Light-Emitting Element Dielectric Stack for Crack-Controlled Dicing
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Solution Overview
Problem
The challenge in the field of light-emitting diode (LED) manufacturing is maintaining good optoelectronic characteristics while improving dicing yield as LED devices become smaller, particularly in ensuring symmetrical and uniform light emission and minimizing unintended cracks during the dicing process.
Innovation Solution
A method involving a base with a semiconductor stack, an isolation region, and a dielectric stack is used, where a laser with specific wavelengths is applied to modify the base and dielectric stack to form holes that serve as a pre-defined dicing line, reducing unintended cracks and enhancing light extraction efficiency by forming modified regions on the side walls and using a dielectric stack with controlled reflectance and transmittance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the light-emitting diode device becomes smaller, then the compact size is improved, but the dicing yield deteriorates and unintended cracks occur
Solution Approach 1:
The patent applies preliminary action by forming modified regions in the base before the dicing process. These modified regions are created through laser irradiation that generates thermal stress, pre-weakening the base along intended dicing lines. This allows the dicing process to proceed cleanly along predetermined paths without causing unintended cracks in the smaller LED devices, thereby maintaining high dicing yield despite reduced device size.
Solution Approach 2:
The patent implements local quality by creating modified regions with distinct thermal and mechanical properties in specific locations of the base. The laser irradiation selectively modifies only the regions where dicing lines will be formed, creating localized zones with different stress characteristics. This localized modification enables precise control over where cracks will form during dicing, allowing small LED devices to be separated cleanly without affecting the overall structural integrity or causing unintended damage.
2Volume of moving object
If the size of the light-emitting diode device becomes smaller, then the compact size is improved, but the optoelectronic characteristics deteriorate
Solution Approach 1:
The patent uses preliminary action to form modified regions that serve as stress relief zones before dicing. By pre-establishing these controlled modification zones through laser irradiation, the structural stress in smaller LED devices is redistributed and managed. This prevents stress concentration that would otherwise degrade optoelectronic characteristics, allowing miniaturized devices to maintain their optical and electrical performance.
Solution Approach 2:
The patent applies local quality by creating spatially differentiated regions in the base with distinct properties. The modified regions have altered thermal and mechanical characteristics that differ from the unmodified areas. This localized property variation enables the base to better accommodate thermal expansion and stress distribution in smaller LED devices, thereby preserving optoelectronic characteristics despite size reduction.
3Ease of manufacture
If laser irradiation is applied to the base, then the dicing process is improved, but the semiconductor stack may be damaged
Solution Approach 1:
The patent introduces an intermediary approach by using dielectric stacks with specific optical properties as a protective layer between the laser and the semiconductor stack. The dielectric stack's reflectance and transmittance characteristics are engineered to allow the laser to effectively modify the base while preventing excessive energy from reaching and damaging the semiconductor stack. This intermediary structure enables clean dicing without compromising device integrity.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the optical parameters of the dielectric stack, specifically its reflectance and transmittance at the laser wavelength. By adjusting these parameters, the system optimizes the balance between allowing sufficient laser energy to reach the base for effective modification and blocking excessive energy that would damage the semiconductor stack. This parameter optimization enables safe and effective dicing.
4Illumination intensity
If a dielectric stack with controlled reflectance and transmittance is used, then the light extraction efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent implements universality by designing the dielectric stack to perform multiple functions simultaneously. The same dielectric stack structure that provides optical enhancement for light extraction also serves as a protective layer during laser dicing and as part of the overall device packaging. By combining these functions into a single integrated component, the patent avoids the need for separate structures, thereby reducing overall device complexity while achieving improved light extraction efficiency.
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 improves the brightness and uniformity of light emission, reduces unintended cracks, and enhances the dicing yield by creating symmetrical emission angles and protecting the semiconductor stack from laser damage, thereby maintaining the optoelectronic quality of the LEDs.
Implementation Method 1
the dielectric stack has a reflectance of 10%-50% and/or a transmittance of 50%-90% for the first wavelength
Implementation Method 2
the dielectric stack has a reflectance of 10%-50% and/or a transmittance of 50%-90% for the first wavelength
Implementation Method 3
applying a first laser having a first wavelength to irradiate the base along the isolation region
Implementation Method 4
applying a first laser having a first wavelength to irradiate the base along the isolation region
Data Source
AI summary
A method of manufacturing a light-emitting element, includes: providing a base having an upper surface and a lower surface; forming a semiconductor stack on the upper surface; removing part of the semiconductor stack to form an isolation region surrounding the semiconductor stack; forming a dielectric stack covering the semiconductor stack and the isolation region; and applying a first laser having a first wavelength to irradiate the base along the isolation region; wherein the dielectric stack has a reflectance of 10%-50% and/or a transmittance of 50%-90% for the first wavelength.