Tin Oxide Spacer Etching for Precise Sidewall Patterning
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in precisely patterning and forming small-scale features using spacers, as current materials and etching techniques lack sufficient etch selectivity and control, particularly when forming tin oxide spacers and hardmasks.
Innovation Solution
The use of tin oxide films in semiconductor processing, combined with selective etching methods using hydrogen-, chlorine-, and fluorocarbon-based chemistries, allows for the precise removal of tin oxide from horizontal surfaces while preserving it on sidewalls, enabling the formation of spacers and hardmasks with high etch selectivity and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching techniques are used to remove spacer material, then the etching process can be completed, but the etch selectivity is insufficient and control is poor, leading to imprecise patterning
Solution Approach 1:
The patent employs multiple etching chemistries (hydrogen-based, chlorine-based, fluorocarbon-based) with different parameters to achieve selective removal of tin oxide at different stages. By changing etching parameters such as chemistry type, temperature, and plasma power, the process achieves high selectivity for tin oxide removal while preserving other materials, thereby resolving the contradiction between patterning precision and etch selectivity
Solution Approach 2:
The etching process is divided into multiple sequential steps using different chemistries: hydrogen-based etching for initial tin oxide removal, followed by chlorine-based etching for intermediate removal, and fluorocarbon-based etching for final removal. This segmentation allows each step to target specific aspects of tin oxide removal with optimized selectivity, improving overall patterning precision while maintaining reliable etch control
2Manufacturing precision
If tin oxide is removed from horizontal surfaces to expose protruding features, then the features are exposed for further processing, but tin oxide at sidewalls must be preserved to maintain spacer integrity
Solution Approach 1:
The patent applies different etching conditions to different locations on the substrate. By controlling plasma directionality and chemistry, the process selectively removes tin oxide from horizontal surfaces while preserving tin oxide at sidewalls. This local differentiation achieves precise feature exposure without compromising spacer integrity, resolving the contradiction between exposure precision and process complexity
Solution Approach 2:
The etching process exploits the dimensional difference between horizontal surfaces and vertical sidewalls. By using anisotropic etching techniques that preferentially etch in the vertical direction while protecting horizontal surfaces, the process achieves selective tin oxide removal based on surface orientation. This dimensional approach enables precise feature exposure while maintaining spacer structure without requiring excessively complex process steps
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 enables precise patterning and formation of small-scale features with stringent critical dimension and profile requirements, meeting the demands of applications like self-aligned double and quadruple patterning, while minimizing contamination and maintaining the integrity of tin oxide spacers and hardmasks.
Implementation Method 1
etching the tin oxide using a hydrogen-based etch chemistry that results in a formation of a tin hydride
Implementation Method 2
contacting the semiconductor substrate with a plasma-activated hydrogen-containing reactant selected from the group consisting of H2, HBr, NH3, H2O, a hydrocarbon, and combinations thereof
Implementation Method 3
exposing the semiconductor substrate to a plasma-activated chlorine-containing reactant selected from the group consisting of Cl2, BCl3, and combinations thereof
Data Source
AI summary
A method of processing a substrate includes: providing a substrate having one or more mandrels comprising a mandrel material, wherein a layer of a spacer material coats horizontal surfaces and sidewalls of the one or more mandrels; and etching and completely removing the layer of the spacer material from the horizontal surfaces of the one or more mandrels and thereby exposing the mandrel material, without completely removing the spacer material residing at the sidewalls of the one or more mandrels. The etching includes exposing the substrate to a plasma formed using a mixture comprising a first gas and a polymer-forming gas, and wherein the etching comprises forming a polymer on the substrate. Polymer-forming gas may include carbon (C) and hydrogen (H).