Auxiliary Etching Layer for Residue Removal in High-Aspect-Ratio Trenches
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Solution Overview
Problem
In three-dimensional semiconductor memory structures, incomplete etching leads to stepped residues at the bottom of trenches, causing abnormal device operation and short circuits due to limited ion reach and residue formation.
Innovation Solution
An etching method and composition involving an auxiliary etching layer with a carrier and etching component, applied with energy or gas exposure to effectively remove residues, using alkali hydroxides, hydrofluoric acid, and fluorine-containing gases encapsulated in a carrier, such as active carbon or thermoplastic resin, to fill and treat the residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If anisotropic etching is used to form high-aspect-ratio openings, then storage capacity is improved, but stepped residues remain at the bottom of trenches
Solution Approach 1:
The etching process is divided into two distinct stages: a first etching process that forms the high-aspect-ratio opening with good anisotropy, and a second etching process that specifically targets and removes stepped residues at the bottom. This segmentation allows each process to be optimized for its specific function, resolving the contradiction between achieving high storage capacity and ensuring complete etching without residues.
2Manufacturing precision
If ion etching depth is increased to reach trench bottom, then etching completeness is improved, but device reliability deteriorates due to abnormal turn-on and short current
Solution Approach 1:
The invention separates the etching function into two distinct processes: the first process creates the opening structure with proper depth and anisotropy, while the second process is specifically designed to remove stepped residues without affecting the already-formed device structure. This prevents the harmful effects of excessive ion etching while ensuring complete removal of residues.
Solution Approach 2:
The patent introduces an intermediary substance (such as a sacrificial layer or specially formulated etchant) that enables selective removal of stepped residues. This intermediary allows the second etching process to target only the residues at the trench bottom without causing the abnormal turn-on and short current issues associated with direct deep ion etching.
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 and composition enable complete removal of stepped residues from high-aspect-ratio openings, ensuring proper device function and compatibility with existing semiconductor processes while being cost-effective and easily producible.
Implementation Method 1
a treatment process is performed to the auxiliary etching layer, so that the etching component etches the etching residue
Implementation Method 2
The auxiliary etching layer includes a media, a carrier disposed in the media and the etching component encapsulated by the carrier. The treatment process includes applying an energy to the auxiliary etching layer
Implementation Method 3
the gas includes ozone
Data Source
AI summary
An etching method is disclosed. A substrate is provided. An etching is performed to form at least one opening in the substrate. An auxiliary etching layer is formed in the opening to cover at least one etching residue. The auxiliary etching layer includes a media, a carrier and an etching component encapsulated by the carrier. A treatment process is performed to the auxiliary etching layer. The treatment process includes applying an energy to the auxiliary etching layer or exposing the auxiliary layer to a gas, so that the carrier breaks in the treatment and thereby the etching component is released to etch the etching residue.