Acoustic Cleaving Enclosure for Controlled Semiconductor Layer Transfer
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Solution Overview
Problem
Current semiconductor manufacturing techniques for layer transfer, such as laser lift-off and spalling, face challenges in maintaining device layer growth quality and are costly due to substrate removal, with sound-assisted crack propagation methods requiring precise control to avoid surface variations.
Innovation Solution
An acoustic cleaving apparatus that includes a crack initiator system, a base stress system, and an acoustic system to control crack propagation in semiconductor substrates, utilizing a laser for indentation, piezoelectric devices for acoustic energy, and an acoustic enclosure to manage wave interaction, enabling controlled fracture and substrate reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If laser lift-off is used to remove substrates, then substrate removal is achieved, but device layer growth quality is affected due to intermediate layers
Solution Approach 1:
The patent extracts and removes the substrate from the device layer structure through controlled crack propagation, allowing the device layer to be separated without intermediate layers that would affect subsequent growth quality. The crack initiator and acoustic system enable direct substrate removal without leaving residual materials.
Solution Approach 2:
The patent introduces a crack initiator as an intermediary element that facilitates substrate removal. This initiator creates a controlled crack that propagates through the substrate, enabling clean separation without direct mechanical contact that would compromise the device layer or leave intermediate materials.
2Strength
If spalling is performed at high temperatures, then substrate cleaving is achieved, but surface conditions show significant variation
Solution Approach 1:
The patent applies periodic acoustic waves at controlled frequencies to propagate cracks through the substrate. This periodic acoustic action enables precise control of crack propagation, achieving clean cleavage without the thermal variations and surface inconsistencies associated with high-temperature spalling methods.
Solution Approach 2:
The patent replaces the thermal-mechanical spalling process with an acoustic wave-based system. Instead of using high-temperature thermal fields to induce stress and cleavage, the system uses controlled acoustic waves to propagate cracks, eliminating thermal damage and surface variation while maintaining effective substrate separation.
3Manufacturing precision
If sound-assisted crack propagation is used, then controlled cracking is achieved, but precise control is required to avoid surface variations
Solution Approach 1:
The patent performs preliminary actions by positioning the crack initiator and applying base stress before the acoustic waves are activated. This preliminary setup establishes the stress state and crack initiation point, allowing the subsequent acoustic waves to propagate the crack in a controlled manner without requiring complex real-time control during the actual cracking process.
Solution Approach 2:
The patent segments the crack propagation process into distinct phases: crack initiation by the initiator, crack propagation driven by acoustic waves, and crack completion. This segmentation allows each phase to be controlled independently, simplifying the overall control system while maintaining high precision in the final cleavage result.
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
The acoustic cleaving apparatus effectively transfers semiconductor layers with improved control over crack propagation, reducing substrate costs and maintaining device layer quality, allowing for efficient reuse of substrates in semiconductor manufacturing.
Implementation Method 1
a crack initiator system to create an indentation on a workpiece... the laser can be directed toward a top surface or a back side (or side surface) of the workpiece
Implementation Method 2
an acoustic generator that includes an array of piezoelectric devices
Implementation Method 3
an acoustic system to emit acoustic waves into the workpiece to maintain a controlled crack propagation through a material of the workpiece
Data Source
AI summary
An acoustic cleaving system are described for initiating and controlling crack propagation. In an embodiment, the system includes an acoustic generator that includes a piezoelectric device; a high-voltage power supply; and an acoustic cleaving circuit. The acoustic cleaving circuit includes a push-pull circuit coupled to the piezoelectric device and coupled to the high-voltage power supply, and a capacitor bank that includes one or more capacitors coupled in parallel to the push-pull circuit. In one embodiment, the push-pull circuit is for receiving at least one input signal and for producing an amplified output signal to drive the piezoelectric device.