Directional Metal Oxide Etching via Oxy-Fluoride Surface Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor etching processes face challenges in achieving selective and directional removal of metal-containing films, particularly high-k dielectric materials like metal oxides, which can lead to reduced etch selectivity and increased damage to surrounding materials.
Innovation Solution
The proposed method involves modifying the exposed surface of a metal oxide layer on a substrate to produce a modified portion, which is then contacted with a fluorine-containing precursor to form a metal oxy-fluoride material. This is followed by contacting the metal oxy-fluoride with a chlorine-containing precursor, allowing for controlled removal of the metal oxy-fluoride material while maintaining selectivity and protecting underlying structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to remove metal oxide, then the etching process is simple and can remove oxide dielectrics effectively, but the process cannot penetrate constrained trenches and may deform remaining material
Solution Approach 1:
The patent transitions from wet etching to dry etching, changing the physical state of the etching medium from liquid to gas. This parameter change enables penetration into constrained trenches while maintaining etching effectiveness, and prevents deformation of remaining material through controlled gas-phase chemical reactions
Solution Approach 2:
The patent replaces the chemical mechanism of wet etching with a plasma-based dry etching mechanism. The plasma provides reactive species that chemically react with metal oxide to form volatile products, eliminating the need for liquid etchants and enabling precise directional etching without material deformation
2Manufacturing precision
If dry etching with local plasma is used to etch metal oxide, then the process can penetrate constrained trenches and exhibits less deformation, but the plasma may damage the substrate through electric arcs
Solution Approach 1:
The patent introduces a photoresist mask as an intermediary layer between the plasma and the substrate. This mask selectively protects regions of the substrate from plasma exposure, allowing precise pattern transfer while preventing direct plasma-substrate interaction that would cause damage from electric arcs
Solution Approach 2:
The patent applies plasma etching locally only to exposed regions through photolithographic patterning. The photoresist mask creates spatially selective etching zones, confining plasma interaction to specific areas and preventing widespread substrate damage while achieving precise trench penetration where needed
3Productivity
If conventional etching processes are used on metal-containing films, then the process can remove material, but the etch selectivity is reduced and surrounding materials are damaged
Solution Approach 1:
The patent performs preliminary patterning of the photoresist mask before etching. This preliminary action defines precise etch regions, ensuring that subsequent plasma etching only affects intended metal oxide areas while protecting surrounding materials, thereby maintaining high etch selectivity and preventing collateral damage
Solution Approach 2:
The patent segments the etching process into distinct stages: photoresist deposition, photolithographic patterning, and controlled plasma etching. This segmentation allows each step to be optimized independently, achieving both high material removal rates and precise selectivity control by separating pattern definition from material removal
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 enables a directional dry etching process that protects substrate features, increases the etch rate of metal-containing films relative to other materials, and provides selective removal of metal oxides, thereby addressing integration challenges and improving the quality of semiconductor devices.
Implementation Method 1
contacting the modified portion of metal oxide with a fluorine-containing precursor. The contacting may produce a metal oxy-fluoride material
Implementation Method 2
contacting the metal oxy-fluoride material with the etchant precursor. The etchant precursor may be or include a chlorine-containing precursor
Implementation Method 3
forming a plasma of an oxygen-containing precursor to produce oxygen-containing plasma effluents. The plasma effluents may cause a portion of metal oxide to become amorphous metal oxide
Data Source
AI summary
Exemplary etching methods may include modifying an exposed surface of a layer of metal oxide on a substrate housed in a processing region of a semiconductor processing chamber to produce a modified portion of metal oxide. The methods may include contacting the modified portion of metal oxide with a fluorine-containing precursor. The contacting may produce a metal oxy-fluoride material. The methods may include flowing an etchant precursor into the processing region. The methods may include contacting the metal oxy-fluoride material with the etchant precursor. The methods may include removing the metal oxy-fluoride material.