Interposer with Aluminum Film and AuSn Layer for LED Mounting
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Solution Overview
Problem
The existing interposers between light emitting elements and circuit boards are costly to produce and maintain, with a need for cost reduction while ensuring effective electrical connection and light reflection.
Innovation Solution
An interposer with a silicon substrate, silicon oxide film, and an aluminum film pattern, featuring laminated structures of Ni, Pd, and Au films for element mounting and terminal sections, and an AuSn layer for bonding, along with a protective film for optical permeability and reflectivity, is developed to reduce costs and enhance reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold films are used extensively for wiring patterns and mounting sections, then electrical connection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by using laminated Ni-Pd-Au films only at critical locations (element mounting sections and terminal sections) where electrical connection reliability is most important, while using aluminum films for general wiring patterns where cost reduction is prioritized. This selective application of expensive materials resolves the contradiction between reliability and manufacturing cost.
Solution Approach 2:
The patent segments the interposer surface into different functional zones: critical connection areas with laminated Ni-Pd-Au films and general wiring areas with aluminum films. This segmentation allows differential material application, maintaining reliability where needed while reducing overall manufacturing cost.
2Ease of manufacture
If aluminum film is used for wiring patterns instead of gold film, then manufacturing cost is reduced, but reflectivity performance may be affected
Solution Approach 1:
The patent applies local quality by forming aluminum films with specific properties for general wiring patterns where cost reduction is important, while using laminated Ni-Pd-Au films at critical locations. The aluminum film thickness and properties are locally optimized to provide adequate reflectivity for non-critical areas while maintaining cost effectiveness.
3Reliability
If AuSn layer is formed on element mounting sections, then joining performance with light emitting elements is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the AuSn layer on the aluminum film at element mounting sections before mounting the light emitting elements. This advance preparation ensures optimal joining performance by creating the appropriate metallurgical interface in advance, while the layer is formed using standard sputtering or electroplating processes that integrate into existing manufacturing workflows.
4Illumination intensity
If protective film with optical permeability is added, then light transmission is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the protective film to serve multiple purposes: protecting the aluminum film from oxidation and damage, providing optical permeability for light transmission, and potentially serving as an adhesion layer. This consolidation of functions into a single layer minimizes device complexity while achieving multiple performance goals.
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 interposer achieves cost reduction by minimizing Au usage, maintaining reflectivity, and ensuring reliable electrical connections and light reflection, while stabilizing the AuSn composition for improved joining performance.
Implementation Method 1
The surface of the aluminum film having the predetermined pattern forms, around each of the element mounting sections, a reflecting surface that reflects light
Implementation Method 2
an AuSn layer is formed on a predetermined region of a surface of the Au film in each of the element mounting sections
Data Source
AI summary
An interposer includes element mounting sections and terminal sections directly and partly formed on a surface of an aluminum film having the predetermined pattern. Each of the element mounting sections and the terminal sections has a laminated structure of an Ni film, an Pd film and an Au film. The interposer is formed with an AuSn layer on a predetermined region of a surface of each Au film in the element mounting sections. The interposer includes a protective film having optical permeability that directly covers a region of the surface of the aluminum film, which is out of contact with the element mounting sections and the terminal sections.