Substrate Surface Treatment for Selective Wrap-Around Layer Etching
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Solution Overview
Problem
The deposition of amorphous silicon on the side surfaces or edges of a substrate during semiconductor manufacturing forms a wrap-around layer, which can optically or functionally damage the semiconductor device, necessitating a method to remove this layer without damaging the underlying emitter layer.
Innovation Solution
A method and system that utilize a protective liquid in a separate application zone to selectively etch the wrap-around layer using alkaline etching, while preventing the protective liquid from mixing with the alkaline solution and maintaining its presence only on the hydrophilic areas of the substrate surface to protect the emitter layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alkaline etching is performed to remove the wrap-around layer, then the wrap-around layer is removed, but the emitter layer may be damaged
Solution Approach 1:
The patent applies a protective liquid selectively to specific regions of the substrate to create local quality differences. The protective liquid is applied to the emitter layer region while excluding the wrap-around layer region, allowing alkaline etching to remove the wrap-around layer without damaging the emitter layer. This spatial differentiation of protection enables selective etching with high precision and safety.
Solution Approach 2:
The protective liquid acts as an intermediary substance between the alkaline etching solution and the emitter layer. It forms a protective barrier that prevents direct contact between the harsh alkaline solution and the sensitive emitter layer, thereby mediating the interaction to achieve safe removal of the wrap-around layer while preserving the emitter layer integrity.
2Reliability
If protective liquid is applied in the same zone as alkali bath, then protection is provided, but protective liquid mixes with alkaline solution reducing effectiveness
Solution Approach 1:
The patent divides the treatment zone into distinct segments: a protective liquid application zone and an alkali bath zone. This segmentation prevents mixing between the protective liquid and alkaline solution by spatial separation. The substrate sequentially passes through these segmented zones, allowing independent control of each chemical environment and maintaining the effectiveness of both solutions.
3Productivity
If alkali bath is expanded for high-temperature etching, then etching efficiency increases, but components are pushed due to thermal expansion
Solution Approach 1:
The patent extracts the harmful thermal expansion effect by separating the protective liquid application zone from the high-temperature alkali bath zone. By applying the protective liquid before the substrate enters the hot alkali bath, the system eliminates the problematic interaction between thermal expansion and protective liquid displacement, while still maintaining high etching efficiency in the dedicated alkali bath zone.
4Productivity
If oxide film is not removed before alkaline etching, then process steps are reduced, but etching reaction rate is delayed
Solution Approach 1:
The patent performs preliminary removal of the oxide film from the substrate surface before the alkaline etching process. This preliminary action clears the surface to enable the subsequent alkaline etching to proceed at maximum reaction rate without the oxide film acting as a barrier. The sequence of operations ensures optimal etching efficiency while maintaining a reasonable process flow.
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
Effectively removes the wrap-around layer without damaging the emitter layer, while preventing mixing of the protective liquid with alkaline solutions and avoiding space occupation issues during high-temperature etching processes.
Implementation Method 1
removing an oxide film on the side surfaces or bottom surface of a substrate by using an acidic solution, contained in an acid bath, in the acid bath
Implementation Method 2
removing a wrap-around layer on the side surfaces or edges of the top surface of the substrate coated with the protective liquid by using an alkaline solution, contained in an alkali bath, in the alkali bath
Implementation Method 3
removing a wrap-around layer on the side surfaces or edges of the top surface of the substrate coated with the protective liquid by using an alkaline solution, contained in an alkali bath, in the alkali bath
Data Source
AI summary
Disclosed herein are a method and system for treating surfaces of a substrate. According to an embodiment, there is provided a method for treating surfaces of a substrate, the method including: removing an oxide film on the side surfaces or bottom surface of a substrate by using an acidic solution, contained in an acid bath, in the acid bath; applying a protective liquid to the top surface of the substrate, from which the oxide film has been removed, in a protective liquid application zone; and removing a wrap-around layer on the side surfaces or edges of the top surface of the substrate coated with the protective liquid by using an alkaline solution, contained in an alkali bath, in the alkali bath.