Silicon Wafer Heat Treatment Void Defect Annihilation
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Solution Overview
Problem
Current methods for heat treating silicon single crystal wafers are costly and inefficient in annihilating void defects and micro oxide precipitate nuclei, particularly as they often require two-step processes and cannot fully eliminate defects throughout the wafer thickness, leading to issues with electrical properties and contamination.
Innovation Solution
A method involving a heat treatment in an oxidizing ambient, where the temperature, oxygen concentration, and void size are correlated to effectively annihilate void defects and micro oxide precipitate nuclei, using the formula T≥37.5[Oi]+1.74Lvoid+890, with a heat treatment temperature between 900°C and 1200°C, and an oxygen concentration of 8 ppma-JEIDA or less, to ensure efficient and cost-effective defect removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-step heat treatment process is used to annihilate void defects, then defect removal effectiveness is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the non-oxidizing heat treatment step and oxidizing heat treatment step into a single integrated heat treatment process. The furnace atmosphere is switched from non-oxidizing to oxidizing during the heating process, eliminating the need for separate treatment steps while achieving the same defect annihilation效果. This reduces process complexity and manufacturing cost while maintaining high defect removal effectiveness.
2Reliability
If heat treatment temperature is increased to annihilate void defects, then defect removal effectiveness is improved, but slip dislocation generation increases
Solution Approach 1:
The patent optimizes the heat treatment temperature parameter to a specific range (900-1200°C) that balances two competing requirements: high enough to annihilate void defects effectively, but low enough to suppress slip dislocation generation. Additionally, the patent changes the oxygen concentration parameter by switching from non-oxidizing to oxidizing atmosphere during treatment, which modifies the defect annihilation mechanism to achieve better results at lower temperatures, thereby reducing slip dislocation generation.
3Reliability
If oxygen concentration is increased during heat treatment, then void defect annihilation is improved, but oxide precipitate formation increases
Solution Approach 1:
The patent performs non-oxidizing heat treatment first to dissolve the oxide films on the inner walls of void defects, preparing the voids for subsequent annihilation. Only after this preliminary preparation step does the patent switch to oxidizing atmosphere to annihilate the voids. This sequential approach ensures that oxygen is introduced only when needed, minimizing unnecessary oxide precipitate formation while achieving effective void defect annihilation.
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 securely annihilates void defects and suppresses slip dislocation generation, achieving a defect-free silicon single crystal wafer suitable for semiconductor devices, while reducing costs and maintaining wafer integrity.
Implementation Method 1
performing the heat treatment based on a condition determined by a tripartite correlation between a heat treatment temperature during the heat treatment, an oxygen concentration in the silicon single crystal wafer before the heat treatment, and a void size in the silicon single crystal wafer before the heat treatment
Data Source
AI summary
The present invention is a method for a heat treatment of a silicon single crystal wafer in an oxidizing ambient, including: performing the heat treatment based on a condition determined by a tripartite correlation between a heat treatment temperature during the heat treatment, an oxygen concentration in the silicon single crystal wafer before the heat treatment, and a void size in the silicon single crystal wafer before the heat treatment. This provides a method for a heat treatment of a silicon single crystal wafer which can annihilate void defects or micro oxide precipitate nuclei in a silicon single crystal wafer with low cost, efficiently, and securely by a heat treatment in an oxidizing ambient.