Laser Debonding Feedback Control for Damage-Free Substrate Separation
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Solution Overview
Problem
Laser debonding methods often result in destruction of expensive functional components due to excessive energy input, necessitating a method for effective and damage-free separation of temporarily bonded substrate stacks.
Innovation Solution
The method involves evaluating and optimizing laser parameters during the debonding process by monitoring and adapting the laser parameters in situ, using sensors to detect reflected and transmitted laser beams, and adjusting the laser energy to minimize thermal and photothermal loads on the substrate, thereby reducing the bonding layer's adhesive strength without damaging the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high power laser beams are used for substrate stack separation, then separation efficiency is improved, but substrate damage increases
Solution Approach 1:
The patent implements a feedback mechanism by detecting reflected and transmitted laser beams during the debonding process. Sensors monitor the laser beam characteristics in real-time, and this information is fed back to the control system to dynamically adjust laser parameters, ensuring effective separation while preventing substrate damage through continuous monitoring and adaptation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting laser power, pulse duration, and scanning speed based on real-time detection of the debonding process. The control system modifies these parameters during operation to optimize the balance between separation efficiency and substrate protection, transitioning from static to adaptive parameter control.
2Reliability
If sufficient laser energy is introduced to destroy the bonding layer, then separation effectiveness is improved, but thermal load on functional components increases
Solution Approach 1:
The patent applies local quality by concentrating laser energy precisely at the bonding layer interface through focused beam delivery and controlled scanning patterns. The energy is localized to the specific region requiring debonding, minimizing thermal diffusion to surrounding functional components while ensuring sufficient energy density at the target interface for effective separation.
Solution Approach 2:
The patent implements skipping by using pulsed laser delivery with optimized pulse durations that deliver sufficient energy to destroy the bonding layer before significant thermal diffusion can occur to functional components. The rapid pulsed action allows the energy to be deposited and utilized at the target interface before heat has time to spread to sensitive areas.
3Manufacturing precision
If laser parameters are optimized for complete bonding layer destruction, then separation quality is improved, but risk of substrate surface damage increases
Solution Approach 1:
The patent applies partial action by delivering just sufficient laser energy to achieve complete bonding layer destruction without excessive energy that would damage the substrate surface. The system monitors the debonding process in real-time and adjusts parameters to provide the minimum necessary energy for effective separation, avoiding over-irradiation that could harm the substrate while ensuring complete bonding layer destruction.
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 enables efficient and damage-free separation of substrate stacks by ensuring the correct energy input for bonding layer weakening, maintaining the integrity of functional components and allowing for high-volume manufacturing with minimal control work.
Implementation Method 1
a focused laser beam with high power and defined wavelength scans the substrate stack interface region of two substrates and leads to a separation of the two substrates from one another as a result of the high energy input into the bonding layer
Implementation Method 2
the introduced energy of the laser beams leads to the at least partial weakening (preferable complete reduction) of the bonding strength of the temporary bonding layer. Since, as a result of the irradiation, the targeted energy input and the energy conversion takes place in the bonding layer, the in particular thermal and/or photothermal load on the functional components is minimised
Implementation Method 3
a focused laser beam with high power and defined wavelength scans the substrate stack interface region
Implementation Method 4
For the evaluation of the correct laser parameters, reflected laser beams and/or laser beams transmitted through the substrate stack are detected
Implementation Method 5
reflected laser beams and/or laser beams transmitted through the substrate stack are detected, according to the invention, in particular in situ during the bombardment of the substrate stack with laser beams
Data Source
AI summary
A method for separating a temporarily bonded substrate stack by bombardment of a joining layer of the substrate stack by means of laser beams emitted by a laser, characterised in that laser beams of the laser reflected and/or transmitted at the temporarily bonded substrate stack are detected during the bombardment of the joining layer with the laser beams. The invention also relates to a corresponding device.