LED Chip Electrode Layout for Wire Bonding and Current Blocking

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Solution Overview

Problem

The existing LED chip structures face challenges during wire bonding due to increased force on the current blocking layer, leading to breakage and weakened current blocking effects, which affects the reliability and uniformity of current distribution.

Innovation Solution

The LED chip design includes a current blocking layer with distinct portions and a current expansion layer that defines specific gaps, allowing the electrode structure to cover the blocking layer and reduce direct contact areas, thereby increasing adhesive force and reducing stress on the blocking layer during wire bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the electrode pad contacts the current expansion layer at the edge, then the current distribution uniformity is improved, but the current blocking layer is prone to breakage during wire bonding

Engineering Contradiction:

Improvecurrent distribution uniformityVSAvoidcurrent blocking layer integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The current blocking layer is divided into a first portion and a second portion, with the first portion having a smaller area than the second portion. This segmentation allows the first portion to be positioned within gaps of the current expansion layer, reducing stress concentration during wire bonding while the second portion maintains adequate current blocking capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode structure serves as an intermediary element that covers the first portion of the current blocking layer. By positioning the electrode pad to cover the first portion and extend to contact the current expansion layer, the electrode structure mediates between the current blocking layer and the current expansion layer, distributing mechanical stress during wire bonding and preventing direct stress transmission to the current blocking layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the current blocking layer blocks current vertically downward, then the current blocking effect is improved, but the wire bonding process becomes difficult due to increased force on the current blocking layer

Engineering Contradiction:

Improvecurrent blocking effectVSAvoidwire bonding processability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Different portions of the current blocking layer are designed with different areas and functions. The first portion has a smaller area and is positioned within the current expansion layer gaps to reduce stress during wire bonding, while the second portion has a larger area to maintain effective current blocking. This local quality differentiation allows the structure to simultaneously achieve ease of wire bonding and effective current blocking.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electrode structure is designed to extend in multiple dimensions: it covers the first portion of the current blocking layer in the horizontal plane, and its extension strip contacts both the second portion of the current blocking layer and the current expansion layer. This multi-dimensional configuration allows the electrode structure to provide mechanical support during wire bonding while maintaining the vertical current blocking function of the current blocking layer.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If the electrode pad contacts the semiconductor layer directly, then the adhesive force is improved, but the current blocking layer is more susceptible to breakage

Engineering Contradiction:

Improveelectrode pad adhesive forceVSAvoidcurrent blocking layer stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The electrode structure acts as an intermediary that covers the first portion of the current blocking layer. The electrode pad is positioned to cover the first portion and extend to contact the current expansion layer, which in turn contacts the semiconductor layer. This intermediary configuration allows the electrode structure to distribute mechanical stresses during wire bonding, protecting the current blocking layer from breakage while maintaining adequate adhesive force through the multi-layer contact structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20240421251A1Light-emitting diode chip and light-emitting device

Publication Date: 2024.12.19 XIAMEN SANAN OPTOELECTRONICS CO LTD

AI summary

A LED chip includes a current blocking layer that includes a first portion and a second portion and a current expansion layer defined with a first opening; and the first portion is disposed in the first opening of the current expansion layer. A first gap is defined between the first portion and the current expansion layer; a second gap is defined between the first portion and the second portion; an electrode structure covers the first portion and is in contact with an upper surface of a semiconductor light-emitting sequence stacking layer through the first gap; at least a portion of an extension strip is formed on the second portion of the current blocking layer and the current expansion layer; a part of an edge of the first opening of the current expansion layer is disposed on the second portion of the current blocking layer.