LED Micro-bump Flip-Chip Bonding for Thermal Resistance Reduction
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Solution Overview
Problem
High power light-emitting diodes (LEDs) face challenges with heat dissipation due to poor light extraction efficiency, leading to increased temperature and reliability issues, as traditional methods like flip-chip bonding with gold stud bumps restrict thermal resistance and bonding performance.
Innovation Solution
A light-emitting element with electrodes featuring a plurality of micro-bumps for direct flip-chip bonding to a submount, allowing for improved heat dissipation through a short bonding distance and increased bonding area, reducing thermal resistance and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional gold stud bump method is used for flip-chip bonding, then bonding process is established, but bonding area is limited and thermal resistance is high
Solution Approach 1:
The electrode is divided into multiple micro-bumps instead of using a single gold stud bump. This segmentation increases the total bonding area while maintaining the flip-chip bonding process, allowing better thermal and electrical contact between the LED and submount.
Solution Approach 2:
The bonding interface is transformed from a single-point contact (gold stud) to a distributed array of micro-bumps across the electrode surface. This dimensional change from 0D/1D contact to 2D distributed contact significantly increases the effective bonding area and reduces thermal resistance.
2Reliability
If gold stud bump method is used, then bonding is achieved, but bonding distance is long and heat dissipation is poor
Solution Approach 1:
The single long bonding path of the gold stud is segmented into multiple shorter micro-bump connections. Each micro-bump creates a shorter thermal and electrical path from the LED electrode to the submount, reducing overall bonding distance and improving heat dissipation.
3Reliability
If gold stud bump method is used, then bonding is achieved, but thermal resistance is high restricting high power application
Solution Approach 1:
The thermal path is segmented into multiple parallel micro-bump channels, distributing the heat flow across many small contact points. This segmentation reduces thermal resistance by providing multiple parallel thermal conduction paths from the LED to the submount.
Solution Approach 2:
The thermal contact is transformed from a single-point interface to a distributed 2D array of micro-bump contacts. This dimensional expansion significantly increases the effective thermal contact area, reducing thermal resistance and enabling better heat dissipation for high power applications.
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 direct bonding method using micro-bumps on the electrodes effectively reduces thermal resistance and increases luminance, enabling higher current flux and improved heat dissipation, thus addressing the limitations of traditional gold stud bonding.
Implementation Method 1
Through thermosonic bonding method, ultrasonic wave is provided on the junction of the solder bumps 24 of the submount unit 20 and electrodes 15 and 16 of the LED 10 to make the junction quickly rub to produce high heat for melting and bonding.
Implementation Method 2
ultrasonic wave is provided on the junction of the solder bumps 24 of the submount unit 20 and electrodes 15 and 16 of the LED 10 to make the junction quickly rub to produce high heat for melting and bonding.
Data Source
AI summary
This invention provides a light-emitting element and the manufacture method thereof. The light-emitting element is suitable for flip-chip bonding and comprises an electrode having a plurality of micro-bumps for direct bonding to a submount. Bonding within a relatively short distance between the light-emitting device and the submount can be formed so as to improve the heat dissipation efficiency of the light-emitting device.