Atomic Layer Etching for Nanowire Surface Planarization
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Solution Overview
Problem
Conventional semiconductor processing methods, such as chemical mechanical polishing, struggle to achieve precise planarization of surfaces with nanometer-scale roughness in superconducting and semiconductor devices due to the complexity and thinness of layers, leading to damaged layers and integration issues.
Innovation Solution
The method employs atomic layer etching using a low-power chlorine and argon plasma to form a reactive layer on the dielectric layer, with argon ions gently accelerated to etch protrusions laterally, achieving quasi-conformal nano-planarization and minimizing surface roughness to less than 5 nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical mechanical polishing is used to planarize surfaces, then surface smoothness can be improved, but the thinness and complexity of nanometer-scale layers are damaged and integration issues occur
Solution Approach 1:
The patent replaces conventional mechanical chemical mechanical polishing with a plasma-based atomic layer etching process. Low-power chlorine and argon plasma are used to form a reactive layer on the dielectric surface, followed by gentle ion acceleration that etches protrusions laterally through sidewalls. This chemical-plasma based approach substitutes the mechanical polishing action, achieving nanometer-scale planarization (surface roughness < 5 nm) without the mechanical contact that damages thin superconducting and semiconductor layers.
2Reliability
If low-power plasma is used for atomic layer etching, then layer integrity is maintained, but etching speed may be reduced
Solution Approach 1:
The atomic layer etching process employs periodic cyclic action with distinct phases: first, low-power chlorine plasma forms a reactive layer on the dielectric surface; then argon plasma with gentle ion acceleration etches the reactive layer. This periodic alternation between reactive layer formation and selective etching phases enables controlled material removal while maintaining layer integrity. The cyclic nature of the process allows precise control over etching depth and surface morphology, achieving planarization without damaging underlying thin layers.
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 effectively removes protrusions and roughness, enabling precise planarization and improved integration of subsequent layers in multilayer devices, enhancing the fabrication and performance of superconducting and semiconductor devices by maintaining the integrity of thin metal wires and dielectric layers.
Implementation Method 1
reacting a surface of the dielectric layer with a reactant, comprising a gas or a plasma, to form a reactive layer on the dielectric layer
Implementation Method 2
the reactive layer comprises a chemical compound including the reactant and elements of the dielectric layer
Implementation Method 3
accelerating ions onto the surface so that a majority of the ions impact the surface at an angle of at least 10 degrees with respect to a surface normal
Implementation Method 4
the etching comprises chemical sputtering
Implementation Method 5
sufficient to act as a catalyst for the re-arrangement
Data Source
AI summary
A method for etching a surface including obtaining a structure comprising a plurality of nanowires on or above a substrate and a dielectric layer on or above the nanowires, wherein the dielectric layer comprises protrusions formed by the underlying nanowires; reacting a surface of the dielectric layer with a reactant, comprising a gas or a plasma, to form a reactive layer on the dielectric layer, wherein the reactive layer comprises a chemical compound including the reactant and elements of the dielectric layer and the reactive layer comprises sidewalls defined by the protrusions; and selectively etching the reactive layer, wherein the etching etches the protrusions laterally through the sidewalls so as to planarize the surface and remove or shrink the protrusions.