Laser Element Junction-Down Mounting for Heat Dissipation
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Solution Overview
Problem
Semiconductor lasers face challenges in heat dissipation and efficiency due to increased heat generation with higher output, requiring improved methods to manage heat and reduce electrical resistance.
Innovation Solution
A method of manufacturing a light emitting device involves bonding a semiconductor element structure to a second substrate, thinning the first substrate, and mounting the laser element on a heat dissipating member to enhance heat dissipation and reduce electrical resistance by eliminating the second substrate, which allows for closer proximity of the heat source to the dissipating member and reduces overall electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output of semiconductor laser is increased, then the light emission performance is improved, but the heat generation increases
Solution Approach 1:
The patent removes the first substrate from the laser element structure through selective etching, extracting the harmful thermal resistance component. This extraction allows the laser element to be mounted directly on the heat dissipating member, improving heat dissipation while maintaining high output performance.
Solution Approach 2:
The patent changes the mounting orientation from conventional side-mounting to bottom-mounting (junction-down mounting), where the laser element is mounted on its lower surface directly to the heat dissipating member. This dimensional change in mounting approach creates a direct thermal pathway, significantly improving heat dissipation efficiency.
2Temperature
If the first substrate is removed to improve heat dissipation, then the thermal resistance is reduced, but the mechanical support is weakened
Solution Approach 1:
The laser element structure is designed and formed on the first substrate before the substrate is removed. The semiconductor layers, ridges, and electrode structures are preliminarily created with proper mechanical integrity, ensuring that the structure can withstand the substrate removal process and subsequent handling without mechanical failure.
Solution Approach 2:
The heat dissipating member serves as an intermediary that provides both thermal management and mechanical support functions. By mounting the laser element directly to this robust component, the system gains the mechanical strength previously provided by the substrate while achieving superior heat dissipation.
3Stability of the object's composition
If the second substrate is kept in place, then the structural stability is maintained, but the electrical resistance increases
Solution Approach 1:
The second substrate is selectively removed from regions where it creates electrical resistance, particularly from the laser element structure. This extraction eliminates the electrical resistance barrier while the remaining second substrate maintains structural stability in areas where it provides support without interfering with electrical conduction.
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 results in improved heat dissipation performance and increased efficiency of the light emitting device by reducing thermal resistance and driving voltage, while also allowing the use of inexpensive materials for the second substrate.
Implementation Method 1
laser element structure having ridges on a side opposite to the first substrate and raising layers respectively formed above the ridges
Implementation Method 2
mounting the laser element with the second substrate on a heat dissipating member such that a laser element side of the laser element with the second substrate faces the heat dissipating member
Data Source
AI summary
A method of manufacturing a light emitting device comprising: providing an element-structure wafer having a first substrate and a laser element structure on the first substrate, the laser element structure having ridges on a side opposite to the first substrate and raising layers respectively formed above the ridges; bonding a laser element structure side of the element-structure wafer to a second substrate to obtain a bonded wafer; removing at least a portion of the first substrate to obtain a thinned bonded wafer; singulating the thinned bonded wafer to obtain a laser element with the second substrate; mounting the laser element with the second substrate on a heat dissipating member such that a laser element side of the laser element with the second substrate faces the heat dissipating member; and removing the second substrate from the laser element.