Sacrificial Oxide Film Formation for Nitride Removal
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Solution Overview
Problem
Existing methods for removing undesirable nitride regions in semiconductor manufacturing, such as those formed during field oxidation or STI film processes, often result in stress-induced junction leakage due to the diffusion of oxidizing species into the trench, leading to increased leakage current.
Innovation Solution
A method involving the formation of a sacrificial oxide film under a hydrogen and oxygen atmosphere at elevated temperatures, which allows for the efficient removal of nitride regions without further oxidizing the trench surfaces, thereby preventing stress and leakage current issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry or wet oxidation is used to remove nitride regions, then the nitride regions are removed, but the oxidizing species diffuse into the STI film and oxidize the silicon substrate in the trench, causing the STI film to expand and increase junction leakage current
Solution Approach 1:
The patent uses a hydrogen atmosphere during the oxidation process to prevent oxidizing species from diffusing into the STI film. The hydrogen atmosphere creates an inert environment that protects the trench region from unwanted oxidation, thereby preventing STI film expansion and reducing junction leakage current while still allowing nitride regions to be removed.
Solution Approach 2:
The patent changes the atmospheric composition parameter from conventional dry or wet oxidation (using oxygen or steam) to a hydrogen atmosphere. This parameter change fundamentally alters the chemical environment, preventing oxidizing species diffusion into the STI film while maintaining the ability to remove nitride regions through controlled oxidation.
2Ease of manufacture
If ozone atmosphere is used to form the sacrificial oxide film, then the oxide film is formed, but the temperature must be kept below 800°C due to poor thermal-resistivity of ozone, increasing processing time
Solution Approach 1:
The patent changes the atmospheric composition from ozone to a hydrogen and oxygen mixture. This parameter change allows the processing temperature to be increased above 800°C, significantly reducing the time required to form the sacrificial oxide film while maintaining ease of manufacture through controlled oxidation.
Solution Approach 2:
The patent uses a hydrogen and oxygen atmosphere that provides strong oxidizing conditions, enabling faster oxide formation kinetics. This allows the sacrificial oxide film to be formed more rapidly at elevated temperatures, reducing processing time compared to using ozone which has poor thermal-resistivity.
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 significantly reduces the time required for sacrificial oxide film formation and prevents the expansion of the STI film, resulting in lower junction leakage currents compared to conventional methods.
Implementation Method 1
Under an atmosphere comprising hydrogen and oxygen, a sacrificial oxide film is formed on a silicon substrate that is provided with at least one nitride region
Data Source
AI summary
Provided is a method of manufacturing a semiconductor device including at least two processes. Under an atmosphere comprising hydrogen and oxygen, a sacrificial oxide film is formed on a silicon substrate that is provided with at least one nitride region. Then, the sacrificial oxide film and the nitride region are removed from the silicon substrate.