Compliant Electrostatic Transfer Head Spring Support Layer
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Solution Overview
Problem
Integration and packaging of micro devices such as RF MEMS microswitches and LED display systems face challenges due to variations in device height and substrate surface profiles, leading to incomplete transfer and potential damage during traditional transfer processes.
Innovation Solution
A compliant electrostatic transfer head with a spring support layer and patterned device layer, featuring a bipolar electrode configuration, is developed to compensate for height variations and ensure precise contact and transfer of micro devices by deflecting towards a cavity in the base substrate, allowing for improved contact and reduced compressive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional transfer processes are used, then transfer simplicity is maintained, but transfer completeness deteriorates due to height variations causing incomplete transfer and potential device damage
Solution Approach 1:
The transfer head incorporates a spring support layer that enables dynamic deflection toward the cavity, allowing the rigid transfer head to adapt its shape and compensate for height variations in devices and substrate surfaces, thereby achieving complete transfer without damage
Solution Approach 2:
The patent changes the mechanical parameter of the transfer head by introducing a compliant spring support layer with specific elastic properties, enabling the structure to deflect and adapt to varying device heights while maintaining transfer effectiveness
2Adaptability or versatility
If compliant structure with spring support layer is introduced, then adaptability to height variations is improved, but device complexity increases
Solution Approach 1:
The spring support layer functions as a flexible thin film structure that provides compliance to the transfer head, enabling it to adapt to height variations while maintaining a relatively simple overall structure that can be integrated into existing transfer systems
3Manufacturing precision
If electrostatic transfer head deflects toward cavity, then contact precision is improved, but manufacturing complexity increases
Solution Approach 1:
The transfer head is segmented into distinct functional layers including the base substrate, spring support layer, and device layer, with the cavity providing a defined deflection target. This segmentation allows each layer to be optimized and fabricated using standard semiconductor processes, managing manufacturing complexity
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 compliant electrostatic transfer head enables efficient and precise transfer of micro devices with reduced risk of damage, ensuring complete pick-up and integration into heterogeneous systems, including large area displays, at high transfer rates.
Implementation Method 1
compliant electrostatic transfer head
Implementation Method 2
spring support layer beam profile that extends over and is deflectable toward the cavity
Implementation Method 3
method of transferring one or more micro devices to a receiving substrate
Data Source
AI summary
A compliant electrostatic transfer head and method of forming a compliant electrostatic transfer head are described. In an embodiment, a compliant electrostatic transfer head includes a cavity in a base substrate, a spring support layer on the base substrate, and a patterned device layer on the spring support layer. The spring support layer includes a spring support layer beam profile that extends over and is deflectable toward the cavity, and the patterned device layer includes an electrode beam profile that is supported by the spring support layer beam profile and extends over and is deflectable toward the cavity.