Silicon Wafer Heat Treatment for BMD Density Control
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Solution Overview
Problem
Existing methods for heat-treating silicon single crystal wafers fail to control bulk defect-free BMD density effectively, leading to inconsistent wafer quality.
Innovation Solution
A method involving RTA heat treatment in a nitriding atmosphere followed by a second heat treatment to form a relational equation between BMD density and RTA temperature, allowing for precise control of BMD density through optimized temperature and time conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heat treatment methods are used to control BMD distribution in thickness direction, then BMD distribution can be controlled, but BMD density cannot be controlled
Solution Approach 1:
The invention changes the RTA temperature parameter to control BMD density. By establishing a relational equation between RTA temperature and BMD density, the method enables precise control of BMD density through temperature adjustment during the RTA process, transforming an uncontrolled parameter into a controllable one.
Solution Approach 2:
The invention implements feedback control by using the established relational equation to predict BMD density based on RTA temperature. This allows for real-time adjustment and control of BMD density, ensuring consistent wafer quality through a closed-loop control mechanism where the relationship between temperature and density is continuously utilized.
2Productivity
If RTA temperature is increased to implant vacancies efficiently, then vacancy implantation improves, but manufacturing precision of BMD density deteriorates without relational equation
Solution Approach 1:
The invention performs preliminary action by establishing the relational equation between RTA temperature and BMD density before actual production. This pre-established relationship allows for accurate prediction and control of BMD density, enabling manufacturers to set appropriate RTA temperatures in advance to achieve desired BMD density values.
Solution Approach 2:
The invention replaces trial-and-error experimental methods with a mathematical relational equation. Instead of mechanically adjusting temperatures through repeated experiments, the patent substitutes this with a theoretical model that directly predicts BMD density from RTA temperature, enabling precise control without extensive experimentation.
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 the manufacturing of annealed or epitaxial wafers with defect-free surfaces and predetermined BMD density, ensuring precise control over wafer quality.
Implementation Method 1
performing an RTA treatment on a defect-free wafer in a nitriding atmosphere to implant vacancies into the wafer
Implementation Method 2
performing a precipitation treatment by heat-treating the silicon wafer to form a defect-free layer in the surface layer while precipitating oxygen in vacancies inside the wafer
Implementation Method 3
performing a heat treatment to form a DZ layer in the surface thereof
Data Source
AI summary
A method for heat-treating a silicon single crystal wafer to control a BMD density thereof to achieve a predetermined BMD density by performing an RTA heat treatment on a silicon single crystal wafer composed of an Nv region in a nitriding atmosphere, and then performing a second heat treatment, the method including: formulating a relational equation for a relation between BMD density and RTA temperature in advance; and determining an RTA temperature for achieving the predetermined BMD density according to the relational equation. Consequently, a method for heat-treating a silicon single crystal wafer for manufacturing an annealed wafer or an epitaxial wafer each having defect-free surface and a predetermined BMD density in a bulk portion thereof.