LED Array Alignment Material for Thermal Expansion Mismatch
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Solution Overview
Problem
Bonding semiconductor materials with different coefficients of thermal expansion is challenging due to misalignment issues during temperature changes, leading to faulty devices as the materials expand at different rates, causing contact point misalignment during the bonding process.
Innovation Solution
Incorporating an alignment material with a unique coefficient of thermal expansion between the electrodes of the LED array and the backplane to restrict expansion and maintain alignment during the bonding process, using materials like amorphous silicon or tantalum dioxidefluoride, which are deposited between individual components of the LED array to ensure proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bonding is performed between materials with different coefficients of thermal expansion, then heterogeneous hybridization is achieved, but misalignment occurs during temperature changes
Solution Approach 1:
An alignment material is deposited between the LED array and backplane to act as an intermediary layer. This alignment material has a coefficient of thermal expansion that compensates for the mismatch between the LED array and backplane, thereby maintaining alignment of contact points during temperature changes and bonding processes.
Solution Approach 2:
The coefficient of thermal expansion of the alignment material is specifically selected to be different from both the LED array and backplane materials. By changing this physical parameter, the alignment material compensates for differential expansion and contraction, maintaining precise alignment throughout the bonding process and operational temperature variations.
2Manufacturing precision
If alignment material is deposited between LED array components, then alignment is maintained during bonding, but device complexity increases
Solution Approach 1:
The alignment material is deposited in advance between the LED array components before the bonding process begins. This preliminary action ensures that when bonding occurs, the alignment is already established and maintained, simplifying the actual bonding operation and reducing the need for complex real-time alignment control mechanisms.
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 alignment material effectively maintains electrode alignment during bonding and cooling, ensuring reliable electrical connections and reducing stress-induced bond failures by matching the thermal expansion of the materials, resulting in improved device reliability.
Implementation Method 1
an alignment material having a coefficient of thermal expansion different than a coefficient of thermal expansion of the material of the LED array is deposited between individual components of the LED array. The alignment material restricts the expansion of the LED array during the bonding process
Data Source
AI summary
Embodiments described herein relate to maintaining alignment between materials having different coefficients of thermal expansion during a bonding process of a light emitting diode (LED) device. The LED device includes a LED array and a backplane. The LED array and the blackplane each include a plurality of electrodes. During a bonding process where the electrodes of the LED array and electrodes of a backplane are bonded together, an alignment material having a coefficient of thermal expansion different than a coefficient of thermal expansion of the material of the LED array is deposited between LEDs of the LED array.