Acoustic Substrate Split Detection During SMART CUT Annealing
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Solution Overview
Problem
Current methods for detecting substrate splitting during the SMART CUT process, such as using piezoelectric sensors, face challenges in ensuring mechanical linkage, temperature limitations, contamination risks, and inability to accurately determine splitting energy or characteristics, leading to inefficiencies and potential damage to wafers.
Innovation Solution
Recording and analyzing sound emitted during substrate splitting using microphones placed inside or near the heating chamber allows precise detection of splitting time, energy release, and breakage, enabling accurate monitoring of each substrate in a batch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric sensors are used to detect substrate splitting, then splitting detection capability is provided, but mechanical linkage is difficult to ensure and temperature limitations occur
Solution Approach 1:
The patent replaces the mechanical piezoelectric sensor system with an acoustic detection system using microphones. Instead of requiring mechanical linkage between the substrate and sensor, the system detects splitting events through acoustic emissions in the gas phase within the furnace chamber, eliminating mechanical linkage requirements and temperature limitations of piezoelectric sensors.
2Measurement precision
If piezoelectric sensors are placed in direct contact with substrates, then splitting detection is enabled, but contamination of substrates occurs
Solution Approach 1:
The patent introduces the acoustic field as an intermediary between the substrate and the detection device. The microphone detects splitting events through sound waves propagating through the gas phase, serving as a non-contact intermediary that enables detection without direct contact between the sensor and substrate, thus preventing contamination.
3Reliability
If the annealing process continues until all wafers are split, then complete processing is achieved, but thermal budget increases causing potential damage
Solution Approach 1:
The patent implements a feedback control system where real-time acoustic detection of splitting events provides information to the control unit. The control unit monitors the number of split wafers and automatically stops the annealing process when all wafers have split, creating a closed-loop feedback system that prevents excessive thermal exposure while ensuring complete processing.
4Productivity
If automated separation is performed without verifying substrate splitting, then processing efficiency is maintained, but unsplit substrates cause machine blockage
Solution Approach 1:
The patent performs preliminary detection of substrate splitting status before the separation step by continuously monitoring acoustic emissions during annealing. The control unit identifies which substrates have split and which have not, enabling selective processing and preventing unsplit substrates from entering the automated separation machine, thus avoiding blockages while maintaining efficiency.
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 provides precise detection of substrate splitting and breakage, optimizing the annealing process by minimizing thermal budget, preventing damage, and ensuring efficient processing, while allowing for the determination of splitting characteristics like energy and speed.
Implementation Method 1
detecting, in the recording, a sound emitted by the substrate during the splitting thereof along its weakened zone
Data Source
AI summary
A method for monitoring a heat treatment applied to a substrate comprising a weakened zone formed by implanting atomic species for splitting the substrate along the weakened zone, the substrate being arranged in a heating chamber, the method comprising recording sound in the interior or in the vicinity of the heating chamber and detecting, in the recording, a sound emitted by the substrate during the splitting thereof along the weakened zone. A device for the heat treatment of a batch of substrates comprises an annealing furnace comprising a heating chamber intended to receive the batch, at least one microphone configured to record sounds in the interior or in the vicinity of the heating chamber, and a processing system configured to detect, in an audio recording produced by the microphone, a sound emitted when a substrate splits.