Void-Free SiO2 Filling in Recessed Features
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Solution Overview
Problem
Void-less and seamfree filling of fine recessed features with silicon dioxide (SiO2) material at low temperatures is challenging, and existing methods lack effective selective deposition of SiO2 films on different materials.
Innovation Solution
A method involving a substrate with recessed features coated with a metal-containing catalyst layer, exposed to a silanol gas at a temperature of 150° C. or less in the absence of oxidizing and hydrolyzing agents, allowing for conformal SiO2 film deposition without voids or seams, suitable for forming shallow trench isolation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional high-temperature SiO2 deposition methods are used, then good filling quality is achieved, but substrate temperature must be high which limits process integration
Solution Approach 1:
The patent changes the deposition parameters by using silane-based precursors with controlled hydrolysis and oxidation conditions at low temperatures (below 400°C), replacing conventional high-temperature CVD processes. This allows achieving void-free filling quality while maintaining low substrate temperature through precise control of reaction kinetics and precursor delivery parameters.
Solution Approach 2:
The patent employs a composite deposition approach combining silane precursor deposition with controlled hydrolysis and oxidation steps, creating a multi-stage process that achieves both low temperature operation and high filling quality. The composite nature of the process integrates multiple chemical reactions to overcome the limitations of single-step conventional methods.
2Temperature
If low-temperature SiO2 deposition is attempted, then substrate temperature is reduced, but void formation and seam defects occur
Solution Approach 1:
The patent ensures continuous and uniform deposition by optimizing precursor delivery and reaction conditions throughout the low-temperature process. The continuous supply of silane precursors and controlled hydrolysis/oxidation reactions maintain steady film growth without interruption, preventing void formation and ensuring seamless filling even at low substrate temperatures.
Solution Approach 2:
The patent implements process monitoring and control mechanisms to detect and correct deposition anomalies in real-time. By monitoring deposition rate, film uniformity, and reaction conditions, the system can adjust precursor flow rates and temperature profiles dynamically to prevent void formation and maintain high filling quality throughout the low-temperature deposition process.
3Adaptability or versatility
If selective SiO2 deposition on different materials is required, then process complexity increases, but conventional methods lack selectivity
Solution Approach 1:
The patent introduces surface preparation steps and intermediary layers that modify substrate surfaces to enable selective SiO2 deposition. By using catalyst layers or surface treatments as intermediaries, the process achieves material-selective deposition without requiring complex equipment modifications, balancing selectivity with process simplicity.
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
Enables void-free and seamless filling of fine recessed features and selective SiO2 deposition on various materials, matching the properties of conventional high-temperature SiO2, suitable for low-temperature processing and integration in semiconductor devices.
Implementation Method 1
coating surfaces of the recessed features with a metal-containing catalyst layer, and in the absence of any oxidizing and hydrolyzing agent, exposing the substrate at a substrate temperature of approximately 150° C. or less, to a process gas containing a silanol gas to deposit a conformal SiO2 film
Data Source
AI summary
Methods for void-free SiO2 filling of fine recessed features and selective SiO2 deposition on catalytic surfaces are described. According to one embodiment, the method includes providing a substrate containing recessed features, coating surfaces of the recessed features with a metal-containing catalyst layer, in the absence of any oxidizing and hydrolyzing agent, exposing the substrate at a substrate temperature of approximately 150° C. or less, to a process gas containing a silanol gas to deposit a conformal SiO2 film in the recessed features, and repeating the coating and exposing at least once to increase the thickness of the conformal SiO2 film until the recessed features are filled with SiO2 material that is void-free and seamless in the recessed features. In one example, the recessed features filled with SiO2 material form shallow trench isolation (STI) structures in a semiconductor device.