Laser Beam Modulation for Scatter-Free Substrate Dicing
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Solution Overview
Problem
Conventional laser dicing devices often cause scattering of the laser beam due to spatial overlap with pre-formed modified regions and cracks in the substrate, leading to potential damage to semiconductor elements during the dicing process.
Innovation Solution
A method and device that modulate a Gaussian laser beam to reduce its intensity in a region surrounding a line parallel to the dicing direction, preventing spatial overlap with pre-formed modified regions and cracks, thereby reducing beam scattering. This is achieved through various modulation techniques, including the use of slits, spatial light modulators, and birefringent lenses, which shape the laser beam into an 8-shaped form with low intensity along the dicing direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Gaussian laser beam is used for dicing, then the dicing process can be performed, but the laser beam spatially overlaps with pre-formed modified regions and cracks causing scattering and potential damage to semiconductor elements
Solution Approach 1:
The patent applies local quality by creating an 8-shaped laser beam intensity distribution where the intensity is selectively reduced in the region surrounding the first line (parallel to dicing direction) while maintaining higher intensity in other regions. This localized intensity modification prevents spatial overlap with pre-formed modified regions and cracks along the dicing path, thereby eliminating laser beam scattering and preventing optical damage to semiconductor elements without compromising the overall dicing effectiveness
2Reliability
If the laser beam intensity is reduced in the region surrounding the first line to prevent scattering, then beam scattering is prevented, but the dicing efficiency may be reduced
Solution Approach 1:
The 8-shaped intensity distribution selectively reduces intensity only in the critical region surrounding the first line where scattering occurs, while maintaining sufficient intensity in other regions to ensure effective dicing. This localized approach prevents beam scattering and protects semiconductor elements while preserving adequate cutting power, thus maintaining dicing efficiency
Solution Approach 2:
The patent converts the potential harm of reduced intensity (which might slow dicing) into a benefit by strategically positioning the intensity reduction only where scattering occurs. The modified intensity distribution actually improves overall process reliability and prevents damage, while the maintained intensity in non-critical regions ensures dicing continues at effective rates
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 modulation of the laser beam into an 8-shaped form effectively prevents scattering within the substrate, minimizing damage to semiconductor elements and ensuring precise dicing without compromising the integrity of the substrate's front and rear surfaces.
Implementation Method 1
modulating a shape of the emitted Gaussian laser beam by reducing intensity of the Gaussian laser beam in a region surrounding a first line passing through a center of the Gaussian laser beam in a plan view
Implementation Method 2
a focusing lens configured to focus a modulated Gaussian laser beam modulated by the laser beam modulator
Implementation Method 3
dices the substrate into individual chips by forming a modified region and a crack caused by multi-photon absorption
Data Source
AI summary
A laser dicing device includes: a Gaussian laser beam emitter configured to emit a Gaussian laser beam having a Gaussian energy distribution; a laser beam modulator configured to modulate a shape of the emitted Gaussian laser beam by reducing intensity in a region surrounding a first line parallel with a laser dicing direction of the emitted Gaussian beam, the first line crossing a center of the Gaussian laser beam in a plan view; a focusing lens configured to focus a modulated Gaussian laser beam modulated by the laser beam modulator; and a substrate support configured that a substrate to be diced is seated on the support, wherein the focusing lens is configured to collect the modulated Gaussian laser beam inside the substrate seated on the substrate support.