Low-k Material Self-Limited Etching for Selective Residue Removal
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Solution Overview
Problem
Conventional etching processes for semiconductor materials, such as silicon-containing materials, often cause damage to other materials on the substrate and leave residues like carbon and nitrogen, which impact the performance of advanced transistor structures like GAA transistors.
Innovation Solution
A method involving plasma effluents of hydrogen- and nitrogen-containing precursors is used to treat silicon-containing materials, reducing carbon and nitrogen concentrations, followed by a self-limiting etch process that selectively removes the treated portion of the material, minimizing damage to other materials on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching processes are used to remove silicon-containing materials, then material removal is achieved, but damage is caused to other materials on the substrate and carbon/nitrogen residues remain
Solution Approach 1:
The patent applies preliminary action by treating the silicon-containing material with plasma effluents containing hydrogen- and nitrogen-containing precursors before etching. This pre-treatment modifies the material surface, making it more susceptible to selective etching while protecting other materials, thereby enabling effective material removal without causing damage or residue contamination.
Solution Approach 2:
The patent utilizes parameter changes by controlling the plasma processing conditions, including precursor composition, pressure, and power levels, to achieve selective modification of the silicon-containing material. By optimizing these parameters, the process enables selective etching that removes the target material while preserving other materials and minimizing residue.
2Manufacturing precision
If wet HF etching is used to preferentially remove silicon oxide, then selectivity is improved, but penetration into constrained trenches is difficult and material deformation occurs
Solution Approach 1:
The patent replaces the wet chemical etching mechanism with a plasma-based etching process. This substitution allows the etching to occur through reactive species in the plasma phase, enabling better penetration into constrained trenches and reducing material deformation while maintaining selectivity through controlled chemical reactions.
Solution Approach 2:
The patent changes the physical state of the etching medium from liquid to plasma phase, and controls parameters such as gas composition, pressure, and RF power to achieve both high selectivity and effective trench penetration without material deformation.
3Ease of operation
If local plasma is used to penetrate constrained trenches and reduce material deformation, then trench penetration and material integrity are improved, but substrate damage occurs through electric arc discharge
Solution Approach 1:
The patent introduces an intermediary step by using plasma effluents containing hydrogen- and nitrogen-containing precursors to treat the silicon-containing material before etching. This intermediary treatment modifies the material surface properties, enabling subsequent etching to proceed without requiring high-power local plasma that would cause electric arc discharge and substrate damage.
Solution Approach 2:
The preliminary plasma treatment with specific precursors prepares the silicon-containing material for selective etching, reducing the need for aggressive plasma conditions that would cause substrate damage while still achieving effective trench penetration and material integrity.
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 selective etching of silicon-containing materials with reduced damage and contamination, improving the performance of GAA structures by maintaining the integrity of other materials on the substrate.
Implementation Method 1
forming plasma effluents of the hydrogen-containing precursor and the nitrogen-containing precursor
Implementation Method 2
contacting the substrate with plasma effluents of the hydrogen-containing precursor and the nitrogen-containing precursor. The contacting may reduce a carbon concentration, a nitrogen concentration, or both in a portion of the layer of the silicon-containing material
Implementation Method 3
providing one or more etchant precursors to the processing region. The methods may include contacting the substrate with the one or more etchant precursors. The contacting may remove the portion of the layer of the silicon-containing material
Data Source
AI summary
Exemplary semiconductor processing methods may include providing a hydrogen-containing precursor and a nitrogen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be disposed within the processing region. The substrate may include a layer of a silicon-containing material. The methods may include forming plasma effluents of the hydrogen-containing precursor and the nitrogen-containing precursor. The methods may include contacting the substrate with plasma effluents of the hydrogen-containing precursor and the nitrogen-containing precursor. The contacting may reduce a carbon concentration, a nitrogen concentration, or both in a portion of the layer of the silicon-containing material. The methods may include providing one or more etchant precursors to the processing region. The methods may include contacting the substrate with the one or more etchant precursors. The contacting may remove the portion of the layer of the silicon-containing material.