SOI Wafer Splitting via Rapid Thermal Processing and Microwaves
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Solution Overview
Problem
Existing methods for preparing SOI wafers, such as SIMOX and Smart Cut, face challenges in defect elimination and uniformity, while thermal microwave wafer-splitting methods result in non-uniform film thickness and high surface roughness.
Innovation Solution
A method utilizing rapid thermal processing (RTP) and microwaves to split bonded silicon wafers, involving oxidation, hydrogen implantation, and bonding, with controlled temperature and microwave power to achieve uniform energy distribution and efficient wafer splitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal microwave wafer-splitting is used to split bonded wafers, then wafer splitting can be achieved, but the film thickness becomes non-uniform and surface roughness increases
Solution Approach 1:
The patent changes the heating method from conventional thermal microwave to rapid thermal processing (RTP), adjusting temperature parameters (heating rate, peak temperature, holding time) to achieve uniform wafer splitting while maintaining film thickness uniformity and low surface roughness
Solution Approach 2:
The patent replaces the thermal microwave heating system with a rapid thermal processing system that uses halogen lamps or other rapid heating sources, substituting the heating mechanism to eliminate the non-uniform heating problem while maintaining the wafer splitting function
2Device complexity
If conventional thermal processing is used for wafer splitting, then the process is simple, but the splitting speed is slow and productivity is low
Solution Approach 1:
The patent changes the temperature profile parameters by implementing rapid heating rates (10-200°C/second) and optimized holding times (30 seconds to 10 minutes), which dramatically increases the splitting speed while maintaining process control and simplicity
Solution Approach 2:
The patent uses periodic rapid thermal cycles with controlled heating and cooling rates, optimizing the time-temperature profile to achieve fast splitting while maintaining process simplicity and repeatability
3Reliability
If high-temperature annealing is used to eliminate ion implantation defects, then most defects are eliminated, but some defects remain and processing time is long
Solution Approach 1:
The patent changes the annealing parameters by using rapid thermal processing with optimized temperature (not greater than 480°C) and time (30 seconds to 10 minutes) parameters, achieving complete defect elimination while significantly reducing processing time compared to conventional high-temperature annealing
Solution Approach 2:
The patent performs preliminary hydrogen implantation at optimized doses (1e15-1e18) and depths before bonding, creating a controlled hydrogen distribution that enables faster and more effective defect elimination during the subsequent rapid thermal processing step
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 enhances thickness uniformity, reduces surface defects, improves lattice damage, increases splitting speed, and lowers contamination, resulting in higher productivity and cost-effectiveness.
Implementation Method 1
heating the wafer to a required temperature not greater than 480° C., and keeping the temperature for 30 seconds to 10 minutes, wherein a temperature increase and decrease rate is 10-200° C./second
Implementation Method 2
applying a microwave process to the bonded wafer for 10 seconds to 20 minutes, wherein the microwave power is required to be adjusted within the range of 0-5000 W
Implementation Method 3
oxidizing one side surface of the silicon wafer raw material to obtain a silicon wafer with an oxidation layer having the thickness of >0-1000 nm
Data Source
AI summary
A method for preparing an SOI wafer by using rapid thermal processing includes: taking a silicon wafer as a raw material, sequentially performing process steps of oxidation, H+ implantation and bonding to obtain a bonded wafer with an H+ implantation layer; and then splitting the bonded wafer by using rapid thermal processing and microwaves to obtain a required SOI wafer. In the present invention, an SOI film after wafer splitting has better thickness uniformity and lower roughness. The present invention may improve lattice damage after implantation and reduce SOI surface defects after wafer splitting and thus improve the SOI surface quality. The present invention is high in wafer-splitting speed and thus reduces silicon wafer contamination. The present invention has high efficiency and an excellent comprehensive technical effect.