Vertical Interdigitated Capacitor for High Density ICs
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Solution Overview
Problem
Traditional semiconductor capacitors with metal-on-metal (MOM) structures face challenges such as excessive area consumption, low capacitance density, and high fabrication costs as device sizes decrease, necessitating improved designs for increased functional density and reduced geometry sizes in integrated circuits.
Innovation Solution
The development of an interdigitated capacitor structure within the interconnect structure of a semiconductor device, where conductive stacks of opposite polarities are aligned in both the X and Y directions, forming a two-dimensional array with increased sidewall coupling area, utilizing dielectric material for enhanced capacitance without increasing chip space, and potentially including additional shielding for noise immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional metal-on-metal (MOM) capacitor structure is used, then fabrication process is simple, but capacitance density is low and chip area consumption is excessive
Solution Approach 1:
The patent transitions from traditional planar MOM capacitor structure to a vertical interdigitated structure that utilizes the third dimension (depth/vertical direction). Conductive stacks are arranged vertically with alternating polarities, creating multiple coupling interfaces between anode and cathode stacks. This dimensional change dramatically increases the effective capacitance area without proportionally increasing chip area, thereby improving capacitance density while maintaining fabrication feasibility through standard vertical processing techniques.
Solution Approach 2:
The patent implements nested conductive stacks where anode stacks and cathode stacks are interleaved in a alternating pattern (anode-cathode-anode-cathode). Each stack is surrounded by dielectric material, creating a nested configuration where conductive elements are embedded within dielectric layers. This nesting arrangement maximizes the coupling surface area between opposite polarity electrodes within a compact volume, significantly enhancing capacitance density.
2Productivity
If device geometry size is decreased to increase functional density, then more devices can be integrated, but traditional MOM capacitor structure encounters excessive area consumption and low capacitance density
Solution Approach 1:
By transitioning to vertical interdigitated stacks, the patent enables capacitors to achieve high capacitance values in the vertical direction rather than requiring large horizontal footprint. This allows multiple capacitors to be packed more densely on the chip surface, increasing functional density without each capacitor consuming excessive chip area.
Solution Approach 2:
The patent changes the geometric parameters of the capacitor structure from planar to vertical, and from single-layer to multi-layer interdigitated stacks. This parameter transformation increases the effective capacitance area per unit chip area, allowing higher functional density to be achieved with reduced individual capacitor footprint.
3Ease of manufacture
If traditional MOM capacitor structure is used, then fabrication cost is high, but capacitance density remains low
Solution Approach 1:
The vertical interdigitated capacitor structure can be integrated into existing semiconductor fabrication processes using standard deposition and etching techniques. The same processing equipment and material layers used for interconnect structures can be utilized to form the capacitor stacks, enabling multi-functionality of the fabrication process. This reduces the need for specialized high-cost processing steps while achieving superior capacitance density.
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
This configuration optimizes capacitance density and maintains chip area efficiency while providing improved capacitance and resistance characteristics suitable for high-frequency applications, addressing the limitations of traditional MOM structures.
Implementation Method 1
a capacitor disposed over the surface of the substrate, the capacitor having an anode component that includes a plurality of first conductive stacks and a cathode component that includes a plurality of second conductive stacks
Implementation Method 2
utilizing dielectric material for enhanced capacitance without increasing chip space
Data Source
AI summary
The present disclosure provides a semiconductor device. The semiconductor device includes a substrate that spans in an X-direction and a Y-direction that is orthogonal to the X-direction. The semiconductor device includes an interconnect structure formed over the substrate in a Z-direction that is orthogonal to both the X-direction and the Y-direction. The interconnect structure includes a plurality of metal lines interconnected together in the Z-direction by a plurality of vias. The interconnect structure contains a capacitor that includes an anode component and a cathode component. The anode component includes an array of elongate anode stack elements extending in the Z-direction. The cathode component includes an array of elongate cathode stack elements extending in the Z-direction. The array of anode stack elements are interdigitated with the array of cathode stack elements in both the X direction and the Y direction.