Silicon Etching with Pnictogen-Halogen Cycles for Low Thermal Budget
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Solution Overview
Problem
There is a growing need for novel material removal techniques in semiconductor manufacturing that can selectively etch specific materials efficiently, even in intricate device geometries, with a focus on silicon-containing materials, to address the challenges of precision and thermal budget constraints.
Innovation Solution
A method involving the use of pnictogen-containing and halogen-containing gaseous reactants in a process chamber to etch silicon-containing materials, with controlled temperature and cyclic processes, enabling precise and selective etching with reduced thermal impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to remove silicon-containing materials, then material removal is achieved, but selectivity and precision are insufficient for intricate device geometries
Solution Approach 1:
The patent employs a two-step etching process with distinct parameter sets: first using a pnictogen-containing gas (e.g., NF3, N2O) at controlled temperature to selectively modify silicon-containing materials, then using a halogen-containing gas (e.g., CF4, Cl2) to etch the modified material. This parameter differentiation enables precise control over etching selectivity and rate, achieving high precision for intricate geometries while maintaining versatility across different silicon-based materials
Solution Approach 2:
The patent introduces a pnictogen-containing gas as an intermediary substance that temporarily modifies the silicon-containing material before the actual etching step. This intermediary modification layer enhances subsequent halogen-based etching while protecting non-silicon materials, thereby improving both selectivity for silicon-containing materials and precision in defining device patterns
2Productivity
If high temperature etching is used to increase etching rate, then productivity improves, but thermal degradation of the substrate occurs
Solution Approach 1:
The patent segments the etching process into two distinct temperature-controlled steps: a low-temperature modification step using pnictogen gas to prepare the silicon-containing material surface, followed by a controlled etching step using halogen gas. This segmentation allows each step to operate at optimal temperatures, achieving adequate etching rates while preventing substrate thermal degradation that would occur in single high-temperature processes
Solution Approach 2:
The patent replaces thermal energy-driven etching with a chemical reaction-based etching mechanism using pnictogen and halogen gases. This substitution enables material removal through selective chemical reactions rather than thermal processes, maintaining productivity through controlled reaction rates while eliminating the harmful thermal degradation associated with conventional high-temperature etching
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 high precision and selectivity in etching silicon-containing materials, reducing thermal degradation and facilitating the formation of high-quality epitaxial layers with minimal thermal budget.
Implementation Method 1
providing a pnictogen-containing gaseous reactant in the process chamber such that the silicon-containing material is exposed to the pnictogen-containing gaseous reactant to form a modified silicon-containing material
Implementation Method 2
providing a halogen-containing gaseous reactant in the process chamber such that the modified silicon-containing material is exposed to the halogen-containing gaseous reactant to at least partly etch the modified silicon-containing material
Data Source
AI summary
This disclosure relates to a method and device for etching a substrate as well as a method and apparatus for processing a substrate. The method for etching a substrate comprises providing a substrate comprising a silicon-containing material in a process chamber and etching the silicon-containing material at least partly. The process of etching the silicon-containing material comprises providing a pnictogen-containing gaseous reactant in the process chamber and providing a halogen-containing gaseous reactant in the process chamber. The method for processing a substrate comprises pre-cleaning the substrate to form a cleaned substrate and forming an epitaxial layer on the cleaned substrate.