Two-Step Self-Aligned Source Etch Polymer Sidewall Protection
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Solution Overview
Problem
Conventional self-aligned source (SAS) etching processes often result in undesirable loss of material at the corners and sidewalls of semiconductor structures, leading to poor profiles and reduced performance in integrated circuits, especially when trying to fabricate devices with critical dimensions less than 135 nanometers.
Innovation Solution
A two-step SAS etching process that forms protective polymer layers on the sidewalls of non-target structures, allowing for precise etching without significant material loss, maintaining structure definition and extending the etching process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional self-aligned source etching process is used, then etching can be performed on semiconductor structures, but material loss occurs at corners and sidewalls resulting in poor profiles
Solution Approach 1:
A protective polymer layer is deposited on the sidewalls of gate structures before the etching process begins. This preliminary protective layer prevents material loss at corners and sidewalls during etching, ensuring well-defined profiles without the harmful effects of conventional SAS etching
Solution Approach 2:
The patent introduces a polymer layer as an intermediary substance between the etching plasma and the gate structure sidewalls. This polymer layer acts as a protective barrier that mediates the interaction, preventing direct etching damage to the sidewalls while allowing the etching process to proceed on the oxide layer
2Quantity of substance
If etching depth is increased to achieve desired pattern transfer, then more material is removed, but material loss at sidewalls increases leading to poor structure definition
Solution Approach 1:
The protective polymer layer is applied before etching to prevent sidewall damage during the entire etching process, allowing deep etching to be performed while maintaining structure definition
Solution Approach 2:
The polymer layer serves as a protective intermediary that enables deep etching without compromising sidewall integrity, allowing complete pattern transfer while preserving structure definition
3Measurement precision
If conventional SAS etching is used for smaller devices, then lithography resolution is improved, but material loss and profile degradation occur
Solution Approach 1:
The protective polymer layer is deposited before etching to prevent material loss, enabling the use of SAS etching for high-resolution lithography without suffering from the material loss and profile degradation problems of conventional processes
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 ensures well-defined profiles and reduced material loss, enhancing the performance and complexity of integrated circuits by maintaining the integrity of gate structures during the etching process, particularly beneficial for manufacturing flash devices and other small-dimensional semiconductor devices.
Implementation Method 1
performing a first dry etching process at a first depth causes forming a first polymer layer overlying the first sidewall and a second polymer layer overlying the second sidewall
Implementation Method 2
performing a first dry etching process at a first depth, which causes forming a first polymer layer overlying the first sidewall and a second polymer layer overlying the second sidewall. In addition, the first dry etching process removes at least a second thickness of the second portion
Data Source
AI summary
System and method for self-aligned etching. According to an embodiment, the present invention provides a method for performing self-aligned source etching process. The method includes a step for providing a substrate material. The method also includes a step for forming a layer of etchable oxide material overlying at least a portion of the substrate material. The layer of etchable oxide material can characterized by a first thickness. The layer of etchable oxide material includes a first portion, a second portion, and a third portion. The second portion is positioned between the first portion and the third portion. The method additionally includes a step for forming a plurality of structures overlying the layer of etchable oxide material. The plurality of structures includes a first structure and a second structure.