Laser Dicing of VLED Dies on Metal Substrates
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Solution Overview
Problem
Conventional methods for fabricating nitride-based semiconductor devices, such as LEDs, face challenges in achieving high yield and performance, particularly in separating semiconductor dies from non-conductive substrates with low thermal and electrical conductivity, which affects brightness and thermal conductivity.
Innovation Solution
A method involving laser cutting between semiconductor dies on a metal substrate, followed by physical separation, and additional processes like air knife or water jet with chemical solutions for precise dicing, enhancing the separation efficiency and reducing damage to the devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional dicing methods are used on sapphire substrates, then the separation process is simple, but the thermal conductivity and electrical conductivity are low, affecting device performance
Solution Approach 1:
The patent changes the substrate material parameter from sapphire to metal substrate, fundamentally altering the thermal and electrical conductivity parameters of the system. This enables improved heat dissipation and electrical performance while maintaining the dicing separation capability through modified cutting methods.
Solution Approach 2:
The invention uses composite structures combining metal substrates with semiconductor layers, creating a multi-layer system that leverages the high thermal and electrical conductivity of metal while maintaining the functional properties of semiconductor materials. The composite structure resolves the contradiction between ease of manufacture and device performance.
2Manufacturing precision
If laser cutting is applied to separate dies on metal substrate, then the separation precision is improved, but the process complexity increases
Solution Approach 1:
The patent replaces conventional mechanical dicing methods with laser cutting technology. The laser beam precisely cuts through the metal substrate and semiconductor layers without mechanical contact, achieving high separation precision while eliminating the need for complex mechanical dicing equipment and reducing physical stress on the devices.
Solution Approach 2:
The laser cutting process utilizes phase transitions of materials (melting and vaporization) to achieve precise separation. The concentrated laser energy rapidly heats and melts the material at the cut line, enabling clean separation with minimal mechanical intervention and reduced process complexity.
3Manufacturing precision
If physical force is applied to fully separate dies, then the separation completeness is improved, but the risk of device damage increases
Solution Approach 1:
The patent replaces forceful mechanical separation with laser-based separation. The laser cuts through the bonding layers and substrate material, allowing dies to be separated complete and cleanly without applying damaging physical forces. This eliminates the trade-off between separation completeness and device damage risk.
Solution Approach 2:
The laser beam acts as an intermediary between the cutting tool and the material, transferring energy without mechanical contact. This intermediary approach enables complete separation while avoiding the harmful mechanical forces that would directly contact and potentially damage the delicate semiconductor devices.
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 yield and performance of nitride-based semiconductor devices by enabling better separation of semiconductor dies, increasing brightness and thermal conductivity, and addressing the limitations of conventional methods.
Implementation Method 1
applying a laser between adjacent VLED dies of the plurality to cut through any semiconductor material between the adjacent VLED dies and at least a portion of the metal substrate
Data Source
AI summary
Techniques for dicing wafer assemblies containing multiple metal device dies, such as vertical light-emitting diode (VLED), power device, laser diode, and vertical cavity surface emitting laser device dies, are provided. Devices produced accordingly may benefit from greater yields and enhanced performance over conventional metal devices, such as higher brightness of the light-emitting diode and increased thermal conductivity. Moreover, such techniques are applicable to GaN-based electronic devices in cases where there is a high heat dissipation rate of the metal devices that have an original non- (or low) thermally conductive and/or non- (or low) electrically conductive carrier substrate that has been removed.