Insulating Film Formation via Silane Underlayer and Polysilazane Coating
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Solution Overview
Problem
Conventional methods for forming insulating films in electronic devices, such as trench isolation structures and inter-metal dielectric films, face challenges in achieving high precision and density, particularly in deep trenches, leading to insufficient oxidation and issues like cracks and crystal defects due to volume shrinkage during hardening.
Innovation Solution
A method involving coating a substrate with a silicon dioxide dispersion containing fine particles, a polymer, and a surfactant, followed by a polysilazane composition, and then heating to convert polysilazane into silicon dioxide, ensuring homogeneous and high-density film formation with reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polysilazane composition is applied to fill deep trenches with high aspect ratios, then trench isolation structure can be formed, but insufficient oxidation occurs at the bottom of trenches due to inadequate oxygen and moisture supply
Solution Approach 1:
The patent applies a silane-based composition as a preliminary layer before applying polysilazane. This preliminary silane layer oxidizes more readily and completely than polysilazane alone, especially in deep trenches where oxygen and moisture supply is limited. The silane layer serves as an oxidation-promoting underlayer that ensures complete conversion to silicon dioxide even at the bottom of high aspect ratio trenches.
Solution Approach 2:
The patent modifies the chemical composition parameters by using a silane-based composition (such as tetraethyl orthosilicate or trimethylsilyl nitrate) instead of conventional polysilazane alone. This compositional change alters the oxidation characteristics, enabling more complete and uniform oxidation throughout the trench depth, particularly at the bottom regions where oxygen diffusion is most limited.
2Reliability
If polysilazane-containing composition is hardened to form insulating films, then inter-metal dielectric or pre-metal dielectric films can be formed, but large volume shrinkage occurs during hardening causing cracks and crystal defects
Solution Approach 1:
The patent creates a composite structure by forming an insulating film from a silane-based composition that converts to silicon dioxide. This composite approach, using silane derivatives with different shrinkage characteristics compared to polysilazane, reduces the overall volume shrinkage during hardening and prevents the formation of cracks and crystal defects at interfaces.
Solution Approach 2:
The patent changes the chemical composition from polysilazane to silane-based compounds (such as tetraethyl orthosilicate, trimethylsilyl nitrate, or their mixtures). This compositional parameter change fundamentally alters the hardening and volume change characteristics, resulting in more stable volume during the conversion process and eliminating the crack and defect formation issues associated with polysilazane.
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
This approach enables the formation of insulating films with high bulk density and improved etching durability, even in trenches with high aspect ratios, while reducing cracks and crystal defects at the interface.
Implementation Method 1
a step of coating with silicon dioxide fine particles, in which a substrate is coated with a silicon dioxide dispersion containing silicon dioxide fine particles
Implementation Method 2
a step of heating, in which the substrate coated with the polysilazane composition is heated, so as to covert the polysilazane into silicon dioxide
Implementation Method 3
heated, so as to covert the polysilazane into silicon dioxide
Data Source
AI summary
[Problem] To provide a method capable of forming an insulating film having homogeneous and high bulk density and less suffering defects. [Means for solving] A substrate surface is coated with a silicon dioxide dispersion containing silicon dioxide fine particles, a polymer, a surfactant and a dispersion medium; and then further coated with a polysilazane composition; and thereafter heated to form an insulating film.