Semiconductor Light-Emitting Apparatus Electrode Isolation
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Solution Overview
Problem
Existing semiconductor light-emitting apparatuses face issues with unnecessary short-circuiting between electrodes due to the use of bonding members, particularly when the distance between p- and n-electrodes is minimized to increase output power, leading to reliability concerns and non-lighting issues under thermal stress.
Innovation Solution
A method and apparatus where the p- and n-electrodes of a semiconductor light-emitting device are bonded with bonding members to the corresponding electrodes on a supporting board, with the p-electrode being formed substantially entirely on the electrode formation plane except for n-electrode areas, and the negative electrodes having retracted side faces to prevent short-circuiting, using a eutectic bonding material like AuSn for strong electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the distance between p- and n-electrodes is minimized to increase output power, then power increases, but short-circuiting between electrodes occurs due to bonding members
Solution Approach 1:
The patent segments the bonding members into distinct positive and negative bonding members that are electrically isolated from each other. The positive bonding member connects only to the positive electrode, while the negative bonding member connects only to the negative electrode, preventing short-circuiting between electrodes even when the distance between them is minimized.
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the positive and negative bonding members. This insulating layer acts as a mediator that prevents electrical contact between the oppositely charged bonding members, thereby preventing short-circuits while allowing the electrodes to be positioned close together.
2Strength
If Au bump with certain height is used for bonding, then bonding strength increases, but thermal stress causes adhesion failure between light-emitting device and sealing resin
Solution Approach 1:
The patent introduces a buffer layer as an intermediary between the light-emitting device and the sealing resin. This buffer layer absorbs and distributes thermal stress, preventing the stress from directly transferring to the adhesion interface between the light-emitting device and sealing resin, thereby maintaining adhesion reliability while preserving the bonding strength of the Au bump.
Solution Approach 2:
The patent changes the physical parameters of the bonding structure by controlling the height and material composition of the buffer layer. By optimizing the buffer layer thickness and material properties, the thermal stress distribution is modified to protect the adhesion interface while maintaining overall bonding strength.
3Volume of moving object
If distance between light-emitting device and supporting board is reduced, then device size decreases, but short-circuiting between electrodes occurs due to bonding member flow
Solution Approach 1:
The patent segments the bonding members into electrically isolated positive and negative bonding members, each confined to their respective electrode regions. This segmentation prevents the bonding members from bridging between opposite electrodes even when the device size is reduced and the distance between the light-emitting device and supporting board is minimized.
Solution Approach 2:
The patent introduces insulating layers as intermediaries between the positive and negative bonding members. These insulating layers prevent the bonding members from making electrical contact with each other, thereby maintaining electrode isolation even in compact device configurations.
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 configuration effectively prevents short-circuiting while maintaining strong bonding, enhancing light-emitting efficiency and reliability by ensuring accurate electrical connections and alleviating thermal stress, allowing for high-yield fabrication and reliable operation under varying temperatures.
Implementation Method 1
heating and melting the bonding material, thereby bonding the p- and n-electrodes on the light emitting device with the positive and negative electrodes on the supporting board
Implementation Method 2
heating and melting the bonding material, thereby bonding the p- and n-electrodes on the light emitting device with the positive and negative electrodes on the supporting board
Data Source
AI summary
A light-emitting apparatus has a light-emitting device and a supporting board. The light-emitting device has a pair of n-electrodes with a p-electrode therebetween, on the same plane. The supporting board includes an insulating substrate on which positive and negative electrodes are formed, opposing to the p- and n-electrodes of the light-emitting device, respectively. Bonding members bond the p- and n-electrodes with the positive and negative electrodes, respectively. The positive electrode on the supporting board is formed within the width region of the p-electrode and narrower in width than the width of the p-electrode, in a cross-section along a line extending through the pair of n-electrodes. The negative electrodes oppose to the n-electrodes, respectively, with the same widths, or with that side face of each of the negative electrodes which faces the positive electrode being retracted outwardly from that side face of each of the n-electrodes which faces the p-electrode.