High Aspect Ratio Semiconductor Sidewall Reinforcement
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Solution Overview
Problem
High aspect ratio structures in semiconductor devices face challenges such as uneven etching rates and mechanical fragility due to Aspect Ratio Dependent Etching (ARDE) and thermal expansion issues, which affect the stability and uniformity of etching and layer deposition processes.
Innovation Solution
The semiconductor device features electric elements with sidewall surfaces that include angled sections forming inner corners at a constant distance for mechanical reinforcement, ensuring uniform etching and layer deposition rates, and extending over the surface to facilitate thermal conductivity and reduce stress, with embodiments including arc, interdigitated, and zigzag patterns for enhanced structural strength and surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If pores or trenches are etched into the substrate to increase surface area, then the surface area increases, but the etching rate becomes uneven and etching time increases due to Aspect Ratio Dependent Etching (ARDE)
Solution Approach 1:
The patent divides the high aspect ratio structure into multiple lower aspect ratio segments by creating stepped terraces at regular intervals along the depth of the pore or trench. Each terrace has a larger cross-sectional area than the section below it, creating a segmented structure that reduces the effective aspect ratio of each etching step while maintaining the overall high surface area. This segmentation allows etchant to reach all surfaces more effectively, eliminating ARDE effects and achieving uniform etching across all terraces.
2Manufacturing precision
If pillars are used instead of pores to improve etchant diffusion, then etching uniformity improves, but mechanical stability deteriorates as pillars are more fragile and likely to break
Solution Approach 1:
The patent creates stepped terraces that segment the high aspect ratio structure into multiple lower aspect ratio sections. Each terrace is supported by the structure below it, creating a cascading support system that significantly enhances mechanical stability. The stepped geometry distributes mechanical loads across multiple levels rather than concentrating stress at a single point, making the structure more resistant to breaking during handling and processing while maintaining good etching uniformity.
3Area of moving object
If pillars are arranged in an array to increase surface area, then surface area increases, but thermal expansion causes damage especially near the periphery where symmetry is disrupted
Solution Approach 1:
The stepped terrace structure segments the pillar array into multiple levels, with each terrace providing a platform that distributes thermal stresses across a larger area. The cascading geometry creates natural stress distribution paths that accommodate thermal expansion more uniformly, particularly at the periphery where symmetry is naturally disrupted. Each terrace acts as a stress-dissipating element that reduces the concentration of thermal stresses.
4Productivity
If high aspect ratio structures are used to achieve high density, then device density increases, but mechanical robustness decreases making devices more susceptible to damage
Solution Approach 1:
The patent segments the high aspect ratio structure into multiple stepped terraces, where each terrace provides mechanical support to the sections above it. This segmentation creates a self-supporting cascading structure that maintains the high density benefit of high aspect ratio features while dramatically improving mechanical robustness. The stepped geometry distributes mechanical loads across multiple levels, preventing the structure from being overly susceptible to damage during handling and processing.
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 results in more robust, uniformly etched, and thermally stable high aspect ratio structures with reduced stress and improved layer deposition, leading to higher device yields and enhanced mechanical stability, suitable for applications like capacitors and micro batteries.
Implementation Method 1
the sidewall surface comprises a first section and a second section adjoining the first section along a line extending substantially parallel to the first direction, wherein the first and second sections are placed at an angle with respect to each other for providing an inner corner, wherein the sidewall surface at the inner corner is, at least partially, arranged at a constant distance R from a facing part of the second element for providing a mechanical reinforcement structure at the inner corner
Implementation Method 2
the larger amount of free space around the pillars on the substrate enables a greater degree of diffusion of an etchant
Implementation Method 3
extending over the surface to facilitate thermal conductivity and reduce stress
Data Source
AI summary
The invention relates to an semi-conductor device comprising a first surface and neighboring first and second electric elements arranged on the first surface, in which each of the first and second elements extends from the first surface in a first direction, the first element having a cross section substantially perpendicular to the first direction and a sidewall surface extending at least partially in the first direction, wherein the sidewall surface comprises a first section and a second section adjoining the first section along a line extending substantially parallel to the first direction, wherein the first and second sections are placed at an angle with respect to each other for providing an inner corner wherein the sidewall surface at the inner corner is, at least partially, arranged at a constant distance R from a facing part of the second element for providing a mechanical reinforcement structure at the inner corner.