3D Micro Display Semiconductor Device via Oxide-to-Oxide Bonding
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Solution Overview
Problem
Current methods for constructing RGB LEDs are inefficient and costly, particularly due to issues with light mixing, thermal expansion coefficient mismatches, and high processing temperatures, which affect the performance and cost-effectiveness of RGB LEDs and microdisplays.
Innovation Solution
The use of smart layer transfer techniques such as ion-cut, laser lift-off, and oxide-to-oxide bonding to stack red, green, and blue LEDs, allowing for efficient light emission with reduced thermal stress and lower processing temperatures, enabling the construction of efficient and cost-effective RGB LEDs and microdisplays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to construct RGB LEDs, then the device can be manufactured, but thermal expansion coefficient mismatches cause high thermal stress and processing temperatures increase costs
Solution Approach 1:
The patent segments the RGB LED into separate red, green, and blue LED layers that are independently fabricated and then stacked. This segmentation allows each layer to be optimized for its specific material properties and thermal characteristics, reducing thermal expansion mismatches compared to conventional single-substrate approaches.
Solution Approach 2:
The patent introduces an intermediary bonding process using smart layer transfer techniques and oxide-to-oxide bonding to join the separate LED layers. This intermediary bonding method reduces thermal stress by creating compliant interfaces between layers with different thermal expansion coefficients, avoiding the high thermal stress of direct conventional bonding.
2Manufacturing precision
If smart layer transfer techniques are used to stack LED layers, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-fabricating each LED layer (red, green, blue) separately with their respective contacts and structures before stacking. This preliminary fabrication of individual layers allows for precise control and optimization of each layer independently, improving overall manufacturing precision despite the multi-step process.
Solution Approach 2:
The patent replaces conventional mechanical bonding methods with smart layer transfer techniques and oxide-to-oxide bonding. This substitution enables higher manufacturing precision through controlled material transfer and chemical bonding mechanisms, achieving superior layer alignment and interface quality compared to traditional mechanical assembly.
3Productivity
If conventional LED construction methods are used, then the process is simpler, but light mixing issues reduce efficiency
Solution Approach 1:
The patent transitions from conventional planar LED construction to a three-dimensional stacked architecture. By stacking red, green, and blue LED layers vertically in the third dimension, the patent eliminates light mixing issues that plague planar designs, allowing each layer to emit light independently in its designated color without interference from other color layers.
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 enables the production of RGB LEDs with improved efficiency and reduced costs by minimizing thermal expansion coefficient mismatches and processing temperatures, enhancing the performance and cost-effectiveness of RGB LEDs and microdisplays.
Implementation Method 1
an oxide layer disposed between the first level and the second level, where the second level is bonded to the oxide layer, and where the bonded includes oxide to oxide bonds
Implementation Method 2
laser lift-off, and oxide-to-oxide bonding to stack red, green, and blue LEDs
Implementation Method 3
smart layer transfer techniques such as ion-cut
Data Source
AI summary
A 3D micro display, the 3D micro display including: a first level including a first single crystal layer, the first single crystal layer includes at least one LED driving circuit; a second level including a first plurality of light emitting diodes (LEDs), the first plurality of LEDs including a second single crystal layer, where the second level is disposed on top of the first level, where the second level includes at least ten individual first LED pixels; and a bonding structure, where the bonding structure includes oxide to oxide bonding.