Boron Etchant Residue Removal for Selective Semiconductor Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching processes face challenges in selectively removing certain materials without causing damage or deformation, particularly in high aspect ratio features, and often leave residues that contaminate the substrate.
Innovation Solution
A boron-containing etchant precursor is used in a plasma-free process, combined with hydrogen-containing and optionally oxygen-containing precursors, to selectively remove materials while minimizing etch byproducts, using controlled flow rates and temperatures to maintain substrate integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet etching is used to remove oxide dielectrics, then etching speed is improved, but penetration into constrained trenches is poor and material deformation occurs
Solution Approach 1:
The patent replaces conventional wet chemical etching with a plasma-based etching process. The plasma etchant (containing fluorine atoms) provides chemical reaction capability similar to wet etching but delivers it through a gas phase mechanism that can penetrate constrained trenches effectively while maintaining material integrity through controlled reaction kinetics and physical sputtering components.
Solution Approach 2:
The patent changes the physical state of the etchant from liquid (wet etching) to gas phase plasma. This parameter change enables the etchant to reach into high aspect ratio trenches through gas flow and diffusion, while the plasma state provides directional control and reduced material deformation through controlled ion bombardment and reaction kinetics.
2Manufacturing precision
If dry plasma etching is used to penetrate constrained trenches, then trench penetration is improved, but substrate damage occurs due to electric arcs
Solution Approach 1:
The patent uses a plasma environment controlled with specific gas compositions (containing fluorine-containing precursors) that creates a chemically controlled etching atmosphere. This controlled plasma environment prevents uncontrolled electric arc formation while maintaining effective trench penetration through directed ion bombardment and chemical reaction.
Solution Approach 2:
The patent replaces conventional plasma etching that relies on high power RF fields (prone to arc discharge) with a plasma-free or low-plasma environment using chemically reactive precursors. This substitution maintains trench penetration capability through chemical vapor deposition and reaction mechanisms while eliminating the harmful electric arc damage to the substrate.
3Manufacturing precision
If selective etching is performed to remove one material faster than another, then etch selectivity is improved, but etch byproduct residue remains on surfaces
Solution Approach 1:
The patent extracts or removes etch byproduct residues from surfaces using a separate cleaning step with hydrogen-containing precursors. This secondary process specifically targets and removes boron-containing byproducts from the etching reaction, leaving the etched structures clean without affecting the selectivity achieved in the primary etching step.
Solution Approach 2:
The patent introduces hydrogen-containing precursors as an intermediary cleaning agent that reacts with boron-containing byproducts to form volatile compounds. This intermediary substance facilitates the removal of residues without interfering with the selective etching process, effectively separating the etching and cleaning functions.
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 allows for efficient, residue-free etching of high aspect ratio features, protecting substrate materials and preventing contamination, thereby enhancing etch rates and selectivity.
Implementation Method 1
contacting the substrate with the boron-containing etchant precursor and the hydrogen-containing precursor. This approach allows for efficient, residue-free etching of high aspect ratio features
Implementation Method 2
The processing region may be maintained plasma-free. A temperature may be maintained at greater than or about 50° C.
Data Source
AI summary
Exemplary semiconductor processing methods may include providing a boron-containing etchant precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. The methods may include providing a hydrogen-containing precursor, helium, or both to the processing region with the boron-containing etchant precursor. The methods may include contacting the substrate with the boron-containing etchant precursor and the hydrogen-containing precursor. The methods may include selectively removing at least a portion of a first material on the substrate relative to a second material second material on the substrate while removing an etch byproduct from one or more surfaces of the processing region.