STI Buried Interconnect Layout for Compact Semiconductor Transistors
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Solution Overview
Problem
The challenge of reducing area, power consumption, and noise in integrated circuits while improving performance is exacerbated by the need for larger diffusion areas due to photolithographic misalignment, leading to increased capacitances and heat dissipation issues as transistor dimensions shrink, which are not effectively addressed by existing heat dissipation methods.
Innovation Solution
The implementation of a semiconductor device structure with an interconnection structure under the STI region, using epitaxial semiconductor material and asymmetric spacers, and a connecting plug to connect to the first interconnection layer, along with a trench within the active region, to facilitate signal delivery and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If contact holes are formed outside the source/drain regions due to photolithographic misalignment, then alignment is achieved, but diffusion area and die area increase
Solution Approach 1:
The patent moves the interconnection structure from the traditional planar surface level to an underground dimension within the STI region. By forming conductive interconnections below the original semiconductor surface, the patent eliminates the need for large contact holes and achieves self-aligned connections without increasing diffusion area, thus resolving the contradiction between alignment precision and area consumption.
Solution Approach 2:
The patent introduces an intermediate STI region as a mediator to house the underground interconnection structure. This STI-based interconnection layer acts as an intermediary between the transistor active region and the upper metal interconnection layers, enabling signal transmission without requiring large surface contact areas and thus reducing both diffusion area and die area.
2Productivity
If transistor dimensions are shrunk to meet scaling requirements, then device density increases, but heat dissipation capability deteriorates
Solution Approach 1:
The patent utilizes the vertical dimension by placing interconnection structures underground within the STI region. This three-dimensional architecture allows heat to be conducted away from the transistor junction through the STI region and substrate in the vertical direction, improving heat dissipation capability as transistor dimensions are shrunk and integration density increases.
3Manufacturing precision
If larger diffusion areas are used to accommodate contact holes, then alignment tolerance is achieved, but capacitance and power consumption increase
Solution Approach 1:
The patent extracts the interconnection function from the traditional surface-level contact hole structure and relocates it to an underground position within the STI region. This separation allows the diffusion area to be minimized to only what is necessary for the active transistor region, eliminating the need for enlarged diffusion areas for alignment tolerance, thus reducing capacitance and power consumption.
4Temperature
If conventional heat dissipation methods are applied, then some cooling effect is achieved, but cost and effectiveness deteriorate
Solution Approach 1:
The patent merges the interconnection function with the heat dissipation function by integrating the underground interconnection structure within the STI region. The same STI structures that provide electrical isolation also serve as thermal conduction paths, eliminating the need for separate expensive heat dissipation components and achieving cost-effective thermal management.
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 approach reduces the area penalty, enhances heat dissipation, and improves signal delivery efficiency, addressing the limitations of existing technologies in scaling down integrated circuits and enhancing chip performance.
Implementation Method 1
The first conductive region includes an epitaxial semiconductor material. The epitaxial semiconductor material of the first conductive region is over a top surface of the connecting plug, or the connecting plug is within the STI region and the epitaxial semiconductor material of the first conductive region is connected to a first sidewall of the connecting plug.
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
Semiconductor device structures are provided. The semiconductor device structure includes a semiconductor substrate with an original semiconductor surface and an active region, a STI region surrounding the active region, a transistor formed based on the active region and including a gate structure, a first conductive region, a second conductive region and a channel region between the first and second conductive regions, an interconnection structure extending beyond the transistor, and a connecting plug electrically connecting the interconnection structure to the first conductive region of the transistor. The first conductive region includes an epitaxial semiconductor material. The interconnection structure is disposed under the original semiconductor surface and within the STI region.