Substrate Treating Apparatus Pattern Roughness Control
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Solution Overview
Problem
The etch back process for manufacturing CMOS image sensors is hindered by pattern roughness, which affects pixel light interference and image sensor refinement, necessitating an improvement in substrate treatment techniques during the etching process.
Innovation Solution
A substrate treating apparatus and method that involves injecting a first process gas and a second process gas with different components, where the second process gas includes a fluorine component and a hydrogen component, injected in larger amounts, to improve pattern roughness by using CF4 as the first process gas and CHF3 as the second process gas, either mixed or supplied separately, to enhance etching and deposition treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etch back process is performed using a single process gas, then the etching process can be completed, but pattern roughness increases affecting pixel light interference and image sensor refinement
Solution Approach 1:
The patent divides the etching process into multiple stages by sequentially using different process gases (CF4, CHF3, SF6) with distinct chemical properties. Each gas performs a specific function: CF4 for initial etching, CHF3 for smoothing, and SF6 for final etching, thereby segmenting the overall process to achieve both etching completion and pattern roughness reduction
Solution Approach 2:
The patent changes the chemical composition parameters of the process gas throughout the etching sequence. By transitioning from CF4 to CHF3 and then to SF6, the chemical reactivity and etching characteristics are dynamically adjusted to first remove material, then smooth the surface, and finally complete the etching, thereby controlling pattern roughness while maintaining etching effectiveness
2Manufacturing precision
If the second process gas (CHF3) is injected in larger amounts than the first process gas (CF4), then pattern roughness is significantly improved, but the process complexity increases
Solution Approach 1:
The patent maintains continuous process gas flow throughout the etching sequence without interrupting the vacuum environment. The transition from CF4 to CHF3 and then to SF6 is performed continuously, ensuring that the useful action of surface treatment continues uninterrupted while systematically improving pattern roughness through each gas stage
Solution Approach 2:
The patent employs periodic switching between different process gases in a predetermined sequence. Each gas is introduced for a specific duration to perform its designated function, creating a periodic cycle of etching, smoothing, and finishing operations that systematically reduces pattern roughness while managing process complexity through structured timing
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 approach significantly improves pattern roughness, resulting in a smoother surface texture of the CMOS image sensor substrates, effectively addressing the interference and refinement challenges associated with conventional etch back processes.
Implementation Method 1
a plasma generation unit including a first electrode disposed in an upper part of the housing, a second electrode disposed to face the first electrode and included in the substrate support unit, a first high frequency power supply configured to supply RF power to the first electrode, and a second high frequency power supply configured to supply the RF power to the second electrode
Data Source
AI summary
Provided are a substrate treating apparatus and a method thereof that can improve pattern roughness when an etching process is performed for a substrate. The substrate treating method comprises: inserting a substrate into a substrate treating apparatus; injecting a first process gas into the substrate treating apparatus and treating the substrate to a first plasma using the first process gas; and injecting a second process gas into the substrate treating apparatus and treating the substrate to a second plasma using the second process gas, wherein at least some components of the second process gas differ from those of the first process gas.