metal (MIM) capacitors face challenges in increasing capacitance density due to difficulties in etching trenches with larger aspect ratios, leading to potential electrode connection issues from oblique angles, which limits the number of capacitors that can be packed in a unit area, especially in 5G antenna tuners.
Innovation Solution
A parallel-connected capacitor structure is fabricated using a substrate with trenches having perpendicular sidewalls, where multiple electrode layers are formed through electroplating processes, with a capacitor dielectric layer between each pair of electrodes and conductive plugs contacting specific electrode layers, allowing for easier dry etching and higher capacitance density without electrode connection issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the aspect ratio of the trench is increased to increase capacitance density, then the capacitance density is improved, but the difficulty of etching increases and oblique angles occur at the trench edge
Solution Approach 1:
The single large capacitor is segmented into multiple smaller capacitors arranged in parallel within the same trench. The trench is divided into multiple regions with individual electrode pairs, allowing each segment to be etched with standard aspect ratios while achieving high total capacitance through parallel connection of multiple units.
Solution Approach 2:
The design transitions from increasing capacitance by deepening a single trench (vertical dimension) to increasing capacitance by adding multiple electrode layers and parallel capacitor units within the same trench depth (lateral and layered dimensions). This allows high capacitance density without increasing the trench aspect ratio.
2Quantity of substance
If the aspect ratio of the trench is increased to increase the number of capacitors in unit area, then the capacitance density is improved, but electrode connection issues occur due to oblique angles
Solution Approach 1:
Multiple separate capacitor units are created within the trench, each with its own electrode pairs and dielectric regions. This segmentation allows independent formation and connection of each capacitor unit, avoiding the need for continuous filling of deep trenches that creates oblique angle problems.
Solution Approach 2:
The solution moves from vertical stacking in deep trenches to lateral arrangement of multiple capacitor units and multi-layer electrode structures. Capacitors are distributed across multiple layers and positions within the trench, achieving high density without requiring excessive trench depth.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the creation of a higher number of capacitors in a smaller area with improved capacitance density, facilitating easier dry etching and reducing the risk of electrode connections, thus addressing the limitations of conventional technologies.
Implementation Method 1
a plurality of electroplating processes is performed to form a plurality of electrode layers filling in the trenches
Data Source
AI summary
A structure of capacitors connected in parallel includes a substrate. A trench embedded in the substrate. Numerous electrode layers respectively conformally fill in and cover the trench. The electrode layers are formed of numerous nth electrode layers, wherein n is a positive integer from 1 to M, and M is not less than 3. The nth electrode layer with smaller n is closer to the sidewall of the trench. When n equals to M, the Mth electrode layer fills in the center of the trench, and the top surface of the Mth electrode is aligned with the top surface of the substrate. A capacitor dielectric layer is disposed between the adjacent electrode layers. A first conductive plug contacts the nth electrode layer with odd-numbered n. A second conductive plug contacts the nth electrode layer with even-numbered n.