Selective Laser-Assisted Die Transfer for Precision Assembly
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Solution Overview
Problem
Existing laser-induced forward transfer methods for assembling small components, such as semiconductor dice, face challenges with positioning accuracy and safety due to the stochastic nature of ablative mechanisms, which can damage fragile components and limit high-throughput processing.
Innovation Solution
The Thermo-Mechanical Selective Laser Assisted Die Transfer (tmSLADT) method uses a dual polymeric dynamic release layer with a blistering layer and an adhesive layer to gently transfer ultra-thin components by creating a controlled blister with low-energy laser pulses, allowing for precise and safe placement without rupturing the blister and damaging the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ablative laser release is used to transfer articles contactlessly, then transfer speed is improved, but positioning precision deteriorates due to stochastic release dynamics and flight instability
Solution Approach 1:
The patent replaces the ablative mechanism (which uses vaporized material plume to eject articles) with a thermal expansion mechanism. The dynamic release layer expands thermally in response to laser heating, gently propelling articles toward the receiving substrate without stochastic ejection, thereby maintaining both high transfer speed and placement precision.
Solution Approach 2:
The patent changes the physical mechanism from ablative ejection to controlled thermal expansion. By adjusting laser parameters and the composition of the dynamic release layer, the system achieves predictable, consistent article transfer with high placement precision while maintaining fast transfer speeds.
2Manufacturing precision
If contact transfer is used to improve placement precision, then positioning accuracy is improved, but the risk of mechanical damage and process complexity increases
Solution Approach 1:
The patent introduces a dynamic release layer as an intermediary between the carrier and the receiving substrate. This layer thermally expands to gently propel articles through a small gap, achieving contactless transfer with high precision while eliminating mechanical damage risks associated with direct contact transfer.
Solution Approach 2:
The patent replaces mechanical contact transfer with a thermal expansion-based propulsion mechanism. The dynamic release layer's thermal expansion provides controlled, gentle force to transfer articles precisely without mechanical impact or damage.
3Productivity
If ablative mechanism with high-energy laser is used, then transfer speed is improved, but the risk of damaging fragile components increases
Solution Approach 1:
The patent changes the laser energy parameters from high-energy ablative regime to lower-energy thermal expansion regime. This allows fast transfer rates while using gentler thermal forces that do not damage fragile components like ultra-thin semiconductor dice.
Solution Approach 2:
The patent substitutes the harsh ablative mechanism with a gentle thermal expansion mechanism. The dynamic release layer's controlled expansion provides sufficient propulsion force for high-speed transfer without the destructive effects of high-energy laser ablation on fragile components.
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 enables high-throughput, precise, and safe assembly of ultra-thin semiconductor dice and other small components, achieving placement speeds several orders of magnitude higher than conventional pick-and-place machines, with improved accuracy and reduced damage risk.
Implementation Method 1
focusing a low-energy laser pulse, or pulses, on a blistering layer within the dynamic release layer to form a blister
Implementation Method 2
the expansion of the blister the article is mechanically translated
Implementation Method 3
The laser beam (e.g., pulse or pulses) creates a blister in the DRL that is thicker than its laser absorption depth, thus confining the vaporized material within the blister
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Electronic components are often assembled using robotic equipment, such as pick-and-place machines, that is not optimized for components such as ultra-thin semiconductor bare dice. Selective laser-assisted die transfer is described based on the unique blistering behavior of a multilayer dynamic release layer when irradiated by low energy focused laser pulse(s) in which the blister creates translation of the article being placed. Accurate placement results are provided with negligible lateral and angular displacement.