Flip-Chip LED Multi-Layer Reflective Structure
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Solution Overview
Problem
Conventional flip-chip LED manufacturing processes require multiple masks and multiple times of physical vapor deposition (PVD) to form multi-layer reflective layers, increasing production time and cost, which hampers mass-production and market competitiveness.
Innovation Solution
A flip-chip LED is manufactured using the same mask for all layers of the multi-layer reflective layer, with a single pumping and venting process during PVD, simplifying the process and reducing costs, and optionally incorporating a conductive reflective layer for improved thermal conductivity and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks and multiple times of PVD are used to form multi-layer reflective layers, then the reflective layer structure is complete, but production time and cost increase
Solution Approach 1:
The patent combines multiple PVD processes into a single continuous process by using one mask for all layers. The multi-layer reflective layer (including Ag, Al, and Cu layers) is deposited in one vacuum cycle without breaking vacuum or changing masks, merging what were previously separate deposition steps into a unified process.
Solution Approach 2:
A single mask structure is designed to serve multiple functions simultaneously - it defines patterns for all three reflective layers (Ag, Al, Cu) and allows all depositions to proceed through one continuous process. The mask becomes a universal tool for the entire multi-layer deposition sequence rather than requiring separate masks for each layer.
2Manufacturing precision
If multiple masks and multiple times of PVD are used to form multi-layer reflective layers, then the reflective layer structure is complete, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple PVD processes into a single continuous process by using one mask for all layers. The multi-layer reflective layer (including Ag, Al, and Cu layers) is deposited in one vacuum cycle without breaking vacuum or changing masks, merging what were previously separate deposition steps into a unified process.
Solution Approach 2:
The patent eliminates the need to discard and replace masks between deposition steps. By using a single mask for the entire multi-layer deposition process, the system avoids the cost and time associated with mask replacement, vacuum breaking, and process re-setup that would occur with multiple separate deposition steps.
3Illumination intensity
If conventional multi-layer reflective layer process is used, then light reflection is achieved, but heat dissipation is insufficient
Solution Approach 1:
The patent employs a composite multi-layer reflective structure consisting of Ag, Al, and Cu layers deposited in sequence. Each material contributes different properties: Ag provides high reflectivity, Al adds reflective capability and thermal conductivity, and Cu enhances thermal management. This composite structure simultaneously achieves superior light reflection and improved heat dissipation performance.
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 simplifies the manufacturing process, reduces production costs, and enhances thermal conductivity and heat dissipation, making it suitable for high-power LED chips and packages.
Implementation Method 1
The multi-layer reflective layer is formed on the outer surface of the LED (except the outer surface of the LED disposed with exposed electrodes) by physical vapor deposition (PVD) with the same mask at one time
Data Source
AI summary
A flip-chip LED, a method for manufacturing the same and a flip-chip LED package are revealed. The LED includes at least one multi-layer reflective layer covered over the outermost layer thereof. The multi-layer reflective layer includes non-conductive reflective layer or combination of the non-conductive reflective layer with conductive reflective layer. The multi-layer reflective layer is manufactured by physical vapor deposition (PVD) with a mask at one time. The mask is used to form a pattern of the multi-layer reflective layer. Thus a photoresist layer is further formed on surface of exposed electrodes. Then a pumping and venting process is used only once during to complete vacuum deposition of each layer of the multi-layer reflective layer in turn.