Trench Capacitor Structure for Semiconductor Chip Area Reduction
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Solution Overview
Problem
Existing integrated circuits with power transistors and capacitors face challenges in efficient integration of capacitors, particularly in saving area on semiconductor chips, as planar capacitors do not offer optimal integration schemes.
Innovation Solution
The integration of a trench capacitor structure within a semiconductor substrate, where a trench is etched with different portions for conductive and capacitor components, allowing for a capacitor electrode to line the sidewall of the trench portion, enabling efficient use of space and integration with transistor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar capacitors are used in integrated circuits, then the capacitor structure is simple to manufacture, but the area occupied on the semiconductor chip is large
Solution Approach 1:
The patent transitions from planar (2D) capacitor structures to three-dimensional (3D) trench-based capacitor structures. By etching trenches into the semiconductor substrate and forming capacitor electrodes within these vertical trenches, the design utilizes the third dimension (depth) to increase capacitance without proportionally increasing the horizontal chip area. This dimensional transition allows for higher integration density while maintaining manufacturability through established trench etching and filling processes.
Solution Approach 2:
The patent implements nested structures by placing capacitor electrodes within trenches that are themselves embedded in the semiconductor substrate. The trench capacitor structure is nested within the overall integrated circuit architecture, allowing multiple functional elements (transistors, capacitors, interconnects) to be vertically stacked and horizontally integrated in a compact arrangement. This nesting approach maximizes space utilization while maintaining structural integrity.
2Quantity of substance
If larger capacitor electrodes are formed to increase capacitance, then the capacitance value increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the capacitor structure into segmented components: trench formation, dielectric layer deposition, and electrode material filling. By segmenting the manufacturing process into discrete, controllable steps, each with specific precision requirements, the overall system achieves high capacitance values without requiring excessive precision in any single step. The trench depth, dielectric thickness, and electrode fill volume can be independently optimized and controlled.
Solution Approach 2:
The patent utilizes parameter changes in the trench capacitor structure, particularly varying the trench depth, dielectric layer thickness, and electrode material properties to achieve desired capacitance values. By adjusting these parameters within achievable manufacturing ranges, the design achieves high capacitance without pushing manufacturing precision to unrealistic levels. The vertical dimension (trench depth) provides an additional parameter for tuning capacitance that is easier to control than horizontal dimensions.
Data Source
AI summary
A semiconductor device in a semiconductor substrate includes a trench in a first main surface of the semiconductor substrate. The trench includes a first trench portion extending in a first direction and a second trench portion extending in the first direction. The first trench portion is connected with the second trench portion in a lateral direction. The first trench portion and the second trench portion are arranged one after the other along the first direction. The semiconductor device further includes a trench conductive structure having a conductive material disposed in the first trench portion, and a trench capacitor structure having a capacitor dielectric and a first capacitor electrode disposed in the second trench portion. The first capacitor electrode includes a layer lining a sidewall of the second trench portion.