Compliant Micro Device Transfer Head Deflection Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional micro device transfer technologies face challenges in efficiently transferring arrays of micro devices due to the need for debonding of the transfer wafer and the involvement of the entire transfer wafer in the process, which can lead to incomplete pick-up and integration issues, especially with variations in device height and contamination.
Innovation Solution
A compliant micro device transfer head with a spring member and deflection sensor is used, allowing for selective pick-up and release of micro devices by measuring deflection to ensure contact and compensate for height variations and contamination, enabling improved contact and transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional transfer wafer bonding is used, then the transfer process can be completed, but the transfer wafer must be debonded from devices after bonding and the entire transfer wafer is involved in the transfer process
Solution Approach 1:
The transfer wafer is divided into individual transfer heads, each capable of independently picking up and transferring single micro devices. This segmentation eliminates the need to handle and debond an entire transfer wafer, reducing complexity while maintaining transfer capability.
Solution Approach 2:
The invention extracts the transfer function from the entire transfer wafer and concentrates it into individual transfer heads. Each transfer head can be independently controlled and positioned, allowing selective transfer of specific devices without involving the rest of the transfer wafer.
2Reliability
If rigid transfer heads are used, then the structure is simple, but complete contact with micro devices cannot be ensured when there are variations in device height or contamination present
Solution Approach 1:
The transfer heads are designed with compliant, spring-like structures that can dynamically adjust their position and contact pressure. This compliance allows each transfer head to adapt to variations in micro device height and contamination, ensuring reliable contact without requiring complex active control systems.
Solution Approach 2:
The transfer heads utilize elastic deformation of spring members to change their physical state from a rigid position to a compliant contact state. This parameter change in stiffness allows the transfer heads to maintain consistent contact force across devices with varying heights and surface conditions.
3Productivity
If the entire transfer wafer is used for transfer, then the process is simple, but transfer time increases and efficiency decreases
Solution Approach 1:
By segmenting the transfer wafer into multiple independent transfer heads arranged in an array, the system can perform parallel transfer operations across multiple devices simultaneously. This segmentation enables the transfer process to proceed in parallel rather than sequentially, dramatically reducing total transfer time.
Solution Approach 2:
The array of transfer heads allows continuous transfer operation where multiple devices are transferred in parallel without interruption. While one transfer head is transferring a device, others can be preparing for or completing transfers, maintaining continuous productive action across the entire array.
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 micro device transfer head enables precise and efficient pick-up and transfer of micro devices by ensuring contact with each device, even with height variations and contamination, resulting in improved integration and assembly rates.
Implementation Method 1
a spring portion deflectable into a space between the spring portion and the base substrate
Implementation Method 2
The sensor may measure strain or capacitance to determine the amount of deflection of the spring portion
Implementation Method 3
an array of the compliant micro device transfer heads... into contact with an array of micro devices... each transfer head may then be selectively activated
Data Source
AI summary
A compliant micro device transfer head and head array are disclosed. In an embodiment a micro device transfer head includes a spring portion that is deflectable into a space between a base substrate and the spring portion.