Selective Semiconductor Etching with Plasma Reduction and Halogen Species
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Solution Overview
Problem
Existing etching processes struggle to selectively etch multiple materials on semiconductor substrates with precise control over etching rates, especially when different materials need to be etched at varying rates on the same substrate.
Innovation Solution
A method involving hydrogen-containing plasma and remotely-generated reactive halogen species is used to selectively etch etchable materials relative to non-etchable materials on a substrate, with controlled etching depths achieved through sequential reaction steps and plasma generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong reactivity is used from etchants to etch dielectric and metal oxide materials, then etching capability is improved, but control of etching rate deteriorates
Solution Approach 1:
The etching process is divided into two distinct sequential steps: (1) a reduction step using hydrogen-containing plasma to reduce the etchable material to a predetermined depth, and (2) an etching step using remotely-generated reactive halogen species to selectively etch the reduced material. This segmentation allows independent optimization of each step's parameters, achieving both strong etching capability and precise rate control.
Solution Approach 2:
The hydrogen-containing plasma reduction step is performed as a preliminary action before the actual etching step. This preliminary reduction modifies the material surface properties and creates a controlled layer that is then selectively removed in the subsequent etching step, enabling precise control over the final etching rate while maintaining strong etching capability.
2Adaptability or versatility
If selective etching of multiple materials is achieved, then manufacturing versatility is improved, but process complexity increases
Solution Approach 1:
The two-step process using hydrogen-containing plasma followed by reactive halogen species demonstrates universal applicability across multiple material types including silicon oxide, silicon oxycarbide, silicon nitride, and transition metal oxides. The same fundamental process sequence achieves selective etching of different materials by adjusting parameters, providing multi-functionality without requiring entirely different process chemistries for each material.
Solution Approach 2:
Selective etching of different materials is achieved by changing process parameters such as hydrogen plasma power, reactive halogen species concentration, temperature, and exposure times rather than changing the fundamental process mechanism. This allows one process platform to handle multiple materials with different selectivity requirements.
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
Enables precise and selective etching of multiple materials on semiconductor substrates, allowing for differential etching rates and improved scalability in semiconductor device manufacturing.
Implementation Method 1
providing hydrogen-containing plasma into the reaction chamber to reduce the etchable material to a predetermined depth
Implementation Method 2
providing remotely-generated reactive halogen species and hydrogen into the reaction chamber to selectively etch the reduced etchable material
Implementation Method 3
providing hydrogen-containing plasma into the reaction chamber
Data Source
AI summary
The current disclosure relates to methods of selectively etching material from a first surface of a substrate relative to a second surface of the substrate. The method includes providing the substrate having a first surface comprising an etchable material, and a second surface comprising a non-etchable material in a reaction chamber, providing hydrogen-containing plasma into the reaction chamber to reduce the etchable material to a predetermined depth; and providing remotely-generated reactive halogen species and hydrogen into the reaction chamber to selectively etch the reduced etchable material. The disclosure further relates to methods of selectively etching at least two different etchable materials simultaneously from a surface of a substrate relative to a non-etchable material on the same substrate, to methods of simultaneous differential etching of three or more etchable materials on a substrate, as well as to assemblies for processing semiconductor substrates.