SiGe Etching with Remote Plasma for Low Surface Roughness
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Solution Overview
Problem
Conventional etching processes struggle to uniformly recess silicon-and-germanium-containing materials due to residue formation, leading to increased surface roughness and affecting the electrical and mechanical properties of semiconductor devices.
Innovation Solution
A semiconductor processing method involving a pre-treatment precursor in a remote plasma system to remove residue from silicon-and-germanium-containing materials, followed by a post-treatment precursor to oxidize and remove portions of the material, resulting in improved surface roughness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used on silicon-and-germanium-containing materials, then the etching can be performed, but residue forms on the material surface leading to increased surface roughness
Solution Approach 1:
A pre-treatment precursor is introduced before the main etching process to prepare the silicon-and-germanium-containing material surface. This preliminary action modifies the surface properties to prevent residue formation during subsequent etching, thereby maintaining low surface roughness throughout the process.
Solution Approach 2:
The patent introduces a post-treatment precursor that oxidizes the etched surface, changing the chemical state of the material. This parameter change (oxidation) allows for removal of rough portions and control of surface morphology, reducing surface roughness after etching.
2Manufacturing precision
If wet HF etching is used, then silicon oxide can be removed preferentially, but the process cannot penetrate constrained trenches and may deform remaining material
Solution Approach 1:
The patent replaces wet chemical etching with a plasma-based etching process. This substitution allows the etching to penetrate constrained trenches effectively while maintaining selectivity through controlled plasma chemistry, avoiding the limitations of wet HF etching.
3Ease of operation
If dry plasma etching is used, then constrained trenches can be penetrated and deformation is reduced, but substrate damage occurs through electric arcs
Solution Approach 1:
The patent uses a remote plasma source as an intermediary, generating plasma in a separate region and transporting reactive species to the substrate. This intermediary approach maintains the penetration capability of plasma etching while eliminating direct arc contact with the substrate, preventing substrate damage.
Solution Approach 2:
The patent segments the plasma generation and substrate processing into separate spatial zones. Plasma is generated in a remote region and the reactive species are transported to the substrate area, separating the high-energy plasma generation from the delicate substrate processing to avoid damage.
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
The method achieves a reduced average surface roughness of less than 5 nm, enhancing the uniformity and quality of etched silicon-and-germanium-containing materials, thereby improving the electrical and mechanical properties of semiconductor devices.
Implementation Method 1
generating plasma effluents of the pre-treatment precursor in the remote plasma system
Implementation Method 2
contacting the substrate with the post-treatment precursor. The contacting may oxidize a portion of the silicon-and-germanium-containing material
Data Source
AI summary
Exemplary semiconductor processing methods may include providing a pre-treatment precursor to a processing a remote plasma system of a semiconductor processing chamber. The methods may include generating plasma effluents of the pre-treatment precursor in the remote plasma system. The methods may include flowing plasma effluents of the pre-treatment precursor to a processing region of the semiconductor processing chamber. A substrate including alternating layers of material may be disposed within the processing region. The alternating layers of material may include a silicon-and-germanium-containing material. The methods may include contacting the substrate with the plasma effluents of the pre-treatment precursor. The methods may include etching the silicon-and-germanium-containing material. The methods may include providing a post-treatment precursor to the processing region. The methods may include contacting the substrate with the post-treatment precursor. The methods may include removing the portion of the silicon-and-germanium-containing material.