Boron Carbon Etch Protection Layer for High Aspect Ratio Wet Etching
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Solution Overview
Problem
Existing etch protection technologies face challenges in providing conformal coverage on three-dimensional structures with high aspect ratios and achieving desirable etch selectivity and resistance in semiconductor device processing, particularly in wet etch processes involving high concentrations of hydrofluoric acid.
Innovation Solution
A method involving the deposition of a boron and carbon-comprising wet etch protection layer, formed by heating a substrate and exposing it to a vapor phase boron precursor, which is then subjected to a wet etch process with a hydrofluoric acid solution, providing a diffusion barrier and maintaining the underlying substrate's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etch protection layers are used, then the substrate is protected during etching, but the coverage is non-conformal on high aspect ratio three-dimensional structures
Solution Approach 1:
The patent changes the chemical composition parameters of the etch protection layer by incorporating boron and carbon elements in specific ratios, and by controlling the deposition temperature (200-450°C), to achieve conformal coverage on high aspect ratio structures that conventional materials cannot provide
Solution Approach 2:
The patent uses composite materials consisting of boron and carbon elements combined in a specific structure, creating a new type of etch protection layer that provides both conformal coverage and high etch selectivity, resolving the limitation of conventional single-material approaches
2Reliability
If existing etch protection layers are used, then some protection is provided, but the etch selectivity and resistance are insufficient against high concentration hydrofluoric acid
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating boron and carbon elements with specific ratios, and controls deposition temperature (200-450°C) to create a layer with enhanced chemical resistance that provides reliable protection against high concentration HF acid etching
Solution Approach 2:
The boron and carbon comprising layer creates an inert chemical environment at the substrate surface, forming a protective barrier that prevents hydrofluoric acid from attacking the underlying substrate, thereby achieving high etch protection reliability
3Productivity
If the etch protection layer is made thinner to reduce processing time, then the etch resistance decreases
Solution Approach 1:
The patent optimizes the deposition temperature parameter (200-450°C) and boron-carbon composition ratios to achieve maximum etch resistance at minimal thickness, allowing thin layers (at least 5 nm) to provide sufficient protection while reducing processing time
Solution Approach 2:
The patent employs a thin, consumable boron-carbon protection layer that can be quickly deposited and removed, providing sufficient etch resistance during the critical etching step while minimizing overall processing time and material usage
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 boron and carbon-comprising layer demonstrates excellent conformality, reduced etch rates, and enhanced etch selectivity, effectively protecting the substrate during wet etching processes, even in high hydrogen fluoride concentrations, while maintaining the structural integrity of the underlying material.
Implementation Method 1
heating the substrate to a temperature of between about 200° C. and about 450° C.
Implementation Method 2
The heated substrate may be contacted with a vapor phase boron precursor to form a boron and carbon-comprising wet etch protection layer
Implementation Method 3
The vapor phase boron precursor may decompose on the substrate
Implementation Method 4
The boron and carbon-comprising layer may serve as a cap layer, an etch stop layer, as a layer for facilitating photolithography patterning processes, and/or as a doping layer
Implementation Method 5
wet etching a substrate with the etch protection layer in a wet etch of a hydrofluoric acid solution with a hydrogen fluoride concentration of at least about 10 wt. %
Data Source
AI summary
The disclosure relates generally to the field of processing substrates, for example comprising materials such as quartz, glass or silicon. The disclosure more particular relates to providing wet etch protection layers comprising boron and carbon and etching the substrate in a hydrogen fluoride aqueous solution. One or more of the boron and carbon containing films can have a thickness of at least 5, preferably 10 and, more preferably 30 nm. The method comprises wet etching the substrate in a hydrofluoric acid solution with a hydrogen fluoride concentration of at least 10 wt. % for at least 5 minutes.