Silicon Nitride Etching Composition for High Selectivity and Regrowth Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching methods for silicon nitride films face limitations in selectivity compared to silicon oxide and polycrystalline silicon, leading to inadequate suppression of polycrystalline silicon etching and oxide regrowth during semiconductor manufacturing, particularly in three-dimensional vertical NAND device production.
Innovation Solution
An etching composition comprising an inorganic acid, solvent, and additives with epoxy or vinyl groups is developed, which selectively etches silicon nitride with high selectivity over silicon oxide and polycrystalline silicon, preventing oxide regrowth by passivating the surface during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a predetermined acidic solution is used to etch silicon nitride film, then the etching process can be performed, but the etching selectivity of silicon nitride compared to polycrystalline silicon or silicon oxide film is limited
Solution Approach 1:
A silicon-based compound is introduced as an intermediary substance added to the acidic etching solution. This compound acts as a selective suppressor that preferentially protects polycrystalline silicon from etching while allowing silicon nitride to be etched, thereby enhancing etching selectivity without requiring fundamental changes to the etching chemistry
Solution Approach 2:
The composition parameters of the etching solution are modified by adding specific concentrations of silicon-based compounds (0.1-10 wt%). This parameter change transforms the etching solution from a non-selective acidic solution to a selective etching solution that differentiates between silicon nitride and polycrystalline silicon based on their different chemical reactions with the silicon-based additive
2Object-generated harmful factors
If a silicon-based compound is used as an additive to suppress etching of silicon oxide film, then etching of silicon oxide can be suppressed, but etching of polycrystalline silicon is not sufficiently suppressed and oxide regrowth occurs
Solution Approach 1:
The etching solution exhibits different local chemical effects on different materials. The silicon-based compound creates a protective effect specifically on silicon oxide surfaces through oxide layer formation, while maintaining etching capability on silicon nitride surfaces. This local differentiation in chemical interaction achieves selective protection without compromising overall etching performance
Solution Approach 2:
The silicon-based compound inadvertently causes oxide regrowth on silicon oxide surfaces, which is initially a harmful effect. However, this regrowth is converted into a beneficial protective oxide layer that prevents further etching of silicon oxide. The harmful regrowth phenomenon is thus transformed into a useful self-protection mechanism
3Productivity
If conventional etching methods are used, then etching can be performed, but adequate suppression of oxide regrowth during the etching process cannot be achieved
Solution Approach 1:
The silicon-based compound is pre-added to the etching solution before the etching process begins. This preliminary incorporation ensures that the compound is immediately available to suppress oxide regrowth as soon as etching starts, preventing oxide regrowth rather than attempting to correct it after occurrence. The protective mechanism is activated in advance throughout the etching process
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 composition achieves enhanced etching selectivity for silicon nitride, effectively suppressing oxide regrowth and enabling the manufacture of highly integrated and high-performance semiconductor devices by selectively etching silicon nitride in complex stacked structures.
Implementation Method 1
the additive includes one or both of a compound containing an epoxy group and a compound containing a vinyl group
Data Source
AI summary
Disclosed are an etching composition for selectively etching a silicon nitride, an etching method using the same, and a manufacturing method of a semiconductor device. The disclosed etching composition is an etching composition capable of increasing an etching selectivity for a silicon nitride over a silicon oxide and a polycrystalline silicon, and may include an inorganic acid, a solvent, and an additive, and the additive may include one or both of a compound containing an epoxy group and a compound containing a vinyl group. The compound containing the epoxy group may include one or more of glycid, allyl glycidyl ether, epichlorohydrin, 1,2-epoxy-3-phenoxypropane and 2,3-epoxypropyl benzene. The compound containing the vinyl group may include one or both of vinyl bromide and phenyl vinyl ether.