Semiconductor Light Emitting Device Multilayer Metal Pillars
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Solution Overview
Problem
Semiconductor light emitting devices with chip size package structures face challenges in productivity due to difficulties in processing soft metal pillars, such as copper, which leads to uneven shape and reduced yield during grinding processes.
Innovation Solution
Implementing a multilayer structure for the metal pillars, including a softer metal like copper and a harder metal like nickel or titanium, which improves the hardness and reduces shape unevenness, allowing for more efficient grinding and increased productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft metal pillars (copper) are used, then electrical conductivity is improved, but manufacturing precision deteriorates due to uneven shape during grinding
Solution Approach 1:
The patent applies composite materials by creating a multilayer metal pillar structure consisting of a copper layer (for electrical conductivity) and a nickel layer (for hardness and shape control). This composite structure allows the copper to provide excellent electrical conductivity while the nickel layer prevents deformation and maintains uniform shape during grinding processes, thereby resolving the contradiction between conductivity and manufacturing precision.
Solution Approach 2:
The patent applies local quality by assigning different functional properties to different layers of the metal pillar. The copper layer is positioned to provide electrical conductivity where needed, while the nickel layer is positioned to provide hardness and dimensional stability during processing. This localized functional distribution allows each layer to optimize its specific role, resolving the contradiction between softness for conductivity and hardness for shape control.
2Ease of manufacture
If soft metal pillars are used, then ease of manufacture is improved, but productivity deteriorates due to extended processing time
Solution Approach 1:
The multilayer composite structure of copper and nickel pillars provides both ease of manufacture and high productivity. The nickel layer makes the pillars harder and more resistant to deformation during handling and processing, making them easier to manufacture with consistent shapes. Simultaneously, the improved shape uniformity reduces rework and defect rates, thereby increasing overall productivity despite the additional layer.
Solution Approach 2:
The patent applies parameter changes by modifying the physical properties of the metal pillar through the addition of a nickel layer. This changes the hardness parameter of the pillar, making it more resistant to deformation during processing. This parameter change enables faster processing speeds and reduced handling time, thereby improving productivity while maintaining ease of manufacture.
3Manufacturing precision
If multilayer structure is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies composite materials with a simple two-layer structure of copper and nickel. This relatively simple composite structure achieves high manufacturing precision by combining the advantages of both materials. The simplicity of having only two layers minimizes the increase in device complexity while still providing the benefits of improved shape uniformity and reduced deformation during processing.
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a semiconductor layer, a first metal pillar, a second metal pillar, and an insulating layer. The semiconductor layer includes a first surface, a second surface, and a light emitting layer. The first metal pillar is electrically connected to the second surface. The first metal pillar includes first and second metal layers. The first metal layer is provided between the second surface and at least a part of the second metal layer. The second metal pillar is arranged side by side with the first metal pillar, and electrically connected to the second surface. The second metal pillar includes third and fourth metal layers. The third metal layer is provided between the second surface and at least a part of the fourth metal layer. The insulating layer is provided between the first and second metal pillars.