Optoelectronic Device Manufacturing via Sequential Substrate Bonding
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Solution Overview
Problem
The existing manufacturing methods for optoelectronic devices, such as emissive display devices with gallium nitride LEDs, face challenges in aligning control circuits and LED matrices, particularly at higher pixel densities, which hinders resolution and integration density improvements.
Innovation Solution
A method involving the growth of a semiconductor stack on a substrate, followed by sequential bonding and removal of substrates to form chips, which are then aligned with control circuits, allowing for precise electrical connection and subsequent delimitation of LEDs without stringent alignment requirements during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control circuit and LED matrix are manufactured separately and then hybridized by stacking, then the device can be assembled with modular components, but the alignment precision deteriorates when pixel pitch decreases
Solution Approach 1:
The LED matrix is transferred to the control circuit substrate before the individual LED positions are defined. This preliminary transfer action allows the substrate structure to be established first, and then the LED positions are precisely defined through subsequent structuring operations, avoiding the need for high-precision alignment during the transfer step itself.
Solution Approach 2:
The manufacturing process is segmented into distinct stages: first transferring the continuous LED matrix, then structuring the substrate to define individual LED positions, and finally connecting each LED to its corresponding control circuit pad. This segmentation allows each step to be optimized independently, with the structuring step providing the necessary precision.
2Manufacturing precision
If the positions of individual LEDs are defined during the transfer step, then alignment can be controlled, but the process complexity and alignment difficulty increase when pixel pitch decreases
Solution Approach 1:
The substrate structure is prepared in advance with metal pads and insulating layers, but the LED positions are not defined during the transfer step. Instead, the continuous LED matrix is transferred first, and then the substrate is structured to define individual LED positions through trench formation and selective insulation, separating the transfer operation from the positioning operation.
3Manufacturing precision
If alignment accuracy is increased through stringent alignment requirements, then LED-to-pad connection precision improves, but the manufacturing time and process difficulty increase
Solution Approach 1:
The substrate is prepared with all necessary metal pads, insulating layers, and structural features before the LED matrix is transferred. This preliminary preparation ensures that when the LEDs are positioned and connected, the precise alignment is achieved through the pre-structured substrate features rather than through complex real-time alignment procedures during transfer.
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 method enhances alignment precision and reduces material losses, enabling higher pixel densities and resolution in optoelectronic devices by decoupling alignment from initial transfer steps and allowing for more flexible and precise structuring of LEDs post-transfer.
Implementation Method 1
the second substrate is fixed on the face of the stack opposite the first substrate by direct bonding of a first metallic layer previously deposited on the face of the stack opposite the first substrate with a second metallic layer previously deposited on the second substrate
Implementation Method 2
the third substrate is fixed on a face of the stack opposite the second substrate by direct bonding of a first dielectric layer previously deposited on the face of the stack opposite the second substrate with a second dielectric layer previously deposited on the third substrate
Data Source
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AI summary
The present application relates to a method for manufacturing optoelectronic devices, comprising the following successive steps: a) growing, on one face of a first substrate, a stack comprising at least one semiconductor layer (123, 125, 127); b) fixing a second substrate on a face of the stack opposite the first substrate, then removing the first substrate; c) fixing a third substrate (151) on a face of the stack opposite the second substrate, then removing the second substrate; d) cutting the assembly comprising the third substrate (151) and the stack into a plurality of first chips (160) each comprising a portion of the stack; and e) fixing each first chip (160), by its face opposite the third substrate (151), onto a face of a fourth semiconductor substrate (170) in and on which a plurality of control integrated circuits (171) have been previously formed.