Stealth Dicing Laser Phase Control to Minimize Substrate Chipping
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Solution Overview
Problem
Existing cutting methods using thin cutting blades for dividing semiconductor substrates often result in chipping, leading to performance degradation of the divided chips.
Innovation Solution
A stealth dicing laser device that generates laser light with controlled phase transformation using a pulse laser generator, condenser lens, and pupil filters, optimized through a controller and optimizer to minimize splash defects and maintain high peak intensity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thin cutting blade with diamond abrasive grains is used to cut the substrate, then the substrate can be divided into individual chips, but chipping occurs at the front-side or back-side of the substrate resulting in performance degradation
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a laser-based stealth dicing system. The laser device generates laser light that interacts with the substrate to form a stealth dicing layer internally, eliminating the need for mechanical contact and thus preventing chipping at the substrate surfaces while maintaining high division efficiency
Solution Approach 2:
The patent transforms the phase of laser light using pupil filters before it passes through the condenser lens. By controlling the phase parameters of the laser light (using Zernike polynomials for phase transformation), the system optimizes the laser beam's interaction with the substrate to prevent splash defects and chipping while maintaining cutting effectiveness
2Manufacturing precision
If laser light is used to form a stealth dicing layer in silicon substrate, then chipping and splash defects are minimized, but phase control of laser light is required to optimize the process
Solution Approach 1:
The patent introduces pupil filters as intermediary components in the optical path between the laser source and the substrate. These pupil filters act as mediators that transform the phase of the laser light, enabling precise control over the laser beam's interaction with the substrate to minimize splash defects and optimize cutting quality
Solution Approach 2:
The patent applies phase transformation to the laser light before it reaches the substrate through the condenser lens. By pre-modifying the laser beam's phase characteristics using pupil filters (based on Zernike polynomial parameters), the system prepares the optimal light distribution pattern in advance to prevent defects during the actual cutting process
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 laser device effectively forms a stealth dicing layer in silicon substrates without damaging the front or back sides, minimizing splash defects and enhancing cutting quality by controlling laser light interaction with previously formed cracks.
Implementation Method 1
a pulse laser generator configured to generate laser light
Implementation Method 2
laser light emitted from a laser device is condensed in the vicinity of a concentration point inside a substrate
Implementation Method 3
a pupil filter configured to transform a phase of the laser light before the laser light passes through the condenser lens
Data Source
AI summary
A stealth dicing laser device including: a pulse laser generator configured to generate laser light; a condenser lens formed in an optical path of the laser light; a pupil filter configured to transform a phase of the laser light before the laser light passes through the condenser lens; and a controller configured to provide a phase control signal to the pupil filter, wherein the pupil filter transforms the phase of the laser light based on the phase control signal, wherein the phase control signal is a signal transforming a phase expression of the laser light based on a parameter.