Hybrid LED Bonding for Thermal Mismatch Alignment
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Solution Overview
Problem
Current LED bonding methods face challenges in achieving precise alignment and thermal expansion coefficient mismatch, leading to run-out issues between contacts, which affect the efficiency and reliability of LED arrays in display systems.
Innovation Solution
A hybrid bonding method is employed, involving dielectric bonding at room temperature followed by metal bonding at elevated temperatures, with the inclusion of thermal expansion coefficient compensation layers and trench formation to align and secure contacts, ensuring precise alignment and reduced run-out between contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LED bonding methods are used, then the bonding process is simple, but alignment precision between contacts deteriorates due to thermal expansion coefficient mismatch
Solution Approach 1:
The patent applies parameter changes by performing dielectric bonding at room temperature to avoid thermal expansion issues during alignment, then subsequently performing metal bonding at elevated temperatures. This sequential temperature approach resolves the thermal expansion coefficient mismatch problem while maintaining bonding effectiveness.
Solution Approach 2:
The bonding process is segmented into two distinct stages: dielectric bonding and metal bonding. Each stage uses optimized conditions (room temperature for dielectric, elevated temperature for metal) to achieve the best results for that specific bonding type, thereby improving overall alignment precision.
2Manufacturing precision
If thermal expansion coefficient compensation layers are added, then run-out between contacts is reduced, but device structure becomes more complex
Solution Approach 1:
The patent introduces thermal expansion coefficient compensation layers with specific material properties that counteract the thermal expansion mismatch between different components. By carefully selecting materials with appropriate thermal expansion coefficients, the run-out between contacts is minimized during the elevated temperature metal bonding process.
3Reliability
If hybrid bonding method is used, then bonding reliability is improved, but manufacturing process becomes more complex
Solution Approach 1:
The hybrid bonding approach segments the bonding process into dielectric bonding and metal bonding steps, each optimized for its specific requirements. This segmentation improves reliability by ensuring proper alignment and bonding conditions for each type, despite increasing process complexity.
Solution Approach 2:
Dielectric bonding is performed as a preliminary action at room temperature to establish precise alignment and mechanical bonding before the metal bonding step. This preliminary alignment ensures that subsequent metal bonding occurs with minimal run-out, improving overall bonding reliability.
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 enhances the precision and reliability of LED arrays by minimizing run-out and thermal expansion-related issues, improving the performance and efficiency of LED arrays in display systems, such as near-eye displays.
Implementation Method 1
performing dielectric bonding of a first dielectric material of the first component with a second dielectric material of the second component at a first temperature
Implementation Method 2
performing metal bonding of the first contacts of the first component with the second contacts of the second component by annealing the first contacts and the second contacts at a second temperature
Implementation Method 3
thermal expansion coefficient mismatch, leading to run-out issues between contacts
Data Source
AI summary
Disclosed herein are techniques for bonding LED components. According to certain embodiments, a first component is bonded to a second component using dielectric bonding and metal bonding. The first component includes an active light emitting layer between oppositely doped semiconductor layers. The second component includes a substrate having a different thermal expansion coefficient than the first component. First contacts of the first component are aligned to second contacts of the second component. A dielectric material of the first component is then bonded to a dielectric material of the second component. The metal bonding is performed between the first contacts and the second contacts, after the dielectric bonding, and using annealing. The bonded structure has a concave or convex shape before the metal bonding. Run-out between the first contacts and the second contacts is compensated through temperature-induced changes in a curvature of the bonded structure during the metal bonding.