Low-Temperature ALD Passivation Film for Uniform Trench Etching
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Solution Overview
Problem
Conventional sacrificial passivation film deposition methods face challenges in maintaining uniform trench etching dimensions and high aspect ratio trench structures due to limitations in low-temperature processing, leading to bowing and tapering phenomena, and require additional high-temperature processes for film removal, increasing costs and reducing productivity.
Innovation Solution
A low-temperature atomic layer deposition (ALD) process is employed, combining thermal ALD for primary film deposition and plasma ALD for secondary film deposition on upper and side surfaces, using a silylamine compound as a silicon precursor to enable isotropic deposition at temperatures below 150°C, allowing for easy removal of the sacrificial passivation film during etching without additional processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma ALD is used to deposit sacrificial passivation film, then film deposition on upper surface and side surface is improved, but temperature requirement increases to 200-400°C
Solution Approach 1:
The patent changes the temperature parameter from conventional 200-400°C to below 150°C by selecting specific reactants (silylamine compound and water) and optimizing the thermal ALD process conditions, achieving both low-temperature deposition and sufficient film quality for sacrificial passivation
Solution Approach 2:
The patent uses thermal ALD as an alternative copy of plasma ALD, achieving similar film deposition results through a different mechanism (thermal reaction instead of plasma activation), thereby avoiding the high temperature requirement while maintaining manufacturing precision
2Temperature
If conventional thermal ALD is used at low temperature, then processing temperature is reduced, but film deposition quality and coverage are insufficient
Solution Approach 1:
The patent optimizes multiple parameters including temperature (below 150°C), reactant selection (silylamine compound and water), and process timing to achieve sufficient film deposition quality at low temperature, resolving the trade-off between temperature reduction and film quality
Solution Approach 2:
The patent employs a two-layer composite sacrificial passivation film structure with a first layer (3-10 nm) and a second layer (1-3 nm), where each layer serves different functions: the first layer provides base coverage and the second layer enhances protection, together achieving superior deposition quality at low temperature
3Productivity
If high-temperature process is used for film removal, then film removal efficiency is improved, but additional process steps and costs increase
Solution Approach 1:
The patent designs the sacrificial passivation film with specific low-temperature deposition characteristics that inherently enable easy removal during subsequent etching processes, converting the low-temperature deposition advantage into a benefit for simplified removal without requiring additional high-temperature steps
Solution Approach 2:
The sacrificial passivation film is designed to be automatically removed during the subsequent etching process through its inherent chemical properties, eliminating the need for separate removal steps and reducing overall process complexity
4Manufacturing precision
If separate devices are used for low-temperature deposition and etching, then processing quality is maintained, but productivity decreases
Solution Approach 1:
The patent merges the low-temperature thermal ALD deposition process with the subsequent etching process into a single integrated device, eliminating the need for separate devices and intermediate handling steps, thereby improving productivity while maintaining processing quality through careful process sequencing
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 ensures uniform trench etching, reduces film loss, and eliminates the need for separate high-temperature annealing, enhancing productivity and cost-effectiveness by enabling one-chamber processing and easy removal of the sacrificial passivation film during etching.
Implementation Method 1
using a silylamine compound as a silicon precursor to enable isotropic deposition at temperatures below 150°C
Implementation Method 2
additionally depositing a secondary sacrificial passivation film on an upper surface and a side surface of an upper portion of the primary sacrificial passivation film using a plasma-ALD (P-ALD) process
Data Source
AI summary
A sacrificial passivation film deposition method according to an exemplary embodiment of the present disclosure may include: depositing a primary sacrificial passivation film on an entire surface of a substrate using a thermal ALD (T-ALD) process; and additionally depositing a secondary sacrificial passivation film on an upper surface and at least a portion of a side surface of an upper portion of the primary sacrificial passivation film using a plasma-ALD (P-ALD) process.