Semiconductor Trench Corner Rounding via Inert Gas Heat Treatment
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Solution Overview
Problem
Existing heat treatment methods for semiconductor substrates using silicon carbide (SiC) substrates face challenges with sharp trench corners causing coating defects and electrical breakdown, and require flammable and explosive gases, leading to decreased productivity and increased costs.
Innovation Solution
A heat treatment method and apparatus that seals inert gases, such as argon, at pressures exceeding the molecular flow region to round trench corners without using flammable or explosive gases, improving productivity and eliminating the need for expensive safety equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed in Ar gas atmosphere or SiH4 gas/inert gas atmosphere at 1600°C to 1800°C followed by heat treatment in hydrogen atmosphere at 1400°C to 1500°C, then the sharp corners at the trench are rounded to ease electric field concentration, but productivity decreases significantly and expensive safety equipment is required
Solution Approach 1:
The invention changes the parameters of heat treatment by performing it in an inert gas atmosphere (Ar, N2, or Kr) at atmospheric pressure or slightly above, at a temperature of 1500°C to 2000°C for 1 to 30 minutes. This single-step process replaces the conventional two-step process using SiH4 and H2 gases at lower temperatures, achieving the same rounding effect while improving productivity and eliminating safety equipment requirements
Solution Approach 2:
The invention uses inert gases (Ar, N2, or Kr) as the treatment atmosphere instead of flammable SiH4 and explosive H2 gases. This eliminates the need for dedicated gas introduction lines, gas detectors, and waste gas treatment apparatus, significantly reducing equipment costs and improving productivity while maintaining the ability to round trench corners effectively
2Reliability
If heat treatment is performed in Ar gas atmosphere or SiH4 gas/inert gas atmosphere at 1600°C to 1800°C followed by heat treatment in hydrogen atmosphere at 1400°C to 1500°C, then the sharp corners at the trench are rounded to ease electric field concentration, but the cost increases significantly due to auxiliary safety equipment
Solution Approach 1:
The invention uses inert gases (Ar, N2, or Kr) as the treatment atmosphere instead of flammable SiH4 and explosive H2 gases. This eliminates the need for dedicated gas introduction lines, gas detectors, and waste gas treatment apparatus, significantly reducing equipment costs and improving productivity while maintaining the ability to round trench corners effectively
Solution Approach 2:
The invention replaces expensive safety equipment and complex gas handling systems with a simple inert gas atmosphere process. The use of atmospheric pressure or slightly above eliminates the need for complex vacuum or pressure control systems, making the process cheaper and easier to implement while achieving the same reliability improvement
3Shape
If heat treatment is performed at high temperature to round trench corners, then the shape of the trench is improved, but the trench width may change and productivity decreases
Solution Approach 1:
The invention optimizes the parameters of heat treatment by performing it in an inert gas atmosphere (Ar, N2, or Kr) at atmospheric pressure or slightly above, at a temperature of 1500°C to 2000°C for 1 to 30 minutes. This single-step process replaces the conventional two-step process, achieving the same rounding effect while improving productivity and eliminating safety equipment requirements
Solution Approach 2:
The invention performs the rounding action in a single heat treatment step before subsequent processing steps. By completing the shape modification early in the process flow using the optimized inert gas atmosphere method, subsequent steps can proceed without delay, improving overall productivity while maintaining precise control over trench shape
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 method effectively rounds trench corners while maintaining high productivity and avoiding the use of hazardous gases, thus enhancing semiconductor device reliability and reducing costs.
Implementation Method 1
heating means provided in the treatment chamber
Data Source
AI summary
A heat treatment method for a semiconductor substrate is provided which improves the shapes of the sharp corners at the opening and the bottom of a trench without using flammable or explosive gas while improving productivity. The heat treatment is performed on a semiconductor substrate with a recess formed therein in a treatment chamber where gas is sealed at a pressure exceeding a pressure in a molecular flow region.