Water-Assisted Glass Singulation for Low-Stress Die Separation
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Solution Overview
Problem
The challenge of efficiently singulating glass substrates in semiconductor manufacturing is exacerbated by mechanical and thermal stress during cutting, leading to issues like glass delamination and breakage, especially with increasing substrate layer stacks.
Innovation Solution
A tool assembly using a laser microjet technique combined with water-assisted laser cutting and mechanical separation to remove build-up layers and perforate the glass core, ensuring minimal stress and clean separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical separation or laser cutting is used to singulate glass substrates, then the substrate can be divided into individual chips, but mechanical stress and thermal stress cause glass delamination, defects, and breakage
Solution Approach 1:
The patent replaces traditional mechanical dicing blades with a laser-based cutting system. The laser beam (particularly UV laser) ablates the glass substrate through photothermal and photomechanical effects, eliminating mechanical contact and associated stress. This substitution of mechanical cutting with optical/thermal processing resolves the contradiction by maintaining productivity while preserving substrate integrity.
Solution Approach 2:
The patent employs specific laser parameters (wavelength, pulse duration, power density) to control the cutting process. By using UV laser wavelengths that match glass absorption characteristics and optimizing pulse durations in the nanosecond to femtosecond range, the process achieves clean cuts with minimal thermal diffusion and stress, thereby maintaining both productivity and substrate integrity.
2Ease of manufacture
If traditional mechanical dicing is used, then the process is simple and cost-effective, but it causes significant mechanical stress and substrate damage
Solution Approach 1:
The patent replaces mechanical dicing blades with a laser-based cutting system. The laser beam (particularly UV laser) ablates the glass substrate through photothermal and photomechanical effects, eliminating mechanical contact and associated stress. This substitution of mechanical cutting with optical/thermal processing resolves the contradiction by maintaining productivity while preserving substrate integrity.
Solution Approach 2:
The patent introduces water as an intermediary medium in the laser cutting process. Water serves multiple functions: it absorbs excess thermal energy to prevent thermal diffusion damage, removes ablated debris from the cut zone, and cools the substrate. This intermediary approach enables effective laser cutting while minimizing harmful thermal and mechanical effects on the glass substrate.
3Manufacturing precision
If laser cutting is used to heat and cool glass rapidly, then controlled cracks can be created for separation, but thermal stress may lead to glass delamination and SeWaRe
Solution Approach 1:
The patent employs specific laser parameters (wavelength, pulse duration, power density) to control the cutting process. By using UV laser wavelengths that match glass absorption characteristics and optimizing pulse durations in the nanosecond to femtosecond range, the process achieves clean cuts with minimal thermal diffusion and stress, thereby maintaining both productivity and substrate integrity.
Solution Approach 2:
The patent introduces water as an intermediary medium in the laser cutting process. Water serves multiple functions: it absorbs excess thermal energy to prevent thermal diffusion damage, removes ablated debris from the cut zone, and cools the substrate. This intermediary approach enables effective laser cutting while minimizing harmful thermal and mechanical effects on the glass substrate.
4Device complexity
If the substrate layer stack height increases with build-up layers and devices, then device complexity and functionality improve, but cutting stress and delamination risk increase
Solution Approach 1:
The patent replaces mechanical dicing blades with a laser-based cutting system. The laser beam (particularly UV laser) ablates the glass substrate through photothermal and photomechanical effects, eliminating mechanical contact and associated stress. This substitution of mechanical cutting with optical/thermal processing resolves the contradiction by maintaining productivity while preserving substrate integrity.
Solution Approach 2:
The patent introduces water as an intermediary medium in the laser cutting process. Water serves multiple functions: it absorbs excess thermal energy to prevent thermal diffusion damage, removes ablated debris from the cut zone, and cools the substrate. This intermediary approach enables effective laser cutting while minimizing harmful thermal and mechanical effects on the glass substrate.
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 achieves high-quality cut-edges, reduces debris, and enhances manufacturing yields by minimizing mechanical and thermal stress, thereby improving the efficiency and reliability of semiconductor panel singulation.
Implementation Method 1
a laser source with an optical system configured to operate in a wet environment to remove material from the build-up layers and perforate the glass core
Implementation Method 2
directing flowing water to the workpiece
Implementation Method 3
water delivery component including an outlet nozzle that directs water to the workpiece
Data Source
AI summary
According to the various aspects, a present tool assembly or apparatus includes a water delivery component configured to direct water to a workpiece, and a cutting component for removing material to form cut-streets for die singulation. The present tool assembly is configured to operate to remove build-up layers and other layers from a glass core of the workpiece in a wet environment and a dry environment, at cut-street locations, and perform methods for dicing the workpiece.