Bottom Isolation Formation via Selective Fluorine Plasma Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor processing methods face challenges in forming high-quality semiconductor structures with effective current leakage prevention and defect-free source/drain formation, often requiring reactive-ion etching (RIE) and ion implantation operations that can damage substrates and introduce defects.
Innovation Solution
A method involving selective etching and deposition processes in a remote plasma system, forming a bottom insulation layer without extending into source or drain regions, using a fluorine-containing precursor plasma to recess silicon-containing materials and deposit spacer materials selectively, thereby avoiding RIE and ion implantation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RIE and ion implantation operations are used to form bottom insulation layer, then current leakage prevention is improved, but substrate damage and defect introduction increase
Solution Approach 1:
The patent changes the etching parameters by using a remote plasma source with fluorine-containing precursors instead of conventional RIE, and controls the etching conditions to achieve selective removal of silicon-containing materials without damaging the substrate. This parameter change allows effective current leakage prevention while minimizing substrate damage
Solution Approach 2:
The patent introduces a remote plasma source as an intermediary between the etching chemistry and the substrate. The remote plasma generates fluorine-containing species that selectively etch silicon-containing materials without direct ion bombardment, thus preventing substrate damage while still forming the bottom insulation layer effectively
2Object-affected harmful factors
If selective etching and deposition processes are used in remote plasma system, then substrate damage is reduced, but process complexity increases
Solution Approach 1:
The patent combines selective etching and deposition processes into a unified remote plasma system workflow. By integrating these processes and using automated sequence control, the system manages complexity while maintaining the benefits of reduced substrate damage through selective material removal and spacer formation
3Manufacturing precision
If conventional masking and removal operations are performed, then manufacturing precision is improved, but process queue time increases
Solution Approach 1:
The patent extracts and eliminates unnecessary masking and removal operations from the conventional process sequence. By using selective etching that inherently defines the desired patterns without requiring additional masking steps, the process achieves comparable manufacturing precision while significantly reducing process queue time
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 prevents current leakage through bottom nanowire channels without hindering source or drain formation, reduces defects, and minimizes damage to substrates, while also reducing process queue times by eliminating unnecessary masking and removal operations.
Implementation Method 1
forming a plasma of a fluorine-containing precursor in a remote plasma region of a processing chamber
Implementation Method 2
contacting a semiconductor substrate with effluents of the plasma... The layers of the third silicon-containing material may be selectively recessed relative to the layer of the first silicon-containing material
Implementation Method 3
depositing a spacer material adjacent to the layers of the third silicon-containing material... The spacer material may be selectively deposited adjacent to the layers of the third silicon-containing material relative to exposed regions of the layer of the first silicon-containing material
Implementation Method 4
etching the layer of the first silicon-containing material... The layer of the first silicon-containing material may be selectively etched relative to the layers of the second silicon-containing material and the spacer material
Data Source
AI summary
A method may include forming a plasma of a fluorine-containing precursor and contacting a semiconductor substrate with plasma effluents. The semiconductor substrate may include a layer of a first silicon-containing material having a first germanium content formed over the semiconductor substrate, and alternating layers of a second silicon-containing material and a third silicon-containing material over the layer of the first silicon-containing material. The third silicon-containing material may have a second germanium content. The method may further include laterally recessing the third silicon-containing material relative to the first and second silicon-containing materials. The method may further include depositing a spacer material adjacent to the third silicon-containing material relative to the first and second silicon-containing materials. The method may also include etching the first silicon-containing material relative to the second silicon-containing material and the spacer material.