Etching Composition for Silicon Oxide Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching methods for semiconductor devices face challenges in achieving high etch selectivity of silicon oxide layers with respect to nitride layers, as they often result in varying etch rates across different types of layers, leading to inefficiencies in miniaturization processes.
Innovation Solution
A composition comprising hydrogen fluoride, an anionic polymer, and deionized water is used, with the anionic polymer included in amounts of 0.001 to 2 wt% and hydrogen fluoride in 5 to 90 wt%, enhancing etch selectivity by reducing nitride layer etch rates while maintaining high silicon oxide layer etch rates, and optionally including ammonium fluoride and organic/inorganic acids to adjust etch rates across different silicon oxide and nitride layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching compositions (DHF or BHF) are used, then silicon oxide layer etching is achieved, but etch selectivity with respect to nitride layers deteriorates due to varying etch rates across different layer types
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by incorporating specific organic acids (acetic acid, formic acid, propionic acid) and inorganic acids (nitric acid, sulfuric acid, phosphoric acid) in controlled concentrations. This parameter adjustment enables differential etching rates where silicon oxide layers are etched efficiently while nitride layers exhibit suppressed etching, achieving the required etch selectivity without compromising overall process productivity
Solution Approach 2:
The etching composition is formulated as a composite solution containing multiple acid components (organic and inorganic acids) working synergistically. This composite approach allows the solution to exhibit selective chemical reactivity toward different semiconductor materials, enabling high etch selectivity between silicon oxide and nitride layers while maintaining stable etching performance across various layer types
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 solution achieves an etch selectivity of 80 or greater for silicon oxide layers with respect to nitride layers, allowing for efficient etching of multiple silicon oxide layers with different characteristics while minimizing nitride layer etching, thus supporting advanced semiconductor device fabrication.
Implementation Method 1
a wet etching process, which may use an etching composition including an etching active main component, e.g., a diluted hydrofluoric acid solution (DHF) or a buffer hydrofluoric acid solution (BHF)
Implementation Method 2
the etch selectivity of the silicon oxide layer with respect to a nitride layer is improved by decreasing the etch rate of various kinds of nitride layers
Data Source
AI summary
A composition for etching a silicon oxide layer, a method of etching a semiconductor device, and a composition for etching a semiconductor device including a silicon oxide layer and a nitride layer including hydrogen fluoride, an anionic polymer, and deionized water, wherein the anionic polymer is included in an amount of about 0.001 to about 2 wt % based on the total weight of the composition for etching a silicon oxide layer, and an etch selectivity of the silicon oxide layer with respect to a nitride layer is about 80 or greater.