Wafer Thermal Processing for Defect Control
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Solution Overview
Problem
The fabrication of semiconductor devices is hindered by defects such as point defects, metal impurities, and hot carrier effects, which affect the performance and reliability of the devices, and existing solutions like hydrogen passivation and oxygen precipitation face challenges in optimizing process parameters and avoiding damage to active regions.
Innovation Solution
A thermal processing method involving rapid heating and cooling cycles in non-oxygenated and oxygenated gas mixtures is used to reduce defects, form a denuded zone, and generate bulk micro-defects away from active regions, while incorporating deuterium atoms to bind with dangling bonds and enhance device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen passivation treatment is performed to bind dangling bonds and reduce defects, then device performance is improved, but dopants may react with hydrogen at high temperature causing process optimization difficulties
Solution Approach 1:
The patent employs rapid thermal processing with precisely controlled temperature-time parameters to achieve passivation treatment while minimizing dopant-hydrogen reactions. The rapid heating and cooling rates allow the process to proceed through specific thermal profiles that optimize passivation effectiveness while avoiding conditions that cause harmful reactions.
Solution Approach 2:
The patent utilizes cyclic rapid thermal processing with alternating heating and cooling phases. This periodic thermal action allows controlled introduction of hydrogen for passivation during heating phases while rapid cooling phases prevent excessive dopant-hydrogen reactions, thereby optimizing both passivation effectiveness and process controllability.
2Reliability
If oxygen precipitations are generated to trap metal impurities and strengthen wafer, then intrinsic gettering is improved, but gate oxide integrity may be ruined causing leakage current in active regions
Solution Approach 1:
The patent applies rapid thermal processing to create localized thermal gradients that promote oxygen precipitation specifically in bulk regions away from active device areas. The rapid heating and cooling cycles enable controlled nucleation and growth of oxygen precipitates in targeted zones, achieving intrinsic gettering without compromising gate oxide integrity in active regions.
Solution Approach 2:
The patent segments the wafer into different thermal zones during rapid thermal processing, with the bulk region experiencing conditions favorable for oxygen precipitation while active regions are protected. This spatial segmentation allows simultaneous achievement of intrinsic gettering in bulk and preservation of device quality in active areas.
3Manufacturing precision
If rapid heating and cooling cycles are performed to form denuded zone and reduce defects, then grown-in defects are reduced, but process control complexity increases
Solution Approach 1:
The patent implements periodic rapid thermal cycles with standardized heating and cooling phases. These repeating cycles create consistent thermal profiles that reliably produce denuded zones and reduce grown-in defects. The periodic nature of the process, while requiring precise control, establishes a repeatable methodology that manages complexity through standardization.
Solution Approach 2:
The patent utilizes specific parameter ranges for rapid thermal processing including controlled heating rates, peak temperatures, and cooling rates. By optimizing these parameters within defined ranges, the process achieves reliable denuded zone formation and defect reduction while maintaining manageable process control through established parameter windows.
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 method reduces point defects, improves interface characteristics, suppresses dislocation slipping, and increases the reliability and performance of semiconductor devices by forming a denuded zone and controlling bulk micro-defects, thereby enhancing resistance to hot carriers and reducing leakage current.
Implementation Method 1
performing a rapid heating process on a surface of the least one wafer to heat the least one wafer to a predetermined high temperature
Implementation Method 2
performing a rapid cooling process on a surface of the least one wafer
Implementation Method 3
The deuterium atoms are bound with Group III, IV or V elements in covalent bonds to form a stable structure
Implementation Method 4
generate oxygen precipitations in the wafers from residual interstitial oxygen atoms in a heating process
Data Source
AI summary
The present invention relates to a thermal processing method for wafer. A wafer is placed in an environment filled with a non-oxygenated gas mixture comprising deuterium gas and at least one kind of low active gas, and a rapid heating processing process is performed on a surface of the wafer to heat the wafer to a predetermined high temperature. Then, the wafer is placed in an environment filled with an oxygenated gas mixture, and a rapid cooling processing process is performed on a surface of the wafer. As a result, a denuded zone is formed on the surface of the wafer, deuterium atoms, which may be released to improve characteristics at an interface of semiconductor devices in a later fabrication process, are held in the wafer, and bulk micro-defects are formed far from the semiconductor devices.