High-Aspect-Ratio Etching With Passivation for Vertical Profiles
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Solution Overview
Problem
Conventional etch processes for creating high aspect ratio structures in semiconductor manufacturing fail to achieve desired vertical profiles, leading to poor device performance or failure.
Innovation Solution
An iterative etching method involving a passivation layer and treatment is employed to maintain vertical profiles, using plasma-assisted etching with specific gas mixtures and controlled etch processes to achieve high aspect ratios of 100:1 or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional single etch process is used to achieve deep structure, then etch depth is improved, but vertical profile deteriorates
Solution Approach 1:
The etch process is divided into multiple sequential etch operations with intermediate passivation layer depositions. Each etch operation etches to a specific depth, then a passivation layer is deposited to protect the etched portion. This segmentation allows achieving deep structures while maintaining vertical profiles by controlling each segment separately.
Solution Approach 2:
A passivation layer is deposited on the sidewalls before the next etch operation begins. This preliminary action protects the sidewalls from damage during subsequent etching, ensuring that the vertical profile is maintained as the etch depth increases through multiple operations.
2Length of moving object
If repeated etch processes are used to achieve desired depth, then etch depth is improved, but device performance deteriorates
Solution Approach 1:
The repeated etch processes are segmented into controlled operations with intermediate passivation steps. This segmentation prevents the cumulative damage that would occur with continuous etching, thereby maintaining device performance while achieving the required etch depth through multiple controlled operations.
Solution Approach 2:
The passivation layer is deposited as a preliminary protective action between etch operations. This prevents sidewall damage and structural degradation that would otherwise accumulate through repeated etching, thus preserving device performance while enabling deeper etching.
3Length of moving object
If etch process is used to achieve high aspect ratio, then aspect ratio is improved, but manufacturing precision deteriorates
Solution Approach 1:
The etch process is segmented into multiple operations, each etching to a controlled depth with intermediate passivation. This segmentation allows precise control of the vertical profile at each stage, maintaining manufacturing precision even as the overall aspect ratio increases through cumulative etching.
Solution Approach 2:
The passivation layer is deposited as a preliminary protective measure before each subsequent etch operation. This preliminary action maintains the vertical profile integrity and prevents variation, enabling high aspect ratio structures to be manufactured with precise dimensional control.
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 method results in high aspect ratio structures within a 10 nanometer tolerance, increasing yield, reducing waste, and enhancing processing efficiency and cost-effectiveness.
Implementation Method 1
etching the substrate comprises generating a plasma from a gas mixture of Cl2, HBr, O2, and Ar, and exposing the substrate to the plasma for about 10 seconds to about 200 seconds
Implementation Method 2
oxidizing the sidewalls of the recess and the inner sidewalls of the mask layer by exposing the substrate to a generated oxygen plasma for about 10 seconds to about 20 seconds
Data Source
AI summary
A method and system for etching high aspect ratio structures in a semiconducting processing chamber are disclosed herein. In one example, a method of patterning a substrate comprises etching the substrate to form a recess, depositing a passivation layer on sidewalls of the recess, treating the passivation layer, and etching the recess to a second depth. The substrate etch forms a recess to a first depth, the substrate having a mask layer disposed thereon. The treating of the passivation layer is for removal of a clogging material formed from an etch byproduct on the mask layer. The etching the recess to a second depth while maintaining a minimum variation of a recess sidewall width.