Bonded Light-Emitting Wafer With Inclusion Height Control
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Solution Overview
Problem
The presence of spike-shaped inclusions on epitaxial wafers, caused by foreign matter during epitaxial growth, leads to bonding failures when these wafers are bonded to a to-be-bonded substrate, resulting in non-uniform light emission and reduced yield due to light scattering and absorption.
Innovation Solution
The spike-shaped inclusions are fractured to a height equal to or less than the thickness of the adhesive layer before bonding, using a protective film and pressure, to minimize the area of bonding failure and suppress particle scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spike-shaped inclusions are present on the epitaxial wafer surface, then the epitaxial growth can proceed without interruption, but bonding failures occur and particles scatter during bonding, reducing yield and uniformity
Solution Approach 1:
The patent applies preliminary action by performing inclusion removal treatment on the epitaxial wafer surface before the bonding process. This pre-treatment eliminates spike-shaped inclusions that would otherwise cause bonding failures and particle scattering, ensuring high-quality bonding without interrupting the epitaxial growth process itself.
2Productivity
If the precipitate is allowed to fall on the epitaxial layer during growth, then the epitaxial growth can continue, but the precipitate forms spike-shaped protrusions that cause bonding failures
Solution Approach 1:
The patent extracts and removes the harmful spike-shaped inclusions from the epitaxial wafer surface through a dedicated removal treatment process. This extraction eliminates the protrusions that cause bonding failures while preserving the underlying epitaxial layer structure and continuity.
3Strength
If particles are scattered during bonding due to inclusion fracturing, then the bonding interface is compromised, but light scattering and absorption increase, reducing device uniformity
Solution Approach 1:
The patent applies preliminary anti-action by removing inclusions before bonding to prevent the harmful effect of particle scattering. By eliminating the source of particles (spike-shaped inclusions) prior to the bonding process, the method prevents both bonding interface compromise and subsequent light scattering/absorption issues in the finished device.
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 approach reduces the area of bonding failure and minimizes particle scattering, leading to improved uniformity of light emission and increased yield in the production of bonded light-emitting device wafers.
Implementation Method 1
the epitaxial wafer and the transparent substrate being bonded via an adhesive layer with both visible light-transmissive and ultraviolet light non-transmissive
Implementation Method 2
The spike-shaped inclusions are fractured to a height equal to or less than the thickness of the adhesive layer before bonding, using a protective film and pressure
Data Source
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AI summary
The present invention is a bonded light-emitting device wafer including an epitaxial wafer for a light-emitting device including an epitaxial layer that includes an active layer, a transparent substrate with both visible light-transmissive and ultraviolet light-transmissive, and the epitaxial wafer and the transparent substrate being bonded via an adhesive layer with both visible light-transmissive and ultraviolet light non-transmissive, in which a protruding height of a spike-shaped inclusion, which is inherently present in the epitaxial layer, from the epitaxial layer is equal to or less than a thickness of the adhesive layer. This provides the bonded light-emitting device wafer having a narrow failure portion area generated by the spike-shaped inclusion, in which the bonded light-emitting device wafer includes the epitaxial wafer having the spike-shaped inclusion thereon and a transparent substrate with both visible light-transmissive and ultraviolet light-transmissive are bonded via the adhesive layer with both visible light-transmissive and ultraviolet light non-transmissive.