Semiconductor Light Emitting Element Buffer Layer Stress Relaxation
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Solution Overview
Problem
The existing method for manufacturing thin film LEDs often results in peeling at the interface during the dicing process due to hardened bonding layers, leading to decreased yield and increased manufacturing costs.
Innovation Solution
Incorporating a softer buffer layer made of gold between the bonding layer and the LED layer, which is softer than the gold-indium alloy bonding layer, to relax mechanical stress and prevent peeling during dicing, along with barrier layers to suppress reactions and maintain the buffer layer's soft state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a gold-indium alloy bonding layer is used to bond the LED layer to the support substrate, then bonding strength is improved, but the bonding layer hardens and causes peeling at the interface during dicing
Solution Approach 1:
A buffer layer made of softer gold is introduced between the hardened gold-indium alloy bonding layer and the LED layer. This buffer layer acts as an intermediary that absorbs mechanical stress during dicing, preventing peeling at the interface while the bonding layer maintains its strong bonding function.
Solution Approach 2:
The invention changes the physical parameter (hardness) of the bonding layer by using a two-layer structure: a harder gold-indium alloy layer for bonding strength and a softer pure gold buffer layer for stress absorption. This parameter differentiation resolves the contradiction between bonding strength and interface stability.
2Reliability
If the bonding layer is made harder to ensure bonding strength, then bonding reliability is improved, but manufacturing precision decreases due to peeling during dicing
Solution Approach 1:
The softer gold buffer layer serves as a mediator between the hardened bonding layer and the LED layer, protecting the interface from peeling during dicing operations and thereby maintaining manufacturing precision while preserving bonding reliability.
Solution Approach 2:
The buffer layer is positioned beforehand to cushion and absorb the mechanical stresses that will occur during subsequent dicing operations, preventing damage to the bonding interface and ensuring precise element separation.
3Reliability
If a softer buffer layer is introduced to prevent peeling during dicing, then interface stability is improved, but device complexity increases
Solution Approach 1:
The invention modifies the existing bonding layer by changing its hardness parameter through a two-layer structure, adding only one additional layer (the buffer layer) rather than fundamentally redesigning the bonding system. This minimal structural change maintains simplicity while improving interface stability.
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 buffer layer effectively reduces peeling at the interface during dicing, enhancing the yield of semiconductor light emitting elements and maintaining the buffer layer's softness, thereby reducing manufacturing costs and ensuring high-quality production.
Implementation Method 1
a buffer layer softer than the bonding layer... The buffer layer is placed in one of between the support substrate and the bonding layer and between the bonding layer and the LED layer
Data Source
AI summary
According to one embodiment, a semiconductor light emitting element includes: a support substrate; a bonding layer provided on the support substrate; an LED layer provided on the bonding layer; and a buffer layer softer than the bonding layer. The buffer layer is placed in one of between the support substrate and the bonding layer and between the bonding layer and the LED layer.